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公开(公告)号：US11884584B2
公开(公告)日：2024-01-30
申请号：US17895029
申请日：2022-08-24
Applicant: HOYA CORPORATION
Inventor： Koichi Sato , Kazuaki Hashimoto
CPC classification number: C03C3/091 , C03C3/078 , C03C3/083 , C03C3/087 , C03C3/093 , C03C3/095 , G11B5/73921
Abstract: A glass, which is a glass for a magnetic recording medium substrate or for a glass spacer for a magnetic recording and reproducing apparatus, is an amorphous oxide glass. An SiO2 content ranges from 56 mol % to 80 mol %, an Li2O content ranges from 1 mol % to 10 mol %, a B2O3 content ranges from 0 mol % to 4 mol %, a Na2O content is 0 mol %, a total content of MgO and CaO (MgO+CaO) ranges from 9 mol % to 40 mol %, and the oxide glass has a specific gravity of 2.75 g/cm3 or less, a glass transition temperature of 650° C. or higher, and a Young's modulus of 90 GPa or more.
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公开(公告)号：US11551714B2
公开(公告)日：2023-01-10
申请号：US17357281
申请日：2021-06-24
Applicant: HOYA CORPORATION
Inventor： Koichi Sato , Kazuaki Hashimoto
Abstract: A glass for magnetic recording medium substrate is an amorphous oxide glass. In terms of mol %, SiO2 content ranges from 45 to 68%, Al2O3 from 5 to 20%, total content of SiO2 and Al2O3 60 to 80%, B2O3 from 0 to 5%, MgO from 3 to 28%, CaO from 0 to 18%, total content of BaO and SrO 0 to 2%, total content of alkali earth metal oxides from 12 to 30%, total content of alkali metal oxides from 3.5 to 15%, and at least one kind selected from the group made of Sn oxide and Ce oxide being included, a total content of Sn oxide and Ce oxide ranges from 0.05 to 2.00%, a glass transition temperature ≥625° C., a Young's modulus ≥83 GPa, a specific gravity ≤2.85, and an average linear expansion coefficient at 100 to 300° C.≥48×10−7/° C.
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公开(公告)号：US12211533B2
公开(公告)日：2025-01-28
申请号：US18323378
申请日：2023-05-24
Applicant: HOYA CORPORATION
Inventor： Koichi Sato , Kazuaki Hashimoto
Abstract: In an amorphous glass, an SiO2 content is in a range of 56 mol % or more. An MgO content is in a range of 15 mol % or more and 28 mol % or less. An Li2O content is in a range of 0.2 mol % or more. An Na2O content is in a range of 5 mol % or less. A total content of Al2O3, MgO, and CaO (Al2O3+MgO+CaO) is 36.50 mol % or less. The total content of SiO2, MgO, Li2O, Al2O3, and CaO (SiO2+MgO+Li2O+Al2O3+CaO) is 97.5 mol % or more. A mole ratio of the total content of SiO2 and MgO relative to the Li2O content [(SiO2+MgO)/Li2O] is 13 or more. A mole ratio of a CaO content relative to a total content of Al2O3 and MgO [CaO/(Al2O3+MgO)] is 0.10 or less.
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Patent Agency Ranking
公开(公告)号：US12040003B2
公开(公告)日：2024-07-16
申请号：US18075606
申请日：2022-12-06
Applicant: HOYA CORPORATION
Inventor： Koichi Sato , Kazuaki Hashimoto
CPC classification number: G11B5/73921 , C03C3/085 , C03C3/087 , C03C3/091 , C23C14/16 , C23C14/35 , G11B5/658
Abstract: A glass for magnetic recording medium substrate is an amorphous oxide glass. In terms of mol %, SiO2 content ranges from 45 to 68%, Al2O3 from 5 to 20%, total content of SiO2 and Al2O3 60 to 80%, B2O3 from 0 to 5%, MgO from 3 to 28%, CaO from 0 to 18%, total content of BaO and SrO 0 to 2%, total content of alkali earth metal oxides from 12 to 30%, total content of alkali metal oxides from 3.5 to 15%, and at least one kind selected from the group made of Sn oxide and Ce oxide being included, a total content of Sn oxide and Ce oxide ranges from 0.05 to 2.00%, a glass transition temperature ≥625° C., a Young's modulus ≥83 GPa, a specific gravity ≤2.85, and an average linear expansion coefficient at 100 to 300° C.≥48×10−7/° C.
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公开(公告)号：US11688424B2
公开(公告)日：2023-06-27
申请号：US17629002
申请日：2020-07-22
Applicant: HOYA CORPORATION
Inventor： Koichi Sato , Kazuaki Hashimoto
CPC classification number: G11B5/73921 , C03C3/087
Abstract: Provided is a glass for a magnetic recording medium substrate, which is an amorphous glass, in which an SiO2 content is in a range of 54 mol % or more and 62 mol % or less, an MgO content is in a range of 15 mol % or more and 28 mol % or less, an Li2O content is in a range of 0.2 mol % or more, and an Na2O content is in a range of 5 mol % or less.
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公开(公告)号：US11447414B2
公开(公告)日：2022-09-20
申请号：US17055500
申请日：2019-05-14
Applicant: HOYA CORPORATION
Inventor： Koichi Sato , Kazuaki Hashimoto
Abstract: Provided is a glass for a magnetic recording medium substrate, which is an amorphous oxide glass, in which an SiO2 content ranges from 56 mol % to 80 mol %, an Li2O content ranges from 1 mol % to 10 mol %, a B2O3 content ranges from 0 mol % to 4 mol %, a total content of MgO and CaO (MgO+CaO) ranges from 9 mol % to 40 mol %, and the oxide glass has a specific gravity of 2.75 g/cm3 or less, a glass transition temperature of 650° C. or higher, and a Young's modulus of 90 GPa or more.
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公开(公告)号：US11081133B2
公开(公告)日：2021-08-03
申请号：US16349795
申请日：2017-11-14
Applicant: HOYA CORPORATION
Inventor： Koichi Sato , Kazuaki Hashimoto
Abstract: A glass for magnetic recording medium substrate is an amorphous oxide glass. In terms of mol %, SiO2 content ranges from 45 to 68%, Al2O3 from 5 to 20%, total content of SiO2 and Al2O3 60 to 80%, B2O3 from 0 to 5%, MgO from 3 to 28%, CaO from 0 to 18%, total content of BaO and SrO 0 to 2%, total content of alkali earth metal oxides from 12 to 30%, total content of alkali metal oxides from 3.5 to 15%, and at least one kind selected from the group made of Sn oxide and Ce oxide being included, a total content of Sn oxide and Ce oxide ranges from 0.05 to 2.00%, a glass transition temperature ≥625° C., a Young's modulus ≥83 GPa, a specific gravity ≤2.85, and an average linear expansion coefficient at 100 to 300° C.≥48×10−7/° C.
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公开(公告)号：US11999652B2
公开(公告)日：2024-06-04
申请号：US17784528
申请日：2020-12-11
Applicant: HOYA CORPORATION
Inventor： Koichi Sato , Kazuaki Hashimoto
Abstract: Provided is a glass for a magnetic recording medium substrate or for a glass spacer for a magnetic recording/reproducing apparatus, in which the total content of Li2O, Na2O, K2O, B2O3, and ZnO (Li2O+Na2O+K2O+B2O3+ZnO) is in a range of 0 mol % or more and 3 mol % or less, the mole ratio of the total content of Al2O3 and MgO relative to the total content of SiO2 and CaO [(Al2O3+MgO)/(SiO2+CaO)] is in a range of 0.30 or more and 0.6 or less, the total content of SiO2 and Al2O3 (SiO2+Al2O3) is in a range of 64 mol % or more and 85 mol % or less, and the total content of SiO2, Al2O3, MgO, and CaO (SiO2+Al2O3+MgO+CaO) is in a range of 87 mol % or more and 98 mol % or less.
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