Controlling The Head Patents (Class 360/75)
Azimuth or skew (Class 360/76)
Track centering (Class 360/77.01)
Track changing (Class 360/78.01)
  • Skew compensation in a patterned medium
    Patent number: 9275676
    Abstract: Apparatus for providing skew compensation in a patterned medium, such as but not limited to a self-assembling bit patterned medium. In accordance with some embodiments, the apparatus includes a transducer and a rotatable substrate. The substrate has a plurality of rows of spaced apart data recording dots. Each row of dots is angularly offset from an immediately adjacent row responsive to a skew angle of the transducer. The rows of dots are arranged into concentric zones of hypertracks. Each zone has an arcuate timing field segment which extends across the zone and is angularly discontinuous with the timing field segment of an immediately adjacent zone.
    Type: Grant
    Filed: February 28, 2014
    Date of Patent: March 1, 2016
    Assignee: Seagate Technology LLC
    Inventors: Bruce Buch, Phillip L. Steiner
  • Magnetic tape storage medium
    Patent number: 9263073
    Abstract: A magnetic tape storage medium includes at least one servo band with at least two sub-bands along a longitudinal extension of the medium. Servo bursts are written to the sub-bands to determine positional information of the medium. A first of the sub-bands includes a first burst with at least one servo stripe inclined at a first non-zero angle with respect to a direction orthogonal to the longitudinal extension of the medium followed by a second burst comprising at least one servo stripe inclined at a second non-zero angle with respect to the direction orthogonal to the longitudinal extension of the medium, which second angle is different from the first angle. A second of the sub-bands includes a first burst having at least one servo stripe followed by a second burst having at least one servo stripe, the first and the second bursts parallel to each other.
    Type: Grant
    Filed: June 22, 2015
    Date of Patent: February 16, 2016
    Assignee: International Business Machines Corporation
    Inventors: Giovanni Cherubini, Simeon Furrer, Jens Jelitto, Mark A. Lantz
  • Magnetization control for magnetic shield in magnetic recording head
    Patent number: 9263086
    Abstract: A hard disk drive (HDD) is described which includes a magnetic field-generating device in the vicinity of a load/unload ramp such that the write head moves into a magnetic field generated by the device while the head is being unloaded from disk, whereby the magnetic field pins in a predominant direction the direction of magnetization of a magnetic shield associated with the write head, and away from the direction toward the disk. Recording magnetic field leakage associated with the shield is thereby suppressed and corresponding far track interference is inhibited.
    Type: Grant
    Filed: March 27, 2014
    Date of Patent: February 16, 2016
    Assignee: HGST Netherlands B.V.
    Inventors: Satoshi Tabata, Norifumi Miyamoto, Akira Morinaga, Masahiro Ito, Masahiko Hatatani
  • Recording medium and method of forming the same
    Patent number: 9251831
    Abstract: In various embodiments, a recording medium may be provided. The recording medium may include a servo layer. The recording medium may further include a data recording layer. The recording medium may additionally include a crystal-like soft underlayer (SUL). The data recording layer and the servo layer may be on a same side of the crystal-like soft underlayer.
    Type: Grant
    Filed: July 19, 2013
    Date of Patent: February 2, 2016
    Assignee: Marvell International Ltd.
    Inventors: Jianzhong Shi, Wee Kiat Lim
  • Symbol timing recovery scheme for parallel recording channel systems
    Patent number: 9251811
    Abstract: A method for symbol timing recovery is disclosed. The method comprises receiving a plurality of timing-error estimates for a plurality of read channels, where each of the timing-error estimates corresponds to one of the read channels. The method further comprises calculating a common phase based on the plurality of timing-error estimates, and calculating a skew of a transducer array based on the plurality of timing-error estimates. Finally, the method comprises calculating a different total phase estimate for each read channel based on the calculated common phase and the calculated skew of the transducer array.
    Type: Grant
    Filed: June 10, 2015
    Date of Patent: February 2, 2016
    Assignee: International Business Machines Corporation
    Inventors: Simeon Furrer, Robert A. Hutchins, Jens Jelitto, Mark A. Lantz
  • Data storage device measuring reader/writer offset by reading spiral track and concentric servo sectors
    Patent number: 9245560
    Abstract: A data storage device is disclosed comprising a disk comprising a spiral track, and a head actuated over the disk, wherein the head comprises a read element offset radially from a write element by a reader/writer offset. The spiral track is first read to write a plurality of concentric servo sectors on the disk that define at least one concentric servo track on the disk. The spiral track is second read and the concentric servo sectors are read to measure the reader/writer offset.
    Type: Grant
    Filed: March 9, 2015
    Date of Patent: January 26, 2016
    Assignee: Western Digital Technologies, Inc.
    Inventors: Jianbin Nie, Charles A. Park, Siri S. Weerasooriya
  • Magnetic head providing write protrusion suppression and methods of formation thereof
    Patent number: 9245581
    Abstract: A system includes a magnetic head, a magnetic medium, a drive mechanism for passing the magnetic medium over the magnetic head, and a controller electrically coupled to the magnetic head for controlling operation of the magnetic head, wherein the magnetic head has a write element, a read element, a substrate that is an alloy material having greater than about 50 at. % TiC, and a heater element positioned between the read element and the write element, the write element being positioned nearer to the substrate than the read element such that heat generated by the write element during write operations is dissipated by the substrate, and the heater element being adapted for inducing protrusion of portions of an air bearing surface (ABS) of the magnetic head to adjust a clearance between the portions of the ABS and the magnetic medium.
    Type: Grant
    Filed: June 11, 2013
    Date of Patent: January 26, 2016
    Assignee: HGST Netherlands B.V.
    Inventors: Koji Tanaka, Yoshinori Takeuchi
  • Apparatus and method for measuring surface charge of a slider
    Patent number: 9245561
    Abstract: An apparatus comprises a slider that includes a fly height sensor. A signal generator is coupled to the slider. The signal generator is configured to generate an AC electrical signal having a DC offset voltage and to adjust the DC offset of the AC electrical signal to a plurality of DC offset voltages. Circuitry is coupled to the fly height sensor and the signal generator. The circuitry is configured to measure fly height of the slider in response to application of the AC electrical signal with varying DC offset voltages to the slider. The circuitry is further configured to determine an extremum of the measured fly heights and generate an output that includes the DC offset voltage associated with the fly height extremum.
    Type: Grant
    Filed: March 24, 2015
    Date of Patent: January 26, 2016
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Ju Yong Lee, Won Choul Yang, Shi Jung Kim
  • Multi-disk writer with individual head positioning
    Patent number: 9236074
    Abstract: A system comprises a disk writer servo head and a controller. The disk writer servo head is configured to be positioned by a micro actuator. The disk writer servo head is also configured to substantially, continuously alternate between reading a first servo pattern and writing a second servo pattern until a disk is substantially, completely servo written. The first servo pattern establishes a first position of the disk writer servo head and the second servo pattern establishes a second position of the disk writer servo head. The controller is configured to control the operation of the disk writer servo head. The controller is also configured to compare the first and second positions to establish a position error. The micro actuator is configured to reposition the disk writer servo head in response to the position error prior to a next reading.
    Type: Grant
    Filed: January 26, 2015
    Date of Patent: January 12, 2016
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Michael R. Tiller, Barmeshwar Vikramaditya, Yongjun Hou
  • Atomic write-in-place for hard disk drives
    Patent number: 9236066
    Abstract: In general, techniques are described for writing data to a storage device that comprises an interface and a controller. The interface may receive a request to sequentially write data stored in a first group of tracks to an I-region, where the first group of tracks was also previously written. The controller may move data stored in a second group of consecutive tracks different than the first group of tracks from the I-region to an E-region, the second group having cardinality equal to the tracks that must be moved for the first group to be written sequentially in the I-region. The E-region comprises a portion of the storage device reserved for temporary storage. The controller may determine a position of the I-region where data from one of the second group was previously stored, and write data from the first group of tracks sequentially to the I-region, starting at the position.
    Type: Grant
    Filed: January 23, 2015
    Date of Patent: January 12, 2016
    Assignee: HGST Netherlands B.V.
    Inventors: Jonathan D. Coker, David R. Hall, Shad H. Thorstenson
  • Resistance temperature sensors for head-media and asperity detection
    Patent number: 9230594
    Abstract: A temperature sensor of a head transducer measures temperature near or at the close point. The measured temperature varies in response to changes in spacing between the head transducer and a magnetic recording medium. A detector is coupled to the temperature sensor and is configured to detect a change in a DC component of the measured temperature indicative of onset of contact between the head transducer and the medium. Another head transducer configuration includes a sensor having a sensing element with a high temperature coefficient of resistance to interact with asperities of the medium. Electrically conductive leads are connected to the sensing element and have a low temperature coefficient of resistance relative to that of the sensing element, such thermally induced resistance changes in the leads have a negligible effect on a response of the sensing element to contact with the asperities.
    Type: Grant
    Filed: May 27, 2014
    Date of Patent: January 5, 2016
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Gary Joseph Kunkel, Huazhou Lou, Declan Macken, Timothy William Stoebe
  • Per wedge preheat DFH to improve data storage device performance
    Patent number: 9230585
    Abstract: A disk drive is disclosed including a disk having a plurality of tracks, wherein each track comprises a plurality of data sectors and a plurality of servo sectors. The disk drive further comprises a spindle motor for rotating the disk, and a head actuated radially over the disk, wherein the head comprises a dynamic fly height (DFH) heater. Control circuitry within the disk drive is operable to position the head over one of the tracks; determine a number of servo sectors to pass under the head before a target location over the track is reached, apply an initial amount of power to the DFH heater that is dependent at least in part on the determined number of servo sectors, and decrease the initially-applied amount of power applied to the DFH heater until a predetermined target power is reached.
    Type: Grant
    Filed: January 31, 2014
    Date of Patent: January 5, 2016
    Assignee: Western Digital Technologies, Inc.
    Inventor: Huanxiang Ruan
  • Data storage device measuring radial offset between read element and write element
    Patent number: 9214186
    Abstract: A data storage device is disclosed comprising a disk comprising a plurality of tracks and a head actuated over the disk, wherein the head comprises a read element radially offset from a write element. A first pattern is written to a single track, and the first pattern is read from the single track to generate a first read signal from which a first quality metric is generated. A second pattern is written to the single track, wherein the second pattern is different from the first pattern. The second pattern is read from the single track to generate a second read signal from which a second quality metric is generated. The radial offset of the read element and write element is measured based on the first and second quality metrics.
    Type: Grant
    Filed: March 23, 2015
    Date of Patent: December 15, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventor: Phillip Scott Haralson
  • Adjusting rotation speed of disk to reduce fly height modulation when servo writing in gas
    Patent number: 9214188
    Abstract: A method is disclosed for selecting a rotation speed when servo writing a disk of a disk drive. A gas is injected into a head disk assembly (HDA) comprising the disk. The disk is rotated while reading data from the disk using a head to generate a read signal. A fly height modulation (FHM) of the head is measured in response to the read signal. When the FHM exceeds a threshold, the rotation speed is adjusted. The disk is servo written at the adjusted rotation speed. After servo writing the disk and evacuating the gas from the HDA, the disk is rotated at a normal rotation speed lower than the adjusted rotation speed used to servo write the disk, and manufacturing data is written to the disk at the normal rotation speed.
    Type: Grant
    Filed: March 12, 2010
    Date of Patent: December 15, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Jern Khang Tan, Amar Nath, Boworn Panyavoravaj
  • Data storage device attenuating interference from first spiral track when reading second spiral track
    Patent number: 9208810
    Abstract: A data storage device is disclosed comprising a disk surface comprising a first spiral track at least partially overwritten by a second spiral track, and a head actuated over the disk surface based on the second spiral track. The first spiral track comprises a periodic pattern written at a first frequency, and the second spiral track comprises a periodic pattern written at a second frequency different from the first frequency.
    Type: Grant
    Filed: December 4, 2014
    Date of Patent: December 8, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Jianbin Nie, Charles A. Park, Brian P. Rigney, Siri S. Weerasooriya
  • Electronic system with unload management mechanism and method of operation thereof
    Patent number: 9208808
    Abstract: An apparatus includes: a media; a head assembly over the media; a head actuation motor coupled to the head assembly; control circuitry, coupled to the head actuation motor, configured to position the head assembly; and a head loading ramp, adjacent to the media; wherein: the control circuitry is further configured to: generate a seek count; and park the head assembly, off of the media, on the head loading ramp, controlling a speed of the head actuation motor based on the seek count.
    Type: Grant
    Filed: June 16, 2014
    Date of Patent: December 8, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Jianghong Ding, Jenghung Chen, Wenli Yang
  • Method and apparatus for detecting proximity contact between a transducer and a medium
    Patent number: 9202495
    Abstract: A method and apparatus are provided for positioning a transducer relative to a track of a data storage medium and inducing lateral modulation of transducer the relative to the track. An element of the transducer is actuated toward the storage medium during the lateral modulation, and atomic interaction is detected between the element and the storage medium because of a change in a response to the lateral modulation of the transducer due to the atomic interaction.
    Type: Grant
    Filed: May 1, 2007
    Date of Patent: December 1, 2015
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Dongming Liu, Lin Zhou, Lance E. Stover
  • Tape drive with head assembly having dual offset devices
    Patent number: 9177580
    Abstract: A recording head assembly that includes two side-by-side and separately actuated heads. To increase tape capacity while controlling tape mis-registration, write elements are provided in two subsets with a first subset provided on a first of the two heads and a second subset provided on the second of the two heads. The two subsets are offset a distance along the direction of travel for a tape (or horizontal offset) while the two subsets of write elements are also offset along the longitudinal axes of the heads (or bumps on the heads) such that a first subset acts as the upper half of the write element set and a second subset acts as the lower half of the write element set. The subsets of write elements simultaneously writes data, and a similar arrangement can be provided for two subsets of read elements that are aligned with the write elements.
    Type: Grant
    Filed: March 16, 2015
    Date of Patent: November 3, 2015
    Assignee: ORACLE INTERNATIONAL CORPORATION
    Inventors: William J. Vanderheyden, Darryl Wayne Yeakley, Steven G. Trabert
  • Non-contact fly height calibration and compensation
    Patent number: 9177599
    Abstract: Calibration and calculation of thermal clearance compensation of a head in a storage device without causing contact between the head and a storage medium. The thermal clearance compensation may be configured to compensate for any changing fly height of the head of the storage device during different temperature conditions based on high and low temperature signal data.
    Type: Grant
    Filed: October 24, 2013
    Date of Patent: November 3, 2015
    Assignee: Seagate Technology LLC
    Inventors: Clifford Jayson Bringas Camalig, ChengYi Guo, Mui Chong Chai, Victor Chew Weng Khin, Lim TeckKhoon
  • Recording medium having independent track for velocity, timing and/or longitudinal position
    Patent number: 9171563
    Abstract: A product according to one embodiment includes a magnetic recording tape having at least one first servo track having timing information, and a supplemental servo track having at least one of: velocity encoding and longitudinal position encoding. An apparatus according to one embodiment includes a magnetic head and at least one module having an array of transducers. The apparatus is configured to read and/or write to magnetic recording media having at least one first servo track having timing information, and a supplemental servo track having at least one of: velocity encoding and longitudinal position encoding.
    Type: Grant
    Filed: September 30, 2014
    Date of Patent: October 27, 2015
    Assignee: International Business Machines Corporation
    Inventor: Robert G. Biskeborn
  • Systems and methods for clearance monitoring in storage media
    Patent number: 9159348
    Abstract: A method for measuring the head-disk clearance between a slider and a disk includes measuring a first resistance with a first bias applied to an embedded contact sensor of the slider, measuring a second resistance with a second bias applied to the embedded contact sensor of the slider, and determining the head-disk clearance based at least in part on a difference between the first resistance and the second resistance. A system includes a disk drive, a slider comprising an embedded contact sensor, and circuitry to apply at least two bias voltages to the embedded contact sensor, measure at least two resistances of the embedded contact sensor based on the application of the at least two bias voltages, and to determine the head-disk clearance based at least in part on a difference between the at least two resistances.
    Type: Grant
    Filed: December 17, 2013
    Date of Patent: October 13, 2015
    Assignee: HGST NETHERLANDS B.V.
    Inventors: Jianhua Li, Junguo Xu, Toshiya Shiramatsu, Takehiro Sato
  • Writer core incorporating thermal sensor having a temperature coefficient of resistance
    Patent number: 9159349
    Abstract: A writer core of a transducer is configured to interact with a magnetic recording medium and comprises an upper core and a lower core. At least one of the upper and lower cores comprises a return pole having a return shield. The apparatus also comprises a writer pole between the upper and lower cores, and a writer gap defined between the writer pole and the return shield. The apparatus further comprises a sensor element within one of the upper and lower cores that includes the writer gap. The sensor element has a temperature coefficient of resistance and is configured to sense for a change in temperature indicative of one or both of a change in spacing and contact between the transducer and the magnetic recording medium.
    Type: Grant
    Filed: August 28, 2013
    Date of Patent: October 13, 2015
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Peng Peng, Declan Macken, Michael Thomas Johnson, Zheying Guo
  • Device for detecting a percussion event, and associated mobile system
    Patent number: 9151777
    Abstract: The device for detecting percussion events (DISP) comprises at least one axial accelerometer sensor (ACC1, ACC2, ACC3), characterized in that it also comprises at least one additional axial sensor insensitive to the translational vibrations (MAGN1, MAGN2), for measuring an information item representative of the orientation of the device (DISP) relative to a vector field of known direction within a fixed coordinate system not linked to the device (DISP), and low cut-off filtering means (FILTCB) provided with at least one input receiving measurements transmitted by the axial sensor or sensors (ACC1, ACC2, ACC3, MAGN1, MAGN2), means (AN) of analyzing the measurements filtered by said low cut-off filtering means (FILTCB), comprising comparison means (COMP) for comparing data from the analysis means (AN) with one or two thresholds (SP, SN).
    Type: Grant
    Filed: July 31, 2008
    Date of Patent: October 6, 2015
    Assignee: MOVEA
    Inventor: Yanis Caritu
  • Data storage device measuring laser protrusion fly height profile
    Patent number: 9153266
    Abstract: A data storage device is disclosed comprising a disk comprising a plurality of tracks, where each track comprises a plurality of servo sectors and at least one data segment between consecutive servo sectors. The data storage device further comprises a head actuated over the disk, the head comprising a laser configured to heat the disk during write operations based on a laser power. During a first revolution of the disk, the laser power is first increased over a first interval to cause at least part of the head to protrude toward a first data segment of the disk. After the first interval, the laser power is decreased and a fly height pattern is read from the first data segment to first measure a fly height of the head.
    Type: Grant
    Filed: September 11, 2014
    Date of Patent: October 6, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Galvin T. Chia, Davide Giovenzana, Teik Ee Yeo
  • Motor drive device, magnetic disk storage device, and electronic device
    Patent number: 9142248
    Abstract: A motor drive device has a spindle motor driver adapted to receive electric power from a power supply line to drive a spindle motor; an isolation switch adapted to connect and disconnect an application terminal of a power supply voltage to and from the power supply line, and a current monitor adapted to monitor a first current flowing into the isolation switch.
    Type: Grant
    Filed: April 5, 2013
    Date of Patent: September 22, 2015
    Assignee: ROHM CO., LTD.
    Inventor: Yoshito Otaguro
  • Clock accuracy determining method and clock accuracy determining device
    Patent number: 9129629
    Abstract: According to one embodiment, when a timing error between a signal read back from a multi-spiral pattern pre-recorded on a magnetic disc and an SSW clock generated at a read/write channel is set as an SSW clock following error, SSW clock accuracy is determined based on results of comparison between SSW clock following errors read from two different points in each of spiral patterns constituting the multi-spiral pattern.
    Type: Grant
    Filed: May 16, 2014
    Date of Patent: September 8, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Yutaka Yoshida
  • Loop pulse estimation-based fly height detector
    Patent number: 9129632
    Abstract: An apparatus for storing data includes a storage medium, a head assembly disposed in relation to the storage medium and operable to read and write data on the storage medium, a loop pulse estimation circuit operable to estimate a channel impulse response based on the data read by the head assembly, and a fly height detection circuit operable to detect a spacing between the head assembly and the storage medium based at least in part on the channel impulse response.
    Type: Grant
    Filed: October 27, 2014
    Date of Patent: September 8, 2015
    Assignee: AVAGO TECHNOLOGIES GENERAL IP (SINGAPORE) PTE. LTD.
    Inventor: Xiufeng Song
  • Methods and devices for head-media contact detection
    Patent number: 9123371
    Abstract: In certain embodiments, a head-suspension assembly includes a resonator attached to either a head or gimbal. The resonator is configured to resonate at a predefined resonant frequency. In certain embodiments, disc drives includes a recording medium, a head-suspension assembly, and a resonator. The resonator is attached to either a head or gimbal of the head-suspension assembly. The resonator is configured to resonate at a predefined resonant frequency.
    Type: Grant
    Filed: October 10, 2013
    Date of Patent: September 1, 2015
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Huazhou Lou, Lin Zhou, Vincent Engelkes
  • Data storage device with HGSA offset compensation
    Patent number: 9123368
    Abstract: A data storage device may be configured at least with an actuating assembly that has a head-gimbal suspension assembly (HGSA), first pivot point, and second pivot point. The head-gimbal assembly can be constructed and operated with at least first and second transducers aligned along a longitudinal axis of the head-gimbal suspension assembly. A controller may be adopted to manipulate the head-gimbal suspension assembly about at least one of the pivot points in response to a head-gimbal suspension assembly offset misalignment to compensate for such an offset.
    Type: Grant
    Filed: October 29, 2013
    Date of Patent: September 1, 2015
    Assignee: Seagate Technology LLC
    Inventors: Tzung-Sz Shen, Chih-Wu Jen
  • Electronic emergency-stop braking circuit for robotic arms
    Patent number: 9114536
    Abstract: Representative embodiments of a system for braking a cyclically rotating motor upon a power failure include (i) charge-storage circuitry for storing charge and converting the stored charge to an output voltage upon power failure; (ii) one or more passive electrical elements for conducting current induced by motor rotations; and (iii) voltage-actuated circuitry connected to the passive electrical element and the charge-storage circuitry for braking the motor during each half-cycle of motor rotation. The circuitry is inactive until actuated by the charge-storage circuitry upon power failure.
    Type: Grant
    Filed: April 13, 2012
    Date of Patent: August 25, 2015
    Assignee: Rethink Robotics, Inc.
    Inventor: Michael Sussman
  • Power management of a storage device including multiple processing cores
    Patent number: 9110669
    Abstract: A method of managing power of the storage device including a first processing core for controlling a first function block and a second processing core for controlling a second function block includes: analyzing a pattern of commands received from the outside; selecting an operation mode of the storage device based on the analyzed pattern; and managing the electric power of the storage device by using the first processing core if the selected operation mode is a first mode, and separately managing electric powers of the first and second function blocks by using the first and second processing cores, respectively, if the selected operation mode is a second mode.
    Type: Grant
    Filed: June 22, 2012
    Date of Patent: August 18, 2015
    Assignee: SAMSUNG ELECTRONICS CO., LTD.
    Inventor: Myung-Hyun Jo
  • Asperity and head-media contact detection using multi-stage temperature coefficient of resistance sensor
    Patent number: 9111572
    Abstract: A multi-stage sensor is situated on the head transducer and configured to interact with a magnetic recording medium. A first sensor stage of the multi-stage sensor has a temperature coefficient of resistance. A second sensor stage of the multi-stage sensor is coupled to the first sensor and has a temperature coefficient of resistance. The first sensor stage is configured to preferentially sense asperities of the media relative to the second sensor stage, and the second sensor stage configured to preferentially sense proximity to, and contact with, a surface of the media relative to the first sensor stage. The first and second sensor stages may be connected in series or in parallel.
    Type: Grant
    Filed: May 27, 2014
    Date of Patent: August 18, 2015
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Gary Joseph Kunkel, John L. Brand
  • Return control circuitry for VCM
    Patent number: 9099944
    Abstract: To provide a disk drive capable of inhibiting the occurrence of acoustic noise caused by a voltage pulse when the head is retracted using a speed control method using voltage obtained by rectifying a back electromotive force after the power source has been cut off from the rotation of a spindle motor. Retraction control circuit is used to control the on and off modes of transistors in accordance with the speed of VCM. The voltage across VCM becomes a voltage that can be regulated with VCM voltage control circuit. At this time, voltage is supplied to the terminals based on the voltage of ISO5V that is the rectified voltage of the back electromotive force of the spindle motor and the pulsating voltage is synchronized and produced at both terminals. As a result, the potential difference across VCM is such that the pulsating voltage is negated and acoustic noise is inhibited.
    Type: Grant
    Filed: March 26, 2014
    Date of Patent: August 4, 2015
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Masaki Yamashita, Chisako Asaoka, Nobuhiko Wasa
  • Data storage device employing multiple jog profiles for a butterfly written disk surface
    Patent number: 9099134
    Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of data tracks, wherein the head comprises a write element radially offset from a read element by a writer/reader offset that varies relative to a radial location of the head over the disk. A first radial band (RB) of the data tracks is written from an outer diameter (OD) of the disk toward an inner diameter (ID) of the disk, and a first jog profile is calibrated for the first radial band that compensates for the writer/reader offset. A second RB is written from an ID to an OD, and a second jog profile is calibrated for the second RB that compensates for the writer/reader offset. The first RB is accessed using the first jog profile, and the second RB is accessed using the second jog profile.
    Type: Grant
    Filed: January 27, 2015
    Date of Patent: August 4, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Suruk Pattanasinth, Margaret Wong, Paul C. Santa Ana, Xing Huo, Kameron Kam-Wai Jung
  • Motor drive device, magnetic disk storage device, and electronic appliance
    Patent number: 9093106
    Abstract: A motor drive device has a motor driver adapted to receive a first power supply voltage to drive a motor; an internal regulator adapted to generate from an input voltage an internal power supply voltage; and a power supply switcher adapted to receive both the first power supply voltage and a second power supply voltage lower than the first power supply voltage to output, as the input voltage, the second power supply voltage when the second power supply voltage is normal and to output, as the input voltage, the first power supply voltage when the second power supply voltage is abnormal.
    Type: Grant
    Filed: April 5, 2013
    Date of Patent: July 28, 2015
    Assignee: ROHM CO., LTD.
    Inventor: Yoshito Otaguro
  • Glass substrate for magnetic disk and magnetic recording medium
    Patent number: 9082443
    Abstract: With regard to a glass substrate 1 according to the present invention, a value of an amendment concentricity AC that has taken into consideration Sk and/or Ku calculated from a shape profile over the whole circumference of an inside hole, or the skewness is within a predetermined range. The glass substrate for a magnetic recording medium can stably read servo information including track information stored on a magnetic disk when the glass substrate is used for an HDD.
    Type: Grant
    Filed: October 4, 2012
    Date of Patent: July 14, 2015
    Assignee: HOYA CORPORATION
    Inventor: Kenichi Nishimori
  • Using first and second resistive sensor bias levels to detect head-to-disk contact and/or clearance
    Patent number: 9082440
    Abstract: A bias signal is applied to a resistive thermal sensor located proximate a magnetic media reading surface of a magnetic sensor. The bias signal is modulated between first and second bias levels. First and second resistances of the resistive thermal sensor corresponding to the first and second bias levels are measured. Based a difference between the first and second resistances caused by in increase in thermal conductivity between the magnetic sensor and a medium as the magnetic head gets closer to the medium, at least one of a spacing and a contact between the magnetic sensor and the medium are determined.
    Type: Grant
    Filed: July 23, 2012
    Date of Patent: July 14, 2015
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Michael Thomas Johnson, Manuel Charles Anaya Dufresne, Xuan Zheng, Dongming Liu
  • Fall detection scheme using FFS
    Patent number: 9076471
    Abstract: For a disk drive involving a disk; a head; and control circuitry having a servo control system operable to actuate the head, the control circuitry may be configured to determine a magnitude of acceleration readings, the acceleration readings involving at least three degrees of freedom, wherein when a magnitude of the acceleration readings is less than a first threshold, the control circuitry confirms a free fall, wherein when the magnitude is between the first and second threshold, the control circuitry confirms a tilt drop. During the tilt drop and the free fall, the control circuitry is further configured to actuate the head to park and monitor the shock impact.
    Type: Grant
    Filed: September 26, 2013
    Date of Patent: July 7, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Min Chen, Sanghoon Chu, Jifang Tian, Zhongjie Li, Hien T. Chu
  • Data storage device attenuating thermal decay effect on fly height measurement
    Patent number: 9076474
    Abstract: A data storage device is disclosed comprising a head actuated over a disk. A first spacing pattern is written to the disk and a second spacing pattern is written to the disk different from the first spacing pattern. A first fly height measurement (FHM1_1) is generated by reading the first spacing pattern and a first fly height measurement (FHM2_1) is generated by reading the second spacing pattern. After an interval, a second fly height measurement (FHM1_2) is generated by reading the first spacing pattern and a second fly height measurement (FHM2_2) is generated by reading the second spacing pattern. A change in the fly height of the head is estimated based on: (?FHM2?B·?FHM1)/(A?B) where ?FHM1 represents a difference between FHM1_1 and FHM1_2, ?FHM2 represents a difference between FHM2_1 and FHM2_2, and A and B are constants.
    Type: Grant
    Filed: December 23, 2014
    Date of Patent: July 7, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Kathy X. Tang, Jerry G. Le
  • Writable servo overlap zones
    Patent number: 9070411
    Abstract: Systems and methods are disclosed for writable servo zone overlap regions on a disc memory. An apparatus may comprise a controller configured to determine a servo gate (sgate) timing for an overlap zone including servo patterns of a first servo super zone and a second servo super zone of a disc memory, the sgate timing based on servo pattern timing for the first servo super zone and the second servo super zone. The controller may initiate writing to the overlap zone based on the sgate timing. The controller may also reduce the impact of servo pattern frequency change between zones by calculating a trajectory error prior to the crossing, and providing 1/X of the trajectory error into a servo feedback loop for a following X servo sampling points.
    Type: Grant
    Filed: July 4, 2013
    Date of Patent: June 30, 2015
    Assignee: Seagate Technology LLC
    Inventors: Timothy Ellis, Joshua W. Christensen, Ravi Hebbar, John Purkett, Justin Won
  • Spiral band end detection
    Patent number: 9064517
    Abstract: Systems and techniques relating to servo systems include, according to an aspect, a method includes: causing writing of a band of spirals including a first spiral set and a second spiral set onto a storage medium; determining one or more characteristics associated with the band of spirals; identifying one or more spirals of the band of spirals that meet the one or more determined characteristics; and determining an end of the band of spirals based on the one or more identified spirals. The method can further include causing writing of servo information onto the storage medium while track following on the band of spirals; causing terminating of the writing of the servo information upon determining the end of the band of spirals; and causing writing of another band of spirals starting at the end of the previous band of spirals.
    Type: Grant
    Filed: June 20, 2014
    Date of Patent: June 23, 2015
    Assignee: Marvell International Ltd.
    Inventors: Perry Neos, Luan Ton-That, Man Cheung
  • Image processing apparatus and method for controlling the same
    Patent number: 9065941
    Abstract: An information processing apparatus includes a hard disk unit, a control unit configured to output an instruction to retract a head of the hard disk unit, a monitoring unit configured to monitor a state of the control unit and output, in a case where the monitoring unit determines that the control unit cannot issue the instruction, an instruction to retract the head of the hard disk unit, and a hard disk controller configured to receive the instruction from the control unit or the monitoring unit and to issue a command for retracting the head of the hard disk unit to the hard disk unit. The hard disk unit retracts the head of the hard disk unit in a case where the hard disk unit receives the command.
    Type: Grant
    Filed: July 23, 2013
    Date of Patent: June 23, 2015
    Assignee: Canon Kabushiki Kaisha
    Inventor: Hiroyuki Tsuji
  • Disk drive measuring a resonance mode by injecting sinusoids into a servo control system
    Patent number: 9052701
    Abstract: A disk drive is disclosed comprising a disk comprising a plurality of servo tracks defined by servo sectors recorded around the circumference of the disk at a servo sampling frequency, and a servo control system operable to actuate a head over the disk by generating a control signal applied to an actuator. A first sinusoid is injected into the servo control system and a first DC component (dc1) is measured in the control signal. A second sinusoid is injected into the servo control system and a second DC component (dc2) is measured in the control signal, wherein the second sinusoid comprises a phase offset from the first sinusoid. A resonance mode of the servo control system is measured based on dc1 and dc2.
    Type: Grant
    Filed: August 14, 2012
    Date of Patent: June 9, 2015
    Assignee: Western Digitial Technologies, Inc.
    Inventors: Qingwei Jia, Shuyu Cao, Guoxiao Guo, Jie Yu
  • Nonlinearity-based contact prediction
    Patent number: 9053729
    Abstract: Various embodiments of a method of detecting a contact event between a head and a storage medium, and a storage device that utilizes such method are disclosed. In one or more embodiments, the method includes applying an input signal to an actuator of a head of a storage device; identifying a frequency of the input signal; detecting an output signal in response to the input signal; and detecting a contact event between the head and a storage medium of the storage device if the output signal includes an even harmonic frequency and an odd harmonic frequency of the frequency of the input signal.
    Type: Grant
    Filed: July 23, 2014
    Date of Patent: June 9, 2015
    Assignee: Seagate Technology LLC
    Inventors: Vijay Kumar, Ravishankar A. Shivarama
  • Extended cavity VCSEL mounted to substrate with electrical and thermal contact to substrate and optical power directed toward substrate
    Patent number: 9053731
    Abstract: A system according to one embodiment includes a slider adapted for use in a hard disk drive; and a laser coupled to a slider, wherein electrical contacts of the laser are positioned towards or face the slider, wherein light from the laser is emitted towards the slider, wherein the slider acts as a heat sink for the laser.
    Type: Grant
    Filed: February 23, 2011
    Date of Patent: June 9, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: Toshiki Hirano, Fu-Ying Huang, Jia-Yang Juang, Barry Cushing Stipe
  • Disk drive opening spiral crossing window based on DC and AC spiral track error
    Patent number: 9053727
    Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of spiral tracks including a first spiral track. A DC spiral track error common to the spiral tracks is measured relative to an ideal slope for the spiral tracks, and an AC spiral track error is measured for each spiral track relative to the ideal slope. As the head approaches the first spiral track, a spiral crossing window is opened based on the measured DC spiral track error and the measured AC spiral track error for the first spiral track, and the first spiral track is detected after opening the spiral crossing window.
    Type: Grant
    Filed: June 2, 2014
    Date of Patent: June 9, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Jianbin Nie, Brian P. Rigney, Edgar D. Sheh
  • High-speed recording disk defect detection
    Patent number: 9053725
    Abstract: A hard disk drive electronic component processes a signal from a piezoelectric actuator to identify where on a disk the slider encounters a disk defect. The signal received from the piezoelectric actuator may be based on the mechanical propagation, through the suspension to the piezoelectric actuator, of an effect of slider contact with the protrusion. Further, an actuator may be commanded to systematically move the head slider across the writeable portion of the disk to map all the protrusions on the writeable portion of the disk.
    Type: Grant
    Filed: August 25, 2014
    Date of Patent: June 9, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: Yuichiro Sano, Junguo Xu, Yuka Morimoto
  • Disk drive comprising extended range head proximity sensor
    Patent number: 9053730
    Abstract: A disk drive is disclosed comprising a head actuated over a disk, and a fly height transducer operable to generate a fly height signal for the head. The disk drive further comprises control circuitry comprising a current sensor operable to detect a current flowing through the fly height transducer. The current sensor comprises a differential amplifier operable to amplify the current flowing through the fly height transducer over a first range using a first gain, and amplify the current flowing through the fly height transducer over a second range using a second gain less than the first gain, wherein at least part of the second range is different than the first range.
    Type: Grant
    Filed: February 20, 2014
    Date of Patent: June 9, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventor: Dennis W. Hogg
  • Disk drive measuring fly height by applying a bias voltage to an electrically insulated write component of a head
    Patent number: 9042208
    Abstract: A disk drive is disclosed comprising a disk, and a slider comprising a head, where the head comprises a write component electrically insulated from the slider. A bias voltage is applied to the write component, and a current flowing between the write component and the disk is measured, wherein the current is indicative of a fly height of the head.
    Type: Grant
    Filed: March 11, 2013
    Date of Patent: May 26, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Bernhard E. Knigge, Jian Xu, Lisha Wang, Dennis W. Hogg
  • Head transducer with multiple resistance temperature sensors for head-medium spacing and contact detection
    Patent number: 9042050
    Abstract: A head transducer, configured to interact with a magnetic recording medium, includes a first sensor having a temperature coefficient of resistance (TCR) and configured to produce a first sensor signal, and a second sensor having a TCR and configured to produce a second sensor signal. One of the first and second sensors is situated at or near a close point of the head transducer in relation to the magnetic recording medium, and the other of the first and second sensors spaced away from the close point. Circuitry is configured to combine the first and second sensor signals and produce a combined sensor signal indicative of one or both of a change in head-medium spacing and head-medium contact. Each of the sensors may have a TCR with the same sign (positive or negative) or each sensor may have a TCR with a different sign.
    Type: Grant
    Filed: August 12, 2014
    Date of Patent: May 26, 2015
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Michael Thomas Johnson, Dongming Liu, Huazhou Lou, Declan Macken, Timothy William Stoebe, James Gary Wessel, Xuan Zheng