| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup device capable of reliably performing servo control of the position of an optical spot formed on an optical recording medium. SOLUTION: The light receiving face 8a of a light receiving element 8 in an optical pickup device 1 is such that a circular light receiving face E for reading information is formed in the center and, in a fashion surrounding this face E, four identically-shaped light receiving faces A, B, C, D are formed for servo error detection. The size of the light receiving face E for reading information is set so as to be included in the effective projection part 11 of an optical spot which is formed on the light receiving face 8a in a focused state, allowing light receiving to be observed in the light receiving face A or D for servo error detection even in the focused state. As a result, in front of and behind the focused point position, servo error signals such as tracking error signals can be surely formed, on the basis of the light receiving quantity on the light receiving face for servo error detection; therefore, the servo control of the optical spot position can be reliably performed.
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