Apparatus and method to improve quality of moving image displayed on liquid crystal display device

• US 8,279,165 B2
• Filed: 05/18/2010
• Issued: 10/02/2012
• Est. Priority Date: 10/13/1999
• Status: Expired due to Fees

• Current Assignee: Eliving, LLC
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Yoshida, Hidefumi, Tanuma, Seiji, Mayama, Takatoshi, Inoue, Yuichi, Suzuki, Toshiaki, Hanaoka, Kazutaka, Gotoh, Takeshi, Kobayashi, Tetsuya, Ohashi, Makoto, Yamaguchi, Hisashi, Tanaka, Katsunori, Katagawa, Koichi
• Primary Examiner(s): Dinh, Duc
• Application Number:
  US12/782,440
• Publication Number:
  US 20100225633A1
• Time in Patent Office: 868 Days
• Field of Search: 345/102, 345/207, 345/87, 345/690, 345/204, 345/98, 345/99, 345/100, 349 61- 65, 349 69- 70
• 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 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2310/062 Waveforms for resetting a plurality of scan lines at a time
• CPC Class Codes: G09G 2310/063 Waveforms for resetting the whole screen at once
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0238 Improving the black level
• 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 2330/021 Power management, e.g. power saving
• 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 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 3/3666 with the matrix divided into sections

Abstract

A liquid crystal display device includes a panel having pixel electrodes arranged at intersections of a plurality of signal lines via switching elements for transmitting display data and a plurality of scanning lines for transmitting control signals, and a control circuit for controlling the panel. The liquid crystal panel is divided into first pixel regions and second pixel regions adjacent to the first pixel regions. The control circuit carries out impulse driving in which the control signals transmitted to each of the scanning lines are activated two times in one frame period for displaying an image. The control circuit writes the display data in either one of the pixel regions and writes reset data in the other pixel regions when the control signals are activated once of the two times. By writing the reset data in the pixel regions, the display data written in an immediately preceding frame are reset. In consecutive frames, the display data written in the pixel regions are always reset in one frame period. Therefore, blurring in a moving image can be alleviated. Since writing the display data and the reset data is carried out separately in the first pixel regions and in the second pixel regions, flicker is prevented from occurring in a display screen.

Claims

1. A liquid crystal display device comprising:

a liquid crystal panel in which a plurality of signal lines for transmitting display data and a plurality of control lines for transmitting control signals laid out vertically and horizontally, and pixel electrodes are arranged at intersections of the signal lines and the control lines via switching elements; and

an illumination device, wherein said illumination device comprises;

a light guide plate facing said liquid crystal panel; and

a backlight supplying light to said light guide plate,

wherein said light guide plate comprises a plurality of luminescent parts, for emitting light guided therein toward said liquid crystal panel, each of the luminescent parts illuminating a corresponding pixel region among all pixels,

wherein emitting the light toward the liquid crystal panel through each of the luminescent parts is turned on or off according to a timing within a frame period, and wherein only a section of the luminescent parts, which section is for illuminating a subjected pixel region that is subject to illumination among all pixels, is turned on at each timing within a frame period, the subjected pixel region being a pixel region where a predetermined waiting time has passed since scan by the control lines and a predetermined illumination time has not passed since pass of the waiting time, and

wherein the waiting time is 1 frame period×

(n−

2)/n, which is a worst response time of a liquid crystal, with n being the number of the pixel regions.

2. A liquid crystal display device according to claim 1, wherein

a plurality of film-like scattering parts are arranged on said light guide plate, along said scanning lines, for totally or irregularly reflecting light penetrating through said light guide plate, and

said luminescent parts are formed by irregular reflection of said light by said scattering parts.

3. A liquid crystal display device according to claim 2, wherein said scattering parts are arranged in parallel on a surface of said light guide plate.

4. A liquid crystal display device according to claim 3, wherein each of said scattering parts is arranged on the surface of said light guide plate, on the side of said liquid crystal panel.

5. A liquid crystal display device according to claim 3, wherein each of said scattering parts is arranged on the surface of said light guide plate, on the opposite side of said liquid crystal panel.

6. A liquid crystal display device according to claim 3, comprising a plurality of said light guide plates facing each other, wherein each of said scattering parts is arranged between said light guide plates.

7. A liquid crystal display device according to claim 6, wherein said scattering parts are further arranged on outer surfaces of said light guide plates.

8. A liquid crystal display device according to claim 2, wherein said scattering parts are arranged within said light guide plate, so as to cut across a direction light is guided.

9. A liquid crystal display device according to claim 8, wherein said scattering parts are arranged orthogonal to said direction light is guided.

10. A liquid crystal display device according to claim 8, wherein said scattering parts are arranged diagonal to said direction light is guided.

11. A liquid crystal display device according to claim 8, wherein said scattering parts extend from a surface of said light guide plate that faces said liquid crystal panel to an opposite surface of said light guide plate.

12. A liquid crystal display device according to claim 1, wherein

said backlight includes a light source supplying the light to said light guide plate, and

a plurality of the luminescent parts are disposed along an incident direction from said light source to the light guide plate.

13. A liquid crystal display device according to claim 12, wherein

a plurality of film-like parts are arranged on said light guide plate, along an incident direction from said light source to the light guide plate, for totally or irregularly reflecting or refracting light penetrating through said light guide plate.

14. A liquid crystal display device according to claim 12, wherein said film-like parts are arranged so as to be controlled integrally in a direction parallel with an incident surface of said light guide plate from said light source.

15. A liquid crystal display device according to claim 12, wherein said film-like parts are arranged so as to be controlled integrally at every area extending in a longitudinal direction of an incident surface of said light guide plate from said light source.

16. A liquid crystal display device according to claim 12, wherein said film-like parts are arranged so as to be controlled separately at every distance from an incident surface of said light guide plate from said light source.

17. A liquid crystal display device according to claim 12, wherein said film-like parts are arranged so as to be controlled integrally at every area extending in a horizontal direction of said liquid crystal panel, and

said luminescent parts are scanned in a vertical direction of said liquid crystal panel.

18. A liquid crystal display device according to claim 2, wherein said scattering parts are formed with a liquid crystal film of high-molecular type.

19. A liquid crystal display device according to claim 18, wherein a resin layer covering low molecular liquid crystal in said liquid crystal film is formed with high-molecular liquid crystal.

20. A liquid crystal display device according to claim 19, wherein said low molecular liquid crystal and said high-molecular liquid crystal are aligned orthogonal to a surface of said liquid crystal film in a state where voltage is not supplied thereto.

21. A liquid crystal display device according to claim 20, wherein said low molecular liquid crystal has negative dielectric anisotropy.

22. A liquid crystal display device according to claim 19, wherein said low molecular liquid crystal and said high-molecular liquid crystal are aligned orthogonal to a direction light is guided in a state where a voltage is not supplied thereto.

23. A liquid crystal display device according to claim 1, wherein a plurality of film-like optical parts are arranged on said light guide plate, for totally or regularly or irregularly reflecting light penetrating through said light guide plate, thereby scattering or changing a penetrating direction of the light.

24. A liquid crystal display device according to claim 23,

wherein said optical parts are formed with a liquid crystal film which can switch turning on or off of emitting the light toward the liquid crystal panel by application of a voltage to the liquid crystal film.

25. A liquid crystal display device according to claim 24,

wherein the liquid crystal film is formed without a border corresponding to the luminescent parts on an entirety of an inner or outer surface of the light guide plate and wherein the voltage of a value corresponding to each of the luminescent parts is applied to each portion of the liquid crystal film.

26. A liquid crystal display device according to claim 23, wherein turning on or off of emitting the light toward the liquid crystal panel is controlled by turning on or off of totally or regularly or irregularly reflecting the light at said optical parts.

27. A liquid crystal display device according to claim 23, wherein the optical parts collect the light into the subjected pixel region.

28. A liquid crystal device according to claim 1, wherein the light guide plate has a plurality of the luminescent parts with respect to one backlight.

29. A liquid crystal display device according to claim 1, wherein turning on or off of emitting the light toward the liquid crystal panel is controlled by turning on or off of said backlight.

30. A liquid crystal display device according to claim 1, wherein the illumination time is equal to a time taken for scan of all pixels in the subjected pixel region.

31. A liquid crystal display device according to claim 1, wherein the illumination device collects the light into the subjected pixel region.

32. A liquid crystal display device according to claim 1, wherein the backlight is arranged at one end of said light guide plate.

33. A liquid crystal display device comprising:

a liquid crystal panel in which a plurality of signal lines for transmitting display data and a plurality of scanning lines for transmitting control signals are laid out vertically and horizontally, and pixel electrodes are arranged at intersections of the signal lines and the scanning line via switching elements, the liquid crystal panel comprising a plurality of control blocks divided into n portions (n≧

5) along said scanning lines; and

a plurality of backlights facing each of said control blocks, wherein

said liquid crystal panel carries out impulse driving in which each of said scanning lines is scanned twice in one frame period and said display data and reset data are written in said pixel electrodes,

said backlights corresponding to each of said control blocks are turned on for a predetermined period immediately before scanning said scanning lines in the control blocks, and

a response time of each pixel in said liquid crystal panel is smaller than;

1 frame period×

[[(n−

1)/2n]−

(1/n)] (n;

odd number), or

1 frame period×

[[(n−

2)/2n]−

(1/n)] (n;

even number),

which are worst response times of a liquid crystal.