Liquid crystal display capable of compensating feed-through voltage and driving method thereof

• US 7,800,569 B2
• Filed: 03/21/2007
• Issued: 09/21/2010
• Est. Priority Date: 08/18/2006
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Chen, Shyh-feng, Tseng, Kuei-sheng
• Primary Examiner(s): Nguyen; Chanh
• Assistant Examiner(s): Karimi; Pegeman
• Application Number:
  US11/689,131
• Publication Number:
  US 20080042949A1
• Time in Patent Office: 1,280 Days
• Field of Search: 345 86- 95, 349/42
• US Class Current: 345/92
• 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 2300/0876 Supplementary capacities in pixels having special driving circuits and electrodes instead of being connected to common electrode or ground; Use of additional capacitively coupled compensation electrodes
• CPC Class Codes: G09G 2320/0219 Reducing feedthrough effects in active matrix panels, i.e. voltage changes on the scan electrode influencing the pixel voltage due to capacitive coupling
• 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 3/3659 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 includes a gate driver, a source driver, a plurality of scan lines, a plurality of data lines, and a plurality of pixel units arranged in an array. The gate driver is used for generating scan signals. The scan signals include a first voltage level, a second voltage level greater than the first voltage level, and a third voltage level less than the first voltage level. The source driver is used for generating data signals. The plurality of scan lines includes a first scan line, a second scan line, and a third scan line, for delivering the scan signals. The plurality of data lines includes a first data line for delivering the data signals. Each pixel unit includes a first pixel electrode, a first transistor, a second pixel electrode, a second transistor, and a level adjustment unit.

Claims

1. A liquid crystal display (LCD) comprising

a gate driver for generating scan signals, the scan signals comprising a first voltage level, a second voltage level greater than the first voltage level, and a third voltage level less than the first voltage level;

a source driver for generating data signals;

a plurality of scan lines comprising a first scan line, a second scan line, and a third scan line, for delivering the scan signals;

a plurality of data lines comprising a first data line for delivering the data signals;

a plurality of pixel units arranged in an array, each pixel unit comprising;

a first pixel electrode;

a first transistor, electrically coupling the first pixel electrode, the first data line, and the second scan line, for conducting the data signals from the first data line to the first pixel electrode when the scan signal from the second scan line is at the second voltage level;

a second pixel electrode;

a second transistor, electrically coupling the second pixel electrode and a first pixel electrode of a pixel unit which is electrically coupled to the third scan line and the first data line, for conducting the data signals, through the first pixel electrode of the pixel unit which is electrically coupled to the third scan line and the first data line, to the second pixel electrode, when scan signals from the second scan line and the third scan line are at the second voltage level; and

a level adjustment unit directly connected to the second pixel electrode and directly connected to the first scan line, for adjusting a voltage applied on the second pixel electrode, when the scan signal from the second scan line is at the second voltage level, and when a scan signal from the first scan line is varied from the third voltage level to the first voltage level.

2. The liquid crystal display of claim 1, wherein the level adjustment unit is a capacitor.

3. The liquid crystal display of claim 2, wherein the level adjustment unit is used for adjusting the voltage applied on the second pixel electrode in response to a capacitance of the level adjustment unit, when the scan signal from the second scan line is at the second voltage level, and when the scan signal from the first scan line is varied from the third voltage level to the first voltage level.

4. The liquid crystal display of claim 2, wherein the level adjustment unit is charged, when the scan signal from the second scan line is at the second voltage level, and the scan signal from the first scan line is at the third voltage level.

5. A liquid crystal display, comprising:

a gate driver for generating scan signals, the scan signals comprising a first voltage level, a second voltage level greater than the first voltage level, and a third voltage level less than the first voltage level;

a source driver for generating data signals;

a plurality of scan lines comprising an first scan line, an second scan line, and an third scan line, for delivering the scan signals;

a plurality of data lines comprising a first data line for delivering the data signals;

a plurality of pixel units arranged in an array, each pixel unit comprising;

a first pixel electrode;

a first transistor, electrically coupling the first pixel electrode, the first data line and the second scan line, for conducting the data signals from the first data line to the first pixel electrode when the scan signal from the second scan line is at the second voltage level;

a second pixel electrode;

a second transistor, electrically coupling the second pixel electrode and a first pixel electrode of a pixel unit which is electrically coupled to the third scan line and the first data line, for conducting the data signals through the first pixel electrode of the pixel unit which is electrically coupled to the third scan line and the first data line, to the second pixel electrode, when the scan signals from the second scan line and the third scan line are at the second voltage level;

a first level adjustment unit directly connected to the second pixel electrode and directly connected to a gate of a second transistor of the pixel unit which is electrically coupled to the first scan line and the first data line, for adjusting the voltage applied on the second pixel electrode, when the scan signal from the second scan line is at the third voltage level, and when a scan signal from the first line is varied from the third voltage level to the first voltage level; and

a second level adjustment unit for adjusting the voltage applied on the first pixel electrode, when the scan signal from the second scan line is at the third voltage level, and when the scan signal from the first scan line is varied from the third voltage level to the first voltage level.

6. The liquid crystal display of claim 5, wherein the first level adjustment unit is a capacitor.

7. The liquid crystal display of claim 6, wherein the first level adjustment unit is used for adjusting the voltage applied on the second pixel electrode in response to a capacitance of the first level adjustment unit, when the scan signal from the second scan line is at the third voltage level, and when the scan signal from the first scan line is varied from the third voltage level to the first voltage level.

8. The liquid crystal display of claim 6, wherein the first level adjustment unit is charged, when the scan signal from the second scan line is at the second voltage level, and the scan signal from the first scan line is at the third voltage level.

9. The liquid crystal display of claim 5, wherein the second level adjustment unit is coupled to the first pixel electrode and a gate of the second transistor of the pixel unit which is electrically coupled to the first scan line and the first data line.

10. The liquid crystal display of claim 9, wherein the second level adjustment unit is a capacitor.

11. The liquid crystal display of claim 10, wherein the second level adjustment unit is used for adjusting the voltage applied on the first pixel electrode in response to a capacitance of the second level adjustment unit, when the scan signal from the second scan line is at the third voltage level, and when the scan signal from the first scan line is varied from the third voltage level to the first voltage level.

12. The liquid crystal display of claim 9, wherein the second level adjustment unit is charged, when the scan signal from the second scan line is at the second voltage level, and the scan signal from the first scan line is at the third voltage level.

13. A method of driving a liquid crystal display, the liquid crystal display comprising a plurality of scan lines, a plurality of data lines, and a plurality of pixel units arranged in an array, the plurality of scan lines comprising a first scan line, a second scan line, and a third scan line, the plurality of data lines comprising a first data line, each pixel unit comprising a first pixel electrode and a second pixel electrode, the method comprising:

providing scan signals, the scan signals comprising a first voltage level, a second voltage level greater than the first voltage level, and a third voltage level less than the first voltage level;

conducting the data signal to the second electrode of a pixel unit which is electrically coupled to the second scan line and the first data line, through a first pixel electrode of a pixel unit which is electrically coupled to the first scan line and the first data line to the second pixel electrode, when the scan signals from the second scan line and the third scan line are at the second voltage level; and

adjusting a voltage applied on the second pixel electrode in response to a capacitance of a capacitor directly connected to the first scan line and directly connected to the second pixel electrode of the pixel unit which is electrically coupled to the second scan line and the first data line, when the scan signal from the second scan line is at the second voltage level, and when the scan signal from the first scan line is varied from the third voltage level to the first voltage level.

14. The method of claim 13, further comprising:

transmitting data signals to the first pixel electrode of the pixel unit which is electrically coupled to the second scan line and the first data line, when the scan signal from the second scan line is at the second voltage level.

15. The method of claim 13, further comprising:

charging the capacitor, when the scan signal from the second scan line is at the second voltage level, and when the scan signal from the first scan line is at the third voltage level.

16. A method of driving a liquid crystal display, the liquid crystal display comprising a plurality of scan lines, a plurality of data lines, and a plurality of pixel units arranged in an array, the plurality of scan lines comprising a first scan line, a second scan line, and a third scan line, the plurality of data lines comprising a first data line, each pixel unit comprising a first pixel electrode and a second pixel electrode, the method comprising:

providing scan signals, the scan signals comprising a first voltage level, a second voltage level greater than the first voltage level, and a third voltage level less than the first voltage level;

conducting the data signal to the second electrode of a pixel unit which is electrically coupled to the second scan line and the first data line, through a first pixel electrode of a pixel unit which is electrically coupled to the first scan line and the first data line to the second pixel electrode, when the scan signals from the second scan line and the third scan line are at the second voltage level; and

adjusting voltage applied on the first pixel electrode via a second capacitor directly connected to the first pixel electrode and directly connected to a gate of the second transistor which is electrically coupled to the first scan line and the first data line, and adjusting voltage applied on the second pixel electrode directly connected to the second pixel electrode and directly connected to a gate of a second transistor of the pixel unit which is electrically coupled to the first scan line and the first data line, when the scan signal from the second scan line is at the second voltage level, and when the scan signal from the first scan line is varied from the third voltage level to the first voltage level.

17. The method of claim 16, wherein the capacitance of the first capacitor and the capacitance of the second capacitor are different.

18. The method of claim 17, further comprising:

transmitting data signals to the first pixel electrode of the pixel unit which is electrically coupled to the second scan line and the first data line, when the scan signal from the second scan line is at the second voltage level.

19. The method of claim 16, further comprising:

charging the first and the second capacitors, when the scan signal from the second scan line is at the second voltage level, and when the scan signal from the first scan line is at the third voltage level.