| 摘要 |
PURPOSE:To efficiently convert exit light from a laser light source into waveguide light by using a deflecting means consisting of a liquid crystal layer and a 1/4 wavelength plate. CONSTITUTION:The linearly polarized light in directions 23A and 23B from the laser light source through a condensing lens becomes circularly polarized light 24 in polarization directions 24A-24D by means of the 1/4 wavelength plate 21 which forms the polarizer of an optical head with the liquid crystal layer 22 and where an optical axis makes 45 deg. with the polarization directions 24A and 24B. The polarized light 24 becomes polarized light 25 by being efficiently converted into the linearly polarized light having much vibration component in the tangential directions 25A-25D of a concentric circle or elliptically polarized light having high vibration component in a radiation direction by the right angle TN liquid crystal layer 22 with a right angle constitution in all the areas of necessary parameters having one side oriented in a concentric circle direction 27 with center at a central point O1 and having the other side oriented in the radiation direction 26 with center at the central point O1, and then passes through the grating coupler of a waveguide, thereby efficiently irradiating an optical disk with the waveguide light. |
