Note: Descriptions are shown in the official language in which they were submitted.
CA 02615567 2014-08-06
LED SPOTLIGHT
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of the filing date of U.S.
Provisional Patent
Application No. 60/875935 filed 20 Dec. 2006 under the title LED SPOTLIGHT.
FIELD OF THE INVENTION
[0002] This invention is related to the general field of LED lamps, and in
particular in some
aspects to the structure for such lamps and in some aspects to the driving
circuitry for such
lamps, and in some aspects to such lamps for inspection (non-destructive
testing).
BACKGROUND OF INVENTION
[0003] LED lamps are known. LEDs are very small, run fairly cool, and are very
efficient. LEDs
are also available in relatively discrete spectra for specific applications
requiring spectra limits,
such as sources of ultraviolet or specific colours. This allows the use of
light sources without
filters for these applications. This keeps costs down, simplifies set-up, and
improves unit
efficiency.
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[0004] Examples of LED light applications include multiple LEDs grouped in a
single
head for low power applications, such as a flashlight or a lamp for an
alternative energy
household. Such lamps often have many LEDs, for example 10 or more, in order
to
produce enough useful light energy.
[0005] Flashlights with light emitting diodes (LEDs) have advantages over
flashlights
with an incandescent lamp as the light source, especially in performance when
the
batteries deteriorate. LEDs do not lose efficiency the way incandescent lamps
do when
the amount of power supplied to the lamp decreases. Another advantage of LED
flashlights is greater spectral content in the blue-green and blue wavelengths
favorable to
night vision compared to flashlights with incandescent lamps.
[0006] Others have used single or multiple LED lamps in leak detection
applications.
[0007] Inspection lamps that cause fluorescence of fluorescent materials are
widely used
for detection of fluorescent materials. For example, fluids that are under
pressure can
include fluorescent dyes; so that, leaks of such fluids can be detected by
illuminating the
leaking fluids with such inspection lamps.
[0008] One common application of inspection lamps is detection of leaks of the
refrigerant in automotive air conditioning systems. Fluorescent dyes that are
mixed with
the lubricant that is present in automotive air conditioning systems typically
visibly
fluoresce when illuminated with blue, violet or near-ultraviolet wavelengths.
Inspection
lamps that would be used for detecting leaks of such fluids would produce
blue, violet or
near-ultraviolet wavelengths.
[0009] In the past, such inspection lamps used incandescent, halogen, or
mercury vapor
light sources. Now that LEDs that produce the useful wavelengths are
available,
inspection lamps can be made that are smaller and lighter, have less power
consumption,
and produce less heat than inspection lamps without LEDs. Furthermore,
inspection
lamps with incandescent, halogen or mercury vapor light sources required
filters to
remove undesired visible wavelengths that interfere with seeing the
fluorescence of
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visible materials, while LEDs often produce little enough of undesired
wavelengths to not
require filters.
[0010] It has been found that wavelengths in or near the range of 395-415
nanometers are
useful for searching for small quantities of visibly fluorescent materials
since
wavelengths of 395-415 nanometers are slightly visible. If the light from an
inspection
lamp is slightly visible, this helps in seeing what is being irradiated with
the inspection
lamp. Wavelengths longer than 415 nanometers are more visible than shorter
wavelengths and typically require the user of the inspection lamp to wear
glasses that
attenuate or block the visible wavelengths that are produced by the inspection
lamp.
[0011] Alternatively, inspection lamps that produce wavelengths near 450
nanometers
have been found to be useful for some purposes. For example, fluorescent dyes
that are
added to some oils and automotive fluids do not respond as well to violet and
some near-
ultraviolet wavelengths as they do to blue wavelengths. As another example,
some body
fluids weakly fluoresce from both ultraviolet and visible wavelengths, while
many fabrics
fluoresce from ultraviolet and violet wavelengths but not blue wavelengths
longer than
approx. 420 nanometers. As a result, police officers searching for body fluids
would use
blue inspection lamps that cause fluorescence of said body fluids but not of
fluorescent
fabrics. Typically, inspection lamps that produce blue wavelengths such as 450
nanometers would be used with glasses that block the visible wavelengths
produced by
such inspection lamps.
[0012] While LED lamps, such as LED inspection lamps, already exist, they can
be
improved upon or alternatives can be provided therefore.
SUMMARY OF INVENTION
[0013] In some aspects the present invention provides LED inspection lamps
that are
suitable for causing fluorescent materials to fluoresce to assist in the
detection of such
fluorescent materials. Said inspection lamps have one or more LEDs that
typically have a
peak wavelength of 395 to 415 nanometers, although other wavelengths can be
found
useful for such a purpose or for other purposes.
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[0014] LEDs used in such inspection lamps may or may not be high power LEDs
that
require heatsinking. The present invention provides any necessary heatsinking.
Any
embodiment of the present invention may have a thermal cutout device.
[0015] In a first aspect, the present invention is an inspection lamp having
one or more
LEDs aimed generally forwards and producing radiation that is collimated into
a beam by
a concave mirror associated with each of the one or more LEDs.
[0016] In a second aspect, the present invention is an LED inspection lamp
having one or
more LEDs aimed rearwards with a concave mirror behind each of said one or
more
LEDs in order to collimate the radiation from said one or more LEDs into a
beam. The
concave minor to the rear of each of said one or more LEDs may have a
paraboloidal
reflective surface, an ellipsoidal reflective surface, a spherical reflective
surface, or a
different shape reflective surface. An LED may be placed in a position forward
of the
concave mirror so as to produce as intense a beam as possible, so as to
produce a beam
that has an attractive appearance, so as to image the LED chip, or so as to
image another
part of the LED. Other positions of the LED with respect to the concave mirror
may be
used. A sheet of opaque material with a hole in it may be placed forward of
the LED or
around of the tip of the LED and the mirror may form an image of the hole in
order to
produce a beam with a sharp edge.
[0017] In a variation of this second aspect, the present invention has a
single concave
mirror to collimate into a beam the radiation produced by two or more LEDs
that are
aimed generally rearwards.
[0018] In a third aspect, the present invention is an LED inspection lamp
having one or
more LEDs aimed forwards and a lens forward of each of said one or more LEDs
in order
to collimate the radiation from said one or more LEDs into a beam. The lens
forward
from each of said one or more LEDs has at least one aspheric curved surface so
as to
collimate the radiation into a better beam than is available using a spherical
curved lens
surface. Such an aspheric lens surface curve may be paraboloidal, ellipsoidal,
a
combination of paraboloidal and spherical, a combination of paraboloidal and
ellipsoidal,
or a different curve. The LEDs may be directly rearward of the axes of their
respective
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lenses. LEDs that are not on the central axis of the head section of the
inspection lamp
may be placed further from the central axis of the head section of the
inspection lamp
than the axes of their respective lenses are so that the beams formed by the
lenses
converge at a finite distance from the lenses. The LEDs may be placed rearward
of the
lenses such that the lenses image the chips of the LEDs, such that the lenses
image the
front surfaces of the LEDs, or a different position of the LEDs may be found
suitable. A
sheet of opaque material with a hole may be placed around the tip of each LED
or
forward of each LED and a lens forward of each said hole may form a beam that
is an
image of said hole in order to produce a beam with a sharp edge.
[0019] In a fourth aspect, the present invention is an inspection lamp having
one or more
LEDs, wherein the LEDs produce radiation that is collimated into a beam by
transparent
optics that have total internal reflection.
[0020] In a fifth aspect, the present invention is an inspection lamp that has
at least one
LED that produces essentially invisible radiation that is suitable for causing
fluorescence
of fluorescent materials, and at least one other light source that produces
visible light that
illuminates the area being illuminated.
[0021] In a sixth aspect, the present invention is an inspection lamp having
at least one
LED that produces radiation that is suitable for causing fluorescence of
fluorescent
materials, wherein the at least one LED produces a beam of such radiation 10
degrees
wide or narrower without requiring additional optics.
[0022] In a seventh aspect, the present invention is an LED inspection lamp
with a
distinct head and handle connected to each other by a flexible member, wherein
the head
contains at least one LED and wherein the head or other parts of the
inspection lamp
serve as heatsinking for the one or more LEDs.
[0023] Optical surfaces of any lenses or any mirors or reflectors or other
optics used in
the present invention may or may not be faceted. Optical surfaces of any
lenses or any
mirors or reflectors or other optics used in the present invention may or may
not be
textured. Any lenses may be translucent, frosted or textured for purposes such
as
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achieving diffusion. Any embodiment of the present invention may have a filter
to
remove some wavelengths of radiation produced by any LEDs in the present
invention.
Any such filter may be dye based, dichroic, or of an interference type or
colloidal type or
of any other type.
[0024] In any of these aspects the inspection lamp may have a current
regulator circuit to
control the magnitude of the current flowing through the one or more LEDs. The
current
regulator circuit may be a switching current regulator. The current regulator
circuit may
be a boost converter circuit that includes current regulating means. The
current regulator
circuit may include a diode that protects the circuit from any accidental
connecting of a
battery having reversed polarity.
[0025] In any aspect the inspection lamp may include indicator lamps such as a
battery
status indicator lamp. In any aspect the inspection lamp may have a switch.
The switch
may be a momentary switch, a non-momentary switch, or a switch that can be
used as a
momentary switch and as a non-momentary switch.
[0026] In any aspect the present invention may further comprise a charging
jack for
recharging of any rechargeable batteries. In any aspect the present invention
may further
comprise charging circuitry or a charger.
[0027] In any aspect the invention may further comprise means to achieve
strobing any
LEDs.
[0028] In a further aspect the invention provides an LED spotlight including a
housing,
an LED and a reflector within the housing, and a handle that protrudes from
the housing.
the reflector is to collimate light from the LED into a beam. The reflector
has a focal
length. The reflector has a diameter within a range from 3 to 12 inches to
produce
intense illumination of a relatively small area at a distance many times the
focal length of
the reflector and beyond.
[0029] The reflector may have a diameter within a range from 4.5 to 7 inches.
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[0030] The reflector may have a large ratio of depth to diameter such that the
reflector
reflects a large percentage of light produced by the LED into the beam. The
reflector
may be paraboloidal.
[0031] The LED spotlight may be suitable for mounting to a vehicle to direct
the beam
away from the vehicle.
[0032] The LED and the reflector may face forward in the direction of the
beam.
[0033] The LED may face rearward toward the reflector and the reflector may
face
forward in the direction of the beam. With a rearward facing LED, the LED
spotlight
may further include a heatsink mount to which the light emitting diode is
mounted within
the housing. The heatsink mount may include a plurality of spokes extending
radially
away from the LED toward the housing to support the LED in the housing in
place above
the reflector and to conduct heat from the LED.
[0034] In yet another aspect the invention provides an LED spotlight including
a
housing, a plurality of LEDs and a plurality of reflector elements within the
housing, and
a handle that protrudes from the housing. Each reflector element is associated
with a
respective LED to collimate light from the LEDs into a beam. The reflector
elements
have a focal length. The reflector elements together produce intense
illumination of a
relatively small area at a distance many times the focal length of the
reflector elements
and beyond.
[0035] In an eighth aspect the invention provides an LED lamp. The lamp has a
head
section that contains at least one light emitting diode that emits radiation.
The head
section also contains at least one concave reflector. The at least one light
emitting diode
is aimed rearwards towards the at least one concave reflector for receiving
and
collimating a majority of the rearwardly directed radiation into a beam. The
lamp also
has a handle section such that the lamp can be hand held. The head section
further
contains a heatsink mount to which the at least one light emitting diode is
mounted. The
heatsink mount includes a plurality of spokes extending radially away from the
at least
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one LED toward the head section to support the at least one LED in the head
section in
place above the reflector and to conduct heat from the at least one LED.
[0036] The spokes may be equally spaced radially about the at least one LED.
The
heatsink mount may further include an annular ring at which the spokes
terminate, the
ring held in place in the head section by ribs extending inwardly from the
head section.
[0037] The heatsink mount may include at least three spokes.
[0038] The LED may be a white LED.
[0039] In a ninth aspect the invention provides a lamp. The lamp includes a
head section
that contains one or more light emitting diodes, a handle section such that
the inspection
lamp can be hand held, and a lens forward of each of said light emitting
diodes to
collimate the exciting radiation into a beam. The lens forward of at least one
light
emitting diode is aspheric.
[0040] The one or more LEDs radiation may be suitable for exciting fluorescent
materials. Alternatively, the one or more LEDs may be white LEDs.
[0041] More than one LED and more than one associated lens may produce beams
with
the LEDs and assciated lenses arranged to have the beams merge together at a
finite
distance forward of the LED lamp.
[0042] In a tenth aspect the invention provides an inspection lamp suitable
for the
detection of visibly fluorescent materials. The lamp includes an LED that
produces
radiation suitable for causing fluorescence of said fluorescent materials. The
LED is a
side emitting type. The lamp further includes a reflector to collimate the
radiation
produced by said LED into a beam.
[0043] The inspection lamp may further include at least one lens forward of
the reflector,
with the reflector and lens in combination to collimate the radiation produced
by the LED
into a beam.
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[0044] Other aspects of the invention will be evident from the detailed
description and
drawings hereof.
BRIEF DESCRIPTION OF DRAWINGS
[0045] For a better understanding of the present invention and to show more
clearly how
it may be carried into effect, reference will now be made, by way of example,
to the
accompanying drawings that show the preferred embodiment of the present
invention and
in which: [0024] FIG. 1 is a cross sectional side view of a first example
embodiment of
an aspect of the present invention,
[0046] FIG. 2 is a .cross sectional side view of a second example embodiment
of an
aspect the present invention,
[0047] FIG. 3 is a frontal view of the embodiment of FIG. 2,
[0048] FIG. 4 is a cross sectional side view of a third example embodiment of
an aspect
of the present invention,
[0049] FIG. 5 is a cross sectional side view of a fourth example embodiment of
an aspect
of the present invention,
[0050] FIG. 6 is a cross sectional side view of a fifth example embodiment of
an aspect
of the present invention,
[0051] FIG. 7 is a cross sectional side view of a sixth example embodiment of
an aspect
of the present invention,
[0052] FIG. 8 is a cross sectional side view of a seventh example embodiment
of an
aspect of the present invention,
[0053] FIG. 9 is a cross sectional side view of an eighth example embodiment
of an
aspect of the present invention,
[0054] FIG. 10 is a cross sectional side view of a ninth example embodiment of
an aspect
of the present invention,
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[0055] FIG. 11 is a schematic circuit diagram of a first example embodiment of
a circuit
that may be used in an aspect of the present invention,
[0056] FIG. 12 is a schematic circuit diagram of a second example embodiment
of a
circuit that may be used in an aspect of the present invention,
[0057] FIG. 13 is a schematic circuit diagram of a third example embodiment of
a circuit
that may be used in an aspect of the present invention,
[0058] FIG. 14 is a schematic circuit diagram of a fourth example embodiment
of a
circuit that may be used in an aspect of the present invention,
[0059] FIG. 15 is a schematic circuit diagram of a fifth example embodiment of
a circuit
that may be used in an aspect of the present invention,
[0060] FIG. 16 is a schematic circuit diagram of a sixth example embodiment of
a circuit
that may be used in an aspect of the present invention,
[0061] FIG. 17 is a cross sectional side view of a tenth example embodiment of
an aspect
of the present invention,
[0062] FIG. 18 is a cross sectional side view of an eleventh example
embodiment of an
aspect of the present invention,
[0063] FIG. 19 is across sectional side view of a twelfth example embodiment
of an
aspect of the present invention,
[0064] FIG. 20 is a cross sectional side view of a thirteenth example
embodiment of an
aspect of the present invention,
[0065] FIG. 21 is a cross sectional side view of a fourteenth example
embodiment of an
aspect of the present invention, and
[0066] FIG. 22 is a frontal view of an example heatsink used in the embodiment
of FIG.
21.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0067] Throughout this specification a light emitting diode may be referred to
as an LED.
It is to be noted that numerous components are similar for different
embodiments
described herein, and components from one embodiment can be used on other
embodiments. The description for similar components in different embodiments
applies
equally to all embodiments unless the context specifically requires otherwise.
Components from one embodiment can be applied to other embodiments unless the
context specifically requires otherwise, and specific reference to the cross-
application of
such components will not be made for each embodiment, but is expressly stated
hereby.
[0068] Referring to FIG. 1, an inspection lamp 100 resembles a flashlight. It
has a
housing 103, a retainer ring 104 and a window 109.
[0069] The light source is an LED 101.Tthe LED may be a side emitter high
power type
that radiates mainly into directions within 40 degrees of a plane which the
axis of the
LED is normal to. Radiation in said directions is utilized well by the
reflector 102.
Preferably, the reflector 102 is paraboloidal (parabolic) in shape. It can be
ellipsoidal in
shape instead of paraboloidal in order to best direct the radiation from the
LED 101 onto
a target that is a finite distance forward of the inspection lamp 100. Other
reflector shapes
may be found usable for the present invention whether or not such alternative
reflector
shapes are theoretically ideal for the purpose.
[0070] The LED 101 normally requires a heat sink, which may comprise a disk or
cylinder 105, which would be attached to a circular plate 106, which would be
attached to
a short tube 107. Alternative heat sinking arrangements may be used. For
example, it may
be feasible to omit the cylinder or disc 105 depending on the geometry of the
reflector
102. The cylinder or disc 105 and the circular plate 106 may be comprised in a
single
piece of metal. The cylinder 107 may be omitted in alternative embodiments.
One or
more metal rods or metal bars may be attached to the circular plate 108 and
extend
rearward to assist removal of heat from the circular plate 108. Embodiments
may have a
variation of the LED 101 that includes a heat sink.
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[0071] Electrical connections in the inspection lamp 100 are not shown but
will be
evident to those skilled in the art of building flashlights and inspection
lamps.
[0072] The lamp 100 has a battery 111, a power switch 110, and a circuit board
108 that
has a boost converter circuit 200. The boost converter circuit 200 is
necessary for the
battery 111 to power the LED 101 since the voltage required to operate the LED
101 is
greater than that supplied by the battery 101.
[0073] Alternative embodiments can have a battery 111 that has a voltage great
enough to
operate the LED 101. In such a case, the boost converter circuit 200 is not
necessary.
Typically but not necessarily in such a case, in lieu of the boost converter
circuit 200 a
resistor or a current regulator would be used. Such a current regulator may be
a switching
regulator.
[0074] Preferably, the battery 111 is rechargeable. A charging circuit board
113 and a
charging jack 114 are provided so that the battery 111 can be recharged
without removing
it. An indicator lamp 112 is provided and connected to the charging circuit
board 113 to
indicate the charge status of the battery 111. The indicator lamp 112 is
optional. It is to be
noted that some of the connections have been omitted from the FIG. in order to
aid in the
overall clarity of the FIG. Other embodiments can have the battery 111
recharged with an
external charger that does not require the charging circuit board 111. In
other
embodiments the battery 111 may be removed for recharging or may be of a non-
rechargeable type that must be replaced when it is depleted. Alternative
embodiments
may receive power from a power source other than a battery inside the housing
103.
[0075] As shown, the housing 103 comprises a head section 103a and a handle
section
103b and is a single piece of plastic. In other embodiments, the housing 103
may
comprise more than one piece. Part or all of the housing 103 may be of a
material other
than plastic. Part or all of the housing 103 may be metal. Part or all of the
housing 103
may be metal for heat sinking purposes. A part of the handle section 103b may
be
enclosed in rubber or some other non-conductive material to provide a grip
surface.
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[0076] Alternative optical schemes are possible. As an example, the reflector
102 may be -
designed or positioned such that a lens is required forward of the inspection
lamp 100 for
best results.
[0077] Accessories may be provided with the inspection lamp 100. Such
accessories may
or may not be removable from the inspection lamp 100 and may include and are
not
necessarily limited to any combination of the following:
[0078] a) a close-up lens to focus the beam produced by the inspection lamp
100 into a
concentrated spot at a finite distance forward of the inspection lamp 100.
[0079] b) a different optical accessory such as means to widen the beam.
[0080] c) a beam focusing adjustment, such as means to move the LED 101 or the
reflector 102 or an adjustable lens arrangement forward of the reflector 102.
[0081] d) waterproofing means.
[0082] e) means to attach a lanyard to the inspection lamp 100.
[0083] Referring to FIG. 2, a second embodiment inspection lamp 200 resembles
a
flashlight. An LED 201 is provided as a source of radiation that is suitable
for causing
fluorescence of fluorescent materials. The LED is typically a high power type
that
typically requires heatsinking. The radiation from the LED may be mainly of
wavelengths in a narrow spectral band that peaks in the range of 395 to 415
nanometers,
so that the beam produced by the inspection lamp 200 is slightly visible but
not so visible
as to interfere with viewing of any fluorescent material that the inspection
lamp 200
would be used to detect. Longer wavelengths will be found to be better for
some
purposes, but longer wavelengths would typically necessitate use of a viewing
filter or
viewing glasses that block at least most of the visible radiation produced by
the LED 201.
In some applications it would be desirable to use a viewing filter that blocks
at least some
of the exciting wavelengths even if the exciting radiation has a peak
wavelength of 415
nanometers or less. Wavelengths shorter than 395 nanometers may be used where
required to produce fluorescence of materials that require such shorter
wavelengths to
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produce useful fluorescence, or where the visibility of 395-415 nanometers is
excessive.
The LED 201 is aimed rearwards and typically has a wide or moderately wide
radiation
pattern that is easy to collimate into a beam by means of a concave mirror
202. As an
example, the LED 201 may be a Lumileds "Luxeon", one of Nichia's heatsinkable
high
power UV LEDs such as NCCU001E or NCCU033E, or heatsinkable LEDs by ISP. The
LED 201 may alternatively be a lower power type that is sometimes known as a
"high
flux" or "spider" LED and has four leads instead of two in order to dissipate
more heat
than the usual 3 mm and 5 mm types. Alternatively, the LED 201 may be a
different type.
[0084] The LED 201 would typically be attached to a metal bar 203 that serves
as a
heatsink, conducting heat from the LED. The metal bar 203 is attached to a
metal tube
204 that fits inside of the head section of the outer casing 205. The tube 204
serves as
additional heatsink means to conduct heat from the LED and to dissipate said
heat.
Alternatively, if the head section of the outer casing 205 is metal, then the
bar 203 may
be attached directly to the outer casing. Other heatsinking arrangements may
be used.
LEDs can be used for this purpose without heatsinking. A narrow circuit board
may be
attached to or used in place of the metal bar 203.
[0085] The reflecting surface 206 of the concave mirror 202 is ideally
paraboloidal if the
inspection lamp 200 is to be used to illuminate materials at great distances.
The reflecting
surface 206 of the concave mirror 202 is ideally ellipsoidal if the inspection
lamp 200 is
to be used for illuminating materials at close distances. Other shapes of the
reflecting
surface 206 can be found to be usable. Alternatively, a spherical shape for
the reflecting
surface 206 may be used.
[0086] The LED may be placed in a position where the concave minor 202 forms a
beam
consisting of an image of the die or "chip" of the LED 201. The LED 201 may be
positioned such that the beam formed by the concave mirror 202 consists of an
image of
another part of the LED such as the edge of a curved portion of the front
surface. The
LED 201 may be positioned such that no specific part of it is imaged but the
beam may
be optimized for brightness or sharpness of its edge. It may be desirable to
place a sheet
of opaque material having a hole in it forward of the LED 201 or around the
tip of the
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LED 201 so that the beam consists of an image of the hole and has a sharp edge
or other
attractive appearance.
[0087] A battery 207 provides power for the LED 201. The battery may or may
not be
rechargeable. Suitable rechargeable battery types include nickel cadmium,
nickel metal
hydride and lithium ion. The battery may comprise one cell but it is preferred
that the
battery comprise at least two cells. Circuitry 208 that is typically but not
necessarily
mounted on a circuit board 209 is typically necessary for the LED 201 to
operate. The
circuitry 208 may comprise a boost converter, a linear current regulator, a
switching
current regulator, a resistor, or other circuitry that is found to enable the
LED to operate
properly from electrical power supplied by the battery 207.
[0088] A switch 210 is provided to turn the LED on or off. The switch 210 may
be a
momentary switch, a non-momentary switch, or a switch that is usable as either
a
momentary or a non-momentary switch.
[0089] If the battery 207 is rechargeable, then a charging connector 211 may
be provided
so that the battery can be recharged. Alternatively, the battery may be
removable.
Charging circuitry (not shown) that is used to recharge a rechargeable battery
207 may be
but is not necessarily included inside or attached to the inspection lamp 200.
[0090] Wires 212a and 212b are typically provided to connect the LED 201 to
the circuit
board 209. Other wires (not shown) are typically provided to connect the
battery 207 to
the circuit board 209, the switch 210 and the charging connector 211.
[0091] One or more indicator lamps (not shown) may be provided to indicate the
status of
the battery 207 or for other purposes.
[0092] FIG. 3 is a frontal view of the inspection lamp 200 shown in FIG. 2.
Shown are
the LED 201, the concave mirror 202, the metal bar 203, the metal tube 204 and
the outer
casing 205.
[0093] Referring to FIG. 4, a third embodiment inspection lamp 400 that
resembles a
flashlight and has lenses 402 to collimate the light from LEDs 401 into beams
that merge
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together into a single beam. The inspection lamp 400 is similar to one
described in U.S.
Patent Application No. 20020093649, except the curved surfaces 403 of the
lenses 401
are not spherical. The text and drawings of U.S. Patent Application No.
20020093649 is
hereby incorporated by reference into this detailed description. The curved
surfaces 403
may be ellipsoidal. The curved surfaces 403 may have a shape that is a
mathematical
combination of a paraboloid, an ellipsoid and a sphere. Other aspheric shapes
of the
curved surfaces 403 of the lenses 402 may be found to be useful. One shape
that has been
found to be useful is 58% paraboloidal and 42% spherical. This was found
suitable if the
radius of curvature of the central portions of the curved surfaces is 9.6
millimeters, the
overall lens thickness is 4.4 to 5 millimeters, and the refractive index of
the lens material
is 1.5. This results in an effective focal length of 19.2 millimeters. An
equation giving a
curve that is 58% paraboloidal and 42% spherical, with a vertex radius of
curvature R,
is:y¨(0.58*X2/2R)+(0.42*(R-SQR(R2-X2)))Although such a lens
shape is
not quite free of aberrations, it works better than does a lens with a
spherical curved
surface or a paraboloidal curved surface.
[0094] If the curved surfaces 403 are ellipsoidal, then the ellipsoidal
surfaces 403 may be
a portion of an oblate spheroid that has an aspect ratio of or close to 1.55,
since such a
shape has been found to work well.
[0095] The LEDs 401 may be placed directly rearward of their respective lenses
402, so
that the axes of the beams formed thus are parallel to each other and to the
central axis of
the head section of the inspection lamp 400. Alternatively, each of the LEDs
401 that are
not on the axis of the head section of the inspection lamp 400 may be further
from said
axis than the axes of their corresponding lenses 402 are, so that the beams
formed by the
lenses 402 converge at a finite distance forward of the lenses 402. The LEDs
401 may be
positioned so that the beams consist of images of the chips of the LEDs 401
since doing
so typically maximizes the intensity of the beams. The LEDs 401 may be
positioned such
that the beams consist images of the front surfaces of the LEDs 401, since
doing so
typically produces attractive beams with sharp edges. The LEDs 401 may be
positioned
so that no specific parts of them are imaged, although the beams may be
optimized for
brightness or a particular attractive appearance. It is foreseeable that it
may be desirable
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CA 02615567 2007-12-19
to place a sheet of opaque material with a hole forward of or around the tip
of each of the
LEDs 401 so that the beams formed by the lenses consist of images of the holes
to give
the beams a more attractive appearance such as sharp edges.
[0096] The inspection lamp 400 would comprise an outer casing 404, a battery
405,
circuitry 406 that is typically necessary for operation of the LEDs 401, a
switch 407, and
wiring (not shown). The switch 407 may be momentary, non-momentary, or may be
able
to be used either as a momentary switch or a non-momentary switch.
[0097] The LEDs 401 typically have a nominal peak wavelength of 395 to 415
nanometers, although other wavelengths may be found preferable for some
applications.
The LEDs are typically mounted on an LED board 408.
[0098] The circuitry 406 may be a resistor, a linear current regulator, a
switching current
regulator, a boost converter, or other circuitry that permits the LEDs 101 to
be powered
by the battery 405. Preferably the circuit is the switching current regulator
of FIG. 4.
Alternatively, an alternative switching regulator circuit similar to that of
FIG. 5 can be
used, since the circuit shown in FIG. 5 is a boost converter that has
regulation of the
current that flows through a series string of LEDs 401.
[0099] The battery may be rechargeable or non-rechargeable. Suitable
rechargeable
battery types include nickel cadmium, nickel metal hydride, lead-acid,
"sealed"/"gel"
versions of lead-acid, and lithium ion. If the battery is rechargeable and non-
removable,
then it will be necessary to provide a charging connector (not shown). A
charging circuit
(not shown) may be provided in the inspection lamp 400, although in smaller
versions of
this embodiment charging circuitry may, although not necessarily, not be
provided within
the inspection lamp 400.
[0100] One or more indicator lamps (not shown) may be provided to indicate the
status of
the battery 405 or for other purposes.
[0101] A flashlight that is intended to produce visible light, whether white
or of a color
other than white, and having the advantage of aspheric lenses over spherical
lenses
forward of the LEDs may be achieved by placing appropriate LEDs in place of
the
17
CA 02615567 2007-12-19
fluorescence-causing LEDs 401. The replacement of fluorescence causing LEDs
with
LEDs for the production of visible light, whether white or of a color other
than white,
applies equally to all embodiments described herein.
[0102] Referring to FIG. 5, a fourth embodiment is an inspection lamp 500 that
has an
LED 501 and a transparent optic 502 that uses reflection or both refraction
and reflection
to collimate the radiation from the LED 501 into a beam. The transparent optic
502
would typically resemble ones used in the Lumileds "Luxeon with Optics" high
power
LED light sources, but would typically be larger in order to produce a better
beam. The
transparent optics used by Lumileds are typically 20 millimeters in diameter,
and a
transparent optic 502 for the inspection lamp 501 would preferably be 25 to 50
millimeters in diameter.
[0103] Much of the radiation from the LED 501 hits the inner surface 503 of a
hollow
cylindrical region of the transparent optic 502, and as a result is refracted
into a direction
that is more perpendicular to the axis of the transparent optic 502. After
this refraction,
the radiation experiences total internal reflection by the rear surface 504 of
the
transparent optic 502. The total internal reflection directs the radiation
forwards. The
front surface of the transparent optic 502 may be flat or it may be shaped to
refract the
radiation as part of collimating the radiation into a beam.
[0104] The transparent optic 502 and the LED 501 may be separate parts or they
may be
combined into a single unit.
[0105] The rear surface 504 of the transparent optic 502 may be conical,
spherical,
paraboloidal, hyperboloidal, ellipsoidal, or of another shape. The rear
surface 504 of the
transparent optic 502 may comprise zones of different shapes. The front
surface of the
transparent optic 502 may be planar or curved or comprise zones of different
shapes. Any
surface of the transparent optic 502 may be faceted. Any surface of the
transparent optic
502 may be textured for purposes such as smoothing any irregularities in the
beam
produced by the transparent optic 502. Advantages of a textured surface of the
transparent optic 502 may be realized even if transparent optic 502 is of a
typical size of
such a part, such as 20 millimeters in diameter.
18
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[0106] The transparent optic 502 is typically made of a transparent
thermoplastic such as
an acrylic. It may be made of a thermoplastic polycarbonate. Alternatively,
the
transparent optic 502 may be made of a non-thermoplastic polymer such as
epoxy, or a
non-polymer material such as glass or quartz.
[0107] The LED 501 is typically a high power LED that requires heatsinking
means. The
heatsinking means may comprise a metal disc 505 attached to a metal tube 506,
although
other arrangements are possible. The disc 505 and tube 506 would typically be
made of
aluminum, although it is possible that other metals such as steel or copper
may be used.
Any or all of the heatsinking means may be made of diamond should it become
economically feasible to make parts of a heatsinking means from diamond.
[0108] The LED 501 may be a single chip LED such as a Nichia "1 watt" "Luxeon
emitter", an ISP 350 milliamp LED, or an Osram "Golden Dragon" of suitable
wavelength. The LED 501 may be a multi chip LED such as a Lumileds "5 watt"
"Luxeon Emitter", a Norlux "Hex", or an Opto Electronics model in a TO-66
case. Multi
chip LEDs would typically require a larger diameter of the optic 502 to
produce an
adequately narrow beam. An optic 502 larger in diameter than 50 millimeters
may be
used with any LED, but is more likely to be necessary if the LED 502 is a
multi chip
LED with a chip array more than 2 millimeters wide.
[0109] The inspection lamp typically further comprises one or more batteries
503a, which
may or may not be supplied with the inspection lamp. Any batteries 503a may or
may not
be rechargeable. Alternatively or additionally, the inspection lamp 500 may be
able to
receive power from an external power source.
[0110] The inspection lamp 500 typically further comprises one or more
additional
components in a current limiting means 504a that is generally required for
reliable stable
operation of LEDs such as the LED 501. The current limiting means may be a
resistor, a
linear current regulator or a switching current regulator. If the LED requires
a voltage
higher than that supplied by batteries 503a, then the current limiting means
504a may be
a boost converter of limited current output. Such a boost converter used as
the current
limiting means 504a may or may not be a current regulating boost converter.
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[0111] If any batteries 503a are rechargeable, then they may be recharged
through a
charging jack 505a. Circuitry that controls recharging may be included in the
same circuit
board as the current limiting means 504a. The charging jack 505a would be
connected to
rechargeable batteries 503a or charging circuitry that is included with the
current limiting
means 504a by means of charging wires 506a.
[0112] A lens 507 is typically although not necessarily included to protect
internal parts
of the inspection lamp 500 from damage by small falling objects, protruding
objects, and
the like. Typically the front lens 507 would be a planar piece of transparent
material, but
alternatively the front lens 507 may have optical effects on the radiation
emerging from
the optic 502. As shown, the lens 507 may be a fresnel lens, although it may
be a non-
fresnel convex or concave lens.
[0113] Typically the inspection lamp 500 would be designed not to require a
lens other
than a planar lens as the lens 507. However, it may be found desirable for
marketing
purposes to provide an inspection lamp such as the inspection lamp 500 with a
deficiency
that requires a non-planar lens as the lens 507. For example, a non-planar
form of the lens
507 may have an attractive appearance. Attractive front lenses may be used in
embodiments of the present invention other than the inspection lamp 500.
[0114] An inspection lamp such as the inspection lamp 500 may be of such a
design that
the front lens 507 may be removed and replaced with a different version of the
front lens
507. Changing of the front lens may be desirable for changing the
characteristics of the
beam of radiation produced by the inspection lamp 500. For example, the beam
may be
changed from being optimized for longer distances to being optimized for
shorter
distances.
[0115] The front lens 507 may be a filter or a combination of a filter and a
non-filtering
lens. Such a filter, if used, would typically be a filter that blocks
wavelengths longer than
the main fluorescence-causing wavelengths produced by the LED 501. Such a
filter may
be desired if the LED 501 produces some wavelengths that are the same as or
similar to
wavelengths included in the fluorescence of any fluorescent materials to be
detected by
CA 02615567 2007-12-19
use of the inspection lamp 500. Such a filter may be used in other
embodimentsof the
present invention.
[0116] The inspection lamp 500 typically further comprises a switch 508,
associated
switch wiring 509, and an outer casing that may (as shown) comprise a handle
casing
section 510 and a head casing section 511. Any parts or all of the outer
casing may be
part of means to heatsink the LED 501. Any parts or all of the outer casing
may be made
of a metal such as aluminum for heatsinking purposes. Alternatively, any part
or all of the
outer casing may be made of plastic or another material. As shown, the head
casing and
handle casing may both have threads 512 so that the head casing section 511
may be
screwed onto the handle casing section 510. An o-ring 513 may be provided
between
separable parts such as a separate handle section 510 and head section 511 of
the outer
casing if it is desired to have watertightness of the inspection lamp 500.
Other
embodiments of the present invention may be watertight models and such other
watertight embodiments of the present invention may incorporate o-rings.
[0117] Additional parts that the inspection lamp 500 typically includes are
battery
contacts such as a spring 514 and a non-spring contact 515. Any non-spring
contact 515
may be mounted onto the circuit board or assembly that contains the current
limiting
means 504. The inspection lamp 500 may have one or more battery wires 516 for
connecting to the batteries 503 or any of the battery contacts 514 and/or 515.
The
inspection lamp 500 may have wires connecting to the LED 501. The wires 517
may pass
through holes 518 in the heatsink disc 505 or through other parts of any
heatsinking
means. Where any wires 517 pass through any holes 518, glue or moldable
plastic or
rubber or other material may be added for reasons such as achieving
watertightness of
any portion or part of the inspection lamp 500 or reducing any fatigue-causing
movement
of such wires 517.
[0118] The LED 501 may produce radiation whose spectum is a narrow band
peaking at
450 nm, since such a wavelength causes fluorescence of some body fluids but
not of
fabric fibers that have fluorescent optical brighteners added to them. The LED
501 may
have a peak wavelength in the 395-415 nanometer range, which is known to be
useful for
21
CA 02615567 2007-12-19
causing fluorescence of leaks of suitably dyed lubricants associated with
refrigerants in
air conditioning systems and other refrigeration systems. Although other
wavelengths are
also known suitable for detection of refrigerant leaks, the 395-415 nanometer
range is
desirable for being visible enough to see what area is being illuminated with
the radiation
from the LED 501, but not so visible as to excessively interfere with seeing
of fluorescent
dye that has leaked. Wavelengths longer than 415 nanometers typically require
yellow
viewing glasses that block most of the radiation produced by the LED 501.
Wavelengths
slightly shorter than 395 nanometers may be found adequately visible for
seeing the area
being illuminated with radiation from the LED 501, and it is forseeable that
peak
wavelengths as short as 380 nanometers or even shorter may be associated with
adequate
visibility of at least some of the radiation in the main spectral band
produced by the LED
501. LEDs with even shorter peak wavelengths such as 365 nanometers may be
adequately visible, due to either or both of a "long wavelength tail" of the
main
ultraviolet emission band of the LED 501, or a secondary longer wavelength
emission
band produced by LED 501. Ultraviolet LEDs often produce a secondary emission
band
that peaks in the yellow at a wavelength not far from 575 nanometers. The LED
501 may
be an ultraviolet LED that includes or has added to it fluorescent material
that produces a
small amount of visible light. In any version of the LED 501 that has
fluorescent material
added, the purpose of the fluorescent material may be to give some visibility
to the
radiation produced by the LED 501. Alternatively, in any version of the LED
501 that has
fluorescent material added, the original purpose may be different and the
visible
fluorescence may be a side effect. For example, the LED 501 may have an epoxy
body
made with an epoxy that has an ultraviolet stabilizing agent that is slightly
fluorescent.
[0119] The LED 501 may produce radiation of any wavelength that is suitable
for any
application of an inspection lamp. At least two different automotive radiator
coolant dyes
are excited well by wavelengths in or near the range of 460 to 505 nanometers.
Rhodamine 6G, which is used in some forensic work, is excited best by
wavelengths near
530 nanometers. An inspection lamp that produces visible red wavelengths but
not
infrared may be found useful for finding traces of chlorophyll, although such
an
application requires viewing means sensitive to the near-infrared fluorescence
that
chlorophyll has but not sensitive to the visible red wavelengths used to cause
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fluorescence of chlorophyll. The viewing means may be a camera with a suitable
filter.
Such a camera may be a film camera, digital camera, or a camera using a vacuum
imaging tube. If the camera is not a film camera, then the camera or system
using such a
camera may work in real time or may not do so. Any cameras used for viewing
areas
illuminated by one or more inspection lamps may be still cameras or movie
cameras.
[0120] Referring to FIG. 6, a fifth embodiment is an inspection lamp 600 that
has more
than one LED 601, each associated with a transparent optic 602 that relies on
total
internal reflection for collimating the radiation from each of the LEDs 601
into a beam.
[0121] As shown, the LEDs 601 and their associated optics 602 may be arranged
so that
their beams converge at a finite distance or "target distance" forward of the
inspection
lamp 600. Alternatively, the beams formed from each of the LEDs 601 by their
associated optics 602 may be aimed directly forward so as to converge at
infinite distance
and to be essentially converged at far but finite distances.
[0122] The main difference between the inspection lamp 600 shown in FIG. 6 and
the
inspection lamp 500 shown in FIG. 5 is that the inspection lamp 600 shown in
FIG. 6 has
more than one LED 601 with an associated optic transparent 602 that uses total
internal
reflection.
[0123] Any rear surfaces 604 of the transparent optics 602 may be conical,
spherical,
paraboloidal, hyperboloidal, ellipsoidal, or of another shape. Any rear
surfaces 604 of the
transparent optics 602 may or may not comprise zones of different shapes. Any
front
surfaces of the transparent optics 602 may be planar or curved or comprise
zones of
different shapes. Any surface of any of the transparent optics 602 may be
faceted. Any
surface of any of the transparent optics 602 may or may not be textured for
purposes such
as smoothing any irregularities in the beam produced by the transparent optic
602.
Advantages of a textured surface of any of the transparent optics 602 may be
realized
even if transparent optics 602 are of a typical size of such parts, such as 20
millimeters in
diameter.
23
CA 02615567 2007-12-19
[0124] The transparent optics 602 are typically made of a transparent
thermoplastic such
as an acrylic. It may be made of a thermoplastic polycarbonate. Alternatively,
the
transparent optics 602 may be made of a non-thermoplastic polymer such as
epoxy, or a
non-polymer material such as glass or quartz. The transparent optics 602 may
be identical
or non-identical in material, shape, and/or size.
[0125] Any of the LEDs 601 may or may not have their associated transparent
optics 602
combined with them to make LEDs 601 which the transparent optics 602 are an
integral
part of.
[0126] The inspection lamp 600 is shown with one or more batteries 603. Any
batteries
603 may or may not be rechargeable. Alternatively, any embodiment of the
present
invention shown or implemented with batteries can be made in a version that
uses an
external power supply. Such an external power supply may be one or more
external
batteries such as an automotive battery. Alternatively, any external power
supply may be
a non-battery type such as a "wall wart" power supply.
[0127] The inspection lamp 600 is shown with a switch 604. In any embodiment
of the
present invention, such a switch may be momentary, a non-momentary type such
as push-
on/push-off, or a type that can be used both as a non-momentary switch and as
a
momentary switch. For example, the switch 604 may be a switch that is of a
"push-
on/push-off" type that can be usable as a momentary switch if pushed only
partway down
after being "off'. Alternatively, a switch that can be temporarily turned
"off' by being
partially depressed could be used in alternative embodiments of the present
invention.
[0128] The inspection lamp 600 is shown with LED heatsinking means comprising
a
typically metal plate 605 and a typically metal tube 606 that is attached to
the plate 605.
The inspection lamp 600 is shown including an additional non-flat heatsinking
plate 607
which may be desirable in inspection lamps that have heatsinkable LEDs whose
optical
axes are not parallel with each other. Other embodiments of the present
invention may
incorporate similar or other LED heatsinking means.
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[0129] The inspection lamp 600 is shown with a circuit board 608 and
associated
circuitry 609. The circuitry 609 may be one or more resistors or other current
limiting
means that the LEDs 601 typically require. The circuitry 609 may be a boost
converter,
which may be used if any or any combination of the LEDs 601 have a voltage
drop in
excess of the voltage provided by any batteries 603 or provided by any
external power
supply (not shown). If the circuitry 609 comprises a boost converter, the
boost converter
may be a current-regulating boost converter.
[0130] The circuitry 609 may include additional circuitry such as battery
charging control
circuitry or circuitry used for indicating any status of battery condition or
battery
charging or other electronically discernable conditions of the inspection lamp
600. Any
circuitry that could be used in the inspection lamp 600 may be used in other
embodiments
of the present invention.
[0131] The inspection lamp 600 may include a battery contact spring 610 and
typically
includes switch wiring 611. As shown, one of the wires in the switch wiring
611 may
connect the switch to the negative connection of any batteries 603 or of
whatever source
of power is being used. Alternatively, a wire in the switch wiring 611 that
connects the
switch to the power supply may be connected to the positive connection of the
power
supply.
[0132] As shown, the circuit board 608 may have a battery contact 612 to make
contact
with the positive terminal of one of any batteries 603. Alternatively, such a
circuit board
battery contact 612 may contact the negative terminal of one of any batteries
603. Further
alternatively, such a battery contact 612 may be located somewhere other than
on the
circuit board 608 and this may require adding a wire (not shown) to connect
the circuit
board 608 to the battery contact 612.
[0133] Wires 613 may be connected to the LEDs 601. Any wires 613 may pass
through
holes 614 in any parts of any heatsinking means such as the shown heatsinking
plates
605, 607. Any holes such as holes 614 that any wires such as wires 613 pass
through may
be filled with sealing material or material that reduces possibly damaging
movement of
such wires.
CA 02615567 2007-12-19
[0134] The inspection lamp is shown with a single piece outer casing 615.
Alternatively,
embodiments of the present invention can have multiple piece outer casings.
Part or all of
the outer casing 615 may be part of means to heatsink the LEDs 601. The outer
casing
615 may be made of aluminum or another metal for heatsinking purposes.
Alternatively,
part or all of the outer casing 615 may be made of plastic or another
material.
[0135] The inspection lamp 600 includes a front lens 616 that may be a planar
piece of
transparent material. The front lens 616 of the inspection lamp 600 or any
front lens of
alternative embodiments of the present invention may be glass, quartz,
thermoplastic or
non-thermoplastic polymer material. The front lens 616 or any front lens of
alternative
embodiments of the present invention may have filtering characteristics, such
as passing
fluorescence-causing wavelengths of the radiation produced by the LEDs 601
while
blocking wavelengths of radiation produced by the LEDs 601 but also produced
by
fluorescent materials being detected by such an inspection lamp.
[0136] Referring to FIG. 7, a sixth embodiment is an inspection lamp 700 that
comprises
a single LED 701 and an aspheric lens 702 that collimates the radiation from
the LED
701 into a beam. The aspheric lens provides a more sharply focused beam than a
lens
having only one or more spherical surfaces can.
[0137] The aspheric lens 702 may be planoconvex as shown, but alternatively
may be
biconvex or concavoconvex. If the lens 702 has both its front and rear
surfaces curved,
then either or both of these surfaces may have an aspheric curvature. Such an
aspheric
curvature may be paraboloidal, ellipsoidal, hyperboloidal or any combination
of these or
any combination of any of these and spherical curvature. For example, a lens
with a focal
length of 35 millimeters may have a curve that deviates from a flat surface by
the sum, in
terms of deviating from a plane, of a spherical surface that alone results in
a focal length
of 70 millimeters and a paraboloidal surface that alone results in a focal
length of 70
millimeters.
[0138] The aspheric lens 702 may be in a fresnel lens form. If the lens 702
has more than
one non-planar surface, either or both surfaces may be fresnel lens surfaces.
26
CA 02615567 2007-12-19
[0139] The inspection lamp 700 may have a washer (annular ring) 703 that is
placed at or
near the most forward point of the LED 701. The beam produced by the
inspection lamp
700 may be in the form of an image of the hole of the washer 703.
Alternatively, the
beam produced by the inspection lamp 700 may be in the form of an image of a
hole or
transparent region in an object other than the washer 703 or of the edge of
the transparent
body of the LED 701 or of the chip or chip array of the LED 701 or of any
other part of
the LED 701. Further alternatively, the beam produced by the inspection lamp
700 may
not be in the form of a focused image of any part of the inspection lamp 700.
[0140] The inspection lamp 700 as shown further comprises a battery 704, a
circuit board
705, circuitry 706 that the LED 701 typically requires, a switch 707, switch
wiring 708,
an outer casing 709, a battery spring contact 710, one or more battery wires
711, and a
closed loop formation 713 that is provided for attachment of a lanyard. Other
arrangements for an inspection lamp may have a single LED and an aspheric lens
that
collimates the radiation from the LED into a beam.
[0141] Referring to FIG. 8, a seventh embodiment of the present invention is
an
inspection lamp comprising two or more LEDs 801 that are pointed generally
forwards,
with each of the LEDs 801 associated with a concave mirror 802 to collimate
the
radiation produced by the LEDs 801 into a beam. The concave mirrors 802 may be
separate pieces or comprised into a single piece. The concave mirrors 802 may
be metal,
metallized glass or metallized plastic.
[0142] The concave mirrors 802 may or may not have a protective overcoating.
If any
concave mirrors 802 have a protective overcoating, the protective overcoating
may be
silicon dioxide. Any protectiVe overcoating on any concave mirrors 802 may be
a
polymer. Any protective overcoating on any concave mirrors 802 may be sprayed
on or
applied in a manner other than spraying, such as being applied with a
paintbrush or
similar means. Any protective coating may or may not require curing or
solidification
such as by evaporation of a solvent, inherent reaction of chemical ingredients
in the
27
CA 02615567 2007-12-19
protective coating, or oxidation or polymerization. Curing of any protective
coating on
any mirrors 802 may or may not require or be assisted by irradation by
ultraviolet
radiation or other radiation. Any concave mirrors 802 may or may not require
elevated
temperatures in their formation, such as for curing of any protective coating.
[0143] The LEDs 801 may be identical or they may be non-identical. It is
preferred that
at least one of the LEDs 801 produce visible light to an extent such that the
area being
illuminated with the inspection lamp is visible being illuminated. Any of the
LEDs 801
that produces such visible radiation would preferably produce radiation,
whether visible
or in the form of additional invisible radiation, that is suitable for causing
fluorescence of
fluorescent materials to be detected by use of the inspection lamp 800. For
inspection
lamp purposes it is preferred that all of the LEDs 801 produce radiation that
is suitable
for causing fluorescence of materials to be detected, although some
alternative inspection
lamp embodiments of the present invention can have some but not all of the
LEDs 801
producing radiation that is useless for causing fluorescence of at least some
fluorescent
materials.
[0144] The concave surfaces of the mirrors 802 may be spherical or aspheric.
Aspheric
concave surfaces of the mirrors 802 would ideally be paraboloidal for forming
beams that
are best-formed at infinite and long distances, while ellipsoidal concave
surfaces of the
mirrors 802 would be ideal if the inspection lamp 800 is to be optimized for
shorter
distances. Any of the concave mirrors 802 may be faceted or textured.
[0145] The concave mirrors 802 and LEDs 801 may be arranged to form beams that
merge best at infinite distance and nearly enough to do so at far but finite
distances. Such
an arrangement that is optimized for long distances may be found adequate for
use at
shorter distances of a meter or a fraction of a meter forward of the
inspection lamp 800.
Alternatively, the concave mirrors 802 and LEDs 801 may be arranged to form
beams
that are best-merged and best-focused at a finite distance forward of the
inspection lamp
800. Preferably the distance at which the beams are best focused would be the
same
distance that the beams are best merged into each other, although it is
possible that at a
28
CA 02615567 2007-12-19
finite distance forward of the inspection lamp the beams may be best-focused
or best-
merged but not both. It is possible that a variation of the inspection lamp
800 or another
embodiment of the present invention with multiple beams may have its beams
either not
converge or not focus at any finite distance, although it is preferred that
the beams are
both reasonably well defined and reasonably merged into each other at a target
distance
forward of such an inspection lamp that such an inspection lamp would be used
for.
[0146] The inspection lamp 800 typically further comprises a lens 816. The
lens 816 is
typically but not necessarily a planar piece of transparent material, such as
by example
and not limitation glass, quartz, acrylic, thermoplastic polycarbonate, non-
thermoplastic
polycarbonate, or epoxy. The lens 816 may have filtering properties, such as
blockage of
wavelengths produced both by any or all of the LEDs 801 and at least some of
the
fluorescent materials that the inspection lamp 801 is intended to cause
fluorescence of.
[0147] The lens 816 may have refractive properties not achieved by the concave
mirrors
802. A possible purpose of a design of the inspection lamp 800 wherein the
concave
mirrors 802 produce beams requiring refractive action of the lens 816 is to
accommodate
a version of the lens 816 that has a marketable appearance of having a part in
formation
of the beams of radiation that are at least partially formed by the concave
mirrors 802. It
may be found that the concave mirrors 802 could be found to be made smaller or
less
expensive to produce if the lens 816 plays a role in the formation of beams of
radiation
partially formed by the concave mirrors 802 from the LEDs 801.
[0148] The inspection lamp 800 is shown with one or more batteries 803. Any
batteries
803 may or may not be rechargeable. Alternatively, any embodiment shown or
implemented with batteries can be made in a version that uses an external
power supply.
Such an external power supply may be one or more external batteries such as an
automotive battery. Alternatively, any external power supply may be a non-
battery type
such as a "wall wart" power supply.
[0149] The inspection lamp 800 is shown with a switch 804. In any embodiment
of the
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CA 02615567 2007-12-19
present invention, such a switch may be momentary, a non-momentary type such
as push-
on/push-off, or a type that can be used both as a non-momentary switch and as
a
momentary switch. For example, the switch 804 may be a switch that is of a
"push-
on/push-off' type that can be usable as a momentary switch if pushed only
partway down
after being "off'. Alternatively, a switch that can be temporarily turned
"off' by being
partially depressed could be used in alternative embodiments of the present
invention.
[0150] The inspection lamp 800 is shown with LED heatsinking means comprising
a
typically metal plate 805 and a typically metal tube 806 that is attached to
the plate 805.
The inspection lamp 800 is shown including an additional non-flat heatsinking
plate 807
which may be desirable in inspection lamps that have heatsinkable LEDs whose
optical
axes are not parallel with each other. Other embodiments of the present
invention may
incorporate similar or other LED heatsinking means.
[0151] The inspection lamp 800 is shown with a circuit board 808 and
associated
circuitry 809. The circuitry 809 may be one or more resistors or other current
limiting
means that the LEDs 801 typically require. The circuitry 809 may be a boost
converter,
which may be used if any or any combination of the LEDs 801 have a voltage
drop in
excess of the voltage provided by any batteries 803 or provided by any
external power
supply (not shown). If the circuitry 809 comprises a boost converter, the
boost converter
may be a current-regulating boost converter.
[0152] The circuitry 809 may include additional circuitry such as battery
charging control
circuitry or circuitry used for indicating any status of battery condition or
battery
charging or other electronically discernable conditions of the inspection lamp
800. Any
circuitry that could be used in the inspection lamp 800 may be used in other
embodiments
of the present invention.
[0153] The inspection lamp 800 may include a battery contact spring 810 and
typically
includes switch wiring 811. As shown, one of the wires in the switch wiring
811 may
connect the switch to the negative connection of any batteries 803 or of
whatever source
CA 02615567 2007-12-19
of power is being used. Alternatively, a wire in the switch wiring 811 that
connects the
switch to the power supply may be connected to the positive connection of the
power
supply.
[0154] As shown, the circuit board 808 may have a battery contact 812 to make
contact
with the positive terminal of one of one of any batteries 803. Alternatively,
such a circuit
board battery contact 812 may be intended to contact the negative terminal of
one of any
batteries 803. Further alternatively, such a battery contact 812 may be
located somewhere
other than on the circuit board 808 and this may require adding a wire (not
shown) to
connect the circuit board 808 to the battery contact 812.
[0155] Wires 813 may be connected to the LEDs 801. Any wires 813 may pass
through
holes 814 in any parts of any heatsinking means such as the shown heatsinking
plates
805, 807. Any holes such as any holes 814 that any wires such as any wires 813
pass
through may be filled with sealing material or material that reduces any
possibly
damaging movement of such wires.
[0156] The inspection lamp is shown with a single piece outer casing 815.
Alternatively,
embodiments of the present invention can have multiple piece outer casings.
Part or all of
the outer casing 815 may be part of means to heatsink the LEDs 801. The outer
casing
815 may be made of aluminum or another metal for heatsinking purposes.
Alternatively,
part or all of the outer casing 815 may be made of plastic or another
material.
[0157] The inspection lamp 800 includes a front lens 816 that may be a planar
piece of
transparent material. The front lens 816 of the inspection lamp 800 or any
front lens of
alternative embodiments of the present invention may be glass, quartz,
thermoplastic or
non-thermoplastic polymer material. The front lens 816 or any front lens of
alternative
embodiments of the present invention may have filtering characteristics, such
as passing
fluorescence-causing wavelengths of the radiation produced by the LEDs 801
while
blocking wavelengths of radiation produced by the LEDs 801 but also produced
by
fluorescent materials being detected by such an inspection lamp.
31
CA 02615567 2007-12-19
[0158] Referring to FIG. 9, an eighth embodiment is an inspection lamp 900
that
comprises a small cluster of LEDs 901 that are aimed rearwards towards a
single concave
mirror 902. If the inspection lamp is of a design optimized for infinite
distances or longer
distances of a meter or more, then ideally the concave mirror 902 is
paraboloidal and the
LED axes are colinear with lines that both pass through the focal point of the
concave
mirror 902 and points on the surface of the concave mirror 902. If the
inspection lamp
900 is of a design optimized for shorter target distances, then the concave
mirror 902 may
be ellipsoidal with two focal points, a distal focal point at the designed
target distance and
a proximal focal point which the axes of the LEDs 901 ideally pass through. It
is
foreseeable that alternative designs can be found to be workable. Such an
alternative
design may include the concave mirror 902 having a spherical reflective
surface.
[0159] The concave mirror 902 may or may not comprise a plurality of facets.
The
concave mirror 902 may or may not be textured. If the concave mirror 902 is
textured,
this may be done to smooth out irregularities in the beam formed by it or to
achieve an
attractive appearance.
[0160] The concave mirror 902 may or may not have a protective overcoating. If
any
concave mirror 902 have a protective overcoating, the protective overcoating
may be
silicon dioxide. Any protective overcoating on any concave mirror elements 902
may be
a polymer. Any protective overcoating on any concave mirror 902 may be sprayed
on or
applied in a manner other than spraying, such as being applied with a
paintbrush or
similar means. Any protective coating may or may not require curing or
solidification
such as by evaporation of a solvent, inherent reaction of chemical ingredients
in the
protective coating, or oxidation or polymerization. Curing of any protective
coating on
any mirror 902 may or may not require or be assisted by irradation by
ultraviolet
radiation or other radiation. The mirror 902 may or may not require elevated
temperatures
in their formation, such as for curing of any protective coating.
[0161] The inspection lamp 900 typically further comprises a battery 903,
although the
32
CA 02615567 2007-12-19
inspection lamp 900 may alternatively receive power from an external battery
or other
external power source.
[0162] The battery 903 may have both its positive and negative terminals on
one end, as
shown. The inspection lamp typically further comprises a circuit board 904.
Such a
circuit board 904 typically has mounted on it current limiting means 905 that
the LEDs
901 typically require. The current limiting means 905 may comprise one or more
=resistors, one or more linear current regulators, one or more switching
current regulators,
and/or one or more boost converters that have limited current output. Any of
one or more
boost converters used in the current limiting means 905 may have regulated
current
output.
[0163] The inspection lamp 900 typically further comprises an outer casing
906, which is
shown as being of a single piece of material. The outer casing 906 may
alternatively
consist of more than one piece. If the outer casing 906 comprises more than
one piece of
material, then such multiple pieces of the outer casing may or may not be made
of the
same material. For example, part of the outer casing 906 may be made of metal
and part
of the outer casing 906 may be made of a plastic such as ABS, acrylic,
thermoplastic
polycarbonate, polyethylene, polypropylene, polybutylene or "nylon".
[0164] Since the inspection lamp 900 is shown as having a battery 903 having
both its
positive and negative terminals at the same end of the battery 903, the
circuit board 904
can include the typically required battery contacts 907.
[0165] In the inspection lamp 900, the LEDs 901 may but not necessarily
produce
essentially invisible ultraviolet radiation. It is often desirable for
inspection lamps such as
the inspection lamp 900 to produce a beam that is sufficiently visible to
slightly visibly
illuminate the area that is being irradiated by inspection lamps such as the
inspection
lamp 900. Therefore, the inspection lamp 900 may further comprise a visible
light source
908 which may be an incandescent lamp (as shown) or which may be an LED.
33
CA 02615567 2007-12-19
[0166] The inspection lamp 900 typically further comprises a switch 900. -The
switch 900
may be of a non-momentary type, a momentary type, or a type usable both as a
momentary and as a non-momentary switch. The switch 909 typically has
connected to it
switch wires 910. As shown, the switch wires 910 may run to the circuit board
904, but
alternatively at least one of the switch wires 910 may run to a connector for
the battery
903 or to the LEDs 901.
[0167] The LEDs 901 may be mounted to an LED board 911. Such an LED board 911
may be held in place by thin rods 912 (as shown).
[0168] As shown, the LED board 911 may be connected to the circuit board 904
by
means of wires 913.
[0169] The inspection lamp 900 typically includes a front lens 914. The front
lens 914
may have filtering characteristics such as blocking of wavelengths both
produced by the
LEDs 901 and by materials that the inspection lamp 900 is intended to cause
fluorescence
of. The front lens 914 is typically planar but may not be. The concave mirror
902 may be
located or of such curvature that the beam formed by it can be improved by
making the
front lens 914 convex or concave. If the font lens 914 is convex or concave,
it may be
spherical or aspheric. An aspheric version of the front lens 914 may be
ellipsoidal,
paraboloidal, hyperboloidal, a curve that is any mathematical combination of
such shapes
with each other or other shapes, or it may be of another curved shape. A
convex version
of the front lens may be biconvex, planoconvex, concavoconvex or a fresnel
lens. A
concave version of the front lens 914 may be biconcave, planoconcave,
convexoconcave,
or a fresnel lens. The front lens may be translucent, frosted or textured if a
diffusing
characteristic is desirable for purposes such as smoothing irregularities in
the beam
formed by the concave mirror 902.
[0170] The LED board 911 may be attached to the front lens 914.
[0171] In an inspection lamp having a battery that has both terminals on one
end, such as
34
CA 02615567 2007-12-19
the inspection lamp 900 having a battery resembling the shown battery 903, a
piece of
foam rubber 915 may be provided to keep the battery forced into a desirable
position.
Other arrangements are possible where one or more pieces of foam rubber are
desirable
to keep any batteries or other parts forced into a desirable position.
[0172] The inspection lamp 900 may but does not necessarily further comprise a
closed
loop formation 916 that is suitable for attachment of a lanyard.
[0173] Referring to FIG. 10, a ninth embodiment of the present invention is an
inspection
lamp 1000 that has one or more LEDs 1001a that produce invisible or
essentially
invisible ultraviolet radiation, and at least one light source 1001b that
produces radiation
that is more visible. The one or more visible-radiation-producing light
sources 1001b
may be LEDs or non-LED lamps such as incandescent lamps. It is preferred that
the
radiation from the visible-radiation-producing light source(s) 1001b be useful
for causing
fluorescence of fluorescent materials to be detected with the inspection lamp
1000. The
visible radiation produced by the one or more visible-radiation-producing
lamps 1001 b
would typically be used for forming a visible beam that is usually desirable
for indicating
the area that is being illuminated by an inspection lamp such as the
inspection lamp 1000.
This is an alternative to inspection lamps that have a single light source or
more than one
identical light sources that produce radiation that both has a desirable
visibility and
ability to cause fluorescence of fluorescent materials.
[0174] The visible-radiation-producing light source shown in FIG. 10 is a
filament lamp,
but it may be an LED or other light source such as a glow discharge lamp, arc
lamp, or
electroluminescent lamp. More than one visible light source may be used as the
one or
more visible light sources 1001b. If any of the one or more visible light
sources 1001b is
an LED, it may be a less-conventional LED such as a laser diode, an organic
LED, or
polymer LED. If any of the one or more visible light sources is a
semiconducter LED, the
LED chemistry may be but is not necessarily limited to GaAs, GaAlS, GaP,
GaA1P,
GaAlAsP, InGaAsP, GaN, InGaN, or ZnSe. Any visible light source used for the
one or
more visible light sources 1001b may produce any visible wavelength of light,
although it
CA 02615567 2007-12-19
is preferable that such visible light also be useful for causing fluorescent
materials to be
detected by use of the inspection lamp 1000 in addition to the ultraviolet
LEDs 1001a
producing radiation that is useful for this purpose.
[0175] Alternatively, the inspection lamp 1000 can have at least one LED 1001a
that
produces radiation useful for causing fluorescence while at least one
different light source
100lb, whether LED or otherwise, produces radiation that is useful for
determining what
area is being illuminated by the inspection lamp 1000, even if the radiation
produced by
the one or more different light sources 1001b is essentially invisible. For
example, the
radiation produced by the one or more different light sources 100lb may
produce an
illumination pattern that is visible with an infrared camera.
[0176] As a further alternative, the inspection lamp 1000 may comprise at
least one light
source 1001a and at least one different light source 100lb, wherein such an
inspection
lamp is used to detect materials that do not fluoresce but absorb radiation
produced by
either but not both of the first said one or more light sources 1001a or
second said one or
more light sources 100lb. Such an alternative version of the inspection lamp
1000 may
be used to detect materials that are not fluorescent but are illuminated
differently by such
an alternative inspection lamp 1000 than the background material that such
materials to
be detected would exist on. The material to be detected may appear a different
color than
the background material when illuminated by such an alternative form of the
inspection
lamp 1000.
[0177] The inspection lamp 1000 typically comprises additional parts such as
an outer
casing 1002, one or more batteries 1003, a switch 1004, a front lens 1005, a
circuit board
1006, current limiting circuitry 1007, one or more wires 1008 connected to the
switch
1004, and one or more wires or other pieces of conductive material 1009 for
connecting
to the one or more batteries 1003. A spring 1010 may be provided for making
contact
= with any of the one or more batteries 1003. The outer casing 1002 may
have a closed
loop formation 1011 to attach a lanyard to. Other arrangements for the
inspection lamp
1000 are foreseeable.
36
CA 02615567 2007-12-19
[0178] The lens 1005 may be a planar lens or it may be designed to affect the
radiation
from the ultraviolet LEDs 1001a and/or the visible light from the visible
light source
100lb. The lens may comprise an arrangement of lens elements that collimate
the light
from the light sources 1001a, 100lb into a beam. Lens elements that form beams
from
any of the light sources 1001a, 100lb may be spherical convex lenses or
aspheric convex
lenses. Convex lens elements may be biconvex, planoconvex, or concavo-convex.
Biconvex lens elements may have their two convex surfaces idential or non-
identical.
Non-identical convex surfaces of a lens element may have different degrees of
curvature.
Non-identical convex surfaces of a biconvex lens elements may differ in shape,
for
example one surface may be spherical while the other is aspheric. Any lens
elements of
the lens 1005 may be Fresnel lenses.
[0179] The current limiting circuitry 1007 is typically necessary for proper
operation of
the ultraviolet LEDs 1001a. The current limiting circuitry 1007 may be one or
more
resistors, one or more linear current regulator, one or more switching current
regulators,
or one or more boost converters. If a boost converter or other circuit
depending on
switching of inductors or capacitors is used, typically but not necessarily
only one circuit
is used no matter how many ultraviolet LEDs 1001a are provided. The one or
more
sources 1001b may or may not receive power from the current limiting circuitry
1007 that
the ultraviolet LEDs 1001a receive power from. Separate circuitry may be used
to limit
= the current that flows through the one or more visible light sources
100lb.
[0180] Referring to FIG. .11, a boost converter circuit 1100 suitable for use
with LEDs is
provided in the present invention. The positive power wire (not shown)
connects to the
positive power connection point 1120. The negative power wire (not shown) is
connected
to the negative power connection point 1121. In the preferred embodiment of
the present
invention, the supply voltage is nominally 4.8 volts, as obtained from a
battery having
four NiMH cells in series. Other supply voltages can be used in various
embodiments of
the present invention.
37
CA 02615567 2007-12-19
[0181] Ground refers to the negative power supply connection 1121.
[0182] A diode 1104 receives current through a dropping resistor 1105 and is
used as a
voltage reference source. In the preferred embodiment of the present
invention, the diode
1104 is an LED. LEDs have a lower percentage change of voltage drop as
temperature
varies than most other diodes do, although various embodiments of the present
invention
could use a diode 1104 of a type other than an LED. It is forseeable that
alternative
embodiments of the invention can use a diode 1104 of a type other than an LED
and
current received by the diode can be limited by an alternative means to the
dropping
resistor 1105.
[0183] The voltage across the diode 1104 is divided to a reduced reference
voltage by the
voltage divider formed by the two resistors 1106 and 1107. This reduced
reference
voltage is connected to the non-inverting input of a comparator 1101a. It is
forseeable
that in alternative embodiments of the present invention that the anode of the
diode 1104
is connected directly to the non-inverting input of the comparator 1101a and
the resistors
1106 and 1107 are omitted.
[0184] Power supply connections for the comparators 1101a, 1101b and 1101c are
not
shown for simplicity but are provided.
[0185] The comparator 1101a compares the reference voltage received by its non-
inverting input with the voltage across the current sensing resistor 1108, the
ungrounded
end of which is connected to the inverting input of the comparator 1101a. A
positive
feedback resistor 1109 causes the comparator 1101a to have a hysteresis
characteristic.
Because of the positive feedback, the output of the comparator 1101a, if high,
will switch
to low if the voltage across the current resistor is significantly greater
than that would be
delivered to the non-inverting input of the comparator 1101a by the voltage
divider
comprising the two resistors 1106 and 1107 if the positive feedback resistor
1109 did not
exist. The output of the comparator 1101a remains low until the voltage across
the
current sense resistor 1108 decreases to a voltage significantly less than
that would be
38
CA 02615567 2007-12-19
delivered to the non-inverting input of the comparator-1101a by the voltage
divider
comprising the two resistors 1106 and 1107 if the positive feedback resistor
1109 did not
exist.
[0186] If the voltage divider comprising the resistors 1106 and 1107 is
omitted, then an
input resistor (not shown) would be connected from the anode of the diode 1104
to the
non-inverting input of the comparator 1101a so that the hysteresis function of
the
comparator circuit using the comparator 1101a will function.
[0187] The output of the comparator 1101a is alternatively high or low in
order to keep
the voltage across the current sensing resistor 1108 close to the voltage
delivered to the
non-inverting input of the comparator 1101a. When power is first applied, the
initial
current through the inductor 1103 and the current sensing resistor 1108 is
zero. As a
result, the voltage across the current sensing resistor is initially zero.
Since this makes the
voltage of the inverting input of the comparator 1101a lower than the voltage
of its non-
inverting input, the output of the comparator 1101a is high and accordingly it
turns a
transistor 1102 on. This results in the supply voltage, minus any voltage drop
in the
transistor 1102 and the current sensing resistor 1108, to be applied to the
inductor 1103 in
order to increase the current flowing through the inductor 1103 and the
current sensing
resistor 1102. When the voltage across the current sensing resistor 1108
exceeds the
voltage with respect to ground at the non-inverting input of the comparator
1101a, the
comparator switches to its low state and turns the transistor 1102 off Once
this occurs,
current flowing through the inductor 1103 continues to flow but does so
through the
diode 1110 and the LED 101. As long as the combined voltage drops of the LED
101 and
the diode 1110 and that resulting from this current multiplied by the
resistance of the
inductor 1103 exceed the power supply voltage, the current will decrease. When
this
current decreases sufficiently for the voltage across the current sensing
resistor to become
less than the voltage with respect to ground of the non-inverting input of the
comparator
1101a, the output of the comparator 1101a becomes high. This operation is a
repeating
cycle.
39
CA 02615567 2007-12-19
[0188] This cyclic operation attempts to regulate the current that flows
through the
current sensing resistor 1108 and accordingly through the inductor 1103.
Ideally, this
quantity of current multiplied by the supply voltage is the quantity of power
delivered to
the LED 101. Losses from this, which are to be minimized in ways known to
those
skilled in the art of designing and constructing switching power supply
circuits, are small
compared to the power delivered to the LED 101 if they are appropriately
minimized.
Accordingly, the amount of power delivered to the LED 101 is the supply
voltage
multiplied by the regulated average value of the current flowing through the
current
sensing resistor 1108, minus said losses. This means that the power delivered
to the LED
101 will vary roughly proportionately with the supply voltage. Since the
voltage
delivered by most rechargeable batteries is usually relatively constant for
most of the
time that such batteries are discharging into a load, the amount of power
delivered to the
LED 101 is essentially regulated regardless of the voltage drop of the LED 101
as long as
said voltage drop is high enough for the current flowing through the inductor
1103 to
decrease when the transistor 1102 is off.
[0189] The transistor 1102 in the currently favored embodiment of the present
invention
is a power MOSFET of the logic level variety that is designed for use with
supply
voltages around 5 volts and less than 10 volts. Non-logic level MOSFETs can be
used as
the transistor 102 if the power supply voltage is higher. In addition, the
transistor 1102
can be a bipolar type, possibly a Darlington type. Such bipolar types require
current input
rather than voltage input, but will work in the boost converter as long as the
pullup
resistor 1118 supplies sufficient current for a bipolar version of the
transistor 1102 to be
on and as long as the comparator 1101a, when low, has an output voltage with
respect to
ground to ensure that such a bipolar version of the transistor 1102 is off
[0190] A capacitor 1119 is provided in the preferred embodiment of the
invention to filter
or smooth the pulsating current that flows through the diode 1110 into a more
nearly
steady direct current flowing through the LED 101. Usually but not
necessarily, such
smoothing or filtering favorably affects the efficiency of the LED 101. It is
forseeable
that in alternative embodiments of the present invention, the capacitor 1119
is omitted,
CA 02615567 2007-12-19
especially should the LED 101 be of a type that has efficiency increased by
having a
pulsating current waveform with higher instantaneous current as opposed to a
steadier
. current having a lower peak instantaneous value.
[0191] With continuing reference to FIG. 11, additional comparators 1101b and
1101c
are employed in the boost converter circuit of the currently preferred
embodiment of the
present invention. These additional comparators are typically but not
necessarily
comprised in the same integrated circuit package as the comparator 1101a.
[0192] Preferably, the comparator 1101b is used to protect the boost converter
circuit
from ill effects of insufficient supply voltage and the comparator 1101c is
used to protect
the boost converter circuit from ill effects of excessive output voltage that
would result if
the LED 101 is disconnected or fails in a way where it becomes an open
circuit.
[0193] The comparator 1101b is low if it senses insufficient supply voltage.
The supply
voltage is divided to a lower voltage determined by the voltage divider
comprising the
resistors 1111 and 1112. A positive feedback resistor 1113 with a large value
is typically
but not necessarily employed to add hysteresis to the function of the
comparator 1101b
for stabilization purposes. Such a divided voltage derived from the point
where the
resistors 1111 and 1112 connect to each other is compared to the voltage
across the diode
1104. If the divided supply voltage presented to the non-inverting input of
the comparator
1101b is less than the voltage across the diode 1104, then the comparator
1101b is low
and prevents the transistor 1102 from being on. This can be desirable since
otherwise
with insufficient supply voltage the transistor 1102 can be only partially on
when it is
supposed to be on, and in such a case may be unable to pass the current it
should conduct
without an excessive voltage drop. Such an excessive voltage drop multiplied
by the
current conducted by the transistor 1102 may be an amount of power that
overheats the
transistor 1102 if the boost converter is not disabled by excessively low
supply voltage.
[0194] The comparator 1101c is used to detect excessive output voltage that
would
typically result from the LED 101 being disconnected or failing in a way where
it
41
CA 02615567 2007-12-19
becomes an open circuit. A voltage divider comprising two resistors 1114 and
1117 It is
easiest to combine the outputs of the comparators 1101b and 1101c with each
other and
the output of the comparator 1101a if the comparators are of the open
collector type. In
such a preferred case, the outputs of the comparators 1101a, 1101b, and 1101c
are
connected to each other and to the gate of the transistor 1102. In such a
case, it is
necessary in addition to have the pullup resistor 1118 so that the gate of the
transistor
1102 is high if all of the comparators used are high. The circuitry becomes
more
complicated if more than one comparator is employed and the comparators are
not of an
open collector or open drain type. Such more complicated circuitry would
typically
employ means to AND the outputs of comparators that are not of an open
collector or
open drain type. Such more complicated circuitry employed to utilize more than
one
comparator element of a type that is not open collector nor open drain shall
be considered
alternative embodiments of the boost converter provided by at least one aspect
of the
present invention.
[0195] Referring to FIG. 12, the boost converter circuit 1100 has additional
resistors
1122 and 1123. These additional resistors are employed to have the comparator
sense not
just the voltage across the current sensing resistor 1108 but a combination of
the supply
voltage and the voltage across the current sensing resistor 1108.
[0196] The purpose is to cause the essentially regulated current flowing
through the
current sensing resistor 1108 to decrease as the supply voltage increases, in
order to
accomplish having the power delivered to the LED 101 not increase roughly
proportionately with the supply voltage. As a result with appropriate values
for the
resistors 1122 and 1123, the power delivered to the LED 101 can be essentially
constant
with respect to varying power supply voltage as long as the power supply
voltage is
within a forseeable expected useful range.
[0197] Power supply connections to the comparators 1101a, 1101b and 1101c are
not
shown.
42
CA 02615567 2007-12-19
[0198] Referring to FIG. 13, the boost converter circuit 1100 can be modified
by having a
555 timer 1301 and an operational amplifier 1302 in lieu of the comparator
1101a. The
anode of the voltage reference diode 1104 is connected to the control voltage
pin of the
555 timer 1301. The trigger and threshold pins of the 555 timer 1301 are
connected
together, which makes the 555 timer a Schmidt trigger inverting buffer. The
voltage
across the current sense resistor 1108 is amplified by the operational
amplifier 1302 to an
extent determined by the feedback network comprising two resistors 1303 and
1304.
When the amplified voltage from the output of the operational amplifier 1302
is less than
half the voltage across the diode 1104, the 555 timer 1301 is high and turns
the transistor
1102 on. The 555 timer remains high until the voltage presented to its trigger
and
threshold pins exceeds that presented to its control voltage pin. When the
amplified
voltage from the output of the operational amplifier 1302 exceeds the voltage
across the
diode 1104, then the 555 timer 1301 switches to its low state and turns the
transistor 1102
off. The 555 timer 1301 returns to its high state when the voltage presented
to its trigger
and threshold pins by the operational amplifier 1302 decreases to half the
voltage
presented by the diode 1104 to the control voltage pin of the 555 timer 1301.
[0199] Otherwise, operation is like that of the boost converter circuit 1100
described in
FIGS. 2 and 3. Comparators or additional operational amplifiers used as
comparators may
be employed to function like the comparators 1101b and 1101c shown in FIGS. 2
and 3
to protect the transistor 1102 and the diode 1110 from excessive output
voltage and to
prevent the boost converter circuit 1100 from operating if the power supply
voltage is
insufficient.
[0200] Power supply connections to the 555 timer 1301 and the operational
amplifier
1302 are not shown. The reset pin of the 555 timer 1301 is normally connected
to the
positive power supply connection 1120, but may be connected otherwise so as to
be
essentially connected to the negative power supply connection 1121 instead as
a result of
additional circuitry detects insufficient supply voltage or excessive output
voltage. Such
additional circuitry would typically be similar to that comprising the
comparators 1101b
and 1101c shown in FIGS. 2 and 3. Such additional circuitry may use
comparators or
43
CA 02615567 2007-12-19
operational amplifiers. Such additional operational amplifiers may be but is
not
necessarily comprised in the same integrated circuit package as the
operational amplifier
1302.
[0201] Other timer integrated circuits similar to the 555 can be used in lieu
of a 555 for
the timer integrated circuit 1301. Other variations of the boost converter
circuit 1100 may
be developed, using integrated circuits other than comparators and timers that
resemble
the 555.
[0202] Referring to FIG. 14, a simpler and less efficient variation of the
boost converter
circuit 1100 can be used in the present invention. This simpler boost
converter circuit
1100 uses a 555 timer 1301 connected as an oscillator. The oscillator shown is
the
traditional astable 555 circuit and comprises the 555 timer 1301, resistors
1401 and 1402,
and a timing capacitor 1403. A first resistor 1401 is connected from the
positive power
connection 1120 to the discharge pin of the 555 timer 1301. A second resistor
1402 is
connected from the discharge pin of the 555 timer 1301 to the trigger and
threshold pins
of the 555 timer 1301. The trigger and threshold pins of the 555 timer are
connected to
each other. A timing capacitor 1403 is traditionally connected from the
trigger and
threshold pins of the 555 timer 1301 to the negative power supply connection
1121, but
could be connected to the positive power connection 1120 instead. Values of
the resistors
1401 and 1402 and the capacitor 1403 would be selected for the 555 timer 1301
to be
high and low for appropriate amounts of time. In this implementation of the
boost
converter circuit 1100, the 555 timer is normally high for a greater amount of
time than it
is low.
[0203] In an alternative implementation of the astable 555 oscillator, the
resistor 1401
can be omitted and the resistor 1402 can be connected from the trigger and
threshold pins
of the 555 timer 1301 to the output of the 555 timer 1301 instead of to the
discharge pin
of the 555 timer 1301.
[0204] No current sensing resistor is used.
44
CA 02615567 2007-12-19
[0205] A capacitor (not shown) may be connected from the control voltage pin
of the 555
timer 1301 to either the negative power supply connection 1121 or the positive
power
supply connection 1120. Said capacitor is not necessarily employed.
[0206] When the output of the 555 timer 1301 is high, the transistor is on and
essentially
connects the inductor 1103 across the power supply connections 1120 and 1121.
Current
flowing through the inductor increases. When the output of the 555 timer is
low, the
transistor is off and current flowing through the inductor 1103 flows through
the LED
101. Said current flowing through the LED 101 can be filtered or smoothed by
the
capacitor 1119.
[0207] Ideally, the 555 should be low long enough for the current flowing
through the
inductor 1103 to decrease to zero before the 555 becomes high again. Otherwise
the
current flowing through the inductor 1103 can increase to an excessive value.
It is
forseeable that further variations of this variation of the boost converter
circuit 1100 can
be made that operate satisfactorily if the current flowing through the
inductor 1103 does
not decrease to zero before the transistor 1102 is turned on to resume
increase of said
current flowing through the inductor 1103.
[0208] There are possible improvements to this variation of the boost
converter circuit
1100, such as having the negative leads of the LED 101 and the capacitor 1119
connected
to the negative power supply connection 1121 instead of the positive power
supply
connection 1120. This would have the power supply voltage assist current
flowing
through the LED 101 when the current flowing through the inductor 1103 is
forced
through the LED 101 by the transistor 101 being off If the voltage required to
operate the
LED 101 is less than twice the power supply voltage, then with this
improvement it will
typically be necessary to have the transistor 1102 off for a greater amount of
time than
the transistor 1102 is on. Although it is forseeable that off time
insufficiently long for the
current flowing through the inductor 1103 to decrease to zero, it is apparent
that it would
be preferable to shorten the on time, lengthen the off time or both if
necessary for the
CA 02615567 2007-12-19
current flowing through the inductor 1103 to decrease to zero while the
transistor 1102 is
off. This can be achieved by adding an inverting buffer between the output of
the 555
timer 1301 and the transistor 1102. Said inverting buffer can be achieved with
a second
555 timer. Said second 555 timer may be packaged with the 555 timer 1301 in a
single
integrated circuit package such as a 556. Timer integrated circuits other than
the 555 and
556 may be found to be usable.
[0209] An oscillator other than one based on a 555 timer can be used. Such
oscillators
include but are not limited to ones based on operational amplifiers, ones
based on
comparators, astable multivibrators, Schmidt trigger oscillators using a
device other than
a 555 timer as a Schmidt trigger, and function generator integrated circuits
used to
produce a square wave.
[0210] Referring to FIG. 15, an LED inspection lamp can have a switching
current
regulator circuit 1500 that enables the LEDs 401 to receive a quantity of
current that does
not vary significantly with the battery voltage, as long as the battery
voltage significantly
exceeds the minimum voltage required to cause the desired amount of current to
flow
through the LEDs 101. The shown switching regulator 1500 comprises a
comparator
1503, an inductor 1501, a switching transistor 1502, diodes 1505, 1514, and
1515,
resistors 1504, 1506, 1507, 1508, 1509, 1510 and 1511, and capacitors 1512 and
1517.
[0211] The comparator 1503 compares the voltage drops across two resistors
1507 and
1504. One lead of the resistor 1504 is connected to one lead of the resistor
1507, and this
enables comparing the voltages of the other leads of these two resistors with
respect to
ground or the negative battery terminal. Of these two resistors, the resistor
1504 is a
current sensing resistor that has a voltage drop that is nearly enough
proportional to the
magnitude of the current flowing through LEDs 401.
[0212] Assuming the power supply voltage exceeds the combined normal voltage
drops
of one of the LEDs 401 and the diode 1505, current will flow through the
resistor 1506.
The diode 1505 is used for a voltage reference and the resistor 1506 is
provided in order
46
CA 02615567 2007-12-19
for a small quantity of current to flow through the diode 1505. A voltage
divider
comprising the resistors 1507 and 1508 provides a divided reference voltage
that is
compared with the voltage across the current sensing resistor 1504.
[0213] The voltage divider resistors 1507 and 1508 should have sufficiently
high values
and the resistor 1506 should have a sufficiently low value such that most of
the current
flowing through the resistor 1506 flows through the diode 1505 rather than
through the
voltage divider resistors 1507 and 1508. This provides for a voltage across
the resistor
1507 being nearly constant, and equal to the voltage drop of the diode 1505
times the
value of the resistor 1507 divided by the sum of the values of the resistors
1507 and 1508.
[0214] When power is initially applied, the magnitude of the current flowing
through the
inductor 1501 and the current sensing resistor 1504 is zero. As a result, the
voltage across
the current sensing resistor 1504 is zero. However, voltage will appear
immediately
across the resistor 1507. This results in the inverting input of the
comparator 1503 being
more negative than the non-inverting input of the same comparator, and so the
output of
the same comparator will be "high" and turn "on" the switching transistor
1502.
[0215] The switching transistor as shown is a power MOSFET. Other transistor
types can
=
be used for the switching transistor 1502, including MOSFETs other than power
MOSFETs, insulated gate bipolar transistors, and conventional bipolar
transistors. If the
switching transistor 1502 is a conventional bipolar transistor and the
comparator 1503 is
not of an "open collector" or "open drain" type, then it is typically
necessary to add a
resistor (not shown) in series with the base terminal of a conventional
bipolar transistor
being used as the switching transistor 1502.
=
[0216] When the switching transistor 1502 is "on" or conductive, assuming the
power
supply voltage is sufficient, current will flow through through the LEDs 401,
the current
= sensing resistor 1504, the inductor 1501 and the switching transistor
1502. The current
will increase at a rate equal to the voltage across the inductor divided by
the value of the
inductor. The voltage across the inductoris the supply voltage minus the
voltage drops of
47
CA 02615567 2007-12-19
the LEDs 401 and other components that current flowing through the inductor
1501 has
to flow through, such as any protection diode 1515, current dividing resistors
1513, the
current sensing resistor 1504 and the switching transistor 1502.
[0217] The current flowing through the inductor 1501 increases and will
normally
increase to an extent such that the voltage drop of the current sensing
resistor 1504
exceeds the voltage across the resistor 1507.
[0218] When that happens, the output of the comparator 1503 will switch to its
"low"
state and turn "off' the switching transistor 1502.
[0219] When the switching transistor 1502 is "off' or nonconductive, current
that is
flowing through the inductor 1501 continues to flow and but does so through a
closed
loop comprising the inductor 1501, the current sensing resistor 1504, the LEDs
401 and a
diode 1514. With no power supply in this closed loop, the magnitude of this
current will
decrease. Once this current decreases to an extent such that the voltage drop
of the
current sensing resistor 1504 is less than the voltage across the resistor
1507, the output
of the comparator will go "high" again and the switching transistor 1502 will
be switched
"on" again. The magnitude of the current flowing through the current sensing
resistor will
alternately increase and decrease but will normally always be close to that
necessary to
cause the voltage drop of the current sensing resistor 1504 to be close to the
voltage
across the resistor 1507.
[0220] As a result, the magnitude of the current flowing through the current
sensing
resistor 1504, which is nearly all of the current flowing through the LEDs
401, is
essentially regulated.
[0221] Resistors 1509 and 1510 are provided to provide a small amount of
positive
feedback to the non-inverting input of the comparator 1503 from the output of
the same
comparator. This allows the magnitude of the current flowing through the
current sensing
resistor to change by some significant extent before the comparator 1503
changes states.
48
CA 02615567 2007-12-19
This is typically necessary for the switching transistor 1502 to spend nearly
all of the
time of each switching cycle being either fully conductive or fully
nonconductive.
[0222] When the switching transistor 1502 is "on" or conductive, nearly all of
the current
being consumed by the circuit 1500 from the battery 405 is flowing through the
LEDs
401. When the switching transistor 1502 is "off' or nonconductive, the current
flowing
through the LEDs 401 is not being drawn from the battery 405. At that time,
the only
current being drawn from the battery 405 is that necessary for the comparator
1503 to
function. As a result, the average current being drawn from the battery 405 is
normally
less than the current flowing through the LEDs 401. This is an advantage of a
switching
current regulator 1500 over "linear" or non-switching current regulator
circuits that would
normally result in current consumption from the battery 405 to be at least as
great as the
current flowing through the LEDs 401.
[0223] The switching regulator 1500 also comprises a pullup resistor 1511 if
the
comparator 1503 is an "open collector" or "open drain" type. A capacitor 1512
may be
provided across the power supply terminals of the comparator 1503 to absorb
any
switching-related transients in the supply voltage to the comparator 1503. A
filter
capacitor 1517 may be provided to make the magnitude of the current flowing
through
the LEDs 401 more constant throughout each cycle of the increase and decrease
of the
magnitude of the current flowing through the current sensing resistor 1504. A
diode 1515
may be provided to protect the circuit 1500 from being damaged should the
battery 405
be connected with reversed polarity. Such a diode 1515 may be a Schottky diode
since
Schottky diodes have a lower voltage drop than most other diodes do. A fuse
1516 may
be provided to prevent catastrophic failure should the circuit 1500
malfunction. A switch
407 is typically provided to turn on and off the circuit 1500. Current
dividing resistors
1513 may be necessary if more than one LED 401 is used and the LEDs 401 are to
be
connected essentially in parallel with each other.
[0224] An inspection lamp having the shown components of the switching current
regulator circuit 1500 may have additional components (not shown) including
but not
49
CA 02615567 2007-12-19
limited to a battery status indicator lamp. Such a battery status indicator
lamp may be
controlled by a voltage comparator circuit that uses a comparator in the same
integrated
circuit package as the comparator 1503.
[0225] Referring to FIG. 16, an LED inspection lamp can have a boost converter
circuit
1600 that is suitable for LED flashlights and LED inspection lamps having an
LED 401
or series string of LEDs 401 requiring a greater voltage than is available
without a boost
converter.
[0226] The boost converter can be a current-regulating boost converter. The
circuit of
FIG. 16 is such a current-regulating boost converter, found to adequately
deliver
regulated current through a series string of LEDs 401 when the supply voltage
is =
anywhere from 4.5 to 10 volts.
[0227] The current regulating boost converter 1600 shown in FIG. 16 has an
integrated
circuit 1601 that is of a type suitable for such purposes in LED flashlights,
and said
integrated circuit 1601 may be but is not necessarily a "PJ34063CS" type.
[0228] A boost converter circuit 1600 typically requires an inductor 1603. The
value of
the inductor 1603 is typically but not necessarily 47 to 100 microhenries. The
inductor
1603 has a requirement of not saturating at the peak current that it is
required to conduct,
which is typically but not necessarily approaching twice the ratio of total
LED power to
the voltage drop across the LED or series string thereof 401. A suitable
inductor 1603
typically has a ferrite core that is gapped or is made of a low permeability
material in
order to minimize the overall size of a core that does not saturate. The core
material is
typically nonconductive in order to minimize eddy current losses in the core.
An inductor
1603 having a rod style core will work but generally the inductor can be made
smaller
with a gapped core than with a rod style core.
[0229] A battery 405 is shown, which is of a "9 volt alkaline" "transistor
radio" type,
although other types including rechargeable types could be used in alternative
CA 02615567 2007-12-19
embodiments of the present invention.
[0230] A switch 407 is provided to turn on/off the circuit 1600. Preferably
the switch 407
is a pushbutton type that is usable both as a momentary switch (by pushing
"halfway
down") and as an "on/off' switch by pushing with greater force.
[0231] A current sensing resistor 1604 is provided for sensing the magnitude
of the
current that is flowing through the LEDs 401. An operational amplifier 1602
and
associated gain-determining resistors 1605 and 1606 are provided to supply to
the
integrated circuit 1601 a feedback of the magnitude of the current that is
flowing through
the LEDs 401 and the current sensing resistor 1604. The resistor 1607, having
a value
close to that which would be achieved by paralleling the resistors 1605 and
1606, is
provided so that the two inputs of the operational amplifier 1602 receive as
equally as
possible any effects of the input currents produced by the operational
amplifier 1602. A
capacitor 1608 is provided for filtering that the integrated circuit 1601 may
require of the
feedback signal. It is foreseeable that the circuit 1600 may be made to work
satisfactorily
without the resistor 1607 and the capacitor 1608.
[0232] The operational amplifier 1602b and its associated circuitry form an
amplifier that
amplifies the voltage across the current sensing resistor 1604. When the
output voltage of
the operational amplifier 1602b exceeds approx. 1.6 volts, the integrated
circuit 1601
shuts down until the output voltage of the operational amplifier 1602b
decreases slightly.
[0233] The integrated circuit 1601 includes a switching transistor. The
collector lead of
the switching transistor is connected to a collector lead 1611 of the
integrated circuit
1601. The collector lead 1611 is connected to one lead of the inductor 1603,
while the
other lead of the inductor 1603 is connected to the main positive power supply
point 1612
of the circuit 1600. Pulsating direct current at a voltage higher than that of
the voltage of
the battery 405 is achieved from the switching transistor repeatedly
interrupting the
current that is flowing through the inductor 1603. This pulsating higher
voltage is
received from the collector lead 1611 and filtered into steady direct current
by a diode
51
CA 02615567 2007-12-19
1609 and a filter capacitor 1610. The diode 1609 is required tci keep the
capacitor 1610
from discharging through the integrated circuit 1601 when the switching
transistor inside
the integrated circuit 1601 is on. The diode 1609 should be of a type that is
suitable for
the ultrasonic frequency of the pulsating direct current that is received from
the collector
lead 1611. The diode 1609 may be a Schottky diode.
[0234] In variations of the boost converter circuit 1600, the switching
transistor can be a
separate part (not shown) rather than a part of the integrated circuit 1601.
The switching
transistor, whether it is a separate part or a part of the integrated circuit
1601, may be a
MOSFET. If the switching transistor is a MOSFET, then the transistor terminal
that is
connected to the inductor 1603 is referred to as a "drain" rather than as a
"collector".
[0235] A resistor 1613 and capacitor 1614 are external parts that are required
associated
components of the circuitry inside the integrated circuit 1601. A capacitor
1615 in
parallel with the series string of LEDs 301 is a low value capacitor that has
been found to
be beneficial for optimum operation of the circuit 1600, apparently by
partially filtering
the higher frequency harmonic content of the pulsating direct current received
from the
collector terminal 1611. The larger value filtering capacitor 1610 can have
excessive
inductance for filtering the highest frequencies that are present to a
significant extent in
said pulsating direct current.
[0236] A diode 1616 is provided to protect the circuit 1600 in case the
battery 405 is
connected with reversed polarity. It is preferred that the diode 1616 be a
Schottky diode
because Schottky diodes have a lower voltage drop than other commonly
available
diodes.
[0237] A capacitor 1617 is provided across the power supply rails of the
circuit 1600 to
reduce irregularities in the supply voltage that result from non-constant
current draw
through the impedance of the battery 405.
[0238] The boost converter circuit may be assembled on a circuit board that
has
52
CA 02615567 2007-12-19
additional circuitry. Such additional circuitry may include circuitry that
controls a battery
status indicator lamp.
[0239] Referring to FIG. 17, a tenth embodiment is an inspection lamp 1700
that has one
or more LEDs 1701 that produce a beam of radiation that is suitable for
causing
fluorescence of materials to be detected by an inspection lamp, wherein the
LEDs 1701
produce a beam that has a width of 10 degrees or less. This would typically be
accomplished by making the LEDs 1701 of a narrow beam design and with a
diameter of
at least 7 millimeters. LEDs 1701 that have a diameter of 7.5 to 13
millimeters can easily
produce a beam that is sufficiently narrow and intense.
[0240] The LEDs 1701 would typically produce radiation that has a peak
wavelength of
395 to 415 nanometers in order to produce a beam that visibly illuminates the
area being
irradiated but is not so brightly visible as to overwhelm the visible
fluorescence of
fluorescent materials to be detected by using the inspection lamp 1700. The
LEDs 1701
may alternatively have a shorter peak wavelength but produce an adequately
visible beam
due to having a peak wavelength only slightly less than 395 nanometers or by
producing
some visible light that is outside the wavelength range of an essentially
visible main
spectral band in the ultraviolet. Ultraviolet LEDs with typical peak
wavelengths as short
as 365 nm usually produce some radiation that is visible. Further
alternatively, one or
more of the LEDs 1701 may produce a visible beam while at least one other of
the LEDs
1701 would produce essentially invisible radiation. The inspection lamp 1700
can also be
made with LEDs 1701 that have a peak wavelength longer than 415 nanometers,
although
wavelengths longer than 415 nanometers but capable of causing fluorescence of
visibly
fluorescent materials will typically require a user of the inspection lamp
1700 to use a
viewing filter such as tinted glasses that block most of the visible light
produced by the
inspection lamp 1700 but pass at least some of the light produced by
fluorescent materials
to be detected by using such an inspection lamp 1700.
[0241] The inspection lamp 1700 typically comprises additional parts such as
an outer
casing 1702, one or more batteries 1703, a switch 1704, a circuit board 1706,
current
53
CA 02615567 2007-12-19
-
limiting circuitry 1707, one or more wires 1708 connected to the switch 1704,
and one or
more wires or other pieces of conductive material 1709 for connecting to the
one or more
batteries 1703. A spring 1710 may be provided for making contact with any of
the one or
more batteries 1703. The outer casing 1702 may have a closed loop formation
1711 to
attach a lanyard to. Other arrangements for the inspection lamp 1700 are
foreseeable.
[0242] A front lens 1705 may be provided in the inspection lamp 1700 for
purposes
including any or any combination of the following purposes:
[0243] 1. As part of making the inspection lamp 1700 waterproof.
[0244] 2. To make the inspection lamp 1700 more attractive. For such a
purpose, the lens
1700 may be a non-planar lens such as a convex or concave lens or a fresnel
lens with a
long focal length. Such a lens may comprise more than one lens element. Such a
lens may
have prismatic facets. If the lens 1705 has prismatic facets, then the LEDs
1701 would be
aimed in directions such that their beams are projected into a desirable
direction upon
exiting the lens 1705. Any facets in the lens 1705 may be convex or concave in
addition
to being prismatic.
[0245] 3. To diffuse the beam to a small extent to remove sharp irregularities
in the beam.
Such a diffusing lens may be textured, translucent and/or frosted.
[0246] 4. As a filter that blocks undesirable wavelengths of radiation
produced by the
LEDs 1701, such as light that has wavelengths the same as or near the
wavelengths of
radiation produced by fluorescent materials to be detected by using the
inspection lamp
1700.
[0247] If a lens 1705 is used and it is not planar, the lens 1705 or
individual lens elements
in the lens 1705 may be biconvex, planoconvex, concavo-convex, biconcave,
planoconcave, or convexconcave. Any curved surfaces of the lens 1705 may be
spherical,
compound curves, or aspheric curves such as paraboloidal curves or ellipsoidal
curves.
54
CA 02615567 2007-12-19
[0248] The current limiting circuitry 1707 is typically necessary for proper
operation of
the ultraviolet LEDs 1701. The current limiting circuitry 1707 may be one or
more
resistors, one or more linear current regulator, one or more switching current
regulators,
or one or more boost converters. If a boost converter or other circuit
depending on
switching of inductors or capacitors is used, typically but not necessarily
only one circuit
is used no matter how many ultraviolet LEDs 1701 are provided. The one or more
t
sources 1701 may or may not receive power from the current limiting circuitry
1707 that
the ultraviolet LEDs 1701 receive power from. Separate circuitry may be used
to limit the
current that flows through the one or more visible light sources 1701.
[0249] Referring to FIG. 18, an eleventh embodiment is an inspection lamp 1800
comprising two or more LEDs 1801 that are aimed rearward towards concave
mirrors
1802 so that the concave mirrors 1802 collimate the radiation produced by the
LEDs
1801 into a beam. Typically each of the LEDs 1801 is associated with a
corresponding
concave mirror 1802, and the number of concave mirrors 1802 would typically be
the
same as the number of LEDs 1801. Alternatively, it is foreseeable that an
inspection lamp
1801 could be made to work with the number of concave mirrors 1802 being
different
from the number of LEDs 1801.
[0250] The concave mirrors 1802 are ideally ellipsoidal if they are to produce
a beam that
is well defined at short distances forward of the inspection lamp 1800. The
concave
mirrors 1802 are ideally paraboloidal if they are to produce a beam that is
well defined at
great distances forward of the inspection lamp 1800. Other shapes of curved
surfaces of
the concave mirrors 1802 may be found to work adequately, such as
hyperboloidal or
spherical shapes. The concave mirrors may have stepped surfaces like those of
fresnel
lenses. The concave mirrors 1802 may or may not comprise a plurality of flat
facets. The
concave mirrors 1802 may or may not be textured for purposes such as smoothing
irregularities in the beams formed by them or for an attractive appearance.
[0251] The concave mirrors 1802 may or may not have a protective overcoating.
If any
CA 02615567 2007-12-19
concave mirror elements 802 have a protective overcoating, the protective
overcoating
may be silicon dioxide. Any protective overcoating on any concave minors 1802
may be
a polymer. Any protective overcoating on any concave mirrors 1802 may be
sprayed on
or applied in a manner other than spraying, such as being applied with a
paintbrush or
similar means. Any protective coating may or may not require curing or
solidification
such as by evaporation of a solvent, inherent reaction of chemical ingredients
in the
protective coating, or oxidation or polymerization. Curing of any protective
coating on
any minors 1802 may or may not require or be assisted by irradation by
ultraviolet
radiation or other radiation. Any minors 1802 may or may not require elevated
temperatures in their formation, such as for curing of any protective coating.
[0252] The LEDs 1801 would typically produce radiation that has a peak
wavelength of
395 to 415 nanometers in order to produce a beam that visibly illuminates the
area being
irradiated but is not so brightly visible as to overwhelm the visible
fluorescence of
fluorescent materials to be detected by using the inspection lamp 1800. The
LEDs 1801
may alternatively have a shorter peak wavelength but produce an adequately
visible beam
due to having a peak wavelength only slightly less than 395 nanometers or by
producing
some visible light that is outside the wavelength range of an essentially
visible main
spectral band in the ultraviolet. Ultraviolet LEDs with typical peak
wavelengths as short
as 365 nm usually produce some radiation that is visible. Further
alternatively, one or
more of the LEDs 1801 may produce a visible beam while at least one other of
the LEDs
1801 would produce essentially invisible radiation. The inspection lamp 1800
can also be
made with LEDs 1801 that have a peak wavelength longer than 415 nanometers,
although
wavelengths longer than 415 nanometers but capable of causing fluorescence of
visibly
fluorescent materials will typically require a user of the inspection lamp
1800 to use a
viewing filter such as tinted glasses that block most of the visible light
produced by the
inspection lamp 1800 but pass at least some of the light produced by
fluorescent materials
to be detected by using such an inspection lamp 1800.
[0253] A front lens 1804 may be provided in the inspection lamp 1800 for
purposes
including any or any combination of the following purposes:
56
CA 02615567 2007-12-19
[0254] 1. As part of making the inspection lamp 1800 waterproof.
[0255] 2. To make the inspection lamp 1800 more attractive. For such a
purpose, the lens
1800 may be a non-planar lens such as a convex or concave lens or a fresnel
lens with a
long focal length. Such a lens may comprise more than one lens element. Such a
lens may
have prismatic facets. If the lens 1804 has prismatic facets, then the concave
mirrors 1802
would be aligned in a manner such that the beams formed by the concave mirrors
1802
are projected into a desirable direction upon exiting the lens 1804. Any facts
in the lens
1804 may be convex or concave in addition to being prismatic.
[0256] 3. To diffuse the beam to a small extent to remove sharp irregularities
in the beam.
Such a diffusing lens may be textured, translucent and/or frosted.
[0257] 4. As a filter that blocks undesirable wavelengths of radiation
produced by the
LEDs 1701, such as light that has wavelengths the same as or near the
wavelengths of
radiation produced by fluorescent materials to be detected by using the
inspection lamp
1800.
[0258] If a lens 1804 is used and it is not planar, the lens 1804 or
individual lens elements
in the lens 1804 may be biconvex, planoconvex, concavo-convex, biconcave,
planoconcave, or convexconcave. Any curved surfaces of the lens 1804 may be
spherical,
compound curves, or aspheric curves such as paraboloidal curves or ellipsoidal
curves.
[0259] The LEDs 1802 may be attached to an LED board 1803. The LED board 1803
may be a circuit board, a circuit board combined with a heatsink, or it may
comprise a
piece of material suitable for use as a heatsink.
[0260] The inspection lamp 1800 typically has an outer casing 1806 that
typically has a
distinct head section and handle section. As shown, the head section and
handle section
of the outer casing 1806 have a common longitudinal axis. Alternatively, the
inspection
57
CA 02615567 2007-12-19
lamp may have a head and handle with axes that are offset from each other or
not parallel
to each other. For example, a variation of the inspection lamp 1800 or of
other inspection
lamps shown herein may have a handle in the form of a pistol grip.
[0261] The LED board 1803 may, as shown, be attached to the front lens 1804
with glue
1805. Alternative means of mounting the LED board 1803 are foreseeable, such
as
connecting it to the outer casing 1806 with thin rods (not shown).
[0262] A circuit board 1807 is typically provided. The LEDs 1801 typically
require
current limiting circuitry 1808 that is mounted on the circuit board 1807. The
current
limiting circuitry 1808 is typically necessary for proper operation of the
LEDs 1801. The
current limiting circuitry 1808 may be one or more resistors, one or more
linear current
regulator, one or more switching current regulators, or one or more boost
converters. If a
boost converter or other circuit depending on switching of inductors or
capacitors is used,
typically but not necessarily only one circuit is used no matter how many LEDs
1801 are
provided. The one or more LEDs 1801 may or may not receive power from the
current
limiting circuitry 1808 that the LEDs 1801 receive power from. Separate
circuitry may be
used to limit the current that flows through the one or more visible light
sources 1801.
[0263] The concave mirrors 1802 may be attached to the circuit board 1807 by
means of
glue 1809. If the concave mirrors 1802 are attached to the circuit board 1807,
either the
concave mirrors 1802 or the circuit board 1807 may be mounted to the outer
casing 1806.
Other arrangements are foreseeable for holding the circuit board 1807 and the
concave
mirrors 1808 in their proper positions.
[0264] Wires 1810 are typically provided to supply power to the LEDs 1801. The
wires
1810 may be comprised in a cable 1811.
[0265] The inspection lamp 1800 is typically powered by one or more batteries
1812,
although alternatively the inspection lamp 1800 may receive power from an
external
power source. Any batteries 1812 may or may not be rechargeable.
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CA 02615567 2007-12-19
[0266] The inspection lamp 1800 is shown with a switch 1813, a battery spring
1814,
wires 1815, and a closed loop 1816 to attach a lanyard to. As shown, the
circuit board
1807 may have a battery contact 1817. Other arrangements are foreseeable for
alternative
embodiments of an inspection lamp having two or more LEDs 1801 and associated
concave mirrors 1802.
[0267] Referring to FIG. 19, a twelfth is an inspection lamp 1900 comprising a
head 1901
and a handle 1902 connected together by a flexible member 1903. Disposed
within the
head 1901 is at least one LED 1904. A reflector 1905 and/or a lens 1906 may be
but are
not necessarily provided for collimating the radiation produced by the LED
1904 into a
beam. The LED receives power via wires 1908, although if the flexible member
1903 is
conductive it may be used in lieu of one of the wires 1908.
[0268] The LED 1904 is preferably a high power type that requires or benefits
from
heatsinking. Heatsinking may be provided by any combination of the head 1901,
flexible
member 1902 and either or both of the wires 1908. One or more additional wires
(not
shown) may be provided to conduct heat from the LED 1904 without supplying
power to
it.
[0269] The LED 1904 may be attached to a cap 1907 that has one or more holes
1916
that any of the wires 1908 can pass through. Alternative arrangements are
possible, such
as mounting the LED 1904 directly to the head 1901. ,
[0270] The LED 1904 preferably has a peak wavelength of 395 to 415 nanometers,
so
that its radiation is sufficiently visible to visibly illuminate the area
being irradiated, but
not so visible as to overwhelm the light produced by fluorescent materials to
be detected
by using the inspection lamp 1900. Alternatively, the LED 1900 can have a
shorter peak
wavelength since most ultraviolet LEDs produce some visible light. Such a
shorter
wavelength model of the LED 1904 may have a peak wavelength in the 380 to 395
nanometer range and have some of its main emission band slightly visible, or
it may have
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CA 02615567 2007-12-19
the long wavelength "tail" of of its main emission band being adequately
visible, or it -
may have visible out-of-band content, or it may contain or have added to it
fluorescent
material for producing a small amount of visible light. Fluorescent material
for producing
a small amount of visible light to illuminate the area being irradiated, if
used, may be
placed anywhere in the head 1904.
[0271] Further alternatively, the radiation produced by the inspection lamp
1900 may be
essentially invisible, or it may be so visible that viewing glasses or a
viewing filter that
blocks most of this radiation would be necessary in order to see the
fluorescence of
fluorescent materials to be detected by using the inspection lamp 1900.
[0272] A reflector 1905 may be provided in the head 1901 for purposes such as
collimating light from the LED 1904 into a beam. A front lens 1906 is
typically but not
necessarily provided for any combination of purposes such as filtering the
radiation
produced by the LED 1904, collimating the radiation from the LED 1904 into a
beam, or
protecting the LED 1904 or other parts from water, dirt, dust, or impact by
foreign
objects. Any reflector 1905 is typically but not necessarily of a concave
shape such as
paraboloidal or ellipsoidal, but may be spherical, conical, of another shape,
or of a
combination of shapes or comprise zones of different shapes. Any reflector
1905 may be
faceted or textured. Any lens 1906 may be planar, biconvex, planoconvex,
concavoconvex, biconcave, planoconcave, convexoconcave, a combination of zones
of
different shapes, or a fresnel version of any of these shapes. Any curvature
used on a
front lens 1906 may be spherical shape or an aspheric shape such as
paraboloidal,
hyperboloidal, or ellipsoidal or a different aspheric shape. Any lens 1906 may
be
translucent, frosted or textured if diffusing properties are desired for any
purpose such as
smoothing irregularities in the beam of radiation projected forwards from the
head 1901.
Any lens 1906 may have filtering characteristics.
[0273] The handle 1902 is shown as being in the shape of a pistol grip, but it
may be
cylindrical or of any other shape.
CA 02615567 2007-12-19
[0274] An LED inspection lamp typically requires current limiting circuitry
1909 for the
at least one LED 1904 to operate properly. The circuitry 1909 may comprise one
or more
resistors, one or more linear regulators, one or more switching regulators,
one or more
boost converters, or one or more current regulating boost converters.
Typically but not
necessarily no more than one regulating circuit or boost converter is used.
[0275] The current limiting circuit 1909 is shown in the handle 1902 but
alternatively it
may be located anywhere in or on the inspection lamp 1900.
[0276] The inspection lamp 1900 typically but not necessarily has one or more
batteries
1910.
[0277] The inspection lamp 1900 typically has a switch 1911. The switch 1911
may have
wires 1912 connected to it, or it may be combined with the circuitry 1909 into
a single
assembly. Other arrangements are possible.
[0278] The inspection lamp 1900 may, as shown, have a battery spring contact
1913 and
a wire 1914 or other conductor connected to the battery spring contact 1913.
As shown,
the current limiting circuit 1909 may be comprised in a module having a
battery contact
1915. Other arrangements are possible.
[0279] Referring to FIG. 20, a thirteenth embodiment is a handheld LED
spotlight 2100
for use in applications for intense illumination of a relatively small area
eat a distance
many times the focal length of the spotlight and beyond, such as for boating,
for the
theatre, or from an automobile. The small area is relative to the distance.
The LED
spotlight 2100 has a housing 2101, part of which is a handle 106 shown as
protruding
from the side of the main body of the housing 2101. The particular style shown
for the
housing 2101 has been used in existing halogen handheld spotlights used
commonly for
such activities as boating or from a vehicle.
[0280] The LED spotlight 2101 has an LED 2103 and a reflector 2102 to
collimate light
from the LED 2103 into a beam. In the configuration that is shown, the LED
2103 is
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CA 02615567 2007-12-19
preferably one with a nominally lambertian radiation pattern and the reflector
2102 is
preferably parabolic. The LED 2103 is aimed at the same direction that the
beam formed
by the reflector 2102 is projected, with the LED 2103 and the reflector 2102
preferably
having a common optical axis 2113.
[0281] The handle 2106 is preferably at an angle to the axis 2113 in a pistol
grip fashion
similar to that in halogen spotlights and electric drills. Alternatively, the
handle 2106
may be at a different angle to the axis 2113, such as being perpendicular to
the axis 2113.
The handle 2113 may be bent or in a loop form to allow one or both of its ends
to be
attached to the housing 2101 while the part of the handle 2113 to be handheld
is
essentially parallel to the axis 2113 or otherwise essentially parallel to a
nearby tangent
on the main body of the housing 2101. The handle 2106 and the housing 2101 may
be
distinct parts to be attached to each other or they may be distinct regions of
a single part
or distinct regions of a pair of parts to be attached to each other, such as
molded plastic
parts to comprise both the housing 2101 and the handle 2106.
[0282] LED spotlights may vary from the LED spotlight 2100 by having more than
one
handle or by having no distinct handles at all. Regardless of the number of
handles, an
LED spotlight may benefit from having provisions to mount onto a stand such as
a tripod,
or onto a vehicle such as a police car or other emergency vehicle.
[0283] For a balance of overall size and reflected intensity, as discussed
below, the
reflector 2102 is preferably 4.5 to 7 inches in diameter; howeverõ the
reflector 2102 may
be as small as 3 inches in diameter and as large as 9 inches in diameter or
more.
Halogen handheld spotlights for distance applications in general illumination
exist with a
reflector approximately 3.1 inches in diameter. Accordingly, LED spotlights in
accordance with the principals described herein having a similar diameter will
be useful
in some applications. Similarly, Halogen handheld spotlights for distance
applications in
general illumination exist with a reflector approximately 9 inches in
diameter.
Accordingly, LED spotlights in accordance with the principals described herein
having a
similar diameter or larger will be useful in some applications. It is expected
that
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reflectors as large as 10 to 12 inches in diameter will be found useful in
some
applications.
[0284] The reflector 2102 is preferably paraboloidal. Alternative shapes for
the reflector
2102 are possible, such as an ellipsoidal shape that may be preferred should
the LED
spotlight 2100 be intended for optimum performance at shorter distances.
[0285] The reflector 2102 preferably has a large ratio of depth to diameter to
reflect and
collimate into a beam a large percentage of the light produced by the LED
2103. The
reflector 2102 is shown as having a depth slightly less than its diameter,
such as is known
with LED flashlights having such an optical arrangement. It is possible for
the depth of
the reflector 2102 to equal or exceed its diameter.
[0286] The central region of the reflector 2102 has a central hole to
accommodate the
LED 2103 which is preferably located at the focal point of the reflector 2102.
The
central hole is shown as extending to the inside edge of the optically useful
reflective
surface of the reflector 2102. Alternative arrangements are possible, such as
a central
hole smaller than the inside diameter of the optically useful reflective
surface. If the
reflector 2102 has a central hole that is smaller than the inside diameter of
the useful
reflective surface, then the portion of the reflector that is within the
inside diameter of the
useful reflective surface may not follow the curve of the optically useful
portion. Such a
region of the reflector 2102 within the inside diameter of its optically
useful portion may
be flat and perpendicular to the optical axis 2113.
[0287] The useful reflective surface of the reflector 2102 has a frontal area
that is 1/4
times pi times the difference of the squares of the outside diameter and the
inside
diameter of the optically useful reflective surface. The intensity of the beam
formed by
the reflector 2102 is limited to this frontal area times the luminance of the
light emitting
surface of the LED 2103.
[0288] The LED spotlight 2100 preferably has one LED 2103 and one reflector
2102.
Alternatively, more than one reflector may be used, with each reflector having
an
associated LED. If more than one reflector is used, the plurality of
reflectors may
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CA 02615567 2007-12-19
comprise reflector elements that are merged together into one piece. If more
than one
reflector is used, then the reflectors may be partial circles in shape when
viewed from the
front, so that they can be merged together or fitted close to each other in a
space saving
manner.
[0289] If a variant of the LED spotlight 2100 has more than one reflector 2102
and
associated LED 2103, then the combinations of reflectors 2103 and associated
LEDs
2102 may have their optical axes converge at a finite distance forward of such
a variant
of the LED spotlight 2100, as is described above and shown as being done in
the LED
inspection lamp 800 of FIG. 8.
[0290] Use of combinations of optics and associated LEDs to produce beams that
may
merge together is also described above as being done in the LED inspection
lamp 400 of
FIG. 4, wherein the optics are lenses. It is also described above that the LED
inspection
lamp 400 or any other embodiment described herein may have LEDs that produce
wavelengths suitable for causing fluorescence of fluorescent materials, LEDs
that
produce any other wavelength desired for any specific application, or may have
white
LEDs.
[0291] The LED 2103 is preferably a high power LED that typically requires
heatsinking.
The LED 2103 may be one such as those sold by Cree under the trademark Xlamp
or
such as those sold by Lumileds under the trademark Luxeon.
[0292] The LED 2103 is preferably a single chip type such as Cree "Xlamp"
types or
Lumileds "Luxeon" types other than "Luxeon V". Multichip LEDs such as Lumileds
"Luxeon V" and Citizen Electronics CL-652 types can be used, but these have a
larger
light source area and will result in a wider and less intense beam. Use of a
multichip
form of the LED 2103 may result in a larger diameter of the reflector 2102
being
preferable, such as 6 or more inches in diameter.
[0293] The LED 2103 is preferably one having a nominally lambertian radiation
pattern,
since such LEDs have high luminance and favor intense beams despite a
significant
fraction of their light output not being utilized by the reflector 2102.
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CA 02615567 2007-12-19
[0294] Alternatively, the LED 2103 may be of a type that has radiation-output
mainly
into directions closer to perpendicular to its axis, such as the LED 101 in
the LED
inspection lamp 100 shown in FIG. 1. Any "side emitting" LED used in the LED
spotlight 2100 may be one such as those provided by Lumileds under the
trademark
Luxeon Side Emitter.
[0295] These "side emitting" LEDs have the disadvantage of lower luminance and
weaker beam intensity or alternatively often a less-neatly-defined beam, while
"side
emitting" LEDs have an advantage of a higher percentage of their light output
being
reflected by the reflector 2102 into a beam. An LED spotlight 2100 having a
"side
emitting" type of LED 2103 in lieu of a lambertian type of LED 2103 would
typically
have a beam that is wider but less intense and probably less neatly defined
than a beam
that can be achieved if the LED 2103 is a lambertian type.
[0296] Further alternatively, it is possible for the LED 2103 to have a
different radiation
pattern, such as batwing type sold by Lumileds under the trademark Luxeon
Batwing.
This radiation pattern was named for the shape of its spatial radiation graph.
This
radiation pattern approximates reciprocal cosine cubed over a limited range of
angles
from axis, and is designed to evenly illuminate an associated area of a flat
surface. This
radiation pattern has a disadvantage of directing much light only towards the
outer region
of the curved reflective surface of the reflector 2102 rather than all of the
curved
reflective surface of the reflector 2102.
[0297] The LED spotlight 2100 would typically be intended to produce white
light and
therefore the LED 2103 would typically be a white LED. Alternatively, an LED
spotlight
2100 may be intended for a specialized purpose that is better served by
colored light, and
accordingly the LED 2103 may be one that specializes in producing light of
such a
suitable color. For example, the LED 2103 may be a yellow LED to produce light
that is
less visibly reflected by fog so that objects illuminated by the LED spotlight
2100 are
easier to see through fog. Further alternatively, the LED 2103 may, like the
LED 101 in
the inspection lamp 100, be a type that produces radiation that is suitable
for causing
fluorescence of materials to be detected. Such a version of the LED 2301 may
produce
CA 02615567 2007-12-19
ultraviolet radiation, violet light, or blue light. In such a case, the LED
2301 may have a
nominal peak wavelength anywhere from 365 to 470 nanometers, and may have a
peak
wavelength of 450 nanometers, as is described above as being a possible peak
wavelength of the LED 501 in the inspection lamp 500 of FIG. 5.
[0298] The LED 2103 is shown as being mounted on a heatsink 2104. The heatsink
2104
may be a metal core printed circuit board, a piece of sheet metal or plate
metal, or a
heatsink of a non-planar shape such as one having protrusions such as fins.
The heatsink
2104 may be made into a non-planar shape by extrusion, die casting or
machining. The
heatsink 2104 is preferably made of a metal having high heat conductivity,
such as
aluminum or zinc or copper or an alloy of any of these metals.
[0299] Forward of the reflector 2102 is a lens 2114 is preferably provided to
protect the
reflector 2102 and the LED 2103 from breakage, scratches, and contamination by
dirt,
dust and liquids. The lens 2114 is preferably planar. Alternatively, a non-
planar form of
the lens 2114 may be used, for example to achieve a desired appearance. A non-
planar
lens may have a specific optical effect, such as being a convex lens that adds
convergence
to the beam formed by the reflector 2102. If this is done then preferably the
reflector
2102 forms a beam of such characteristics that the beam approximates being
ideally
collimated after being affected by any non-planar lens 2114. For example, the
LED 2103
may be centered slightly rearward of the focal point of the reflector 2102 if
the lens 2114
is a convex lens.
[0300] The lens 2114 is preferably made of a suitably tough transparent
material such as
polycarbonate. Alternative transparent materials such as acrylic or a suitable
grade of
glass may be used for the lens 2114.
[0301] The heatsink 2104 is shown as being planar and being held by ribs 2105
that are
part of the housing 2101. Alternative arrangements are possible, such as
gluing or
bolting the heatsink 2104 to the housing 2101. If the LED 2103 is an
especially high
power model, then part or all of the housing 2101 may be metal, and the
heatsink 2104
would be attached to or in close proximity to such metal housing material, so
that such
metal housing material can serve as an extension of the heatsink 2104.
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[0302] The LED spotlight is shown as having a switch 2107, a battery 2108 and
circuitry
2109 typically required for proper operation of LEDs. The switch 2107 is shown
as
being in the trigger position of a pistol grip, although any switch 2107 can
be anywhere
on the LED spotlight 2100 or even external to the LED spotlight 2100.
[0303] The battery 2108 is preferably a rechargeable type such as lead acid,
nickel
cadmium, nickel metal hydride, lithium ion, or lithium polymer. Alternatively
the battery
2108 may be a non-rechargeable type. The battery 2108 preferably comprises
more than
one cell. If the battery 2108 is replaceable, individual cells of the battery
2108 may be
replaceable. Further altenatively, the LED spotlight 2100 may operate from an
external
power source such as automotive power or an external battery, or may operate
from
either external power or a battery. If the LED spotlight 2100 is to be powered
by
automotive power, it may have a "cigarette lighter plug" or it may have wires
with clips
suitable to clip onto a vehicle's battery.
[0304] The circuitry 2109 is shown as having two input connection points and
two output
connection points, although the number of connection points can be different
and this can
change the wiring scheme. For, example, the circuitry 2109 may be a single
resistor,
which has only two leads. The circuitry 2109 may be a linear current
regulator, a
switching current regulator, or a boost converter with suitable current
limiting, current
regulating, or power regulating or otherwise suitable characteristics for
powering the
LED 2103.
[0305] Referring to FIG. 21, an LED spotlight 2200 can also be made where an
LED
2203 is directed rearwards towards a shallower concave reflector 2202 that
reflects the
light forward while collimating the light into a beam, as is done in the LED
inspection
lamp 200 of FIG. 2 and described above using the LED 201 and the concave
mirror 202.
The spotlight 2200 is for similar applications to the spotlight 2100 and
similar design
considerations are utilized with similar reflector sizes. The reflector 2202
is preferably
parabolic, but can be ellipsoidal if the LED spotlight 2202 is designed for
optimization of
concentrating light into a spot at a finite distance forward of the LED
spotlight 2200. The
concave reflector 2202 is larger than the concave mirror 202 in FIG. 2 in
order to make
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CA 02615567 2007-12-19
capture additional light from the LED 2203 and produce a more collimated and
intense
beam than would be achieved with a smaller concave minor 202. The LED 2203 is
placed on the reflector axis with respect to a focal point of the reflector
2202 to achieve a
desired degree of collimation for the reflector 2202. Placement at the focal
point will
result in the highest degree of collimation for the reflector 2202. Placement
nearer to the
reflector 2202 will likely produce a more focussed beam than placement away
from the
reflector 2202 with respect to the reflector 2202 along its axis.
[0306] An LED spotlight such as the LED spotlight 2200 can be made to be
mounted on
a vehicle. The LED spotlight has a head section housing 2201, which is
attached to a
tube 2208 by means of a hinge 2209 that permits movement of the head section
housing
2201 with respect to the tube 2208. Alternatively, the tube 2208 may have a
bend and a
swivel joint in lieu of the hinge 2209 to permit movement of the head section
housing
2201 with respect to the tube 2208. The tube 2208 passes through an
appropriate fitting
in the vehicle which the LED spotlight 2200 is attached to. A handle 2211 is
shown as
being attached to the tube 2208 by means of threads 2210, although other
arrangements
are possible to permit easy rotation of the tube 2208 to permit movement of
the head
section housing 2201 in directions other than allowed by the hinge 2209.
Further
alternative arrangements are possible, such as the head section housing 2201
having a
ball joint, two swivel joints, two hinges, or a hinge and a swivel joint.
[0307] The LED spotlight is shown as having associated circuitry 2204 that may
be
referred to as a driver circuit or an LED ballast. Output wires 2205 are shown
as
provided for the LED 2203 to receive electrical power from or through the
circuitry 2204.
Input wires 2206 are shown as provided for the LED spotlight 2200 to receive
electrical
power. The input wires are shown as being in a cable 2207 that passes through
weatherproof fittings 2212 that are provided in the head section housing 2201
and the
tube 2208.
[0308] The tube 2208 is shown as being closed at the end towards the hinge
2209. The
head section housing 2201 preferably incorporates waterproofing means such as
gaskets
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CA 02615567 2007-12-19
(not shown) for applications that require weatherproof; such as any externally
vehicle-
mounted LED spotlight 2200.
[0309] A lens 2213 is provided to protect the internal parts within the head
section
housing 2201 from weather, dirt and foreign objects. A diffuser 2214 is
provided but
may be omitted. The diffuser 2214 may be desired to achieve a smoother
appearance of
the beam formed by the reflector 2202. Without a diffuser 2214, the beam may
have a
square shape because the chip in the LED 2203 is typically square. Without a
diffuser
2214, the beam may have irregularities such as dim spots corresponding to
regions of the
chip in the LED 2203 where light is blocked by LED parts such as electrical
contacts on
its chip.
[0310] A switch is not shown as it may be preferable to have an external
switch, for
example, inside a vehicle to which such an LED spotlight 2200 is attached. If
desired, a
switch may be provided internal to the spotlight 2200.
[0311] The LED 2203 is preferably mounted to a heatsink 2215. The heatsink
2215
would be of a shape designed to minimize blockage of light 'reflected forwards
by the
reflector 2202.
[0312] Referring to FIG. 22, the heatsink 2215 is shown as a ring 2303 with
spokes 2301
that conduct heat from a central LED mounting area 2302. Any number of spokes
2301
can be used. If two spokes 2301 are used, then they can form a crossbar that
an LED can
be mounted onto the center of, which would be the central LED mounting area
2302.
The ring 2303, spokes 2301 and central LED mounting area 2302 are shown as a
single
piece of suitably thermally conductive material such as aluminum or zinc or an
alloy of
either of these metals. Alternatively, this arrangement may comprise more than
one piece
of thermally conductive material.
=
[0313] The heatsink 2215 may conduct heat to additional heatsinking parts
and/or to the
housing 2201 so that the housing 2201 can dissipate heat to the environment,
as described
above as being possibly done with the metal bar heatsink in the inspection
lamp 200 of
FIG. 2.
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[0314] Any optical filters or filtering lenses used in any embodiment of the
present
invention may have a filtering dye, be dichroic, or be an interference filter
or a colloidal
filter.
[0315] Any reflectors used in any embodiment of the present invention may have
dichroic reflective surfaces for any purpose such as filtering.
[0316] Any switches used in any embodiment of the present invention may be
momentary, non-momentary or of a kind that is usable both as a momentary
switch and
as a non-momentary switch.
[0317] Any batteries used in any embodiment of the present invention may be
rechargeable or non-rechargeable. Non-rechargeable batteries used in any
embodiment of
the present invention may be zinc carbon, alkaline, mercury, silver oxide,
lithium or any
other kind of non-rechargeable battery. Rechargeable batteries used in any
embodiment
of the present invention may be lead acid, nickel cadmium, nickel metal
hydride, lithium
ion, or any other rechargeable kind of battery. Any embodiment of the present
invention
that uses rechargeable batteries may further comprise a charging jack. Any
embodiment
of the present invention that uses rechargeable batteries may further comprise
circuitry
used in recharging of the batteries. Any embodiment of the present invention
that uses
rechargeable batteries may further comprise a charger.
[0318] Any embodiment of the present invention may further comprise means to
accept
power from an external source, whether or not it also uses any batteries.
[0319] Any embodiment of the present invention may have a thermal cutout
device to
prevent overheating of any LEDs or any other parts.
[0320] Any embodiment of the present invention may have indicator lamps for
purposes
such as indicating any status of any batteries or indicating that the LEDs are
producing
radiation. Fluorescent material may be added to an inspection lamp to give
visible
CA 02615567 2014-08-06
indication that fluorescence-causing radiation is being produced.
[0001] Any embodiment of the present disclosure may further comprise means to
achieve strobing of any LEDs, since doing so may achieve greater visibility of
fluorescent materials to be detected.
[0002] Any current limiting circuits used in any embodiment of the present
invention may comprise one or more integrated circuits. Any current limiting
circuits used in any embodiment of the present invention may comprise at least
one
integrated circuit and at least one discrete component. Any current regulating
circuit used in any embodiment of the present disclosure may be achieved with
one
or more discrete components and no integrated circuits.
[0003] The scope of the claims should not be limited by the preferred
embodiments
set forth in the examples, but should be given the broadest interpretation
consistent with the description as a whole.
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