| 摘要 |
PURPOSE:To reduce the noise of a laser diode and to perform a stable recording and reproducing by allowing an optical pickup to obtain an output signal based on both a p-polarized light and an s-polarized light. CONSTITUTION:In the case where a double refraction is not present in an optical disk, the components of an incident light being made incident on a second photodetector are the reflected light of the s-polarized light 70% and the reflected light of the p-polarized light 30%, and in total, the outgoing light of the laser diode is made incident on the photodetector by 100%. On the contrary, in the case where the phase difference of the double refraction of the optical disk is 60 deg., an incident light being made to incident on the second photodetector is 86% by adding the s-polarized light and the p-polarized light and the turned-back light quantity to the laser diode is 14%. An RF envelope display is shown is figure (c) to grasp visually the change of light quantities, the figure shows that the turned-back light quantity is smaller than that of a conventional device and the incident light quantity to the photodetector is increased. Thus, the S/N of the diode is improved and the stable recording and reproducing is performed. |
