Method and apparatus for processing data of liquid crystal display

• US 20070001960A1
• Filed: 06/26/2006
• Published: 01/04/2007
• Est. Priority Date: 06/30/2005
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Kim, Seong, Kwag, Sun
• Granted Patent: US 8,279,150 B2
• Time in Patent Office: Days
• US Class Current: 345/92
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2310/063 Waveforms for resetting the whole screen at once
• 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 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
• CPC Class Codes: G09G 3/3677 suitable for active matrices only

Abstract

A method of driving and a liquid crystal display that are adaptive for preventing a motion blur phenomenon inserting a black data without reducing a data charging time are disclosed. In the liquid crystal display, a first gate line supplies a first scanning signal. A second gate line supplies a second scanning signal. A data line supplies a data signal. A common line supplies a common voltage. A first thin film transistor supplies the data signal in response to the first scanning signal. In a liquid crystal cell, a pixel electrode is connected to the first thin film transistor and a common electrode is connected to the common line. A second thin film transistor supplies the common voltage to the pixel electrode in response to the second scanning signal.

Claims

1. A liquid crystal display, comprising:

a first gate line that supplies a first scanning signal;

a second gate line that supplies a second scanning signal;

a data line that supplies a data signal;

a common line that supplies a common voltage;

a first thin film transistor that supplies the data signal in response to the first scanning signal;

a liquid crystal cell including a pixel electrode connected to the first thin film transistor and a common electrode connected to the common line; and

a second thin film transistor that supplies the common voltage to the pixel electrode in response to the second scanning signal.

2. The liquid crystal display as claimed in claim 1, wherein the second thin film transistor supplies the pixel electrode with the common voltage, after said first thin film transistor allows the data signal to be charged in the pixel electrode and be held.

3. The liquid crystal display as claimed in claim 2, wherein a period of keeping the data signal charged in the pixel electrode by the first thin film transistor is changed by a turning-on time of the second thin film transistor.

4. The liquid crystal display as claimed in claim 3, wherein the period of keeping the data signal charged in the pixel electrode is changed by an average brightness.

5. The liquid crystal display as claimed in claim 4, wherein the period of keeping the data signal charged in the pixel electrode is changed in each frame.

6. The liquid crystal display as claimed in claim 1, wherein said liquid crystal cell includes a liquid crystal of normally black type.

7. The liquid crystal display as claimed in claim 1, wherein said liquid crystal cell includes a liquid crystal of IPS (In plane switching) type.

8. The liquid crystal display as claimed in claim 1, wherein said liquid crystal cell includes a liquid crystal of fringe field switching type.

14. The liquid crystal display as claimed in claim 1, wherein said second gate driver changes the point of supplying the second scanning signal in each frame.

9. A liquid crystal display, comprising:

an image display including a plurality of first gate lines that supply a first scanning signal;

a plurality of second gate lines that supply a second scanning signal;

a plurality of data lines that supply a data signal;

a plurality of common lines that supply a common voltage;

a pixel electrode provided for each pixel area defined by an intersection between the first and second gate line and the data line;

a liquid crystal cell including a common electrode connected to the common line;

a first thin film transistor that supplies the data signal to the pixel electrode in response to the first scanning signal, and a second thin film transistor that supplies the common voltage to the pixel electrode in response to the second scanning signal;

a first gate driver that supplies a plurality of the first scanning signal to a plurality of the first gate lines;

a second gate driver that supplies a plurality of the second scanning signal to a plurality of the second gate lines;

a data driver that drives the data signal to a plurality of the data line; and

a common voltage generator that supplies a plurality of the common lines with a common voltage.

10. The liquid crystal display as claimed in claim 9, wherein said first gate driver sequentially supplies the first scanning signal to a plurality of the first gate line, and

said second gate driver sequentially supplies the second scanning signal to a plurality of the second gate line.

11. The liquid crystal display as claimed in claim 10, wherein said second gate driver, if the first thin film transistor allows the data signal to be charged into the pixel electrode and to be kept for a designated period, supplies the second scanning signal to the second thin film transistor.

12. The liquid crystal display as claimed in claim 11, wherein said second gate driver controls a period to be kept a data signal charged into the pixel electrode by changing a point that the second scanning signal is applied.

13. The liquid crystal display as claimed in claim 12, wherein said second gate driver changes a point of supplying of the second scanning signal in response to an inputted control signal according to an average brightness from outside the display.

15. The liquid crystal display as claimed in claim 9, wherein said liquid crystal cell includes a liquid crystal of normally black type.

16. The liquid crystal display as claimed in claim 9, wherein said liquid crystal cell includes a liquid crystal of IPS (In plane switching) type.

17. The liquid crystal display as claimed in claim 9, wherein said liquid crystal cell includes a liquid crystal of fringe field switching type.

18. A method of driving a liquid crystal display, comprising the steps of:

supplying a data signal of a data line to a pixel electrode of a liquid crystal cell by a first thin film transistor connected to a first gate line; and

supplying a common signal of a common line to the pixel electrode by a second thin film transistor connected to a second gate line.

19. The method as claimed in claim 18, wherein if the first thin film transistor allows the data signal to be charged into the pixel electrode and to be held for a designated period, then the second thin film transistor supplies the common voltage.

20. The method as claimed in claim 19, wherein said second thin film transistor changes a point of supplying the common voltage, to thereby change a period of keeping a data signal charged into the pixel electrode.

21. The method as claimed in claim 19, further comprising the step of:

detecting an average brightness, and

wherein the second thin film transistor according to the average brightness changes a point of supplying the common voltage.

22. The method as claimed in claim 20, wherein a point of supplying the common voltage changes in each frame in the second thin film transistor.

23. The method as claimed in claim 18, wherein said liquid crystal cell drives a liquid crystal of normally black type.

24. The method as claimed in claim 19, wherein said liquid crystal cell drives a liquid crystal of IPS (In plane switching) type.

25. The method as claimed in claim 19, wherein said liquid crystal cell drives a liquid crystal of fringe field switching type.