Patent ID: 8305511

Claim:
A backlight module, comprising: a beam splitting film, comprising: a light transmissive plate, having a first surface and a second surface opposite to the first surface, wherein the first surface is a light emitting surface; and a plurality of strip protrusion groups, disposed on the second surface, wherein each of the strip protrusion groups comprises a first strip protrusion and a second strip protrusion, the first strip protrusion and the second strip protrusion are disposed on the second surface and adjacent to each other, the first strip protrusion of each of the strip protrusion groups has a first strip surface and a second strip surface, the first strip surface and the second strip surface are inclined relative to the second surface, the second strip protrusion of each of the strip protrusion groups has a third strip surface and a fourth strip surface, the third strip surface and the fourth strip surface are inclined relative to the second surface, the second strip surface is located between the first strip surface and the third strip surface, the third strip surface is located between the second strip surface and the fourth strip surface, an inclining direction of the first strip surface relative to the second surface is the same as an inclining direction of the third strip surface relative to the second surface, an inclining direction of the second strip surface relative to the second surface is the same as an inclining direction of the fourth strip surface relative to the second surface, an average slope of the first strip surface relative to the second surface is not equal to an average slope of the third strip surface relative to the second surface, and an average slope of the second strip surface relative to the second surface is not equal to an average slope of the fourth strip surface relative to the second surface; a light guide plate, disposed at a side of the beam splitting film, wherein the light guide plate has a third surface, a fourth surface opposite to the third surface, and two light incident surfaces connected to the third surface and the fourth surface, the two light incident surfaces are respectively located at two opposite sides of the light guide plate, the third surface is located between the second surface and the fourth surface, and the second surface is located between the first surface and the third surface; and two light emitting devices, respectively disposed beside the two light incident surfaces and capable of emitting two light beams, wherein the two light beams are respectively capable of entering the light guide plate through the two light incident surfaces, and are capable of being transmitted to the beam splitting film through the third surface, and the two light emitting devices are capable of alternately flickering.