SURFACE LIGHT SOURCE AND DISPLAY DEVICE

• US 20090180299A1
• Filed: 01/13/2009
• Published: 07/16/2009
• Est. Priority Date: 01/15/2008
• Status: Abandoned Application

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: OKADA, Yutaka, ITO, Shin
• Application Number:
  US12/352,971
• Publication Number:
  US 20090180299A1
• Time in Patent Office: Days
• US Class Current: 362/619
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0088 of the light guide or other optical sheets in the package
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

A surface light source includes: a light guiding plate including, in a main region, a light emitting surface and a back surface facing the light emitting surface; and a light source being provided on a back surface side in an end region of the light guiding plate, the light source emitting light so that the light emitted from the light emitting surface. The surface light source further includes: an inclining surface being formed along an end section on the light emitting surface side in the end region so that the light guiding plate becomes thinner toward the end section; a reflecting member covering the inclining surface; and a light incident end face being provided on the back surface side and extending along the end section, the inclining surface being formed so that light entering the light incident end face at a right angle is totally reflected by the light incident end face after being reflected by the inclining surface or the reflecting member. With this arrangement, it is possible to realize a surface light source that is larger in size and thinner in thickness, and a display device having a narrower frame.

Claims

1. A surface light source comprising:

a light guiding plate including, in a main region, a light emitting surface for emitting light and a back surface facing the light emitting surface;

a light source being provided on a back surface side in an end region of the light guiding plate, and emitting the light to be emitted from the light emitting surface;

an inclining surface being formed along an end section on the light emitting surface side in the end region so that the light guiding plate becomes thinner toward the end section;

a reflecting member covering the inclining surface; and

a light incident end face being provided on the back surface side and extending along the end section,

the inclining surface being formed so that light entering the light incident end face at a right angle is totally reflected by the light incident end face after being reflected by the inclining surface or the reflecting member.

2. The surface light source according to claim 1, wherein:

the end region of the light guiding plate has a notch between a first light incident end face and a second light incident end face,

the notch is provided along an end section of the back surface and is depressed toward the light emitting surface from a virtual extension surface of the back surface,

the first light incident end face is formed between the light source and the inclining surface, and the second light incident end face is substantially perpendicular to the first light incident end face.

3. The surface light source according to claim 2, wherein:

the second light incident end face has a plurality of recess sections; and

a surface formed with the plurality of recess sections forms an angle of (90−

2·

arc sin(1/n)) or less with a tangential plane of the second light incident end face, where n is a refractive index of the light guiding plate.

4. The surface light source according to claim 3, wherein the recess sections have a shape of substantially circular arc.

5. The surface light source according to claim 3, wherein the recess sections have a triangular shape.

6. A liquid crystal display device comprising:

a liquid crystal display panel; and

a surface light source including;

a light guiding plate including, in a main region, a light emitting surface for emitting light and a back surface facing the light emitting surface;

a light source being provided on a back surface side in an end region of the light guiding plate, and emitting the light to be emitted from the light emitting surface;

an inclining surface being formed along an end section on the light emitting surface side in the end region so that the light guiding plate becomes thinner toward the end section;

a reflecting member covering the inclining surface; and

a light incident end face being provided on the back surface side and extending along the end section,

the inclining surface being formed so that light entering the light incident end face at a right angle is totally reflected by the light incident end face after being reflected by the inclining surface or the reflecting member,

the liquid crystal display panel being backlighted by the surface light source.