Patent ID: 8368841

Claim:
A backlight module, comprising: at least one point light source; and a light guide plate, comprising: a light emitting surface; a bottom surface, opposite to the light emitting surface; a light incident surface, connecting the light emitting surface and the bottom surface, wherein the point light source is disposed adjacent to the light incident surface; a first microstructure, formed on the light incident surface; a first side surface, opposite to the light incident surface, and connecting the light emitting surface and the bottom surface; a second side surface, connecting the light emitting surface, the bottom surface, the light incident surface, and the first side surface; a third side surface, opposite to the second side surface and connecting the light emitting surface, the bottom surface, the light incident surface, and the first side surface; a second microstructure, formed on the second side surface for reflecting a light beam incident on the second microstructure into the light guide plate so that the reflected light beam from the second side surface travels toward the first side surface and is reflected by the bottom surface toward the emitting surface, and a third microstructure, formed on the third side surface for reflecting a light beam incident on the third microstructure into the light guide plate so that the reflected light beam from the third side surface travels toward the first side surface and is reflected by the bottom surface toward the emitting surface, wherein each of the second microstructure and the third microstructure comprises a plurality of pillars protrusive from the second side surface and the third side surface respectively, each of the plurality of pillars has a first inclined plane and a second inclined plane connecting the first inclined plane, wherein the light incident surface is closer to the first inclined plane than to the second inclined plane, and the length of the first inclined plane is greater than the length of the second inclined plane.