| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup device which can output a signal including the information necessary for the positional control, etc., of the optical pickup device itself and an objective lens accurately and stably without increasing the size and cost. <P>SOLUTION: Luminous flux emitted from a light source are focused on the recording surface of an information recording medium 15 through an optical element 53 and the objective lens 60, and return luminous flux reflected on the recording surface and passed through the objective lens and optical element 53 is received by a photodetector 59. For instance, when the optical phase difference is imparted to the luminous flux transmitting through the substrate of the information recording medium, a specified voltage is applied to the optical element so that the phase difference having the polarity opposite to that of the optical phase difference imparted to the luminous flux transmitting through the substrate is imparted to the luminous flux transmitting through the element. Thus, the return luminous flux with less errors in the optical phase difference is obtained, and for instance, even when the return luminous flux is branched through a polarizing branch optical element, the signal level and S/N ratio of the signal outputted from the photodetector are prevented from deteriorating. <P>COPYRIGHT: (C)2004,JPO |
