Apparatus and methods for combining light emitters

• US 8,513,871 B2
• Filed: 12/14/2012
• Issued: 08/20/2013
• Est. Priority Date: 03/28/2008
• Status: Active Grant

• Current Assignee: CREE Led Incorporated (Smart Global Holdings Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: You, Chenhua, Roberts, John K.
• Primary Examiner(s): VU, DAVID HUNG
• Application Number:
  US13/714,955
• Publication Number:
  US 20130107515A1
• Time in Patent Office: 249 Days
• Field of Search: 315/312, 315/291, 315/294, 362/253, 362/230, 362/231, 362/234, 362/235, 362/237, 362/236, 313/498, 313/503, 313/501, 313/502
• US Class Current: 313/498
• CPC Class Codes: F21V 9/20 Dichroic filters, i.e. devices operating on the principle of wave interference to pass specific ranges of wavelengths while cancelling others
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 5/026 Control of mixing and/or overlay of colours in general G09G5/022 and G09G5/024 take precedence
• CPC Class Codes: H05B 45/00 Circuit arrangements for operating light-emitting diodes [LED]
• CPC Class Codes: H05B 45/20 Controlling the colour of the light

Abstract

Provided are methods and apparatus for combining light emitters and devices including the same. Embodiments include methods of selecting combinations of multiple light emitters that are grouped into multiple bins. The multiple bins correspond to multiple emitter group regions in a multiple axis color space and multiple luminosity ranges. Such methods may include prioritizing multiple combinations of light emitters from at least two of the bins, each of the combinations including chromaticity values corresponding to a desired color region and a luminosity value corresponding to a specified luminosity range.

Claims

1. A method of selecting combinations of a plurality of light emitters, the method comprising:

grouping the plurality of emitters into a plurality of bins corresponding to a plurality of emitter group regions in a multiple axis color space and a plurality of luminosity ranges, each of the plurality of emitter group regions defining a range of chromaticities distinct from chromaticities of other of the plurality of emitter group regions, each of the plurality of bins corresponding to a different combination of one of the plurality of luminosity ranges and one of the plurality of emitter group regions;

determining a plurality of chromaticities corresponding to a center point in each of the plurality of emitter group regions, each of the plurality of chromaticities including a plurality of chromaticity component values corresponding to the multiple axis color space;

defining a desired color region in the multiple axis color space;

estimating a combined chromaticity corresponding to a combination center point for each of a plurality of N-bin combinations, N defining the number of the plurality of bins that are combined to estimate each of the combination center points;

estimating a combined luminosity corresponding to the combination center point for each of the plurality of N-bin combinations;

comparing the combined chromaticity of each of the plurality of combination center points to the desired color region; and

selecting combinations of the plurality of light emitters responsive to comparing the combined chromaticity of each of the plurality of combination center points to the desired color region.

2. The method of claim 1, further comprising:

comparing the combined luminosity of each of the plurality of combination center points to a specified luminosity range; and

selecting combinations of the plurality of light emitters responsive to comparing the combined luminosity of each of the plurality of combination center points.

3. The method of claim 2, further comprising discarding a non-compliant portion of the plurality of combination center points that are not within the specified luminosity range.

4. The method of claim 1, further comprising discarding a non-compliant portion of the plurality of combination center points that are not within the desired color region.

5. The method of claim 1, wherein N comprises two and estimating the combined chromaticity and luminosity corresponding to each of the plurality of combination center points comprises estimating the combined chromaticity and luminosity for two-emitter group region combinations.

6. The method of claim 1, further comprising:

identifying a portion of the plurality of bins that include center point chromaticities that are substantially different from a target chromaticity point in the desired color region; and

ranking the identified portion of the plurality of bins at a high matching priority relative to other of the plurality of bins.

7. The method of claim 1, further comprising prioritizing each of the plurality of combination center points as a function of corresponding ones of the plurality of bins.

8. The method of claim 7, wherein prioritizing comprises ranking the plurality of combination center points corresponding to a difference between a bin center point included in the combination center point and a target chromaticity point.

9. The method of claim 1, further comprising prioritizing each of the plurality of combination center points corresponding to a difference between ones of the plurality of combination center points and a target chromaticity point.

10. The method of claim 9, further comprising estimating the target chromaticity point as an inventory chromaticity center point that is based on an emitter inventory that includes the plurality of light emitters.

11. The method of claim 10, wherein estimating the target chromaticity point comprises estimating the inventory chromaticity center point corresponding to an aggregate chromaticity and luminosity of light emitters in the emitter inventory.

12. The method of claim 9, wherein prioritizing the plurality of combination center points further comprises ranking ones of the plurality of combination center points corresponding to a distance to the target chromaticity point in the multiple axis color space.

13. The method of claim 9, wherein prioritizing the plurality of combination center points further comprises ranking ones of the plurality of combination center points corresponding to a plurality of concentric regions centered at the target chromaticity point, the regions including an aspect ratio substantially similar to an aspect ratio of ones of the plurality of emitter group regions.

14. The method of claim 9, wherein prioritizing the plurality of combination center points further comprises ranking ones of the plurality of combination center points corresponding to a plurality of concentric regions centered at the target chromaticity point, the regions including an aspect ratio substantially similar to an aspect ratio of a bounded area corresponding to distribution data of emitter inventory bin data.

15. The method of claim 1, further comprising prioritizing the plurality of bins corresponding to a difficulty in combining emitters in each of the plurality of bins relative to other ones of the plurality of bins.

16. The method of claim 15, wherein the difficulty in combining emitters in each of the plurality of bins corresponds to distribution data of the plurality of light emitters relative to the plurality of bins.

17. The method of claim 1,

wherein the multiple axis color space comprises International Commission on Illumination (CIE) 1931 that expresses a chromaticity as an ordered pair x, y and luminosity as Y,

wherein a first emitter group region center point is represented by x1, y1, and Y1 and a second emitter group region center point is represented by x2, y2, and Y2,

wherein a combination center point is expressed as x, y, and Y,

wherein x and y are each functions of x1, y1, Y1, x2, y2, and Y2, and

wherein Y is a function of Y1 and Y2.

18. A computer program product for selecting combinations of a plurality of light emitters, the computer program product comprising a computer usable storage medium having computer readable program code embodied in the medium, the computer readable program code configured to carry out the method of claim 1.