Hoya Corporation

Naomi Matsumoto

Kazuaki Hashimoto

Kinobu Osakabe

Yoshitake Tanno

Yutaka Takakubo

Toshiki Nakamura

Yoichi Hachitani

Koichi Sato

Masaru Eguchi

Mikio Ikenishi

Hideki Isono

Kosuke Yamaguchi

Katsuyuki Iwata

Yasushi Tsutsumi

Provided is oxide glass in which a content of Pis 7 to 43 cation %, a content of Nb ions is 10 to 21 cation %, a content of Liis 20 cation % or more, a total content of Nb ions and Liis 48 to 70 cation %, a content of Bi ions is more than 0 cation % and is equal to or less than 6 cation %, a content of Bais 5 cation % or less, a content of Zris 2 cation % or less, a total content of Ti ions and W ions is 5 cation % or less, and a cation ratio of the content of Lito a total content of Li, Na, and K[Li/(Li+Na+K)] is 0.5 or more.

Glass and optical element

An optical element includes a glass body including a colored layer provided inside the glass body and positioned at an optical function surface of the optical element. An optical apparatus including the optical element is also provided.

Optical element and optical apparatus

An optical element including a glass body is provided. The optical element includes a colored layer provided inside the glass body and positioned outside an effective aperture of the optical element. Coloring of the colored layer is a reduction pigment occurring in a glass component of the glass body. The colored layer suppresses occurrence of stray light and obtains sufficient light-shielding properties, so that a superior image quality can be achieved.

An aspect of the present invention relates to glass for a magnetic recording medium substrate, which includes essential components in the form of SiO, LiO, NaO, and one or more alkaline earth metal oxides selected from the group consisting of MgO, CaO, SrO, and BaO, wherein a molar ratio of a content of MgO to a combined content of MgO, CaO, SrO, and BaO (MgO/(MgO+CaO+SrO+BaO)) is equal to or greater than 0.80, and which has a Young's modulus of equal to or greater than 80 GPa, and a glass transition temperature of equal to or greater than 620&#xb0; C.

Glass for magnetic recording medium substrate and usage thereof

An aspect of the present invention relates to glass for a magnetic recording medium substrate, which comprises essential components in the form of SiO, LiO, NaO, and one or more alkaline earth metal oxides selected from the group consisting of MgO, CaO, SrO, and BaO wherein a molar ratio of a content of CaO to a combined content of MgO, CaO, SrO, and BaO (CaO/(MgO+CaO+SrO+BaO)) is equal to or less than 0.20, and which has a glass transition temperature of equal to or higher than 650&#xb0; C.

Glass for magnetic recording medium substrate, glass substrate for magnetic recording medium, and their use

An aspect of the present invention relates to an optical glass, which comprises, denoted as weight percent, 2 to 37 percent of SiO, 0 to 25 percent of BO, 0 to 10 percent of GeO, 18 to 55 percent of a combined content of LiO, NaO, KO, CaO, SrO, and BaO, and 27 to 55 percent of a combined content of TiO, NbO, and WO, wherein the weight ratio of SiOcontent relative to a combined content of SiOand BOranges from 0.1 to 1, a weight ratio of the LiO content to a combined content of LiO, NaO, KO, CaO, SrO, and BaO ranges from 0 to 0.4, and a weight ratio of TiOcontent relative to a combined content of TiO, NbO, and WOranges from 0.35 to 1, with a refractive index nd of 1.860 to 1.990 and an Abb&#xe9; number &#x3bd;d of 21 to 29.

Optical glass, press-molding glass material, optical element and method of manufacturing the same, and bonded optical element

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

An aspect of the present invention relates to glass for a magnetic recording medium substrate, which comprises, denoted as molar percentages, 50 to 75 percent of SiO, 0 to 5 percent of AlO, 0 to 3 percent of LiO, 0 to 5 percent of ZnO, a total of NaO and KO of 3 to 15 percent, a total of MgO, CaO, SrO, and BaO of 14 to 35 percent, a total of ZrO, TiO, LaO, YO, YbO, TaO, NbO, and HfOof 2 to 9 percent, with a molar ratio of {(MgO+CaO)/(MgO+CaO+SrO+BaO)} falling within a range of 0.85 to 1, and a molar ratio of {AlO/(MgO+CaO)} falling within a range of 0 to 0.30.

Glass for magnetic recording medium substrate, magnetic recording medium substrate and method of manufacturing the same, and magnetic recording medium

The present invention relates to recording glass substrates molar percentages: 56-75 SiO, 1-11 AlO, more than 0-4 LiO, 1-15 NaO. more than 0 less than 3 KO, no BaO. total LiO, NaO and KO 6-15, (LiO NaO) less than 0.50, {KO/(LiO, NaO and KO)} equal or less than 0.13, total MgO, CaO and SrO 10-30, MgO and CaO 10-30, {(MgO+CaO)/(MgO+CaO+SrO)} equal or more than 0.86, alkali oxides to alkaline earth oxides equal to or more than 0.50. total ZrO, TiO, YO, LaO, GdO, NbO, and TaOmore than 0 equal to or less than 10, molar ratio {(ZrO, TiO, YO, LaO, GdO, NbO, and TaO)/AlOequal or more than 0.40, Tg equal to or higher than 600&#xb0; C., average coefficient linear expansion equal or higher than 70&#xd7;10/&#xb0;C. at 100-300&#xb0; C. and Young's modulus equal to or higher than 80 GPa.

Growing community of inventors

Shinjuku-ku, Japan

Naomi Matsumoto