By Nonmagnetic Sensing (e.g., Optical, Capacitive) Patents (Class 360/77.03)
  • Patent number: 10361645
    Abstract: A method for identifying an error state in a brushless direct current motor. For the purposes of this identification, an angle deviation between a shaft angle and a control angle is calculated and used to identify error states on the basis of characteristic patterns. This also works, in particular, for slowly-rotating or stationary brushless direct current motors and allows a clear reduction in the calculation capacities required, compared to the prior art.
    Type: Grant
    Filed: September 24, 2015
    Date of Patent: July 23, 2019
    Assignee: Continental Automotive GmbH
    Inventors: Christian Gunselmann, Frank Sader
  • Patent number: 10229706
    Abstract: A slider of a heat-assisted magnetic recording head comprises an air bearing surface and an optical waveguide configured to receive light from a laser source. The slider comprises a plurality of electrical bond pads including a first bond pad and a second bond pad. A first resistive sensor is configured to sense for spacing changes and contact between the slider and a magnetic recording medium at or near a first close point of the slider. A second resistive sensor is configured to sense for spacing changes and contact between the slider and the medium at or near a second close point of the slider. A bolometer is situated at a location within the slider that receives at least some of the light communicated along the optical waveguide. The first resistive sensor, the second resistive sensor, and the bolometer are coupled together and between the first and second bond pads.
    Type: Grant
    Filed: April 23, 2018
    Date of Patent: March 12, 2019
    Assignee: Seagate Technology LLC
    Inventors: Declan Macken, Jon Karsten Klarqvist
  • Patent number: 9972350
    Abstract: A slider of a heat-assisted magnetic recording head comprises an air bearing surface and an optical waveguide configured to receive light from a laser source. The slider comprises a plurality of electrical bond pads including a first bond pad and a second bond pad. A first resistive sensor is configured to sense for spacing changes and contact between the slider and a magnetic recording medium at or near a first close point of the slider. A second resistive sensor is configured to sense for spacing changes and contact between the slider and the medium at or near a second close point of the slider. A bolometer is situated at a location within the slider that receives at least some of the light communicated along the optical waveguide. The first resistive sensor, the second resistive sensor, and the bolometer are coupled together and between the first and second bond pads.
    Type: Grant
    Filed: August 16, 2017
    Date of Patent: May 15, 2018
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Declan Macken, Jon Karsten Klarqvist
  • Patent number: 9784756
    Abstract: A method of measuring feeding velocity of a web, on which a scale having pitches different from pitches of a mask are formed, is provided. The method includes: calculating a number of vibrations of a moiré image of light passing through the mask and the scale; calculating pitches of the scale of the fed web based on the calculated number of vibrations of the moiré image; averaging the pitches of the scale so that a change in a pitch between adjacent timings among the calculated pitches of the scale is minimized; extracting first signals corresponding to our phases for one pitch based on the averaged pitches of the scale; calculating two second signals for forming a Lissajous circle from the first signals; and calculating an angle of the Lissajous circle by the two second signals and then calculating the feeding velocity of the web by using the calculated angle.
    Type: Grant
    Filed: May 9, 2014
    Date of Patent: October 10, 2017
    Assignee: KOREA INSTITUTE OF MACHINERY & MATERIALS
    Inventors: Dongwoo Kang, Taik Min Lee, Seung-Hyun Lee, Young Man Choi, Deokkyun Yoon, Kwang-Young Kim, Jeongdai Jo
  • Patent number: 9692341
    Abstract: An apparatus for detecting speed of a motor is disclosed, the apparatus including an amplifier configured to amplify a two-phase sine-wave signal inputted from an encoder based on rotation of a motor; a first conversion unit configured to convert the two-phase sine-wave signal to a digital data; a second conversion unit configured to convert the two-phase sine-wave signal to a square-wave signal; a counter unit configured to accumulate by counting the square-wave signal; and a speed determination unit configured to determine a speed of the motor, by receiving the digital data from the first conversion unit and the accumulated count from the counter unit.
    Type: Grant
    Filed: March 5, 2015
    Date of Patent: June 27, 2017
    Assignee: LSIS CO., LTD.
    Inventor: Min Hun Chi
  • Patent number: 9666219
    Abstract: Determining quality metrics of a magnetic tape recording medium. A production module that includes a write element that writes magnetic transitions to the magnetic tape is substantially in constant physical engagement with the magnetic tape. A supplemental module that includes one or more read elements periodically physically engages the magnetic tape, and the read elements generate an electrical signal corresponding to transitions written to the magnetic recording medium by a write element. A computer receives information representative of the electrical signal and determines if a quality metric of the magnetic recording medium derived from the electrical signal is within a defined range. If the quality metric is not within the defined range, a defined action is performed by the computer.
    Type: Grant
    Filed: March 28, 2016
    Date of Patent: May 30, 2017
    Assignee: International Business Machines Corporation
    Inventors: Robert G. Biskeborn, Calvin S. Lo, Tak H. Wong, Xu Yan
  • Patent number: 9455656
    Abstract: A method of estimating the position of a rotor of an electric motor comprises producing an output signal indicative of motor position using a position sensor which comprises a detector and at least one encoder which rotates along with the rotor of the motor and includes a plurality of encoding regions, the output signal of the sensor varying in a stepwise fashion as the encoding regions move past the detector, and passing the output of the sensor through a smoothing algorithm to produce an estimated position signal, the algorithm being arranged to smooth the transition between the steps in the output of the sensor by causing the estimated position signal to lag behind the output of the sensor following a step change in the output of the sensor.
    Type: Grant
    Filed: November 27, 2013
    Date of Patent: September 27, 2016
    Assignee: TRW Limited
    Inventors: Christopher David Dixon, Robert James Huxford
  • Patent number: 9389101
    Abstract: A readhead control mechanism serves to control a readhead included in an optical encoder that measures a mechanical displacement between a fixed portion and a movable portion by reading out a gradation mark on a scale provided on the fixed portion, by using the readhead that is provided on the movable portion. The readhead mechanism includes a securing member that secures the readhead onto the movable portion, an actuator that is directly or indirectly secured onto the readhead to shift the readhead in an approaching direction or in a distancing direction, and an actuator controller that controls the actuator to maintain a constant distance between the readhead and the scale.
    Type: Grant
    Filed: March 20, 2013
    Date of Patent: July 12, 2016
    Assignee: Mitsubishi Electric Corporation
    Inventors: Yutaka Ezaki, Noboru Itoh
  • Patent number: 9330714
    Abstract: A supplemental module that includes one or more read elements periodically engages a magnetic recording medium, and the read elements generate an electrical signal corresponding to transitions written to the magnetic recording medium by a write element. A computer receives information representative of the electrical signal and determines if a quality metric of the magnetic recording medium derived from the electrical signal is within a defined range. If the quality metric is not within the defined range, a defined action is performed by the computer.
    Type: Grant
    Filed: August 5, 2015
    Date of Patent: May 3, 2016
    Assignee: International Business Machines Corporation
    Inventors: Robert G. Biskeborn, Calvin S. Lo, Tak H. Wong, Xu Yan
  • Patent number: 9131848
    Abstract: An optical probe is provided. The optical probe includes a lens extending along an axis between a first end and a second end. A spacer extends along the axis between a first end and a second end. The first end of the spacer is connected to the second end of the lens. A prism is connected to the second end of the spacer such that the prism is spaced apart from the lens by the spacer.
    Type: Grant
    Filed: August 1, 2013
    Date of Patent: September 15, 2015
    Assignee: NINEPOINT MEDICAL, INC.
    Inventor: Matthew A. Sinclair
  • Patent number: 8687943
    Abstract: The application manager 37 conducts “application signaling” when a first disc is replaced with a second disc. At this point, an application is continued if it is written in an application management table assigned to a Title played last on a first disc and also written in an application management table assigned to a Title to be played first on a second disc. On the other hand, an application is ended is it is written in the application management table assigned to the Title played last on the first disc but not written in the application management table assigned to the Title to be played first on the second disc.
    Type: Grant
    Filed: August 19, 2011
    Date of Patent: April 1, 2014
    Assignee: Panasonic Corporation
    Inventor: Wataru Ikeda
  • Patent number: 8456643
    Abstract: A method and system for determining a shape of a portion of an air-bearing surface (ABS) of a head residing on a slider are described. The ABS is configured to fly at a fly height from and with a velocity with respect to a disk during normal operating conditions. The method and system include driving at least one heater residing in the head while the slider is substantially at the normal operating conditions with respect to the disk and the fly height. The shape of the portion of the ABS changes in response to the heater(s) being driven. The method and system also include performing Doppler measurements on the slider while the heater is driven. The shape may then be determined based on the Doppler measurements.
    Type: Grant
    Filed: September 20, 2010
    Date of Patent: June 4, 2013
    Assignee: Western Digital (Fremont), LLC
    Inventors: Vijay Prabhakaran, Wuxing Gan, Ladislav R. Pust, David E. Fowler, Lanshi Zheng
  • Patent number: 8456976
    Abstract: There is disclosed herein a method and apparatus for centering a disk on a spindle, a spinstand and a method of testing with a spinstand. The method of centering includes attaching the disk to the spindle with a stick-slip clamp. A vector is determined by which the centre of the disk is displaced from the spindle axis and the vector is aligned with a movably mounted piezo actuator. A voltage is then applied to the piezo actuator to cause the piezo actuator to apply an impulse to the edge of the disk to cause the disk to slip in the clamp and reduce the displacement of the disk.
    Type: Grant
    Filed: January 4, 2012
    Date of Patent: June 4, 2013
    Assignee: Xyratex Technology Limited
    Inventors: Nicholas John Granger-Brown, Martin Siering
  • Patent number: 8437099
    Abstract: A hard disk drive includes a housing including a base member and a cover member, a spindle motor disposed in the housing, a data storage disk disposed on the spindle motor, an actuator disposed in the housing to move a read/write head to a position on the data storage disk, a clock signal providing unit disposed on the data storage disk to provide a clock signal of the data storage disk, a position signal providing unit disposed on the actuator to provide a position signal of the actuator, and first and second windows disposed in the housing to correspond to the clock signal providing unit and the position signal providing unit.
    Type: Grant
    Filed: April 29, 2009
    Date of Patent: May 7, 2013
    Assignee: Seagate Technology LLC
    Inventors: Kyung-ho Kim, Dong-ho Oh, Ha-yong Kim, Sung-joon Han, Kwang-jo Jung
  • Patent number: 8437100
    Abstract: Systems and methods for flexure based shock and vibration sensor for head suspensions in hard disk drives. Specifically, this invention deals with operational shock and vibration management within a hard disk drive. In one implementation, the assembly includes a circuit embedded optical waveguide sensor that includes a flexible electrical circuit board with a configuration of either a single or multi layers of conductor traces, a thin flexure gimbal for carrying and flying a HDD slider, a consecutive sensing layer constructed by an optical core and by clad construction with a configuration of either a single core array or a plural core array, an optical loop formed by light input and an output core, optical grating disposed on the consecutive sensing layer forming an optical grating waveguide sensor, a light emitter for injecting light into the optical core, and a receiver receiving the output light from the optical core.
    Type: Grant
    Filed: April 18, 2012
    Date of Patent: May 7, 2013
    Assignee: Nitto Denko Corporation
    Inventors: Martin John McCaslin, Visit Thaveeprungsriporn, Szu-Han Hu
  • Publication number: 20120194945
    Abstract: Cross-track deviation of a writer from a predetermined track on a recording medium is detected. A write current is adjusted based on the cross-track deviation of the writer from the predetermined track. The adjusted write current is applied to the writer to compensate for the cross-track deviation of the writer from the predetermined track.
    Type: Application
    Filed: February 2, 2011
    Publication date: August 2, 2012
    Applicant: Seagate Technology LLC
    Inventor: Kaizhong Gao
  • Publication number: 20120147495
    Abstract: A storage system includes a first buffer configured to store a first repeatable runout profile (RRP) for a sector of a rotating storage medium. A second buffer is configured to store a second RRP for the sector. A controller: controls a servo of the rotating storage medium based on the first RRP during a first revolution of the rotating storage medium; and learns the second RRP (i) while operating in a track-following mode, and (ii) during the first revolution. The controller ceases learning of the second RRP when one of (i) the controller is operating in a seek mode and (ii) the rotating storage medium is in an off-track state. Subsequent to the first revolution of the rotating storage medium and based on whether the learning of the second RRP was stopped during the first revolution, the controller replaces the first RRP with the second RRP in the first buffer.
    Type: Application
    Filed: February 20, 2012
    Publication date: June 14, 2012
    Inventors: Pantas Sutardja, Yuan Zheng, Yong Huang, Qiuliang Fu
  • Patent number: 8182705
    Abstract: A method for producing a thin film magnetic head including a magnetoresistive effect element (MR element) that has a magnetic sensor multi-layered film with a polygonal shape such that a vertex angle faces an air bearing surface (ABS) and a tip of the vertex angle is cut when the magnetic sensor multi-layered film is viewed from an X-Y plane that is parallel to a plane of a lower shield electrode layer includes a step for stopping a lapping process by using a measurement point in which a resistance value is steeply increased while the lapping face is gradually approaching the vertex angle of polygonal shape by lapping from the ABS side. Therefore, an excellent effect in which an ultra narrow track width that exceeds limits of photolithography technology can be securely and constantly formed is obtained.
    Type: Grant
    Filed: October 30, 2009
    Date of Patent: May 22, 2012
    Assignee: TDK Corporation
    Inventors: Kosuke Tanaka, Daisuke Miyauchi, Takumi Yanagisawa
  • Patent number: 8179629
    Abstract: Systems and methods for flexure based shock and vibration sensor for head suspensions in hard disk drives. Specifically, this invention deals with operational shock and vibration management within a hard disk drive. In one implementation, the assembly includes a circuit embedded optical waveguide sensor that includes a flexible electrical circuit board with a configuration of either a single or multi layers of conductor traces, a thin flexure gimbal for carrying and flying a HDD slider, a consecutive sensing layer constructed by an optical core and by clad construction with a configuration of either a single core array or a plural core array, an optical loop formed by light input and an output core, optical grating disposed on the consecutive sensing layer forming an optical grating waveguide sensor, a light emitter for injecting light into the optical core, and a receiver receiving the output light from the optical core.
    Type: Grant
    Filed: November 26, 2008
    Date of Patent: May 15, 2012
    Assignee: Nitto Denko Corporation
    Inventors: Martin John McCaslin, Visit Thaveeprungsriporn, Szu-Han Hu
  • Patent number: 8059518
    Abstract: Disclosed are a data storage apparatus, an assembling method thereof and an apparatus for generating a tracking position error signal capable of storing data using recording media formed with patterns for generating tracking position error signals to obviate errors that may be generated amidst storage of the data, wherein the patterns are formed for generating tracking position error signals on recording media before the recording media and storage are assembled to reduce the manufacturing cost and manufacturing process time.
    Type: Grant
    Filed: March 4, 2008
    Date of Patent: November 15, 2011
    Assignee: LG Electronics Inc.
    Inventors: Choong Woo Lee, Young Sik Kim, Jun Moon, Ji Young Jeong, Chung Choo Chung
  • Patent number: 8032007
    Abstract: The application manager 37 conducts “application signaling” when a first disc is replaced with a second disc. At this point, an application is continued if it is written in an application management table assigned to a Title played last on a first disc and also written in an application management table assigned to a Title to be played first on a second disc. On the other hand, an application is ended is it is written in the application management table assigned to the Title played last on the first disc but not written in the application management table assigned to the Title to be played first on the second disc.
    Type: Grant
    Filed: February 2, 2006
    Date of Patent: October 4, 2011
    Assignee: Panasonic Corporation
    Inventor: Wataru Ikeda
  • Publication number: 20100328812
    Abstract: According to one embodiment, a magnetic disk device includes a receiver, a storage module, a determining module, and a prescanner. The receiver receives a command from a host device. The storage module stores, with respect to each of divided areas formed by dividing the recording area of a recording medium into a plurality of areas, pre-scan control information indicating at least one of the receiving time and the number of receiving times. The receiving time indicates a time at which a write command is received. The number of receiving times indicates the number of times the write command is received within a predetermined period after the power is turned on. The determining module determines the order in which pre-scan is performed on the divided areas based on at least one of the receiving time and the number of receiving times. The prescanner pre-scans the divided areas in the determined order.
    Type: Application
    Filed: June 24, 2010
    Publication date: December 30, 2010
    Applicant: Toshiba Storage Device Corporation
    Inventors: Masamitsu OHHASHI, Michihiko UMEDA
  • Patent number: 7835106
    Abstract: A method of controlling the position of a read/write head relative to a disk in a test apparatus is disclosed. The test apparatus has a positioner for positioning the head. The positioner has a sensor to measure the actual position achieved by the positioner. The method includes generating a sensor signal measuring the actual position achieved by the positioner; generating a position error signal of the head relative to the disk detected at the head; high pass filtering the head position error signal and low pass filtering the sensor signal so that there is substantially no overlap in frequency between them; and, deriving a low frequency head error signal from the head position error signal corresponding to any drift of the head.
    Type: Grant
    Filed: June 25, 2007
    Date of Patent: November 16, 2010
    Assignee: Xyratex Technology Limited
    Inventor: Michael Alan Miles
  • Patent number: 7768738
    Abstract: Embodiments of mitigating the effects of disturbances of a disk drive are disclosed. One method includes sensing a position error signal of a transducer coupled to a surface of the disk drive, wherein the position error signal aids in control of an actuator of the disk drive. A first disturbance signal is generated by sensing a disturbance of a first sensor attached to the disk drive, wherein the first disturbance signal aids in control of the actuator. A second disturbance signal is generated by sensing a disturbance of a second sensor attached to the disk drive, wherein the second disturbance signal aids in control of the actuator. Effects of the disturbances on the position error signal are reduced by adaptively adjusting a gain of the first disturbance signal and a gain of the second disturbance signal.
    Type: Grant
    Filed: November 13, 2007
    Date of Patent: August 3, 2010
    Assignee: Sensor Platforms, Inc.
    Inventors: Daniel Yves Abramovitch, George Hsu
  • Patent number: 7760461
    Abstract: A disk drive is disclosed including a disk having a plurality of servo tracks. The servo tracks are banded together to form a plurality of servo track bands, and each servo sector comprises a fine track address that identifies one of the servo tracks. The disk drive further comprises a head attached to a distal end of an actuator arm operable to generate a read signal by reading the disk, and a mechanical position sensor operable to detect a coarse position of the actuator arm. The coarse position is processed to identify one of the servo track bands, and the read signal is processed to detect one of the fine track addresses, wherein the detected fine track address identifies a servo track within the identified servo track band. The identified servo track band is combined with the detected fine track address to generate a servo track address.
    Type: Grant
    Filed: November 24, 2008
    Date of Patent: July 20, 2010
    Assignee: Western Digital Technologies, Inc.
    Inventor: George J. Bennett
  • Patent number: 7701661
    Abstract: A disk drive is disclosed including a disk having a plurality of servo tracks. The servo tracks are banded together to form a plurality of servo track bands, and each servo sector comprises a fine track address that identifies one of the servo tracks. The disk drive further comprises a head attached to a distal end of an actuator arm operable to generate a read signal by reading the disk, and a mechanical position sensor operable to detect a coarse position of the actuator arm. The coarse position is processed to identify one of the servo track bands, and the read signal is processed to detect one of the fine track addresses, wherein the detected fine track address identifies a servo track within the identified servo track band. The identified servo track band is combined with the detected fine track address to generate a servo track address.
    Type: Grant
    Filed: November 24, 2008
    Date of Patent: April 20, 2010
    Assignee: Western Digital Technologies, Inc.
    Inventor: George J. Bennett
  • Patent number: 7697234
    Abstract: A rotation disturbance compensation control unit applies a compensation signal to a positioning control unit so as to cancel out rotation disturbance vibration components detected by using acceleration velocity sensors. At predetermined timing, a position error detection unit detects respective position errors of the case in which the rotation disturbance compensation control unit is turned on and the case in which it is turned off. A compensation control switching unit switches the rotation disturbance compensation control unit to be on if the position error of the case in which the compensation control of rotation disturbance is turned on is small and switches the compensation control switching unit to be off if the position error of the case in which the compensation control of rotation disturbance is turned off is small.
    Type: Grant
    Filed: February 20, 2008
    Date of Patent: April 13, 2010
    Assignee: Toshiba Storage Device Corporation
    Inventors: Yoshinari Higashino, Shigenori Yanagi
  • Publication number: 20100039727
    Abstract: A recording system for magnetic storage devices, including a beam column for generating a beam, a platform for moving a magnetic storage medium relative to the beam, and a signal generator for sequentially, or in a continuously alternating manner, deflecting the beam. In turn, the beam is directed according to displacement of dots on the extent of the magnetic storage medium such that dots of a plurality of dot groupings can be written to on the extent during a single pass of the beam column above the extent.
    Type: Application
    Filed: August 15, 2008
    Publication date: February 18, 2010
    Applicant: Seagate Technology LLC
    Inventors: David S. Kuo, Kim Y. Lee
  • Patent number: 7602577
    Abstract: A microactuator incorporated within an actuator assembly of a disk drive is used as a detection element for rapid off track events that may occur. Preferably, the microactuator employs one or more piezoelectric elements used for purposes of secondary actuation. Uncontrolled movement of the actuator across the disk results in the piezoelectric elements generating a voltage spike or signal that is analyzed to determine whether a rapid off track event has occurred. Rapid off track events are distinguished from other possible events, such as shock events. If a rapid off track event is detected, then remedial actions are taken to restore data integrity, to include executing restore commands such as rewriting selected data tracks. Dedicated piezoelectric elements may also be provided for detecting rapid off track events wherein these elements are not incorporated in the servo loop that controls positioning of the actuator.
    Type: Grant
    Filed: January 31, 2006
    Date of Patent: October 13, 2009
    Assignee: Seagate Technology LLC
    Inventors: Rickmer Kose, Erhard Schreck, Frank Obregon
  • Patent number: 7555947
    Abstract: An air pressure sensor capable of measuring air pressure highly accurately with a simple configuration is provided. The sensor includes: a sealed case with a sealed space formed therein; a first thin plate member which constitutes at least a part of the wall of the sealed case and deforms to allow the capacity of the sealed space to vary corresponding to changes in the outside air pressure; a first PZT which contacts the first thin plate member to thereby detect the natural frequency thereof; and a second thin plate member which has the same vibration characteristics as those of the first thin plate member and is provided outside the sealed case while contacting it; and a second PZT which has the same temperature characteristics as those of the first PZT and contacts the second thin plate member to thereby detect the natural frequency thereof.
    Type: Grant
    Filed: September 14, 2007
    Date of Patent: July 7, 2009
    Assignee: SAE Magnetics (H.K.) Ltd.
    Inventor: Tamon Kasajima
  • Patent number: 7529057
    Abstract: A control system including a filter module generates a filtered disturbance signal based on a disturbance signal and a transfer function of the filter module. A set point adjustment module generates an adjusted set point signal based on a set point signal and the filtered disturbance signal. A servo control module generates an error signal based on the adjusted set point signal and a position feedback signal. A filter adjustment module generates a filter adjustment signal based on the disturbance signal and the error signal. The filter adjustment signal adjusts the transfer function.
    Type: Grant
    Filed: September 8, 2008
    Date of Patent: May 5, 2009
    Assignee: Marvell International Ltd.
    Inventor: Pantas Sutardja
  • Patent number: 7495857
    Abstract: A disk drive is disclosed including a disk, an actuator arm, a head attached to a distal end of the actuator arm, a mechanical position sensor operable to generate a position signal representing a position of the head relative to the disk, and a voice coil motor for rotating the actuator arm about a pivot. The disk is rotated at a predetermined velocity, a control signal is generated in response to the position signal generated by the mechanical position sensor, and the control signal is applied to the voice coil motor in order to seek the head radially over the disk while writing a spiral track to the disk. The spiral track is then processed to maintain the head along a servo track while writing product servo sectors along the servo track.
    Type: Grant
    Filed: December 30, 2005
    Date of Patent: February 24, 2009
    Assignee: Western Digital Technologies, Inc.
    Inventor: George J. Bennett
  • Patent number: 7480116
    Abstract: A disk drive is disclosed including a disk having a plurality of servo tracks. The servo tracks are banded together to form a plurality of servo track bands, and each servo sector comprises a fine track address that identifies one of the servo tracks. The disk drive further comprises a head attached to a distal end of an actuator arm operable to generate a read signal by reading the disk, and a mechanical position sensor operable to detect a coarse position of the actuator arm. The coarse position is processed to identify one of the servo track bands, and the read signal is processed to detect one of the fine track addresses, wherein the detected fine track address identifies a servo track within the identified servo track band. The identified servo track band is combined with the detected fine track address to generate a servo track address.
    Type: Grant
    Filed: January 20, 2006
    Date of Patent: January 20, 2009
    Assignee: Western Digital Technologies, Inc.
    Inventor: George J. Bennett
  • Publication number: 20090002873
    Abstract: A sensing device for sensing installation position of a read head is assembled on the read head correspondingly to a scale and comprises at least three sensing elements and three signal generators. The three sensing elements are located on one end surface of the read head facing the scale to sense the distance between the read head and the scale. According to the different distance, the respective signal generators will send out different signals to inform the user if the read head is correctly installed, thus ensuring the precision of the installation, the sensing operation and movement of the read head.
    Type: Application
    Filed: June 27, 2007
    Publication date: January 1, 2009
    Inventor: Chih-Mao SHIAO
  • Patent number: 7468857
    Abstract: Disturbances to actuator control caused by external vibrations are corrected using feed-forward techniques that are selectively enabled or disabled based on signal values within a track follow loop. An increase in data integrity and reliability may be achieved by reducing off-track reads and writes caused by physical disturbances to disk drives during operation. Accelerometers detect external forces imparted on a disk and an acceleration feed-forward (AFF) signal is generated to compensate for disturbances to the location of a head caused by such external forces. Application of the AFF signal to an actuator may be based on whether signal values along the track follow loop exceed a certain threshold.
    Type: Grant
    Filed: February 9, 2007
    Date of Patent: December 23, 2008
    Assignee: Maxtor Corporation
    Inventors: Larry Hutsell, Dave Finamore, Farhad Navid
  • Patent number: 7450335
    Abstract: Methods and systems for reducing read/write head track misregistration are described. According to one embodiment, a first signal is received from a first capacitive sensor that faces a surface of a disk associated with a disk drive. A second signal is received from a second capacitive sensor that faces the surface of the disk. A determination is made as to whether the disk is being moved along its axis of rotation or whether the disk is tilting. Read/write head track misregistration is reduced based on the determination of whether the disk drive is being moved along an axis of rotation or whether the disk is tilting.
    Type: Grant
    Filed: August 9, 2006
    Date of Patent: November 11, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Toshiki Hirano, Tetsuo Semba, Matthew T. White
  • Publication number: 20080218897
    Abstract: Disclosed are a data storage apparatus, an assembling method thereof and an apparatus for generating a tracking position error signal capable of storing data using recording media formed with patterns for generating tracking position error signals to obviate errors that may be generated amidst storage of the data, wherein the patterns are formed for generating tracking position error signals on recording media before the recording media and storage are assembled to reduce the manufacturing cost and manufacturing process time.
    Type: Application
    Filed: March 4, 2008
    Publication date: September 11, 2008
    Inventors: Choong Woo Lee, Young Sik Kim, Jun Moon, Ji Young Jeong, Chung Choo Chung
  • Patent number: 7423833
    Abstract: A noise canceling system includes a signal generator module that generates a set point signal based on a desired position signal and a position feedback signal, a summation module that generates an output control signal based on the set point signal and a correction signal, and a filter module that generates the correction signal based on a disturbance signal and that minimizes a correlation between the disturbance signal and an error signal. The error signal represents a difference between the desired position signal and the position feedback signal.
    Type: Grant
    Filed: November 21, 2006
    Date of Patent: September 9, 2008
    Assignee: Marvell International Ltd.
    Inventor: Pantas Sutardja
  • Patent number: 7405896
    Abstract: A method and apparatus for detecting slider/disk fly-height modulation in a hard disk drive is provided. A slider is electrically isolating from an electrically grounded suspension. A signal line is coupled to the slider, the signal line for providing an alert signal when a modulation in fly-height between the slider and an electrically grounded disk of the hard disk drive occurs.
    Type: Grant
    Filed: April 26, 2006
    Date of Patent: July 29, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Toshiki Hirano, Ullal V. Nayak
  • Patent number: 7365932
    Abstract: A disk drive is disclosed comprising an actuator arm, a head attached to a distal end of the actuator arm, a voice coil motor for rotating the actuator arm about a pivot, and an optical sensor operable to generate a first position signal representing a position of the actuator arm with respect to the disk, wherein the first position signal is substantially unaffected by a vibration mode of the actuator arm. Servo sectors recorded on the disk are processed to generate a second position signal representing a position of the head with respect to the disk, wherein the second position signal comprises a significant component due to the vibration mode of the actuator arm. A control signal is applied to the voice coil motor in response to the first and second position signals.
    Type: Grant
    Filed: December 30, 2005
    Date of Patent: April 29, 2008
    Assignee: Western Digital Technologies, Inc.
    Inventor: George J. Bennett
  • Patent number: 7359138
    Abstract: In method of feedback control for active damping of slider air bearing vibrations in a hard disk drive slider, a slider is isolated from ground. A velocity signal is acquired from the slider. The velocity signal is filtered to acquire a vibration signal. The vibration signal is adjusted in amplitude to achieve an amplitude adjusted vibration signal. The amplitude adjusted vibration signal is applied to the slider to actively dampen vibrations in the slider.
    Type: Grant
    Filed: November 29, 2005
    Date of Patent: April 15, 2008
    Assignee: Hitachi Global Storage Technologies Nethelands, B.V.
    Inventors: Thomas R. Albrecht, Peter M. Baumgart, Bernhard E. Knigge
  • Publication number: 20080068742
    Abstract: An air pressure sensor capable of measuring air pressure highly accurately with a simple configuration is provided. The sensor includes: a sealed case with a sealed space formed therein; a first thin plate member which constitutes at least a part of the wall of the sealed case and deforms to allow the capacity of the sealed space to vary corresponding to changes in the outside air pressure; a first PZT which contacts the first thin plate member to thereby detect the natural frequency thereof; and a second thin plate member which has the same vibration characteristics as those of the first thin plate member and is provided outside the sealed case while contacting it; and a second PZT which has the same temperature characteristics as those of the first PZT and contacts the second thin plate member to thereby detect the natural frequency thereof.
    Type: Application
    Filed: September 14, 2007
    Publication date: March 20, 2008
    Applicant: SAE MAGNETICS (H.K.) LTD.
    Inventor: Tamon KASAJIMA
  • Patent number: 7321476
    Abstract: A method and system for determining contact potential voltages between a slider body and a hard disk of a hard disk drive. In embodiments of the present invention, at least one continuous negative direct current (DC) voltage is applied between a slider body and a hard disk of a hard disk drive. Then, at least one continuous positive direct current (DC) voltage is applied between the slider body and the hard disk. A contact potential voltage between the slider body and the hard disk is then determined in response to the applying of the direct current voltages.
    Type: Grant
    Filed: July 29, 2005
    Date of Patent: January 22, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Peter Michael Baumgart, Bernhard E. Knigge, Charles Mathew Mate
  • Publication number: 20080002281
    Abstract: An information recording apparatus comprises a recording medium, a swing arm driven by an actuation unit, the swing arm swinging over a surface of the recording medium in response to driving by the actuation unit, a recording head carried by the swing arm and scanning over the surface of said recording medium with a swinging motion of the swing arm by the actuation unit, the recording head recording information to the recording medium, a head retracting mechanism retracting the recording head out of the recording medium in an unload state where no recording is to be made on the recording medium, an optical injection unit injecting a light into the recording head, the recording head including an optical irradiation part irradiating the light injected to the recording head upon the recording medium when recording information to the recording medium, wherein the optical injection unit is integrated with the head retracting mechanism to form a unitary optical-injection and head-retraction mechanism.
    Type: Application
    Filed: November 14, 2006
    Publication date: January 3, 2008
    Applicant: FUJITSU LIMITED
    Inventor: Shinya Hasegawa
  • Patent number: 7277252
    Abstract: In a method of feedback control for active damping of slider air bearing vibrations in a hard disk drive slider, a slider is isolated from ground. A slider velocity signal is filtered to acquire a vibration signal. The vibration signal is adjusted in amplitude to achieve an amplitude adjusted vibration signal. The amplitude adjusted vibration signal is applied to the slider to actively dampen air bearing vibrations in the slider.
    Type: Grant
    Filed: November 29, 2005
    Date of Patent: October 2, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Thomas R. Albrecht, Peter M. Baumgart, Bernhard E. Knigge
  • Patent number: 7265931
    Abstract: Track mis-registration (TMR) correction is conditionally made in a hard disk drive using servo data in a closed loop servo control scheme, along with one or more alternative sensing schemes when an external shock or vibration occurs. The alternative sensing schemes include measurement of spindle motor speed using a frequency of servo markers read from a rotating disk, voice control motor (VCM) back emf, spindle motor speed back emf, and accelerometer readings. The predicted TMR resulting from the signal generated by the alternative sensing scheme(s) is simulated based upon a model of the disk drive system, and corrections are applied only if the expected TMR due to the disturbances is large enough that application of the corrections using the alternative sensing scheme would be likely to reduce the overall TMR.
    Type: Grant
    Filed: June 4, 2004
    Date of Patent: September 4, 2007
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Richard M. Ehrlich
  • Patent number: 7256586
    Abstract: The method and a device to measure the repeatable and non-repeatable runouts of a rotating component of a spindle motor with the aid of at least one probe measuring changes in the distance between the probe and the rotating component depending on the angle of rotation. The probe records a first test signal in a first test cycle from which a signal defining the RRO is determined and stored. In a second test cycle, a command signal proportional to the amplitude and phase of the RRO signal is generated and fed to an electromechanical actuator supporting the probe. Depending on the command signal derived from the first test signal, the actuator changes the distance between the probe and the outer perimeter of the rotating component, thus compensating the runout defined by the RRO signal, while the probe records a second test signal defining the NRRO.
    Type: Grant
    Filed: April 3, 2003
    Date of Patent: August 14, 2007
    Assignee: Minebea Co. Ltd
    Inventor: Guido Schmid
  • Patent number: 7221528
    Abstract: Magnetic alignment marks are recorded on a recording surface of a magnetic hard disk to mark the location where the disk is abutted against the hub of the spindle of a multiple-disk servo-writer. The alignment marks for each recording surface may be different so as to distinguish between top and bottom disk surfaces so that when the discs are assembled onto the spindle of a disk drive they may be assembled with the proper orientation, i.e., the top surface is mounted “up.” The marks may be large, low frequency patterns that are both written and detected by non contact means other than the servo-track writer's or the disk drive's heads.
    Type: Grant
    Filed: March 30, 2005
    Date of Patent: May 22, 2007
    Assignee: Seagate Technology LLC
    Inventors: David S. Kuo, Jason Pressesky, Dan Nguyen
  • Patent number: 7215500
    Abstract: In a feedback control mechanism for active damping of slider air bearing vibrations in a hard disk drive slider, an assembly is used to acquire a velocity signal from the slider. A filter, electrically coupled with the assembly, is used to filter a velocity signal to achieve a vibration signal. A phase-shifter, electrically coupled with the filter, shifts the phase of the vibration signal to achieve a phase-shifted vibration signal. An amplifier, electrically coupled with the phase-shifter, adjusts the amplitude of the phase-shifted vibration signal to achieve an amplitude adjusted vibration signal. An electrical coupler couples the amplitude adjusted vibration signal with the slider for actively damping air bearing vibrations in the slider.
    Type: Grant
    Filed: November 29, 2005
    Date of Patent: May 8, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Thomas R. Albrecht, Peter M. Baumgart, Bernhard E. Knigge
  • Patent number: RE40975
    Abstract: A head suspension assembly including a load beam having a rigid region, a mounting region on a proximal end of the load beam, and a flexure on a distal end of the load beam. The flexure has a read/write head attachment region for supporting a read/write head on the distal end of the load beam. Deformation of the head suspension assembly displaces the head attachment region. A strain transducer circuit that acts as a strain gauge is mounted on the head suspension assembly. The resistance of the transducer circuit varies with strain in the circuit, which, in turn, varies with displacement of the read/write head. The magnitude of resistance change of the transducer circuit indicates the magnitude of head off-neutral motion.
    Type: Grant
    Filed: June 9, 2006
    Date of Patent: November 17, 2009
    Assignee: Hutchinson Technology Incorporated
    Inventors: Robert B. Evans, Todd A. Krinke