| 摘要 |
PROBLEM TO BE SOLVED: To provide a tilt angle detecting device which can accurately detect a tilt angle without using a tilt detecting mechanism and a tilt angle detecting method. SOLUTION: This device has a first push-pull signal generating means generating difference in light receiving signals of a photodetector corresponding to two light receiving planes in one of light receiving regions sectioned in a track tangential line direction out of four light receiving planes of a quadripartite photodetector as the first push-pull signal. Further, the device is provided with a second push-pull signal generating means generating difference in light receiving signals of a photodetector corresponding to two light receiving planes in the other light receiving region sectioned in a track tangential line direction out of four light receiving planes as the first push-pull signal, and a tilt signal generating means generating the tilt signal indicating a tilt angle formed by the normal line at the irradiation position of a laser beam of a recording plane of an optical recording medium and the optical axis direction of the laser beam in accordance with the difference of the amplitude of the first push-pull signal and the amplitude of the second push-pull signal. COPYRIGHT: (C)2004,JPO
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