Abstract: An information recording medium excellent in long storage and capable of high-density recording, method of manufacturing the information recording medium, and information recording material are provided. Pulse laser light is focused onto a recording layer in which a thermosetting epoxy resin having a skeleton with high planarity and a curing agent are polymerized to form a recording mark. With a molecular weight between cross-linking points of a cured material of the recording layer being set to be equal to or smaller than 2000 and, more preferably, equal to or smaller than 500, a distance between recording marks (cavities) can be shortened.

Abstract: Disclosed is an information recording medium which, when inserted into a recording/reproducing device, can be run in an updated state intended by a disc supplier since a recordable layer can be specified as a layer to be run first. For example, in an optical disc including an L1 layer which is a read-only recording layer and an L0 layer which is a recordable layer, layer specifying information for specifying the L0 layer in priority to the L1 layer is recorded as an information recording layer to be run first when the optical disc is inserted into the optical disc device which carriers out recording or reproduction of information with respect to the optical disc.

Abstract: 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, 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.

Abstract: An optical recording medium includes: N recording layers (where N?4); a number of kinds of layer intervals between the recording layers adjacent to each other being an integer M equal to or less than a minimum integer equal to or more than log2(N); and one or more AB blocks including four recording layers with a first layer interval A, a second layer interval B, and the first layer interval A formed in order in the one or more AB blocks. When the M as the number of kinds of layer intervals is M?3, the optical recording medium has a part of a third layer interval C as a layer interval between a recording layer forming an AB block and a recording layer adjacent to the recording layer, the adjacent recording layer being included in other than the AB block including the recording layer.

Abstract: An information recording medium is composed of a substrate having a microscopic pattern constituted by a continuous substrate of grooves formed with a groove portion and a land portion alternately, a recording layer, and a light transmitting layer. The microscopic pattern is formed with satisfying a relation of P??/NA, wherein P is a pitch of the land portion or the groove portion, ? is a wavelength of reproducing light, and NA is a numerical aperture of an objective lens. The land portion is formed with wobbling so as to be parallel with each other for both sidewalls of the land portion. Auxiliary information and a reference clock is recorded alternately. Information is recorded in the recording layer corresponding to a land portion by either one change of reflectivity difference and refractive index difference in the recording layer.

Abstract: An optical recording medium includes a recording and reading layer that is previously staked or formed afterward and has no concavo-convex pattern for tracking control, and a servo layer in which a concavo-convex pattern or a groove for tracking control is formed. Information can be recorded in the recording and reading layer while tracking is performed using the servo layer.

Abstract: The optical storage medium comprises a substrate layer and a data layer disposed on the substrate layer, the data layer having a mark/space data structure being arranged in tracks, wherein on a first track, the marks are enlarged in length and the spaces are shortened in length, and on an adjacent track, the marks are shortened in length and the spaces are enlarged in length. The track pitch between adjacent tracks is particularly below a diffraction limit of ?/2*NA of a pickup for reading of the data.

Abstract: Simple design of a multilayer optical recording medium is achieved while suppressing interlayer crosstalk and confocal crosstalk in the multilayer optical recording medium. Simple recording and reading control by a recording and reading unit is also achieved. The multilayer optical recording medium includes at least three or more recording and reading layers deposited one above the other with intermediate layers interposed therebetween, and information can be read by light irradiation from the layers. The intermediate layers have film thicknesses of two types or less, and all the recording and reading layers except the recording and reading layer farthest from a light incident surface have substantially the same optical constant.

Abstract: Provided is an optical disc in which at least a light reflecting layer and a light transmitting layer that includes a cured film of an ultraviolet curable composition are stacked on a substrate, and information is reproduced by making a blue laser beam be incident on the optical disc from a side of the light transmitting layer, wherein an elastic modulus (25° C.) measured by indenting a Vickers indenter having a vertex angle of 136° under a load of 100 mN into a surface of the cured film of the ultraviolet curable composition is 1,500 MPa or less; and a loss modulus (E?) at 60° C. in a dynamic viscoelastic spectrum of the cured film measured at a frequency of 3.5 Hz is 10 MPa or less. Thus, warpage is reduced during curing and plastic deformation is less likely even under a load for a long period of time.

Abstract: A series of optical recording media is provided to reduce a burden on an optical pickup by introducing a standardized idea among a plurality of optical recording media. In the series of optical recording media, optical recording media are of a plurality of types, each optical recording medium including a plurality of planar recording and reading layers with no projections and depressions for tracking control, and a servo layer with projections and depressions for tracking control. The plurality of optical recording media have different numbers of stacked recording and reading layers. The plurality of optical recording media have different numbers of stacked recording and reading layers. The positions of the servo layers from the corresponding light incident surfaces are standardized among the plurality of optical recording media. The position of at least one recording and reading layer from the corresponding light incident surface is standardized among the plurality of optical recording media.

Abstract: A series of optical recording media is provided to reduce a burden on an optical pickup by introducing a standardized idea among a plurality of optical recording media. In the series of optical recording media, optical recording media are of a plurality of types, each optical recording medium including a plurality of planar recording and reading layers with no projections and depressions for tracking control, and a servo layer with projections and depressions for tracking control. The plurality of optical recording media have different numbers of stacked recording and reading layers, and the positions of the servo layers with respect to the corresponding light incident surfaces are standardized among the plurality of optical recording media.

Abstract: An optical record carrier (30) comprising a plurality of information layers formed above a first surface of a substrate wherein at least one of the information layers is a re-writable cache layer is disclosed. The data that is read more than once is copied on to the re-writable cache layer when the recording/reproducing device is not in active use. Next time when the same data is requested, it can be read from the re-writable cache layer. This is advantageous since the data is stored un-fragmented on the re-writable cache layer and the re-writable cache layer can have higher read speeds than the other information layers in the optical record carrier. Therefore, the re-writable cache layer can improve the system performance in terms of read speed.

Abstract: A recording medium includes first information selected from a plurality of information patterns and second information selected from another plurality of information patterns for the true-false judgement. A true-false judging device performs a statistic analysis when any coincidence is found between the readout combination of the first and second information and registered combination patterns, to identify an inspected recording medium as a forged product based on the result of the statistic analysis.

Abstract: The present invention provides an optical recording medium including a substrate and a recording layer on the substrate having a squarylium metal chelate compound with a central metal. The recording layer includes a mixture of squarylium metal chelate compounds having ligands of the same type as well as metals of two or more types as the central metal. It is preferable that the recording layer includes a squarylium metal chelate compound having a bivalent metal as its central metal and a squarylium metal chelate compound having a metal other than a bivalent metal as its central metal.