Backlight unit

• US 7,104,679 B2
• Filed: 12/23/2002
• Issued: 09/12/2006
• Est. Priority Date: 12/24/2001
• Status: Expired due to Term

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Shin, Hyun Ho, Kim, Je Hong, Jeon, Seong Man
• Primary Examiner(s): O'Shea, Sandra
• Assistant Examiner(s): Neils, Peggy A.
• Application Number:
  US10/325,973
• Publication Number:
  US 20030117793A1
• Time in Patent Office: 1,359 Days
• Field of Search: 362/31, 362/560, 362/327, 362/328, 362/330, 362/339, 362/26, 362/331, 362/623, 362/626, 362/615, 362/628, 385/146, 349/65
• US Class Current: 362/626
• CPC Class Codes: G02B 6/0025 Diffusing sheet or layer; Prismatic sheet or layer
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• 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 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0071 with elongated shape, e.g. tube

Abstract

There is provided a backlight unit that is capable of making it possible to highly condense light while simultaneously reducing costs. A backlight unit according to an embodiment of the present invention includes a light source for generating light; a lamp housing installed to cover the light source and for reflecting the light; and a light guide panel whereon there are formed a plurality of engraved patterns with a specific gap and a specific depth at the lower surface thereof, and wherein the vertical angle of the engraved pattern, which faces an out-coming surface of the light guide panel, is in a range of 30˜95°. Accordingly, it can be applicable to display panels of various sizes and a picture is improved at the same time. Also, in the backlight unit, it is possible to get rid of at least one of a prism sheet, a diffusion sheet and a reflecting sheet, thereby reducing costs. Moreover, this backlight unit can obtain a highly condensed light by using a light emitting diode that controls the curvature to condense the out-coming light within a specific angle.

Claims

1. A backlight unit, comprising:

a light source for generating light;

a lamp housing installed to cover the light source and for reflecting the light; and

a light guide panel comprising a plurality of engraved patterns with a specific gap between the patterns and a specific depth of the patterns with respect to a lower surface of the panel, and

wherein the vertical angle of the engraved patterns, which faces a light emission surface of the light guide panel, is in a range of from an angle greater than 55°

up to and including 95°

; and

wherein the engraved patterns are formed in the shape of a polygon, and the pitch has a first tilt angle and a second tilt angle that differs from the first tilt angle.

2. The backlight unit according to claim 1, further comprising:

a diffusion sheet for diffusing a light beam passed through the light guide panel; and

a prism sheet for controlling the progress direction of the light beam passed through the diffusion sheet.

3. The backlight unit according to claim 1, wherein the specific gap is formed relatively wider if the engraved pattern is closer to the light source, and relatively narrower if the engraved pattern is more distant from the light source.

4. The backlight unit according to claim 1, wherein the specific depth is formed by etching a lower surface of the light guide panel from a few μ

m up to dozens of μ

m in accordance with the size of a display panel.

5. The backlight unit according to claim 1, wherein the engraved pattern is formed with a distance of a few mm from an incident surface of the light guide panel.

6. The backlight unit according to claim 1, wherein a pitch of the engraved pattern is formed smaller if the pitch is located at a side surface area facing an incident surface of the light guide panel, and larger if the pitch is located at another area of the light guide panel.

7. The backlight unit according to claim 1, wherein at least one condenser having a prism pattern is formed between the light source and an incident surface of the light guide panel for condensing light.

8. The backlight unit according to claim 7, wherein the condenser is formed of Polymethyl Methacrylate PMMA.

9. The backlight unit according to claim 7, wherein the condenser has a first tilt angle and a second tilt angle formed on a lower surface of the condenser, and the first and second tilt angles are in a range of about 10˜

45°

.

10. The backlight unit according to claim 1, further comprising;

a reflecting plate formed facing the light guide panel at a lower part of the light guide panel.

11. The backlight unit according to claim 1, further comprising;

a reflecting part coated with reflecting metal to be formed on the engraved pattern at a lower surface of the light guide panel.

12. The backlight unit according to claim 11 wherein the reflecting metal is formed of aluminum Al or silver Ag.

13. The backlight unit according to claim 12, wherein the backlight unit is utilized in a display panel of 6 inches or less.

14. A backlight unit, comprising:

a light emitting diode lamp for emitting light within a specific angle; and

a light guide panel whereon there are formed a plurality of engraved patterns with a specific gap and a specific depth at a lower surface thereof, and

wherein the vertical angle of the engraved pattern, which faces a light emission surface of the light guide panel, is in a range of from an angle greater than 55°

up to and including 95°

.

15. The backlight unit according to claim 14, wherein the specific gap is formed relatively wider if the engraved pattern is closer to the light emitting diode, and relatively narrower if the engraved pattern is more distant from the light emitting diode.

16. The backlight unit according to claim 14, wherein the specific depth is formed by etching a lower surface of the light guide panel from a few μ

m up to dozens of μ

m in accordance with the size of a display panel.

17. The backlight unit according to claim 14, wherein the engraved pattern is formed with a distance of a few mm from an incident surface of the light guide panel.

18. The backlight unit according to claim 14, wherein a pitch of the engraved pattern is formed smaller if the pitch is located at a side surface area facing an incident surface of the light guide panel, and larger if the pitch is located at another area of the light guide panel.

19. The backlight unit according to claim 18, wherein the engraved pattern is formed in the shape of a triangle, and the pitch has a first and second tilt angle formed.

20. The backlight unit according to claim 14, wherein at least one condenser or prism pattern is formed between the light emitting diode and an incident surface of the light guide panel for condensing light.

21. The backlight unit according to claim 14, further comprising;

a reflecting plate formed facing the light guide panel at a lower part of the light guide panel.

22. The backlight unit according to claim 14, further comprising;

a reflecting part coated with reflecting metal to be formed on the engraved pattern at a lower surface of the light guide panel.

23. The backlight unit according to claim 22, wherein the reflecting metal is formed of aluminum Al or silver Ag.

24. The backlight unit according to claim 23, wherein the backlight unit is utilized in a display panel of 6 inches or less.