Patents by Inventor Linden J. Crawforth

Linden J. Crawforth has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7703193
    Abstract: The lapping of a slider is controlled based on an amplitude of a readback signal which is produced from an externally applied magnetic field. A lapping plate is used to lap a slider which includes at least one magnetic head having a read sensor. During the lapping, a coil produces a magnetic field around the slider and processing circuitry monitors both a readback signal amplitude and a resistance of the read sensor. The lapping of the slider is terminated based on the monitoring both the readback signal amplitude and the resistance. Preferably, the lapping of the slider is terminated when the resistance is within a predetermined resistance range and the readback signal amplitude is above a predetermined minimum amplitude threshold or reaches its peak value. Asymmetry can also be measured in the described system, where the lapping process is terminated based on asymmetry as well as resistance and amplitude measurements.
    Type: Grant
    Filed: July 27, 2007
    Date of Patent: April 27, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Jacey Robert Beaucage, Linden J. Crawforth, Xiao Z. Wu
  • Patent number: 7386935
    Abstract: The lapping of a slider is controlled based on an amplitude of a readback signal which is produced from an externally applied magnetic field. A lapping plate is used to lap a slider which includes at least one magnetic head having a read sensor. During the lapping, a coil produces a magnetic field around the slider and processing circuitry monitors both a readback signal amplitude and a resistance of the read sensor. The lapping of the slider is terminated based on the monitoring both the readback signal amplitude and the resistance. Preferably, the lapping of the slider is terminated when the resistance is within a predetermined resistance range and the readback signal amplitude is above a predetermined minimum amplitude threshold or reaches its peak value. Asymmetry can also be measured in the described system, where the lapping process is terminated based on asymmetry as well as resistance and amplitude measurements.
    Type: Grant
    Filed: July 27, 2007
    Date of Patent: June 17, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Jacey Robert Beaucage, Linden J. Crawforth, Xiao Z. Wu
  • Patent number: 7260887
    Abstract: The lapping of a slider is controlled based on an amplitude of a readback signal which is produced from an externally applied magnetic field. A lapping plate is used to lap a slider which includes at least one magnetic head having a read sensor. During the lapping, a coil produces a magnetic field around the slider and processing circuitry monitors both a readback signal amplitude and a resistance of the read sensor. The lapping of the slider is terminated based on the monitoring both the readback signal amplitude and the resistance. Preferably, the lapping of the slider is terminated when the resistance is within a predetermined resistance range and the readback signal amplitude is above a predetermined minimum amplitude threshold or reaches its peak value. Asymmetry can also be measured in the described system, where the lapping process is terminated based on asymmetry as well as resistance and amplitude measurements.
    Type: Grant
    Filed: February 27, 2004
    Date of Patent: August 28, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Jacey Robert Beaucage, Linden J. Crawforth, Xiao Z. Wu
  • Patent number: 6786803
    Abstract: An onboard electronic lapping guide for lapping a magneto-resistive head having a magneto-resistive sensor element disposed for electrical communication with a pair of sensor electrical leads. The lapping guide includes an electronic lapping guide resistive element disposed for electrical communication with the sensor electrical leads. The resistive element has a predetermined height in a lapping direction and is adapted to produce an electrical resistance in the presence of a lapping current that increases as said resistive element height is reduced during lapping. A lapping method and a method of forming the onboard electronic lapping guide are also disclosed.
    Type: Grant
    Filed: November 19, 2002
    Date of Patent: September 7, 2004
    Assignee: International Business Machines Corporation
    Inventors: Linden J. Crawforth, Douglas J. Werner, Benjamin L. Wang, Timothy J. Minvielle
  • Publication number: 20040097173
    Abstract: An onboard electronic lapping guide for lapping a magneto-resistive head having a magneto-resistive sensor element disposed for electrical communication with a pair of sensor electrical leads. The lapping guide includes an electronic lapping guide resistive element disposed for electrical communication with the sensor electrical leads. The resistive element has a predetermined height in a lapping direction and is adapted to produce an electrical resistance in the presence of a lapping current that increases as said resistive element height is reduced during lapping. A lapping method and a method of forming the onboard electronic lapping guide are also disclosed.
    Type: Application
    Filed: November 19, 2002
    Publication date: May 20, 2004
    Applicant: International Business Machines Corporation
    Inventors: Linden J. Crawforth, Douglas J. Werner, Benjamin L. Wang, Timothy J. Minvielle
  • Patent number: 6556380
    Abstract: A trapezoidal shaped silicon slider is described in the present invention. The slider has a first parallel surface larger than a second parallel surface, thereby generating a built-in positive pitch with respect to a recording medium when the slider is incorporated into a hard disk drive. The slider further includes round edges at the first parallel surface, longitudinal holes within its body, non-planar slanted side surfaces, and a rounded leading edge. The silicon, trapezoidal slider is fabricated using a deep reactive ion etching (DRIE) technique.
    Type: Grant
    Filed: April 10, 2001
    Date of Patent: April 29, 2003
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Richard Bunch, Linden J. Crawforth, Anthony A. Razouk, Timothy C. Reiley
  • Publication number: 20020145827
    Abstract: A trapezoidal shaped silicon slider is described in the present invention. The slider has a first parallel surface larger than a second parallel surface, thereby generating a built-in positive pitch with respect to a recording medium when the slider is incorporated into a hard disk drive. The slider further includes round edges at the first parallel surface, longitudinal holes within its body, non-planar slanted side surfaces, and a rounded leading edge. The silicon, trapezoidal slider is fabricated using a deep reactive ion etching (DRIE) technique.
    Type: Application
    Filed: April 10, 2001
    Publication date: October 10, 2002
    Inventors: Richard Bunch, Linden J. Crawforth, Anthony A. Razouk, Timothy C. Reiley
  • Patent number: 5384675
    Abstract: A magnetic recording disk drive has a startup routine that frees the recording head carriers and moves them to a parking location, such as load/unload ramp or a disk landing zone, if they are stuck to the disks when the drive motor is attempted to be started. If the drive motor does not achieve its operating speed at normal startup of the disk drive, thus indicating that static friction or other "stiction" forces are adhering the carriers to the disks, a series of alternating current pulses is applied to the actuator to dither the carriers at an initial frequency that is generally equal to or above the resonant frequency of the actuator system with stuck carriers. The frequency and amplitude of the pulses is swept downward from the initial frequency and amplitude and repeated until the drive motor rotates at its operating speed.
    Type: Grant
    Filed: September 8, 1993
    Date of Patent: January 24, 1995
    Assignee: International Business Machines Corporation
    Inventors: Linden J. Crawforth, John S. Foster, Jaquelin K. Spong