| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup device capable of outputting signals including information on inclination of an information recording medium with respect to an objective lens with high accuracy without incurring the upsizing of the device and the increase of the cost of the device. <P>SOLUTION: A part of the luminous flux emitted from a light source is diffracted at least at one of diffraction parts 53 of an objective lens 60 to irradiate the recording surface of an information recording medium 15. A second return luminous flux which is reflected on the recording surface and is passed through the diffraction parts is received by a second photodetector 61. When a bisected light receiving element is used as the second photodetector, information concerning to the inclination of the recording medium is to be included in the difference signal of output signals from respective light receiving elements and a light source for detecting inclination is unnecessary. Moreover, since luminous flux of comparatively high intensity can be utilized in the device, the signal level and the signal to noise ratio in the output signal from each light receiving element can made high. <P>COPYRIGHT: (C)2004,JPO |
