Patents by Inventor Xiaofeng Zhang

Xiaofeng Zhang 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: 7085083
    Abstract: A system and method for testing the stroke and frequency response of a micro-actuator is disclosed. A dynamic parameter tester writes two concentric tracks on a noise free portion of a magnetic storage medium. A magnetic read/write head and a micro-actuator is positioned between the two concentric tracks. An initial oscillating voltage is applied at a first frequency to the micro-actuator while reading back a signal from the two concentric tracks. A stroke characteristic of the micro-actuator is calculated based in part on the read-back signal. The initial oscillating voltage is determined from previous tests. The first stroke characteristic of the micro-actuator is based on a time-averaged amplitude of the first signal. The two concentric tracks are written at a pre-determined pitch.
    Type: Grant
    Filed: December 5, 2003
    Date of Patent: August 1, 2006
    Assignee: SAE Magnetics (H.K.) Ltd.
    Inventors: Li-Yan Zhu, Chao-Hui Yang, Xiaofeng Zhang, Yen Fu, Ellis T. Cha
  • Patent number: 6989671
    Abstract: A method is described for calculating head disk interference (HDI) using a dynamic parametric test. In one embodiment, HDI is calculated based on an actual and ideal sensitivity profile based on a read-back signal track profile for the slider/head.
    Type: Grant
    Filed: January 14, 2003
    Date of Patent: January 24, 2006
    Assignee: SAE Magnetics (H.K.) Ltd.
    Inventors: Li-Yan Zhu, Xiaofeng Zhang, Yen Fu, Ellis T. Cha
  • Publication number: 20050174667
    Abstract: A system and method for measuring the modulation between a magnetic head and a magnetic storage medium, such as a disk, is disclosed. A magnetic read/write head is positioned above a magnetic storage medium at a given flying height. The magnetic read/write head reads a signal from the magnetic storage medium. A tester measures an alternating electric current between the magnetic read/write head through the slider and the magnetic storage medium. A computer may then calculate the modulation by the magnetic read/write head based on the alternating electric current. A DC voltage to the head may be applied to lower the flying height of the magnetic head.
    Type: Application
    Filed: November 4, 2004
    Publication date: August 11, 2005
    Inventors: Zhu Feng, Xiaofeng Zhang, Ellis Cha
  • Publication number: 20050174665
    Abstract: According to an embodiment of the present invention, head/disk contact events are determined through a measurement of current at the head disk interface. For example, an ammeter/voltage source component may be electrically coupled to a magnetic/slider of a disk drive as well as to a spindle coupled to the recording medium. Applied voltage to the slider may result in a lower flying height. Greater measured current by the ammeter could indicate head/disk contact and assist in adjusting applied voltage to obtain a desire flying height.
    Type: Application
    Filed: February 9, 2004
    Publication date: August 11, 2005
    Inventors: Xiaofeng Zhang, Zhu Feng, Ellis Cha, Yen Fu
  • Publication number: 20050122607
    Abstract: A system and method for testing the stroke and frequency response of a micro-actuator is disclosed. A dynamic parameter tester writes two concentric tracks on a noise free portion of a magnetic storage medium. A magnetic read/write head and a micro-actuator is positioned between the two concentric tracks. An initial oscillating voltage is applied at a first frequency to the micro-actuator while reading back a signal from the two concentric tracks. A stroke characteristic of the micro-actuator is calculated based in part on the read-back signal. The initial oscillating voltage is determined from previous tests. The first stroke characteristic of the micro-actuator is based on a time-averaged amplitude of the first signal. The two concentric tracks are written at a pre-determined pitch.
    Type: Application
    Filed: December 5, 2003
    Publication date: June 9, 2005
    Inventors: Li-Yan Zhu, Chao-Hui Yang, Xiaofeng Zhang, Yen Fu, Ellis Cha
  • Publication number: 20040223262
    Abstract: A system and method for measuring and neutralizing the electrical charge at the interface of a magnetic head and a magnetic storage medium, such as a disk, is disclosed. A surface treatment material is applied to the magnetic head. The surface treatment material matches the medium surface material on the surface of the magnetic storage medium. The surface treatment material on the magnetic read/write head may be a fluorinated carbon, such as a Fomblin Z-derivative, perfluoro alkyl trichlorosilane, a FC-722, or a fluorinated polymer. The surface treatment material can be applied to the magnetic head by a vapor deposition process or by a liquid immersion process. The charge on the head-disk interface can be measured by applying varying external charges to the head while reading a signal previously written to the disk.
    Type: Application
    Filed: May 7, 2003
    Publication date: November 11, 2004
    Inventors: Zhu Feng, Ellis Cha, Xiaofeng Zhang
  • Publication number: 20040135575
    Abstract: A method is described for calculating head disk interference (HDI) using a dynamic parametric test. In one embodiment, HDI is calculated based on an actual and ideal sensitivity profile based on a read-back signal track profile for the slider/head.
    Type: Application
    Filed: January 14, 2003
    Publication date: July 15, 2004
    Inventors: Li-Yan Zhu, Xiaofeng Zhang, Yen Fu, Ellis T. Cha
  • Publication number: 20030118671
    Abstract: The present invention relates to a pharmaceutical preparation of natural plants. More particularly, the present invention relates to a preparation containing leaf extract of Arachis hypogaea and process for making the same.
    Type: Application
    Filed: October 2, 2002
    Publication date: June 26, 2003
    Inventors: Qiaochu Wang, Chuanyu Pang, Shangiian Du, Ming Shi, Jian Xu, Xiaofeng Zhang