Patents by Inventor Rudolf Kiefer

Rudolf Kiefer 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).

  • Patent number: 7656490
    Abstract: An electro-optical display device comprising a liquid crystal layer achieves switching using an electric field component which is predominantly parallel to the surface of the liquid crystal layer. Low dependence of image contrast on viewing angle is achieved by selection of parameters including pretilt angle ?0, orientation angle ?0, etc. of the liquid crystal molecules in the layer.
    Type: Grant
    Filed: April 4, 1996
    Date of Patent: February 2, 2010
    Assignee: Merck Patent Gesellschaft
    Inventors: Gunter Baur, Waltraud Fehrenbach, Barbara Weber Ne Staudacher, Friedrich Windscheid, Rudolf Kiefer
  • Patent number: 5841499
    Abstract: An electro-optical display device comprising a liquid crystal layer achieves switching using an electric field component which is predominantly parallel to the surface of the liquid crystal layer. Low dependence of image contrast on viewing angle is achieved by selection of parameters including pretilt angle .alpha..sub.0, orientation angle .beta..sub.0, etc. of the liquid crystal molecules in the layer. Reflection mode devices are described.
    Type: Grant
    Filed: April 4, 1996
    Date of Patent: November 24, 1998
    Assignee: Merck Patent Gesellschaft Mit Beschrankter Haftung
    Inventors: Gunter Baur, Waltraud Fehrenbach, Barbara W. Ne Staudacher, Friedrich Windscheid, Rudolf Kiefer
  • Patent number: 5841498
    Abstract: An electro-optical display device comprising a liquid crystal layer achieves switching using an electric field component which is predominantly parallel to the surface of the liquid crystal layer. Low dependence of image contrast on viewing angle is achieved by selection of parameters including orientation angle .beta..sub.o, and others, of the liquid crystal molecules in the layer.
    Type: Grant
    Filed: April 4, 1996
    Date of Patent: November 24, 1998
    Assignee: Merck Patent Gesellschaft Mit Beschrankter Haftung
    Inventors: Gunter Baur, Waltraud Fehrenbach, Barbara Weber Ne Staudacher, Friedrich Windscheid, Rudolf Kiefer
  • Patent number: 5576867
    Abstract: An electro-optical display device comprising a liquid crystal layer achieves switching using an electric field component which is predominantly parallel to the surface of the liquid crystal layer. Low dependence of image contrast on viewing angle is achieved by selection of parameters including orientation angle .beta..sub.o and pretilt angle .alpha..sub.o of the liquid crystal molecules in the layer. For example, good results are achieved when 0.degree.<.beta..sub.o .ltoreq.20.degree. for liquid crystal molecules having negative dielectric anisotropy and 70.degree..ltoreq..beta..sub.o <90.degree. for molecules having positive dielectric anisotropy. Preferably, 0.degree..ltoreq..alpha..sub.o <30.degree..
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: November 19, 1996
    Assignee: Merck Patent Gesellschaft mit beschrankter Haftung
    Inventors: Gunter Baur, Waltraud Fehrenbach, Barbara Weber nee Staudacher, Friedrich Windscheid, Rudolf Kiefer
  • Patent number: 4702945
    Abstract: An optical recording medium contains, on a base, one or more dyes and a polymer which forms liquid-crystalline phases.The information is written into the uniformly oriented liquid-crystalline polymer layer, for example by means of a laser. During this procedure, the polymer heats up locally to above a phase transition temperature. By cooling, the resulting change is frozen in the glass state.The information can be erased by applying an electric field and/or heating.The recording material permits high-contrast storage and possesses high sensitivity, good resolution and excellent stability.
    Type: Grant
    Filed: August 9, 1985
    Date of Patent: October 27, 1987
    Assignee: BASF Aktiengesellschaft
    Inventors: Karl-Heinz Etzbach, Peter Neumann, Matthias Dust, Helmut Ringsdorf, Hans-Werner Schmidt, Guenter Baur, Friedrich Windscheid, Rudolf Kiefer