Patent ID: 8477272
Filing Date: 2013-07-02
Classification: G02B,G03B,G09G,G11B,H04N

Abstract:
1. A quarter wave plate that is a crystal plate made of an inorganic material having birefringence and optical rotatory power and has an optical axis, comprising: an incident surface positioned on one surface of the crystal plate; and an emitting surface positioned on another surface, opposed to the incident surface, of the crystal plate, wherein linearly-polarized light incident from the incident surface is converted into circularly-polarized light so as to be emitted from the emitting surface, circularly-polarized light incident from the incident surface is converted into linearly-polarized light so as to be emitted from the emitting surface, an angle φ formed by a normal line on the incident surface and the optical axis is set in a range of 0°<φ<90°, an optical axis azimuth angle θ formed by an optical axis projection line, the optical axis projection line being formed by projecting the optical axis on the incident surface, and a polarization plane of the linearly-polarized light is set in one of a range of 0°<θ<90° under θ≠45° and a range of 90°<θ<180° under θ≠135°, and the crystal plate is made of quartz crystal, wherein