Patent ID: 6995886

Claim:
An optical scanning device for scanning a first information layer ( 23 ) of a first optical record carrier ( 21 ) with a first radiation beam ( 27 ) and a second information layer ( 47 ) of a second optical record carrier ( 45 ) with a second radiation beam ( 49 ), the device including: a radiation source ( 26 ) for supplying said first and second radiation beams, and a lens system ( 24 ) having one optical axis ( 33 ) and operating: as a catadioptric system for said first radiation beam in order to transform this beam to a first focused radiation beam ( 35 ) having a first numerical aperture (NA 1 ) so as to form a first scanning spot ( 36 ) in the position of said first information layer, and as a refractive system for said second radiation beam in order to transform this beam to a second focused radiation beam ( 56 ) having a second numerical aperture (NA 2 ), different from said first numerical aperture, so as to form a second scanning spot ( 53 ) in the position of said second information layer.