Systems and methods for sampling light produced from an LED array

• US 8,723,426 B2
• Filed: 07/14/2011
• Issued: 05/13/2014
• Est. Priority Date: 07/15/2010
• Status: Expired due to Fees

• Current Assignee: Prism Projection, Inc.
• Original Assignee: Prism Projection, Inc.
• Inventors: Young, Garrett J.
• Primary Examiner(s): PHILOGENE, HAISSA
• Application Number:
  US13/183,120
• Publication Number:
  US 20120013255A1
• Time in Patent Office: 1,034 Days
• Field of Search: 315/117, 315/158, 315/294, 315/297, 315/307, 315/312, 315/318, 315/149, 362/297, 362/301, 362/330, 362/337, 362/511, 362/516, 362/544, 362/545, 362/555, 345/84, 345/88, 345/204, 345/690, 353/84
• US Class Current: 315/149
• CPC Class Codes: G01J 1/32 adapted for automatic variation of the measured or reference value regulation of light intensity G05D25/00
• CPC Class Codes: G01J 3/0205 Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
• CPC Class Codes: G01J 3/0267 Sample holders for colorimetry
• CPC Class Codes: H05B 45/12 using optical feedback

Abstract

A system may include an LED array, an optical plane, optics, a sensor and a controller. The LED array is configured to generate LED light. The optical plane has a plurality of scattering features and with a mixing chamber. The optics is configured to direct the LED light to the optical plane. The plurality of scattering features are configured to reflect a sampled portion of the LED light into the mixing chamber. The mixing chamber is configured to mix the sampled portion of the LED light. The sensor is configured to sense the sampled portion of the LED light received from the mixing chamber. The controller is connected to the sensor and configured to control the LED array using the sensed, sampled portion of the LED light received from the mixing chamber.

Claims

1. A method, comprising:

producing light from an LED array, wherein the LED array includes a plurality of LEDs;

directing the light from the LED array to an optical plate, wherein a substantial portion of the light directed to the optical plate passes through the optical plate;

sampling a portion of the light from the LED array, wherein sampling includes reflecting the sampled portion of the light into a mixing chamber, and mixing the sampled portion of the light within the mixing chamber, the optical plate having a cavity designed to function as the mixing chamber for the sampled portion of the light, wherein reflecting the sampled portion of the light includes using scattering features in the optical plate to reflect the sampled portion of the light into the mixing chamber; and

sensing the mixed, sampled portion of the light.

2. The method of claim 1, further comprising controlling the LED array using the sensed light.

3. The method of claim 2, wherein controlling the LED array includes individually controlling the intensity of individual LEDs in the LED array using the sensed light.

4. The method of claim 2, wherein controlling the LED array includes controlling the chromaticity of the light produced by the LEDs using the sensed light.

5. The method of claim 1, wherein mixing the light within the mixing chamber includes reflecting the light off of specular surfaces and diffuse surfaces of the mixing chamber.

6. The method of claim 1, wherein mixing the light within the mixing chamber includes reflecting the light off of specular surfaces of the mixing chamber.

7. The method of claim 1, wherein mixing the light within the mixing chamber includes reflecting the light off of diffuse surfaces of the mixing chamber.

8. A system, comprising:

an LED array configured to generate LED light;

an optical plane with a plurality of scattering features and with a mixing chamber;

optics configured to direct the LED light to the optical plane, wherein a substantial portion of the LED light passes through the optical plane, wherein the plurality of scattering features are configured to reflect a sampled portion of the LED light into the mixing chamber and wherein the mixing chamber is configured to mix the sampled portion of the LED light;

a sensor configured to sense the sampled portion of the LED light received from the mixing chamber; and

a controller connected to the sensor and configured to control the LED array using the sensed, sampled portion of the LED light received from the mixing chamber,

wherein the controller is configured to perform a testing routine to produce test light, wherein the scattering features are configured to reflect a sampled portion of the test light into the mixing chamber, the mixing chamber is configured to mix the sampled portion of the test light, the sensor is configured to sense the sampled portion of the test light, and the controller is configured to control the LED array using the sensed, sampled portion of the test light.

9. The system of claim 8, wherein the controller is configured to perform a testing routine where LEDs in individual subsets of the LED array produce the test light.

10. The system of claim 8, wherein the mixing chamber includes walls with specular reflection.

11. The system of claim 8, wherein the mixing chamber includes walls with diffuse reflection.

12. The system of claim 8, wherein the mixing chamber includes walls with both specular reflection and diffuse reflection.

13. The system of claim 8, wherein the controller is configured to perform a testing routine where all of the LEDs in the LED array produce the test light.

14. The system of claim 9, wherein the each individual subset of the LED array is a nominal color for LEDS in the LED array.

15. A system, comprising:

an LED array configured to generate LED light, wherein the LED array includes a plurality of LEDs;

an optical plane with a plurality of scattering features and with a mixing chamber;

optics configured to direct the LED light to the optical plane, wherein a substantial portion of the LED light passes through the optical plane, wherein the plurality of scattering features are configured to reflect a sampled portion of the LED light into the mixing chamber and wherein the mixing chamber is configured to mix the sampled portion of the LED light;

a sensor configured to sense the sampled portion of the LED light received from the mixing chamber; and

a controller connected to the sensor and configured to control the LED array using the sensed, sampled portion of the LED light received from the mixing chamber, the controller including;

a color module configured to receive data and convert the received data into a color space and determine an appropriate solution for producing a desired color using the LED array;

an LED control module configured to use the solution from the color module to control the plurality of LEDs in the LED array to produce the desired color; and

a color sensor module configured to measure chromaticity and intensity of the LED light, apply a sensor correction to measurements to create new measurements, and send the new measurements to the color module for use in determining subsequent solutions.

16. The system of claim 15, wherein the mixing chamber includes walls with specular reflection or diffuse reflection.

17. The system of claim 15, further comprising a cooling system configured to cool the light device, wherein the controller further includes a thermal control module configured to management temperature of the system.

18. The system of claim 15, wherein the color sensor module is configured to correct for LED temperature.

19. The system of claim 15, wherein the controller is configured to perform a testing routine where all of the LEDs in the LED array produce test light, wherein the scattering features are configured to reflect a sampled portion of the test light, the mixing chamber is configured to mix the sampled portion of the test light, and the sensor is configured to sense the sampled portion of the test light, and the controller is configured to control the LED array using the sensed, sampled portion of the test light.

20. The system of claim 15, wherein the controller is configured to perform a testing routine where LEDs in individual subsets of the LED array produce test light, wherein the scattering features are configured to reflect a sampled portion of the test light, the mixing chamber is configured to mix the sampled portion of the test light, and the sensor is configured to sense the sampled portion of the test light, and the controller is configured to control the LED array using the sensed, sampled portion of the test light.