Search Patents
  • Liquid crystalline ferroelectric derivatives of branched acyclic alpha-chlorocarboxylic acids
    Patent number: 4961876
    Abstract: Liquid crystalline ferroelectric derivatives of branched acyclic alpha-chlorocarboxylic acids of the general formula I ##STR1## wherein n=0 or 1; m=0 or 1, o=0 or 1; p=0 or 1X=--COO--, --OOC--, or --CH.sub.2 --CH.sub.2 --Y=X, --CH.sub.2 --, --N.dbd.N--, or --N.dbd.N(O)--, ##STR2## It was discovered that, by reacting chiral alpha-chlorocarboxylic acids or alpha-chlorocarboxylic acid chlorides or bromides, synthesized from natural alpha-amino acids by reaction with nitric and hydrochloric acids, with appropriate hydroxy compounds directly or in the presence of strongly dehydrating substances, preferably carbodiimides, liquid crystalline ferroelectric substances of the general formula I are formed.The inventive substances by themselves, in mixtures with one another as well as with other liquid crystalline substances or substances which are not liquid crystalline, can form liquid crystalline ferroelectric phases, which make them suitable for use in displays.
    Type: Grant
    Filed: September 15, 1988
    Date of Patent: October 9, 1990
    Assignee: VEB Werk fuer Fernsehelektronik im VEB Kombinat Mikroelektronik
    Inventors: Dietrich Demus, Horst Zaschke, Wolfgang Weissflog, Kristina Mohr, Saskia Kohler, Kerstin Worm
  • Esters of 4-[2,2-dicyano-ethenyl]-phenols
    Patent number: 4363767
    Abstract: The invention relates to liquid-crystalline nematic mixtures which are used in electro-optical components, as well as to methods for their preparation.The object of the invention is liquid-crystalline mixtures for electro-optical arrangements possessing high positive electrical anisotropy at a high clarification point, as well as methods for their preparation.According to the invention, liquid-crystalline nematic mixtures are used, wherein at least one component is a 1,4-disubstituted benzene derivative and the other compound is an ester of 4-[2,2-dicyano-ethenyl]-phenol of the general formula ##STR1## wherein R.sup.1 denotes added groups of various characters such as alkyl or alkoxy for example, X is aromatic, cycloaliphatic or a heterocyclic ring system such as phenyl or cyclohexyl for example; and Y is a connector such as carbonyloxy, azomethine, azoxy.These are prepared by reaction with reactive acid derivatives, particularly acid chlorides, or by a Knoevenagel-condensation by reacting respective 4-subst.
    Type: Grant
    Filed: October 3, 1980
    Date of Patent: December 14, 1982
    Assignee: VEB Werk fur Fernsehelektronik Berlin im VEB Kombinat Mikroelektronik
    Inventors: Dietrich Demus, Wolfgang Weissflog, Horst Zaschke, Rudolf Wolff, Horst Kresse
  • Liquid crystalline 5-alkyl-2 (4-acyloxy-phenyl)-pyrimidine
    Patent number: 4311610
    Abstract: The invention relates to the application of nematic liquid-crystalline substances in electro-optical device elements for the display of numbers, symbols and images.Such nematic liquid crystals having low melting points and extremely high temperatures of transparency.The nematic liquid-crystalline substances are 5-alkyl-2-[4-acyloxyphenyl]-pyrimidines having the general formula ##STR1## wherein ##STR2## R.sup.1 =C.sub.n H.sub.2n+1, C.sub.n H.sub.2n+1 O, C.sub.n H.sub.2n+1 OCOO, C.sub.n H.sub.2n+1 COO, C.sub.n H.sub.2n+1 S, F, Cl, Br, NO.sub.2, CN CF.sub.3R.sup.2 =C.sub.n H.sub.2n+1n denotes any of the numbers between 1 and 10.These substituted pyrimidines are used in electro-optical device elements singly or as mixtures of each other, as well as mixtures with other liquid-crystalline or non liquid-crystalline components.
    Type: Grant
    Filed: August 20, 1980
    Date of Patent: January 19, 1982
    Assignee: VEB Werk fur Fernsehelektronik im VEB Kombinat Mikroelektronik
    Inventors: Horst Zaschke, Dietrich Demus, Adalbert Wiegeleben, Uta Bottger
  • 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
  • Nematic liquid crystals of 5-cyano-2-[4-acyloxyphenyl]-pyrimidines and mixtures containing the same
    Patent number: 4358393
    Abstract: Nematic liquid crystals are employed in electro-optical devices for the modulation of the transmittant or incident light and for the black and white or colored rendition of numerals, symbols and pictures.The object of the invention is the use of nematic liquid crystals having a high positive dielectric anisotropy, a low threshold and operating voltage and high clear points and a process for making these compounds.It was found that as liquid crystals for electro-optical devices mixtures are useful which, as an essential component, contain one or several compounds from the class of 5-cyano-2-[4-acyloxyphenyl]-pyrimidines of the formula ##STR1## wherein R.sup.1 is ##STR2## C.sub.5 H.sub.11 -- or C.sub.n H.sub.2n+1 O-- R.sup.2 is C.sub.n H.sub.2n+1 ; C.sub.n H.sub.2n+1 O; C.sub.n H.sub.2n+1 S; F; Cl; Br; CF.sub.3 ; C.sub.n H.sub.2n+1 COO; C.sub.n H.sub.2n+1 OCOO; CN; NO.sub.2 ; C.sub.n H.sub.2n+1 NH; or C.sub.n H.sub.2n+1 (CH.sub.3)N, n is 1 to 10, andR.sup.3 is C.sub.n H.sub.2n+1,n is 1 to 10.
    Type: Grant
    Filed: April 30, 1980
    Date of Patent: November 9, 1982
    Assignee: VEB Werk fur Fernsehelektronik im VEB Kombinat Mikroelektronik
    Inventors: Horst Zaschke, Dietrich Demus, Sylvia Deresch
  • Crystalline lanthanum-oxy-halide phosphor activated with rare earths
    Patent number: 4793944
    Abstract: The invention concerns a crystalline lanthanum-oxy-halide phosphor activated with rare earths which emits light in the ultraviolet and blue spectral range by high-energy excitation, particularly X-ray excitation. Such phosphors are used, for instance, in X-ray image converters, particularly in X-ray amplifying screens. It is the object and purpose of the invention to state a new oxy-halide phosphor with changed composition which ensures a high image quality of corresponding amplifying screens and at sufficiently little phosphorescence renders an optimal conversion of the X-rays to the photographically effectual luminescence possible. This is achieved by simultaneous use of thulium and gadolinium as activators where the phosphor represents the general formula La.sub.1-y-z OX:Tm.sub.y.sup.3+, in which X=Cl and/or Br and y represents values from 0.0001 to 0.1 preferably from 0.0005 to 0.005 as well as z represents values from 0.001 to 0.3 preferably from 0.002 to 0.05.
    Type: Grant
    Filed: September 30, 1987
    Date of Patent: December 27, 1988
    Assignee: VEB Mikroelektronik, Leuchtstoffwerk Bad Liebenstein
    Inventors: Gerhard Herzog, Detlef Starick, Walter Tews, Franz Braunholz, Aleksander M. Gurvic, Svetlana I. Golovkova, Karl Dietzel
  • Nematic liquid crystal mixtures
    Patent number: 4348298
    Abstract: A nematic liquid crystal mixture for modulation of the transmitted or incident light and for rendition of colored numerals, symbols and images in electro-optical devices, the said mixture comprising(a) a nematic liquid crystal adapted for reorientation in an electrical field due to its dielectric anisotropy and(b) a dichroic dyestuff adapted for simultaneous orientation changes together with the said nematic liquid crystal between a light absorption and a light transmission position based on the guest-host effect, the said dyestuff being an s-tetrazine derivative having an elongate molecular structure and having the formula ##STR1## wherein X is ##STR2## R.sup.1 and Y is R.sup.2 -- or ##STR3## R.sup.1 being H--, F--, Cl--, Br--, J--, O.sub.2 N--, NC--, HO--, H.sub.2 N--, C.sub.n H.sub.2n+1 NH--, C.sub.n H.sub.2n+1 (CH.sub.3)N--, C.sub.n H.sub.2n+1" --, C.sub.n H.sub.2n+1 O--, C.sub.n H.sub.2n+1 S--, C.sub.n H.sub.2n+1 COS--, C.sub.n H.sub.2n+1 COO--, C.sub.n H.sub.2n+1 OOC--, C.sub.n H.sub.2n+1 CO-- or C.sub.
    Type: Grant
    Filed: March 31, 1980
    Date of Patent: September 7, 1982
    Assignee: VEB Werk fur Fernsehelektronik im Veb Kombinat Mikroelektronik
    Inventors: Horst Zaschke, Rudolf Wolff, Gerhard Pelzl, Dietrich Demus
  • Method for the production of a self-supporting mask
    Patent number: 4497884
    Abstract: The invention relates to a method for the production of a self-supporting spacing mask for a particle radiation-projection system, especially for the selective structuring and/or doping when producing highly integrated circuits.According to the invention, layers of varying compositions are deposited onto a substrate, structured and then partially or completely removed, until the mask structure which is backed by a stable metal grid is produced on the substrate, whereby a special pattern, made like a nuclear filter with statistically distributed pores is used for grid formation.
    Type: Grant
    Filed: September 22, 1982
    Date of Patent: February 5, 1985
    Assignee: VEB Zentrum fur Forschung Und Technologie Mikroelektronik
    Inventors: Frank Schmidt, Horst Tyrroff
  • Liquid crystal substances for the guest-host effect
    Patent number: 4601846
    Abstract: The invention relates to liquid crystal compounds for the guest-host effect having a positive contrast, pure red color and exhibiting excellent stability. The compounds herein are derivatives of tetrazine of the general formula: ##STR1## in which m and n are 1 to 10. Other related compounds, mixtures and compositions thereof, and opto-electronic displays are described also.
    Type: Grant
    Filed: April 13, 1984
    Date of Patent: July 22, 1986
    Assignee: VEB Werk fuer Fernsehelektronik im VED Kombinat Mikroelektronik
    Inventors: Dietrich Demus, Horst Zaschke, Gerhard Pelzl, Hartmut Enzenberg, Andreas Isenberg
  • Gate controlled semiconductor device
    Patent number: 4550332
    Abstract: A gate-controlled semiconductor device comprises a semiconductor substrate disposed on a support element, where the semiconductor substrate has a recess protruding from the top surface into the semiconductor substrate for forming a gate electrode. An insulating layer covers the semiconductor and the recess and has at least two openings each having an electrode attached. In the semiconductor an npnp-transition is formed, which can be fired and interrupted by the gate electrode. The semiconductor device is useful in power control circuits, where it is important to control and switch large power signals with very small control signals.
    Type: Grant
    Filed: November 9, 1981
    Date of Patent: October 29, 1985
    Assignee: Veb Zentrum fur Forschung und Technologie Mikroelektronik
    Inventor: Siegfried Wagner
  • Apparatus for guiding gas for LP CVD processes in a tube reactor
    Patent number: 4509456
    Abstract: An apparatus for guiding gas through a tube reactor in low pressure chemical vapor deposition processes. The apparatus includes the tube reactor, a substrate mounting element in the interior of the tube reactor, to receive substrates in a generally parallel position with respect to each other along the substrate mounting element, a cup-shaped inner tube surrounding the substrate mounting element, a gas feed arranged within the inner tube, a gas discharge opening arranged in the inner tube at a point opposite to the gas feed, and an intermediate zone between the tube reactor and the inner tube. Preferably, the inner tube is eccentrically disposed within the tube reactor, to increase the size of the intermediate zone in the area of the gas discharge opening, thus facilitating passage of exhaust gas out of the inner tube. Typically, the substrate mounting can be rotated.
    Type: Grant
    Filed: June 18, 1982
    Date of Patent: April 9, 1985
    Assignee: VEB Zentrum fur Forschung und Technologie Mikroelektronik
    Inventors: Michael Kleinert, Rainer Moller, Horst Stelzer
  • Nematic liquid crystals and method of production
    Patent number: 4519936
    Abstract: The invention relates to nematic liquid crystals in electro-optical components for the modulation of light as well as for the representation of numerals, signs and images and to a method for producing the same.It is the object of the invention to create nematic liquid crystals which are well suited for electro-optical devices, preferably for two-frequency operation.It has been found that pure or mixed 2-n-alkyl-1, 4-bis-[4-acyloxy]-benzenes of the general formula ##STR1## wherein R.sup.3 =n-C.sub.m H.sub.2m+1, with m=3 to 14, are well suited for utilization in electro-optical components.It was found that 2-n-alkyl-1,4-bis-[acyloxy]-benzene which is well suited for electro-optical components, and especially for two-frequency operations, can be produced by the conversion of a correspondingly substituted benzoic acid or cyclohexane carboxylic acid or a reaction-capable derivative thereof with the corresponding 2-n-alkylhydroquinone--also in the form of its phenylate--at a temperature ranging from 0.degree. C.
    Type: Grant
    Filed: July 20, 1982
    Date of Patent: May 28, 1985
    Assignee: VEB Werk fuer Fernsehelektronik im Kombinat Mikroelektronik
    Inventors: Dietrich Demus, Wolfgang Weissflog, Horst Kresse
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