| 摘要 |
PROBLEM TO BE SOLVED: To provide a deflecting method having the intensity distribution of a laser beam, being not changed so much, on a magnetooptical disk at the time of fine adjust able tracking by deflection by means of a deflecting means and having little lowering of coupling efficiency to an objective optical system in an optical information recording /reproducing head constituted so as to perform finely adjustable tracking by finely adjusting the incident angle of a laser beam on an objective optical system, provided in the tip part of a coarse moving carriage moving in the direction crossing a track of a magnetooptical disk, by means of a deflecting means such as a galvano-mirror. SOLUTION: After a light beam transmitted from a laser beam source is made to into parallel light beam, the beam is made incident on an objective optical system through a galvano-mirror (deflection mirror) 26, converged on an optical disk 2 and coarse adjustable tracking is performed by changing a distance between the galvano- mirror 26 and the objective optical system. In this case, by representing the distance between the galvano-mirror 26 and the objective optical system by L and the turning angle of the galvano-mirror 26 by θ, the incident laser beam is deflected so that its center of reflection is moved by the moving amount: h=Ltan(2θ) in the incident direction of the parallel light beam according to the rotation of the galvano-mirror 26. |
