Patents by Inventor John C. McGrath

John C. McGrath 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).

  • Broadband, acoustically transparent, nonresonant PVDF hydrophone
    Patent number: 4789971
    Abstract: An acoustically transparent voided, polyvinylidene fluoride (PVDF) hydrope made of material whose impedance matches the characteristic acoustic impedance (.rho.c) of sea water, having drastically reduced diffraction and resonance effects. The frequency response is thus flat at frequencies less than one-half elastic wavelength in the PVDF material. An array of such hydrophones in front of a projector saves space without affecting projector performance.
    Type: Grant
    Filed: April 7, 1986
    Date of Patent: December 6, 1988
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: James M. Powers, Mark B. Moffett, John C. McGrath
  • Uniaxially drawn vinylidene fluoride polymers
    Patent number: 4390674
    Abstract: An elongated material comprising a vinylidene fluoride polymer and having a Young's modulus from 3 to 15 GPa and which, when poled, has a pyroelectric constant from 4 to 15 nC cm.sup.-2 K.sup.-1, or a hydrostatic piezoelectric constant greater than 10 pCN.sup.-1.
    Type: Grant
    Filed: July 21, 1981
    Date of Patent: June 28, 1983
    Assignee: National Research Development Corporation
    Inventors: Ian M. Ward, John C. McGrath