Patent ID: 8747966

Claim:
An optical element comprising: a liquid crystal layer having a difference between in-plane refractive index in a slow axis direction and in-plane refractive index in a fast axis direction of 0.05 to 0.2 and a thickness of 0.5 μm to 2.0 μm, and satisfies the following Equation 1; a first adhesive layer attached to one surface of the liquid crystal layer and having a glass transition temperature of 85° C. or higher; a polarizer attached to one surface of the first adhesive layer; a second adhesive layer attached to one surface of the polarizer; and a pressure-sensitive adhesive layer attached to one surface of the second adhesive layer: X<8% Equation 1 wherein X represents a percentage of a variation in a phase difference value of the liquid crystal layer obtained after keeping the optical element at 80° C. for 100 hours, relative to the initial phase difference value of the liquid crystal layer of the optical element.