Liquid crystal display device

• US 9,625,762 B2
• Filed: 05/18/2015
• Issued: 04/18/2017
• Est. Priority Date: 08/05/2014
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Na, Gwan-Young, Kim, Sang-Jae, Kim, Teck-Soo, Lee, Hyoung-Joo, Cho, Seon-Ah, Kim, Kwang-Hyun, Kim, Ji-Hye
• Primary Examiner(s): Rude, Timothy L
• Application Number:
  US14/714,737
• Publication Number:
  US 20160041426A1
• Time in Patent Office: 701 Days
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation

Abstract

Disclosed is a liquid crystal display device, including: first and second substrates, which are spaced apart from each other by a predetermined interval while facing each other; a reflective polarizing plate disposed under the first substrate, and including a first refractive index layer and a second refractive index layer, which have different refractive indexes and are repeatedly stacked; first and second compensation layers sequentially stacked on the second substrate, and an upper polarizing plate including a polarizing layer formed on the second compensation layer; and a liquid crystal layer formed between the first and second substrates.

Claims

1. A liquid crystal display device, comprising:

a first substrate and a second substrate facing each other at a predetermined interval;

a reflective polarizing plate disposed under the first substrate, and including a first refractive index layer and a second refractive index layer having different refractive indexes and being alternately stacked;

a first compensation layer and a second compensation layer sequentially stacked on the second substrate;

an upper polarizing plate comprising a polarizing layer disposed on the second compensation layer; and

a liquid crystal layer disposed between the first and second substrates,

wherein the reflective polarizing plate comprises a first group layer and second group layer, the first and second group layers respectively comprising a first refractive index layer and a second refractive index layer repeatedly stacked, and

wherein a buffer layer is disposed between the first group layer and the second group layer.

2. The liquid crystal display device of claim 1, wherein the first compensation layer comprises a positive C plate, and the second compensation layer comprises a negative B plate.

3. The liquid crystal display device of claim 2, wherein the first compensation layer is configured to have a phase difference in a thickness direction within a range of −

200 nm to −

40 nm, and

the second compensation layer is configured to have a phase difference value in a thickness direction within a range of 40 nm to 160 nm and a front phase difference value in a range of 40 to 160 nm.

4. The liquid crystal display device of claim 1, wherein the reflective polarizing plate comprises a third group layer, the third group layer comprising the first refractive index layer and the second refractive index layer repeatedly stacked, and

a buffer layer is disposed between the second group layer and the third group layer.

5. The liquid crystal display device of claim 4, wherein a thickness ratio of a first refractive index layer to a second refractive index layer in the third group layer is different from a thickness ratio of a first refractive index layer to a second refractive index layer in the first and second group layers.

6. The liquid crystal display device of claim 5, wherein the first refractive index layer and second refractive index layer in the third group layer have the same thickness.

7. The liquid crystal display device of claim 1, wherein a thickness ratio of a first refractive index layer to a second refractive index layer in the first group layer is the same as a thickness ratio of a first refractive index layer to a second refractive index layer in the second group layer.

8. The liquid crystal display device of claim 1, wherein the first and second compensation layers are configured to compensate for a phase difference value in a thickness direction of the reflective polarizing plate.

9. The liquid crystal display device of claim 8, wherein the first and second compensation layers comprises tri-acetyl cellulose (TAC).

10. The liquid crystal display device of claim 8, wherein the polarizing layer comprises a polarizer (poly-vinyl alcohol:

PVA) disposed on the second compensation layer, and a surface processed passivation layer (tri-acetyl cellulose;

TAC) disposed on the polarizer.

11. The liquid crystal display device of claim 1, wherein the liquid crystal layer comprises in-plane liquid crystal.