| 摘要 |
<p>The object of the invention is to provide a variable light transmission device and projection display apparatus in which vibrations and noises are not generated, which is superior in light blocking property to a variable aperture using polymer-dispersed liquid crystal, and in which a color change of a projected image can be reduced as compared with a conventional variable aperture using liquid crystal. The invention relates to a variable light transmission device wherein the device has: a pair of transparent substrates which are placed in parallel to each other; a multi-layer grating member which is disposed on one of opposing substrate surfaces of the pair of transparent substrates, and in which transparent members having a multi-layer structure are periodically placed so as to form a diffraction grating, and the diffraction grating has a convex and concave section shape; liquid crystal which is interposed between the pair of transparent substrates to bury the multi-layer grating member; and transparent electrodes for applying an electric field to the liquid crystal, and the transparent members possessed by the multi-layer grating member have a multi-layer structure in which plural dielectric thin films having different refractive indexes are periodically stacked, and also to a projection display apparatus having the variable light transmission device.</p> |
