Patents by Inventor Doris Pfeiffer

Doris Pfeiffer 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).

  • Nematic liquid crystal compounds and use and device for using the same
    Patent number: 4391730
    Abstract: A nematic liquid crystal for modulating light in electrooptical devices comprises:A. A 5-substituted-2-(4-substituted-phenyl)-pyrimidine of the formula ##STR1## or a homolog thereof, R.sup.1 and R.sup.2 being the same or different and being selected from the group consisting of C.sub.n H.sub.2n+1 --, C.sub.n H.sub.2n+1 O--, C.sub.n H.sub.2n+1 COO-- or C.sub.n H.sub.2n+1 CO-- and n=1 to 12;B. A 4-substituted-cyclohexanecarboxylic acid-(4-substituted-phenylester) of the formula ##STR2## or a homolog thereof, R being --C.sub.m H.sub.2m+1, --OC.sub.m H.sub.2m+1, --COC.sub.m H.sub.2m+1, --CN or --NO.sub.2, and n, m=1-10, andC. A 4-substituted-benzoic acid-(4-cyanophenylester) of the formula ##STR3## or a homolog thereof, R being C.sub.n H.sub.2n+1 -- or C.sub.n H.sub.2n+1 O-- and n=1 to 14.
    Type: Grant
    Filed: September 2, 1980
    Date of Patent: July 5, 1983
    Assignee: VEB Werk fuer Fernsehelektronik Berlin im VEB Kombinat Mikroelektronik
    Inventors: Frank Kuschel, Dietrich Demus, Doris Pfeiffer, Hans-Joachim Deutscher