| 摘要 |
PURPOSE:To improve the efficiency of a data processing at the time of rewriting and postscribing data by converging two laser beams with different wavelength on a recording medium by an objective lens, and separating and detecting transmission light and reflected light by an optical BPF. CONSTITUTION:Lasers 1 and 2 are shifted corresponding to a quantity of chromatic aberration, and are arranged in a metallic can case 3. The emission rays of light of the lasers 1 and 2 are reflected on a mirror 6 after passing a beam splitter 5, and converged on the recording plane of a magneto-optical disk 8. Out of the light transmitting the disk 8, only that of the laser 2 is made incident on an analyzer 10 by the BPF9, then, a data signal can be obtained. Meanwhile, the reflected light from the disk 8 is reflected on the splitter 5, and only the laser 1 passes the BPF12, then, a tracking servo signal and a focusing servo signal can be obtained via a beam splitter 13. Since the spot of the laser 2 is converged before the laser 1, it can be reproduced immediately after recording in a second time after erasure. Therefore, rewrite can be completed in two times of operations, and thereby, the efficiency of the data processing can be improved. |
