| 摘要 |
PURPOSE:To remove a beam shifting with a good follow-up characteristic by interlocking and controlling an actuator and a mirror so that the light shaft of an optical beam deflected by the mirror can always pass the focus at the rear side of the objective lens. CONSTITUTION:An actuator 300 and an actuator 200 are interlocked and the light axis always passes through an objective lens rear focus (P0 and P1). Namely, when an objective lens 2 is shifted from an L1 to an L2, the focus is shifted from 70 to 70', and at such a time, so that the light axis can pass a rear side focus P1, the shifting quantity and the deflecting quantity of the actuator 300 and the actuator 200 are interlocked and controlled. by executing the control, an optical beam always passes the rear side focus of the objective lens 2, the optical beam always returns to the same optical path, and then, the beam shifting is removed. Further, since it is not necessary to the rotating center of the mirror at the rear side focus surface, the mirror can be made small and light, and a response characteristic is also improved.
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