IP Library Granted Patent US 7,663,720
Granted Patent B2
US 7,663,720 · App. 12/034,739 · Granted Feb 16, 2010

Liquid crystal display device

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Quick Facts
Patent No.
US 7,663,720
App. No.
12/034,739
Filed
Feb 21, 2008
Granted
Feb 16, 2010
Kind
B2
Examiner
HEALY, BRIAN
Art Unit
2883
USPC
349/128
Abstract

The present invention provides a liquid crystal display device which can decrease lowering of light utilization efficiency attributed to a light absorption axis of an alignment film. A liquid crystal display device includes a liquid crystal display panel and a backlight arranged on a back surface of the liquid crystal display panel. The liquid crystal display panel includes liquid crystal, and a first substrate and a second substrate arranged to face each other in an opposed manner with the liquid crystal therebetween. The first substrate is arranged between the second substrate and the backlight. The first substrate includes a first polarizer and a first alignment film arranged between the first polarizer and the liquid crystal. The second substrate includes a second polarizer and a second alignment film arranged between the second polarizer and the liquid crystal. The second alignment film has a light absorption axis, and an angle made by the light absorption axis of the second alignment film and a light absorption axis of the second polarizer is set to a value which falls within ±1°. The first alignment film has a light absorption axis, and an angle made by the light absorption axis of the first alignment film and a light absorption axis of the first polarizer is set to a value not less than 89° and not more than 91°. (degree of polarization of the first alignment film)/(degree of polarization of the second alignment film) is set to a value not more than 0.9.

Claims (30)

1. A liquid crystal display device comprising:

a liquid crystal display panel; and

a backlight arranged on a back surface of the liquid crystal display panel, wherein

the liquid crystal display panel includes liquid crystal, and a first substrate and a second substrate arranged to face each other in an opposed manner with the liquid crystal therebetween,

the first substrate is arranged between the second substrate and the backlight,

the first substrate includes a first polarizer and a first alignment film arranged between the first polarizer and the liquid crystal,

the second substrate includes a second polarizer and a second alignment film arranged between the second polarizer and the liquid crystal,

the second alignment film has a light absorption axis, and an angle made by the light absorption axis of the second alignment film and a light absorption axis of the second polarizer is set to a value which falls within ±1°,

the first alignment film has a light absorption axis, and an angle made by the light absorption axis of the first alignment film and a light absorption axis of the first polarizer is set to a value not less than 89° and not more than 91°, and

(degree of polarization of the first alignment film)/(degree of polarization of the second alignment film) is set to a value not more than 0.9.

2. A liquid crystal display device according to claim 1 , wherein light alignment treatment is applied to the first alignment film and the second alignment film.

3. A liquid crystal display device according to claim 2 , wherein a radiation quantity of light at the time of applying light alignment to the first alignment film is smaller than a radiation quantity of light at the time of applying light alignment to the second alignment film.

4. A liquid crystal display device according to claim 2 , wherein a film thickness of the first alignment film is set smaller than a film thickness of the second alignment film.

5. A liquid crystal display device according to claim 1 , wherein (degree of polarization of the first alignment film)/(degree of polarization of the second alignment film) is set to a value not more than 0.7.

6. A liquid crystal display device according to claim 1 , wherein (degree of polarization of the first alignment film)/(degree of polarization of the second alignment film) is set to a value not more than 0.5.

7. A liquid crystal display device according to claim 1 , wherein (degree of polarization of the first alignment film)/degree of polarization of the second alignment film) is set to a value not less than 0.3.

8. A liquid crystal display device according to claim 1 , wherein the first substrate includes a pixel electrode and a counter electrode within a pixel region thereof, and the liquid crystal is driven by an electric field generated between the pixel electrode and the counter electrode.

9. A liquid crystal display device comprising:

a liquid crystal display panel; and

a backlight arranged on a back surface of the liquid crystal display panel, wherein

the liquid crystal display panel includes liquid crystal, and a first substrate and a second substrate arranged to face each other in an opposed manner with the liquid crystal therebetween,

the first substrate is arranged between the second substrate and the backlight,

the first substrate includes a first polarizer and a first alignment film arranged between the first polarizer and the liquid crystal,

the second substrate includes a second polarizer and a second alignment film arranged between the second polarizer and the liquid crystal,

the second alignment film has a light absorption axis, and an angle made by the light absorption axis of the second alignment film and a light absorption axis of the second polarizer is set to a value which falls within ±1°,

the first alignment film has a light absorption axis, and an angle made by the light absorption axis of the first alignment film and a light absorption axis of the first polarizer is set to a value which falls within ±1°, and

the alignment direction of the first alignment film is set to make an angle of not less than 60° and not more than 120° with respect to the direction of the light absorption axis of the first alignment film.

10. A liquid crystal display device according to claim 9 , wherein both light alignment treatment and rubbing treatment are applied to the first alignment film, and light alignment treatment is applied to the second alignment film.

11. A liquid crystal display device according to claim 10 , wherein the rubbing treatment is applied to the first alignment film after applying the light alignment treatment to the first alignment film.

12. A liquid crystal display device according to claim 9 , wherein the first substrate includes a pixel electrode and a counter electrode within a pixel region thereof, and the liquid crystal is driven by an electric field generated between the pixel electrode and the counter electrode.