LED illumination devices and methods
Lens elements having a generally curved shape with a flat surface mounted adjacent an LED for improving the light transmission efficiency and the dispersal pattern of radiation emitted by the LED are disclosed.
1. An LED illumination device, comprising:
a light emitting diode (LED);
a generally curved lens having a flat surface positioned adjacent to a light emitting surface face of the LED; wherein the lens has an index of refraction relative to a light wavelength emitted by the LED of greater than about 1.65;
a thermal cup comprising a hollow post;
a circuit board comprising a hole, wherein the hole is disposed to receive the hollow post, wherein the circuit board is configured to move along an axis that is parallel to a surface of the circuit board;
a spring disposed around the hollow post; and
a wire, wherein a first end of the wire is connected to the light emitting diode, wherein a second end of the wire is connected to the circuit board, and wherein the wire passes through the hollow portion of the hollow post.
2. The illumination device of claim 1 , further comprising:
a thermally conductive fluid disposed in a channel, wherein at least a portion of the thermally conductive fluid is in contact with at least a portion of the hemispherical lens.
3. The illumination device of claim 1 , wherein one or more outer surfaces of the hemispherical shaped lens comprise a curved surface and the flat surface, and wherein the flat surface of the hemispherical shaped lens is in contact with the light emitting surface face of the light emitting diode.
4. The illumination device of claim 1 , wherein the flat surface of the hemispherical shaped lens is positioned within a predetermined distance from the light emitting surface face of the light emitting diode, the predetermined distance being less than or equal to a diameter of the hemispherical shaped lens.
5. The illumination device of claim 1 , further comprising an intervening optically transparent material comprising one or more of fluid, grease, gel, and elastomer having an index of refraction of less than about 1.50, the material filling a space between the flat surface of the hemispherical lens and the light emitting surface face of the light emitting diode.
6. The illumination device of claim 1 , further comprising:
an acrylic window positioned adjacent to the hemispherical shaped lens;
an intervening optically transparent material, the intervening optically transparent material filling a space between at least a portion of a curved surface of the hemispherical shaped lens and the acrylic window, wherein the acrylic window has an index of refraction greater than about 1.20.
7. The illumination device of claim 1 , wherein the generally hemispherical shaped lens has a diameter greater than three times the longest dimension of the light emitting surface face of the light emitting diode.
8. The illumination device of claim 1 , wherein the generally hemispherical shaped lens comprises a cubic zirconia material.
9. The illumination device of claim 1 , wherein the generally hemispherical shaped lens comprises a sapphire material.
10. The illumination device of claim 1 , further comprising a heat sink thermally coupled to a heat conduction surface of the LED.