Synchronized light emitting diode backlighting systems and methods for displays

• US 20060221044A1
• Filed: 04/04/2005
• Published: 10/05/2006
• Est. Priority Date: 04/04/2005
• Status: Active Grant

• Current Assignee: Brightplus Ventures LLC (IPValuation Partners, LLC)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: van de Ven, Antony P., Negley, Gerald H.
• Granted Patent: US 7,358,954 B2
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2310/0237 Switching ON and OFF the backlight within one frame
• CPC Class Codes: G09G 2310/024 Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
• CPC Class Codes: G09G 2320/02 Improving the quality of display appearance
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127

Abstract

A display screen includes at least two arrays of at least two different color picture elements. A backlighting system for the display includes at least two arrays of Light Emitting Diode (LED) devices that are configured to radiate light of at least two colors in a light path that impinges on the display screen, to provide backlighting on the display screen. A synchronizer is configured to synchronously activate and deactivate at least a first one of the arrays of LED devices and at least a first one of the arrays of color picture elements. Different arrays of synchronously activated and deactivated LED devices and color picture elements also may be alternatingly synchronously activated and deactivated. The backlighting also may be pulsed.

Claims

1. A backlight system for a display screen that includes at least two arrays of a respective at least two different color picture elements, the backlight system comprising:

at least two arrays of Light Emitting Diode (LED) devices that are configured to radiate light of a respective at least two colors in a light path that impinges on the display screen to provide backlighting on the display screen; and

a synchronizer that is configured to synchronously activate and deactivate at least a first one of the arrays of LED devices and at least a first one of the arrays of color picture elements.

2. A backlight system according to claim 1 wherein the synchronizer is configured to synchronously activate and deactivate at least a first one of the arrays of LED devices and at least a first one of the arrays of color picture elements, and to alternatingly synchronously activate and deactivate at least a second one of the arrays of LED devices and at least a second one of the arrays of color picture elements.

3. A backlight system according to claim 1 wherein the synchronizer is configured to activate and deactivate the at least a first one of the arrays of LED devices multiple times in synchronism with a single activation and deactivation of the at least a first one of the arrays of color picture elements.

4. A backlight system according to claim 1 wherein the synchronizer is configured to pulse the at least a first one of the arrays of LED devices multiple times in synchronism with a single activation and deactivation of the at least a first one of the arrays of color picture elements.

5. A backlight system according to claim 1 wherein the display screen that includes at least two arrays of a respective at least two different color picture elements comprises an array of Liquid Crystal Display (LCD) devices including at least three color filters thereon.

6. A backlight system according to claim 5 wherein the array of LCD devices includes red, green and blue color filters thereon to provide red, blue and green color picture elements, wherein the at least two arrays of LED devices include arrays of red, green and blue LED devices and wherein the synchronizer is configured to synchronously activate the array of green picture elements and the array of green LED devices.

7. A backlight system according to claim 5 wherein the array of LCD devices includes red, green and blue color filters thereon to provide red, green and blue color picture elements, wherein the at least two arrays of LED devices include arrays of red, green and blue LED devices and wherein the synchronizer is configured to synchronously activate the array of blue picture elements and the array of blue LED devices.

8. A backlight system according to claim 5 wherein the array of LCD devices includes red, blue and green color filters thereon to provide red, green and blue color picture elements, wherein the at least two arrays of LED devices include arrays of red, green and blue LED devices and wherein the synchronizer is configured to synchronously activate and deactivate the array of blue LED devices and the array of blue color picture elements and to alternatingly synchronously activate and deactivate the array of green LED devices and the array of green color picture elements.

9. A backlight system according to claim 5 wherein the array of LCD devices includes red, blue and green color filters thereon to provide red, green and blue color picture elements, wherein the at least two arrays of LED devices include arrays of red, green, blue and cyanine LED devices and wherein the synchronizer is configured to synchronously activate and deactivate the arrays of green and blue LED devices and the arrays of green and blue color picture elements and to alternatingly synchronously activate and deactivate the array of cyanine LED devices and the arrays of red, green and blue color picture elements.

10. A backlight system according to claim 5 wherein the array of LCD devices includes red, blue and green color filters thereon to provide red, green and blue color picture elements, wherein the at least two arrays of LED devices include arrays of red, green, blue, cyanine and amber LED devices and wherein the synchronizer is configured to synchronously activate and deactivate the arrays of green and blue LED devices and the arrays of green and blue color picture elements and to alternatingly synchronously activate and deactivate the arrays of cyanine and amber LED devices and the arrays of red, green and blue color picture elements.

11. A backlight system according to claim 5 wherein the array of LCD devices includes red, blue and green color filters thereon to provide red, green and blue color picture elements, wherein the at least two arrays of LED devices include arrays of red, green, blue and cyanine LED devices and wherein the synchronizer is configured to synchronously activate and deactivate the array of green LED devices and the array of green color picture elements, to alternatingly synchronously activate and deactivate the array of blue LED devices and the array of blue color picture elements and to alternatingly synchronously activate and deactivate the array of cyanine LED devices and the arrays of red, green and blue color picture elements.

12. A backlight system according to claim 5 wherein the array of LCD devices includes red, blue and green color filters thereon to provide red, green and blue color picture elements, wherein the at least two arrays of LED devices include arrays of red, green, blue, cyanine and amber LED devices and wherein the synchronizer is configured to synchronously activate and deactivate the array of green LED devices and the array of green color picture elements, to alternatingly synchronously activate and deactivate the array of blue LED devices and the array of blue color picture elements and to alternatingly synchronously activate and deactivate the array of cyanine and amber LED devices and the arrays of red, green and blue color picture elements.

13. A display screen comprising at least three arrays of a respective at least two different color picture elements and a backlight system according to claim 1.

14. A display screen comprising an array of LCD devices including at least three color filters thereon and a backlight system according to claim 5.

15. A backlight system for a display screen that includes at least two arrays of a respective at least two different color picture elements, the backlight system comprising:

at least two arrays of different color light sources that are configured to radiate light of a respective at least two different colors in a light path that impinges on the display screen to provide backlighting on the display screen; and

a synchronizer that is configured to synchronously activate and deactivate at least a first one of the arrays of light sources and at least a first one of the arrays of color picture elements.

16. A backlight system according to claim 15 wherein the synchronizer is configured to synchronously activate and deactivate at least a first one of the arrays of light sources and at least a first one of the arrays of color picture elements and to alternatingly synchronously activate and deactivate at least a second one of the arrays of light sources and at least a second one of the arrays of color picture elements.

17. A backlight system according to claim 15 wherein the synchronizer is configured to activate and deactivate the at least a first one of the arrays of light sources multiple times in synchronism with a single activation and deactivation of the at least a first one of the arrays of color picture elements.

18. A backlight system according to claim 15 wherein the synchronizer is configured to pulse the at least a first one of the arrays of light sources multiple times in synchronism with a single activation and deactivation of the at least a first one of the arrays of color picture elements.

19. A display screen comprising the plurality of arrays of different color picture elements and a backlight system according to claim 15.

20. A method of increasing a color gamut of a display panel that includes a display screen comprising an array of Liquid Crystal Display (LCD) devices and at least two color filters thereon, and at least two arrays of Light Emitting Diode (LED) devices that are configured to radiate light of a respective at least two colors in a light path that impinges on the display screen to provide backlighting on the display screen, the method comprising:

synchronously activating and deactivating at least a first one of the arrays of LED devices and at least a first one of the arrays of color picture elements.

21. A method according to claim 20 wherein synchronously activating and deactivating comprises synchronously activating and deactivating at least a first one of the arrays of LED devices and at least a first one of the arrays of color picture elements and alternatingly synchronously activating and deactivating at least a second one of the arrays of LED devices and at least a second one of the arrays of color picture elements.

22. A method according to claim 20 wherein synchronously activating and deactivating comprises synchronously activating and deactivating the at least a first one of the arrays of LED devices multiple times in synchronism with a single activation and deactivation of the at least a first one of the arrays of color picture elements.

23. A method according to claim 20 wherein synchronously activating and deactivating comprises pulsing the at least a first one of the arrays of LED devices multiple times in synchronism with a single activation and deactivation of the at least a first one of the arrays of color picture elements.

24. A method according to claim 20 wherein the display screen that includes at least two arrays of a respective at least two different color picture elements comprises an array of Liquid Crystal Display (LCD) devices including at least three color filters thereon.

25. A method according to claim 24 wherein the array of LCD devices includes red, blue and green color filters thereon to provide red, green and blue color picture elements, wherein the at least two arrays of LED devices include arrays of red, green and blue LED devices and wherein synchronously activating and deactivating comprises synchronously activating and deactivating the array of green picture elements and the array of green LED devices.

26. A method according to claim 24 wherein the array of LCD devices includes red, blue and green color filters thereon to provide red, green and blue color picture elements, wherein the at least two arrays of LED devices include arrays of red, green and blue LED devices and wherein synchronously activating and deactivating comprises synchronously activating and deactivating the array of blue picture elements and the array of blue LED devices.

27. A method according to claim 24 wherein the array of LCD devices includes red, blue and green color filters thereon to provide red, green and blue color picture elements, wherein the at least two arrays of LED devices include arrays of red, green and blue LED devices and wherein synchronously activating and deactivating comprises synchronously activating and deactivating the array of blue LED devices and the array of blue color picture elements and alternatingly synchronously activating and deactivating the array of green LED devices and the array of green color picture elements.

28. A method according to claim 24 wherein the array of LCD devices includes red, blue and green color filters thereon to provide red, green and blue color picture elements, wherein the at least two arrays of LED devices include arrays of red, green, blue and cyanine LED devices and wherein synchronously activating and deactivating comprises synchronously activating and deactivating the arrays of green and blue LED devices and the arrays of green and blue color picture elements and alternatingly synchronously activating and deactivating the array of cyanine LED devices and the arrays of red, green and blue color picture elements.

29. A method according to claim 24 wherein the array of LCD devices includes red, blue and green color filters thereon to provide red, green and blue color picture elements, wherein the at least two arrays of LED devices include arrays of red, green, blue, cyanine and amber LED devices and wherein synchronously activating and deactivating comprises synchronously activating and deactivating the arrays of green and blue LED devices and the arrays of green and blue color picture elements and alternatingly synchronously activating and deactivating the arrays of cyanine and amber LED devices and the arrays of red, green and blue color picture elements.

30. A method according to claim 24 wherein the array of LCD devices includes red, blue and green color filters thereon to provide red, green and blue color picture elements, wherein the at least two arrays of LED devices include arrays of red, green, blue and cyanine LED devices and wherein synchronously activating and deactivating comprises synchronously activating and deactivating the array of green LED devices and the array of green color picture elements, alternatingly synchronously activating and deactivating the array of blue LED devices and the array of blue color picture elements and alternatingly synchronously activating and deactivating the array of cyanine LED devices and the arrays of red, green and blue color picture elements.

31. A backlight system according to claim 24 wherein the array of LCD devices includes red, blue and green color filters thereon to provide red, green and blue color picture elements, wherein the at least two arrays of LED devices include arrays of red, green, blue, cyanine and amber LED devices and wherein synchronously activating and deactivating comprises synchronously activating and deactivating the array of green LED devices and the array of green color picture elements, alternatingly synchronously activating and deactivating the array of blue LED devices and the array of blue color picture elements and alternatingly synchronously activating and deactivating the arrays of cyanine and amber LED devices and the arrays of red, green and blue color picture elements.

32. A backlight system for a display screen that includes an array of at least two different color picture elements, the backlight system comprising:

an array of pulsating Light Emitting Diode (LED) devices that are configured to radiate pulses of light in a light path that impinges on the display screen to provide backlighting on the display screen.

33. A display screen comprising an array of at least two different color picture elements and a backlight system according to claim 32.

34. A method of reducing image degradation of a display panel that includes a display screen comprising an array of at least two different color picture elements and an array of Light Emitting Diode (LED) devices that are configured to radiate light in a light path that impinges on the display screen to provide backlighting on the display screen, the method comprising:

pulsing the array of LED devices to radiate pulses of light in the light path that impinges on the display screen to provide pulsed backlighting on the display screen.