Abstract: An information recording medium is prepared by forming a multi-layered film, including an information recording layer, on a substrate by transferring the substrate heated at an average heating rate of at least 10° C./second in a heating zone, along consecutive film-forming zones, and consecutively forming layers forming the multi-layered film in the film-forming zones.

Abstract: A lens formed of a fluorophosphate glass, which has an optical-function surface and has a positioning reference surface for positioning and fixing the lens in the fixing tool (and also for determining the direction in the direction of the optical axis), so that the above optical-function surface is not damaged, both the optical-function surface and the positioning reference surface being transfer surfaces formed by the transfer of form of a molding surface of a mold according to precision press-molding.

Abstract: A glass for use in chemical reinforcement for use in a substrate of an information recording medium, having a composition comprising, denoted as mol %: SiO2 47 to 70%? Al2O3 1 to 10% (where the total of SiO2 and Al2O3 is 57 to 80%) CaO 2 to 25% BaO 1 to 15% Na2O 1 to 10% K2O 0 to 15% (where the total of Na2O and K2O is 3 to 16%) ZrO2 1 to 12% MgO 0 to 10% SrO 0 to 15% (where the ratio of the content of CaO to the total of MgO, CaO, SrO, and BaO is greater than or equal to 0.5) ZnO 0 to 10% (where the total of MgO, CaO, SrO, BaO, and ZnO is 3 to 30%) TiO2 0 to 10% and the total content of the above-stated components is greater than or equal to 95%. A glass for use in chemical reinforcement for use in the substrate of an information recording medium employed in a perpendicular magnetic recording system, in which the glass exhibits the glass transition temperature is greater than or equal to 600° C.

Abstract: A glass for use in chemical reinforcement for use in a substrate of an information recording medium, having a composition comprising, denoted as mol %: SiO2 47 to 70%? Al2O3 1 to 10% (where the total of SiO2 and Al2O3 is 57 to 80%) CaO 2 to 25% BaO 1 to 15% Na2O 1 to 10% K2O 0 to 15% (where the total of Na2O and K2O is 3 to 16%) ZrO2 1 to 12% MgO 0 to 10% SrO 0 to 15% (where the ratio of the content of CaO to the total of MgO, CaO, SrO, and BaO is greater than or equal to 0.5) ZnO 0 to 10% (where the total of MgO, CaO, SrO, BaO, and ZnO is 3 to 30%) TiO2 0 to 10% and the total content of the above-stated components is greater than or equal to 95%.

Abstract: To provide a high-refractivity high-dispersion optical glass having excellent stability An optical glass which is formed of an oxide glass containing 30 to 70 cationic % of Bi3+ and has a liquidus temperature of 800° C. or lower.

Abstract: Provided are optical glasses having a phosphate-containing composition that can materialize highly useful optical properties including high-refractivity and high-dispersion properties; an optical glass comprising P2O5, SiO2 and Li2O as essential components, comprising Na2O and K2O as optional components, having an Li2O/(Li2O+Na2O+K2O) molar ratio of from ? to 1 and having an Abbe's number (?d) of 30 or less, and an optical glass comprising P2O5, SiO2 and Li2O as essential components, having the property of transmittance that when light is caused to vertically enter one of two plane and mutually parallel optically polished surfaces of a sample of the glass having a thickness of 10.0±0.1 mm and caused to exit from the other surface, the wavelength at which the transmittance represented by the ratio of transmitted light intensity to incidence light intensity (transmitted light intensity/incidence light intensity) comes to be 70% is 510 nm or less, having a refractive index (nd) of 1.

Abstract: An optical glass comprising, by mol %, 0.1 to 40% of SiO2, 10 to 50% of B2O3, 0 to 10% of total of Li2O, Na2O and K2O, 0 to 10% of total of MgO, CaO, SrO and BaO, 0.5 to 22% of ZnO, 5 to 50% of La2O3, 0.1 to 25% of Gd2O3, 0.1 to 20% of Y2O3, 0 to 20% of Yb2O3, 0 to 25% of ZrO2, 0 to 25% of TiO2, 0 to 20% of Nb2O5, 0 to 10% of Ta2O5, over 0.1% but not more than 20% of WO3, 0 to less than 3% of GeO2, 0 to 10% of Bi2O3, and 0 to 10% of Al2O3, the mass ratio of the content of SiO2 to the content of B2O3, SiO2/B2O3, being 1 or less, the optical glass having a refractive index nd of 1.86 to 1.95 and an Abbe's number ?d of (2.36?nd)/0.014 or more but less than 38.

Abstract: An optical glass comprising, by mass %, 12 to 40% of SiO2, 15% or more but less than 42% of Nb2O5, 2% or more but less than 18% of TiO2, (provided that Nb2O5/TiO2 is over 0.6), 0.1 to 20% of Li2O, 0.1 to 15% of Na2O, and 0.1 to 25% of K2O, and having an Abbe's number ?d of 20 to 30, a ?Pg,F of 0.016 or less and a liquidus temperature of 1,200° C. or lower.

Abstract: A glass material for mold pressing, comprised of a core portion comprised of a multicomponent optical glass containing at least one readily reducible component selected from among W, Ti, Bi, and Nb, and a covering portion covering the surface of said core portion, comprised of a multicomponent glass containing none or a lower quantity of said readily reducible component than is contained in said core portion. A glass material for mold pressing comprising a core portion comprised of a fluorine-containing multicomponent optical glass and a covering portion covering the surface of said core portion, comprised of a multicomponent glass containing none or a lower quantity of fluorine than is contained in said core portion. A method for manufacturing an optical glass element comprising heat softening a glass material that has been preformed into a prescribed shape, and conducting press molding with a pressing mold, employing the above glass material of the invention.

Abstract: An optical glass having high refractivity and a low sag temperature and having a low-temperature softening property that enables precision press-molding is provided, and the optical glass contains, by mol %, 5 to 50% of B2O3, 3 to 50% of SiO2, 5 to 40% of TiO2, 1 to 40% of ZnO, 5 to 20% of La2O3, 0 to 10% of Gd2O3, 0 to 15% of Nb2O5, 0 to 10% of ZrO2, 0 to 5% of Ta2O5, 0 to 10% of Bi2O3, 0 to 10% of MgO, 0 to 8% of CaO, 0 to 10% of SrO, 0 to 10% of BaO, provided that the total content of MgO, CaO, SrO and BaO is 15% or less, 0 to 20% of Li2O, and 0 to 5% of Na2O, optionally containing Sb2O3 as a refining agent, and having a refractive index (nd) of 1.8 or more and an Abbe's number (?d) of 35 or less.

Abstract: According to one aspect of the present invention, provided is glass for use in substrate for information recording medium, which comprises, denoted as molar percentages, a total of 70 to 85 percent of SiO2 and Al2O3, where SiO2 content is equal to or greater than 50 percent and Al2O3 content is equal to or greater than 3 percent; a total of equal to or greater than 10 percent of Li2O, Na2O and K2O; a total of 1 to 6 percent of CaO and MgO, where CaO content is greater than MgO content; a total of greater than 0 percent but equal to or lower than 4 percent of ZrO2, HfO2, Nb2O5, Ta2O5, La2O3, Y2O3 and TiO2; with the molar ratio of the total content of Li2O, Na2O and K2O to the total content of SiO2, Al2O3, ZrO2, HfO2, Nb2O5, Ta2O5, La2O3, Y2O3 and TiO2 ((Li2O+Na2O+K2O)/(SiO2+Al2O3+ZrO2+HfO2+Nb2O5+Ta2O5+La2O3+Y2O3+TiO2)) being equal to or less than 0.28.

Abstract: The present invention relates to an optical glass having a refractive index (nd) of greater than or equal to 1.65 and an Abbé number (? (nu)d) of greater than or equal to 50 for use in precision press molding. The glass exhibits that a ratio ? (alpha)1/? (alpha)2 is less than 17 when temperature denoting maximum value of differential in amount of elongation of glass relative to temperature differential DELTAT (where DELTAT denotes a constant value of 1° C. or less) over a temperature range from glass transition temperature (Tg) to sag temperature (Ts) is denoted as T1, average coefficient of linear expansion over a range from T1?5° C. to T1+5° C. is denoted as alpha1, and average coefficient of linear expansion over a range from the glass transition temperature (Tg)?160° C. to the glass transition temperature (Tg)?140° C. is denoted as alpha2.

Abstract: Disclosed are a glass substrate for an information recording medium, having excellent scratch resistance and a light weight and having high fracture toughness, the glass substrate having a fragility index value, measured in water, of 12 ?m?1/2 or less or having a fragility index value, measured in an atmosphere having a dew point of ?5° C. or lower, of 7 ?m?1/2 or less, or the glass substrate comprising, by mol %, 40 to 75% of SiO2, 2 to 45% of B2O3 and/or Al2O3 and 0 to 40% of R?2O in which R? is at least one member selected from the group consisting of Li, Na and K), wherein the total content of SiO2, B2O3, Al2O3 and R?2O is at least 90 mol %, and a magnetic information recording medium comprising a magnetic recording layer formed on the glass substrate.

Abstract: An optical glass which has an Abbe's number (?d) of 50 to 59, has the property of not easily reacting with a press mold, a low-temperature softening property, excellent glass stability and high refractivity, and is suitable for precision press-molding. The optical glass comprising B2O3 and SiO2 as essential components and having a B2O3 and SiO2 total content (B2O3+SiO2) of 45 to 70 by mol % and an SiO2 content/B2O3 content molar ratio (SiO2/B2O3) of from 0.1 to 0.5, the optical glass further comprising, by mol %, 5 to 15% of La2O3, 0.1 to 8% of Gd2O3, provided that the total content of La2O3 and Gd2O3 is 8% or more, 0 to 10% of Y2O3, 3 to 18% of Li2O, provided that the molar ratio of the content of Li2O to the total content of B2O3 and SiO2 [Li2O/(B2O3+SiO2)] is over 0 but not more than 0.2, 0.

Abstract: A high-refractivity low-dispersion optical glass that can be stably supplied and has excellent glass stability and that has coloring reduced, comprises, by mass %, 5 to 32% of total of SiO2 and B2O3, 45 to 65% of total of La2O3, Gd2O3 and Y2O3, 0.5 to 10% of ZnO, 1 to 20% of total of TiO2 and Nb2O5, 0 to 15% of ZrO2, 0 to 2% of WO3, 0 to 20% of Yb2O3, 0 to 10% of total of Li2O, Na2O and K2O, 0 to 10% of total of MgO, CaO, SrO and BaO, 0 to 12% of Ta2O5, 0 to 5% of GeO2, 0 to 10% of Bi2O3, and 0 to 10% of Al2O3, wherein the mass ratio of the content of SiO2 to the content of B2O3, (SiO2/B2O3), is from 0.3 to 1.0, and the mass ratio of the total content of Gd2O3 and Y2O3 to the total content of La2O3, Gd2O3 and Y2O3, (Gd2O3+Y2O3)/(La2O3+Gd2O3+Y2O3), is from 0.05 to 0.6, the optical glass having a refractive index nd of 1.89 to 2.0 and an Abbe's number ?d of 32 to 38 and having a coloring degree ?70 of 430 nm or less.

Abstract: The optical glass has a refractive index of equal to or greater than 1.65 and an Abbé number ranging from 50 to 60. In the optical glass, as molar basis, a ratio of SiO2 content to B2O3 content is greater than 0.5 and equal to or less than 0.90; a total content of SiO2 and B2O3 ranges from 50 to 70 percent; Li2O content ranges from 5 to 20 percent; La2O3 content ranges from 0.5 to 22 percent; a ratio of ZnO content to RO (MgO, CaO, SrO and BaO) is equal to or greater than 0.5; a total content of Gd2O3, Y2O3 and Yb2O3 ranges from 1 to 15 percent; Sb2O3 content ranges from 0 to 1 percent; and no BaO is comprised, or a ratio of the total content of La2O3, Gd2O3, Y2O3 and Yb2O3 to the content of BaO is equal to or greater than 10.

Abstract: A low dispersion optical glass comprising, given as molar percentages, 28 to 50 percent of P2O5; more than 20 percent but not more than 50 percent of BaO; 1 to 20 percent MgO; a sum of Li2O, Na2O, and K2O exceeding 3 percent (with 0 to 25 percent of Li2O, greater than or equal to 0 percent and less than 10 percent of Na2O, and 0 to 12 percent of K2O); more than 0 percent but not more than 15 percent of ZnO; 0 to 25 percent of B2O3; 0 to 5 percent of A12O3; 0 to 8 percent of Gd2O3; 0 to 20 percent of CaO; 0 to 15 percent of SrO; and 0 to 1 percent of Sb2O3; with a sum of oxide contents of P, Ba, Mg, Li, Na, K, Zn, B, Al, Gd, Ca, Sr, and Sb being greater than or equal to 98 percent. The optical glass comprises no La2O3. The press molding preform is comprised of the optical glass.

Abstract: A method for manufacturing an optical glass element, comprising: annealing a press-molded product obtained by press molding into a lens shape a glass material comprised of a core portion comprised of an optical glass (first glass) with a transition temperature of 550° C. or higher and a covering portion comprised of a second glass covering the surface of said core portion; and then removing the covering layer from the surface of the press-molded product to obtain an optical glass element. To provide a method for manufacturing high-optical-performance mold-pressed lenses in which the defective external appearance of optical elements comprised of high-temperature glass materials with a Tg of 550° C. or higher is prevented.

Abstract: The present invention has for its objects to provide a method for manufacturing a disklike glass material for the mass production of information recording media substrate-use materials of constant sheet thickness, to provide a method for manufacturing an information recording medium-use substrate from the material thus manufactured, and to provide a method for manufacturing an information recording medium. The provided is a method for manufacturing a disklike glass material comprising the successive molding of multiple pieces of disklike glass material from glass melt. Being suppressed variation over time in the concentration of infrared radiation-absorbing ions contained in the glass melt being molded into said pieces of disklike glass material so that the variation in the sheet thickness of said multiple pieces of disklike glass material falls within a range of ±15 percent of a reference value.

Abstract: [Problems to be Solved] To provide an optical glass having a very high refractive index in spite of its low-dispersion property, having excellent glass stability and having less susceptibility to coloring. [Means to Solve the Problem] An optical glass that is an oxide glass and that comprises, by cationic %, 0 to 30% of Si4+, 10 to 55% of B3+, less than 5% of total of Li+, Na+ and K+, less than 5% of total of Mg2+, Ca2+ and Sr2+, 0 to 8% of Ba2+, 0.1 to 15% of Zn2+, 10 to 50% of La3+, 0 to 20% of Gd3+, 0 to 15% of Y3+, 0 to 10% of Yb3+, 0 to 20% of Zr4+, 0.1 to 22% of Ti4+, 0 to 20% of Nb5+, 0 to 8% of Ta5+, 0 to 5% of W6+, 0 to 8% of Ge4+, 0 to 10% of Bi3+, and 0 to 10% of Ai3+, the cationic ratio of the content of Si4+ to the content of B3+, Si4+/B3+, being less than 1.0, the total content of Nb2O5 and Ta2O5 as oxides being less than 14 mass %, the optical glass having a refractive index nd of 1.92 to 2.2 and an Abbe's number ?d of 25 to 45.