Array of light emitting devices to produce a white light source

• US 20060105482A1
• Filed: 12/07/2005
• Published: 05/18/2006
• Est. Priority Date: 11/12/2004
• Status: Abandoned Application

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Lighting US LLC (Apollo Global Management, Inc.)
• Inventors: Krames, Michael R., Alferink, Robertus G.
• Application Number:
  US11/297,287
• Publication Number:
  US 20060105482A1
• Time in Patent Office: Days
• US Class Current: 438/22
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H05B 45/20 Controlling the colour of the light

Abstract

A device is provided with an array of a plurality of phosphor converted light emitting devices (LEDs) that produce broad spectrum light. The phosphor converted LEDs may produce light with different correlated color temperature (CCT) and are covered with an optical element that assists in mixing the light from the LEDs to produce a desired correlated color temperature. The phosphor converted LEDs may also be combined in an array with color LEDs. The color LEDs may be controlled to vary their brightness such that light with an approximately continuous broad spectrum is produced. By controlling the brightness of the color LEDs, light can be produced with a fixed brightness over a large range of white points with a high color rendering quality.

Claims

1. An apparatus comprising:

at least one phosphor converted light emitting device that produces light with a broad spectrum;

a plurality of color light emitting devices that produce light with a narrow spectrum; and

a controller for controlling the brightness of the light produced by the color light emitting devices, wherein the combination of the broad spectrum light produced by the at least one phosphor converted light emitting device and the narrow spectra light from the brightness controlled plurality of color light emitting devices produces a resulting spectrum that is more continuous than the broad spectrum produced by the at least one phosphor converted light emitting devices.

2. The apparatus of claim 1, further comprising a board, the at least one phosphor converted light emitting device and the plurality of color light emitting devices are mounted on the board.

3. The apparatus of claim 1, wherein there is a greater number of phosphor converted light emitting devices than color light emitting devices.

4. The apparatus of claim 3, wherein there is over twice as many phosphor converted light emitting devices as color light emitting devices.

5. The apparatus of claim 1, wherein the color light emitting devices produce blue, cyan, amber and red light.

6. The apparatus of claim 1, wherein the controller individually controls the brightness of the color light emitting devices to vary the correlated color temperature of the resulting spectrum.

7. A method comprising:

providing at least one phosphor converted light emitting device that produces light with a broad spectrum;

providing a plurality of color light emitting devices, each of which produces light with a narrow spectrum;

mixing the light produced by the at least one phosphor converted light emitting device and the plurality of color light emitting devices to produce light with a resulting spectrum that is more continuous than the broad spectrum produced by the at least one phosphor converted light emitting devices;

controlling the brightness of the light produced by the plurality of color light emitting devices to vary the correlated color temperature of the resulting spectrum.

8. The method of claim 7, further providing a board and mounting the at least one phosphor converted light emitting device and the plurality of color light emitting devices on the board.

9. The method of claim 7, wherein a greater number of phosphor converted light emitting devices are provided than color light emitting devices.

10. The method of claim 9, wherein over twice as many phosphor converted light emitting devices as color light emitting devices are provided.

11. The method of claim 7, wherein the color light emitting devices produce blue, cyan, amber and red light.

12. The method of claim 7, wherein the brightness of the light produced by each color light emitting device is controlled separately to vary the correlated color temperature.

13. The method of claim 7, wherein the brightness of each different colored light produced by the color light emitting devices is controlled separately to vary the correlated color temperature.

14. A method comprising:

providing a plurality of phosphor converted light emitting devices that produce light with a broad spectrum, the phosphor converted light emitting devices producing light with different correlated color temperature;

arranging the plurality of phosphor converted light emitting devices in an array; and

covering the array of phosphor converted light emitting devices with an optical element that assists mixing of the light with different correlated color temperatures to produce light with a desired correlated color temperature.

15. The method of claim 14, wherein the optical element is bonded to the phosphor converted light emitting devices.

16. The method of claim 14, wherein the optical element is a dome mounted over the phosphor converted light emitting devices and filled with an encapsulant.

17. The method of claim 14, wherein arranging the plurality of phosphor converted light emitting devices comprises mounting the plurality of phosphor converted light emitting devices to a board.

18. The method of claim 14, the method further comprising:

providing a plurality of color light emitting devices, each of which produces light with a narrow spectrum;

arranging the plurality of color light emitting devices in the array with the plurality of phosphor converted light emitting devices.

19. The method of claim 18, further comprising controlling the brightness of the light produced by the plurality of color light emitting devices to vary the correlated color temperature of the resulting spectrum.

20. An apparatus that produces broadband light with a desired correlated color temperature, the apparatus comprising:

an array of a plurality of phosphor converted light emitting devices that produce light with a broad spectrum with different correlated color temperatures; and

an optical element disposed over the array of the plurality of phosphor converted light emitting devices, the optical element mixing the light with different correlated color temperatures to produce light with the desired correlated color temperature.

21. The apparatus of claim 20, wherein the optical element is bonded to the phosphor converted light emitting devices.

22. The apparatus of claim 20, wherein the optical element is a dome mounted over the phosphor converted light emitting devices and filled with an encapsulant.

23. The apparatus of claim 20, further comprising a board to which the array of the plurality of phosphor converted light emitting devices is mounted.

24. The apparatus of claim 20, wherein the array further comprises a plurality of color light emitting devices.

25. The apparatus of claim 24, the apparatus further comprising a controller for controlling the brightness of the light produced by the plurality of color light emitting devices to vary the correlated color temperature to the desired correlated color temperature.