U.S. patent application number 13/189419 was filed with the patent office on 2012-09-20 for spherical light output led lens and heat sink stem system.
Invention is credited to Malek Bhairi.
Application Number | 20120235553 13/189419 |
Document ID | / |
Family ID | 44150057 |
Filed Date | 2012-09-20 |
United States Patent
Application |
20120235553 |
Kind Code |
A1 |
Bhairi; Malek |
September 20, 2012 |
Spherical Light Output LED Lens and Heat Sink Stem System
Abstract
This light emitting diode (LED device provides a 360 degree
lighting angle in the horizontal plane and a 300 degree lighting
angle in the vertical plane while simultaneously addressing LED die
thermal management, which is critical to high lumen output LEDs.
This LED lighting device is comprised of the LED lens, the LED
holder and the heat sink stem. Light produced by at least one LED
die traveling vertically is diffused by the top refractive portion
of the lens. Light rays directed towards the pointed elements are
totally internally reflected downwards then refracted out of the
lens, thus resulting in a spherical light pattern. This technology
is designed as a replacement for conventional light sources, such
as incandescent light bulbs, halogen bulbs, CFLs (compact
fluorescent lamps) and metal halide lamps.
Inventors: |
Bhairi; Malek; (Claremont,
CA) |
Family ID: |
44150057 |
Appl. No.: |
13/189419 |
Filed: |
July 22, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12643182 |
Dec 21, 2009 |
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13189419 |
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Current U.S.
Class: |
313/46 |
Current CPC
Class: |
H01L 33/62 20130101;
F21Y 2115/10 20160801; H01L 2224/32245 20130101; H01L 33/642
20130101; H01L 2924/181 20130101; G02B 19/0071 20130101; F21K 9/60
20160801; F21V 7/0091 20130101; H01L 33/58 20130101; G02B 19/0028
20130101; H01L 2224/48247 20130101; F21V 5/04 20130101; G02B
19/0061 20130101; H01L 2224/73265 20130101; F21K 9/232 20160801;
H01L 2224/48091 20130101; H01L 2924/00014 20130101; H01L 2224/73265
20130101; H01L 2224/32245 20130101; H01L 2224/48247 20130101; H01L
2924/00 20130101; H01L 2924/181 20130101; H01L 2924/00012
20130101 |
Class at
Publication: |
313/46 |
International
Class: |
H01J 7/24 20060101
H01J007/24 |
Claims
1-10. (canceled)
11. A heat sink stem comprising: a body includes a means for
coupling to a lens or lens holder; a thermally conductive material;
a stem length used as a platform for light propagation lead wires
traveling the length of the stem to an LED light source.
12. The heat sink stem of claim 11, wherein the heat sink stem
comprises: a cylindicular body; a protruding cylindicular center
section with twist and lock channels; positive and negative contact
points; A twist and lock attachable lens and holder with positive
and negative contact points.
13. The heat sink stem of claim 11, wherein the heat sink stem
comprises: a cylindicular body; a protruding cylindicular center
section with twist and lock channels; positive and negative contact
patches; A twist and lock attachable lens and holder with positive
and negative contact patches.
14. The heat sink stem of claim 11, wherein the heat sink stem
comprises: a cylindicular body; a protruding cylindicular center
section with a screw type pattern on the walls of the perimeter;
positive and negative contact points; a screwable lens and holder
with positive and negative contact points
15. The heat sink stem of claim 11, wherein the heat sink stem
comprises: a cylindicular body; positive and negative contact pads;
an attachable lens and holder with solderable positive and negative
contact leads.
16. The lens and holder package of claim 11, wherein the holder is
made of metal.
17. The heat sink stem claim of 11, wherein the stem is made of a
thermally conductive plastic.
18-21. (canceled)
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of Invention
[0002] This invention relates to light emitting diode (LED) devices
and more specifically, to an improved LED lens and heat sink stem
for emitting a spherical light pattern and dissipating heat.
[0003] 2. Description of Related Art
[0004] All light sources convert electrical energy into radiant
energy and heat in various proportions. Light emitting diode (LED)
devices generate little or no IR (infrared) or UV (ultraviolet)
light, but convert only 15% to 25% of the electrical power to
visible light, the remainder is converted to heat that must be
conducted from the LED die to an underlying circuit board, heat
sink, etc.
[0005] In order to maintain a low junction temperature to keep good
performance of an LED, heat generated by the LED must be
dissipated. A build up of heat inside the LED device leads to color
shift, reduced light output, shortened life and ultimately device
failure. In addition, drive current, thermal path and ambient
temperature also affects the junction temperature. Furthermore,
high-flux LEDs, which are needed for conventional light
illumination, require higher drive currents which further increases
junction temperature.
[0006] FIG. 1 illustrates a sectional view of a conventional 360
degree lighting angle LED 100 having one or more LED dies 101 which
sits atop the first electrode 104. A bonding wire 102 connects the
LED die 101 to the second electrode 103. Light emitted by the LED
die 101 exits the transparent encapsulate 105 in all directions.
The upper surface 106 acts as a partial reflector, reflecting some
of the light downwards. In another 360 degree LED prior art
example, the encapsulate 105, takes the shape of a sphere 107.
[0007] If such LED devices are to be used as conventional lighting,
then high-flux LEDs must be incorporated. High-flux LEDs produce
more heat, and heat must be moved away from the die 101 in order to
maintain expected light output, life and color. Unfortunately, the
prior art example contains a critical flaw; it neglects to address
LED thermal management; as it does not contain any significant heat
sink to draw out the heat via conduction. Electrodes 103 and 104
may draw out some heat; though the majority of the heat generated
is trapped inside by the insulating plastic resin encapsulate 105
or 107. Such LED lamps are thus relegated for use with only lower
flux LEDs, which would not be suitable for conventional lighting
needs. Retrofitting this LED lamp with a sufficient heat sink,
beneath the LED die 101 would revert the 360 degree lighting angle
back to typical 30 to 140 degree lighting angles.
[0008] A need therefore exists for an LED device designed to emit a
spherical light pattern while successfully managing the heat
generated. Such a device would be advantageous for use as a
replacement to current conventional light sources or other
applications where spherical light patterns are desired.
SUMMARY OF THE INVENTION
[0009] This LED lighting device is comprised of an LED lens, an LED
holder and a heat sink stem. The crown of the LED lens features
twin convex peaks; other iterations may include a convex or concave
crown. Circumscribing the lens are 5 pointed, reflective and
refractive elements. This LED lens is attachable or fixed to the
LED holder. The LED holder houses the LED die, the positive and
negative terminals, and the heat sink slug. The holder is attached
to the heat sink stem. In the preferred embodiment, the holder and
the heat sink stem are one entity. In another embodiment, the LED
holder has a hollowed out cylinder base with positive and negative
contact patches. In another embodiment, the LED holder has a
hollowed out cylinder base with positive and negative contact
points. In yet another embodiment, the LED holder has a hollowed
out cylinder base with a screw type pattern on the inner walls with
positive and negative contact areas.
[0010] The LED lens and each of the various embodiments of the LED
holder are attached or fixed atop their individually related heat
sink stem. The heat sink stem performs the critical task of drawing
heat out of the device. The stem is also used as a means of
conveying power to and from the LED Device. Finally, the stem
provides an elevated and unobstructed platform for light
propagation.
[0011] Light produced by an LED die is diffused upwards and
outwards by the top refractive crown portion of the lens. Light
rays directed towards the pointed elements are totally internally
reflected downwards then refracted out of the lens. The result is a
spherical light pattern. Heat produced by the LED die is conducted
by the Heat sink slug and is then absorbed by the heat sink stem
via an intermediate thermal material.
[0012] The foregoing, and other features and advantages of the
invention, will be apparent from the following, more particular
description of the preferred embodiments of the invention, the
accompanying drawings, and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] For a more complete understanding of the present invention,
the objects and advantages thereof, reference is now made to the
ensuing descriptions taken in connection with the accompanying
drawings briefly described as follows:
[0014] FIG. 1 illustrates a sectional view of a conventional 360
degree lighting angle LED;
[0015] FIG. 2 illustrates an example of a spherical light producing
lens in accordance with one embodiment of the invention;
[0016] FIG. 3 is another iteration of the lens featuring a convex
crown;
[0017] FIG. 4 is another iteration of the lens featuring a convex
crown;
[0018] FIG. 5 is an iteration of the lens shown in FIG. 2 attached
to its corresponding heat sink structure;
[0019] FIG. 6A is a sectional view of the lens shown in FIG. 2,
featuring contact points and heat sink stem;
[0020] FIG. 6B is an iteration of the lens shown in FIG. 2, forming
a lens, LED and holder attachment with contact points;
[0021] FIG. 7A is a sectional view of the lens shown in FIG. 2,
featuring contact patches;
[0022] FIG. 7B is an iteration of the lens shown in FIG. 2, forming
a lens, LED and holder attachment with contact patches;
[0023] FIG. 8A is a sectional view of the lens in FIG. 2, featuring
a screw connection and heat sink stem with a screw connection;
[0024] FIG. 8B is an iteration of the lens shown in FIG. 2, forming
a lens, LED and holder attachment with a screw connection.
[0025] FIG. 9A is a sectional view of the lens shown in FIG. 2,
featuring positive and negative leads and heat sink stem with
positive and negative contact pads;
[0026] FIG. 9B is an iteration of the lens shown in FIG. 2, forming
a lens, LED and holder attachment with positive and negative
leads;
[0027] FIG. 10 features an LED device package of FIG. 5 adopted for
use in a conventional incandescent Edison bulb package; and
[0028] FIG. 11 features an LED device package of FIG. 5 adopted for
use in a conventional incandescent bulb with an indexed double
contact bayonet style base.
DETAILED DESCRIPTION OF EMBODIMENTS
[0029] Further features and advantages of the invention, as well as
the structure and operation of various embodiments of the
invention, are described in detail below with reference to the
accompanying FIGS. 2-11.
[0030] FIG. 2 illustrates an example of a spherical light producing
lens in accordance with one embodiment of the invention. Light rays
A through G emanating from an LED die 201, with a focal point 202,
are totally internally reflected then refracted out of the lens 200
by the pointed elements 203 through a 90 degree angle. The top
surface of the pointed elements 203 may be coated with a reflective
material such as aluminum (AL) or nickel chrome (NiCr). Light rays
G through J are refracted out of the double crown lens portion 204
through a 60 degree angle. Collectively, all the light rays emitted
by the LED die 201 radiate around a 300 degree lighting angle 205
in the vertical plane and a 360 degree lighting angle in the
horizontal plane. Surface 207 may be shaped to direct more light
rays emitted from the LED die 201 towards a particular section of
the lens, such as the pointed elements 203.
[0031] The length of the die 201 is directly proportional to the
size of the lens 200. The lens length (L) is 5.472 times the die
length, whereas the lens height (H) is 2 times the die length.
Thus, the lens 200 size may be scaled up or down in proportion to
the die length 201.
[0032] The lens 200 may be manufactured by a variety of process
including but not limited to injection molding, casting and diamond
etching. The lens 200 is made of a transparent material including
but not limited to acrylic; also known as Polymethylmethacrylate
(PMMA), polycarbonate (PC), polyetherimide (PEI) and cyclic olefin
copolymer (COC). The optimal refractive index range of the lens 200
is between 1.4 and 1.6.
[0033] The volume 206 between the lens and the LED die 201 may be
used to house a lens (not shown) mounted to the LED die 201 and
employed to direct more light emitted from the LED die 201 towards
a particular section of the lens, such as the pointed elements 203.
This volume 206 may also be filled with a transparent material
including but not limited to silicone, epoxy or any other material
with a refractive index of 1.4-1.6.
[0034] The lens 200 may also act as a color filter.
[0035] FIG. 3 illustrates another iteration of the lens 300 which
features a convex crown 304.
[0036] FIG. 4 illustrates a version of the lens 400 featuring a
concave crown 404.
[0037] FIG. 5 illustrates a sectional view of an LED device 500
where a lens 200 may be attached, fused or bonded to the top of the
heat sink stem 503. The LED die 201 is mounted on a silicon
substrate 501 (though other substrates may also be used).
Electricity powers the device by traveling from the positive lead
504 through the heat sink stem 503, across the bond wire 502 to the
LED chip 201. The negative lead 505 emerges from the heat sink slug
506. Besides the light that is produced (the propagation of which
is described in FIGS. 2-4) a significant amount of heat is also
generated by the LED die 201. Heat H1 is initially absorbed by the
heat sink slug 506 and then transferred to the heat sink stem 503.
The heat sink stem radiates heat away from the outer stem walls by
convection H2 and conducts the remainder of the heat H3 to a
prospective device. The heat sink stem 503, which can vary in
length and width, may be made of a non-electrically conductive
plastic material. This high thermal conductive plastic may be
injection molded. Another iteration of the heat sink stem is made
of metal.
[0038] FIG. 6B illustrates a lens 200 and LED lens holder 602 which
jointly form the lens and holder attachment 601.
[0039] FIG. 6A shows a sectional view of an LED device 600 which
illustrates the means by which the lens and holder attachment 601
is joined to the heat sink stem 603. The lens and holder attachment
601 is attached by means of two contact points 604 and 605. The
lens and holder attachment 601 is mounted atop the heat sink stem
603 and then rotated through a clockwise or a counterclockwise
rotation (depending on the design) until the positive contact point
604 and negative contact point 605 are locked into the positive
contact terminal 606 and negative contact terminal 607
respectively. A thermal interface material 608 reduces the thermal
resistance and increases the heat flow between the two bordering
surfaces; the heat sink slug 506 and the heat sink stem 603. The
thermal interface material 608 may include; thermally conductive
paste, thermally conductive compounds, Phase change material,
thermally conductive elastomers and thermally conductive tape.
[0040] FIG. 7B illustrates a lens 200 and LED lens holder 702 which
jointly form the lens and holder attachment 701. A positive 704 and
a negative contact patch 705 protrude from the base of the
attachment 701.
[0041] FIG. 7A shows a sectional view of an LED device 700 which
illustrates the means by which the lens and holder attachment 701
is joined to the heat sink stem 703. The lens and holder attachment
701 is attached by means of two contact points 708 and 709. The
lens and holder attachment 701 is mounted atop the heat sink stem
703 and then rotated through a clockwise or a counterclockwise
rotation (depending on the design) until the positive contact patch
704 and negative contact patch 705 are locked onto the positive
contact terminal 706 and negative contact terminal 707
respectively. A thermal interface material 608 may be used as a
heat conduit between the heat sink stem 703 and the heat sink slug
506.
[0042] FIG. 8B illustrates a lens 200 and LED lens holder 802 which
jointly form the lens and holder attachment 801. A positive contact
patch 804 circumscribes the base of the attachment 801.
[0043] FIG. 8A shows a sectional view of an LED device 800 which
illustrates the means by which the lens and holder attachment 801
is joined to the heat sink stem 803. The lens and holder attachment
801 is attached by a screw connection. The lens and holder
attachment 801 is mounted atop the heat sink stem 803 and rotated
through a clockwise or a counterclockwise rotation (depending on
the design) until the positive contact patch 804 and the heat sink
slug 506 are tightened and may be locked onto the positive contact
terminal 805 and the negative center pad 806 respectively.
[0044] An electrically conductive, thermal interface material may
be used as an interface between the negative center pad 806 and the
heat sink slug 506.
[0045] FIG. 9B illustrates a lens 200 and LED lens holder 902 which
jointly form the lens and holder attachment 901. A positive 904 and
a negative lead 905 extend out from the base of the attachment
901.
[0046] FIG. 9A shows a sectional view of an LED device 900 which
illustrates the means by which the lens and holder attachment 901
is joined to the heat sink stem 903. The positive LED lead 904 and
the negative LED lead 905 are soldered to the positive solder pad
906 and the negative solder pad 907 respectively. A thermal
interface material 608 may be used as a heat conduit between the
heat sink stem 903 and the heat sink slug 506.
[0047] FIG. 10 illustrates one variation of the LED device 500
adopted for use in a conventional incandescent Edison bulb package.
LED device packages 600 through 900 may also be used.
[0048] FIG. 11 illustrates another variation of the LED device 500
adopted for use in a conventional incandescent bulb with an indexed
double contact bayonet style base. LED device packages 600 through
900 may also be used.
[0049] The above described embodiments of the present invention are
meant to be illustrative and not limiting. It will thus be obvious
to those skilled in the art that various changes and modifications
may be made without departing from this invention in its broader
aspects. Therefore, the appended claims encompass all such changes
and modifications as falling within the spirit and scope of this
invention.
* * * * *