| 摘要 |
PURPOSE:To improve the S/N of a reproduction signal by irradiating a linearly polarized light beam to detect the change of the polarizing state of the light beam together with the reflection factor of a recording medium or the change of the transmittance of the beam and then reading the recorded information. CONSTITUTION:The laser beam oscillated by a laser oscillator 11 is turned into a linearly polarized beam through a polarizer 12 and forms a spot on a recording medium 17 through a collimator lens 13, a beam splitter 14, a galvano-mirror 15 and an objective lens 16 respectively. The light reflected by the medium 17 receives the modulation of intensity by the change of the reflection factor of a recorded bit as well as a change of its polarizing state between the recorded and unrecorded parts. Such reflected light is led to a photodetecting element 20 via the lens 16, the mirror 15, the splitter 14 and a condenser lens 18. Thus the change of the reflection factor of a recording medium is detected together with the change of the polarizing state. |
