Backlight assembly, liquid crystal display device having the same, and method of manufacturing thereof

• US 7,824,093 B2
• Filed: 10/02/2007
• Issued: 11/02/2010
• Est. Priority Date: 10/02/2006
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Hwang, In-Sun, Kim, Hyoung-Joo, Shin, Taek-Sun, Kim, Heu-Gon, Yoon, Byung-Seo, Chung, Seung-Hwan
• Primary Examiner(s): CARIASO, ALAN B
• Application Number:
  US11/865,945
• Publication Number:
  US 20090180300A1
• Time in Patent Office: 1,127 Days
• Field of Search: 362/606, 362/607, 362/619, 362/620, 362/625, 362/626
• US Class Current: 362/626
• 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 6/0055 Reflecting element, sheet or layer

Abstract

A backlight assembly includes a light source, a light-guide plate (LGP), a reflective sheet and at least one optical sheet. The light source emits light. The LGP includes a light-incident surface, a light-reflecting surface and a light-emitting surface. The light-incident surface receives the light from the light source. The light-reflecting surface has a plurality of first prism patterns spaced apart from each other and flat portions formed between the first prism patterns, which are substantially perpendicular to the light-incident surface. The light-emitting surface has a plurality of second prism patterns formed thereon. The reflective sheet is disposed below the LGP. At least one optical sheet is disposed on the LGP.

Claims

1. A backlight assembly comprising:

a light source emitting light;

a light-guide plate (LGP) including a light-incident surface, a light-reflecting surface and a light-emitting surface, the light-incident surface receiving light from the light source, the light-reflecting surface having a plurality of first prism patterns spaced apart from each other and a plurality of flat portions each of which is formed between the first prism patterns, the flat portions being substantially perpendicular to the light-incident surface, and the light-emitting surface having a plurality of second prism patterns formed thereon;

a reflective sheet disposed below the LGP; and

at least one optical sheet disposed on the LGP,

wherein the first prism patterns comprise;

a first slanted surface being extended from a first flat portion of the light-reflecting surface toward the light-emitting surface;

a second slanted surface being extended from the first slanted surface toward the light-reflecting surface; and

a third slanted surface being extended from the second slanted surface and being connected to a second flat portion.

2. The backlight assembly of claim 1, the LGP further comprising a light-facing surface disposed opposite the light-incident surface wherein the LGP has a thickness stepwise decreasing from the light-incident surface to the light-facing surface.

3. The backlight assembly of claim 2, wherein the first prism patterns have a stripe shape substantially parallel with the light-incident surface.

4. The backlight assembly of claim 2, wherein the first prism patterns have an irregular curved shape when viewed from a plan view of the light-reflecting surface.

5. The backlight assembly of claim 1,

wherein the first slanted surface and third slanted surface are substantially parallel with each other.

6. The backlight assembly of claim 5, wherein the second prism patterns have a stripe shape substantially perpendicular to the first prism patterns.

7. The backlight assembly of claim 6, wherein an interior angle of each of the second prism patterns is in a range of about 80°

to about 150°

.

8. The backlight assembly of claim 6, wherein the optical sheet comprises a diffusion sheet.

9. The backlight assembly of claim 5, wherein the first and second slanted surfaces are substantially symmetric with respect to a normal line of the first flat portion.

10. The backlight assembly of claim 5, wherein the first and second slanted surfaces are substantially asymmetric with respect to a normal line of the first flat portion.

11. The backlight assembly of claim 10, wherein a projected width of the first slanted surface is greater than a projected width of the second slanted surface.

12. The backlight assembly of claim 6, wherein the optical sheet comprises a prism sheet having third prism patterns formed thereon, wherein the third prism patterns are connected to each other.

13. The backlight assembly of claim 12, wherein the third prism patterns have a stripe shape substantially parallel with the second prism patterns.

14. The backlight assembly of claim 12, wherein the third prism patterns have a stripe shape substantially perpendicular to the second prism patterns.

15. The backlight assembly of claim 12, wherein an interior angle of each of the third prism patterns is in a range of about 80°

to about 150°

.

16. The backlight assembly of claim 12, wherein a lower surface of the prism sheet is matted.

17. The backlight assembly of claim 12, wherein the optical sheet further comprises a protection sheet disposed on the prism sheet.

18. The backlight assembly of claim 1, wherein the second prism patterns are connected to each other.

19. The backlight assembly of claim 1, wherein the first prism patterns are spaced apart from each other at constant intervals.

20. The backlight assembly of claim 1, wherein an interval between the first prism patterns is decreased, as a distance from the light-incident surface is increased.

21. A liquid crystal display (LCD) device comprising:

a light source emitting light;

a light-guiding plate (LGP) including a light-incident surface receiving light from the light source, a light-reflecting surface having a plurality of first prism patterns spaced apart from each other and a plurality of flat portions each of which is formed between the first prism patterns, the flat portions being substantially perpendicular to the light-incident surface, and a light-emitting surface having a plurality of second prism patterns formed thereon;

a reflective sheet disposed below the LGP;

at least one optical sheet disposed on the LGP; and

an LCD panel disposed on the optical sheet to display an image,

wherein the first prism patterns comprise;

a first slanted surface being extended from a first flat portion of the light-reflecting surface toward the light-emitting surface;

a second slanted surface being extended from the first slanted surface toward the light-reflecting surface; and

a third slanted surface being extended from the second slanted surface and being connected to a second flat portion.

22. The LCD device of claim 21, wherein the optical sheet comprises a prism sheet.

23. The LCD device of claim 22, wherein the optical sheet further comprises a protection sheet disposed on the prism sheet.

24. The LCD device of claim 21, wherein the optical sheet comprises a diffusion sheet.

25. A method of manufacturing a backlight assembly, the backlight assembly including a light source emitting light, a. light guide plate (LGP), a reflection sheet disposed below the LGP, and at least one optical member disposed on the LGP, the method comprising:

forming a plurality of first prism patterns on a light-reflecting surface of the LGP;

forming a plurality of flat portions between the prism patterns, the flat portions substantially perpendicular to a light-incident surface of the LGP; and

forming a plurality of second prism patterns on a light-emitting surface of the LGP;

wherein the light-incident surface receives light emitted from the light source,

wherein the first prism patterns comprise;

a first slanted surface being extended from a first flat portion of the light-reflecting surface toward the light-emitting surface;

a second slanted surface being extended from the first slanted surface toward the light-reflecting surface; and

a third slanted surface being extended from the second slanted surface and being connected to a second flat portion.

26. The method of claim 25, wherein the LGP has a thickness stepwise decreasing from the light-incident surface to the light-facing surface;

wherein further, the light-facing surface is disposed opposite the light-incident surface.

27. The method of claim 26, wherein the first prism patterns have a stripe shape substantially parallel with the light-incident surface.

28. A backlight assembly comprising:

a light source emitting light;

a light-guide plate (LGP) including a light-incident surface, a light-reflecting surface and a light-emitting surface, the light-incident surface receiving light from the light source, the light-reflecting surface having a plurality of first prism patterns spaced apart from each other and a plurality of flat portions each of which is formed between the first prism patterns, the flat portions being substantially perpendicular to the light-incident surface, and the light-emitting surface having a plurality of second prism patterns formed thereon;

a reflective sheet disposed below the LGP; and

at least one optical sheet disposed on the LGP,

wherein the first prism patterns comprise;

a first slanted surface being extended from a first flat portion of the light-reflecting surface toward the light-emitting surface;

a second slanted surface being extended from the first slanted surface toward the light-reflecting surface;

a connection surface formed substantially parallel with the first flat portion and being connected to the second slanted surface; and

a third slanted surface extended from the connection surface and being connected to a second flat portion.