Patents Issued in September 14, 2004
  • Patent number: 6791774
    Abstract: A contact magnetic transfer method forms a pattern of magnetized servo regions in the magnetic recording layer of a rigid perpendicular magnetic recording disk. A master disk or template has a rigid or flexible base with a first film of soft magnetic material on the base and a pattern of islands of soft magnetic material on and extending above the first film and recesses between the islands. The slave disk to be servo patterned is either DC magnetized in a first direction perpendicular to the plane of the recording layer or AC-erased. The slave disk is then placed with its outer layer in proximity to the islands of the master template and a magnetic field is applied in a perpendicular direction to magnetize the regions beneath the islands in the same direction as the applied field. In the regions of the recording layer beneath the recesses of the template the magnetization is reversed from that in the regions beneath the islands.
    Type: Grant
    Filed: May 12, 2003
    Date of Patent: September 14, 2004
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Thomas R. Albrecht, Zvonimir Z. Bandic
  • Patent number: 6791775
    Abstract: The present invention is a method and system to determine a quality of a head in a hard disk drive. The method comprises providing a disk having a at least one side with a plurality of tracks, writing on a predetermined track on the plurality of tracks and reading a profile of the predetermined track to provide a first profile value. The head is then moved to an adjacent track where it writes on the adjacent track. A profile of the predetermined track is then read to provide a second profile value. A quality of the head can then be determined based on the first and second values.
    Type: Grant
    Filed: October 15, 2001
    Date of Patent: September 14, 2004
    Assignee: Samsung Electronics, Co., Inc.
    Inventors: Zhaohui Li, Geng Wang, Keung Youn Cho
  • Patent number: 6791776
    Abstract: In order to generate a sampling clock having a higher accuracy, a synchronous signal generating circuit is provided with a phase error detector, detecting a phase error of a read out signal digitized on the basis of FDTS algorithm, and a VCO, controlling an oscillation frequency on the basis of a phase error detected by the phase error detector, to generate a synchronous signal by the VCO. On the basis of the synchronous signal generated by the synchronous signal generating circuit, an ADC digitizes the read out signal. The digitized read out signal is then converted to binary data by a detection circuit.
    Type: Grant
    Filed: February 28, 2001
    Date of Patent: September 14, 2004
    Assignees: Hitachi, Ltd., Hitachi Video and Information System, Inc.
    Inventors: Takatoshi Kato, Takushi Nishiya, Hideyuki Yamakawa, Takashi Nara, Nobuaki Nakai, Hiroshi Ide, Shintaro Suzumura, Terumi Takashi
  • Patent number: 6791777
    Abstract: A data discriminating unit includes a data discriminator and a sync signal discriminator. A data sync signal is detected for the bit string discriminated from the output of the sync signal discriminator, and the data is demodulated for the bit string discriminated from the output of the data discriminator, thereby optimizing the signal to a form suitable for discrimination and detection of the data sync signal and demodulation for data reproduction. As a result, the detection performance of the data sync signal can be improved while maintaining the data discrimination performance. A Viterbi decoder is used for discrimination by the data discriminator and the sync signal discriminator for the optimization thereby to optimize the number of states, the number of paths for state transition and the path memory length. A signal having no continuous inversions of the recording data is used as the data sync signal.
    Type: Grant
    Filed: February 16, 2001
    Date of Patent: September 14, 2004
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yoshiju Watanabe, Terumi Takashi
  • Patent number: 6791778
    Abstract: An apparatus, method and computer program product for a hard disk drive defect detection system. In one embodiment, a method of detecting defects on the surface of a disk having a plurality of tracks is recited. The method comprises reading, one or more times, the servo bits for a plurality of sectors and determining a burst measure for at least one sector, where the burst measure is a function of the burst signals for the sector. This method further comprises determining a reference value, where the reference value is a function of the burst signals of the plurality of sectors, and comparing the burst measure of at least one sector to the reference value to identify a potential defect. In one embodiment, a sector is mapped as defective where its burst measure differs from the reference value by at least 5 percent.
    Type: Grant
    Filed: September 13, 2001
    Date of Patent: September 14, 2004
    Assignee: Samsung Electronics Co., Inc.
    Inventors: Sang Hoon Chu, Jun Seok Shim, Seong Hwon Yu, Soo Il Choi
  • Patent number: 6791779
    Abstract: A disk drive having a connection-blocking device for use with a Serial Advanced Technology Attachment (SATA) power receptacle. The disk drive has a moveable head for writing and reading to and from a disk, a printed circuit board assembly (PCBA) for controlling operations in the disk drive, a Serial Advanced Technology Attachment (SATA) section attached to the PCBA having a SATA power receptacle and a SATA data receptacle, a legacy Integrated Drive Electronics (IDE) power receptacle attached to the PCBA, and a connection-blocking device. The legacy IDE power receptacle is electrically common with the SATA power receptacle. The connection-blocking device is attachable to either one of the SATA power receptacle or the legacy IDE power receptacle, respectively, to prevent redundant power connections within the disk drive.
    Type: Grant
    Filed: September 30, 2002
    Date of Patent: September 14, 2004
    Assignee: Western Digital Technologies, Inc.
    Inventors: Dalwinder Singh, Marc B. Goldstone
  • Patent number: 6791780
    Abstract: The present invention is a method and system to optimize a write channel in a hard disk drive. The method comprises providing a disk having a at least one side with a plurality of tracks, and selecting a target track from the plurality of tracks. Data is written at least once on a predetermined plurality of tracks adjacent to either side of the target track and on the target track. Data is also written a predetermined number of times on tracks immediately adjacent to the target track. Data written on the predetermined plurality of tracks adjacent to either side of the target track and on the target track is then read. The process then determines if a number of errors on the tracks is greater than a predetermined criteria, if so, a write current value of the write channel is decreased, otherwise the write current value is increased.
    Type: Grant
    Filed: October 15, 2001
    Date of Patent: September 14, 2004
    Assignee: Samsung Electronics Co., Inc.
    Inventors: Hae Jung Lee, Sang Lee, Keung Youn Cho, Ken Bovatsek
  • Patent number: 6791781
    Abstract: A method and apparatus for providing linear position (LPOS) estimations. If valid LPOS data may be detected from the tape, then a first method for LPOS estimation is performed using the Hall effect sensors. If valid LPOS data may not be detected from the tape, then an error recovery procedure (ERP) is invoked so that a second method for LPOS estimation is used to provide accurate LPOS information which is synchronized to a validly detected LPOS from tape within about 1 meter prior to the desired data record.
    Type: Grant
    Filed: July 17, 2001
    Date of Patent: September 14, 2004
    Assignee: International Business Machines Corporation
    Inventors: Nhan X. Bui, John Alexander Koski, Akimitsu Sasaki, Keisuke Tanaka, Kazuhiro Tsuruta
  • Patent number: 6791782
    Abstract: A method and an apparatus select the operational spindle rotation rate for a disk drive based on measured performance of the head-disk assembly. The position error values are measured and analyzed to generate a position error metric. Based on the value of the position error metric, an operational spindle rotation rate is selected for use when the head-disk assembly is combined with a controller to produce a disk drive.
    Type: Grant
    Filed: January 31, 2002
    Date of Patent: September 14, 2004
    Assignee: Western Digital Technologies, Inc.
    Inventors: Raffi Codilian, William D. Johns, Joseph M. Viglione
  • Patent number: 6791783
    Abstract: A magnetic head device including a slider, a resilient supporting member which supports the slider, and piezoelectric elements which are mounted on the resilient supporting member. The piezoelectric elements each include a piezoelectric layer and a pair of electrode layers, a first electrode layer and a second electrode layer. The surface of each second electrode layer and a stationary base end portion and a sliding portion are joined together through an electrically conductive adhesive resin, and both end portions of each piezoelectric element and the stationary base end portion and the sliding portion are joined together through a nonconductive adhesive resin.
    Type: Grant
    Filed: March 15, 2002
    Date of Patent: September 14, 2004
    Assignee: Alps Electric Co., Ltd.
    Inventor: Masayoshi Nakagawa
  • Patent number: 6791784
    Abstract: The diffraction-based monitoring techniques described herein can be used, for example, as quality assurance measure in manufacture of magnetic recording media with servo tracking. In one embodiment, the invention presents a system comprising a light source such as a laser that directs light upon a surface of a magnetic recording medium. The magnetic recording medium has two or more physical marks, and the light striking the magnetic recording medium produces a diffraction pattern. A light detector such as a photodiode detects some or all of the diffraction pattern. The physical marks may be servo tracks on the magnetic recording medium, and the detected diffraction pattern is a function of the characteristics of the servo tracks.
    Type: Grant
    Filed: March 23, 2001
    Date of Patent: September 14, 2004
    Assignee: Imation Corp.
    Inventor: Jathan D. Edwards
  • Patent number: 6791785
    Abstract: A controller for a disk drive that accesses a look up table having a plurality of thermally characterized values corresponding to a plurality of seek operations. For each seek operation, the corresponding value is added to a register. The controller decrements the register at a rate that is determined using servo interrupts occurring as a result of the rotation of the disk. When the value of the register exceeds a threshold, the controller adjusts the subsequent seek operation so as to inhibit damage to the voice coil as a result of overheating.
    Type: Grant
    Filed: February 28, 2001
    Date of Patent: September 14, 2004
    Assignee: Western Digital Technologies, Inc.
    Inventors: Carl R. Messenger, David D. Nguyen
  • Patent number: 6791786
    Abstract: An actuator control system for a two-stage actuator system of a disc drive has a first, or primary, stage actuator consisting of a voice coil motor that positions the head relative to a disc and a microactuator that alters the actuator system without operation of the voice coil motor. A control loop includes a controller responsive to seek commands to operate the voice coil motor, thereby moving the head relative to the disc. An active damping circuit is coupled to the head to operate the microactuator to damp resonance modes of the actuator system.
    Type: Grant
    Filed: December 11, 2000
    Date of Patent: September 14, 2004
    Assignee: Seagate Technology LLC
    Inventors: JianBo He, Joseph Cheng-Tsu Liu, Kevin Gomez, Tao Zhang
  • Patent number: 6791787
    Abstract: Disclosed is an improvement in a tape guide device having an inclined post and a guide roll rising upright on its base for guiding and directing a length of recording tape to the rotary drum on the deck of a video recorder. The base is made of a synthetic resin material, and has an axle hole made therein for press-fitting the axle of the guide roll. The upper end of the axle hole is tapped, and the axle hole has at least one rib projecting inward from its inner circumference. The axle is threadedly engaged with the upper end of the axle hole, and is press-fitted in the axle hole with the rib or ribs pressed and slightly deformed. Thus, the axle can be positively held in the axle hole of the base, preventing the guide roll to shake in the axle hole, still permitting adjustment of the height of the guide roll. Thanks to such ribs the tight insertion of the axle in the axle hole is assured without the necessity of machining or molding with high precision.
    Type: Grant
    Filed: February 19, 2003
    Date of Patent: September 14, 2004
    Assignee: Orion Electric Co., Ltd.
    Inventor: Kouji Azai
  • Patent number: 6791788
    Abstract: A segmented power strip for supplying electrical power to a robotic device for use in a data storage system, the robotic device adapted to move along a guide rail. The power strip includes first and second substantially planar members each having an end and a conductor for making electrical contact with the robotic device. The first and second members are assembled to create a joint where the conductor of the first member is proximate the conductor of the second member such that the robotic device maintains electrical contact with at least one conductor as the robotic device traverses the joint. The ends of the first and second members are adapted to cooperate such that at least one of the first and second members moves laterally relative to the other during assembly thereof. At least one of the first and second members is biased against lateral motion relative to other.
    Type: Grant
    Filed: December 27, 2001
    Date of Patent: September 14, 2004
    Assignee: Storage Technology Corporation
    Inventors: Gary Gustafson, Timothy C. Ostwald
  • Patent number: 6791789
    Abstract: A tape drive (10) for use with a cartridge (24) having a storage tape (30) that moves along a tape path (32) includes a drive housing (12) defining a drive interior (62), a circuit assembly (42) that generates heat, and a thermal insulator (44). In one embodiment, the thermal insulator (44) is positioned between a portion of the storage tape (30) and the circuit assembly (42). The thermal insulator (44) can be formed from a flexible, plastic material and/or can have a thermal conductivity of less than approximately 50 W/mK to decrease the transfer of heat between the circuit assembly (42) and the storage tape (30). The drive interior (62) can have a first region (64) that includes a portion of the tape path (32), and a second region (66) that includes the circuit assembly (42).
    Type: Grant
    Filed: December 12, 2002
    Date of Patent: September 14, 2004
    Assignee: Quantum Corporation
    Inventor: Christopher Rathweg
  • Patent number: 6791790
    Abstract: In a hard disk drive, at least one groove is formed in any of the base plate and the cover plate to pump air toward an outer side of the disk. An outer end of the groove is located at a position inwardly separated from an edge of the disk such that an air journal zone of predetermined width is formed along a circumferential direction of the disk between the outer end of the groove and the edge of the disk. The groove is formed in multiple numbers in a circumferential direction of the disk at a predetermined interval and is extended in a radial direction from an inner side of the disk and curved in a direction in which the disk rotates. Thus, vibration of the disk is reduced by a damping operation of air pumped by the groove having a high pressure in the air journal zone.
    Type: Grant
    Filed: February 11, 2003
    Date of Patent: September 14, 2004
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Hong-kwon Lee
  • Patent number: 6791791
    Abstract: An aspect of the invention can be regarded as a disk drive that includes a disk drive base and a spindle motor hub rotatably coupled to the disk drive base. The disk drive further includes a first disk disposed about the spindle motor hub and having a first disk stiffness. The disk drive further includes a second disk disposed about the spindle motor hub and having a second disk stiffness different than the first disk stiffness. According to another aspect of the present invention, the second disk has a second disk thickness different than a first disk thickness. According to another aspect of the present invention, the second disk is formed of a second material having a second material stiffness different than a first material stiffness.
    Type: Grant
    Filed: November 30, 2001
    Date of Patent: September 14, 2004
    Assignee: Western Digital Technologies, Inc.
    Inventors: Steven J. Alfred, Raffi Codilian, Serge Hauert, Lin Yang
  • Patent number: 6791792
    Abstract: A magnetic field sensor for sensing an applied magnetic field by utilizing a Hall effect. Used, as a sensor portion, are compound materials such as FeN showing a significant anomalous Hall effect, and materials containing magnetic properties such as a magnetic semiconductor having a zincblende structure and oxide having a perovskite structure. A device structure of the magnetic field sensor is adopted, in which by providing a current terminal to a film and a voltage terminal thereof respectively in a film thickness direction and in an in-plane direction, the magnetic field can be guided into the in-plane direction.
    Type: Grant
    Filed: February 19, 2002
    Date of Patent: September 14, 2004
    Assignee: Hitachi, Ltd.
    Inventor: Hiromasa Takahashi
  • Patent number: 6791793
    Abstract: A read/write head and method of making the same, are used in a data storage system, such as a disk drive, for perpendicular magnetic recording of data. The head employs a two-layer pole design with a main pole made of sputtered high moment magnetic material, and an adjunct pole made of electroplated soft magnetic film. The adjunct pole is substantially recessed from the air bearing surface. The present head design significantly enhances the magnetic write field, and substantially reduces side-writing that result in accidental erasure of data in adjacent tracks on the magnetic recording medium.
    Type: Grant
    Filed: September 14, 2001
    Date of Patent: September 14, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Yingjian Chen, Xiaozhong Dang, Francis H. Liu, Kroum Stoev, Hai Jiang, Yugang Wang, Xizeng Shi
  • Patent number: 6791794
    Abstract: By inserting a first antistripping layer comprising a first non-magnetic layer 22 and a first conductive layer 23 between a first magnetic layer 16 and a magnetic separation layer 13, adhesion between the first conductive layer 23 and the magnetic separation layer 13 is improved to prevent the first magnetic layer 16 from stripping. In addition, by inserting a second antistripping layer comprising a second non-magnetic layer 24 and a second conductive layer 25 between a second magnetic layer 21 and a magnetic gap layer 17, adhesion between the second conductive layer 24 and the magnetic gap layer 17 is improved to prevent the second magnetic layer 25 from stripping.
    Type: Grant
    Filed: April 1, 2002
    Date of Patent: September 14, 2004
    Assignee: NEC Corporation
    Inventors: Hiroaki Honjo, Tsutomu Ishi, Mikiko Saito, Shinsaku Saito, Tamaki Toba, Yoshihino Nonaka, Kazuhiko Hayashi, Nobuyuki Ishiwata
  • Patent number: 6791795
    Abstract: A lower magnetic pole front end layer is formed on a lower magnetic pole main layer, and a lower magnetic pole projection layer, a recording gap layer and an upper magnetic pole front end layer each having substantially the same planar shape are formed on a planar surface of the lower magnetic pole front end layer. Trimming of a lower electrode is not necessary, and track width accuracy can be drastically improved because a resist frame is formed on the planar surface. A length of the upper magnetic pole front end layer from an air bearing surface to a head rear direction is greater than a length of the lower magnetic pole front end layer, and the rear end portion of the lower magnetic pole front end layer substantially defines a gap depth.
    Type: Grant
    Filed: August 16, 2002
    Date of Patent: September 14, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Shigekazu Ohtomo, Moriaki Fuyama, Nobuo Yoshida, Hiroshi Fukui
  • Patent number: 6791796
    Abstract: The present invention is a perpendicular writer having an air-bearing surface, a main pole with an extension, and return pole, and a back gap closure intermediate the main pole extension and the return pole. The main pole includes a top magnetic layer and a soft magnetic underlayer separated by a nonmagnetic spacer. The main pole extension is in direct contact with the main pole and recessed from the air-bearing surface. The top magnetic layer forms a trailing edge of the main pole at the ABS and has a magnetic moment greater than that of the soft magnetic underlayer. Further, the top magnetic layer and the soft magnetic underlayer are antiferromagnetically coupled through the thin nonmagnetic spacer. The nonmagnetic spacer has predominantly 111-crystalline texture and promotes reduction of coercivity and grain size along with an increase of anistropy of the top magnetic layer material.
    Type: Grant
    Filed: September 27, 2002
    Date of Patent: September 14, 2004
    Assignee: Seagate Technology LLC
    Inventors: Alexander Mikhailovich Shukh, Vladyslav Alexandrovich Vaśko, Declan Macken
  • Patent number: 6791797
    Abstract: A magnetic recording medium includes a cylindrical substrate and pores embedded with a magnetic substance that are provided on the outer circumferential surface of the cylindrical substrate and aligned in tracks that are in parallel with one another along the center axis of the cylindrical substrate. The tracks have as their center the center axis of the cylindrical substrate, and form circular orbits defined by planes perpendicular to the center axis. Alternatively, the tracks are in a spiral orbit or in spiral orbits whose center is the center axis of the cylindrical substrate. The pores at intersections of vertical and horizontal rows are aligned in quadrilaterals such as squares, rectangles or rhombi.
    Type: Grant
    Filed: March 5, 2003
    Date of Patent: September 14, 2004
    Assignee: Canon Kabushiki Kaisha
    Inventors: Tsatsuya Saito, Tohru Den
  • Patent number: 6791798
    Abstract: A disk drive suspension and method with a low profile limiter structure located within the vertical extent of the slider, the tongue free and any gap provided by the limiter structure so as to not increase the overall vertical extent of the suspension. The limiter structure has a tab separated on three sides from the suspension beam portion and extending from the beam portion locus toward the suspension tongue portion free end. The tab has a projecting shoulder spaced at a gap from the beam portion. The tongue free end outer terminus has an opening that interfits with the tab in tab shoulder engaging relation to block free end movement away from the locus beyond that permitted by the gap.
    Type: Grant
    Filed: November 6, 2001
    Date of Patent: September 14, 2004
    Assignee: Magnecomp Corporation
    Inventor: Shijin Mei
  • Patent number: 6791799
    Abstract: A digital data storage apparatus includes a housing defining a housing interior. A rotatable magnetic media and head arrangement for accessing the media are supported in the housing interior. A flexible circuit stiffener defines a stiffener plane and is directly attached to the housing. A ramp arrangement is directly attachable to the flexible circuit stiffener and is configured for receiving the actuator arm in a parked position when so attached. The ramp arrangement includes an indexing arrangement for engaging the housing in a way which positions the ramp arrangement within at least one controlled tolerance relative to the head arrangement. In one feature, the indexing arrangement is resiliently biased against the housing. In a related feature, the housing defines a ramp indexing recess and an indexing pin of the ramp arrangement is resiliently biased into the indexing recess to locate the indexing pin with the controlled tolerance.
    Type: Grant
    Filed: December 6, 2002
    Date of Patent: September 14, 2004
    Assignee: Convergent Systems Solutions LLC
    Inventor: John F. Fletcher
  • Patent number: 6791800
    Abstract: There is disclosed a disk drive having a magnetic device for applying a direct current magnetic field to the disk 1 by using a disk with a double-layered structure in which a soft magnetic layer is provided on a lower layer of the recording magnetic layer. The magnetic device generates a direct current magnetic field to uniform a magnetic domain state of the soft magnetic layer of the disk. The intensity of the direct current is larger than the anisotropic magnetic field of the soft magnetic layer and is smaller than the coercive force of the recording magnetic layer. As a consequence, the stabilization of the magnetic domain state of the soft magnetic layer of the disk can be realized to make an attempt of decreasing the magnetic noise and establishing stabilization with respect to the disturbance magnetic field.
    Type: Grant
    Filed: August 31, 2001
    Date of Patent: September 14, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Akihiko Takeo, Yoichiro Tanaka
  • Patent number: 6791801
    Abstract: A pivot bearing cartridge for use in a head stack assembly. The cartridge includes a pivot shaft including a central axis, a shaft body and a shaft distal end. The cartridge includes a pivot sleeve disposed about the pivot shaft. The pivot sleeve includes a pivot sleeve annular body and a pivot sleeve closed end disposed adjacent the shaft distal end. The cartridge includes a ball bearing set disposed between and in mechanical communication with the shaft body and the pivot sleeve annular body. The cartridge includes a shaft magnet element attached to the shaft distal end adjacent the pivot sleeve closed end. The shaft magnet element is sized and configured to apply a magnetic force to the pivot sleeve in a direction along the central axis for pre-loading the ball bearing set.
    Type: Grant
    Filed: February 28, 2002
    Date of Patent: September 14, 2004
    Assignee: Western Digital Technologies, Inc.
    Inventor: Kamran Oveyssi
  • Patent number: 6791802
    Abstract: The present invention provides a magnetic head device exhibiting a good bonded state of a piezoelectric element and a load beam, and excellent reliability. The magnetic head device includes a slider provided with a reproducing element for detecting a magnetic signal recorded on a recording medium, and a recording element for recording a magnetic signal on the recording medium, an elastic supporting member for supporting the slider, and piezoelectric elements mounted on the elastic supporting member, for distorting the elastic supporting member to change the position of the slider. The piezoelectric element and the elastic supporting member are bonded together with a photo-curing and thermosetting epoxy adhesive resin having a Young's modulus of 1 GPa or more at 25° C., and a glass transition temperature of 90° C. or more.
    Type: Grant
    Filed: February 21, 2002
    Date of Patent: September 14, 2004
    Assignee: Alps Electric Co., Ltd.
    Inventors: Mitsuru Watanabe, Hidezi Sato
  • Patent number: 6791803
    Abstract: Provided are a method of magnetic recording and reproducing capable of permitting high density recording on magnetic recording media even under the condition of high data transfer rates and yielding adequate recording and reproduction characteristics when an MR head is used in reproduction, and a magnetic recording medium capable of being used in this magnetic recording and reproducing method. The magnetic recording and reproducing method is a method for reproducing a signal magnetically recorded on a magnetic recording medium with a magnetoresistive (MR) head. The magnetic recording medium comprises a substantially nonmagnetic lower layer and a magnetic layer comprising a hexagonal ferrite ferromagnetic powder and a binder in this order on at least one side of a nonmagnetic support, in which said hexagonal ferrite ferromagnetic powder has a mean plate diameter ranging from 15 to 40 nm and a mean plate thickness ranging from 4 to 15 nm, and said magnetic layer has a coercive force Hc ranging from 143.
    Type: Grant
    Filed: August 15, 2002
    Date of Patent: September 14, 2004
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Shinji Saito, Nobuo Yamazaki, Hitoshi Noguchi
  • Patent number: 6791804
    Abstract: A magnetoresistive-effect device includes a multilayer film, hard bias layers arranged on both sides of the multilayer film, and electrode layers respectively deposited on the hard bias layers. The electrode layers are formed, extending over the multilayer film. Under the influence of the hard bias layers arranged on both sides of the multilayer, the multilayer film, forming the magnetoresistive-effect device, has, on the end portions thereof, insensitive regions which exhibit no substantial magnetoresistive effect. The insensitive region merely increases a direct current resistance. By extending the electrode layers over the insensitive regions of the multilayer film, a sense current is effectively flown from the electrode layer into the multilayer film. With a junction area between the electrode layer and the multilayer film increased, the direct current resistance is reduced, while the reproduction characteristics of the device are thus improved.
    Type: Grant
    Filed: January 6, 2003
    Date of Patent: September 14, 2004
    Assignee: Alps Electric Co., Ltd.
    Inventors: Daigo Aoki, Naoya Hasegawa, Kenji Honda, Yoshihiko Kakihara
  • Patent number: 6791805
    Abstract: A giant magnetoresistive (GMR) stack configured to operate in a current-perpendicular-to-plane (CPP) mode includes a ferromagnetic free layer, at least one synthetic antiferromagnet, at least one nonmagnetic spacer layer, and at least one antiferromagnetic pinning layer. The ferromagnetic free layer has a rotatable magnetic moment. The synthetic antiferromagnet includes a ferromagnetic reference layer having a fixed magnetic moment, a ferromagnetic pinned layer having a fixed magnetic moment, and a coupling layer positioned between the reference layer and the pinned layer, wherein the coupling layer is selected from the group consisting of Cu, Ag and CuAg. The nonmagnetic spacer layer is positioned between the free layer and the synthetic antiferromagnet. The antiferromagnetic pinning layer is positioned adjacent to the synthetic antiferromagnet.
    Type: Grant
    Filed: April 1, 2002
    Date of Patent: September 14, 2004
    Assignee: Seagate Technology LLC
    Inventors: Olle Gunnar Heinonen, Michael Seigler, Eric W. Singleton
  • Patent number: 6791806
    Abstract: A tunneling magnetoresistive stack configured to operate in a current-perpendicular-to-plane mode has a plurality of layers including a barrier layer. The TMR stack has a plurality of layers including a barrier layer, wherein the barrier layer is comprised of an insulating material selected from a group consisting of HfO, HfAlO, ZrO, TiO, TaO or NdO. The TMR stack exhibits a low resistance-area (RA) product, a stable magnetoresistive (MR) ratio, a lower RA product, a higher breakdown voltage of the TMR stack and enhanced thermal stability.
    Type: Grant
    Filed: August 9, 2002
    Date of Patent: September 14, 2004
    Assignee: Seagate Technology LLC
    Inventors: Zheng Gao, Sining Mao, Khoung Tran, Janusz Nowak, Jian Chen
  • Patent number: 6791807
    Abstract: A spin-valve magnetic transducing element. In one embodiment, a spin-valve magnetic transducing element is disclosed in which a ferromagnetic tunneling junction film, including first and second ferromagnetic layers and an insulating layer is enclosed between the ferromagnetic layers. A nonmagnetic metal thin film is inserted between the second ferromagnetic layer and the insulating layer, all of which are formed on a substrate.
    Type: Grant
    Filed: June 4, 1999
    Date of Patent: September 14, 2004
    Assignee: Read-Rite SMI Corporation
    Inventors: Fuminori Hikami, Hideyasu Nagai, Masaki Ueno, Marcos M. Lederman, Hirohiko Kamimura, Masahiko Ando, Kenji Komaki
  • Patent number: 6791808
    Abstract: A clipping device intended for absorbing current peaks from 1 to 10 amperes, formed of a vertical NPN transistor, having an unconnected base, an emitter connected to a terminal on which positive voltage peaks are likely to appear, and a grounded collector, the transistor parameters being set so that it exhibits a negative dynamic resistance.
    Type: Grant
    Filed: December 22, 2000
    Date of Patent: September 14, 2004
    Assignee: STMicroelectronics S.A.
    Inventors: Eric Bernier, Robert Pezzani
  • Patent number: 6791809
    Abstract: A charge/discharge protection circuit with n parallel load current switches and a control logic for the latter, which in an over-voltage event disconnects the battery from the charge/discharge terminals through sequentially controlled melting of integrated fusible links, where the control logic in an over-voltage event, simultaneously closes all load current switches, then following sequentially opens a first number of the load current switches, and at the same time closes the switch segments of a short-circuit switch array associated with the respective load current switch, so that the associated fusible links melt sequentially. After the opening of this first number of load current switches the latter closes again and at the same time the remaining number of still closed load current switches opens, as well as continues to sequentially close the remaining switch segments.
    Type: Grant
    Filed: November 26, 2002
    Date of Patent: September 14, 2004
    Assignee: Dialog Semiconductor GmbH
    Inventor: Axel Pannwitz
  • Patent number: 6791810
    Abstract: There is provided a protection circuit of a field effect transistor having a structure which can be fabricated without restricting a pattern layout and without increasing a process step. A protection circuit of a field effect transistor is a protection circuit of a Schottky gate HFET, and is a circuit in which a forward direction diode and a reverse direction diode are cascade-connected to form a diode unit and two such diode units are connected in series, and a gate line connected to a gate electrode of the HFET is grounded through the protection circuit. The diodes are diodes formed integrally with the Schottky gate HFET which is protected against surge breakdown, and are constituted as Schottky barrier diodes made of an n+-GaAs cap layer formed on a GaAs substrate and Schottky electrodes formed on the n+-GaAs cap layer.
    Type: Grant
    Filed: May 22, 2001
    Date of Patent: September 14, 2004
    Assignee: Sony Corporation
    Inventors: Mitsuhiro Nakamura, Shinichi Wada
  • Patent number: 6791811
    Abstract: A current sense circuit includes a current sense device and a voltage sense device. The current sense device is positioned to sense a drive current provided to a load by a drive circuit. The voltage sense device is coupled across the current sense device and receives a threshold signal at a first input and provides an output signal on an output whose value is dependent upon whether a sense signal at a second input is above or below the threshold signal. A level of the threshold signal changes in response to a voltage level of a power supply that supplies the drive current to the drive circuit.
    Type: Grant
    Filed: October 8, 2003
    Date of Patent: September 14, 2004
    Assignee: Gentex Corporation
    Inventors: G. Bruce Poe, Robert R. Turnbull
  • Patent number: 6791812
    Abstract: Surge protector which includes a film pattern (2) formed on a suitable substrate (1) is characterized in that the film pattern (2) essentially consists of narrow lines (2a, 2b, 2c) which extend parallel and adjacent to each other and are electrically in parallel relationship to each other, and bridges (11-24) between the lines. Advantageously, there are three parallel lines. The resistance of the film pattern (2) is trimmed advantageously by cutting (T5, T6, T7, T8, T9, T10) one of the lines (2c) between successive bridges.
    Type: Grant
    Filed: December 13, 2000
    Date of Patent: September 14, 2004
    Assignee: Nokia Networks Oy
    Inventor: Hannu Määttä
  • Patent number: 6791813
    Abstract: The present invention relates to a communication line surge protecting system in which a quarter wavelength open circuit for a wavelength used is disposed in each of a central conductor line 1 and an external conductor line 2 so as to allow a signal with a predetermined communication wavelength to pass therethrough, while blocking signals with frequency components of lighting surge and the like, and in which a ground line is further provided in the central conductor line and a quarter wavelength short circuit for the wavelength used is disposed in each of the ground line and the external conductor line so as to block the signal with the predetermined communication wavelength, while allowing the signals with the frequency components of lighting surge and the like to pass therethrough. The signal of the predetermined wavelength used passes through the communication line and is insulated from the ground.
    Type: Grant
    Filed: August 23, 2002
    Date of Patent: September 14, 2004
    Assignees: NTT Docomo Kyushu, Inc., Sankosha Corporation
    Inventors: Takashi Shikano, Kiyotaka Ando, Chikashi Okabayashi
  • Patent number: 6791814
    Abstract: An ion generating apparatus 1 has an electric cleaning mechanism 79 for burning out attachment adhered on an ion generating electrode 7 by electric heating. Adhesion of dirt and the like onto the end portion of the electrode where an electron generation field concentrates will considerably ruin the ion generation efficiency. So that burning out of attachment adhered onto the end portion 7a of the ion generating electrode 7 using the electric cleaning mechanism 79 is extremely effective in terms of avoiding such nonconformity. Object of the cleaning will be attained to a sufficient degree if only the dirt adhered onto the sharpened end portion of the electrode 7, which is responsible for the ion generation, is selectively removed, which is also advantageous in simplifying the apparatus since there is no need to excessively raise the electric heating capacity of the electric cleaning mechanism 79.
    Type: Grant
    Filed: June 10, 2002
    Date of Patent: September 14, 2004
    Assignee: Nihon Pachinko Parts Co., Ltd.
    Inventors: Yoshiichi Adachi, Yuji Kato
  • Patent number: 6791815
    Abstract: Concentrations of positive and negative ions that are generated in the ambient air at a selected location are controlled in time-varying manner. Apparatus for generating air ions includes controllable high voltage sources and electrodes connected to the sources adapted to generate positive ions and negative ions in ambient air near the electrodes. Control circuitry is coupled to the high voltage sources to control the voltage levels at the electrodes for altering the quantities of positive ions and/or negative ions that are generated in time-varying manner within the ambient air about the electrodes. The control circuitry may control the voltage sources to generate a simulated ion signature of variations in ion concentrations as detected at a selected geographic location.
    Type: Grant
    Filed: October 27, 2000
    Date of Patent: September 14, 2004
    Assignee: ION Systems
    Inventor: Martin Graham
  • Patent number: 6791816
    Abstract: Multiple embodiments of a personal defense device each include an electrical stun circuit and electrodes with a structure adapted for use as an impact weapon as well, and further include a radially disposed flashlight or signal light therewith. The electrical circuitry for the stun apparatus may be formed of flexible circuit material with dual circuit paths between each component, for reliability and resistance to damage due to impact forces incurred when the device is used as an impact weapon. A second, normally closed interrupter switch may be provided for the stun circuit, with the user of the present device being required to hold the interrupter switch in order to keep the stun circuitry from operating when the master switch is turned on. The end opposite the handle may include a series of impact ribs with cutting blades removably installable thereon, to produce non-lethal cuts in an assailant during an attack.
    Type: Grant
    Filed: February 28, 2003
    Date of Patent: September 14, 2004
    Inventor: Kenneth J. Stethem
  • Patent number: 6791817
    Abstract: The invention provides an electro-adhesion device (10) including a base (12) and first (14) and second (16) banks of thin electrically conductive electrodes (18) located apart from each other on a side of the base (12). The electro-adhesion device (10) also includes an insulating cover (20) over the first (14) and second (16) banks so that the outer side of the insulating cover (20) defines an electro-adhesion surface so that, in use, when the electrodes (18) are energized and an object to be attracted is placed adjacent the insulating cover (20), the object is attracted to the insulating cover (20) by a suitably high adhesion force. An outer surface (24) of each of the electrodes (18) has a linear border on one side and a sinusoidal border on an opposite side so that the width of each electrode (18) varies sinusoidally lengthwise along the electrode (18).
    Type: Grant
    Filed: December 13, 2002
    Date of Patent: September 14, 2004
    Inventors: Herman Allison, Ronald Kevin Fricker, Marthinus Christoffel Smit
  • Patent number: 6791818
    Abstract: An electrode of an electronic device includes plural nickel layers adjacent to each other, and an outer nickel layer contains less phosphorus than an inner nickel layer. The electrode has an increased solder joining strength without having a flexural strength decreased.
    Type: Grant
    Filed: June 12, 2003
    Date of Patent: September 14, 2004
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Koji Shimoyama, Yoshihisa Takase
  • Patent number: 6791819
    Abstract: A capacitor module incorporating a ceramic capacitor having terminal members for reducing stress caused by thermal stress or electrostriction in the ceramic capacitor itself, and a semiconductor device using the capacitor module. The capacitor module and the semiconductor device are designed to have a reduced size and improved reliability.
    Type: Grant
    Filed: April 3, 2002
    Date of Patent: September 14, 2004
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tohru Kimura, Dai Nakajima, Yuuji Kuramoto
  • Patent number: 6791820
    Abstract: The invention relates to electrical engineering and can be used for developing energy-storing devices. The inventive electrochemical double-layer capacitor makes it possible to develop an operable device having a long service life in addition to high specific energy and power. Said electrochemical double layer capacitor comprises a molten electrolyte (4) provided with a gelling agent.
    Type: Grant
    Filed: September 9, 2003
    Date of Patent: September 14, 2004
    Assignee: Universal Resources AG
    Inventors: Igor N. Varakin, Alexey B. Stepanov, Victor V. Samitin
  • Patent number: 6791821
    Abstract: An improved tantalum-carbon capacitor employs activated carbon in place of expensive metals to achieve a large surface area, and therefore higher capacitance, but at substantially lower cost than can be achieved using expensive metals to increase surface area. The capacitor includes a tantalum case, a tantalum anode, a dielectric layer on the anode, an electrolyte in contact with the dielectric layer on the anode, a layer of tantalum carbide on an inner surface of the case, and a layer of activated carbon between the layer of tantalum carbide and the electrolyte.
    Type: Grant
    Filed: October 16, 2001
    Date of Patent: September 14, 2004
    Assignee: Yosemite Investment, Inc.
    Inventor: Mark T. Monnett
  • Patent number: 6791822
    Abstract: A first capacitor element of a sheet form includes a porous valve metal film, a dielectric layer provided on the porous valve metal film, a solid electrolyte layer provided on the dielectric layer, and a collector layer provided on the solid electrolyte layer. A second capacitor element of a sheet form includes a valve metal film, a porous valve metal body provided on the valve metal film, a dielectric layer provided on the porous valve metal body, a solid electrolyte layer provided on the dielectric layer, and a collector layer provided on the electrolyte layer. The first and second capacitor elements are stacked. The porous valve metal film of the first capacitor element and the valve metal film of the second capacitor element are connected to one external electrode while the collector layers of the first and second capacitor elements are connected to another external electrode, thus providing a solid electrolytic capacitor.
    Type: Grant
    Filed: June 6, 2003
    Date of Patent: September 14, 2004
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Ayumi Kochi, Seiji Takagi, Yuji Mido, Tetsuhiro Korechika
  • Patent number: 6791823
    Abstract: An electrolysis solution for electrolytic capacitors including an aqueous organic solvent consisting of water and a water-compatible organic solvent and 1,6-decane-dicarboxylic acid or salt thereof dissolved therein. The solution further contains one or more additives selected from dinitriles, pivalic acid and salts thereof, diesters, alkylated lactones, cyanoalkanoic esters, monocarbboxylic acids each having a C3-7 alkyl chain and substituted with two C1-4 alkyl groups at the &bgr;-position to the carboxyl group and salts thereof, monocarboxylic acids each having C3-7 alkyl chain and substituted with one ethyl group at the &agr;-position to the carboxyl group and salts thereof, and monocarboxylic acids derived from cyclic saturated compounds each having five or six ring-constituting carbon atoms and salts thereof.
    Type: Grant
    Filed: July 15, 2003
    Date of Patent: September 14, 2004
    Assignee: UBE Industries, Ltd
    Inventors: Koji Abe, Yasuo Matsumori, Motoki Yuguchi, Akikazu Ito, Toshikazu Hamamoto, Yoshihiro Ushigoe