TRANSPARENT POLYCRYSTAL SPINEL SUBSTRATE, METHOD FOR PRODUCING THE SAME, AND OPTICAL PRODUCT USING THE SUBSTRATE

摘要

PPROBLEM TO BE SOLVED: To provide a transparent polycrystal spinel substrate in which the blurring and light/shade in an image do not occur even if used as an optical product, to provide a method for producing the same, and to provide a liquid crystal projector and a rear projection television set using the transparent polycrystal spinel substrate. PSOLUTION: The transparent polycrystal spinel substrate has a transmittance of 0.005% in a crossed Nicol system at the thickness of 1 mm and at the wavelength of 450 nm. The method for producing a transparent polycrystal spinel substrate comprises: a stage where spinel powder is prepared; a stage where the spinel powder is compacted so as to produce a spinel compacted body; a stage where the spinel compacted body is sintered so as to produce a spinel sintered compact; and a stage where the spinel sintered compact is subjected to HIP (hot isostatic pressing) so as to produce a spinel polycrystal. The liquid crystal projector or the rear projection television set use the substrate. PCOPYRIGHT: (C)2009,JPO&INPIT