Multi-cavity LED array RGB collimation optic

• US 8,087,800 B2
• Filed: 10/01/2008
• Issued: 01/03/2012
• Est. Priority Date: 10/01/2007
• Status: Active Grant

• Current Assignee: Lamina Lighting, Inc., Lighting Science Group Corporation (Pegasus Capital Advisors, L.P.)
• Original Assignee: Lighting Science Group Corporation (Pegasus Capital Advisors, L.P.)
• Inventors: Bailey, Edward
• Primary Examiner(s): Alavi, Ali
• Application Number:
  US12/680,700
• Publication Number:
  US 20100238645A1
• Time in Patent Office: 1,189 Days
• Field of Search: 362244-246, 362/231, 362/268, 362305-310, 313/512
• US Class Current: 362/245
• CPC Class Codes: F21K 9/68 Details of reflectors forming part of the light source
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0066 in the form of an LED array

Abstract

This invention relates to optical devices. More specifically, the present invention relates to a collimated optical light source assembly that produces a uniform white light. Specifically, light from a multi-cavity RGB LED array is dispersed in a reflecting cavity having a Lambertian texture on the interior surface. The light is then emitted though a lenslet array and a cone lens which together further disperses the light emitted by the individual LEDs. The dispersed light is then collimated by a reflector.

Claims

1. An apparatus for producing collimated uniform white light, comprising:

a reflecting cavity having a predetermined reflective surface texture, configured to receive light from a light engine and to produce reflected light;

a micro-lenslet array disposed to receive at least a portion of the reflected light to produce a first dispersed light;

a concave lens disposed to receive at least a portion of the first dispersed light to produce a second dispersed light; and

a collimation reflector disposed to reflect at least a portion of the second dispersed light to produce collimated uniform white light.

2. The apparatus of claim 1, wherein the predetermined reflective surface texture of the reflecting cavity comprises at least one of:

a Lambertian scattering texture; and

, a Lambertian texture.

3. The apparatus of claim 2, wherein the Lambertian texture is configured to produce light that emerges from the top of the reflecting cavity at an approximately equal intensity in all radial angles around an axis of rotation of the reflecting cavity.

4. The apparatus of claim 1, wherein the reflecting cavity has comprises at least one of:

a vertical cross section shape selected from the group consisting of barrel spline shape and elliptical cross-sectional shape with truncated entrance and exit planes;

a vertical cross section shape matched to the beam width of the received light; and

, symmetry around the optical axis.

5. The apparatus of claim 1, wherein the micro-lenslet array is configured to produce intermediate micro-images.

6. The apparatus of claim 1, wherein the concave lens comprises at least one of:

a cone-shape; and

, a vertical cross-section shape of a revolved polynomial.

7. The apparatus of claim 1, wherein the collimation reflector has comprises at least one of:

a vertical cross-section shape of a revolved polynomial; and

, a confocal parabolic concentrator.

8. A system for producing collimated uniform white light, comprising:

a light engine;

a reflecting cavity having a predetermined reflective surface texture, configured to receive light from the light engine and to produce reflected light;

a micro-lenslet array disposed to receive at least a portion of the reflected light to produce a first dispersed light;

a concave lens disposed to receive at least a portion of the first dispersed light to produce a second dispersed light; and

a collimation reflector disposed to reflect at least a portion of the second dispersed light to produce collimated uniform white light.

9. The system of claim 8, wherein the light engine comprises an LED array disposed among a plurality of light-engine cavities.

10. The system of claim 9, wherein at least one primary direct emission LED is disposed within a central light-engine cavity of the plurality of light-engine cavities, and four LEDs of different primary wavelengths are disposed within at least one of a plurality of non-central light-engine cavities.

11. The system of claim 9, wherein a diode-pumped phosphor is disposed within at least a portion of the plurality of light-engine cavities.

12. The system of claim 9, wherein the light engine further comprises a reflector disposed between at least a portion of the plurality of light-engine cavities.

13. The system of claim 8, wherein the light engine has a beam width of approximately 60 degrees.

14. A method for producing collimated uniform white light, comprising the following steps:

emitting light using a plurality of LEDs disposed within a plurality of light-engine cavities;

reflecting at least a portion of the emitted light, using a reflecting cavity having a predetermined reflective surface texture, to produce a reflected light;

dispersing at least a portion of the reflected light, using a micro-lenslet array, to produce a first-dispersed light;

dispersing at least a portion of the first-dispersed light, using a concave lens, to produce a second-dispersed light; and

receiving at least a portion of the second-dispersed light, using a collimation reflector, to produce collimated uniform white light.

15. The method of claim 14, further comprising the steps of:

disposing at least one primary direct emission LED within a central light-engine cavity of the plurality of light-engine cavities; and

disposing four LEDs of different primary wavelengths within at least one of a plurality of non-central light-engine cavities.

16. The method of claim 14, wherein the step of emitting light further comprises emitting light having a beam width of approximately 60 degrees.

17. The method of claim 14, further comprising the step of reflecting light from between at least a first portion and a second portion of the plurality of light-engine cavities.

18. The method of claim 14, further comprising the step of converting the wavelength of light from within at least a portion of the plurality of light-engine cavities by use of a phosphor.

19. The method of claim 18, further comprising tuning the emitted light to a predetermined color by using a selected phosphor.

20. The method of claim 14, further comprising tuning the emitted light to a predetermined color by using one or more selected color LEDs.