公开(公告)号：US20230274764A1

公开(公告)日：2023-08-31

申请号：US18123510

申请日：2023-03-20

Applicant: Sony Corporation

Inventor： Minoru YAMAGA ,  Futoshi SASAKI

IPC: G11B5/706 ,  G11B5/73 ,  G11B5/735 ,  G11B5/592 ,  G11B5/71 ,  G11B5/714

CPC classification number: G11B5/70678 ,  G11B5/73927 ,  G11B5/7358 ,  G11B5/5928 ,  G11B5/71 ,  G11B5/714

Abstract: A magnetic recording medium is a magnetic recording medium in the form of a tape and includes a substrate, a foundation layer provided on the substrate, and a magnetic layer provided on the foundation layer and containing a magnetic powder. The foundation layer and the magnetic layer each contain a lubricant. A squareness ratio of the magnetic layer in a perpendicular direction is equal to or higher than 65%, an average thickness of the magnetic recording medium is equal to or smaller than 5.6 μm, a plurality of recessed portions each having a depth corresponding to 20% or higher of the average thickness of the magnetic layer is provided on a surface of the magnetic layer, and the number of the recessed portions per unit area of 1,600 μm2 of the surface of the magnetic layer is equal to or greater than 20 and equal to or smaller than 200, and an amount of exudation of the lubricant per unit region of 12.5 μm×9.3 μm on the surface of the magnetic layer in a vacuum is equal to or greater than 3.0 μm2 and equal to or smaller than 6.5 μm2.

公开(公告)号：US20220270643A1

公开(公告)日：2022-08-25

申请号：US17259072

申请日：2020-10-08

Applicant: Sony Corporation

Inventor： Minoru YAMAGA ,  Tooru SATO ,  Kanako HASHIMOTO

IPC: G11B5/706 ,  G11B5/78 ,  G11B5/008

Abstract: It is an object of the present technology to provide a magnetic recording medium having a small total thickness, which can be reproduced satisfactorily after long-term storage.
The present technology provides a tape-shaped magnetic recording medium including a magnetic layer, an underlayer, a base layer, and a back layer. The magnetic recording medium has an average thickness tT of 5.4 μm or less, when a thermomechanical analysis is performed on the magnetic recording medium in a temperature range of 40° C. to 150° C. at a temperature rise rate of 1° C./minute, a switching temperature for switching from thermal expansion to thermal contraction is 70° C. or more, and a contraction start temperature is 90° C. or more at which a length in a longitudinal direction is shorter than the length at 40° C., and a Poisson's ratio is 0.40 or less.

公开(公告)号：US20210350827A1

公开(公告)日：2021-11-11

申请号：US17272159

申请日：2019-09-05

Applicant: Sony Corporation

Inventor： Masaru TERAKAWA ,  Minoru YAMAGA

IPC: G11B5/706

Abstract: A magnetic recording medium used on a record/playback device with a minimum recording wavelength or 50 nm or shorter, the magnetic recording medium including a magnetic layer that contains a spinel-type ferrite magnetic powder, the magnetic layer having an average thickness of 85 nm or smaller, and the magnetic layer having a saturation flux density of 1600 Gauss or larger and 2000 Gauss or smaller.

公开(公告)号：US20210151075A1

公开(公告)日：2021-05-20

申请号：US17156136

申请日：2021-01-22

Applicant: Sony Corporation

Inventor： Minoru YAMAGA ,  Noboru SEKIGUCHI

IPC: G11B5/66 ,  G11B23/03 ,  G11B5/706 ,  G11B5/133 ,  G11B5/596

Abstract: A magnetic recording medium is provided and includes a substrate; and a magnetic layer provided over the substrate, wherein (wmax−wmin)/wmin≤400 [ppm] . . . (1) where wmax and wmin are respectively maximum and minimum of average values of width corresponding to samples of magnetic recording medium measured after the samples are stored for two hours under storage conditions (a loading tension in the longitudinal direction of the magnetic recording medium, a temperature and a relative humidity) for each of the samples, and a width of a sample of the magnetic recording medium at 25° C. and 50% relative humidity and without loading is ½ inch, magnetic recording medium has Young's modulus of less than 8.0 GPa in a longitudinal direction, and 4.0≤TB/(TA−TB) . . . (2) where TA is average thickness of magnetic recording medium and TB is average thickness of substrate.

公开(公告)号：US20200372932A1

公开(公告)日：2020-11-26

申请号：US16992908

申请日：2020-08-13

Applicant: Sony Corporation

Inventor： Masaru TERAKAWA ,  Minoru YAMAGA ,  Katsunori MAESHIMA

IPC: G11B5/78 ,  G11B5/584 ,  G11B5/008

Abstract: A tape-shaped magnetic recording medium includes a substrate; and a magnetic layer that is provided on the substrate and contains a magnetic powder. An average thickness of the magnetic layer is not more than 90 nm, an average aspect ratio of the magnetic powder is not less than 1.0 and not more than 3.0, the coercive force Hc1 in a vertical direction is not more than 3000 Oe, the coercive force Hc1 in the vertical direction and a coercive force Hc2 in a longitudinal direction satisfy a relationship of Hc2/Hc1≤0.8, and a value of σ1.5−σ0.5 is not more than 0.6 N in a tensile test of the magnetic recording medium in the longitudinal direction, where σ0.5 is a load at an elongation rate of 0.5% in the magnetic recording medium and σ1.5 is a load at an elongation rate of 1.5% in the magnetic recording medium.

公开(公告)号：US20190143637A1

公开(公告)日：2019-05-16

申请号：US16099625

申请日：2017-05-11

Applicant: Sony Corporation

Inventor： Eiji NAKASHIO ,  Yuta AKIMOTO ,  Tomoe SATO ,  Yoichi KANEMAKI ,  Nobuyuki SASAKI ,  Masaru TERAKAWA ,  Kazuya HASHIMOTO ,  Katsunori MAESHIMA ,  Minoru YAMAGA ,  Hikaru TERUI ,  Hiroyuki KOBAYASHI

IPC: B32B7/02 ,  G11B5/735 ,  G11B5/738 ,  G11B5/78

Abstract: A magnetic recording medium according to a first technique includes an elongated substrate having a first surface and a second surface, a first reinforcing layer disposed on the first surface, a second reinforcing layer disposed on the second surface, an adhesion suppressing layer disposed on the second reinforcing layer, and a recording layer disposed on the first reinforcing layer or the adhesion suppressing layer.

公开(公告)号：US20220172742A1

公开(公告)日：2022-06-02

申请号：US16651542

申请日：2019-10-02

Applicant: Sony Corporation

Inventor： Noboru SEKIGUCHI ,  Minoru YAMAGA

IPC: G11B5/714 ,  G11B5/706 ,  G11B5/592 ,  G11B5/78

Abstract: A magnetic recording medium is a tape-shaped magnetic recording medium, including: a substrate; an underlayer provided on the substrate; and a magnetic layer provided on the underlayer. The substrate contains polyester, each of the underlayer and the magnetic layer contains a lubricant, the magnetic layer has a surface on which a large number of holes is provided, the arithmetic average roughness Ra of the surface is 2.5 nm or less, a BET specific surface area of the entire magnetic recording medium measured in a state where the magnetic recording medium has been washed and dried is 3.5 m2/g or more and 7.0 m2/g or less, a squareness ratio of the magnetic layer in a vertical direction is 65% or more, an average thickness of the magnetic layer is 80 nm or less, an average thickness of the magnetic recording medium is 5.6 μm or less, and a servo pattern is recorded on the magnetic layer and a statistical value δSW indicating a non-linearity of the servo pattern is 24 nm or less.

公开(公告)号：US20210125634A1

公开(公告)日：2021-04-29

申请号：US16605469

申请日：2018-11-19

Applicant: Sony Corporation

Inventor： Minoru YAMAGA ,  Takanobu IWAMA ,  Jun TAKAHASHI

IPC: G11B5/73 ,  G11B5/78

Abstract: This technology aims to provide a magnetic recording tape and the like, which allow the tape to stably run at high speed while maintaining a state in which the distance between a magnetic head and the tape is held narrow.
This technology provides a magnetic recording tape having a plural-layer structure including at least a magnetic layer. The tape has a total thickness of 5.6 μm or smaller, and includes a plurality of indentations disposed in a surface of the magnetic layer. A value obtained by dividing a depth D1 of each indentation with a thickness D2 of the magnetic layer is 15% or greater. The magnetic layer is perpendicularly oriented, and has a perpendicular orientation of 65% or greater under condition of no demagnetization correction. The magnetic layer includes a plurality of indentations formed therein, a plurality of the indentations each has a depth of 20% or greater of the thickness of the magnetic layer, and the number of the indentations is 55 or more per 6,400 μm2 of a surface area of the magnetic layer. This technology also provides a manufacturing method of the magnetic recording tape.

公开(公告)号：US20210020196A1

公开(公告)日：2021-01-21

申请号：US17032718

申请日：2020-09-25

Applicant: Sony Corporation

Inventor： Noboru SEKIGUCHI ,  Minoru YAMAGA

IPC: G11B5/62 ,  C23C14/00 ,  G11B5/735 ,  G11B5/733 ,  G11B5/706

Abstract: The average thickness tT of a magnetic recording medium meets the requirement that tT≤5.5 [μm], and the dimensional change amount Δw in the width direction of the magnetic recording medium with respect to the tension change in the longitudinal direction of the magnetic recording medium meets the requirement that 700 ppm/N≤Δw.

公开(公告)号：US20210012805A1

公开(公告)日：2021-01-14

申请号：US16969876

申请日：2019-02-18

Applicant: Sony Corporation

Inventor： Masaru TERAKAWA ,  Minoru YAMAGA ,  Takanobu IWAMA ,  Jun TAKAHASHI

IPC: G11B20/12 ,  G11B5/733 ,  G11B5/706 ,  G11B5/008

Abstract: [Object] Provided is a technology that is capable of further improving a recording density of data.
[Solving Means] A magnetic recording medium according to the present technology is a magnetic recording medium in a shape of a tape that is long in a longitudinal direction and is short in a width direction, the medium including: a base material; a magnetic layer; and a non-magnetic layer that is provided between the base material and the magnetic layer, and contains one or more types of non-magnetic inorganic particles, in which the magnetic layer includes a data band long in the longitudinal direction in which a data signal is to be written, and a servo band long in the longitudinal direction in which a servo signal is written, and in the magnetic layer, a degree of vertical orientation is greater than or equal to 65%, a half width of a solitary waveform in a reproduction waveform of the servo signal is less than or equal to 195 nm, and a thickness of the magnetic layer is less than or equal to 90 nm, and the non-magnetic layer contains at least Fe-based non-magnetic particles as the non-magnetic inorganic particles, and in the non-magnetic layer, an average particle volume of the Fe-based non-magnetic particles is less than or equal to 2.0×10−5 μm3, and a thickness of the non-magnetic layer is less than or equal to 1.1 μm.