Centre National De La Recherche Scientifique

Nippon Telegraph and Telephone Corporation

Nippon Telephone and Telegraph Corporation

Akinori Furuya

Hiroshi Yoshikawa

Manabu Yamamoto

Abel C Rousset

Philippe Tailhades

Takaya Tanabe

Laurence Bouet

Toshifumi Ohkubo

Corine Despax

Tadayuki Imai

Masahiro Endo

Shogo Yagi

Yoshiaki Kurokawa

An optical memory medium () has cores () each constituting a planar optical waveguide and clads () sandwiching each core, and has a data image () in which data is recorded as a scattering factor and a pair of positioning marks () which are scattering factors required for positioning at an interface between a core () and a clad () or in the core (). A read light () travels while spreading in the core () and scatters and interferes by the data image (), and data is reproduced from a data reproduction light () generated by this scattering and interference. A pair of positioning lights () are caused to enter the core () with offsets with respect to the read light () in opposite directions along a thickness direction of the core (), and scatter and interfere at the pair of positioning marks (). Incidence positions of the lights emitted from a light source () with respect to the core () in a thickness direction of the core () are controlled based on intensities of a pair of positioning mark lights () generated by this scattering and interference.

Optical memory reproduction apparatus and incidence positioning method for read light thereof

A magneto-optical recording medium has a recording layer and a reflective layer on a substrate. The recording layer has a layered structure in which at least one spinel ferrite (or rutile-type oxide or hematite) layer and at least one garnet ferrite layer are piled together. It is preferable that the layered structure is formed on tracks where data are recorded. A manufacturing method comprises the steps of heat treatment in the range of 500-700&#xb0; C., preferably 600-630&#xb0; C., after the formation of the recording layer. In the magneto-optical recording and playback device to record and play back data, the wavelength of light for recording data is different from that for reading data, which is preferable for a magneto-optical recording medium comprising a garnet ferrite layer.

Magneto-optical recording medium, manufacturing method thereof and magneto-optical data recording and playback device

This invention relates to magneto-optical recording media such as magneto-optical disks and cards, manufacturing methods of the medium and a magneto-optical recording and playback device to record and play back data using the magneto-optical recording media. The magneto-optical recording medium of the present invention has a recording layer and a reflective layer on a substrate, and the recording layer has a layered structure in which at least one spinel ferrite (or rutile-type oxide or hematite) layer and at least one garnet ferrite layer are piled together. It is preferable that the layered structure is formed on tracks where data are recorded. The manufacturing method of the present invention comprises the steps of heat treatment in the range of 500-700&deg; C., preferably 600-630&deg; C., after the formation of the recording layer. In the magneto-optical recording and playback device to record and play back data of the present invention, the wavelength of light for recording data is different from that for reading data, which is preferable for a magneto-optical recording medium comprising a garnet ferrite layer.

Opto-magnetic recording medium with a garnet ferrite recording layer, and opto-magnetic information recording/reproducing device

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Kodaira, Japan

Akinori Furuya