Nokia Unterhaltungselektronik

Nokia Technology Gmbh

Nokia (deutschland) Gmbh

Nokia Unterhaltungselektronik (deutschland) Gmbh

Deutsches Zentrum Fur Luft-und Raumfahrt E.v.

Ed. Zublin Aktiengesellschaft

Strabag Rail Gmbh

Strabag Offshore Wind Gmbh

Stefan Brosig

Jurgen Waldmann

Helmut Thaler

Hansjorg Wirsig

Monika Stoitzner

Hans-Jorg Wirsig

Martin Barnaba

Robert Graf

Michael Fiss

Jan Sommer

Peter-Michael Mayer

Christoph Niklasch

Wolf-Dieter Steinmann

Viktor Enoekl

Dörte Laing

Dominik Hörrle

Thomas Voigt

Carsten Bahl

Thomas Brand

According to the state of the art, LC displays are known whose torsion angle is between about 180.degree. and 300.degree.. Such displays exhibit good independence of angle of view of white impression and contrast, but they are not gray scale capable and are not free of hysteresis. For that reason, the invention presents a display (10) whose product of plate separation (d) and anisotropy of the angle of refraction is equal to or greater than 0.45 and smaller than 0.65 .mu.m, whose torsion angle .phi. is between 260.degree. and 360.degree., whose liquid crystal molecules (18) have an approach angle .theta. between 7.degree. and 25.degree., and encompass a liquid crystal material between the substrate plates (11) in which the relationship of the elastic constant K.sub.3 to the elastic constant K.sub.1 is between 1.4 and 0.6. The angular relationships (.beta., .gamma.) of the polarization directions P.u, P.o with the respective orientation direction .eta..u, .eta..o is a function of torsion angle .phi.. An improvement of the contrast relationships is provided, if the relationship between the upper polarization direction P.o and the lower polarization direction P.u is smaller than 90.degree..

Liquid crystal display

With a view to improving the resolution of passively controlled liquid crystal displays, the invention proposes that at least the orientation layer (14.1, 14.2) of one of the two substrate plates (3,4) of the liquid crystal display should be made up of a highly fluorated and preferably perfluorated, aliphatic polymer, which could be, among others, Teflon AF 1600 marketed by the Dupont Company. An orientation layer formed in accordance with the invention also makes it possible for organic dyestuffs to be used as the chromophore layer, because an orientation layer in accordance with the invention only requires heat treatment temperatures not exceeding 250.degree. C. The pretilt angles obtained by means of the orientation layers in accordance with the invention can be set during the manufacturing process and lie in the range between 25.degree. and about 90.degree..

High-resolution, passively controlled liquid crystal display

The invention concerns a method of determining the angle of attack (pretilt angle) of liquid crystal molecules in a liquid crystal display (LCD) provided with top and bottom cover plates. The following steps are proposed for a simple and cheap determination: addition of a dichroic dye (17) to the liquid crystal (5) in order to cause the dye molecules (18) to become aligned by the crystal molecules (6), which are present in a twist-free state, determination by measurement of a maximum absorption value, the said measurement being carried out by causing a polarized ray of light (19) (measuring ray) to pass through the liquid crystal display (1) and varying its angle of inclination (.alpha.) with respect to the plane of the cover plates (2,3), and then using the angle of inclination (.alpha.) associated with the maximum absorption for determining the angle of attack (.delta.).

Method of determining the pretilt angle of liquid crystal molecules

In a process for treating an organic orientation layer on a substrate plate for a liquid crystal cell, the orientation layer for causing the orientation is rubbed in the conventional way in a specified direction. Rubbing is then performed in the opposite direction, but with a weaker rubbing pressure. Rubbing in the opposite direction with weak pressure leads to an increase of some degrees in the pretilt angle, and this is essentially independent of the material used for the orientation layer.

Process for increasing pretilt angles in nematic liquid crystal cells

A method of producing a substrate plate for a liquid crystal cell with black matrix areas in which blackened polymer material is already deposited before the structured areas of photosensitive resist overlying the structured electrode areas are removed. Rather, these structured areas of photosensitive resist are removed only after the blackened polymer material has been hardened. This processing sequence has the advantage that no special alignment processes are needed in order to arrange the black matrix areas accurately between the electrode areas. This alignment is obtained autonomously by virtue of the fact that the electrode areas, even after they have been structured with the help of the photosensitive resist areas, are still covered by these selfsame photosensitive resist areas, thereby ensuring in an ideal manner that only the areas between the electrode areas will be filled with black matrix material and this in such a way as to make them butt directly against the electrode areas, so that the maximum possible surface will be covered by black matrix material.

Method of producing a substrate plate for a liquid crystal cell with

In a process to manufacture a liquid crystal cell, one of the two plates is provided with an adhesive edge strip. A quantity of liquid crystal which is required to form the liquid crystal layer is applied to one of the two plates and the two plates are brought together and positioned in the vacuum and bonded tightly together by the adhesive curing. By the fact that the plates with the correct quantity of liquid crystal on one of the plates are joined together in the vacuum, it is no longer necessary to evacuate the inner space between the plates in a time-comsuming process and apply liquid crystal through a small filling hole in another time-consuming process.

Method and jig for LCD-production

In a process for applying orientation layers to cell plates (11.o, 11.u), the cell plates are arranged in relation to a centrifuge rotational axis (14) so that the plate planes lie parallel to the rotational axis. The centrifugal forces then act over the entire plate surfaces in the same direction in each case. This leads to a homogeneous pre-alignment of the orientation layer molecules. Because a homogeneous pre-alignment of orientation layer molecules can be achieved with this process, an improved orientation effect can be obtained.

After it has been evacuated, a liquid crystal cell whose filling hole is located at a corner of the cell is immersed into a liquid crystal material inside a vacuum jar and immediately raised again, whereby a drop of liquid crystal material forms at the filling hole. Then the vacuum jar is quickly aerated and the cell is filled outside the vacuum jar. The volume of the drop and the volume of the cell have to be brought into line with each other in such a way that the drop volume is at least as great as the volume of the cell interior so that filling can take place with the drop volume only. Due to the fact that filling is accomplished by a method which only involves lowering the liquid crystal cell a short distance, raising it and then holding it with the filling hole downwards until the volume of the drop which has formed following immersion in and withdrawal from the liquid crystal material is completely sucked into it, the process is extremely simple and entails no great device expense while being reliable in operation. A further advantage is that the vacuum jar is occupied for the shortest possible time.

Process for filling a liquid crystal cell

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Stuttgart, Germany

Stefan Brosig