| 摘要 |
PURPOSE:To improve specially the S/N of an optical signal obtained from a recording medium by providing an optical system to have a beam splitter in which one end plane interposed among the light source, the recording media and the reading means is formed so as to make a special angle specified beforehand. CONSTITUTION:A beam splitter 14 is formed so that one edge surface can form the special angle specified beforehand. From a laser device 11 to a beam splitter 14, the remaining laser beam, in which the laser beam made incident in the B2 direction of an arrow will not transmit, is reflected in the B3 direction of an arrow and made incident on an edge surface 27 by an incident angle thetab which is a Brewster angle. Consequently, the laser beam, which is a P polarized light, is all transmitted as shown in the arrow B7, the reflecting light in the direction of an arrow B3 is further reflected at the edge surface 27 and the reduction of S/N of the signal read can be prevented. |
