LCD device capable of controlling a viewing angle and method for driving the same

• US 7,800,570 B2
• Filed: 06/29/2006
• Issued: 09/21/2010
• Est. Priority Date: 12/29/2005
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Jang, Hyung Seok, Jin, Hyun Suk
• Primary Examiner(s): Shalwala; Bipin
• Assistant Examiner(s): CRAWLEY, KEITH L
• Application Number:
  US11/478,977
• Publication Number:
  US 20070152930A1
• Time in Patent Office: 1,545 Days
• Field of Search: 345 87-104, 345/690, 345/629, 349 49-102
• US Class Current: 345/94
• CPC Class Codes: G02F 1/1323 Arrangements for providing a switchable viewing angle
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2320/028 by changing the viewing angle properties, e.g. widening the viewing angle, adapting the viewing angle to the view direction
• CPC Class Codes: G09G 3/2018 by time modulation using two or more time intervals
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

An LCD device is disclosed in which the LCD device is driven in an FFS mode and a VAC mode during a frame frequency period to obtain a narrow viewing angle. The method for driving the LCD device includes driving the LCD device in an FFS mode during a frame frequency period to obtain a wide viewing angle, and driving the LCD device in both the FFS mode and a VAC mode during the frame frequency period by dividing the frame frequency period, thereby obtaining a narrow viewing angle.

Claims

1. A method for driving an LCD device capable of controlling a viewing angle comprising:

driving the LCD device in an fringe field switching (FFS) mode during a frame frequency period to obtain a wide viewing angle; and

driving the LCD device in both the FFS mode and a viewing angle control (VAC) mode during the frame frequency period by dividing the frame frequency period, thereby obtaining a narrow viewing angle;

wherein the LCD device comprises a plurality of pixel electrodes formed on a first substrate, a plurality of first common electrodes formed on the first substrate including the pixel electrodes, and a plurality of second common electrodes formed on a second substrate bonded to the first substrate by interposing a liquid crystal layer in between; and

wherein driving the LCD device in both the FFS mode and the VAC mode comprises driving the liquid crystal layer by a vertical electric field formed between the first common electrodes and the second common electrodes when driving the LCD device in the VAC mode.

2. The method of claim 1, wherein dividing the frame frequency period comprises dividing the frequency period of the VAC mode to be approximately 1/3 or less of the frame frequency period of the FFS mode.

3. The method of claim 1, wherein driving the LCD device in both the FFS mode and the VAC mode comprises inserting frames of the VAC mode among frames of the FFS mode during the frame frequency period.

4. The method of claim 1, wherein driving the LCD device in both the FFS mode and the VAC mode comprises providing frames of the VAC mode after providing frames of the FFS mode during the frame frequency period.

5. The method of claim 1, wherein driving the LCD device in both the FFS mode and the VAC mode comprises providing frames of the VAC mode before providing frames of the FFS mode during the frame frequency period.

6. The method of claim 1, wherein driving the LCD device in both the FFS mode and the VAC mode comprises dividing frames provided during the frame frequency period into sub-frames and driving the sub-frames in both the FFS mode and the VAC mode.

7. The method of claim 6, wherein one set of sub-frames are driven in the VAC mode and a second set of sub-frames are driven in the FFS mode.

8. The method of claim 6, wherein the sub-frames driven in the VAC mode are driven in a sequential scan manner.

9. The method of claim 1, wherein 75 frames per second are provided during the frame frequency period.

10. The method of claim 9, wherein driving the LCD device in both the FFS mode and the VAC mode comprises driving 60 frames in the FFS mode and driving 15 frames in the VAC mode.

11. The method of claim 1, wherein 120 frames per second are provided during the frame frequency period.

12. The method of claim 11, wherein driving the LCD device in both the FFS mode and the VAC mode comprises driving 80 frames in the FFS mode and driving 40 frames in the VAC mode.

13. The method of claim 1, wherein driving the LCD device in the FFS mode comprises driving the liquid crystal layer by a fringe field formed between the pixel electrodes and the first common electrodes.

14. The method of claim 13, wherein driving the LCD device in the FFS mode comprises electrically floating the second common electrodes.

15. The method of claim 1, wherein a potential difference of 1V˜

4V or −

4V˜

−

1V is formed between the first common electrodes and the second common electrodes when driving the LCD device in the VAC mode.

16. The method of claim 1, wherein the pixel electrodes are electrically floated and a voltage equal to a signal applied to the first common electrodes is applied to the pixel electrodes.

17. The method of claim 1, wherein the pixel electrodes are electrically floated and a voltage equal to a pixel voltage less than a threshold voltage is applied to the pixel electrodes.

18. The method of claim 1, wherein the liquid crystal layer is horizontally twisted in the FFS mode and vertically tilted in the VAC mode.

19. A liquid crystal display device capable of controlling a viewing angle comprising:

a plurality of gate and data lines crossing each other on a first substrate to define a plurality of sub-pixels;

a plurality of thin film transistors arranged at each crossing portion where the gate lines cross the data lines;

a plurality of plate type first common electrodes formed in the sub-pixels on the first substrate;

a plurality of pixel electrodes connected to the thin film transistors, formed on the first substrate including the first common electrodes, and insulated from the first common electrodes, in which at least one slit formed;

a second substrate bonded to the first substrate by interposing a liquid crystal layer in between;

a plurality of plate type second common electrodes formed on the second substrate; and

,

a driving mechanism coupled with the first common electrodes and one of a second common electrodes or one of a pixel electrodes, wherein

the driving mechanism is operative to drive the LCD device in a fringe field switching (FFS) mode during a frame frequency period to obtain a wide viewing angle;

the driving mechanism is further operative to drive the LCD device in both the FFS mode and a viewing angle control (VAC) mode during the frame frequency period by dividing the frame frequency period, thereby obtaining a narrow viewing angle; and

the driving mechanism drives the LCD device in both the FFS mode and the VAC mode by driving the liquid crystal layer by a vertical electric field formed between the first common electrodes and the second common electrodes when driving the LCD device in the VAC mode.

20. The liquid crystal display device of claim 19, wherein dividing the frame frequency period comprises dividing the frequency period of the VAC mode to be approximately 1/3 or less of the frame frequency period of the FFS mode.

21. The liquid crystal display device of claim 19, wherein the driving mechanism drives the LCD device in both the FFS mode and the VAC mode by inserting frames of the VAC mode among frames of the FFS mode during the frame frequency period.

22. The liquid crystal display device of claim 19, wherein the driving mechanism drives the LCD device in both the FFS mode and the VAC mode by providing frames of the VAC mode after providing frames of the FFS mode during the frame frequency period.

23. The liquid crystal display device of claim 19, wherein the driving mechanism drives the LCD device in both the FFS mode and the VAC mode by providing frames of the VAC mode before providing frames of the FFS mode during the frame frequency period.

24. The liquid crystal display device of claim 19, wherein the driving mechanism drives the LCD device in both the FFS mode and the VAC mode by dividing frames provided during the frame frequency period into sub-frames and driving the sub-frames in both the FFS mode and the VAC mode.

25. The liquid crystal display device of claim 24, wherein one set of sub-frames are driven in the VAC mode and a second set of sub-frames are driven in the FFS mode.

26. The liquid crystal display device of claim 24, wherein the sub-frames driven in the VAC mode are driven in a sequential scan manner.

27. The liquid crystal display device of claim 19, wherein 75 frames per second are provided during the frame frequency period.

28. The liquid crystal display device of claim 27, wherein the driving mechanism drives the LCD device in both the FFS mode and the VAC mode by driving 60 frames in the FFS mode and driving 15 frames in the VAC mode.

29. The liquid crystal display device of claim 19, wherein 120 frames per second are provided during the frame frequency period.

30. The liquid crystal display device of claim 29, wherein the driving mechanism drives the LCD device in both the FFS mode and the VAC mode by driving 80 frames in the FFS mode and driving 40 frames in the VAC mode.

31. The liquid crystal display device of claim 19, wherein the sub-pixels comprise R sub-pixels that display a red color, G sub-pixels that display a green color, and B sub-pixels that display a blue color.

32. The liquid crystal display device of claim 19, wherein the driving mechanism drives the LCD device in the FFS mode by driving the liquid crystal layer by a fringe field formed between the pixel electrodes and the first common electrodes.

33. The liquid crystal display device of claim 32, wherein the driving mechanism drives the LCD device in the FFS mode by electrically floating the second common electrodes.

34. The liquid crystal display device of claim 19, wherein a potential difference of 1V˜

4V or −

4V˜

−

1V is formed between the first common electrodes and the second common electrodes when driving the LCD device in the VAC mode.

35. The liquid crystal display device of claim 19, wherein the pixel electrodes are electrically floated and a voltage equal to a signal applied to the first common electrodes is applied to the pixel electrodes when driving the LCD device in the VAC mode.

36. The liquid crystal display device of claim 19, wherein the pixel electrodes are electrically floated and a voltage equal to a pixel voltage less than a threshold voltage is applied to the pixel electrodes when driving the LCD device in the VAC mode.

37. The liquid crystal display device of claim 19, wherein the liquid crystal layer is horizontally twisted in the FFS mode and vertically tilted in the VAC mode.