Patents by Inventor Francis Liu

Francis Liu 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: 7113366
    Abstract: A thin film electromagnetic head has an inductive transducer with a double-nosed ferromagnetic trailing pole layer. The trailing pole layer has a trailing pole tip disposed adjacent to a media-facing surface, a trailing pole yoke disposed distal to the media-facing surface, and a trailing pole nose disposed between the trailing pole tip and the trailing pole yoke. The media-facing surface extends as a substantially flat surface in all directions from the trailing pole tip. The length of the trailing pole nose may be at least twice as long as the trailing pole tip length. The width of the trailing pole nose can be 10 to 30 times as wide as the trailing pole tip width. An inductive transducer having a double-nosed trailing pole layer provides a higher ratio of on-track to off-track write fields, thereby improving the density with which data can be written to the recording media. Such a double-nosed trailing pole layer can be used in transducers for either longitudinal or perpendicular magnetic recording.
    Type: Grant
    Filed: November 7, 2002
    Date of Patent: September 26, 2006
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Yugang Wang, Kroum Stoev, Francis Liu, Yingjian Chen
  • Patent number: 6989972
    Abstract: Magnetoresistive (MR) sensors have leads that overlap a MR structure and distribute current to the MR structure so that the current is not concentrated in small portions of the leads. An electrically resistive capping layer can be formed between the leads and the MR structure to distribute the current. The leads can include resistive layers and conductive layers, the resistive layers having a thickness-to-resistivity ratio that is greater than that of each of the conductive layers. The resistive layers may protect the conductive layers during MR structure etching, so that the leads have broad layers of electrically conductive material for connection to MR structures. The broad leads conduct heat better than the read gap material that they replace, further reducing the temperature at the connection between the leads and the MR structure.
    Type: Grant
    Filed: September 30, 2002
    Date of Patent: January 24, 2006
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Kroum Stoev, Mathew Gibbons, Francis Liu, Bogdan M. Simion, Aparna C. Vadde, Jing Zhang, Yiming Huai, Marcos M. Lederman
  • Patent number: 6912106
    Abstract: A method and system for providing a recording head is disclosed. The method and system include providing a first pole, a second pole, a write gap and at least one coil. The write cap separates the first pole from the second pole. The coil(s) include a plurality of turns and is between the first and second poles. The first pole includes a pedestal that has a first portion and a second portion. The first portion includes a high moment electroplated material. The second portion includes a hot seed layer that has a high moment sputtered material. The second portion of the first pole is adjacent to the write gap.
    Type: Grant
    Filed: August 6, 2002
    Date of Patent: June 28, 2005
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Yingjian Chen, Qing He, Yugang Wang, Kroum Stoev, Francis Liu, Xiaozhong Dang
  • Publication number: 20050007696
    Abstract: A read/write head and method of making the same are used in a data storage system, such as a disk drive, for perpendicular magnetic recording of data. The head employs a two-layer pole design with a main pole made of sputtered high moment magnetic material, and an adjunct pole made of electroplated soft magnetic film. The main pole is used to write data onto the medium, and is formed over the write coil. The adjunct pole is substantially recessed from the air bearing surface and is formed over the main pole. The present head design significantly enhances the magnetic write field, and substantially reduces side-writing that result in accidental erasure of data in adjacent tracks on the magnetic recording medium.
    Type: Application
    Filed: July 29, 2004
    Publication date: January 13, 2005
    Applicant: Western Digital (Fremont), Inc.
    Inventors: Yingjian Chen, Xiaozhong Dang, Francis Liu, Kroum Stoev, Hai Jiang, Yugang Wang, Xizeng Shi
  • Patent number: 6809899
    Abstract: Electromagnetic transducers are disclosed having write poles with a leading edge that is smaller than a trailing edge, which can reduce erroneous writing for perpendicular recording systems. The write poles may have a trapezoidal shape when viewed from a direction of an associated medium. The write poles may be incorporated in heads or sliders that also contain read elements such as magnetoresistive sensors, and may be employed with information storage systems such as disk drives.
    Type: Grant
    Filed: December 31, 2003
    Date of Patent: October 26, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Yingjian Chen, Yugang Wang, Francis Liu, Xizeng Shi, Kyusik Sin, Hugh Craig Hiner
  • Patent number: 6724572
    Abstract: In one aspect, an inductive transducer is disclosed having a leading pole layer and a leading pole tip, with the pole layer being further removed than the pole tip from a media-facing surface. In another aspect, an inductive transducer is disclosed having a magnetic pedestal disposed between a leading pole layer and a leading pole tip, with at least one of the pedestal and pole layer being further removed than the pole tip from a media-facing surface. In another aspect, a leading pole layer or pedestal may have a surface that slopes away from the media-facing surface with increasing distance forward from the leading pole tip.
    Type: Grant
    Filed: February 28, 2002
    Date of Patent: April 20, 2004
    Assignee: Western Digital, Inc.
    Inventors: Kroum Stoev, Yugang Wang, Francis Liu, Yingjian Chen, Xiaozhong Dang
  • Patent number: 6721138
    Abstract: An inductive transducer having first and second magnetic pedestals disposed between first and second magnetic pole layers and adjacent to a media-facing surface, the pedestals separated by a submicron, nonmagnetic gap. The first pedestal extends less than the second pedestal from the media-facing surface, defining a short throat height. The second pedestal extends further to provide sufficient area for stitching to the second pole layer. The stitching and the thickness provided by the pedestals allow plural coil layers to be disposed between the pole layers, and the second pedestal, as well as other features, can be defined by high-resolution photolithography. The two coil layers have lower resistance, lower inductance and allow the pole layers to be shorter, improving performance. All or part of either or both of the pedestals may be formed of high magnetic saturation material, further enhancing performance.
    Type: Grant
    Filed: October 24, 2001
    Date of Patent: April 13, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Yingjian Chen, Xizeng Shi, Hugh Craig Hiner, Zi-Wen Dong, Francis Liu, Matthew R. Gibbons, Joyce Anne Thompson, William D. Jensen, Chester Xiaowen Chien, Yugang Wang
  • Patent number: 6468436
    Abstract: A system and method for providing a head for reading data is disclosed. The method and system include providing a magnetoresistive element and providing a flux guide having a high resistivity. The magnetoresistive element has an end. The flux guide also has an end. The end of the flux guide is adjacent to the end of the magnetoresistive element.
    Type: Grant
    Filed: July 12, 2000
    Date of Patent: October 22, 2002
    Assignee: Read-Rite Corporation
    Inventors: Xizeng Shi, Hua-Ching Tong, Ming Zhao, Francis Liu
  • Patent number: 6137661
    Abstract: A system and method for providing a head for reading data is disclosed. The method and system include providing a magnetoresistive element and providing a flux guide having a high resistivity. The magnetoresistive element has an end. The flux guide also has an end. The end of the flux guide is adjacent to the end of the magnetoresistive element.
    Type: Grant
    Filed: October 19, 1998
    Date of Patent: October 24, 2000
    Assignee: Read-Rite Corporation
    Inventors: Xizeng Shi, Hua-Ching Tong, Ming Zhao, Francis Liu