Patents by Inventor Hyman Cohen

Hyman Cohen 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).

  • Pathlength controller for ring laser gyroscope
    Patent number: 4561780
    Abstract: A pathlength controller for a ring laser gyroscope with a modulated mirror is disclosed where a voltage bias is applied to the modulation signal to prevent starting the ring laser gyroscope at a point where it operates with two equal longitudinal modes.
    Type: Grant
    Filed: April 28, 1980
    Date of Patent: December 31, 1985
    Assignee: The Singer Company
    Inventors: Bo H. G. Ljung, Hyman Cohen
  • Photographic film units containing a polymeric mordant which covalently bonds with certain dyes
    Patent number: 4201840
    Abstract: A photographic element comprising a support, a layer containing certain photographically useful and/or active fragments and a layer containing a dye mordant composition comprising a polymer having recurring units of the formula selected from the group consisting of: ##STR1## wherein: R.sup.2 is hydrogen or alkyl;R.sup.1 is hydrogen, alkyl or aryl;L is a linking group;W is an electron-withdrawing group;X is a leaving group; andn is 0 or 1.The polymeric mordants covalently bond with dyes or dye precursors and are especially useful in diffusion transfer processes.
    Type: Grant
    Filed: February 22, 1979
    Date of Patent: May 6, 1980
    Assignee: Eastman Kodak Company
    Inventors: Gerald A. Campbell, Hyman Cohen, Lewis R. Hamilton, George Villard
  • Photographic film units containing a polymeric mordant which covalently bonds with certain dyes
    Patent number: 4193795
    Abstract: A photographic element comprising a support, a layer containing certain photographically useful and/or active fragments and a layer containing a dye mordant composition comprising a polymer having recurring units of the formula selected from the group consisting of: ##STR1## wherein: R.sup.2 is hydrogen or alkyl;R.sup.1 is hydrogen, alkyl or aryl;L is a linking group;W is an electron-withdrawing group;X is a leaving group; andn is 0 or 1.The polymeric mordants covalently bond with dyes or dye precursors and are especially useful in diffusion transfer processes.
    Type: Grant
    Filed: May 15, 1978
    Date of Patent: March 18, 1980
    Assignee: Eastman Kodak Company
    Inventors: Gerald A. Campbell, Hyman Cohen, Lewis R. Hamilton, George Villard
  • Photographic elements containing cross-linked mordants and processes of preparing said elements
    Patent number: 3958995
    Abstract: A process for preparing photographic elements comprising a support, a layer containing an acid dye or acid dye precursor and a layer containing a dye mordant composition, said process comprising coating on a support with a substantially aqueous dispersion of a polymer containing units according to the formula: ##SPC1##Wherein A represents units of an addition-polymerizable monomer containing at least 2 ethylenically-unsaturated groups; B represents units of a copolymerizable ethylenically unsaturated monomer; Q is N or P; R.sup.1, R.sup.2 and R.sup.3 are independently selected from the group consisting of carbocyclic groups and alkyl groups; M.sup.- is an anion and x is from about 0.25 to about 5 mole percent; y is from about 0 to about 90 mole percent and z is from about 10 to about 99 mole percent; and applying a layer containing acid dyes or acid dye precursors. The polymeric mordants are especially useful in diffusion transfer processes.
    Type: Grant
    Filed: November 19, 1974
    Date of Patent: May 25, 1976
    Assignee: Eastman Kodak Company
    Inventors: Gerald A. Campbell, Hyman Cohen, Lewis R. Hamilton