# US 2010/0165249 A1 · Liquid crystal display device with a backlight unit having a diffusion plate

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- Number: US 2010/0165249 A1
- Document ID: US20100165249A1
- Status: Published application
- Kind: A1
- Application number: 12/659,394
- Filed: 2010-03-08
- Published: 2010-07-01
- Earliest claimed: 2006-07-03
- Assignees: Hitachi Displays, Ltd.; IPS Alpha Technology, Ltd.
- Inventors: Yoshihiro Imajo; Yoshifumi Sekiguchi; Hitoshi Taniguchi; Ikuo Hiyama
- Web page: https://patentgrep.com/patent/US20100165249A1

## CPC

- G02F 1/133606: {including a specially adapted diffusing, scattering or light controlling members}
- G02B 5/0263: {with positional variation of the diffusing properties, e.g. gradient or patterned diffuser}
- G02B 5/0278: {used in transmission}
- G02B 5/0294: {adapted to provide an additional optical effect, e.g. anti-reflection or filter}
- G02F 1/133611: {including means for improving the brightness uniformity}
- G02F 1/133607: {the light controlling member including light directing or refracting elements, e.g. prisms or lenses}
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A liquid crystal display device having a direct backlight which uses a high-bright light source achieves both of a high efficiency and thin uniformity. In a liquid crystal display device which includes a liquid crystal panel, and a backlight unit which is arranged on a side of the liquid crystal panel opposite to a display screen of the liquid crystal panel, the backlight unit includes a housing, a plurality of light sources arranged in the inside of the housing, and a diffusion plate which is arranged between the plurality of light sources and the liquid crystal panel, the diffusion plate includes a plurality of light blocking regions at positions corresponding to the plurality of respective light sources, and the light blocking region at a center portion of the housing and the light blocking region at an edge portion of the housing exhibits transmissivities different from each other.

## Claims

### Claim 1

A liquid crystal display device comprising:
a liquid crystal panel; and
a backlight unit which is arranged on a side of the liquid crystal panel opposite to a display screen of the liquid crystal panel, wherein
the backlight unit includes:
a housing;
a plurality of light sources arranged in the inside of the housing; and
a diffusion plate which is arranged between the plurality of light sources and the liquid crystal panel,
the diffusion plate includes a plurality of light blocking regions at positions corresponding to the plurality of respective light sources, and the light blocking region at a center portion of the housing and the light blocking region at an edge portion of the housing exhibits transmissivities different from each other.

### Claim 2 (depends on 1)

A liquid crystal display device according to claim 1, wherein the light source is a hot cathode fluorescent lamp (HCFL).

### Claim 3 (depends on 1)

A liquid crystal display device according to claim 1, wherein crest-like irregularities arranged parallel to the longitudinal direction of the light source are formed on the light blocking region.

### Claim 4 (depends on 3)

A liquid crystal display device according to claim 3, wherein the crest shape of the light blocking region is a crest shape which has a narrow width at a center portion and a wide width at a peripheral portion.

### Claim 5 (depends on 3)

A liquid crystal display device according to claim 3, wherein respective crests of the irregularities of the light blocking region have a long ridge at a center side and a short ridge at a peripheral side.

### Claim 6 (depends on 3)

A liquid crystal display device according to claim 3, wherein a crest shape of the light blocking region at the edge portion of the housing is formed such that a housing-center-side shape and a housing-edge-side shape are formed in asymmetry providing the light source as a center, and the housing-edge-side exhibits the higher transmissivity.

### Claim 7 (depends on 1)

A liquid crystal display device according to claim 1, wherein the plurality of light blocking regions form a plurality of rectangular reflection patterns, and an area for forming the reflection patterns is narrower in the light blocking region at the edge portion of the housing than in the light blocking region at the center portion of the housing.