Independent control of light emitting diodes for backlighting of color displays

• US 20070019129A1
• Filed: 07/20/2005
• Published: 01/25/2007
• Est. Priority Date: 07/20/2005
• Status: Abandoned Application

• Current Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Negley, Gerald
• Application Number:
  US11/185,397
• Publication Number:
  US 20070019129A1
• Time in Patent Office: Days
• US Class Current: 349/61
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 3/32 semiconductive, e.g. using light-emitting diodes [LED]
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix

Abstract

Backlighting systems for color display screens include clusters of LED devices of different colors that are configured to radiate the different colors in a light path that impinges on the color display screen, to provide backlighting on the color display screen. LED device controllers are provided, a respective one of which is configured to control operating parameters of a subset of the clusters of LED devices, a single cluster of LED devices and/or individual LED devices in the individual clusters. The LED device controllers may use a common data line.

Claims

1. A backlight system for a color display screen that includes an array of color picture elements, the backlight system comprising:

a plurality of clusters of Light Emitting Diode (LED) devices of different colors that are configured to radiate light of the different colors in a light path that impinges on the color display screen to provide backlighting on the color display screen; and

a plurality of LED device controllers, a respective one of which is configured to control operating parameters of a subset of the clusters of LED devices.

2. A backlight system according to claim 1 wherein a respective LED device controller is configured to control the operating parameters of a respective single cluster of LED devices.

3. A backlight system according to claim 2 wherein a respective LED device controller is configured to control the operating parameters of individual LED devices of different colors in a respective single cluster of LED devices.

4. A backlight system according to claim 2 wherein a respective cluster of LED devices comprises a red, a blue and a green LED device, wherein the plurality of LED device controllers comprise a plurality of LED device controller integrated circuits and wherein a respective cluster comprising a red, a blue and a green LED device is mounted on a respective LED device controller integrated circuit.

5. A backlight system according to claim 4 further comprising a mounting substrate, wherein the plurality of LED device controller integrated circuits are mounted on the mounting substrate.

6. A backlight system according to claim 4 wherein at least some of the LED controller integrated circuits are electrically connected to a common data line.

7. A backlight system according to claim 4 further comprising a reflector between a respective cluster comprising a red, a blue and a green LED device and a respective LED device controller integrated circuit.

8. A backlight system according to claim 2 wherein a respective cluster of LED devices comprises a red, a blue and a green LED device, wherein the plurality of LED device controllers comprise a plurality of LED device controller integrated circuits and wherein a respective cluster comprising a red, a blue and a green LED device and a respective LED device controller integrated circuit are mounted on a common substrate.

9. A backlight system according to claim 8 further comprising a mounting substrate, wherein a plurality of the common substrates are mounted on the mounting substrate.

10. A backlight system according to claim 8 wherein the common substrate comprises a reflector adjacent the cluster of LED devices.

11. A backlight system according to claim 8 wherein at least some of the LED controller integrated circuits are electrically connected to a common data line.

12. A backlight system according to claim 1 wherein the plurality of LED device controllers are configured to control operating parameters of the clusters of LED devices to provide uniform backlighting by compensating for electrical/optical parameter differences among the LED devices.

13. A backlight system according to claim 1 wherein the plurality of LED device controllers are configured to control operating parameters of the clusters of LED devices to provide a desired color point of the backlighting by compensating for electrical/optical parameter differences among the LED devices.

14. A backlight system according to claim 1 in combination with the color display screen that includes the array of color picture elements.

15. A backlight system according to claim 14 wherein the array of color picture elements comprises an array of color Liquid Crystal Display (LCD) picture elements.

16. A backlighting method for a color display screen that includes an array of color picture elements and a plurality of clusters of Light Emitting Diode (LED) devices of different colors that are configured to radiate light of the different colors in a light path that impinges on the color display screen to provide backlighting on the color display screen, the backlighting method comprising:

independently controlling operating parameters of subsets of the clusters of LED devices during operation thereof.

17. A backlighting method according to claim 16 wherein independently controlling operating parameters of subsets of the clusters of LED devices during operation thereof comprises independently controlling operating parameters of individual clusters of LED devices during operation thereof.

18. A backlighting method according to claim 17 wherein independently controlling operating parameters of individual clusters of LED devices during operation thereof comprises independently controlling operating parameters of individual LED devices of different colors in the individual clusters of LED devices during operation thereof.

19. A backlighting method according to claim 16 wherein independently controlling operating parameters of subsets of the clusters of LED devices during operation thereof is performed using a common data line for at least one subset of the clusters of LED devices.

20. A backlighting method according to claim 16 wherein independently controlling operating parameters of subsets of the clusters of LED devices during operation thereof comprises independently controlling operating parameters of subsets of the clusters of LED devices during operation thereof to provide uniform backlighting by compensating for electrical/optical parameter differences among the LED devices.

21. A backlighting method according to claim 16 wherein independently controlling operating parameters of subsets of the clusters of LED devices during operation thereof comprises independently controlling operating parameters of subsets of the clusters of LED devices during operation thereof to provide a desired color point of the backlighting by compensating for electrical/optical parameter differences among the LED devices.

22. A backlight system for a color display screen that includes an array of color picture elements, the backlight system comprising:

a plurality of clusters of Light Emitting Diode (LED) devices of different colors that are configured to radiate light of the different colors in a light path that impinges on the color display screen to provide backlighting on the color display screen; and

an LED device controller that is configured to independently control operating parameters of subsets of the clusters of LED devices.

23. A backlight system according to claim 22 wherein the LED device controller is configured to independently control the operating parameters of individual clusters of LED devices.

24. A backlight system according to claim 23 wherein the LED device controller is further configured to independently control the operating parameters of individual LED devices in individual clusters of LED devices.

25. A backlight system according to claim 22 wherein a respective cluster of LED devices comprises a red, a blue and a green LED device.

26. A backlight system according to claim 22 wherein the LED device controller is configured to independently control the operating parameters of individual clusters of LED devices via a common data line.

27. A backlight system according to claim 22 wherein the LED device controller is configured to control operating parameters of the clusters of LED devices to provide uniform backlighting notwithstanding electrical/optical parameter differences among the LED devices.

28. A backlight system according to claim 22 wherein the LED device controller is configured to control operating parameters of the clusters of LED devices to provide a desired color point of the backlighting notwithstanding electrical/optical parameter differences among the LED devices.

29. A backlight system according to claim 22 in combination with the color display screen that includes the array of color picture elements.