Partially filterless liquid crystal display devices and methods of operating the same

• US 7,952,544 B2
• Filed: 02/15/2007
• Issued: 05/31/2011
• Est. Priority Date: 02/15/2007
• Status: Active Grant

• Current Assignee: CREE Led Incorporated (Smart Global Holdings Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Roberts, John
• Primary Examiner(s): Shankar, Vijay
• Application Number:
  US11/675,250
• Publication Number:
  US 20080198112A1
• Time in Patent Office: 1,566 Days
• Field of Search: 345 87-102, 345204-215
• US Class Current: 345/87
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources

Abstract

A liquid crystal display (LCD) device includes a backlight configured to emit first, second, and/or third colors of light, and a backlight controller. The backlight controller is configured to activate the backlight to simultaneously emit the first and second colors of light to generate a first image component including a combination of first color image data and second color image data, and to separately emit the third color of light at a different time than the first and second colors of light to generate a second image component including third color image data. The LCD device is configured to display the first and second image components to provide a single image frame. Related devices and methods of operation are also discussed.

Claims

1. A liquid crystal display (LCD) device, comprising:

a backlight configured to emit first, second, and third colors of light; and

a backlight controller configured to activate the backlight to simultaneously emit the first and second colors of light to generate a first image component including a combination of first color image data and second color image data, and to separately emit the third color of light at a different time than the first and second colors of light to generate a second image component including third color image data; and

a pixel array including a plurality of pixels configured to sequentially display the first and second image components to provide the image, wherein the plurality of pixels respectively comprise;

a first subpixel configured to display the first color image data, the first subpixel including a first liquid crystal shutter configured to be activated to an open position and a closed position, and a first color filter configured to allow passage of the first color of light and prevent passage of the second color of light;

a second subpixel configured to display the second color image data, the second subpixel including a second liquid crystal shutter configured to be activated to an open position and a closed position, and a second color filter configured to allow passage of the second color of light and prevent passage of the first color of light; and

a third subpixel configured to display the third color image data, the third subpixel including a third liquid crystal shutter configured to be activated to an open position and a closed position, wherein the third subpixel is configured to allow passage of the first and/or second colors of light in the open position,

wherein the LCD device is configured to display the first and second image components to provide a single image frame.

2. The device of claim 1,

wherein the third subpixel does not include a color filter.

3. The device of claim 2, further comprising:

a shutter controller configured to selectively activate the first and second liquid crystal shutters to the open position and activate the third liquid crystal shutter to the closed position to generate the first image component, and configured to selectively activate the third liquid crystal shutter to the open position to generate the second image component.

4. The device of claim 3, wherein the shutter controller is configured to activate the third liquid crystal shutter to the closed position when the backlight is activated to simultaneously emit the first and second colors of light to prevent passage of the first and second colors of light.

5. The device of claim 4, wherein the shutter controller is further configured to selectively activate the first and second liquid crystal shutters to the open position when the backlight is activated to simultaneously emit the first and second colors of light to combine the first color image data and the second color image data.

6. The device of claim 3, wherein the shutter controller is configured to selectively activate the third liquid crystal shutter to the open position when the backlight is activated to emit the third color of light to allow passage of the third color of light.

7. The device of claim 6, wherein the shutter controller is further configured to activate the first and second liquid crystal shutters to the closed position when the backlight is activated to emit the third color of light.

8. The device of claim 7, wherein the first and second color filters are configured to allow passage of the third color of light.

9. The device of claim 6, wherein the first and second color filters are further configured to prevent passage of the third color of light, and wherein the shutter controller is further configured to activate the first and/or second liquid crystal shutters to the open position when the backlight is activated to emit the third color of light.

10. The device of claim 3, wherein the first and second color filters are further configured to prevent passage of the third color of light, and wherein the backlight controller is configured to simultaneously emit the first, second, and third colors of light to generate the first image component.

11. The device of claim 2, wherein the backlight controller is configured to alternately activate the backlight to emit the first and second colors of light simultaneously and activate the backlight to emit the third color of light at a different time than the first and second colors of light based on a shutter rate of the first, second, and/or third liquid crystal shutters.

12. The device of claim 1, wherein the backlight comprises a solid state lighting panel comprising:

a first solid state lighting element configured to emit the first color of light;

a second solid state lighting element configured to emit the second color of light; and

a third solid state lighting element configured to emit the third color of light;

wherein the backlight controller is configured to activate the first and second solid state lighting elements substantially simultaneously to generate the first image component, and to activate the third solid state lighting element at a different time than the first and second solid state lighting elements to generate the second image component.

13. The device of claim 1, wherein a wavelength of the third color of light is greater than a wavelength of the second color of light but less than a wavelength of the first color of light.

14. The device of claim 13, wherein the first color of light comprises red light, wherein the second color of light comprises blue light, and wherein the third color of light comprises green light.

15. The device of claim 1, wherein the first color of light comprises blue light, wherein the second color of light comprises green light, and wherein the third color of light comprises red light.

16. The device of claim 1, wherein the first color of light comprises green light, wherein the second color of light comprises red light, and wherein the third color of light comprises blue light.

17. A screen for use in a liquid crystal display (LCD) device, comprising:

a pixel array including a plurality of pixels configured to display an image, wherein the plurality of pixels respectively comprise;

a first subpixel configured to display first color image data, the first subpixel including a first liquid crystal shutter configured to be activated to an open position and a closed position, and a first color filter configured to allow passage of a first color of light and prevent passage of a second color of light;

a second subpixel configured to display second color image data, the second subpixel including a second liquid crystal shutter configured to be activated to an open position and a closed position, and a second color filter configured to allow passage of the second color of light and prevent passage of the first color of light; and

a third subpixel configured to display third color image data, the third subpixel including a third liquid crystal shutter configured to be activated to an open position and a closed position, wherein the third subpixel does not include a color filter.

18. The screen of claim 17, further comprising:

a shutter controller configured to selectively activate the first and second liquid crystal shutters to the open position to generate a first image component including a combination of the first color image data and the second color image data, and to selectively activate the third liquid crystal shutter to the open position to generate a second image component including the third color image data,

wherein the pixel array is configured to sequentially display the first and second image components to provide the image.

19. The screen of claim 18, wherein the shutter controller is configured to activate the third liquid crystal shutter to the closed position to generate the first image component.

20. The screen of claim 18, wherein the shutter controller is further configured to activate the first and second liquid crystal shutters to the closed position to generate the second image component.

21. The screen of claim 20, wherein the first and second color filters are configured to allow passage of the third color of light.

22. The screen of claim 18, wherein the first and second color filters are further configured to prevent passage of the third color of light, and wherein the shutter controller is further configured to activate the first and/or second liquid crystal shutters to the open position to generate the second image component.

23. The screen of claim 17, wherein a wavelength of the third color is greater than a wavelength of the second color but less than a wavelength of the first color.

24. The screen of claim 23, wherein the first color comprises red, wherein the second color comprises blue, and wherein the third color comprises green.

25. The screen of claim 17, wherein the first color comprises blue, wherein the second color comprises green, and wherein the third color comprises red.

26. The screen of claim 17, wherein the first color comprises green, wherein the second color comprises red, and wherein the third color comprises blue.

27. A method for operating a liquid crystal display (LCD) device including a backlight and a pixel array, the method comprising:

activating the backlight to simultaneously emit first and second colors of light to generate a first image component including a combination of first color image data and second color image data;

activating the backlight to separately emit a third color of light at a different time than the first and second colors of light to generate a second image component including third color image data; and

activating the pixel array to display the first and second image components to provide a single image frame,

wherein the pixel array includes a plurality of pixels respectively comprising first, second, and third subpixels configured to display first, second, and third color image data, respectively,

wherein the first, second, and third subpixels include first, second, and third liquid crystal shutters, respectively, wherein each of the liquid crystal shutters is configured to be activated to an open position and a closed position, and

wherein the first and second subpixels include first and second color filters, respectively, wherein the first color filter is configured to allow passage of the first color of light and prevent passage of the second color of light, wherein the second color filter is configured to allow passage of the second color of light and prevent passage of the first color of light, and wherein the third subpixel is configured to allow passage of the first and/or second colors of light in the open position.

28. The method of claim 27, wherein the third subpixel does not include a color filter, and wherein activating the pixel array further comprises:

selectively activating the first and second liquid crystal shutters to an open position and activating the third liquid crystal shutter to a closed position to generate the first image component; and

selectively activating the third liquid crystal shutter to an open position to generate the second image component.

29. The method of claim 28, wherein activating the third liquid crystal shutter to the closed position comprises:

activating the third liquid crystal shutter to the closed position concurrently with activating the backlight to simultaneously emit the first and second colors of light to prevent passage of the first and second colors of light.

30. The method of claim 29, wherein selectively activating the first and second liquid crystal shutters comprises:

selectively activating the first and second liquid crystal shutters to the open position concurrently with activating the backlight to simultaneously emit the first and second colors of light to combine the first color image data and the second color image data.

31. The method of claim 28, wherein selectively activating the third liquid crystal shutter to the open position comprises:

selectively activating the third liquid crystal shutter to the open position concurrently with activating the backlight to emit the third color of light to allow passage of the third color of light.

32. The method of claim 31, further comprising:

activating the first and second liquid crystal shutters to the closed position concurrently with activating the backlight to emit the third color of light.

33. The method of claim 31, wherein the first and second subpixels respectively include first and second color filters configured to prevent passage of the third color of light, and further comprising:

activating the first and/or second liquid crystal shutters to the open position concurrently with activating the backlight to emit the third color of light.

34. The method of claim 28, wherein the first and second subpixels respectively include first and second color filters configured to prevent passage of the third color of light, and wherein activating the backlight to simultaneously emit first and second colors of light further comprises:

activating the backlight to simultaneously emit the first, second, and third colors of light to generate the first image component.

35. The method of claim 28, further comprising:

alternating between activating the backlight to emit the first and second colors of light simultaneously and activating the backlight to emit the third color of light based on a shutter rate of the first, second, and/or third liquid crystal shutters.

36. The method of claim 28, wherein the backlight comprises first, second, and third solid state lighting elements respectively configured to emit light of the first, second, and third colors, and wherein activating the backlight to simultaneously emit first and second colors of light and activating the backlight to emit the third color of light comprises:

activating the first and second solid state lighting elements substantially simultaneously to generate the first image component; and

activating the third solid state lighting element at a different time than the first and second solid state lighting elements to generate the second image component.

37. The method of claim 27, wherein a wavelength of the third color of light is greater than a wavelength of the second color of light but less than a wavelength of the first color of light.

38. The method of claim 37, wherein the first color of light comprises red light, wherein the second color of light comprises blue light, and wherein the third color of light comprises green light.

39. The method of claim 27, wherein the first color of light comprises blue light, wherein the second color of light comprises green light, and wherein the third color of light comprises red light.

40. The method of claim 27, wherein the first color of light comprises green light, wherein the second color of light comprises red light, and wherein the third color of light comprises blue light.