| 摘要 |
PURPOSE:To decrease the access time by providing a detecting means for detecting the opening and closing states of a shutter and using a signal from the detecting means to start supply of a cutting signal. CONSTITUTION:A position of a cutting head 9 of an optical master disc 12 in the radial direction is retrieved at first and when the head comes to a prede termined position, a shutter drive circuit 8 is driven and the drive of a laser 1 is started. A shutter 7, however, is not opened at the same time. When the shutter 7 is opened, reflected light from the disc 12 is irradiated on a detector 21, and when an output of the detector 21 reaches a predetermined value, a cutting signal source drive circuit 22 is actuated and a cutting signal is fed from a cutting signal source 5 to an optical modulator 4. Thus, a track number and a sector number starting from 0-track and 0-sector are recorded on a pre scribed position of the disc 12.
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