Patents by Inventor Helen Lai Wa Chan-Wong

Helen Lai Wa Chan-Wong 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: 7462960
    Abstract: An ultrasonic transducer driver has a giant magnetostrictive element, a fastener for holding the giant magnetostrictive element under mechanical pressure, a first field generator for providing a magnetic bias field, a second field generator for providing a magnetic drive field and a magnetic circuit for channelling the magnetic fields in the magnetostrictive element. An ultrasonic transducer for a bonding apparatus has a horn having a bonding tool at its smaller end and a mounting barrel adjoined onto it. The driver coupled to the larger end of the horn.
    Type: Grant
    Filed: January 5, 2004
    Date of Patent: December 9, 2008
    Assignee: The Hong Kong Polytechnic University
    Inventors: Siu Wing Or, Chung Sheung Yung, Helen Lai Wa Chan-Wong
  • Patent number: 7298060
    Abstract: The operational frequency of existing magnetoelectric materials having metallic or ceramic magnetostrictive materials and ceramic piezoelectric materials may be limited to a few kilohertz due to the presence of eddy-current losses in the metallic magnetostrictive phase. Further, these materials may be difficult to machine and fabricate due to their brittleness. Additionally, it may be difficult to tailor and optimize the properties (i.e., magnetoelectric voltage coefficient ?E, etc.) of the devices. This invention provides a magnetoelectric element including at least one set of alternating piezoelectric layers and magnetostrictive composite layers. The magnetostrictive composite layer includes at least one magnetostrictive material dispersed in first concentrated zones within a first polymer matrix, wherein all of the concentrated zones are orientated along a first direction. It is found that the conversion efficiency (i.e., ?E) varies in accordance with applied magnetic control field Hcontrol.
    Type: Grant
    Filed: February 21, 2007
    Date of Patent: November 20, 2007
    Assignee: The Hong Kong Polytechnic University
    Inventors: Siu Wing Or, Helen Lai Wa Chan-Wong
  • Patent number: 7199495
    Abstract: The operational frequency of existing magnetoelectric materials having metallic or ceramic magnetostrictive materials and ceramic piezoelectric materials may be limited to a few kilohertz due to the presence of eddy-current losses in the metallic magnetostrictive phase. Further, these materials may be difficult to machine and fabricate due to their brittleness. Additionally, it may be difficult to tailor and optimize the properties (i.e., magnetoelectric voltage coefficient ?E, etc.) of the devices. This invention provides a magnetoelectric element including at least one set of alternative piezoelectric layer and magnetostrictive composite layer. The magnetostrictive composite layer includes at least one magnetostrictive material dispersed in first concentrated zones within a first polymer matrix, wherein all of said concentrated zones are orientated along a first direction. It is found that the conversion efficiency (i.e., ?E) varies in accordance with applied magnetic control field Hcontrol.
    Type: Grant
    Filed: April 1, 2004
    Date of Patent: April 3, 2007
    Assignee: The Hong Kong Polytechnic University
    Inventors: Siu Wing Or, Helen Lai Wa Chan-Wong