Patents by Inventor Andrew Ching Tam

Andrew Ching Tam 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: 6108170
    Abstract: A row of magnetic read/write sliders which have scribe lines on a back surface. The scribe lines provide an accurate curvature for the air bearing surface which is opposite the back surface. The row of sliders has segmented scribe lines which are discontinuous across the length of the row. Each slider may also have partial scribe lines, or simply a different pattern of scribe lines on the back surface. The present invention also includes a single slider with partial scribe lines which do not extend across the full width of the slider.
    Type: Grant
    Filed: November 10, 1998
    Date of Patent: August 22, 2000
    Assignee: International Business Machines Corporation
    Inventors: Linden James Crawforth, Chie Ching Poon, Andrew Ching Tam
  • Patent number: 6107599
    Abstract: Method and apparatus for laser texturing symmetrically and simultaneously both sides of a glass containing substrate, such as a magnetic disk. There are two or more acousto-optic modulators arranged in series to obtain equal laser pulses from a first beam from a laser, apparatus for capturing a first order diffracted beam from each acousto-optic modulator; monitoring the wavelength of the laser source, providing a visible indicator or diagnostic beam for each first order diffracted beam, and combining each first order diffracted beam with its respective indicator beam to form a texturing beam for texturing each side of the substrate.
    Type: Grant
    Filed: April 12, 1999
    Date of Patent: August 22, 2000
    Assignee: International Business Machines Corporation
    Inventors: Peter Baumgart, Chie Ching Poon, Andrew Ching Tam
  • Patent number: 6103990
    Abstract: Laser texturing apparatus includes an acousto-optical modulator which deflects a continuous laser beam into a first optical projection path to texture a first side of a disk or into a second optical projection path to texture a second side of the disk. The modulator causes lateral movement of the laser beam in a first direction as it is initially deflected into the first optical projection path and at the end of its deflection into this path. The modulator also caused lateral movement of the laser beam in a second direction as it is initially deflected into the second optical path and at the end of its deflection into this path. Each optical projection path is configured so that this lateral movement is in the direction of movement of the disk being textured at the spots at which it is textured.
    Type: Grant
    Filed: September 21, 1998
    Date of Patent: August 15, 2000
    Assignee: International Business Machines Corporation
    Inventors: Michael Barenboim, Pieter J. M. Kerstens, Hee Kuwon Park, Leonard S. Sheiner, Andrew Ching Tam
  • Patent number: 6075604
    Abstract: An apparatus for measuring a curvature of an air bearing surface (ABS) of a read/write magnetic head slider. The apparatus has two lasers which direct laser beams toward the ABS. The beams strike the ABS and are specularly reflected. The reflected beams are directed toward a position sensing optical detector. The distance between the points where the beams strike the detector is indicative of the curvature of the ABS. The beams my be alternately pulsed so that the detector outputs a DC-biased square wave signal, the voltage-step difference of which indicates the curvature. In another embodiment, a single laser beam is scanned by a scanner and passed through a scan lens. The scan lens is located one focal length from the scanner. A reflected laser beam is reflected from the ABS and is collected by the scan lens. The reflected laser beam is then directed toward a position sensing optical detector. The detector is located outside the focal plane of the scan lens.
    Type: Grant
    Filed: November 10, 1998
    Date of Patent: June 13, 2000
    Assignee: International Business Machines Corporation
    Inventors: Linden James Crawforth, Chie Ching Poon, Andrew Ching Tam
  • Patent number: 6059555
    Abstract: A disk texturing tool is used, for example, to provide textured spots in an annular portion of both sides of a hardfile disk. Disks are moved into and out of the texturing process in cassettes, through two disk-handling stations. An optical system includes a laser directed at a beamsplitter to split the laser beam into two beams having approximately equal power, which are directed along parallel paths through a power control optics block to expose simultaneously opposite sides of a disk to be textured. The power control optics block includes means for attenuating and measuring each of the two beams. A shuttling mirror directs these two beams alternately at a disk within each of the two disk handling stations.
    Type: Grant
    Filed: September 4, 1996
    Date of Patent: May 9, 2000
    Assignee: International Business Machines Corporation
    Inventors: Michael Barenboim, Peter Michael Baumgart, Peter B. Chrusch, Benny Michael Harper, Benjamin Karni, Pieter J. M. Kerstens, Doug John Krajnovich, Iraj Kahkesh Pour, Hong S. Seing, Andrew Ching Tam
  • Patent number: 6049056
    Abstract: A thin film conductive line is formed between MR pads on an MR head for protecting an MR sensor from electrostatic discharge (ESD) during assembly steps between row level fabrication of the head and prior to merge of a head stack assembly with a disk stack assembly. The conductive line may have a reduced thickness delete pad. A laser beam having a fluence sufficient to sever the conductive line at the delete pad but insufficient to damage or cause debris from structure underlying or surrounding the conductive line is used to sever the conductive line. The method traverses minimum energy, short laser pulses at a high pulse rate across the line, the melted material withdrawing from the melted area and being heaped on top of adjacent portions of the delete pad by surface tension and the melted material cooling to room temperature before the next pulse so that there is no cumulative heating and therefore no damage to or debris from the underlying structure.
    Type: Grant
    Filed: January 8, 1998
    Date of Patent: April 11, 2000
    Assignee: International Business Machines Corporation
    Inventors: Hamid Balamane, Chie Ching Poon, Neil Leslie Robertson, Andrew Ching Tam
  • Patent number: 6013336
    Abstract: A process for creating a "distant bump array" surface texture in a magnetic recording disk for reducing stiction and the disk so textured. The texturing process uses a tightly focused diode-pumped Nd:YLF or Nd:YVO.sub.4 or other solid-state laser that is pulsed with a 0.3-90 nanosecond pulse train to produce a plurality of distantly-spaced bumps in the disk surface. The bump creation process is highly controllable, permitting repeated creation of a preselected bump profile such as a smooth dimple or one with a central protrusion useful for low stiction without close spacing or elevated "roughness". Some bump profiles permit texturing of the data-storage region of the disk surface for low stiction without materially affecting magnetic data storage density.
    Type: Grant
    Filed: January 8, 1998
    Date of Patent: January 11, 2000
    Assignee: International Business Machines Corporation
    Inventors: Peter Michael Baumgart, Wing Pun Leung, Thao Anh Nguyen, Andrew Ching Tam
  • Patent number: 5981903
    Abstract: A laser system is described which concurrently directs highly equivalent diffracted beams derived from an initial laser beam to both sides of a substrate. The diffracted beams may be generated with sufficient energy to soften spots on the surfaces of the substrate to form texture bumps as are used on substrates for magnetic disks. The diffracted beams are generated by a multichannel acousto-optic modulator (MCAOM) having at least two channels. The crystal in the MCAOM has at least two mounting faces oriented so that the acoustic transducers mounted thereon generate acoustic fields which intersect the incident laser beam at a common angle, i.e., the Bragg angle. Energizing any of the transducers causes a corresponding first order beam to be diffracted out.
    Type: Grant
    Filed: March 28, 1997
    Date of Patent: November 9, 1999
    Assignee: International Business Machines Corporation
    Inventors: Peter Michael Baumgart, James Hammond Brannon, Chie Ching Poon, Iraj Kakesh Pour, Andrew Ching Tam
  • Patent number: 5963569
    Abstract: A multichannel acousto-optic modulator (MCAOM) is described which uses a crystal with a plurality of mounting faces for acoustic transducers. The mounting faces are oriented so that the acoustic transducers mounted thereon generate acoustic fields which intersect the incident laser beam at a common angle, i.e., the Bragg angle. A two channel MCAOM uses two transducers. Extension to any higher number of channels follows accordingly. Energizing any of the transducers causes a corresponding first order beam to be diffracted out. Since the acoustic field for each transducer intersects the incident beam with a unique orientation, each first order beam is diffracted out on a unique axis. A system utilizing an MCAOM has electronic means for controlling the driving signals to the transducers to control each channel as required by the application. Amplitude and frequency modulation of the driving signals allows the intensity and angle of the beams to be controlled.
    Type: Grant
    Filed: March 28, 1997
    Date of Patent: October 5, 1999
    Assignee: International Business Machines Corporation
    Inventors: Peter Michael Baumgart, James Hammond Brannon, Chie Ching Poon, Andrew Ching Tam
  • Patent number: 5951891
    Abstract: A disk texturing tool is used, for example, to provide textured spots in an annular portion of both sides of a hardfile disk. An optical system includes a laser directed at a beamsplitter to split the laser beam into two beams having approximately equal power, which are directed along parallel paths through a power control optics block to expose simultaneously opposite sides of a disk to be textured. A visible laser beam is also directed along this optical system to an inspection spot on each side of the disk, by which a central portion of each textured spots passes. A beam angle detector detects deflection of a reflection of the inspection beam from this spot in the direction of motion of the disk at this spot. This deflection provides a measure of the topography of the spot.
    Type: Grant
    Filed: March 24, 1997
    Date of Patent: September 14, 1999
    Assignee: International Business Machines Corporation
    Inventors: Michael Barenboim, Peter Michael Baumgart, Pieter J. M. Kerstens, Huizong Lu, Iraj Kahkesh Pour, Eric Von Schnetzer, Hong S. Seing, Andrew Ching Tam
  • Patent number: 5940304
    Abstract: A disk texturing tool is used, for example, to provide textured spots in an annular portion of both sides of a hardfile disk. Disks are moved into and out of the texturing process in cassettes, through two disk-handling stations. Control of the tool is achieved using a right-side disk handling and processing controller, a right-side cassette handling controller, a left-side disk handling and processing controller, and a left side cassette handling controller. The two disk handling and processing controllers share hardware resources performing the texturing process.
    Type: Grant
    Filed: September 4, 1996
    Date of Patent: August 17, 1999
    Assignee: International Business Machines Corporation
    Inventors: Michael Barenboim, Peter Michael Baumgart, Peter P. Chrusch, Benjamin Karni, Pieter J. M. Kerstens, Hong S. Seing, Andrew Ching Tam
  • Patent number: 5910262
    Abstract: Method and apparatus for laser texturing symmetrically and simultaneously both sides of a glass containing substrate, such as a magnetic disk. There are two or more acousto-optic modulators arranged in series to obtain equal laser pulses from a first beam from a laser, apparatus for capturing a first order diffracted beam from each acousto-optic modulator; monitoring the wavelength of the laser source, providing a visible indicator or diagnostic bean for each first order diffracted beam, and combining each first order diffracted beam with its respective indicator beam to form a texturing beam for texturing each side of the substrate.
    Type: Grant
    Filed: February 6, 1997
    Date of Patent: June 8, 1999
    Assignee: International Business Machines Corporation
    Inventors: Peter Baumgart, Chie Ching Poon, Andrew Ching Tam
  • Patent number: 5907144
    Abstract: The invention is a method and apparatus for imprinting a microscopic code on a small surface, such as the edge of a magnetic disk, or the head used to read or write information to the disk and a magnetic disk imprinted with such microscopic identification codes. The invention provides a way to identify products using microscopic codes, such as bar codes, by using a laser to imprint such microscopic bar codes on a product. The identification meets the stringent cleanliness requirements of the computer industry without generating debris, and so is exceptionally suited for use in identifying hard disks and heads used in a disk drive.
    Type: Grant
    Filed: February 5, 1997
    Date of Patent: May 25, 1999
    Assignee: International Business Machines Corporation
    Inventors: Chie Ching Poon, Clarence Jacob Spector, Andrew Ching Tam
  • Patent number: 5875084
    Abstract: A process for creating a "distant bump array" surface texture in a magnetic recording disk for reducing stiction and the disk so textured. The texturing process uses a tightly focused diode-pumped Nd:YLF or Nd:YVO.sub.4 or other solid-state laser that is pulsed with a 0.3-90 nanosecond pulse train to produce a plurality of distantly-spaced bumps in the disk surface. The bump creation process is highly controllable, permitting repeated creation of a preselected bump profile such as a smooth dimple or one with a central protrusion useful for low stiction without close spacing or elevated "roughness". Some bump profiles permit texturing of the data-storage region of the disk surface for low stiction without materially affecting magnetic data storage density.
    Type: Grant
    Filed: July 8, 1997
    Date of Patent: February 23, 1999
    Assignee: International Business Machines Corporation
    Inventors: Peter Michael Baumgart, Wing Pun Leung, Thao Anh Nguyen, Andrew Ching Tam
  • Patent number: 5830514
    Abstract: A disk texturing tool is used, for example, to provide textured spots in an annular portion of both sides of a hardfile disk. Disks are moved into and out of the texturing process in cassettes, through two disk-handling stations. Texturing occurs as the annular portions are exposed to a train of pulses from a Q-switched laser. The Q-switch within the laser is driven by a radio-frequency signal form an oscillator, which is in turn driven by a signal from a pulse generator, which can be adjusted to leave the radio-frequency signal on for a variable time between pulses without changing pulse frequency. The laser may be equipped with a shutter and with an electronic gate selectively preventing the production of laser pulses.
    Type: Grant
    Filed: September 4, 1996
    Date of Patent: November 3, 1998
    Assignee: International Business Machines Corporation
    Inventors: Michael Barenboim, Peter Michael Baumgart, Peter P. Chrusch, Benjamin Karni, Pieter J. M. Kerstens, Hong S. Seing, Andrew Ching Tam
  • Patent number: 5822211
    Abstract: A disk texturing process uses a single pulsed laser to texture disks within a first group, which are carried through the texturing process on a first spindle assembly, and from a second group, which are carried through the texturing process on a second spindle assembly. Preferably, disks from the first group are textured alternately with disks in the second group. A first level of least one texturing parameter is stored for use only as the process is applied to disks from the first group, while a second level of the same texturing parameter is stored for use only as the process is applied to disks from the second group. These levels may be derived from measurements of textured spots made with interferometric devices forming portions of a texturing station.
    Type: Grant
    Filed: November 13, 1996
    Date of Patent: October 13, 1998
    Assignee: International Business Machines Corporation
    Inventors: Michael Barenboim, Peter Michael Baumgart, Peter P. Chrusch, Benny Michael Harper, Benjamin Kami, Pieter J. M. Kerstens, Michael Gerard Lisanke, Huizong Lu, Lanphuong Thi Pena, Eric V. Schnetzer, Hong S. Seing, Ali Reza Taheri, Andrew Ching Tam
  • Patent number: 5790433
    Abstract: A disk texturing tool is used, for example, to provide textured spots in an annular portion of both sides of a disk for a hard disk drive. Disks are moved into and out of the texturing process in cassettes, through two disk-handling stations. An optical system includes a laser directed at a beamsplitter to split the laser beam into two beams having approximately power, which are directed along parallel paths through a power control optics block to expose simultaneously opposite sides of a disk to be textured. The power level of each of these two beams is controlled by a program which operates in a teach mode to develop a look up table describing laser beam power as a function of a signal driving an attenuator, in a set point mode setting this drive signal to provide a certain laser beam power, in a run mode controlling this power through a feedback loop, and in a display mode showing laser beam power as a function of time.
    Type: Grant
    Filed: September 5, 1996
    Date of Patent: August 4, 1998
    Assignee: International Business Machines Corporation
    Inventors: Michael Barenboim, Peter Michael Baumgart, Peter P. Chrusch, Benny Michael Harper, Benjamin Karni, Pieter J. M. Kerstens, Hong S. Seing, Andrew Ching Tam
  • Patent number: 5768076
    Abstract: A data recording disk having at least part of the data storage surface textured according to a process for creating a "distant bump array" surface texture for reducing stiction. The texturing process uses a tightly focused diode-pumped Nd:YLF or Nd:YVO.sub.4 or other solid-state laser that is pulsed with a 0.3-90 nanosecond pulse train to produce a plurality of distantly-spaced bumps in the disk surface. The bump profile can be selected as a smooth dimple or one with a central protrusion useful for low stiction without close spacing or elevated "roughness". The data-storage region of the disk surface can be textured for low stiction without materially affecting magnetic data storage density.
    Type: Grant
    Filed: February 15, 1996
    Date of Patent: June 16, 1998
    Assignee: International Business Machines Corporation
    Inventors: Peter Michael Baumgart, Wing Pun Leung, Thao Anh Nguyen, Andrew Ching Tam
  • Patent number: 5761005
    Abstract: A disk drive assembly in which the suspension, slider and transducer are integrated and fabricated to produce a combination assembly. The combination transducer-slider-suspension assembly is batch produced by forming a plurality of the combination assemblies onto a single wafer. The wafer is then diced to separate the assemblies into individual sections. The transducers are deposited onto the wafer and the air bearing surface formed. Conductors to interconnect each transducer with the external circuits are insulated from the wafer and deposited along a path which will form the suspension. A spring-like resilient layer is then deposited over and electrically insulated from the conductors. The wafer is then pattern etched to remove a portion of the wafer backside to form the suspension and provide a transducer/slider combination having an air bearing surface after the wafer is diced to separate the individual combination assemblies.
    Type: Grant
    Filed: September 10, 1997
    Date of Patent: June 2, 1998
    Assignee: International Business Machines Corporation
    Inventors: Jeffrey Merritt McKay, Henry Shusei Nishihira, Andrew Ching Tam
  • Patent number: 5759428
    Abstract: A thin film conductive line is formed between MR pads on an MR head for protecting an MR sensor from electrostatic discharge (ESD) during assembly steps between row level fabrication of the head and prior to merge of a head stack assembly with a disk stack assembly. The conductive line may have a reduced thickness delete pad. A laser beam having a fluence sufficient to sever the conductive line at the delete pad but insufficient to damage or cause debris from structure underlying or surrounding the conductive line is used to sever the conductive line.
    Type: Grant
    Filed: March 15, 1996
    Date of Patent: June 2, 1998
    Assignee: International Business Machines Corporation
    Inventors: Hamid Balamane, Chie Ching Poon, Neil Leslie Robertson, Andrew Ching Tam