Abstract: A sputtering target for fabricating a recording layer of a phase-change type optical recording medium contains a compound or mixture including as constituent elemets Ag, In, Te and Sb with the respective atomic percent (atom. %) of .alpha., .beta., .gamma. and .delta. thereof being in the relationship of 2.ltoreq..alpha..ltoreq.30, 3.ltoreq..beta..ltoreq.30, 10.ltoreq..gamma..ltoreq.50, 15.ltoreq..delta..ltoreq.83 and .alpha.+.beta.+.gamma.+.delta.=100, and a method of producing the above sputtering target is provided. A phase-change type optical recording medium includes a recording layer containing as constituent elements Ag, In, Te and Sb with the respective atomic percent of .alpha., .beta., .gamma. and .delta. thereof being in the relationship of 0<.alpha..ltoreq.30, 0<.beta..ltoreq.30, 10.ltoreq..gamma..ltoreq.50, 10.ltoreq..delta..ltoreq.80, and .alpha.+.beta.+.gamma.+.delta.

Abstract: Information-bearing discs are fabricated from a first disc and a second disc. The first disc has a first substantially planar surface and a second surface opposite to the first surface. The second surface has first information recorded on it by means of local changes in the distance of the second surface from the first surface. The second disc is thicker than the first disc and has opposite, substantially planar, third and fourth surfaces. The fourth surface may have second information recorded on it by means of local changes in the distance of the fourth surface from the third surface. The second disc is secured to the first disc so that the fourth surface faces the second surface.

Abstract: A coating substrate containing an aluminum or aluminum rolled alloy product for thin-film coatings for producing electronic components. The coating substrate prevents the interdiffusion of substrate elements and thin-film coating elements and enables the thin-film coatings to grow completely over irregularities. The local irregularities on the substrate surface to be coated, which have a maximum extension, measured vertically to the substrate surface, of less than 10 um and than 0.1 um, are such that the flanks of the local irregularities can be exposed to material deposition impinging on the substrate surface in a perpendicular manner.

Abstract: An optical disk having high density and excellent quality as well as compatibility with conventional disks is provided. This optical disk is comprised of a disk-shaped substrate formed with a cyclic olefin polymer as its main component and a light-curing resin layer formed on the disk-shaped substrate, wherein a pattern is formed on the light-curing resin layer based on given information. The same effect can be obtained using a heat-curing resin in place of the light-curing resin. Optical disks having superior characteristics can be mass-produced.

Abstract: According to the present invention a data card is provided which comprises a heat-mode laser recording medium on a support and wherein said laser recorder medium is covered by a thin flexible glass layer. The data card has a higher mechanical strength, an improved shelf-life and offers better security with regard to counterfeiting. The heat-mode laser recording medium is preferably a metal layer of which the optical reflectivity or density can be changed by laser exposure. The glass layer is preferably a borosilicate glass having a thickness less than 850 .mu.m.

Abstract: An optical data recording medium utilizing reversible inter-crystalline-amorphous phase changes for recording, reproducing and erasing data as phase changes of a recording film caused by laser beam irradiation. The medium is formed by a lamination of a transparent substrate having tracking guide grooves for laser beam tracking, a base film formed on the substrate, a first protective film formed on the base film, a phase change type recording film formed on the first protective film, a second protective film formed on the recording film, and a reflecting film formed on the second protective film. Thus formed, the medium improves the over-writing characteristics of phase change type optical discs and permits high density recording.

Abstract: An optical information mediumis made up of a transparent substrate, on which are formed a dye recording layer of at least one dyestuff, a reflective layer of metal, and a protective layer in sequence, wherein said protective layer is formed from a plurality layers of resin which are formed sequentially. Further, the reflective layer is made of silver, and the dye recording layer is made of a material which does not contain iodine ion. The protective layer contains a material for trapping molecules and/or ions which corrode the reflective layer. For instance, a metal powder or porous pigment is contained in the protective layer, which is active on or absorbs the molecules and/or ions corroding the reflective layer.

Abstract: In an optical recording information recording medium of a structure having protection layers on both surfaces of a recording layer, overwrite cyclability is improved without deteriorating the reliability of recorded data.To achieve this, the first protection layer is deposited by a sputtering method from a target made of a mixture comprising ZnS and SiO.sub.2 without adding an O.sub.2 gas and a H.sub.2 gas to a sputtering atmosphere, the second protection layer is deposited by a sputtering method using a target made of a mixture comprising ZnS and SiO.sub.2 by adding an O.sub.2 gas and an H.sub.2 gas to the sputtering atmosphere.Especially, an optical information recording medium having a high reliability of recorded data and capable of overwriting of 300,000 cycles or more can be obtained, particularly, by controlling the partial pressure of the added O.sub.2 gas to 10.times.10.sup.-6 -50.times.10.sup.-6 Torr and the partial pressure of the added H.sub.2 gas to 20.times.10.sup.-6 -50.times.10.sup.

Abstract: An phase change optical medium compatible with a flying head can include a substrate, a reflective layer, a first dielectric layer, a phase change information carrying layer, a second dielectric layer and a lubricant layer. The structure and materials used both protect the phase change layer from mechanical damage due to impact and from information-altering heat generated by impact.

Abstract: The invention provides a method of fabricating an optical recording medium comprising a phase change type recording layer containing at least one element selected from In, Ag, Te and Sb. The recording layer is formed by a sputtering technique wherein sputtering is carried out while an inert gas and an oxygen gas are introduced in a vacuum chamber in a sputtering system, so that the number of overwritable cycles can be increased by simple means.

Abstract: This invention provides an optical recording medium complying with the DVD standards, having high sensitivity, possessing high dye film stability, having a high C/N ratio during high density recording, and being capable of reducing jitter components contained in reproduced signals, by finding an organic dye thin film and a medium configuration which can be adapted for a short wavelength semiconductor laser (wavelength 500 to 700 nm) and which are satisfactory in optical characteristics, and chemical, photochemical, physical and thermal stability, the optical recording medium comprising at least a recording layer and a metallic reflecting layer laminated on the surface of a grooved resin substrate transparent to laser light; wherein the recording layer comprises an organic thin film consisting essentially of a styrylcyanine dye of a specific structure and adapted for a short wavelength laser.

Abstract: A digital recording medium, such as a compact disc, having a substrate, a reflective layer and a protective layer includes a near infrared fluorophore in one of the layers. The near infrared fluorophore can be incorporated into the CD by coating, admixing, blending or copolymerization and in an amount to impart a detectable fluorescence from the fluorophore when exposed to electromagnetic radiation having a wavelength ranging from about 670 nanometers (nm) to about 1100 nm. A method of marking a CD with an invisible marking and an apparatus for detecting the fluorophore is further provided.

Abstract: In a phase change-type optical recording medium of absorption coefficient control structure used by land/groove recording system, difference in reproduction characteristics between the land and the groove is minimized while ensuring sufficient output of the tracking signal. In the optical recording medium of the present invention, light absorption coefficient at the wavelength of said recording/reproducing beam is such that: Ac/Aa.gtoreq.0.8 when light absorption coefficient in crystalline region is Ac and light absorption coefficient in amorphous region is Aa; relation between groove width W.sub.G and land width W.sub.L is such that: x=2W.sub.G /(W.sub.L +W.sub.G).gtoreq.1.03; and the relation: .lambda.max.sup.i <.lambda.u.ltoreq..lambda.min.sup.i, and -100x+123.ltoreq.t.sub.R .ltoreq.-100x+126 are satisfied when the wavelength of a local minimum in reflectance spectrum is .lambda.min.sup.i ; the wavelength of the local maximum in the reflectance spectrum nearest to the .lambda.min.sup.

Abstract: A phase-change optical recording medium has a substrate, and a lower heat-resistant protective layer, a recording layer capable of recording and erasing information by utilizing changes in the phase of a phase-change recording material in the recording layer, an upper heat-resistant protective layer and a light reflecting and heat dissipating layer, which are successively overlaid on the substrate in this order, the recording material including Ag, In, Sb and Te as the main elements, at least one additional element selected from the group (1) consisting of B, C, N, Al, Si and P, and at least one additional element selected from the group (2) consisting of halogen atoms and alkali metal elements.

Abstract: A phase change type optical recording medium of Ge--Sb--Te system wherein number of overwritable operation has been increased is provided. The optical recording medium has a substrate and a recording layer of phase change type on the substrate, and the recording layer contains Ge, Sb and Te as its main elements, and at least one of Ag and Au in total content of 0.2 to less than 2.5 at % (excluding 2.5 at %).

Abstract: In an optical disk obtained by pasting two substrates, air bubbles and the like are removed from an adhesive layer between the substrates pasted together, and the thickness irregularity of the adhesive layer is suppressed to an allowable value or less. A spacer having a predetermined thickness is concentrically placed on a substrate. An adhesive is applied onto a surface of the substrate on which the spacer is placed. Another substrate is placed on the surface of the substrate on which the adhesive is applied. The substrates are rotated about the spacer at a high speed. The excessive adhesive sandwiched between the substrates is expelled, together with air bubbles and the like, by using the centrifugal force produced by the rotation. With this process, an adhesive layer having a thickness determined by the thickness of the spacer is left between the two substrates.

Abstract: An information recording carrier has a substrate with at least one fine pattern row. On the substrate, a recording layer, a delamination-proof layer and a protective layer are sequentially superposed. In manufacturing, firstly, the recording layer is formed on the substrate. A first resin is then applied onto the recording layer. The first resin is then cured to form the delamination-proof layer. A second resin is next applied onto the delamination-proof layer. The second resin is then cured to form the protective layer.

Abstract: Monochrome and polychrome color proofs, for the graphic arts industry, having an image carrier containing two layers A and B to control optical dot growth are described. Layer A contains at least one polyolefin and, in a preferred embodiment, a light-reflecting white pigment. Layer B contains at least one binder, at least one light-reflecting white pigment at between 50% and 90% by weight relative to Layer B, and at least one light-absorbing pigment. A process and a means for preparing such monochrome and polychrome color proofs are described.

Abstract: An optical disc comprising a disc having a signal- recording layer, wherein a treated layer having a surface electric resistance of from 1.times.10.sup.3 to 1.times.10.sup.13 .OMEGA. is formed on the signal-recording layer, and the surface of the treated layer is subjected to electrophotographic printing. The optical disc can be desirably used as an optical disc, in which digital signals can be recorded, reproduced or erased, such as a digital audio disc, such as a compact disc, a video disc, or a CD-ROM.

Abstract: The present invention provides a method for internally damping a rotatable storage article which is subject to resonant vibrations. More specifically, the present invention provides a method of improving the damping properties of a rotatable storage article by introducing a viscoelastic material as an inner layer(s) of the rotatable storage article. The invention also provides the damped rotatable storage articles themselves.