Light guide plate, and backlight module and liquid crystal display incorporating same

• US 8,033,709 B2
• Filed: 08/02/2006
• Issued: 10/11/2011
• Est. Priority Date: 03/15/2006
• Status: Active Grant

• Current Assignee: Optronic Sciences LLC
• Original Assignee: AU Optronics Corporation
• Inventors: Chen, Chih-Kuang, Kao, Ko-Chia
• Primary Examiner(s): CARTER, WILLIAM JOSEPH
• Application Number:
  US11/461,801
• Publication Number:
  US 20070217224A1
• Time in Patent Office: 1,896 Days
• Field of Search: 362600-634
• US Class Current: 362/621
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/0065 Manufacturing aspects; Material aspects
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]

Abstract

A light guide plate for a liquid crystal display is disclosed. The light guide plate is adapted for use in a side-light emission type of backlight module. The light guide plate comprises a light incidence face that has at least one surface having at least one annular protrusion or recess, thereby enhancing the capability of light diffusion, uniformity of the light distribution, as well as promoting brightness.

Claims

1. A light guide plate comprising:

a light incidence face, the light guide plate being tapered from the light incidence face to a side opposite the light incidence face;

a plurality of incidence areas, each incidence area comprising a plurality of surfaces formed by a plurality of elliptically-shaped closed curves defining protrusions or recesses having different sizes arranged alternately in a matrix arrangement along a first direction and a second direction which is substantially perpendicular to the first direction, wherein each of plurality of incidence areas is spaced apart from adjacent incidence areas by areas devoid of the elliptically-shaped closed curves, and wherein the plurality of incidence areas collectively cover more than half a surface area of the light incidence face, and wherein each incidence area further comprises spacing between the protrusions or recesses where the protrusions or recesses and the spacing are distributed such that the protrusions or recesses cover more than half a surface area of each incidence area; and

a light emission face substantially perpendicular to the light incidence face, wherein the first direction is perpendicular to the emission face.

2. The light guide plate as claimed in claim 1, wherein the closed curves of the light incidence face forms a plurality of convex surfaces.

3. The light guide plate as claimed in claim 2, wherein the plurality of convex surfaces are irregularly distributed on the light incidence area.

4. The light guide plate as claimed in claim 2, wherein the plurality of convex surfaces are regularly distributed on the light incidence area.

5. The light guide plate as claimed in claim 1, wherein the light guide plate is made of Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PMMA).

6. A backlight module, for use in a liquid crystal display, comprising:

the light guide plate as claimed in claim 1; and

at least one light source disposed adjacent to the light incidence face.

7. The backlight module as claimed in claim 6, wherein the at least one light source is an LED.

8. The backlight module as claimed in claim 7, wherein the LED is a white LED.

9. The backlight module as claimed in claim 6, wherein the at least one light source is a cold cathode fluorescent lamp.

10. The backlight module as claimed in claim 6, wherein the light guide plate is made of Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PMMA).

11. The backlight module as claimed in claim 6, further comprising a reflective sheet disposed under the light guide plate.

12. A display device, comprising:

a display panel; and

the backlight module as claimed in claim 6 disposed under the display panel.

13. The display device as claimed in claim 12, further comprising at least one optical sheet disposed between the display panel and the backlight module.

14. The light guide plate as claimed in claim 1, wherein the protrusions or recesses having different sizes arranged alternately are further along a second direction which is substantially perpendicular to the first direction.