Liquid crystal display device and operating method thereof

• US 20060208985A1
• Filed: 12/07/2005
• Published: 09/21/2006
• Est. Priority Date: 12/07/2004
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Kim, Sangho, Hwang, Hanwook
• Granted Patent: US 8,248,336 B2
• Time in Patent Office: Days
• US Class Current: 345/92
• 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 3/3655 Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors

Abstract

A liquid crystal display device includes one or more data line on a substrate; first and second gate lines crossing the one or more data line to form first and second pixels, the one or more data line providing an image signal to a first electrode of each of the first and second pixels, and the first and second gate lines providing first and second scan signals to the first and second pixels, respectively; a first common voltage unit corresponding to the first gate line, the first common voltage unit for selectively applying a first common voltage to a second electrode of the first pixel via a first common voltage line in accordance with one of the first and second scan signals; and a second common voltage unit corresponding to the second gate line, the second common voltage unit for selectively applying a second common voltage to a second electrode of the second pixel via a second common voltage line in accordance with another one of the first and second scan signals.

Claims

1. A liquid crystal display device, comprising:

one or more data line on a substrate;

first and second gate lines crossing the one or more data line to form first and second pixels, the one or more data line providing an image signal to a first electrode of each of the first and second pixels, and the first and second gate lines providing first and second scan signals to the first and second pixels, respectively;

a first common voltage unit corresponding to the first gate line, the first common voltage unit for selectively applying a first common voltage to a second electrode of the first pixel via a first common voltage line in accordance with one of the first and second scan signals; and

a second common voltage unit corresponding to the second gate line, the second common voltage unit for selectively applying a second common voltage to a second electrode of the second pixel via a second common voltage line in accordance with another one of the first and second scan signals.

2. The liquid crystal display device of claim 1, wherein the second common voltage unit is controlled by the first scan signal from the first gate line.

3. The liquid crystal display device of claim 1, wherein the first common voltage unit is controlled by the first scan signal from the first gate line and the second common voltage unit is controlled by the second scan signal from the second gate line.

4. The liquid crystal display device of claim 2, wherein the second common voltage unit includes:

first and second transistors driven by the first scan signal from the first gate line, the first and second transistors for transferring or blocking first and second control signals; and

third and fourth transistors whose gate electrodes are connected to drain electrodes of the first and second transistors, respectively, one of the third and fourth transistors selectively turned on by one of the first and second control signals selectively transferred by one of the first and second transistors, and applying one of the first and second common voltages to the second common voltage line.

5. The liquid crystal display device of claim 4, wherein the first control signal and the second control signal are applied to the first transistor and second transistor in a reverse order.

6. The liquid crystal display device of claim 4, wherein the first and second transistors are of the same type.

7. The liquid crystal display device of claim 4, wherein the third and fourth transistors are of the same type.

8. The liquid crystal display device of claim 4, wherein the first and second control signals have potentials different from each other at each frame period.

9. The liquid crystal display device of claim 4, wherein each of the first and second control signals has a potential changing at each frame period.

10. The liquid crystal display device of claim 4, wherein the first common voltage is different from the second common voltage.

11. The liquid crystal display device of claim 4, wherein the second common voltage unit is additionally provided with first and second capacitors respectively connected to gate electrodes of the third and fourth transistors for storing the first and second control signals and respectively providing the first and second control signals to the third and fourth transistors during one frame period.

12. The liquid crystal display device of claim 1, wherein the image signal provided to the first pixel has a different potential from the selectively applied one of the first and second common voltages.

13. The liquid crystal display device of claim 3, wherein the second common voltage unit includes:

first and second transistors driven by the second scan signal from the second gate line, the first and second transistors for transferring or blocking first and second control signals; and

third and fourth transistors whose gate electrodes are connected to drain electrodes of the first and second transistors, respectively, one of the third and fourth transistors selectively turned on by one of the first and second control signals selectively transferred by one of the first and second transistors, and applying one of the first and second common voltages to the second common voltage line.

14. The liquid crystal display device of claim 13, wherein the first control signal and the second control signal are applied to the first transistor and second transistor in a reverse order.

15. The liquid crystal display device of claim 13, wherein the first and second transistors are of the same type.

16. The liquid crystal display device of claim 13, wherein the third and fourth transistors are of the same type.

17. The liquid crystal display device of claim 13, wherein the first and second control signals have potentials different from each other at each frame period.

18. The liquid crystal display device of claim 13, wherein each of the first and second control signals has a potential changing at each frame period.

19. The liquid crystal display device of claim 13, wherein the first common voltage is different from the second common voltage.

20. The liquid crystal display device of claim 13, wherein the second common voltage unit is additionally provided with first and second capacitors respectively connected to gate electrodes of the third and fourth transistors for storing the first and second control signals and respectively providing the first and second control signals to the third and fourth transistors during one frame period.

21. A liquid crystal display device, comprising:

a plurality of pixels arranged on a substrate;

a plurality of data lines and gate lines arranged on the substrate to form a matrix;

a first electrode and a second electrode provided on the respective pixels;

a plurality of common voltage units corresponding to the gate lines and selectively outputting a first common voltage or a second common voltage according to a scan signal applied via the gate lines; and

common electrodes and pixel electrodes respectively provided at the pixels for forming a horizontal electric field within the pixel, the common electrodes receiving a first common voltage or a second common voltage applied from the common voltage units, and the pixel electrodes receiving an image voltage applied via the data lines.

22. A liquid crystal display device, which displays an image by driving a liquid crystal material by a difference between a common voltage and an image voltage, comprising:

a substrate;

a plurality of rows of pixels arranged on the substrate;

a gate driving unit sequentially applying a scan signal to each of the rows of pixels;

a data driving unit applying an image voltage to the pixels in each row selected by the scan signal; and

a plurality of common voltage units provided at each row of pixels, each common voltage unit being driven by the scan signals applied to a previous row of pixels to charge a common voltage into a current row of pixels.

23. The liquid crystal display device of claim 22, wherein adjacent rows of pixels are provided with different common voltages.

24. The liquid crystal display device of claim 22, wherein the image voltage outputted from the data driving unit has a different potential from the common voltage applied to the corresponding row of pixels.

25. A method of driving a liquid crystal display device, comprising:

providing an image signal to a first electrode of each of first and second pixels through one or more data line;

providing first and second scan signals to the first and second pixels respectively through first and second gate lines;

selectively applying a first common voltage outputted by a first common voltage unit corresponding to the first gate line to a second electrode of the first pixel via a first common voltage line in accordance with one of the first and second scan signals; and

selectively applying a second common voltage outputted by a second common voltage unit corresponding to the second gate line to a second electrode of the second pixel via a second common voltage line in accordance with another one of the first and second scan signals.

26. The method of claim 25, further comprising controlling the second common voltage unit by the scan signal from the first gate line.

27. The method of claim 25, further comprising controlling the first common voltage unit by the scan signal from the first gate line and controlling the second common voltage unit by the scan signal from the second gate line.

28. The method of claim 25, further comprising:

selectively transferring or blocking first and second control signals to selectively turning on one of first and second switching devices provided in the second common voltage unit;

and applying one of the first and second common voltages through the selectively turned on one of first and second switching devices to the second common voltage line for generating an horizontal electric field in the pixel.