Backlight device for liquid crystal display devices

• US 20030081402A1
• Filed: 06/19/2002
• Published: 05/01/2003
• Est. Priority Date: 10/30/2001
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Jeon, Seong-Man, Kim, Je-Hong
• Granted Patent: US 6,729,737 B2
• Time in Patent Office: Days
• US Class Current: 362/26
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• 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 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0071 with elongated shape, e.g. tube
• CPC Class Codes: G02B 6/0091 of the light source relative to the light guide G02B6/0021 takes precedence

Abstract

The present invention discloses a backlight device for a liquid crystal display device, which includes at least a lamp; at least a lamp housing surrounding the lamp and having an opening on a side; at least a light guide plate connected to the opening of the lamp housing, the light guide plate guiding light from the lamp; a reflector arranged on the rear surface of the light guide plate, the reflector reflecting the light from the lamp in a direction to the light guide plate; a pre-collimator disposed in the lamp housing between the lamp and the light guide plate; a diffusion sheet disposed on the front surface of the light guide plate; and a prism sheet disposed on the diffusion sheet.

Claims

1. A backlight device for a liquid crystal display device, comprising:

at least a lamp;

at least a lamp housing surrounding the lamp and having an opening on a side;

at least a light guide plate connected to the opening of the lamp housing, the light guide plate guiding light from the lamp;

a reflector arranged on the rear surface of the light guide plate, the reflector reflecting the light from the lamp in a direction to the light guide plate;

a pre-collimator disposed in the lamp housing between the lamp and the light guide plate;

a diffusion sheet disposed on the front surface of the light guide plate; and

a prism sheet disposed on the diffusion sheet;

wherein the lamp housing has lower and upper portions; and

wherein the lower and upper portions have first and second V-shaped grooves in the inner surfaces thereof.

2. The backlight device according to claim 1, wherein the lamp housing has a U shape.

3. The backlight device according to claim 1, wherein the first and second V-shaped grooves correspond and face to each other.

4. The backlight device according to claim 1, wherein the pre-collimator is fixed into the V-shaped grooves.

5. The backlight device according to claim 1, wherein the pre-collimator is formed of prism sheet that has a plurality of angular prism.

6. The backlight device according to claim 1, wherein the light guide plate includes a plurality of prismatic patterns at the bottom.

7. A backlight device for a liquid crystal display device, comprising:

at least a lamp;

at least a lamp housing surrounding the lamp and having an opening on a side;

at least a light guide plate connected to the opening of the lamp housing, the light guide plate guiding light from the lamp;

a reflector arranged on the rear surface of the light guide plate, the reflector reflecting the light from the lamp in a direction to the light guide plate;

a pre-collimator disposed in the lamp housing between the lamp and the light guide plate;

a diffusion sheet disposed on the front surface of the light guide plate; and

a prism sheet disposed on the diffusion sheet;

wherein the lamp housing has lower and upper portions; and

wherein the lower portion has a V-shaped groove in the inner surfaces thereof and the upper portion has a hole covered by a hole cover.

8. The backlight device according to claim 7, wherein the lamp housing has a U shape.

9. The backlight device according to claim 7, wherein the V-shaped groove of the lower portion corresponds and faces to the hole of the upper portion.

10. The backlight device according to claim 7, wherein the pre-collimator is inserted through the hole of the upper portion and fixed into the V-shaped groove of the lower portion.

11. The backlight device according to claim 7, wherein the hole cover is a silver (Ag) coated tape.

12. The backlight device according to claim 7, wherein the pre-collimator is formed of prism sheet that has a plurality of angular prism.

13. The backlight device according to claim 7, wherein the light guide plate includes a plurality of prismatic patterns at the bottom.

14. A backlight device for a liquid crystal display device, comprising:

at least a lamp;

at least a lamp housing surrounding the lamp and having an opening on a side;

at least a light guide plate connected to the opening of the lamp housing, the light guide plate guiding light from the lamp;

a reflector arranged on the rear surface of the light guide plate, the reflector reflecting the light from the lamp in a direction to the light guide plate;

a pre-collimator disposed in the lamp housing between the lamp and the light guide plate;

a diffusion sheet disposed on the front surface of the light guide plate; and

a prism sheet disposed on the diffusion sheet;

wherein the lamp housing has lower and upper portions; and

wherein the lower and upper portions have Z-bands each having a step.

15. The backlight device according to claim 14, wherein the lamp housing has a U shape.

16. The backlight device according to claim 14, wherein the Z-bends allows the lamp housing to have inner and outer widths between the lower and upper portions.

17. The backlight device according to claim 16, wherein the outer width is larger than the inner width by 400 to 600 micrometers.

18. The backlight device according to claim 14, wherein the pre-collimator is disposed at the Z-bends of the lower and upper portions of the lamp housing.

19. The backlight device according to claim 14, wherein the light guide plate and the reflector are attached to the pre-collimator to fix the pre-collimator.

20. The backlight device according to claim 14, wherein the step of Z-bends ranges from 200 to 300 micrometers.

21. The backlight device according to claim 14, wherein the pre-collimator is formed of prism sheet that has a plurality of angular prism.

22. The backlight device according to claim 14, wherein the light guide plate includes a plurality of prismatic patterns at the bottom.