| 摘要 |
PURPOSE:To simplify a detecting means for detecting respective errors by allowing a photometry sensor to house a photodiode for detecting a focus error, a photodiode for detecting a tracking error and a means to reflect a part of an incident light towards the photodiode for detecting the tracking error. CONSTITUTION:On the optical axis of a detected light 8, a converging lens 6 and a photometry sensor 7 are coaxially arranged, respectively. To a substrate 9 of the photometry sensor 7, a photodiode 13 for detecting a focus error positioned in the optical path of the detected light 8 and a photodiode 14 for detecting a tracking error at a prescribed distance from it are integrally fixed so that respective light-receiving surfaces can be positioned on the same plane surface. To a prism body 15, the half of the detected light 8, whose direction is changed by a reflecting film 16, is converged to the central part of the photodiode 14 for detecting the tracking error. Thus, since the detection can be directly executed not through a reflecting means, the position adjustment of the reflecting means can be facilitated. |
