Abstract: The object of the present invention is to provide a technology which has high compatibility and can provide users with conveniences. A new system recording medium 100 has a center hole 112 formed on a recording disk 110 and a center hole 121 formed on a center hub 120, so that the recording medium 100 can respond to both an old system driving unit having a centering member coupling with the center hole 112 and a new system driving unit 300 having a second centering member 313 coupling with the center hole 121. Moreover, the old system recording medium is a recording medium providing a recording disk having a center hole incorporated in a cartridge having a center hub, and has a structure where the center hole is coupled both with a first centering member 312 of the new system driving unit 300 and with the centering member of the old system driving unit.

Abstract: The azo-metal chelate dye of the present invention is formed, for example, from zinc (divalent) as a center metal ion and an azo compound bonded with a coupler component having an amino group and a fluorine-substituted alkylsulfonylamino group subjected to condensed ring-formation to have a 1,3,4-thiazole ring as a diazo component.

Abstract: To obtain an optical information recording medium in a favorable initially crystallized state, by carrying out initial crystallization at a high linear velocity (specifically at least about 25 m/s), i.e. at a linear velocity higher than the erasable linear velocity for the optical information recording medium.

Abstract: A phase-change recording material used for an information recording medium utilizing a crystalline state as a non-recorded state and an amorphous state as a recorded state, which has the composition of the following formula (1) as the main component: (Sb1?xSnx)1?y?w?zGeyTewM1z??formula (1) wherein each of x, y, z and w represents atomicity, x, z and w are numbers which satisfy 0.01?x?0.5, 0?z?0.3 and 0?w?0.1, respectively, and the element M1 is at least one element selected from the group consisting of In, Ga, Pt, Pd, Ag, rare earth elements, Se, N, O, C, Zn, Si, Al, Bi, Ta, W, Nb and V, and (I) when z=0 and w=0, y is a number which satisfies 0.1?y?0.3, (II) when 0<z?0.3 and w=0, y is a number which satisfies 0.05?y?0.3, and (III) when 0?z?0.3 and 0<w?0.1, y is a number which satisfies 0.01?y?0.3.

Abstract: An optical recording medium which comprises a print-receiving layer as the outermost layer on the side opposite to the light incidence side, wherein a pattern is formed on the print-receiving layer.

Abstract: To provide an optical recording medium capable of high density recording or readout of optical information by a laser beam having a short wavelength. An optical recording medium comprising a substrate and a recording layer formed on the substrate, capable of recording or readout of information by irradiation with light, wherein the recording layer contains a 7-aminocarbostyril compound of the following formula (I): in the formula (I), X is an oxygen atom or a sulfur atom, R1 is a hydrogen atom or a linear or branched alkyl group which may be substituted, R6is a linear or branched alkyl group which may be substituted, and n=1 to 4.

Abstract: By use of a substrate which can be stably formed and has a relatively small groove depth, a very high density optical recording medium having good recording/reading characteristics is provided. In an optical recording medium of a surface incidence type, in which a reflective layer, a recording layer containing a dye as a main component and a cover layer are sequentially formed on a substrate having guide grooves formed therein, a guide groove part on a far side from a plane of incidence of a recording/reading light beam on the cover layer is set as a recording groove part, and reflected light intensity in a recorded pit portion formed in the recording groove part is increased by a phase shift and is set higher than reflected light intensity in unrecorded.

Abstract: A dual-layer optical recording medium, which is formed by adhering a disk substrate (inverted-stack structure) formed by stacking a reflective layer (1) and a recording layer (1) on a substrate (1) and a disk substrate (conventional-stack structure) formed by sequentially stacking a recording layer (2) and a reflective layer (2) on a transparent substrate (2) with a transparent resin layer interposed therebetween, is prepared such that the transparent resin layer has a product obtained by multiplying the thickness by the elastic modulus at 25±5° C. falling within the range of not less than 2.0×104 MPa·?m to not more than 30.0×104 MPa·?m, resulting in suppressing excessive deformation involving an adjacent track portion produced by recording optical information in the recording layer (1) of the inverted-stack structure, thereby reducing crosstalk and providing satisfactory recording and/or reading characteristics in high-speed recording applications.

Abstract: In an optical recording medium having two recording layers of a first recording layer and a second recording layer, the second recording layer contains metallized azo dyes represented by the following general formula (I) or (II), and recording characteristics of the second recording layer are improved by having optical density of 1.3 times as large as, or 1.3 times greater than, that of a dye contained in the first recording layer. (In this regard, rings A1 and A2 are nitrogen-containing heteroaromatic rings, rings B1 and B2 are aromatic rings, and X is alkyl group substituted by at least two fluorine atoms.

Abstract: An optical recording method for recording mark length-modulated information on a recording medium by using a plurality of recording mark lengths. The optical recording method comprises the steps of: when a time length of one recording mark is denoted nT (T is a reference clock period equal to or less than 25 ns, and n is a natural number equal to or more than 2), (i) dividing the time length of the recording mark nT into ?1T, ?1T, ?1T, ?2T, ?2T, . . . , ?iT, ?iT, . . .

Abstract: A phase-change recording material on which high speed recording/erasing is possible, which has excellent recording characteristics, which has a high storage stability of recording signals and which is excellent in the repeated recording durability, and an information recording medium using the above material are provided. A phase-change recording material characterized by containing as the main component a composition represented by {(Sb1?xGex)1?yIny}1?z?wMzTew wherein x, y, z and w are numbers satisfying 0.001?x?0.3, 0?y?0.4, 0?z?0.2 and 0?w?0.1, and M is at least one element selected from lanthanoids, provided that z and w are not 0 at the same time.

Abstract: An optical recording medium which comprises a print-receiving layer as the outermost layer on the side opposite to the light incidence side, wherein a pattern is formed on the print-receiving layer.

Abstract: Provided is an optical recording method for recoding information on a phase-change optical recording medium at a low linear velocity by use of a divided pulse method. When forming a plurality of recording marks by use of a constant divided pulse number m, a light irradiation time period of recording light for recording a recording mark having a time length of nT is divided in the order of {?1T, ?1T, ?2T, ?2T, . . . , ?iT, ?iT, . . . , ?mT, ?mT} (in which m is a natural number representing a divided pulse number, ?i (1?i?m) is a real number greater than 0, ?i (1?i?m?1) is a real number greater than 0, and ?m is a real number equal to or above 0).

Abstract: To provide a process for producing a laminated optical recording medium with improved production efficiency, with which in production of an optical recording medium by a 2P process, a resin forming an interlayer and a light transmitting stamper can easily be separated without applying any constrained load. A process for producing a laminated optical recording medium, which comprises applying a precursor of an ultraviolet-curing resin on a recording layer containing an organic dye formed on a polycarbonate substrate, disposing a polypropylene light transmitting stamper comprising a nonpolar member having a concavo-convex shape thereon, curing the ultraviolet-curing resin and then easily separating the light transmitting stamper without applying any constrained load so that the concavo-convex shape is transcribed on the resin layer.

Abstract: The object of the present invention is to provide a technology which has high compatibility and can provide users with conveniences. A new system recording medium 100 has a center hole 112 formed on a recording disk 110 and a center hole 121 formed on a center hub 120, so that the recording medium 100 can respond to both an old system driving unit having a centering member coupling with the center hole 112 and a new system driving unit 300 having a second centering member 313 coupling with the center hole 121. Moreover, the old system recording medium is a recording medium providing a recording disk having a center hole incorporated in a cartridge having a center hub, and has a structure where the center hole is coupled both with a first centering member 312 of the new system driving unit 300 and with the centering member of the old system driving unit.

Abstract: The main object of the present invention is to provide a recording medium which makes high densification of information possible, particularly a write-once-read-many optical recording medium having good recording signal characteristics to a wide range of recording powers. The present invention is one to accomplish the above object by providing a recording medium having a recording layer, whereby recording is carried out by heating the recording layer, characterized in that the recording layer contains a substance A which decomposes at a temperature which the recording layer reaches when heated for recording, and a substance B which does not undergo a chemical reaction or phase change at a temperature which the recording layer reaches when heated for recording.

Abstract: An optical recording medium simultaneously having higher recording characteristics and storage stability than ever, is obtained. An optical recording medium comprising at least a phase change recording layer, a first diffusion preventing layer, a second diffusion preventing layer and a protective layer formed in this order on a substrate, characterized in that the first diffusion preventing layer and the second diffusion preventing layer comprise a non-gas element and nitrogen and/or oxygen as the main components, the non-gas element in each of the first diffusion preventing layer and the second diffusion preventing layer, is the same, and the content (atomic %) of nitrogen and/or oxygen contained in the second diffusion preventing layer, is larger than the content (atomic %) of nitrogen and/or oxygen contained in the first diffusion preventing layer.

Abstract: The azo-metal chelate dye to which the present invention is applied is a compound formed as follows: for example, 1,3,4-thiadiazole ring is selected as the diazo component; the diazo component is combined with a coupler component having condensed rings including a fluorine-substituted alkylsulfonylamino group and an amino group, to form an azo dye compound; and the azo dye compound forms chelate bonds with at least one metal selected from the group consisting of Co, Ni, Cu and Pd. Here, two absorption bands (OD1 and OD2) are seen in the absorption spectrum, which is measured in a range of 400 to 800 nm wavelengths. The azo-metal chelate dye is characterized in that the optical density ratio (OD2/OD1) of the two absorption bands is greater than 1.25. By using this azo-metal chelate dye, an optical recording medium capable of high-speed recording is provided.

Abstract: An information recording method allows optical information having a recording mark length smaller than a spot diameter of laser light to be recorded on an optical recording medium having a recording layer, at high density by laser light pulse application. The information recording method has: a power calibration step of determining a recording power for recording a signal having a predetermined signal length in the recording layer using the laser light; and a complementing step of complementing, based on the recording power determined in the power calibration step, a recording power for recording a signal having a signal length equal to or less than ½ of the spot diameter of the laser light in the recording layer using the laser light. In the information recording method, for example, an extremely small mark, such as a 2T signal, can be precisely formed.