Patents by Inventor Kin Wing Kwok

Kin Wing Kwok 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: 7819013
    Abstract: An apparatus and method for detecting the oscillation amplitude of a bonding tool includes a sensing unit disposed adjacent to and at a distance from the bonding tool. The sensing unit includes a pair of electrodes, a piezoelectric sensing layer located between the pair of electrodes, and a membrane associated with the piezoelectric sensing layer. The piezoelectric sensing layer becomes sensitive to ultrasonic vibrations and generates electrical voltage signals after being activated by a poling process. An optional pre-amplifier is used to amplify the signals generated from the sensing unit, and an oscilloscope is used to further process the signals.
    Type: Grant
    Filed: July 5, 2006
    Date of Patent: October 26, 2010
    Assignee: The Hong Kong Polytechnic University
    Inventors: Helen Lai Wa Chan, Tin Yan Lam, Chen Chao, Kin Wing Kwok
  • Patent number: 7494601
    Abstract: The present invention provides a piezoelectric ceramic composition, especially a lead-free piezoelectric ceramic composition, with a suitable amount of CeO2 or CeO2-containing complex additives, which is represented by the following formula: (Na0.475K0.475Li0.05)(Nb1-xAx)O3+yCeO2+zBO2 wherein “A” represents Sb or Sb+Ta, “B” represents a tetravalent transition metal, 0?x?0.2, 0.2 wt %<y<1.2 wt % and 0?z 1 wt %. Addition of CeO2 or CeO2-containing complex additives suppresses melting and abnormal grain growth of (Na0.475K0.475Li0.05)(Nb1-xAx)O3 during sintering, thereby improving sinterability and increasing the density of the composition. As a result, the dielectric and piezoelectric properties of the ceramics are enhanced. Furthermore, the represented compositions have a wide sintering temperature range so that the process for preparing such a lead-free piezoelectric ceramic composition has high degree efficiency.
    Type: Grant
    Filed: February 28, 2006
    Date of Patent: February 24, 2009
    Assignee: The Hong Kong Polytechnic University
    Inventors: Xiaoxing Wang, Kin Wing Kwok, Helen Lai Wah Chan, Siu Hong Choy
  • Publication number: 20080128527
    Abstract: A liquid dispensing apparatus, including a hollow horn having a central cylindrical cavity and a piezoelectric ring having a central opening. The piezoelectric ring is coupled to the hollow horn such that the central opening is in communication with one end of the central cylindrical cavity. A mesh screen is provided at the other end of the central cylindrical cavity. Liquid is delivered to an inner surface of the mesh screen through the central opening of the piezoelectric ring and the central cylindrical cavity of the hollow horn, and is dispensed from an outer surface of the mesh screen in the form of fine liquid droplets.
    Type: Application
    Filed: December 5, 2006
    Publication date: June 5, 2008
    Applicant: THE HONG KONG POLYTECHNIC UNIVERSITY
    Inventors: Helen Lai Wa Chan, Wencheng Xu, Kwok Ho Lam, Kin Wing Kwok
  • Publication number: 20080006674
    Abstract: An apparatus and method for detecting the oscillation amplitude of a bonding tool includes a sensing unit disposed adjacent to and at a distance from the bonding tool. The sensing unit includes a pair of electrodes, a piezoelectric sensing layer located between the pair of electrodes, and a membrane associated with the piezoelectric sensing layer. The piezoelectric sensing layer becomes sensitive to ultrasonic vibrations and generates electrical voltage signals after being activated by a poling process. An optional pre-amplifier is used to amplify the signals generated from the sensing unit, and an oscilloscope is used to further process the signals.
    Type: Application
    Filed: July 5, 2006
    Publication date: January 10, 2008
    Inventors: Helen Lai Wa Chan, Tin Yan Lam, Chen Chao, Kin Wing Kwok