Abstract: The invention relates to thermo-optic writing on an information support comprising a substrate on which there is deposited an organic sub-layer covered by a metal layer.The invention provides a writing process which consists in creating in the metal layer a plastic deformation due to the thrust exerted by the localized swelling of the sub-layer. The writing produces a relief impression without piercing of said metal layer.

Abstract: The invention relates to thermo-optical inscription or writing on a data support comprising an organic intermediate layer (2) covered by a metal layer (3).The invention relates to a writing process consisting of creating in the metal layer 3 a plastic deformation as a result of the gaseous pressure exerted due to the local thermal degradation of intermediate layer 2. Inscription produces a bulge-like impression without perforating the metal layer (3).The invention more particularly applies to the thermo-optical inscription and storage of data on an optically readable support by phase or amplitude contrast.

Abstract: A protected optical disc adapted for optical recording and playback of information (particularly digital recording) with a rigid element carrying the recording surface, and a flexible element permeable to optical radiation, one of these two elements having the shape of a dish. At least one of the elements is provided with a central hole for receiving a driving shaft, with the joined annular portion or portions of the two elements concentric with the central hole.

Abstract: The invention relates to protected optical disk structures. The invention relates placing the sensitive layer on a substrate, which is only joined to the other elements constituting the box by a single fixing area, located in the central part of said box, in order that deformations of the box do not affect the smoothness and flatness of the substrate.

Abstract: A protected optical disc intended for the recording of information is protected against the harmful consequences of humidity by the presence of a hydrophylous material situated at a particular distance from the recording surface, which thus retains a high sensitivity during the write or read operations. The invention may be applied especially to discs intended for digital recording.

Abstract: Thermo-optic writing on an information support in which an organic sublayer covered by a metal layer is deposited on a substrate. A plastic deformation due to the thrust exerted by the localized swelling of the sub-layer is created in the metal layer to produce a relief impression without piercing of the metal layer.

Abstract: A thermo-optic data writing process and record in which focussed radiation is directed onto a data medium made up of a substrate, an organic layer directly deposited thereon with the interface therebetween being non-reflective and, on the organic layer, a metal layer of an alloy of metals selected to provide desired adhesion, range of deformation and shock resistance to rupture, for example, incorporating gold, silver or copper. Gas evolution by local degradation of the organic layer produces a bubble in the metal.

Abstract: Thermo-optical writing of information used for such applications as archival storage is performed on a medium in which a ductile metal film layer is stretched beyond the elastic limit under the pressure exerted by a contiguous layer of thermally deforming organic substance and is partially permeable to radiation produced by a light beam. An optical cavity formed between the ductile layer and a reflecting metal film layer is tuned so that the reflection factor of the information medium at the light-radiation wavelength increases with the deformation induced by the light beam.

Abstract: The invention relates to a reversible memory structure with thermo-optical inscription or writing and optical reading on a moving support.According to the invention, the memory structure deposited on a substrate (1) is constituted by a double layer (2 and 3). A second alloy layer (3) at ambient temperature in the martensitic phase is deposited on a first thermally deformable layer (2). A heat pulse creates a deformation in the first layer, which deforms the martensitic alloy layer. A more powerful heat pulse raises the alloy layer to a temperature above its transformation point from the martensitic phase to another crystallographic phase and erases the inscribed deformation.Particular application to optical disks.

Abstract: The invention relates to a permanent memory structure supported by a moving substrate.This substrate is formed by two metal layers (9, 10) vacuum-deposited on the relatively inexpansible substrate (1). One of the two metal layers is very expansible (9), while the other layer (10) is relatively inexpansible, but ductile. During inscription by the laser beam, the beam energy absorbed by the layers (9, 10) produces an elongation of the expansible layer (9), which deforms the ductile layer (10) by stretching it beyond the elastic limit. There is a permanent deformation of the two-layer assembly, without perforation.Particular application to optical disks.