Liquid crystal display and its driving method

• US 6,933,916 B2
• Filed: 12/18/2001
• Issued: 08/23/2005
• Est. Priority Date: 12/19/2000
• Status: Expired due to Term

• Current Assignee: Japan Display Central Incorporated (Japan Display Incorporated)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Suzuki, Daiichi, Kobayashi, Yoshinori, Wakemoto, Hirofumi, Tanaka, Yoshinori, Nakao, Kenji, Sato, Ichiro, Yamakita, Hiroyuki, Kimura, Masanori, Kumagawa, Katsuhiko, Arimoto, Katsuyuki, Shiota, Akinori, Tsuda, Keisuke
• Primary Examiner(s): WU, XIAO MIN
• Application Number:
  US10/130,832
• Publication Number:
  US 20030122767A1
• Time in Patent Office: 1,344 Days
• Field of Search: 345/87, 345/88, 345/89, 345/90, 345/94, 345/95, 345/96, 345/97, 345/98, 345/99, 345/100, 349/33, 349/34, 349/35, 349/37, 349/129, 349/73
• US Class Current: 345/98
• CPC Class Codes: G02F 1/133707 Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes
• CPC Class Codes: G02F 1/134336 Matrix
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 2201/122 having a particular pattern
• CPC Class Codes: G02F 2201/124 interdigital
• CPC Class Codes: G09G 2300/0491 Use of a bi-refringent liquid crystal, optically controlled bi-refringence [OCB] with bend and splay states, or electrically controlled bi-refringence [ECB] for controlling the color
• CPC Class Codes: G09G 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A liquid crystal display of the present invention is adapted to perform initialization by inputting voltages with different polarities to two pixel electrodes (23á, 23â) adjacent in front and back direction. It is preferable that in the two pixel electrodes (23á, 23â) adjacent in front and back direction, the pixel electrode (23á) located on back side is provided with a first protrusion (232á) at a front side and back direction, the pixel electrode (231â) adjacent in front and back is provided with a second protrusion (23â) located on front side is provided with a second a second protrusion (234â) on a back side edge (233â)thereof.

Claims

1. A liquid crystal display comprising:

an array substrate including a plurality of pixel electrodes arranged in front and back direction and in right and left direction and disposed in matrix;

a plurality of source lines and a plurality of gate lines arranged so as to cross each other; and

switching devices provided as corresponding to the respective pixel electrodes and having gate electrodes connected to the gate lines, source electrodes connected to the source lines, and drain electrodes connected to the pixel electrodes, for switching between the source electrodes and the drain electrodes in accordance with a drive signal input to the gate electrodes through the gate lines;

an opposing substrate provided with a counter electrode opposite to the array substrate;

liquid crystal filled between the array substrate and the opposing substrate and having different alignment states in a display state and in a non-display state, the liquid crystal being subjected to initialization from the alignment state in the non-display state to the alignment state in the display state before an image is displayed; and

drive means for performing the initialization by inputting voltages with different polarities to two pixel electrodes adjacent in front and back direction, respectively.

2. The liquid crystal display according to claim 1, wherein the drive means is adapted to apply voltages with different polarities to two pixel electrodes adjacent in right and left direction, respectively.

3. The liquid crystal display according to claim 1, wherein the drive means is adapted to apply voltages with the same polarity to two pixel electrodes adjacent in right and left direction, respectively.

4. The liquid crystal display according to claim 1, wherein the drive means is adapted to apply a constant voltage the counter electrode while applying the voltages to the pixel electrodes.

5. The liquid crystal display according to claim 4, wherein the drive means is adapted to start applying the constant voltage to the counter electrode after start of application of the voltages to the pixel electrodes.

6. The liquid crystal display according to claim 5, wherein the drive means is adapted to start applying the constant voltage to the counter electrode before an elapse of 50 milliseconds after start of application of the voltages to the pixel electrodes.

7. The liquid crystal display according to claim 1, wherein, in the two pixel electrodes adjacent in front and back direction, a pixel electrode located on back side is provided with a first protrusion at a front side edge thereof and a pixel electrode located on front side is provided with a second protrusion at a back side edge thereof.

8. The liquid crystal display according to claim 7, wherein a tip end of the first protrusion is located closer to front than a tip end of the second protrusion.

9. The liquid crystal display according to claim 7, wherein two first protrusions are provided and the second protrusion is located between the two first protrusions.

10. The liquid crystal display according to claim 7, wherein a plurality of first protrusions and a plurality of second protrusions are provided and one of the second protrusions is interposed between adjacent two first protrusions.

11. The liquid crystal display according to claim 1, wherein the liquid crystal is OCB-mode liquid crystal.

12. A liquid crystal display comprising:

an array substrate including a plurality of pixel electrodes arranged in front and back direction and in right and left direction and disposed in matrix;

a plurality of source lines and a plurality of gate lines arranged so as to cross each other; and

switching devices provided as corresponding to the respective pixel electrodes and having gate electrodes connected to the gate lines, source electrodes connected to the source lines, and drain electrodes connected to the pixel electrodes, for switching between the source electrodes and the drain electrodes in accordance with a drive signal input to the gate electrodes through the gate lines;

an opposing substrate provided with a counter electrode opposite to the array substrate;

liquid crystal filled between the array substrate and the opposing substrate and having different alignment states in a display state and in a non-display state, the liquid crystal being subjected to initialization from the alignment state in the non-display state to the alignment state in the display state before an image is displayed; and

drive means for performing the initialization by inputting voltages with different polarities to two pixel electrodes adjacent in right and left direction, respectively.

13. The liquid crystal display according to claim 12, wherein the drive means is adapted to apply voltages with different polarities to two pixel electrodes adjacent in front and back direction, respectively.

14. The liquid crystal display according to claim 12, wherein the drive means is adapted to apply voltages with the same polarity to two pixel electrodes adjacent in front and back direction, respectively.

15. The liquid crystal display according to claim 12, wherein the drive means is adapted to apply a constant voltage to the counter electrode while applying the voltages to the pixel electrodes.

16. The liquid crystal display according to claim 15, wherein the drive means is adapted to start applying the constant voltage to the counter electrode after start of application of the voltages to the pixel electrodes.

17. The liquid crystal display according to claim 16, wherein the drive means is adapted to start applying the constant voltage to the counter electrode before an elapse of 50 milliseconds after start of application of the voltages to the pixel electrodes.

18. The liquid crystal display according to claim 12, wherein, in two pixel electrodes adjacent in right and left direction, a pixel electrode located on left side is provided with a third protrusion at a right side edge thereof and a pixel electrode located on right side is provided with a fourth protrusion at a left side edge thereof.

19. The liquid crystal display according to claim 18, wherein a tip end of the third protrusion is located closer to right side than a tip end of the fourth protrusion.

20. The liquid crystal display according to claim 18, wherein two third protrusions are provided and the fourth protrusion is located between the two third protrusions.

21. The liquid crystal display according to claim 18, wherein a plurality of third protrusions and a plurality of fourth protrusions are provided and one of the fourth protrusions is interposed between adjacent two third protrusions.

22. The liquid crystal display according to claim 12, wherein the liquid crystal is OCB-mode liquid crystal.

23. A method for driving a liquid crystal display comprising:

an array substrate including a plurality of pixel electrodes arranged in front and back direction and in right and left direction and disposed in matrix;

a plurality of source lines and a plurality of gate lines arranged so as to cross each other; and

switching devices provided as corresponding to the respective pixel electrodes and having gate electrodes connected to the gate lines, source electrodes connected to the source lines, and drain electrodes connected to the pixel electrodes, for switching between the source electrodes and the drain electrodes in accordance with a drive signal input to the gate electrodes through the gate lines;

an opposing substrate provided with a counter electrode opposite to the array substrate; and

liquid crystal filled between the array substrate and the opposing substrate and having different alignment states in a display state and in a non-display state, the liquid crystal being subjected to initialization from the alignment state in the non-display state to the alignment state in the display state before an image is displayed,

wherein the initialization is performed by inputting voltages with different polarities to two pixel electrodes adjacent in front and back direction, respectively.

24. A method for driving a liquid crystal display comprising:

an array substrate including a plurality of pixel electrodes arranged in front and back direction and in right and left direction and disposed in matrix;

a plurality of source lines and a plurality of gate lines arranged so as to cross each other; and

switching devices provided as corresponding to the respective pixel electrodes and having gate electrodes connected to the gate lines, source electrodes connected to the source lines, and drain electrodes connected to the pixel electrodes, for switching between the source electrodes and the drain electrodes in accordance with a drive signal input to the gate electrodes through the gate lines;

an opposing substrate provided with a counter electrode opposite to the array substrate; and

liquid crystal filled between the array substrate and the opposing substrate and having different alignment states in a display state and in a non-display state, the liquid crystal being subjected to initialization from alignment state in the non-display state to the alignment state in the display state before an image is displayed,

wherein the initialization is performed by inputting voltages with different polarities to two pixel electrodes adjacent in right and left direction, respectively.