Patent ID: 8085294

Claim:
A stereoscopic image display apparatus comprising: a plane display device including a plurality of pixels arranged in a display surface; a lens array provided in front of the display surface to distribute light rays from the pixels to predetermined angles, the lens array having a plurality of lenses arranged in a first direction; a variable polarizer provided between the plane display device and the lens array to polarize light rays from the pixels; and a double refraction prism array provided on an opposite side of the lens array from the plane display device, the double refraction prism array including a plurality of double refraction prisms each having a ridge in a second direction perpendicular to the first direction and arranged in the first direction with a pitch which is substantially twice a lens pitch in the lens array, each of the double refraction prisms having double refraction in which a refractive index in the second direction is different from a refractive index in the first direction, wherein the double refraction prism array comprises: a prism having a flat surface on an opposite side from the lens array and a surface on the lens array side provided with a groove which extends in the second direction and takes a triangular prism; and a double refraction substance inserted into the groove of the prism, and wherein when r is a curvature radius of a bottom part of a groove of the double refraction prism, t_top_prism is a distance between a surface of the prism of the lens array side and a vertex of the groove taking a shape of a triangular prism, t_lens is a thickness of a lens in the lens array, n is a refractive index of the prism, and θ is a half of a viewing angle, following expression is satisfied: r= 5×( t _top_prism+ t _lens)×tan(arcsin(sin(θ)/ n )).