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Optical recording and reproducing apparatus having erasing function with controllable erasing beam
| Details |
Inventors: Satoh, Isao; Ichinose, Makoto; Fukushima, Yoshihisa; Kuroki, Yuzuru; Takagi, Yuuji;
Assignee: Matsushita Electric Industrial Co., Ltd. (Osaka, JP)
Primary Examiner: Psitos; Aristotelis M.
Assistant Examiner:
Attorney, Agent or Firm: Stevens, Davis, Miller & Mosher
A data recording and reproducing apparatus is disclosed in which an optical disc for recording, reproducing or erasing data is radiated with an erasing light beam and a recording-reproducing light beam sequentially to record or reproduce the data with the recording-reproducing light beam and erase the data with the erasing light beam. In rewriting the data, the erasing light beam is radiated in advance of the recording-reproducing light beam on a data section of the disc, and the old data is erased by temperature increase and annealing by the erasing light beam, while new data is recorded by temperature increase and quenching with the recording-reproducing light beam set to the recording light intensity. After recording the new data, the light intensity of the erasing light beam is gradually decreased and turned off. In rewriting the sector data, the erasing light beam is radiated on the data section in advance of the recording-reproducing light beam, and by the temperature increase and annealing with the erasing light beam, the old data is erased, while new data is recorded by temperature increase and quenching with the recording-reproducing light beam set to the recording light intensity. After recording the new data, the light intensity of the erasing light beam is turned off after being modulated for a predetermined time. By doing so, the process of the temperature and quenching is eliminated which otherwise might be required at the time of turning off the erasing light beam, thereby preventing occurrence of a recording trace and a defect of the recording medium by a thermal shock. |
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DETAILED DESCRIPTION In view of the aforementioned points, the object of the present invention is to provide a data recording and reproducing apparatus which is free of a recording trace or a defect by the erasing light beam in the rear gap of the data section of the sector.
According to the present invention, there is provided a data recording and reproducing apparatus comprising means for radiating an erasing light beam and a recording-reproducing light beam sequentially on an optical disc for recording and reproducing or erasing the data by sector, means for recording or reproducing the data with a recording-reproducing light beam, means for erasing the data with the erasing light beam, and means for reducing and controlling the light intensity of the erasing light beam with time.
According to another aspect of the present invention, there is provided a data recording and reproducing apparatus comprising means for radiating an erasing light beam and a recording-reproducing light beam sequentially on an optical disc for recording and reproducing or erasing the data by sector, means for recording or reproducing data with the recording-reproducing light beam, means for erasing the data with the erasing light beam, and means for modulating and controlling the light intensity of the erasing light beam.
According to the present invention, by use of the aforementioned configuration, in the process of rewriting data in the sector, the erasing light beam is radiated on the data section in advance of the recording-reproducing light beam, and the temperature increase followed by annealing is effected by the erasing light beam thereby to erase the old data, so that the temperature increase followed by quenching is effected with the recording-reproducing light beam set at a recording light intensity thereby to record new data.
At the end of the recording of the new data, the light intensity of the erasing light beam is modulated and turned off, and in this manner, the recording trace which may be caused at the time of turning off the erasing light eliminated on one hand, and the DC component of the recording trace occurred is reduced on the other hand, while at the same time reducing the thermal shock thereby to prevent a defect
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