| 摘要 |
PURPOSE:To check accurately an abnormality of a recording power by supplying a DC or a low frequency pulsative drive current to a semiconductor laser during the recording period of a prescribed power check section so as to use a monitor circuit obtaining a level in response to the power of a laser beam in common. CONSTITUTION:A gate signal (e) incoming to an input terminal 30 rises just after a preformat section PF of the n-th sector and falls before the end of a data part as a pulse. Further, the sector is provided with a power check part PC at a field different from a data part D. This is provided because a different field is required from the data field since pits are formed on the thin film of an optical disc when a laser beam is irradiated on the optical disc for checking the power of the laser beam at recording. Thus, the power check part PC is a dummy field for recording power check. |
