LCD display with divided pixel electrodes connected separately with respective transistors in one pixel and method of driving which uses detection of movement in video

• US 5,870,075 A
• Filed: 10/23/1995
• Issued: 02/09/1999
• Est. Priority Date: 10/24/1994
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Konuma, Toshimitsu, Nishi, Takeshi, Koyama, Jun, Yamazaki, Shunpei, Nakazawa, Misako
• Primary Examiner(s): Brier, Jeffery
• Assistant Examiner(s): Bell, Paul A.
• Application Number:
  US08/553,726
• Time in Patent Office: 1,205 Days
• Field of Search: 345/43, 345/89, 345/92, 345/98, 345/100, 345/103, 345/149, 345/88, 345/152, 345/204, 345/214, 345/99, 345/93, 349/42, 349/84, 349/85, 349/143, 349/144, 349/146
• US Class Current: 345/92
• CPC Class Codes: G02F 1/13624 having more than one switching element per pixel
• CPC Class Codes: G09G 2300/0443 with several sub-pixels for the same colour in a pixel, not specifically used to display gradations G09G3/364 takes precedence
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2310/0281 Arrangement of scan or data electrode driver circuits at the periphery of a panel not inherent to a split matrix structure
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• 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 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127
• 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

In an active matrix type liquid crystal display device, signal lines and scanning lines are crossed in a matrix form on a transparent substrate. A thin film transistor and a transparent pixel electrode are disposed at each intersecting portion. A liquid crystal is interposed between the transparent substrate and another transparent substrate. A central pixel electrode and a peripheral pixel electrode surrounding the central pixel electrode is arranged in each pixel region. When the pixel region has movement in a dynamic image display, after an electric field is applied to the liquid crystal by the peripheral pixel electrode, an electric field is applied to the liquid crystal by the central pixel electrode with a desired delay time.

Claims

1. An active matrix type liquid crystal display device comprising:

a pair of transparent substrates;

signal lines and scan lines which are formed on one of the transparent substrates and intersected in a matrix form;

a plurality of thin film transistors arranged in intersections of the signal lines and the scan lines;

transparent pixel electrodes connected to the thin film transistors; and

a liquid crystal material disposed between the transparent substrates,

wherein each transparent pixel electrode includes a first pixel electrode arranged in a central portion of one of regions divided by the signal lines and the scan lines and a second pixel electrode surrounding the first pixel electrode, the first and second pixel electrodes are connected to first and second thin film transistors, and the first and second thin film transistors are connected to first and second signal lines and first and second scan lines.

2. The device of claim 1 further comprising driver circuits, and wherein the first and second thin film transistors are driven by first and second driver circuits at different timings through the first and second signal lines and the first and second scan lines.

3. The device of claim 2 wherein the first driver circuit is operated with a first video signal having a delay time corresponding at least one frame period longer than a delay time of a second video signal used to operate the second driver circuit, and the delay time of the first video signal is n-times one frame period (n is integer).

4. The device of claim 3 wherein the second driver circuit is operated with the second video signal when a video signal includes a moving component.

5. A method for driving a display device including a pair of transparent substrates, signal lines and scan lines which are formed on one of the transparent substrates and intersected in a matrix form, a plurality of thin film transistors arranged in intersections of the signal lines and the scan lines, transparent pixel electrodes connected to the thin film transistors, and a liquid crystal material disposed between the transparent substrates, wherein each transparent pixel electrode includes a first pixel electrode arranged in a central portion of one of regions divided by the signal lines and the scan lines and a second pixel electrode surrounding the first pixel electrode, the first and second pixel electrodes are connected to first and second thin film transistors, and the first and second thin film transistors are connected to first and second signal lines and first and second scan lines, the method comprising the steps of:

comparing a video signal to be input with an original video signal;

determining whether a moving component is detected or not in accordance with a comparison result;

driving the first thin film transistor with a previous video signal received before input of the video signal when the moving component is detected; and

driving the second thin film transistor with the input video signal when the moving component is detected,

wherein a period between the input video signal and the previous video signal is one frame period or more.

6. A display device comprising:

a pair of transparent substrates;

signal lines and scan lines which are formed on one of the transparent substrates and intersected in a matrix form;

a plurality of thin film transistors arranged in intersections of the signal lines and the scan lines;

transparent pixel electrode regions connected to the thin film transistors; and

a liquid crystal material disposed between the transparent substrates,

wherein each transparent pixel electrode region applies an electric field to the liquid crystal material and includes a first electrode arranged in a central portion of the transparent pixel electrode region and a second electrode arranged in a peripheral portion of the transparent pixel electrode region, and

wherein a portion of the first electrode and a portion of the second electrode overlap each other, and

wherein the first and second electrodes are connected to first and second thin film transistors, and the first and second thin film transistors are connected to first and second signal lines and first and second scan lines.

7. A display device comprising:

a pair of transparent substrates;

signal lines and scan lines which are formed on one of the transparent substrates and intersected in a matrix form;

a plurality of thin film transistors arranged in intersections of the signal lines and the scan lines;

transparent pixel electrode regions connected to the thin film transistors; and

a liquid crystal material disposed between the transparent substrates,

wherein each transparent pixel electrode region applies an electric field to the liquid crystal material and includes a first electrode arranged in a central portion of the transparent pixel electrode region and a second electrode arranged to surround the first electrode, and

wherein a portion of the first electrode and a portion of the second electrode overlap each other, and

wherein the first and second electrodes are connected to first and second thin film transistors, and the first and second thin film transistors are connected to first and second signal lines and first and second scan lines.

8. An active matrix type liquid crystal display device comprising:

a pair of transparent substrates;

signal lines and scan lines which are formed on one of the transparent substrates and intersected in a matrix form;

a plurality of thin film transistors arranged in intersections of the signal lines and the scan lines;

transparent pixel electrodes connected to the thin film transistors; and

a liquid crystal material disposed between the transparent substrates,

wherein each transparent pixel electrode includes a first pixel electrode arranged in a central portion of one of regions divided by the signal lines and the scan lines and a second pixel electrode surrounding the first pixel electrode, the first and second pixel electrodes are connected to first and second thin film transistors, the first and second thin film transistors are connected to first and second signal lines and first and second scan lines, and the first and second pixel electrodes are formed on different surfaces.

9. The device of claim 8 further comprising driver circuits, and wherein the first and second thin film transistors are driven by first and second driver circuits at different timings through the first and second signal lines and the first and second scan lines.

10. The device of claim 9 wherein the first driver circuit is operated with a first video signal having a delay time corresponding at least one frame period longer than a delay time of a second video signal used to operate the second driver circuit, and the delay time of the first video signal is n-times one frame period (n is integer).

11. The device of claim 10 wherein the second driver circuit is operated with the second video signal when a video signal includes a moving component.

12. A liquid crystal display device comprising:

a plurality of pixel regions; and

driver circuits for driving the pixel regions,

wherein each pixel region comprises,

a first pixel electrode arranged in a central portion of the pixel region, and

a second pixel electrode arranged to surround at least a portion of the first pixel electrode,

wherein a portion of the first pixel electrode and a portion of the second pixel electrode overlap each other, and

wherein the first and second pixel electrodes are connected to first and second thin film transistors, and the first and second thin film transistors are connected to first and second signal lines and first and second scan lines.

13. The device of claim 12 wherein the first and second pixel electrodes are formed on different surfaces.

14. The device of claim 13 wherein the first pixel electrode overlaps the second pixel electrode.

15. A display device comprising:

two scanning lines;

two signal lines;

a pixel having a central pixel electrode and a peripheral pixel electrode which surrounds said central pixel electrode;

a first transistor connected with said peripheral pixel electrode at one of source and drain thereof, and connected with one of said two signal lines at the other of said source and said drain, and connected with one of said two scanning lines at a gate electrode thereof; and

a second transistor connected with said central pixel electrode at one of source and drain of said second transistor, and connected with the other of said two signal lines at the other of said source and drain of said second transistor, and connected with the other of said two scanning lines at a gate electrode of said second transistor.

16. The device of claim 15 wherein said peripheral pixel electrode surrounds at least two sides of said central pixel electrode.

17. A method for driving a display device having a pixel comprising a central pixel electrode and a peripheral pixel electrode which surrounds said central pixel electrode, said method comprising:

applying a first electric field to said peripheral pixel electrode through a first transistor connected with said peripheral pixel electrode at one of source and drain thereof, and connected with one of two signal lines at the other of said source and drain, and connected with one of two scanning lines at a gate electrode thereof;

applying a second electric field to said central pixel electrode through a second transistor connected with said central pixel electrode at one of source and drain of said second transistor, and connected with the other of said two signal lines at the other of said source and drain of said second transistor, and connected with the other of said two scanning lines at a gate electrode of said second transistor.

18. The method of claim 17 wherein said peripheral pixel electrode surrounds at least two sides of said central pixel electrode.

19. The method of claim 17 wherein said second electric field is applied to said central pixel electrode through said second transistor after said first electric field is applied to said peripheral pixel electrode through said first transistor.