Patents by Inventor Lawrence M. Bryant
Lawrence M. Bryant has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8743504Abstract: A disk drive is disclosed comprising a first head actuated over a first disk surface and a second head actuated over a second disk surface. A first servo sector of the first disk surface is read to generate a read signal which is processed to generate a first phase error. A first clock is generated at a frequency proximate a servo data rate of the first data sector. Read signal samples are synchronized in response to the first phase error and the first clock to generate synchronous samples, and servo data in the first servo sector is detected in response to the synchronous samples. The read signal is processed to generate a second phase error, a second clock is generated in response to the second phase error, and a spiral servo track is written to the second disk surface using the second clock.Type: GrantFiled: July 25, 2012Date of Patent: June 3, 2014Assignee: Western Digital Technologies, Inc.Inventors: Lawrence M. Bryant, Yun Hong, Charles A. Park
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Patent number: 7688539Abstract: A disk drive is disclosed comprising a disk, and a head actuated over the disk. The head is positioned at a radial location over the disk, and a servo burst is written at the current radial location. The servo burst is read to generate a read signal, and the read signal is processed to generate a position error signal (PES). The head is moved radially in response to the PES, and the process is repeated multiple times to form a spiral track spanning at least one revolution of the disk.Type: GrantFiled: May 14, 2008Date of Patent: March 30, 2010Assignee: Western Digital Technologies, inc.Inventors: Lawrence M. Bryant, Yakov M. Lifchits, Siri S. Weerasooriya
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Patent number: 7602575Abstract: A disk drive is disclosed comprising control circuitry for self servo writing a disk. An estimated reader/writer offset is initialized, servo bursts in a first servo track are read, the head is moved radially using the estimated reader/writer offset, and propagated servo bursts are written to a target servo track. The propagated servo bursts are read from the target servo track to generate a read signal, the read signal is processed to generate a burst crossing signal (BCS), and the estimated reader/writer offset is adjusted in response to the BCS.Type: GrantFiled: May 14, 2008Date of Patent: October 13, 2009Assignee: Western Digital Technologies, Inc.Inventors: Yakov M. Lifchits, Lawrence M. Bryant, Siri S. Weerasooriya, Wing Ying
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Patent number: 7298678Abstract: A rotating recording device, such as an electron beam recorder, is provided with a dual encoder arrangement. A first encoder is employed as a spindle motor controller and located at a first end of a spindle. A second encoder is mounted at a turntable adjacent to a recording surface and used as a position, velocity or clock source for recording the pattern on the substrate. Eccentricity of the mounting of the second encoder is measured against the more accurately mounted spindle control encoder and compensated by a digital clock generating system using a digital phase locked loop.Type: GrantFiled: August 19, 2004Date of Patent: November 20, 2007Assignee: Seagate Technology LLCInventors: Lawrence M. Bryant, Sundeep Chauhan, David Shiao-Min Kuo
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Patent number: 7199959Abstract: A servo writing system for writing servo sectors onto a disk includes a direct digital synthesizer (DDS) that forms a phase and frequency adjustable continuous wave signal based upon a reference digital clock signal. A PLL coupled to the DDS measures repeatable timing errors (RTEs) associated with the continuous wave signal and generates an output clock signal that is used to clock the writing of servo sectors onto the disk. A digital control system is coupled to the DDS and the PLL, which calculates repeatable error compensation adjustment values based on the RTEs measured using the PLL. The compensation adjustment values may be applied to the DDS such that the DDS compensates for the RTEs and such that the output clock signal used to clock the writing of the servo sectors onto the disk includes minimal RTEs.Type: GrantFiled: December 13, 2004Date of Patent: April 3, 2007Assignee: Western Digital Technologies, Inc.Inventor: Lawrence M. Bryant
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Patent number: 6785075Abstract: A disc drive with an information portion previously written on a rotatable disc surface, a servo write clock generator phase lock loop circuit controlling timing for writing a reference mark to the rotatable disc surface in substantial time alignment and phase and frequency coherent with the information portion previously written to the rotatable disc surface, a servo write clock generator phase lock loop circuit controlling timing for writing the reference mark, a pulse detector circuit for creating logic level signals from the reference mark, a pattern generator for generating reference mark write signals from the logic level signals, a memory buffer for storing radial position correction tables and values for writing the reference mark, and a self-servo control and sequencing circuit synchronizing timing signals for writing the reference mark to rotatable disc surface of disc drive.Type: GrantFiled: July 26, 2001Date of Patent: August 31, 2004Assignee: Seagate Technology LLCInventors: Lawrence M. Bryant, Gabor Szïta, Alan A. Fennema, Karl A. Belser, Robert D. Murphy
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Patent number: 6414807Abstract: A disk drive system is described for forming and reading precise optically detectable patterns on rotating members of a disk and spindle assembly used in data storage system. In particular the invention describes a magnetic disk drive employing a laser system to form and sense optical clock patterns placed on the rotating members of the disk drive. These optically detectable patterns are used to create an accurate clock track. The clock may be used to create multiple accurate magnetic patterns on one or more disks attached to a disk and spindle assembly in a magnetic data storage system. By successively changing the radius at which the magnetic patterns are created it is then possible to create multiple magnetic patterns at successive radii with all such magnetic patterns having a precise geometric relationship to each other. Alternatively, the accurate clock pattern may stand alone as an encoder.Type: GrantFiled: July 22, 1998Date of Patent: July 2, 2002Assignee: Seagate Technology LLCInventors: Charles A. Bates, Lawrence M. Bryant, David S. Kuo, Eric G. Rawson
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Publication number: 20020048107Abstract: A disc drive with an information portion previously written on a rotatable disc surface, a servo write clock generator phase lock loop circuit controlling timing for writing a reference mark to the rotatable disc surface in substantial time alignment and phase and frequency coherent with the information portion previously written to the rotatable disc surface, a servo write clock generator phase lock loop circuit controlling timing for writing the reference mark, a pulse detector circuit for creating logic level signals from the reference mark, a pattern generator for generating reference mark write signals from the logic level signals, a memory buffer for storing radial position correction tables and values for writing the reference mark, and a self-servo control and sequencing circuit synchronizing timing signals for writing the reference mark to rotatable disc surface of disc drive.Type: ApplicationFiled: July 26, 2001Publication date: April 25, 2002Inventors: Lawrence M. Bryant, Gabor Szita, Alan A. Fennema, Karl A. Belser, Robert D. Murphy
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Patent number: 6356401Abstract: The present invention is used to form precise, optically detectable patterns on rotating members of a disk and spindle assembly of a disk drive used in data storage system. In particular, the invention employs an optical source to form optically detectable patterns on the rotating members of the disk drive. These optically detectable patterns are used to create an accurate clock track. The clock track may be used to create multiple accurate magnetic patterns on one or more disks attached to a disk and spindle assembly in a magnetic data storage system. By successively changing the radius at which the magnetic patterns are created it is then possible to create multiple magnetic patterns at successive radii with all such magnetic patterns having a precise geometric relationship to each other. Alternatively, the accurate clock pattern may stand alone as an encoder.Type: GrantFiled: July 22, 1998Date of Patent: March 12, 2002Assignee: Seagate Technology LLCInventors: Charles A. Bates, Lawrence M. Bryant, David S. Kuo, Eric G. Rawson
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Patent number: 6349079Abstract: A system and method are provided for processing signals in a magneto-optical computer memory device to detect mispositioning of a head with respect to a track centerline. A light beam is scanned over a first and a second set of radially offset optically-detectable position marks formed in the rotating medium surface. A detector receives the reflected light beam and responsively generates a position signal having a plurality of pulses corresponding to the position marks. The position signal is then passed through a differentiator circuit. The differentiated position signal may then be applied to low pass filter and resonator circuits, and is subsequently conveyed to a finite time integrator for rectification and detection of the areas of the pulses associated with the first and second set of position marks. Mispositioning of the head is detected by comparing the pulse areas of the first and second set of position marks.Type: GrantFiled: October 8, 1999Date of Patent: February 19, 2002Assignee: Seagate Technology LLCInventors: Karl A. Belser, Lawrence M. Bryant, John H. Richards
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Publication number: 20010012167Abstract: A disk drive system is described for forming and reading precise optically detectable patterns on rotating members of a disk and spindle assembly used in data storage system. In particular the invention describes a magnetic disk drive employing a laser system to form and sense optical clock patterns placed on the rotating members of the disk drive. These optically detectable patterns are used to create an accurate clock track. The clock may be used to create multiple accurate magnetic patterns on one or more disks attached to a disk and spindle assembly in a magnetic data storage system. By successively changing the radius at which the magnetic patterns are created it is then possible to create multiple magnetic patterns at successive radii with all such magnetic patterns having a precise geometric relationship to each other. Alternatively, the accurate clock pattern may stand alone as an encoder.Type: ApplicationFiled: July 22, 1998Publication date: August 9, 2001Inventors: CHARLES A BATES, LAWRENCE M BRYANT, DAVID S KUO, ERIC G RAWSON
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Frequency, phase and amplitude control apparatus and method for acousto-optic deflector optimization
Patent number: 5255257Abstract: An electronic circuit is described which will allow an acoustoptic deflector to be used in multi-frequency mode at high power levels with a minimum amount of intermodulation between each frequency. Reduction of interference between multiple separate signal frequencies is achieved by precise control of the individual phasing of each separate frequency relative to a common reference frequency. The relative phase of each frequency is also controlled so that a low maximum power is achieved for the combined signal that is presented to the acousto-optic deflector without decreasing the overall average power of the multiple signal frequencies. The present invention is useful in systems such as optical data storage on tape or disk, optical printing and imaging, and acousto-optic signal or information processing.Type: GrantFiled: March 4, 1992Date of Patent: October 19, 1993Assignees: Lasertape Systems, Inc., Lawrence M. Bryant, James W. DicksonInventors: Lawrence M. Bryant, James W. Dickson, David R. Rodal -
Patent number: 4600868Abstract: An open loop controller for the stepper motor of a disk drive actuator is programmed to supply pulse width modulated drive voltages for energizing and de-energizing successive phases of the stepper motor at controlled rates during the initial and final phases of each actuator seek, thereby controlling the acceleration and deceleration profiles of the actuator to reduce its mid-frequency resonance, settling time and position hysterysis.Type: GrantFiled: May 9, 1983Date of Patent: July 15, 1986Inventor: Lawrence M. Bryant