Eastman-kodak Company

Randall H Victora

Tukaram K Hatwar

Edward C Gage

Yuan-Sheng Tyan

Giuseppe Farruggia

Charles F Brucker

Timothy J Whitcher

Bane V Vasic

David J Genova

A thin film magnetodielectric (TFM) structure is disclosed which has effective absorption with minimal reflection of electromagnetic radiation over a broad band of frequencies. The thin film magnetodielectric structure has an effective electric susceptibility and effective magnetic susceptibility which are substantially equal for a broad band of electromagnetic wavelengths. The disclosed TFM structure includes layers of thin film magnetic elements which are surrounded by and supported in a dielectric medium. Each thin film element is preferably rectangular in shape and has a thickness substantially less than the long and short axes of the element. Each layer includes a plurality of elements arranged in an orderly array with the long axes of each element in a layer substantially parallel to each other. Either neighboring layers or neighboring stacks of layers have elements whose long axes are oriented at 90&deg;.

Thin film magnetodielectric for absorption of a broad band of electromagnetic waves

An optical recording medium comprising a first substrate with a center mounting hole and having top and bottom surfaces. At least one surface of the substrate is a prerecorded area wherein user data is provided and adapted to be read in an optical recording medium reader device. Over at least a portion of the substrate that can be read by the device is a photosensitive layer comprising a photosensitive material. When the photosensitive material is exposed to a predefined wavelength of light over a predetermined period of time the optical property of at least a portion of the material permanently changes. This change occurs after each copy of the prerecorded area is made. Thereby, the optical recording medium limits the authorized copies of the prerecorded area to a predetermined number.

Copy count protection structure for optical recording medium and method

A compositionally modulated magneto-optic structure includes a plurality of layers defining a layer stack, the overall layer stack including the elements Tb, Fe, and Pb; or the elements Tb, Co, and Pb; or the elements Tb, Fe, and Bi; or the elements Tb, Co and Bi.

Magneto-optic compositionally modulated structure

An optical drive apparatus for use with a multilayer optical data storage device, includes: at least two spaced apart storage layers, each of such layers being adapted to store information; a spacer layer positioned between alternating storage layers; at least one of the storage layers including tracking and/or format information, while another storage layer does not include tracking and/or format information; and writing apparatus including a plurality of radiation beams arranged such that at least one beam is focused on a layer with tracking and/or format information and provides tracking and/or format information to at least one other beam that is focused on a layer to be written that does not have substantial tracking and/or format information.

Optical drive apparatus for use with a multilayer optical data storage

A multilayer optical data storage device is disclosed which has at least two spaced apart storage layers, each of such layers being adapted to store information; a spacer layer positioned between alternating storage layers; and at least one of the layers including tracking and/or format information, and at least one storage layer that does not include substantial tracking and/or format information.

Multilayer optical data storage device

An optical storage device comprising at least two spaced apart recording layers, a spacer layer separating by being positioned between alternating recording layers, and each recording layer including a material responsive to a beam of radiation from a source to record information and at least one recording layer having a different write temperature selected to improve recording performance parameters.

Optical recording medium having at least two separate recording layers

The present invention pertains to a storage medium for use in a magneto-optical storage system. The storage medium comprises two layers of magnetic material, a storage layer and a read layer. The magnetic material of the storage layer has perpendicular (or vertical) axis of orientation; and within the storage layer the direction of magnetic orientation is either parallel or anti-parallel (up or down) relative to the direction of an impinging read radiation beam. In this storage system, the direction of orientation of magnetic material in one direction represents a first logical state, and a direction of orientation in the opposite direction represents a second logical state. The direction of orientation is thus a function of stored data. The read layer has parallel magnetic orientation and a transition temperature above the operating temperature but below the read temperature such that the axis of orientation of the magnetic material and the direction of orientation of the read layer during readout is the same as the corresponding portion of the storage layer.

Magneto-optical storage medium wherein heating a portion of a read layer

A storage medium for use in a magneto-optical information storage medium does not require an initializing magnet. In one embodiment of the medium, a structure includes a memory layer, in which the orientation of magnetic regions perpendicular to the memory layer surface defines the data stored in the memory layer, a reference layer, and an intermediate layer, the intermediate layer mediating an exchange coupling between the memory layer and the reference layer. The combined properties of the storage medium provide a temperature at which, in the presence of a bias magnetic field, data stored in the medium in the form of oriented magnetic domains can be overwritten. In a second embodiment of the invention, a storage medium has two layers, a memory layer and a under layer, of materials with selected magnetic properties. The magnetic properties of the layers are selected to provide magneto-optical storage medium with direct overwriting capability, the operation of the storage medium not requiring an intialization magnet.

Growing community of inventors

Rochester, NY, United States of America

Randall H Victora