Liquid crystal display device

• US 20080218666A1
• Filed: 03/05/2008
• Published: 09/11/2008
• Est. Priority Date: 03/08/2007
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: Toyooka, Kentarou
• Granted Patent: US 7,847,888 B2
• Time in Patent Office: Days
• US Class Current: 349/96
• CPC Class Codes: G02F 1/133311 Environmental protection, e.g. against dust or humidity
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 2201/50 Protective arrangements
• CPC Class Codes: G02F 2202/28 Adhesive materials or arrangements

Abstract

The present invention provides a liquid crystal display device containing: a liquid crystal cell; a backlight; a first polarizing plate disposed between the liquid crystal cell and the backlight and having a polarizer and at least two protective films disposed so as to sandwich the polarizer; and a second polarizing plate disposed on a side of the liquid crystal cell opposite to a side on which the first polarizing plate is provided and having a polarizer and at least two protective films disposed so as to sandwich the polarizer, wherein a moisture permeability of the protective films on both sides of the first polarizing plate at 60° C. and 95% RH is more than 300 g/m² day, and a moisture permeability of at least one protective film of the second polarizing plate at 60° C. and 95% RH is equal to or less than 300 g/m²·day.

Claims

1. A liquid crystal display device, comprising:

a liquid crystal cell;

a backlight;

a first polarizing plate disposed between the liquid crystal cell and the backlight and having a polarizer and at least two protective films disposed so as to sandwich the polarizer; and

a second polarizing plate disposed on a side of the liquid crystal cell opposite to a side on which the first polarizing plate is provided and having a polarizer and at least two protective films disposed so as to sandwich the polarizer,

wherein a moisture permeability of the protective films on both sides of the first polarizing plate at a temperature of 60°

C. and a relative humidity of 95% is more than 300 g/m²·

day, and a moisture permeability of at least one protective film of the second polarizing plate at a temperature of 60°

C. and a relative humidity of 95% is equal to or less than 300 g/m²·

day.

2. The liquid crystal display device according to claim 1, wherein a brightness enhancement film is provided between the polarizer of the first polarizing plate and the backlight.

3. The liquid crystal display device according to claim 2, wherein the protective film disposed between the polarizer of the first polarizing plate and the backlight is the brightness enhancement film.

4. The liquid crystal display device according to claim 1, wherein the protective film disposed between the polarizer of the first polarizing plate and the backlight has an in-plane retardation (Re) of 10 nm or less at a wavelength of 630 nm, and a thickness-direction retardation (Rth) of 60 nm or less at a wavelength of 630 nm.

5. The liquid crystal display device according to claim 1, wherein the protective film disposed between the polarizer of the first polarizing plate and the backlight satisfies the following Formulas (I) to (IV):

0≦

Re₍₆₃₀₎≦

10  

 

Formula (I)

|Rth₍₆₃₀₎|≦

25  

 

Formula (II)

|Re₍₄₀₀₎−

Re₍₇₀₀₎|≦

10  

 

Formula (III)

|Rth₍₄₀₀₎−

Rth₍₇₀₀₎|≦

35  

 

Formula (IV)

in Formulas (I) to (IV) above, Re<sub>(λ

)</sub> is a front retardation value (nm) at a wavelength λ

(nm), and Rth<sub>(λ

)</sub> is a thickness-direction retardation value (nm) at a wavelength λ

(nm).

6. The liquid crystal display device according to claim 1, wherein the first polarizing plate is provided with at least one of a hard coat layer having hard coat ability and an antireflection layer.