TWI504730B - Liquid-crystalline medium and liquid-crystal display - Google Patents

Description

Liquid crystal medium and liquid crystal display

The present invention relates to liquid crystal media and liquid crystal displays comprising the same, and more particularly to displays that are addressed by active matrix and in particular to twisted nematic (TN), in-plane switching (IPS) or fringe field switches (FFS) ) type display.

Liquid crystal displays (LCDs) can be used in many areas of information display. The LCD can be used for both direct view and projection displays. Electro-optical modes such as twisted nematic (TN), super twisted nematic (STN), optically compensated bend (oCB), and electronically controlled birefringence (ECB) modes, as well as various modifications thereof, and other modes are used. All of these modes utilize an electric field that is substantially perpendicular to the substrate or liquid crystal layer. In addition to these modes, there are electro-optic modes that utilize an electric field substantially parallel to the substrate or liquid crystal layer, such as an in-plane switching (IPS) mode (e.g., for example, German Patent No. 40 00 451 and European Patent No. 0 588). In the FFS mode, there is a strong "fringe field", that is, a strong electric field near the edge of the electrode and an electric field having a strong vertical component and a strong horizontal component throughout the cell. The latter two electro-optical modes are particularly useful for LCDs in modern desktop monitors and are intended for use in displays in televisions and multimedia applications. The liquid crystal of the present invention is preferably used in displays of this type. In general, a dielectric positive liquid crystal medium having a relatively low dielectric anisotropy value is used in an FFS display, but in some cases, a liquid crystal medium having a dielectric anisotropy of only about 3 or even lower may be used. In the IPS display.

For such displays, there is a need for novel liquid crystal media having improved properties. For many types of applications, it is especially necessary to improve the addressing time. Therefore, there is a need for liquid crystal media having a lower viscosity (η), especially a lower rotational viscosity (γ ₁ ). Especially for monitor applications, the rotational viscosity should be 80 mPa ‧ or lower, preferably 60 mPa ‧ or lower and especially 55 mPa ‧ or lower In addition to this parameter, the medium must have a nematic phase range of appropriate width and position and appropriate birefringence (Δn), and the dielectric anisotropy (Δε) should be sufficiently high to achieve a suitably low operating voltage. Δε should preferably be greater than 2 and preferably greater than 3, but preferably no greater than 15 and especially no greater than 12, which would therefore prevent at least a slightly higher resistivity.

For applications as displays for notebook computers or other mobile applications, the rotational viscosity should preferably be 120 mPa ‧ or less and especially preferably 100 mPa ‧ s or less. The dielectric anisotropy (Δε) here should preferably be greater than 8 and particularly preferably greater than 12.

The display of the present invention is preferably addressed by an active matrix (active matrix LCD, abbreviated as AMD), preferably by a matrix of thin film transistors (TFTs). However, the liquid crystal of the present invention can also be advantageously used in displays having other known addressing modes.

There are various display modes for various composite systems using low molecular weight liquid crystal materials and polymeric materials. By way of example, there are polymer dispersed liquid crystals (PDLC), nematically aligned phase (NCAP) and polymer network (PN) systems (as disclosed, for example, in WO 91/05 029) or axisymmetric microdomains ( ASM) system and other modes. In contrast to this, a particularly preferred mode of the invention uses such a liquid crystal medium oriented on the surface. Pretreatment is typically performed on the surfaces to achieve uniform alignment of the liquid crystal material. The display mode of the present invention preferably uses an electric field that is substantially parallel to the composite material layer.

Patent application EP 0 563 982 A2 discloses a general formula

Wherein, in each of the cases except for many other possibilities, R may represent H or an alkyl group, R' may represent H, and Y may represent an alkyl group, both n and m may represent 0, and ring A may represent 1,4-cyclohexylene, and thus both X and X' can represent H.

A liquid crystal composition suitable for an LCD and particularly suitable for an IPS display can be known, for example, from Japanese Patent No. 07-181 439 (A), European Patent No. 0 667 555, and European Patent No. 0 673 986. German Patent No. 195 09 410, German Patent No. 195 28 106, German Patent No. 195 28 107, WO 96/23 851 and WO 96/28 521. However, such compositions have serious drawbacks. Among other defects, most of them disadvantageously result in long addressing times, have insufficient resistivity values, and/or require excessive operating voltages. In addition, there is a need to improve the low temperature properties of LCDs. In this case, it is necessary to improve the operational properties as well as to improve the shelf life.

Therefore, there is an urgent need in the industry for liquid crystal media having properties suitable for practical applications, such as a wide nematic phase range, a suitable optical anisotropy Δn corresponding to the display mode used, a high Δε, and a particularly low viscosity for particularly short response times. .

Surprisingly, it has now been found that a liquid-crystalline medium having a suitably high Δε, a suitable phase range and Δn can be achieved, which does not exhibit the disadvantages of prior art materials, or at least to a significantly lesser extent.

The improved liquid crystal medium of the present invention comprises

- one or more compounds of formula I

Wherein R ¹¹ represents an alkyl group having 1 to 7 C atoms or an alkoxy group, preferably having 1 to 5 C atoms, particularly preferably an alkyl group having 1 to 3 C atoms, and R ¹² represents H or has 1 - an alkyl group of 5 C atoms, preferably an alkyl group of 1-3 C atoms, and

- a compound selected from the group of compounds of the formulae II and III, as the case may be:

Wherein R ² and R ³ independently of each other represent an alkyl group having 1 to 7 C atoms, an alkoxy group, a fluoroalkyl group or a fluoroalkoxy group, an alkenyl group having 2 to 7 C atoms, an alkenyloxy group , alkoxyalkyl or fluoroalkenyl, and R ² and R ³ preferably denote alkyl or alkenyl,

Representing each other independently each time it appears

L ₂₁ , L ₂₂ , L ³¹ and L ³² represent H or F independently of each other, and L ²¹ and/or L ³¹ preferably denotes F, and X ² and X ³ independently of each other represent halogen, and have 1-3 C atoms. alkoxy or haloalkyl or haloalkoxy having 2 or 3 C atoms or alkenyl group of alkenyl group, preferably F, Cl, -OCF ₃ or -CF _3, excellent is F, Cl or -OCF _3, Z ³ represents -CH ₂ CH ₂ -, -CF ₂ CF ₂ -, -COO-, trans-CH=CH-, trans-CF=CF-, -CH ₂ O- or a single bond, preferably -CH ₂ CH ₂ -, -COO-, trans-CH=CH- or a single bond, and is preferably -COO-, trans-CH=CH- or a single bond, and m and n independently of each other represent 0, 1, 2 or 3, m preferably represents 1, 2 or 3, and n preferably represents 0, 1 or 2, and particularly preferably 1 or 2, and

- depending on the situation, one or more compounds of formula IV

Wherein R ⁴¹ and R ⁴² independently of one another have the meaning indicated above for R ^{2 of} formula II, preferably R ⁴¹ represents alkyl and R ⁴² represents alkyl or alkoxy or R ⁴¹ represents alkenyl and R ⁴² represents alkyl ,

Independent of each other, and if Appear twice, then these are also independent of each other

Preferably one or more

Z ⁴¹ and Z ⁴² are independent of each other, and if Z ⁴¹ appears twice, then these also independently represent -CH ₂ CH ₂ -, -COO-, anti-CH=CH-, anti-CF=CF-, - CH ₂ O-, -CF ₂ O-, -C≡C- or a single bond, preferably one or more of them represents a single bond, and p represents 0, 1 or 2, preferably 0 or 1.

The compounds of formula I and IV are preferably dielectric neutral compounds which preferably have a dielectric anisotropy in the range of from -1.5 to 3.

The compounds of formula II and III are preferably dielectric positive compounds which preferably have a dielectric anisotropy greater than 3.

The liquid-crystalline medium of the present application preferably comprises a total of from 1 to 40%, preferably from 3 to 35%, and especially preferably from 5 to 25%, of a compound of formula I.

The individual compounds of formula I are used in a concentration of from 1 to 20%, preferably from 1 to 15%.

The individual compounds of formula II and / or III are used in a concentration of from 1 to 20%, preferably from 1 to 15%. These limitations apply, especially if two or more homologous compounds (i.e., compounds of the same formula) are used in each case. If only a single substance of a compound of the formula (i.e., only one homolog) is used, its concentration may range from 2 to 20%, preferably from 3 to 14%.

In a preferred embodiment of the invention, the medium of the invention comprises in each case one or more compounds of the formula I selected from the group of compounds of the formulae I-1 to I-3, preferably of the formula I-2:

Wherein R ¹¹ has the meaning indicated above for formula I and preferably represents methyl, n-propyl or n-pentyl, and especially preferably n-propyl.

The medium of the present invention preferably comprises one or more dielectric positive compounds selected from Groups II and III having a dielectric anisotropy greater than 3, in addition to a compound selected from the group consisting of a compound of formula I, or a group of preferred subtypes thereof.

In a preferred embodiment of the invention, the medium of the invention comprises one or more compounds selected from the group of compounds of the formulae II-1 to II-4, preferably of the formulae II-1 and/or II-2:

Wherein each parameter has the corresponding meaning indicated above for Formula II, and L ²³ and L ²⁴ independently represent H or F, preferably L ²³ represents F, and Targeted One of the meanings given, and in the case of Formulas II-1 and II-4, X ² preferably represents F or OCF ₃ , especially preferably F, and in the case of Formula II-3 versus , preferably independent of each other

It does not include a compound of formula I, and/or a compound selected from the group of compounds of formulas III-1 and III-2:

Each of these parameters has the meaning given for Formula III.

In a preferred embodiment, the medium of the present invention or, in addition to the compound of Formula III-1 and/or III-2, may comprise one or more compounds of Formula III-3.

Wherein each parameter has the above corresponding meaning, and the parameters L ³¹ and L ³² are independent of each other and independent of other parameters and represent H or F.

The medium of the present invention preferably comprises one or more compounds selected from the group of compounds of the formulae II-1 to II-4, wherein both L ²¹ and L ²² and/or L ²³ and L ²⁴ represent F.

In a preferred embodiment, the medium comprises one or more compounds selected from the group of compounds of Formula II-2 and II-4, wherein all of L ²¹ , L ²² , L ²³ and L ²⁴ represent F.

Preferably, the medium comprises one or more compounds of formula II-1. The compound of formula II-1 is preferably selected from the group of compounds of formula II-1a to II-1e:

Wherein each parameter has the above corresponding meaning, and L ²³ to L ²⁶ are independent of each other and independent of other parameters and represent H or F, and preferably in formulas II-1a and II-1b, both L ²¹ and L ²² represent F In Formulas II-1c and II-1d, both L ²¹ and L ²² indicate that F and/or both L ²³ and L ²⁴ represent F, and in Formula II-1e, L ²¹ , L ²² and L ²⁵ Indicates F, and in each case the other parameters have the corresponding meanings given above.

Particularly preferred compound of formula II-1

Wherein R ² has the above meaning.

The medium is extremely preferably one or more compounds selected from the group of compounds of the formulae II-1a-1, II-1a-2, II-1b-1 and II-1d-1.

Preferably, the medium comprises one or more compounds of formula II-2, preferably selected from the group of compounds of formula II-2a to II-2j:

Wherein each parameter has the corresponding meaning indicated above, and L ²⁵ to L ²⁸ independently represent H or F, preferably both L ²⁷ and L ²⁸ represent H, especially preferably L ²⁶ represents H, and other parameters have the above Corresponding meaning, and does not include the compound of formula I.

The medium of the present invention preferably comprises one or more compounds selected from the group of compounds of the formulae II-2a to II-2j, wherein both L ²¹ and L ²² represent F and/or both L ²³ and L ²⁴ represent F and other parameters have the corresponding meanings given above.

In a preferred embodiment, the medium of the present invention comprises one or more compounds selected from the group of compounds of the formulae II-2a to II-2j, wherein L ²¹ , L ²² , L ²³ and L ²⁴ all represent F and others The parameters have the corresponding meanings given above.

Particularly preferred compounds of formula II-2 are those of the formula:

Wherein R ² and X ² have the above meanings, and X ² preferably represents F.

The medium is extremely preferably one or more compounds selected from the group of compounds of the formulae II-2a-1, II-2f-1, II-2i-1 and II-2j-1.

The medium of the present invention preferably comprises one or more compounds of formula II-3, preferably selected from the group of compounds of formula II-3a to II-3c:

Wherein each parameter has the above corresponding meaning, and both L ²¹ and L ²² preferably represent F.

In a preferred embodiment, the medium of the present invention comprises one or more compounds of the formula II-4, preferably of the formula II-4a

Wherein each parameter has the meaning given above, and X ² preferably represents F or OCF ₃ , especially preferably F.

The medium of the present invention preferably comprises one or more compounds of the formula III-1, preferably selected from the group of compounds of the formulae III-1a and III-1b:

Wherein each parameter has the corresponding meaning above, and the parameters L ³³ and L ³⁴ are independent of each other and independent of the other parameters and represent H or F.

The medium of the invention preferably comprises one or more compounds of the formula III-1a, preferably selected from the group of compounds of the formulae III-1a-1 to III-1a-6:

Wherein R ³ has the above meaning.

The medium of the present invention preferably comprises one or more compounds of the formula III-Ib, preferably selected from the group of compounds of the formulae III-1b-1 to III-1b-4, preferably of the formula III-1b-4:

Wherein R ³ has the above meaning.

The medium of the present invention preferably comprises one or more compounds of the formula III-2, preferably selected from the group of compounds of the formulae III-2a to III-2j:

Wherein each parameter has the meaning given above and preferably wherein each parameter has the corresponding meaning indicated above, and the parameters L ³³ , L ³⁴ , L ³⁵ and L ³⁶ are independent of each other and independent of the other parameters and represent H or F.

The medium is extremely preferably one or more compounds selected from the group of compounds of the formulae III-2a, III-2d, III-2f, III-2g and III-2i.

The medium of the present invention preferably comprises one or more compounds of the formula III-2a, preferably selected from the group of compounds of the formulae III-2a-1 to III-2a-5, preferably of the formula III-2a-4:

Wherein R ³ has the above meaning.

The medium of the present invention preferably comprises one or more compounds of the formula III-2b, preferably selected from the group of compounds of the formulae III-2b-1 and III-2b-2, preferably of the formula III-2b-2:

Wherein R ³ has the above meaning.

The medium of the invention preferably comprises one or more compounds of the formula III-2c, preferably selected from the group of compounds of the formulae III-2c-1 to III-2c-5:

Wherein R ³ has the above meaning.

Preferably, the medium of the present invention comprises one or more compounds selected from the group consisting of the compounds of the formulae III-2d and III-2e, preferably selected from the group consisting of the formulae III-2d-1 and III-2e-1, preferably the formula III-2d- 1 group of compounds:

Wherein R ³ has the above meaning.

The medium of the invention preferably comprises one or more compounds of the formula III-2f, preferably selected from the group of compounds of the formulae III-2f-1 to III-2f-5:

Wherein R ³ has the above meaning.

The medium is extremely preferably one or more compounds selected from the group of compounds of the formulae III-2f-1, III-2f-2 and III-2f-4.

Preferably, the medium of the present invention comprises one or more compounds of formula III-2g, preferably selected from the group of compounds of formula III-2g-1 to III-2g-5:

Wherein R ³ has the above meaning.

The medium is extremely preferably one or more compounds selected from the group of compounds of the formulae III-2g-2, III-2g-4 and III-2g-5, preferably of the formulae III-2g-2 and III-2g-5.

The medium of the present invention preferably comprises one or more compounds of the formula III-2h, preferably selected from the group of compounds of the formulae III-2h-1 to III-2h-3, preferably of the formula III-2h-3:

Wherein each parameter has the meaning given above, and X ³ preferably represents F.

The medium of the present invention preferably comprises one or more compounds of the formula III-2i, preferably selected from the group of compounds of the formulae III-2i-1 and III-2i-2, preferably of the formula III-2i-2:

Wherein each parameter has the meaning given above, and X ³ preferably represents F or OCF ₃ .

The medium of the present invention preferably comprises one or more compounds of the formula III-2j, preferably selected from the group of compounds of the formulae III-2j-1 and III-2j-2, preferably of the formula III-2j-1:

Each of the parameters has the meaning given above.

Alternatively or in addition to a compound of formula III-1 and/or III-2, the medium of the invention may comprise one or more compounds of formula III-3

Each of the parameters has the corresponding meaning indicated above for Formula III.

Preferably, the compounds are selected from the group of Formulas III-3a and III-3b:

Wherein R ³ has the above meaning.

The liquid crystal medium of the present invention preferably comprises a dielectric neutral component, component C. The dielectric anisotropy of this component is in the range of -1.5 to 3. It preferably comprises a dielectric neutral compound having a dielectric anisotropy in the range of from -1.5 to 3, more preferably consists essentially of, even more preferably consists essentially of, and particularly preferably consists entirely of. Preferably, the component comprises one or more dielectric neutral compounds of the formula IV having a dielectric anisotropy in the range of from -1.5 to 3, more preferably consisting essentially of, even better consisting essentially of, and excellently complete It consists of it.

The dielectric neutral component (component C) preferably comprises one or more compounds selected from the group of compounds of formula IV-1 to IV-6:

Wherein R ⁴¹ and R ⁴² have the corresponding meanings indicated above for formula IV, and in formulas IV-1, IV-5 and IV-6 R ⁴¹ preferably denotes alkyl or alkenyl, preferably alkenyl, and R ⁴² preferably represents an alkyl group or an alkenyl group, preferably an alkyl group, and in the formula IV-2, R ⁴¹ and R ⁴² preferably represent an alkyl group, and in the formula IV-4, R ⁴¹ preferably represents an alkyl group or an alkenyl group, more preferably an alkyl group, and R ⁴² preferably represents an alkyl group or an alkoxy group, more preferably an alkoxy group.

The dielectric neutral component (component C) preferably comprises one or more compounds selected from the group of compounds of formulae IV-1, IV-4, IV-5 and IV-6, preferably one or more of formula IV- 1 compound and one or more compounds selected from the group of formulae IV-4 and IV-5, more preferably one or more compounds of each of formulas IV-1, IV-4 and IV-5 and preferably one or more A compound of each of IV-1, IV-4, IV-5 and IV-6.

In a preferred embodiment, the medium of the present invention comprises one or more compounds of the formula IV-5, preferably more preferably selected from the group consisting of the following formula: CCP-Vn and/or CCP-nV-m and/or CCP -Vn-m, better CCP-Vn and / or CCP-V2-n and excellently selected from the group of CCP-V-1 and CCP-V2-1. The definitions of such abbreviations (acronyms) are set forth in Table D below or may be obtained from Tables A through C.

In a likewise preferred embodiment, the medium of the present invention comprises one or more compounds of the formula IV-1, more preferably selected from the group consisting of the following subformulae: the formula CC-nm, CC-nV, CC-n-Vm, CC-VV, CC-V-Vn and/or CC-nV-Vm, better CC-nV and/or CC-n-Vm and excellently selected from CC-3-V, CC-4-V, a group of CC-5-V, CC-3-V1, CC-4-V1, CC-5-V1, CC-3-V2 and CC-V-V1 and especially preferably selected from the group consisting of CC-3-V, CC Groups of -3-V1, CC-4-V1 and CC-5-V1. The definitions of such abbreviations (acronyms) are set forth in Table D below or may be obtained from Tables A through C.

In another preferred embodiment of the invention (which may be the same or different from the previous embodiment), the liquid crystal mixture of the invention comprises a compound of formula IV selected from the group consisting of IV-1 to IV-6 as described above and optionally Groups of compounds of formula IV-7 to IV-13:

Wherein R ⁴¹ and R ⁴² independently of each other represent an alkyl group having 1 to 7 C atoms, an alkoxy group, a fluoroalkyl group or a fluoroalkoxy group, an alkenyl group having 2 to 7 C atoms, an alkenyloxy group , alkoxyalkyl or fluoroalkenyl, and L ⁴ represents H or F.

In a preferred embodiment, the medium of the present invention comprises one or more compounds of the formula IV-8, more preferably selected from the group consisting of the following formula: CPP-3-2, CPP-5-2 and CGP-3 -2, more preferred CPP-3-2 and / or CGP-3-2 and extremely good CPP-3-2. The definitions of such abbreviations (acronyms) are set forth in Table D below or may be obtained from Tables A through C.

The liquid crystal medium of the present invention preferably comprises one or more compounds of the formula V

Wherein R ⁵¹ and R ⁵² independently of one another have the meaning indicated above for R ^{2 of} formula II, preferably R ⁵¹ represents alkyl and R ⁵² represents alkyl or alkenyl, And if it appears twice, it stands independently of each other

Preferably one or more

Z ⁵¹ and Z ⁵² are independent of each other, and if Z ⁵¹ occurs twice, then these also independently represent -CH ₂ CH ₂ -, -COO-, anti-CH=CH-, anti-CF=CF-, - Preferably, one or more of CH ₂ O-, -CF ₂ O- or a single bond represents a single bond, and r represents 0, 1 or 2, preferably 0 or 1, particularly preferably 1.

The compound of formula V is a preferred dielectric neutral compound having a dielectric anisotropy in the range of from -1.5 to 3.

The medium of the present invention comprises one or more compounds selected from the group of compounds of formula V-1 and V-2:

Wherein R ⁵¹ and R ⁵² have the corresponding meanings indicated above for formula V, and R ⁵¹ preferably represents an alkyl group, and in formula V-1, R ⁵² preferably represents an alkenyl group, preferably -(CH ₂ ) ₂ -CH=CH-CH ₃ , and in the formula V-2, R ⁵² preferably represents an alkyl group or an alkenyl group, preferably -(CH ₂ ) ₂ -CH=CH ₂ or -(CH ₂ ) ₂ -CH= CH-CH ₃ .

The medium of the present invention preferably comprises one or more compounds selected from the group of compounds of the formulae V-1 and V-2, wherein R ⁵¹ preferably represents an n-alkyl group, and in the formula V-1, R ⁵² preferably represents an alkenyl group. And in the formula V-2, R ⁵² preferably represents an n-alkyl group.

In a preferred embodiment, the medium of the present invention comprises one or more compounds of the formula V-1, more preferably selected from the group of the subformulae PP-n-2V and PP-n-2Vm, even more preferably selected from the group consisting of Its subgroup PP-1-2V and / or PP-1-2V1 group. The definitions of such abbreviations (acronyms) are set forth in Table D below or may be obtained from Tables A through C.

In a preferred embodiment, the medium of the present invention comprises one or more compounds of the formula V-2, more preferably the subtypes PGP-nm, PGP-n-2V and PGP-n-2Vm, and even more preferably the subtype PGP- 3-m, PGP-n-2V and PGP-n-V1, excellently selected from PGP-3-2, PGP-3-3, PGP-3-4, PGP-3-5, PGP-1-2V , PGP-2-2V and PGP-3-2V. The definitions of such abbreviations (acronyms) are set forth in Table D below or may be obtained from Tables A through C.

Alternatively or in addition to a compound of formula II and / or III, the medium of the invention may comprise one or more dielectric positive compounds of formula VI

Wherein R ⁶ represents an alkyl group having 1 to 7 C atoms, an alkoxy group, a fluoroalkyl group or a fluoroalkoxy group, an alkenyl group having 2 to 7 C atoms, an alkenyloxy group, an alkoxyalkyl group Or a fluoroalkenyl group, and is preferably an alkyl or alkenyl group, to Express independently of each other

L ⁶¹ and L ⁶² each independently represent H or F, preferably L ⁶¹ represents F, and X ⁶ represents halogen, haloalkyl or alkoxy having 1-3 C atoms or halogen having 2 or 3 C atoms Alkenyl or alkenyloxy, preferably F, Cl, -OCF ₃ or -CF ₃ , very preferably F, Cl or -OCF ₃ , Z ⁶ represents -CH ₂ CH ₂ -, -CF ₂ CF ₂ - , -COO-, trans-CH=CH-, trans-CF=CF-, -CH ₂ O- or -CF ₂ O-, preferably -CH ₂ CH ₂ -, -COO- or anti-CH=CH - and preferably -COO- or anti-CH=CH-, and q represents 0 or 1.

The medium of the present invention comprises one or more compounds of formula VI, preferably selected from the group of compounds of formula VI-1 and VI-2:

Wherein each parameter has the above corresponding meaning, and the parameters L ⁶³ and L ⁶⁴ are independent of each other and independent of other parameters and represent H or F, and Z ⁶ preferably represents -CH ₂ -CH ₂ -.

Preferably, the compound of formula VI-1 is selected from the group of compounds of formulae VI-1a and VI-2d:

Wherein R ⁶ has the above meaning.

Preferably, the compound of formula VI-2 is selected from the group of compounds of formula VI-2a to VI-2d:

Wherein R ⁶ has the above meaning.

Furthermore, the liquid crystal medium of the present invention may comprise one or more compounds of the formula VII

Wherein R ⁷ has the meaning indicated above for R ² of formula II, and is present

And others have the same meaning or are independent of each other

Z ⁷¹ and Z ⁷² independently of each other represent -CH ₂ CH ₂ -, -COO-, trans-CH=CH-, trans-CF=CF-, -CH ₂ O-, -CF ₂ O- or a single bond, One or more of them represent a single bond and both preferably represent a single bond, t represents 0, 1 or 2, preferably 0 or 1, more preferably 1, and X ⁷ has the above X for Formula II ² means the meaning, or may have the meaning specified for R ⁷ independently of R ⁷ .

The compound of formula VII is a preferred dielectric positive compound.

Furthermore, the liquid crystal medium of the present invention may comprise one or more compounds of the formula VIII

Wherein R ⁸¹ and R ⁸² independently of each other have the meaning indicated above for R ^{2 of} formula II, and

Z ⁸¹ and Z ⁸² independently of each other represent -CH ₂ CH ₂ -, -COO-, trans-CH=CH-, trans-CF=CF-, -CH ₂ O-, -CF ₂ O- or a single bond. One or more of them represent a single bond and both of them represent a single bond, and L ⁸¹ and L ⁸² independently represent CF or N, preferably one or both of L ⁸¹ and L ⁸² represent CF and Both of them represent CF, and s represents 0 or 1.

The compound of formula VIII is preferably a dielectric negative compound.

The medium of the present invention preferably comprises one or more compounds of formula VIII, preferably selected from the group of compounds of formula VIII-1 to VIII-3:

Wherein R ⁸¹ and R ⁸² have the corresponding meanings indicated above for formula VIII.

In the formulae VIII-1 to VIII-3, R ⁸¹ preferably represents an n-alkyl group or a 1E-alkenyl group and R ⁸² preferably represents an n-alkyl group or an alkoxy group.

The liquid-crystalline medium of the present invention preferably comprises one or more compounds selected from the group of compounds of the formulae I to VIII, preferably the formulae I to VII and more preferably the compounds of the formulae I and II and/or III and/or IV and/or VI. These are particularly preferably composed primarily of such compounds, even more preferably consisting essentially of such compounds and which are excellently composed entirely of such compounds.

In the present application, reference to "comprising" a composition means that the relevant entity (i.e., medium or component) preferably comprises said total concentration of 10% or more and preferably 20% or more. Etc.) Component or compound.

In this case, "mainly composed of" means that the related entity contains 55% or more, preferably 60% or more, and preferably 70% or more of the above-mentioned components or compounds.

In this case, "consisting essentially of" means that the related entity comprises 80% or more, preferably 90% or more, and preferably 95% or more of the said component or compound.

In this case, "substantially consists entirely of" or "completely consists of" means that the relevant entity contains 98% or more, preferably 99% or more, and preferably 100.0% of the said (etc.) Component or compound.

Other liquid crystal starting compounds not specifically mentioned above may also be used in the medium of the invention as needed and advantageously. Such compounds are well known to those skilled in the art.

The clearing point of the liquid crystal medium of the present invention is preferably 60 ° C or higher, more preferably 65 ° C or higher, particularly preferably 70 ° C or higher, and extremely preferably 75 ° C or higher.

Preferably, the nematic phase of the medium of the present invention extends at least from 0 ° C or lower to 70 ° C or higher, more preferably at least from -20 ° C or lower to 75 ° C or higher, and preferably at least from -30 ° C or Lower expansion to 75 ° C or higher, and especially at least from -40 ° C or lower to 80 ° C or higher.

The Δε of the liquid crystal medium of the present invention at 2 kHz and 20 ° C is preferably 2 or more, more preferably 4 or more, and most preferably 6 or more. Specifically, Δε is 20 or less.

The Δn of the liquid crystal medium of the present invention is preferably in the range of 0.070 or more to 0.150 or less, more preferably in the range of 0.080 or more to 0.140 or less, even at 589 nm (Na ^D ) and 20 ° C, even More preferably, it is in the range of 0.090 or more to 0.135 or less, and extremely preferably in the range of 0.100 or more to 0.130 or less.

In a preferred embodiment of the present application, the Δn of the liquid crystal medium of the present invention is preferably 0.080 or more, more preferably 0.090 or more.

In this preferred embodiment of the invention, the Δn of the liquid crystal medium is preferably in the range of 0.090 or more to 0.120 or less, more preferably in the range of 0.095 or more to 0.115 or less, and is excellent in In the range of 0.100 or higher to 0.105 or lower, Δε is preferably in the range of 5 or higher to 11 or lower, preferably 6 or higher to 10 or lower, and particularly preferably 7 or higher to 9 or lower.

In this embodiment, the nematic phase of the medium of the present invention preferably extends at least from -20 ° C or lower to 70 ° C or higher, more preferably at least from -20 ° C or lower to 70 ° C or higher. Preferably, it extends at least from -30 ° C or lower to 70 ° C or higher, and particularly at least from -40 ° C or lower to 95 ° C or higher.

According to the invention, the total concentration of all of the compounds of formula I used in the total mixture is preferably from 1% to 50%, more preferably from 1% to 30%, even more preferably from 2% to 30% and very preferably from 3% to 30%.

The total concentration of the compound selected from the group of formulae II and III in the total mixture is preferably from 2% to 60%, more preferably from 3% to 35%, even more preferably from 4% to 20% and very preferably from 5% to 15%. %.

The total concentration of the compound of formula IV used in the total mixture is preferably from 5% to 70%, more preferably from 20% to 65%, even more preferably from 30% to 60% and very preferably from 40% to 55%.

The concentration of the compound of the formula V used in the total mixture is preferably from 0% to 30%, more preferably from 0% to 15% and very preferably from 1% to 10%.

The total concentration of the compound of formula VI used in the total mixture is preferably from 0% to 50%, more preferably from 1% to 40%, even more preferably from 5% to 30% and very preferably from 10% to 20%.

The medium of the present invention may optionally contain other liquid crystal compounds to adjust physical properties. Such compounds are well known to those skilled in the art. The concentration thereof in the medium of the present invention is preferably from 0% to 30%, more preferably from 0.1% to 20%, and most preferably from 1% to 15%.

In a preferred embodiment, the concentration of the compound of formula CC-3-V in the medium of the invention may range from 50% to 65%, especially preferably from 55% to 60%.

The liquid crystal medium preferably comprises a total of from 50% to 100%, more preferably from 70% to 100% and preferably from 80% to 100% and especially from 90% to 100% of the compound of the formulae I to VII, preferably selected from the group consisting of Groups of compounds of I to VI, especially of the formulae I to V, especially of the formulae I, II, III, IV, V and VII and which are extremely preferred of the formulae I, II, III, IV and V. It preferably consists essentially of the compounds and is excellently substantially entirely composed of the compounds. In a preferred embodiment, the liquid crystal medium comprises in each case one or more compounds of each of the equations.

In the present application, the expression of dielectric elaboration stipulates compounds or components in which Δ ε > 3.0, dielectric neutral elaboration of which - And the dielectric negative describes those in which Δε < -1.5. Δε was measured at a frequency of 1 kHz and at 20 °C. The dielectric anisotropy of the corresponding compound is determined from the results of a 10% solution of the corresponding individual compound in the nematic phase host mixture. If the solubility of the corresponding compound in the host mixture is less than 10%, the concentration is reduced to 5%. The capacitance of the test mixture was determined in both cells with vertical alignment and cells with horizontal alignment. The cell thickness of the two types of cells is about 20 μm. The applied voltage is a rectangular wave with a frequency of 1 kHz and the effective value is typically 0.5V to 1.0V, however it is always selected to be below the capacitance threshold of the corresponding test mixture.

The Δε system is defined as (ε _∣∣ -ε _⊥ ), and ε _av. is (ε _∣∣ +2ε _⊥ )/3.

The host mixture mixture ZLI-4792 for dielectrically positive compounds, and the host mixture mixture ZLI-3086 for dielectrically neutral and dielectrically negative compounds, both from Merck KGaA, Germany. The absolute value of the dielectric constant of the compound is determined from the change in the corresponding value of the host mixture after the addition of the compound of interest. This value is extrapolated to the 100% concentration of the compound of interest.

The components having a nematic phase at a measurement temperature of 20 ° C were thus measured, and all other components were treated as a compound.

The expression threshold voltage in the present application refers to the optical threshold and is relative to the relative contrast ratio (V ₁₀ ) of 10%, and the expression saturation voltage refers to optical saturation and is relative to the 90% relative contrast ratio (V ₉₀ ). Except where otherwise explicitly indicated in both cases. The capacitor threshold voltage (V ₀ , also known as the Freedericks threshold (V _Fr )) is used only when explicitly mentioned.

Unless otherwise expressly stated, the scope of the parameters given in this application includes the limit values.

The combination of the different upper and lower limits for each property range produces an additional preferred range.

Unless otherwise expressly stated, the following conditions and definitions are used throughout this application. All concentrations are expressed in weight percent and are relative to the overall mixture, all temperatures are expressed in degrees Celsius and all temperature differences are expressed in degrees. All physical properties are determined according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status Nov. 1997, Merck KGaA, Germany, and the properties at temperatures of 20 ° C are cited unless otherwise explicitly stated. The optical anisotropy (Δn) was measured at a wavelength of 589.3 nm. The dielectric anisotropy (Δε) was measured at a frequency of 1 kHz. The threshold voltage and all other electro-optic properties were determined using a test unit manufactured by Merck KgaA (Germany). The test cell used to determine Δε has a cell thickness of about 20 μm. The electrode system has a circular ITO electrode with an area of 1.13 cm ² and a guard ring. Orientation layer from Nissan Chemicals, Japan of SE-1211 (for a vertical orientation ([epsilon] _||)) and from Japan Synthetic Rubber, Japan the polyimide AL-1054 (for a parallel orientation (ε⊥)). The capacitance was measured using a Solatron 1260 frequency response analyzer using a sine wave of 0.3 V _rms voltage. The light used in electro-optical measurement is white light. This document uses a configuration utilizing a commercially available DSM instrument from Autronic-Melchers, Germany. The characteristic voltage has been measured under vertical observation. The threshold (V ₁₀ ), intermediate gray (V ₅₀ ), and saturated (V ₉₀ ) voltages have been measured at 10%, 50%, and 90% relative contrast ratios, respectively.

The liquid crystal medium of the present invention may contain other additives and a palmitic dopant in a conventional concentration. The total concentration of the other ingredients is in the range of from 0% to 10%, preferably from 0.1% to 6%, based on the total mixture. The concentration of each of the individual compounds used is preferably in the range of from 0.1% to 3%. The concentrations of such and similar additives are not considered in the present application when the values and concentrations of the liquid crystal components and compounds of the liquid crystal medium are provided.

The liquid crystal medium of the present invention is composed of a plurality of compounds, preferably 3 to 30, more preferably 4 to 20, and excellent 4 to 16 compounds. These compounds are mixed in a conventional manner. Generally, the required amount of the compound to be used in a smaller amount is dissolved in the compound used in a larger amount. If the temperature is above the clearing point of the compound used at a higher concentration, it is especially easy to observe the completion of the dissolution process. However, it is also possible to prepare the medium in other conventional ways, for example by using a so-called premix which may be, for example, a similar or eutectic mixture of compounds, or by using a so-called "multi-bottle" system, the ingredients themselves being ready-to-use mixtures.

The liquid crystal medium of the present invention can be modified by adding suitable additives so that it can be used in all known liquid crystal display types such as TN, TN-AMD, ECB-AMD, VAN-AMD, IPS-AMD, FFS. - AMD LCD), or used in composite systems (eg PDLC, NCAP, PN LCD) and especially in ASM-PALCD.

All temperatures, such as the melting point T (C, N) or T (C, S) of the liquid crystal, the transition temperature T (S, N) from the smectic phase (S) to the nematic phase (N), and the clarification point T (N) , I) are quoted in degrees Celsius. All temperature differences are expressed in degrees.

In the present invention and especially in the following examples, the structure of the liquid crystal original compound is represented by an abbreviation (also referred to as an acronym). Among the acronyms, the chemical formulas are abbreviated as follows using the following Tables A to C. All groups C _n H _2n+1 , C _m H _2m+1 and C ₁ H ₂₁₊₁ or C _n H _2n-1 , C _m H _2m-1 and C ₁ H _21-1 all represent a linear alkyl group. Or an alkenyl group preferably represents a 1E-alkenyl group each having n, m and 1 C atom, respectively. Table A lists the codes for the ring units of the core structure of the compound, while Table B shows the linking groups. Table C lists the meaning of the code for the left or right end group. The acronym consists of a code for a loop unit having an optional linking group, a code for the first hyphen and the left-hand end group, and a second hyphen and a right-hand end group. Table D shows the illustrative structure of the compounds along with their corresponding abbreviations.

Where n and m each represent an integer, and three points "..." are used for intervals from other abbreviations in this table.

The following table shows the illustrative structures and their corresponding abbreviations. These structures are shown to illustrate the meaning of the abbreviated rules. Further, it represents a compound which is preferably used.

The following table (Table E) shows illustrative compounds that can be used as stabilizers in the liquid crystal precursor media of the present invention.

In a preferred embodiment of the invention, the liquid crystalline precursor medium comprises one or more compounds selected from the group of compounds of Table E.

The following table (Table F) shows illustrative compounds which are preferably useful as palmitic dopants in the liquid crystal precursor media of the present invention.

In a preferred embodiment of the invention, the liquid crystalline precursor medium comprises one or more compounds selected from the group of compounds of Table F.

The liquid crystal precursor medium of the present invention preferably comprises two or more, preferably four or more compounds selected from the group consisting of the compounds from the above table.

The liquid crystal medium of the present invention preferably comprises

Seven or more, preferably eight or more compounds, preferably three or more, preferably four or more different compounds selected from the group of compounds of Table D.

Instance

The following examples illustrate the invention and are not intended to limit the invention in any way.

However, the physical properties show the nature of the achievable technology and the range of improvements that can be made by those skilled in the art. In particular, a combination of various properties that are better attainable can be clearly defined by those skilled in the art.

A liquid crystal mixture having the composition and properties described in the following table was prepared.

Example 1

This mixture is extremely suitable for displays in TN mode, especially for displays with operating voltages of 3-5 volts. However, it is also extremely suitable for IPS mode displays.

Example 2

This mixture is extremely suitable for displays in TN mode, especially for displays with a drive voltage of 5-7 volts.

Example 3

This mixture is extremely suitable for displays in TN mode, especially for displays with a drive voltage of 5-6 volts.

Claims (12)

A liquid crystal medium characterized by comprising one or more compounds of formula I Wherein R ¹¹ represents an alkyl or alkoxy group having 1 to 7 C atoms, and R ¹² represents H or an alkyl group having 1 to 3 C atoms; and one or more selected from the group consisting of the compounds of the formulae II and III Compound: Wherein R ² and R ³ independently of each other represent an alkyl group having 1 to 7 C atoms, an alkoxy group, a fluoroalkyl group or a fluoroalkoxy group, an alkenyl group having 2 to 7 C atoms, an alkenyloxy group , alkoxyalkyl or fluoroalkenyl, to Representing each other independently each time it appears or L ²¹ , L ²² , L ³¹ and L ³² independently of each other represent H or F, and X ² and X ³ independently of each other represent halogen, haloalkyl or alkoxy having 1-3 C atoms or have 2 or 3 a halogenated alkenyl or alkenyloxy group of a C atom, and Z ³ represents -CH ₂ CH ₂ -, -CF ₂ CF ₂ -, -COO-, trans-CH=CH-, trans-CF=CF-, -CH ₂ O- or a single bond, and m and n represent 0, 1, 2 or 3 independently of each other. The medium of claim 1, wherein system The medium of claim 2, which comprises one or more compounds of formula I wherein R ¹² represents a methyl group. The medium of any one of claims 1 to 3, which comprises one or more compounds of formula IV Wherein R ⁴¹ and R ⁴² independently of each other have the meanings indicated above for R ² of formula II in claim 2, and Independent of each other, and if Appear twice, then these are also independent of each other or Z ⁴¹ and Z ⁴² are independent of each other, and if Z ⁴¹ appears twice, then these also independently represent -CH ₂ CH ₂ -, -COO-, anti-CH=CH-, anti-CF=CF-, - CH ₂ O-, -CF ₂ O-, -C≡C- or a single bond, and P represents 0, 1, or 2. The liquid crystal medium of any one of claims 1 to 3, wherein the total concentration of the compound of formula I in the medium is in the range of from 1% to 30%. The medium of any one of claims 1 to 3, which comprises one or more compounds of formula II. A liquid crystal medium according to any one of claims 1 to 3, which comprises one or more compounds of formula III. The liquid crystal medium according to any one of claims 1 to 3, which comprises one or more dielectric neutral compounds of the formula V Wherein R ⁵¹ and R ⁵² independently of each other have the meanings indicated above for R ² of formula II in claim 2, Representing each other independently or Z ⁵¹ and Z ⁵² are independent of each other, and if Z ⁵¹ occurs twice, then these also independently represent -CH ₂ CH ₂ -, -COO-, anti-CH=CH-, anti-CF=CF-, - CH ₂ O-, -CF ₂ O- or a single bond, and r represents 0, 1, or 2. A liquid crystal display comprising the medium of any one of claims 1 to 8. The display of claim 9 is addressed by an active matrix. A use of a medium according to any one of claims 1 to 8 in a liquid crystal display. A method of preparing a medium according to any one of claims 1 to 8, characterized in that one or more compounds of the formula I as claimed in claim 1 and one or more of the formulas as recited in claim 1 are Compounds of formula II and/or formula III are admixed with one or more compounds as recited in any one of claims 28 and/or one or more other liquid crystal compounds and/or one or more additives.