DE10241301A1 - Electrooptic light control element and display and medium for television and computer screens has temperature driven control mechanism - Google Patents

Abstract

An electro-optic light control element comprises electrodes (3,4), polarizing elements and a control medium (2) on a substrate (1,1'). The control is temperature-driven and does not control in the isotropic phase, neighboring conductors are not more than 20 microns apart and are separated by dielectric layers from one another and the substrate. An Independent claim is also included for an electro-optic display using the above.

Description

Field of the Invention

The present invention relates to light control elements and displays containing them. The light control elements preferably use control media which have anisotropic properties at certain temperatures, such as. B: liquid crystals. The light control elements are operated at a temperature at which the control media are in the isotropic phase. Such displays are in the previously unpublished patent application DE 102 172 73.0 dated April 18, 2002, a further application by the applicant of the present application.

The present invention relates to an electro-optical light control element and containing such elements electro-optical displays and display systems such as television screens and computer monitors. The light control elements according to the invention contain a mesogenic control medium that is used when operating the light control elements is in the isotropic phase. They are next to a good contrast and a low dependence of the contrast on the viewing angle characterized by very short switching times.

The present invention further relates to Media and their use as control media in such light control elements.

Task and State of the art

Conventional electro-optic liquid crystal displays are generally known. They are operated at a temperature at which the control medium is in a mesophase, in most display types in the nematic phase. In the mesophase, the control media already have anisotropic properties, such as birefringence (Δn). This is not only induced by an electric field. The most widespread are TN (English: "twisted nematic") and STN (English: "super twisted nematic") displays. The liquid crystal cells of these displays have electrodes on the substrates on the two opposite sides of the liquid crystal medium. Thus the electric field is essentially vertical to the liquid crystal layer. In particular, the first-mentioned displays are used in combination with a TFT (English: thin film transistor) control for displays with a large amount of information and high resolution. For example in "lap-top" and "note-book" computers. Particularly in the case of "desktop" computer monitors, liquid crystal displays of the IPS (English: in-plane switching, for example DE 40 00 451 and EP 0 588 568 ) or alternatively the VAN (vertically aligned nematic) type. VAN displays are a variant of the ECB (electrically controlled birefringence) displays. In a modern variant of the MVA displays (English: multi domain vertically aligned), several domains are stabilized for each driven electrode and a special optical compensation layer is also used. Like the TN displays already mentioned, these displays use an electric field which is vertical to the liquid crystal layer. In contrast to this, IPS displays generally use electrodes on only one substrate, that is to say on one side of the liquid crystal layer, and are therefore characterized by an essential component of the electric field parallel to the liquid crystal layer.

All of these conventional displays a relatively slow shift is common, in particular this is for the always stronger Widespread TV and multimedia applications are not sufficient. This falls in particular compared to the almost ubiquitous cathode ray tubes. Another disadvantage of the known ones used in liquid crystal displays electro-optical effects is the clear viewing angle dependency of the contrast achieved. This is the case in most cases large, that for ads in direct vision mode compensation layers, typically anisotropic Films, some with a complicated structure, must be used.

In the unpublished application DE 10217273.0 light control elements are described in which the mesogenic control medium is in the isotropic phase at the operating temperature.

Switch these light controls particularly fast and have a good viewing angle dependence of the Contrast. However, the drive voltages are for many Applications too high.

The in the not yet disclosed application DE 10217273.0 The electro-optical control elements described require relatively high control voltages. From an application technology perspective, these are generally not advantageous and are too high for many applications. In part, the control voltages can be influenced by appropriate variation of the control media and possibly reduced. However, lowering the control voltages in this way requires the introduction of new polar substances and thus a certain amount of effort and, moreover, the magnitude of the lowering of the control voltages is limited.

The present invention was based on the object of realizing particularly quickly switching light control elements with good viewing angle dependency and in particular with low control voltages. These light control elements should have the smallest possible layer thickness of the control media in order to Elements of FPDs (English: flat panel displays), such as flat screens for computers, can be used. Furthermore, they should be controllable using the simplest possible electrode configuration and have a low operating voltage. In addition, they should have a good contrast with a low viewing angle dependence for use in electro-optical displays.

Thus there is a need for improved ones Light control elements in particular with a reduced control voltage.

This invention

Surprisingly, it was found that, as described below, light control elements described in the unpublished application DE 10217273.0 described light control elements can be significantly improved and that in particular light control elements can be realized with significantly reduced characteristic voltages.

• – ein Substrat oder mehrere Substrate,
• – eine Elektrodenanordnung,
• – mindestens ein Element oder mehrere Elemente zur Polarisation des Lichts und
• – ein Steuermedium, und sind dadurch gekkennzeichnet, dass
  • – das Lichtsteuerelement bei einer Temperatur betrieben wird, bei der das Steuermedium im nicht angesteuerten Zustand in der isotropen Phase vorliegt und dass
  • – die Elektrodenanordnung ein elektrisches Feld mit einer signifikanten Komponente parallel zur Fläche des mesogenen Steuermediums erzeugen kann und dass
  • – die Elektrodenanordnung so gestaltet ist, dass mindestens eine eine der vier folgenden Bedingungen erfüllt ist
  • – die in der Ebene der Steuerschicht einander benachbarten elektrisch leitfähigen Schichten haben einen Abstand von 10 μm oder weniger voneinander,
  • – die leitfähige Schicht oder, wenn mehrere der elektrisch der leitfähigen Schichten vorhanden sind, eine oder mehrere dieser Schichten der Elektrodenstruktur ist bzw. sind erhaben,
  • – die Elektrodenstruktur umfaßt jeweils zwei oder mehrere Schichten die einander überlagern, elektrisch leitend miteinander verbunden sind und gleichzeitig über wesentliche Teile ihrer Fläche voneinander durch eine dielektrische Schicht getrennt sind,
  • – die elektrisch leitfähige Schicht oder, wenn mehrere der elektrisch der leitfähigen Schichten vorhanden sind, eine oder mehrere der leitfähigen Schichten der Elektrodenstruktur ist bzw. sind durch eine feste dielektrische Schicht vom jeweiligen darunterliegenden Substrat getrennt.

The electro-optical light control elements according to the present invention include

• One or more substrates,
• An electrode arrangement,
• - At least one or more elements for polarizing the light and
• - a control medium, and are characterized in that
  • - The light control element is operated at a temperature at which the control medium is in the non-activated state in the isotropic phase and that
  • - The electrode arrangement can generate an electric field with a significant component parallel to the surface of the mesogenic control medium and that
  • - The electrode arrangement is designed so that at least one of the four following conditions is met
  • The electrically conductive layers which are adjacent to one another in the plane of the control layer are at a distance of 10 μm or less from one another,
  • The conductive layer or, if several of the electrically conductive layers are present, one or more of these layers of the electrode structure is or are raised,
  • The electrode structure in each case comprises two or more layers which overlap one another, are electrically conductively connected to one another and at the same time are separated from one another by a dielectric layer over substantial parts of their area,
  • - The electrically conductive layer or, if several of the electrically conductive layers are present, one or more of the conductive layers of the electrode structure is or are separated from the respective underlying substrate by a solid dielectric layer.

 In addition to the low control voltage is in particular the contrast of these displays and its viewing angle dependency excellent and the switching times are very short.

The following is the present Invention closer explained.

Is preferred as the control medium Light control element uses a mesogenic medium. As a mesogenic Media are referred to in the present application as media that have a mesophase that is soluble in a mesophase or induce a mesophase. The mesophase is a smectic or a nematic phase, preferably a nematic phase.

As the preferred medium for investigation the mesogenic properties of the media that have no mesophase the nematic mixture ZLI-4792 from Merck KGaA, Darmstadt, Germany used. The mesogenic media preferably have one from a 10% solution in this mixture extrapolated clearing point of -100 ° C or more, particularly preferred of –50 ° C or more and most preferably from -20 ° C or more.

The light control elements according to the invention contain preferably a mesogenic medium, which at the operating temperature in the isotropic phase. This medium is convenient on or under a substrate.

The control medium is usually located between two substrates. This embodiment is preferred. If the control medium is between two substrates, at least one of these substrates is translucent. The translucent substrate, or the translucent substrates can, for. B. consist of glass, quartz or plastic. If a substrate is used that is not translucent, this can consist, among other things, of a metal or a semiconductor. These media can be used as such or can be present on a carrier, for example a ceramic. If the control medium is a polymeric medium, the use of a second substrate can optionally be dispensed with. Polymer control medium can even be self-supporting. In this case, no substrate is required.

The operating temperature of the light control element is preferably above the transition temperature of the Control medium for the isotropic phase, usually in the range from 0.1 ° to 50 ° above this transition temperature, preferably in the range from 0.1 ° to 10 ° above this transition temperature and particularly preferably in the range from 0.1 ° to 5 ° above this transition temperature.

When a voltage is applied in orientation is induced in the mesogenic medium in the isotropic phase which leads to an optical delay leads, which can be visualized in a known manner. Is preferred applied an inhomogeneous electric field.

The light control elements according to the invention contain at least one element for polarizing light. Also included it prefers another optical element. This further optical Element is either a second element to polarize light, a reflector or a transflector.

The optical elements are arranged that the light as it passes through the mesogenic medium of the light control element both before entering the mesogenic medium and after Leaving the mesogenic medium at least once at least passes through polarizing element.

In a preferred embodiment of the light control element according to the present Invention, the mesogenic medium is between two polarizers, so a polarizer and an analyzer. Two are preferred Linear palaisators used. In this embodiment, the absorption axes are the polarizers are preferably crossed and preferably form one 90 ° angle.

The light control element according to the invention optionally contains one or more birefringent layers. It preferably contains one λ / 4 layer or several λ / 4 layers, preferably a λ / 4 layer. The optical delay the λ / 4 layer is preferably about 140 nm.

The layer thickness (d) of the mesogenic Control medium is preferably 0.1 μm up to 5,000 μm (i.e. 5 mm), particularly preferably 0.5 μm to 1,000 μm (i.e. 1 mm), particularly preferred 1.0 μm to 100 μm and very particularly preferably 3.0 μm up to 30 μm and in particular 3.5 μm up to 20 μm. In a preferred embodiment is the layer thickness of the mesogenic control medium is preferably 0.5 μm to 50 μm, particularly preferably 1.0 μm up to 20 μm and most preferably 1.0 μm up to 8.0 μm.

Object of the present invention are also electro-optical displays, the one or more light control elements according to the invention contain. These electro-optical displays are preferred by means of a active matrix.

The subject of the invention are also electro-optical display systems containing one or more electro-optical according to the invention Show. These electro-optical display systems are preferred to display information, among other things, preferably as a television screen or used as a computer monitor. With the information to be displayed it is preferably digital signals or video signals.

The light control element according to the invention can additionally one or more other common ones optical elements such as birefringent layers (e.g. compensation layers), Diffuser layers, and elements to increase brightness and / or contain the luminous efficacy and / or the viewing angle dependency, these enumeration not concluding is.

The light control elements according to the invention are characterized by a good contrast that is strong and almost predominant depends on the properties of the polarizers used. To the Comparison with conventional ones TN cells become TN cells with an optical delay of 0.50 μm, positive contrast and the absorption axis of the polarizers perpendicular on the preferred orientation of the nematic liquid crystals on the neighboring one Substrate that is not chiral liquid crystals included. Are in the light control elements of the invention and with these conventional ones TN cells using the same polarizers is the contrast the light control elements according to the invention by 40% or more than that of TN cells.

The viewing angle dependency the contrast of the light control elements according to the invention is very good. It is significantly better than that of the known ECB cells. It is more comparable to that of the commercially available IPS advertisements (e.g. from Hitachi and NEC, both Japan) and MVA ads (e.g. from Fujitsu, Japan) observed viewing angle dependency. It is much less than that of conventional TN displays. So one closes Isocontrast curve of a given contrast ratio in the light control elements according to the invention usually an angular range that is more than twice as large, often even is more than three times the size like the corresponding isocontrast curve for the same contrast ratio the TN display.

The switching times of the light control elements according to the invention are very small. They are usually 1 ms or less less, preferably at 0.5 ms or less, particularly preferably at 0.1 ms or less.

The fact is particularly advantageous that when switching between different grayscale both the Switching time for turning it off, as well, particularly surprisingly, for turning it on almost independent of the control voltage used. This represents an essential one advantage over usual Light control elements such as liquid crystal cells, e.g. TN cells.

To investigate the switching behavior in the control of gray levels, the light control elements according to the invention were each switched to different control voltages. Characteristic voltages of the electro-optical characteristic were chosen as end points, for example V ₁₀ , V _{2 0} , V _{3 0} , ... to V _{9 0} . Then there was a switch from a given characteristic voltage to the other voltages and back, for example from V ₁₀ to each of the voltages V ₉₀ , V ₈₀ , V ₇₀ to V _{2 0} . Another one of the characteristic voltages is selected next and on each of the higher characteristic voltages and switched back by this, for example, from V ₂₀ on each of the voltages V _{9 0,} V _80, V ₇₀ to V _30, and so on until the output voltage V ₈₀ from which is switched to V _{9 0} and back. In the case of the light control elements according to the present invention, the switch-on time from the point in time at which the new voltage is switched on until 90% of the respective maximum transmission change has been reached is identical for all of these switching processes in a first approximation.

Electro-optical displays according to the present Invention contain one or more light control elements according to the invention. In a preferred embodiment, these are activated Matrix driven.

In another preferred embodiment the light control elements according to the invention in so-called "field sequential mode ". The switching elements synchronized with the control one after the other with different colored light illuminated. To generate the pulsed colored light, for example a color wheel ("color wheel "), strobe lamps or flash lamps.

Electro-optical displays according to the present Invention can especially if they're for TV screens, Computer monitors or the like a color filter is used to display colored images contain. This color filter expediently consists of a mosaic of filter elements of different colors. Here is more typical Assign each element of the color filter mosaic to each electro-optical switching element assigned to a color.

The light control elements according to the invention contain an electrode structure which has an electrical field with a significant Component generated parallel to the layer of the mesogenic medium. This Electrode structure can be in the form of interdigital electrodes accomplished his. It can be in the form of combs or Executed ladders his. Also executions in the form of layered "H" s and double "T" s or "I" s are advantageous. The electrode structure is advantageously located on only one side of the mesogenic medium, when using at least one substrate, preferably between them and the mesogenic medium. The electrode structure is preferably located in at least two different levels, both on one Side of the mesogenic control medium, this applies in particular if the electrode structure is overlapping Contains substructures. These substructures are advantageously made by a dielectric Layer separated from each other. If the substructures refer to the opposite "Lay-Out" can be selected on the sides of an insulation layer, that allows the realization of capacitors. This is particularly so advantageous when controlling displays by means of an active matrix. Such active matrix displays use a matrix of each Control elements assigned to light control elements with a non-linear one Current-voltage characteristic, such as. B. TFTs or MIM- (English: metal insulator metal) diodes.

An essential aspect of the present Invention consists in the configuration of the electrode structure of the electro-optical according to the invention Switching elements. Various embodiments are possible here. in the Following are the preferred embodiments of the electrodes the light control elements according to the invention if necessary, using the corresponding illustrations described.

The structure of light control elements with a mesogenic control material is in principle in DE 102 172 73.0 described. Here he is briefly based on the 1 clarified.

The figure shows schematically in cross section the structure of a switching element or part of a switching element DE 102 172 73.0 , Between the inner surfaces of the substrates ( 1 ) and ( 1' ) is the control medium ( 2 ). On the inner surface of one substrate ( 1 ) are the two electrodes ( 3 ) and ( 4 ) of the electrode structure, which can be applied with different potentials. "Vop" denotes the voltage, charge or current source. The lines emanating from Vop symbolize the electrical leads to the electrodes.

The electrodes can be made of transparent material exist, such as B. Indium Tin Oxide (ITO). In this case it can advantageous and possibly necessary be a part or parts of the light control element by means of a cover black mask. This allows areas where the electrical Field is not effective to shield and so improve the contrast. The electrodes can but also consist of opaque material, usually made of metal, e.g. made of chrome, aluminum, copper, silver or gold, preferably made of chrome. In this case, the use of a separate black mask may be omitted.

The electric field used is prefers an inhomogeneous field.

It has been found that the lateral spacing of the electrodes, which can be acted upon with different potentials, from one another has a strong influence on the characteristic voltages of the light control elements. The required control voltage decreases as the distance decreases. However, when the distance becomes smaller, the opening ratio of the light control element also becomes smaller and the brightness speed decreases. The electrodes are preferably at a distance from one another in the range from 0.5 μm to 100 μm, preferably in the range from 1 μm to 20 μm, particularly preferably in the range from 1 μm to 15 μm, very particularly preferably in the range from 2 μm to 12 µm and most preferably in the range of 3 µm to 11 µm. The distance between the electrodes is preferably 19 μm or less, particularly preferably 15 μm or less, very particularly preferably 10 μm or less and particularly preferably 9 μm or less.

The width of the electrodes in the Direction to the neighboring electrodes, which has different potentials can be is less critical than the distance between the electrodes in this direction. He has almost no influence on the characteristic voltages of the light control elements. With increasing However, the width of the electrodes becomes the opening ratio of the light control element smaller and the brightness decreases, especially when the electrodes from opaque Material. In contrast, the width of the electrodes decreases their electrical resistance too. The electrodes preferably have one Width in the range of 0.5 μm up to 30 μm, preferably in the range of 0.5 μm up to 20 μm, particularly preferably in the range from 0.7 μm to 19 μm, very particularly preferred in the range of 1 μm up to 9 μm and most preferably in the range of 1.5 µm to 6 µm.

In the first particularly preferred embodiment (embodiment A) the electrodes are raised. Here sublime means that the electrodes have a layer thickness that is not compared to the Layer thickness of the control layer is negligible. The layer thickness is preferably the electrodes each 5% or more, preferably 10% or more, particularly preferably 20% or more of the distance between the substrates, that is, the layer thickness of the control medium at the locations of the cell where there are no electrodes.

In this embodiment with the sublime So electrodes have a certain thickness compared to the Layer thickness of the mesogenic medium should not be neglected. In this case, the electrode structure can have different topographies to have. The electrode structure can be characterized by a significant Proportion of the total thickness of the layer of the mesogenic control medium extend. The maximum height of the electrode layer or the electrode layer, however, is significantly smaller than the thickness of the mesogenic Medium. Is preferably The relationship 1: 3 or less, particularly preferably 1:10 or less and entirely especially 1:50 or less. In some cases the thickness of the electrode layer across from the thickness of the mesogenic medium, then that is relationship preferably 1: 100 or less.

However, an embodiment is also preferred in which the electrode arrangement of the light control element is designed in this way are that they are over a predominant one Proportion of the layer thickness of the mesogenic control medium, preferably over more than 60%, preferably essentially over the entire layer thickness of the mesogenic control medium, particularly preferably over 80% or more, and most preferably over 90% or more.

In a preferred embodiment is the lower limit of the layer thickness of the electrodes 0.5 μm, especially preferably 1 μm and very particularly preferably 2 μm and the upper limit is preferably 10 μm, preferably 5 μm and entirely particularly preferably 3 μm.

The 2 to 6 schematically show in cross section the structure for five different embodiments of switching elements according to the invention with raised electrodes according to the preferred embodiment (A).

At the in 2 In the embodiment shown, the electrodes are designed similarly to that in FIG 1 shown embodiment. The electrodes ( 3 ) and ( 4 ) have a rectangular or almost rectangular cross section. However, the electrodes have a thickness that is different from the layer thickness (d ( 2 )] the control layer ( 2 ), or compared to the characteristic layer thickness, should not be neglected, for example typically in the range from 0.5 μm to 3 μm, preferably in the range from 1 μm to 2 μm.

At the in 3 shown embodiment are the electrodes ( 3 ) and ( 4 ) similar to the one in 2 shown embodiment. However, these electrodes extend over the entire thickness [d ( 2 )] the control layer ( 2 ).

At the in 4 shown embodiment are the electrodes ( 3 ) and ( 4 ) designed similarly to the one in 2 shown embodiment. However, the layer thickness of the electrodes ( 3 ) and ( 4 ) not constant, but depending on the location. The electrodes have a triangular cross section.

At the in 5 shown embodiment are the electrodes ( 3 ) and ( 4 ) designed similarly to that in 4 shown embodiment with the location-dependent layer thickness. However, these electrodes each consist of two superimposed layers ( 3 ) and ( 3 ' ) such as ( 4 ) and ( 4 ' ), of which the upper ( 3 ' ) respectively. ( 4 ' ) covers a smaller area of the switching element than the corresponding lower layer ( 3 ) respectively. ( 4 ).

At the in 6 shown embodiment are the electrodes ( 3 ) and ( 4 ) again similar to the one in 2 shown embodiment. However, the electrodes ( 3 ) and ( 4 ) here a circular cross section and are shown as waveguides. However, you can also use other rounded ones Have cross sections and can be designed, for example, in the form of a solid wire or as a conductively coated cylinder of a non-conductive or non-conductive material.

Here are also embodiments comprises where a pair of electrodes with a common potential flank an electrode with a different potential. or deal with at least a pair of electrodes applied with the other potential become or can become alternate. Here you can the electrodes are in one plane or in different planes. The electrodes which have the same potential are preferably located or can be or can be acted on with the same potential, in the same level.

In a preferred embodiment the light control elements according to the invention where the conductive Layers of the electrodes are raised, are the neighboring ones Electrodes of the electrode structure, at least partially, are preferred essentially, particularly preferably largely horizontally a solid dielectric layer insulated from each other.

In another embodiment are the substructures of the electrode structure on the two opposite Sides of the mesogenic medium. In this case, the corresponding ones stand Parts of the electrodes are not perpendicular to each other, but are against each other laterally offset so that a component of the electrical field arises parallel to the layer of the mesogenic medium.

In a particularly preferred embodiment (embodiment B) of the present invention, the electrode structure is designed such that the electrodes are at a distance above their respective substrate and preferably over a substantial part of their area, preferably over the predominant part of their area and particularly preferably almost are insulated against it over their entire area or over their entire area. For this purpose, the electrodes are preferably formed on a solid dielectric. This is exemplified in 7 . 9 and 11 to 13 shown. A solid insulator, as described below, is preferably used as the solid dielectric. The solid dielectric is particularly preferably designed as a layer or as a platform.

• – der wesentliche Teil: bevorzugt 20 % oder mehr, besonders bevorzugt 30 % oder mehr und ganz besonders bevorzugt 40 % oder mehr,
• – der überwiegende Teil: bevorzugt 55 % oder mehr, besonders bevorzugt 60 % oder mehr und ganz besonders bevorzugt 70 % oder mehr,
• – nahezu gesamt: bevorzugt 80 % oder mehr, besonders bevorzugt 90 % oder mehr und ganz besonders bevorzugt 95 % oder mehr, und
• – gesamt: bevorzugt 98 % oder mehr, besonders bevorzugt 99 % oder mehr und ganz besonders bevorzugt 100 %.

In connection with the proportions of the areas of the electrode structure means

• The essential part: preferably 20% or more, particularly preferably 30% or more and very particularly preferably 40% or more,
• The predominant part: preferably 55% or more, particularly preferably 60% or more and very particularly preferably 70% or more,
• - almost total: preferably 80% or more, particularly preferably 90% or more and very particularly preferably 95% or more, and
• - Total: preferably 98% or more, particularly preferably 99% or more and very particularly preferably 100%.

The 7 shows schematically in cross section the structure for a preferred embodiment of embodiment (B) of switching elements according to the invention. Here the electrodes are designed similar to the one in 1 shown embodiment. However, the electrodes are not located directly on the surface of the substrate, but rather on a solid insulating layer ( 5 ) respectively. ( 6 ) of a certain thickness, for example typically in the range from 1 μm to 2 μm. Here, the electrode arrangement is configured such that the electrode pairs of a picture element are separated from the associated substrate by a dielectric. This embodiment is preferred because it enables the light control elements and the electro-optical displays to be easily manufactured since the electrodes are only on one substrate. With an appropriate choice of the thickness of the solid insulating layer among the conductive layers of the electrodes, a great effect on the drive voltages can be achieved here.

In this preferred embodiment (B), the conductive layers of the electrode structures are raised above the surface of the adjacent substrate. In this embodiment, there is a solid, insulating layer between the respective substrate and the adjacent conductive layer. This solid, insulating layer can consist of glass, quartz, one or more inorganic layers, such as SiO ₂ or SiN, organic polymers or the like.

In a preferred embodiment In the present invention, the insulating layer is as raised Parts of the substrate are realized e.g. in the form of a pedestal. This embodiment can easily and preferably be obtained by attaching the substrate the places where no pedestal is desired is correspondingly deep etched becomes. If necessary, the respective conductive layer serve the electrode structure as a mask during the etching or both layers can be etched through the same mask in one step. In another embodiment the solid, insulating layer on the substrate in known Structured or unstructured applied or deposited over the surface and if necessary subsequently structured.

The layer thickness is preferably solid, insulating layer in the range from 0.1 μm to 10 μm, particularly preferably in the range of 0.2 μm up to 7 μm, very particularly preferably in the range from 0.4 μm to 5 μm and particularly preferred in the range of 0.5 μm up to 4 μm.

In a very special preferred embodiment (embodiment C) the present invention consists of the electrodes of the electrode structure, that have the same potential, from two or more electrically conductive Layers. These layers are one above the other in the cell of the switching element arranged and preferably over a substantial part of their area, preferably over the vast majority Part of their area and particularly preferably almost over their entire area or about their entire area separated from each other by a dielectric and electrically isolated. If the conductive Layers over in the light control 100% of their area is insulated, they will be outside the light control electrically conductive with each other or with a voltage, charge or power source connected.

In a preferred embodiment In the present invention there is at least one conductive layer each the electrode structure on one of the substrates. In this embodiment the layer of the control medium forms the dielectric between the Electrode layers.

In another preferred embodiment are each two or more electrically conductive layers of the electrode structure each separated by a solid dielectric.

The 8th shows schematically in cross section the structure for a preferred embodiment of the embodiment (C) of switching elements according to the invention with an electrode structure in which the electrodes consist of two layers, each of which is located on one of the substrates. Here the electrodes are designed in such a way that they 3 ) on the first substrate ( 1 ) with a first potential, a second electrode ( 3 ^` ) on the second substrate ( 1' ) there that can be applied with the same potential. There is also the electrode ( 4 ) on the first substrate, to which the second potential can be applied, a second electrode ( 4 ' ) on the second substrate, which can also be acted upon by the second potential. The pairs of electrodes ( 3 ) and ( 3 ' ) such as ( 4 ) and ( 4 ' ) opposite each other. This embodiment is preferred because it allows a very large reduction in the characteristic voltages and the effect achieved does not depend on other parameters, such as the material and the layer thickness of the solid dielectric used.

The electrode structure preferably has each have two pairs of electrodes, one of which is assigned to the other each with at least one pair of electrodes associated with each other the same electrical potential are or will be applied can.

In this embodiment, there is the possibility that the conductive layers of the electrodes assigned to one another in pairs on the opposite substrates (compare 8th and 9 ) or on the same substrate (compare e.g. 10 and 11 ) exhibit.

The electrodes preferably consist the electrode arrangement in this embodiment (C), as well as in the Developments of the embodiment (B) two or more conductive interconnected layers.

Here are the individual layers of the electrodes essentially each

• - about their the whole area separated from each other by a dielectric
• - equal area and
• - lying congruently one above the other.

The described embodiments can can also be combined with each other. So z. B. in the last described, very particularly preferred embodiment of the embodiment (C), the first conductive layer facing the substrate by a solid dielectric separated from each other, two or more each electrically conductive Layers of the electrode structure, as described in the second, preferred embodiment, separated from the respective substrate by a solid dielectric layer his.

The 9 to 13 schematically show in cross section the structure of various embodiments of switching elements according to the invention according to a further preferred embodiment of the present invention.

9 shows an embodiment that a combination of in the 7 and 8th illustrated embodiments. In contrast to in 7 shown training form are not only on the substrate with the surface ( 1 ) raised electrodes (( 3 ) and ( 4 ) on solid insulating layers ( 5 ) and ( 6 ) educated. Rather, as in the 8th illustrated embodiment also on the surface of the opposite substrate ( 1' ) Electrodes ( 3 ' ) and ( 4 ' ) educated. Like the corresponding electrodes on the first substrate, these electrodes are protected by solid insulating layers ( 5 ' ) and ( 6 ' ) from the surface ( 1' ) lifted.

In the 10 the electrodes are similar to the one in 7 shown embodiment. However, the electrodes are as shown in FIG 8th shown embodiment, each of two layers ( 3 ) and ( 3 ' ), respectively. ( 4 ) and ( 4 ' ), which can be acted upon in pairs with the same potential. In contrast to that in 8th shown embodiment, the two pairs of conductive layers of the electrode structure ( 3 ) and ( 3 ' ), respectively. ( 4 ) and ( 4 ' ) but not through the dielectric control layer ( 2 ) separated from each other, but each time by a solid insulating layer ( 5 ) respectively. ( 6 ).

In the 11 the electrodes are similar to the one in 10 shown execution form. However, here, as with the in 7 shown embodiment, in each case the first layers of the electrode structures ( 3 ) respectively. ( 4 ) through a solid insulating layer ( 5 ) respectively. ( 6 ) separated from the substrate (lifted off). The two layers of the electrode structure that can be applied with the same potential ( 3 ) and ( 3 ' ), respectively. ( 4 ) and ( 4 ' ), as in the in 10 described embodiment, in each case by a solid insulating layer, here ( 5 ' ) respectively. ( 6 ' ), separated from each other.

In the 12 the electrodes of the electrode structure consist of four conductive layers ( 3 ) to ( 3 ''' ) respectively. ( 4 ) to ( 4 ''' ). Two of these four layers are located on the same substrate. Layers ( 3 ) and ( 3 ' ) such as ( 4 ) and ( 4 ' ) are on the substrate with the surface ( 1 ) and ( 3 '' ) and ( 3 ''' ) such as ( 4 '' ) and ( 4 ''' ) are on the substrate with the surface ( 1' ). Of these layers, the respective substrate ( 1 ) respectively. ( 1' ) adjacent layer ( 3 ) and ( 4 ) respectively. ( 3 '' ) and ( 4 '' ) through a solid insulating layer ( 5 ) and ( 6 ) respectively. ( 5 ' ) and ( 6 ' ) Cut. The two conductive layers on the same substrate [( 3 ) and ( 3 ' )] and [( 4 ) and ( 4 ' )] such as [( 3 '' ) and ( 3 ''' )] and [( 4 '' ) and ( 4 ''' )], are also due to solid insulating layers ( 5 ' ) and ( 6 ' ) such as ( 5 ''' ) and ( 6 ''' ) separated from each other.

In the 13 consist of the electrodes of the electrode structure, as in the one in the illustration 12 shown embodiment, each of four conductive layers ( 2 ) to ( 2 ''' ) respectively. ( 3 ) to ( 3 ''' ). Here, however, the alternating sequence of conductive layers and insulating layers extends over the entire layer thickness of the control layer. This will cause the inner pairs of conductive layers ( 2 ' ) and ( 2 ''' ) such as ( 3 ' ) and ( 3 ''' ) also through solid insulating layers ( 5 '''' ) respectively. ( 6 '''' ) separated from each other.

Between the electrically conductive layers of the electrodes of the electrode structure, the layer or parts of the layer of the mesogenic control medium can be used as a dielectric (compare, for example, 8th and 9 ) or a (compare 10 and 11 ) or several solid dielectric layers.

The conductive layer, or in the case that the electrodes comprise two or more conductive layers, the respective lower conductive layer of the electrodes, can be arranged on an insulating layer above one of the substrates (compare 7 . 9 . 11 . 12 and 13 ).

In a preferred embodiment of the present invention, each electrode contains at least four conductive layers (compare 12 and 13 ), wherein at least two of the conductive layers are each on a substrate and can or can be acted on with different potential. In this embodiment, each of these two electrodes is assigned at least one further electrode which is or can be acted upon with the same potential. Each of these at least one further electrode, which is assigned to each of the electrodes of the electrode pairs, is separated from the latter by a dielectric.

It is possible to use the conductive layers of the electrodes both in the preferred embodiment (B) and in the particularly preferred embodiment (C) as in the embodiment (A) described to perform sublime.

In embodiment (C), two of the superimposed conductive electrode layers to which the same potential is applied can also be particularly preferred, both separated from one another by the dielectric control layer and at the same time by a solid dielectric layer from the respective underlying substrate or, if appropriate, one below it lying further electrically conductive layer must be separated (see 9 ). This embodiment is preferred because it allows the drive voltage to be compared to that in FIGS 7 and 8th shown embodiments to further reduce.

According to the available results, the strength of the electro-optical effect observed depends on the layer thickness of the isotropic control medium. With small layer thicknesses in the range of less than one micrometer, the necessary control voltage decreases with increasing layer thickness. This effect persists up to a characteristic layer thickness (d _c ) at which saturation occurs. A further increase in the layer thickness to values above this characteristic layer thickness does not lead to any further significant improvement, that is to say a decrease in the characteristic tensions. The characteristic layer thickness is typically in the range from 0.5 μm to 10 μm, mostly in the range from 1.0 μm to 5.0 μm. For most practically relevant cases, values from approx. 2 μm to 3 μm are to be assumed, in particular a value of approx. 3 μm.

The layer thickness of the isotropic control layer is preferably at least in the light control elements of embodiment (A) as big as the characteristic layer thickness.

In the embodiments (B) and (C), the layer thickness is the isotropic control layer prefers twice the characteristic Layer thickness or more. This preferred lower limit of layer thickness of the control medium applies to the case that in the embodiment (B) the electrode structure comprises two layers each can be or can be acted upon with the same potential as well for the Case that in the embodiment (C) the electrode structure is exactly an electrically conductive layer contains which is or can be exposed to the given potential.

The embodiment (C) with exactly one conductive layer in the electrode structure leads to similar results as the embodiment (B). With an increase in the thickness of the solid, insulating layer between the substrate and the conductive layer, the characteristic voltages decrease to a saturation which occurs when the layer thickness of the solid, insulating layer has the value of the characteristics layer thickness reached as long as the total layer thickness of the control layer is large enough. In this embodiment, the height of the insulating layer under the first conductive layer facing the substrate is preferably equal to or greater than the characteristic layer thickness. The thickness of the remaining part of the control layer above the conductive layer of the electrode structure is also equal to or larger than the characteristic layer thickness, so preferred lower limit of the total layer thickness of the control layer in this embodiment, as in embodiment (B), is twice as large the characteristic layer thickness. The optimal effect is achieved if the conductive layer is in the middle, or almost in the middle, of the thickness of the control layer and extends in the direction of each of the substrates by the characteristic layer thickness or more.

Are several conductive layers on top of each other used, each by a solid insulating layer from each other are separated, so increased the lower limit of the layer thickness of the control medium with each other additional conductive Layer twice the characteristic layer thickness.

The mesogenic media according to the present Endings preferably have a nematic phase. However, it can media are also used in which the temperature range of nematic phase is so narrow that practically a transition from the crystalline phase or from the smectic phase to the Isotropic phase takes place.

The clearing point of a nematic Phase-containing mesogenic media is preferably in the range from -20 ° C to 80 ° C, especially preferably in the range of 0 ° C up to 60 ° C and very particularly preferably in the range from 20 ° C to 60 ° C. For backlit displays lies the clearing point preferably in the range of 10 ° C up to 70 ° C and particularly preferably in the range from 30 ° C to 50 ° C.

The nematic phase is preferred stable to –10 ° C, especially preferably down to –30 ° C and whole particularly preferred down to -40 ° C.

The mesogenic media according to the present Invention show in the nematic phase at a temperature of 4 degrees below the clearing point preferably birefringence (Δn) of 0.090 or more, preferably 0.100 or more, particularly preferred 0.150 or more, most preferably 0.200 or more on. The value of the birefringence is for the application according to the invention almost unlimited. In practice, however, it is usually 0.500 or less and usually 0.450 or less. The value of birefringence the media of the invention is here in the nematic phase at a temperature of 4 ° below of the clearing point measured. If the medium is not stable nematically at this temperature or at least up to this temperature in the nematic phase unterkühlbar so the birefringence of a mixture of 15% of the medium and 85% of the nematic mixture ZLI-4792 from Merck KGaA determined at 20 ° C and from the change across from the mixture ZLI-4792 extrapolated to the value of the pure medium.

The mesogenic media according to the present Invention preferably have a dipole moment of 4 Debye or more, particularly preferred from 6 Debye or more and particularly preferred from 8 Debye or more.

For the light control elements according to the present Can end Both mesogenic control media are used in the mesophase have a positive dielectric anisotropy (Δε) as well which have negative dielectric anisotropy. Prefers mesogenic control media are used, the one in the mesophase have positive dielectric anisotropy (Δε).

If the mesogenic control media a have positive dielectric anisotropy, this has at 1 kHz and a temperature of 4 ° below of the clearing point, preferably in the nematic phase, preferably 15 or more, particularly preferably 30 or more and very particularly preferred 45 or more. Does the medium have no nematic phase or does it lie at a temperature of 4 ° below of the clearing point not in the nematic phase before, so its dielectric Anisotropy like birefringence by extrapolation of the values a mixture of 15% determined in the mixture ZLI-4792.

If the mesogenic control media a have negative dielectric anisotropy, it has a value of preferably -5 or less, particularly preferably -7 or less and very particularly preferably -10 Or less.

Control media are particularly preferred with a positive dielectric anisotropy.

The mesogenic media according to the present Endings preferably consist of two to 40 compounds, especially preferably from five up to 30 compounds and very particularly preferably from seven to 25 connections.

• – eine Komponente A bestehend aus einer oder mehreren Verbindungen mit einer sehr stark positiven dielektrischen Anisotropie von 30 oder mehr,
• – optional eine Komponente B bestehend aus einer oder mehreren Verbindungen mit einer stark positiven dielektrischen Anisotropie von 10 bis < 30,
• – optional eine Komponente C bestehend aus einer oder mehreren Verbindungen mit einer moderat positiven dielektrischen Anisotropie von > 1,5 bis < 10,
• – optional eine Komponente D bestehend aus einer oder mehreren dielektrisch neutralen Verbindungen mit einer dielektrischen Anisotropie im Bereich von –1,5 bis +1,5 und
• – gegebenenfalls optional eine Komponente E bestehend aus einer oder mehreren Verbindungen mit einer negativen dielektrischen Anisotropie von weniger als –1,5.

The mesogenic media according to the invention with positive dielectric anisotropy according to the present invention preferably contain

• A component A consisting of one or more compounds with a very strongly positive dielectric anisotropy of 30 or more,
• Optionally a component B consisting of one or more compounds with a highly positive dielectric anisotropy from 10 to <30,
• - Optionally, a component C consisting of one or more compounds with a moderately positive dielectric anisotropy from> 1.5 to <10,
• Optionally a component D consisting of one or more dielectrically neutral compounds with a dielectric anisotropy in the range from -1.5 to +1.5 and
• - optionally, a component E consisting of one or more compounds with a negative dielectric anisotropy of less than -1.5.

worin
R¹ Alkyl, Alkoxy, bevorzugt n-Alkyl, n-Alkoxy, jeweils mit 1 bis 7 C-Atomen, Alkenyl, Alkenyloxy, Alkinyl oder Alkoxyalkyl jeweils mit 2 bis 7 C-Atomen,

Z¹¹ und Z^{1 2} jeweils voneinander unabhängig, eine Einfachbindung, -CO-O-, trans -CH=CH-, -CH=CF-, -CF=CH-, -CF=CF-, -CH=CH-CO-O-, -CF=CF-CO-O-, -CF=CH-CO-O-, -CH=CF-CO-O-, -CF₂-O-, -O-CF₂- oder -C≡C- oder eine Kombination von zwei oder mehreren dieser Gruppen,
X¹ F, -OCF₃, -CF₃, -OCF_ZH, Cl, CN, -C≡C-CN oder NCS, bevorzugt CN, -C≡C-CN oder NCS und
n¹ 0 oder 1 bedeuten,
wobei
im Fall X¹ = F die Phenylringe insgesamt mindestens 2, bevorzugt mindestens 3, weitere F-Atome tragen,
im Fall X¹ = -OCF₃, -CF₃, -OCF₂H oder Cl die Phenylringe insgesamt mindestens 1 weiteres F-Atom, bevorzugt mindestens 2 weitere, F-Atome tragen und
im Fall X¹ = CN, -C≡C-CN oder NCS die Phenylringe bevorzugt mindestens 1 weiteres F-Atom tragen.Component A of these media preferably contains one or more compounds of the formula I and particularly preferably consists predominantly and very particularly preferably almost completely of one or more compounds of the formula I,

wherein
R ^{1 is} alkyl, alkoxy, preferably n-alkyl, n-alkoxy, each having 1 to 7 C atoms, alkenyl, alkenyloxy, alkynyl or alkoxyalkyl each having 2 to 7 C atoms,

Z ¹¹ and Z ^{1 2} are each independent of one another, a single bond, -CO-O-, trans -CH = CH-, -CH = CF-, -CF = CH-, -CF = CF-, -CH = CH-CO -O-, -CF = CF-CO-O-, -CF = CH-CO-O-, -CH = CF-CO-O-, -CF ₂ -O-, -O-CF ₂ - or -C ≡C- or a combination of two or more of these groups,
X ¹ F, -OCF ₃ , -CF ₃ , -OCF _Z H, Cl, CN, -C≡C-CN or NCS, preferably CN, -C≡C-CN or NCS and
n ¹ denotes 0 or 1,
in which
in the case X ¹ = F, the phenyl rings carry a total of at least 2, preferably at least 3, further F atoms,
in the case of X ¹ = -OCF ₃ , -CF ₃ , -OCF ₂ H or Cl, the phenyl rings carry a total of at least 1 further F atom, preferably at least 2 further F atoms, and
in the case of X ¹ = CN, -C≡C-CN or NCS the phenyl rings preferably carry at least 1 further F atom.

worin die Parameter die oben unter Formel I gegebene Bedeutung haben.The media according to the invention preferably contain one or more compounds selected from the group of compounds of the formulas I-1 to I-7 and / or one or more compounds selected from the group of compounds of the formulas II-1 to II-5, which are also sub-formulas of Formula 1.

wherein the parameters have the meaning given above under formula I.

worin die Parameter die oben unter Formel I gegebene Bedeutung haben.The media according to the invention particularly preferably comprise one or more compounds selected from the group of the compounds of the formulas I-1a to I-1e, I-2a to I-2c, I-3a to I-3c, I-4a to I-4c, I-5a to I-5c, I-6a to I-6c and I-7a to I-7c and / or one or more compounds selected from the group pe of the compounds of the formulas II-1a to II-1c, II-2a to II-2c, II-3a, II3b, II-3a, II-4b, II-5a and II-5b.

wherein the parameters have the meaning given above under formula I.

worin
n eine ganze Zahl von 0 bis 7, bevorzugt 1 bis 7,
m eine ganze Zahl von 0 bis 5
n+m eine ganze Zahl von 0 bis 7, bevorzugt von 1 bis 5
bedeuten.The compounds of the formulas I-1a to I-1e are preferably selected from the group of the compounds of the formulas I-1a-1 to I-1a-6, I-1b-1 to I-1b-9, I-1c-1 to I-1c-9, I-1d-1 to I-1d-5 and I-1e-1 and I-1e-2.

wherein
n is an integer from 0 to 7, preferably 1 to 7,
m is an integer from 0 to 5
n + m is an integer from 0 to 7, preferably from 1 to 5
mean.

worin
n eine ganze Zahl von 0 bis 7, bevorzugt von 0 bis 5 und besonders bevorzugt von 1 bis 5,
m eine ganze Zahl von 0 bis 5 und
n+m eine ganze Zahl von 0 bis 7, bevorzugt von 1 bis 5
bedeutet.The compounds of the formulas I-2a to I-2c are preferably selected from the group of the compounds of the formulas I-2a-1 to I-2a-5, I-2b-1 to I-2b-9 and I-2c-1 to I-2c-17.

wherein
n is an integer from 0 to 7, preferably from 0 to 5 and particularly preferably from 1 to 5,
m is an integer from 0 to 5 and
n + m is an integer from 0 to 7, preferably from 1 to 5
means.

worin n eine ganze Zahl von 0 bis 7, bevorzugt von 0 bis 5 und besonders bevorzugt von 1 bis 5 bedeutet.The compounds of the formulas I-3a to I-3c are preferably selected from the group of the compounds of the formulas I-3a-1 to I-3a-4, I-3b-1 to I-3b-4 and I-3c-1 to I-3c-4.

wherein n is an integer from 0 to 7, preferably from 0 to 5 and particularly preferably from 1 to 5.

worin n eine ganze Zahl von 0 bis 7, bevorzugt von 0 bis 5 und besonders bevorzugt von 1 bis 5 bedeutet.The compounds of the formulas I-4a to I-4c are preferably selected from the group of the compounds of the formulas I-4a-1 to I-4a-3, I-4b-1 to I-4b-3 and I-4e-1 to I-4c-3.

wherein n is an integer from 0 to 7, preferably from 0 to 5 and particularly preferably from 1 to 5.

worin n eine ganze Zahl von 0 bis 7, bevorzugt von 0 bis 5 und besonders bevorzugt von 1 bis 5 bedeutet.The compounds of the formulas I-5a to I-5c are preferably selected from the group of the compounds of the formulas I-5a-1b to I-5a-3, I-5b-1 to I-5b-3 and I-5c- 1 to I-5a-1 I-5ca-3.

wherein n is an integer from 0 to 7, preferably from 0 to 5 and particularly preferably from 1 to 5.

worin n eine ganze Zahl von 0 bis 7, bevorzugt von 0 bis 5 und besonders bevorzugt von 1 bis 5 bedeutet.The compounds of the formulas I-6a to I-6c are preferably selected from the group of the compounds of the formulas I-6a-1 to I-6a-3, I-6b-1 to I-6a-3 and I-6c-1 to I-6a-3.

wherein n is an integer from 0 to 7, preferably from 0 to 5 and particularly preferably from 1 to 5.

worin n eine ganze Zahl von 0 bis 7, bevorzugt von 0 bis 5 und besonders bevorzugt von 1 bis 5 bedeutet.The compounds of the formulas I-7a to I-7c are preferably selected from the group of the compounds of the formulas I-7a-1 and I-7a-2, I-7b-1 and I-7b-2 and I-7c-1 and I-7c-2.

wherein n is an integer from 0 to 7, preferably from 0 to 5 and particularly preferably from 1 to 5.

worin n eine ganze Zahl von 0 bis 7, bevorzugt von 0 bis 5 und besonders bevorzugt von 1 bis 5 bedeutet.The media according to the invention particularly preferably comprise one or more compounds selected from the group of the compounds of the formulas II-1c-1, II-2c-1, II-3b-1, II-4b-1 and II-5b-1.

wherein n is an integer from 0 to 7, preferably from 0 to 5 and particularly preferably from 1 to 5.

The media according to the invention preferably contain one or more compounds selected from the group of compounds of the formulas I-1 to I-7 and one or more compounds selected from the group of compounds of the formulas II-1 to II-5.

The following table are some Examples of compounds of the particularly preferred formulas compiled, which are particularly suitable for the production of media according to the invention.

Table 1: Examples of preferred compounds

Table 1 (continued): Examples of preferred compounds

Table 1 (continued): Examples of preferred compounds

Table 1 (continued): Examples of preferred compounds

Table 1 (continued): Examples of preferred compounds

The mesogenic media according to the present Invention with positive dielectric anisotropy exist particularly preferably predominantly and very particularly preferably almost completely from component A.

In a preferred embodiment contain the mesogenic media according to the present invention with positive dielectric anisotropy one or more components selected from the group of components B to D, preferably selected from the group of components B and D.

• – eine Komponente A' bestehend aus einer oder mehreren Verbindungen mit einer stark negativen dielektrischen Anisotropie von –5 oder weniger,
• – optional eine Komponente B' bestehend aus einer oder mehreren Verbindungen mit einer moderat negativen dielektrischen Anisotropie von –1,5 bis < –5,
• – optional eine Komponente C' bestehend aus einer oder mehreren dielektrisch neutralen Verbindungen mit einer dielektrischen Anisotropie von –1,5 bis +1,5 und
• – gegebenenfalls eine Komponente D' bestehend aus einer oder mehreren Verbindungen mit einer positiven dielektrischen Anisotropie von mehr als 1,5.

Component D of these media preferably contains one or more compounds. The mesogenic media with negative dielectric anisotropy according to the present invention preferably contain

• A component A 'consisting of one or more compounds with a strongly negative dielectric anisotropy of -5 or less,
• Optionally a component B 'consisting of one or more compounds with a moderately negative dielectric anisotropy from -1.5 to <-5,
• - Optionally a component C 'consisting of one or more dielectrically neutral compounds with a dielectric anisotropy of -1.5 to +1.5 and
• - optionally a component D 'consisting of one or more compounds with a positive dielectric anisotropy of more than 1.5.

The mesogenic medium according to the present invention can contain further additives and chiral dopants in conventional concentrations. The total concentration of these further constituents is in the range from 0% to 10%, preferably in the range from 0.1% to 6%, based on the total mixture. The concentrations of the individual of these compounds are in the range from 0.1 to 3%. The concentration of these compounds and similar components of the mixture are given when specifying the concentration ranges the other components of the mixture are not taken into account.

The media are made in the usual way obtained from the connections. The connections are expedient which are used in smaller quantities in larger quantities used connections solved. Will the temperature during of the mixing process the clearing point the predominant Component increased, can completeness the dissolution can be easily observed. However, the media according to the invention can can also be made in other ways. So through the effort of premixes. Homolog mixtures can be used as premixes and / or eutectic mixtures are used. The premixes can but also be usable media itself. This is in so-called two-bottle or multi-bottle systems (English: two-bottle or multi-bottle systems) the case.)

In the present application, unless explicitly stated otherwise, the following.

Dielectric positive connections have a Δε> 1.5, dielectric neutral connections have a Δε in the range –1.5 ≤ 5 Δε ≤ 1.5 and dielectric negative compounds have a Δε <-1.5. The The same definitions also apply to components of mixtures and for Mixtures.

The dielectric anisotropy Δε of the connections is at 1 kHz and 20 ° C by extrapolating the values of a 10% solution of the respective compound in a host mixture on a portion of the respective compound determined by 100%. The capacities of the test mixtures are both in a cell with homeotropic, as well as in a cell with a homogeneous edge orientation. The layer thickness of both cell types is approximately 20 μm. For measurement becomes a square wave with a frequency of 1 kHz and an effective voltage (rms, English: root mean square) of typically 0.2 V to 1.0 V used. In any case, the voltage used is lower than the capacitive threshold of the mixture examined in each case.

For the mixture ZLI-4792 and dielectric positive connections for dielectric neutral, as well as for dielectric negative compounds, the mixture ZLI-3086, both from Merck KGaA, Germany, used as the host mixture.

In the present application, the term threshold voltage means the optical threshold and is indicated for a relative contrast of 10% (V ₁₀ ). The mid-gray voltage and the saturation voltage are also determined optically and specified for a relative contrast of 50% and 90%, respectively. The capacitive threshold voltage (V ₀ ), also called the Freedericksz threshold, is given, so this is stated explicitly.

The specified ranges of values conclude the limits.

The concentrations are in mass% given and refer to the complete mix. temperatures are in degrees Celsius and temperature differences in degrees of difference Celsius specified. All physical properties were determined as in "Merck Liquid Crystals, Physical Properties of Liquid Crystals", As of Nov. 1997, Merck KGaA, Germany and are for one temperature of 20 ° C specified. Optical anisotropy (Δn), also called birefringence, becomes at a wavelength determined from 589.3 nm. The dielectric anisotropy (Δε) is at determined at a frequency of 1 kHz.

In a list of alternative options if only the plural is specified, this also means the singular.

• – „enthalten", dass die Konzentration des jeweiligen genannten Materials, also der Komponente oder der Verbindung, in der Bezugseinheit, also dem Medium bzw. der Komponente, bevorzugt 10% oder mehr, besonders bevorzugt 20 % oder mehr und ganz besonders bevorzugt 30% oder mehr beträgt,
• – „überwiegend bestehen aus", dass die Konzentration des genannten Materials in der Bezugseinheit bevorzugt 50% oder mehr, besonders bevorzugt 60 % oder mehr und ganz besonders bevorzugt 70% oder mehr beträgt und
• – „nahezu vollständig bestehen aus", dass die Konzentration des genannten Materials in der Bezugseinheit bevorzugt 80% oder mehr, besonders bevorzugt 90 % oder mehr und ganz besonders bevorzugt 95% oder mehr beträgt.

In connection with information on the composition of the media, or their components, means

• - "contain" that the concentration of the respective material mentioned, ie the component or the compound, in the reference unit, ie the medium or the component, preferably 10% or more, particularly preferably 20% or more and very particularly preferably 30% or more,
• "Predominantly consist of" that the concentration of the material mentioned in the reference unit is preferably 50% or more, particularly preferably 60% or more and very particularly preferably 70% or more and
• "Almost completely consist of" that the concentration of the material mentioned in the reference unit is preferably 80% or more, particularly preferably 90% or more and very particularly preferably 95% or more.

The dielectric properties, electro-optical properties (eg the threshold voltages) and the switching times were determined in test cells manufactured by Merck KGaA, Darmstadt, Germany. The test cells for determining Δε had a layer thickness of 22 μm and a circular electrode made of indium tin oxide (ITO) with an area of 1.13 cm ² and a protective ring. For homeotropic orientation to determine ε || cells with a homeotropically oriented polyimide orientation layer were used. Alternatively, lecithin (Merck KGaA) can be used as an orientation aid. The cells for determining ε ε had orientation _layers made of the polyimide AL-1054 from Japan Synthetic Rubber, Japan. The capacitances were generally measured with a Solatron 1260 frequency analyzer with a square wave with an effective voltage of 0.3 V _rms . The electro-optical examinations were carried out with white light. The characteristic tensions were determined under vertical observation.

Table A:

In the present application, particularly in the examples described below, the structures of the chemical compounds are indicated by means of abbreviations. The meaning of the respective abbreviations is summarized in Tables A and B below. All groups C _n H _{2n + 1} and C _m H _{2m + 1} are straight-chain alkyl groups with n or m C atoms. Table B is self-explanatory, since it gives the full abbreviation for a formula of homologous compounds. Table A shows only the abbreviations for the core structures of the connection types. The abbreviations for the respective individual compounds are composed of the respectively applicable abbreviations for the core of the compound and the abbreviation for the groups R ¹ , R ² , L ¹ and L ² attached by means of a hyphen according to the following table.

Table A:

Table B:

• – vier oder mehr, bevorzugt sechs oder mehr, Verbindungen ausgewählt aus der Gruppe der Verbindungen der Tabellen A und B und/oder
• – fünf oder mehr Verbindungen ausgewählt aus der Gruppe der Verbindungen der Tabelle B und/oder
• – zwei oder mehr Verbindungen ausgewählt aus der Gruppe der Verbindungen der Tabelle A.

The mesogenic media according to the present application preferably contain

• - Four or more, preferably six or more, compounds selected from the group of compounds of Tables A and B and / or
• - Five or more compounds selected from the group of compounds in Table B and / or
• Two or more compounds selected from the group of compounds in Table A.

Examples

The examples described below illustrate the present invention without it in any Kind of restrict. Furthermore, they show the skilled person which properties and in particular which combinations of properties achieved with the present ending can be.

Comparative example

The mesogenic with the following composition was prepared. Link / shortcut Concentration / mass% UZU-3A-N 12, 0 UZU-5A-N 12, 0 GZU-3A-N 12.0 GZU-5A-N 11, 0 GZU-3O-N 10.0 UVZG-3-N 10, 0 CUZU-2-N 10.0 CUZU-3-N 10.0 CUZU-4-N 10.0 HP 5N.F 3.0 Σ 100.0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 23.7 n _e (20 ° C, 589.3 nm): 1.6187 Δn (20 ° C, 589.3 nm): 0.0925

This liquid crystal mixture patent application DE 102 172 73.0 was filled into a test cell and examined for its electro-optical properties at a temperature of 24 ° C.

The test cell used showed how shown in application 1, electrodes on only one of the two Substrates. An electro-optical test cell with a light switching element containing the liquid crystal mixture was produced. The substrates were made of glass. There were substrates used without orientation layer. The electrode structure existed from interdigitated comb-shaped Electrodes. The distance between the electrodes was 20 μm and The width of the electrodes from each other was 10 μm. The layer thickness of the electrodes was 60 nm. The electrodes were all in one Level. The layer thickness of the control medium was 6.8 μm.

A first polarizer was used in front and a second polarizer behind the cell as the analyzer. The absorption axes of the two polarizers formed an angle of 90 ° to one another. The angle between the axis of maximum absorption of the polarizers and the component of the electric field in the plane of the display was 45 ° in each case. The voltage transmission characteristic was determined with an electro-optical measuring station DMS 703 from Autronic-Melchers, Karlsruhe, Germany. The operating temperature was 24.0 ° C. When observed vertically, a curve was obtained which is typical for a cell with electrically controlled birefringence (e.g. ECB). The value of the threshold voltage (V ₁₀ ) was 40.5 V, the value of the medium gray voltage (V ₅₀ ) was 56 V and the value of the saturation voltage (V ₉₀ ) was 65 V. The maximum contrast was reached at 73 V. At voltages of 80 V or 90 V, the relative contrast dropped again to 90% or 50%. These results are also summarized in the following table.

Table 1: Characteristic tensions

example 1

The mixture of the comparative example was placed in a test cell according to the teaching filled the present application and their electro-optical properties also at one temperature of 24 ° C certainly. The test cell had the same structure as that in the comparative example used, but here was the distance between the electrodes 10 μm and the width of the electrodes 5 μm.

The cell thus obtained reached at a voltage of 26.5 V 10 relative contrast, at 38 V 50 % relative contrast and at 46 V 90% relative contrast. The maximum Contrast was achieved at 51 V. At voltages of 60 V, the relative contrast back to 90%. These results are for comparison with those of the comparative example in Table 1.

As you can see from this table can, are all characteristic voltages of the liquid crystal switching element Example 1 significantly lower than that of the comparative example. The degradation is on average for the first four values about 31%.

Example 2

The mixture used in the comparative example and in example 1 was filled into a test cell according to another embodiment of the teaching of the present application and its electro-optical properties were also determined at a temperature of 24 ° C. The test cell had a structure according to 7 , As with the cell used in Example 1, the distance between the electrodes was 10 μm and the width of the electrodes was 5 μm. Here, however, the electrodes were on pedestals. These had a layer thickness of 1.5 μm and consisted of the material of the substrate.

The cell thus obtained reached at a voltage of 25 V 10% relative contrast, at 33.5 V 50% relative contrast and at 41 V 90 relative contrast. The maximum contrast was achieved at 45 V. These results are also included in Table 1.

As you can see here, everyone is characteristic voltages of the liquid crystal switching element of the Example 2 again significantly lower than that of the example 1. The lowering of the corresponding values compared to those of the comparative example here is on average around 38%.

Example 3

The in the comparative example and in The mixture used in previous Examples 1 and 2 was placed in a test cell according to another another embodiment filled according to the teaching of the present application and its electro-optical Properties also determined at a temperature of 24 C.

The test cell had pairs of electrodes on the inside of both substrates as in 8th shown. The electrodes directly opposite one another on the two substrates were connected to one another in an electrically conductive manner, or the same potential was applied to these electrodes. As in Examples 1 and 2, the distance between the electrodes was 10 μm and the width of the electrodes was 5 μm.

The cell thus obtained reached at a voltage of 21 V 10 relative contrast, at 29 V 50% relative contrast and at 35 V 90 relative contrast. The maximum Contrast was reached at 37.5 V. At voltages of 41 V or 47 V, the relative contrast dropped back to 90% and 50%, respectively. This Results are also shown in Table 1.

As you can see from this table can, are all characteristic voltages of the liquid crystal switching element of Example 2 have been lowered again. The humiliation of the corresponding Values compared to those of the comparative example are in here Average at about 48%, so the values are only about half that as big as that of the comparative example.

Example 4

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% ME2N.F 3.0 ME3N.F 3.0 ME4N.F 8.0 ME5N.F 8.0 UM 3-N 4.0 PTG-3-N 8.0 PTG-5-N 8.0 PTU-4O-N 8.0 PU 3-AN 8.0 PU-5-AN 8.0 PGU-2-F 10.0 PGU-3-F 10.0 PGU-5-F 10.0 HP 3N.F 4.0 Σ 100.0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 23.8 n _e (20 ° C, 589.3 nm): 1.6971 Δn (20 ° C, 589.3 nm): .1456 ε || (20 ° C, 1 kHz): 47.4 Δε (20 ° C, 1 kHz): 27.3

As in example 3, an electro-optical display is implemented and its characteristic is measured. The temperature is 24.0 ° C. The value of the threshold voltage (V ₁₀ ) is 22 V, the value of the medium gray voltage (V ₅₀ ) is 35.5 V and the value of the saturation voltage (V ₉₀ ) is 44.5 V.

Example 5

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% UM 3-N 10.0 PYP 3N.FF 15.0 HP 3N.F 10.0 CUZU-2-N 10.0 CUZU-3-N 10.0 UVZG-3-N 10.0 GZU-4O-N 10.0 GZU-4-N 1.0 GZU-3A-N 12.0 UZU-3A-N 12.0 Σ 100.0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 24.8 ne (21 ° C, 589.3 nm): 1.6372 Δn (21 ° C, 589.3 nm): 0.1122

As in example 3, an electro-optical display is implemented and its characteristic is measured. The temperature is 26.5 ° C. The characteristic curve begins at a low voltage with a relative intensity of 0% and increases with increasing voltage. The value of the threshold voltage (V ₁₀ ) is 18 V, the value of the medium gray voltage (V _{5 0} ) is 28 V and the value of the saturation voltage (V _{9 0} ) is 34 V. At a voltage of 37 V the maximum of the intensity reached.

Example 6

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% U M-3-N 10.0 GZU-3A-N 10.0 UVZG-3-N 10.0 PWZU-3-N 7, 0 PU 3-AN 16.0 PU-5-AN 16.0 PTG-3-N 15.0 PTU-4O-N 15.0 HP 3N.F 1.0 Σ 100.0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 22.9 ne (19 ° C, 589.3 nm): 1.7298 Δn (19 ° C, 589.3 nm): .1765

As in Example 3, an electro-optical Realized the display and measured its characteristic. The temperature at which the measurements were made were amounts 23.1 ° C.

The value of the threshold voltage (V ₁₀ ) is 36.5 V, the value of the mid-gray voltage (V ₅₀ ) is 28 V and the value of the saturation voltage (V _{9 0} ) is 31.5 V. The maximum of the relative contrast is 34 V.

Example 7

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% CGU-2-F 11.0 CGU-3-F 11.0 CGU-5-F 10.0 BCH 3F.FF 18.0 BCH 5F.FF 14.0 PGU-2-F 11.0 PGU-3-F 11.0 PGU-5-F 11.0 BCH-32 3.0 Σ 100.0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 23.5 n _e (20 ° C, 589.3 nm): 1.6138 Δn (20 ° C, 589.3 nm): 0.0854 ε || (20 ° C, 1 kHz): 16.5 Δε (20 ° C, 1 kHz): 9.1

Example 8

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% ME2N.F 10.0 UM 3-N 8.5 PTG-5-N 15.0 PTG-3-N 15.0 PU 3-AN 15.0 PU-5-AN 15.0 PTU-4O-N 15.0 HP 3N.F 6.5 Σ 100.0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 29.6 n _e (20 ° C, 589.3 nm): 1.7549 Δn (20 ° C, 589.3 nm): .2092 ε || (20 ° C, 1 kHz): 59.2 Δε (20 ° C, 1 kHz): 42.9

Example 9

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% UM 3-N 8.0 GZU-3A-N 8.0 UVZG-3-N 8.0 PWZU-3-N 10.0 PYP 40N.FF 6.0 PU 3-AN 15.0 PU-5-AN 15.0 PTG-3-N 15.0 PTU-4O-N 15.0 Σ 100.0

Example 10

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% PTG-3-N 15.0 PTG-5-N 15.0 PTU-4O-N 15.0 PU-5-AN 9.0 PGU-5-F 14.0 HP 3N.F 7.0 HP 5N.F 8.0 DU-2-N 15.0 PCH 3N.FF 2.0 Σ 100.0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 24.2 n _e (20 ° C, 589.3 nm): 1.6857 Δn (20 ° C, 589.3 nm): 0.1405 ε || (20 ° C, 1 kHz): 45.8 Δε (20 ° C, 1 kHz): 27.8

Example 11

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% CCP 2F.FF 10.0 CCP 3F.FF 10.0 CCP 5F.FF 10.0 ME2N.F 10.0 ME3N.F 10.0 ME4N.F 7.0 ME5N.F 15.0 DU-2-N 6.0 PCH 5N.FF 2.0 UM 3-N 10.0 HP 3N.F 10.0 Σ 100.0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 30.1 n _e (20 ° C, 589.3 nm): 1.6095 Δn (20 ° C, 589.3 nm): 0.1035 ε || (20 ° C, 1 kHz): 62.6 Δε (20 ° C, 1 kHz): 45.9

Example 12

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% UM 3-N 6.0 GZU-3A-N 10.0 UVZG-3-N 12.0 PWZU-3-N 10.0 PU 3-AN 15.0 PU-5-AN 15.0 PTG-3-N 15.0 PTU-4O-N 15.0 HP 3N.F 2.0 Σ 100.0

This mixture has the following properties.
Δε (20 ° C, 1 kHz)> 0

Example 13

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% CGU-2-F 11.0 CGU-3-F 11.0 CGU-5-F 10.0 BCH 3F.FF 16.0 BCH 5F.FF 14.0 PGU-2-F 10.0 PGU-3-F 10.0 PGU-5-F 9.0 PCH-7F 9.0 Σ 100.0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 11.5 Δε (20 ° C, 1 kHz) > 0

Example 14

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% CGU-2-F 12.0 CGU-3-F 12.0 CGU-5-F 11.0 BCH 3F.FF 18.0 BCH 5F.FF 14.0 PGU-2-F 11.0 PGU-3-F 11.0 PGU-5-F 11.0 Σ 100.0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 15.5 Δε (20 ° C, 1 kHz) > 0

Example 15

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% ME2N.F 3.0 ME3N.F 3.0 ME4N.F 5.0 ME5N.F 3.0 UM 3-N 4.0 PTG-3-N 8.0 PTG-5-N 8.0 PTU-4O-N 7.0 PU 3-AN 8.0 PU-5-AN 8.0 PGU-2-F 10.0 PGU-3-F 10.0 PGU-5-F 10.0 HP 3N.F 4.0 HP 4N.F 5.0 HP 5N.F 4.0 Σ 100.0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 42.3 Δε (20 ° C, 1 kHz) > 0

Example 16

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% ME2N.F 3.0 ME3N.F 3.0 ME4N.F 8.0 ME5N.F 9.0 UM 3-N 4.0 PTG-3-N 9.0 PTG-5-N 8.0 PTU-4O-N 8.0 PU 3-AN 9.0 PU-5-AN 9.0 PGU-2-F 10.0 PGU-3-F 10.0 PGU-5-F 10.0 Σ 100.0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 16.0 Δε (20 ° C, 1 kHz) > 0

Example 17

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% YY-2-O2 8.0 W-3-O2 8.0 W-4O-O4 10.0 YY V1O-O1V 8.0 PY-3-O2 15.0 PY-1-O2 11.0 CYY-3-O2 10.0 CYY-5-O2 10.0 PTP-302FF 10.0 PTP-502FF 10.0 Σ 100.0

This mixture has the following properties.
Δε (20 ° C, 1 kHz) <0

Example 18

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% W-2 O2 8.0 YY-3-O2 8.0 YY-3O-O2 6.0 W-4O-O4 6.0 W-V1O-O1V 6.0 PY-3-O2 9.0 PY-1-O2 12.0 CW-3-O2 9.0 CYY-5-O2 9.0 PTP-302FF 10.0 PTP-502FF 10.0 CPY-3-O2 5.0 CCYY-2-O2 2.0 Σ 100.0

This mixture has the following properties.
Δε (20 ° C, 1 kHz) <0

Example 19

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% PYP-5F 25.0 PCH 32 16.5 PCH-301 15.0 PCH-302 11.3 BCH-32 14.3 BCH-52 10.5 CBC 33 3.7 CBC 53 3.7 Σ 100.0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 41.0 n _e (20 ° C, 589.3 nm): 1.6157 Δn (20 ° C, 589.3 nm): .1066 ε || (20 ° C, 1 kHz): 5.7 Δε (20 ° C, 1 kHz): 2.4

Example 20

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% PCH-5F 14.6 PCH-6F 12.9 PCH-7F 12.5 PTP-20F 15.2 PTP-40F 19.1 PTP-60F 25.7 Σ 100.0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 27.0 n _e (20 ° C, 589.3 nm): 1.6470 Δn (20 ° C, 589.3 nm): .1350 ε || (20 ° C, 1 kHz): 7.4 Δε (20 ° C, 1 kHz): 3.6 k ₁ (20 ° C) / pN: 5.7 k ₂ (20 ° C) / pN: 3.1 k ₃ (20 ° C) / pN: 6.3

Example 21

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% CCP 2F.FF 4.0 CCP 20CF3 4.0 CCP 30CF3 5.0 CCP 40CF3 2.0 PCH-3 6.0 K9 4.0 BCH 3F.FF 12.0 CGU-2-F 10.0 CGU-3-F 6.0 CCZU-2-F 5.0 CCZU-3-F 16.0 CCZU-5-F 5.0 CC-5-V 2.0 CCP-V-1 10.0 CC-3-V1 9.0 Σ 100.0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 30.0 ne (20 ° C, 589.3 nm): 1.5856 Δn (20 ° C, 589.3 nm): .1007 ε || (20 ° C, 1 kHz): 14.5 Δε (20 ° C, 1 kHz): 10.6

Example 22

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% PCH-5 19.0 PCH-302 31.0 PCH-304 31.0 K15 19.0 Σ 100.0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 33.0 n _e (20 ° C, 589.3 nm): 1.6010 Δn (20 ° C, 589.3 nm): 0.1100 ε || (20 ° C, 1 kHz): 9.5 Δε (20 ° C, 1 kHz): 4.9

Example 23

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% PCH-302FF 26.0 PCH-502FF 26.0 CCP-V-1 15.0 CC-5-V 19.0 CCH-35 8.0 BCH-32 6.0 Σ 100.0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 50.0 Δε (20 ° C, 1 kHz) <0

 Example 24

The liquid crystal mixture having the following composition was prepared. Link / shortcut Concentration / mass% PCH-302FF 26.0 PCH-502FF 26.0 CCP-V-1 13.0 CC-5-V 16, 0 CCH-35 5.0 BCH-32 9.0 CCP 21FF 3.0 PCH-301 2.0 Σ 100, 0

This mixture has the following properties. Clear point (T (N, I)) / ° C: 50.0 n _e (20 ° C, 589.3 nm): 1.5640 Δn (20 ° C, 589.3 nm): .0821 ε || (20 ° C, 1 kHz): 3.9 Δε (20 ° C, 1 kHz): -2.9 γ ₁ (20 ° C) / mPas: 72

The mixtures of Examples 4 to 24 are in test cells according to the teaching filled, as described in Examples 1 to 3. The resulting light controls have similar good properties like those described in these three examples Light controls.

description of the pictures

1 : The figure shows schematically in cross section the structure of a switching element or part of a switching element according to the unpublished patent application DE 102 172 73.0 , Between the inner surfaces of the substrates ( 1 ) and ( 1' ) is the control medium ( 2 ). On the inner surface of one substrate ( 1 ) are the two electrodes ( 3 ) and ( 4 ) of the electrode structure, which can be applied with different potentials. Vop denotes the voltage, charge or current source. The lines emanating from Vop symbolize the electrical leads to the electrodes.

2 to 6 : The figures show a schematic cross section of the structure for five different embodiments of switching elements according to the invention with raised electrodes.

In the 2 the electrodes are similar to the one in 1 shown embodiment. The electrodes ( 3 ) and ( 4 ) have a rectangular or almost rectangular cross section. However, the electrodes have a thickness which is different from the layer thickness [d (2)] of the control layer ( 2 ), or compared to the characteristic layer thickness, should not be neglected, for example typically in the range from 0.3 μm to 5 μm.

In the 3 are the electrodes ( 3 ) and ( 4 ) similar to the one in 2 shown embodiment. However, these electrodes extend over the entire thickness [d ( 2 )] the control layer ( 2 ).

In the 4 are the electrodes ( 3 ) and ( 4 ) again similar to the one in 2 shown embodiment. However, the layer thickness of the electrodes ( 3 ) and ( 4 ) not constant, but depending on the location. The electrodes have a triangular cross section.

In the 5 are the electrodes ( 3 ) and ( 4 ) similar to the one in 4 shown embodiment with the location-dependent layer thickness. However, these electrodes each consist of two superimposed layers ( 3 ) and ( 3 ' ) such as ( 4 ) and ( 4 ' ), of which the upper ( 3 ' ) respectively. ( 4 ' ) covers a smaller area of the switching element than the corresponding lower layer ( 3 ) respectively. ( 4 ' ).

In the 6 are the electrodes ( 3 ) and ( 4 ) again similar to the one in 2 shown embodiment. However, the electrodes ( 3 ) and ( 4 ) here a circular cross section and are designed as a waveguide.

7 : The figure shows schematically in cross section the structure for a further preferred embodiment of switching elements according to the invention. Here the electrodes are designed similar to the one in 1 shown embodiment. However, the electrodes are not located directly on the surface of the substrate, but rather on a solid insulating layer ( 5 ) respectively. ( 6 ) of a certain thickness, for example typically in the range from 1 μm to 2 μm.

8th : The figure shows a schematic cross section of the structure for a further preferred embodiment of switching elements according to the invention with an electrode structure in which the electrodes consist of two layers, which are each on one of the substrates. Here the electrodes are designed in such a way that they 3 ) on the first substrate ( 1 ) with a first potential, a second electrode ( 3 ' ) on the second substrate ( 1' ) there that can be applied with the same potential. There is also the electrode ( 4 ) on the first substrate, to which the second potential can be applied, a second electrode ( 4 ' ) on the second substrate, which can also be acted upon by the second potential. The pairs of electrodes ( 3 ) and ( 3 ' ) such as ( 4 ) and ( 4 ' ) opposite each other.

9 to 13 : The figures schematically show in cross section the structure of various embodiments of switching elements according to the invention in accordance with a further preferred embodiment of the present extension.

9 : shows an embodiment which is a combination of the in the 7 and 8th illustrated embodiments. In contrast to in 7 shown training form are not only on the substrate with the surface ( 1 ) raised electrodes (( 3 ) and ( 4 ) on solid insulating layers ( 5 ) and ( 6 ) educated. Rather, as in the 8th illustrated embodiment also on the surface of the opposite substrate ( 1' ) Electrodes ( 3 ' ) and ( 4 ' ) educated. Like the corresponding electrodes on the first substrate, these electrodes are protected by solid insulating layers ( 5 ' ) and ( 6 ' ) from the surface ( 1' ) lifted.

In the 10 the electrodes are similar to the one in 7 shown embodiment. However, the electrodes are as shown in FIG 8th shown embodiment, each of two layers ( 3 ) and ( 3 ' ), respectively. ( 4 ) and ( 4 ' ), each with the same potential in pairs can. In contrast to that in 8th embodiment shown, the two pairs of conductive layers of the electrode structure ( 3 ) and ( 3 ' ), respectively. ( 4 ) and ( 4 ' ), however, are not affected by the dielectric control layer ( 2 ) separated from each other, but each time by a solid insulating layer ( 5 ) respectively. ( 6 ).

In the 11 the electrodes are similar to the one in 10 shown embodiment. However here, as with the in 7 shown embodiment, in each case the first layers of the electrode structures ( 3 ) respectively. ( 4 ) through a solid insulating layer ( 5 ) or (6) separated (lifted) from the substrate. The two layers of the electrode structure that can be applied with the same potential ( 3 ) and ( 3 ' ), respectively. ( 4 ) and ( 4 ' ), as in the in 10 described embodiment, in each case by a solid insulating layer, here ( 5 ' ) respectively. ( 6 ' ) called, separated from each other.

In the 12 the electrodes of the electrode structure consist of four conductive layers ( 3 ) to ( 3 ''' ) respectively. ( 4 ) to ( 4 ''' ). Two of these four layers are located on the same substrate. Layers ( 3 ) and ( 3 ' ) such as ( 4 ) and ( 4 ' ) are on the substrate with the surface ( 1 ) and ( 3 '' ) and ( 3 ''' ) such as ( 4 '' ) and ( 4 ''' ) are on the substrate with the surface ( 1' ). Of these layers, the respective substrate ( 1 ) respectively. ( 1' ) adjacent layer ( 3 ) and ( 4 ) respectively. ( 3 '' ) and ( 4 '' ) through a solid insulating layer ( 5 ) and ( 6 ) respectively. ( 5 ' ) and ( 6 ' ) Cut. The two conductive layers that are on the same substrate [( 3 ) and ( 3 ' )] and [( 4 ) and ( 4 ' )] such as [( 3 '' ) and ( 3 ''' )] and [( 4 '' ) and ( 4 ''' )] are also due to solid insulating layers ( 5 ' ) and ( 6 ' ) such as ( 5 ''' ) and ( 6 ''' ) separated from each other.

In the 13 consist of the electrodes of the electrode structure, as in the one in the illustration 12 shown embodiment, each of four conductive layers ( 2 ) to ( 2 ''' ) respectively. ( 3 ) to ( 3 ''' ). Here, however, the alternating sequence of conductive layers and insulating layers extends over the entire layer thickness of the control layer. As a result, the inner pairs of conductive layers ( 2 ' ) and ( 2 ''' ) such as ( 3 ' ) and ( 3 ''' ) also through solid insulating layers ( 5 '''' ) respectively. ( 6 '''' ) separated from each other.

1 :

Surface of the first substrate,

1 ':

Surface of the 2. substrate,

2 :

Control layer,

 3 to 3''':

First to fourth conductive Layer of the electrode structure to which the 1st potential is applied can

4 to 4''':

First to fourth conductive Layer of the electrode structure to which the 2nd potential is applied can

5 until 5'''':

First to fifth solid, insulating layer of the electrode structure, the conductive layers the electrode structure to which the 1st potential is applied can, separates,

6 until 6"":

First to fifth solid, insulating layer of the electrode structure, the conductive layers the electrode structure to which the 2nd potential is applied can, separates,

Vop :

voltage, Charge or current source

Illustrate the lines from Vop which are conductive Layers of the electrode structure are exposed to the same potential become.

Claims (14)

Electro-optical light control element comprising - a substrate or several substrates, - an electrode arrangement, - at least one element or more elements for polarizing the light and - a control medium, characterized in that - the light control element is operated at a temperature at which the control medium is not activated State is in the isotropic phase and that - the electrode arrangement can generate an electric field with a significant component parallel to the surface of the mesogenic control medium and that - the electrode arrangement is designed in such a way that at least one of the following four conditions is met - that in the plane of Control layers adjacent to one another have electrically conductive layers at a distance of 20 μm or less from one another, - the conductive layer or, if several of the electrically conductive layers are present, one or more of these layers of the electrode structure or s ind raised, - the electrode structure comprises two or more layers that overlap one another, electrically conductive tend to be connected to one another and, at the same time, are separated from one another over substantial parts of their area by a dielectric layer, - the electrically conductive layer or, if more of the electrically conductive layers are present, one or more of the conductive layers of the electrode structure is or are by solid dielectric layer separated from the respective underlying substrate. Light control element according to claim 1, characterized in that the electrode arrangement is designed such that - in the the level of the control layer adjacent electrically conductive layers a distance of 20 μm or less of each other. Light control element according to at least one of claims 1 and 2, characterized in that the electrode arrangement is designed in this way is that - the conductive Layer or, if more of the electrically conductive layers are present, one or more of these layers of the electrode structure is or are sublime. Light control element according to at least one of claims 1 to 3, characterized in that the electrode arrangement is designed in this way is that - the Electrodes made of two or more electrically connected Layers exist. Light control element according to claim 4, characterized in that - the individual layers of the electrodes essentially each - about their the whole area through a dielectric, e.g. the layer or parts of the layer of the mesogenic control medium or one or more solid dielectric Layers, separated from each other, - are of equal area and - congruent one above the other lie. Light control element according to at least one of claims 1 to 5, characterized in that - at least the conductive layers the electrode arrangement over one of the substrates increased is arranged. Light control element according to at least one of claims 1 to 6, characterized in that - at least the neighboring ones the electrodes of the electrode structure horizontally through a layer a solid dielectric medium are isolated from each other. Electro-optical display containing one or more light control elements according to at least one of the claims 1 to 7, Electro-optical display according to claim 8, characterized in that the display is controlled by an active matrix. Electro-optical display system containing one or more electro-optical displays according to at least one of claims 8 and 9th Electro-optical display system according to claim 10, characterized in that that it's as a television screen, as a computer monitor, or both can be used. Use of a light control element according to at least one of the Expectations 1 to 7, for displaying information. Use of an electro-optical display after at least one of claims 8 and 9, in an electro-optical display system. Use of an electro-optical display system according to at least one of the claims 10 and 11, for displaying video signals or digital Signals.