An optical scanning device (1) for scanning an information layer (4) of an optical record carrier (2), the information layer (4) being covered by a transparent layer (3) of thickness t.sub.d and refractive index n.sub.d. The device comprises a radiation source (11) for generating a radiation beam (12, 15, 20) and an objective system (18) for converging the radiation beam on the information layer. The objective system is characterised in comprising a lens comprising a synthetic resin on a substrate, the total thickness t of the lens satisfying the condition: Formula (I), where FWD+t.sub.d/n.sub.d<0.51, and FWD is the free working distance between the lens (18) and carrier (2) and .PHI. is the entrance pupil diameter of the lens (18), where t, t.sub.d, .PHI. and FWD are expressed in millimeters.