EP0354940A1 - Improved liquid crystal mixture - Google Patents

Improved liquid crystal mixture

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Publication number
EP0354940A1
EP0354940A1 EP89901058A EP89901058A EP0354940A1 EP 0354940 A1 EP0354940 A1 EP 0354940A1 EP 89901058 A EP89901058 A EP 89901058A EP 89901058 A EP89901058 A EP 89901058A EP 0354940 A1 EP0354940 A1 EP 0354940A1
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Prior art keywords
liquid crystal
trans
crystal material
another
replaced
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German (de)
French (fr)
Inventor
Bernhard Scheuble
Takamasa Oyama
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Merck Patent GmbH
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Merck Patent GmbH
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00—Liquid crystal materials
    • C09K19/02—Liquid crystal materials characterised by optical, electrical or physical properties of the components, in general
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/42—Mixtures of liquid crystal compounds covered by two or more of the preceding groups C09K19/06 - C09K19/40
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00—Liquid crystal materials
    • C09K19/02—Liquid crystal materials characterised by optical, electrical or physical properties of the components, in general
    • C09K19/0208—Twisted Nematic (T.N.); Super Twisted Nematic (S.T.N.); Optical Mode Interference (O.M.I.)

Abstract

Afficheur perfectionné à cristaux liquides nématiques twistés fonctionnant en mode multiplexe élevé, présentant un fort contraste et contenant un mélange de cristaux liquides qui présente un rapport des constantes élastiques K3/K1 aussi faible que possible mais non supérieur à 0,9 et un rapport de DELTA)/epsilonorthogonale maximal de +0,3 et comprend au moins trois matériaux à cristaux liquides: (a) au moins 10 % en poids d'un premier matériau à cristaux liquides renfermant au moins un des composés de cristaux liquides représentés par la formule générale (I) dans laquelle R1 représente un groupe R ou OR; et R2 représente R ou OR; R étant dans chaque cas indépendamment un groupe alkyle à chaîne droite ayant jusqu'à 12 atomes de carbone, un ou deux groupes CH2 non adjacents pouvant être remplacés par -O- et/ou -CH=CH-, deux atomes d'oxygène n'étant pas directement combinés l'un à l'autre, A est 1,4-phénylène ou trans-1,4-cyclohexylène, Z1 est -CO-O-, -O-CO-, -CH2-O-, -OCH2-, -CH2CH2- ou bien une simple liaison, Q1 est 1,4-phénylène ou trans-1,4-cyclohexylène, et m vaut 0, 1, ou 2, (b) moins de 10 % en poids d'un deuxième matériau à cristaux liquides renfermant un ou plusieurs composés de cristaux liquides présentant une anisotropie diélectrique positive distincte (DELTA) +3); et, (c) moins de 90 % en poids d'un troisième matériau à cristaux liquides renfermant au moins un composé de cristaux liquides présentant une anisotropie diélectrique négative ou pratiquement nulle, ou (1) le premier matériau à cristaux liquides comprend au moins un des composés de cristaux liquides représentés par les formules générales (Ib) à (Ii), et/ou (2) le troisième matériau à cristaux liquides comprend au moins un composé de cristaux de liquides représenté par les formules générales (IIId) à (IIIh), (III6) à (III15) et/ou (III16) et (III17).Advanced twisted nematic liquid crystal display operating in high multiplex mode, with high contrast and containing a mixture of liquid crystals which has a ratio of the elastic constants K3 / K1 as low as possible but not more than 0.9 and a ratio of DELTA ) / epsilonorthogonal maximum of +0.3 and comprises at least three liquid crystal materials: (a) at least 10% by weight of a first liquid crystal material containing at least one of the liquid crystal compounds represented by the general formula (I) in which R1 represents an R or OR group; and R2 represents R or OR; R being in each case independently a straight chain alkyl group having up to 12 carbon atoms, one or two non-adjacent CH2 groups which can be replaced by -O- and / or -CH = CH-, two oxygen atoms n '' not being directly combined with each other, A is 1,4-phenylene or trans-1,4-cyclohexylene, Z1 is -CO-O-, -O-CO-, -CH2-O-, - OCH2-, -CH2CH2- or a single bond, Q1 is 1,4-phenylene or trans-1,4-cyclohexylene, and m is 0, 1, or 2, (b) less than 10% by weight of a second liquid crystal material containing one or more liquid crystal compounds having a distinct positive dielectric anisotropy (DELTA) +3); and, (c) less than 90% by weight of a third liquid crystal material containing at least one liquid crystal compound having a negative or substantially zero dielectric anisotropy, or (1) the first liquid crystal material comprises at least one liquid crystal compounds represented by the general formulas (Ib) to (Ii), and / or (2) the third liquid crystal material comprises at least one liquid crystal compound represented by the general formulas (IIId) to (IIIh ), (III6) to (III15) and / or (III16) and (III17).

Description

Improved Liquid Crystal Mixture
The invention relates to the improvement of a twisted nematic liquid crystal display device operating in the high multiplex mode with a very high contrast and with a particularly steep electro-optical characteristic. The device is operating in the first Gooch and Tarry transmission minimum. The invention furthermore relates to new liquid crystal dielectrics which have a ratio of the elastic constants K3/K1 as small as possible but not more than 0.9 and a ratio of Δε/ε of at most 0.3. Such, dielectrics are used in the matrix. type liquid crystal display devices driven by time sharing according to the invention.
The properties of nematic or nematic-cholesteric liquidcrystalline materials are utilized for liquid-crystal display elements in order to effect significant changes in their optical properties, such as light transmission, light scattering, birefringence, reflectance or color, under the influence of electric fields. The functioning of display elements of this type is based here, for example, on the phenomena of dynamic scattering, the deformation of aligned phases or the Schadt-Helfrich effect in the twisted cell.
Among these usual types of liquid-crystal display elements, especially those based on the twisted nematic cell (TN cell) have gained particular importance recently, because they can be operated with relatively low control voltages which can be readily made available even by small batteries. Moreover, these display elements have hitherto been the best which can be constructed as matrix display elements, which allow the presentation of a high information density without an intolerably large number of control lines, lead-ins and lead-outs. When used in practice, however, the TN cell, in particular in the form of matrix display elements, still raises considerable difficulties. These include above all the more or less pronounced dependence of the contrast on the angle of observation and the restricted multiplexing capacity.
Conventional dielectrics for TN cells have a ratio of the elastic constants K3/K1 of approximately 1.2-1.3 and Δε/ε above 1.0. Such conventional liquid crystal compositions are widely used in commercial twisted nematic display devices and disclosed in many references, e.g. Published Unexamined Japanese Patent Applications No. 56-105 510 and 56-105 511 and U.S. Patent 4,285,829. In these compositions, design is made based on the concept that the proportion of liquid crystal compounds having a distinct positive dielectric anisotropy generally is 30 % or more. These compositions are characterized in that the threshold voltages are in the range of 1 to 2 volts in most cases.
It has now been surprisingly found that when values of Δε/ε and K3/K1 of liquid crystal dielectrics become extremely small in time sharing-driven liquid crystal display devices, response speed and γ property (the sharpness in voltage-luminance property) are markedly improved in such a range of d.Δn that does meet the requirements for the first Gooch and Tarry minimum. The liquid crystal dielectrics are most suited for use in liquid crystal display devices operating in the high multiplex mode and having a surprisingly improved contrast. It is an object of the invention to provide improved display devices, in which both a markedly improved contrast, and, simultaneously, also a high response speed are ensured by operating the display elements in the first transmission minimum according to Gooch and Tarry.
Upon further study of the specification and appended claims, further objects and advantages of this invention will become apparent to those skilled in the art.
It has now been found that, with a suitable choice of the liquid crystal parameters, it is possible, surprisingly, to obtain the desired properties by operating the display elements in the first transmission minimum.
A subject of the invention, therefore, is the improvement of a twisted nematic liquid crystal display device operating in the high multiplex mode and having a high contrast, wherein the liquid crystal dielectric has a ratio of the elastic constants K3/K1 as small as possible but not more than 0.9 and a ratio of Δε/ε of at most +0.3 and comprises at least three liquid crystal materials:
(a) at least 10 wt% of a first liquid crystal material comprising at least one of liquid crystal compounds represented by general formula:
wherein R1 represents a group R or OR; and R2 represents R or OR; R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- and/or -CH=CH-, two oxygen atoms not being directly attached to one another, A is 1,4-phenylene or trans-1,4-cyclo- hexylene, Z1 is -CO-O-, -O-CO-, -CH2-O-, -OCH,-, -CH--CH^--or a single bond, Q1 is 1,4-phenylene or trans-1,4-cyclohexylene, and m. is 0, 1 or 2,
(b) less than 10 wt% of a second liquid crystal material comprising one or more liquid crystal compounds having a distinct positive dielectric aniso- tropy (Δε ≧ + 3); and,
(c) less than 90 wt% of a third liquid crystal material comprising at least one liquid crystal compound having a negative or substantially O dielectric anisotropy,
the improvement wherein
(1) the first liquid crystal material comprises at least one of liquid crystal compounds represented by general formulae lb to Ii:
wherein R1 represents a group Ror OR; and R2 represents R or OR; R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- and/or -CH=CH-, two oxygen atoms not being directly attached to one another,
and/or
(2) the third liquid crystal material comprises at least one liquid crystal compound represented by the general formulae Illd to Illh, III6 to III15 and/or III16 and III17:
wherein R11, R13, R15 and R18 each independently represent R, and R9, R10, R12, R14, R16 and R17 each independently represent R or OR,
R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another and A4 is 1,4-cyclohexenylen,
wherein R29, R31, R33, R35, R37, R39, R40, R41 R43, R45, R46, R47, and R48 each independently represent R, R30, R32, R34, R36, R38, R42 and R 44 each independently represent R or OR,
R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another, and A4 is 1,4-cyclohexenylen,
wherein R49, R50, R51 and R52 each represent R,
R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by
-O- or -CH=CH-, two oxygen atoms not being directly attached to one another.' A further subject of the invention is a method of simultaneously minimizing the dependence of contrast on the angle of observation of an electro-optical display element based on a liquid crystal dielectric and of maximizing its multiplexing capacity by maximizing its steepness of its characteristic curve, comprising operating the element in the first Gooch and Tarry transmission minimum, selecting a dielectric as outlined above.
The construction of the liquid crystal display element according to the invention from polarizers, electrode base plates and electrodes with such a surface treatment that the preferential orientation of the particular adjoining liquid crystal molecules is usually twisted by 90° from one electrode to the other, corresponds to the type of construction conventional for such display elements. The concept of the conventional type of construction is here taken in a very wide sense and also comprises all the variations and modifications, known from the literature, of the twisted nematic cell, and in particular also matrix display elements. An essential difference between the display elements according to the invention and those hitherto conventional and based on the twisted nematic cell is, however, the choice of the liquid crystal parameters in the liquid crystal layer. Whereas, for example, the K3/K1 ratio in the conventional liquid-crystalline phases for display elements of this type is at least > 0.8 and the Δε/ε ratio is normally between 1.2 and 1.7, the K3/K1 ratio in the display elements according to the invention is ≦ 0.9 and Δε/ε is ≦ 0.3. The K3/K1 ratio in the display ele ments according to the invention preferably is 0.4 to 0.9 and Δε/ε preferably is 0.4 to 0.3. Particularlypreferred dielectrics are those, wherein K3/K1 is 0.2 to 0.75 and Δε/ε is 0.1 to 0.3. The parameters used to define the invention are fully known to skilled workers. The contemplated definitions are to be found in many publications, e.g. W.H. De Jeu, Physical Properties of Liquid Crystal Materials, Gordon and Breach 1980 and the brochure "Liquid Crystals, Measurement of the Physical Properties" of E. Merck, whose disclosures are incorporated by reference herein.
The thickness of a liquid crystal layer of the display element according to the invention and/or the optical anisotropy Δn of the liquid crystal material are chosen such that
the value of 550 nm, normally used for the maximum sensitivity of the human eye, being taken for the wavelength λ. The layer thicknesses of the display elements according to the invention can, for example, be within the range from 2 to 10 μm. Preferably, the smallest possible layer thicknesses are chosen, the lower limit of d being determined by the quality standards rrquired for mass production. A particularly preferred range of d is thus 3 to 8 μm, in particular 4 to 7 μm.
Liquid-crystalline dielectrics, the material parameters of which are within the ranges according to the invention, can be prepared from conventional liquid-crystalline base materials. Numerous such materials are known from the literature. The dielectrics used for the display elements according to the invention comprise (a) at least 10 wt% of a first liquid crystal material comprising at least one of liquid crystal compounds represented by general formula:
wherein R1 represents a group R or OR; and R2 represents R or OR; R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- and/or -CH=CH-, two oxygen atoms not being directly attached to one another, A is 1 ,4-phenylene or trans-1,4-cyclohexylene, Z1 is -CO-O-, -O-CO-, -CH2-O-, -OCH2-, -CH2CH2- or a single bond, Q is 1,4-phenylen or trans-1,4-cyclohexylene, and m is 0, 1 or 2,
(b) less than 10 wt% of a second liquid crystal material comprising one or more liquid crystal compounds having a distinct positive dielectric anisotropy (Δε ≧ + 3); and,
(c) less than 90 wt% of a third liquid crystal material comprising at least one liquid crystal compound having a negative or substantially 0 dielectric anisotropy, whereby (1) the first liquid crystal material comprises at least one of liquid crystal compounds represented by general formulae lb to li:
wherein R1 represents a group R or OR; and R2 represents R or OR; R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- and/or -CH=CH-, two oxygen atoms not being directly attached to one another,
and/or
(2) the third liquid crystal material comprises at least one liquid crystal compound represented by the general formulae Illd to Illh, III6 to III15 and/or III16 and III17:
wherein R11, R13, R15 and R18 each independently represent R, and R9, R10, R12, R14, R16 and R 17 each independently represent R or OR,
R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another and A 4 i.s 1,4-cyclohexenylen,
where in R29 , R31 , R33 , R35 , R37 , R39 , R40 , R41 R43, R45, R46, R47, and R48 each independently represent R, R30 , R32, R34, R36, R38, R42 and R 44 each independently represent R or OR,
R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another, and A4 is 1,4-cyclohexenylen,
wherein R 49, R50, R51 and R52 each represent
R, R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent
CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another.
Preferably the dielectric comprises at least one liquid crystal compound represented by the general formula la
Preferably the second liquid crystal material comprises at least one of liquid crystal compounds represented by the general formulae Ila to lId:
X being hydrogen or fluorine, Y being cyano, trifluoromethoxy or fluorine, r being 0 or 1, and R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another.
The third liquid crystal material comprises preferably liquid crystal compounds having a dielectric anisotropy of -1 to +1.
Preferably the third liquid crystal material comprises at least one of liquid crystal compounds represented by the general formulae IlIa to IIIc; wherein R 3 represents R; and R4 represents R or OR
wherein R5 represents R; and R6 represents R or OR
wherein R 7 represents R; and R8 represents R or OR;
R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another.
Other preferred dielectrics are those, wherein the third liquid crystal material further comprises at least one of liquid crystal compounds represented by general formulae:
wherein R 19 and R20 represent independently from one another R
wherein R 21 and R22 represent mdenpendehtly from one another R;
wherein R 23 and R24 represent independently from one another R;
wherein R25 and R26 represent independently from one another R;
wherein R27 and R28 represent independently from one another R; and n is 0 or 1; R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another.
In the following tables appropriate liquid crystal compounds are shown with their physical properties. These compounds can be used for example for the display elements according to the invention.
Compounds of formulae la, lb, Ic, Ie, If and Ig are listed in Table 1. R1 preferably is n-alkyl having
3 to 9 carbon atoms. R2 preferably is ethyl, n-propyl or n-alkoxy having 5 to 9 carbon atoms.
In addition pyrimidines of formula la are preferred wherein R 2 is methoxy.
Representative compounds of the second liquid crystal material (general formulae Ila to Ilh) with a distinct positive dielectric anisotropy are shown in Table 2.
As the liquid crystal compound having a negative or substantially 0 Δε value, there can be used liquid crystal compounds of phenylcyclohexane type represented by general formula IlIa (German Patent 26 36 684), phenyl cyclohexane carboxylates represented by general formula nib (German Patent 24 29 093), cyclohexyl cyclohexanes (USP 4,622,164) represented by general formula IIIc, biphenylcyclohexanes - formula Illl - (Japanese Patent 1,311,608), phenyl cyclohexylcyclohexane carboxy- lates - formula Ill2 - (Japanese Patent 1,297,121),
1-phenyl-2-cyclohexylcyclohexylethanes - formula Ill3 - (USP 4,606,845), cyclohexyl cyclohexylcyclohexane carboxylates - formula Ill4 - (Japanese Patent 1,297,121), 4,4'-biscyclohexylbiphenyls (USP 4,331,552) and 4,4'- biscyclohexyl-2-fluorbiphenyls (USP 4,419,264) - formula III5 -. These liquid crystal compounds are low viscosity liquid crystal compounds for controlling viscosity, high temperature liquid crystal for raising N-I point and liquid crystals for suppressing smectic phases. As low viscosity liquid crystal compounds, there can be used liquid crystal compounds shown in Table 3 which show η of approximately 6 to 20 mPa.s.
As high temperature liquid crystals, there can be used liquid crystal compounds shown in Table 4 having N-I point of approximately 130 to 330 °C. η is approximately 13 to 65 mPa.s.
In all components of the liquid crystal compositions according to this invention R is preferable alkyl of 1 to 10 carbon atoms. A particularly preferred range is 1 to 5 carbon atoms.
At least one of the liquid crystal compounds shown in these Tables 3 and 4 or at least one of the compounds of general formulae Illd to Illh and III6 to III17 may be used for said third liquid crystal material.
Preferred devices according to the invention are those, wherein the liquid crystal dielectric comprises at least five components. Preferred embodiments are those, wherein
- the liquid crystal mixture is adjusted for a device, operating in the first Gooch and Tarry transmission minimum.
- the liquid crystal mixture is adjusted for a device, wherein the electro-optical characteristic curve is at least as steep as that curve in the second such transmission minimum. - the liquid crystal mixture is adjusted for a device, wherein the steepness of the characteristic curve in the first minimum is greater than that in the second minimum.
- the liquid crystal mixture shows K3/K1 of 0.4 to 0.9 and Δε/ε is 0.4 to -0.3.
- the liquid crystal mixture shows K3/K1 of 0.2 to 0.75 and Δε/ε is 0.1 to 0.3. - the liquid crystal mixture comprises at least five components. - the first liquid crystal material comprises at least one of liquid crystal compounds represented by the general formula la
the second liquid crystal material comprises at least one of liquid crystal compounds represented by the general formulae Ila to lId:
X being hydrogen or fluorine, Y being cyano, trifluoromethoxy or fluorine, r being 0 or 1 and R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another.
the third liquid crystal material comprises liquid crystal compounds having a dielectric anisotropy of -1 to +1. the third liquid crystal material comprises at least one of liquid crystal compounds represented by the general formulae IlIa to IIIc;
wherein R 3 represents R; and R4 represents R or OR
wherein R 5 represents R; and R6 represents R or OR
wherein R7 represents R; and R8 represents R or OR;
R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another.
the third liquid crystal material further comprises at least one of liquid crystal compounds represented by general formulae:
wherein R19 and R20 represent independently from one another R
wherein R 21 and R22 represent indenpendently from one another R;
wherein R 23 and R24 represent independently from one another R;
wherein R25 and R26 represent independently from one another R;
wherein R 27 and R28 represent independently from one another R; and n is 0 or 1; R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another.
- the formulation ratios of said first liquid crystal material, said second liquid crystal material and said third liquid crystal material are at least 30 wt%, less than 10 wt% and less than 70 wt%, respectively.
- the formulation ratios of said first liquid crystal material, said second liquid crystal material and said third liquid crystal material are 30 to 65 wt%, less than 5 wt% and 35 to 70 wt%, respec- tively.
Preferred dielectrics are those, wherein the formulation ratios of said first liquid crystal material, said second liquid crystal material and said third liquid crystal material are at least 30 wt%, less than 10 wt% and less than 70 wt%, respectively.
Particularly preferred dielectrics are those, wherein the formulation ratios of said first liquid crystal material, said second liquid crystal material and said third liquid crystal material are 30 to 65 wt%, less than 5 wt% and 35 to 70 wt%, respectively.
Such dielectrics can additionally contain dyes and/or doping substances in the usual quantities, unless the liquid crystal parameters are thus taken out of the ranges according to the invention. Mixing of the liquid crystalline components to achieve the parameters discussed above can be routinely accomplished by the usual preliminary orientation experiments taking into account the usual considerations. Some of the many publications, whose disclosures are incorporated by reference herein, disclosing details of suitable materials include German Offenlegungsschrift 2,257,588; 2,306,738; 2,017,727; 2,321,632; European Published Application 0,126,883; USP 3,997,536; 4,062,798; 4,462,923; 4,389,329; 4,364,838; 4,066,570; 4,452,718; 4,419,262; 4,510,069; Japanese Published Applications 144,770/84; 144,771/84; 144,772/8443,961/83; D. Demus et al., Flϋssige Kristalle in Tabellen, VEB Deutscher Verlag fur Grundstoffindustrie, Leipzig 1974 and D. Demus et al., Flϋssige Kristalle in Tabellen II, VEB Deutscher Verlag fur Grundstoffindustrie, Leipzig 1984. All components are known or can be prepared in analogy to known compounds.
Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The following preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. In the tables 1-4 above and in the following examples, all temperatures are set forth uncorrected in degrees Celsius; unless otherwise indicated, all parts and percentages are by weight. Example 1
A liquid crystalline phase consisting of
2 % 2-(3',4'-difluorobiphenyl-4-yl)-5-heptylpyrimidine, 11 % trans-1-p-propylphenyl-4-pentylcyclohexane, 9 % trans-1-p-ethoxyphenyl-4-propylcyclohexane, 7 % trans-1-p-butoxyphenyl-4-propylcyclohexane, 7 % 2-p-ethylphenyl-5-propylpyrimidine, 7 % 2-p-propylphenyl-5-propylpyrimidine, 5 % 2-p-pentyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-heptylpyrimidine, 9 % 1-[trans-4-(trans-propylcyclohexyl)-cyclohexyl]- 2-(p-methylphenyl)-ethane,
9 % 1- [trans-4-(trans-propylcyclohexyl)-cyclohexyl]- 2-(p-propylphenyl)-ethane, 9 % 1-[trans-4-(trans-propylcyclohexyl)-cyclohexyl]- 2-(p-pentylphenyl)-ethane and
5 % 4-nonyl-4'-(trans-4-pentylcyclohexyl)-biphenyl
has a clearing point of 60.6°, Δε = 0.6 and Δn = 0.127. Example 2
A liquid crystalline phase consisting of
2 % 2-p-fluorophenyl-5-hexylpyrimidine,
11 % trans-1-p-propylphenyl-4-pentylcyclohexane,
9 % trans-1-p-ethoxyphenyl-4-propylcyclohexane,
7 % trans-1-p-butoxyphenyl-4-propylcyclohexane,
7 % 2-p-ethylphenyl-5-propylpyrimidine, 7 % 2-p-propylphenyl-5-propylpyrimidine, 5 % 2-p-pentyloxyphenyl-5-hexylpyrimidme, 5 % 2-p-heptyloxyphenyl-5-hexylpyrimidme, 5 % 2-p-nonyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-heptylpyrimidine,
9 % 1-[trans-4-(trans-propylcyclohexyl ) -cyclohexyl] - 2- (p-methylphenyl ) -ethane, 9 % 1-[trans-4- (trans-propylcyclohexyl ) -cyclohexyl] - 2- (p-propylphenyl )-ethane, 9 % 1- [trans-4- (trans-propylcyclohexyl)-cyclohexyl] - 2- (p-pentylphenyl )-ethane and 5 % 4-nonyl-4 ' -(trans-4-pentylcyclohexyl )-biphenyl
has a clearing point of 57.8° , Δε = 0.5 and Δn = 0.125.
Example 3
A liquid crystalline phase consisting of
3 % trans-4-(trans-4-propylcyclohexyl)-1-methoxycyclohexane, 3 % trans-4-(trans-4-propylcyclohexyl)-1-propoxycyclohexane,
2 % 2-p-fluorophenyl-5-hexylpyrimidine, 11 % trans-1-p-propylphenyl-4-pentylcyclohexane, 9 % trans-1-p-ethoxyphenyl-4-propylcyclohexane, 7 % trans-1-p-butoxyphenyl-4-propylcyclohexane, 7 % 2-p-ethylphenyl-5-propylpyrimidine, 7 % 2-p-propylphenyl-5-propylpyrimidine, 5 % 2-p-pentyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-heptylpyrimidine, 7 % 1-[trans-4-(trans-propylcyclohexyl)-cyclohexyl]- 2-(p-propylphenyl)-ethane, 7 % 1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]- 2-(p-methylphenyl)-ethane, 7 % 1-[trans-4-(trans-propylcyclohexyl)-cyclohexyl]- 2-(p-pentylphenyl)-ethane and
5 % 4-nonyl-4 ' - (trans-4-pentylcyclohexyl )-biphenyl
has a clearing point of 50.9°, Δε = 0.5 and Δn = 0.121.
Example 4
A liquid crystalline phase consisting of
3 % 2-p-cyanophenyl-5-pentyl-1,3-dioxane,
10 % trans-1-p-propylphenyl-4-pentylcyclohexane, 9 % trans-1-p-ethoxyphenyl-4-propylcyclohexane, 7 % 2-p-ethylphenyl-5-propylpyrimidine, 7 % 2-p-propylphenyl-5-propylpyrimidine,
6 % 2-p-ethylphenyl-5-heptylpyrimidine,
5 % 2-p-pentyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-heptylpyrimidine,
22 % trans-4-(trans-4-propylcyclohexyl)-1-(4-ethylphenyl)-cyclohexane and
11 % trans-4-(trans-4-propylcyclohexyl)-1-4-propylphenylcyclohexane
has a clearing point of 56.5°, Δε = 1.3 and Δn = 0.132. Example 5
A liquid crystalline phase consisting of
3 % 2-p-cyanophenyl-5-pentyl-1,3-dioxane,
10 % trans-1-p-propylphenyl-4-pentylcyclohexane, 9 % trans-1-p-ethoxyphenyl-4-propylcyclohexane,
7 % 2-p-ethylphenyl-5-propylpyrimidine, 7 % 2-p-propylphenyl-5-propylpyrimidine,
6 % 2-p-(trans-4-propylcyclohexyl)-phenyl-5-heptyl- pyrimidine, 5 % 2-p-pentyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-heptylpyrimidine, 11 % 1-[trans-4-(trans-4-propylcyclohexyl-cyclohexyl]- 2-(p-methylphenyl)-ethane,
11 % 1-[trans-4-(trans-4-propylcyclohexyl-cyclohexyl]- 2-(p-propylphenyl)-ethane and. 11 % 1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]- 2-(p-pentylphenyl)-ethane
has a clearing point of 67.6°, Δε = 1.3 and Δn = 0.129.
Example 6
A liquid crystalline phase consisting of
3 % 2-p-cyanophenyl-5-pentyl-1,3-dioxane,
10 % trans-1-p-pfopylphenyl-4-pentylcyclohexane, 9 % trans-1-p-ethoxyphenyl-4-propylcyclohexane,
7 % 2-p-ethylphenyl-5-propylpyrimidine, 7 % 2-p-propylphenyl-5-propylpyrimidine, 6 % 2-p-ethylphenyl-5-heptylpyrimidine,
5 % 2-[trans-4-(trans-4-butylcyclohexyl)-cyclohexyl]- 5-propylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-hexylpyrimidine,
5 % 2-p-heptyloxyphenyl-5-heptylpyrimidine,
5 % 2-[trans-4-(trans-4-butylcyclohexyl)-cyclohexyl]- 5-heptylpyrimidine, 11 % 1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]- 2-(p-methylphenyl)-ethane,
11 % 1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]- 2-(p-propylphenyl)-ethane and
11 % 1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]- 2-(p-pentylpheny1)-ethane
has a clearing point of 62.2°, Δε = 1.3 and Δn = 0.119.
Example 7
A liquid crystalline phase consisting of
3 % 2-p-cyanophenyl-5-pentyl-1,3-dioxane, 10 % trans-1-p-propylphenyl-4-pentylcyclohexane, 9 % trans-1-p-ethoxyphenyl-4-propylcyclohexane, 7 % 2-p-ethylphenyl-5-propylpyrimidine, 7 % 2-p-propylphenyl-5-propylpyrimidine,
6 % 2-p-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl] phenyl-5-heptylpyrimidine,
5 % 2-p-pentyloxyphenyl-5-hexylpyrimidine,
5 % 2-p-heptyloxyphenyl-5-hexylpyrimidine,
5 % 2-p-nonyloxyphenyl-5-hexylpyrimidine,
5 % 2-p-heptyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-heptylpyrimidine, ll % 1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-
2-(p-methylphenyl)-ethane, 11 % 1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]- 2-(p-propylphenyl)-ethane and
11 % 1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]- 2-(p-pentylphenyl)-ethane
has a clearing point of 73.6°, Δε = 1.2 and Δn = 0.13.
Example 8
A liquid crystalline phase consisting of
3 % 2-p-cyanophenyl-5-pentyl-1,3-dioxane,
10 % trans-1-p-propylphenyl-4-pentylcyclohexane, 9 % trans-1-p-ethoxyphenyl-4-propylcyclohexane, 7 % 2-p-ethylphenyl-5-propylpyrimidine, 7 % 2-p-propylphenyl-5-propylpyrimidine, 6 % 2-p-ethylphenyl-5-heptylpyrimidine, 5 % 2-p-pentylσxyphenyl-5-hexylpyrimidme, 5 % 2-p-heptyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-hexylpyrimidine, 5 % 2-(4'-octyloxybiphenyl-4-yl)-5-heptylpyrimidine, 5 % 2-(4'-methoxybiphenyl-4-yl)-5-heptylpyrimidine,
11 % 1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]- 2-(p-methylphenyl)-ethane, 11 % 1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]- 2-(p-propylphenyl)-ethane and 11 % 1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]- 2-(p-pentylphenyl)-ethane
has a clearing point of 65.9°, Δε = 1.1 and Δn = 0.141. Example 9
A liquid crystalline phase consisting of
2 % 4-cyanophenyl p-pentylbenzoate, 11 % trans-1-p-propylphenyl-4-pentylcyclohexane, 9 % trans-1-p-ethoxyphenyl-4-propylcyclohexane, 7 % trans-1-p-butoxyphenyl-4-propylcyclohexane, 7 % 2-p-ethylphenyl-5-propylpyrimidine, 7 % 2-p-propylphenyl-5-propylpyrimidine, 5 % 2-p-pentyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-heptylpyrimidine, 9 % 1-[trans-4-(trans-propylcyclohexyl)-cyclohexyl]- 2-(p-methylphenyl)-ethane,
9 % 1-[trans-4-(trans-propylcyclohexyl)-cyclohexyl]- 2-(p-propylphenyl)-ethane, 9 % 1-[trans-4-(trans-propylcyclohexyl)-cyclohexyl]- 2-(p-pentylphenyl)-ethane and
5 % 4-nonyl-4'-(trans-4-pentylcyclohexyl)-biphenyl
has a clearing point of 59.8°, Δε = 0.7 and Δn = 0.126
Example 10
A liquid crystalline phase consisting of
2 % 2-p-trifluoromethoxyphenyl-5-heptylpyrimidine, 11 % trans-1-p-propylphenyl-4-pentylcyclohexane, 9 % trans-1-p-ethoxyphenyl-4-propylcyclohexane, 7 % trans-1-p-butoxyphenyl-4-propylcyclohexane, 7 % 2-p-ehtylphenyl-5-propylpyrimidine, 7 % 2-p-propylphenyl-5-propylpyrimidine, 5 % 2-p-pentyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-nonyloxlyphenyl-5-hexylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-heptylpyrimidine, 9 % 1-[trans-4-(trans-propylcyclohexyl)-cyclohexyl]-
2-(p-methylphenyl)-ethane, 9 % 1- [trans-4-(trans-propylcyclohexyl)-cyclohexyl]- 2-(p-propylphenyl)-ethane,
9 % 1-[trans-4-(trans-prtopylcyclohexyl)-cyclohexyl]- 2-(p-pentylphenyl)-ethane and 5 % 4-nonyl-4'-(trans-4-pentylcyclohexyl)-biphenyl
has a clearing point of 58.2°, Δε = 0.6 and Δn = 0.125.
Example 11
A liquid crystalline phase consisting of
1 % p-(trans-4-heptylcyclohexyl)-benzonitrile, 12 % trans-1-p-propylphenyl-4-pentylcyclohexane, 10 % trans-1-p-ethoxyphenyl-4-propylcyclohexane, 7 % trans-1-p-butoxyphenyl-4-propylcyclohexane, 7 % 2-p-ethylphenyl-5-propylpyrimidine, 7 % 2-p-propylphenyl-5-propylpyrimidine, 5 % 2-p-pentyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-nongloxyphenyl-5-hexylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-heptylpyrimidine, 11 % 1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl] -2-(p-propylphenyl)-ethane,
10 % 1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]' -2-(p-pentylphenyl)-ethane, and 10 % 1-[trans-4-(5-propylpyrimidin-2-yl)-cyclohexyl]- 2-(trans-4-pentylcyclohexyl)-ethane
has a clearing point of 60°, Δn = 0.12, Δε = +1.2, Δε/ε = 0.3, K3/K1 = 0.82 and Vth = 4,0 Volt.
Example 12
A liquid crystalline phase consisting of
1 % 4,-heptyl-4'-cyanobiphenyl,
5 % 2-p-ethylphenyl-5-heptylpyrimidine,
5 % 2-p-methoxyphenyl-5-hexylpyrimidine, 5 % 2-p-methoxyphenyl-5-heptylpyrimidine, 5 % 2-p-methoxyphenyl-5-nonylpyrimidine, 5 % 2-p-pentyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-hexyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-hexylpyrimidine,
5 % 2-p-heptyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-nonylpyrimidine, 5 % 2-p-hexyloxyphenyl-5-nonylpyrimidine, 11 % 1-[trans-4-(5-propylpyrimidin-2-yl)-cyclohexyl]- 2-(trans-4-pentylcyclohexyl)-ethane, 4 % p-(trans-4-propylcyclphexyl)-phenyl trans-4-(trans- 4-propylcyclohexyl)-cyclohexane carboxylate. 12 % trans-1-p-methoxyphenyl-4-propylcyclohexane, 6 % trans,trans-4-butanoyloxy-4-propylcyclohexylcyclohexane,
6 % trans,trans-4-hexanoyloxy-4-propylcyclohexylcyclohexane,
has a clearing point of 60°, Δn = 0.13, Δε = +1.2, Δε/ε = 0.3, K3/K1 = 0.7 and Vth = 4,0 Volt.
Example 13
A liquid crystalline phase consisting of
1 % 2-p-cyanophenyl-5-heptylpyrimidine, 5 % 2-p-ethylphenyl-5-heptylpyrimidine, 5 % 2-p-methoxyphenyl-5-hexylpyrimidine, 5 % 2-p-methoxyphenyl-5-heptylpyrimidine, 5 % 2-p-methoxyphenyl-5-nonylpyrimidine, 5 % 2-p-pentyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-hexyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-hexylpyrimidme, 5 % 2-p-heptyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-nonylpyrimidine, 5 % 2-p-hexyloxyphenyl-5-nonylpyrimidme,
11 % 1-[trans-4-(5-propylpyrimidin-2-yl)-cyclohexyl]- 2-(trans-4-pentylcyclohexyl)-ethane. 4 % p-(trans-4-propylcyclohexyl)-phenyl trans-4-(trans- 4-propylcyclohexyl)-cyclohexane carboxylate.
12 % trans-1-p-methoxyphenyl-4-propylcyclohexane, 6 % trans,trans-4-butanoyloxy-4-propylcyclohexylcyclohexane,
6 % trans,trans-4-hexanoyloxy-4-propylcyclohexylcyclohexane,
has a clearing point of 59°, Δn = 0.13, Δε = +1.2, Δε/ε = 0.3, K3/K1 = 0.69 and Vth = 4,0 Volt.
Example 14
A liquid crystalline phase consisting of
1 % 2-p-cyanophenyl-5-heptylpyrimidine, 12 % trans-1-p-methoxyphenyl-4-propylcyclohexane,
6 % trans,trans-4-butanoyloxy-4'-propylcyclohexyl- cyclohexane, 6 % trans,trans-4-hexanoyloxy-4'-propylcyclohexyl- cyclohexane, 5 % 2-(trans-4-ethylcyclohexyl)-5-heptylpyrimidine,
5 % 2-p-methoxyphenyl-5-hexylpyrimidine, 5 % 2-p-ρentyloxyρhenyl-5-hexylpyrimidine,
5 % 2-p-hexyloxyphenyl-5-hexylpyrimidme, 5 % 2-p-nonyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-methoxyphenyl-5-heptylpyrimidine,
5 % 2-p-heptyloxyphenyl-5-heptylpyrimidme, 5 % 2-p-nonyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-methoxyphenyl-5-nonylpyrimidine, 5 % 2-p-hexyloxyphenyl-5-nonylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-nonylpyrimidine,
5 %' 2-(trans-4-heptylcyclohexyl)-5-hexyloxypyrimidine, 5 % 2-(trans-4-heptylcyclohexyl)-5-nonyloxypyrimidine, 11 % 1-[trans-4-(5-propylpyrimidin-2-yl)-cyclohexyl]- 2-(trans-4-pentylcyclohexyl)-ethane 4 % p-(trans-4-propylcyclohexyl)-phenyl trans-4-(trans- 4-propylcyclohexyl)-cyclohexane carboxylate
has a clearing point of 56°, Δn = 0.12, Δε = +1.2, Δε/ε = 0.3, K3/K1 = 0.74 and Vth = 4,2 Volt.
Example 15
A liquid crystalline phase consisting of
1 % 2-p-cyanophenyl-5-heptylpyrimidine, 12 % trans-1-p-methoxyphenyl-4-propylcyclohexane,
3 % 4-methoxy-4'-propylbiphenyl,
4 % trans-4-propylcyclohexyl trans-4-pentylcyclohexane carboxylate,
5 % trans-4-pentylcyclohexyl trans-4-pentylcyclohexane carboxylate,
4 % trans,trans-4-hexanoyloxy-4'propylpyclohecylcyclo- hexane,
5 % 2-p-ethylphenyl-5-heptylpyrimidine,
5 % 2-p-heptyloxyphenyl-5-hexylpyrimidme , 5 % 2-p-pentyloxyphenyl-5-hexylpyrimidine ,
5 % 2-p-hexyloxyphenyl-5-hexylpyrimidme, 5 % 2-p-nonyloxyphenyl-5-hexylpyrimidine , 5 % 2-p-methoxyphenyl-5-heptylpyrimidme, 5 % 2-p-heptyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-heptylpyrimidine ,
5 % 2-p-methoxyphenyl-5-nonylpyrimidine , 5 % 2-p-hexyloxyphenyl-5-nonylpyrimidine , 5 % 2-p-nonyloxyphenyl-5-nonylpyrimidine,
10 % 1-[trans-4-pentylcyclohexyl)-2-(4'-ethyl-2'-fluorobiphenyl-4-yl)-ethane and
6 % p-(trans-4-propylcyclohexyl)-phenyl trans-4-(trans- 4-propylcyclohexyl)-cyclohexane carboxylate
has a clearing point of 59°, Δn = 0.13, Δε = 0.7, Δε/ε = 0.2, K3/K1 = 0.72 and Vth = 4,8 Volt.
Example 16
A liquid crystalline phase consisting of
1 % 2-p-cyanophenyl-5-heptylpyrimidine., 12 % trans-1-p-methoxyphenyl-4-propylcyclohexane,
3 % 4-methoxy-4'-propylbiphenyl,
4 % trans, trans-4-hexanoyloxy-4'-propylcyclohexyl- cyclohexane,
4 % trans-4-propylcyclohexyl trans-4-pentylcyclo- hexanecarboxylate,
5 % trans-4-pentylcyclohexyl trans-4-pentylcyclo- hexanecarboxylate, 5 % 2-(trans-4-ethylcyclohexyl)-5-heptylpyrimidine, 5 % 2-p-pentyloxy phenyl-5-hexylpyrimidine, 5 % 2-p-hexyloxy phenyl-5-hexylpyrimidine, 5 % 2-p-nonyloxy phenyl-5-hexylpyrimidine, 5 % 2-p-methoxy phenyl-5-heptylpyrimidine, 5 % 2-p-heptyloxy phenyl-5-heptylpyrimidine, 5 % 2-p-methoxy phenyl-5-nonylpyrimidine, , 5 % 2-p-hexyloxy phenyl-5-nonylpyrimidine, 5 % 2-p-nonyloxy phenyl-5-nonylpyrimidine,
5 % 2-(trans-4-heptylcyclohexyl)-5-hexyloxypyrimidine,
5 % 2-(trans-4-heptylcyclohexyl)-5-nonyloxypyrimidine, 10 % 1-[trans-4-pentylcyclohexyl)-2-(4'-ethyl-2'-fluorobiphenyl-4-yl)-ethane and
6 % p-(trans-4-propylcyclohexyl)-phenyl trans-4-(trans-
4-propylcyclohexyl)-cyclohexane carboxylate
has a clearing point of 56°, Δn = 0.12, Δε = +0.7, Δε/ε = 0.2, K3/K1 = 0.77 and Vth = 5,0 Volt.
Example 17
A liquid crystalline phase consisting of
1 % 2-(3-fluoro-4-cyanophenyl)-5-heptylpyrimidine, 12 % trans-1-p-methoxyphenyl-4-propylcyclohexane, 7 % trans,trans-4-hexanoyloxy-4'-propylcyclohexyl- cyclohexane, 5 % trans-4-propylcyclohexyl trans-4-pentyl cyclohexane carboxylate, 5 % trans-4-pentylcyclohexyl trans-4-pentyl cyclohexane carboxylate,
5 % 2-p-propylphenyl-5-pentylpyrimidine, 5 % 2-p-ethylphenyl-5-heptylpyrimidine, 5 % 2-p-heptyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-hexyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-methoxyphenyl-5-heptylpyrimidine, 5 % 2-p-hepJtyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-methoxyphenyl-5-nonylpyrimidine, 5 % 2-p-hexyloxyphenyl-5-nonylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-nonylpyrimidine, 10 % 1- [trans-4-(5-propylpyrimidin-2-yl)-cyclohexyl]- 2-(trans-4-pentylcyclohexyl)-ethane 5 % p-(trans-4-propylcyclohexyl)-phenyl trans-4-(trans- 4-propylcyclohexyl)-cyclohexane carboxylate
has a clearing point of 60°, Δn = 0.12, Δε = +1.2, Δε/ε = 0.3, K3/K1 = 0.75 and Vth = 4,1 Volt.
Example 18
A liquid crystalline phase consisting of
1 % 2-(3-fluoro-4-cyanophenyl)-5-heptylpyrimidine, 12 % trans-1-p-methoxyphenyl-4-propylcyclohexane, 7 % trans,trans-4-hexanoyloxy-4'-propylcyclohexyl- cyclohexane, 5 % trans-4-propylcyclohexyl trans-4-pentyl cyclohexane carboxylate, 5 % trans-4-pentylcyclohexyl trans-4-pentyl cyclohexane carboxylate,
5 % 2-(trans-4-ethylcyclohexyl)-5-heptylpyrimidine, 5 % 2-(trans-4-propylcyclohexyl)-5-pentylpyrimidine, 5 % 2-p-hexyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-hexylpyrimidine, 5 % 2-p-methoxyphenyl-5-heptylpyrimidine,
5 % 2-p-heptyloxyphenyl-5-heptylpyrimidine, 5 % 2-p-methoxyphenyi-5-nonylpyrimidine, 5 % 2-p-hexyloxyphenyl-5-nonylpyrimidine, 5 % 2-p-nonyloxyphenyl-5-nonylpyrimidine, 5 % 2(trans-4-heptylcyclohexyl)-5-hexyloxypyrimidine, 5 % 2 (trans-4-heptylcyclohexyl)-5-nonyloxypyrimidine, 10 % 1-[trans-4-(5-propylpyrimidin-2-yl)-cyclohexyl]- 2-(trans-4-pentylcyclohexyl)-ethane 5 % p-(trans-4-propylcyclohexyl)-phenyl trans-4-(trans- 4-propylcyclohexyl)-cyclohexane carboxylate
has a clearing point of 56°, Δn = 0.11, Δε = +1.1, Δε/ε = 0.3, K3/K1 = 0.81 and Vth = 4,3 Volt.

Claims

Patent Claims:
1. In a twisted nematic liquid crystal display device operating in the high multiplex mode, having a high contrast and containing a liquid crystal mixture which has a ratio of the elastic constants K3/K1 as small as possible but not more than 0.9 and a ratio of Δε/ε of at most +0.3 and comprises at least three liquid crystal materials:
(a) at least 10 wt% of a first liquid crystal material comprising at least one of liquid crystal compounds represented by general formula:
wherein R, represents a group R or OR; and R2 represents R or OR; R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- and/or -CH=CH-, two oxygen atoms not being directly attached to one another, A is 1,4- phenylene or trans-1,4-cyclohexylene, Z1 is
-CO-O-, -O-CO-, -CH2-O-, -OCH2-, -CH2CH2- or a single bond,
Q1 is 1,4-phenylene or trans-1,4-cyclohexylene, and m is 0, 1 or 2, (b) less than 10 wt% of a second liquid crystal material comprising one or more liquid crystal compounds having a distinct positive dielectric anis-otropy (Δε ≧ + 3 ); and,
(c) less than 90 wt% of a third liquid crystal material comprising at least one liquid crystal compound having a negative or substantially 0 dielectric anisotropy,
the improvement wherein
(1) the first liquid crystal material comprises at least one of liquid crystal compounds represented by general formulae lb to li:
wherein R1 represents a group R or OR; and R2 represents R or OR; R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non- adjacent CH2 groups may be replaced by -O- and/or -CH=CH-, two oxygen atoms not being directly attached to one another,
and/or
(2) the third liquid crystal material comprises at least one liquid crystal compound represented by the general formulae Illd to Illh, III6 to III15 and/or III16 and III17:
wherein R 11, R13, R15 and R18 each independently represent R, and R9, R10, R12, R14, R16 and R 17 each independently represent R or OR,
R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another and A 4 is 1,4-cyclohexenylen,
wherein R29, R31, R33, R35, R37, R39, R40,
R.41, R43, R.45, R46, R47, and. R48 each independently represent R, R30, R32, R34, R36, R38, R 42 and R44 each independently represent R or
OR; R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another, and A4 is 1,4-cyclohexenylen,
wherein R49, R50, R51 and, R52 each represent.
R, R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another.
2. An improved liquid crystal mixture according to claim 1 in a device, operating in the first Gooch and Tarry transmission minimum.
3. An improved liquid crystal mixture according to claim 2 in a device, wherein the electro-optical characteristic curve is at least as steep as that curve in the second such transmission minimum.
4. An improved liquid crystal mixture according to claim 3 in a device, wherein the steepness of the characteristic curve in the first minimum is greater than that in the second minimum.
5. An improved liquid crystal mixture according to claim 1 in a device, wherein K3/K1 is 0.4 to 0. and Δε/ε is 0.4 to 0.3
6. An improved liquid crystal mixture according to claim 1 in a device, wherein K3/K1 is 0.2 to 0.75 and Δε/ε I is 0.1 to 0.3
7. An improved liquid crystal mixture according to claim 1, wherein the liquid crystal mixture comprises at least five components.
8. An improved liquid crystal mixture according to claim 1, wherein the first liquid crystal material comprises at least one of liquid crystal compounds represented by the general formula la
9. An improved liquid crystal mixture according to claim 1, wherein the second liquid crystal material comprises at least one of liquid crystal compounds represented by the general formulae Ila to lId:
X being hydrogen or fluorine, Y being cyano, trifluoromethoxy or fluorine, r being 0 or 1 and R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another.
10. An improved liquid crystal mixture according to claim 1, wherein the third liquid crystal material comprises liquid crystal compounds having a dielectric anisotropy of -1 to +1.
11. An improved liquid crystal mixture according to claim 1, wherein the third liquid crystal material comprises at least one of liquid crystal compounds represented by the general formulae IlIa to IIIc;
wherein R 3 represents R; and R4 represents R or OR
wherein R5 represents R; and R6 represents R or OR
wherein R 7 represents R; and R8 represents R or OR; R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another.
12. An improved liquid crystal mixture according to claim 1, wherein the third liquid crystal material further comprises at least one of liquid crystal compounds represented by general formulae:
wherein R 19 and R20 represent independently from one another R
wherein R 21 and R22 represent mdenpendently from one another R;
wherein R 23 and R24 represent independently from one another R;
wherein R25 and R26 represent independently from one another R;
wherein R 27 and R28 represent independently from one another R; and n is 0 or 1;
R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another.
13. An improved liquid crystal mixture according to claim 1, wherein the formulation ratios of said first liquid crystal material, said second liquid crystal material and said third liquid crystal material are at least 30 wt%, less than 10 wt% and less than 70 wt%, respectively.
14. An improved liquid crystal mixture according to claim 8, wherein the formulation ratios of said first liquid crystal material, said second liquid crystal material and said third liquid crystal material are 30 to 65 wt%, less than 5 wt% and 35 to 70 wt%, respectively.
15. A method of simultaneously minimizing the dependence of contrast on the angle of observation of an- electrooptical display element based on a liquid crystal mixture and of maximizing its multiplexing capacity by maximizing its steepness of its character- istic curve, comprising operating the element in the first Gooch and Tarry transmission minimum, selecting a mixture having a K3/K1 ratio as small as possible but not more than 0.9 and a ratio of Δε/ε _ of at most 0.3, said mixture comprises at least three liquid crystal materials:
(a) at least 10 wt% of a first liquid crystal material comprising at least one of liquid crystal compounds represented by general formula:
wherein R1 represents a group R or OR; and R2 represents R or OR; R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non- adjacent CH2 groups may be replaced by -O- and/or -CH=CH-, two oxygen atoms not being directly attached to one another, A is 1,4- phenylene or trans-1,4-cyclohexylene, Z is -CO-O-, -O-CO-, -CH2-O-, -OCH2-, -CH2CH2- or a single bond, Q1 is 1,4-phenylene or trans-1,4-cyclohexylene, and m is 0, 1 or 2,
(b) less than 10 wt% of a second liquid crystal material comprising one or more liquid crystal compounds having a distinct positive dielectric anisotropy (Δε ≧ + 3); and, (c) less than 90 wt% of a third liquid crystal material comprising at least one liquid crystal compound having a negative or substantially 0 dielectric anisotropy,
and
(1) the first liquid crystal material comprises at least one of liquid crystal compounds represented by general formulae lb to li:
wherein R1, represents a group R or OR; and R2 represents R or OR; R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- and/or -CH=CH-, two oxygen atoms not being directly attached to one another,
and/or (2) the third liquid crystal material comprises at least one of liquid crystal compound represented by the general formulae Illd to Illh, Ill6 to Ill15 and/or Ill16 and Ill17:
wherein R 11, R13, R15 and R18 each independently represent R, and R9, R10, R12, R14, R16 and R 17 each independently represent R or OR,
R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent OBL groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another and A4 is 1,4-cyclohexenylen, wherein R29, R31, R33, R35, R37, R39, R40, R41, R43, R45, R46, R47, and R48 each independently represent R, R30, R32, R34, R36, R38, R 42 and R44 each independently represent R or OR, R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent
CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another, and A4 is 1,4-cyclohexenylen,
wherein R 49, R50, R51 and R52 each represent R, R being in each case independently a straight chain alkyl group having up to 12 carbon atoms wherein one or two non-adjacent CH2 groups may be replaced by -O- or -CH=CH-, two oxygen atoms not being directly attached to one another.
EP89901058A 1988-01-12 1989-01-04 Improved liquid crystal mixture Withdrawn EP0354940A1 (en)

Applications Claiming Priority (2)

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EP88100274 1988-01-12
DE8810027U 1988-01-12

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Publication number Priority date Publication date Assignee Title
DE4107167B4 (en) * 1991-03-06 2008-05-08 Merck Patent Gmbh liquid crystal mixture
WO1996034071A1 (en) * 1995-04-25 1996-10-31 Chisso Corporation Liquid crystal composition and liquid crystal display element
US7563492B2 (en) * 2005-11-16 2009-07-21 Chisso Corporation Liquid crystal composition and liquid crystal display device

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DE3404117A1 (en) * 1984-02-07 1985-08-08 Merck Patent Gmbh, 6100 Darmstadt LIQUID CRYSTALLINE PHASE
DE3433248A1 (en) * 1984-09-11 1986-03-20 Merck Patent Gmbh, 6100 Darmstadt ELECTROOPTICAL DISPLAY ELEMENT
DE3609141A1 (en) * 1986-03-19 1987-09-24 Merck Patent Gmbh ELECTROOPTICAL DISPLAY ELEMENT

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WO1989006677A1 (en) 1989-07-27
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