| 摘要 |
PURPOSE:To attain a recording/reproducing section free from maintenance by mounting a minimum number of a recording/reproduction laser device, a rotary polygon mirror scanning a laser light onto a magnetic tape and a photodetector and recording/reproducing a video signal through the laser light to eliminate the deterioration of the service life due to the wear of a magnetic head. CONSTITUTION:A video signal is processed by modulating a magnetic field made by a magnetic field generating coil 24 fitted to a tape guide 22. Since the tape guide 22 is made of a nonmagnetic substance, the magnetic field reaches a tape and the vicinity of a magnetic field generation coil 24 is arranged unidirectionally. In scanning the laser light to it, the video signal is recorded. The laser light 20 is subject to linear polarization by a polarizer 25, the light is converged on the tape 1 via the rotary polygon mirror 21 so as to detect the rotary angle of the polarized plane of the reflected at reproduction. The optical path of the reflected light whose polarized plane is turned in response to the state of magnetization is changed by a half mirror 26 and enters a photodetector 28. Since the strength of the transmitted light changes according to the rotary angle of the polarized plane, it is converted into an electric signal by the photodetector 29. |
