| 摘要 |
PURPOSE: To reduce the leakage of a control signal to an information signal by detecting the control signal for automatic focusing and automatic tracking by means of a first photodetector and detecting the information signal recorded in an information carrier. CONSTITUTION: A reflected light beam from a recording surface is made incident on an optical system 7 through an objective lens 5 and a polarizing beam splitter 4. The optical system 7 diffracts a proper light quantity among the reflected light beam, introduces it to a photodetector 9 and detects a tracking error signal and focusing error signal. The rest of the reflected beam is transmitted though the optical element 7 and reaches another photodetector 30 through a detector 28 and a condenser lens 29. Consequently, the mutual leakage among the tracking error signal, the focusing error signal and the information signal is reduced. In this case, by composing a photodetector for detecting the tracking error signal and the focusing error signal and a photodetector for detecting the information signal independently, the arithmetic processing of the detected signal is facilitated. |
