International Business Machines Corporation

Victor B Jipson

Kie Y Ahn

Thomas H DiStefano

Daniel Rugar

Gary C Bjorklund

Hans J Coufal

Wen Yaung Lee

Martin Y Chen

Roger W Barton

Harold N Lynt, Jr

An optical storage medium for storing binary data adapted to be written upon by a laser forming an array of encoded spots is composed of a substrate possibly covered with a mirror layer and including a matrix of a transparent dielectric material such as a polymer upon which a vacuum deposited discontinuous film of nucleated metallic islands is deposited having thicknesses of less than about 100 .ANG.. The particles extend up to 1000 .ANG. transversely generally parallel to the surface of said substrate. The islands are separated by a short distance for facilitating coalescence of particles together to effect writing of spots at low energy by the lateral motion and gathering of the islands during heating of the islands by a laser beam or the like. Each spot represents a data bit in a binary position code. The matrix material has low thermal conductivity and preferably a low melting point to facilitate writing at low energy.

Optical storage media with discontinuous thin metallic films

A process for accessing disk tracks in an optical storage disk using a laser beam passed through an acousto-optic deflector which generates an undeflected beam and at least one deflected beam both of which are focussed on the surface of the disk. The deflected beam is used to read or write data and the undeflected beam is used to follow a servoing structure on the disk.

High speed track access for optical disks using acousto-optic deflector

Reversible phase change storage material is thermally isolated in a storage medium by means of grooves in the substrate and at least one layer of a thermally conductive dielectric material.

Thermal design for reversible phase change optical storage media

An optical storage medium incorporates stacked servo and data layers with the pattern of the servo layer being prepared prior to preparation of the data layer. The servo pattern comprises an undulation in a very thin film of high optical index material on the surface of the substrate of the medium. The undulating layer containing the servo pattern is separated from the active layer of the medium by a thin dielectric spacer film. The data layer is employed for formation of vesicular, or ablative or other marks forming surface discontinuities formed by any of the usual pit forming techniques. The preformatted servo information formed in the servo layer as buried undulations in the thin film is read out in amplitude or phase contrast. The thin undulating layer is of a significantly different index of refraction from the substrate and the next intervening layer. This layer can be transparent or semi-transparent. A smoothing layer is then applied over the phase-contrast layer to reduce any undulations at the top surface on which the active layer is formed. The amount of energy absorbed by the active layer of the structure is optimized for the data recording wavelength by choice of thickness of the smoothing layer.

High performance optical storage medium with separate mechanical servo

A method of and structure for optical recording by energy-induced homogenization or fractionation is disclosed. When the method involves fractionation, a film is provided that contains a homogeneous mixture of a matrix material and an incident energy absorbing material. A spot on the film is treated with sufficient energy in the form of electric fields, radiation or heat, or combinations thereof to effect fractionation and/or homogenization of the film which will undergo further physical state transition only under treatment with additional energy. In a preferred embodiment, the fractionation is effected by laser radiation. The laser irradiated spot becomes inhomogeneous and can be detected by the resulting changes in its optical properties. When the method involves homogenization, a film is provided that contains a inhomogeneous mixture. The energy treated spot in this case becomes homogeneous without undergoing a phase transition between the amorphous and crystalline phases. Numerous combinations of fractionation and homogenization can result in the writing and erasing of information in a storage device.

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San Jose, CA, United States of America

Victor B Jipson