In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, in read and write operations by a compatible optical disc device conforming to a plurality of optical disc standards, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.

An information recording medium according to the present disclosure is an information recording medium of a write-once-read-many type and records or reproduces information when irradiated with laser light. The information recording medium includes: a substrate; a plurality of information layers at least one information layer of which includes a recording film that is a W—O-based recording film comprising at least tungsten (W) and oxygen (O); and a dielectric film A in contact with the W—O-based recording film, the dielectric film A comprising at least 30 mol % tin oxide.

An optical disc recording medium includes: a substrate; at least one recording layer formed on at least one side of the substrate; and a cover layer formed on the substrate and the recording layer. The cover layer having a first thickness with reference to a surface of the substrate, in an inside of a circle having a first radius from a center of the substrate. The cover layer having a second thickness larger than the first thickness with reference to the surface of the substrate, on a circumference having a second radius longer than the first radius from the center of the substrate. The cover layer having a third thickness smaller than the first thickness with reference to the surface of the substrate, on a circumference having a third radius longer than the first radius and shorter than the second radius from the center of the substrate.

An optical disc recording medium includes: a substrate; at least one recording layer formed on at least one side of the substrate; and a cover layer formed on the substrate and the recording layer. The cover layer having a first thickness with reference to a surface of the substrate, in an inside of a circle having a first radius from a center of the substrate. The cover layer having a second thickness larger than the first thickness with reference to the surface of the substrate, on a circumference having a second radius longer than the first radius from the center of the substrate. The cover layer having a third thickness smaller than the first thickness with reference to the surface of the substrate, on a circumference having a third radius longer than the first radius and shorter than the second radius from the center of the substrate.

An optical information storage medium includes a substrate and a multilayer polymeric film. The multilayer polymeric film has a first surface and an opposite second surface that extend the length of the multilayer polymeric film. The second surface is adhered to a surface of the substrate. The multilayer polymeric film includes a plurality of coextruded alternating polymeric active data storage layers and polymeric buffer layers.

An optical information storage medium includes a substrate and a multilayer polymeric film. The multilayer polymeric film has a first surface and an opposite second surface that extend the length of the multilayer polymeric film. The second surface is adhered to a surface of the substrate. The multilayer polymeric film includes a plurality of coextruded alternating polymeric active data storage layers and polymeric buffer layers.

3D optical data storage refers to forms of optical data storage in which information can be recorded and/or read with 3D resolution. 3D optical media are generally limited in areal density by the diffraction limit of laser light used to read and/or write data to and/or from the optical media. It is thus advantageous to find ways to store data on 3D optical media with a spot size below the diffraction limit of an associated laser reader to further increase areal density of the optical media. A hybrid approach that utilizes plasmon technology to access a surface layer of the 3D optical media with an extremely small spot size and photon technology to access interior layers of the 3D optical media with a larger spot size may substantially increase overall data density of the 3D optical media.

A recording medium according to one embodiment of the present disclosure includes a recording layer and an optical thin film. The recording layer includes a heat-sensitive color-developing composition and a photothermal conversion material. The photothermal conversion material absorbs a wavelength in an infrared region and generates heat. The optical thin film is provided on one surface of the recording layer. The optical thin film reflects the wavelength in the infrared region and transmits a wavelength in a visible region.

A recording medium according to one embodiment of the present disclosure includes a recording layer and an optical thin film. The recording layer includes a heat-sensitive color-developing composition and a photothermal conversion material. The photothermal conversion material absorbs a wavelength in an infrared region and generates heat. The optical thin film is provided on one surface of the recording layer. The optical thin film reflects the wavelength in the infrared region and transmits a wavelength in a visible region.

An optical storage medium, a method for preparing an optical storage medium, and a system are provided. In this application, the optical storage medium includes a substrate and at least one data layer, the data layer includes a recording layer and a spacer layer, the recording layer is located on the spacer layer, and the data layer is located above the substrate. The recording layer may store data, the recording layer includes an area in which a phase change material is distributed and an area in which no phase change material is distributed, and the two different areas may indicate different data.