US 6,307,827 B1 · Optical device and information recording and reproducing device

Abstract

An optical device and an information recording and reproducing device, which comprise a radiation source, a transparent substrate, a waveguide layer provided on the surface of the transparent substrate opposite to the radiation source and an optical coupling means that is provided on the surface of the waveguide layer or on the interface between the transparent substrate and the waveguide layer and that has a concentric circular periodic structure with an optical axis of the radiation source in the center; wherein the waveguide layer has a cutoff part at the center of the periodic structure; the light from the radiation source excites a guided light that propagates from the periphery to the center of the periodic structure in the waveguide layer by the optical coupling means; and a part of the guided light leaks out, at the cutoff part, to a signal surface on a flat substrate provided adjacent to the waveguide layer. With such a structure, an optical device and an optical information recording and reproducing device can greatly improve the coefficiency of light utilization and largely enhance the signal reproducing sensitivity.

Claims72

Dependent claims

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.

An optical device for recording/reproducing data on a signal/data recording surface, comprising a radiation source, a light collecting means that converts light radiated from said radiation source to a parallel light, a transparent cone part having an optical axis of said parallel light as a central axis, a transparent buffer layer formed on the lower surface of said cone part, a waveguide layer formed on said buffer layer;

wherein said waveguide layer has a cutoff part at the central axis of said cone part;
the refractive index of said cone part is larger than the refractive index of said waveguide layer, which is larger than the refractive index of said buffer layer;
said parallel light is refracted at the surface of said cone part, passes through said buffer layer and enters said waveguide layer to excite a guided light that propagates from the periphery to the center in said waveguide layer;
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.

1 more element

An optical information recording and reproducing 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 a surface selected from the group consisting of the surface of said waveguide layer and the 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.

An optical information recording and reproducing device for recording/reproducing data on a signal/data recording surface, comprising a radiation source, a light collecting means that converts light radiated from said radiation source to a parallel light, a transparent cone part having an optical axis of said parallel light as a central axis, a transparent buffer layer formed on the lower surface of said cone part, a waveguide layer formed on said buffer layer;

wherein said waveguide layer has a cutoff part at the central axis of said cone part;
the refractive index of said cone part is larger than the refractive index of said waveguide layer, which is larger than the refractive index of said buffer layer;
said parallel light is refracted at the surface of said cone part, passes through said buffer layer and enters said waveguide layer to excite the guided light that propagates from the periphery to the center in said waveguide layer;
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.

1 more element

Dependencies are inferred from the claim text.

Optical device and information recording and reproducing device

Life of this patent

Optical device and information recording and reproducing device

Life of this patent

Abstract

Claims72