Abstract: A method and apparatus for improving optical disk recording performance is disclosed, which comprises reading data from an optical disk while writing data to the disk in order to verify the data, to control the power of the recording laser and to prevent overwriting of the disk.

Abstract: A method of reducing the surface noise of optical disk products of the type having a surface relief pattern is disclosed. In one embodiment, an adherent layer is applied to the substrate of the disk before it is coated with the recording material layer. In another embodiment, a polymeric replica produced from a master disk is treated by spin coating or dipping in a weak solvent which serves to smooth out microscopic roughness thereby removing surface irregularities. In a third embodiment, a metal coated replica is subjected to an electropolishing operation which again serves to remove a small amount of metal material, preferentially from "high spots".

Abstract: An improved optical data storage medium is reponsive to incident electromagnetic radiation, and the surface or a surface region of the medium includes a layer of heat sensitive material which has a textured surface pattern in the form of a regular array of grooves or protuberances, the dimensions of the surface features which constitute said textured surface pattern being in the sub-micron range. The textured surface pattern is overcoated with a thin film of an alloy, said alloy comprising (1) a first component which is at least one of ruthenium, rhodium, palladium, osmium, iridium and platinum; and (2) at least one other metallic element, preferably from Groups Va, VIa, VIIa, and Ib of the Periodic Table of elements according to Mendeleev.The preferred alloy compositions for such data storage media contain platinum and tungsten.

Abstract: A data storage medium is provided which is suitable for production or replication by moulding, casting, embossing or a similar process against a tool. The data storage medium comprises an optically sensitive layer at or adjacent to one surface of the medium, said one surface of the medium comprising a plurality of topographical features or structures disposed in a regularly repeating pattern, said pattern being free from undercutting so that the medium can be produced and/or replicated by molding, casting, embossing or similar process against a tool. The optically sensitive layer is preferably overcoated with a thin film of a metallic material which conforms to the topography of said surface.

Abstract: An optical data storage medium is disclosed for use in an optical read/write system using an optical read wavelength of W, the medium including a textured region having raised areas and depressed areas disposed in a regular array with a period (pitch) not greater than W and a depth (peak-to-trough) in the range 10 to 1,000 nanometers. The medium comprises a substrate and a regular array of zones of magneto-optic material disposed at least over the peaks and troughs of the surface texture and conforming to the surface texture. In many embodiments, there is also a layer or a regular array of zones of an optically reflective material. In one embodiment, the texture is shallow, being generally in the range 10 to 120 nanometers. In a second embodiment, the depth of the texture is at least one tenth of the value of W. In any of the embodiments, there may be a dielectric layer over the top of the structure.

Abstract: A pre-formatted optical data storage member is described in which format zones are generated by the provision in the surface of the optical medium of a "moth-eye" structure, i.e. regular surface pattern in the form of an arrangement of grooves or protuberances. The pitch and depth of the pattern is such that when irradiated with illumination of predetermined optical characteristics, the format zones display a reflectivity substantially lower than that of the remainder of the optical storage member. Methods of producing optical data storage members with such pre-formatting are also described.

Abstract: A data storage medium is provided which is suitable for production or replication by moulding, casting, embossing or a similar process against a tool. The data storage medium has a surface or a surface region which is strongly absorbent of at least a predetermined band of wavelengths of electromagnetic radiation. The surface or surface region includes a layer of a material which undergoes a large volume change or degradation and has a regular, sinuous textured surface pattern which is free from undercutting. The textured surface pattern is coated with a thin film of platinum or a platinum alloy, the thickness of the overcoating preferably being such as to give no more than 10% transmission of incident radiation.A method of storing information on such a data storage medium is also disclosed. The data storage medium may be prepared in blank form for use as the consumer desires, or it may be pre-recorded in part or in entirety.