Optical film and backlight module using same

A backlight module, comprising:

• a light source;
• a light guide plate, which comprises a light incidence surface corresponding to and facing the light source;
• a reflector plate, which is arranged on a reflection surface of the light guide plate, and
• at least one optical film, which is arranged on a light exit surface of the light guide plate, the optical film having a light incidence surface and a light exit surface, wherein the light incidence surface corresponds to and faces the light exit surface of the light guide plate and the light incidence surface is provided with a plurality of microstructure lenses distributed thereon, the microstructure lenses each being of an irregular shape showing a curved and arc configuration raised on and projecting from the light incidence surface, and the light exit surface is provided with a plurality of prism microstructures,
• wherein the plurality of microstructure lenses have irregular sizes and shapes and each of the plurality of microstructure lenses is surrounded by multiple ones of the microstructure lenses such that each of the microstructure lenses has a periphery that is directly connected to the multiple ones of the microstructure lenses.