| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup device which is low in price, small in size, light in weight and high in reliability. SOLUTION: An aperture and a diffraction grating are formed on a first incidence and emission plane 3a of a prism 3 and a hologram is formed on a second incidence and emission plane 3b. The diameter of the light beams generated by a light beam generating section 2 is selected by the aperture and the beams are separated into three incident beams by the diffraction phenomenon of the diffraction grating. The incident light beams are reflected by a first inclined plane 3c, reflected by a second inclined plane 3d and reach the plane 3b. Then, the beams are converged by the diffraction phenomenon of the hologram and irradiate the surface of a recording medium 1 as irradiating beams. The beams reflected by the surface of the medium 1 are converged by the hologram, deflected by the plane 3d, reflected by the plane 3c and detected by a photodetecting section 4. |
