OPTICAL ELEMENT

摘要

PURPOSE:To prevent the degradation in the definition with age occurring by flowability by binding the unit which reversibly generates a structural change by light onto the surface of a hydrolyzed poly(vinyl acetate) film provided on a transparent substrate and providing a liquid crystal layer via this film. CONSTITUTION:This optical element generates a change in the orientation of the liquid crystal layer by the effect of the poly(vinyl acetate) film combined with the residual group which reversibly generates the structural change by light on the surface layer and reversibly changes the transmittance of light by utilizing this change. Namely, the film 2 combined with the unit which reversibly generates the structural change by light by an acetal or ester bond is formed on the surface of the hydrolyzed poly(vinyl acetate) film provided on the transparent substrate 1. The liquid crystals of the optical element having the sandwich structure interposed with the liquid crystal layer between two sheets of the substrates formed in such a manner are regularly arranged perpendicular to the substrate surface but the liquid crystals of the part irradiated with light has the arrangement parallel with the surfaces when the element is irradiated with light. The transmittance of light is thereby changed.