Liquid crystal panel and liquid crystal display apparatus

• US 7,639,329 B2
• Filed: 05/01/2008
• Issued: 12/29/2009
• Est. Priority Date: 05/01/2007
• Status: Active Grant

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Takeda, Kentarou, Hayashi, Daisuke, Kitagawa, Takeharu, Murakami, Nao, Nagase, Junichi, Ishida, Hideki
• Primary Examiner(s): Font; Frank G
• Assistant Examiner(s): CHIEM, DINH D
• Application Number:
  US12/113,515
• Publication Number:
  US 20080273153A1
• Time in Patent Office: 607 Days
• Field of Search: 349/117
• US Class Current: 349/117
• CPC Class Codes: G02F 1/133634 the refractive index Nz perpendicular to the element surface being different from in-plane refractive indices Nx and Ny, e.g. biaxial or with normal optical axis
• CPC Class Codes: G02F 1/133635 Multifunctional compensators
• CPC Class Codes: G02F 1/1393 the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells G02F1/1396, G02F1/141 take precedence
• CPC Class Codes: G02F 2413/02 Number of plates being 2

Abstract

The liquid crystal panel according to an embodiment of the present invention includes, in the stated order from a viewer side: a first polarizer; a first optical compensation layer; a liquid crystal cell; a second optical compensation layer; and a second polarizer, wherein:

the first optical compensation layer has an absolute value of a photoelastic coefficient of 40×10⁻¹² (m²/N) or less, has an in-plane retardation Δnd of 90 nm to 200 nm, has relationships of the following Expressions (1) and (2), and functions as a protective layer on a liquid crystal cell side of the first polarizer; and

the second optical compensation layer has relationships of the following Expressions (3) and (4),
Δnd(380)=Δnd(550)=Δnd(780)  (1)
nx>ny>nz  (2)
Rth(380)>Rth(550)>Rth(780)  (3)
nx=ny>nz  (4).

Claims

1. A liquid crystal panel, comprising, in the stated order from a viewer side:

a first polarizer;

a first optical compensation layer;

a liquid crystal cell;

a second optical compensation layer; and

a second polarizer, wherein;

the first optical compensation layer has an absolute value of a photoelastic coefficient of 40×

10<sup>−

12</sup> (m²/N) or less, has an in-plane retardation Δ

nd of 90 nm to 200 nm, has relationships of the following Expressions (1) and (2), and functions as a protective layer on a liquid crystal cell side of the first polarizer; and

the second optical compensation layer has relationships of the following Expressions (3) and (4),

Δ

nd(380)=Δ

nd(550)=Δ

nd(780) 

 

(1)

nx>

ny≧

nz 

 

(2)

Rth(380)>

Rth(550)>

Rth(780) 

 

(3)

nx=ny>

nz 

 

(4).

2. A liquid crystal panel according to claim 1, wherein the first optical compensation layer has a difference between a maximum value and a minimum value of Δ

nd at a wavelength of 380 nm to 780 nm of 10 nm or less.

3. A liquid crystal panel according to claim 1, wherein the first optical compensation layer has an Nz coefficient in a range of 1.1 to 3.0.

4. A liquid crystal panel according to claim 1, wherein the first optical compensation layer has an Nz coefficient of more than 0.9 and less than 1.1.

5. A liquid crystal panel according to claim 1, wherein the first optical compensation layer is a film containing a cyclic olefin-based resin.

6. A liquid crystal panel according to claim 5, wherein the film containing the cyclic olefin-based resin is produced by fixed-end uniaxial stretching.

7. A liquid crystal panel according to claim 1, wherein the second optical compensation layer contains at least one non-liquid crystal material selected from a group consisting of polyamide, polyimide, polyester, polyetherketone, polyamideimide, and polyesterimide.

8. A liquid crystal panel according to claim 1, wherein the first optical compensation layer and the first polarizer are attached to each other with a water-soluble adhesive containing a polyvinyl alcohol-based resin.

9. A liquid crystal panel according to claim 8, wherein the water-soluble adhesive contains a metal compound colloid.

10. A liquid crystal panel according to claim 1, wherein the liquid crystal cell has a drive mode of one of a VA mode and an OCD mode.

11. A liquid crystal display apparatus comprising the liquid crystal panel according to claim 1.