| 摘要 |
PROBLEM TO BE SOLVED: To make an optical pickup small size and light weight and also high reliable by casting a light beam made to enter a prism from a branching point of an optical path to the light receiving element from a surface formed with a semitransmission film. SOLUTION: The light emitting and receiving elements 21 and the optical pickup 20 using them are formed integrally with the prism 28 by its double refeaction material. As a result, return light from a magnetooptical disk MO is incident on the prism 28 and is splitted, and also these light beams reflected by the semitransmission film 31 formed on the bottom are reflected by the upper surface of the prism 28 based on a difference of refractive index between the double refractive material constituting the prism 28 and the open air. Then, the beams are guided to the bottom surface of the prism 28 and are incident upon 2nd and 3rd photodetectors. Therefore, it is not necessary to provide a total reflection film on the upper surface of the prism 28, and hence miniaturization and reduction in weight are feasible. |
