Display apparatus

• US 20020190940A1
• Filed: 08/05/2002
• Published: 12/19/2002
• Est. Priority Date: 03/30/1999
• Status: Active Grant

• Current Assignee: Japan Display Central Incorporated (Japan Display Incorporated)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Watanabe, Toshiaki, Fujiwara, Hisao, Kobayashi, Hitoshi, Ida, Takashi, Itoh, Goh, Okumura, Haruhiko, Chujoh, Takeshi, Kikuchi, Yoshihiro, Nagai, Takeshi, Yamaguchi, Noboru, Sambonsugi, Yoko, Furukawa, Rieko
• Granted Patent: US 6,750,841 B2
• Time in Patent Office: Days
• US Class Current: 345/87
• 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. An active matrix type display apparatus comprising:

an active matrix type 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 configured to select the plurality of pixels individually;

a video decoder configured to decode an input compressed video data and obtain a reconstructed picture signal for each picture;

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

a display signal converter configured to input the reconstructed picture signal, and convert the reconstructed picture signal into a display picture signal;

a difference signal detector configured to input a display picture signal of the previous picture and a display picture of the current picture, and detect a difference signal indicating at least a difference between the previous picture and the current picture;

a switch driver configured to selectively drive the switching elements and select the pixels corresponding to the change region in accordance with the address data obtained by the change region detector; and

a signal line driver configured to add the difference signal obtained by the difference signal detector and the display picture signal of the previous picture, and input an addition result to the signal lines.

2. An active matrix type display apparatus according to claim 1, wherein the display panel includes a plurality of memory elements interposed between the switching elements and the pixels, respectively, and holding the video signal.

3. An active matrix type display apparatus according to claim 1, wherein the display panel includes row address lines and column address lines;

the switch driver comprises a row address line drive circuit configured to drive the row address lines and a column address line drive circuit for driving the column address lines; and

the row address line drive circuit and the column address line drive circuit include rewrite sections configured to supply drive signals to the row address lines and the column address lines in accordance with the address data indicating the change region and for rewriting the pixels in the change region, respectively.

4. An active matrix type display apparatus according to claim 3, wherein the rewrite sections conduct rewrite operation in units of blocks of N×

N pixels corresponding to the change region.

5. An active matrix type display apparatus according to claim 4, wherein the rewrite sections rewrite blocks belonging to a change region having a large change amount of the difference signal prior to rewriting other blocks.

6. An active matrix type display apparatus according to claim 3, wherein the rewrite sections rewrite the pixels corresponding to the change region in units of lines.

7. An active matrix type display apparatus according to claim 1, wherein the switch driver includes a rewrite section configured to rewrite 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.

8. An active matrix type display apparatus according to claim 1, wherein the signal line driver includes a signal processing unit configured to conduct video processing so as to display the pixels belonging to the change region and the pixels which do not belong to the change region by different gradation display methods.

9. An active matrix type display apparatus according to claim 8, wherein the pixels which do not belong to the change region are subjected to video-processing to be displayed by the gradation display method, and the pixels belonging to the change region are subjected to video-processing to be displayed by a dither scheme.

10. An active matrix type display apparatus according to claim 1, wherein the switch driver selectively drives the switching elements for inputting the video signal reflecting on change into the pixels belonging to the change region, and for holding the previous picture for the pixels which do not belong to the change region.

11. An active matrix type display apparatus according to claim 1, further comprising a setting section configured to set 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.

12. An active matrix type display apparatus according to claim 1, wherein the display panel comprises a liquid crystal display panel containing a liquid crystal material;

and the driver selectively drives the switching elements for 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 for holding the previous picture for the pixels which do not belong to the change region.

13. An active matrix type display apparatus according to claim 1, wherein the change region detector is a detector configured to detect 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.

14. An active matrix type display apparatus according to claim 1, wherein the change region detector includes a detecting section configured to detect 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 of the video decoder.

15. An active matrix type display apparatus according to claim 1, wherein the video decoder is a decoder having an MPEG-4 compression encoding system;

and the change region detector inputs shape information reproduced by the decoder, and detects the change region.

17. An active matrix type display apparatus according to claim 16, wherein the display panel includes a plurality of memory elements interposed between the switching elements and the pixels, respectively, and holding the video signal.

18. An active matrix type display apparatus according to claim 16, wherein the switch driver selectively drives the switching elements for inputting the video signal reflecting on change into the pixels belonging to the change region, and for holding the previous picture for the pixels which do not belong to the change region.

19. An active matrix type display apparatus according to claim 16, further comprising a setting section configured to set 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.

20. An active matrix type display apparatus according to claim 16, wherein the display panel comprises a liquid crystal display panel containing a liquid crystal material;

and the switch driver selectively drives the switching elements for 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 for holding the previous picture for the pixels which do not belong to the change region.

21. An active matrix type display apparatus according to claim 16, wherein the change region detector is a detector configured to detect 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.

22. An active matrix type display apparatus according to claim 16, wherein the change region detector includes a detecting section configured to detect 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 of the video decoder.

23. An active matrix type display apparatus according to claim 16, wherein the video decoder is a decoder having an MPEG-4 compression encoding system;

and the change region detector inputs shape information reproduced by the decoder, and detects the change region.

25. A liquid crystal display apparatus according to claim 24, wherein the change region detector includes a detecting section configured to detect 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.

26. A liquid crystal display apparatus according to claim 24, wherein the change region detector includes a detecting section configured to detect 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 of the video decoder.

27. A liquid crystal display apparatus according to claim 24, wherein the video decoder is constructed by an MPEG-4 decoder;

and the change region detector includes a detecting section configured to input shape information reproduced by the video decoder and detect a region in which the reconstructed signal of the previous frame and the reconstructed signal of the current frame have changed.

16. An active matrix type display apparatus comprising:

an active matrix type 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 configured to select the plurality of pixels individually;

a video decoder configured to decode an input compressed video data and obtain a reconstructed picture signal for each picture;

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

a display signal converter configured to input a reconstructed picture signal of the previous picture and a reconstructed picture signal of the current picture signal, and convert the reconstructed picture signals 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;

a difference signal detector configured to input a display picture signal of the previous picture and a display picture of the current picture, and detect a difference signal indicating at least a difference between the previous picture and the current picture;

a switch driver configured to selectively drive the switching elements and select the pixels corresponding to the change region in accordance with the address data obtained by the change region detector; and

a signal line driver configured to add the difference signal obtained by the difference signal detector and the display picture signal of the previous picture, and input an addition result to the signal lines.

24. A liquid crystal display apparatus comprising:

a liquid crystal 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 configured to select the plurality of pixels individually;

a video decoder configured to decode an input compressed video data and obtain a reconstructed picture signal for each frame;

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

a display signal converter configured to input a reconstructed picture signal of the previous frame and a reconstructed picture signal of the current frame, and convert the reconstructed picture signals into display picture signals, respectively;

a switch driver configured to selectively drive the switching elements in accordance with an address signal obtained by the change region detector; and

a signal line driver configured to add the difference signal obtained by the difference signal detector and the display picture signal of the previous frame, 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, and input the display picture signal to the signal lines.