POSITIONING DEVICE OF OPTICAL SPOT

摘要

PURPOSE:To control stable spot positioning by arranging an optical system for rotating the polarizing direction of light from a galvanomirror by 90 deg. between the galvanomirror and a focus optical system. CONSTITUTION:The rotary shaft of the galvanomirror 10 is fixed in parallel with the moving direction 100 of a crude positioning means 4. An optical beam from a semiconductor laser 8 is bent by a proper optical system so that an incident surface formed by an incident light beam on the galvanomirror 10 and the galvanomirror 10 is arranged rectangularly to the moving direction 100 of the crude positioning means 4. The optical beam polarized by the galvanomirror 10 is reflected by a mirror 16 having 45 deg. inclination from the incident surface, and further reflected by a mirror 18 having 45 deg. inclination from the incident angle formed by the incident light of the mirror 16 and the mirror 16 and projected on the surface of an optical disc 12 by a focus optical head 6 as a spot.