Hoya Corporation

Kazuo Tachiwana

Yoichi Hachitani

Xuelu Zou

Mikio Ikenishi

Kinobu Osakabe

Teruo Yamashita

Hiroaki Yanagita

Yoshiko Kasuga

Junko Akojima

Shigeru Hayashi

Kouichi Sato

Hironori Oguma

A glass article includes P, Al, an alkali earth metal, F and O, wherein the content of P and O is greater at the surface side of the glass article than the inner side thereof and the content of the alkali earth metal and F is less at the surface side of the glass article than the inner side thereof.

Glass article

Provided is a method for manufacturing an optical element from glass after polishing and in which either or both of a cleaning liquid used in a cleaning step for the glass after polishing and a rinsing liquid used in a rinsing step after the cleaning step are a liquid that inhibits expansion of cracked parts present on the surface of the glass after polishing.

Method for manufacturing optical element

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 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 the pieces of disklike glass material so that the variation in the sheet thickness of the multiple pieces of disklike glass material falls within a range of &#xb1;15 percent of a reference value. The reference value being the median between the maximum value and the minimum value of the sheet thickness of 1,000 pieces of the glass material. In the course of molding multiple pieces of disklike glass material comprised of glass containing 0.1 to 100 ppm of infrared radiation-absorbing ions, vaiiation over time in the concentration of the infrared radiation-absorbing contained in the glass melt is suppressed to suppress variation in the sheet thickness of the multiple pieces of sheet like glass material.

Material for information recording medium substrate, information recording medium substrate, information recording medium, and method for manufacturing them

A method of making a press-moldable glass, including melting starting materials, forming a melt, and annealing a formed glass, wherein the melt has a composition such that, (1) when rapidly cooled to room temperature, it becomes glass that has a scattering coefficient of less than 0.005 cmat wavelengths of from 400 to 2,500 nm or comprises crystals with a volumetric ratio of less than 10, and (2) when maintained for three hours at a temperature 10&#xb0; C. higher than the glass transition temperature, maintained for 10 min at a temperature yielding a viscosity of 10to 10dPa&#xb7;s, and then rapidly cooled to room temperature, (3) the resulting glass has (a) a scattering coefficient of at least one wavelength from 400 to 2,500 nm of greater than 0.01 cmor (b) crystals with a volumetric ratio of greater than 10. A temperature for annealing is lower than for glass transition.

Optical glass, glass material for press molding, optical element, and method of manufacturing same

Glass for use in substrate for information recording medium, substrate for information recording medium and information recording medium, and their manufacturing method

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, LaO, YOand 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. Further provided are the substrate for information recording medium, information recording medium and their manufacturing methods according to the present invention.

An on-vehicle camera lens glass material satisfies at least one of conditions in which a measurement result in water resistance based on a powder method prescribed by Japanese Optical Glass Industrial Standard is 1Class, a measurement result in Knoop hardness based on a measurement method prescribed by Japanese Optical Glass Industrial Standard is 6Class or higher, a measurement result in solarization based on a measurement method prescribed by Japanese Optical Glass Industrial Standard is 2% or less, and a measurement result in average linear expansion coefficient based on a measurement method prescribed by Japanese Optical Glass Industrial Standard is 100&#xd7;10&#xb0; C.or less.

On-vehicle camera lens glass material and on-vehicle camera lens

An optical glass having high-refractivity and low-dispersion optical properties and having a low glass transition point so that a heat-treating furnace can be operated for a long period of time. The optical glass has a refractive index nd of at least 1.875, an Abbe's number &#x3bd;d of at least 39.5 and a glass transition point Tg of 700&#xb0; C. or lower, and contains at least one of LaO, GdO, YOor YbOand at least one of ZrO, TaOor NbO, with a weight ratio of the total content of LaO, GdO, YOand YbOto the total content of SiOand BOof from 3.2 to 5 and the weight ratio of the total content of ZrO, TaOand NbOto the total content of SiOand BOis from 1.1 to 1.5.

Optical glass and process for the production of optical products

Disclosed is an optical glass comprising, expressed as weight percentages, greater than or equal to 18 percent and less than 30 percent of SiO, greater than or equal to 12 percent and less than 23 percent of BaO, 22 to 37 percent TiO, greater than or equal to 7 percent and less than 16 percent NbO, 5 to 20 percent of NaO, 0 to 6 percent of KO, 0 to 5 percent of CaO, 0 to 5 percent of SrO, 0 to 4 percent of ZrO, 0 to 3 percent of TaO, 0 to 1 percent of SbO, and greater than or equal to 0 percent and less than 0.5 percent of PO, and by essentially not comprising PbO, AsO, and F. The optical glass exhibits a refractive index (nd) greater than or equal to 1.80 and an Abb&#xe9; number (vd) less than or equal to 30. A method of manufacturing a glass material for press molding is disclosed. This method comprises the steps of melting the glass starting materials, forming the glass melt obtained, and annealing the formed glass and is characterized in that: the glass melt has a composition such that, (1) when rapidly cooled to room temperature, said glass melt becomes glass that has a scattering coefficient of less than 0.005 cmat wavelengths of from 400 to 2,500 nm or comprises crystals with a volumetric ratio of less than 10, and (2) when maintained for three hours at a temperature 10&#xb0; C. higher than the glass transition temperature, maintained for 10 min at a temperature yielding a viscosity of 10to 10dPa&#xb7;s, and then rapidly cooled to room temperature, said glass melt becomes glass that has a scattering coefficient at at least one wavelength from 400 to 2,500 nm of greater than 0.01 cmor comprises crystals with a volumetric ratio of greater than 10; and an annealing of said formed glass is conducted at a temperature lower than the glass transition temperature.

In a light polarization control element using a stress-optical coefficient glass, the stress-optical coefficient glass is substantially composed of a phosphorous acid glass containing 20 to 60 percent by weight of P.sub.2 O.sub.5 and 40 to 73 percent by weight of BaO and PbO.

Light polarization control element using stress-optical coefficient

A highly reliable information recording medium capable of meeting a higher rotation speed of a drive device and a smaller thickness and a higher recording density of an information recording medium can be produced by using, as a substrate, chemically reinforced glass obtained from chemically reinforceable glass having an SiO.sub.2 --Al.sub.2 O.sub.3 --R.sub.2 O total content of more than 98% by weight and having a specific modulus of at least 30.times.10.sup.2.

Information recording medium

A near infrared absorption filter glass containing

Near infrared absorption filter glass

The optical glass of the present invention comprising SiO.sub.2, alkali metal oxides, P.sub.2 O.sub.5 and Nb.sub.2 O.sub.5 has optical properties of 1.70 or more in refractive index nd and 30 or less in Abbe's number .nu.d and is superior in devitrification resistance and stability.

Growing community of inventors

Tokyo, Japan

Kazuo Tachiwana