Light guide plate and backlight module including same

A backlight module includes a light guide plate and a plurality of light sources. The light guide plate includes a wedge-shaped light incident part and a flat panel. The wedge-shaped light incident part and the flat panel have a common bottom surface. The height of the wedge-shaped light incident part is greater than that of the flat panel. The wedge-shaped light incident part includes a light incident surface perpendicular to the bottom surface and a sloped surface sloping relative to the light incident surface and connects to the flat panel. The sloped surface defines a plurality of V-shaped grooves for preventing light leak. The flat panel includes a light emitting surface opposite to the bottom surface. The plurality of light sources is positioned adjacent to the light incident surface.

BACKGROUND

1. Technical Field

The present disclosure relates to a backlight module and a light guide plate used in the backlight module.

2. Description of Related Art

A backlight module is typically used for illuminating a liquid crystal panel. The backlight module includes a light source and a light guide plate adjacent to the light source for an even distribution of light emitted from the light source. However, a light usage ratio of the light guide plate is typically low.

Therefore, it is desirable to provide a light guide plate and a backlight module which can overcome the limitations described.

DETAILED DESCRIPTION

Referring toFIGS. 1 to 3, a backlight module100according to an exemplary embodiment, is disclosed. The backlight module100includes a light guide plate50and a number of light sources60positioned adjacent to the light guide plate50. In this embodiment, the light sources60are LEDs. The light guide plate50is made of plastic. The light guide plate50includes a wedge-shaped light incident part51adjacent to the light sources60and a flat panel52connected to the light incident part51away from the light sources60. The light incident part51and the panel52are integrally formed. The light incident part51and the panel52have a common bottom surface53. The panel52includes a light emitting surface54opposite to the bottom surface53. The light incident part51includes a light incident surface55adjacent to the light sources60, a connecting surface57connecting to the light incident surface55, and a sloped surface56connecting between the light emitting surface54and the connecting surface57. The light incident surface55is substantially perpendicular to the bottom surface53The connecting surface57is parallel to the bottom surface53. An LCD (not shown) is positioned on the light emitting surface54.

The sloped surface56defines a number of V-shaped grooves58. Each V-shaped groove58includes a first surface580and a second surface581connected to the first surface580. The first surface580is adjacent to the incident surface55relative to the second surface581. The height of the light incident part51(the distance between the bottom surface53and the connecting surface57) is about 0.7 millimeters (mm), the height of the panel52(the distance between the bottom surface53and the light surface54) is about 0.5 mm. The included angle a between the first surface580and the second surface581is in the range from about 20° to about 60°, and the depth of the V-shaped groove58is in the range from about 20 μm to about 50 μm.

When in use, light emitted from the light sources60enters into the light guide plate50through the light incident surface55. A first part of the light is directed to the sloped surface56and a second part of the light is directed to the bottom surface53and the panel52. The V-shaped grooves58can enlarge the incident angle of the first part of the light reaching the sloped surface56. When the incident angle is equal to or bigger than a total reflection angle of the light guide plate50, the first part of the light will be totally reflected by the first surface580towards the bottom surface53, and will not emit out of the light guide plate50through the first surface580. Even if the incident angle is still smaller than the total reflection angle, yet, as the incident angle is enlarged, the refraction angle will be enlarged accordingly, that is, the light emitted out of the light guide plate50through the first surface580is more probably directed to the second surface581and enters the light guide plate50again through the second surface581. In this way, light leaks from the sloped surface56is reduced or evenly emitted and a light usage ratio of the light guide plate50is enhanced.

It will be understood that the above particular embodiments are shown and described by way of illustration only. The principles and the features of the present disclosure may be employed in various and numerous embodiments thereof without departing from the scope of the disclosure. The above-described embodiments illustrate the scope of the disclosure but do not restrict the scope of the disclosure.