Patents Examined by Dan I Davidson
  • Patent number: 6587408
    Abstract: Micron-scale, self-contained, ultra-high density and ultra-high speed storage devices include a read/write head and a surface, containing bit-storage domains, that acts as the storage medium. The read/write element of the memory device may consist of a single or multiple heads. The read/write head may be mounted on microelectromechanical structures driven at mechanical resonance. Addressing of individual bits is accomplished by positioning of the head element in close proximity to bit domains situated on the storage medium.
    Type: Grant
    Filed: September 30, 1999
    Date of Patent: July 1, 2003
    Assignee: Massachusetts Institute of Technology
    Inventors: Joseph M. Jacobson, Brian N. Hubert, Brent Ridley
  • Patent number: 6587135
    Abstract: The present invention provides a card recording apparatus capable of printing in high speed as well as reducing overall dimensions of the apparatus. After a card is transported to an information recording section 200 in a lateral (short length) direction of the card, an information signal is recorded on the card thereby. Then, the card is transported to a second heating section 300. An ink image formed on an intermediate recording medium 7 by a first heating section 500 is re-transferred to the card by the second heating section 300. A warp developed on the card by the second heating section 300 is corrected by a card warp correcting section 400.
    Type: Grant
    Filed: October 15, 1999
    Date of Patent: July 1, 2003
    Assignee: JVC Victor Company of Japan, Ltd.
    Inventors: Yoshitaka Suzuki, Satoshi Yonemitsu
  • Patent number: 6587290
    Abstract: A master information carrier comprises a substrate whose surface has an embossed pattern corresponding to an information signal. At least a surface of the protruding portion of the embossed pattern is made of a ferromagnetic material. A method for writing an information signal into a sheet or disk magnetic record medium with a ferromagnetic thin film or coating is performed by putting the surface of the magnetic record medium into contact with the master information carrier so as to write a magnetized pattern corresponding to the embossed pattern of the master information carrier into the magnetic record medium.
    Type: Grant
    Filed: February 26, 2002
    Date of Patent: July 1, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Tatsuaki Ishida, Ryuji Sugita, Kiyokazu Tohma, Kazunari Yoshimoto, Keizou Miyata
  • Patent number: 6587294
    Abstract: Method and apparatus to correct an error of read-out data from a data storage medium, particularly a bit shift error, is described. The correction apparatus includes a gray bit detection circuit which flags bits with a phase shift exceeding a threshold and determines whether the previous or next bit cell has a smaller phase error. An RLL error detection circuit and a table containing valid bit combinations may be used in combination with the gray bit detector to correct errors on-the-fly without degrading performance. An advantage of the invention is that it allows correction of errors without regard to conventional ECC and its maximum number of errors.
    Type: Grant
    Filed: October 5, 1999
    Date of Patent: July 1, 2003
    Assignee: International Business Machines Corporation
    Inventors: Teruhiko Ushio, Toshio Kanai
  • Patent number: 6580572
    Abstract: A combination glide test/burnishing head can be utilized in a glide test/burnishing system. The combination glide test/burnishing head includes two piezo-electric elements, which can be utilized in a passive mode as sensors for detecting contacts between the glide test/burnishing head and asperities on the surface of a magnetic recording disc. Contact between the glide test/burnishing head and disc asperities results in generation of a defect detection signal, which can be utilized by associated test logic to define the location of the detected asperities on the disc surface. The piezo-electric elements of the glide test/burnishing head can also be utilized in an active mode to cause yaw variation in the flight attitude of the glide test/burnishing head, in turn causing a burnishing pad on the glide test/burnishing head to be moved radially into contact with a detected disc asperity.
    Type: Grant
    Filed: December 14, 2000
    Date of Patent: June 17, 2003
    Assignee: Seagate Technology LLC
    Inventors: Wei Hsin Yao, Ramesh Sundaram, David Shiao-Min Kuo
  • Patent number: 6580578
    Abstract: A method and apparatus in a data storage system for accessing a tape storage media, wherein the tape storage media has a first side and a second side for storing data. The tape storage media is received at a reel. The reel is rotatable in a first direction and in a second direction, and the reel is positioned proximate to a head used to access the tape storage media as the tape storage media is wound onto the reel. The reel is selectively rotated in the first direction and the second direction to selectively present the first side and the second side for access by the head.
    Type: Grant
    Filed: January 12, 2000
    Date of Patent: June 17, 2003
    Assignee: Storage Technology Corporation
    Inventors: Matthew Tucker, Bryan D. Penner
  • Patent number: 6577461
    Abstract: A magnetic disk drive having an active filter supplied with a read waveform of a magnetic disk, an A/D converter supplied with an output of the active filter, a waveform equalizer supplied with an output of the A/D converter. An adaptive learning unit for adaptively learning a boost characteristic of the active filter on the basis of an input and an output of the waveform equalizer so that error in the waveform equalizer is minimized. An abnormal learning detection unit for detecting an abnormal operation in adaptive learning of the boost characteristic just after learning of a sector and a boost characteristic resetter for resetting the boost characteristic before adaptive learning to an initial value before adaptive learning of a next sector when abnormality occurs in adaptive learning of the adaptive learning unit.
    Type: Grant
    Filed: June 12, 2002
    Date of Patent: June 10, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Naoki Satoh, Seiichi Mita
  • Patent number: 6567227
    Abstract: A master information carrier comprises a substrate whose surface has an embossed pattern corresponding to an information signal. At least a surface of the protruding portion of the embossed pattern is made of a ferromagnetic material. A method for writing an information signal into a sheet or disk magnetic record medium with a ferromagnetic thin film or coating is performed by putting the surface of the magnetic record medium into contact with the master information carrier so as to write a magnetized pattern corresponding to the embossed pattern of the master information carrier into the magnetic record medium.
    Type: Grant
    Filed: March 26, 2002
    Date of Patent: May 20, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Tatsuaki Ishida, Ryuji Sugita, Kiyokazu Tohma, Kazunari Yoshimoto, Keizou Miyata, Hiroshi Ryonai
  • Patent number: 6556367
    Abstract: High-accuracy position signals are obtained by correcting nonlinear position sensitivities of two phase signals demodulated from two-phase servo information, into linear ones. A position sensitivity adjusting unit detects the signal level at the intersection of position signals N and Q having different phases by a predetermined track pitch which are demodulated from read signals of two-phase servo information buried and recorded in a disk medium and makes an adjustment of the gain of an AGC amplifier so that the intersection signal level coincides with a predetermined level. A sensitivity correcting unit corrects into linear position sensitivities the nonlinear position sensitivities approximated by sine functions or cosine functions relative to the actual track position X of the two position signals N and Q output from the AGC amplifier.
    Type: Grant
    Filed: December 28, 2000
    Date of Patent: April 29, 2003
    Assignee: Fujitsu Limited
    Inventor: Eisaku Takahashi
  • Patent number: 6545832
    Abstract: A parameter value is set in a register. A signal is read based on the parameter value. When an error is recognized from an MSE value calculated by a Viterbi decoder, the parameter value is changed and the signal is reread. A new parameter value is calculated based on a change value by which the parameter value is changed and the MSE value. The new parameter value is stored in the register. Thus, an error rate can be converged as a result of the retry.
    Type: Grant
    Filed: October 12, 1999
    Date of Patent: April 8, 2003
    Assignees: Alps Electric Co., Ltd., Sony Corporation
    Inventors: Takayuki Sugawara, Takahiro Kawauchi, Kazuya Seta
  • Patent number: 6542324
    Abstract: A driving circuit for a voice coil motor (VCM) includes a full bridge output stage for driving the motor in a pulse width modulated (PWM) mode. A multiplexer having two inputs is coupled to respective output nodes of the full bridge output stage, with one of the output nodes providing a back electromotive force induced in the motor upon setting in a high impedance state the full bridge output stage and conducting at least one transistor connected to ground in the full bridge output stage after current through the motor has decayed to zero. A controller compares a voltage representing a desired speed of the motor with the back electromotive force, and generates a correction signal based upon the comparison.
    Type: Grant
    Filed: March 21, 2000
    Date of Patent: April 1, 2003
    Assignee: STMicroelectronics S.r.l.
    Inventors: Ezio Galbiati, Matteo Moioli
  • Patent number: 6538835
    Abstract: Apparatus and method for compensating for position signal distortion during a disc drive seek. A disc drive has first and second data recording surfaces on which tracks are defined, a moveable actuator which supports first and second magneto-resistive heads, and a servo circuit which applies current to an actuator motor to position the heads. During a seek in which the first head is moved from an initial track to a first destination track, upon loss of transduced servo data from the first data recording surface indicative of radial position of the head, the servo circuit switches from the first head to the second head and applies current to the actuator motor to move the second head to a known radial position with respect to the first destination track while transducing servo data from the second data recording surface. The servo circuit subsequently switches back to the first head to position the first head over the first destination track.
    Type: Grant
    Filed: November 4, 1999
    Date of Patent: March 25, 2003
    Assignee: Seagate Technology LLC
    Inventor: Matthew C. Burton
  • Patent number: 6538843
    Abstract: In a high-frequency impedance type magnetic head having high impedance and capable of efficiently detecting a change in impedance, an electrically conductive metal film is sandwiched between two soft magnetic films, and the two soft magnetic films form a portion of a magnetic path. The thickness of one soft magnetic film is smaller than the thickness of the other soft magnetic film. The electrically conductive metal thin film has a pair of electrodes at respective ends thereof, to which are connected an oscillator for applying a high frequency carrier signal to the electrodes and a high frequency amplifier having a demodulator circuit. Further, an electrically conductive metal film winding is provided, and a DC current is applied to the electrically conductive metal film winding at the time of reproduction, while on the other hand, a signal current is applied to the electrically conductive metal film winding at the time of recording.
    Type: Grant
    Filed: November 2, 2000
    Date of Patent: March 25, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Akio Kuroe, Sayuri Muramatsu, Hirotsugu Fusayasu, Akio Murata
  • Patent number: 6532125
    Abstract: The invention discloses novel apparatus/methodology for writing/erasing high-density data on a digital recording media. A preferred embodiment of the invention features a novel thermal near-field heater that may be employed in the apparatus, particularly for realizing the methodology in a substantially thermal near-field mode. The invention provides advantages of data storage densities greater than that of diffraction limited systems, for example, data storage densities of approximately greater than 100 Gbit/inch2, and writing speeds approximately greater than 100 MHz.
    Type: Grant
    Filed: September 30, 1999
    Date of Patent: March 11, 2003
    Assignee: International Business Machines Corporation
    Inventors: Hendrik F. Hamann, Yves Martin, Hemantha Kumar Wickramasinghe
  • Patent number: 6532121
    Abstract: A compression system stores meta-data in the compressed record to allow better access and manage merging data. Markers are added to the compression stream to indicate various things. Each compressed record has a marker to indicate the start of the compressed data. These markers have sector number as well as the relocation block numbers embedded in their data. A second marker is used to indicate free space. When compressed data is stored on the disk drive, free space is reserved so that future compression of the same, or modified, data has the ability to expand slightly without causing the data to be written to a different location. Also the compressed data can shrink and the remaining space can be filled in with this free space marker. A third type of marker is the format pattern marker. Compression algorithms generally compress the format pattern very tightly. However, the expectation is that the host will write useful data to the storage device.
    Type: Grant
    Filed: October 25, 1999
    Date of Patent: March 11, 2003
    Assignee: Hewlett-Packard Company
    Inventors: Robert A. Rust, Douglas L. Voigt
  • Patent number: 6525897
    Abstract: Apparatus using information about the extent of errors in sensed data for performing as a control function at least one of adjusting the position of a magnetic head to improve alignment relative to a track and selecting from two or more data signals a data signal having the least amount of errors is shown. The apparatus uses information about the extent of errors to perform a control function for reproducing the data stored in predetermined storage locations in a storage media. The apparatus positions a transducer for sensing from predetermined storage locations stored data containing at least one constraint. The transducer generates a first signal representative of the data containing at least one constraint stored in the sensed data and any errors introduced into the sensed data during the sensing.
    Type: Grant
    Filed: November 21, 2001
    Date of Patent: February 25, 2003
    Assignee: Acorn Technologies, Inc.
    Inventors: Alvin M. Despain, R. Stockton Gaines
  • Patent number: 6515957
    Abstract: Ferroelectric thin films can hold non-volatile memories with bit sizes down to 30 nm at room temperature. This invention provides a data storage system that preferably comprises an electrically conducting rotatable hard disk substrate having a ferroelectric storage layer that comprises storage cells which can be written and read along concentric recording tracks, a pivoted servo arm with a free end for movement across the recording tracks. The free end of the servo arm includes both a write head, consisting of an electrically conducting tip, and a read head, consisting of a field effect transistor (FET), held close to the disk surface. The FET has a gate electrode and is positioned on the servo arm with the gate electrode held close to the ferroelectric surface of the disk during read operations of the data storage system. Read and write operations can be performed with standard semiconductor technologies in combination with existing magnetic hard-disk servo-control architecture.
    Type: Grant
    Filed: October 6, 1999
    Date of Patent: February 4, 2003
    Assignee: International Business Machines Corporation
    Inventors: Dennis M. Newns, Jonathan Z. Sun
  • Patent number: 6515814
    Abstract: The present invention provides a magnetic signal reproducing device including heating means for locally heating a reproducing region of a magnetic recording medium, first reproducing means for reading magnetic information in the reproducing region in a first temperature state to obtain a first reproduced signal, second reproducing means for reading magnetic information in almost the same region as the reproducing region in a second temperature state which is different from the first temperature state to obtain a second reproduced signal, and correcting means for correcting the first reproduced signal based on the second reproduced signal to obtain an information reproducing signal representing information recorded in the reproducing region. According to this, even if a medium temperature in a non-heated region of the magnetic recording medium is shifted from a magnetization compensation point, a signal from the region is prevented from mixing into a reproducing signal.
    Type: Grant
    Filed: January 28, 2000
    Date of Patent: February 4, 2003
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Masaki Hamamoto, Junichi Sato, Yasushi Ogimoto, Kunio Kojima
  • Patent number: 6512648
    Abstract: A magnetic storage apparatus exploits the inherent characteristics of a magnetoresistive element to improve the performance of a magnetic head employing the element. Variations in element height or element thickness of the magnetoresistive element are considered in the selection of a sense current appropriate to the element size, by measuring the voltage between the terminals of the magnetoresistive head and controlling the sense current so that the output reference voltage approaches a predetermined value. In another embodiment, the sense current is controlled so that the voltage amplitude or a reference amplitude are set to a predetermined value. In both embodiments, a conversion table is preferably used to relate voltage amplitudes with sense currents, whereby an appropriate sense current is selected based upon the voltage amplitude.
    Type: Grant
    Filed: August 8, 2000
    Date of Patent: January 28, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Reijiro Tsuchiya, Mikio Suzuki
  • Patent number: 6504362
    Abstract: Side-reading of an abutted-junction magnetic transducer is measured by constructing at least one microtrack having a transition density. The transducer is moved relative to the microtrack to identify a plurality of positions of the transducer relative to the microtrack where the transducer provides a predetermined response. The side-reading distance of the transducer is identified from the plurality of positions. In one embodiment, a plurality of microtracks are constructed during different iterations, each having a different transition density, and the positions of the transducer are identified during each iteration relative to the respective microtrack. In another embodiment, the selected transition density has a fundamental frequency, and the position of the transducer is identified relative to the microtrack where the transducer provides the predetermined response at each of a plurality of harmonic frequencies of the fundamental frequency.
    Type: Grant
    Filed: July 11, 2001
    Date of Patent: January 7, 2003
    Assignee: Seagate Technology LLC
    Inventors: Douglas Saunders, Juan Fernandez-de-Castro, Erli Chen, Lujun Chen