Note: Descriptions are shown in the official language in which they were submitted.
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LED BEACON
The present invention relates to LED beacons and particularly, to an LED
beacon
having two or more LEDs providing light of the same color or of different
colors using an
improved optical system which may be associated with such LEDs and having a
collimating
lens and a plurality of condensing, coupling lenses which shift the focus of
the collimating
lens to the position of the LEDs and distribute the light from the LEDs
uniformly on the
collimating lens.
Light beacons have been provided with fresnel collimating lenses which provide
cylindrical beams from a light source located centrally in the collimating
lens. A typical light
beacon utilizing cylindrical fresnel collimating lens is shown in U.S. Patent
No. 3,221,162,
issued November 30, 1965 to Heenan et al. The distribution of light from a
beacon, and the
shaping of light from LED sources so as to provide output beams, have also
been
accomplished utilizing lenses associated with each LED in an LED array. See
for example,
U.S. Patent No. 6,425,678, issued July 30, 2002, to Verdes et al. and U.S.
Patent No.
5,237,490, issued August 17, 1993, to Ferng.
Combining lenses which shape the illumination pattern from the LEDs with a
fresnel
collimating lens having a cylindrical structure surrounding the LEDs and their
associated
lenses has not as yet been successfully accomplished, particularly when the
LEDs are in an
array mounted on or around a post to enable heat to be dissipated from the
LEDs. One
approach has been suggested in U.S. Patent No. 7,252,405, issued August 7,
2007, to
Trenchard et al. There, an array of LEDs mounted on a post is surrounded by a
tubular light
diffusing member. This light diffusing member distributes the LED light on the
fresnel
collimating lens. Since the diffusing member does not control distribution of
the light, it is
not efficient in coupling the light from the LEDs to the collimating lens and
reduces the
intensity of the beacon. Also, utilizing a diffusing element is not efficient.
It has been
proposed to use lenses along the optical axis of a pair of LEDs. These lenses
merely direct
the light emitted from the LEDs radially outwardly to a fresnel collimating
lens. They do not
move the focus of the collimating lens to the position of the LEDs. The design
is limited to
opposed LEDs located along a central axis of the beacon, thereby limiting the
light output of
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the beacon to the light which can be provided by only two LEDs. The design of
such a two
LED system is shown in U.S. Patent No. 7,534,009, issued May 19, 2009, to
Trojanowski et
al.
A multi-color warning light is described in U.S. Patent No. 6,483,439, issued
November 19, 2002, to Vukosic et al., and multi-colored industrial signal
device is described
in U.S. Patent No. 6,626,557. However, such patents although describing multi-
color
operation do not describe the improved optics of the present invention, and
thereby do not
provide the improved performance enabled by such optics.
Accordingly, it is an object of the present invention to provide improved LED
beacons.
It is an object of the present invention to provide an improved LED beacons
providing
illumination in one or more colors and provide such colors selectively and in
selected
sequences.
It is a further object of the invention to provide a multi-color LED beacon
having a
plurality of LEDs for emitting light of different colors, which are in
different groups of two or
more LEDs, where at least one LED in each group being of a different color,
and such groups
are arrayed along the same level and circumferentially distributed within the
beacon about a
member or post within an optical system that efficiently couples the light
from each LED
when activated to a collimating lens surrounding the LED notwithstanding the
non-uniform
illumination emitted from the LED and the nominal focus of the collimating
lens being along
an axis shifted radially inwardly from the location of the LED.
It is a still further object of the invention to provide single color and
multi-color LED
beacons each having an improved optical system including a collimating lens
and a
condensing, coupling lens between the LED and the collimating lens which
provides for
relocation of the focus of the collimating lens and enabling collimating
lenses of various
diameter and height to be used with the same LEDs.
Another object of the invention is to provide single color and multi-color LED
beacons having a plurality of LEDs distributed about an axis to efficiently
couple the light
from the LEDs to collimating optics, such as a fresnel lens formed in a dome,
or beam
forming optics, such as a rotational or stationary parabolic reflector, using
a condensing,
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coupling lens as adaptor for relocating the focus of, and redistributing the
light from the LEDs
to, such collimating or beam forming optics, and thereby providing an intense
illuminating
beacon suitable for use as a warning light.
Briefly described, the present invention enables the use of cylindrical
fresnel lenses of
the type conventionally used in beacons for collimating the light from a
central light source
and enables collimating fresnel lenses of different diameters to be used with
a plurality of
LEDs for emitting light of the same or different colors. To provide a beacon
illuminating
selectively light in two or more colors, the plurality of LEDs are in
different groups of two or
more LEDs, where at least one LED (or LED element) in each group can provide
light of a
different color. Each group of LEDs may represent separate LEDs (or LED
emitters of a
multi-color LED) and are mounted circumferentially spaced from each other
around a central
axis, as in a plane perpendicular to the axis (a horizontal plane in the
typical installation). The
conventional fresnel collimating lens is focused along a central optical axis
which is spaced
radially inward from the location of the LEDs. A condensing lens arrangement,
preferably a
meniscus (inside concave and outside convex) lens is used to shift the focus
of the collimating
lens radially outward from the center to the location of the LEDs. The
condensing lens also
shapes the light emitted from the LEDs so that it is uniformly distributed
over the inside
surface of the cylindrical fresnel collimating lens, thereby utilizing
efficiently substantially all
of the LED illumination, even though the illumination is not uniform from the
LED itself.
In a multi-color LED beacon, all or different LEDs of the same color are
selectively
activated to enable the beacon to emit light of such color. By selectively
activating LEDs of
the same colors or different colors at different times different sequences or
patterns may be
generated. Both the light output and the optical efficiency of single color
and multi-color
LED beacons are enhanced in accordance with the invention.
The present invention in another embodiment provides a rotational or
stationary single
color and multi-color LED beacon in which beam forming optics of a reflector
are provided
instead of the collimating fresnel lens described above. The reflector may be
a parabolic
reflector which can be either stationary, or rotated by a (motor driven)
rotator about the
internal optical assembly of the LEDs and condensing lens.
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Preferably, a multi-color LED beacon is provided having LEDs (or LED emitters)
providing light of two different colors, e.g., red and green, or red and blue,
which are
selectively activated with a programmable controller. LED groups are mounted
along the
member at the same level in the beacon. along opposite sides of the member
facing the optics
of a collimating fresnel dome lens, via condensing lenses which focus light of
each of the
LEDs when activated so as to distribute it over the fresnel lens to provide
more uniform
illumination than if the condensing lenses were not present. The member may be
a post or
metallic bar (rectangular or square in cross-section) serving as the heat sink
for LED circuit
boards or assemblies mounted thereto. The patterns may be continuous or
flashing or may be
sequential, simulating in different colors, different traveling, moving or
rotating patterns of
illumination under control of the programmable controller, such a
microprocessor or
microcontroller.
The foregoing and other objects, features, and advantages of the invention
will
become more apparent from a reading of the following description in connection
with the
accompanying drawings wherein:
FIG. 1 is a schematic, elevational view of an LED beacon incorporating the
invention;
FIG. 2 is an exploded view of the LED beacon shown in FIG. 1;
FIG. 3 is a perspective view of the LED beacon shown in FIGS. 1 and 2 with the
cap
or drum providing a cylindrical fresnel collimating lens not shown in the
drawing so as to
illustrate the internals of the beacon;
FIG. 4 is an exploded view of the condensing lens system of the beacon shown
in
FIGS. 1, 2 and 3;
FIG. 5 is a multi-part view consisting of FIGS. 5A-5F of a condensing
meniscus,
coupling lens in the optical system shown in FIG. 4, wherein FIG. 5A is a
sectional view of
the lens taken along the line A-A in FIG. 5B; FIG. 5B is a horizontal
sectional view through
the lens in a horizontal plane through the center of the lens; FIG. 5C is a
perspective view of
the lens taken from the right as viewed in FIG. 5A; FIG. 5D is an elevational
view of the lens
looking from the right side of FIG. 5A; FIG. 5E is a perspective view of the
lens from the
inside thereof; and FIG. 5F is a perspective view of the lens from the outside
thereof;
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FIG. 6 is a perspective view of an LED beacon of another embodiment of the
present
invention showing an LED beam beacon;
FIG. 7 is a schematic, elevational view of an LED beacon incorporating the
invention
for multi-color operation;
FIG. 8 is an example of a multicolor LED having four LED elements in a common
module which may be utilized in the LED beacon on FIG. 7;
FIG. 9 is a perspective view of an assembly of the LEDs in the beacon of FIG.
7 apart
from the rest of the assembly shown in FIG. 7;
FIG. 10 is an exploded perspective view of an LED beacon of FIG. 7 which is
similar
to FIG. 2; and
FIGS. 11A and 11B are schematic diagram of the electronics of the LED beacon
on
FIG. 7.
Referring to the drawings, there is shown in FIGS. 1, 2, and 3, an LED beacon
10
having a cylindrical fresnel collimating lens 12 which may be attached to a
base 14 via a
collar 16. Inside the collimating lens 12 is an LED assembly 18. This assembly
18 has a
central post 20 on which is mounted an array of LEDs, e.g., four in number
with one on each
side of post 20. The post 20 is square in cross-section, and the LEDs are 900
apart. The
LEDs 22 are connected via connectors 24 to a circuit board which is potted in
a pan 26, as
best shown in FIGS. 2 and 3. The pan 26 is mounted on a spacer 28 which is
attached by
screws 30 to bars 32 projecting radially from the base 14 (see FIG. 3).
Another screw 34
attaches the post 20 to the spacer 28 through the pan 26. Other screws 36
attach the pan 26 to
the spacer 28. Although the fresnel lens 12 is referred to herein as of a
collimating type,
depending on the lens 12, the lens 12 may be substantially collimating, or
other lens may be
used for lens 12 to refract light incident thereto to provide a desired
illumination pattern
exiting beacon 10.
Screw threads 38 on a cylindrical portion of the base 14 enable the collar 16
of lens 12
to engage base 14, where collar 16 has screw thread along the inner surface of
collar 16 which
screw onto threads 38 of base 14 thereby attaching the lens 12 to the base 14
and sealing the
assembly 18 and the pan 26 and spacer 28. The seal may use an o-ring 40. The
lens 12 may
be molded plastic material formed into an inverted cup or dome, which may be a
desired
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color. Such inverted cup or dome has a surface defining fresnel lens 12 inside
of which LED
assembly 18 is located. As shown in FIG. 3, the circuit board has circuit
components, such as
component 42 which provides circuitry for controlling of, as for example
flashing, the LEDs
22. Also connected to the circuit board are connectors 44 which connect wires
(not shown).
These wires extend outside of the pan 26 and out of the unit through a hole 46
through the
base 14. The LED assembly 18 has a plurality of meniscus condensing, coupling
lenses 50,
one for each of the LEDs 22. The central horizontal plane through which the
optical axes of
these lenses 50 extend is through the LEDs 22.
The lenses 50 serve two purposes. First, the lenses 50 shift the focus of the
fresnel
collimating lens 12 (indicated as f, FIG. 5A) to the location of the LEDs 22
(indicated as F in
FIG. 5A). Second, as shown in FIG. 1, the condensing lenses 50 also serve the
purpose of
condensing the illumination emanating from the LEDs 22 so that such
illumination covers
(paint) the inside of the fresnel collimating lens 12. By virtue of the
refraction in the lenses
50, the majority of illumination (approximately +73 about the horizontal
optical axis) from
the LEDs 22 is directed to the collimating lens 12 by virtue of the condensing
lenses 50.
About 20 of the illumination as shown by the area 55 on the upper side of the
optical axis is
refocused (condensed) into the portion of the illumination which hits the lens
12. Similarly
there is another area of about 20 on the lower side of the optical axis which
is condensed and
hits the lens 12. Thus the radiation pattern of each LED for typical
commercially available
LEDs such as sold by Cree, or other LED suppliers would not hit the lens 12 is
utilized by
virtue of the adapter optics provided by the coupling, condensing lenses 50,
thereby
enhancing the optical efficiently of the beacon 10. The lenses 50 operate to
shift the focus of,
and distribute the LED light substantially uniformly to, collimating lens 12
thereby efficiently
using light from the array of LEDs 22 on post 20 to provide an intense
illuminating beacon 10
suitable for use on emergency vehicles, and for other vehicles and industrial
applications for
warning beacons.
As shown in FIGS. 4 and 5, the meniscus lenses are in four segments each
defining
angles of 90 so that when assembled on the post 20, they encompass (external
around) the
entire post over 360 . The lenses have upper and lower collars 58 which are
connected to the
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post 20 by screws 60. The segments may each be of molded optical material,
such as plastic,
forming the desired lens shape.
The LEDs 22 and the connectors 24 are on circuit boards 70 to which the LEDs
22 and
the connectors 24 are wired. Thermal transfer pads 72 of heat conductive
material are
sandwiched between the circuit boards 70 and the sides of the post 20 to fill
the gap between
the boards 70 and the post 20 so as to facilitate the transfer of heat from
the LEDs to the
ambient via the post. When the segments of the condensing lens 50 are
assembled on the
post, they are located by flanges 76 on the top thereof and by alignment pins
78 (see FIGS.
5A and 5E). FIG. 5A illustrates the design of an exemplary condensing lens 50.
The lens
material may be polycarbonate lens material.
The concave inside of the lens 50 has a radius of 0.6782 inches. The outer
convex
surface has a radius of 0.6500 inches. The thickness of the lens along its
optical axis is 1.1
inch and the distance to the LED location, F, is 0.2915 inches. The focus of
the collimating
lens 12 is shifted from its actual focus at f, to the position of the LEDs at
F, by 0.2915 inches
with the exemplary lens design, as shown in FIG. 5A.
Thus, an LED beacon 10 having an optical system including a collimating lens
12 and
a condensing, coupling lens 50 between the LEDs 22 and the collimating lens
12, which not
only provides for relocation of the focus of the collimating lens 12, but also
enables
collimating lenses 12 of various diameter and height to be used with the same
array of LEDs
22.
Referring to FIG. 6, another embodiment of the LED beacon is shown in which
instead of using collimating optics of fresnel lens 12, beam forming optics of
a collimating (or
substantially collimating) reflector 75 is utilized. This reflector 75 may be
a parabolic
reflector which can be rotated about the internal optical assembly 18 of the
LEDs 22, post 20,
and adapter optics 50. A rotator mechanism 83, 84 on a base 82, may be
attached via
grommets 81 to a support structure (not shown, e.g., a vehicle roof, light
bar) to provide a
rotating LED beam beacon. The rotating reflector mechanism may be of the type
in U.S.
Patent No. 5,860,766, issued January 19, 1999, to Richardson, which is herein
incorporated
by reference. The optical assembly 18 and rotator mechanism 83, 84 may be
located
internally in a transparent or translucent dome, which may of a desired color.
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The reflector 75 may also be stationary, instead of rotatable, by removal of
the rotator
mechanisms 83, 84 (or non-actuation thereof) to provide a stationary LED beam
beacon. The
optical assembly 18 may be the same as described earlier. Although four LEDs
22 on post 20
is preferred, optionally a single LED may be used in optical assembly 18 on
one side of post
20 to direct light toward the stationary reflector 75 via the adapter optics
50. Accordingly, a
parabolic reflector 75 that is stationary or can be rotated about the internal
optical assembly
18 is provided, but other beam shaping optics may be used depending on the
particular
application.
LEDs 22 on post 20 may number four, one on each side of the post 20 in optical
assembly 18. However, more than four LEDs 22 may be used, such as eight in
number by
providing two LEDs 22 on each side of post 20, but other number of LEDs may be
used. The
LEDs 22 on post 20 may provide light of the same color.
Referring to FIG. 7, a multi-color LED beacon 10a is shown which utilizes the
same
optics of the condensing lenses 50 and fresnel lens 12 as described above for
beacon 10, but
different color emitting LEDs are provided to enable beacon 10a to provide
illumination in
two or more different colors by selectively activating LEDs. The LEDs of
beacon 10a are in
four different groups 23 each of which have two or more LEDs, where at least
one LED in
each group 23 is of a different one of the colors to be illuminated by beacon
10a. In the
example of FIG. 7, each side of post 20a has a group 23 of two LEDs 22a and
22b mounted
thereto, each emitting light of a different color when activated, such as red
and blue,
respectively. Four different groups 23 of LEDs are thus mounted to post 20a
circumferentially spaced from each other around a central axis provided by
post 20a.
The LEDs 22a and 22b of each group 23 represent two different LED elements
which
may be in the same or different packages when mounted to post 20a. For
example, one type
of group 23 may be a multicolor LED module 23a such as shown in FIG. 8, which
can be
considered as being four LEDs 22c, 22d, 22e, and 22f each provided by a
different LED
element (or emitter unit, also known as a die) in module 23a, where LEDs 22c
and 22e can
provide illumination of one color (e.g., red), and elements 22d and 22f can
provide
illumination of another color (e.g., blue). LED module 23a shown for example
in FIG. 8 is
manufactured by Cree, Inc., but other multi-color LED modules may be used.
Different
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groups 23, either provided in a module of two or more LEDs or as separate
LEDs, are
provided on the fours sides of post 20a at the same level along such post so
that the LED
elements 22c-f can have their light collected by the condensing lenses 50 and
then forwarded
to the fresnel lens 12 so as to provide the illumination from the beacon 10a
in the patterns
which are selected by the programmable microcontroller 90 of FIG. 11B
described below.
The four group 23 of LEDs 22a and 22b may on four common circuit boards or
assemblies mounted to four sides of post 20a and such circuit boards connect,
via connectors
24 on post 20a to a circuit board 25 which is potted in a pan 26, as best
shown in FIG. 9.
Post 20a may be a metallic bar member attached to the LED circuit boards or
assemblies that
mount each of groups 23 of LEDs to post 20a. Such bar member may be
rectangular or
square in cross section.
Referring to FIG. 10, an exploded view of LED beacon 10a providing multicolor
illumination is shown having the LED groups 23 mounted on post 20a, such as
shown in FIG.
7 or 9 with circuit board 25 and spacer 28a, otherwise the assembly and other
elements of
FIG. 10 are the same as described earlier and provide the same function.
Spacer 28a is used
which provides not only the same function as spacer 28 described earlier, but
further serves as
a heat sink in conjunction with the metallic bar member providing the post
20a, thereby
facilitating removal of heat from the LEDs in the operation thereof. If
needed, such spacer
28a can be provided when single color LEDs 22 are used.
Referring to FIGS. 11A and 11B, the electronics of the multi-color LED beacon
10b
are shown. Such electronics being provided on circuit board 25 (FIG. 11B)
which connect to
LED circuits (FIG. 11A) for each of the LEDs of beacon 10a. The LED circuits
extend within
post 20a or along the outside of post 20a to the LEDs along the post 20a, or
part of the LED
circuit may also be provided on circuit board 25. Each of the four groups 23
of LEDs 22a and
22b is preferably mounted on a different circuit board or assembly 86, 87, 88
and 89 (see e.g.,
86 and 87 of FIG. 7) arrayed along the same horizontal level or plane with
respect to vertical
post 20a, rather than as separate units (see e.g., FIG. 9). Thus, there are a
total of eight LED's
in beacon 10a of this example, where enable lines 86a, 86b can activate LED
22a and 22b,
respectively, of assembly 86, enable lines 87a, 87b can activate LED 22a and
22b,
respectively, of assembly 87, enable lines 88a, 88b can activate LED 22a and
22b,
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respectively, of assembly 88, and enable lines 89a, 89b can activate LED 22a
and 22b,
respectively, of assembly 89. Each enable line when high (on) switches, via a
MOSFET, to
drive current to its associated LED, and when the enable line is low (off),
the MOSFET
disables drive current to its associated LED. In this example, LED beacon 10a
can provide
dual color illumination in one of two different colors, referred to as Color A
by activating
LEDs 22a or Color B by activating LEDs 22b, along post 20a.
A microcontroller (or microprocessor) 90 outputs signals along each of enable
lines
86a-b, 87a-b, 88a-b, 89a-b, to activate different LEDs associated therewith to
enable different
patterns of Color A or Color B light to be emitted from beacon 10a. The
microcontroller 90
operates in accordance with a program stored in its memory (ROM or RAM) to
enable
operation of beacon 10a. For example, microcontroller 90 may be a PIC
microcontroller as
shown in FIG. 11B, but other programmable logic device may be used which can
output
signals on lines 86a-b, 87a-b, 88a-b, 89a-b, to provide desired a plurality of
different
illumination patterns of one or more colors associated with LED groups 23.
To enable each Color A and Color B, two inputs 92a and 92b, respectively, are
provided to microcontroller 90 to select one of Color A LEDs 22a or Color B
LEDs 22b,
according to the selected pattern via a pattern select input(s) 93 to the
microcontroller 90. By
placing on input(s) 93 signals representative of a one of different values,
addresses, codes, or
instructions, detectable by the microcontroller 90, one of multiple different
patterns of
illumination may be selected utilizing light of Color A or Color B, or both,
responsive to
inputs 92a and/or 92b are high (enabled) or low (disabled). The present
invention is not
limited to any particular means for pattern input selection to microcontroller
or programmable
logic device 90.
If the signal on pattern select input 93 is detected by microcontroller 90 for
operating
LED beacon 10a in a flash mode, then either Color A LEDs 22a are periodically
activated via
output along their enable lines 86a, 87a, 88a, and 89a at a preselected flash
rate, or Color B
LEDs 22b are periodically activated via output along their enable lines 86b,
87b, 88b, and
89b. For example, in Color A flash mode, Color A input 92a is high (enabled),
and Color B
input 92b is low (disable), and microcontroller 90 then alternates outputting
an activate
(enable) signal on all four LED enable lines 86a, 87a, 88a, and 89a
simultaneously to
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illuminate Color A LEDs 22a in each of assemblies 86-89, and the disabling all
four LED
enable lines 86a, 87a, 88a, and 89a simultaneously to turn off Color A LEDs
22b. Color B is
not illuminated from beacon 10a. In Color B flash mode, Color B input 92b is
high (enable),
and Color A input 92a is low (disable), and microcontroller 90 then alternates
outputting an
activate (enable) signal on all four LED enable lines 86b, 87b, 88b, and 89b
simultaneously to
illuminate Color B LEDs 22b in each of groups 86-89, and the disabling all
four LED enable
lines 86b, 87b, 88b, and 89b simultaneously to turn off the Color B LEDs 22b.
Color A is not
illuminate from beacon 10a. The rate of flash is preset in memory of
microcontroller 90, such
as every 0.5 second. In Color A and B flash mode, both Color A and Color B
inputs 92a and
92b are high (enabled) and beacon 10a then alternates between flashing in
Color A and B, but
only one color is emitted on at any one time. Thus, microcontroller 90
alternates between
outputting enable signals on LED enable lines 86a, 87a, 88a, and 89a, while
disabling LED
enable lines 86b, 87b, 88b, and 89b, and then enable signals on LED enable
lines 86b, 87b,
88b, and 89b, while disabling LED enable lines 86a, 87a, 88a, and 89a. The
flashing rate is in
accordance with a preset on and off intervals stored in memory of the
microcontroller 90. A
clock in the microcontroller 90 is used to measure each of the flash
intervals.
If the signal on pattern select input 93 is detected by microcontroller 90 for
operative
LED beacon 10a in rotating mode, the LEDs 22a or 22b along each of assemblies
86-89 are
sequentially activated by microcontroller 90 so that the light from beacon 10a
is in a traveling,
moving, or rotating pattern. For example, if Color A input 92a is high
(enabled), and Color B
input 92b is low (disabled), then the microcontroller 90 sequentially
activates only one of
enable lines 86a, 87a, 88a, and 89a at a time around post 22a to simulate a
traveling, moving,
or rotating light about 360 degrees of beacon 10a, and all of the Color B LEDs
22b are off.
The below table shows the timing for sequentially activation LEDs 22a of
circuit boards 86-
89, where X indicates when an enable line is active and thus the LED
associated with the
enable line is illuminating light there from.
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Time in Seconds
Microcontroller Output 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Output to Enable Line 86a X X
Output to Enable Line 87a X X
Output to Enable Line 88a X X
Output to Enable Line 89a X X
Similarly, if Color B input 92b is high (enabled), and Color A input 92a is
low
(disabled), then the microcontroller 90 sequentially activates only one of
enable lines 86b,
87b, 88b, and 89b at a time around post 22a, and all of the Color A LEDs 22a
are off. If
Color A enable and Color B inputs 92a and 92b are both high, then
microcontroller 90
sequentially activates only one of enable lines 86a, 87a, 88a, and 89a, 86b,
87b, 88b, and 89b
at a time around post 22a so that the beacon alternates between rotating Color
A and Color B.
A different pattern may also be selected in which microcontroller 90 flash the
same color
multiple times in a quick sequence prior to alternating to the other color.
The time intervals
of the above table are exemplary, and other time intervals may be used as
stored in memory of
microcontroller 90.
Other or different patterns can be provided by separately enabling or
simultaneous
enabling each LED element 22a and 22b on each post 20a, as desired, by
programming
microcontroller 90. For example, faster flash rates or more attention getting
flash "bursts"
may be selectable in one or both color outputs order to emphasize higher level
of warning.
Further, the LEDs 22a or 22b in beacon 10a may be activated to operate in a
continuous mode
in the Color A or B, respectively.
A synchronization line 94 is provided which when switched from high to low,
microcontroller 90 reset the cycle of its internal clock. Such is useful when
two different
LED beacons 10a need to be synchronized to each other so that they flash at
the same time. A
user interface (keypad, buttons, or switches) may be provided to
enable/disable Color A and B
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inputs 92a and 92b, respectively, and to select different ones of patterns
along pattern select
input 93. Inputs 92a, 92b, 93, and 94 may also interfaced to another computer
system,
controller, or device to externally control beacon 10a operation.
The present invention broadly relates to use of an adapter optic (the
condensing
coupling lenses 50) in a horizontal array with horizontal LED's 22 or LED
groups 23 (or 23a)
along vertical post 20 or 20a so as to obtain the full benefits of LED
illumination vs.
conventional incandescent, halogen or strobe illumination. The collimating,
fresnel lenses do
not have to be redesigned to accommodate LED illumination. Existing domes
providing
collimating lens for the beacon, and tooling for producing the domes may be
used thereby
reducing development effort and financial cost in providing an LED beacon 10
and 10a. The
adapter optics enables increase of the light output significantly over prior
LED designs even
where no optics internal of the dome or outside lens is used. As with LED
beacon 10
described in FIG. 6, rotating reflector 75 may also be used in the LED beacon
10a instead of
using collimating optics of fresnel lens 12.
From the foregoing description, it will be apparent that there has been
provided an
improved LED beacons for single color or multi-color operation. Variations and
modifications in the herein described LED beacons within the scope of the
invention will
undoubtedly suggest themselves to those skilled in the art. Accordingly, the
foregoing
description should be taken as illustrative and not in a limiting sense.
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