IP Library Granted Patent US 7,791,697
Granted Patent B2
US 7,791,697 · App. 12/329,158 · Granted Sep 7, 2010

Liquid crystal display device

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Quick Facts
Patent No.
US 7,791,697
App. No.
12/329,158
Granted
Sep 7, 2010
Kind
B2
Abstract

A liquid crystal display device includes a first substrate, a second substrate arranged on a viewer side, and a liquid crystal between the first and second substrates. A light guide plate is arranged on a back surface of the first substrate, a polarization plate is arranged between the first substrate and the light guide plate, and a prism sheet is arranged between the light guide plate and the polarization plate with prisms being provided on a light guide plate side thereof. A diffusion layer is arranged between the prism sheet and the polarization plate, and a light control sheet is arranged between the diffusion layer and the polarization plate. The light control sheet, which is a λ/2 retardation plate, rotates a polarization of light emitted from the diffusion layer, is arranged in contact with the polarization plate.

Claims (31)

1. A liquid crystal display device comprising:

a first substrate;

a second substrate arranged on a viewer side as compared with the first substrate;

a liquid crystal held between the first substrate and the second substrate;

a light guide plate arranged on a back surface of the first substrate;

a polarization plate arranged between the first substrate and the light guide plate;

a prism sheet arranged between the light guide plate and the polarization plate and having prisms provided on a light guide plate side thereof;

a diffusion layer arranged between the prism sheet and the polarization plate; and

a light control sheet arranged between the diffusion layer and the polarization plate;

wherein the light control sheet rotates a polarization of light emitted from the diffusion layer;

wherein the light control sheet is a λ/2 retardation plate; and

wherein the light control sheet is arranged in contact with the polarization plate.

2. A liquid crystal display device according to claim 1 , wherein the light control sheet rotates the polarization of the light emitted from the diffusion layer so that an angle of a transmission axis of the polarization plate relative to a straight line, connected with points where each of R, G and B components of the light emitted from the light diffusion layer has substantially the same amplitude in polarization characteristics, falls within the range of ±10°.

3. A liquid crystal display device according to claim 2 , wherein the following expressions are satisfied:

−0.03≦( A 2− A 1)/ A 1≦0.03 and −0.03 ≦≦A 3− A 1)/ A 1≦≦0.03

where, A1 is any one of amplitudes of the R, G and B components, and A2 and A3 are the amplitudes of the other components at the straight line.

4. A liquid crystal display device comprising:

a first substrate;

a second substrate arranged on a viewer side compared with the first substrate;

a liquid crystal held between the first substrate and the second substrate;

a light guide plate arranged on a back surface of the first substrate;

a polarization plate arranged between the first substrate and the light guide plate;

a prism sheet arranged between the light guide plate and the polarization plate and having prisms provided on a light guide plate side thereof;

a diffusion sheet arranged between the prism sheet and the polarization plate; and

a light control sheet arranged between the diffusion sheet and the polarization plate;

wherein the light control sheet rotates a polarization of light emitted from the diffusion sheet so that an angle of the transmission axis of the polarization plate relative to a straight line, connected with points where each of R, G and B components of the light emitted from the diffusion layer has substantially the same amplitude in polarization characteristics, falls within the range of ±10°;

wherein the light control sheet is a λ/2 retardation plate; and

wherein the light control sheet is arranged in contact with the polarization plate.

5. A liquid crystal display device according to claim 4 , wherein the following expressions are satisfied:

−0.03≦( A 2− A 1)/ A 1≦0.03 and −0.03≦( A 3− A 1)/ A 1≦0.03

where, A1 is any one of the amplitudes of the R, G and B components, and A2 and A3 are the amplitudes of the other components at the straight line.

Assignments (7)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jul 10, 2025
From: JAPAN DISPLAY INC
To: MAGNOLIA PURPLE CORPORATION
Reel/Frame 071890/0202 →
CHANGE OF NAME Recorded Nov 17, 2023
From: HITACHI DISPLAYS, LTD.
To: JAPAN DISPLAY EAST, INC.
Reel/Frame 065614/0223 →
CHANGE OF NAME Recorded Nov 17, 2023
From: JAPAN DISPLAY EAST, INC.
To: JAPAN DISPLAY, INC.
Reel/Frame 065614/0644 →
CHANGE OF ADDRESS Recorded Nov 17, 2023
From: JAPAN DISPLAY, INC.
To: JAPAN DISPLAY, INC.
Reel/Frame 065654/0250 →
NUNC PRO TUNC ASSIGNMENT Recorded Nov 17, 2023
From: PANASONIC LIQUID CRYSTAL DISPLAY CO., LTD.
To: PANASONIC INTELLECTUAL PROPERTY CORPORATION OF AMERICA
Reel/Frame 065615/0327 →
MERGER Recorded Oct 14, 2011
From: IPS ALPHA SUPPORT CO., LTD.
To: PANASONIC LIQUID CRYSTAL DISPLAY CO., LTD.
Reel/Frame 027063/0139 →
COMPANY SPLIT PLAN TRANSFERRING FIFTY (50) PERCENT SHARE OF PATENTS Recorded Oct 14, 2011
From: HITACHI DISPLAYS, LTD.
To: IPS ALPHA SUPPORT CO., LTD.
Reel/Frame 027063/0019 →