Patent ID: 6307827
Filing Date: 2001-10-23
Classification: B82Y,G01Q,G11B

Abstract:
An optical device for recording/reproducing data on a signal/data recording surface, comprising a radiation source, a transparent substrate, a waveguide layer provided on the surface of said transparent substrate opposite to said radiation source, and an optical coupling means provided on at least one surface selected from the group consisting of the surface of said waveguide layer and an interface located between said transparent substrate and said waveguide layer, the optical coupling means having a concentric circular periodic structure with an optical axis of said radiation source in the center; wherein said waveguide layer has a cutoff part at the center of said periodic structure; the light from said radiation source excites a guided light that propagates from the periphery to the center of the periodic structure in the waveguide layer by said optical coupling means; and a part of said guided light that reaches said cutoff part leaking out from said optical device to the signal/data recording surface on a flat substrate provided not in contact with but adjacent to said waveguide layer.