Liquid crystal display device and electronic appliance

• US 20080002079A1
• Filed: 05/30/2007
• Published: 01/03/2008
• Est. Priority Date: 06/02/2006
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kimura, Hajime
• Granted Patent: US 7,847,904 B2
• Time in Patent Office: Days
• US Class Current: 349/42
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02F 1/133371 Cells with varying thickness of the liquid crystal layer
• CPC Class Codes: G02F 1/133502 Antiglare, refractive index matching layers
• CPC Class Codes: G02F 1/133524 Light-guides, e.g. fibre-optic bundles, louvered or jalousie light-guides
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133604 with lamps
• CPC Class Codes: G02F 1/1343 Electrodes reflective electrodes G02F1/133553
• CPC Class Codes: G02F 1/134318 having a patterned common electrode
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/134372 for fringe field switching [FFS] where the common electrode is not patterned
• CPC Class Codes: G02F 1/13454 Drivers integrated on the active matrix substrate G02F1/136277 takes precedence
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: G02F 1/136231 for reducing the number of lithographic steps
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 2201/124 interdigital
• CPC Class Codes: G02F 2201/50 : Protective arrangements
• CPC Class Codes: G09G 2310/024 : Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
• CPC Class Codes: G09G 2320/0252 : Improving the response speed
• CPC Class Codes: G09G 2340/16 : Determination of a pixel data signal depending on the signal applied in the previous frame
• 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 3/3648 : using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: H01L 27/1214 : comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1225 : with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO

Abstract

A pixel electrode or a common electrode is a light-transmissive conductive film; therefore, it is formed of ITO conventionally. Accordingly, the number of manufacturing steps and masks, and manufacturing cost have been increased. An object of the present invention is to provide a semiconductor device, a liquid crystal display device, and an electronic appliance each having a wide viewing angle, less numbers of manufacturing steps and masks, and low manufacturing cost compared with a conventional device. A semiconductor layer of a transistor, a pixel electrode, and a common electrode of a liquid crystal element are formed in the same step.

Claims

1. A liquid crystal display device comprising:

a pixel electrode, a common electrode, and a transistor over a substrate;

an insulating film over the first electrode and the second electrode; and

a liquid crystal over the pixel electrode, the common electrode, and the transistor,

wherein the pixel electrode and the common electrode are formed in the same layer as a semiconductor film of the transistor,

wherein orientation of the liquid crystal is switched by an electric field between the pixel electrode and the common electrode.

2. The liquid crystal display device according to claim 1, wherein the pixel electrode and the common electrode are comb teeth-shaped electrodes.

3. An electronic appliance comprising the liquid crystal display device according to claim 1 for a display portion.

4. A liquid crystal display device comprising:

a first electrode, a second electrode, and a transistor over a substrate;

an insulating film over the first electrode and the second electrode; and

a liquid crystal over the first electrode, the second electrode, and the transistor,

wherein the first electrode and the second electrode are formed in the same layer as a semiconductor film of the transistor.

5. The liquid crystal display device according to claim 4,

wherein the first electrode is a pixel electrode;

and

wherein the second electrode is a common electrode.

6. The liquid crystal display device according to claim 4,

wherein the first electrode is a common electrode;

and

wherein the second electrode is a pixel electrode.

7. The liquid crystal display device according to claim 4,

wherein orientation of the liquid crystal is controlled by an electric field between the first electrode and the second electrode.

8. The liquid crystal display device according to claim 4, wherein the first electrode and the second electrode are comb teeth-shaped electrodes.

9. An electronic appliance comprising the liquid crystal display device according to claim 4 for a display portion.

10. A liquid crystal display device comprising:

a first electrode, a second electrode, and a transistor over a substrate;

an insulating film over the first electrode and the second electrode; and

a liquid crystal over the first electrode, the second electrode, and the transistor,

wherein the first electrode, the second electrode, and the transistor include a semiconductor film containing silicon,

11. The liquid crystal display device according to claim 10,

wherein the first electrode is a pixel electrode;

and

wherein the second electrode is a common electrode.

12. The liquid crystal display device according to claim 10,

wherein the first electrode is a common electrode;

and

wherein the second electrode is a pixel electrode.

13. The liquid crystal display device according to claim 10,

wherein orientation of the liquid crystal is controlled by an electric field between the first electrode and the second electrode.

14. The liquid crystal display device according to claim 10, wherein the first electrode and the second electrode are comb teeth-shaped electrodes.

15. An electronic appliance comprising the liquid crystal display device according to claim 10 for a display portion.

16. A liquid crystal display device comprising:

a first electrode, a second electrode, and a transistor over a substrate;

an insulating film over the first electrode and the second electrode; and

a liquid crystal over the first electrode, the second electrode, and the transistor,

wherein the first electrode, the second electrode, and the transistor include a semiconductor film containing silicon,

wherein the first electrode and the second electrode are formed in the same layer as the semiconductor film of the transistor,

wherein the semiconductor film of the first electrode, the second electrode, and the transistor contain an impurity including the same conductivity type.

17. The liquid crystal display device according to claim 16,

wherein the first electrode is a pixel electrode;

and

wherein the second electrode is a common electrode.

18. The liquid crystal display device according to claim 16,

wherein the first electrode is a common electrode;

and

wherein the second electrode is a pixel electrode.

19. The liquid crystal display device according to claim 16,

wherein orientation of the liquid crystal is controlled by an electric field between the first electrode and the second electrode.

20. The liquid crystal display device according to claim 16, wherein the first electrode and the second electrode are comb teeth-shaped electrodes.

21. An electronic appliance comprising the liquid crystal display device according to claim 16 for a display portion.

22. A liquid crystal display device comprising:

a first insulating film over a substrate;

a first electrode, a second electrode, and a transistor over the first insulating film;

a second insulating film over the first electrode, the second electrode, and a semiconductor film of the transistor;

a gate electrode over the semiconductor film of the transistor; and

a liquid crystal over the first electrode, the second electrode, and the transistor,

wherein the first electrode, the second electrode, and the transistor include a semiconductor film containing silicon,

wherein the first electrode and the second electrode are formed in the same layer as the semiconductor film of the transistor,

wherein the semiconductor film of the first electrode, the second electrode, and the transistor contain an impurity including the same conductivity type.

23. The liquid crystal display device according to claim 22,

wherein the first electrode is a pixel electrode;

and

wherein the second electrode is a common electrode.

24. The liquid crystal display device according to claim 22,

wherein the first electrode is a common electrode;

and

wherein the second electrode is a pixel electrode.

25. The liquid crystal display device according to claim 22,

wherein orientation of the liquid crystal is controlled by an electric field between the first electrode and the second electrode.

26. The liquid crystal display device according to claim 22, wherein the first electrode and the second electrode are comb teeth-shaped electrodes.

27. An electronic appliance comprising the liquid crystal display device according to claim 22 for a display portion.