Optical information recording and/or reproducing apparatus, optical information recording and/or reproducing method, optical information recording medium, and solid immersion lens

Abstract

An optical information recording and/or reproducing apparatus comprises: a focusing unit () which collects generated near-field light on an optical disc (); a first detector () which receives light reflected by the optical disc () and outputs an electric signal according to the quantity of the received light; and a distance control circuit () which controls the distance between the focusing unit () and a light entrance surface of the optical disc (), using the electric signal that is output from the first detector (), and the optical disc () has at least N (N is an integer of 2 or greater) number of information layers, and a distance dfrom the light entrance surface to a first information layer which is most distant from the light entrance surface and a distance dn from the light entrance surface to an Nth information layer which is closest to the light entrance surface satisfy the relationship of dn≧d×(1/25). As a result, servo control can be accurately performed regardless which information layer, out of a plurality of information layers of an optical disc, information is recorded to or reproduced from.