| 摘要 |
PURPOSE:To exactly erase pre-recorded information and to record new information at the same time by modulating a second optical beam by superimposing a signal generated by delaying a signal read out by a first optical beam on a signal for recording new information. CONSTITUTION:The first optical beam 9 is radiated to form a spot in a position ahead of the second optical beam 10 in the moving-direction of a medium 11, and reads information (magnetization) recorded before the recording or erasing by the second beam. A signal read by the first beam 9 is delayed for a time necessary for the medium 11 to move between the beams, then the second beam 10 is modulated, so that the prerecorded information (magnetization) can accurately be erased. Also, the signal generated by delaying the signal read by the first beam and a signal for the recording of new information are added up with each other to modulate the second optical beam. As a result, the erasing of the past information and the recording of new information, i.e., an overwrite action can be attained in one time processing. |
