BACKLIGHT DEVICE AND LIQUID CRYSTAL DISPLAY APPARATUS

• US 20060256255A1
• Filed: 05/08/2006
• Published: 11/16/2006
• Est. Priority Date: 05/11/2005
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Minami, Masaru
• Granted Patent: US 8,760,602 B2
• Time in Patent Office: Days
• US Class Current: 349/65
• 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 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members

Abstract

A direct backlight device including a light source arranged on the rear surface of a light-guiding plate and a liquid crystal display apparatus including the backlight device are provided, in which light extracting efficiency from the light-guiding plate is improved and luminance can be prevented from lowering or can be improved. The backlight device includes a light source arranged on the rear surface opposite to a light-emitting surface, and a reflective-angle modified portion, for example, a concave-convex portion formed by sandblast to modify a reflective angle of light emitted from the light source is provided at least on the light-emitting surface and/or the rear surface. A light reflective angle equal to or smaller than the critical angle is modified to improve the light extracting efficiency from the light-emitting surface.

Claims

1. A backlight device comprising:

a light source arranged on the rear surface opposite to a light-emitting surface of a light-guiding plate,

wherein a reflective-angle modified portion that modifies a reflective angle of light emitted from the light source is provided at least on said light-emitting surface and/or said rear surface of said light-guiding plate.

2. A backlight device according to claim 1,

wherein said reflective-angle modified portion is made of a concave-convex portion.

3. A backlight device according to claim 1,

wherein said reflective-angle modified portion is provided on approximately the whole of said light-emitting surface and/or said rear surface.

4. A backlight device according to claim 1,

wherein said reflective-angle modified portion is further provided on the side surfaces of said light-guiding plate.

5. A backlight device according to claim 1,

wherein said light source is a light-emitting diode.

6. A liquid crystal display apparatus comprising:

a transmissive liquid crystal display panel and

a backlight device illuminating said liquid crystal display panel from the rear surface side,

wherein said backlight device includes a light source arranged on the rear surface opposite to a light-emitting surface of a light-guiding plate and

a reflective-angle modified portion that modifies a reflective angle of light emitted from the light source is provided at least on said light-emitting surface and/or said rear surface of said light-guiding plate.