公开(公告)号：US20210264946A1

公开(公告)日：2021-08-26

申请号：US17315109

申请日：2021-05-07

Applicant: HOYA CORPORATION

Inventor： Shinji EDA ,  Kinobu OSAKABE ,  Yoshitake TANNO ,  Mikio IKENISHI

IPC: G11B17/32 ,  G11B5/73 ,  G11B17/038 ,  G11B33/12

Abstract: 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 (° C.) is lower than a surface resistivity of an inner portion of the glass material at 22 (° C.).

公开(公告)号：US20240296867A1

公开(公告)日：2024-09-05

申请号：US18665368

申请日：2024-05-15

Applicant: HOYA CORPORATION

Inventor： Shinji EDA

IPC: G11B5/73

CPC classification number: G11B5/73921 ,  G11B5/73911 ,  G11B5/73917 ,  G11B5/73919

Abstract: A substrate for a magnetic disk has a disk shape. The substrate has a diameter D of 85 mm or more and 100 mm or less, and a thickness T of 0.3 mm or more and 0.5 mm or less. Regarding a Young's modulus E and the thickness T of the substrate, a value of E·T3 is 3 to 18 (GPa·mm3). A material of the substrate has a Q-value of 1500 or less under conditions of 3000 Hz and room temperature.

公开(公告)号：US20230253012A1

公开(公告)日：2023-08-10

申请号：US18194619

申请日：2023-04-01

Applicant: HOYA CORPORATION

Inventor： Shinji EDA

IPC: G11B5/73

CPC classification number: G11B5/73921 ,  G11B5/73911 ,  G11B5/73919 ,  G11B5/73917

Abstract: A substrate for a magnetic disk has a disk shape. The substrate has a diameter D of 85 mm or more and a thickness T of 0.6 mm or less. When an impact is applied to the substrate under conditions of 70 (G) and 2 (msec) in a normal direction of main surfaces of the substrate in a state in which an inner circumferential end portion of the substrate is fixed, the maximum amplitude of vibration in a thickness direction of an outer circumferential end portion of the substrate is 0.25 mm or less, the substrate is a non-magnetic metal substrate, and regarding the Young's modulus E and the thickness T of the substrate, a value of E·T3 is 3 to 18 (GPa·mm3).

公开(公告)号：US20240062779A1

公开(公告)日：2024-02-22

申请号：US18259773

申请日：2021-12-28

Applicant: HOYA CORPORATION ,  HOYA GLASS DISK VIETNAM II LTD.

Inventor： Shinji EDA ,  Kenichi NISHIMORI

IPC: G11B5/84 ,  G11B5/82 ,  G11B5/73

CPC classification number: G11B5/84 ,  G11B5/82 ,  G11B5/73

Abstract: A magnetic disk used in a hard disk drive device includes a substrate; a magnetic recording layer; and a heat insulating layer provided between the substrate and the magnetic recording layer. Even though a substrate has low heat resistance, as a result of providing the heat insulating layer, the substrate can be used as a substrate for a magnetic disk that can withstand heat treatment (high-temperature annealing).

公开(公告)号：US20210256999A1

公开(公告)日：2021-08-19

申请号：US17266079

申请日：2019-08-07

Applicant: HOYA CORPORATION

Inventor： Shinji EDA

IPC: G11B5/73

Abstract: A disk-shaped substrate for a magnetic disk has a diameter D of 85 mm or more and a thickness T of 0.6 mm or less, and a material of the substrate has a Young's modulus E of 90 GPa or more.

公开(公告)号：US20150199989A1

公开(公告)日：2015-07-16

申请号：US14667641

申请日：2015-03-24

Applicant: HOYA CORPORATION

Inventor： Shinji EDA ,  Hideki ISONO

IPC: G11B5/735 ,  C03B11/08 ,  B24B1/00 ,  C03C19/00

CPC classification number: G11B5/735 ,  B24B1/00 ,  C03B11/088 ,  C03B2215/44 ,  C03C19/00 ,  G11B5/8404 ,  Y10T428/24355

Abstract: The present invention provides a glass substrate for magnetic disk in which surface irregularity of a principal surface is suppressed and a method for efficiently manufacturing a glass substrate for magnetic disk. The method includes the steps of: forming a sheet glass material by performing press forming to molten glass, a principal surface of the sheet glass material having target flatness for the glass substrate for magnetic disk, the sheet glass material having a surface shape to be ground using a grinding abrasive grain; grinding the sheet glass material using a fixed abrasive grain; and polishing the sheet glass material using a loose abrasive grain, the sheet glass material having surface irregularity of the principal surface ground using the fixed abrasive grain.

Abstract translation: 本发明提供了一种用于抑制主面的表面不规则性的磁盘用玻璃基板和有效地制造磁盘用玻璃基板的方法。 该方法包括以下步骤：通过对熔融玻璃进行压制成形来形成玻璃板材料，对于具有用于磁盘的玻璃基板的目标平面度的玻璃板材料的主表面，具有待研磨的表面形状的玻璃板材料 使用研磨磨粒; 用固定的磨粒研磨平板玻璃材料; 并且使用松散的磨粒抛光玻璃板材料，该玻璃板材料使用固定的磨料颗粒具有主表面磨削的表面不规则性。

公开(公告)号：US20140287269A1

公开(公告)日：2014-09-25

申请号：US14299881

申请日：2014-06-09

Applicant: HOYA CORPORATION

Inventor： Shinji EDA ,  Hideki ISONO ,  Takashi MAEDA ,  Hiroshi TSUCHIYA ,  Yoshinori MARUMO

IPC: G11B5/73

CPC classification number: C03C23/009 ,  C03C19/00 ,  C03C21/008 ,  C03C23/0075 ,  C03C2204/08 ,  C09G1/02 ,  G11B5/7315 ,  G11B5/8404 ,  G11B5/8408

Abstract: Provided are a magnetic disk substrate and a method of manufacturing the same, wherein the magnetic disk substrate has very few defects present on its surface with an arithmetic mean roughness (Ra) at a level in the vicinity of 0.1 nm and thus is suitable as a substrate for a magnetic disk with high recording density. The magnetic disk glass substrate is such that the arithmetic mean roughness (Ra) of the main surface of the glass substrate measured using an atomic force microscope with a resolution of 256×256 pixels in a 2 μm×2 μm square is 0.12 nm or less and the number of defects detected to have a size of 0.1 μm to 0.6 μm in plan view and a depth of 0.5 nm to 2 nm is less than 10 per 24 cm2, wherein the defects are each detected using a shift in wavelength between incident light and reflected light upon irradiating and scanning helium neon laser light with a wavelength of 632 nm on the main surface of the glass substrate.

Abstract translation: 提供一种磁盘基板及其制造方法，其中，磁盘基板的表面上存在极少的缺陷，算术平均粗糙度（Ra）在0.1nm附近，因此适合作为 具有高记录密度的磁盘的基板。 磁盘玻璃基板使用原子力显微镜在2μm×2μm的正方形中以256×256像素的分辨率测量的玻璃基板的主面的算术平均粗糙度（Ra）为0.12nm以下 并且在平面图中检测为具有0.1μm至0.6μm的尺寸和0.5nm至2nm的深度的缺陷的数量小于每24cm 2的10个，其​​中每个使用入射光之间的波长偏移检测缺陷 并在玻璃基板的主表面上照射和扫描波长为632nm的氦氖激光的反射光。

公开(公告)号：US20220157340A1

公开(公告)日：2022-05-19

申请号：US17589824

申请日：2022-01-31

Applicant: HOYA CORPORATION

Inventor： Masao TAKANO ,  Shinji EDA

IPC: G11B17/02 ,  G11B17/038

Abstract: A method for manufacturing the ring-shaped glass spacer to be arranged in contact with a magnetic disk in a hard disk drive apparatus, including: preparing a ring-shaped glass blank; and grinding main surfaces of the ring-shaped glass blank by using grinding pads that include diamond particles as fixed abrasive particles.

公开(公告)号：US20200227087A1

公开(公告)日：2020-07-16

申请号：US16641399

申请日：2019-01-31

Applicant: HOYA CORPORATION

Inventor： Shinji EDA ,  Kinobu OSAKABE ,  Yoshitake TANNO ,  Mikio IKENISHI

IPC: G11B17/32 ,  G11B5/73 ,  G11B33/12 ,  G11B17/038

Abstract: A glass material of a glass spacer has a surface resistivity of 103 to 109 [Ω/sq] at 22 [° C.]. The surface resistivity of a surface of the glass material of the glass spacer at 22 [° C.] is lower than the surface resistivity of an inner portion of the glass material at 22 [° C.]. The glass spacer contains at least one oxide selected from the group consisting of TiO2, Nb2O5, WO3, and Bi2O3, as a glass component.

公开(公告)号：US20200211596A1

公开(公告)日：2020-07-02

申请号：US16634128

申请日：2018-10-01

Applicant: HOYA CORPORATION

Inventor： Masao TAKANO ,  Shinji EDA

IPC: G11B17/02 ,  G11B17/038

Abstract: In order to suppress the occurrence of adhesion between magnetic disks and spacers when the magnetic disks and the spacers are removed from a hard disk drive apparatus in which the magnetic disks and the spacers are installed, a surface roughness Ra of a main surface of a ring-shaped glass spacer to be arranged in contact with a magnetic disk is set to be not larger than 1.0 μm, and an average inclination RΔa of the main surface is set to be at least 0.02.