Diffusion film

Patent Granted PROBLEM TO BE SOLVED: To provide a diffusion film having high resolution and wide viewing angle and capable of displaying a high contrast image by realizing functions required for a screen by an optical device composed of only one sheet and free from fine particles and to provide a projection system using the diffusion film. ; SOLUTION: The diffusion film 3 is a single film for diffusing and emitting an incident light, realizes the diffusion by only the surface shape, and has nearly constant top hat diffusion characteristics without depending on the incident angle.