| 摘要 |
PROBLEM TO BE SOLVED: To enable a tilt servo at a small sized pickup device. SOLUTION: Lights from a laser diode 26 become parallel lights at a collimator lens 34 and are reflected in the direction of an objective lens 40 by a reflective mirror 38. The parallel lights pass through a through hole 44 set up in an objective lens holder 42 are reflected by a disk, and the reflected light is entered in a light receiving sensor 60 through the collimator lens, light polarization splitter 30, and prisms 52, 54. The parallel lights reflected at the reflective mirror are reflected by a mirror 50 integrated with an objective lens holder, and are entered into the light receiving center 60 through the collimator lenses, the polarization splitter, and prisms 52, 56. From an output signal of a split light receiving sensor of the light receiving sensor 60, a disk tilt and/or objective lens tilt is detected.
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