Patents by Inventor Masayoshi Shimokoshi
Masayoshi Shimokoshi 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).
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Publication number: 20230005503Abstract: Various apparatuses, systems, methods, and media are disclosed to provide a heat-assisted magnetic recording (HAMR) medium that has a magnesium (Mg) trapping layer that is configured to mitigate Mg migration in the HAMR medium so as to prevent near field transducer (NFT) damage caused by dissociated Mg reacting with a compound used in the NFT. In one example, the HAMR medium can include a substrate, a seed layer on the substrate and including MgO, a magnetic recording layer on the seed layer, and a Mg trapping layer on the substrate and configured to mitigate Mg migration from the seed layer to a surface of the HAMR medium above the magnetic recording layer.Type: ApplicationFiled: July 1, 2021Publication date: January 5, 2023Inventors: Takashi Iwanami, Kouji Matsuda, Junguo Xu, Kenji Tasaka, Hoan Cong Ho, Tomoko Seki, Paul Christopher Dorsey, Masayoshi Shimokoshi
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Patent number: 8169730Abstract: A hard disk drive (HDD) comprising a magnetic disk that includes a data storage surface and an external magnetic field parallel to the data storage surface for suppressing track interference.Type: GrantFiled: December 17, 2009Date of Patent: May 1, 2012Assignee: Hitachi Global Storage Technologies, Netherlands, B.V.Inventors: Nelson Cheng, Lakshmi Ramamoorthy, Kris Schouterden, Masayoshi Shimokoshi
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Patent number: 8068306Abstract: Approaches for improving the write quality of a hard-disk drive (HDD) head experiencing temporary fly-height problem. When the hard-disk drive is idle and heads are parked on the ramp, fluid, such as a lubricant or the condensation of vapor, may collect between the surface of a platter and the head or a slider, thereby causing the head to temporarily fly higher than normal. An HDD may include electronic component(s) configured to (a) determine whether it is likely that fluid is interposed between the surface of a magnetic-recording disk and the slider or the head, and (b) temporarily adjust one or more of (i) a thermal fly height control setting of the head and (ii) a write parameter of the head to compensate for the head flying higher than normal as a result of the fluid being interposed between the surface of the disk and the slider or the head.Type: GrantFiled: December 14, 2009Date of Patent: November 29, 2011Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Lakshmi Ramamoorthy, David Jen, Douglas Zuercher, Masayoshi Shimokoshi, Kris Schouterden
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Publication number: 20110149427Abstract: A hard disk drive (HDD) comprising a magnetic disk that includes a data storage surface and an external magnetic field parallel to the data storage surface for suppressing track interference.Type: ApplicationFiled: December 17, 2009Publication date: June 23, 2011Inventors: Nelson Cheng, Lakshmi Ramamoorthy, Kris Schouterden, Masayoshi Shimokoshi
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Publication number: 20110141607Abstract: Approaches for improving the write quality of a hard-disk drive (HDD) head experiencing temporary fly-height problem. When the hard-disk drive is idle and heads are parked on the ramp, fluid, such as a lubricant or the condensation of vapor, may collect between the surface of a platter and the head or a slider, thereby causing the head to temporarily fly higher than normal. An HDD may include electronic component(s) configured to (a) determine whether it is likely that fluid is interposed between the surface of a magnetic-recording disk and the slider or the head, and (b) temporarily adjust one or more of (i) a thermal fly height control setting of the head and (ii) a write parameter of the head to compensate for the head flying higher than normal as a result of the fluid being interposed between the surface of the disk and the slider or the head.Type: ApplicationFiled: December 14, 2009Publication date: June 16, 2011Inventors: Lakshmi Ramamoorthy, David Jen, Douglas Zuercher, Masayoshi Shimokoshi, Kris Schouterden
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Patent number: 7369351Abstract: Embodiments of the invention reduce the error rate of a read error that is caused by a spacing interval between a write head and a read head, which are formed on a slider. In one embodiment, a write head writes user data, which is placed at a position, on a magnetic disk when a read head is placed at a target position in accordance with a head spacing interval and yaw angle. DHO adjustment data is written at a second position, which is obtained by subjecting the read head to DHO correction in order to read the user data written at the target position. When the user data is to be read, a processor reads the DHO adjustment data, changes the read head position to the first position, and controls the operation of a magnetic disk drive to read the user data.Type: GrantFiled: November 22, 2005Date of Patent: May 6, 2008Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Kazuyuki Date, Masayoshi Shimokoshi
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Patent number: 7110203Abstract: A magnetic disk drive improved in reliability of data retrieve. This invention prevents the drive from decoding already-written old data. The failure decoding is caused by a deviation in a write operation, by a malfunction of a writing head and so on. When data in a sector is renewed, the sector's location and renewal frequency information are saved not only in the sector of the disk media but also in a temporary memory. When the magnetic disk drive is in an idle mode, those renewal information written in the sector and stored in the temporary memory, are checked. If both renewal information match, the data is regarded “not old” and the information about the sector in the temporary memory is deleted. In the deleting operation, check mark information indicating that the written data has been checked is written in the sector of the magnetic disk medium.Type: GrantFiled: August 30, 2002Date of Patent: September 19, 2006Assignee: Hitachi Global Storage Technologies Japan Ltd.Inventor: Masayoshi Shimokoshi
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Publication number: 20060139791Abstract: Embodiments of the invention reduce the error rate of a read error that is caused by a spacing interval between a write head and a read head, which are formed on a slider. In one embodiment, a write head writes user data, which is placed at a position, on a magnetic disk when a read head is placed at a target position in accordance with a head spacing interval and yaw angle. DHO adjustment data is written at a second position, which is obtained by subjecting the read head to DHO correction in order to read the user data written at the target position. When the user data is to be read, a processor reads the DHO adjustment data, changes the read head position to the first position, and controls the operation of a magnetic disk drive to read the user data.Type: ApplicationFiled: November 22, 2005Publication date: June 29, 2006Applicant: Hitachi Global Storage Technogoies Netherlands B.V.Inventors: Kazuyuki Date, Masayoshi Shimokoshi
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Patent number: 7023641Abstract: In a magnetic disk drive, a writing element and its surrounding area thermally expand due to the heat generated by a write head coil. The transient phenomenon of such thermal expansion may invoke the transient phenomenon of inadequate writing capacity, thereby causing a writing error at an early stage of a write operation. Control is provided which increases/decreases either or both the write current to be applied to a write head and the amount of its overshoot on an individual sector basis during a writing sequence.Type: GrantFiled: September 26, 2003Date of Patent: April 4, 2006Assignee: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Takeshi Doi, Masayoshi Shimokoshi, Hitoshi Yoshida
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Publication number: 20040184177Abstract: In a magnetic disk drive, a writing element and its surrounding area thermally expand due to the heat generated by a write head coil. The transient phenomenon of such thermal expansion may invoke the transient phenomenon of inadequate writing capacity, thereby causing a writing error at an early stage of a write operation. Control is provided which increases/decreases either or both the write current to be applied to a write head and the amount of its overshoot on an individual sector basis during a writing sequence.Type: ApplicationFiled: September 26, 2003Publication date: September 23, 2004Applicant: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Takeshi Doi, Masayoshi Shimokoshi, Hitoshi Yoshida
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Patent number: 6747833Abstract: The position information of the magnetic head is generated also from the data area to improve the positioning accuracy. The magnetic disk drive has a function of oscillating the magnetic head in the radial direction in the data area at a specific frequency and a function of detecting a read signal during the execution of the oscillation function and detects position information of the magnetic head from the detected read signal. The magnetic head position control can be performed in the data area. The magnetic head position signal not dependent on the frequency of a sampling signal generated from the servo information area can be generated. This in turn improves the data recording density and allows a highly precise position control of the magnetic head, thus improving the reliability of the magnetic disk drive.Type: GrantFiled: June 25, 2001Date of Patent: June 8, 2004Assignee: Hitachi, Ltd.Inventors: Masayoshi Shimokoshi, Takeshi Doi
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Publication number: 20030193729Abstract: A magnetic disk drive improved in reliability of data retrieve. This invention prevents the drive from decoding already-written old data. The failure decoding is caused by a deviation in a write operation, by a malfunction of a writing head and so on. When data in a sector is renewed, the sector's location and renewal frequency information are saved not only in the sector of the disk media but also in a temporary memory. When the magnetic disk drive is in an idle mode, those renewal information written in the sector and stored in the temporary memory, are checked. If both renewal information match, the data is regarded “not old” and the information about the sector in the temporary memory is deleted. In the deleting operation, check mark information indicating that the written data has been checked is written in the sector of the magnetic disk medium.Type: ApplicationFiled: August 30, 2002Publication date: October 16, 2003Inventor: Masayoshi Shimokoshi
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Publication number: 20020089778Abstract: The position information of the magnetic head is generated also from the data area to improve the positioning accuracy. The magnetic disk drive has a function of oscillating the magnetic head in the radial direction in the data area at a specific frequency and a function of detecting a read signal during the execution of the oscillation function and detects position information of the magnetic head from the detected read signal. The magnetic head position control can be performed in the data area. The magnetic head position signal not dependent on the frequency of a sampling signal generated from the servo information area can be generated. This in turn improves the data recording density and allows a highly precise position control of the magnetic head, thus improving the reliability of the magnetic disk drive.Type: ApplicationFiled: June 25, 2001Publication date: July 11, 2002Inventors: Masayoshi Shimokoshi, Takeshi Doi