Color control of light emitting devices and applications thereof

• US 9,468,070 B2
• Filed: 02/16/2010
• Issued: 10/11/2016
• Est. Priority Date: 02/16/2010
• Status: Active Grant

• Current Assignee: IDEAL Industries Lighting, LLC (Ideal Industries Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: McClear, Mark, Thieken, Paul
• Primary Examiner(s): PHAM, THAI N
• Application Number:
  US12/706,370
• Publication Number:
  US 20110199019A1
• Time in Patent Office: 2,429 Days
• Field of Search: 315/185.R, 315/186, 315/192, 315/291, 315/294, 315/295, 315/297, 315/312, 313/498, 313/501, 313/502, 313/503, 362/227, 362/230, 362/231, 362/249.02, 362/800
• US Class Current: 1/1
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/28 using temperature feedback
• CPC Class Codes: H05B 45/46 having LEDs disposed in parallel lines
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

The present invention, in one aspect, provides light emitting devices comprising LEDs, the light emitting devices, in some embodiments, having a simplified architecture for controlling the color of emitted light.

Claims

1. A light emitting device comprising:

a plurality of first LEDs; and

a plurality of second LEDs;

light output of the light emitting device falling within a first chromaticity region at one or more first operating parameters; and

electrical circuitry including one or more drivers or current controllers for providing a first adjusted drive current of predetermined value to the plurality of first LEDs and a second drive current to the plurality of second LEDs to provide the light output of the light emitting device falling within a defined second chromaticity region;

wherein the predetermined value of the first adjusted drive current is based on binning of the first LEDs; and

wherein a ratio of the first adjusted drive current to the second drive current ranges from 0.7 to 1.3.

2. The light emitting device of claim 1, wherein the defined second chromaticity region approximates a 7-step MacAdam ellipse.

3. The light emitting device of claim 1, wherein the defined second chromaticity region approximates a 4-step MacAdam ellipse.

4. The light emitting device of claim 1, wherein the predetermined value of the first adjusted drive current is listed on a reference guide for the light emitting device.

5. The light emitting device of claim 4, wherein the reference guide is stored in an electronic format for electronic communication with a driver or current controller of the first LEDs.

6. The light emitting device of claim 1 further comprising a light output control apparatus, wherein sensors of the light output control apparatus consist of non-optical detectors.

7. The light emitting device of claim 6, wherein the non-optical detector is a thermistor, thermocouple, timer or a combination thereof.

8. The light emitting device of claim 1, wherein the predetermined value of the first adjusted drive current is further based on one or more second operating parameters of the light emitting device, including operating temperature of the first and second LEDs in the defined second chromaticity region.

9. The light emitting device of claim 1, wherein the predetermined value of the first adjusted drive current value ranges from 20 mA to 700 mA.

10. The light emitting device of claim 1, wherein the first chromaticity region and the defined second chromaticity region do not overlap.

11. The light emitting device of claim 1, wherein the defined second chromaticity region overlaps with one or more bins defined in ANSI C78.377A.

12. The light emitting device of claim 1, wherein the defined second chromaticity region is a quadrangle on the CIE 1931 Chromaticity Diagram.

22. The light emitting device of claim 1, wherein the predetermined value of the first drive current is further based on binning of the second LEDs.

13. A method of controlling the color of light emitted from a light emitting device comprising:

defining a second chromaticity region;

providing a plurality of first LEDs;

providing a plurality of second LEDs, wherein light output of the light emitting device falls within a first chromaticity region at a first drive current for the first LEDs and a second drive current for the second LEDs;

selecting a first adjusted drive current of predetermined value for the first LEDs to achieve a light output from the light emitting device falling within the defined second chromaticity region, wherein the predetermined value is based on binning of the first LEDs; and

supplying the first adjusted drive current to the plurality of first LEDs to provide light from the light emitting device in the defined second chromaticity region, wherein the first adjusted drive current and second drive current are supplied by electrical circuitry comprising one or more drivers or current controllers and a ratio of the first adjusted drive current to the second drive current ranges from 0.7 to 1.3.

14. The method of claim 13, wherein the predetermined value of the first adjusted drive current is further based on binning of the second LEDs.

15. The method of claim 13, wherein the predetermined value of the first adjusted drive current is further based on one or more second operating parameters of the light emitting device, including operating temperature of the first and second LEDs in the defined second chromaticity region.

16. The method of claim 13, wherein the first chromaticity region and the defined second chromaticity region do not overlap.

17. The method of claim 13, wherein the defined second chromaticity region is a quadrangle on the CIE 1931 Chromaticity Diagram.

18. The method of claim 13, wherein the predetermined value of the first adjusted drive current value ranges from 20 mA to 700 mA.

19. The method of claim 13, wherein the predetermined value of the first adjusted drive current is selected from a reference guide.

20. The method of claim 19, wherein the reference guide is stored in an electronic format for electronic communication with a driver or current controller of the first LEDs.

21. The method of claim 13, wherein the first LEDs and the second LEDs have non-overlapping emission spectra.

23. A light emitting device comprising:

a plurality of first LEDs; and

a plurality of second LEDs;

light output of the light emitting device falling within a first chromaticity region at one or more first operating parameters; and

electrical circuitry including one or more drivers or current controllers for providing a first adjusted drive current of predetermined value to the plurality of first LEDs and a second drive current to the plurality of second LEDs to provide the light output of the light emitting device falling within a defined second chromaticity region;

wherein the predetermined value of the first adjusted drive current is based on one or more second operating parameters of the light emitting device, including operating temperature of the first and second LEDs in the defined second chromaticity region and a ratio of the first adjusted drive current to the second drive current ranges from 0.7 to 1.3.

24. The light emitting device of claim 23, wherein the operating temperature is the solder point temperature of the first and second LEDs.

25. The light emitting device of claim 24, wherein the solder point temperature ranges from 50°

C. to 85°

C.

26. The light emitting device of claim 23, wherein the defined second chromaticity region overlaps with one or more bins defined by ANSI C78.377A.

27. The light emitting device of claim 23, wherein the defined chromaticity region is a quadrangle on the CIE 1931 Chromaticity diagram.

28. The light emitting device of claim 23, wherein the predetermined value of the first adjusted drive current value ranges from 20 mA to 700 mA.

29. The light emitting device of claim 23, wherein the first chromaticity region and defined second chromaticity region do not overlap.