LIQUID CRYSTAL DISPLAY AND METHOD FOR MANUFACTURING THE SAME

• US 20070268440A1
• Filed: 05/14/2007
• Published: 11/22/2007
• Est. Priority Date: 05/22/2006
• Status: Active Grant

• Current Assignee: Trivale Technologies, LLC (Vector Capital Corporation)
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Nagano, Shingo
• Granted Patent: US 7,525,626 B2
• Time in Patent Office: Days
• US Class Current: 349/141
• CPC Class Codes: G02F 1/133753 with different alignment orientations or pretilt angles on a same surface, e.g. for grey scale or improved viewing angle
• 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 2201/124 interdigital
• CPC Class Codes: G02F 2203/09 transflective

Abstract

A liquid crystal display includes a liquid crystal layer held between an array substrate and an opposing substrate that are placed opposed to each other and a reflector and a transparent regions in one pixel. The array substrate includes a reflective common electrode provided in the reflector region, a reflective common electrode provided in the reflector region for generating an oblique electric field between the reflective pixel electrode, a transparent common electrode provided in the transparent region and a transparent pixel electrode provided in the transparent region for generating a horizontal electric field between the transparent common electrode.

Claims

1. A liquid crystal display comprising:

a liquid crystal layer held between a first and a second substrate, the first and the second substrate being placed opposite to each other; and

a reflector region and a transparent region in one pixel,

wherein the first substrate comprises;

a comb-like transparent common electrode provided in the transparent region;

a comb-like transparent pixel electrode placed opposed in parallel to the transparent common electrode and for generating a horizontal direction electric field between the transparent common electrode in the transparent region;

a reflective common electrode provided in the reflector region; and

a reflective pixel electrode provided in the reflector region and placed opposed to the reflective common electrode with an insulating film interposed therebetween,

wherein between the reflective common electrode and the reflective pixel electrode, a slit is formed in the electrode provided to an upper layer, and

an oblique electric field is generated between the reflective common electrode and reflective pixel electrode by the slit.

2. The liquid crystal display according to claim 1, wherein

the reflective common electrode is formed in an upper layer of the reflective pixel electrode, and

an angle to a rubbing direction toward a direction the slit of the reflective common electrode is provided and an angle to the rubbing direction toward a direction a comb of the comb-like transparent pixel electrode is provided are different.

3. The liquid crystal display according to claim 1, wherein the reflective common electrode is formed by a transparent conductive film,

the reflective pixel electrode is placed in a lower layer of the reflective common electrode with the insulating film interposed therebetween, and

a surface of the reflective pixel electrode is formed by a metallic film.

4. The liquid crystal display according to claim 1, wherein the reflective pixel electrode is extended from an electrode of a switching device provided to the pixel.

5. The liquid crystal display according to claim 4, wherein the transparent pixel electrode is connected to the switching device via the reflective pixel electrode.

6. The liquid crystal display according to claim 1, wherein the transparent common electrode and the reflective common electrode are formed by a same material.

7. The liquid crystal display according to claim 6, wherein the transparent common electrode and the reflective common electrode are formed by a same transparent conductive film.

8. The liquid crystal display according to claim 6, wherein the transparent pixel electrode is formed by the same material as the transparent common electrode and reflective common electrode.

9. The liquid crystal display according to claim 1, wherein the transparent common electrode and the reflective common electrode are connected to an auxiliary capacity electrode via a contact hole provided in the pixel.

10. The liquid crystal display according to claim 1, wherein

in the reflector region, the reflective common electrode is extended to overlap lines provided to both sides of the pixel with the insulating film interposed therebetween.

11. The liquid crystal display according to claim 1, wherein

in the transparent region, the transparent common electrode is extended to overlap lines provided to both sides of the pixel with the insulating film interposed therebetween.

12. The liquid crystal display according to claim 1, wherein the reflective pixel electrode is a laminated structure having at least an upper and a lower layers, and

in a contact hole for connecting the reflective pixel electrode and the transparent pixel electrode, the upper layer of the reflective pixel electrode is removed and the lower layer is exposed.

13. The liquid crystal display according to claim 1, wherein either or both of the reflector and transparent region is multi-domained.

14. The liquid crystal display according to claim 1, wherein a convexo-concave shape is formed at a foundation film of the reflective pixel electrode.

15. The liquid crystal display according to claim 14, wherein the convexo-concave shape is formed of a semiconductor or a metallic film.

16. A method of manufacturing a liquid crystal display having a liquid crystal layer held between a first and a second substrate disposed opposite to each other, a reflector and transparent regions in one pixel, the method comprising:

forming a first line with a first conductive film provided over the first substrate;

forming a first insulating film and a semiconductor film over the first line;

forming a reflective pixel electrode and a second line with a second conductive film provided over the first insulating film and the semiconductor film, the second line being orthogonal to the first line with the first insulating film interposed therebetween, the reflective pixel electrode having a slit in the reflector region;

forming a second insulating film over the second line and the second reflective pixel electrode; and

forming a comb-like transparent common electrode provided in the transparent region and a reflective common electrode provided in the reflector region by a third conductive film over the second insulating film,

wherein in the transparent region, the transparent common electrode is patterned so that a comb-like transparent pixel electrode formed by the second or the third conductive film is placed opposed parallel to the transparent common electrode and an horizontal electric field is generated between the transparent pixel electrode and the transparent common electrode, and

in the reflector region, the reflective common electrode is patterned so that an oblique electric field is generated between the reflective pixel electrode and the reflective common electrode by the slit provided in the reflective pixel electrode.

17. The method according to claim 16, wherein

the transparent pixel electrode is formed by the third conductive film,

in the formation of the second insulating film, a contact hole to the transparent pixel electrode is formed in the pixel, and

the transparent pixel electrode and reflective pixel electrode is connected via the contact hole.

18. The method according to claim 16, wherein the patterning is made so that a direction of a comb of the comb-like transparent pixel electrode and a direction of the slit of the reflective pixel electrode are different.