Abstract: A multilayer optical recording medium includes: a substrate; a plurality of optical recording layers provided on the substrate; and a plurality of intermediate layers each provided between adjoining optical recording layers disposed in a thickness direction. In this multilayer optical recording medium, each of the intermediate layers has a birefringence property and a principal axis direction of birefringence of each intermediate layer is oriented at 90 degrees with respect to that of an adjoining intermediate layer.

Abstract: A simultaneous two-photon absorption recording-reproduction method of recording and reproducing a data by inducing changes in the fluorescence intensities in a recorded part and an unrecorded part by simultaneous two-photon absorption, comprising: generating a fluorescence quencher in a two-photon recording part; and inducing quenching by excitation energy transfer between the fluorescence quencher and a fluorescent dye to physically quench the fluorescence by reproduction light from the fluorescent dye and decrease the fluorescence intensity in the recorded part; and a simultaneous two-photon absorption recording material for use in the method capable of generating a fluorescence quencher capable of inducing quenching by excitation energy transfer between the fluorescence quencher and a fluorescent dye by simultaneous two-photon absorption and physically quenching the fluorescence from the fluorescent dye.

Abstract: A multilayer optical recording medium includes: a substrate; a plurality of optical recording layers provided on the substrate; and a plurality of intermediate layers each provided between adjoining optical recording layers disposed in a thickness direction. In this multilayer optical recording medium, each of the intermediate layers has a birefringence property and a principal axis direction of birefringence of each intermediate layer is oriented at 90 degrees with respect to that of an adjoining intermediate layer.

Abstract: An optical information recording medium including a substrate having successively disposed thereon a recording layer, an interlayer, a pressure sensitive adhesive layer and a cover film in which information is recordable and reproducible by irradiating laser light and the pressure sensitive adhesive layer contains a polymer having a glass transition temperature Tg of 0° C. or lower, as well as a method for producing an optical information recording medium including adhering a cover layer to a surface of a recording layer so that a pressure sensitive adhesive layer is abutted on the surface of the recording layer, and an optical information recording medium produced by the method.

Abstract: The present invention is an optical information recording medium comprising a substrate having disposed in an order thereon a recording layer, an interlayer, and a cover layer, wherein recording and reproduction are carried out by the irradiation with a laser light having a wavelength in the range of 380 to 500 nm through a lens having a lens numerical aperture NA of 0.7 or more, wherein the recording layer is a layer of an organic substance and the thickness of the interlayer is within a range of 1 nm to 9 nm.

Abstract: The present invention provides an optical information recording medium including a substrate with an on-groove and an in-groove, having successively disposed thereon a dye recording layer and a transparent sheet, wherein a width of the on-groove ranges from 50 to 140 nm, and a barrier layer is formed between the recording layer and the transparent sheet. The invention also provides an optical information recording method including irradiating the optical information recording medium with laser light from the side of the medium provided with a cover layer to form a void at a signal pit portion in the dye recording layer and thereby carrying out recording of information as well as an optical information recording medium on which information has been recorded by the method.

Abstract: The present invention provides an optical information recording medium that includes a substrate including a groove with a track pitch of 200 to 400 nm and a groove depth of 20 to 150 nm and having successively disposed thereon a light reflecting layer, a recording layer containing a dye in which information is recorded by irradiation with a laser beam having a wavelength of no greater than 450 nm, an adhesive layer, and a cover layer with a thickness of 0.01 to 0.5 mm. A surface of the optical information recording medium on a side disposed with the cover layer has a center surface average roughness (SRa1) of no greater than 3.0 nm when measured over a large surface area and a center surface average roughness (SRa2) of no greater than 3.0 nm when measured over a minute surface area.

Abstract: An optical information recording medium including a substrate, a recording layer formed on the substrate, and a transparent sheet provided on the recording layer via an adhesive layer. The adhesive layer has a peak of loss modulus at a temperature of 0° C. or lower, and exhibits an E1?/E2? ratio of 2.0 or less, wherein E1? and E2? represent storage moduli of the adhesive layer at 25° C. and 80° C., respectively.

Abstract: The invention provides an optical information recording medium, for use with a laser irradiating a laser beam having a wavelength of 380 to 500 nm through an objective lens with a numerical aperture of at least 0.7, the optical information recording medium comprising, in the following order: a substrate; a recording layer; a layer of acrylic adhesive; and a cover layer. A light reflecting layer may be provided between the substrate and the recording layer. Also a cover layer formed by an acrylic adhesive material may be provided instead of the layer of the acrylic adhesive material and the cover layer.

Abstract: The invention provides a method for manufacturing an optical information recording medium having a track pitch of 200 to 400 nm and a groove depth of 20 to 150 nm, and being capable of recording and reproducing using a light with a wavelength of 450 nm or less, the method at least comprising: a metal reflective layer forming step for forming a metal reflective layer on a substrate; a recording layer forming step for forming a recording layer of an organic dye type on said metal reflective layer; and a cover layer forming step for forming a cover layer on said recording layer; in this order.

Abstract: The present invention provides a magnetic particle-coated material having a layer including a CuAu type or Cu3Au type ferromagnetic ordered alloy phase on an organic support. Further, the present invention provides a method of manufacturing a magnetic particle-coated material that sequentially includes a step of manufacturing alloy particles capable of forming a ferromagnetic ordered alloy phase, a step of coating an organic support with the alloy particles to form a coating film, and a step of annealing the coating film in a reducing atmosphere to make the alloy particles into magnetic particles, and further includes a step of oxidizing the alloy particles, the oxidizing step being performed between the alloy particle manufacturing step and the annealing step.

Abstract: The invention provides a method for manufacturing an optical information recording medium having a track pitch of 200 to 400 nm and a groove depth of 20 to 150 nm, and being capable of recording and reproducing using a light with a wavelength of 450 nm or less, the method at least including: a metal reflective layer forming step for forming a metal reflective layer on a substrate; a recording layer forming step for forming a recording layer of an organic dye type on said metal reflective layer; and a cover layer forming step for forming a cover layer on said recording layer; in this order.

Abstract: An optical recording medium includes a substrate having successively disposed thereon a light-reflecting layer, a recording layer and a cover layer, with recording and playback being effected by irradiating the medium with a laser beam having a wavelength of 450 nm or less from the side disposed with the cover layer, wherein a sputter layer having a thickness of 1 to 80 nm is formed between the recording layer and the cover layer, and the sputter layer and the cover layer are adhered with an adhesive. The sputter layer preferably has a thickness within a range from 2 to 50 nm and is preferably formed from a simple substance of Si, Zn, Ag, Al, Ti, Sn or Ge, a compound comprising at least one of the simple substances, or a combination thereof.

Abstract: The present invention provides an optical information recording medium including a substrate having a groove that has a track pitch of 200 to 400 nm and a depth of 20 to 150 nm, the substrate having successively disposed thereon a light-reflective layer, a recording layer on which information is recordable by a laser beam having a wavelength of 450 nm or less, an adhesive layer containing an adhesive, and a cover layer having a thickness of 0.01 to 0.5 mm, wherein a surface of the light-reflective layer at a side thereof at which the recording layer is disposed has a ten-point average roughness Rz of 70 nm or less, a central surface average roughness SRa of 30 nm or less, and an average projection diameter Dv, at a height of 15 nm from a reference plane, of 75 nm or less.

Abstract: An optical information recording medium including a substrate, a recording layer, and a cover layer in this order; wherein information is recorded or reproduced by irradiating a laser beam having an wavelength in the range of 380 to 500 nm on the recording layer through a lens having a numerical aperture NA of 0.7 or more; the recording layer includes an organic substance; and the extinction coefficient k of the recording layer is at least 0.1 and less than 0.3.

Abstract: An information recording medium showing a high light-resistance has a recording layer containing a dye compound having the following formula (I-1) or (I-2): in which each of A1, A2, B1 and B2 is a substituent; each of Y1 and Z1 is a group of atoms required for forming a carbon ring or a heterocyclic ring; each of E and G is a group of atoms required for forming a conjugated double bond chain; X1 is ?O, ?NR or ?C(CN)2, wherein R is a substituent; X2 is —O, —NR or —C(CN)2, wherein R is a substituent; each of L1, L2, L3, L4 and L5 is a methine group which may have a substituent; Mk+ is an onium ion containing a positively charged onium atom to which no hydrogen atom is attached; each of m and n is 0, 1 or 2; each of x and y is 0 or 1; and x is an integer of 1 to 10.

Abstract: An optical information recording medium achieving stable recording and reading characteristics and having good storage stability including light resistance and heat resistance by preventing colorants contained in a recording layer therein from being decomposed, and also an optical information recording medium that can be individually differentiated from others by outward appearance. The optical information recording medium includes a substrate having successively disposed thereon at least a light-reflective layer, a recording layer on which information is recorded by laser light of a wavelength no longer than 500 nm, and a cover layer containing a UV absorbent that blocks out light of a wavelength no longer than 400 nm and/or a dye that blocks out light of a wavelength no shorter than 500 nm. A second substrate may be disposed opposite to a side of the optical information recording medium that is irradiated with light and may be colored.

Abstract: An optical information recording medium including a substrate having a groove that has a track pitch of 200 to 400 nm and a depth of 10 to 150 nm, the substrate having successively disposed thereon a light-reflective layer, a recording layer and a cover layer, wherein information is recordable and reproducible by irradiating a laser beam having a wavelength of 500 nm or less from a side of the medium disposed with the cover layer, and the light-reflective layer contains aluminum or an aluminum alloy.

Abstract: A high-density optical information recording medium comprising, on a substrate, a recording layer capable of recording information by irradiation of a laser beam at a wavelength of from 380 to 500 nm, wherein the recording layer contains a compound represented by the following general formula (I): where R1 to R6 each represents, independently, a substituent, M represents a metal atom, and n represents an integer of 1 or greater.

Abstract: An optical information recording medium including a substrate, a recording layer formed on the substrate, and a transparent sheet provided on the recording layer via an adhesive layer. The adhesive layer has a peak of loss modulus at a temperature of 0° C. or lower, and exhibits an E1′/E2′ ratio of 2.0 or less, wherein E1′ and E2′ represent storage moduli of the adhesive layer at 25° C. and 80° C., respectively.