| 摘要 |
PROBLEM TO BE SOLVED: To exactly enable fine adjustable tracking by using a device for finely adjusting the incident angle of a laser beam on the objective optical system of a magnetooptical disk by means of a deflecting means such as a galvano-mirror. SOLUTION: In this optical information recording/reproducing head, a light beam transmitted from a laser beam source is made to be a parallel beam, thereafter, it is made incident on an objective optical system through a deflecting means 26 and converged on an optical disk. An afocal relay optical system composed of a relay lens group and an imaging lens group is arranged between the deflecting means and the objective optical system, the vicinity of the deflection plane of the deflecting means and the principal plane position of the objective optical system are made to be almost a conjugate relation, a transmissive coating for a parallel light beam is performed in a first area of the incident plane 261 of a wedge-like prism 260 consisting a deflection member, a reflection coating for a transmissive light beam is performed on the wedge plane of the wedge-like prism through it, an antireflection coating, transmitting a reflected light beam by the reflection coating from a second area being not overlapped on the first area of the incident plane, is performed on the second area, the transmitted laser beam from the second area is detected by a photodetector 50 and the turning amount of the incident being the deflection plane of the deflecting means is detected. |
