PHASE-TYPE DIFFRACTION DEVICE, MANUFACTURING METHOD THEREOF AND IMAGE PICK-UP APPARATUS

摘要

A phase-type diffraction device is provided, which includes a substrate (2) having a front surface and a rear surface and a solidified liquid crystal layer (3) formed on the front surface of the transparent substrate and constituted by a continuous film containing at least a liquid crystal compound. The solidified liquid crystal layer is constituted by first, second and third regions (3a, 3i, 3m) arranged periodically, the third region being interposed between the first region and the second region. The first region is optically anisotropic and the second region is optically isotropic, the third region is not optically isotropic, a degree of orientation of mesogens of the liquid crystal compound being lower than that of the first region. An in-plane average refractive index n i of the second region is different from an in-plane average refractive index n a of the first region and the third region has a value between n i and n a as an in-plane average refractive index n m .