MULTIIPLE LAYER OPTICAL RECORD CARRIER SCANNING

摘要

An optical scanning device for scanning a record carrier, the carrier having a first information layer and a second information layer. The device includes a radiation source for generating a radiation beam of a predetermined wavelength, and an objective lens. The objective lens has a first surface divided into at least a first set of zones and a second set of zones. The first set of zones is arranged to focus incident radiation of the predetermined wavelength to scan the first information layer. The second set of zones is arranged to focus incident radiation of the predetermined wavelength to scan the second information layer.