Brightness enhancing film and film based diffuser for improved illumination uniformity of displays

An optical device, comprising:

• a first film having a first side and a second side and a diffuse scattering optical density between 0.5 and 3;
• and
• a second film disposed proximate the first side of the first film with at least one free light diverting surface that diverts light transmitted through the first film;
• wherein the first fraction is characterized by a half angle of diffusion of s1 and the second fraction is characterized by a half angle of diffusion of s2, the ratio s1/s2 being greater than 3.

An optical device, comprising:

• a light diffusing means for diffusing light by forming a first broadly diffuse fraction and a second narrowly diffuse fraction when illuminated by input light;
• and
• a first light diverting means for diverting at least a portion of the light transmitted through the light diffusing means;
• wherein the first fraction is characterized by a half angle of diffusion of s1 and the second fraction is characterized by a half angle of diffusion of s2, the ratio s1/s2 being greater than 3.