Other types of optical films can also improve viewing angle characteristics of a TN LCD, but they cannot always improve the LCD's viewing angle characteristics in both vertical and horizontal directions.
Sharp says that its film, which is placed on the display, is scattering the light in oblique directions o its prevents degradation of the quality of an image viewed at an angle.
Most of the perpendicular light emitted from an LCD display comes into a transparent resin of the optical film. Then, part of the light is totally reflected from the boundaries with the voids. This means that light free from gradation inversion, color deviation, etc comes out in oblique directions.
The result is the limited degradation of the quality of an image viewed at an angle.