公开(公告)号：US11694718B2

公开(公告)日：2023-07-04

申请号：US17472567

申请日：2021-09-10

申请人： HOYA CORPORATION

发明人： Kinobu Osakabe

IPC分类号： G11B5/73

CPC分类号： G11B5/73921 ,  G11B5/739 ,  G11B5/73911 ,  G11B5/73917 ,  G11B5/73919

摘要： A substrate for a magnetic disk includes a substrate main body having two main surfaces and an outer circumferential edge surface that has a side wall surface and chamfered surfaces, and a film that is an alloy film containing Ni and P and provided on a surface of the substrate main body. A disk shape of the substrate main body has an outer diameter of 90 mm or more. A thickness T of the substrate that includes the film provided on the main surfaces is 0.520 mm or less. A total thickness D mm of the film on the main surfaces and the thickness T mm satisfy D≥0.0082/T−0.0015. A film thickness of the film on the outer circumferential edge surface is larger than a film thickness of the film on the main surfaces, and is 150% or less of the film thickness of the film on the main surfaces.

公开(公告)号：US20230298623A1

公开(公告)日：2023-09-21

申请号：US18321166

申请日：2023-05-22

申请人： HOYA CORPORATION

发明人： Kinobu OSAKABE

IPC分类号： G11B5/73

CPC分类号： G11B5/73921 ,  G11B5/739 ,  G11B5/73911 ,  G11B5/73917 ,  G11B5/73919

摘要： A substrate for a magnetic disk includes a substrate main body having two main surfaces and an outer circumferential edge surface, and a film that is an alloy film containing Ni and P and provided on a surface of the substrate main body. A disk shape of the substrate main body has an outer diameter of 90 mm or more. A thickness T of the substrate that includes film thicknesses of sections of the film provided on the main surfaces is 0.520 mm or less. A total thickness D mm, which is a sum of the film thicknesses of the sections of the film on the main surfaces and the thickness T mm satisfy D≥0.0082/T−0.0015. A surface roughness maximum height Rz of the film provided on the outer circumferential edge surface is smaller than that of the substrate main body at the outer circumferential edge surface.

公开(公告)号：US20240296867A1

公开(公告)日：2024-09-05

申请号：US18665368

申请日：2024-05-15

申请人： HOYA CORPORATION

发明人： Shinji EDA

IPC分类号： G11B5/73

CPC分类号： G11B5/73921 ,  G11B5/73911 ,  G11B5/73917 ,  G11B5/73919

摘要： 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

申请人： HOYA CORPORATION

发明人： Shinji EDA

IPC分类号： G11B5/73

CPC分类号： G11B5/73921 ,  G11B5/73911 ,  G11B5/73919 ,  G11B5/73917

摘要： 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：US12020735B2

公开(公告)日：2024-06-25

申请号：US18194619

申请日：2023-04-01

申请人： HOYA CORPORATION

发明人： Shinji Eda

IPC分类号： G11B5/73

CPC分类号： G11B5/73921 ,  G11B5/73911 ,  G11B5/73917 ,  G11B5/73919

摘要： 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：US20240170015A1

公开(公告)日：2024-05-23

申请号：US18284685

申请日：2022-03-31

申请人： SONY GROUP CORPORATION

发明人： Noboru SEKIGUCHI ,  Minoru YAMAGA

IPC分类号： G11B5/78 ,  G11B5/706 ,  G11B5/73 ,  G11B23/087 ,  G11B23/107

CPC分类号： G11B5/78 ,  G11B5/70615 ,  G11B5/70678 ,  G11B5/73911 ,  G11B23/087 ,  G11B23/107

摘要： Provided is a magnetic recording medium capable of curbing deterioration in electromagnetic conversion characteristics.
A magnetic recording medium with a tape shape includes a substrate that contains polyesters, an underlayer that is provided on the substrate, and a magnetic layer that is provided on the underlayer and contains a magnetic powder. The magnetic recording medium contains a lubricant. An average value of arithmetic average roughnesses Ra of a surface of the magnetic layer is 1.3 nm or less. In a case where an average value of peak half widths of a spacing increase region generated on an entrance side of a glass pseudo head which the magnetic recording medium enters when the magnetic recording medium is slid over the glass pseudo head is set as a spacing index SRL and an average value of peak half widths of a spacing increase region generated in the vicinity of an edge of the magnetic recording medium in a width direction when the magnetic recording medium is slid over the glass pseudo head is set as a spacing index SRT, the spacing index SRL is 35 μm or less and the spacing index SRT is 68 μm or less.