Abstract: An information recording medium comprising a substrate (1), a recording layer (2) formed on the substrate in order to record information, a color filter (4) formed on the substrate, and a thermal reflectance variation layer (3) formed on the substrate in order to vary light reflectance by heat incident to irradiation of light and to reflect visible light entering from one side of the substrate through a color filter. High precision color writing or color label writing can be carried out on an information recording medium such as DVD and BD where a label can be written on the surface by irradiating light.

Abstract: An optical-recording medium is provided with at least a first recording layer for recording information optically; and a second recording layer for recording information optically by a light beam that passes through said first recording layer; wherein the track pitch of a recording track that is formed on said second recording layer is narrower than the track pitch of a recording track that is formed on said first recording layer.

Abstract: A recording layer close to a disc surface is divided into at least two recording areas, a main information recording area D1A and an auxiliary information area (BCA) D1C. Grooves are formed in the main information recording area D1A. Marks M are formed in barcode form representing identifying information in the auxiliary information recording area (BCA) D1C. Track grooves G1 or prepits are formed in the recording layer of the auxiliary information recording area (BCA) D1C and have a depth smaller than that of the groove formed in the main information recording area D1A.

Abstract: An information recording medium comprising a substrate (1), a recording layer (2) formed on the substrate in order to record information, a color filter (4) formed on the substrate, and a thermal reflectance variation layer (3) formed on the substrate in order to vary light reflectance by heat incident to irradiation of light and to reflect visible light entering from one side of the substrate through a color filter. High precision color writing or color label writing can be carried out on an information recording medium such as DVD and BD where a label can be written on the surface by irradiating light.

Abstract: An information recording medium (100) includes a recordable area (1) where data information is recordable, an advertisement area (2) where at least either of advertisement information and identification information for identifying the advertisement information, and control area (3) where control information necessary to record the data information in the recordable area or necessary to record the data information at a rate higher than a predetermined recording rate is recorded readably on condition that the advertisement information is reproduced. With this, information recording media such as DVDs where, for example, data information is recordable can be widely used by enhancing the motivation of the users to reproduce advertisement information.

Abstract: There is provided an information recording medium having a plurality of recording layers (layer L0, layer L1) for recording information. At least one of the recording layers (layer L0, layer L1) has a management information area where recording speed management information defining the maximum possible recording speed when recording information is recorded.

Abstract: A groove track and a land track are alternately and spirally formed on an information recording medium. On the land track neighboring the groove track, pre-information indicating position information of a track on a disc is formed as a prepit. On the information recording medium, an embossed area is formed so that information about a copyright and for preventing an illegal copy cannot be rewritten. In the embossed area, an embossed configuration including a pit and a space of predetermined depths is formed. The prepit in the embossed area is formed so that the prepit has an optimized configuration according to a pit length and a space length in the embossed area which the prepit neighbors. Consequently, interference between the embossed configuration and the prepit can be prevented even in a case that the prepit is formed in addition to the embossed configuration in the embossed area.

Abstract: An information recording medium (100) includes: a first recording layer (107); a semitransparent reflective film (108) to reflect at least one portion of laser light for recording with which the first recording layer is irradiated; a second recording layer (207) which is irradiated with the laser light for recording through the first recording layer and the semitransparent reflective film; and a reflective film (208) to reflect the laser light for recording with which the second recording layer is irradiated, thermal conductivity from the second recording layer to the reflective film when the second recording layer is irradiated with the laser light for recording being substantially equal to thermal conductivity from the first recording layer to the semitransparent reflective film when the first recording layer is irradiated with the laser light for recording

Abstract: A rewritable type optical disc includes recording tracks formed with break portions; and recording marks corresponding to predetermined data and formed on the recording tracks. The recording marks are formed over the break portions on the recording tracks. If the predetermined data, such as control data, recorded as the recording mark is illegally altered, the position of the recording marks are changed and some break portions are not covered by the recording marks. Since the return light level of the break portion, which is not covered by the recording mark, is different from the return light level of the break portion covered by the recording mark, such illegal alteration of the predetermined data such as the control data may be detected.

Abstract: A recording layer close to a disc surface is divided into at least two recording areas, a main information recording area D1A and an auxiliary information area (BCA) D1C. Grooves are formed in the main information recording area D1A. Marks M are formed in barcode form representing identifying information in the auxiliary information recording area (BCA) D1C. Track grooves G1 or prepits are formed in the recording layer of the auxiliary information recording area (BCA) D1C and have a depth smaller than that of the groove formed in the main information recording area D1A.

Abstract: An optical-recording medium is provided with at least a first recording layer for recording information optically; and a second recording layer for recording information optically by a light beam that passes through said first recording layer; wherein the track pitch of a recording track that is formed on said second recording layer is narrower than the track pitch of a recording track that is formed on said first recording layer.

Abstract: There is provided an information recording medium having a plurality of recording layers (layer L0, layer L1) for recording information. At least one of the recording layers (layer L0, layer L1) has a management information area where recording speed management information defining the maximum possible recording speed when recording information is recorded.

Abstract: An optical disk with multi-layered structure provided with at least two recording layers is provided. In respective recording layers, tracks are formed, and the track is formed such that the amount of eccentricity is different in respective recording layers. In the method for identifying the recording layer which identifies the recording layer of the optical disk, the recording layer is identified by detecting the amount of the eccentricity set to the track of the respective recording layers.

Abstract: An optical recording medium is provided which can solve a problem of insufficient signal amplitude of one recording layer as compared with the other recording layer in a writable optical recording medium of a conventional double layer structure. An optical recording medium, in which a first substrate having a first groove formed thereon, a first recording layer formed on a first-groove forming surface of the first substrate, a semi-translucent first reflecting layer, an intermediate layer, a second recording layer, a second reflecting layer, and a second substrate having a second groove formed thereon are at least disposed in this order, wherein the optical recording medium further includes a heat conducting layer between the second recording layer and the intermediate layer and a heat insulating layer between the second recording layer and the second reflecting layer.

Abstract: An optical recording medium, in which a first substrate, a first recording layer, a first reflecting layer, an intermediate layer, a second recording layer, a second reflecting layer, and a second substrate are at least laminated, the optical recording medium further including a transcription layer between the second recording layer and the second reflecting layer. The optical recording medium of the invention can solve a problem of insufficient signal amplitude of one recording layer as compared with the other recording layer in a writable optical recording medium of a conventional double layer structure.

Abstract: An optical recording medium of dual layer type is provided which has at least a first substrate, a first recording layer capable of optical recording, a translucent reflecting layer, an intermediate layer, a second recording layer capable of optical recording, and a second substrate in this order from a side where a laser beam for recording, reproduction, or recording/reproduction is applied, wherein the first recording layer is made of an organic dye and the second recording layer is made of a metal material having a higher reflectivity than the organic dye. The optical recording medium provides sufficient signal amplitudes from both recording layers during reproduction, and gives compatibility with a typical optical recording medium during reading.

Abstract: An optical recording medium having a structure comprising at least a first substrate, a first recording layer capable of optical recording, a first reflection layer, an intermediate layer, a second recording layer capable of optical recording, a second reflection layer and a second substrate in this order from a side on which recording, reproducing or recording and reproducing laser light is applied, wherein the intermediate layer is composed of a resin having a glass transition temperature of 90° C. or greater.

Abstract: A groove track and a land track are alternately and spirally formed on an information recording medium. On the land track neighboring the groove track, pre-information indicating position information of a track on a disc is formed as a prepit. On the information recording medium, an embossed area is formed so that information about a copyright and for preventing an illegal copy cannot be rewritten. In the embossed area, an embossed configuration including a pit and a space of predetermined depths is formed. The prepit in the embossed area is formed so that the prepit has an optimized configuration according to a pit length and a space length in the embossed area which the prepit neighbors. Consequently, interference between the embossed configuration and the prepit can be prevented even in a case that the prepit is formed in addition to the embossed configuration in the embossed area.

Abstract: A phase change type information storage medium is provided, which achieves high-speed recording/reproduction. A DVD-RW disc having a substrate formed with grooves, lands, and land pre-pits, on which are laminated a first dielectric layer, a phase-change recording layer, a second dielectric layer, a reflective layer, and an overcoat layer. The disc is rotated at a 3.49-7.0 m/sec linear speed while being irradiated with a laser beam of 600-700 nm wavelength focused by an objective lens of 0.55-0.7 numerical aperture to the phase-change recording layer from the substrate side. The phase-change recording layer is made of a Ge-In-Sb-Te material, and the reflective layer is made of an Ag-Nd-Cu material. The first dielectric layer has a 65-85 nm thickness, the phase-change recording layer has a 10-20 nm thickness, the second dielectric layer has a 13-23 nm thickness, and the reflective layer has a 100-225 nm thickness.

Abstract: An optical recording medium is provided which comprises: a substrate including concentrically or spirally formed grooves each having a V-shaped cross section; a first dielectric layer formed on the substrate; a phase-change recording layer formed on the first dielectric layer; a second dielectric layer formed on the phase-change recording layer; and a metallic reflecting layer formed on the second dielectric layer. In particular, the optical recording medium is so formed that an objective lens having an aperture number of 0.55-0.70 can be used and a laser beam having a wavelength of 600-700 nm and passing through the objective lens is passed through the substrate and then converged on the recording layer, thereby recording or reproducing information on the recording layer in areas corresponding to the grooves.