Patent attributes
An optical film with a plurality of micro structures which are capable of collecting incident light to the frontal and normalized view angle of the optical film for reducing the chance of incident light returning to light guild plate so as to enhance light collecting efficiency is provided in the present invention. In an embodiment, the optical film is combined with a flat light source so as to form a backlight system. By means of the merit of the optical film, the quantities of the optical film can be reduced so that the backlight system can have characteristics of thin thickness and low production cost.