US Patent 7522802 Optical multilayer film and a backlight module utilizing the same

An optical multilayer film includes first and second optical layers, and a refracting layer. The first optical layer has a light-exit surface. The second optical layer has a light-incoming surface facing the light-exit surface of the first optical layer, and a light-outgoing surface opposite to the light-incoming surface and formed with a light-converging structure. The refracting layer is disposed between and is in contact with the first and second optical layers, is made from a transparent material, and has a refractive index that is smaller than that of the second optical layer.