Patents by Inventor Burkhard Knippenberg

Burkhard Knippenberg 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).

  • Liquid-crystal mixture with a pleochroic anthraquinone dye, and method for producing such a dye
    Patent number: 4491532
    Abstract: Liquid-crystal mixture with a pleochroic anthraquinone dye of the general formula ##STR1## with R.sup.1, R.sup.3, R.sup.4, R.sup.6 =H, OH, OCH.sub.3, NH.sub.2, NHCH.sub.3, NO.sub.2, characterized by the feature that ##STR2## (R.sup.7 =H, alkyl, cycloalkyl, alkoxy, alkylmercapto, amino, alkylamino, dialkylamino, nitro, cyano, halogen), ##STR3## COOR.sup.9, CH.sub.2 --OR.sup.9 (R.sup.8 =H, alkyl, cycloalkyl, alkoxy, alkylmercapto, amino, alkylamino, dialkylamino, nitro, cyano, halogen); R.sup.9 =H, alkyl and either R.sup.1, R.sup.4 =H, OH, NH.sub.2, NHCH.sub.3, NO.sub.2, NHCH.sub.3, NO.sub.2, OCH.sub.3, where at least one of the two radical is an NH.sub.2 or an NHCH.sub.3, R.sup.3 =R.sup.6 =H, or R.sup.3, R.sup.6 =H, OH, NH.sub.2, NHCH.sub.3, NO.sub.2, OCH.sub.3, where at least one of the two radicals is an NH.sub.2 or an NHCH.sub.3, R.sup.1 =R.sup.4 =H.
    Type: Grant
    Filed: September 10, 1981
    Date of Patent: January 1, 1985
    Assignee: Siemens Aktiengesellschaft
    Inventors: Gunther Scherowsky, Alexander Moller, Gerd Heppke, Burkhard Knippenberg