Patents by Inventor Stephen R. Sofen

Stephen R. Sofen 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).

  • Thermographic and photothermographic imaging materials
    Patent number: 5328799
    Abstract: Photothermographic and thermographic diffusion transfer image-recording materials are provided wherein an auxiliary ligand for silver ions is employed to enhance transfer image density and discrimination.
    Type: Grant
    Filed: June 17, 1993
    Date of Patent: July 12, 1994
    Assignee: Polaroid Corporation
    Inventors: James R. Freedman, Stephen R. Sofen, Kent M. Young
  • Stabilization of thermal images
    Patent number: 5206208
    Abstract: The addition, to a thermal imaging medium comprising a color-forming compound which undergoes a change of color upon heating above a color-forming temperature for a color-forming time, the color-formingcompound being of the cyclic sulfonamide type described in U.S. Pat. Nos. 4,720,449 and 4,960,901,of a source of zinc, nickel, copper(II), cobalt(II) or aluminum(III) cations increases the sensitivity of the imaging medium and helps to prevent fading of images produced therefrom while the images are being projected.
    Type: Grant
    Filed: November 20, 1991
    Date of Patent: April 27, 1993
    Assignee: Polaroid Corporation
    Inventors: Rong C. Liang, William C. Schwarzel, Rita S. Shon Baker, Robert P. Short, Stephen R. Sofen, Michael A. Young
  • Silver diffusion transfer film unit with noble metal compound as stabilizer
    Patent number: 4463082
    Abstract: A silver diffusion transfer film unit comprising photosensitive silver halide, silver precipitating nuclei, a stabilizing compound of the formulaXS(CH.sub.2).sub.n COORwherein X is a noble metal below silver in the Electromotive Series of Elements, n is 1, 2 or 3 and R is an alkyl or substituted alkyl group; and a compound of the formulaH.sub.x S.sub.y [(CH.sub.2).sub.b COOZ].sub.mwherein Z is hydrogen or alkyl, b is 1, 2 or 3, m=1 or 2, x=1 or 0 and y=1 or 2; when y=2, m=2 and x=0 and when y=1, m=1 and x=1.
    Type: Grant
    Filed: April 19, 1983
    Date of Patent: July 31, 1984
    Assignee: Polaroid Corporation
    Inventors: John H. Ferguson, Kenneth S. Norland, Stephen R. Sofen