Liquid crystal display device and driving method for liquid crystal display device

• US 20030222840A1
• Filed: 04/14/2003
• Published: 12/04/2003
• Est. Priority Date: 04/15/2002
• Status: Active Grant

• Current Assignee: Vista Peak Ventures LLC (Dominion Harbor Enterprises, LLC)
• Original Assignee: NEC LCD Technologies Limited (Tianma Microelectronics Company Limited)
• Inventors: Koga, Koichi, Okuzono, Noboru, Yamaguchi, Machihiko
• Granted Patent: US 7,116,297 B2
• Time in Patent Office: Days
• US Class Current: 345/89
• CPC Class Codes: G09G 3/2074 using sub-pixels
• 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 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers

Abstract

In a liquid crystal display device where each unit pixel p arranged on a liquid crystal panel 101A is constituted by a plurality of pixels p1, p2, and p3, the pixels p1, p2, and p3 are divided into sub-pixels p11 and p12, sub-pixels p21, and p22, and sub-pixels p31 and p32, respectively. The liquid crystal display device is provided with driver ICs 201 and 202 for driving the sub-pixels p11, p21, and p31, and the sub-pixels p12, p22, and p32 constituting the pixels so that different gradation-brightness value characteristics may be given. Due to this, multi-gradation display can be performed.

Claims

1. A liquid crystal display device comprising:

a liquid crystal panel having substrates sandwiching a liquid crystal layer therebetween;

a plurality of unit pixels disposed on said one of said substrates;

a plurality of pixels formed in said unit pixels;

a plurality of sub-pixels formed in said pixels; and

a driving device which drives said sub-pixels so that said sub-pixels have different gradation-brightness value characteristics from each other.

2. The liquid crystal display device according to claim 1, wherein said sub-pixels have different areas from each other;

and

said driving device applies a gradation-brightness value characteristic of a wider brightness value range to said sub-pixels having a larger area than others.

3. The liquid crystal display device according to claim 2, wherein said driving device applies a gradation-brightness value characteristic of a narrower brightness value range to said sub-pixels having a smaller area than said larger area, and said gradation-brightness value characteristic of said narrower brightness value range complementing each one gradation of said gradation-brightness value characteristic of said wider brightness value range.

4. The liquid crystal display device according to claim 3, wherein said gradation-brightness value characteristic of said wider brightness value range is determined by upper bits of a gradation voltage setting input which is input to said driving device, and

said gradation-brightness value characteristic of said narrower brightness value range is determined by lower bits of said gradation voltage setting input.

5. The liquid crystal display device according to claim 1, wherein said sub-pixels have almost equal areas to each other;

said driving device gives one of said sub-pixels a dynamic range corresponding to an upper half of a voltage-brightness value characteristic based on a driving input, and

said driving device gives another one of said sub-pixels a dynamic range corresponding to a lower half of said voltage-brightness value characteristic based on said driving input.

6. The liquid crystal display device according to claim 5, wherein said voltage-brightness value characteristic corresponding to said upper half and said voltage-brightness value characteristic corresponding to said lower half are determined by gradation voltage setting inputs having a same number of bits.

7. The liquid crystal display device according to claim 6, wherein said gradation voltage setting inputs are obtained by applying a frame rate control to original gradation voltage setting inputs.

8. The liquid crystal display device according to claim 1, wherein said driving device includes a plurality of drivers which generate an output for driving sub-pixels in a substantially same positional relation with respect to pixels to which these sub-pixels belong respectively, so that these sub-pixels have a substantially same gradation-brightness value characteristic.

9. The liquid crystal display device according to claim 1, wherein said driving device includes a single driver generating a plurality of outputs for driving sub-pixels in a substantially same positional relation, so that said sub-pixels have a substantially same gradation-brightness value characteristic.

10. The liquid crystal display device according to claim 1, wherein said liquid crystal display panel is for displaying a color image.

11. A liquid crystal display device comprising:

a pair of substrates;

a liquid crystal layer disposed between said pair of substrates;

a plurality of gate lines disposed on one of said pair of substrates;

a plurality of drain lines disposed on one of said pair of substrates and overlapped with said plurality of gate lines;

unit pixels formed in a matrix shape of said plurality of gate lines and said plurality of drain lines;

wherein said unit pixels having a plurality of pixels, and said plurality of pixels further having a plurality of sub-pixels;

a driving device applying a voltage to said plurality of sub-pixels;

wherein said driving device including a plurality of drivers which generate outputs for said sub-pixels connected to a same gate line but to different drain lines which are adjacent; and

said sub-pixels having different gradation-brightness value characteristics from each other.

12. The liquid crystal display device according to claim 11, wherein said sub-pixels have different areas from each other;

and

said driving device applies a gradation-brightness value characteristic of a wider brightness value range to said sub-pixels having a larger area than others.

13. The liquid crystal display device according to claim 12, wherein said driving device applies a gradation-brightness value characteristic of a narrower brightness value range to said sub-pixels having a smaller area than said larger area, and said gradation-brightness value characteristic of said narrower brightness value range complementing each one gradation of said gradation-brightness value characteristic of said wider brightness value range.

14. The liquid crystal display device according to claim 13, wherein said gradation-brightness value characteristic of said wider brightness value range is determined by upper bits of a gradation voltage setting input which is input to said driving device, and

said gradation-brightness value characteristic of said narrower brightness value range is determined by lower bits of said gradation voltage setting input.

15. The liquid crystal display device according to claim 11, wherein said sub-pixels have almost equal areas to each other;

said driving device gives one of said sub-pixels a dynamic range corresponding to an upper half of a voltage-brightness value characteristic based on a driving input, and

said driving device gives another one of said sub-pixels a dynamic range corresponding to a lower half of said voltage-brightness value characteristic based on said driving input.

16. The liquid crystal display device according to claim 15, wherein said voltage-brightness value characteristic corresponding to said upper half and said voltage-brightness value characteristic corresponding to said lower half are determined by gradation voltage setting inputs having a same number of bits.

17. A method of driving a liquid crystal display device where a plurality of pixels constituting each unit pixel and each of said plurality of pixels divided into a first and a second sub-pixels, said method comprising:

a step of supplying a first driver with a voltage changeable within a range of a predetermined voltage V2 to a predetermined voltage V1, as an input value of a gradation voltage for driving the first sub-pixel;

a step of supplying a second driver with a voltage changeable within a range of a predetermined voltage V3 and said predetermined voltage V1, as an input value of a gradation voltage for driving said second sub-pixel, and

a relationship among said voltages V3, V2, and V1 represented by V2>

V3>

V1.

18. The method of driving said liquid crystal display device according to claim 17, wherein said predetermined voltage V2 is a maximum value of a drive voltage to be applied to said first sub-pixel, and said predetermined voltage V1 is a minimum value of a drive voltage to be applied to said first sub-pixel.

19. The method of driving said liquid crystal display device according to claim 17, wherein said predetermined voltage V3 is a maximum value of a drive voltage to be applied to said second sub-pixel.

20. The method of driving the liquid crystal display device according to claim 17, wherein said plurality of pixels are for displaying a color image.