Light guide plate and backlight module using the same

Abstract

A light guide plate includes an emitting surface; a reflective surface opposite to the emitting surface; an incident surface interconnecting with the emitting surface and the reflective surface. A plurality of ridges are formed on the reflective surface. Each ridge has a first base angle and a second base with respect to the reflective surface. The first base angle closest to the incident surface is in a range from about 86 degrees to 90 degrees. The second base angle furthest from the incident surface is in a range from about 41.8 degrees to 45.8 degrees. A backlight module using the light guide plate is also provided. The present light guide plate and a backlight module using the same can efficiently increase light brightness.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the light guide plate and related backlight modules having the same can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present devices. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a schematic, isometric view of a backlight module according to a first preferred embodiment, the backlight module having a light guide plate, the light guide plate having an emitting surface, a reflective surface, an incident surface, and a plurality of ridges formed on the reflective surface;

FIG. 2 is a schematic, cross-sectional view taken along a II-II line of FIG. 1 showing each ridge having a first base angle θ₁ and a second base angle θ₂ with respect to the reflective surface;

FIG. 3 is a graph showing luminance intensity from the light guide plate at different angles perpendicular to the incident surface of four backlight module prototypes, three of which are present backlight module samples of FIG. 1 and the other of which is a conventional backlight module, the light guide plate of the conventional backlight module having no V-shaped protrusions.

FIG. 4 is a graph showing luminance intensity from the light guide plate at different angles parallel to the incident surface of four backlight module samples which are the same of FIG.3;

FIG. 5 is a graph showing luminance intensity from the light guide plate at different angles perpendicular to the incident surface of four backlight module samples, three of which are other present backlight module samples of FIG. 1 and the other of which is a conventional backlight module, the light guide plate of the conventional backlight module having no V-shaped protrusions;

FIG. 6 is a graph showing luminance intensity from the light guide plate at different angles parallel to the incident surface of four backlight module samples which are the same of FIG.5;

FIG. 7 is a schematic, isometric view of a backlight module according to a second preferred embodiment;

FIG. 8 a schematic, cross-sectional view of a conventional backlight module; and

FIG. 9 is schematic, cross-sectional view of another conventional backlight module.

Claims

1. A light guide plate, comprising: an emitting surface;a reflective surface opposite to the emitting surface;an incident surface interconnecting with the emitting surface and the reflective surface; anda plurality of ridges formed on the reflective surface, wherein each ridge has a first base angle and a second base with respect to the reflective surface, the first base angle closest to the incident surface being in a range from about 86 degrees to 90 degrees, and the second base angle furthest from the incident surface being in a range from about 41.8 degrees to 45.8 degrees.

2. The light guide plate according to claim 1, wherein each ridge extends out from the reflective surface along a direction parallel to the incident surface.

3. The light guide plate according to claim 2, wherein the ridges are similar in shape with each other, but are different in size, a distribution density and a relative size of the ridges progressively increasing with increasing distance from the incident surface, and respective distances between adjacent second ridges decreasing with increasing distance from the incident surface.

4. The light guide plate according to claim 2, wherein the ridges are selectively configured to be one of contiguous and discrete in a direction parallel to the incident surface.

5. The light guide plate according to claim 1, wherein the light guide plate is a flat sheet having a substantially rectangular shape from top view, the incident surface is disposed at a cut-out portion of the light guide plate extending from a corner of the emitting surface to a corresponding corner of the bottom surface, the ridges are arranged on the reflecting surface along a plurality of imaginary concentric circular arcs, such arcs centering on a reference point that is located adjacent the incident surface.

6. The light guide plate according to claim 5, wherein the ridges are similar in shape with each other, but are different in size, a distribution density and a relative size of the ridges progressively increasing with increasing distance from the incident surface, and respective distances between adjacent second ridges decreasing with increasing distance from the incident surface.

7. The light guide plate according to claim 5, wherein the ridges are selectively configured to be one of contiguous and discrete within a given imaginary arc.

8. The light guide plate according to claim 1, wherein heights of the ridges are in the range from 0.001 millimeters to about 0.02 millimeters.

9. The light guide plate according to claim 1, wherein the light guide plate is comprised of a material selected from polymethyl methacrylate, polycarbonate, and other suitable transparent resin materials.

10. A backlight module comprising: a light source, anda light guide plate having an emitting surface;a reflective surface opposite to the emitting surface;an incident surface interconnecting with the emitting surface and the reflective surface, the light source being positioned adjacent to the incident surface; anda plurality of ridges formed on the reflective surface, wherein each ridge has a first base angle and a second base with respect to the reflective surface, the first base angle closest to the incident surface being in a range from about 86 degrees to 90 degrees, and the second base angle furthest from the incident surface being in a range from about 41.8 degrees to 45.8 degrees.

11. The backlight module according to claim 10, wherein each ridge extends out from the reflective surface along a direction parallel to the incident surface.

12. The backlight module according to claim 11, wherein the ridges are similar in shape with each other, but are different in size, a distribution density and a relative size of the ridges progressively increasing with increasing distance from the incident surface, and respective distances between adjacent second ridges decreasing with increasing distance from the incident surface.

13. The backlight module according to claim 11, wherein the ridges are selectively configured to be one of contiguous and discrete in a direction parallel to the incident surface.

14. The backlight module according to claim 10, wherein the light guide plate is a flat sheet having a substantially rectangular shape from top view, the incident surface is disposed at a cut-out portion of the light guide plate extending from a corner of the emitting surface to a corresponding corner of the bottom surface, the ridges are arranged on the reflecting surface along a plurality of imaginary concentric circular arcs, such arcs centering on a reference point that is located adjacent the incident surface.

15. The backlight module according to claim 14, wherein the ridges have a similar shape but different sizes, a distribution density and a relative size of the ridges progressively increasing with increasing distance from the incident surface, and respective distances between adjacent second ridges decreasing with increasing distance from the incident surface.

16. The backlight module according to claim 14, wherein the ridges are selectively configured to be one of contiguous and discrete within a given imaginary arc.