Patents by Inventor Chak M. Leung

Chak M. Leung 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: 8840560
    Abstract: A hand-operated intracardiac echocardiography (ICE) catheter is described for flexed and rotational steering is described for improved catheter operation, control and less trauma on patients. The disclosed catheter assembly includes ultrasound transducers mounted upon a rotatable tip mounted on a distal end of a flexible elongate shaft. A set of steering lines are controlled by a steering actuator to articulate bidirectionally a distal segment of the catheter. Another steering actuator controls rotation of a torque member that, in turn is coupled to the rotatable tip. A user, through the steering actuators, affects repositioning the ultrasonic transducers by repositioning exposed control surfaces of the steering actuators lengthwise along the housing of the handle.
    Type: Grant
    Filed: April 4, 2007
    Date of Patent: September 23, 2014
    Assignee: Volcano Corporation
    Inventors: Norman Hugh Hossack, Richard Scott Huennekens, Rovil Rae Pascual Arcia, Ernest W. Heflin, Stephen C. Davies, Richard Klosinski, Blair D. Walker, Chak M. Leung
  • Patent number: 6002552
    Abstract: A head gimbal assembly includes an adaptive loading/unloading suspension with an aerodynamic compensation mechanism formed with or attached to the load beam. The compensation mechanism causes a variable and programmable dynamic gram load to be applied on the suspension such that a low gram load is achieved at the time of dynamic head loading, thus significantly minimizing or totally eliminating head-to-disk contact. The variable suspension gram load feature can be combined with an air slider bearing design to achieve optimal flying height performance and cost effectiveness. Such combination provides the air bearing design with an additional degree of freedom to achieve a more uniform flying height and improved altitude sensitivity than under a constant preload.
    Type: Grant
    Filed: January 19, 1999
    Date of Patent: December 14, 1999
    Assignee: Read-Rite Corporation
    Inventor: Chak M. Leung
  • Patent number: 5959806
    Abstract: A head gimbal assembly includes an adaptive loading/unloading suspension with an aerodynamic compensation mechanism formed with or attached to the load beam. The compensation mechanism causes a variable and programmable dynamic gram load to be applied on the suspension such that a low gram load is achieved at the time of dynamic head loading, thus significantly minimizing or totally eliminating head-to-disk contact. The variable suspension gram load feature can be combined with an air slider bearing design to achieve optimal flying height performance and cost effectiveness. Such combination provides the air bearing design with an additional degree of freedom to achieve a more uniform flying height and improved altitude sensitivity than under a constant preload.
    Type: Grant
    Filed: June 12, 1997
    Date of Patent: September 28, 1999
    Assignee: Read-Rite Corporation
    Inventor: Chak M. Leung
  • Patent number: 5727308
    Abstract: A magnetic head is formed by depositing a pad pattern on a substrate with a flat upper surface. The pad pattern includes two spaced inner slopes that face each other. An air bearing surface plane is defined between the inner slopes where the air bearing surface of the magnetic head is to be formed. An undercoat layer is deposited on the pad pattern, such that the undercoat layer follows the contour of the inner slopes to form a recessed region between the inner slopes. A magnetic layer is deposited on the undercoat layer to form a first pole P1 that follows the contours of the inner slopes. A gap layer is then formed on top of the first pole P1 and follows its contour. Conductive coils are formed within the recessed region. A second magnetic layer is deposited over the coils and gap layer to form a second pole P2. The magnetic head is lapped at the air bearing surface plane to form the final air bearing surface.
    Type: Grant
    Filed: July 25, 1996
    Date of Patent: March 17, 1998
    Assignee: Read-Rite Corporation
    Inventors: Chak M. Leung, Charles R. Bond, Daniel A. Nepela
  • Patent number: 5535074
    Abstract: The headstack of a disk drive is formed with separate sections, each of which supports a plurality of head suspensions. In one embodiment, the sections are blocks on which pairs of head suspensions having UP and DOWN facing sliders are mounted. The blocks are individually positioned and aligned relative to a disk stack. In a second embodiment, head suspensions are supported by a pair of modules. A first module supports suspensions with UP head sliders and a second module supports suspensions with DOWN head sliders. The modules interlock so that an alternating arrangement of UP and DOWN heads result. By use of a comb-like head loading tool, the suspensions that carry the head sliders are spaced and loaded to respective disk surfaces.
    Type: Grant
    Filed: January 9, 1995
    Date of Patent: July 9, 1996
    Assignee: Read-Rite Corporation
    Inventor: Chak M. Leung
  • Patent number: 5473485
    Abstract: A tripad air bearing slider useful in a disk drive is designed with two outer pads that extend from two or more tapered sections at the leading edge of the slider towards the trailing edge. The pads are configured and angled so that a desired lift force is obtained that acts in opposition to a force provided by a spring loaded flexure or load beam. The angles that define the shape of the three pads are formed by simple mechanical cutting, using a diamond cutting wheel, for example, or alternatively by ion milling or reactive ion etching.
    Type: Grant
    Filed: February 6, 1995
    Date of Patent: December 5, 1995
    Assignee: Read-Rite Corporation
    Inventors: Chak M. Leung, Carroll S. Gooden, Edgar M. Williams
  • Patent number: 5359480
    Abstract: An air bearing slider of a thin film magnetic head assembly is configured with tapered portions at its leading edge and with two side rails extending from the tapers to the trailing edge of the slider. Recesses that are formed in the rails are spaced from the tapered portions. Each rail may be configured with one or more recesses. In one embodiment, the two recesses of each rail are asymmetrically disposed relative to the tapered portion of the rail and to the trailing edge of the slider. In such embodiment, the recesses do not extend to the slider trailing edge. In alternative embodiments, the recesses are spaced from the tapered portions but extend to the trailing edge of the slider. The recesses may be arcuately shaped or have angled portions or other geometries.
    Type: Grant
    Filed: December 21, 1992
    Date of Patent: October 25, 1994
    Assignee: Read-Rite Corporation
    Inventors: Daniel A. Nepela, Chak M. Leung, Ciuter Chang
  • Patent number: 5327310
    Abstract: A thin film magnetic head assembly useful for contact recording in a disk drive comprises an air bearing slider formed with only a single air bearing rail. The slider is substantially L-shaped having a leg portion on which a pedestal with an air bearing surface is provided. A wear pad is formed on the pedestal and encompasses the pole tips and transducing gap of the transducer. The wear pad makes contact with the magnetic disk during operation of the disk drive. The small area of the wear pad makes minimal contact with the surface of the magnetic disk so that frictional effects are significantly reduced thereby extending the wear life of the magnetic head. An alternative embodiment of a contact head slider uses a tripad design wherein the front pads fly relative to the disk and the rear pad which supports the transducer is in contact with the rotating disk during operation of a disk drive.
    Type: Grant
    Filed: June 25, 1992
    Date of Patent: July 5, 1994
    Assignee: Read-Rite Corporation
    Inventors: Peter G. Bischoff, Chak M. Leung, Stephen S. Murray
  • Patent number: 5312644
    Abstract: A thin-film magnetoresistive playback head having films providing magnetic shielding and magnetic bias. At least one of the magnetic shield layers is also conductive so that the functions of shielding and biasing are combined. Preferably, both shield layers are conductive. A multiple element channel head is disclosed in which the magnetic/conductive layers extend in series from one transducer section to the next, allowing a single bias current to bias all of the sections.
    Type: Grant
    Filed: September 17, 1993
    Date of Patent: May 17, 1994
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Theodore A. Schwarz, Peter G. Bischoff, Chak M. Leung, Johnny C. Chen, Pradeep Thayamballi
  • Patent number: 5311385
    Abstract: A thin-film magnetoresistive playback head having films providing magnetic shielding and magnetic bias. At least one of the magnetic shield layers is also conductive so that the functions of shielding and biasing are combined. Preferably, both shield layers are conductive. A multiple element channel head is disclosed in which the magnetic/conductive layers extend in series from one transducer section to the next, allowing a single bias current to bias all of the sections.
    Type: Grant
    Filed: December 18, 1991
    Date of Patent: May 10, 1994
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Theodore A. Schwarz, Peter G. Bischoff, Chak M. Leung, Johnny C. Chen, Pradeep Thayamballi
  • Patent number: 5299081
    Abstract: A magnetic head suspension assembly is fabricated with a load beam formed with a central triangular-type major section, a tongue section at the front end and a rigid mount section at the opposing rear end. The load beam has flanges along the sides of the central major section and the rear mount section. A leaf spring is provided between the central major section and the rear mount section for providing flexibility to the suspension. A flexure that is joined to the load beam is formed with a U-shaped finger surrounded by a cutout at the front end of the flexure. A load dimple that is provided on the flexure is in contact with the load beam. The flexure supports an air bearing slider that pitches and rolls relative to a disk surface. The flexure does not extend beyond the load dimple of the flexure or the front leading edge of the slider. The suspension is characterized by a high first bending mode frequency and low pitch and roll stiffness.
    Type: Grant
    Filed: August 5, 1992
    Date of Patent: March 29, 1994
    Assignee: Read-Rite Corporation
    Inventors: Michael R. Hatch, Chak M. Leung, Stephen S. Murray
  • Patent number: 5282103
    Abstract: A magnetic head suspension assembly is fabricated with an integral piece which includes a load beam section, a flexure section, a rear mount section and a leaf spring section between the load beam and rear mount. A tongue extends from the load beam to the flexure and has a down-facing load dimple which contacts the non-air bearing surface of an attached air bearing slider. The flexure includes narrow thin legs adjacent to a cutout that delineates the load beam tongue. The head suspension is characterized by a high first bending mode frequency and low pitch and roll stiffness.
    Type: Grant
    Filed: April 5, 1993
    Date of Patent: January 25, 1994
    Assignee: Read-Rite Corporation
    Inventors: Michael R. Hatch, Chak M. Leung
  • Patent number: 5237476
    Abstract: A thin film tape head assembly is formed by depositing a multiplicity of thin film transducers on a ceramic wafer or substrate. The wafer is divided into head bars, each of which has one or more thin film transducers on its face. End sections and a cover bar are joined to the head bar to form a head bar subassembly. A flexible cable or electrical pins are provided between the end sections to enable electrical connection between the head circuit and external circuitry. By joining a number of head bar subassemblies, a multigap thin film tape head assembly is produced to serve as a read/write device.
    Type: Grant
    Filed: May 28, 1991
    Date of Patent: August 17, 1993
    Assignee: Read-Rite Corp.
    Inventors: Peter G. Bischoff, Carroll S. Gooden, Chak M. Leung
  • Patent number: RE39478
    Abstract: A magnetic head suspension assembly is fabricated with an integral piece which includes a load beam section, a flexure section, a rest mount section and a leaf spring section between the load beam and rear mount. A tongue extends from the load beam to the flexure and has a down-facing load dimple which contacts the non-air bearing surface of an attached air bearing slider. The flexure includes narrow thin legs adjacent to a cutout that delineates the load beam tongue. The head suspension is characterised by a high first bending mode frequency and low pitch and roll stiffness.
    Type: Grant
    Filed: June 13, 1996
    Date of Patent: January 23, 2007
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Michael R. Hatch, Chak M. Leung
  • Patent number: RE40203
    Abstract: A magnetic head suspension assembly is fabricated with an integral piece which includes a load beam section, a flexure section, a rear mount section and a leaf spring section between the load beam and rear mount. A tongue extends from the load beam to the flexure and has a down-facing load dimple which contacts the non-air bearing surface of an attached air bearing slider. The flexure includes narrow thin legs adjacent to a cutout that delineates the load beam tongue. The head suspension is characterized by a high first bending mode frequency and low pitch and roll stiffness.
    Type: Grant
    Filed: June 13, 1996
    Date of Patent: April 1, 2008
    Assignee: Western Digital (Fremont), LLC
    Inventors: Michael R. Hatch, Chak M. Leung
  • Patent number: RE41401
    Abstract: A magnetic head suspension assembly is fabricated with an integral piece which includes a load beam section, a flexure section, a rear mount section and a leaf spring section between the load beam and rear mount. A tongue extends from the load beam to the flexure and has a down-facing load dimple which contacts the non-air bearing surface of an attached air bearing slider. The flexure includes narrow thin legs adjacent to a cutout that delineates the load beam tongue. The head suspension is characterized by a high first bending mode frequency and low pitch and roll stiffness.
    Type: Grant
    Filed: July 30, 2003
    Date of Patent: June 29, 2010
    Assignee: Western Digital (Fremont), LLC
    Inventors: Michael R. Hatch, Chak M. Leung