| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an interference type optical pickup which easily adjusts an optical path difference of two lights, and ensures a high signal amplification effect and are suitable for size reduction of an optical system, and to provide a method for detecting optical information and an optical information recording and reproducing device. <P>SOLUTION: A signal light 205 reflected from an optical disk 209 and a reference light 206 branched from the same light source and guided into detectors without being projected onto the optical disk are caused to interfere with each other on detectors 701-704. Detector outputs in four interference states in which phase relationships between the reference light and the signal light are different from each other by 90 degrees are simultaneously obtained and calculated. Accordingly, a readout signal RF that is always stable and amplified with high quality is obtained even when an optical path changes due to disk undulations. The four detector outputs are simultaneously obtained by use of four quadrant photo detectors, and are calculated, to thereby also obtain a servo signal. <P>COPYRIGHT: (C)2010,JPO&INPIT |
