| 摘要 |
PROBLEM TO BE SOLVED: To realize a monitor mechanism having a simple structure in an optical pickup device which records or reproduces information to or from different information recording media by using beams of different wavelengths. SOLUTION: The laser beams h1 and h2 of different wavelengths emitted from the semiconductor lasers 2a and 3 are made incident on an optical path multiplexing prism 13 having a semitransparent film HM, and the light intensity of the beams h1 and h2 are detected by a photoelectric transducer 15 provided on the optical paths that are turned into a single path by the prism 13. Then the light intensity of both lasers 2a and 3 is subjected to the APC control on the basis of the detected light intensity of both beams h1 and h2. Thus, the intensity is properly controlled about the beam h1 that is transmitted through the prism 13 and cast on an information recording medium and the beam h2 that is reflected on the prism 13 and cast on the information recording medium respectively. |
