发明公开
EP0773538A3 Objective lens driving apparatus 失效
AntriebsvorrichtungfürObjektivlinse

Objective lens driving apparatus
摘要:
A lens holder (75) is provided with objective lenses (34, 35) of different types. Rotating the lens holder (75) causes one of the objective lenses (34, 35) to be placed in the optical path of the laser beam. Near one objective lens (35), there is provided a reflecting element (92) that reflects part of the laser beam directed to the objective lens (35). When the objective lens (35) is put in the optical path, the beam from the reflecting element (92) is sensed by a sensor. From the sensing result, it is judged that a specific type of objective lens (35) is in the optical path. Accordingly, there is provided an objective lens driving apparatus that includes at least two objective lenses with different numerical apertures according to optical information recording mediums complying with different standards, is capable of switching between the objective lenses according to the optical information recording medium to be used, and further has a simple structure capable of identifying the type of the objective lens selected by switching.
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