Liquid crystal display device and manufacturing method thereof

• US 8,605,240 B2
• Filed: 05/09/2011
• Issued: 12/10/2013
• Est. Priority Date: 05/20/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Aihara, Yamato, Jintyou, Masami, Sato, Rai, Arakawa, Toru
• Primary Examiner(s): Briggs, Nathanael R
• Application Number:
  US13/103,147
• Publication Number:
  US 20110285945A1
• Time in Patent Office: 946 Days
• Field of Search: 349/113, 349/114, 349/138
• US Class Current: 349/113
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/13725 based on guest-host interaction G02F1/13762, G02F1/13737, take precedence
• CPC Class Codes: H01L 27/1262 with a particular formation, treatment or coating of the substrate

Abstract

In the liquid crystal display device in which a guest-host liquid crystal layer is provided between a first substrate having a reflective film which is a pixel electrode layer (also referred to as a first electrode layer) and a second substrate having a common electrode layer (also referred to as a second electrode layer), the reflective film which is a pixel electrode layer is projected into the liquid crystal layer, and a micron-sized first unevenness and a nano-sized second unevenness on the first unevenness are provided.

Claims

1. A liquid crystal display device comprising:

a first substrate;

an insulating layer over the first substrate, the insulating layer comprising a first unevenness and a second unevenness;

a reflective pixel electrode layer over a face of the insulating layer, the reflective pixel electrode layer including a third unevenness formed in accordance with the first unevenness and the second unevenness;

a light-transmitting electrode over the reflective pixel electrode layer; and

a second substrate over the light-transmitting electrode,

wherein a contact hole is formed in a part of the insulating layer,

wherein the part of the insulating layer comprises a fourth unevenness,

wherein a guest-host liquid crystal is interposed between the first substrate and the second substrate,

wherein a whole size of the first unevenness is greater than that of the second unevenness, and

wherein each of the second unevenness and the fourth unevenness is provided in higher density than the first unevenness.

2. The liquid crystal display device according to claim 1, wherein the insulating layer comprises a photosensitive organic resin.

3. The liquid crystal display device according to claim 1, wherein the first unevenness has a size of greater than or equal to 1.5 μ

m and less than or equal to 20 μ

m in a planar direction, and

wherein the second unevenness has a size of greater than or equal to 0.1 μ

m and less than or equal to 1 μ

m in the planar direction.

4. The liquid crystal display device according to claim 1, wherein the first unevenness has a height of greater than or equal to 0.1 μ

nm and less than or equal to 20 μ

m, and

wherein the second unevenness has a height of greater than or equal to 0.1 μ

m and less than or equal to 1 μ

m.

5. The liquid crystal display device according to claim 1, wherein the reflective pixel electrode layer has a thickness of greater than or equal to 5 nm and less than or equal to 500 nm.

6. The liquid crystal display device according to claim 1, wherein a guest of the guest-host liquid crystal is a dichroic pigment as a guest molecule and a host of the guest-host liquid crystal is a nematic liquid crystal.

7. The liquid crystal display device according to claim 1, further comprising a transistor between the first substrate and the reflective pixel electrode layer;

and

wherein the reflective pixel electrode layer is electrically connected to the transistor.

8. The liquid crystal display device according to claim 7, wherein the transistor comprises an oxide semiconductor layer.

9. A liquid crystal display device comprising:

a first substrate;

an insulating layer over the first substrate, the insulating layer comprising a first unevenness and a second unevenness;

a reflective pixel electrode layer over a face of the insulating layer, the reflective pixel electrode layer including a third unevenness formed in accordance with the first unevenness and the second unevenness;

a light-transmitting electrode over the reflective pixel electrode layer; and

a second substrate over the light-transmitting electrode,

wherein a contact hole is formed in a part of the insulating layer,

wherein the part of the insulating layer comprises a fourth unevenness,

wherein a guest-host liquid crystal is interposed between the first substrate and the second substrate,

wherein the second unevenness is provided on a face of the first unevenness, and

wherein each of the second unevenness and the fourth unevenness is provided in higher density than the first unevenness.

10. The liquid crystal display device according to claim 9, wherein the insulating layer comprises a photosensitive organic resin.

11. The liquid crystal display device according to claim 9, wherein the first unevenness has a size of greater than or equal to 1.5 μ

m and less than or equal to 20 μ

m in a planar direction, and

wherein the second unevenness has a size of greater than or equal to 0.1 μ

m and less than or equal to 1 μ

m in the planar direction.

12. The liquid crystal display device according to claim 9, wherein the first unevenness has a height of greater than or equal to 0.1 μ

m and less than or equal to 20 μ

m, and

wherein the second unevenness has a height of greater than or equal to 0.1 μ

m and less than or equal to 1 μ

m.

13. The liquid crystal display device according to claim 9, wherein the reflective pixel electrode layer has a thickness of greater than or equal to 5 nm and less than or equal to 500 nm.

14. The liquid crystal display device according to claim 9, wherein a guest of the guest-host liquid crystal is a dichroic pigment as a guest molecule and a host of the guest-host liquid crystal is a nematic liquid crystal.

15. The liquid crystal display device according to claim 9, further comprising a transistor between the first substrate and the reflective pixel electrode layer;

and

wherein the reflective pixel electrode layer is electrically connected to the transistor.

16. The liquid crystal display device according to claim 15, wherein the transistor comprises an oxide semiconductor layer.