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 recording medium includes a first disk, a second disk, and an adhesive layer for bonding the first disk to the second disk. The first disk and the second disk each include a substrate having a first surface and a second surface and having a gradient on an outer peripheral portion of the second surface, two or more information signal layers disposed on the first surface, an intermediate layer disposed between adjacent information signal layers, and a cover layer covering the two or more information signal layers and the intermediate layer. The second surface of the substrate included in the first disk faces the second surface of the substrate included in the second disk with the adhesive interposed therebetween.

An optical recording medium includes a first disk, a second disk, and an adhesive layer for bonding the first disk to the second disk. The first disk and the second disk each include a substrate having a first surface and a second surface and having a gradient on an outer peripheral portion of the second surface, two or more information signal layers disposed on the first surface, an intermediate layer disposed between adjacent information signal layers, and a cover layer covering the two or more information signal layers and the intermediate layer. The second surface of the substrate included in the first disk faces the second surface of the substrate included in the second disk with the adhesive interposed therebetween.

The present invention relates to a read-only optical information recording medium in which at least one reflection film and at least one light transmission layer are laid in order on a substrate and from which information is reproduced by blue laser. The reflection film includes a metal oxide containing Sn and Zn or a metal oxide containing In. The reflection film has a film thickness of 20 nm or more and 70 nm or less.

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.

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.

A configuration for reducing a possibility of data recording or reproduction being unperformable due to a reading error of disc management information is realized. A data processing unit records management information corresponding to a first surface as main management information on the first surface which is a data recording surface on which data recording is performed and further records mirror management information having the same content as the main management information on a second surface different from the first surface. The management information is, for example, a temporary disc management structure (TDMS) including defect region information of one surface of a disc. When one piece of management information between the main management information and the mirror management information is successfully read, data recording or reproduction can be correctly performed.

Provided is an optical recording medium including two or more recording layers, and a light irradiation surface that is irradiated with light for recording an information signal on the two or more recording layers. Among the two or more recording layers, at least one layer other than a layer located on the deepest side from the light irradiation surface includes an oxide of a metal A, an oxide of a metal B, and an oxide of a metal C. The metal A is at least one kind among W, Mo, and Zr, the metal B is Mn, and the metal C is at least one kind among Cu, Ag, and Ni. Ratios of the metal A, the metal B, and the metal C satisfy a relationship of 0.46x1 (provided that, x1=a/(b+0.8c), a representing an atomic ratio [atom %] of the metal A with respect to the sum of the metal A, the metal B, and the metal C, b representing an atomic ratio [atom %] of the metal B with respect to the sum of the metal A, the metal B, and the metal C, and c representing an atomic ratio [atom %] of the metal C with respect to the sum of the metal A, the metal B, and the metal C.

Provided is an optical recording medium including two or more recording layers, and a light irradiation surface that is irradiated with light for recording an information signal on the two or more recording layers. Among the two or more recording layers, at least one layer other than a layer located on the deepest side from the light irradiation surface includes an oxide of a metal A, an oxide of a metal B, and an oxide of a metal C. The metal A is at least one kind among W, Mo, and Zr, the metal B is Mn, and the metal C is at least one kind among Cu, Ag, and Ni. Ratios of the metal A, the metal B, and the metal C satisfy a relationship of 0.46x1 (provided that, x1=a/(b+0.8c), a representing an atomic ratio [atom %] of the metal A with respect to the sum of the metal A, the metal B, and the metal C, b representing an atomic ratio [atom %] of the metal B with respect to the sum of the metal A, the metal B, and the metal C, and c representing an atomic ratio [atom %] of the metal C with respect to the sum of the metal A, the metal B, and the metal C.