Patents by Inventor Ha K. Cheung

Ha K. Cheung 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).

  • Method of making niobium-activated yttrium tantalate x-ray phosphor
    Patent number: 5380463
    Abstract: The brightness and particle size of a niobium-activated yttrium tantalate x-ray phosphor can be increased by the addition of either barium fluorosilicate or calcium fluorosilicate thereto.
    Type: Grant
    Filed: May 13, 1994
    Date of Patent: January 10, 1995
    Assignee: Osram Sylvania Inc.
    Inventors: Vaddi B. Reddy, Ha K. Cheung
  • Unactivated yttrium tantalate phosphor
    Patent number: 5112524
    Abstract: An unactivated yttrium tantalate phosphor, M'YTaO.sub.4, contains one or more additives of Sr, Rb and Al in order to improve brightness under X-radiation.
    Type: Grant
    Filed: July 19, 1991
    Date of Patent: May 12, 1992
    Assignee: GTE Products Corporation
    Inventors: Vaddi B. Reddy, Ha K. Cheung