| 摘要 |
PURPOSE:To attain the recording/reproduction of information from information recording media with different systems by detecting a returned light so as to obtain the 1st reproducing signal from a differential output, adding the detection outputs of returned lights having different optical paths to be detected to obtain the 2nd reproducing signal. CONSTITUTION:The light beam of a semiconductor laser 1 is reflected in a beam splitter 2 via a collimator lens 11 and a polarizer 12, collected by an objective lens 3 and irradiated to an information recording medium 4. The returned light from the medium 4 is transmitted through the splitter 2 with the interference by pits and the rotation of the polarized plane in respond to the magnetization direction by the Kerr effect and made incident in a differential optical system 5 via a 1/2 wavelength plate 51. The polarized beam splitter 52 of the optical system 5 transmits the P polarized component and reflects the S polarized light component, they are detected by photodetectors 56, 57 respectively and the detection signal is fed to a differential amplifier 58 and a summing amplifier 6. A reproducing signal by the magnetooptic effect in response to the polarized plane is obtained from the amplifier 58 and a reproducing signal in response to the light interference by pits is obtained from the amplifier 6. |
