Patents by Inventor Chengwu An

Chengwu An 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).

  • Publication number: 20130093419
    Abstract: An apparatus and method of testing a magnetic medium at temperatures of interest is disclosed. Properties of the magnetic medium are determined by focusing light from a source of polarized light on a magnetic surface of the magnetic medium; measuring polarization of resulting reflected light due to the magneto-optical Kerr effect, using, for example a measuring subsystem; and varying the light source to heat the magnetic material where incident to pre-defined temperatures, thereby allowing determination of the magnetic properties using the magneto-optical Kerr effect at said pre-defined temperatures.
    Type: Application
    Filed: June 13, 2011
    Publication date: April 18, 2013
    Applicant: AGENCY FOR SCIENCE, TECHNOLOGY AND RESEARCH
    Inventors: Chengwu An, Kaidong Ye, Qiong Xie, Wendong Song, Kay Siang Tiaw
  • Patent number: 8283622
    Abstract: A method and apparatus for testing a magnetic medium. The method comprises applying a magnetic field of a time-varying strength; directing a polarized optical beam towards a portion of the medium that is in the magnetic field, wherein the optical beam is reflected by a surface of the medium at a point of incidence in the magnetic field; moving the medium relative to the optical beam so as to cause the point of incidence to repeatedly traverse each of a plurality of sectors along a track on the surface; obtaining a series of Kerr signal measurements of the reflected optical beam; grouping measurements into ensembles such that the measurements in an individual ensemble are those obtained while the point of incidence was in a corresponding one of the sectors; and determining at least one magnetic property of at least one of the sectors from the measurements in the corresponding ensemble.
    Type: Grant
    Filed: August 13, 2008
    Date of Patent: October 9, 2012
    Assignee: Agency for Science, Technology and Research
    Inventors: Chengwu An, Kaidong Ye
  • Publication number: 20110310387
    Abstract: A method and apparatus for testing a magnetic medium. The method comprises applying a magnetic field of a time-varying strength; directing a polarized optical beam towards a portion of the medium that is in the magnetic field, wherein the optical beam is reflected by a surface of the medium at a point of incidence in the magnetic field; moving the medium relative to the optical beam so as to cause the point of incidence to repeatedly traverse each of a plurality of sectors along a track on the surface; obtaining a series of Kerr signal measurements of the reflected optical beam; grouping measurements into ensembles such that the measurements in an individual ensemble are those obtained while the point of incidence was in a corresponding one of the sectors; and determining at least one magnetic property of at least one of the sectors from the measurements in the corresponding ensemble.
    Type: Application
    Filed: August 13, 2008
    Publication date: December 22, 2011
    Applicant: Agency for Science, Technology and Research
    Inventors: Chengwu An, Kaidong Ye
  • Patent number: 7170029
    Abstract: This invention relates to a method and apparatus for deflashing integrated circuit (IC) packages by laser irradiation. The method and apparatus include two lasers scanning flash area for performing deflashing operation. CO2 laser is used to remove top layer of flash and YAG laser is used to remove the thin layer of flash remained after CO2 laser deflashing. CO2 laser deflashing and following YAG laser deflashing can effectively remove flash and avoid damage of heat sinks as well as leads and bars in the IC packages.
    Type: Grant
    Filed: July 29, 2004
    Date of Patent: January 30, 2007
    Assignee: Data Storage Institute
    Inventors: Wen Dong Song, Minghui Hong, Chengwu An, Yong Feng Lu
  • Publication number: 20050082266
    Abstract: This invention relates to a method and apparatus for deflashing integrated circuit (IC) packages by laser irradiation. The method and apparatus include two lasers scanning flash area for performing deflashing operation. CO2 laser is used to remove top layer of flash and YAG laser is used to remove the thin layer of flash remained after CO2 laser deflashing. CO2 laser deflashing and following YAG laser deflashing can effectively remove flash and avoid damage of heat sinks as well as leads and bars in the IC packages.
    Type: Application
    Filed: July 29, 2004
    Publication date: April 21, 2005
    Applicant: Data Storage Institute
    Inventors: Wen Song, Minghui Hong, Chengwu An, Yong Lu
  • Patent number: 6838637
    Abstract: This invention relates to a method and apparatus for deflashing integrated circuit (IC) packages by laser irradiation. The method and apparatus include two lasers scanning flash area for performing deflashing operation. CO2 laser is used to remove top layer of flash and YAG laser is used to remove the thin layer of flash remained after CO2 laser deflashing. CO2 laser deflashing and following YAG laser deflashing can effectively remove flash and avoid damage of heat sinks as well as leads and bars in the IC packages.
    Type: Grant
    Filed: January 29, 2002
    Date of Patent: January 4, 2005
    Assignee: Data Storage Institute
    Inventors: Wen Dong Song, Minghui Hong, Chengwu An, Yong Feng Lu
  • Publication number: 20040124184
    Abstract: A method and apparatus for directly forming periodic structures on a substrate by laser irradiation comprises directing a linearly polarized laser beam onto a first location of the substrate; irradiating the substrate for a sustained duration using the linearly polarized laser beam for melting the substrate at the first location to induce a surface wave thereon; the melted substrate having a plurality of ridges corresponding to the wavelengths of the surface wave. The linearly polarized laser beam scans the substrate along a first path to propagate the surface wave on the substrate; and thereafter, substrate is cooled down following scanning of the linearly polarized laser for solidifying the plurality of ridges to form a first group of periodic structure on the substrate. Periodic structures formed according to the invention may be optical gratings such as diffraction or reflective gratings.
    Type: Application
    Filed: June 12, 2003
    Publication date: July 1, 2004
    Inventors: Chengwu An, Dongjiang Wu, Weijie Wang, Minghui Hong
  • Patent number: 6753500
    Abstract: The invention relates to a method and apparatus for cutting a substrate using laser irradiation. A laser beam is scanned over a substrate. The beam ablates a first layer of the substrate. The beam is then refocused onto the newly revealed second layer and a further pass is performed. The process is repeated until complete separation occurs. The method and apparatus are particularly suitable for singulation of IC packages.
    Type: Grant
    Filed: February 19, 2002
    Date of Patent: June 22, 2004
    Assignee: Data Storage Institute
    Inventors: Kaidong Ye, Chengwu An, Minghui Hong, Yongfeng Lu
  • Publication number: 20030155333
    Abstract: The invention relates to a method and apparatus for cutting a substrate using laser irradiation. A laser beam is scanned over a substrate. The beam ablates a first layer of the substrate. The beam is then refocused onto the newly revealed second layer and a further pass is performed. The process is repeated until complete separation occurs. The method and apparatus are particularly suitable for singulation of IC packages.
    Type: Application
    Filed: February 19, 2002
    Publication date: August 21, 2003
    Inventors: Kaidong Ye, Chengwu An, Minghui Hong, Yongfeng Lu
  • Publication number: 20030062347
    Abstract: This invention relates to a method and apparatus for deflashing integrated circuit (IC) packages by laser irradiation. The method and apparatus include two lasers scanning flash area for performing deflashing operation. CO2 laser is used to remove top layer of flash and YAG laser is used to remove the thin layer of flash remained after CO2 laser deflashing. CO2 laser deflashing and following YAG laser deflashing can effectively remove flash and avoid damage of heat sinks as well as leads and bars in the IC packages.
    Type: Application
    Filed: January 29, 2002
    Publication date: April 3, 2003
    Applicant: Data Storage Institute
    Inventors: Wen Dong Song, Minghui Hong, Chengwu An, Yong Feng Lu
  • Publication number: 20030006221
    Abstract: A method and apparatus are provided for cutting a substrate using dual laser irradiation. Two lasers are provided, one focussed on a first substrate layer and one on a second layer so as to ablate the said layers. The wavelength and other parameters of the lasers are selected so as to correspond with the layer material to be ablated. The invention is particularly suitable for the singulation of IC packages.
    Type: Application
    Filed: January 17, 2002
    Publication date: January 9, 2003
    Inventors: Minghui Hong, Kaidong Ye, Chengwu An, Da Ming Liu
  • Publication number: 20030001457
    Abstract: In a flat panel display, a laser spacer array is created on the transparent substrate 10′ to maintain the two substrates at a pre-determined spacing in the finished panel. The spacers 20 are distributed between the two substrates, which are sealed using sealant 18 resulting in a cell gap with pre-determined spacing distance.
    Type: Application
    Filed: September 19, 2001
    Publication date: January 2, 2003
    Applicant: DATA STORAGE INSTITUTE
    Inventors: Weijie Wang, Minghui Hong, Chengwu An, Yong Feng Lu