Liquid crystal display apparatus capable of maintaining high color purity

• US 20060007108A1
• Filed: 06/21/2005
• Published: 01/12/2006
• Est. Priority Date: 06/21/2004
• Status: Active Grant

• Current Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Inventors: Konno, Akitoyo, Tomioka, Yasushi, Kondo, Katsumi, Utsumi, Yuka
• Granted Patent: US 7,893,903 B2
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• 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 3/3611 Control of matrices with row and column drivers

Abstract

A liquid crystal display apparatus having first white color light sources and blue and/or red second coloring light sources disposed on a back side of a liquid crystal panel, and an image quality processing calculation circuit for detecting a brightness of input image signals, in accordance with a detection result, controlling intensities of the first white color light sources and/or second coloring light sources and correcting pixel signals to be supplied to the liquid crystal panel.

Claims

1. A liquid crystal display apparatus comprising:

first white color light sources and second coloring light sources respectively for irradiating light upon a liquid crystal panel for displaying an image;

a detection circuit for detecting a brightness of an input signal; and

a image quality processing calculation circuit for outputting a light source control signal an image control signal in accordance with a detection result be said detection circuit, said light source control signal independently controlling an intensity of said first white color light sources and an intensity of said second coloring light sources, and said image control signal controlling an image to be displayed on said liquid crystal.

2. The liquid crystal display apparatus according to claim 1, wherein:

said second coloring light sources are red light sources; and

said image quality processing calculation circuit outputs said light source control signal for reducing an intensity of said first white color light sources and controlling an intensity of said red light sources and said image control signal for controlling an image to be displayed on said liquid crystal panel, if it is detected that an average luminance of input image signals is lower than a predetermined luminance and a maximum luminance is lower than a predetermined luminance.

3. The liquid crystal display apparatus according to claim 1, wherein:

said second coloring light sources are blue light sources; and

said image quality processing calculation circuit outputs said light source control signal for controlling an intensity of said blue light sources and said image control signal for controlling an image to be displayed on said liquid crystal panel, if it is detected that an average luminance of input image signals is higher than a predetermined luminance.

4. The liquid crystal display apparatus according to claim 1, wherein:

said second coloring light sources are red and blue light sources; and

said image quality processing calculation circuit outputs said light source control signal for reducing an intensity of said first white color light sources and controlling an intensity of said red light sources and said image control signal for controlling an image to be displayed on said liquid crystal panel, if it is detected that an average luminance of input image signals is equal to or lower than a predetermined luminance and a maximum luminance is equal to or lower than a predetermined luminance, and outputs said light source control signal for controlling an intensity of said blue light sources and said image control signal for controlling an image to be displayed on said liquid crystal panel, if it is detected that an average luminance of input image signals is higher than a predetermined luminance.

5. The liquid crystal display apparatus according to claim 1, wherein:

said first white color light sources and second coloring light sources are cold cathode fluorescent lamps made of narrow peak band emitted phosphor.

6. The liquid crystal display apparatus according to claim 1, wherein:

said first white color light sources are cold cathode fluorescent lamps made of narrow peak band emitted phosphor;

said second coloring light sources are organic electro luminance elements.

7. The liquid crystal display apparatus according to claim 1, wherein:

said first white color light sources are cold cathode fluorescent lamps made of narrow peak band emitted phosphor;

said second coloring light sources are light emitting diode elements.

8. The liquid crystal display apparatus according to claim 1, wherein:

said first white color light sources and second coloring light sources are light emitting diode elements.

9. The liquid crystal display apparatus according to claim 1, wherein:

a diffusion plate is disposed on a back side of said liquid crystal panel, said diffusion plate mixing light from said first white color light sources and light from second coloring light sources.

10. The liquid crystal display apparatus according to claim 1, wherein:

said second coloring light sources are disposed at lease one side of a light pipe disposed on a back side of said liquid crystal panel,

wherein said light pope makes light from said first white color sources transmit and light form said second coloring light sources uniformalize to irradiate light to said liquid crystal panel.

11. The liquid crystal display apparatus according to claim 1, wherein:

said second coloring light sources are a plurality type of different elements,

and at lease one type of said second coloring light sources are disposed at lease one side of a light pipe disposed on a back side of said liquid crystal panel,

wherein said light pope makes light from said first white color sources transmit and light form said second coloring light sources uniformalize to irradiate light to said liquid crystal panel.

12. The liquid crystal display apparatus according to claim 1, wherein said liquid crystal panel is of an in-plane switching mode and a normally close type.

13. The liquid crystal display apparatus according to claim 1, wherein said liquid crystal panel is of an vertical alignment mode and a normally close type.

14. The liquid crystal display apparatus according to claim 1, wherein a pixel unit of said liquid crystal panel is constituted of red, green, blue subsidiary pixels with red, green and blue filters and a subsidiary pixel without color filter for displaying only transmission light intensity.

15. A liquid crystal display apparatus comprising:

first white color light sources and second coloring light sources respectively for irradiating light upon a liquid crystal panel for displaying an image;

a detection circuit for detecting a brightness of an input image signal; and

an image quality processing calculation circuit for outputting a light source control signal and an image control signal in accordance with a detection result by said detection circuit, said light source control signal controlling an intensity of said second coloring light sources, and said image control signal controlling an image to be displayed on said liquid crystal panel.

16. The liquid crystal display apparatus according to claim 15, wherein:

said second coloring light sources are red light sources; and

said image quality processing calculation circuit outputs said light source control signal for controlling an intensity of said red light sources and said image control signal for controlling an image to be displayed on said liquid crystal panel, if it is detected that an average luminance of input image signals is lower than a predetermined luminance and a maximum luminance is lower than a predetermined luminance.

17. The liquid crystal display apparatus according to claim 15, wherein:

said second coloring light sources are blue light sources; and

said image quality processing calculation circuit outputs said light source control signal for controlling an intensity of said blue light sources and said image control signal for controlling an image to be displayed on said liquid crystal panel, if it is detected that an average luminance of input image signals is higher than a predetermined luminance.

18. The liquid crystal display apparatus according to claim 15, wherein:

said second coloring light sources are red and blue light sources; and

said image quality processing calculation circuit outputs said light source control signal for controlling an intensity of said red light sources and said image control signal for controlling an image to be displayed on said liquid crystal panel, if it is detected that an average luminance of input image signals is equal to or lower than a predetermined luminance and a maximum luminance is equal to or lower than a predetermined luminance, and outputs said light source control signal for controlling an intensity of said blue light sources and said image control signal for controlling an image to be displayed on said liquid crystal panel, if it is detected that an average luminance of input image signals is higher than a predetermined luminance.

19. The liquid crystal display apparatus according to claim 15, wherein:

said first white color light sources and second coloring light sources are cold cathode fluorescent lamps made of narrow peak band emitted phosphor.

20. The liquid crystal display apparatus according to claim 15, wherein:

said first white color light sources are cold cathode fluorescent lamps made of narrow peak band emitted phosphor;

said second coloring light sources are organic electro luminance elements.

21. The liquid crystal display apparatus according to claim 15, wherein:

said first white color light sources are cold cathode fluorescent lamps made of narrow peak band emitted phosphor;

said second coloring light sources are light emitting diode elements.

22. The liquid crystal display apparatus according to claim 15, wherein:

said first white color light sources and second coloring light sources are light emitting diode elements.

23. The liquid crystal display apparatus according to claim 15, wherein:

a diffusion plate is disposed on a back side of said liquid crystal panel, said diffusion plate mixing light from said first white color light sources and light from second coloring light sources.

24. The liquid crystal display apparatus according to claim 15, wherein:

said second coloring light sources are disposed at lease one side of a light pipe disposed on a back side of said liquid crystal panel,

wherein said light pope makes light from said first white color sources transmit and light form said second coloring light sources uniformalize to irradiate light to said liquid crystal panel.

35. The liquid crystal display apparatus according to claim 21, wherein said image processing calculation circuit outputs said light source control signal for controlling independently intensities of said first light sources and said second red light sources and said image control signal for controlling an image to be displayed on said liquid crystal panel, in accordance with a detection result from a detection circuit for detecting a neighboring brightness of said liquid crystal panel.

36. The liquid crystal display apparatus according to claim 22, wherein said image processing calculation circuit outputs said light source control signal for controlling independently intensities of said first light sources and said second red light sources and said image control signal for controlling an image to be displayed on said liquid crystal panel, in accordance with a detection result from a detection circuit for detecting a neighboring brightness of said liquid crystal panel.

37. The liquid crystal display apparatus according to claim 21, wherein said first light sources are fluorescent lamps made of mainly blue and red narrow peak band emitted phosphors, and said second read light sources are red light emitting diodes.

38. The liquid crystal display apparatus according to claim 22, wherein said first light sources are fluorescent lamps made of mainly blue and red narrow peak band emitted phosphors, and said second read light sources are red light emitting diodes.

39. The liquid crystal display apparatus according to claim 24, wherein a diffusion unit for mixing light from said first light sources and light from said second red light sources is disposed on a back side of said liquid crystal panel.

40. The liquid crystal display apparatus according to claim 24, wherein said second red light sources are disposed at lease along one side of a light guiding plate disposed on a back side of said liquid crystal panel, and said light guiding plate transmits light from said first light sources, makes uniform light from said second red light sources, and illuminates the back side of said liquid crystal panel.

25. A liquid crystal display apparatus comprising:

first white color sources and second light sources respectively for irradiating light upon a liquid crystal panel for displaying an image;

a detection circuit for detecting a brightness of an input image signal; and

a image quality processing calculation circuit for outputting a light source control signal and an image control signal in accordance with a detection result by said detection circuit and a detection result by a detection circuit for detecting a peripheral brightness of said liquid crystal panel, said light source control signal independently controlling an intensity of said first white color light sources and an intensity of said second coloring light sources, and said image control signal controlling an image to be displayed on said liquid crystal panel,

for reducing luminance of said light sources, if it is detected that a peripheral brightness is lower than a predetermined illuminance.

26. The liquid crystal display apparatus according to claim 25, wherein:

said second coloring light sources are red light sources; and

said image quality processing calculation circuit outputs said light source control signal for controlling an intensity of said red light sources and said image control signal for controlling an image to be displayed on said liquid crystal panel, if it is detected that an average luminance of input image signals is lower than a predetermined luminance and a maximum luminance is lower than a predetermined luminance.

27. The liquid crystal display apparatus according to claim 25, wherein:

said second coloring light sources are blue light sources; and

said image quality processing calculation circuit outputs said light source control signal for controlling an intensity of said blue light sources and said image control signal for controlling an image to be displayed on said liquid crystal panel, if it is detected that an average luminance of input image signals is higher than a predetermined luminance.

28. The liquid crystal display apparatus according to claim 25, wherein:

said second coloring light sources are red and blue light sources; and

said image quality processing calculation circuit outputs said light source control signal for controlling an intensity of said red light sources and said image control signal for controlling an image to be displayed on said liquid crystal panel, if it is detected that an average luminance of input image signals is equal to or lower than a predetermined luminance and a maximum luminance is equal to or lower than a predetermined luminance, and outputs said light source control signal for controlling an intensity of said blue light sources and said image control signal for controlling an image to be displayed on said liquid crystal panel, if it is detected that an average luminance of input image signals is higher than a predetermined luminance.

29. The liquid crystal display apparatus according to claim 25, wherein:

said first white color light sources and second coloring light sources are cold cathode fluorescent lamps made of narrow peak band emitted phosphor.

30. The liquid crystal display apparatus according to claim 25, wherein:

said first white color light sources are cold cathode fluorescent lamps made of narrow peak band emitted phosphor;

said second coloring light sources are organic electro luminance elements.

31. The liquid crystal display apparatus according to claim 25, wherein:

said first white color light sources are cold cathode fluorescent lamps made of narrow peak band emitted phosphor;

said second coloring light sources are light emitting diode elements.

32. The liquid crystal display apparatus according to claim 25, wherein:

said first white color light sources and second coloring light sources are light emitting diode elements.

33. The liquid crystal display apparatus according to claim 25, wherein:

a diffusion plate is disposed on a back side of said liquid crystal panel, said diffusion plate mixing light from said first white color light sources and light from second coloring light sources.

34. The liquid crystal display apparatus according to claim 25, wherein:

said second coloring light sources are disposed at lease one side of a light pipe disposed on a back side of said liquid crystal panel,

wherein said light pope makes light from said first white color sources transmit and light form said second coloring light sources uniformalize to irradiate light to said liquid crystal panel.

41. A liquid crystal display apparatus comprising:

first light sources and second red light sources for irradiating light to a liquid crystal panel for displaying an image; and

an image processing calculation circuit for outputting a light source control signal for controlling independently intensities of said first light sources and said second red light sources and an image control signal for controlling an image to be displayed on said liquid crystal panel, in accordance with a detection result from a detection circuit for detecting a brightness of an input image signal,

wherein if it is detected that an average luminance of input image signals is lower than a predetermined luminance and a maximum luminance is lower than a predetermined luminance, said image quality processing calculation circuit lowers the intensity of said first light sources and outputs a light control signal for controlling the intensity of said second red light sources independently from said first light sources and said image control signal for controlling an image to be displayed on said liquid crystal panel.

42. A liquid crystal display apparatus comprising:

first light sources and second red light sources for irradiating light to a liquid crystal panel for displaying an image; and

an image processing calculation circuit for outputting a light source control signal for controlling independently intensities of said first light sources and said second red light sources and an image control signal for controlling an image to be displayed on said liquid crystal panel, in accordance with a detection result from a detection circuit for detecting a brightness of an input image signal,

wherein if it is detected that an average luminance of input image signals is higher than the predetermined luminance, said image quality processing calculation circuit lowers the intensity of said first light sources and outputs a light control signal for controlling the intensity of said second red light sources independently from said first light sources and said image control signal for controlling an image to be displayed on said liquid crystal panel.