| 摘要 |
PROBLEM TO BE SOLVED: To obtain a film capable of widening visual field angle without degrading front luminance by arranging plural projecting parts or recessed parts having curved surfaces via a plane parts on a base material and specifying the double refractive phase difference of light to a specific value or above in both of the intra-surface direction and the thickness direction. SOLUTION: The plural projecting parts 1a or recessed parts having the curved surfaces are arranged via the plane parts (a) on the base material and the double refractive phase difference of light is specified to <=60μm in both of the intra-surface direction and the thickness direction. The projecting parts 1a or recessed parts are formed into a circular shape of 0 to 100μm in the radius of section and the plane parts (a) formed to have a length of 20 to 100μm. The sections of the projecting parts 1a or recessed parts are rectangular and these rectangular shapes are formed to have a long side or shot side of 20 to 100μm. The materials used for this visual field widening film includes materials which are translucent or transparent materials retaining the parallel ray transmittance in a normal direction without degradation and have a refractive index of >=1.0; for example, polycarbonate, polymethyl methacrylate, etc. |
