Patents by Inventor Kenichi Kuramoto
Kenichi Kuramoto 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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Patent number: 8873191Abstract: An embedded contact sensor (ECS) element for fly-height control and touchdown detection. An embedded contact sensor (ECS) element with a resistance that changes with a temperature change, which senses a clearance change between a head slider and a disk of a disk drive. A resistance measurement section, within said head IC, that determines a value of direct current resistance (DCR) of said ECS element, wherein said value of DCR changes with a temperature change, wherein said temperature change is caused by an air bearing cooling and frictional induced heating at a head disk interface. A resistance slope to fly-height conversion section that dynamically determines a target fly-height value for said head slider over said disk based on changes in said value of DCR.Type: GrantFiled: March 14, 2013Date of Patent: October 28, 2014Assignee: HGST Netherlands B.V.Inventors: Jianhua Li, Kenichi Kuramoto, Toshiya Shiramatsu, Yuichi Aoki, Masaru Furukawa, Yuichiro Sano
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Publication number: 20140268386Abstract: An embedded contact sensor (ECS) element for fly-height control and touchdown detection. An embedded contact sensor (ECS) element with a resistance that changes with a temperature change, which senses a clearance change between a head slider and a disk of a disk drive. A resistance measurement section, within said head IC, that determines a value of direct current resistance (DCR) of said ECS element, wherein said value of DCR changes with a temperature change, wherein said temperature change is caused by an air bearing cooling and frictional induced heating at a head disk interface. A resistance slope to fly-height conversion section that dynamically determines a target fly-height value for said head slider over said disk based on changes in said value of DCR.Type: ApplicationFiled: March 14, 2013Publication date: September 18, 2014Applicant: HGST Netherlands B.V.Inventors: Jianhua Li, Kenichi Kuramoto, Toshiya Shiramatsu, Yuichi Aoki, Masaru Furukawa, Yuichiro Sano
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Patent number: 8824091Abstract: Approaches for a flying height control scheme in a hard-disk drive (HDD) device. The flying height control scheme utilizes an embedded contact sensor (ECS) to characterize the topography of a magnetic-recording disk at various flying heights of a head slider over a corresponding disk. A relation between a particular flying height and a corresponding ECS value which characterizes the media topography at that particular flying height is represented in disk topography data. The disk topography data is accessed and used for active flying height control for the head-disk interface in view of the current ECS value.Type: GrantFiled: December 20, 2012Date of Patent: September 2, 2014Assignee: HGST Netherlands B.V.Inventors: John Contreras, Saurabh Deoras, Samir Garzon, Kenichi Kuramoto, Remmelt Pit
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Publication number: 20140177090Abstract: Approaches for a flying height control scheme in a hard-disk drive (HDD) device. The flying height control scheme utilizes an embedded contact sensor (ECS) to characterize the topography of a magnetic-recording disk at various flying heights of a head slider over a corresponding disk. A relation between a particular flying height and a corresponding ECS value which characterizes the media topography at that particular flying height is represented in disk topography data. The disk topography data is accessed and used for active flying height control for the head-disk interface in view of the current ECS value.Type: ApplicationFiled: December 20, 2012Publication date: June 26, 2014Applicant: HGST NETHERLANDS B.V.Inventors: JOHN CONTRERAS, SAURABH DEORAS, SAMIR GARZON, KENICHI KURAMOTO, REMMELT PIT
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Patent number: 8300337Abstract: A method for measuring change of clearance between a head and a disk. The method includes reading a preliminarily written data string for clearance measurement on a disk to obtain a first measured value corresponding to a clearance, and writing a new data string for deterioration check onto the disk and reading the data string for deterioration check to obtain a second measured value corresponding to the clearance. The method also includes determining a deterioration of the data string for clearance measurement from a difference between the first measured value and the second measured value, measuring a clearance change using the data string for clearance measurement by a normal operation if the determination is that the data string for clearance measurement has not deteriorated, and measuring a clearance change by an operation different from the normal operation if the determination is that the data string for clearance measurement has deteriorated.Type: GrantFiled: September 11, 2009Date of Patent: October 30, 2012Assignee: Hitachi Global Storage Technologies, Netherlands B.V.Inventors: Masayuki Kurita, Kenji Kuroki, Kenichi Kuramoto, Yoshihiko Maeda
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Patent number: 8254051Abstract: A disk drive. The disk drive includes a disk, a head, a head-slider, a moving mechanism, and a controller. The head is configured to access the disk. The head-slider includes the head, and is configured to fly in proximity to a recording surface of the disk. The moving mechanism is configured to move the head-slider over the disk, and to support the head-slider. The controller is configured to read out at least one from a plurality of clearance-measurement data strings from the recording surface of the disk using the head, and to calculate a clearance between the head and the disk from clearance-measurement results obtained from a plurality of resolutions with different frequency components.Type: GrantFiled: July 8, 2010Date of Patent: August 28, 2012Assignee: Hitachi Global Storage Technologies, Netherlands B.V.Inventor: Kenichi Kuramoto
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Patent number: 8009380Abstract: A disk drive. The disk drive includes a disk configured to store data, a slider configured to fly in proximity to the disk, and a magnetic-recording head on the slider configured to access the disk. The disk drive also includes a moving mechanism configured to support and to move the head-slider, an adjustment portion configured to adjust clearance between the magnetic-recording head and the disk, and a controller configured to control the adjustment portion to control the clearance. The controller is configured to perform clearance control in a first mode in an operation selected from the group consisting of reading user data and writing user data according to a change in fly height of the slider after a load operation, and subsequently is configured to perform clearance control in a second mode in an operation selected from the group consisting of reading user data and writing user data.Type: GrantFiled: November 20, 2009Date of Patent: August 30, 2011Assignee: Hitachi Global Storage Technologies, Netherlands, B.V.Inventors: Shinji Matsushita, Kenichi Kuramoto, Kenji Kuroki, Takahiro Nishioka, Masayuki Ishikawa
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Publication number: 20110102933Abstract: A method for measuring a change of a clearance between a head and a disk. The method includes reading a preliminarily written data string for clearance measurement on a disk to obtain a first measured value corresponding to a clearance, and writing a new data string for deterioration check onto the disk and reading the data string for deterioration check to obtain a second measured value corresponding to the clearance. The method also includes determining a deterioration of the data string for clearance measurement from a difference between the first measured value and the second measured value, measuring a clearance change using the data string for clearance measurement by a normal operation if the determination is that the data string for clearance measurement has not deteriorated, and measuring a clearance change by an operation different operation if the determination is that the data string for clearance measurement has deteriorated.Type: ApplicationFiled: September 11, 2009Publication date: May 5, 2011Inventors: Masayuki Kurita, Kenji Kuroki, Kenichi Kuramoto, Yoshihiko Maeda
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Patent number: 7894149Abstract: Embodiments of the present invention precisely measure clearance variation by temperature change using a value in a RW channel. In an embodiment of the present invention, an HDD measures resolution by signals in a RW channel. The measured resolution shows variations depending on temperature according to two factors. One factor is the clearance variation depending on the temperature and the other is the variation in operational property of the RW channel depending on the temperature. The HDD compensates for the temperature variation of the resolution according to the two factors. The HDD uses two kinds of sensed temperature. One corresponds to the temperature inside an enclosure in which head sliders are provided and the other corresponds to the temperature of the chip in which the RW channel is implemented. Sensing the drive temperature and the channel temperature independently achieves precise compensation for the variation in the measured resolution caused by clearance variation and channel property.Type: GrantFiled: January 27, 2009Date of Patent: February 22, 2011Assignee: Hitachi Global Storage Technologies, Netherlands, B.V.Inventors: Hiroyasu Masuda, Yoshihiko Maeda, Kenichi Kuramoto, Masayuki Kurita, Kenji Kuroki
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Publication number: 20110007416Abstract: A disk drive. The disk drive includes a disk, a head, a head-slider, a moving mechanism, and a controller. The head is configured to access the disk. The head-slider includes the head, and is configured to fly in proximity to a recording surface of the disk. The moving mechanism is configured to move the head-slider over the disk, and to support the head-slider. The controller is configured to read out at least one from a plurality of clearance-measurement data strings from the recording surface of the disk using the head, and to calculate a clearance between the head and the disk from clearance-measurement results obtained from a plurality of resolutions with different frequency components.Type: ApplicationFiled: July 8, 2010Publication date: January 13, 2011Inventor: Kenichi KURAMOTO
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Patent number: 7852594Abstract: Embodiments of the present invention help to detect contact between a head and a magnetic disk more accurately in specifying a heater power value for adjusting a clearance between a head element portion and the disk. According to one embodiment, a hard disk controller/multiprocessing unit (HDC/MPU) measures amplitudes of read signals in a user data field DATA. A hard disk drive (HDD) fills a gap between servo data with single data sector. The HDC/MPU measures the amplitudes of read signals in each data sector at different heater power values. It determines the heater power value at which contact occurs from the measured values.Type: GrantFiled: May 28, 2008Date of Patent: December 14, 2010Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Yoshihiko Maeda, Takao Matsui, Nobuhiro Kuwamura, Kenichi Kuramoto, Akihiro Sera
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Patent number: 7800855Abstract: Embodiments of the present invention help to prevent destabilization in voice coil motor (VCM) velocity control. According to one embodiment, a hard disk controller/multiprocessing unit (HDC/MPU) calibrates a correction operational coefficient of a detected back electromotive force (EMF) voltage before unloading. The calibration is carried out in a state that an actuator is pivoting. The HDC/MPU calibrates the correction coefficient according to a motion equation of the actuator using VCM current applied to a VCM and a detected value of a back EMF voltage detection circuit.Type: GrantFiled: November 14, 2007Date of Patent: September 21, 2010Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Kenichi Kuramoto, Shinya Sakamoto, Nobuhiko Wasa, Sayaka Nojiri, Hidefumi Tominaga
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Publication number: 20100128383Abstract: A disk drive. The disk drive includes a disk configured to store data, a slider configured to fly in proximity to the disk, and a magnetic-recording head on the slider configured to access the disk. The disk drive also includes a moving mechanism configured to support and to move the head-slider, an adjustment portion configured to adjust clearance between the magnetic-recording head and the disk, and a controller configured to control the adjustment portion to control the clearance. The controller is configured to perform clearance control in a first mode in an operation selected from the group consisting of reading user data and writing user data according to a change in fly height of the slider after a load operation, and subsequently is configured to perform clearance control in a second mode in an operation selected from the group consisting of reading user data and writing user data.Type: ApplicationFiled: November 20, 2009Publication date: May 27, 2010Inventors: Shinji MATSUSHITA, Kenichi Kuramoto, Kanji Kuroki, Takahiro Nishioka, Masayuki Ishikawa
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Patent number: 7706097Abstract: Embodiments of the invention improve utility of a magnetic disk drive in which a head is retracted if the magnetic disk drive is in a dropping state. In one embodiment, an HDC/MPU provided in a magnetic disk drive judges whether the magnetic disk drive is in a dropping state based on an output from an acceleration sensor which may detect an acceleration and performs a retraction operation of a head. After the HDC/MPU judges that a drop is occurring, the HDC/MPU detects whether the drop judgment is incorrect according to whether a shock sensor detects a shock occurrence and changes the drop judgment condition based on a detection history of detected incorrect judgments.Type: GrantFiled: September 19, 2008Date of Patent: April 27, 2010Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Kenji Kuroki, Toru Aida, Kenichi Kuramoto, Yasuhiro Kotani
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Publication number: 20090296260Abstract: Embodiments of the present invention help to detect contact between a head and a magnetic disk more accurately in specifying a heater power value for adjusting a clearance between a head element portion and the disk. According to one embodiment, a hard disk controller/multiprocessing unit (HDC/MPU) measures amplitudes of read signals in a user data field DATA. A hard disk drive (HDD) fills a gap between servo data with single data sector. The HDC/MPU measures the amplitudes of read signals in each data sector at different heater power values. It determines the heater power value at which contact occurs from the measured values.Type: ApplicationFiled: May 28, 2008Publication date: December 3, 2009Applicant: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Yoshihiko Maeda, Takao Matsui, Nobuhiro Kuwamura, Kenichi Kuramoto, Akihiro Sera
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Publication number: 20090201598Abstract: Embodiments of the present invention precisely measure clearance variation by temperature change using a value in a RW channel. In an embodiment of the present invention, an HDD measures resolution by signals in a RW channel. The measured resolution shows variations depending on temperature according to two factors. One factor is the clearance variation depending on the temperature and the other is the variation in operational property of the RW channel depending on the temperature. The HDD compensates for the temperature variation of the resolution according to the two factors. The HDD uses two kinds of sensed temperature. One corresponds to the temperature inside an enclosure in which head sliders are provided and the other corresponds to the temperature of the chip in which the RW channel is implemented. Sensing the drive temperature and the channel temperature independently achieves precise compensation for the variation in the measured resolution caused by clearance variation and channel property.Type: ApplicationFiled: January 27, 2009Publication date: August 13, 2009Inventors: Hiroyasu Masuda, Yoshihiko Maeda, Kenichi Kuramoto, Masayuki Kurita, Kenji Kuroki
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Publication number: 20090141391Abstract: Embodiments of the present invention help to precisely control the clearance between a head and disk for the pressure without using a barometric sensor. In an embodiment of the present invention, an HDD determines a clearance from variations in operational parameters, and further determines a variation in pressure by deducting the clearance variation caused by a variation in temperature from the clearance. When the HDD controls the clearance in accordance with the pressure change, the HDD checks for head-disk contact. The accuracy and reliability in pressure measurement (clearance measurement) using operational parameters are not high. Therefore, confirming the pressure measurement by the presence or absence of head-disk contact eliminates head-disk contact in the following read/write operation to attain a securer margin for the clearance.Type: ApplicationFiled: October 30, 2008Publication date: June 4, 2009Inventors: Kenichi Kuramoto, Masayuki Kurita, Yoshihiko Maeda, Hidetsugu Tanaka, Akihiro Sera, Katsumasa Yamazaki
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Publication number: 20090034114Abstract: Embodiments of the invention improve utility of a magnetic disk drive in which a head is retracted if the magnetic disk drive is in a dropping state. In one embodiment, an HDC/MPU provided in a magnetic disk drive judges whether the magnetic disk drive is in a dropping state based on an output from an acceleration sensor which may detect an acceleration and performs a retraction operation of a head. After the HDC/MPU judges that a drop is occurring, the HDC/MPU detects whether the drop judgment is incorrect according to whether a shock sensor detects a shock occurrence and changes the drop judgment condition based on a detection history of detected incorrect judgments.Type: ApplicationFiled: September 19, 2008Publication date: February 5, 2009Applicant: Hitachi Global Storage Technlogies Netherlands B.V.Inventors: Kenji Kuroki, Toru Aida, Kenichi Kuramoto, Yasuhiro Kotani
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Patent number: 7428119Abstract: Embodiments of the invention improve utility of a magnetic disk drive in which a head is retracted if the magnetic disk drive is in a dropping state. In one embodiment, an HDC/MPU provided in a magnetic disk drive judges whether the magnetic disk drive is in a dropping state based on an output from an acceleration sensor which may detect an acceleration and performs a retraction operation of a head. After the HDC/MPU judges that a drop is occurring, the HDC/MPU detects whether the drop judgment is incorrect according to whether a shock sensor detects a shock occurrence and changes the drop judgment condition based on a detection history of detected incorrect judgments.Type: GrantFiled: October 18, 2006Date of Patent: September 23, 2008Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Kenji Kuroki, Toru Aida, Kenichi Kuramoto, Yasuhiro Kotani
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Publication number: 20080123216Abstract: Embodiments of the present invention help to prevent destabilization in voice coil motor (VCM) velocity control. According to one embodiment, a hard disk controller/multiprocessing unit (HDC/MPU) calibrates a correction operational coefficient of a detected back electromotive force (EMF) voltage before unloading. The calibration is carried out in a state that an actuator is pivoting. The HDC/MPU calibrates the correction coefficient according to a motion equation of the actuator using VCM current applied to a VCM and a detected value of a back EMF voltage detection circuit.Type: ApplicationFiled: November 14, 2007Publication date: May 29, 2008Applicant: Hitachi Global Storage Technologies Inc.Inventors: Kenichi Kuramoto, Shinya Sakamoto, Nobuhiko Wasa, Sayaka Nojiri, Hidefumi Tominaga