Hoya Corporation

Mikio Ikenishi

Xuelu Zou

Kinobu Osakabe

Yoshitake Tanno

Yoichi Hachitani

Kazuo Tachiwana

Atsuko Morita

Shinji Eda

Junichi Horikawa

Kenji Yamanaka

Hideki Isono

Isao Tanaka

Yoshiko Kasuga

Naomi Matsumoto

Katsuyuki Iwata

Akihiro Shoji

The glass substrate having opposing flat two main surfaces includes a plurality of optically homogeneous glass pieces joined with one another, in which a junction surface between the joined glass pieces is perpendicular or substantially perpendicular with respect to the two main surfaces.

Glass substrate, method of manufacturing glass substrate, and method of manufacturing glass element using glass substrate

[Problem] To provide glass having a colored layer. [Solution] Glass having a colored layer.

Glass including a small-transmittance portion and a large-transmittance portion

A ring-shaped glass spacer is configured to be arranged in contact with a magnetic disk in a hard disk drive apparatus. A surface resistivity of a surface of a glass material of the glass spacer at 22 (&#xb0; C.) is lower than a surface resistivity of an inner portion of the glass material at 22 (&#xb0; C.).

Glass spacer, hard disk drive apparatus, and method for manufacturing glass spacer

A glass material of a glass spacer has a surface resistivity of 10to 10(&#x3a9;/sq) at 22 (&#xb0; C.). The surface resistivity of a surface of the glass material of the glass spacer at 22 (&#xb0; C.) is lower than the surface resistivity of an inner portion of the glass material at 22 (&#xb0; C.). The glass spacer contains at least one oxide selected from the group consisting of TiO, NbO, WO, and BiO, as a glass component.

A glass lens blank for polishing in which a thickness of a defect-containing layer is suppressed to a minimum and thus it is possible to shorten the processing time required for grinding and polishing the glass lens blank for polishing after press-molding, a method of manufacturing the same, and a method of manufacturing an optical lens. A glass lens blank for polishing of which at least a main surface is a press-molding surface, wherein a defect-containing layer formed on the main surface has a thickness of 50 &#x3bc;m or less.

Glass lens blank for polishing, manufacturing method therefore, and optical lens manufacturing method

To provide a fluorophosphates glass having a weather-resistant property and having an O/Pratio even after production, which is set so that Cucan be added with a quantity of such a degree suppressing an absorption of a visible light while absorbing a near-infrared light, and a method for producing the same, and a near-infrared light absorbing filter, wherein a molar ratio of a content of Owith respect to a content of P(O/P) in the fluorophosphates glass, is 3.2 or more and less than 3.4, and a molar ratio of a content of Fwith respect to a total content of Oand F(F/(O+F)) in the fluorophosphates glass is 0.05 or more and 0.25 or less.

Fluorophosphate glass and method for producing the same and near-infrared absorbing filter

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 SiOand AlO, where SiOcontent is equal to or greater than 50 percent and AlOcontent is equal to or greater than 3 percent; a total of equal to or greater than 10 percent of LiO, NaO and KO; 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 ZrO, HfO, NbO, TaO, LaOYOand TiO; with the molar ratio of the total content of LiO, NaO and KO to the total content of SiO, AlO, ZrO, HfO, NbO, TaO, LaO, YOand TiO((LiO+NaO+KO)/(SiO+AlO+ZrO+HfO+NbO+TaO+LaO+YO+TiO)) being equal to or less than 0.28. Further provided are the substrate for information recording medium, information recording medium and their manufacturing methods according to the present invention.

Glass for use as substrate for information recording medium, substrate for information recording medium and information recording medium, and their production methods

A glass for use in chemical reinforcement for use in a substrate of an information recording medium, having a composition comprising, denoted as mol %: 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&#xb0; C. A substrate for use in an information recording medium consisting of the above glass and being chemically reinforced. A substrate for an information recording medium consisting of a chemically reinforced glass having a glass transition temperature of greater than or equal to 600&#xb0; C. and exhibiting a bending strength following heating for two hours at 570&#xb0; C. of greater than or equal to 15 kgf/mm. An information recording medium comprising an information recording layer on the above substrate for an information recording medium. The present invention provides glass having both high thermal resistance and high strength, a substrate for use in information recording media comprised of this glass, and an information recording medium employing such a substrate.

Glass for chemical strengthening, substrate for information recording media and information recording media

In order to produce a fluorophosphate glass including Pat a small content on the composition thereof, the composition is adjusted so as to provide well-balanced chemical durability and thermal stability. In the production of a fluorophosphate glass in which O/P&#x3e;3.7, Alcontent is in a predetermined amount or more and pcontent is in a predetermined amount or less, a glass raw material is prepared by using an AlFin which the content of AlOis limited to the range from 1 to 5% by mass, and the raw material is melted to produce the fluorophosphate glass.

Method for producing fluorophosphate glass, glass material for press molding and optical element

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 &#x3bc;mor less or having a fragility index value, measured in an atmosphere having a dew point of &#x2212;5&#xb0; C. or lower, of 7 &#x3bc;mor less, or the glass substrate comprising, by mol %, 40 to 75% of SiO, 2 to 45% of BOand/or AlOand 0 to 40% of R'O in which R&#x2032; is at least one member selected from the group consisting of Li, Na and K), wherein the total content of SiO, BO, AlOand R&#x2032;O is at least 90 mol %, and a magnetic information recording medium comprising a magnetic recording layer formed on the glass substrate.

Glass substrate for information recording medium and magnetic information recording medium to which the glass substrate is applied

An aspect of the present invention relates to a glass substrate for a magnetic recording medium, which is comprised of glass with a glass transition temperature of equal to or greater than 600&#xb0; C., an average coefficient of linear expansion at 100 to 300&#xb0; C. of equal to or greater than 70&#xd7;10/&#xb0; C., a Young's modulus of equal to or greater than 81 GPa, a specific modulus of elasticity of equal to or greater than 30 MNm/kg, and a fracture toughness value of equal to or greater than 0.9 MPa&#xb7;m.

Glass substrate for magnetic recording medium and its use

The present invention provides a fluorophosphate glass containing more than 3 cationic % and 30 cationic % or less of a phosphorus ingredient in terms of P, the glass having a ratio I/Iof equal to or less than 0.08 in which Iis a strength of a resonance peak generated near a reference frequency ofP in a nuclear magnetic resonance spectrum and Iis a strength of a first-order side band peak of the resonance peak. The glass of the invention is reduced in volatility and erosiveness.

Fluorophosphate glass, precision press molding preform, optical element blank, optical element and method of manufacturing the same

The present invention provides a fluorophosphate glass containing 30 to 50 cationic % of a phosphorus ingredient in terms of P, the glass having, in a nuclear magnetic resonance spectrum, a resonance spectrum which is generated near a reference frequency ofP and has a shape of Gaussian function. The glass of the invention is reduced in volatility and erosiveness.

Fluorophosphate glass, precision press molding preform, optical element blank, optical element and methods of manufacturing the same

The present invention provide a fluorophosphate glass comprising 3 to 25 cation % of P, more than 30 cation % and 40 cation % or less of Al, 0.5 to 20 cation % of Liand 65 anion % or more of Fas glass ingredients, and having a liquid phase temperature of 700&#xb0; C. or less. The fluorophosphate glass of the present invention has ultra low dispersibility and stability, and is preferably used for glass materials for press molding, optical element blanks and optical elements.

Fluorophosphate glass, glass material for press molding, optical element blank, optical element, processes for production of same, and process for production of glass moldings

Growing community of inventors

Tokyo, Japan

Mikio Ikenishi