Display device

• US 20050195341A1
• Filed: 03/02/2005
• Published: 09/08/2005
• Est. Priority Date: 03/02/2004
• Status: Abandoned Application

• Current Assignee: Hitachi Display Devices Limited (Hitachi, Ltd.), Hitachi Displays Limited (Japan Display Incorporated)
• Original Assignee: Hitachi Display Devices Limited (Hitachi, Ltd.), Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: Koganezawa, Nobuyuki, Tokuyama, Hiroshi, Tobe, Akiyoshi
• Application Number:
  US11/068,801
• Publication Number:
  US 20050195341A1
• Time in Patent Office: Days
• US Class Current: 349/62
• CPC Class Codes: G02F 1/133603 with LEDs

Abstract

A display device includes an optical compensation sheet stacked body mounted on a back surface of a liquid crystal display panel, and a light guide plate mounted on a back surface of the optical compensation sheet stacked body. A first air layer is interposed between the optical compensation sheet stacked body and the light emitting surface of the light guide plate, and a plurality of diffusion plates are mounted on the light incident surface of the light guide plate. A reflection sheet is arranged to face the light guide plate, and an array of an LED chips is provided on a front surface of the reflection sheet. A second air layer is interposed between the light diffusion plates and the LED array. Light from the LED chips having a plurality of colors is mixed and effective optical path length can be prolonged, whereby the least coupling loss is obtained.

Claims

1. A display device comprising:

a liquid crystal display panel which is configured to sandwich a liquid crystal layer between a pair of transparent substrates which have electrodes for forming pixels on inner surfaces thereof;

an optical compensation sheet stacked body which is mounted on a back surface of the liquid crystal display panel;

a light guide plate which is mounted on a back surface of the optical compensation sheet stacked body, includes a light emitting surface which emits light by developing the light in a planar shape to a front surface which faces the liquid crystal display panel in an opposed manner, and includes a light incident surface which allows the light to be incident on a back surface which faces the light emitting surface in an opposed manner;

a first air layer which is interposed between the optical compensation sheet stacked body and the light emitting surface of the light guide plate;

a plurality of diffusion plates which are mounted on the light incident surface of the light guide plate;

a reflection sheet which is arranged to face the light incident surface of the light guide plate in an opposed manner;

an LED array which arranges an LED chip on a front surface of the reflection sheet; and

a second air layer which is interposed between the plurality of light diffusion plates and the LED array.

2. A display device according to claim 1, wherein the LED array is configured by arranging LED chips of a plurality of colors to portions corresponding to positions where a plurality of light diffusion plates are formed.

3. A display device according to claim 1, wherein assuming a distance from an arrangement surface of the plurality of LED chips to the back surface of the optical compensation sheet stacked body as 1, the plurality of the light diffusion plates are mounted at a position smaller than 0.3 from the arrangement surface of the plurality of LED chips.

4. A display device according to claim 2, wherein assuming a distance from an arrangement surface of the plurality of LED chips to the back surface of the optical compensation sheet stacked body as 1, the plurality of the light diffusion plates are mounted at a position smaller than 0.3 from the arrangement surface of the plurality of LED chips.

5. A display device according to claim 1, wherein the plurality of light diffusion plates are formed in a disc shape.

6. A display device according to claim 2, wherein the plurality of light diffusion plates are formed in a disc shape.

7. A display device according to claim 3, wherein the plurality of light diffusion plates are formed in a disc shape.

8. A display device according to claim 1, wherein the plurality of light diffusion plates are held on a back surface of the light guide plate.

9. A display device comprising:

a liquid crystal display panel which is configured to sandwich a liquid crystal layer between a pair of transparent substrates which have electrodes for forming pixels on inner surfaces thereof;

an optical compensation sheet stacked body which is mounted on a back surface of the liquid crystal display panel;

a light guide plate which is mounted on a back surface of the optical compensation sheet stacked body, includes a light emitting surface which emits light by developing the light in a planar shape to a front surface which faces the liquid crystal display panel in an opposed manner, and includes a light incident surface which allows the light to be incident on a back surface which faces the light emitting surface in an opposed manner;

a first air layer which is interposed between the optical compensation sheet stacked body and the light emitting surface of the light guide plate;

a diffusion sheet which is mounted on the light emitting surface of the light guide plate;

a reflection sheet which is arranged to face the light incident surface of the light guide plate in an opposed manner;

an LED array which arranges LED chips of a plurality of colors mounted on a front surface of the reflection sheet; and

a second air layer which is interposed between the light incident surface of the light guide plate and the LED array.

10. A display device according to claim 9, wherein assuming a distance from an arrangement surface of the LED chip to the back surface of the optical compensation sheet stacked body as 1, the light diffusion sheet is mounted at a position which falls within a range of 0.38 to 0.78 from the arrangement surface of the LED chip using the arrangement position of the LED chip as the reference.

11. A display device according to claim 10, wherein the diffusion sheet is held on the light emitting surface of the light guide plate.