Sony Group Assigned Five Patents

Magnetic recording medium
Sony Group Corporation, Tokyo, Japan, has been assigned a patent (11615812) developed by Yamaga, Minoru, Iwama, Takanobu, and Takahashi, Jun, Miyagi, Japan, for a “magnetic recording medium.”

The abstract of the patent published by the U.S. Patent and Trademark Office states: “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 R.sub.a of 2.5 nm or less, the base layer includes a polyester as a main component, the magnetic recording medium has an average thickness t.sub.T of 5.6 μm 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≤0.6, and the magnetic recording medium has pores, and the pores have an average diameter of 6 nm or more and 11 nm or less when the diameters of the pores are measured in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried.”

The patent application was filed on 2019-10-03 (16/649482).

Magnetic recording medium, cartridge, and recording and reproducing device
Sony Group Corporation, Tokyo, Japan, has been assigned a patent (11610604) developed by Yamaga, Minoru, and Sasaki, Futoshi, Miyagi, Japan, for “magnetic recording medium, cartridge, and recording and reproducing device.”

The abstract of the patent published by the U.S. Patent and Trademark Office states: “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 μm.sup.2 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 μm.sup.2 and equal to or smaller than 6.5 μm.sup.2.”

The patent application was filed on 2019-10-02 (16/649400).

Magnetic recording medium
Sony Group Corporation, Tokyo, Japan, has been assigned a patent (11581014) developed by Yamaga, Minoru, Sato, Tooru, and Hashimoto, Kanako, Tokyo, Japan, for a “magnetic recording medium.”

The abstract of the patent published by the U.S. Patent and Trademark Office states: “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 t.sub.T 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.”

The patent application was filed on 2020-10-08 (17/259072).

Magnetic recording medium having -iron oxide-containing particles
Sony Group Corporation, Tokyo, Japan, has been assigned a patent (11574651) developed by Terakawa, Masaru, Kanemaki, Yoichi, and Yamaga, Minoru, Miyagi, Japan, for a “magnetic recording medium having -iron oxide-containing particles.”

The abstract of the patent published by the U.S. Patent and Trademark Office states: “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 ε-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.”

The patent application was filed on 2017-12-28 (16/477687).

Magnetic recording medium, magnetic recording/reproducing device, and magnetic recording medium cartridge
Sony Group Corporation, Tokyo, Japan, has been assigned a patent (11538495) developed by Hashimoto, Kazuya, Yamaga, Minoru, Iwama, Takanobu, and Takahashi, Jun, Miyagi, Japan, for “magnetic recording medium, magnetic recording/reproducing device, and magnetic recording medium cartridge.”

The abstract of the patent published by the U.S. Patent and Trademark Office states: “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 μm 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 m.sup.2/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 5.6 μm or less.”

The patent application was filed on 2019-10-01 (16/651454).