Patents by Inventor Devendra S. Parmar

Devendra S. Parmar 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: 5309767
    Abstract: A pressure sensor includes a liquid crystal positioned between transparent, electrically conductive films (18 and 20), that are biased by a voltage (V) which induces an electric field (E) that causes the liquid crystal to assume a first state of orientation. Application of pressure (P) to a flexible, transparent film (24) causes the conductive film (20) to move closer to or farther from the conductive film (18), thereby causing a change in the electric field (E'(P)) which causes the liquid crystal to assume a second state of orientation. Polarized light (P.sub.1) is directed into the liquid crystal and transmitted or reflected to an analyzer (A or 30). Changes in the state of orientation of the liquid crystal induced by applied pressure (P) result in a different light intensity being detected at the analyzer (A or 30) as a function of the applied pressure (P).
    Type: Grant
    Filed: October 9, 1992
    Date of Patent: May 10, 1994
    Assignee: Center for Innovative Technology
    Inventors: Devendra S. Parmar, Harlan K. Holmes
  • Patent number: 5270781
    Abstract: The laminate structure comprises a liquid crystal polymer substrate attached to a test surface of an article. A light absorbing coating is applied to the substrate and is thin enough to permit bonding steric interaction between the liquid crystal polymer substrate and an overlying liquid crystal monomer thin film. Light is directed through and reflected by the liquid crystal monomer thin film and unreflected light is absorbed by the underlying coating. The wavelength of the reflected light is indicative of the shear stress experienced by the test surface.
    Type: Grant
    Filed: February 8, 1993
    Date of Patent: December 14, 1993
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Jag J. Singh, Abe Eftekhari, Devendra S. Parmar
  • Patent number: 5223310
    Abstract: The laminate structure comprises a liquid crystal polymer substrate attached to a test surface of an article. A light absorbing coating is applied to the substrate and is thin enough to permit bonding steric interaction between the liquid crystal polymer substrate and an overlying liquid crystal monomer thin film. Light is directed through and reflected by the liquid crystal monomer thin film and unreflected light is absorbed by the underlying coating. The wavelength of the reflected light is indicative of the shear stress experienced by the test surface.
    Type: Grant
    Filed: March 2, 1992
    Date of Patent: June 29, 1993
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Jag J. Singh, Abe Eftekhari, Devendra S. Parmar