Patents by Inventor Wai C. Leung

Wai C. 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: 6477008
    Abstract: The present invention is a read/write head for writing information to magnetic media and reading information from magnetic media. It includes a write head element for writing information onto magnetic media, a read head element for reading information from the magnetic media, and an electromagnetic field shield element that is disposed between the write head element and the read head element. The shield functions to shield the read head from electromagnetic field energy created by the write head element. An enhanced second embodiment includes an electrical circuit element that is disposed proximate the read head element that functions to generate an electromagnetic field at the read head element that is generally oppositely directed to the electromagnetic field generated by the write head element to reduce the total electromagnetic field that the read head element is exposed to during a writing operation.
    Type: Grant
    Filed: May 24, 1999
    Date of Patent: November 5, 2002
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Shanlin Duan, Terence Tin-Lok Lam, Wai C. Leung
  • Patent number: 6407891
    Abstract: The present invention is a read/write head for writing information to magnetic media and reading information from magnetic media. It includes a write head for writing information onto magnetic media, a read head for reading information from the magnetic media, and an electrical circuit element that is disposed proximate the read head that functions to generate an electromagnetic field at the read head that is generally oppositely directed to the electromagnetic field generated by the write head. The method for operating the read/write head in a hard disk drive, includes the steps of writing data onto a hard disk, while simultaneously generating an electromagnetic field at the read head that is directed oppositely to the electromagnetic field generated by the write head.
    Type: Grant
    Filed: May 24, 1999
    Date of Patent: June 18, 2002
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Shanlin Duan, Terence Tin-Lok Lam, Wai C. Leung
  • Patent number: 6357095
    Abstract: The burnishing head for hard disk processing includes a solid body having generally rectangular surfaces, including an upper surface, a burnishing pad surface, a front surface, a rear surface and two side surfaces. A plurality of burnishing pads are disposed upon the burnishing pad surface. The pads are shaped such that each pad has a burnishing edge that is generally parallel to said front surface and therefore orthogonal to the direction of media travel. The burnishing pads are preferably configured such that one frontward leading pad is centrally disposed proximate the front surface of the head, followed by two middle pads that are disposed in a spaced apart relationship. A single centrally disposed rear middle pad is formed behind the two middle pads, and two rear pads are disposed in a spaced apart relationship at the rear surface of the head. In the preferred embodiment the pads are generally triangular in shape and the outer surface of the leading and rearward pads is tapered.
    Type: Grant
    Filed: July 23, 1999
    Date of Patent: March 19, 2002
    Assignee: International Business Machines Corporation
    Inventors: Shanlin Duan, Wei-Ming Lee, Wai C. Leung
  • Patent number: 6330122
    Abstract: The hard disk testing and certifying device of the present invention includes a spin stand to rotate a disk to be tested. A single read/write head, including both a write head and a read head is mounted upon an armature which movably supports the read/write head. The device includes a computerized control system and signal processing system that provides write signals to the write head and receives and processes read head signals from the read head. In the preferred embodiment the read/write head simultaneously provides write signals to the disk and receives read signals from the disk. Preferably, the read/write head functions continually and the certification testing is conducted utilizing a spiral path. In the preferred read/write head the read head is disposed behind the write head and an electromagnetic field shield is disposed between them to reduce electromagnetic field interference between the write head and the read head during simultaneous operation.
    Type: Grant
    Filed: May 24, 1999
    Date of Patent: December 11, 2001
    Assignee: International Business Machines Corporation
    Inventors: Thomas Young Chang, Shanlin Duan, Terence Tin-Lok Lam, Wai C. Leung
  • Patent number: 6081411
    Abstract: The hard disk drive manufacturing method of the present invention includes an initial determination of the orientation of the individual hard disks during the various processing steps and disk drive assembly steps. Specifically, the orientation of the hard disks in the assembled disk drive is ascertained, such that the direction of arcuate writing paths on the disk surface is known. Additionally, the orientation of non-random arcuate micro-scratches that appear on the disk surface during disk processing is ascertained. Where the arcuate path of the micro-scratches corresponds to the arcuate writing paths on a disk surface, the disk process is altered to effectively reorient the disk in its mounting in the hard disk drive. The result of the process alteration is that there is no longer a correspondence between the arcuate path of the micro-scratches and the arcuate written data paths, and a significant reduction in the number of defects on the surface of the hard disk is obtained.
    Type: Grant
    Filed: June 29, 1998
    Date of Patent: June 27, 2000
    Assignee: International Business Machines Corporation
    Inventors: Paul M. Green, Wai C. Leung
  • Patent number: 5079086
    Abstract: The magnetic recording layer of a recording medium contains a film-forming resin, magnetic particles, poly(ethyleneimine), and an amionic surfactant.
    Type: Grant
    Filed: October 11, 1990
    Date of Patent: January 7, 1992
    Assignee: International Business Machines Corp.
    Inventors: John M. Burns, Walter Crooks, Wai C. Leung, Randall G. Simmons, Clinton D. Snyder
  • Patent number: 4873430
    Abstract: A method for optically measuring at least one characteristic of a thin film on a reflecting substrate. A p-polarized beam of collimated light of known intensity is directed through an integrating sphere onto the film at substantially the Brewster's angle of the film. All the light is reflected into the sphere, including all diffusely reflected light as well as the light specularly reflected at a region inside the sphere where the specularly reflected light is incident. A reflective surface is provided for determining the thickness of the film as a function of the total intensity of light sensed within the sphere. An absorptive surface is provided at said region for absorbing the specularly reflected light for determining the porosity or surface roughness of the film based on the intensity of the diffused light sensed within the sphere not reflected from the substrate.
    Type: Grant
    Filed: October 25, 1988
    Date of Patent: October 10, 1989
    Assignee: International Business Machines Corporation
    Inventors: Anthony Juliana, Wai C. Leung, Victor T. Pan, Hal J. Rosen, Timothy C. Strand