EP3408350A1

EP3408350A1 - Liquid-crystalline medium

Info

Publication number: EP3408350A1
Application number: EP16820168.9A
Authority: EP
Inventors: Michael Wittek; Dagmar Klass
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2016-01-25
Filing date: 2016-12-30
Publication date: 2018-12-05
Also published as: US20190031957A1; WO2017129216A1; TW201736580A; JP2019510838A; CN108603117A; KR20180102164A; DE102016015630A1

Abstract

The invention relates to a liquid-crystalline medium comprising one or more compounds of formula BO, wherein the parameters have the meaning indicated in claim 1. The invention also relates to the use of the liquid-crystalline medium for electro-optical purposes, in particular in liquid crystal light valves for lighting devices for motor vehicles, to liquid crystal light valves containing said medium, and to lighting devices for motor vehicles, comprising liquid crystal light valves of said type, and to compounds of formula BO.

Description

Liquid crystalline medium

The present invention relates to a liquid-crystalline medium containing bicyclooctane derivatives, the use thereof for electro-optical purposes, in particular for liquid-crystal light valves for use in

Automotive lighting devices, liquid crystal light valves incorporating said medium, and lighting devices based on such liquid crystal light valves, and bicyclooctane derivatives contained in said media. Liquid crystals are mainly used as dielectrics in display devices, since the optical properties of such substances can be influenced by an applied voltage. electro-optical

Devices based on liquid crystals are known to the person skilled in the art and can be based on various effects. Such devices are for example TN cells with twisted nematic structure or STN cells ("super-twisted nematic"). Modern TN and STN displays are based on an active matrix of individually addressable liquid crystal light valves (the pixels) with integrated red, green and blue color filters for additive generation of the color images.

The exploited in liquid crystal displays electro-optical effects are also used in recent times for other applications.

In DE 19910004 A1 LCD screens are described as a panel for arbitrary embodiment of the brightness distribution of lighting devices for motor vehicles, whereby the brightness distribution should be flexibly adapted to the driving situation.

Such adaptive lighting devices for motor vehicles

(Adaptive front lighting system, AFS) produce a adapted to the particular situation and the environmental conditions headlights and are able to react, for example, the light and weather conditions, the vehicle movement or the presence of other road users to the environment and constant optimally illuminate and not disturb other road users. In US 4,985,816 For example, disclosed components in which a spatial

Light modulator in the form of a liquid crystal (LCD) display panel consisting of a grid of translucent elements, analogous to the pixels of a liquid crystal display, an electrically switchable, complete or partial shading of the cone of light generated with the aim of dazzle the driver of oncoming vehicles not or less. Such spatial light modulators are referred to as liquid crystal light valves as already mentioned. Because of the similar functioning as with projectors one speaks also of

Vehicle lights of the projector type. The image information for the controlled shading of the light cone preferably delivers a digital camera.

A liquid crystal light valve according to the present invention may comprise a single area for modulating the light or a grid (matrix) of a plurality of identical or different sub-areas

Thus, a grid of liquid crystal light valves is or may be considered as a special case of a monochrome matrix liquid crystal display as a part of a liquid crystal display.

An illumination device in the sense of the invention is in particular an AFS or part of an AFS. A lighting device according to the invention is used in particular for illuminating an area in front of a vehicle or motor vehicle. Motor vehicle in the sense of the invention is in particular a land vehicle which can be used individually in road traffic. Motor vehicles within the meaning of the invention are in particular not on land vehicles

Internal combustion engine limited. in the above-mentioned US 4,985,816

Liquid crystal light valve is a TN cell as optical

Used modulation element which represents picture elements corresponding to the desired brightness profile of the vehicle lighting, for example, a driving voltage to the TN liquid crystal for modulating (control) the transmittance of a picture element is created. Because of the polarizers required there, only about half of the light from the light source can be used. A likewise based on a TN cell alternative, which makes it possible to harness more than half of the light of the light source of the illumination device is disclosed in DE 10 2013 113 807 A1. Therein, the light by means of a polarizing beam splitter into two partial beams with each other

divided perpendicular plane of polarization and directed by two separate, separately switchable liquid crystal elements.

Such lighting devices are characterized by comparatively high operating temperatures of typically 60-80 ° C, which makes special demands on the liquid crystal media used: the clearing points must be higher than 120 ° C, preferably higher than 140 ° C and because of the strong light exposure, these media have a particularly high light stability. This may u.U. For example, be favored by using materials with the least possible birefringence. The liquid crystal materials must also have good chemical and thermal stability and good electrical field stability. Furthermore, the liquid crystal materials should have low viscosity and give relatively short response times, lowest possible operating voltages and high contrast in the cells.

Furthermore, they should be stored at normal operating temperatures, i. have a suitable mesophase in the broadest possible range below and above room temperature, for example for the above

Cells a nematic or cholesteric mesophase, preferably from -40 ° C to 150 ° C. Since liquid crystals are usually used as mixtures of several components, it is important that the

Components are readily miscible with each other. Other properties, such as electrical conductivity, dielectric anisotropy and optical anisotropy, have different requirements depending on the cell type and field of application

suffice. For example, materials for cells of twisted nematic structure should have positive dielectric anisotropy and low electrical conductivity. For example, for light valves in matrix liquid crystal displays with integrated non-linear elements for switching individual pixels (MFK displays), media with high positive dielectric anisotropy, broad nematic phases, relatively low birefringence, very high resistivity, good light and temperature stability and less Steam pressure desired. Such matrix liquid crystal displays are known and the design principle can also be used for the lighting device according to the invention. As non-linear elements for individual switching of the individual

For example, pixels may be used for active elements (i.e., transistors). One speaks then of an "active matrix", whereby one can distinguish two types: 1. MOS (Metal Oxide Semiconductor) or other diodes on silicon wafer as substrate.

2. Thin-film transistors (TFT) on a glass plate as a substrate. The use of monocrystalline silicon as a substrate material limits the display size, since the modular composition of various partial displays on the joints leads to problems.

In the more promising Type 2, which is preferred, the TN effect is usually used as the electro-optic effect. A distinction is made between two technologies: TFTs made of compound semiconductors, such as e.g. CdSe or TFTs based on polycrystalline or amorphous silicon. The latter technology is being worked on worldwide with great intensity. The TFT matrix is applied on the inside of one glass plate of the display, while the other glass plate on the inside carries the transparent counter electrode. Compared to the size of the

Pixel electrode, the TFT is very small and does not disturb the picture practically. The TFT displays and corresponding light valves for

Illuminators usually operate as TN cells with crossed polarizers in transmission and are backlit.

The term MFK displays here includes any matrix display with integrated nonlinear elements, i. In addition to the active matrix also displays with passive elements such as varistors or diodes (MIM = metal-insulator-metal).

In addition to problems in terms of the angular dependence of the contrast and the switching times resulting in MFK displays difficulties due to not sufficiently high resistivity

Liquid crystal mixtures [TOGASHI, S., SEKOGUCHI, K., TANABE, H., YAMAMOTO, E., SORIMACHI, K., TAJIMA, E., WATANABE, H.,

SHIMIZU, H., Proc. Eurodisplay 84, Sept. 1984: A 210-288 Matrix LCD Controlled by Double Stage Diode Rings, p. 141 ff, Paris; STROMER, M., Proc. Eurodisplay 84, Sept. 1984: Design of Thin Film Transistors for Matrix Addressing of Liquid Crystal Displays, p. 145 ff, Paris]. As the resistance decreases, the contrast of a MFK display deteriorates and the problem of "after image elimination" may occur. As the resistivity of the liquid crystal mixture by

Interaction with the internal surfaces of the display generally decreases over the life of a MFK display, high (initial) resistance is very important to obtain acceptable service lives.

In particular, in low-volt mixtures, it has not been possible to realize very high resistivities. Furthermore, it is important that the resistivity shows the smallest possible increase with increasing temperature and after temperature and / or light exposure. This is also the case when using light valves in

Lighting equipment for motor vehicles relevant because of

Liquid crystal therein extreme temperature and light loads

low initial resistivity and a rapid increase in resistivity under load is usually correlated with low long-term stability. Also particularly disadvantageous are the low-temperature properties of the mixtures of the prior art. It is required that no crystallization and / or smectic phases occur even at low temperatures and that the temperature dependence of the viscosity is as low as possible. The MFK displays of the prior art thus do not meet the requirements for use in lighting equipment.

There is thus still a great need for

Liquid crystal mixtures with very high resistivity at the same time large working temperature range and high light stability.

For liquid crystal light valves for lighting equipment for

Vehicles are desired media that allow the following advantages in the cells: extended nematic phase range (especially at high temperatures)

stable on storage, even at low temperatures

Switchability at low temperatures

increased resistance to light.

With the media available from the prior art, it is not possible to realize these advantages while maintaining the other parameters. For example, liquid-crystal media of the laid-open specification DE 102 23 061 A1 and DE 10 2008 062858 A1 have a low Δη, but the clearing points are around 80 ° C. in a range which is too low for the application according to the invention.

The invention has for its object to provide media, especially for the above-mentioned liquid crystal light valves for lighting devices for motor vehicles, which do not have the disadvantages mentioned above or only to a lesser extent, and preferably at the same time very high clearing points and low birefringence.

It has now been found that this object can be achieved if used in liquid crystal components according to the invention media. The invention thus relates to a liquid-crystalline medium based on a mixture of polar compounds, characterized

characterized in that it contains one or more compounds of the formula BO

contains, in which the individual radicals have the following meanings:

_R 01 is an alkyl or alkoxy radical having 1 to 15 C atoms, where in these radicals one or more H atoms may be replaced by F, Cl, or CN and also one or more CH 2 groups each independently

-Cr ^■ - ^ - '-o · -O ^ - CC-. -o-, -co-

O- or -O-CO- can be replaced so that O atoms are not directly linked to one another, an alkyl or alkoxy radical having 1 to 15 C atoms, wherein in these radicals one or more H atoms by Cl or CN can be replaced and one or more Ch groups each independently by A_.

~ ~ _{■ '} ~ <X ^. -C = C-, -CH = CH-, -O-, -CO-O- or -O-CO- may be replaced so that O atoms are not directly linked to one another, independently of one another, 1,4-cyclohexanediyl, in which one or two CH 2 groups can be replaced by O such that O atoms are not linked to one another,

-CH2CH2-, -CF2CF2-, -C (O) O-, -OC (O) -, frans-CH = CH-, frans-CF = CF-, -CH2O-, -OCH2-, or a single bond, preferred -CH 2 CH 2 -, or a single bond, and more preferably a single bond

Y is F, Cl, CF3, or alkyl or alkoxy having 1 to 6 C atoms, in which one or more H atoms may be replaced by F, r is 0 or 1, and s is 0, 1, 2, 3 or 4.

Bicyclooctane derivatives for use in liquid-crystal mixtures are known in principle to the person skilled in the art and are described, for example, in US Pat

WO 98/13326. The compounds described therein contain unsaturated alkoxy or ester linkaged unsaturated alkenyl side chains linked to a cyclohexane ring and are therefore unsuitable for use in the present invention. The compounds of the formula BO have hitherto not been described in the prior art and, in addition to excellent thermal and UV stability, exhibit broad nematic phases, very good solubility and outstanding properties

Low-temperature stability.

The invention thus also relates to compounds of the formula BO and to processes for their preparation.

In the present application, all atoms also include their isotopes. In particular, one or more hydrogen atoms (H) may be replaced by deuterium (D), which is particularly preferred in some embodiments; a high degree of deuteration allows or facilitates the analytical detection of compounds, especially in the case of low concentrations.

If R ⁰¹ and / or R ^{02 is} an alkyl radical or an alkoxy radical, this may be straight-chain or branched. Preferably, it is straight-chain, has 2, 3, 4, 5, 6 or 7 carbon atoms and thus preferably ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy or heptoxy, furthermore methyl , Octyl, nonyl, decyl, Undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octoxy, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy or tetradecoxy.

Oxaalkyl is preferably straight-chain 2-oxapropyl (=

Methoxymethyl), 2 - (= ethoxymethyl) or 3-oxybutyl (= 2-methoxyethyl),

2-, 3- or 4-oxypentyl, 2-, 3-, 4- or 5-oxyhexyl, 2-, 3-, 4-, 5- or 6- oxyheptyl, 2-, 3-, 4-, 5- , 6-, or 7-Oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8 - or 9-oxadexyl.

If R ^{02 is} an alkyl radical in which a CH 2 group is replaced by

-CH = CH- is replaced, it may be straight-chain or branched.

It is preferably straight-chain and has 2 to 10 C atoms. It therefore means especially vinyl, prop-1, or prop-2-enyl, but-1, 2 or but-

3- enyl, pent-1-, 2-, 3- or pent-4-enyl, hex-1-, 2-, 3-, 4- or hex-5-enyl, hept-1, 2-, 3 -, 4-, 5- or hept-6-enyl, Oct-1, 2-, 3-, 4-, 5-, 6- or Oct-7-enyl, Non-1-, 2-, 3- , 4-, 5-, 6-, 7- or Νοη-8-enyl, Dec-1, 2-, 3-, 4-, 5-, 6-, 7-, 8- or Dec-9-enyl ,

If R ⁰¹ and / or R ^{02 is} an alkyl radical in which one CH 2 group has been replaced by -O- and one by -CO-, these are preferably adjacent. Thus, they include an acyloxy group -CO-O- or an oxycarbonyl group -O-CO-. Preferably, these are straight-chain and have 2 to 6 carbon atoms. They therefore particularly mean acetyloxy, propionyloxy, butyryloxy, pentanoyloxy, hexanoyloxy, acetyloxymethyl, propionyloxymethyl, butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl, 2-propionyloxyethyl, 2-butyryloxyethyl, 2-acetyloxypropyl, 3-propionyl-oxypropyl, 4-acetyl-oxybutyl, methoxycarbonyl,

Ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, propoxycarbonylmethyl, butoxycarbonylmethyl, 2- (methoxycarbonyl) ethyl, 2- (ethoxycarbonyl) ethyl, 2- (propoxycarbonyl) -ethyl, 3- (methoxycarbonyl) -propyl, 3 (Ethoxycarbonyl) -propyl or 4- (methoxycarbonyl) -butyl.

If R ^{02 is} an alkyl radical in which a CH 2 group is replaced by

-CH = CH- and an adjacent CH2 group is replaced by CO or CO-O or O-CO, this may be straight-chain or branched. It is preferably straight-chain and has 4 to 12 C atoms. It therefore particularly denotes acryloyloxymethyl, 2-acryloyl-oxyethyl, 3-acryloyloxypropyl, 4-acryloyloxybutyl, 5-acryloyloxypentyl, 6-acryloyloxyhexyl, 7-acryloyloxyheptyl, 8-acryloyloxyoctyl, 9-acryloyl-oxynonyl, 10-acryloyloxydecyl, methacryloyloxymethyl, 2 Methacryloyl oxyethyl, 3-methacryloyloxypropyl, 4-methacryloyloxybutyl, 5-methacrylooxypentyl, 6-methacryloyloxyhexyl, 7-methacryloyloxyheptyl, 8-methacryloyloxyoctyl, 9-methacryloyloxynonyl.

If R ⁰¹ and / or R ^{02 is} an alkyl or alkenyl radical which is monosubstituted by CN or CF 3, this radical is preferred

straight-chain. The substitution by CN or CF3 is in any position.

If R ^{01 is} an alkyl or alkenyl radical which is at least monosubstituted by F and / or Cl, this radical is preferably

straight-chain. For multiple substitution, the substituent is preferably F. The resulting radicals also include perfluorinated radicals. For single substitution, the fluoro or chloro substituent may be in any position, but preferably in the ω position. If R ^{02 is} an alkyl or alkenyl radical which is at least monosubstituted by Cl, this radical is preferably straight-chain. For multiple substitution, the substituent is preferably Cl. at

Single substitution, the chlorine substituent may be in any position, but preferably in the ω position.

Compounds with branched wing groups R ⁰¹ and / or R ⁰² may occasionally, for better solubility in the usual

Liquid-crystalline base materials are important, but especially as chiral dopants, if they are optically active. smectic

Compounds of this type are useful as components for ferroelectric materials.

Branched groups of this type usually contain no more than one chain branch. Preferably branched radicals R are isopropyl, 2-butyl (= 1-methylpropyl), isobutyl (= 2-methylpropyl), 2-methylbutyl, isopentyl (= 3-methylbutyl), 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, isopropoxy, 2-methylpropoxy, 2-methylbutoxy, 3-methylbutoxy, 2-methylpentoxy, 3-methylpentoxy, 2-ethylhexoxy , 1-methylhexoxy, 1-methylheptoxy. If R ⁰¹ and / or R ^{02 represents} an alkyl radical in which two or more

CH 2 groups are replaced by -O- and / or -CO-O-, it may be straight-chain or branched. Preferably, it is branched and has 3 to 12 carbon atoms. It therefore particularly denotes bis-carboxy-methyl, 2,2-bis-carboxy-ethyl, 3,3-bis-carboxy-propyl, 4,4-bis-carboxy-butyl, 5,5-biscarboxypentyl, 6,6-bis-carboxy-hexyl, 7,7-bis-carboxy-heptyl, 8,8-bis-carboxy-octyl, 9,9-bis-carboxy-nonyl, 10,10-bis-carboxy-decyl, Bis (methoxy-carbonyl) -methyl, 2,2-bis (methoxycarbonyl) -ethyl, 3,3-bis (methoxycarbonyl) -propyl, 4,4-bis (methoxycarbonyl) -butyl, 5, 5-bis (methoxycarbonyl) pentyl, 6,6-bis (methocycarbonyl) hexyl, 7,7-bis (methoxycarbonyl) heptyl, 8,8-bis (methoxycarbonyl) octyl, Bis (ethoxycarbonyl) methyl, 2,2-bis (ethoxycarbonyl) ethyl, 3,3-bis (ethoxycarbonyl) propyl, 4,4-bis (ethoxycarbonyl) butyl, 5,5-bis (ethoxycarbonyl) -hexyl. Formula BO preferably comprises compounds in which R ⁰¹ and R ^{02 are} alkyl having 2 to 5 C atoms, particularly preferably n-propyl, n-butyl or n-pentyl.

The compounds of the formula BO are preferably selected from the subformulae BO-1 and BO-2

BO-2 wherein the parameters have the meaning given above and preferably YF, Z ^{1 is} a single bond and s is 0, 1 or 2.

Particularly preferred compounds of the formulas BO-1 and BO-2 are the sub-formulas listed below:

35 wherein R ⁰¹ and R ^{02 have} the abovementioned meaning.

The compounds of the formula BO are known per se

Methods are described, as described in the literature (eg in the standard works such as Houben-Weyl, Methods of Organic Chemistry, Georg Thieme Verlag, Stuttgart), under reaction conditions that are known and suitable for the above reactions , One can also make use of known per se, not mentioned here variants.

A preferred method for preparing the compounds of the formula BO is shown in Scheme 1 below and is carried out either by Friedel-Crafts alkylation of aromatics according to GWGray, S. Kelly, Journal of the Chemical Society, Perkin Transactions 2: Physical Organic

Chemistry (1972-1999), (1), 26-31; 1981 with bicyclooctyl bromides (2) or according to a method described in EP 1887069 by reacting a bicycloctyl cation formed in situ by acid treatment of the bicyclooctanol (3) with aryl compounds.

BO

Scheme 1.

In a preferred embodiment, the media according to the invention contain

a) one or more compounds of the formula I.

and optionally b) one or more compounds of the formula II

wherein

R and R ^{2 are} an alkyl or alkoxy radical having 1 to 15 C atoms, wherein in these radicals one or more H atoms may be replaced by F and also one or more Chb groups each independently

- -, -C = C-, -CH = CH-, -O-, -CO-O- or -O-CO- can be replaced so that O atoms are not directly linked, the same or different at every occurrence

or preferred

L ² and L ²² independently of one another are H or F, preferably

L ¹ and / or L ²¹ F,

X ¹ and X ² F, Cl, CN, halogenated alkyl radical, halogenated

Alkenyl radical, halogenated alkoxy radical or halogenated alkenyloxy radical having up to 6 C atoms,

-CH ₂ CH ₂ -, -CF ₂ CF ₂ -, -COO-, trans-CH = C -,

trans-CF = CF-, -CH2O- or a single bond, preferred

-CH 2 CH 2 -, or a single bond and more preferably mean a single bond.

wherein the parameters have the meaning given under formula I and L ¹³ and L ¹⁴ independently of one another are H or F and preferably n-alkyl with up to 7 C atoms,

X ¹ F, Cl, halogenated alkyl or halogenated alkoxy having up to 6 C atoms,

L ¹ to L ^{4 are} each independently H or F, mean.

X ¹ is particularly preferably F, Cl, CF 3, OCF 3, or OCHF 2.

In a particularly preferred embodiment, the compounds of the formula I are selected from the compounds of the formulas 1-1 a to 1-1 d

wherein R ^{1 is} n-alkyl having 1 to 7 carbon atoms.

Most preferably, the medium contains at least one

Compound of the formula 1-1 b. In a further preferred embodiment, the media according to the invention comprise one or more compounds selected from the group of the compounds of the formulas IA and IB,

wherein L ¹³ and L ^{14 are} independently H or F and the other parameters have the meaning given under formula I and preferably

R ¹ n-alkyl with up to 7 C atoms,

X ¹ F, Cl, halogenated alkyl or halogenated alkoxy having up to 6 C atoms,

L ¹¹ to L ^{14 are} each independently H or F, mean.

X ¹ is particularly preferably F, Cl, CF 3, OCF 3 or OCHF 2. The compounds of the formula IA are preferably selected from the following sub-formulas IA-1 to IA-7, particularly preferably from the compounds of the formula IA-1.

where the parameters have the meaning given above.

The compounds of the formula IA are particularly preferably selected from the compounds of the formulas IA-1a to IA-1d

wherein R ^{1 has} the meaning indicated above and X ^{1 is} preferably F or OCF 3. Very particular preference is given to the compounds of the formula IA-1d.

Particularly preferred compounds of the formula IB are selected from

wherein the parameters have the abovementioned meaning and preferably at least one of the radicals L ¹¹ and L ^{12 is} F and X ^{1 is} F, Cl, CF 3 or OCF 3.

The compounds of the formula II are preferably selected from the compounds of the sub-formulas 11-1 to 11-14.

wherein the parameters have the meaning given under formula II and preferred

R ² n-alkyl having up to 7 C atoms, X ² F, Cl, halogenated alkyl or halogenated alkoxy having up to 6 C atoms, and at least one of L ²¹ and L ^{22 is} F.

X ² is more preferably F, Cl, CF 3, OCF 3, or OCHF 2.

The medium according to the invention particularly preferably contains one or more compounds selected from the compounds of the formula 11-1, II-5, II-9 and 11-12, very particularly preferably selected from the group consisting of

Sub-formulas II-1a, 11-1b, II-5a, II-5b, II-6a, II-6b, II-9a, II-9b, II-12a and II-12b.

ll-6a wherein R ^{2 has} the meaning given above and preferably n-alkyl having 1 to 7 carbon atoms.

Most preferably, the medium contains one or more compounds selected from the group of the compounds of formulas II-1b, II-5a, II-5b and II-9a.

In a preferred embodiment, the medium contains one or more compounds of general formula III wherein

R ^{3 has} the meaning given above under formula II for R ² ,

mean, preferably one or more of

and

means L ³¹ and L ³² , independently of one another H or F,

X ³ F, Cl, CN, halogenated alkyl radical, halogenated

Z ³ at each occurrence independently of each other -CH 2 CH 2 -,

-COO-, trans- CH = CH-, trans- -CF = CF-, -CH ₂ 0-, -C = C- or a single bond, preferably one or both represent a single bond.

The compounds of the formula III are preferably selected from the group of the compounds of the formulas III-1 to III-9:

X ³ F, Cl, halogenated alkyl or halogenated alkoxy with up to

6 carbon atoms and preferably F or OCF3 means.

Particularly preferably, the medium contains one or more

Compounds selected from the group of compounds of the formulas IM-1 and MI-3.

Most preferably, the medium contains one or more

F

wherein R ³ preferably denotes n-alkyl having 1 to 7 carbon atoms.

The medium according to the invention preferably contains one or more compounds of the formula IV

independently of one another have the meaning given above for R ² under formula II, preferably R ^{41 is} alkyl and R ^{42 is} alkyl or alkoxy or R ^{4 is} alkenyl and R ^{42 is} alkyl, mean,

preferably one or more of

means or mean

Z ⁴¹ and Z ^{42 are} independently of each other -CH 2 CH 2 -,

-COO-, trans- -CH = CH-, trans- -CF = CF-, -CH2O-, -CF2O-, -C ^ C- or a single bond, preferably one or more of them signifies a single bond and p is 0, 1 or 2, preferably 0 or 1. 5 The compounds of the formula IV are preferably selected from the group of the compounds IV-1 to IV-13

wherein

R ⁴¹ and R ⁴² independently of one another n-alkyl having 1 to 7 carbon atoms and

H or F means, preferably F.

The medium according to the invention particularly preferably contains one or more compounds selected from the group of compounds IV-5, IV-8 and IV-11.

In a further preferred embodiment, the

Medium according to the invention one or more compounds of the formula V

wherein R ⁵¹ and R ⁵² independently of one another have the meanings given above under formula II for R ² , preferably R ^{5 is} alkyl and R ^{52 is} alkyl or alkenyl,

preferably one or more of

mean,

Z ⁵ and Z ⁵² independently of one another and in the case of Z ⁵¹ also occur independently of one another -CHHCH-, -COO-, trans-CHCHCH-, trans-CF =CF-, -CH ₂ O-, or a Single bond, preferably one or more of them is a single bond

means / mean, and r is 0, 1 or 2, preferably 1 or 2, particularly preferably 1.

In a further preferred embodiment, the medium contains one or more compounds selected from the group of the compounds of the formulas V-1 and V-2

wherein R ⁵¹ and R ^{52 have} the respective meanings given above under formula V and are preferably alkyl

The compounds of the formulas I to V, IA and IB are prepared by methods known per se, as described in the literature (for example in the standard works such as Houben-Weyl, Methods of Organic Chemistry, Georg Thieme Verlag, Stuttgart), under

Reaction conditions which are known and suitable for the said reactions. One can also make use of known per se, not mentioned here variants. The compounds of the formula I and IA are known, for example, from DE 10 2008 062858 A1. The compounds of the formula IB are disclosed in DE 102223061 A1.

Another object of the invention are electro-optical components, in particular light valves, based on the TN or STN effect, with two plane-parallel support plates which form a cell with a border, integrated non-linear elements for switching individual pixels on the carrier plates and one in the Cell nematic liquid crystal mixture having positive dielectric anisotropy and high resistivity containing the media of the invention and the use of these media for electro-optic

Purposes.

Another object of the invention is its use in

Lighting equipment for motor vehicles and in

Liquid crystal displays, in particular TN, STN or MFK displays.

Another object of the invention are lighting devices for motor vehicles and electro-optical displays that contain these components.

The liquid-crystal mixtures according to the invention enable a significant expansion of the available parameter space. The achievable combinations of clearing point, phase width, low temperature viscosity, thermal and UV stability and dielectric

Anisotropy far surpass previous prior art materials.

It will be understood that by appropriate choice of the components of the blends of the invention, higher clearing points (e.g., above 150 ° C) at higher threshold voltages or lower clearing points at lower threshold voltages to obtain the other

advantageous properties can be realized. Likewise, with correspondingly low viscosities, mixtures with a larger Δε and thus lower thresholds can be obtained. The electro-optical components according to the invention preferably operate in the first

Transmission minimum according to Gooch and Tarry [C.H. Gooch and H.A. Tarry, Electron. Lett. 10, 2-4, 1974; C.H. Gooch and H.A. Tarry, Appl.

Phys., Vol. 8, 1575-1584, 1975], which in addition to particularly favorable electro-optical properties, such as high slope of the curve and low angle dependence of the contrast (DE-PS 30 22 818) at the same threshold voltage as in an analog display in second minimum, a smaller dielectric anisotropy is sufficient. As a result, significantly higher specific resistances can be achieved using the mixtures according to the invention in the first minimum for mixtures with cyano compounds. By a suitable choice of the individual components and their proportions by weight, the person skilled in the art can set the birefringence required for a given layer thickness of the component by simple routine methods.

Measurements of the Voltage Holding Ratio (HR) [p. Matsumoto et al., Liquid

Crystals 5, 1320 (1989); K. Niwa et al., Proc. SID Conference, San

Francisco, June 1984, p. 304 (1984); G. Weber et al., Liquid Crystals 5, 1381 (1989)] have shown that mixtures according to the invention containing compounds of the formula BO have a significantly smaller decrease in HR with increasing temperature than analogous mixtures comprising instead of the compounds of the formula BO:

The UV stability of the mixtures according to the invention is also considerably better, i. they show a much smaller decrease in HR under UV exposure.

The liquid-crystal mixtures according to the invention make it possible, while maintaining the nematic phase, to -20 ° C. and preferably to -30 ° C., particularly preferably to -40 ° C., clearing points above 120 ° C.,

preferably above 130 ° C., more preferably above 140 ° C., simultaneously achieving dielectric anisotropy values Δε> 6, preferably> 8, and a high value for the specific resistance, whereby excellent light valves according to the invention can be achieved. In particular, the mixtures are characterized by low operating voltages. The TN thresholds are below 2.0 V, preferably below 1, 5 V, more preferably <1, 3 V.

The liquid-crystal mixtures according to the invention have an optical anisotropy (Δη) in the range from 0.050 to 0.110, preferably from 0.060 to 0.100, particularly preferably from 0.080 to 0.090. The rotational viscosity γι of the mixtures according to the invention at 20 ° C is preferably <350 mPa-s, more preferably <300 mPa-s. The nematic phase range is preferably at least 140 K,

in particular at least 180 K. This range preferably extends at least from -40 ° to + 140 °.

Preferred embodiments are given below:

The medium contains one or more compounds of the formula BO in a total concentration in the range from 5 to 35%, preferably from 10 to 30%, particularly preferably from 15% to 25%.

The medium contains one or more compounds of the formula I in a total concentration in the range from 20 to 70%, preferably from 25 to 60%, particularly preferably from 30% to 50%.

- The total concentration of compounds of formula II in the medium is 10% to 40%, preferably 15% to 35% and particularly preferably 20% to 30%.

- The medium contains one or more compounds of formula 11-1 b.

The total concentration of the compounds of the formulas IV-1, IV-2, IV-3, IV-4, IV-5 and IV-6 in the medium is 3 to 20, preferably 5 to 18, particularly preferably 8 to 16%. Preferably, the medium contains at least one compound of formula IV-5.

The total concentration of compounds of the formulas IV-7, IV-8, IV-9, IV-10, IV-11, IV-12 and IV-13 is 2% to 20%, preferably 4% to 16% and more preferably 6% to 13%. The medium preferably contains at least one compound of the formula IV-8 or IV-11. The proportion of the compounds having unsaturated side chains (R is alkenyl or alkynyl) in the medium is 0 to 10%, preferably 0 to 5%, particularly preferably 0 to 2%.

It has been found that the inventive

Liquid crystal mixtures using one or more

Compared with the prior art, compounds selected from the compounds of the formulas BO, I to V, IA and IB lead to low values for the birefringence, at the same time observing broad nematic phases, high clearing points and low transition temperatures smectic-nematic, which improves the storage stability becomes. Preference is given in particular to mixtures which, in addition to one or more

Compounds of the formulas BO and I contain one or more compounds of the formula II, in particular compounds of the formula 11-1 b. All these compounds are colorless, stable and well miscible with each other and with other liquid crystal materials.

The optimum ratio of the compounds of the formulas BO, I to V, IA and IB depends largely on the desired properties, on the choice of the components of the formulas BO, I to V, IA and IB and the choice of further optional components.

Suitable proportions within the range given above can be easily determined on a case-by-case basis.

The total amount of compounds of the formulas BO, I to V, IA and IB in the mixtures according to the invention is not critical. The mixtures may therefore contain one or more other components to optimize various properties. However, the observed effect on the response times and the threshold voltage is generally greater the higher the total concentration of compounds of the formulas I, IA, IB, II and III. Furthermore, the higher the proportion of compounds of the formulas BO, IA, IB, III and IV, the higher the clearing point.

The construction of the light valves according to the invention from polarizers,

Electrode base plates and electrodes with surface treatment corresponds to the usual construction for such components. Here is the term The usual construction here broadly and includes all modifications and modifications of the components, in particular also matrix display elements based on poly-Si TFT or MIM.

An essential difference of the invention

However, liquid crystal valves to the usual on the basis of the twisted nematic cell is the choice of the liquid crystal parameters of the liquid crystal layer.

The preparation of the liquid crystal mixtures which can be used according to the invention is carried out in a conventional manner. In general, the desired amount of the components used in lesser amount is dissolved in the constituent of the main component, expediently at elevated temperature. It is also possible to use solutions of the components in an organic solvent, e.g. in acetone, chloroform or methanol, and the solvent after

Remove again mixing, for example by distillation.

The dielectrics may also contain further additives known to the person skilled in the art and described in the literature. For example, 0-15% pleochroic dyes or chiral dopants may be added.

C means a crystalline, S a smectic, Sc a smectic C, N a nematic and I the isotropic phase. V10 denotes the voltage for 10% transmission (viewing direction perpendicular to the disk surface), ton denotes the switch-on time and totr the switch-off time at an operating voltage corresponding to 2.0 times the value of V10. Δη denotes the optical anisotropy and n ₀ den

Refractive index. Δε denotes the dielectric anisotropy (Δε = ε \\ - ε ±, where ειι means the dielectric constant parallel to the longitudinal molecular axes and ει the dielectric constant perpendicular thereto). The electro-optical data are measured in a TN cell in the 1st minimum (i.e., at a d · Δη value of 0.5) at 20 ° C, unless expressly stated otherwise. The optical data are at 20 ° C

unless expressly stated otherwise. In the present application and in the following examples, the structures of the liquid crystal compounds are indicated by acronyms, wherein the transformation into chemical formulas according to the following Tables A and B takes place. All radicals C _n H2n + i and Cmhbm + i are straight-chain

Alkyl radicals with n or m C atoms; n and m are integers and are preferably 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12. The coding according to Table B is self-evident. In Table A is only the acronym for the main body specified. In individual cases a code for the substituents R ^{1 *} , R ^{2 *} , L ^* , L ^{2 *} and L ^{3 *} follows separately from the acronym for the main body with a rope:

Code for R ^{1 *} , R ^{1 *} R ^{2 *} L ^{1 *} L ^{2 *} L ³ R ^{2 *} , L, L ^{2 *} ,

L ^{3 *}

nOm OC _n H ₂ n ₊ 1 _m H2m + 1 HHH nO.m _n H2n + 1 OC _m H _{2m +} i HHH _nn H2n + 1 CN HHH

nOF Οΰ _η Η _2η + ι FHHH nF.FC _n H2n + 1 FHHF

nOCF ₃ C _n H2n + 1 OCF ₃ HHH nOCFs.F _n H2n + 1 OCF3 FHH

nV-Vm CnH2n ₊ 1-CH = CH- HHH Preferred mixture components are given in Tables A and B. TABLE A

CEPTP

CFU Table B:

CGBo-n-m

BCH -n.Fm CFU-nF

CBC NMF

ECCP-nm CCZU-nF

T-nFm CGU-nF

CDU-nF CGG-nF C "mH '' 2m + 1

CPZG-n-OT CC-nV-Vm

CCP-Vn-m CCG-VF

CCP-nV-m CC-nV

CCQG-n-F CC-n-V1

CCQU-nF

CCCQG nF

CCCQU nF

CCCQU-n-OT

CQCU-n-F Dec-U-n-F

CWCU nF

CWCG nF

CCOC-n-m

CPTU-nF GPTU-nF

CCGU-n-F

CUQU nF

CDUQU nF Particular preference is given to liquid-crystalline mixtures which, in addition to the compounds of the formula BO, have at least one, two, three or four

Compounds from Table B included.

Table C:

In Table C possible dopants are given, which are usually added to the mixtures of the invention.

R / S-1011

R / S-3011

CN

R / S 2011

The following Table D shows exemplary compounds that can be used as stabilizers in the media of the invention.

Table D



In a preferred embodiment of the present invention, the liquid-crystalline media contain one or more compounds of Table D.

The following examples are intended to illustrate the invention without limiting it. Above and below, percentages are by weight. All temperatures are in degrees Celsius. Mp means melting point, bp = clearing point. Furthermore, K = crystalline state, N = nematic phase, S = smectic phase and I = isotropic phase. The data between these symbols represent the transition temperatures. Δη means optical anisotropy (589 nm, 20 ° C), the flow viscosity V20 (mm ² / sec) and the rotational viscosity γι (mPa s) are each determined at 20 ° C. synthesis Examples

Example 1: 4- [2-Fluoro-4- (4-propylcyclohexyl) phenyl] -1-pentyl-

1-fluoro-3- (4-propylcyclohexene-1-yl) benzene

A solution of 37.4 g (0.21 mol) of 1-bromo-3-fluorobenzene in 225 ml

Tetrahydrofuran (THF) is added dropwise, while cooling with ice, with 128 ml of isopropylmagnesium chloride solution (2M in THF, 0.26 mol).

Subsequently, the reaction mixture for two hours at

Stirred room temperature and then added dropwise with ice cooling 30.0 g (0.21 mol) of 4-propylcyclohexanone in 200 ml of THF. The cold bath is removed and the batch is allowed to stir overnight at room temperature. The mixture is diluted with ice-water and acidified with 2N hydrochloric acid. The aqueous phase is extracted with MTB ether, the combined organic phases are washed with sat. Washed sodium chloride solution, dried over sodium sulfate, filtered and concentrated. The residue is dissolved in 500 ml of toluene and treated with 2.1 g (12 mmol) of p-toluenesulfonic acid monohydrate. The mixture is then heated under reflux for 4 h and washed after cooling with 30 ml of 0.5 M sodium hydroxide solution, dried over sodium sulfate, filtered and concentrated. The residue is filtered through silica gel with n-heptane and reacted further without further purification. 1.2 1 -fluoro-3- (4-propylcyclohexyl) benzene

A solution of 8.7 g (30.2 mmol) of 1-fluoro-3- (4-propylcyclohexene-1-yl) benzene in 30 ml of toluene is hydrogenated to a standstill on palladium activated carbon catalyst. The catalyst is filtered off, the filtrate is concentrated and the resulting product is then filtered through silica gel with n-heptane. 1-Fluoro-3- (4-propylcyclohexyl) benzene is obtained as a colorless oil.

1.3 4- [2-Fluoro-4- (4-propylcyclohexyl) phenyl] -1-pentylbicyclo [2.2.2] octane

Sulfuric acid (25 mL, 95-97proz.) Is introduced at room temperature and treated dropwise with a melt of 1-pentyl-bicyclo [2.2.2] octan-4-ol and 1-fluoro-3- (4-propylcyclohexyl) benzene. After 1 h, another 10 ml of sulfuric acid are added and the mixture is stirred for 3 h at room temperature. The mixture is then heated for 30 min at 30 ° C and then poured directly on ice. The aqueous phase is extracted with ether, the combined organic phases are washed with water, dried over sodium sulfate and concentrated. The residue is filtered through silica gel with n-heptane. The product obtained is crystallized from ethanol and filtered off with suction. 4- [2-fluoro-4- (4- propylcyclohexyl) phenyl] -1-pentylbicyclo [2.2.2] octane as colorless

Solid. H NMR (400 MHz, CDClA):

δ (ppm) = 0.91 (dd, J = 7.1, 7.1 Hz, 3H), 0.92 (dd, J = 7.1, 7.1 Hz, 3H), 0.99-1 , 51 (m, 23H), 1, 84-1, 93 (m, 10H), 2.43 (dddd, J = 12.1, 12.1, 3.3, 3.3 Hz, 1H), 6.84 (dd, J = 14.3, 1.8 Hz, 1H), 6.91 (dd, J = 8.1, 1.9 Hz, 1H), 7.12 (dd, J = 8.4, 8.4 Hz, 1H); ¹⁹ F NMR (376 MHz, CDCl 3): δ (ppm) = - 109.1 (dd, J = 14.3, 8.8 Hz); ¹³ C NMR (101 MHz, CDC): δ (ppm) = 14.3, 14.6, 20.2, 22.9, 23.5, 30.3, 30.8 (3C), 31, 5 ( 3C), 33.1, 33.6 (2C), 34.3 (2C), 34.4 (d, J = 3.3 Hz), 37.2, 39.9, 41, 9 43.9, 114.7 (d, J = 24.2 Hz), 122.1 (d, J = 2.7 Hz), 127.3 (d, J = 6.5 Hz), 133.6 (d, J = 11, 5 Hz), 147.7 (d, J = 7.9 Hz), 162.2 (d, J = 247.4 Hz).

Phase sequence: K 73 SmB 126 N 180.7 I.

In analogy to Example 1 are obtained:

Example 2: 4- [2-Fluoro-4- (4-propylcyclohexyl) phenyl] -1-propylbicyclo [2.2.2] octane

Phase sequence: K 92 SmB 159 N 179 I

Example 3: 4-r2-Fluoro-4- (4-pentyl-1-cyclohexyl) phenyl] -1-pentyl-bicyclo [2.2.2] octane

Phase sequence: K 69 SmB 173 N 192 I Mixing Examples Mixing Example M1

CCQU-2-F 14.00% Clearing point [° C]: 125.4

CCQU-3-F 16.00% Δη [589 nm, 20 ° C]: 0.0864

CCQU-5-F 10.00% Δε [1 kHz, 20 ° C]: 9.3

CCP-2F.F.F 7.00% γι [mPa.s, 20 ° C]: 286

CCP-3F.F.F 13.00%

CCP-5F.F.F 5.00%

CCP-3-1 8.00%

CBC-53F 4.00%

CBC-33F 3.00%

CGBo-3-3 20.00%

Mix Example M2

CCQU-2-F 14.00% Clearing point [° C]: 120.2

CCQU-3-F 16.00% Δη [589 nm, 20 ° C]: 0.0851

CCQU-5-F 14.00% Δε [1 kHz, 20 ° C]: 10.4

CCP-2F.F.F 8.00% γι [mPa.s, 20 ° C]: 287

CCP-3F.F.F 14.00%

CCP-5F.F.F 5.00%

CBC-53F 6.00%

CBC-33F 3.00%

CGBo-3-3 20.00%

Claims

claims

Liquid-crystalline medium, characterized in that

or several compounds of the formula BO

contains, in which the individual radicals have the following meanings:

R ^{0 is} an alkyl or alkoxy radical having 1 to 15 C atoms, where in these radicals one or more H atoms may be replaced by F, Cl, or CN and also one or more CH 2 groups each independently

- ^ - -O- 0O-.

-C = C-, -O-, -CO-O- or -O-CO- can be replaced so that O atoms are not directly linked,

R ^{02 is} an alkyl or alkoxy radical having 1 to 15 C atoms, wherein in these radicals one or more H atoms may be replaced by Cl or CN and one or more CH 2 groups each independently

-C = C-, -CH = CH-, -O-, -CO-O- or -O-CO- may be replaced so that O atoms are not directly linked to each other,

A ¹ , A ² are each independently 1,4-cyclohexanediyl in which one or two CH 2 groups can be replaced by O so that O atoms are not linked to one another, -CH ₂ CH ₂ -, -CF ₂ CF ₂ -, -C (O) O-, -OC (O) -, frans-CH = CH-, frans-CF = CF-, -CH 2 O-, -OCH 2 -, or a

Single bond,

F, Cl, CF3, or alkyl or alkoxy having 1 to 6 carbon atoms, one or more H atoms of which may be replaced by F,

0 or 1 and

0, 1, 2, 3 or 4.

Liquid-crystalline medium according to claim 1, characterized

in that the compounds of the formula BO are selected from compounds of the subformulae BO-1 and BO-2

wherein A ¹ and A ^{2 have} the meaning given in claim 1 and R ⁰¹ , R ⁰² alkyl having 2 to 5 C atoms Z ^{1 is} a single bond

YF, and s 0, 1 or 2 mean.

3. Liquid-crystalline medium according to claim 1 or 2 characterized

characterized in that it contains one or more compounds of formula I.

wherein

R ^{1 is} an alkyl or alkoxy radical having 1 to 15 C atoms, where in these radicals one or more H atoms may be replaced by F and also one or more CH 2 groups in each case independently of one another by ^ - '- <> - ■ ^ Χ ^ "- ~ C = C-, -CH = CH-, -O-, -CO-O- or -O-CO- may be replaced so that O atoms are not directly linked to each other,

the same or different at every occurrence

independently of one another H or F,

X ¹ F, Cl, CN, halogenated alkyl, halogenated

Alkenyl radical, halogenated alkoxy radical or halogenated alkenyloxy radical having up to 6 C atoms.

Liquid-crystalline medium according to claim 3, characterized

characterized in that it contains one or more compounds selected from the group of compounds 1-1 to I-5,

1-1

wherein R ¹ , X ¹ , L ¹ and L ^{12 have} the meaning given in claim 3 and L ¹³ and L ¹⁴ independently of one another are H or F.

5. Medium according to one or more of claims 1 to 4, characterized in that it contains one or more compounds of formula II

II wherein

R ^{2 is} an alkyl or alkoxy radical having 1 to 15 C atoms, wherein in these radicals one or more H atoms may be replaced by F and also one or more Chte groups each independently of one another by -O- ·. -C = C-, -CH = CH-, -

O, -CO-O- or -O-CO- can be replaced so that O atoms are not directly linked to one another,

the same or different at every occurrence

^F or L ²¹ and L ²² independently of one another H or F,

F, Cl, CN, halogenated alkyl, halogenated

-CH ₂ CH ₂ -, -CF ₂ CF ₂ -, -COO-, trans-CH = CH-,

trans-CF = CF-, -CH 2 O- or a single bond,

6. Medium according to claim 5, characterized in that the

Compounds of formula II are selected from the group of compounds 11-1 to 11-14

R ² n-alkyl with up to 7 C atoms,

L ²¹ and L ^{22 are} independently H or F and

X ² F, Cl, halogenated alkyl or halogenated aikoxy having up to 6 C atoms

mean.

Medium according to one or more of Claims 1 to 6, characterized in that it contains one or more compounds of the formula IV,

wherein

R ⁴¹ , R ⁴² independently of each other in claim 6 for R ²

have the meaning given

with each occurrence independent of each other

each occurrence independently of one another represents -CH 2 CH 2 -, -COO-, trans -CH = CH-, trans- -CF = CF-, -CH 2 O-, -CF 2 O-, -C = C- or a single bond, and

0, 1 or 2 means

Medium according to claim 7, characterized in that the

Compounds of the formula IV are selected from the compounds of the formulas IV-1 to IV-13

R ⁴¹ - (WN IV-5 independently of one another n-alkyl having 1 to 7 carbon atoms and

H or F means.

Use of the liquid-crystalline medium according to one or more of Claims 1 to 8 for electro-optical purposes.

10. Use according to claim 9 in Flüssigkristallichtventilen for

Lighting equipment for motor vehicles or in

Liquid crystal displays.

11. Electro-optical component containing a liquid-crystalline

Medium according to one or more of claims 1 to 8.

12. An electro-optical device according to claim 11, wherein the

Component is a Flüssigknstallichtventil.

13. Lighting device for motor vehicles containing a

Liquid crystal light valve according to claim 12.

14. A liquid crystal display comprising a liquid crystal light valve according to claim 12.

15. Compounds of formula BO as defined in claim 1. 16. Compounds according to claim 15, wherein the compounds

are selected from the group of compounds of the formulas BO-1 and BO-2

wherein R ⁰¹ , R ⁰² , A ¹ , A ² , ZY and s have the meanings given in claim 1.

17. Compounds according to claim 15 or 16, wherein the compounds are selected from the group of the compounds of the formulas BO-1a-1 to ΒΟ-2Ϊ-4

O -i / BO-1 b-1