Abstract: Disclosed is a molded disc useful in optical information recording carriers, the disc is comprised of a copolymer of methyl methacrylate and ethyl acrylate, wherein the copolymer is comprised of 97 to 99.9 wt. % of methyl methacrylate and 0.1 to 3 weight % ethyl acrylate, has a molecular weight in the range of from 90,000 to 115,000, has a Tg of from 105° C. to 115.

Abstract: A recording medium is fabricated by forming a light reflecting layer on a dye recording layer capable of recording information, with a sputtering mechanism. The sputtering mechanism has a target, an electromagnet in the shape of a solenoid disposed in horizontally facing relationship to the target, and a coaxial cylindrical permanent magnet disposed in vertically facing relationship to the target. The permanent magnet has an outer circumferential region serving as an N pole and an inner circumferential region serving as an S pole. The electromagnet is electrically connected to a DC power supply via a controller which controls the intensity of a current flowing through the electromagnet.

Abstract: An information recording medium includes at least a recording layer formed on a substrate, the recording layer including a phase change layer in which a reversible phase change is caused between a crystalline state and an amorphous state by irradiation of a light beam, and a crystallization-ability improving layer for improving a crystallization ability of the phase change layer. The crystallization-ability improving layer is formed before the phase change layer is formed. Thus, crystal nucleus generation and crystal growth are caused during formation of the phase change layer, so that at least a portion of the phase change layer is in the crystalline phase after the formation. Thus, information signals can be recorded/reproduced at a high density and a high linear velocity, and thus the present invention provides a highly reliable optical information recording medium.

Abstract: The present invention provides organic dye compounds which exert excellent recording characteristics in high-density optical recording media, and uses thereof. The present invention solves the objects of the present invention by providing non-symmetric trimethine cyanine dyes having a specific structure and properties, light absorbents and optical recording media comprising the cyanine dyes, and a process for preparing the cyanine dye comprising a step of reacting either 3,3-dimethyl-5-nitroindolium compounds or 3,3-dimethyl-5-sulfonamideindolium compounds, which have a reactive methyl group or an appropriate leaving group, with 3,3-dimethylbezoindolium compounds, which have a reactive methyl group or an appropriate leaving group.

Abstract: The present invention discloses a rewritable phase-change optical disk having a recording material of a five-element alloy, Te—(Ge,Bi,Sb)—X, wherein X is B (boron) or C (carbon); Te (tellurium) ranges from 47 to 60 atomic percentage (at. %); Ge (germanium) ranges from 12 to 48 at. %; and Si (silicon) together with Sb (antimony) range from 5 to 41 at. %, based on the total atomic number of Te, Ge, Bi and Sb; and B or C range from 0.05 to 4 at. %, based on the total atomic number of Te, Ge, Bi, Sb and X.

Abstract: A multi-rewritable optical recording medium includes a surface plasmon super-resolution layer. The surface plasmon super-resolution layer is a three-layer structure including a first dielectric layer, a second dielectric layer, and a metal layer sandwiched between said first dielectric layer and said second dielectric layer. The metal layer with a certain thickness performs the surface plasmon effect when a laser beam with a suitable wavelength irradiates thereon. By the design and arrangement of the surface plasmon super-resolution layer, the small size of information-carrying pits and the recording marks in the range of around 100 nm is accessible. As a result, the super-resolution without the limit of the optical diffraction is achieved.

Abstract: An optical information medium comprises a supporting substrate, an information recording surface 4 on the supporting substrate and a light-transmitting layer of resin on the information recording surface. Recording light and/or reproducing light are incident on the information recording surface through the light-transmitting layer. The light-transmitting layer is obtained by curing a resin layer containing an ultraviolet-curing cationic resin. If the light-transmitting layer is formed by repeating the cycle of resin coating and curing or drying a plurality of times, the uniformity of thickness of the light-transmitting layer can be much more improved and the amount of warpage can be much more reduced. Repetition of the cycle of resin coating and curing or drying is also effective for resins other than the ultraviolet-curing cationic resin.

Abstract: The object of this invention is to provide a rewritable phase change type optical recording medium and an optical recording apparatus that are good in erasure characteristics and small in jitter even in high linear velocity high density recording, are unlikely to cause cross erasure even in the use of a substrate with a narrow track width, are unlikely to be deteriorated in signal quality even after repeated irradiation with a laser beam, and are good also in storage durability.

Abstract: Ultraviolet rays are irradiated in a space through which a cationic ultraviolet curable composition falling from a nozzle passes before reaching a disc substrate. The cationic ultraviolet curable composition which has been irradiated with ultraviolet rays, is distributed in a ring form on the surface of the disc substrate. Another disc substrate is then superposed in this distributed surface to spread the composition by pressing or by the weight of the other disc substrate itself.

Abstract: A phase change optical recording medium has on a substrate a recording layer consisting essentially of a Sb base thin film and a reactive thin film. The Sb base thin film is formed by depositing a Sb base material containing at least 95 at % of Sb to a thickness of 70-150 Å. The reactive thin film is formed of a material which forms a phase change recording material when mixed with Sb. The reactive thin film is typically formed of an In—Ag—Te or Ge—Te material. Stable write/read characteristics are accomplished at the first overwriting, initializing operation is eliminated, and rewriting is impossible at the same linear velocity as recording.

Abstract: An optical recording medium of the invention comprises a phase change type recording layer on a surface of a substrate with reading light incident on the recording layer through the substrate, and a dielectric layer provided in contact with the recording layer and on a side of the recording layer on which the reading light is incident. The substrate has a groove acting as a guide groove and a land between adjacent grooves so that the groove and land are used as recording tracks. The phase change type recording layer contains Ag, In, Sb and Te as main components, and has a thickness tR defined by tR≦&lgr;p/20 where &lgr;p is a wavelength of the reading light. The dielectric layer has a thickness td1 that is represented in terms of an optical path length at the wavelength &lgr;p and defined by &lgr;p/2≦td1.

Abstract: In phase change optical recording media wherein initialization process of the recording layer has been the rate determining and cost-increasing factor in the production of the medium, the production cost is reduced by reducing the time required for the initialization and simplification of the initialization process. Stable writing/reading properties are also realized from immediately after the initialization.

Abstract: An optical recording medium comprises a substrate, a recording film formed on the substrate, and a protective film formed by applying and curing a protective film forming composition on the recording film, wherein the protective film forming composition comprises 60 to 85 wt % of trimethylolpropane triacrylate modified with ethylene oxide, and 25 to 65 parts by weight of tripropyleneglycol diacrylate per 100 parts by weight of the trimethylolpropane triacrylate modified with ethylene oxide.

Abstract: A phase change optical disc having a substrate and a first dielectric layer formed on the substrate. A recording layer is formed on the first dielectric layer and is convertible into one of an amorphous state and a crystal state according to the power of an incident beam. A second dielectric layer is formed on the recording layer. A reflective layer is formed on the second dielectric layer. The first dielectric layer is formed of a material having a refractive index of 2.7 or more with respect to the incident beam.

Abstract: The invention relates to terpolymers particularly suited for use in high density optical data storage media. The terpolymers are suitable for use in DVD recordable and rewritable media. The invention further relates to methods for making DVD recordable and rewritable media from these terpolymers.

Abstract: An optical information recording medium includes a first dielectric protective layer, a recording layer provided on the first dielectric protective layer, including a material represented by a chemical formula of Ag&agr;In&bgr;Sb&ggr;Te&dgr;, wherein &agr;, &bgr;, &ggr; and &dgr; respectively represent an atomic percent of Ag, an atomic percent of In, an atomic percent of Sb, and an atomic percent of Te, and satisfy the conditions of: 1≦&agr;<10, 1<&bgr;≦20, 35≦&ggr;≦70, 20≦&dgr;≦35, &agr;+&bgr;+&ggr;+&dgr;=100, 4&bgr;−&dgr;≦0, &ggr;−2&dgr;≧0, and &ggr;−8&agr;≧0, a second dielectric protective layer provided on the recording layer, and a light reflection and heat dissipation layer provided on the second dielectric protective layer.

Abstract: An optical recording medium structure and its method of manufacture. The optical recording medium structure includes, from bottom to top, a transparent substrate, a first dielectric layer, a first buffer layer, a recording layer, a second buffer layer, a second dielectric layer, an optical compensation layer and a reflection layer. The optical recording medium structure is manufactured by forming the first dielectric layer, the first buffer layer, the recording layer, the second buffer layer, the second dielectric layer, the optical compensation layer and the reflection layer in sequence over the transparent substrate. The first buffer layer and the second buffer layer serves to prevent the diffusion of at least one element from the recording layer into the first and the second dielectric layer and vice versa. The optical compensation layer enhances thermal sensitivity of the recording layer during an optical read/write operation.

Abstract: The invention provides an optical recording medium preventing deterioration of an organic dye, having improved durability and being highly reliable, as well as a process for producing the same. The recording layer (3) including an organic dye as the main component, and the reflective layer (4) comprising a metal selected from Cu, Ag and Au or an alloy containing at least one of these metals, are formed in this order on substrate (2). An ultraviolet-curable material is laminated on the reflective layer (4) and cured by irradiation with UV rays at 200 to 1000 mJ/cm2 in such a manner that a cure shrinkage factor is not more than 10% by volume to form the protective layer (5) so that the organic acid content in the resulting ultraviolet-cured resin is not more than 10 ppm by weight, whereby the optical disk (1) is obtained. The dye is preferably a cyanine type dye, and the reflective layer is preferably Cu, Ag or an alloy containing at least one of these metals.

Abstract: An information recording medium having recording, reproducing, and rewriting characteristics better than those of prior art media. The media has a recording layer made of a material represented by the following formula: Gex−wSbyTezMw, wherein 0.13≦x≦0.22, 0.20≦y≦0.32, 0.53≦z≦0.60, 0≦w≦0.06, x+y+z=1, and M is any one of Na, Mg, Al, P, S, Cl, L, Ca, Sc, Zn, Ga, As, Se, Br, Rb, Sr, Y, Zr, Nb, Ru, Rh, Cd, In, Sn, I, Cs, Ba, La, Hf, Ta, Re, Os, Ir, Hg, Tl, Pb, Th, U, Ag, Cr, W, Mo, Pt, Co, Ni, Pd, Si, Au, Cu, V, Mn, Fe, Ti and Bi.

Abstract: A high-density optical disk includes reflective layers respectively formed at both information-recorded surfaces of a first substrate, and semitransparent layers respectively formed at one information-recorded surface of each of second and third substrates. The second and third substrates are respectively bonded at both sides of the first substrate.