An optical film includes a rough surface having multiple measuring points constituting multiple virtual measuring planes in a given unit measuring area. A normal to each virtual measuring plane has an angle with a normal to a reference plane. On the reference plane, the projection area of the virtual measuring planes having the angle larger than 20 degrees ranges from 31% to 60% of the projection area of the given unit measuring area. The projection area of the virtual measuring planes having the angle larger than 50 degrees is less than 7% of the projection area of the given unit measuring area. 25% of the measuring points has the height larger than a first height. 75% of the measuring points has the height larger than a second height. The first height and the second height have a difference not less than 0.6 μm and not larger than 2.5 μm.