An optical pickup device includes two objective lenses having numerical apertures different from each other, a lens holder for holding these objective lenses in common, a cylinder fixed to the lens holder, and four tracking coil pairs affixed onto a cylindrical surface of the cylinder. Two...http://www.google.es/patents/US5687154?utm_source=gb-gplus-sharePatente US5687154 - Optical pickup device which can be adapted to plurality of types of optical disks
Optical pickup device which can be adapted to plurality of types of optical ...
