LIQUID CRYSTAL DISPLAY DEVICE AND METHOD FOR MANUFACTURING THE SAME

• US 20100302492A1
• Filed: 05/13/2010
• Published: 12/02/2010
• Est. Priority Date: 05/29/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: ISHITANI, Tetsuji, TAMURA, Tomohiro, KUBOTA, Daisuke, YAMASHITA, Akio
• Granted Patent: US 8,654,292 B2
• Time in Patent Office: Days
• US Class Current: 349/138
• CPC Class Codes: G02F 1/133603 with LEDs
• 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 1/1343 Electrodes reflective electrodes G02F1/133553
• 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 1/1345 Conductors connecting electrodes to cell terminals
• CPC Class Codes: G02F 1/13793 Blue phases
• CPC Class Codes: G02F 2202/023 curable
• CPC Class Codes: G02F 2202/103 a-Si
• CPC Class Codes: G02F 2202/104 poly-Si
• CPC Class Codes: G02F 2202/105 single crystal Si
• 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 29/04 characterised by their crystalline structure, e.g. polycrystalline, cubic or particular orientation of crystalline planes characterised by physical imperfections H01L29/30
• 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

Abstract

A liquid crystal display device using a liquid crystal exhibiting a blue phase and having a novel structure, and a method for manufacturing the liquid crystal display device. A plurality of structure bodies (also referred to as ribs, protrusions, or projecting portions) are formed over the same substrate, and a pixel electrode and an electrode (a common electrode at a fixed potential) corresponding to the pixel electrode are formed thereover. An electric field is applied to the liquid crystal layer exhibiting a blue phase by using the pixel electrode that has an inclination and the electrode corresponding to the pixel electrode, which also has an inclination. A shorter distance between the adjacent structure bodies allows a strong electric field to be applied to the liquid crystal layer, which results in a reduction in power consumption for driving the liquid crystal.

Claims

1. A liquid crystal display device comprising:

a first substrate and a second substrate;

a liquid crystal layer containing a liquid crystal material exhibiting a blue phase between the first substrate and the second substrate;

a plurality of structure bodies over the first substrate and between the first substrate and the second substrate;

a first electrode layer over the plurality of structure bodies;

an insulating layer over the first electrode layer; and

a second electrode layer which overlaps the first electrode layer with the insulating layer interposed therebetween,

wherein the plurality of structure bodies are arranged at regular intervals,

wherein an angle between each of side surfaces of the plurality of structure bodies and a plane surface of the first substrate is less than 90°

,

wherein the second electrode layer overlaps at least one of the side surfaces of the plurality of structure bodies with the first electrode layer and the insulating layer interposed therebetween, and

wherein the second electrode layer includes a plurality of openings.

2. The liquid crystal display device according to claim 1, wherein the plurality of structure bodies comprise an organic resin material.

3. The liquid crystal display device according to claim 1, wherein the first electrode layer is at a fixed potential and the second electrode layer is electrically connected to a thin film transistor.

4. The liquid crystal display device according to claim 1, wherein a third electrode layer is formed on the second substrate, the third electrode layer is at a fixed potential, and the third electrode layer overlaps the first electrode layer with the liquid crystal layer interposed therebetween.

5. The liquid crystal display device according to claim 1, wherein the first electrode layer is electrically connected to a thin film transistor and the second electrode layer is at a fixed potential.

6. The liquid crystal display device according to claim 1, wherein a third electrode layer is formed on the second substrate and between the first substrate and the second substrate, the third electrode layer is at a fixed potential, and the third electrode layer overlaps the second electrode layer with the liquid crystal layer interposed therebetween.

7. The liquid crystal display device according to claim 1, wherein the insulating layer comprises an inorganic insulating material.

8. A liquid crystal display device comprising:

a first substrate and a second substrate;

a liquid crystal layer containing a liquid crystal material exhibiting a blue phase between the first substrate and the second substrate;

a first structure body, a second structure body, and a third structure body over the first substrate and between the first substrate and the second substrate;

a first electrode layer over the first structure body, the second structure body, and the third structure body;

an insulating layer over the first electrode layer; and

a second electrode layer which overlaps a side surface of the first structure body and a side surface of the third structure body with the insulating layer interposed therebetween,

wherein the second electrode layer includes an opening,

wherein the first structure body, the second structure body, and the third structure body are arranged at regular intervals,

wherein the second structure body is provided between the first structure body and the third structure body, and

wherein the opening of the second electrode layer overlaps the second structure body.

9. The liquid crystal display device according to claim 8, wherein the first structure body, the second structure body, and the third structure body comprise an organic resin material.

10. The liquid crystal display device according to claim 8, wherein the first electrode layer is at a fixed potential and the second electrode layer is electrically connected to a thin film transistor.

11. The liquid crystal display device according to claim 8, wherein a third electrode layer is formed on the second substrate, the third electrode layer is at a fixed potential, and the third electrode layer overlaps the first electrode layer with the liquid crystal layer interposed therebetween.

12. The liquid crystal display device according to claim 8, wherein the first electrode layer is electrically connected to a thin film transistor and the second electrode layer is at a fixed potential.

13. The liquid crystal display device according to claim 8, wherein a third electrode layer is formed on the second substrate and between the first substrate and the second substrate, the third electrode layer is at a fixed potential, and the third electrode layer overlaps the second electrode layer with the liquid crystal layer interposed therebetween.

14. The liquid crystal display device according to claim 8, wherein the insulating layer comprises an inorganic insulating material.

15. A method for manufacturing a liquid crystal display device comprising the steps of:

forming a gate electrode layer over a first substrate;

forming a plurality of structure bodies over the first substrate;

forming a first electrode layer over the plurality of structure bodies;

forming an insulating layer to cover the gate electrode layer and the first electrode layer;

forming a semiconductor layer over the insulating layer, which overlaps the gate electrode layer;

forming a conductive layer over the semiconductor layer;

forming a second electrode layer over the conductive layer, the second electrode layer being electrically connected to the semiconductor layer; and

fixing a second substrate to the first substrate with a liquid crystal layer interposed therebetween,

wherein the second electrode layer partly overlaps the plurality of structure bodies, the first electrode layer, and the insulating layer.

16. The method for manufacturing a liquid crystal display device according to claim 15, wherein a liquid crystal material exhibiting a blue phase is used for the liquid crystal layer.

17. The method for manufacturing a liquid crystal display device according to claim 15, wherein the liquid crystal layer includes a chiral agent.

18. The method for manufacturing a liquid crystal display device according to claim 15, wherein the liquid crystal layer includes a photocurable resin and a photopolymerization initiator.