| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an optical position detector which can always be set to make high-accuracy optical position detection by correcting and adjusting erroneous detecting operations caused by the deviation between the optical axis of astigmatic optical system and the central optical axis of a plurality of divided photodiodes. SOLUTION: An optical position detector is always set to make high-accuracy optical position detection by making a calculated focus error signal FE always zero by correcting and adjusting the deviation between the central optical axis of a quadripartite photodiode 26A and the optical axis of an astigmatic optical system caused by a mounting deviation or the deviation between the optical axis of the beam of the optical system and the central optical axis of the photodiode 26A caused by the tracking control deviation of an optical disk by respectively impressing optimum reverse bias voltages Vra-Vrd upon the divided photodiodes A-D of the photodiode 26A and correcting the mounting deviation or tracking control deviation at the position where the information recording surface of a photodiode coincides with the focal plane of an objective lens. Therefore, focus control can be performed with accuracy.</p> |
