LED illumination devices
A lens element has a curved surface mounted adjacent an LED for improving the light transmission efficiency and the dispersal pattern of radiation emitted by the LED.
1 . An illumination device, comprising:
an LED;
a lens element with a curved surface positioned opposite a light emitting surface of the LED; and
a quantity of transparent material joining the lens element and light emitting surface of the LED.
2 . The illumination device of claim 1 and further comprising a second lens element mounted adjacent the lens element positioned opposite the light emitting surface of the LED.
3 . The illumination device of claim 1 wherein the lens element is made of Cubic Zirconia.
4 . The illumination device of claim 1 wherein a distance between a light emitting surface of the LED and the curved surface of the lens element is less than about two times a longest dimension of the light emitting surface of the LED.
5 . The illumination device of claim 1 wherein the lens element is generally spherical and has a diameter greater than about three times a longest dimension of a light emitting surface of the LED.
6 . The illumination device of claim 1 wherein the lens element has an index of refraction greater than about 1.65 and the silicone gel has an index of refraction less than about 1.50.
7 . An illumination device, comprising:
a substrate;
a least one LED mounted on the substrate and having an exposed metal heat conduction surface;
at least one aperture formed in the substrate adjacent to the exposed metal heat conduction surface of the diode; and
a heat sink mounted in the aperture.
8 . The illumination device of claim 7 and further comprising a clamp structure for biasing the metal heat conduction surface against the heat sink.
9 . A method of fabricating an illumination device, comprising the steps of:
removing a top section of an optically transparent cover of a high intensity LED and lens assembly leaving a remaining lower section having a height dimension less than about twice a longest dimension of a light emitting surface of the LED; and
mounting a lens element on top of the lower section, the lens element having a curved surface that faces the light emitting surface of the LED.
10 . The method of claim 9 and further comprising the step of leaving a sufficient amount of transparent silicone gel to serve as an optical interface joining the light emitting surface and the generally spherical lens element.
11 . An illumination device, comprising:
a light emitting diode;
a generally spherical lens mounted adjacent to a light emitting surface face of the light emitting diode and positioned no further away from the light emitting surface than twice the longest dimension of the light emitting surface;
the spherical lens having an index of refraction relative to light emitted by the diode greater than about 1.65;
the spherical lens having a diameter greater than three times the longest dimension of the light emitting surface; and
a space between the spherical lens and the light emitting surface being filled with an intervening optically transparent material selected from the group consisting of fluid, grease, gel and elastomer having an index of refraction less than about 1.50.
12 . The illumination device of claim 11 , wherein the spherical lens is made of Cubic Zirconia.
13 . The illumination device of claim 11 , wherein the spherical lens is made of Sapphire.
14 . The illumination device of claim 11 , wherein the spherical lens is made of SF8 Optical Glass.
15 . The illumination device of claim 11 , wherein the intervening optically transparent material is silicone gel.
16 . The illumination device of claim 11 , wherein the intervening optically transparent material is silicone rubber.
17 . The illumination device of claim 11 wherein the spherical lens is press fit into a thermally conductive metal support structure.
18 . An illumination device, comprising:
a substrate;
a light emitting diode having an exposed metal heat conduction surface mounted on the substrate;
an aperture formed in the substrate adjacent to the metal heat conduction surface; and
heat sink means extending through the aperture for dissipating heat from the exposed diode metal heat conduction surface.
19 . The illumination device of claim 18 wherein the heat sink means is made of anodized Aluminum.
20 . The illumination device of claim 18 wherein the heat sink means is made of a material selected from the group consisting of Copper and Copper alloy.
21 . The illumination device of claim 18 wherein the heat sink means is made of an insulated Copper alloy.
22 . The illumination device of claim 18 wherein the heat sink means is made of a Copper alloy insulated with a diamond film.
23 . The illumination device of claim 18 and further comprising means for clamping the metal heat conduction surface against the heat sink means.
24 . The illumination device of claim 18 wherein the heat sink means includes an anodized Aluminum pin press fit into a second heat sink.
25 . The illumination device of claim 18 wherein the metal heat sink means includes an anodized Aluminum pin that extends into the aperture.
26 . An illumination device, comprising:
a surface mounted light emitting diode with an exposed metal heat conduction surface;
a heat sink; and
a spring clamp for holding the metal heat conduction surface against the heat sink.
27 . The illumination device of claim 26 wherein the spring clamp includes a metal disc spring.
28 . The illumination device of claim 26 wherein the spring clamp includes a Beryllium Copper metal disc spring.
29 . A illuminated device, comprising:
a light emitting diode;
a generally spherical lens element mounted adjacent to a light emitting surface of the light emitting diode;
the spherical lens element having an index of refraction relative to light emitted by the diode that is greater than about 1.65; and
a side of the spherical lens element opposite the light emitting surface being in contact with an optically transparent material with an index of refraction greater than about 1.20.
30 . The illumination device of claim 29 wherein the optically transparent material is water.
31 . The illumination device of claim 29 wherein the optically transparent material is mineral oil.
32 . The illumination device of claim 29 wherein the optically transparent material is a 3M Fluorinert™ fluid.
33 . The illumination device of claim 29 wherein the optically transparent material is a 3M Novec™ fluid.
34 . The illumination device of claim 29 wherein the optically transparent material is silicone rubber.
35 . The illumination device of claim 29 wherein the optically transparent material is silicone grease.
36 . The illumination device of claim 29 wherein the optically transparent material is polyurethane rubber.
37 . An illumination device, comprising:
a light emitting diode;
a spherical lens element mounted adjacent a light emitting surface of the light emitting diode;
the spherical lens element having an index of refraction relative to light emitted by the diode of greater than about 1.80; and
a negative focal length optical element placed in front of the spherical lens element to form the light into a beam having a predetermined shape.
38 . The illumination device of claim 37 wherein the negative optical element has a prismatic component to redirect the light beam off axis.
39 . The illumination device of claim 37 wherein the negative focal length optical element has a cylindrical component to change an aspect ratio of the light beam.
40 . A method of constructing an illumination device, comprising the steps of:
cutting off a section of an optically transparent cover that encapsulates a light emitting diode, leaving a remaining section above a light emitting surface of the diode no greater than twice the longest dimension of the light emitting surface; and
mounting a generally spherical Cubic Zirconia lens element having an index of refraction relative to the diode emitted light greater than about 1.65, and having a diameter greater than about three times the longest dimension of the light emitting surface.
41 . The method of constructing an illumination device of claim 40 wherein the optically transparent cover is made of silicone rubber.
42 . The method of constructing an illumination device of claim 40 wherein the optically transparent cover is made of a silicone rubber dome-like cover that encloses a silicone gel filled volume surrounding the light emitting diode.
43 . A method of controlling the output light pattern of a light emitting diode source, comprising the steps of:
using a Cubic Zirconia spherical lens element to converge the light from a light emitting diode; and
using a second diverging optical element to diverge the light by a predetermined amount.
44 . The method of claim 43 wherein the diverging optical element is a molded transparent plastic.
45 . The method of claim 43 wherein the diverging optical element is a molded acrylic plastic.
46 . The method of claim 43 wherein an aperture of predetermined size is placed between the Cubic Zirconia spherical lens element and the second diverging optical element to remove light from the edges of the beam.
47 . The method of claim 43 wherein a space between the spherical lens element and the diverging optical element is filled with a transparent incompressible material selected from the group consisting of fluid, grease, gel, elastomer and rubber-like material.
48 . The method of claim 46 wherein a space between the spherical lens element and the diverging optical element is filled with a transparent incompressible material from the group of fluid, grease, gel or elastomer or rubber-like material.
49 . An illumination device, comprising:
a light emitting diode;
a generally spherical lens element mounted adjacent a light emitting surface face of the light emitting diode and placed no further away from said light emitting surface than about twice the longest dimension of said light emitting surface;
the spherical lens element having an index of refraction relative to light emitted by the diode of greater than about 1.80 to converge the light to a focus;
the spherical lens element having a diameter greater than about three times the longest dimension of the light emitting surface;
a light path optical space between the spherical lens element and the light emitting surface being filled with an intervening optically transparent material selected from the group consisting of fluid, grease, gel elastomer and rubber-like material having an index of refraction less than about 1.60; and
an aperture placed approximately at a plane of focus smaller than a diameter of the spherical lens.
50 . The illumination device of claim 49 wherein the spherical lens element is made of Cubic Zirconia.
51 . An illumination device, comprising:
a light emitting diode;
a generally spherical lens element mounted adjacent to a light emitting surface face the light emitting diode and placed no further away from the light emitting surface than about twice a longest dimension of the light emitting surface;
the spherical lens element having an index of refraction relative to light emitted by the diode greater than about 1.80 to converge the light to a focus;
the spherical lens element having a diameter greater than about three times the longest dimension of the light emitting surface;
a light path optical space between the spherical lens element and the light emitting surface being filled with an intervening optically transparent material selected from the group consisting of fluid, grease, gel, elastomer or rubber-like material having an index of refraction less than about 1.60; and
a spacer to set the distance between the spherical lens element and the light emitting surface to a predetermined distance.
52 . The illumination device of claim 51 wherein the inside surface of the spacer is reflectorized.