| 摘要 |
PURPOSE:To easily adjust the optical axis of a laser beam by arranging an optical modulator on an optical path from a laser beam source to an objective lens, providing a driving circuit in this optical modulator so as to change the amplitude and frequency of an ultrasonic wave and arranging a lens on the optical path before and behind the optical modulator. CONSTITUTION:On the respective optical paths splitting a beam, which is emitted from an Ar<+> laser 13 as the laser beam source, into two beams, optical modulators 14a and 14b are arranged to enable light quantity modulation, pulse modulation and wobble modulation. These respective optical modulators 14a and 14b are connected to driving circuits 15a and 15b to change the amplitude and frequency of the ultrasonic wave. On the other hand, lens 16a, 16b, 17a and 17b are arranged on the optical paths before and behind these optical modulators 14a and 14b. Thus, since only one modulator is provided in one exposing optical system, the optical axis of the laser beam can be easily and speedily adjusted. |
