A polarizing beam splitter for separating an upstream beam from a downstream beam according to the polarization of an incident beam is provided between first and second light sources emitting laser beams at respective wavelength and an objective lens. A phase plate for providing a phase difference to...http://www.google.fr/patents/US7088645?utm_source=gb-gplus-shareBrevet US7088645 - Optical pickup apparatus compatible with different types of optical recording mediums
Optical pickup apparatus compatible with different types of optical ...
