ILLUMINATION DEVICE AND LIQUID CRYSTAL DISPLAY DEVICE

• US 20090207339A1
• Filed: 05/25/2007
• Published: 08/20/2009
• Est. Priority Date: 10/27/2006
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Ajichi, Yuhsaku, Masuda, Takeshi
• Granted Patent: US 7,920,227 B2
• Time in Patent Office: Days
• US Class Current: 349/64
• CPC Class Codes: G02B 5/0242 by means of dispersed particles
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 6/0021 for housing at least a part of the light source, e.g. by forming holes or recesses
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity
• CPC Class Codes: G02F 1/133613 characterized by the sequence of light sources

Abstract

A liquid crystal display device (1) of the present invention includes a display panel (3) and a backlight (2) (an illumination device). The backlight (2) includes a light-emitting layer (20) in which a plurality of light sources (5) are scattered and a diffuser (7) (a diffusion layer) that is formed on the light-emitting layer and diffuses light from the light-emitting layer. The light sources (5) that are present within the light-emitting layer (20) emit light in a direction (a direction of an arrow) substantially parallel to a boundary surface between the light-emitting layer (20) and the diffuser (7). In the diffuser (7), a transmittance of light in an area (7c) close to each of the light sources is smaller than a transmittance of light in an area that is far from each of the light sources.

Claims

1. An illumination device comprising:

a light-emitting layer in which a plurality of light sources are scattered; and

a diffusion layer that is formed on the light-emitting layer and diffuses light from the light-emitting layer,

the diffusion layer having a transmittance of light in an area close to each of the light sources which transmittance is smaller than a transmittance of light in an area that is far from each of the light sources,

the light sources each having directivity in a light emission direction, the directivity being such that a light component in a direction parallel to a boundary surface between the light-emitting layer and the diffusion layer is larger than a light component in a direction perpendicular to the boundary surface.

2. The illumination device as set forth in claim 1, wherein:

light emission directions of at least two light sources out of the plurality of light sources are different from each other.

3. The illumination device as set forth in claim 1, wherein:

each of the light sources is made of a light emitting diode.

4. The illumination device as set forth in claim 1, wherein:

in the diffusion layer, as a distance from each of the light sources increases, a size of diffusing particles that are filled in the diffusion layer becomes smaller.

5. The illumination device as asset forth in claim 1, wherein:

in the diffusion layer, as a distance from each of the light sources increases, a density of the diffusing particles that are filled in the diffusion layer becomes smaller.

6. The illumination device as set forth in claim 1, wherein:

in the diffusion layer, a reflecting material that reflects light is provided in the area that is close to each of the light sources.

7. The illumination device as set forth in claim 1, wherein:

a light-shielding treatment is provided between an area in which each of the light sources is provided in the light-emitting layer and the diffusion layer.

8. The illumination device as set forth in claim 1, wherein:

at least two light sources of the light sources are provided so as to face each other, and one of the two light sources is arranged to provide light towards another one of the two light sources.

9. A liquid crystal display device comprising, as a backlight, an illumination device as set forth in claim 1.

10. A liquid crystal display device comprising, as a backlight, an illumination device as set forth in claim 2.

11. A liquid crystal display device comprising, as a backlight, an illumination device as set forth in claim 3.

12. A liquid crystal display device comprising, as a backlight, an illumination device as set forth in claim 4.

13. A liquid crystal display device comprising, as a backlight, an illumination device as set forth in claim 5.

14. A liquid crystal display device comprising, as a backlight, an illumination device as set forth in claim 6.

15. A liquid crystal display device comprising, as a backlight, an illumination device as set forth in claim 7.

16. A liquid crystal display device comprising, as a backlight, an illumination device as set forth in claim 8.