Display apparatus

• US 6,750,841 B2
• Filed: 08/05/2002
• Issued: 06/15/2004
• Est. Priority Date: 03/30/1999
• Status: Expired due to Term

• Current Assignee: Japan Display Central Incorporated (Japan Display Incorporated)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Watanabe, Toshiaki, Kobayashi, Hitoshi, Ida, Takashi, Itoh, Goh, Okumura, Haruhiko, Chujoh, Takeshi, Kikuchi, Yoshihiro, Nagai, Takeshi, Yamaguchi, Noboru, Fujiwara, Hisao, Sambonsugi, Yoko, Furukawa, Rieko
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): Dinh, Duc Q
• Application Number:
  US10/211,563
• Publication Number:
  US 20020190940A1
• Time in Patent Office: 680 Days
• Field of Search: 345/92, 345/98-100, 345/214
• US Class Current: 345/100
• CPC Class Codes: G09G 2300/0814 used for selection purposes, e.g. logical AND for partial update
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2320/0257 Reduction of after-image effects
• 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 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• 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 apparatus comprising a display panel having a plurality of pixels arranged in a matrix, signals lines for inputting a video signal to the plurality of pixels, and switching elements for selecting the pixels individually, a video decoder which decodes input compressed video data to obtain a reconstructed picture signal for each frame, a change region detector for detecting a change region between a previous frame and a current frame by using the reconstructed picture signal, to obtain address data on the change region, a display signal converter for converting the reconstructed picture signal into a display picture signal, a difference signal detector for detecting a difference signal indicating at least a difference between the previous frame and the current frame, a switch driver for selectively driving the switching elements to select the pixels corresponding to the change region in accordance with the address data, and a signal line driver for adding the difference signal and the display picture signal of the previous frame, and inputting an addition result to the signal lines.

Claims

1. A display method for displaying on an active matrix type display having a plurality of pixels arranged in a matrix, signal lines for inputting a video signal to the plurality of pixels, and switching elements configured to select the plurality of pixels individually, the display method comprising:

decoding input compressed video data to obtain a reconstructed picture signal for each picture;

detecting a change region between a previous picture and a current picture by using the reconstructed picture signal to obtain address data on the change region;

converting the reconstructed picture signal into a display picture signal;

detecting a difference signal indicating at least a difference between the previous picture and the current picture;

selecting the pixels corresponding to the change region in accordance with the address data; and

adding the difference signal and a display picture signal of the previous picture to obtain an addition result which is input to the signal lines as the video signal.

2. A display method according to claim 1, further comprising:

rewriting the pixels in the change region.

3. A display method according to claim 2, wherein the rewriting rewrites the pixels in units of blocks of N×

N pixels corresponding to the change region.

4. A display method according to claim 3, wherein the rewriting rewrites blocks belonging to a change region having a large change amount of the difference signal prior to rewriting other blocks.

5. A display method according to claim 2, wherein the rewriting rewrites the pixels corresponding to the change region in units of lines.

6. A display method according to claim 1, further comprising:

rewriting a portion having a large change region prior to rewriting a portion having a small change region when rewriting the video for unit blocks containing the change region in units of pixels.

7. A display method according to claim 1, further comprising:

displaying the pixels belonging to the change region and the pixels which do not belong to the change region by different gradation display methods.

8. A display method according to claim 7, wherein the displaying displays the pixels which do not belong to the change region by a gradation display method, and the pixels belonging to the change region by a dither scheme.

9. A display method according to claim 1, wherein the switch driver selectively drives the switching elements to input the video signal reflecting in change into the pixels belonging to the change region, and to hold the previous picture for the pixels which do not belong to the change region.

10. A display method according to claim 1, further comprising:

setting a write time for the pixels belonging to the change region longer than a write time for the pixels which do not belong to the change region.

11. A display method according to claim 1, the display panel comprising a liquid crystal display panel containing a liquid crystal material, comprising:

inputting the video signal having a signal amplitude including response characteristics of the liquid crystal material to the pixels belonging to the change region and holding the previous picture for the pixels which do not belong to the change region.

12. A display method according to claim 1, wherein the detecting includes detecting a change region on a picture plane from the difference signal indicating a difference between a reconstructed picture of the previous picture and a reconstructed picture of the current picture.

13. A display method according to claim 1, wherein the detecting includes detecting the change region on a picture plane by using at least one of a coding mode, a conversion coefficient and a magnitude of a motion vector among decoding results.

14. A display method by an active matrix type display panel having a plurality of pixels arranged in a matrix, signal lines for inputting a video signal to the plurality of pixels, and switching elements configured to select the plurality of pixels individually, the method comprising:

decoding compressed video data to obtain a reconstructed picture signal for each picture;

detecting a change region between a previous picture and a current picture by using the reconstructed picture signal obtained by the video decoder to obtain address data on the change region;

converting a reconstructed picture signal of the previous picture and a reconstructed picture signal of the current picture signal into display pixel signals having different amounts of display data between the pixels belonging to the change region and the pixels which do not belong to the change region, respectively;

detecting a difference signal indicating at least a difference between the previous picture and the current picture;

selecting the pixels corresponding to the change region in accordance with the address data; and

adding the difference signal and the display picture signal of the previous picture to obtain an addition result to be supplied to the signal lines as the video signal.

15. A display method according to claim 14, comprising:

inputting the video signal reflecting in change into the pixels belonging to the change region, and holding the previous picture for the pixels which do not belong to the change region.

16. A display method according to claim 14, further comprising:

setting a write time for the pixels belonging to the change region longer than a write time for the pixels which do not belong to the change region.

17. A display method according to claim 14, the display panel comprising a liquid crystal display panel containing a liquid crystal material, the method comprising:

inputting the video signal having a signal amplitude including response characteristics of the liquid crystal material into the pixels belonging to the change region, and holding the previous picture for the pixels which do not belong to the change region.

18. A display method according to claim 14, wherein detecting includes detecting a change region on a picture plane from the difference signal indicating a difference between a reconstructed picture of the previous picture and a reconstructed picture of the current picture.

19. A display method according to claim 14, wherein detecting includes detecting the change region on a picture plane by using at least one of a coding mode, a conversion coefficient and a magnitude of a motion vector among decoding results.

20. A display method by a liquid crystal panel having a plurality of pixels arranged in a matrix, signal lines for inputting a video signal to the plurality of pixels, and switching elements configured to select the plurality of pixels individually, the method comprising:

decoding compressed video data to obtain a reconstructed picture signal for each frame;

detecting a change region between a previous frame and a current frame by using the reconstructed picture signal obtained by the video decoder to obtain address data on the change region;

converting a reconstructed picture signal of the previous frame and a reconstructed picture signal of the current frame into display picture signals, respectively; and

adding the difference signal and the display picture signal of the previous frame, to obtain a display picture signal having display bits for the pixels belonging to the change region of the current frame set fewer than display bits for the pixels belonging to other regions, the display picture signal being input to the signal lines.

21. A display method according to claim 20, wherein the detecting includes detecting a change region on a picture plane from the difference signal indicating a difference between a reconstructed picture of the previous frame and a reconstructed picture of the current frame.

22. A display method according to claim 20, wherein the detecting includes detecting the change region on a picture plane by using at least one of a coding mode, a conversion coefficient and a magnitude of a motion vector among decoding results.

23. A display method according to claim 20, wherein the decoding includes MPEG-4 decoding, and the detecting includes detecting a region in which the reconstructed signal of the previous frame and the reconstructed signal of the current frame have changed.