Patents by Inventor David K. Chu

David K. Chu 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: 5447845
    Abstract: This invention relates to analyte-responsive compositions and analyte detection methods using these compositions, and, more particularly, to such compositions based on potassium titanyl phosphate (KTP) and analogs thereof and to analyte detection methods based on piezoelectric and optical properties of materials.
    Type: Grant
    Filed: December 6, 1994
    Date of Patent: September 5, 1995
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: David K. Chu, Richard C. Ebersole, Hui Hsiung
  • Patent number: 5448125
    Abstract: Devices are disclosed for controlling high frequency signals by the generation of surface skimming bulk waves (SSBWs). The devices include (a) a bulk crystalline substrate of MTiOXO.sub.4 (M is K, Rb, Tl, Cs, and/or NH.sub.4 and X is P and/or As) having mm2 crystal symmetry and a planar-cut surface, (b) an input interdigital transducer (IDT) deposited on a signal receiving area of the substrate surface, suitable for connection to a source of electric signal and for inverse piezoelectrically generating in-plane polarized surface skimming bulk waves having a velocity in the substrate of between about 4200 m/s and 7000 m/s, (c) a second IDT deposited on a signal sending area of the substrate surface suitable for piezoelectrically generating electric output signals from said surface skimming bulk waves, and (d) an electric signal responsive device which is operably connected to the second IDT and responds to the electric output signals.
    Type: Grant
    Filed: June 27, 1994
    Date of Patent: September 5, 1995
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: David K. Chu
  • Patent number: 5418866
    Abstract: Devices for controlling high frequency signals such as optic or electric signals are disclosed which utilize guided and/or reflected surface acoustic waves. The devices preferably use crystalline substrates modified (e.g., by ion exchange to increase mass density) to contain acoustic reflectors and/or continuous acoustic waveguiding channels (optionally, in combination with optical features such as optical waveguiding channels) and interdigital transducers deposited thereon to provide frequency generation (and reception where high frequency electrical signals are controlled). The preferred crystal substrates are of a material having a piezoelectric-elastic dielectric matrix capable of the generation of acoustic waves, such as MTiOXO.sub.4 (where M is K, Rb, Tl, and/or NH.sub.4 and X is P and/or As) having mm2 symmetry.
    Type: Grant
    Filed: October 8, 1993
    Date of Patent: May 23, 1995
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: David K. Chu
  • Patent number: 5350961
    Abstract: Devices are disclosed for controlling high frequency signals such as optic or electric signals by the generation of acoustic waves. The devices use certain bulk or surface-modified crystalline substrates which have a surface with a receiving area and an input interdigital transducer deposited on the signal receiving area of the substrate surface which is suitable for connection to a source of signal and for inverse piezoelectrically generating acoustic waves in the crystalline substrate. The crystal substrates are of a material having a piezoelectric-elastic dielectric matrix capable of the generation of acoustic waves and for bulk substrates, are of MTiOXO.sub.4 (where M is K, Rb, Tl, and/or NH.sub.4 and X is P and/or As) having mm2 symmetry.
    Type: Grant
    Filed: July 31, 1992
    Date of Patent: September 27, 1994
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: David K. Chu