Direct-illumination backlight apparatus having transparent plate acting as light guide plate

• US 20060187651A1
• Filed: 05/25/2005
• Published: 08/24/2006
• Est. Priority Date: 02/18/2005
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Inventors: Park, Young Sam, Ahn, Ho Sik, Kim, Hyung Suk, Jeong, Young June, Hahm, Hun Joo, Park, Jung Kyu, Kim, Bum Jin
• Granted Patent: US 7,273,291 B2
• Time in Patent Office: Days
• US Class Current: 362/27
• 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 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0041 provided in the bulk of the light guide
• CPC Class Codes: G02F 1/133603 with LEDs

Abstract

A direct-illumination backlight apparatus uses LEDs as a light source. This backlight apparatus comprises: a flat reflective plate; an LED light source arranged on the reflective plate; a transparent plate arranged above the LED light source; a scattering pattern arranged on an underside of the transparent plate in a position corresponding to the LED light source; and a light guide made of transparent material, and arranged around the scattering pattern to introduce light incident from below into the transparent plate so that the light is internally reflected by the transparent plate. The light guide serves to introduce a partial light from an LED light source at such an angle that the partial light is trapped inside the transparent plate, and the scattering pattern serves to scatter the trapped light beam at a position directly above the LED light source so that the scattered light beam escapes out of the transparent plate toward an LCD panel. This can remove any dark area above the LED light source in the transparent plate and thus reduce the thickness of the direct-illumination backlight apparatus.

Claims

1. A direct-illumination backlight apparatus, comprising:

a flat reflective plate;

an LED light source arranged on the reflective plate;

a transparent plate arranged above the LED light source;

a scattering pattern arranged on an underside of the transparent plate in a position corresponding to the LED light source; and

a light guide made of transparent material, and arranged around the scattering pattern to introduce light incident from below into the transparent plate so that the light is internally reflected by the transparent plate.

2. The direct-illumination backlight apparatus according to claim 1, wherein the light guide and the transparent plate have a same reflectivity.

3. The direct-illumination backlight apparatus according to claim 1, wherein the light guide is in close face-to-face contact with the transparent plate.

4. The direct-illumination backlight apparatus according to claim 1, wherein the light guide is made of a transparent material selected from a group consisting of glass, acryl, plastic, Polymethylmethacrylate (PMMA) and epoxy.

5. The direct-illumination backlight apparatus according to claim 1, wherein the light guide is shaped as an overturned prism, with a bottom of the light guide being attached to the underside of the transparent plate.

6. The direct-illumination backlight apparatus according to claim 1, wherein the light guide is bonded to the transparent plate via adhesive.

7. The direct-illumination backlight apparatus according to claim 6, wherein the adhesive has a transmissivity of at least 99%.

8. The direct-illumination backlight apparatus according to claim 1, wherein the scattering pattern is adapted to scatter and reflect light incident from inside the transparent plate.

9. The direct-illumination backlight apparatus according to claim 8, wherein the scattering pattern is adapted to reflect light incident from below the transparent plate.

10. The direct-illumination backlight apparatus according to claim 8, wherein the scattering pattern is adapted to transmit and reflect light incident from below the transparent plate while scattering the light.