Backlight unit

A technology for a light source part and a light source, which is applied in the field of the backlight source part, can solve the problems of small improvement effect of uneven light incidence and enlarged area of ​​uneven light incidence, etc.

Inactive Publication Date: 2009-06-17
HITACHI CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0015] In the downward prism sheet method disclosed in Japanese Patent No. 2739730, since the emitted light from the light guide plate is reflected and does not return, it is directly emitted in the normal direction at one time, so there is a disadvantage that the area where uneven light incidence can be visually recognized becomes larger.
In addition, even if a diffuser sheet is laminated on the downward prism sheet for the purpose of improving the unevenness of incident light, the effect of improving unevenness of incident light is small.
Therefore, the current situation is that it is limited to use in backlights with large non-display areas.

Method used

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Examples

Experimental program
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Effect test

Embodiment 7

[0106]Embodiment 7 differs from Embodiment 6 in that the angle θ1 of the first prism row 42 is 15°, and the angles ψ1 and ψ2 of the third prism row 52 are both 45°. The other configurations are the same as in Embodiment 6. Embodiment 8 differs from Embodiment 7 in that the first prism array 42 is arranged perpendicular to the side surface 2 a. Comparative Example 3 is different from Example 7 in that the first prism array 42 is arranged at an inclination of approximately 20° from the side surface 2 a. In Examples 7 and 8, compared with Comparative Example 3, both the front luminance and the light incident unevenness are good. Furthermore, compared with Example 7, Example 8 has slightly better front brightness. In this way, it is desirable that the first prism array 42 is arranged parallel to or perpendicular to the side surface 2a. Furthermore, it is desirable that the first prism array 42 is arranged parallel to the side surface 2a.

[0107] In Examples 9 and 10 and Compar...

Embodiment 11

[0108] The angle θ1 of the first prism row 42 in Examples 11 and 12 and Comparative Example 6 is different from that of Example 7, and the other configurations are the same as those of Example 7. Compared with Example 7 in which the angle θ1 is 15°, Example 11 in which the angle θ1 is 20° has lower frontal luminance and the same light incident unevenness. In Example 12 where the angle θ1 is 10°, compared with Example 7, the front brightness is good, and the light incident unevenness increases. In Comparative Example 6 where the angle θ1 is 25°, compared with Examples 7, 11, and 12, although the frontal luminance is lowered, the unevenness of incident light is at the same level. Thus, it is desirable that the angle θ1 is in the range of 20° or less.

Embodiment 13

[0109] Embodiments 13 and 14 and Comparative Examples 7 and 8 differ from Embodiment 7 in the angle θ2 of the first prism row 42 , and the other configurations are the same as Embodiment 7. In Example 13 where the angle θ2 is 40°, compared with Example 7 where the angle θ2 is 48°, the front luminance is lowered, and the light incident unevenness is the same. In Example 14 where the angle θ2 is 55°, compared with Example 7, the front luminance is lowered, and the light incident unevenness is increased. Compared with Examples 7, 13, and 14 in Comparative Examples 7 and 8 where the angle θ2 is 35° and 60°, respectively, although the frontal brightness is lowered, the difference in incident light is at the same level. Thus, it is desirable that the angle θ2 is in the range of 40° to 55°.

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Abstract

A backlight unit includes: light source; light guide plate surrounded by main surfaces and end surfaces, one end surface facing a light source designated as entrance surface, one main surface designated as emitting surface; first prism sheet provided above the light guide plate, having first prism columns on a top surface and second prism columns on a bottom surface, each first prism column has first ridge line parallel or perpendicular to the entrance surface, each second prism column has second ridge line extending in a different direction from the first ridge line; second prism sheet provided above the first prism sheet, having third prism columns abutting each other on a top surface, each third prism column has third ridge line extending in a direction different from the first and second ridge lines; and reflection sheet facing the light guide plate below the light guide plate.

Description

[0001] This application is based upon and claims the benefit of priority of prior Japanese patent applications filed on December 10, 2007 with application numbers P2007-318250 and P2007-319594 filed on December 11, 2007, the entire contents of which are hereby expressly adopted Incorporated herein by reference. technical field [0002] The present invention relates to a backlight unit used in transmissive or semi-transmissive liquid crystal display elements, advertising boards, emergency lights, and the like. Background technique [0003] In recent years, color liquid crystal display devices have been widely used in various fields as mobile phones, portable notebook computers, portable liquid crystal televisions, and video-integrated liquid crystal televisions. This liquid crystal display device is basically composed of a backlight unit and a liquid crystal display element unit. As the backlight unit, there are a direct type in which a light source is provided directly unde...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F21V8/00F21V5/02F21V7/00G02F1/13357F21Y101/02
Inventor 田谷昌人小松德太郎杉本靖奥田唯史手岛照雄
Owner HITACHI CHEM CO LTD
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