公开(公告)号：US20220277768A1

公开(公告)日：2022-09-01

申请号：US17629002

申请日：2020-07-22

Applicant: HOYA CORPORATION

Inventor： Koichi SATO ,  Kazuaki HASHIMOTO

IPC: G11B5/73 ,  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.

公开(公告)号：US20240286946A1

公开(公告)日：2024-08-29

申请号：US18655216

申请日：2024-05-03

Applicant: HOYA CORPORATION

Inventor： Koichi SATO ,  Kazuaki HASHIMOTO

IPC: C03C3/095 ,  C03C3/087 ,  G11B5/235 ,  G11B5/72

CPC classification number: C03C3/095 ,  C03C3/087 ,  G11B5/235 ,  G11B5/72

Abstract: Provided is a glass for a magnetic recording medium substrate or for a glass spacer for a magnetic recording/reproducing apparatus, in which a mole ratio of the total content of Al2O3and MgO relative to the total content of SiO2 and CaO [(Al2O3+MgO)/(SiO2+CaO)] is in a range of 0.417 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, 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, the Na2O content is 0 mol %, and an average linear expansion coefficient of the glass at 100° C. to 300° C. is 68×10−7/° C. or less.

公开(公告)号：US20240158281A1

公开(公告)日：2024-05-16

申请号：US18548890

申请日：2022-03-04

Applicant: HOYA CORPORATION

Inventor： Shuzo TOKUMITSU ,  Kazuaki HASHIMOTO

IPC: C03C3/085 ,  C03C3/091 ,  C03C3/095 ,  G11B5/73

CPC classification number: C03C3/085 ,  C03C3/091 ,  C03C3/095 ,  G11B5/73921

Abstract: Provided is a glass for a magnetic recording medium substrate or for a glass spacer for a magnetic recording/reproducing device, the glass being an amorphous glass that contains at least Li2O, in which a total content of Na2O and K2O is 0 mol % or more and 6.0 mol % or less, a B2O3 content is 0 mol % or more and 10.0 mol % or less, and a CaO content is 0 mol % or more and 1.0 mol % or less.

公开(公告)号：US20150191394A1

公开(公告)日：2015-07-09

申请号：US14661840

申请日：2015-03-18

Applicant: AvanStrate Inc. ,  HOYA CORPORATION

Inventor： Akihiro KOYAMA ,  Mikiko MORISHITA ,  Satoshi AMI ,  Kazuaki HASHIMOTO ,  Tetsuo TAKANO

IPC: C03C21/00 ,  C03C3/083 ,  C03C3/085 ,  C03C15/02 ,  C03C3/087

CPC classification number: C03C21/002 ,  C03C3/083 ,  C03C3/085 ,  C03C3/087 ,  C03C15/00 ,  C03C15/02

Abstract: The disclosed cover glass is produced by etching a glass substrate that has been formed by a down-drawing process, and chemically strengthening the glass substrate to provide the glass substrate with a compressive-stress layer on the principal surfaces thereof. The glass substrate contains, as components thereof, 50% to 70% by mass of SiO2, 5% to 20% by mass of Al2O3, 6% to 30% by mass of Na2O, and 0% to less than 8% by mass of Li2O. The glass substrate may also contain 0% to 2.6% by mass of CaO, if necessary. The glass substrate has an etching characteristic in which the etching rate is at least 3.7 μm/minute in an etching environment having a temperature of 22° C. and containing hydrogen fluoride with a concentration of 10% by mass.

Abstract translation: 所公开的盖玻璃通过蚀刻通过下拉法形成的玻璃基板，并化学强化玻璃基板，以在玻璃基板的主表面上提供压应力层来制造。 玻璃基板作为其成分含有50〜70质量％的SiO 2，5〜20质量％的Al 2 O 3，6〜30质量％的Na 2 O，0〜8质量％ Li2O。 如果需要，玻璃基板也可以含有0〜2.6质量％的CaO。 玻璃基板具有蚀刻特性，其中在温度为22℃的蚀刻环境中蚀刻速率至少为3.7μm/分钟，并且含有浓度为10质量％的氟化氢。

公开(公告)号：US20130343166A1

公开(公告)日：2013-12-26

申请号：US13839484

申请日：2013-03-15

Applicant: HOYA CORPORATION

Inventor： Naomi MATSUMOTO ,  Kazuaki HASHIMOTO

IPC: G11B5/73

CPC classification number: G11B5/7315 ,  G11B5/8404 ,  Y10T428/24355 ,  Y10T428/315

Abstract: An aspect of the present invention relates to glass for a magnetic recording medium substrate, which comprises essential components in the form of SiO2, Li2O, Na2O, 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° C.

Abstract translation: 本发明的一个方面涉及一种用于磁记录介质基板的玻璃，其包括SiO 2，Li 2 O，Na 2 O以及一种或多种选自MgO，CaO，SrO等的一种或多种碱土金属氧化物的主要成分， 和BaO，其中CaO的含量与MgO，CaO，SrO和BaO（CaO /（MgO + CaO + SrO + BaO）的组合含量）的摩尔比等于或小于0.20，并且具有玻璃 转变温度等于或高于650℃

公开(公告)号：US20240290350A1

公开(公告)日：2024-08-29

申请号：US18572677

申请日：2022-07-05

Applicant: HOYA CORPORATION

Inventor： Kazuaki HASHIMOTO ,  Masanori TAMAKI

IPC: G11B5/73 ,  C03B25/02

CPC classification number: G11B5/73921 ,  C03B25/025

Abstract: A glass plate is a rectangular plate having a thickness less than 0.68 mm. A square measurement region having a length of 100 mm per side and cut out from a central region of the glass plate has a degree of flatness of 30 μm or less. When subjected to first heat treatment in which the measurement region is kept at 700° C. for 4 hours and then cooled from 700° C. to 400° C. at a rate of 50° C./hour, the measurement region has a thermal contraction rate of 130 ppm or less. When subjected to second heat treatment in which the measurement region is kept at Tg-160° C. for 60 seconds and then cooled to room temperature in ambient air, where Tg (° C.) represents a glass transition temperature of the glass plate, an amount of change in the degree of flatness of the measurement region is 10 μm or less.

公开(公告)号：US20240071419A1

公开(公告)日：2024-02-29

申请号：US18494381

申请日：2023-10-25

Applicant: HOYA CORPORATION

Inventor： Masafumi MIURA ,  Kazuaki HASHIMOTO ,  Naoyuki HIGUCHI

IPC: G11B17/02 ,  G11B5/73 ,  G11B23/03

CPC classification number: G11B17/021 ,  G11B5/73921 ,  G11B23/03

Abstract: A ring-shaped glass spacer is to be arranged in contact with a magnetic disk in a hard disk drive device. A film that contains at least one of tin oxide, zinc oxide, and titanium oxide is formed on each surface of a main surface, and an outer circumferential edge surface, and an inner circumferential edge surface of the glass spacer. The thickness of the film on a center portion of the outer circumferential edge surface of the glass spacer is larger than the thickness of the film on a center portion of the inner circumferential edge surface of the glass spacer.

公开(公告)号：US20230306996A1

公开(公告)日：2023-09-28

申请号：US18323378

申请日：2023-05-24

Applicant: HOYA CORPORATION

Inventor： Koichi SATO ,  Kazuaki HASHIMOTO

IPC: G11B5/73 ,  C03C3/087

CPC classification number: G11B5/73921 ,  C03C3/087

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, Li20, Al2O3, and CaO (SiO2 + MgO + Li20 + 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.

公开(公告)号：US20230223047A1

公开(公告)日：2023-07-13

申请号：US17909583

申请日：2021-03-08

Applicant: HOYA CORPORATION

Inventor： Masafumi MIURA ,  Kazuaki HASHIMOTO ,  Naoyuki HIGUCHI

IPC: G11B17/02 ,  G11B5/73 ,  G11B23/03

CPC classification number: G11B17/021 ,  G11B5/73921 ,  G11B23/03

Abstract: A method for manufacturing a ring-shaped glass spacer to be arranged in contact with a magnetic disk in a hard disk drive device includes processing for forming a film on the surface of a glass spacer main body, which is the base of the glass spacer. In the processing, the film is formed by passing the glass spacer main body through a location where the components of the film are in a spray state while an outer circumferential edge surface of the glass spacer main body is being rotated in a circumferential direction thereof.

公开(公告)号：US20230103236A1

公开(公告)日：2023-03-30

申请号：US18075606

申请日：2022-12-06

Applicant: HOYA CORPORATION

Inventor： Koichi SATO ,  Kazuaki HASHIMOTO

IPC: G11B5/73 ,  C03C3/087 ,  C03C3/091 ,  G11B5/65 ,  C03C3/085 ,  C23C14/16 ,  C23C14/35

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.