| 摘要 |
PURPOSE:To obtain an optical head having high responsiveness of frequency and a wide tracking range by providing the monolithic movable part that can have servo actions in both focusing and tracking directions after fixing an image forming lens and a movable reflector to each other and also setting a fixed reflector to an optical path formed between the lens and the reflector. CONSTITUTION:When a monolithic movable part 5 is moved to the right by a tracking servo, the incident point has no change on a movable reflector 2 since the shift of the part 5 is in parallel with the tracking direction, i.e., an incident luminous flux 1. The reflected light 1' moves to the right together with the part 5 and the incident point to a fixed reflector 4 moves to the right. While an image forming lens 3 is also shifted to the right by an amount equal to the shift of said incident point. As a result, the reflected light 1'' received from the reflector 4 is never shifted from the axis of the lens 3. Then the part 5 moves up in the direction rectangular to the flux 1. In such a case, the incident point of the flux 1 moves on the reflector 2. However, both the light 1' and the incident point on the reflector 4 have no shift with the light 1'' kept coincident with the axis of the lens 3. Thus no effect is given to the tracking servo.
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