Liquid crystal display device

• US 8,395,718 B2
• Filed: 02/17/2012
• Issued: 03/12/2013
• Est. Priority Date: 05/17/2007
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kimura, Hajime
• Primary Examiner(s): DUONG, THOI V
• Application Number:
  US13/399,147
• Publication Number:
  US 20120212686A1
• Time in Patent Office: 389 Days
• Field of Search: 349/43, 349/38, 349/48, 349/39, 349/143, 349/139, 349/144, 349/41, 349/42
• US Class Current: 349/48
• CPC Class Codes: G02F 1/134345 Subdivided pixels, e.g. for grey scale or redundancy
• CPC Class Codes: G02F 1/134354 the sub-pixels being capacitively coupled
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 1/13624 having more than one switching element per pixel
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 2201/121 common or background
• CPC Class Codes: G02F 2201/123 pixel
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2300/0486 Cholesteric liquid crystals, including chiral-nematic liquid crystals, with transitions between focal conic, planar, and homeotropic states
• CPC Class Codes: G09G 2300/0814 used for selection purposes, e.g. logical AND for partial update
• CPC Class Codes: G09G 2300/0885 Pixel comprising a non-linear two-terminal element alone in series with each display pixel element
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2320/068 for control of viewing angle adjustment
• CPC Class Codes: G09G 2320/106 Determination of movement vectors or equivalent parameters within the image
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2340/0435 : Change or adaptation of the frame rate of the video stream
• CPC Class Codes: G09G 2360/145 : the light originating from the display screen
• CPC Class Codes: G09G 3/2074 : using sub-pixels
• CPC Class Codes: G09G 3/342 : using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• 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
• CPC Class Codes: G09G 3/3677 : suitable for active matrices only
• CPC Class Codes: H01L 27/1225 : with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 27/124 : with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 29/22 : including, apart from doping materials or other impurities, only AIIBVI compounds
• CPC Class Codes: H01L 29/24 : including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• CPC Class Codes: H01L 29/42356 : Disposition, e.g. buried gate electrode H01L29/42324 and H01L29/4234 take precedence
• CPC Class Codes: H01L 29/78651 : Silicon transistors H01L29/78606 - H01L29/78645 take precedence
• CPC Class Codes: H01L 29/7869 : having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H01L 29/78696 : characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/0041 : characterised by field-effect operation

Abstract

It is an object to provide a liquid crystal display device which has excellent viewing angle characteristics and higher quality. The present invention has a pixel including a first switch, a second switch, a third switch, a first resistor, a second resistor, a first liquid crystal element, and a second liquid crystal element. A pixel electrode of the first liquid crystal element is electrically connected to a signal line through the first switch. The pixel electrode of the first liquid crystal element is electrically connected to a pixel electrode of the second liquid crystal element through the second switch and the first resistor. The pixel electrode of the second liquid crystal element is electrically connected to a Cs line through the third switch and the second resistor. A common electrode of the first liquid crystal element is electrically connected to a common electrode of the second liquid crystal element.

Claims

1. A display device comprising a first sub-pixel and a second sub-pixel, the display device comprising:

a first line;

a second line crossing the first line;

a third line extending in parallel with the first line;

a first switch wherein the first line is electrically connected to the first switch;

a first pixel electrode of the first sub-pixel, wherein the first pixel electrode is electrically connectable to the second line through the first switch;

a first capacitor wherein a first electrode of the first capacitor is electrically connected to the first pixel electrode;

a second switch wherein the first line is electrically connected to the second switch;

a second pixel electrode of the second sub-pixel, wherein the second pixel electrode is electrically connectable to the second line through the second switch;

a second capacitor wherein a first electrode of the second capacitor is electrically connected to the second pixel electrode;

a transistor wherein one of a source and a drain of the transistor is electrically connected to the second pixel electrode; and

a third capacitor wherein a first electrode of the third capacitor is electrically connected to the other of the source and the drain of the transistor and wherein a second electrode of the third capacitor is electrically connected to the third line,

wherein the first sub-pixel is located on a first side of the first line and the second sub-pixel is located on a second side of the first line, the first side being opposite to the second side.

2. The display device according to claim 1, wherein a gate of the transistor is electrically connected to the first line.

3. The display device according to claim 1, wherein the display device is a liquid crystal device.

4. The display device according to claim 1, further comprising a third pixel electrode,

wherein the third pixel electrode is electrically connected to the other of the source and the drain of the transistor.

5. The display device according to claim 1, further comprising:

a second transistor wherein one of a source and a drain of the second transistor is electrically connected to the first pixel electrode; and

a third pixel electrode wherein the third pixel electrode is electrically connected to the other of the source and the drain of the second transistor.

6. The display device according to claim 1, wherein the transistor includes a channel comprising an oxide semiconductor.

7. A display device comprising a first sub-pixel and a second sub-pixel, the display device comprising:

a first line;

a second line crossing the first line;

a third line extending in parallel with the first line;

a first transistor wherein the first line is electrically connected to a gate of the first transistor;

a first pixel electrode of the first sub-pixel, wherein the first pixel electrode is electrically connectable to the second line through the first transistor;

a first capacitor wherein a first electrode of the first capacitor is electrically connected to the first pixel electrode;

a second transistor wherein the first line is electrically connected to a gate of the second transistor;

a second pixel electrode of the second sub-pixel, wherein the second pixel electrode is electrically connectable to the second line through the second transistor;

a second capacitor wherein a first electrode of the second capacitor is electrically connected to the second pixel electrode;

a third transistor wherein one of a source and a drain of the third transistor is electrically connected to the second pixel electrode; and

a third capacitor wherein a first electrode of the third capacitor is electrically connected to the other of the source and the drain of the third transistor and wherein a second electrode of the third capacitor is electrically connected to the third line,

wherein the first sub-pixel is located on a first side of the first line and the second sub-pixel is located on a second side of the first line, the first side being opposite to the second side.

8. The display device according to claim 7, wherein a gate of the third transistor is electrically connected to the first line.

9. The display device according to claim 7, wherein the display device is a liquid crystal device.

10. The display device according to claim 7, further comprising a third pixel electrode,

wherein the third pixel electrode is electrically connected to the other of the source and the drain of the third transistor.

11. The display device according to claim 7, further comprising:

a fourth transistor wherein one of a source and a drain of the fourth transistor is electrically connected to the first pixel electrode; and

a third pixel electrode wherein the third pixel electrode is electrically connected to the other of the source and the drain of the fourth transistor.

12. The display device according to claim 7, wherein at least one of the first transistor, the second transistor and the third transistor includes a channel comprising an oxide semiconductor.

13. A portable information terminal including a display device which comprises a first sub-pixel and a second sub-pixel, the display device comprising:

a first line;

a second line crossing the first line;

a third line extending in parallel with the first line;

a first switch wherein the first line is electrically connected to the first switch;

a first pixel electrode of the first sub-pixel, wherein the first pixel electrode is electrically connectable to the second line through the first switch;

a first capacitor wherein a first electrode of the first capacitor is electrically connected to the first pixel electrode;

a second switch wherein the first line is electrically connected to the second switch;

a second pixel electrode of the second sub-pixel, wherein the second pixel electrode is electrically connectable to the second line through the second switch;

a second capacitor wherein a first electrode of the second capacitor is electrically connected to the second pixel electrode;

a transistor wherein one of a source and a drain of the transistor is electrically connected to the second pixel electrode; and

a third capacitor wherein a first electrode of the third capacitor is electrically connected to the other of the source and the drain of the transistor and wherein a second electrode of the third capacitor is electrically connected to the third line,

wherein the first sub-pixel is located on a first side of the first line and the second sub-pixel is located on a second side of the first line, the first side being opposite to the second side.

14. The portable information terminal according to claim 13, wherein a gate of the transistor is electrically connected to the first line.

15. The portable information terminal according to claim 13, wherein the portable information terminal is a mobile phone.

16. The portable information terminal according to claim 13, further comprising a third pixel electrode,

wherein the third pixel electrode is electrically connected to the other of the source and the drain of the transistor.

17. The portable information terminal according to claim 13, further comprising:

a second transistor wherein one of a source and a drain of the second transistor is electrically connected to the first pixel electrode; and

a third pixel electrode wherein the third pixel electrode is electrically connected to the other of the source and the drain of the second transistor.

18. The portable information terminal according to claim 13, wherein the transistor includes a channel comprising an oxide semiconductor.

19. A portable information terminal including a display device which comprises a first sub-pixel and a second sub-pixel, the display device comprising:

a first line;

a second line crossing the first line;

a third line extending in parallel with the first line;

a first transistor wherein the first line is electrically connected to a gate of the first transistor;

a first pixel electrode of the first sub-pixel, wherein the first pixel electrode is electrically connectable to the second line through the first transistor;

a first capacitor wherein a first electrode of the first capacitor is electrically connected to the first pixel electrode;

a second transistor wherein the first line is electrically connected to a gate of the second transistor;

a second pixel electrode of the second sub-pixel, wherein the second pixel electrode is electrically connectable to the second line through the second transistor;

a second capacitor wherein a first electrode of the second capacitor is electrically connected to the second pixel electrode;

a third transistor wherein one of a source and a drain of the third transistor is electrically connected to the second pixel electrode; and

a third capacitor wherein a first electrode of the third capacitor is electrically connected to the other of the source and the drain of the third transistor and wherein a second electrode of the third capacitor is electrically connected to the third line,

wherein the first sub-pixel is located on a first side of the first line and the second sub-pixel is located on a second side of the first line, the first side being opposite to the second side.

20. The portable information terminal according to claim 19, wherein a gate of the third transistor is electrically connected to the first line.

21. The portable information terminal according to claim 19, wherein the portable information terminal is a mobile phone.

22. The portable information terminal according to claim 19, further comprising a third pixel electrode,

wherein the third pixel electrode is electrically connected to the other of the source and the drain of the third transistor.

23. The portable information terminal according to claim 19, further comprising:

a fourth transistor wherein one of a source and a drain of the fourth transistor is electrically connected to the first pixel electrode; and

a third pixel electrode wherein the third pixel electrode is electrically connected to the other of the source and the drain of the fourth transistor.

24. The portable information terminal according to claim 19, wherein at least one of the first transistor, the second transistor and the third transistor includes a channel comprising an oxide semiconductor.