Liquid crystal display device

• US 8,184,253 B2
• Filed: 05/20/2010
• Issued: 05/22/2012
• Est. Priority Date: 05/29/2009
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kubota, Daisuke, Ishitani, Tetsuji, Fukai, Shuji
• Primary Examiner(s): Dudek, James
• Application Number:
  US12/783,764
• Publication Number:
  US 20100328565A1
• Time in Patent Office: 733 Days
• Field of Search: 349/141
• US Class Current: 349/141
• 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 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/13793 Blue phases

Abstract

An object is to provide a liquid crystal display device using a liquid crystal material exhibiting a blue phase, in order to enable a higher contrast. In a liquid crystal display device which includes a liquid crystal layer exhibiting a blue phase, a first structure body and a second structure body are provided over a first electrode layer (a pixel electrode layer) and a second electrode layer (a common electrode layer), respectively. The first structure body and the second structure body are insulators each having a higher dielectric constant than a liquid crystal material used for the liquid crystal layer, and are provided to project into the liquid crystal layer.

Claims

1. A liquid crystal display device comprising:

a first substrate and a second substrate opposed to each other;

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

a pixel electrode layer and a common electrode layer which are provided between the first substrate and the liquid crystal layer;

a first structure body which is provided over the pixel electrode layer and projects into the liquid crystal layer; and

a second structure body which is provided over the common electrode layer and projects into the liquid crystal layer,

wherein liquid crystal molecules in the liquid crystal layer are controlled in a direction parallel to the first substrate and the second substrate, and

wherein a dielectric constant of the first structure body and a dielectric constant of the second structure body are higher than a dielectric constant of the liquid crystal layer.

2. The liquid crystal display device according to claim 1, wherein a dielectric constant of the first structure body and a dielectric constant of the second structure body are 12 or more.

3. The liquid crystal display device according to claim 1, wherein the first structure body and the second structure body each have a stacked-layer structure.

4. The liquid crystal display device according to claim 1, wherein the pixel electrode layer and the common electrode layer each have a comb-like shape.

5. The liquid crystal display device according to claim 1, wherein the liquid crystal layer includes a chiral agent.

6. The liquid crystal display device according to claim 1, wherein the liquid crystal layer includes a photocurable resin and a photopolymerization initiator.

7. The liquid crystal display device according to claim 1, wherein the first structure body and the second structure body include any one of an acrylic resin, an epoxy resin, an amine resin and a pullulan derivative.

8. The liquid crystal display device according to claim 1, wherein a thin film transistor is provided between the first substrate and the pixel electrode layer and between the first substrate the common electrode layer, and

wherein the pixel electrode layer is electrically connected to the thin film transistor.

9. The liquid crystal display device according to claim 8, wherein a light-transmitting chromatic-color resin layer is provided between the thin film transistor and the pixel electrode layer and between the thin film transistor and the common electrode layer.

10. A liquid crystal display device comprising:

a first substrate and a second substrate opposed to each other;

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

a pixel electrode layer and a common electrode layer which are provided between the first substrate and the liquid crystal layer;

a first structure body which is provided over the pixel electrode layer, projects into the liquid crystal layer, and is in contact with the second substrate; and

a second structure body which is provided over the common electrode layer, projects into the liquid crystal layer, and is in contact with the second substrate,

wherein liquid crystal molecules in the liquid crystal layer are controlled in a direction parallel to the first substrate and the second substrate, and

wherein a dielectric constant of the first structure body and a dielectric constant of the second structure body are higher than a dielectric constant of the liquid crystal layer.

11. The liquid crystal display device according to claim 10, wherein a dielectric constant of the first structure body and a dielectric constant of the second structure body are 12 or more.

12. The liquid crystal display device according to claim 10, wherein the first structure body and the second structure body each have a stacked-layer structure.

13. The liquid crystal display device according to claim 10, wherein the pixel electrode layer and the common electrode layer each have a comb-like shape.

14. The liquid crystal display device according to claim 10, wherein the liquid crystal layer includes a chiral agent.

15. The liquid crystal display device according to claim 10, wherein the liquid crystal layer includes a photocurable resin and a photopolymerization initiator.

16. The liquid crystal display device according to claim 10, wherein the first structure body and the second structure body include any one of an acrylic resin, an epoxy resin, an amine resin and a pullulan derivative.

17. The liquid crystal display device according to claim 10, wherein a thin film transistor is provided between the first substrate and the pixel electrode layer and between the first substrate and the common electrode layer, and

wherein the pixel electrode layer is electrically connected to the thin film transistor.

18. The liquid crystal display device according to claim 17, wherein a light-transmitting chromatic-color resin layer is provided between the thin film transistor and the pixel electrode layer and between the thin film transistor and the common electrode layer.

19. A liquid crystal display device comprising:

a first substrate and a second substrate opposed to each other;

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

a pixel electrode layer and a common electrode layer which are provided between the first substrate and the liquid crystal layer;

a first structure body which is provided over the pixel electrode layer and projects into the liquid crystal layer;

a second structure body which is provided over the common electrode layer and projects into the liquid crystal layer; and

a third structure body formed using the same material as the first structure body and the second structure body and provided between the pixel electrode layer and the common electrode layer,

wherein liquid crystal molecules in the liquid crystal layer are controlled in a direction parallel to the first substrate and the second substrate, and

wherein a dielectric constant of the first structure body, a dielectric constant of the second structure body and a dielectric constant of the third structure body are higher than a dielectric constant of the liquid crystal layer.

20. The liquid crystal display device according to claim 19, wherein a dielectric constant of the first structure body, a dielectric constant of the second structure body and a dielectric constant of the third structure body are 12 or more.

21. The liquid crystal display device according to claim 19, wherein the first structure body, the second structure body and the third structure body each have a stacked-layer structure.

22. The liquid crystal display device according to claim 19, wherein the pixel electrode layer and the common electrode layer each have a comb-like shape.

23. The liquid crystal display device according to claim 19, wherein the liquid crystal layer includes a chiral agent.

24. The liquid crystal display device according to claim 19, wherein the liquid crystal layer includes a photocurable resin and a photopolymerization initiator.

25. The liquid crystal display device according to claim 19, wherein the first structure body, the second structure body and the third structure body include any one of an acrylic resin, an epoxy resin, an amine resin and a pullulan derivative.

26. The liquid crystal display device according to claim 19, wherein a thin film transistor is provided between the first substrate and the pixel electrode layer and between the first substrate and the common electrode layer, and

wherein the pixel electrode layer is electrically connected to the thin film transistor.

27. The liquid crystal display device according to claim 26, wherein a light-transmitting chromatic-color resin layer is provided between the thin film transistor and the pixel electrode layer and between the thin film transistor and the common electrode layer.