Liquid crystal display panel, driving method and liquid crystal display

• US 20080018573A1
• Filed: 06/29/2007
• Published: 01/24/2008
• Est. Priority Date: 06/30/2006
• Status: Active Grant

• Current Assignee: InnoLux Corporation
• Original Assignee: Chi Mei Innolux Corporation (InnoLux Corporation)
• Inventors: Hsu, Che-Ming, Hsieh, Chih-Yung, Chen, Chien-Hong, Hsieh, Ming-Feng, Ho, I-Lin
• Granted Patent: US 8,179,344 B2
• Time in Patent Office: Days
• US Class Current: 345/87
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• 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 2300/0465 Improved aperture ratio, e.g. by size reduction of the pixel circuit, e.g. for improving the pixel density or the maximum displayable luminance or brightness
• CPC Class Codes: G09G 2300/0852 being a dynamic memory with more than one capacitor
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

In one embodiment of the invention, a pixel unit has two sub-pixel regions each including a liquid crystal capacitor (LCC) and storage capacitor (SC). The capacitance ratio of the SC to LCC of the first sub-pixel differs from the capacitance ratio of the SC to LCC of the second sub-pixel.

Claims

1. A liquid crystal display device comprising:

a liquid crystal layer;

a pixel having at least a first sub-pixel region and a second sub-pixel region;

first and second pixel electrodes;

a first active device coupled to the first pixel electrode, the first active device in the first sub-pixel region;

a common electrode, the first pixel electrode, and a portion of the liquid crystal layer forming a first liquid crystal capacitor having a first capacitance;

a first storage capacitor line and a first storage capacitor opposite electrode forming a first storage capacitor having a second capacitance;

a second active device coupled to the second pixel electrode, the second active device in the second sub-pixel region, wherein the second pixel electrode, the common electrode and a portion of the liquid crystal layer form a second liquid crystal capacitor having a third capacitance; and

a second storage capacitor line and a second storage capacitor opposite electrode forming a second storage capacitor having a fourth capacitance;

wherein a first ratio of the first capacitance to the second capacitance is unequal to a second ratio of the third capacitance to fourth capacitance.

2. The device of claim 1, further comprising a third storage capacitor line to couple the first storage capacitor line to the second storage capacitor line, the third storage capacitor line including a first portion formed substantially parallel to a first data line.

3. The device of claim 1, wherein the first active device has a first parasitic capacitance and the second active device has second parasitic capacitance, the first parasitic capacitance unequal to the second parasitic capacitance.

4. The device of claim 1, wherein the second capacitance is unequal to the fourth capacitance.

5. The device of claim 1, wherein the first capacitance is unequal to the third capacitance.

6. The device of claim 1, further comprising a third storage capacitor line to couple the first storage capacitor line to the second storage capacitor line, the third storage capacitor line including a first portion and a second portion;

wherein the first pixel electrode includes a first plurality of slits, the second pixel electrode includes a second plurality of slits, and the first portion is formed along the first plurality of slits and the second portion is formed along the second plurality of slits.

7. The device of claim 1, wherein the first storage capacitor opposite electrode is coupled to the first pixel electrode.

8. The device of claim 1, wherein the first storage capacitor opposite electrode extends from the first pixel electrode.

9. A method for driving a liquid crystal display device that includes a first sub-pixel region and a second sub-pixel region, the first sub-pixel region including a first active device coupled to a scan line, a data line, and a first storage capacitor, the second sub-pixel region including a second active device coupled to the scan line, the data line, and a second storage capacitor;

the driving method comprising;

applying a scan signal to the scan line;

applying a data signal to the data line;

applying a compensation signal to the first storage capacitor;

applying the compensation signal to the second storage capacitor; and

switching the compensation signal from a first level to a second level based on the scan signal being switched from a high level to a low level.

10. The method of claim 9, further comprising:

coupling a first storage capacitor electrode to a first storage capacitor line to form the first storage capacitor; and

applying the compensation signal to the first storage capacitor line.

11. The method of claim 9, further comprising driving the liquid crystal display pixel unit using a column inversion mode.

12. The method of claim 9, further comprising driving liquid crystal display pixel unit using a mode chosen from the group consisting of row inversion, pixel inversion, and dot inversion.

13. The method of claim 9, wherein the data signal has a first frequency and the compensation signal has the first frequency.

14. The method of claim 9, further comprising switching the compensation signal to a high level based on the scan signal switching to a low level.

15. The method of claim 14, further comprising switching the scan signal to a low level and applying the data signal at a low gray level with a positive polarity;

the voltage of the data signal being less than a common voltage of the liquid crystal display panel.

16. The method of claim 9, further comprising switching the compensation signal to a low level based on switching the scan signal to a low level.

17. The method of claim 16, further comprising switching the scan signal to a low level and applying the data signal at a low gray level and negative polarity, the voltage of the data signal being greater than a common voltage of the liquid crystal display panel.

18. The method of claim 9, wherein the first sub-pixel region includes a first liquid crystal capacitor and the second sub-pixel region includes a second liquid crystal capacitor, the first storage capacitor having a first capacitance, the first liquid crystal capacitor having a second capacitance, the second storage capacitor having a third capacitance, and the second liquid crystal capacitor having a fourth capacitance, and a first ratio of the first capacitance to the second capacitance not being equal to a second ratio of the third capacitance to the fourth capacitance.

19. A liquid crystal display device, having a plurality of pixel units arranged in an array, wherein each pixel unit has a plurality of sub-pixel regions, and each pixel unit comprises:

a plurality of active devices, each of the plurality of active devices being formed in one of the sub-pixel regions and to electrically connect to a scan line and a data line;

a plurality of liquid crystal capacitors, each of the plurality of liquid crystal capacitors formed in one of the sub-pixel regions and to electrically connect to one of the plurality of active devices; and

a plurality of storage capacitors, each of the plurality of storage capacitors formed in one of the sub-pixel regions and to electrically connect to one of the plurality of active devices;

wherein in a same pixel unit, a ratio of the capacitance of the storage capacitor to that of the liquid crystal capacitor of any sub-pixel region is unequal to a ratio of the capacitance of the storage capacitor to that of the liquid crystal capacitor of any other sub-pixel region.

20. The liquid crystal display device as claimed in claim 19, wherein the active devices in the same pixel unit are to have different parasitic capacitances.

21. The liquid crystal display device as claimed in claim 19, wherein the capacitances of the storage capacitors are to be different.

22. The liquid crystal display device as claimed in claim 19, wherein each of the pixel units further comprises a plurality of storage capacitor opposite electrodes respectively formed in the sub-pixel regions and respectively coupled to a plurality of storage capacitor lines to form the storage capacitors;

and further wherein the pixel electrodes of each pixel unit have a plurality of slits and each storage capacitor line is formed along the corresponding slit.

23. A liquid crystal display device comprising:

a plurality of pixels, wherein each pixel has plural sub-regions containing respective active devices, storage capacitors, and liquid crystal layer capacitors, the storage capacitors having respective storage capacitor capacitances, and the liquid crystal layer capacitors having respective liquid crystal layer capacitances;

wherein in each pixel a ratio of a storage capacitor capacitance to a liquid crystal layer capacitance in one of the sub-regions is different from a ratio of another storage capacitor capacitance to another liquid crystal layer capacitance in another of the sub-regions.