Display method for liquid crystal display device

• US 20020003522A1
• Filed: 07/06/2001
• Published: 01/10/2002
• Est. Priority Date: 07/07/2000
• Status: Active Grant

• Current Assignee: Hisense Visual Technology Co., Ltd. (Qingdao Huatong State-Owned Capital Operation (Group) Co., Ltd.)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Yamaguchi, Hajime, Kobayashi, Hitoshi, Itoh, Goh, Baba, Masahiro, Okumura, Haruhiko, Hasegawa, Rei
• Granted Patent: US 7,106,350 B2
• Time in Patent Office: Days
• US Class Current: 345/89
• 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 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0204 Compensation of DC component across the pixels in flat panels
• CPC Class Codes: G09G 2320/0209 Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
• 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 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• 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 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• 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 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/2025 the sub-frames having all the same time duration
• 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 3/3614 : Control of polarity reversal in general
• CPC Class Codes: G09G 3/3651 : using multistable liquid crystals, e.g. ferroelectric liquid crystals
• CPC Class Codes: G09G 3/3659 : the addressing of the pixel involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependant on signal of two data electrodes

Abstract

A liquid crystal display method to display an image according to an image signal, comprises changing a ratio of a display period and a non-display period of the image according to the image signal.

Claims

1. A liquid crystal display method to display an image according to an image signal, comprising

changing a ratio of a display period and a nondisplay period of said image according to said image signal.

2. The liquid crystal display method according to claim 1, wherein said step of changing the ratio of the lightening period and the non-lightening period of said light part includes changing a lightening or no-lightening of a backlight provided on a back side of said liquid crystal panel.

3. The liquid crystal display method according to claim 1, wherein said step of changing the ratio of the lightening period and the non-lightening period of said light part includes changing a transmittance or no-transmittance of a shutter element provided on said backlight or on a front side of said liquid crystal panel.

4. The liquid crystal display method according to claim 1, wherein said step of changing the ratio of the display period and the non-display period of said image includes changing a ratio of a lightening period and a non-lightening period of a light part, which lightens said liquid crystal panel from back side.

5. The liquid crystal display method according to claim 4, wherein said step of changing the ratio of the lightening period and the non-lightening period of said light part includes changing a lightening or no-lightening of a backlight provided on a back side of said liquid crystal panel.

6. The liquid crystal display method according to claim 4, wherein said step of changing the ratio of the lightening period and the non-lightening period of said light part includes changing a transmittance or no-transmittance of a shutter element provided on said backlight or on a front side of said liquid crystal panel.

7. The liquid crystal display method according to claim 1, wherein said step of changing the ratio of the display period and the non-display period of said image includes changing a ratio of a period when the image display signal, which corresponds to said image signal is supplied and a period when the black display signal is supplied to said liquid crystal panel.

8. The liquid crystal display method according to claim 1, further comprising:

detecting a maximum brightness level of said image signal;

changing a ratio of a display period and a nondisplay period of said image according to said detected maximum brightness level; and

changing a gray-scale of said image signal based on said ratio of the display period and the non-display period of said image according to said image signal.

9. The liquid crystal display method according to claim 8, wherein said step of changing the ratio of the lightening period and the non-lightening period of said light part includes changing a lightening or no-lightening of a backlight provided on a back side of said liquid crystal panel.

10. The liquid crystal display method according to claim 8, wherein said step of changing the ratio of the lightening period and the non-lightening period of said light part includes changing a transmittance or no-transmittance of a shutter element provided on said backlight or on a front side of said liquid crystal panel.

11. The liquid crystal display method according to claim 8, wherein said step of changing the ratio of the display period and the non-display period of said image includes changing a ratio of a period when the image display signal, which corresponds to said image signal is supplied and a period when the black display signal is supplied to said liquid crystal panel.

12. The liquid crystal display method according to claim 8, wherein said step of changing the ratio of the display period and the non-display period of said image includes changing a ratio of a lightening period and a non-lightening period of a light part, which lightens said liquid crystal panel from back side.

13. The liquid crystal display method according to claim 12, wherein said step of changing the ratio of the lightening period and the non-lightening period of said light part includes changing a lightening or no-lightening of a backlight provided on a back side of said liquid crystal panel.

14. The liquid crystal display method according to claim 12, wherein said step of changing the ratio of the lightening period and the non-lightening period of said light part includes changing a transmittance or no-transmittance of a shutter element provided on said backlight or on a front side of said liquid crystal panel.

15. The liquid crystal display method according to claim 1, wherein said step of changing the ratio of the display period and the non-display period of said image includes:

a first step of supplying first to m-th (m is an integer of two or more) signals to a signal line; and

a second step of displaying an image on a liquid crystal panel based on said first to m-th signals to a pixel,

and said first step includes;

supplying said second to m-th signals to said signal lien n times (n is an integer of two or more), for a period until said first signal is written again after said first signal is written to a same pixel,

and said second step includes;

selecting k-th (k is an integer from one or more to n or less) said second to m-th signal; and

writing it to said pixel.

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

said signal line driving circuit supplies said image signal for p gray-scales (p is an integer of two or more),

said first signal and said second signal are image signals to display the image for p gray-scales, respectively,

a multi gray-scale display method that 2p gray-scale display is performed is used over 1 frame period when a still image is displayed, and

a high refreshing rate display method is used by displaying the image with the time difference when a motion image is displayed.

17. The liquid crystal display method according to claim 15, wherein said first to m-th signals are supplied to said signal line continuously, periodically and repeatedly.

18. The liquid crystal display method according to claim 17, wherein

said signal line driving circuit supplies said image signal for p gray-scales (p is an integer of two or more),

said first signal and said second signal are image signals to display the image for p gray-scales, respectively,

a multi gray-scale display method that 2p gray-scale display is performed is used over 1 frame period when a still image is displayed, and

a high refreshing rate display method is used by displaying the image with the time difference when a motion image is displayed.

19. The liquid crystal display method according to claim 17, wherein said first signal is an image signal to display the image, and said second signal is a reset signal.

20. The liquid crystal display method according to claim 19, wherein

said signal line driving circuit supplies said image signal for p gray-scales (p is an integer of two or more),

said first signal and said second signal are image signals to display the image for p gray-scales, respectively,

a multi gray-scale display method that 2p gray-scale display is performed is used over 1 frame period when a still image is displayed, and

a high refreshing rate display method is used by displaying the image with the time difference when a motion image is displayed.

21. The liquid crystal display method according to claim 17, wherein said first signal is an image signal to display the image, and said second signal is a black display signal.

22. The liquid crystal display method according to claim 17, wherein said first signal is an image signal to display the image and said second signal is a gray-scale offset signal.

23. The liquid crystal display method according to claim 1, comprising:

deciding whether a frame image is a motion image or a still image based on the image signal and the synchronizing signal; and

changing the ratio of the display period and the no-display period of said image based on said decision result.

24. The liquid crystal display method according to claim 1, wherein

said step of changing the ratio of the display period and the no-display period of said image includes dividing said image signal of 1 frame into a plurality of areas and changing the ratio of the display period and the no-display period of each of the plurality of areas.

25. The liquid crystal display method according to claim 8, wherein

said step of detecting a maximum brightness level of said image signal includes dividing 1 frame of said image signal into a plurality of areas and detecting a maximum brightness level of said image signal in each of said plurality of areas.

26. The liquid crystal display method according to claim 1, wherein

said liquid crystal display device has a scanning line, a plurality of pixels formed on an intersection with the signal line formed to intersect with said scanning line is arranged in a matrix,

said pixel is a first pixel which changes the transmitting light according to an image signal of a first polarity and shield a light by an image signal of a second polarity or a second pixel which changes the transmitting light according to an image signal of a second polarity and shield a light by an image signal of a first polarity,

either one of said first pixel or said second pixel is arranged along a direction of said scanning line,

said first pixel and said second pixel alternately are arranged to directional of said signal line, and

the image is written by applying the image signal of said first polarity to said first pixel, and applying the image signal of said second polarity to said second pixel.

27. The liquid crystal display method according to claim 26, wherein one of the image signal of said first polarity and the image signal of said second polarity is applied to said first pixel and said second pixel connected with one of said signal line at the same time.

28. The liquid crystal display method according to claim 27, wherein

the image signal of said first polarity is a writing signal of said first pixel and an erase signal of said second pixel;

and

the image signal of said second polarity is an erase signal of said first pixel and a writing signal of the second said pixel.