| 摘要 |
PURPOSE:To widen the laser light detecting surface of an external PIN photodiode by preventing the laser light from separating out of the laser light detecting surface and to obtain a recording/reproducing device provided with an automatic controlling circuit for a laser light power having a circuit for detecting the deviation from the center. CONSTITUTION:In a device using an external PD 10, the device provides a detecting means in which the size of the laser light detecting surface of an external PIN photodiode 10 is widen to 12X12mm and the laser light detecting surface is quadri-sected while detecting on what position the laser light is received. Since the laser light detecting surface is widen sixteen times of that of a conventional PD, the spot position of the laser light from a laser diode 1 is hardly separated from the laser light detecting surface of the external PIN photodiode 10, the deviated position is recognized even when the light gets out of the center and the spot position is easily adjusted. |
