Patents by Inventor Kwong-Tat Chan

Kwong-Tat Chan 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: 7423831
    Abstract: A method for writing servo information onto a disk of a hard disk drive with a servo writer. The method includes accelerating a head to a constant velocity across a disk. The disk being defined as having an acceleration zone and a constant velocity zone. The head is then used to write a spiral servo pattern in the constant velocity zone. A final servo pattern is written in the constant velocity zone using the spiral servo pattern. A servo reference pattern is also written in the acceleration zone. The servo reference pattern is used to write a final servo pattern in the acceleration zone. The final servo pattern may be copied using a run-out cancellation algorithm to improve the accuracy of the servo pattern in the acceleration zone.
    Type: Grant
    Filed: October 17, 2006
    Date of Patent: September 9, 2008
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Bipinchandra V. Gami, Yih Hurng Jung, Hao Ping Wen, Kwong-Tat Chan
  • Publication number: 20080170323
    Abstract: A method for writing servo information onto a disk of a hard disk drive with a servo writer. The method includes accelerating a head to a constant velocity across a disk. The disk being defined as having an acceleration zone and a constant velocity zone. The head is then used to write a spiral servo pattern in the constant velocity zone. A final servo pattern is written in the constant velocity zone using the spiral servo pattern. A servo reference pattern is also written in the acceleration zone. The servo reference pattern is used to write a final servo pattern in the acceleration zone. The final servo pattern may be copied using a run-out cancellation algorithm to improve the accuracy of the servo pattern in the acceleration zone.
    Type: Application
    Filed: October 17, 2006
    Publication date: July 17, 2008
    Inventors: Bipinchandra V. Gami, Yih Hurng Jung, Hao Ping Wen, Kwong-Tat Chan
  • Patent number: 7253985
    Abstract: A method for writing servo information onto a disk of a hard disk drive with a servo writer. The disk has a circumferential index and a band of servo reference tracks. The circumferential index is detected from a clock signal generated from a clock track of the disk. The reference tracks include radial indices. A spiral servo pattern is written upon the detection of the circumferential index and a radial index. The servo writer includes a phase detector that detects changes in the relative position of the circumferential and radial indices and a delay circuit that delays the clock signal to offset such changes.
    Type: Grant
    Filed: March 6, 2006
    Date of Patent: August 7, 2007
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Bipinchandra V. Gami, Joe Bragg, Nikolay Ivanov, Linh Nguyen, Kwong Tat Chan
  • Patent number: 7190545
    Abstract: A method for writing servo information onto a disk of a hard disk drive. The method includes writing a reference servo pattern onto a track of a disk with an off-line servo track writer. The reference servo pattern has less servo bits than the final pattern allowing the off-line writer to write in a single pass. The disk is then assembled into a hard disk drive assembly and a final servo pattern is written onto the track. The final pattern can also be written with two passes. The single pass writing process reduces the time required to write the servo information. Additionally, the off-line servo track writer can write servo on a plurality of disk at the same time, further reducing the process time for writing servo and mass producing hard disk drives.
    Type: Grant
    Filed: February 5, 2004
    Date of Patent: March 13, 2007
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Kwong Tat Chan, Nikolay Ivanov
  • Patent number: 7158336
    Abstract: A method for writing servo information onto a disk of a hard disk drive with a servo writer. The method includes writing a plurality of spiral servo signals with a head. The spiral servo signals are used to write servo patterns using at least one timing window. The timing window is adjusted using a position error signal generated from the spiral servo signals. The adjusted timing window is then used to write servo patterns onto the disk. Adjusting the timing window compensates for irregularities in the spiral servo signals.
    Type: Grant
    Filed: February 2, 2005
    Date of Patent: January 2, 2007
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Kwong-Tat Chan, Tom Chan, Bipinchandra V. Gami, Tung Nguyen, Yih Hurng Jung
  • Publication number: 20060171059
    Abstract: A method for writing servo information onto a disk of a hard disk drive with a servo writer. The method includes writing a plurality of spiral servo signals with a head. The spiral servo signals are used to write servo patterns using at least one timing window. The timing window is adjusted using a position error signal generated from the spiral servo signals. The adjusted timing window is then used to write servo patterns onto the disk. Adjusting the timing window compensates for irregularities in the spiral servo signals.
    Type: Application
    Filed: February 2, 2005
    Publication date: August 3, 2006
    Inventors: Kwong-Tat Chan, Tom Chan, Bipinchandra Gami, Tung Nguyen, Yih Jung
  • Publication number: 20060171058
    Abstract: a method for writing servo information onto a disk of a hard disk drive with a servo writer. The method includes writing a reference servo pattern onto a track of a disk. A head is then positioned relative to the reference servo pattern and a spiral servo track is written onto the disk. The process of positioning the head relative to the reference servo pattern and writing a spiral servo track can be repeated to create a plurality of spiral servo tracks on the disk. The spiral tracks are used to write radial servo patterns that are utilized during normal operation of the drive. The reference servo pattern allows each spiral track to start at a point with the same radial distance from the center of the disk. This improves the accuracy of the spiral tracks and the resultant final servo patterns.
    Type: Application
    Filed: February 2, 2005
    Publication date: August 3, 2006
    Inventors: Kwong-Tat Chan, Bipinchandra Gami, Nikolay Ivanov