Patents by Inventor Richard T. Ingwall

Richard T. Ingwall 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).

  • Volume phase hologram with liquid crystal in microvoids between fringes
    Patent number: 5198912
    Abstract: Composite holograms are disclosed wherein microvoids between the holographic interference fringes are filled with a liquid crystal. The diffraction efficiency and other holographic properties of such composite holograms may be varied by external stimuli, e.g., application of an electric field of thermal energy.
    Type: Grant
    Filed: July 10, 1991
    Date of Patent: March 30, 1993
    Assignee: Polaroid Corporation
    Inventors: Richard T. Ingwall, Mark A. Troll, Duncan H. Whitney
  • Holograms
    Patent number: 4970129
    Abstract: Volume phase holograms and other holographic elements are disclosed which include microscopic areas of a material having an index of refraction different from that of the holographic fringes.
    Type: Grant
    Filed: March 30, 1988
    Date of Patent: November 13, 1990
    Assignee: Polaroid Corporation
    Inventors: Richard T. Ingwall, Mark A. Troll
  • Photopolymerizable compositions used in holograms
    Patent number: 4588664
    Abstract: Novel photopolymerizable compositions are provided which comprise a dye sensitizer, a branched polyethylenimine as a polymerization initiator and a free radical polymerizable ethylenic unsaturated monomer.In the preferred embodiments, the branched polyethylenimine is used in combination with lithium acrylate. This combination provides dry coatings which may be stored for extended periods prior to being activated for imaging, and which produce volume holograms of very high resolution and diffraction efficiency.
    Type: Grant
    Filed: August 20, 1984
    Date of Patent: May 13, 1986
    Assignee: Polaroid Corporation
    Inventors: Herbert L. Fielding, Richard T. Ingwall
  • Stabilization of holograms
    Patent number: 4535041
    Abstract: Volume phase holograms formed by photopolymerization of a polymerizable monomer, e.g., lithium acrylate, exhibit substantially increased retention of diffraction efficiency when exposed to high humidity if they are sequentially treated with a zirconium compound and a fatty acid.
    Type: Grant
    Filed: August 20, 1984
    Date of Patent: August 13, 1985
    Assignee: Polaroid Corporation
    Inventors: Herbert L. Fielding, Richard T. Ingwall