DE4108091A1 - High holding ratio electro=optical system - contg. liq. crystal mixt. with specified component and polymeric medium made from fluorine contg. precursor giving max. liq. crystal solubility - Google Patents

Abstract

Electro-optical systems of the type in which (A) a liq. crystal (LC) mixt. and a further optically transparent polymeric medium (OTPM) are positioned between 2 electrodes, one of which is formed as an active matrix with nonlinear, image-integrated control elements and the other of which is a counter-electrode; (B) the LC mols. are in random orientation in the switched-off state; (C) one of the RIs of the LC mixt. corresponds to the RI of the OTPM and/or the ratio LC mixt. at.: OTPM wt. = 1.5 or more; and (D) incident light shows a reduced transmission in one of the two switching states; this being independent of polarisation are claimed. Specifically, (i) the LC mixt. contains one or more cpds. of formula (I); and (ii) in order to increase the solubility of the LC mixt. in the OTPM precursor, the precursor contains 0.1-95% of a component (A) which is a fluorinated-, or oligo- or per-fluorinated aliphatic monomer, oligomer and/or prepolymer, the pref. (A) contg. a structural element of formula (II). In the formulae, Z1 and Z2 = single bond, -CH2CH2-, -COO-, -OCO- or -CC-; rings A1 and A2 = trans-1,4-cyclohexylene, 1,4-phenylene, 2- or 3-fluoro-1,4-phenylene or 2,3- or 3,5-difluoro- 1,4-phenylene, with one of A1 and A2 also being pyrimidin-2,5-diyl, pyridin-2,5-diyl or trans-1,3-dioxan-2,5-diyl; X1-4 = H or F; Q = CF2, OCF2, C2F4 or OC2F4 or a single bond; Y = H, F or Cl; n = 0, 1 or 2; R = up to 12C alkyl with 1 or 2 non-neighbouring CH2 gps. opt. replaced by -O- or -CH=CH-; and Y1-5 = such that (i) up to 2 of Y1-3 = H or F; (ii) at least 1 and upto 3 of them are a single bond and/or 1-30C alkylene gps. in which 1-15 of the CH2 gps. can be replaced by -O-, -CO-, -COO-, -OCO-, -S-, -CHHal-, -C(Hal)2- or opt. substd. satd. or aromatic cyclic diyl gps., with the proviso that -O- and/or -S- are not directly connected, and (iii) up to 2 of them are 1-30C alkyl with 1-15 CH2 gps. opt. replaced as for the alkylene gps. above. USE/ADVANTAGE - Devices with thin film transistor electrodes can be provided in which the LC/OTPM network has a high holding ratio (even at high temps. and under UV radiation) combined with a favourable threshold voltage and good stability.

Description

The invention relates to an electro-optical system,

• - Which between 2 electrode layers a Liquid crystal mixture and another optical trans contains parentes polymeric medium, wherein one of the Electrode layers as active matrix with nonlinear ren, in the pixel integrated control elements is formed while the other electrode layer forms the counterelectrode,
• - Its liquid crystal molecules in the off Condition have an irregular orientation,
• - Wherein one of the refractive indices of the liquid crystal mixture substantially coincides with the refractive index of the medium n _M and / or in which the quotient of the mass of the liquid crystal mixture and the mass of the optically transparent medium is 1.5 or more, and
• - Which is independent in one of the two switching states from the polarization of the incoming light one compared to the other state reduced transmission having.

The optically transparent medium can be separated from one another Liquid crystal microdroplets contain or a schwammar tige, 3-dimensional network, in whose pores, the to a greater or lesser degree, the liquid crystal is. By the expression Liquid crystal microdroplets become small from each other characterized limited liquid crystal compartments, the however, by no means have a spherical shape must, but irregularly shaped and / or deformed could be.

Does the optically transparent medium contain liquid crystal Microdroplets, it will be referred to as microdroplets designated system; on the other hand is a spongy, 3-di In front of the network structure before, the medium through the Characterized network expression.

NCAP and PDLC films (NCAP = nematic curvilinear aligned phases, PDLC = polymer dispersed liquid crystal) Examples of microdroplet systems. Such arrangements are z. In US 44 35 047, EP 02 72 582, US 46 88 900, US 46 71 611 and Mol. Cryst. Liq. Cryst. Inc. Nonlin. Optics 157 (1988) 427. In contrast, it is at the arrangement described in EP 03 13 053 by a network or PN system (PN = polymer network), in which the optical transparent medium a spongy network structure having.  

The nonlinear used to make the active matrix near elements may have 2 or 3 ports. at the elements with 2 connections are z. B. order α-Si: H diodes (N. Szydlo et al., Proc. 3rd Int. Conf., Kobe; SID Los Angeles, 1983, p. 416), NIHα-Si: H-Di Oden (Z. Yaniv et al., Conf. Rec. 1985 International Display Research Conference, IEEE, New York, 1985, p. 76) α-Si: H- Ring Diodes (S. Togashi et al., Proceedings of the 4th International Display Research Conference, SEE, Paris, 1984, P. 141), MIM or MSI diodes (metal-insulator-metal, metal silicon nitride-indium tin oxide; D.R. Baraff et al., Digest SID International Symposium, Los Angeles, 1980, p. 200; Suzuki, H., et al., Proceedings of the 6th International Display Research Conference, Japan Display '86, 1986, P. 72) or ZnO varistors (D.E. Castleberry et al., SID 82 Digest, 1982, p. 246). For nonlinear elements with 3 Terminals are thin-film transistors (TFT, thin film transistor), of which several types are discussed which are characterized by the semiconductor material used (eg, α-Si: H, p-Si, CdSe, Te, and others Materials; s. z. B.P.H. Knoll, Displays, Heidelberg 1986, P. 216; T. Nishimura, Mat. Res. Soc. Symp. Proc. 33 (1984) 221; C. S. Bak et al., Mat. Res. Soc. Symp. Proc. 33 (1984) 215; W. G. Hawkins et al., Hat. Res. Soc. Symp. Proc. 33 (1984) 231; M. Matsuura et al., SID 1983 Symposium Digest, 1983, p. 148).  

When using non-linear elements with 3 connections is for the counter electrode usually only one connection required, while active matrix drives, which based on 2-terminal elements, usually also the counter electrode is scanned. But they are on too 2 port based active matrix gate ments have been proposed in which only one electrode is scanned (Y. Baron et al., Proceedings of the 6th International Research Conference 1986, Japan Displax '86, P. 86), and the use of TFTs continues as well Element with only 2 terminals has been discussed (C. Hilsum et al., Displays, January 1986, p. 37).

Further details about the control of liquid crystal show by an active matrix of nonlinear elements can be found z. In A.H. Firester, SID, 1987, Society for Information Display Seminar, Seminar 5: Active Matrices for Liquid Crystals, E. Kaneko, Liquid Crystal Displays, KTK Scientific Publishers, Tokyo, Japan, 1987, chapters 6 and 7 or P.H. Knoll, Displays, Heidelberg, 1986, p. 216ff.

For operating microdroplet or network systems No polarizers are needed, so these systems have a high transmission. With an active matrix on control microdroplet or network systems provided are because of these favorable transmission properties especially for projection applications, as well as in addition for displays with high information content and more Applications have been proposed.  

The liquid crystal mixtures used in the preparation of the microdroplet or Netzwerksy systems must meet various denartigsten demands. Thus, in micro-droplet systems, one of the refractive indices of the liquid crystal is chosen to more or less coincide with the refractive index of the medium n _M. In network systems, an adjustment of the refractive indices because of the usually much higher liquid crystal content of the lichtmodu lierenden layer is not essential, but can be made to increase the light throughput and the contrast pre.

The liquid crystal mixture may be dielectrically positive or dielectrically negative. The use of dielectrically positive liquid-crystal mixtures is preferred and, in this case, an adaptation of the ordinary refractive index n _o to the refractive index of the matrix n _M takes place in general. Other adaptations are described in the literature (see, for example, EP 02 72 585) or can be stated without further ado by the person skilled in the art.

By adjusting the refractive indices is achieved that incident light in the controlled state practically no refractive index difference between the aligned ones Liquid crystal molecules and the medium looks and the Arrangement appears transparent. Furthermore, the should Liquid crystal has a high clearing point, a wide nemati range, an absence of smectic phases up to  low temperatures and high stability and have by optimizing with regard to the respective application bare optical anisotropy Δn and flow viscosity η and through a high dielectric anisotropy Δε be characterized.

For the production of the matrix or the network are So far, a number of materials and procedures have been proposed been hit. So z. B. NCAP films after in US 44 35 047 described method obtained in that the encapsulating polymeric material, such as. B. polyvinyl alcohol, the liquid-crystal mixture and a carrier material, such as As water, intimately mixed in a colloid mill become. Subsequently, the carrier material z. B. by Drying away. In contrast, in the Mol. Cryst. Liq. Cryst. Inc. Honlin. Optics 157 (1988), 427 PIPS (polymerization induced phase separation) and in the process specified in EP 02 72 585 the liquid crystal mixture first with monomers or oligomers of film-forming polymer mixed before the polymerization is initiated. The in Mol. Cryst. Liq. Cryst. Inc. Nonlin. Opt. 157 (1988), 427 described microdroplet System is based on an epoxy film while it is the arrangement specified in EP 02 72 585 is an acrylate System acts.  

When controlling the microdroplet or network system with an active matrix occurs in addition to those previously listed Requirements, which of the liquid crystal mixture, the Monomers or prepolymers and the cured polymer have to be met, another significant factor rium. This is related to the fact that every pixel with respect to the respective active nonlinear element Capacitive load represents the rhythm of the drive cycle is charged. It is more crucial Importance that the at a controlled pixel voltage drops only slightly until the pixel in the recharged next drive cycle. On quantitative measure of the drop of the at a pixel applied voltage is the so-called holding ratio (HR), which is defined as the ratio of the span waste over a pixel in the uncontrolled Condition and the applied voltage; a method for Determination of HR is z. In Rieger, B. et al., Conference Proceeding of the Freiburg Conference on Liquid Crystals, Freiburg 1989 indicated. Electro-optical systems with a low or relatively low HR are not satisfactory on the contrast.

So far, there are already considerable efforts under been taken to microdroplet and network systems in the Regarding the liquid crystal mixture used and the Optimize polymer system. On the other hand, however, are found  in the literature only a few studies on electrooptics systems based on microdroplets or networks stemen based and have an active matrix control, and there have not yet been any concepts for deployment Electro-optical systems proposed with high HR. The Previously specified systems meet the requirements for favorable properties of the liquid crystal used mixture, the monomers or oligomers and the cured Polymers at the same time high HR of the overall system only insufficient.

Another problem often is that the liquid crystal mixture too low miscibility with the Monomers, oligomers and / or prepolymers of the formation comprising polymer used in the matrix or network, which significantly affects the production of PN systems and in microdroplet matrix systems, in particular the Application of PIPS technology considerably limited.

A further disadvantage is in particular that the liquid crystal mixture or individual components of the liquid crystal mixture are often characterized by too high and / or significantly temperature-dependent solubility in the cured, matrix or network-forming polymer. If z. B. the solubility or the temperature dependence of the solubility of one or some components relatively distinct from that of the other components, it can lead to a significant influence physical properties of the mixture and in particular the refractive indices n _e and n _o , causing the adjustment of n _o or n _e or other refractive indices of the liquid crystal mixture is detuned to n _M , resulting in a deterioration of the optical properties of the system. The "bleeding" described in EP 0 357 234, according to which the liquid crystal droplets under mechanical stress of the matrix film at least partially tend to dissolve on diffusion of the liquid crystal to the film surface or into the matrix, is due to a high solubility of the liquid crystal mixture in the cured Polymer favors.

There is a great need for electro-optical systems, which meet the described requirements in a high degree and in particular have a high HR and through a good miscibility of the respective liquid crystal mixture with the monomers, oligomers and / or prepolymers of the polymer used and by a low solubility the liquid crystal mixture in the cured polymer distinguished.

The invention was based on the object, such electro optical systems and mixtures for producing such To provide systems which monomers, oligomers and / or Prepolymers of the polymer used and a liquid contain crystal mixture.  

It has been found that this problem can be solved when the liquid crystal mixture has one or more compounds containing compounds of formula I.

wherein
Z¹ and Z² are independently a single bond, -CH₂CH₂-, -COO-, -OCO- or -C≡C-,

independently of one another trans-1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4- phenylene, 2,3-difluoro-1,4-phenylene or 3,5-difluoro-1,4- phenylene and one of

also pyrimidine-2,5-diyl, pyridine-2,5-diyl or trans-1,3-dioxane-2,5-diyl,
X¹, X², X³ and X⁴ are independently H or F,
Q is CF₂, OCF₂, C₂F₄, OC₂F₄ or a single bond,
YH, F or Cl,
n 0, 1 and 2 and
R is alkyl having up to 12 C atoms, in which also one or two nonadjacent CH ₂ groups may be replaced by O and / or CH = CH,
mean, and
if the precursor of the medium for increasing the solubility of the liquid-crystal mixture in the precursor contains between 0.1% and 95% of a component A consisting of one or more fluorinated, oligofluorinated or perfluorinated aliphatic monomers, oligomers and / or prepolymers.

The invention is thus an electro-optical system

• - Which between 2 electrode layers a liquid crystal mixture and another optically transparent containing polymeric medium, wherein one of the electrodes layers as an active matrix with nonlinear, in the Pixel integrated drive elements formed while the other electrode layer is the counter electrode forms,
• - Its liquid crystal molecules in the off Condition have an irregular orientation,  
• in which one of the refractive indices of the liquid-crystal mixture corresponds substantially to the refractive index of the medium n _M and / or in which the quotient of the mass of the liquid-crystal mixture and the mass of the optically transparent medium is 1.5 or more,
• - Which is independent in one of the two switching states from the polarization of the incoming light one compared to the other state reduced transmission having,
• - The liquid crystal mixture one or more verbin contains compounds of the formula I and
• - The precursor of the medium to increase the solubility the liquid crystal mixture in the precursor between Contains 0.1% and 95.0% of a component A, which consists of one or more fluorinated, oligofluorinated or perfluorinated aliphatic monomers, oligomers and / or prepolymers.

For the sake of simplicity, in the following Phe denotes 1,4-phenyl, Phe.2F 2-fluoro-1,4-phenylene, Phe.3F 3-fluoro-1,4-phenyl, Cyc trans-1,4-cyclohexylene, Pyr pyrimidine-2,5-diyl and Pyd pyridine-2,5-diyl, wherein by the two abbreviations Pyr and Pyd in each case the two possible position isomers are included. Further, with Phe. (F) a 1,4-phenylene group and the meaning of Phe.2F3F and Phe.3F6F results analogously. Phe.2F3F5F is a tri-substituted 1,4-phenylene group in the 2-, 3- and 5-position and the meaning of Phe.2F3F6F and Phe.2F3F5F6F as a quaternary fluorinated 1,4-phenylene group results accordingly. Phe. (F) _X calculates a 1,4-phenylene group which may be unfluorinated or fluorinated at the 2, 3, 5 and / or 6 position.

Electro-optical systems whose liquid-crystal mixture has a or contains a plurality of 2-ring compounds of the formula I2, are preferred:

In the compounds of the formulas I 2 , R preferably denotes alkyl or alkoxy having 1-10, but in particular having 1-8 C atoms, the straight-chain radicals being preferred. More preferred are n-alkoxyalkyl and in particular special n-alkoxymethyl and n-alkoxyethyl.

Z 2 is preferably -CH₂CH₂-, -COO- or a single bond, in particular a single bond or -CH₂CH₂- and especially a single bond Y is -F, -Cl, -OCHF₂, -OCF₃ or -CF₃ and in particular -F, -Cl, -OCF₃ or -CF₃.  

Compounds of formula 12 wherein at least one of X¹, X², X³ and X⁴ and in particular of X¹, X² and X³ are different from H. is, are particularly preferred. Most notably preference is given to compounds of the formula 12 in which X.sup.1 = X.sup.2 = H, X³ = F and Y = -F, -Cl, -OCHF₂, -OCF₃ or -CF₃ mean.

is preferably Cyc, Phe · (F), Phe · 3F5F, Phe · 2F3F, Pyr, Pyd or Dio and in particular Cyc, Phe · (F), Phe · 3F5F, Phe · 2F3F, Pyr or Pyd.

Very particular preference is given to electro-optical systems whose Liquid crystal mixture one or more 2-nuclear compound selected from the following smaller group of Compounds of the formulas I2-1-I2-115, comprising:

R-Cyc-Phe-F | I2-1 R-Cyc-Phe · 3F-F I2-2 R-Cyc-Phe · 3F5F-F I2-3 R-Cyc-Phe-Cl I2-4 R-Cyc-Phe · 3F-Cl I2-5 R-Cyc-Phe · 3F5F-Cl I2-6 R-Cyc-Phe-OCHF₂ I2-7 R-Cyc-Phe · 3F OCHF₂ I2-8 R-Cyc-Phe · 3F5F-OCHF₂ I2-9 R-Cyc-Phe-OCF₃ I2-10 R-Cyc-Phe · 3F OCF₃ I2-11 R-Cyc-Phe · 3F5F-OCF₃ I2-12 R-Cyc-Phe-CF₃ I2-13 R-Cyc-Phe · 3F-CF₃ I2-14 R-Cyc-Phe · 3F5F-CF₃ I2-15 R-Phe-Phe-F I2-16 R-Phe-Phe · 3F-F I2-17 R-Phe-Phe · 3F5F-F I2-18 R-Phe-Phe-F · 3F5F I2-19 R-Phe-Phe-Cl I2-20 R-Phe-Phe · 3F-Cl I2-21 R-Phe-Phe-Cl · 3F5F I2-22 R-Phe-Phe-Cl · 3F5F I2-23 R-Phe-Phe-OCHF₂ I2-24 R-Phe-Phe · 3F OCHF₂ I2-25 R-Phe-Phe · 3F5F-OCHF₂ I2-26 R-Phe-Phe-3F5F · OCHF₂ I2-27 R-Phe-Phe-OCF₃ I2-28 R-Phe-Phe · 3F OCF₃ I2-29 R-Phe-Phe · 3F5F-OCF₃ I2-30 R-Phe-Phe-OCF₃ · 3F5F I2-31 R-Phe-Phe-CF₃ I2-32 R-Phe-Phe · 3F-CF₃ I2-33 R-Phe-Phe · 3F5F-CF₃ I2-34 R-Phe-Phe-CF₃ · 3F5F I2-35 R-Cyc-CH₂CH₂-Phe-F I2-36 R-Cyc-CH₂CH₂-Phe · 3F-F I2-37 R-Cyc-CH₂CH₂-Phe · 3F5F-F I2-38 R-Cyc-CH₂CH₂-Phe-Cl I2-39 R-Cyc-CH₂CH₂-Phe · 3F-Cl I2-40 R-Cyc-CH₂CH₂-Phe · 3F5F-Cl I2-41 R-Cyc-CH₂CH₂-Phe-OCHF₂ I2-42 R-Cyc-CH₂CH₂-Phe · 3F OCHF₂ I2-43 R-Cyc-CH₂CH₂-Phe · 3F5F-OCHF₂ I2-44 R-Cyc-CH₂CH₂-Phe-OCF₃ I2-45 R-Cyc-CH₂CH₂-Phe · 3F OCF₃ I2-46 R-Cyc-CH₂CH₂-Phe · 3F5F-OCF₃ I2-47 R-Cyc-CH₂CH₂-Phe-CF₃ I2-48 R-Cyc-CH₂CH₂-Phe · 3F-CF₃ I2-49 R-Cyc-CH₂CH₂-Phe · 3F5F-CF₃ I2-50 R-Cyc-COO-Phe-F I2-51 R-Cyc-COO-Phe · 3F-F I2-52 R-Cyc-COO-Phe · 3F5F-F I2-53 R-Cyc-COO-Phe-Cl I2-54 R-Cyc-COO-Phe · 3F-Cl I2-55 R-Cyc-COO-Phe · 3F5F-Cl I2-56 R-Cyc-COO-Phe-OCHF₂ I2-57 R-Cyc-COO-Phe · 3F OCHF₂ I2-58 R-Cyc-COO-Phe · 3F5F-OCHF₂ I2-59 R-Cyc-COO-Phe-OCF₃ I2-60 R-Cyc-COO-Phe · 3F OCF₃ I2-61 R-Cyc-COO-Phe · 3F5F-OCF₃ I2-62 R-Cyc-COO-Phe-CF₃ I2-63 R-Cyc-COO-Phe · 3F-CF₃ I2-64 R-Cyc-COO-Phe · 3F5F-CF₃ I2-65 R-COO-Phe-Phe-F I2-66 R-Phe-Phe-COO · 3F-F I2-67 R-Phe-Phe-COO · 3F5F-F I2-68 R-Phe · 3F5F-COO-Phe-F I2-69 R-COO-Phe-Phe-Cl I2-70 R-COO-Phe-Phe-3F-Cl I2-71 R-Phe-Phe-COO · 3F5F-Cl I2-72 R-Phe · 3F5F-COO-Phe-Cl I2-73 R-Phe-COO-Phe-OCHF₂ I2-74 R-Phe-Phe-COO · 3F OCHF₂ I2-75 R-Phe-Phe-COO · 3F5F-CHCF₂ I2-76 R-Phe · 3F5F-COO-Phe-OCHF₂ I2-77 R-Phe-COO-Phe-OCF₃ I2-78 R-Phe-Phe-COO · 3F OCF₃ I2-79 R-Phe-Phe-COO · 3F5F-OCF₃ I2-80 R-Phe · 3F5F-COO-Phe-OCF₃ I2-81 R-Phe-COO-Phe-CF₃ I2-82 R-Phe-Phe-COO · 3F-CF₃ I2-83 R-Phe-Phe-COO · 3F5F-CF₃ I2-84 R-Phe · 3F5F-COO-Phe-CF₃ I2-85 R-Pyr-Phe-F I2-86 R-Pyr-Phe · 3F-F I2-87 R-Pyr-Phe · 3F5F-F I2-88 R-Pyr-Phe-Cl I2-89 R-Pyr-Phe · 3F-Cl I2-90 R-Pyr-Phe · 3F5F-F-Cl I2-91 R-Pyr-Phe-OCHF₂ I2-92 R-Pyr-Phe · 3F OCHF₂ I2-93 R-Pyr-Phe · 3F5F F OCHF₂ I2-94 R-Pyr-Phe · 3F OCF₃ I2-96 R-Pyr-Phe · 3F5F F OCF₃ I2-97 R-Pyr-Phe-CF₃ I2-98 R-Pyr-Phe · 3F-CF₃ I2-99 R-Pyr-Phe · 3F5F F CF₃ I2-100 R-Pyd-Phe-F I2-101 R-Pyd-Phe · 3F-F I2-102 R-Pyd-Phe · 3F5F-F I2-103 R-Pyd-Phe-Cl I2-104 R-Pyd-Phe · 3F-Cl I2-105 R-Pyd-Phe · 3F5F-F-Cl I2-106 R-Pyd-Phe-OCHF₂ I2-107 R-Pyd-Phe · 3F OCHF₂ I2-108 R-Pyd-Phe · 3F5F F OCHF₂ I2-109 R-Pyd-Phe-OCF₃ I2-110 R-Pyd-Phe · 3F OCF₃ I2-111 R-Pyd-Phe · 3F5F F OCF₃ I2-112 R-Pyd-Phe-CF₃ I2-113 R-Pyd-Phe · 3F-CF₃ I2-114 R-Pyd-Phe · 3F5F F CF₃ I2-115

Further preferred are electro-optical systems whose Liquid crystal mixture one or more 3-nuclear compound of the formula I3 contains:

In the compounds of the formula I3, R is preferably n-alkyl or n-alkoxy having 1-10 C atoms, in addition also n-alkoxymethyl or n-alkoxyethyl having 1-8 C atoms and n-alkenyl with up to 7 carbon atoms.  

Very particular preference is given to compounds of the formulas I3 in which R is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy, octoxy, methoxymethyl, ethoxyme methyl, propoxymethyl, butoxymethyl, methoxyethyl, ethoxyethyl or propoxyethyl. Z ¹ and Z ² in the connec tions of the formulas I3 independently of one another preferably -CH₂CH₂-, -COO- or a single bond and in particular -CH₂CH₂- or a single bond. Particular preference is given to those compounds of the formula I3 in which at least one of Z.sup.1 or Z.sup.2 denotes a single bond. Y is -F, -Cl, -OCHF₂, -OCF₃ or -CF₃ and especially -F, -Cl, -OCHF₂ and -OCF₃. Compounds of formula I3 wherein X⁴ = H and X¹, X² and / or X³ = F are preferred.

independently of one another are Cyc, Phe · (F), Phe · 2F3F, Phe · 3F5F, Phe · 2F3F5F, Pyr, Pyd and Dio and in particular Cyc, Phe · (F), Phe · 2F3F, Phe · 3F5F, Phe · 2F3F5F, Pyr and Pyd.

Electro-optical systems whose liquid-crystal mixture has a or more compounds selected from the following smaller group of compounds of the formulas I3-1-I3-160 contains, are particularly preferred:

R-Cyc-Cyc-Phe-F | I3-1 R-Cyc-Cyc-Phe · 3F-F I3-2 R-Cyc-Cyc-Phe · 3F5F-F I3-3 R-Cyc-Cyc-Phe-Cl I3-4 R-Cyc-Cyc-Phe · 3F-Cl I3-5 R-Cyc-Cyc-Phe · 3F5F-Cl I3-6 R-Cyc-Cyc-Phe-OCHF₂ I3-7 R-Cyc-Cyc-Phe · 3F OCHF₂ I3-8 R-Cyc-Cyc-Phe · 3F5F-OCHF₂ I3-9 R-Cyc-Cyc-Phe-OCF₃ I3-10 R-Cyc-Cyc-Phe · 3F OCF₃ I3-11 R-Cyc-Cyc-Phe · 3F5F-OCF₃ I3-12 R-Cyc-Cyc-Phe-CF₃ I3-13 R-Cyc-Cyc-Phe · 3F-CF₃ I3-14 R-Cyc-Cyc-Phe · 3F5F-CF₃ I3-15 R-Cyc-Phe-Phe-F I3-16 R-Cyc-Phe-Phe · 3F-F I3-17 R-Cyc-Phe-Phe · 3F5F-F I3-18 R-Cyc-Phe-Phe-F · 3F5F I3-19 R-Cyc-Phe-Phe-Cl I3-20 R-Cyc-Phe-Phe · 3F-Cl I3-21 R-Cyc-Phe-Phe-Cl · 3F5F I3-22 R-Cyc-Phe-Phe-Cl · 3F5F I3-23 R-Cyc-Phe-Phe-OCHF₂ I3-24 R-Cyc-Phe-Phe · 3F OCHF₂ I3-25 R-Cyc-Phe-Phe · 3F5F-OCHF₂ I3-26 R-Cyc-Phe-Phe-3F5F · OCHF₂ I3-27 R-Cyc-Phe-Phe-OCF₃ I3-28 R-Cyc-Phe-Phe · 3F OCF₃ I3-29 R-Cyc-Phe-Phe · 3F5F-OCF₃ I3-30 R-Cyc-Phe-Phe-OCF₃ · 3F5F I3-31 R-Cyc-Phe-Phe-CF₃ I3-32 R-Cyc-Phe-Phe · 3F-CF₃ I3-33 R-Cyc-Phe-Phe · 3F5F-CF₃ I3-34 R-Cyc-Phe-Phe-CF₃ · 3F5F I3-35 R-Phe-Phe-Phe-F I3-36 R-Phe-Phe-Phe · 3F-F I3-37 R-Phe-Phe-Phe · 3F5F-F I3-38 R-Phe-Phe-Phe-F · 3F5F I3-39 R-Phe-Phe-Phe-Cl I3-40 R-Phe-Phe-Phe · 3F-Cl I3-41 R-Phe-Phe-Phe-Cl · 3F5F I3-42 R-Phe-Phe-Phe-Cl · 3F5F I3-43 R-Phe-Phe-Phe-OCHF₂ I3-44 R-Phe-Phe-Phe · 3F OCHF₂ I3-45 R-Phe-Phe-Phe-3F5F · OCHF₂ I3-46 R-Phe-Phe-Phe · 3F5F-OCHF₂ I3-47 R-Phe-Phe-Phe-OCF₃ I3-48 R-Phe-Phe-Phe · 3F OCF₃ I3-49 R-Phe-Phe-Phe-OCF₃ · 3F5F I3-50 R-Phe-Phe-Phe · 3F5F-OCF₃ I3-51 R-Phe-Phe-Phe-CF₃ I3-52 R-Phe-Phe-Phe · 3F-CF₃ I3-53 R-Phe-Phe-Phe-CF₃ · 3F5F I3-54 R-Phe-Phe-Phe · 3F5F-CF₃ I3-55 R-Cyc-Pyr-Phe-F I3-56 R-Cyc-Pyr-Phe · 3F-F I3-57 R-Cyc-Pyr-Phe · 3F5F-F I3-58 R-Cyc-Pyr-Phe-Cl I3-59 R-Cyc-Pyr-Phe · 3F-Cl I3-60 R-Cyc-Pyr-Phe-Cl · 3F5F I3-61 R-Cyc-Pyr-Phe-OCHF₂ I3-62 R-Cyc-Pyr-Phe · 3F OCHF₂ I3-63 R-Cyc-Pyr-Phe-OCF₃ I3-65 R-Cyc-Pyr-Phe · 3F OCF₃ I3-66 R-Cyc-Pyr-Phe · 3F5F-OCF₃ I3-67 R-Cyc-Pyr-Phe-CF₃ I3-68 R-Cyc-Pyr-Phe · 3F-CF₃ I3-69 R-Cyc-Pyr-Phe · 3F5F-CF₃ I3-70 R-Cyc-Pyd-Phe-F I3-71 R-Cyc-Pyd-Phe · 3F-F I3-72 R-Cyc-Pyd-Phe · 3F5F-F I3-73 R-Cyc-Pyd-Phe-Cl I3-74 R-Cyc-Pyd-Phe · 3F-Cl I3-75 R-Cyc-Pyd-Phe · 3F5F-Cl I3-76 R-Cyc-Pyd-Phe-OCHF₂ I3-77 R-Cyc-Pyd-Phe · 3F OCHF₂ I3-78 R-Cyc-Pyd-Phe · 3F5F-OCHF₂ I3-79 R-Cyc-Pyd-Phe-OCF₃ I3-80 R-Cyc-Pyd-Phe · 3F OCF₃ I3-81 R-Cyc-Pyd-Phe · 3F5F-OCF₃ I3-82 R-Cyc-Pyd-Phe-CF₃ I3-83 R-Cyc-Pyd-Phe · 3F-CF₃ I3-84 R-Cyc-Pyd-Phe · 3F5F-CF₃ I3-85 R-Pyr-Phe-Phe-F I3-86 R-Pyr-Phe-Phe · 3F-F I3-87 R-Pyr-Phe-Phe · 3F5F-F I3-88 R-Pyr-Phe-Phe-Cl I3-89 R-Pyr-Phe-Phe · 3F-Cl I3-90 R-Pyr-Phe-Phe-Cl · 3F5F I3-91 R-Pyr-Phe-Phe-OCHF₂ I3-92 R-Pyr-Phe-Phe · 3F OCHF₂ I3-93 R-Pyr-Phe-Phe-OCF₃ I3-95 R-Pyr-Phe-Phe · 3F OCF₃ I3-96 R-Pyr-Phe-Phe · 3F5F-OCF₃ I3-97 R-Pyr-Phe-Phe-CF₃ I3-98 R-Pyr-Phe-Phe · 3F-CF₃ I3-99 R-Pyr-Phe-Phe · 3F5F-CF₃ I3-100 R-Pyd-Phe-Phe-F I3-101 R-Pyd-Phe-Phe · 3F-F I3-102 R-Pyd-Phe-Phe · 3F5F-F I3-103 R-Pyd-Phe-Phe-Cl I3-104 R-Pyd-Phe-Phe · 3F-Cl I3-105 R-Pyd-Phe-Phe-Cl · 3F5F I3-106 R-Pyd-Phe-Phe-OCHF₂ I3-107 R-Pyd-Phe-Phe · 3F OCHF₂ I3-108 R-Pyd-Phe-Phe · 3F5F-OCHF₂ I3-109 R-Pyd-Phe-Phe-OCF₃ I3-110 R-Pyd-Phe-Phe · 3F OCF₃ I3-111 R-Pyd-Phe-Phe · 3F5F-OCF₃ I3-112 R-Pyd-Phe-Phe-CF₃ I3-113 R-Pyd-Phe-Phe · 3F-CF₃ I3-114 R-Pyd-Phe-Phe · 3F5F-CF₃ I3-115 R-Cyc-Cyc-CH₂CH₂-Phe-F I3-116 R-Cyc-Cyc-CH₂CH₂-Phe · 3F-F I3-117 R-Cyc-Cyc-CH₂CH₂-Phe · 3F5F-F I3-118 R-Cyc-Cyc-CH₂CH₂-Phe-Cl I3-119 R-Cyc-Cyc-CH₂CH₂-Phe · 3F-Cl I3-120 R-Cyc-Cyc-CH₂CH₂-Phe · 3F5F-Cl I3-121 R-Cyc-Cyc-CH₂CH₂-Phe-OCHF₂ I3-122 R-Cyc-Cyc-CH₂CH₂-Phe · 3F OCHF₂ I3-123 R-Cyc-Cyc-CH₂CH₂-Phe · 3F5F-OCHF₂ I3-124 R-Cyc-Cyc-CH₂CH₂-Phe-OCF₃ I3-125 R-Cyc-Cyc-CH₂CH₂-Phe · 3F OCF₃ I3-126 R-Cyc-Cyc-CH₂CH₂-Phe · 3F5F-OCF₃ I3-127 R-Cyc-Cyc-CH₂CH₂-Phe-CF₃ I3-128 R-Cyc-Cyc-CH₂CH₂-Phe · 3F5F-CF₃ I3-129 R-Cyc-Cyc-CH₂CH₂-Phe · 3F-CF₃ I3-130 R-Cyc-CH₂CH₂-Phe-Phe-F I3-131 R-Cyc-CH₂CH₂-Phe-Phe · 3F-F I3-132 R-Cyc-CH₂CH₂-Phe-Phe · 3F5F-F I3-133 R-Cyc-CH₂CH₂-Phe-Phe-Cl I3-134 R-Cyc-CH₂CH₂-Phe-Phe · 3F-Cl I3-135 R-Cyc-CH₂CH₂-Phe-Phe-Cl · 3F5F I3-136 R-Cyc-CH₂CH₂-Phe-Phe-OCHF₂ I3-137 R-Cyc-CH₂CH₂-Phe-Phe · 3F OCHF₂ I3-138 R-Cyc-CH₂CH₂-Phe-Phe · 3F5F-OCHF₂ I3-139 R-Cyc-CH₂CH₂-Phe-Phe-OCF₃ I3-140 R-Cyc-CH₂CH₂-Phe-Phe · 3F OCF₃ I3-141 R-Cyc-CH₂CH₂-Phe-Phe · 3F5F-OCF₃ I3-142 R-Cyc-CH₂CH₂-Phe-Phe-CF₃ I3-143 R-Cyc-CH₂CH₂-Phe-Phe · 3F-CF₃ I3-144 R-Cyc-CH₂CH₂-Phe-Phe · 3F5F-CF₃ I3-145 R-Cyc-Phe-COO-Phe-F I3-146 R-Cyc-Phe-Phe-COO · 3F-F I3-147 R-Cyc-Phe-Phe-COO · 3F5F-F I3-148 R-Cyc-Phe-COO-Phe-Cl I3-149 R-Cyc-Phe-Phe-COO · 3F-Cl I3-150 R-Cyc-Phe-Phe-COO · 3F5F-Cl I3-151 R-Cyc-Phe-COO-Phe-OCHF₂ I3-152 R-Cyc-Phe-Phe-COO · 3F OCHF₂ I3-153 R-Cyc-Phe-Phe-COO · 3F5F-OCHF₂ I3-154 R-Cyc-Phe-COO-Phe-OCF₃ I3-155 R-Cyc-Phe-Phe-COO · 3F OCF₃ I3-156 R-Cyc-Phe-Phe-COO · 3F5F-OCF₃ I3-157 R-Cyc-Phe-COO-Phe-CF₃ I3-158 R-Cyc-Phe-Phe-COO · 3F-CF₃ I3-159 R-Cyc-Phe-Phe-COO · 3F5F-CF₃ I3-160

Electro-optical systems whose liquid-crystal mixtures contain one or more compounds of the formulas I2 or I3 in which X ² and / or X ³ denote F, have advantageous values for the dielectric anisotropy and in many cases also favorable values for the elastic constants. Particularly advantageous values for AG are those electro-optical systems whose liquid-crystal mixture contains one or more compounds of the formulas I2-86-I2-115 and I3-56-I3-115. Electro-optical systems whose liquid-crystal mixture has at least one 2-nuclear compound of the formula I 2 and a 3-nuclear compound of the formula I 3 are frequently characterized by particularly advantageous properties. Liquid-crystal mixtures which contain one or more compounds of the formula I 3 which are laterally fluorinated at least twice are distinguished in many cases by a particularly favorable miscibility with the monomers, oligomers and / or prepolymers described below and are preferred.

Further preferred are electro-optical systems whose Liquid crystal mixture one or more 4-core Compounds of the formula I4 contains:

In the compounds of the formulas Ib1-Ib8, R is preferably example, n-alkyl or n-alkoxy having 1-10 C atoms, in addition also n-alkoxymethyl or n-alkoxyethyl having 1-8 C atoms.  

Very particular preference is given to compounds of the formulas I 4 in which R is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy or octoxy.

In the compounds of formula I4 are preferably not more than 2 and in particular only one of the bridges Z² and Z² different from a single bond.

are preferably independently of one another Cyc, Phe · 2F, Phe · 3F, Phe, Pyr or Pyd. Compounds of the formula I4, in which at least one of

Phe · 2F or Phe · 3F are preferred. The mass fraction of the compounds of the formulas I4 on the liquid-crystal mixture of the electrooptical systems according to the invention is preferably not too high and is in particular less than 20%, the use of laterally fluorinated compounds of the formula I 4 being often preferred.

Electro-optical systems whose liquid-crystal mixture has a or more compounds selected from the following smaller group of compounds of the formulas I4-1-I4-15 contains, are particularly preferred:

R-Cyc-Phe · (F) -Phe · (F) -Phe · (F) _x -F | I4-1 R-Cyc-Phe · (F) -Phe · (F) -Phe · (F) _x -Cl I4-2 R-Cyc-Phe · (F) -Phe · (F) -Phe · (F) _x -OCHF₂ I4-3 R-Cyc-Phe · (F) -Phe · (F) -Phe · (F) _x -OCF₃ I4-4 R-Cyc-Phe · (F) -Phe · (F) -Phe · (F) _x -CF₃ I4-5 R-Cyc-Cyc-Phe · (F) -Phe · (F) _x -F I4-6 R-Cyc-Cyc-Phe · (F) -Phe · (F) _x -Cl I4-7 R-Cyc-Cyc-Phe · (F) -Phe · (F) _x -OCHF₂ I4-8 R-Cyc-Cyc-Phe · (F) -Phe · (F) _x -OCF₃ I4-9 R-Cyc-Cyc-Phe · (F) -Phe · (F) _x -CF₃ I4-10 R-Cyc-Cyc-Cyc-Phe · (F) _x -F I4-11 R-Cyc-Cyc-Cyc-Phe · (F) _x -Cl I4-12 R-Cyc-Cyc-Cyc-Phe · (F) _x -OCHF₂ I4-13 R-Cyc-Cyc-Cyc-Phe · (F) _x -OCF₃ I4-14 R-Cyc-Cyc-Cyc-Phe · (F) _x -CF₃ I4-15

It has been found that electro-optical systems,

• - whose liquid crystal mixture one or more verbin of the formula I and in particular one or more Compounds of the formulas I2-1 - I2-115, I3-1 - I3-160 and I4-1 - I4-15 contains, and
• - Their medium by polymerization of a precursor which is between 0.1% and 95.0% of a Component A contains, which consists of one or more fluorinated, oligofluorinated or perfluorinated aliphatic monomers, oligomers and / or Prepolymer exists, particularly favorable properties respectively.

These systems are characterized by advantageous values for the Threshold voltage, high UV and temperature stability, through a favorable working temperature range, through favorable values for the temperature dependence of the elektroop table parameters, with a high contrast and in particular This is characterized by a high HR.

The liquid crystal mixture is characterized by a good Miscibility with the precursor often already in space temperature or slightly elevated temperatures off and only in Few cases is enough to achieve a sufficient mix availability of precursor and liquid-crystal mixture Heating to temperatures of more than 60 ° C required. It has been found that the monomers, oligomers and / or Prepolymers of component A of the precursor to increase the solubility of the liquid crystal mixture in the precursor preferably have a structural element of the formula II

wherein
up to 2 of Y¹, Y² and Y³ are independently H or F,
at least one and up to 3 of the radicals Y ¹ -Y ³ independently of one another an alkylene group having 1-30 C atoms, in which also 1-15 CH ₂ groups independently of one another by -O-, -CO-, -COO-, - OCO-, -S-, -CHHalogen-, -C (halogen) ₂ - substituted or unsubstituted or substituted or unsubstituted saturated or aromatic cyclic diyl groups may be replaced, wherein 0 and / or S are not directly linked together, and / or a Single bond, and
up to 2 of the radicals Y ¹ -Y ^3, an alkyl group having 1-30 C atoms, wherein also 1-15 CH ₂ groups independently of one another by -O-, -CO-, -COO-, -OCO-, -S -, -CHHalogen-, -C (halogen) ₂ - or substituted or unsubstituted saturated or aromatic cyclic diyl groups may be replaced, wherein O and / or S are not directly linked together,
mean.

The group II may be a terminal or a non-terminal group of the respective monomer, oligomer and / or prepolymer. In this case, a terminal group II is defined such that 2 of the radicals Y ¹ -Y ^{3 are} not capable of polymerization, ie no polymerizable group, while one of the radicals Y ¹ -Y ^{3 represents} an alkylene group or a single bond which represents the group II connects with a polymerizable radical. In contrast, in nonterminal groups II, at least 2 of the radicals Y ¹ -Y ³ denote an alkylene group and / or a single bond which connects the group II with polymerizable radicals. Since the alkylene groups defined above and / or one or more single bonds link the structural element II to the polymerizable radical or radicals P, the alkylene groups or the single bond should also be referred to below as the intermediate group Z.

The polymerizable radicals have one or more polymerizable groups on the number of characterized by the given linking sites are. So z. B. the preferred substituted or unsubstituted vinyl groups

and the most preferred substituted or unsubstituted acryloyloxy groups

and the also preferred substituted or unsubstituted tuierten epoxide groups

and the most preferred substituted or unsubstituted ones epichlorohydrin

2 nodes on while the groups

are preferred groups with a point of attachment. The above polymerizable groups may be substituted or unsubstituted, being subtitles the radicals given in formula II are preferred. The olefinically unsaturated polymerizable groups may be both non-cyclic and cyclic, wherein the cyclic groups are preferably cyclopentene, cyclo pentadiene, cyclohexene, cyclolohexadiene and cyclic Acrylic groups are derived.

Monomers, oligomers and / or prepolymers of the components A and B usually have at least 2 linking sites on, wherein in the polymerization linear structures result. In the polymerization of monomers, oligomers and / or prepolymers having 3 or more linkages In contrast, spatially crosslinked polymers result. spatial Crosslinked polymers are also used in the copolymerization of  Monomers, oligomers and / or prepolymers with one or two linkers and monomers, oligomers and / or Prepolymers with 3 linking sites obtained.

Before the structures obtained in the polymerization as well their effect on the stability of the electro-optical Systems and the solubility of the liquid crystal mixture be described in more detail, should first be the terminal Groups II be further characterized, with between terminal and nonterminal groups can be distinguished should.

a) Terminal Groups II

In the case of the terminal groups II, preferably at least one and in particular at least 2 of the radicals Y ¹ -Y ³ mean F. One or 2 of the radicals Y ¹ -Y ³ may also denote an alkyl group having 1-30 and in particular 1-20 C atoms, wherein also independently 1-15 and in particular 1-10 CH ₂ groups by -O-, -CO-, -COO-, -OCO-, -S-, -CH-halogen, C (halogen) ₂ - or substituted or unsubstituted saturated or aromatic cyclic diyl groups may be replaced, wherein O and / or S are not directly linked together. In this case, at least one of the alkyl groups preferably denotes an at least patially halogenated and in particular fluorinated alkyl, alkoxy or oxyalkyl group, the following meanings being very particularly preferred:

(O) CF₂H, (O) CFClH, (O) CF₂Cl, (O) CF₃, (O) C₂F₃H₂, (O) C₂F₄H, (O) C₂F₅, (O) C₂F₄Cl, (O) C₃F₄H₃, (O) C₃F₅H₂, (O) C₃F₃H, (O) C₃F₇, (O) C₃F₅Cl₂, (O) C₃F₃Cl₂H₂, (O) C₄F₅H₄, (O) C₃F₄H₃, (O) C₄F₇H₂, (O) C₄F₈H, (O) C₄F₉, (O) C₅F₅H₅, (O) C₅F₆H₅, (O) C₅F₇H₄, (O) C₅F₇H₃, (O) C₅F₉H₂, (O) C₅F₁₀H, (O) C₅F₁₁, (O) C₆F₈H₅, (O) C₆F₉H₄, (O) C₆F₁₀H₃, (O) C₆F₁₁H₂, (O) C₆F₁₂H, (O) C₆F₁₃, (O) C₇F₉H₆, (O) C₇F₁₀H₅, (O) C₇F₁₁H₄, (O) C₇F₁₂H₃, (O) C₇F₁₁ClH₃, (O) C₇F₁₂H₃, (O) C₇F₁₃H₂, (O) C₇F₁₄Cl, (O) C₇F₁₅, (O) C₈F₁₂H₅, (O) C₈F₁₃H₄, (O) C₈F₁₄H₃, (O) C₈F₁₅H₂, (O) C₈F₁₆H, (O) C₈F₁₇, (O) C₉F₁₅H₄, (O) C₉F₁₆H₃, (O) C₉F₁₇H₂, (O) C₉F₁₈H, (O) C₉F₁₉, (O) C₁₀F₁₈H₃, (O) C₁₀F₁₉H₂, (O) C₁₀F₁₉Cl₂, (O) C₁₀F₂₀H or (O) C₁₀F₂₁. The above particularly preferred terminal groups can be straight-chain or branched, but in particular be branched.

A particularly good solubility of the liquid crystal mixture in the precursor of the polymeric medium is observed when component A contains more than 5% and in particular not less than 10% of monomers, oligomers and / or prepolymers which have a group II in which at least 3 of the radicals Y ¹ -Y ⁵ F mean. Very particular preference is given to monomers, oligomers and / or prepolymers containing a group II, Y ¹ = Y ² = Y ³ = Y ⁴ = F or 3 of the radicals Y ¹ -Y ⁵ F and one of the other two Radicals is one of the abovementioned preferred polyfluorinated alkyl or alkoxy radicals.

b) Non-terminal group II

In the nonterminal groups II, 2 or 3, but in particular 2 of the radicals Y ¹ -Y ^{3 is} an alkylene group or a single bond which connects the group II with polymerizable radicals. Preference is given to non-terminal groups in which 2 of the 3 groups Y ¹ -Y ³ denote an alkylene group and / or a single bond and the other group F.

The terminal group II has one and the nonterminal group II has at least two radicals which each contain at least one polymerizable group which are bonded directly or via an intermediate group to the respective group II. These intermediate groups may be alkylene groups of 1-30, in particular 1-20 and very particularly 1-15 C atoms, in which in particular 1-10 CH ₂ groups independently of one another by -O-, -CO- COO -, -OCO-, -S-, -CHHalogen-, -C (halogen) ₂ - or substituted or unsubstituted saturated or aromatic cyclic Diyl Grup pen may be replaced, wherein O and / or S are not directly linked, and / or one or more single bonds. Very particular preference is given to straight-chain or branched alkylene groups having 1-10 C atoms and in particular special methylene, ethylene, 1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene, 1,7 -Heptylen, 1,8-octylene, 1,9-nonylene and 1,10-decylene.

More preferred are methylenoxy, ethyleneoxy, 1,3-propyleneoxy, 1,4-butyleneoxy, 1,5-pentyleneoxy, 1,6-hexyleneoxy, 1,7-heptyleneoxy, 1,8-octyleneoxy, 1,9-honylenoxy. Also preferred are alkylene groups having 1-10 C atoms, in which up to 3 non-adjacent CH ₂ groups are substituted by -O-, CO-, -COO- and / or -OCO-. Furthermore, the preferred groups mentioned may be monosubstituted or oligosubstituted by halogen and particularly preferably by F.

The intermediate group can also have one or more alicyclic substituted or unsubstituted saturated or aroma table cyclic 1,4-diyl groups such as. B. 1,4-cyclohexylene or 1,4-phenylene groups, the latter may also be substituted and in particular fluorinated. The incorporation of rings into the intermediate group or intermediate Groups can in particular to adjust the refractive index of the polymeric medium to one of the refractive indices of Liquid crystal mixture be advantageous. The term fluorinated, oligofluorinated or perfluorinated aliphatic Monomers, oligomers and / or prepolymers is corresponding wide and also includes connections with one Structural element II, which contains one or more cyclic Groups in the Intermediate Groups and / or in the or contain the alkyl groups.  

In the case of the polymerizable groups P, which via the intermediate groups Z to the group of Formula II are bonded, it is preferably to one of the above polymerizable groups, which have two or one point of attachment. It can only a polymerizable group P via Z to the group of Formula II be bound, schematic

(R P-Z-

or 2 or more polymerizable groups in to be contained in a residue, schematically

The polymerizable groups may be substituted or unsubstituted, here in particular the same Substituents as in the group II come into question. The Substitution is indicated schematically by (R.

Compounds of the type described which are a structural element ment of formula II and at least one polymerizable Group are in the literature as well as methods described for their preparation.  

Below are some representative examples of Acrylates are given.

Other interesting structures are z. B .:

The compounds exemplified here are intended to be Only explain the invention and not limit it. A variety of other monomers, oligomers and / or Prepolymers containing a structural element of the formula II and one or more of the polymers listed above baren groups, is described in the literature. The subject In addition, you can do more without inventive step Any combinations of the described groups P, Z and of the structural element II, wherein the production in Obviously by conventional methods of organic Chemistry takes place.

It was found that the solubility of the liquid crystal mixture which contains one or more compounds of the formula I. contains and in particular more than 15% and especially contains more than 20% of compounds of formula I in which Precursor of the polymeric medium can be significantly increased when the precursor between 0.1% and 95% of a component te contains A, which consists of one or more compounds, containing a structural element II. It will often already at a relatively low mass fraction of Component A on the precursor a significant improvement the miscibility observed. This improvement is special apparently when the precursor prepolymer contains. In such systems is often without the addition of Compounds containing a structural element of the formula II, a sufficient miscibility either not at all or only achieved at greatly elevated temperatures. In contrast, will by the addition of one or more compounds with  a structural element II often also when using Prepolymer already at room temperature or slightly increased Temperatures of z. B. less than 80 ° C, in particular Weni than 60 ° C and especially less than 40 ° C a sufficient and mostly even good solubility beo bachtet. The mass fraction of component A on the precursor is preferably more than 3% and especially not less than 5%. When using prepolymers is common a higher proportion of compounds containing a structure element of the formula II, advantageous. The usage of Prepolymer is often especially in acrylate systems preferred, since by the hardening of the system observed shrinkage can be reduced.

The increase in solubility caused by component A. the liquid crystal mixture in the precursor of the polymeric Mediums is probably explained by the fact that the verbin compounds of the formula I contain the terminal group -Q-Y and In addition, they are often fluorinated laterally, the group -Q-Y and Group II has a great structural similarity respectively.

To reduce the solubility of the liquid crystal mixture in the polymerized medium, the precursor of the Medium monomers, oligomers and / or prepolymers, which have at least 3 attachment sites. such Monomers, oligomers and / or prepolymers lead to a spatially crosslinked structure of the polymeric medium, thereby a higher long-term stability of the electro-optical Anord  tion is effected. These crosslinkers can both to monomers, oligomers and / or prepolymers of the component A, which is a structural element of the formula II and at least 3 links as well as other mono mers, oligomers and / or prepolymers with at least 3 linking sites, which is the component B form. Crosslinker containing a structural element of Formula II are described above and some acrylate compound tions are given by way of example. As an example for others Crosslinkers are divinylbenzenes, ethylene diacrylates, 1,6-hexanediol diacrylates, bisphenol A diacrylates and dimeth acrylates, trimethylolpropane diacrylates, pentaerythritol acrylates, triethylene glycol diacrylates, ethylene glycol dimeth acrylates, tripropylene glycol triacrylates, pentaerythritol tri acrylates, pentaerythritol tetraacrylates, ditrimethylpropane tetraacrylates or dipentaerythritol pentaacrylates and hexaacrylates indicated.

In addition to these di- and Oligoacrylatverbindungen are many other polymerizable monomers, oligomers and / or Prepolymers with at least 3 linking sites known. In this case, those are preferred which by combining the above-mentioned preferred polymerizable structure elements can be obtained.  

The mass fraction of the monomers, oligomers and / or Prepolymers with at least 3 linkages to the Inventive precursor of the optically transparent Media is preferably more than 5% and in particular more than 10%. Have particularly favorable properties Such precursors, their monomers, oligomers and / or Prepolymers of component A in addition to a structural element of Formula II at least partially 3 or more linkages have. Precursor containing such crosslinker with a mass fraction of more than 5% and in particular of not less than 10% are particularly preferred.

The precursor must be selected beyond the previously described requirements so that the refractive index of the polymer optically transparent medium substantially coincides with one of the refractive indices of the liquid crystal mixture, generally the normal refractive index n _o . The optical properties of the monomers, oligomers and / or prepolymers of component A can be varied within a relatively wide range by the described structural variations, in particular of the substituents Y ¹ -Y ⁵ . In addition, the precursor can be added crosslinker of the compo nent B and other polymierisierbare monomers, oligomers and / or prepolymers, which can be readily selected by the skilled person so that the optical adjustment of the refractive indices is optimized.

The polymerization may be polymerized depending on the nature of the polymer baren groups proceed according to different mechanisms, whereby photoradical and photocationic and in particular Photoradikalischen Polynierisationsprozesse are preferred.  

Particularly suitable radical-forming photoinitiators are in DE 41 04 183 described while advantageous cations forming photoinitiators are described in JP 2-4 09 225.

To optimize the properties of the cured polymer It is often advantageous that the precursor of more than a monomer, oligomers and / or prepolymers. The copolymerizable components of the Precursors both the same and different poly have merizable groups. So z. B. acrylate Systems containing several components with one or several acrylate groups, often preferred as a precursor. Furthermore, those precursors, which in addition to a or more acrylate components, for. Other olefinic unsaturated monomers, oligomers and / or prepolymers such as z. As vinyl esters, styrenes, etc., often by particularly advantageous properties. When Further examples are the copolymerization of olefinic mono- or polyunsaturated components of the precursor with di- or polythiols and / or di- or polyalcohols and / or with olefinically unsaturated monomers, oligomers and / or prepolymers, which additionally have one or more -OH and / or -SH groups. The Precursor systems described here are exemplary too understand and should only explain the invention, without to limit them. The expert can easily on the Basis of the present description further precursor with specify other compositions so that the properties the precursor and in particular the cured polymer Medium with regard to the respective requirements opti are mingled.  

The mixture of the olefinically unsaturated precursor and the liquid crystal mixture may optionally further Additions include such. As antioxidants, Lichtstabili if necessary, crosslinker for increasing the degree of crosslinking etc. These additives should have the highest possible specifi c have resistance and cleaned accordingly his. Since such additives often only in small or very low concentrations, which are significantly lower can be added as the initiator concentration sometimes a relatively low value for the specifi resistance can be tolerated without the HR of the electro-optical system sinks too much; this is especially true This is the case when the concentration of additives is related on the mass of the overall system, less than 1.0% and especially less than 0.5%.

The in the electro-optical systems according to the invention used liquid crystal mixtures can Verbin in addition to compounds of the formula I also nitrile compounds of the formulas III-VI included

wherein
each independently of one another an alkyl group having 1-15 C atoms, in which also one or two non-adjacent CH₂ groups may be replaced by -O-, -CO- and / or -CH = CH,
V is a single bond; -COO- or -OOC-,

mean.

However, it has been found that systems according to the invention, whose liquid-crystal mixture contains more than 15% of nitrile compound often due to an insufficient HR value Marked are.

The related to the mass of the liquid crystal mixture Proportion of nitrile compounds is preferably small and especially not higher than 10% and especially not higher than 7.5%. Systems according to the invention, their liquid crystal mixtures do not contain nitrile compounds are very particularly preferred.  

The proportion of the compounds of the formula I to the invention According to liquid crystal mixtures used is preferably not too small and is in particular more than 10% and especially more than 20%. Liquid crystal mixtures, containing more than 40% and in particular not less than 50% of compounds of the formula I are particularly preferred.

The liquid crystal mixtures used according to the invention may contain other ingredients, preferably be selected from nematic or nematogenic (monotro pen or isotropic) substances, especially substances from the classes of azoxybenzenes, benzylideneanilines, biphenyls, Terphenyls, phenyl or cyclohexyl benzoates, cyclohexanecar bonsäurephenyl- or cyclohexyl esters, phenyl or cyclo hexyl esters of cyclohexylbenzoic acid, phenyl or cyclo hexyl ester of cyclohexylcyclohexanecarboxylic acid, cyclohexyl phenyl ester of benzoic acid, cyclohexanecarboxylic acid, or cyclohexylcyclohexanecarboxylic acid, phenylcyclohexanes, Cyclohexylbiphenyls, phenylcyclohexylcyclohexanes, cyclo hexylcyclohexanes, cyclohexylcyclohexenes, cyclohexylcyclo hexylcyclohexenes, 1,4-bis-cyclohexylbenzenes, 4,4'-bis-cyclo hexylbiphenyls, phenyl- or cyclohexylpyrimidines, phenyl- or cyclohexylpyridines, phenyl- or cyclohexyl-dioxanes, Phenyl or cyclohexyl-1,3-dithiane, 1,2-diphenylethane, 1,2-dicyclohexylethane, 1-phenyl-2-cyclohexylethane, 1-Cyclohexyl-2- (4-phenyl-cyclohexyl) -ethanes, 1-cyclohexyl-2 biphenylylethane, 1-phenyl-2-cyclohexylphenylethanes, given optionally halogenated stilbenes, Renzylphenylether, tolans and substituted cinnamic acids. The 1,4-phenylene groups in these compounds may also be fluorinated.  

The in the electro-optical systems according to the invention used liquid crystal mixtures preferably contain also one or more dielectrically neutral compounds Formulas 1-5:

R '' - L-E-R '' 1 R '' - L-COO-E-R '' 2 R '' - L-OOC-E-R '' 3 R '' - L-CH₂CH₂-E-R '' 4 R '' - L-C = C-E-R '' 5

In formulas 1, 2, 3, 4 and 5, L and E are the same or may be different, each independently a bivalent radical from the group consisting of -Phe-, -Cyc-, -Phe-Phe-, -Phe-Cyc, -Cyc-Cyc, -Pyr-, -Dio, -G-Phe and -G-Cyc and their mirror images formed group, wherein Phe unsubstituted or substituted by fluorine 1,4-phenylene, Cyc trans-1,4-cyclohexylene or 1,4-cyclo hexenylene, Pyr pyrimidine-2,5-diyl or pyridine-2,5-diyl, Dio 1,3-dioxane-2,5-diyl and G 2- (trans-1,4-cyclohexyl) ethyl, pyrimidine-2,5-diyl, pyridine-2,5-diyl or 1 3-dioxane-2, 5-diyl.

Preferably one of the radicals L and E is Cyc, Phe or Pyr. e is preferably Cyc, Phe or Phe-Cyc. Preferably ent th the liquid crystals according to the invention one or more Components selected from the compounds of the formulas 1, 2, 3, 4 and 5, wherein L and E are selected from the group  Cyc, Phe and Pyr and at the same time one or more compo selected from the compounds of the formulas 1, 2 '3, 4 and 5, wherein one of the radicals L and E is selected from the group Cyc, Phe and Pyr and the other radical selected is from the group -Phe-Phe-, -Phe-Gyc-, -Cyc-Cyc-, -G-Phe and -G-Cyc-, and optionally one or more components selected from the compounds of the formulas 1, 2, 3, 4 and 5, wherein the radicals L and E are selected from the Group -Phe-Cyc, -Cyc-Cyc, -G-Phe and -G-Cyc-.

R '' 'and R' 'in the compounds of sub-formulas 1a, 2a, 3a, 4a and 5a are each independently preferred Wise alkyl, alkenyl, alkoxy, alkenyloxy or alkanoyloxy with up to 8 carbon atoms. For most of these Compounds R '' and R '' are different from each other, wherein one of these radicals, in particular alkyl, alkoxy or alkenyl is.

The mass fraction of the compounds of formulas 1-5 to the Liquid crystal used in the invention preferably 0-50% and especially 0-40%.

The in the electro-optical systems according to the invention used liquid crystal mixtures preferably contain 1-98%, in particular 5-95% of compounds of the formula I. The liquid crystals preferably contain 1-20, in particular but 1-15 and especially 1-12 compounds of Formula I.  

The expert can select from the large pool of nematic or nematic substances additives to the described liquid-crystal mixtures so that the birefringence Δn and / or the ordinary refractive index n _o and / or other refractive indices and / or the viscosity and / or the dielectric anisotropy and / or other parameters of the liquid crystal can be optimized with regard to the respective application.

The electro-optical systems according to the invention are characterized by favorable values for the threshold voltage and the slope the electro-optical characteristic and a high UV and Temperature stability, high contrast and in particular by a high HR - even at elevated temperatures and under UV irradiation - a low solubility of Liquid crystal mixture in the polymeric medium and a high long-term stability characterized.

The in the control of Mikrorotröpfchen- or Netzwerksy be problems with an active matrix of the electro-optical system according to the invention better solved as in previously described such arrangements.  

The following examples are intended to illustrate the invention without to limit them.

example 1

A liquid crystal mixture containing

10% of 4- (trans-4-pentylcyclohexyl) benzonitrile
8% 4- (trans-4-hexylcyclohexyl) benzonitrile
6% 4- (trans-4-heptylcyclohexyl) benzonitrile
8% 4- (trans-4- (trans-4-ethylcyclohexyl) cyclohexyl) -1-trifluoromethoxybenzene
12% 4- (trans-4- (trans-4-propylcyclohexyl) cyclohexyl) -1-trifluoromethoxybenzene
7% 4- (trans-4- (trans-4-butylcyclohexyl) cyclohexyl) -1-trifluoromethoxybenzene
11% 4- (trans-4- (trans-4-pentylcyclohexyl) cyclohexyl) -1-trifluoromethoxybenzene
12% 4- (trans-4-propylcyclohexyl) -3 ', 4'-difluorobiphenyl
10% of 4- (trans-4-pentylcyclohexyl) -3 ', 4'-difluorobiphenyl
5% 1- (trans-4- (trans-4-propylcyclohexyl) cyclohexyl) -2- (4-trifluoromethoxyphenyl) -ethane
5% 1- (trans-4- (trans-4-pentylcyclohexyl) cyclohexyl) -2- (4-trifluoromethoxyphenyl) -ethane
2% 2-fluoro-4- (trans-4-propylcyclohexyl) -4'-propylcyclohexylbiphenyl
2% 2-fluoro-4- (trans-4-pentylcyclohexyl) -4'-propylcyclohexylbiphenyl
2% 2-fluoro-4- (trans-4-pentylcyclohexyl) -4'-pentylcyclohexylbiphenyl

is treated with hexanediol diacrylate, 1H, 1H-heptafluorobutylmeth acrylate, dipentaerythritol pentaacrylate and benzil dimethyl ketal in the weight ratio 50: 32.5: 10: 5: 2.5 at Room temperature mixed and together with spacers (20 μm) between 2 transparent, with electrode layers brought glass substrates, creating a film with a Thickness of 20 μm is obtained by UV irradiation (30 W UV lamp) is cured. One of the electrode layers is designed as an active TFT matrix, while the other Electrode represents the counter electrode.

Claims (7)

1. electro-optical system,

• which contains a liquid-crystal mixture and a further optically transparent polymeric medium between two electrode layers, one of the electrode layers being formed as an active matrix with non-linear drive elements integrated in the pixel, while the other electrode layer forms the counterelectrode,
• whose liquid crystal molecules have an irregular orientation when switched off,
• - Wherein one of the refractive indices of the liquid crystal mixture substantially coincides with the refractive index of the polymeric medium n _M and / or in which the quotient of the mass of the liquid crystal mixture and the mass of the optically transparent medium is 1.5 or more,
• - Which in one of the two switching states regardless of the polarization of the incident light has a relation to the other state reduced transmission,

characterized

• - That the liquid crystal mixture contains one or more compounds of the formula I. wherein
  Z¹ and Z² are independently a single bond, -CH₂CH₂-, -COO-, -OCO- or -C≡C-, independently of one another trans-1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene or 3, 5-difluoro-1,4-phenylene and one of also pyrimidine-2,5-diyl, pyridine-2,5-diyl or trans-1,3-dioxane-2,5-diyl,
  X¹, X², X³ and X⁴ are independently H or F,
  Q is CF₂, OCF₂, C₂F₄, OC₂F₄ or a single bond,
  YH, F or Cl,
  n 0, 1 and 2 and
  R is alkyl having up to 12 C atoms, in which also one or two non-adjacent CH ₂ groups may be replaced by -O- and / or -CH = CH-,
  mean, and
  in that the precursor of the medium for increasing the solubility of the liquid-crystal mixture in the precursor contains between 0.1% and 95.0% of a component A consisting of one or more fluorinated, oligo-fluorinated or perfluorinated aliphatic mono mers, oligomers and / or prepolymers consists.

2. Electro-optical system according to claim 1, characterized in that component A is based on monomers, oligomers and / or prepolymers which have a structural element of the formula II wherein
up to 2 of Y ¹ , Y ² and Y ³ independently of each other H or F, at least one and up to 3 of the radicals Y ¹ -Y ³ inde pendently of each other, an alkylene group having 1-30 C atoms, wherein also 1-15 CH ₂ groups are each independently substituted by -O-, -CO-, -COO-, -OCO-, -S-CHHalogen-, -C (halogen) ₂ - or substituted or unsubstituted saturated or aromatic cyclic diyl groups where O and / or S are not directly linked, and / or a single bond, and
up to 2 of the radicals Y ¹ -Y ³ an alkyl group having 1-30 C atoms, wherein also 1-15 CN ₂ groups each independently of one another by -O-, -CO-, -COO-, -OCO-, - S, -CHHalogen-, -C (halogen) ₂ - or substituted or unsubstituted saturated or aromatic cyclic diyl groups may be replaced, wherein O and / or S are not directly linked together. 3. Electro-optical system according to one of claims 1 or 2, wherein the monomers, oligomers and / or prepolymers the component A to achieve a low solubility keit the liquid crystal mixture in the polymeric Medium at least partially 3 or more linkage have and / or wherein the precursor between Contains 0.1% and 75.0% of a component B, which consists of one or more monomers, oligomers and / or Prepolymers each having at least 3 linking exists.   4. Electro-optical system according to one of claims 1-3, characterized in that the monomers, oligomers and / or prepolymers of component A and B photoradi kalisch and / or photocationic polymerizable Have groups. 5. Mixture for the production of an electro-optical system according to any one of claims 1-4, containing one Liquid crystal mixture containing at least one verbin of the formula I, and a precursor of Medium, which at least one component A and a Component B has. 6. Use of a mixture according to claim 5 for the manufacture Development of an electro-optical system according to one of Claims 1-4.