Patent ID: 8703252

Claim:
A multi-layer uniaxially stretched film comprising 251 or more alternating layers which consist of first layers and second layers, wherein 1) the first layers are layers having a thickness of 0.01 to 0.5 μm and containing a polyester comprising a dicarboxylic acid component and a diol component: (i) the dicarboxylic acid component contains 7 to 50 mol % of a component represented by the following formula (A) and 50 to 93 mol % of a component represented by the following formula (B): in the above formula (A), R A is an alkylene group having 2 to 10 carbon atoms; in the above formula (B), R B is a phenylene group or naphthalenediyl group; and (ii) the diol component contains 90 to 100 mol % of a component represented by the following formula (C): —O—R C —O— (C) in the above formula (C), R C is an alkylene group having 2 to 10 carbon atoms; and the second layers are layers having a thickness of 0.01 to 0.5 μm and containing a thermoplastic resin having an average refractive index of 1.50 to 1.60 and differences in refractive index among a unidirectional stretching direction (X direction), a direction (Y direction) orthogonal to the uniaxial stretching direction within the film plane and a film thickness direction (Z direction) of 0.05 or less before and after stretching; 2) the average reflectances at a wavelength of 400 to 800 nm for polarization incident at angles of 0° and 50° of a polarization component parallel to the incidence plane including the X direction with the film plane as a reflection plane are 90% or more; 3) the average reflectances at a wavelength of 400 to 800 nm for polarization incident at angles of 0° and 50° of a polarization component perpendicular to the incidence plane including the X direction with the film plane as a reflection plane are 15% or less; 4) the ratio of the thickness of the maximum layer to the thickness of the minimum layer in the first layers and the second layers is 2.0 to 5.0 respectively; and 5) the difference in refractive index in the X direction between the first layers and the second layers is 0.10 to 0.45.