Backlight assembly, liquid crystal display apparatus having the same, and method thereof

• US 7,847,882 B2
• Filed: 10/19/2007
• Issued: 12/07/2010
• Est. Priority Date: 10/19/2006
• Status: Expired due to Fees

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choi, Jin-Sung, Hwang, In-Sun, Kim, Hyoung-Joo, Shim, Sung-Kyu, Shin, Taek-Sun, Kim, Heu-Gon, Yoon, Byung-Seo
• Primary Examiner(s): Caley; Michael H
• Application Number:
  US11/875,249
• Publication Number:
  US 20080094552A1
• Time in Patent Office: 1,145 Days
• Field of Search: 349/64, 349/65, 349/95, 362/606, 362/607, 362/620, 362/626, 362/97.1, 362/97.2
• US Class Current: 349/64
• 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 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer

Abstract

A backlight assembly includes a light source, a light-guide plate, a reflective sheet, a first prism sheet, a second prism sheet and a lateral reflective sheet. The light source generates light. The light-guide plate guides the light and has a plurality of first prism patterns adjacent to each other. The first prism patterns are formed on a first surface of the light-guide plate. The reflective sheet is disposed adjacent the first surface of the light-guide plate. The first and second prism sheets are disposed on a second surface of the light-guide plate. The lateral reflective sheet is disposed on the second prism sheet. The lateral reflective sheet includes reflective protrusions substantially parallel with a longitudinal direction of the light source. Therefore, brightness and display quality may be enhanced.

Claims

1. A backlight assembly comprising:

a light source generating light;

a light-guide plate guiding the light generated from the light source toward a second surface of the light-guide plate and having a plurality of first prism patterns adjacent to each other, the first prism patterns formed on a first surface of the light-guide plate, the first surface being opposite to the second surface of the light-guide plate; and

a lateral reflective sheet disposed over the second surface of the light-guide plate and comprising reflective protrusions each defined by opposing side surfaces substantially parallel to each other and protruding in a direction opposite to the second surface of the light-guide plate; and

an optical sheet disposed between the light-guide plate and the lateral reflective sheet.

2. The backlight assembly of claim 1, wherein the light source is a lamp, and the lateral reflective sheet comprises reflective protrusions substantially parallel with a longitudinal direction of the lamp.

3. The backlight assembly of claim 2, wherein each of the reflective protrusions has a substantially rectangular cross-section when viewed on a plane substantially perpendicular to the longitudinal direction of the lamp.

4. The backlight assembly of claim 3, wherein a pitch of the reflective protrusions is from about 1 μ

m to about 100 μ

m.

5. The backlight assembly of claim 4, wherein a ratio of a width of the reflective protrusions to the pitch of the reflective protrusions is from about 10% to about 90%.

6. The backlight assembly of claim 5, wherein a height of the reflective protrusions is from about 1 μ

m to about 100 μ

m.

7. The backlight assembly of claim 3, wherein the reflective protrusions have a rounded corner.

8. The backlight assembly of claim 2, wherein a cross-section of each of the reflective protrusions has a substantially parallelogram shape when viewed on a plane substantially perpendicular to the longitudinal direction of the lamp.

9. The backlight assembly of claim 2, wherein the first prism patterns extend along a direction substantially perpendicular to the longitudinal direction of the lamp.

10. The backlight assembly of claim 9, further comprising first and second prism sheets disposed between the light-guide plate and the lateral reflective sheet, and wherein a first surface of the first prism sheet faces the second surface of the light-guide plate, and a second surface of the first prism sheet comprises second prism patterns adjacent to each other, and a first surface of the second prism sheet faces the first prism sheet, and a second surface of the second prism sheet comprises third prism patterns adjacent to each other.

11. The backlight assembly of claim 10, wherein the second prism patterns and the third prism patterns extend along a direction substantially parallel with the longitudinal direction of the lamp and are substantially perpendicular to the first prism patterns.

12. The backlight assembly of claim 2, wherein thickness of the light-guide plate decreases as a distance from the lamp increases.

13. The backlight assembly of claim 1, further comprising first and second prism sheets disposed between the light-guide plate and the lateral reflective sheet, and wherein the lateral reflective sheet includes a first surface facing the first and second prism sheets, and a second surface opposite the first surface, the second surface including a plurality of reflective protrusions which are spaced from each other.

14. The backlight assembly of claim 13, wherein the first and second prism sheets include second and third prism patterns, respectively, and the plurality of reflective protrusions extend substantially parallel to the second and third prism patterns.

15. A liquid crystal display apparatus comprising:

a lamp generating light;

a light-guide plate guiding the light generated from the lamp;

a lateral reflective sheet disposed on the light-guide plate and including reflective protrusions each defined by opposing side surfaces substantially parallel to each other and protruding in a direction opposite to the light-guide plate and disposed along a direction substantially parallel with a longitudinal direction of the lamp;

at least one optical sheet disposed between the light-guide plate and the lateral reflective sheet; and

a liquid crystal display panel that displays an image and is disposed on the lateral reflective sheet.

16. The liquid crystal display apparatus of claim 15, wherein each of the reflective protrusions has a substantially rectangular cross-section when viewed on a plane substantially perpendicular to the longitudinal direction of the lamp.

17. The liquid crystal display apparatus of claim 16, wherein the reflective protrusions have a pitch from about 1 μ

m to about 100 μ

m, and a height from about 1 μ

m to about 100 μ

m, and a ratio of a width of the reflective protrusions to the pitch of the reflective protrusions is from about 10% to about 90%.

18. The liquid crystal display apparatus of claim 17, wherein the light-guide plate includes a first surface and an opposite second surface through which the light exits, the lateral reflective sheet is disposed on the second surface of the light-guide plate, and the first surface of the light-guide plate includes first prism patterns adjacent to each other and extending in a direction substantially perpendicular to the longitudinal direction of the lamp.

19. The liquid crystal display apparatus of claim 18, further comprising:

a reflective sheet adjacent the first surface of the light-guide plate.

20. The liquid crystal display apparatus of claim 19, wherein the at least one optical sheet comprises:

a first prism sheet having a first surface facing the second surface of the light-guide plate and a second surface, the second surface of the first prism sheet including second prism patterns; and

a second prism sheet having a first surface facing the second surface of the first prism sheet and a second surface, the second surface of the second prism sheet including third prism patterns

wherein the second prism patterns and the third prism patterns extend along a direction substantially parallel with the longitudinal direction of the lamp.