Note: Descriptions are shown in the official language in which they were submitted.
Attorney Docket No. 04-1-721
CA 02510370 2005-06-21
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STEM MOUNT FOR LIGHT EMITTING DIODE
This application claims priority from Provisional Patent Application No. 60/ ,
, filed
July 16, 2004.
TECHNICAL FIELD
This invention relates to light sources and more particularly to light sources
employing
light emitting diodes (LED or LEDs) and more particularly to light sources
useful in the
automotive field such as for headlights, taillights, stoplights, fog lights,
turn signals, etc.
Still more particularly, it relates to such light sources packaged to achieve
industry
BACKGROUND ART
In the past, most automotive light sources have involved the use of
incandescent bulbs.
While working well and being inexpensive, these bulbs have a relatively short
life and,
of course, the thin filament employed was always subject to breakage due to
vibration
Recently some of the uses, particularly the stoplight, have been replaced by
LEDs.
These solid-state light sources have incredible life times, in the area of
100,000 hours,
and are not as subject to vibration failures. However, these LED sources have
been
hard-wired into their appropriate location, which increases the cost of
installation. It
would therefore be an advance in the art if an LED light source could be
provided that
had the ease of installation of the incandescent light sources.
It would be a still further advance if LED light sources employing single LEDs
could be
utilized, with such light sources providing acceptable illumination, good heat
removal
and ease of use.
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DISCLOSURE OF INVENTION
It is, therefore, an object of the invention to obviate the disadvantages of
the prior art.
It is another object of the invention to enhance LED light sources.
These objects are accomplished, in one aspect of the invention, by tile
provision of a
lamp assembly that has a reflector for directing light in a given direction.
The reflector
has an aperture therein and a thermally conductive post is fitted into the
aperture. The
post has a first surface within the reflector and a second surface outside of
the reflector.
A single, side emitting, LED light source is fixed to the first surface, a
heat sink is fixed
to the second surface and circuitry is associated with the LED light source
for supplying
power thereto.
In one embodiment of the invention the light source includes a cap having a
second
reflector provided thereon and in another embodiment of the invention the
light source
includes a dome-shaped, transparent element having sidewalk and a closed top
having at
least one metallized surface. An optic tailored to a specific emission pattern
can be
included in the transparent element.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a diagrammatic sectional view of an embodiment of the invention; and
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Fig. 2 is a partial, diagrammatic sectional view of an alternate embodiment,
BEST MODE FOR CARRYING OUT THE INVENTION
For a better understanding of the present invention, together with other and
further
objects, advantages and capabilities thereof, reference is made to the
following
disclosure and appended claims taken in conjunction with the above-described
drawings.
Referring now to the drawings with greater particularity, there is shown in
Fig. 1 a lamp
assembly 10 that comprises a reflector 12 for directing light in a given
direction. An
aperture 14 is formed in the reflector, substantially in the base thereof, and
a thermally
conductive post 16 is fitted in the aperture 14 and has a first surface 18
within the
reflector and a second surface 20 outside of the reflector. The post 16 is
preferably a
metal such as copper. A single, side emitting, LED light source 22 is fixed to
the first
surface 18, preferably via an electrically insulating but thermally conductive
member 23.
A heat sink 24 is fixed to the second surface 20 and preferably is an inherent
part thereof
to insure good heat conductivity between the post 16 and the heat siillc 24.
Circuitry 26,
which can be mounted on a printed circuit board, is associated with the LED
light source
22 for supplying power thereto and preferably is mounted outside of the
reflector.
Suitable electrical connections, not shown, can be supplied from the circuitry
26 to the
LED light source 22 via insulated wires running up the side of the post 16 or
threaded
through longitudinal apertures formed in the post 16. Alternatively, an
electrically
insulating material supplied with conductive traces can cover the post 16.
The light source 22 can be mounted alone atop the post 16 or it can have a cap
28 that
includes a secondary reflector 30 mounted thereon. With a cap 28 in place,
during
operation the LED light source can emit light rays directly to the reflector
12, as shown
by arrow 60, or the light rays can be emitted toward the second reflector 30
and
redirected toward the reflector 12, as shown diagrammatically by the arrow 62.
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Alternatively, the LED light source 22 can be covered by a dome-shaped,
transparent
element 32 having sidewalk 34 and a closed top 36 having at least one
metallized
surface 38. The sidewalk 34 can include at least one optic 40, which can take
the form
of a molded-in lens tailored to provide a specific emission pattern.
The post 16 has a given length measured along a longitudinal axis 42 whereby
the LED
light source 22 is positioned at a focal point of the reflector 12.
The reflector 12 can be any desired shape but for use as an automotive
taillight assembly
is preferably concave. Still more particularly, the shape can be a parabolic
section.
Thus there is provided a single LED light source suitable for an automotive
taillight
assembly having easy installation and good heat removal. Additional optics can
be
employed to achieve customized light emission.
While there have been shown and described what are present considered to be
the
preferred embodiments of the invention, it will be apparent to those skilled
in the art that
various changes and modifications can be made herein without departing from
the scope
of the invention as defined by the appended claims.
