| 摘要 |
PURPOSE:To improve the carrier noise (CN) ratio by using a phase difference correction means so as to correct an ununiform phase difference caused when a laser beam is made incident and reflected on/from an optical information recording medium. CONSTITUTION:The phase correction means is provided in an optical path of a laser beam radiated from the optical information recording medium 1. The phase difference correction means 9 is controlled by a control means so as to cancel the phase difference caused in the optical information recording medium 1. Thus, the ununiform phase difference caused when a laser beam is made incident and reflected on/from the optical information recording medium is corrected and the laser light led to the optical information recording medium 1 and photodetectors 15, 19a, 19b is made to be nearly a linearly polarized light thereby maximizing the reproduced signal amplitude. Moreover, the carrier noise (CN) ratio is improved. |
