Patents by Inventor Minoru Yamaga

Minoru Yamaga has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11741991
    Abstract: A tape-shaped magnetic recording medium is provided with a base, an underlayer provided on the base, and a magnetic layer provided on the underlayer including magnetic powder including hexagonal ferrite. The underlayer and the magnetic layer include lubricant. The magnetic layer includes a surface provided with a large number of holes, and arithmetic average roughness Ra of the surface is 2.5 nm or smaller. A BET specific surface area of a whole of the magnetic recording medium in a state in which the lubricant is removed is 3.5 m2/mg or larger. A square ratio in a vertical direction is 65% or larger, an average thickness of the magnetic layer is 90 nm or smaller, and an average thickness of the magnetic recording medium is 5.6 ?m or smaller.
    Type: Grant
    Filed: November 19, 2018
    Date of Patent: August 29, 2023
    Assignee: Sony Corporation
    Inventors: Minoru Yamaga, Takanobu Iwama, Jun Takahashi
  • Patent number: 11688425
    Abstract: It is an object to provide a magnetic recording medium that enables good reproduction even after long-term preservation and that has a small overall thickness. The present technology provides a tape-shaped magnetic recording medium including a magnetic layer, a ground layer, a base layer, and a back layer, in which an average thickness tT of the magnetic recording medium is equal to or less than 5.3 ?m, and, when the magnetic recording medium is subjected to dynamic viscoelasticity measurement at a frequency of 10 Hz and a temperature rise rate of 2° C./min, a difference between a maximum and a minimum of a viscosity term E? in a temperature range of 0° C. to 80° C. is equal to or less than 0.18 GPa. In addition, the present technology also provides a tape cartridge including the tape-shaped magnetic recording medium.
    Type: Grant
    Filed: June 17, 2020
    Date of Patent: June 27, 2023
    Assignee: Sony Group Corporation
    Inventors: Minoru Yamaga, Tooru Sato, Kanako Hashimoto
  • Patent number: 11676631
    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 ?m or less, and a servo pattern is recorded on the magnetic layer and a statistical value ?SW indicating a non-linearity of the servo pattern is 24 nm or less.
    Type: Grant
    Filed: October 2, 2019
    Date of Patent: June 13, 2023
    Assignee: Sony Group Corporation
    Inventors: Noboru Sekiguchi, Minoru Yamaga
  • Patent number: 11651781
    Abstract: A magnetic recording medium according to the present technology is a tape-shaped magnetic recording medium including: a base material; and a magnetic layer, the tape-shaped magnetic recording medium being long in a longitudinal direction and short in a width direction, in which the magnetic layer includes a data band long in the longitudinal direction and a servo band long in the longitudinal direction, a data signal being written to the data band, a servo signal being written to the servo band, the degree of perpendicular orientation of the magnetic layer being 65% or more, a full width at half maximum of an isolated waveform in a reproduced waveform of the data signal is 185 nm or less, a thickness of the magnetic layer is 90 nm or less, and a thickness of the base material is 4.2 ?m or less.
    Type: Grant
    Filed: May 9, 2019
    Date of Patent: May 16, 2023
    Assignee: Sony Group Corporation
    Inventor: Minoru Yamaga
  • Publication number: 20230120213
    Abstract: A magnetic recording medium that can exhibit good traveling performance during use is provided. This magnetic recording medium is a tape-shaped magnetic recording medium, and includes a substrate, a base layer disposed on the substrate, and a magnetic layer disposed on the base layer. The substrate includes a polyester as a main component. The average thickness of the base layer is 0.9 ?m or less. The base layer and the magnetic layer each include a lubricant. The magnetic layer has a surface having a large number of holes, and the arithmetic average roughness Ra of the surface is 2.5 nm or less. The BET specific surface area of the entire magnetic recording medium is 3.5 m2/g or more in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried. The squareness ratio in the perpendicular direction is 65% or more. The average thickness of the magnetic layer is 90 nm or less. The average thickness of the magnetic recording medium is 5.
    Type: Application
    Filed: December 20, 2022
    Publication date: April 20, 2023
    Inventors: Kazuya HASHIMOTO, Minoru YAMAGA, Takanobu IWAMA, Jun TAKAHASHI
  • Publication number: 20230119551
    Abstract: An object is to further improve a thermal stability and an electromagnetic conversion characteristic of a magnetic recording medium. The present technology provides a magnetic recording medium that includes a layer structure including: a base layer; and a magnetic layer provided on the base layer and including a magnetic powder, in which an average particle volume of the magnetic powder is 2300 nm3 or less, and a magnetic interaction ?M calculated by the following expression (1) of the magnetic layer is ?0.362??M??0.22, ?M={Id(H)+2Ir(H)?Ir(?)}/Ir(?) ??(1) [where, in the expression (1), Id(H) is a remanent magnetization measured by a direct-current demagnetization, Ir(H) is a remanent magnetization measured by an alternating-current demagnetization, and Ir(?) is a remanent magnetization measured by an applied magnetic field of 6 kOe].
    Type: Application
    Filed: July 20, 2020
    Publication date: April 20, 2023
    Inventors: Taikei ENOMOTO, Masaru Jasper TERAKAWA, Minoru YAMAGA
  • Patent number: 11631430
    Abstract: A magnetic recording medium is provided and includes a magnetic layer, a non-magnetic layer, a base layer and a back layer, wherein an average thickness tT of the magnetic recording medium is tT?5.3 a dimensional change amount ?w in a width direction with respect to a change in tension in a longitudinal direction is 700 ppm/N??w, a thickness of the non-magnetic layer is 2.0 ?m or less, a squareness ratio measured in a vertical direction of the magnetic recording medium is 65% or more, and the magnetic layer includes a magnetic powder.
    Type: Grant
    Filed: April 6, 2021
    Date of Patent: April 18, 2023
    Assignee: Sony Group Corporation
    Inventors: Minoru Yamaga, Noboru Sekiguchi, Tooru Sato, Takashi Aizawa
  • Patent number: 11626128
    Abstract: An object of the present disclosure is to provide a magnetic recording medium excellent in electro-magnetic conversion characteristic and thermal stability. The present disclosure provides a tape-shaped magnetic recording medium including: a substrate; and a magnetic layer provided over the substrate and including a magnetic powder, in which the magnetic layer has an average thickness of equal to or less than 90 nm, the magnetic powder has an average aspect ratio of from 1.0 to 3.0, the magnetic powder has an average particle volume of equal to or less than 2,300 nm3, a coercive force Hc1 in a vertical direction of the magnetic recording medium is equal to or less than 4,500 Oe, a coercive force Hc2 in a longitudinal direction of the magnetic recording medium and the coercive force Hc1 satisfy a relation of Hc2/Hc1?0.8, and the ratio Hrp/Hc1 of a residual coercive force Hrp of the magnetic recording medium measured using a pulsed magnetic field and the coercive force Hc1 is equal to or less than 2.0.
    Type: Grant
    Filed: October 31, 2019
    Date of Patent: April 11, 2023
    Assignee: Sony Group Corporation
    Inventors: Masaru Terakawa, Minoru Yamaga
  • Patent number: 11615812
    Abstract: An object is to provide a magnetic recording medium having excellent traveling stability and a thin total thickness. The present technology provides a tape-shaped magnetic recording medium including: a magnetic layer; an underlayer; a base layer; and a back layer, in which a surface on a side of the magnetic layer has a kurtosis of 3.0 or more, a surface on a side of the back layer has a kurtosis of 2.0 or more, the surface on the magnetic layer side has arithmetic average roughness Ra of 2.5 nm or less, the base layer includes a polyester as a main component, the magnetic recording medium has an average thickness tT of 5.6 ?m or less, the magnetic recording medium includes a lubricant, the lubricant includes a fatty acid and a fatty acid ester, and a mass ratio between the fatty acid and the fatty acid ester extracted with hexane satisfies fatty acid/fatty acid ester?0.
    Type: Grant
    Filed: October 3, 2019
    Date of Patent: March 28, 2023
    Assignee: Sony Group Corporation
    Inventors: Minoru Yamaga, Takanobu Iwama, Jun Takahashi
  • Patent number: 11610604
    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 ?m, 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 ?m2 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 ?m×9.3 ?m on the surface of the magnetic layer in a vacuum is equal to or greater than 3.
    Type: Grant
    Filed: October 2, 2019
    Date of Patent: March 21, 2023
    Assignee: Sony Group Corporation
    Inventors: Minoru Yamaga, Futoshi Sasaki
  • Publication number: 20230075546
    Abstract: Provided is a magnetic recording medium that is able to achieve both an improvement in electromagnetic conversion characteristics and ensuring of high long-term reliability. The magnetic recording medium includes a magnetic layer and a base. The magnetic layer includes magnetic powders including ?-iron oxide. A ratio (Hrp/Hc) of residual coercivity (Hrp) measured in a perpendicular direction of the magnetic recording medium with use of a pulse magnetic field to perpendicular coercivity (Hc) of the magnetic recording medium is 2.0 or less. Saturation magnetization (Mst) per unit area of the magnetic recording medium is 4.5 mA or greater.
    Type: Application
    Filed: January 20, 2021
    Publication date: March 9, 2023
    Inventors: Takeshi TAKAHASHI, Katsunori MAESHIMA, Minoru YAMAGA, Masaru TERAKAWA, Natsuki ICHISE, Tomoe SATO, Takashi KATAGUCHI, Atsuya TOWATA, Kimihiro OZAKI, Akihiro MATSUMOTO
  • Patent number: 11581014
    Abstract: 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 ?m 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.
    Type: Grant
    Filed: October 8, 2020
    Date of Patent: February 14, 2023
    Assignee: Sony Corporation
    Inventors: Minoru Yamaga, Tooru Sato, Kanako Hashimoto
  • Publication number: 20230042175
    Abstract: A magnetic recording medium is a magnetic recording medium having a tape shape and includes a substrate, an underlayer provided on the substrate, and a magnetic layer provided on the underlayer. The magnetic layer has a surface having an uneven shape, a height range ?H obtained from statistical information of a height of the uneven shape is in a range of 4.00 nm ? ?H ? 10.00 nm, and a gradient range ?A obtained from statistical information of a gradient of the uneven shape is in a range of 2.50 degrees ? ?A.
    Type: Application
    Filed: January 19, 2021
    Publication date: February 9, 2023
    Inventors: Noboru SEKIGUCHI, Yuuko KAMOSHITA, Minoru YAMAGA
  • Patent number: 11574651
    Abstract: A magnetic recording medium, which is used in a recording and playback device in which the shortest recording wavelength is 75 nm or less, in which the magnetic recording medium has a recording layer including powder of ?-iron oxide-containing particles, the average particle size of the particles is 22 nm or less, the coercive force He is 220 kA/m or more and 320 kA/m or less, and the non linear transition shift is 20% or less.
    Type: Grant
    Filed: December 28, 2017
    Date of Patent: February 7, 2023
    Assignee: Sony Corporation
    Inventors: Masaru Terakawa, Yoichi Kanemaki, Minoru Yamaga
  • Patent number: 11538495
    Abstract: A magnetic recording medium that can exhibit good traveling performance during use is provided. This magnetic recording medium is a tape-shaped magnetic recording medium, and includes a substrate, a base layer disposed on the substrate, and a magnetic layer disposed on the base layer. The substrate includes a polyester as a main component. The average thickness of the base layer is 0.9 ?m or less. The base layer and the magnetic layer each include a lubricant. The magnetic layer has a surface having a large number of holes, and the arithmetic average roughness Ra of the surface is 2.5 nm or less. The BET specific surface area of the entire magnetic recording medium is 3.5 m2/g or more in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried. The squareness ratio in the perpendicular direction is 65% or more. The average thickness of the magnetic layer is 90 nm or less. The average thickness of the magnetic recording medium is 5.
    Type: Grant
    Filed: October 1, 2019
    Date of Patent: December 27, 2022
    Assignee: Sony Group Corporation
    Inventors: Kazuya Hashimoto, Minoru Yamaga, Takanobu Iwama, Jun Takahashi
  • Publication number: 20220399039
    Abstract: Provided is a magnetic recording medium configured to achieve higher density recording. The magnetic recording medium has a tape-like shape, and includes: a base containing polyester as a main constituent; and a magnetic layer provided on the base, including a plurality of magnetic powders, and configured to record a data signal. An average thickness of the magnetic recording medium is 5.6 ?m or less. An average thickness of the base is 4.2 ?m or less. An average thickness of the magnetic layer is 90 nm or less. An average aspect ratio of the magnetic powders is 1.0 or greater and 3.0 or less. A coercivity in a perpendicular direction is 3000 oersted or less. A rate of a coercivity in a longitudinal direction to the coercivity in the perpendicular direction is 0.8 or less. The magnetic layer includes a lubricant. An entire BET specific surface area of the magnetic recording medium from which the lubricant has been removed is 2.5 m2/g or greater.
    Type: Application
    Filed: October 31, 2019
    Publication date: December 15, 2022
    Inventors: Masaru TERAKAWA, Minoru YAMAGA
  • Patent number: 11527260
    Abstract: A magnetic recording medium that can exhibit good traveling performance during use is provided. This magnetic recording medium is a tape-shaped magnetic recording medium, and includes a substrate including a polyester as a main component, a base layer disposed on the substrate, a magnetic layer disposed on the base layer, and a back layer disposed on a side of the substrate opposite to the base layer. A surface of the back layer opposite to the substrate has a kurtosis of 2.0 or more. On a surface of the magnetic layer, recesses having a depth of 20% or more of the average thickness of the magnetic layer are formed at a ratio of 10 or more and 200 or less per 1600 ?m2. A surface of the magnetic layer has arithmetic average roughness Ra of 2.5 nm or less. The entire magnetic recording medium has a BET specific surface area of 3.5 m2/g or more in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried.
    Type: Grant
    Filed: October 1, 2019
    Date of Patent: December 13, 2022
    Assignee: Sony Group Corporation
    Inventors: Minoru Yamaga, Takanobu Iwama, Jun Takahashi
  • Publication number: 20220392488
    Abstract: A magnetic recording medium is a tape-shaped magnetic recording medium that has a recording layer including an ?-iron oxide particle. An area ratio Rlow (=(Slow/Stotal)×100) of a total area Stotal of an SFD curve of the recording layer in a perpendicular direction and an area Slow of the SFD curve in which a coercivity Hc is in a range from ?500 [Oe]?Hc?500 [Oe] is equal to or less than 5.5%.
    Type: Application
    Filed: September 4, 2020
    Publication date: December 8, 2022
    Inventors: Natsuki ICHISE, Minoru YAMAGA, Katsunori MAESHIMA, Masaru TERAKAWA, Takeshi TAKAHASHI, Tomoe SATO, Takashi KATAGUCHI
  • Patent number: 11521650
    Abstract: A magnetic recording medium includes a layer structure including a magnetic layer, a base layer, and a back layer in this order, in which an average thickness tT is tT?5.5 ?m, a dimensional variation ?w in a width direction to tension change in a longitudinal direction is 660 ppm/N??w, and a surface roughness Rabe of the base layer on a side of the back layer is 4.2 nm?Rabe?8.5 nm.
    Type: Grant
    Filed: May 24, 2021
    Date of Patent: December 6, 2022
    Assignee: Sony Corporation
    Inventors: Minoru Yamaga, Noboru Sekiguchi
  • Patent number: 11514941
    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.
    Type: Grant
    Filed: September 5, 2019
    Date of Patent: November 29, 2022
    Assignee: SONY CORPORATION
    Inventors: Masaru Terakawa, Minoru Yamaga