Liquid crystal display device

• US 20050259064A1
• Filed: 12/08/2003
• Published: 11/24/2005
• Est. Priority Date: 12/06/2002
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Fujine, Toshiyuki, Yoshii, Takashi, Sugino, Michiyuki
• Granted Patent: US 8,451,209 B2
• Time in Patent Office: Days
• US Class Current: 345/102
• 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 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/062 Adjustment of illumination source parameters
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 2320/08 Arrangements within a display terminal for setting, manually or automatically, display parameters of the display terminal
• CPC Class Codes: G09G 2320/10 Special adaptations of display systems for operation with variable images
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• 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 device in which a frame of the image signal to be displayed is written into a liquid crystal display panel while a backlight is activated intermittently within one frame period so as to prevent blur injury arising when displaying motion pictures includes: sections and for variably controlling the illumination duration of the backlight based on the detected type of the image content to be displayed. This configuration makes it possible to appropriately control the image quality degradation caused by blur injury, stroboscopic effect and flickering, hence realize total image quality improvement.

Claims

1. A liquid crystal display device wherein the image signal to be displayed is written into a liquid crystal display panel while a backlight is activated intermittently within one frame period, comprising:

a section for detecting the type of the image content to be displayed; and

a section for variably controlling the illumination duration of the backlight based on the detected type of the image content.

2. The liquid crystal display device according to claim 1, wherein the backlight emits a flash of light over the full screen every one frame period in synchronization with the vertical synchronizing signal supplied to the liquid crystal display panel.

3. The liquid crystal display device according to claim 1, wherein the backlight is operated so that multiple luminous sections are activated, one to the next, scan-wise in synchronization with the vertical and horizontal synchronizing signals supplied to the liquid crystal display panel.

4. The liquid crystal display device according to claim 1, wherein the luminous intensity of the backlight is varied in accordance with the illumination duration of the backlight.

5. The liquid crystal display device according to claim 1, wherein the gray scale levels of the input image signal are varied in accordance with the illumination duration of the backlight.

6. The liquid crystal display device according to claim 1, wherein the gray scale voltages applied to the liquid crystal display panel in response to the input image signal are varied in accordance with the illumination duration of the backlight.

7. The liquid crystal display device according to claim 1, wherein the frame frequency of the input image signal is varied based on the type of the image content.

8. The liquid crystal display device according to claim 1, wherein the type of the image content to be displayed is detected based on the contents information included in the broadcast data.

9. The liquid crystal display device according to claim 1, wherein the type of the image content to be displayed is detected based on the contents information obtained from external media.

10. The liquid crystal display device according to claim 1, wherein the type of the image content to be displayed is detected based on the video source select command information input by the user.

11. A liquid crystal display device wherein the image signal to be displayed and the black display signal are written into a liquid crystal display panel within one frame period, comprising:

a section for detecting the type of the image content to be displayed; and

a section for variably controlling the duration in which the black display signal is supplied to the liquid crystal display panel based on the detected type of the image content.

12. The liquid crystal display device according to claim 11, wherein the luminous intensity of the backlight that illuminates the liquid crystal display panel is varied in accordance with the application duration of the black display signal.

13. The liquid crystal display device according to claim 11, wherein the gray scale levels of the input image signal are varied in accordance with the application duration of the black display signal.

14. The liquid crystal display device according to claim 11, wherein the gray scale voltages applied to the liquid crystal display panel in response to the input image signal are varied in accordance with the application duration of the black display signal.

15. The liquid crystal display device according to claim 11, wherein the type of the image content to be displayed is detected based on the contents information included in the broadcast data.

16. The liquid crystal display device according to claim 11, wherein the type of the image content to be displayed is detected based on the contents information obtained from external media.

17. The liquid crystal display device according to claim 11, wherein the type of the image content to be displayed is detected based on the video source select command information input by the user.

18. A liquid crystal display device wherein display duration of the image signal and non-display duration are provided in one frame period, comprising:

a section for detecting the type of the image content to be displayed; and

a section for variably controlling the ratio of the display duration of the image signal in the one frame period, based on the detected type of the image content.

19. The liquid crystal display device according to claim 18, wherein the gray scale levels of the input image signal are varied in accordance with the ratio of the display duration of the image signal in the one frame period.

20. The liquid crystal display device according to claim 18, wherein the gray scale voltages applied to the liquid crystal display panel in response to the input image signal are varied in accordance with the ratio of the display duration of the image signal in the one frame period.

21. The liquid crystal display device according to claim 18, wherein the type of the image content to be displayed is detected based on the contents information included in the broadcast data.

22. The liquid crystal display device according to claim 18, wherein the type of the image content to be displayed is detected based on the contents information obtained from external media.

23. The liquid crystal display device according to claim 18, wherein the type of the image content to be displayed is detected based on the video source select command information input by the user.

24. A liquid crystal display device wherein the image signal to be displayed is written into a liquid crystal display panel while a backlight is activated intermittently within one frame period, comprising:

a section for detecting a user'"'"'s instructional input; and

a section for variably controlling the illumination duration of the backlight based on the detected user'"'"'s instructional input.

25. The liquid crystal display device according to claim 24, wherein the backlight emits a flash of light over the full screen every one frame period in synchronization with the vertical synchronizing signal supplied to the liquid crystal display panel.

26. The liquid crystal display device according to claim 24, wherein the backlight is operated so that multiple luminous sections are activated, one to the next, scan-wise in synchronization with the vertical and horizontal synchronizing signals supplied to the liquid crystal display panel.

27. The liquid crystal display device according to claim 24, wherein the luminous intensity of the backlight is varied in accordance with the illumination duration of the backlight.

28. The liquid crystal display device according to claim 24, wherein the gray scale levels of the input image signal are varied in accordance with the illumination duration of the backlight.

29. The liquid crystal display device according to claim 24, wherein the gray scale voltages applied to the liquid crystal display panel in response to the input image signal are varied in accordance with the illumination duration of the backlight.

30. The liquid crystal display device according to claim 24, wherein the frame frequency of the input image signal is varied based on the user'"'"'s instruction.

31. The liquid crystal display device according to claim 24, wherein the illumination duration of the backlight is varied based on the video source select command information input by the user.

32. The liquid crystal display device according to claim 24, wherein the illumination duration of the backlight is varied based on the video adjustment command information input by the user.

33. A liquid crystal display device wherein the image signal to be displayed and the black display signal are written into a liquid crystal display panel within one frame period, comprising:

a section for detecting a user'"'"'s instructional input; and

a section for variably controlling the duration in which the black display signal is supplied to the liquid crystal display panel based on the user'"'"'s instructional input.

34. The liquid crystal display device according to claim 33, wherein the luminous intensity of the backlight that illuminates the liquid crystal display panel is varied in accordance with the application duration of the black display signal.

35. The liquid crystal display device according to claim 33, wherein the gray scale levels of the input image signal are varied in accordance with the application duration of the black display signal.

36. The liquid crystal display device according to claim 33, wherein the gray scale voltages applied to the liquid crystal display panel in response to the input image signal are varied in accordance with the application duration of the black display signal.

37. The liquid crystal display device according to claim 33, wherein the application duration of the black display signal is varied based on the video source select command information input by the user.

38. The liquid crystal display device according to claim 33, wherein the application duration of the black display signal is varied based on the video adjustment command information input by the user.

39. A liquid crystal display device wherein display duration of the image signal and non-display duration are provided in one frame period, comprising:

a section for detecting a user'"'"'s instructional input; and

a section for variably controlling the ratio of the display duration of the image signal in the one frame period, based on the detected user'"'"'s instruction.

40. The liquid crystal display device according to claim 39, wherein the gray scale levels of the input image signal are varied in accordance with the ratio of the display duration of the image signal in the one frame period.

41. The liquid crystal display device according to claim 39, wherein the gray scale voltages applied to the liquid crystal display panel in response to the input image signal are varied in accordance with the ratio of the display duration of the image signal in the one frame period.

42. The liquid crystal display device according to claim 39, wherein the ratio of the display duration of the image signal in the one frame period is varied based on the video source select command information input by the user.

43. The liquid crystal display device according to claim 39, wherein the ratio of the display duration of the image signal in the one frame period is varied based on the video adjustment command information input by the user.