| 摘要 |
PROBLEM TO BE SOLVED: To form a transparent substrate with high light availability with plastic material by forming a transparent shield film inactive for a liquid crystal and preventing the liquid crystal from penetrating onto the surface of a rugged part. SOLUTION: When a P wave is emitted from a semiconductor laser L, the P wave passes through the liquid crystal 3 and a glass substrate 5 as it is, and is circularly polarized by a phase difference film 6, and goes out from an optical head device to irradiate an optical disk being a recording medium through an aspherical lens not shown in the figure. The circularly polarized is reflected by the optical disk, and is made incident on the optical disk device again, and becomes an S wave by the phase difference film, and is diffracted in two directions by an optical anisotropic diffraction grating consisting of the liquid crystal 3 and the rugged part of the transparent substrate 1 to be detected by respective detectors D1, D2, and the information is read. |
