Patents by Inventor Fred Walkow

Fred Walkow 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).

  • Diazonium salts and a diazo-type material comprising these diazonium salts
    Patent number: 4400458
    Abstract: It is the purpose and object of the present invention to make better use of the emission range of light sources and to create the diazonium salts necessary for such purpose. The diazonium salts of the present invention of the general formula ##STR1## wherein Y is ##STR2## R.sub.1, R.sub.2 are equal or different and are, alkyl having 1 to 10 carbon atoms, aryl having 6 to 10 carbon atoms in a mono or polycylic ring;R.sub.3 is hydrogen, halogen, alkyl, alkoxy, cyano;R.sub.4 is hydrogen, halogen, alkyl, alkoxy; andX.sup.e is an anion,can be employed with all known couplers and additives in diazotype materials. They have an absorption range of 480 to 550 nm.
    Type: Grant
    Filed: September 14, 1981
    Date of Patent: August 23, 1983
    Assignee: VEB Filmfabrik Wolfen
    Inventors: Fred Walkow, Peter Czerney, Horst Hartmann, Jorg Marx