KR20090055492A - Liquid crystalline medium and liquid crystal display - Google Patents

Abstract

A liquid crystalline medium is provided to ensure suitable proper optical anisotropy (ÝÈn), high ÝÈ epsilon, low viscosity, particularly low rotational viscosity (gamma1), and high contrast ratio in a display. A liquid crystalline medium comprises an A component which is dichroic dye; a B component which is dielectrically positive component; and selectively a C component which is dielectrically neutral component. The A component which is dichroic dye comprises one or more dichromatic dyes. The B component which is dielectrically positive component comprises as least genetically positive one compound selected from the group consisting of the compound of chemical formula 2 and 3. The C component which is dielectrically neutral component comprises one or more compounds which is genetically neutral of chemical formula 4.

Description

LIQUID CRYSTALLINE MEDIUM AND LIQUID CRYSTAL DISPLAY}

The present invention relates to a liquid crystal medium comprising at least one dichroic dye, preferably a dielectric positive nematic medium, and a liquid crystal display comprising said medium, in particular a display addressed by an active matrix, Specifically it relates to a display of type TN, IPS or FFS.

Liquid crystal displays (LCDs) are widely used to show information. LCDs are used for direct view displays as well as projection type displays. The electro-optical schemes used are, for example, twisted nematic (TN)-, super twisted nematic (STN)-, optically compensated bend (OCB)-and birefringent controlled (ECB)-, and various variants thereof, such as vertical. Oriented nematic (VAN), polymer-stabilized vertically oriented nematic (PVA)-and multi-domain vertically oriented nematic (MVA)-schemes as well as other schemes. All of these methods use an electric field substantially perpendicular to each of the substrate and liquid crystal layer. In addition to these methods, the substrate and the liquid crystal layer are substantially applied to each of the substrate and the liquid crystal layer, such as planar alignment switching (abbreviation: IPS) method (as disclosed in DE 40 00 451 and EP 0 588 568) and leakage magnetic field switching (FFS) method. There is also an electro-optical scheme using a horizontal electric field. In particular, these electro-optical approaches are used in LCDs for modern desktop monitors, even displays for TVs and multimedia products. The liquid crystals according to the invention are preferably used for this type of display.

For these displays, there is a need for new liquid crystal media with improved properties. In particular, the contrast ratio should be improved for many product types. Thus, there is a need for a liquid crystal medium having an improved aspect. Their rotational viscosity should be 80 mPa · s or less, preferably 60 mPa · s or less, in particular 55 mPa · s or less. In addition to these variables, the medium should exhibit an adequately wide range of nematic phases, and the appropriate birefringence (Δn) and dielectric anisotropy (Δε) should be high enough to allow reasonably low operation voltage. Preferably, [Delta] [epsilon] should be higher than 3 and very preferably higher than 4, but preferably 15 or less, especially since it may be disadvantageous at least reasonably high resistivity, which is another requirement for active matrix addressing. It should be 12 or less, most preferably in the range of 7-9.

The display according to the invention is preferably addressed by an isometric matrix (active matrix LCD, abbreviated AMD), preferably a thin film transistor (TFT) matrix. However, the liquid crystal of the present invention may be advantageously used in displays having other known addressing means.

Liquid crystal compositions suitable for LCDs, in particular IPS displays, are for example JP 07 181 439 (A), EP 0 667 555, EP 0 673 986, DE 195 09 410, DE 195 28 106, DE 195 28 107, WO 96/23 851 and WO 96/28 521. However, these compositions have significant drawbacks. Most of these, for example, produce disadvantageously low contrast ratios, among other defects, for example when compared to displays that operate in one of the VA schemes, which have recently been vigorously competing for example for TV displays.

Therefore, it is suitable for practical use such as wide nematic phase range, suitable optical anisotropy (Δn), high Δε, low viscosity, especially low rotational viscosity (γ ₁ ), especially high contrast ratio in display, depending on the display mode used. There is a great need for liquid crystal media having properties.

Surprisingly, it has been found in the present invention that a liquid phase medium having a suitable phase range, suitably high Δε and Δn, and a suitably low viscosity, which does not exhibit the drawbacks of the prior art materials or at least exhibits them to a lesser extent, can be obtained. lost.

These improved liquid crystal media according to the present disclosure are at least

(i) at least one dichroic dye, preferably selected from the group of azo-dyes, most preferably selected from compounds of formula 1, preferably at least two, more preferably at least three, most preferably at least three Component A, which is a first dye component comprising two dichroic dyes;

(ii) a component B, which is a genetically positive component, preferably having a dielectric anisotropy greater than 3 and preferably comprising at least one genetically positive compound selected from the group consisting of compounds of Formulas 2 and 3; And

(iii) Optionally, component C, which is a genetically neutral component, preferably comprising essentially one or more genetically neutral compounds of formula

Includes:

Where

내지

는 서로 독립적으로, 또한

및/또는

가 하나보다 많이 존재하는 경우에는 이들

및

전부 서로 독립적으로,

To

Are independent of each other,

And / or

If more than one exists, these

And

All independently of each other,

또는

이며,

or

,

는 또한 if i is 2 or more, the terminal

Is also

일 수 있고, or

Can be,

는 또한 when j is 2 or more, the terminal

Is also

또는

일 수 있으며,

or

Can be,

내지

는 서로 독립적으로, 또한

및/또는

가 하나보다 많이 존재하는 경우에는 이들

및

전부 서로 독립적으로,

또는

이고,Preferably,

To

Are independent of each other,

And / or

If more than one exists, these

And

All independently of each other,

or

ego,

는

일 수 있으며, when m is 2 or more, the terminal

Is

Can be,

는

또는

일 수 있고, when n is 2 or more, the terminal

Is

or

Can be,

내지

중 하나 이상, 가장 바람직하게

내지

중 하나 이상, 가장 바람직하게

은

이며,More preferably,

To

One or more, most preferably

To

One or more, most preferably

silver

,

Z ¹¹ and Z ¹² are independently of each other -N = N-, -OCO- or -COO-,

Preferably Z ¹¹ is -N = N- or -COO-, preferably Z ¹² is -OCO- or a single bond,

R ¹¹ and R ¹² are independently of each other, preferably alkyl, alkoxy, fluorinated alkyl or alkoxy fluoride having 1 to 7 carbon atoms; Preferably alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 carbon atoms; Alkylamineyl, dialkylamineyl, alkylcarbonyl, alkyloxycarbonyl, alkylcarbonyloxy, alkyloxycarbonyloxy or alkylcyclohexylalkyl, preferably R ⁰¹ , R ⁰¹ NH, R ⁰¹ (R ⁰² ) N, R ⁰¹ CO, R ⁰¹ OCO, R ⁰¹ COO or R ⁰¹ OCOO, alkyl, alkenyl or alkylcyclohexylalkyl,

R ⁰¹ and R ⁰² are independently of each other, preferably alkyl, oxaalkyl, fluorinated alkyl or oxaalkyl fluorine each having 1 to 7 carbon atoms; Preferably alkenyl, alkoxyalkyl, fluorinated alkenyl or alkoxyalkyl fluoride each having 2 to 7 carbon atoms; Preferably alkyl, more preferably n-alkyl or iso-alkyl,

i and j are independently of each other 1, 2, 3 or 4, preferably 1, 2 or 3,

(i + j) is preferably 2, 3, 4 or 5, more preferably 2, 3 or 4;

Where

R ² and R ³ are, independently from each other, alkyl, alkoxy, fluorinated alkyl or alkoxy fluoride having 1 to 7 carbon atoms; Alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 carbon atoms; R ² and R ³ are preferably alkyl or alkenyl,

내지

는 서로 독립적으로

To

Independently of each other

또는

, 바람직하게는

or

, Preferably

또는

or

이며,

,

L ²¹ , L ²² , L ³¹ and L ³² are independently of each other H or F, preferably L ²¹ and / or L ³¹ is F,

X ² and X ³ independently of one another are halogen, halogenated alkyl or alkoxy having 1 to 3 carbon atoms, or halogenated alkenyl or alkenyloxy having 2 or 3 carbon atoms, preferably F, Cl,- OCF ₃ or -CF ₃ , most preferably F, Cl or -OCF ₃ ,

Z ³ is _{-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, most preferably -COO-, trans- -CH = CH- or a single bond,

l, m, n and o are each independently 0 or 1;

Where

R ⁴¹ and R ⁴² independently of each other have the meaning given for R ² in Formula 2 above, preferably R ⁴¹ is alkyl and R ⁴² is alkyl or alkoxy, R ⁴¹ is alkenyl and R ⁴² is alkyl,

및

는 서로 독립적으로, 또한

이 2개 존재하는 경우에는 이들도 서로 독립적으로,

And

Are independent of each other,

If these two are present, they are also independent of each other,

이고, 바람직하게

및

중 하나 이상은

이며,or

And preferably

And

One or more of

,

Z ⁴¹ and Z ⁴² are independently of each other and, if two Z ⁴¹ are present, they are also independent of each other: -CH ₂ CH _2- , -COO-, trans- -CH = CH-, trans- -CF = CF—, —CH ₂ O—, —CF ₂ O—, —C≡C— or a single bond, preferably at least one of them is a single bond,

p is 0, 1 or 2, Preferably it is 0 or 1.

Preferably, component A comprises at least one dichroic dye of formula (1), more preferably consists essentially of said compound, even more preferably consists essentially of said compound, most preferably entirely of said compound Is done.

In a preferred embodiment of the invention, component A preferably comprises at least one dichroic dye selected from the group consisting of compounds of the formulas I-1 to I-7, more preferably consists mainly of said compound, more More preferably it consists essentially of said compound and most preferably consists entirely of said compound:

In the above, the variable has the respective meaning given in the above formula (1).

In a preferred embodiment of the invention, component A preferably comprises at least one dichroic dye selected from the group consisting of compounds of the formulas I'-1 to I'-7, more preferably mainly composed of said compounds And even more preferably consists essentially of said compound and most preferably consists entirely of said compound:

In the above, the variable has the respective meaning given in the above formula (1).

Exemplary compounds of formula 1 that are particularly suitable for use as component A are represented by the formula:

Preferably, the concentration of component A in the medium is from 0.1% to 5%, more preferably from 0.2% to 4%, even more preferably from 0.3% to 3%, most preferably from 0.5% to 2%, in particular about 1 Range of%.

In a preferred embodiment, component A consists of a mixture of two or more, preferably three or more, most preferably three compounds. Preferably, the compounds of component A which are components have mutually complementary absorption spectra, i.e. complementary absorption colors, with respect to each other and are preferably mixed in a relative ratio which produces the combined absorption intermediate color of the mixture, ie the black appearance. This means that the absorption is nearly constant in the visible spectral range.

The spectral characteristics of the three compounds I'-1a, I'-4a and I'-4b are as follows.

Dye number I'-1a I'-6a I'-4a I'-5a F593 F503 F355 F357 ME-1107 ME-786 ME-301 Me-540 Absorption Spectrum in CH ₂ Cl ₂ (1 / 100,000) λ _max / nm 621 601 536 426 Δλ _max / nm ± 2 ± 2 ± 2 ± 2 OD ^* 0.620 0.645 0.785 0.520 ΔOD ^* ± 0.020 ± 0.020 ± 0.020 ± 0.020 color blue blue Red Yellow (orange) Dichroic properties Host LC ^§ No.ZLI- 2903 3021-000 2452 DR ^** 16.2 10.9 13.7 13.0 S ^*** 0.83 0.77 0.81 0.80 Note: ^* ): Optical density: OD ODlog ₁₀ (I _i / I _t ) I _i = incident light I _t = transmitted light ^§ ): ZLI-mixture available from Merck KGaA, Germany ^** ): Dichroic ratio of dye at host LC ^*** ): Order parameter of dye at host LC

The medium according to the invention preferably comprises a genetically positive compound having a dielectric anisotropy of greater than 3, more preferably consists mainly of said compound, even more preferably consists essentially of said compound, most Preferably it comprises a genetically positive component, i.e., component B, consisting entirely of said compound.

Preferably, said component, ie, component B, comprises at least one genetically positive compound selected from the group consisting of formulas (2) and (3) and having a dielectric anisotropy greater than 3, more preferably consisting mainly of said compound, and more More preferably it consists essentially of said compound and most preferably consists entirely of said compound.

In a preferred embodiment of the invention, component B comprises at least one genetically positive compound selected from the group consisting of compounds of formulas II-1 to II-3 and having a dielectric anisotropy greater than 3, more preferably It consists mainly of compounds, more preferably consists essentially of said compounds, and most preferably consists entirely of said compounds:

Where

Variable has the respective meanings given in the above Formula 2,

In formula (II-1), variables L ²³ and L ²⁴ are independently H or F for each other and for other variables.

Preferably, component B comprises a compound selected from the group consisting of compounds of formulas II-1 to II-3 wherein L ²¹ and L ²² or L ²³ and L ²⁴ are both F.

In a preferred embodiment, component B comprises a compound selected from the group consisting of compounds of formula II-1 and II-2 wherein L ²¹ , L ²² , L ²³ and L ²⁴ are all F.

Preferably, component B comprises at least one compound of formula (II-1). Preferably, the compound of formula II-1 is selected from the group consisting of compounds of formula II-1a to II-1e:

Wherein the variable has the respective meaning given above.

Preferably, component B comprises a compound selected from the group consisting of compounds of formulas II-1a to II-1e wherein L ²¹ and L ²² or L ²³ and L ²⁴ are both F

In a preferred embodiment, component B comprises a compound selected from the group consisting of compounds of formulas II-1a to II-1e wherein L ²¹ , L ²² , L ²³ and L ²⁴ are all F.

Particularly preferred compounds of formula II-1 are as follows:

Wherein R ² has the meaning given above.

Preferably, component B comprises at least one compound of formula (II-2). Preferably, the compound of formula II-2 is selected from the group consisting of the compounds of formula II-2a to II-2c:

Where

Variables have their respective meanings given above,

Preferably both L ²¹ and L ²² are F.

Preferably, component B comprises at least one compound of formula (II-3). Preferably, the compound of formula II-3 is selected from the group consisting of the following compounds of formula II-3a to II-3d:

Where

Variables have their respective meanings given above,

Preferably both L ²¹ and L ²² are F and L ²³ and L ²⁴ are both H, or L ²¹ , L ²² , L ²³ and L ²⁴ are all F.

Particularly preferred compounds of formula II-3 are as follows:

Wherein R ² has the meaning given above.

In a more preferred embodiment of the invention, component B comprises at least one genetically positive compound selected from the group consisting of compounds of formulas III-1 and III-2 and having a dielectric anisotropy greater than 3, more preferably It consists mainly of compounds, more preferably consists essentially of said compounds, and most preferably consists entirely of said compounds:

Wherein the variables have the respective meanings given in Formula 3 above.

Preferably, component B comprises one or more compounds of Formula III-1. Preferably, the compound of formula III-1 is selected from the group consisting of the compounds of formula III-1a and III-1b:

Where

Variables have their respective meanings provided above,

Variables L ³³ and L ³⁴ are H or F independently of each other and with respect to other variables.

Preferably, component B comprises at least one compound of formula III-2. Preferably, the compound of formula III-2 is selected from the group consisting of the compounds of formula III-2a to III-2h:

Wherein the variables have the respective meanings provided above.

Preferably, component B comprises at least one compound of formula III-1a, preferably selected from the group consisting of compounds of formulas III-1a-1 to III-1a-6:

Wherein R ³ has the meaning provided above.

Preferably, component B comprises at least one compound of formula II-2a, preferably selected from the group consisting of compounds of formula III-2a-1 to III-2a-4:

Wherein R ³ has the meaning provided above.

Preferably, component B is at least one compound of formula II-2b preferably selected from the group consisting of compounds of formula III-2b-1 and III-2b-2, preferably compounds of formula III-2b-2 Includes:

Wherein R ³ has the meaning provided above.

Preferably, component B comprises at least one compound of formula II-2c, preferably selected from the group consisting of compounds of formula III-2c-1 to III-2c-5:

Wherein R ³ has the meaning provided above.

Preferably, component B is selected from the group consisting of compounds of formulas III-2d and III-2e, preferably one compound selected from the group consisting of compounds of formulas III-2d-1 and III-2e-1 Includes the following:

Wherein R ³ has the meaning provided above.

Preferably, component B comprises at least one compound of formula III-2f, preferably selected from the group consisting of compounds of formula III-2f-1 to III-2f-5:

Wherein R ³ has the meaning provided above.

Preferably, component B comprises at least one compound of formula III-2g, preferably selected from the group consisting of compounds of formula III-2g-1 to III-2g-5:

Wherein R ³ has the meaning provided above.

Preferably, component B comprises at least one compound of formula III-2h, preferably selected from the group consisting of compounds of formula III-2h-1 to III-2h-3:

Wherein R ³ has the meaning provided above.

Alternatively or in addition to the compounds of the formulas III-1 and / or III-2, the media according to the invention may comprise at least one compound of the formula III-3, preferably at least one compound of the formula III-3a Can:

Wherein the variables have the respective meanings provided in Formula 3 above;

Wherein R ³ has the meaning provided above.

Preferably, the liquid crystal medium according to the invention comprises a dielectric neutral component, ie a C component. The component has a dielectric anisotropy in the range of -1.5 to 3. Preferably, it comprises a genetically neutral compound having a dielectric anisotropy in the range of -1.5 to 3, preferably consisting mainly of said compound, more preferably consisting essentially of said compound, particularly preferably said Made entirely of compounds. Preferably, said component, ie, component C, comprises at least one genetically neutral compound of formula 4 having a dielectric anisotropy in the range of -1.5 to 3, more preferably mainly composed of said compound, more preferably Consisting essentially of the compound, particularly preferably entirely of the compound.

Preferably, the dielectric neutral component, ie, the C component, comprises at least one compound selected from the group consisting of the compounds of formulas IV-1 to IV-5:

Where

R ⁴¹ and R ⁴² have the meanings provided for in Formula 4,

In formulas IV-1, IV-4 and IV-5, R ⁴¹ is preferably alkyl or alkenyl, preferably alkenyl, R ⁴² is preferably alkyl or alkenyl, preferably alkyl,

In formula (IV-2), R ⁴¹ and R ⁴² are preferably alkyl,

In formula IV-3, R ⁴¹ is preferably alkyl or alkenyl, preferably alkyl, and R ⁴² is preferably alkyl or alkoxy, preferably alkoxy.

In a preferred embodiment, the C component is preferably at least one compound of formula IV-4, more preferably a compound of its respective subformulae CCP-Vn and / or CCP-nV-m and / or CCP-Vn-m, More preferably compounds of formula CCP-Vn and / or CCP-V2-n, most preferably compounds selected from the group consisting of compounds of formula CCP-V-1 and CCP-V2-1. Definitions of the abbreviations (acronyms) are provided in Table 2.

Preferably, the genetic neutral component, ie, the C component, is at least one compound selected from the group consisting of compounds of formulas IV-1, IV-3, IV-4 and IV-5, preferably at least one compound of formula IV-1 At least one compound selected from the group consisting of the compounds of Formulas IV-3 and IV-4, preferably at least one compound of each of Formulas IV-1, IV-3 and IV-4, most preferably Formula IV-1 And at least one compound of each of IV-3, IV-4 and IV-5.

In a more preferred embodiment of the invention, which may be the same or different from the above-mentioned embodiments, the liquid crystal mixture according to the invention is a compound of formulas IV-1 to IV-5 as shown above, and optionally of formula IV-6 To a compound of formula 4 selected from the group consisting of compounds of IV-13, preferably consisting mainly of said compound, most preferably comprising a C component consisting entirely of said compound:

Where

R ⁴¹ and R ⁴² independently of each other are alkyl, alkoxy, alkyl fluoride or alkoxy fluoride having 1 to 7 carbon atoms; Alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl of 2 to 7 carbon atoms,

L ⁴ is H or F.

Alternatively or in addition to the compounds of Formulas 2 and / or 3, the media according to the invention may comprise one or more genetically positive compounds of the following Formula 5:

Where

R ⁵ is alkyl, alkoxy, alkyl fluoride or alkoxy fluoride having 1 to 7 carbon atoms; Alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl of 2 to 7 carbon atoms, preferably alkyl or alkenyl,

내지

는 서로 독립적으로

To

Independently of each other

이고,or

ego,

L ⁵¹ and L ⁵² are independently of each other H or F, preferably L ⁵¹ is F,

X ⁵ is halogen, halogenated alkyl or alkoxy of 1 to 3 carbon atoms, or halogenated alkenyl or alkenyloxy of 2 or 3 carbon atoms, preferably F, Cl, -OCF ₃ or -CF ₃ , most preferred Preferably F, Cl or -OCF ₃ ,

Z ⁵ is -CH ₂ CH _2- , -CF ₂ CF _2- , -COO-, trans -CH = CH-, trans -CF = CF- or -CH ₂ O-, preferably -CH ₂ CH _2- , -COO- or trans -CH = CH-, most preferably -COO- or -CH ₂ CH _2- ,

q is 0 or 1;

Preferably, the medium according to the invention preferably comprises at least one compound of formula 5 selected from the group consisting of compounds of formulas V-1 and V-2:

Where

Variables have their respective meanings provided above,

Variables L ⁵³ and L ⁵⁴ are H or F independently of each other and other variables,

Preferably Z ⁵ is -CH ₂ CH _2- .

Preferably, the compound of formula V-1 is selected from the group consisting of compounds of formulas V-1a and V-1b:

Wherein R ⁵ has the meaning provided above.

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

Wherein R ⁵ has the meaning provided above.

Preferably, the liquid crystal medium according to the invention comprises a D component which is an additional dielectric neutral component. The component has a dielectric anisotropy in the range of -1.5 to 3. Preferably, it comprises a genetically neutral compound having a dielectric anisotropy in the range of -1.5 to 3, preferably consisting mainly of said compound, more preferably consisting essentially of said compound, particularly preferably said Made entirely of compounds. Preferably, said component, ie, component D, comprises at least one genetically neutral compound of formula 6 having a dielectric anisotropy in the range of -1.5 to 3, more preferably mainly comprising said compound, more preferably Consisting essentially of said compound, particularly preferably consisting entirely of said compound:

Where

R ⁶¹ and R ⁶² independently of each other have the meaning provided in R ² of Formula 2, preferably R ⁶¹ is alkyl, R ⁶² is alkyl or alkenyl,

는, 상기 잔기가 2개 존재하는 경우에는 각 경우에 서로 독립적으로,

When two residues are present, independently of each other in each case,

또는

이고, 바람직하게 하나 이상의

는

이며,

or

And preferably at least one

Is

,

Z ⁶¹ and Z ⁶² are independent of each other and, if two Z ⁶¹ are present, they are also independent of each other: -CH ₂ CH _2- , -COO-, trans -CH = CH-, trans- CF = CF—, —CH ₂ O—, —CF ₂ O— or a single bond, preferably at least one of them is a single bond,

r is 0, 1 or 2, Preferably it is 0 or 1.

Preferably, the additional genetic neutral component, ie, the D component, comprises at least one compound selected from the group consisting of compounds of the following formulas VI-1 and VI-2:

Where

R ⁶¹ and R ⁶² each have the meaning given in Formula 6, R ⁶¹ is preferably alkyl,

In formula (VI-1), R ⁶² is preferably alkenyl, preferably — (CH ₂ ) ₂ —CH═CH—CH ₃ ,

In formula (VI-2), R ⁶² is preferably alkyl.

Preferably, the additional genetic neutral component, ie, the D component, comprises at least one compound selected from the group consisting of compounds of the formulas VI-1 and VI-2, wherein preferably R ⁶¹ is n-alkyl, and formula VI R ⁶² in -1 is preferably alkenyl, and R ⁶² in formula VI-2 is preferably n-alkyl.

In a preferred embodiment, component D preferably comprises at least one compound of formula VI-1, more preferably a compound of subformulae PP-n-2Vm, more preferably a compound of formula PP-1-2V1. Definitions of these abbreviations (acronyms) are provided in Table 2.

In a preferred embodiment, the component D is preferably at least one compound of the formula VI-2, more preferably a compound of its subformulae PGP-nm, more preferably a compound of its subformulae PGP-3-m, more preferably Includes compounds selected from formulas PGP-3-2, PGP-3-3, PGP-3-4, and PGP-3-5. Definitions of these abbreviations (acronyms) are provided in Table 2.

Preferably, the liquid crystal mixture according to the invention contains at least one further component in addition to the A and B components. The third component may be one of C and D components, and the third component present is preferably a C component.

Clearly, the mixtures according to the invention may also contain all four of A, B, C and D components.

Optionally, the media of the present invention may comprise additional compounds such as, for example, chiral dopants and / or stabilizers. Such compounds are known to the skilled person. These compounds constitute the E component.

Preferably, the liquid crystal medium according to the invention comprises A to E components, preferably A to D components, most preferably A to C components, in particular of formulas 1 to 6, preferably of formulas 1 to 5, most preferably It comprises a compound selected from the group consisting of compounds of the formulas (1) to (4), more preferably consists mainly of the material, more preferably consists essentially of the material, most preferably consists entirely of the material.

The term "comprising" herein with reference to a composition means that the units mentioned, such as the medium or component, contain at least 10%, most preferably at least 20% of the components or components or compounds or compounds in question. I mean.

The term “consisting mainly of” herein means that the mentioned units contain at least 55%, preferably at least 60% and most preferably at least 70% of the components or components or compounds or compounds of interest.

The term "consisting essentially of" herein means that the mentioned units contain at least 80%, preferably at least 90% and most preferably at least 95% of the components or components or compounds or compounds of interest.

As used herein, the term “consisting entirely” means that the mentioned units contain at least 98%, preferably at least 99% and most preferably at least 100.0% of the components or components or compounds or compounds.

In addition, other mesogenic compounds not explicitly mentioned above may optionally also be used in the medium according to the invention. Such compounds are known to those skilled in the art.

The liquid crystal medium according to the invention is characterized by a clearing point of at least 70 ° C, preferably at least 75 ° C.

Δn at 589 nm (Na ^D ) and 20 ° C. of the liquid crystal medium according to the invention is preferably in the range of 0.060 to 0.135, more preferably in the range of 0.070 to 0.130 and most preferably in the range of 0.080 to 0.122.

[Delta] [epsilon] at 1 GPa and 20 DEG C of the liquid crystal medium according to the present invention is preferably 3 or more, more preferably 4 or more, most preferably 6 or more. In particular, Δε is 12 or less.

Preferably, the nematic phase of the medium according to the invention is at least 0 ° C. to 70 ° C. or more, more preferably at least −20 ° C. to 70 ° C. or more, most preferably at least −30 ° C. to 75 ° C. or more, in particular At least -40 ° C or lower and 75 ° C or higher.

In a first preferred embodiment of the present invention, Δn of the liquid crystal medium is in the range of 0.090 to 0.125, more preferably in the range of 0.095 to 0.120, most preferably in the range of 0.100 to 0.115, while Δε is preferably in the range of 3 to 12, Preferably it is the range of 10 or less.

In a second preferred embodiment of the present invention, Δn of the liquid crystal medium is in the range of 0.085 to 0.130, more preferably in the range of 0.090 to 0.125, most preferably in the range of 0.095 to 0.120, while Δε is preferably at least 4, more preferably. Preferably at least 6, even more preferably at least 8.0 and most preferably in the range from 8.0 to 10.0.

In this embodiment, preferably the nematic phase of the medium according to the invention is at least -20 ° C or less and 70 ° C or more, more preferably at least -20 ° C or less and 70 ° C or more and most preferably at least -30 ° C or less. Or more, in particular, at least -40 ° C or less and 70 ° C or more.

In a third preferred embodiment of the invention, Δn of the liquid crystal medium is in the range of 0.070 to 0.120, more preferably in the range of 0.075 to 0.115, most preferably in the range of 0.080 to 0.110, while Δε is preferably at least 4.0, more preferably Preferably in the range from 4.0 to 14.0, most preferably in the range from 4.0 to 6.0, or particularly preferably in the range from 6.0 to 11.0.

In this embodiment, the nematic phase of the medium according to the invention is preferably at least -20 ° C or less and 75 ° C or more, more preferably at least -30 ° C or less and 70 ° C or more and most preferably at least -30 ° C or less. At least < RTI ID = 0.0 >

Component B is preferably used at a concentration of 5% to 60%, more preferably 10% to 55%, more preferably 15% to 50%, most preferably 20% to 45% in the total mixture.

Component C is preferably used at a concentration of 0% to 70%, more preferably 10% to 60%, more preferably 20% to 50%, most preferably 15% to 50% in the total mixture.

The component D is preferably used at a concentration of 0% to 50%, preferably 1% to 40%, more preferably 5% to 30% and most preferably 10% to 20% in the total mixture.

The component E is preferably used at a concentration of 0% to 30%, preferably 0% to 15%, most preferably 1% to 10% in the total mixture.

Optionally, the medium according to the invention may comprise further liquid crystal compounds to adjust the physical properties. Such compounds are known to the skilled person. The concentration of the compound in the medium according to the invention is preferably 0% to 30%, more preferably 0.1% to 20% and most preferably 1% to 15%.

In the first preferred embodiment of the invention described above, the component D is preferably used at a concentration of 5% to 40%, preferably 10% to 35%, most preferably 10% to 30% in the total mixture.

In this preferred embodiment, the medium preferably comprises at least one compound of formula (6), most preferably compound of formula (VI-2).

In particular, in the second preferred embodiment of the invention described above, the C component is preferably at least one compound of the formula (4), more preferably a compound of the formula (IV-1), more preferably each of its subformulae CC-nV and A compound of CC-n-Vm, more preferably a compound of formula CC-n-V1 and / or CC-nV, most preferably a compound of formula CC-3-V, CC-4-V, CC-5- Compounds selected from the group consisting of compounds of V and CC-3-V1. Definitions of these abbreviations (acronyms) are provided in Table 2.

Preferably, the liquid crystal medium contains at least one compound of formulas 1, 2, 3, 4, 5 and 6, preferably of formulas 1, 2, 3, 4 and 5, preferably consisting mainly of said compound and , Most preferably the A, B, C and D components entirely composed of the compound, preferably 50% to 100%, more preferably 70% to 100%, most preferably all of the A, B and C components 80% to 100%, especially 90% to 100%.

As used herein, the term "genetically positive" means a compound or component with Δε> 3.0, and "genetically neutral" means a compound or component with -1.5≤Δε≤3.0, and "genetically negative" is Δ It means a compound or component having ε <-1.5. Δε is determined at 1 kHz and 20 ° C. The dielectric anisotropy of each compound is determined from the result of 10% solution of each individual compound in the nematic host mixture. If the solubility of each compound in the host mixture is less than 10%, the concentration is reduced to 5%. The capacity of the test mixture is determined in both cells with vertical and parallel orientations. The cell gap of both cell types is about 20 μm. The applied voltage is a rectangular wave with a frequency of 1 Hz and is typically a square root mean value of 0.5 V to 1.0 V, but should always be chosen to be below the capacity threshold of each test mixture.

Δε is defined as (ε _∥ −ε _⊥ ), and ε _av. Is defined as (ε _∥ + 2ε _⊥ ) / 3.

For the genetically positive compound the mixture ZLI-4792 and for the genetically neutral compound and the genetically negative compound the mixture ZLI-3086 (both from Merck Kagaa Germany) are used as host mixtures, respectively. The permittivity of a compound is determined from the change in each value of the host mixture when the compound is added. The value is estimated by extrapolating the concentration of the compound to 100%.

The component having the nematic phase at 20 ° C. measurement temperature is measured as it is, and the others are treated like compounds.

Unless expressly stated otherwise, the term threshold voltage herein refers to the optical threshold, given for 10% relative contrast (V ₁₀ ), and the term saturation voltage refers to optical saturation, 90% relative Given for contrast (V ₉₀ ). The capacitance threshold voltage, V ₀ , also referred to as the Fredericks-threshold V _Fr , is used only where explicitly stated.

The range of variables provided herein is all values, including limit values, unless expressly stated otherwise.

Unless expressly stated otherwise throughout this application, all concentrations are given in mass percent, are for each complete mixture, all temperatures are given in degrees Celsius, and all temperature differences are degrees Celsius. All physical properties were determined and determined based on Merck Liquid Crystals, Physical Properties of Liquid Crystals, November 1997 edition, Merck Kagaa, Germany, and expressly otherwise Unless stated, it is given for a temperature of 20 ° C. Optical anisotropy (Δn) is determined at a wavelength of 589.3 nm. The dielectric anisotropy (Δε) is determined at the 1 kHz frequency. All other electro-optical properties as well as the threshold voltage were determined using test cells made by Merck Kagaa, Germany. The test cell for determining Δε had a cell gap of about 20 μm. The electrode was a circular ITO electrode with a 1.13 cm 2 area and guard ring. The alignment layer was lecithin for homeotropic orientation (ε _∥ ) and polyimide AL-1054 from Japan Synthetic Rubber for homogeneous orientation (ε _⊥ ). Capacitance was determined using a Solatron 1260 frequency response analyzer using a sine wave at 0.3V _rms voltage. The light used for the electro-optical measurement was white light. The device used was a device commercially available from Autronic Melchers, Germany. The characteristic voltage was determined under vertical observation. Threshold (V ₁₀ ) -mid-grey (V ₅₀ ) -saturated (V ₉₀ ) voltages were determined for 10%, 50% and 90% relative contrast, respectively.

The liquid crystal medium according to the present invention may contain additional additives and chiral dopants in conventional concentrations. The total concentration of these additional components ranges from 0% to 10%, preferably 0.1% to 6%, based on the total mixture. The concentrations of the individual compounds used are each preferably in the range of 0.1% to 3%. The concentrations of these and similar additives are not considered in the values and ranges of the concentrations of the liquid crystal components and compounds of the liquid crystal medium herein. This also applies to the concentrations of the dichroic dyes used in the mixture, which are not taken into account when the concentration of each of the components of the host mixture, the compound, is specified. The concentration of each additive is always provided for the final doped mixture.

The liquid crystal medium according to the invention consists of several compounds, preferably 3 to 30, more preferably 4 to 20 and most preferably 4 to 16 compounds. These compounds are mixed in a conventional manner. In general, the required amount of the compound used in smaller amounts is dissolved in the compound used in higher amounts. It is particularly easy to observe that the dissolution process is complete when the temperature is higher than the clearing point of the compound used at the higher concentration. However, so-called multi-bottle-systems can be used, for example, using so-called pre-mixtures which can be homogeneous or eutectic mixtures of compounds or allowing the components to use the mixture itself immediately. The medium may also be prepared by other conventional methods used.

By the addition of suitable additives the liquid crystal medium according to the invention is used in all known types of liquid crystal displays using the liquid crystal medium itself, in particular PDLC, such as TN-, TN-AMD, ECB-AMD, VAN-AMD, IPS and OCB LCD. It can be modified to be used in complex systems such as NCAP, PN LCD, especially in ASM-PA LCD.

The melting point T (C, N) of the liquid crystal, the transition T (S, N) from the smectic (S) onto the nematic (N) and the clearing point T (N, I) are given in degrees Celsius.

In this application, and in particular in the examples below, the structure of the liquid crystal compound is denoted by the abbreviation, which is also referred to as “acronym”. It is easy to understand according to the three tables 1 to 3 to modify the abbreviations to the corresponding structural formulas.

All of the C _n H _{2n + 1} , C _m H _{2m + 1} and C _l H _{2l + 1} groups are straight chain alkyl groups having n, m and l carbon atoms, respectively, and —CH═CH— is preferably each trans— E-vinylene.

Table 1 lists the symbols used for the ring elements, Table 2 lists the symbols for the linking groups, and Table 3 lists the symbols for the left and right end groups of the molecule.

Table 4 lists exemplary molecular structures with each code.

In the table, n and m are each an integer, and "…" represents a space for another sign of the table.

Preferably, the liquid crystal medium according to the invention comprises at least one compound selected from the group consisting of compounds of the formulas in the following table in addition to the compound (s) of the formula (1).

Table 5 lists chiral dopants which are preferably used in the liquid crystal medium according to the present invention.

In a preferred embodiment of the invention, the medium according to the invention comprises at least one compound selected from the group consisting of the compounds of Table 5.

Table 6 lists stabilizers which are preferably used in the liquid crystal medium according to the present invention.

"N" in the above means an integer of 1 to 12.

In a preferred embodiment of the invention, the medium according to the invention comprises at least one compound selected from the group consisting of the compounds of Table 6.

The liquid crystal medium according to the invention is preferably selected from the group consisting of at least 4 compounds, preferably at least 6 compounds, preferably from compounds of the formula of Table 4 and preferably from At least 7, preferably at least 8, compounds having at least 2 different formulas.

The liquid crystal medium according to the invention is preferably selected from the group consisting of the compounds of Table 4 and preferably at least 3 compounds, more preferably at least 4 compounds, more preferably at least 5 compounds, preferably having different formulas Preferably it contains at least 7 compounds, more preferably at least 8 compounds, selected from the group consisting of the compounds of Table 4 and preferably having different formulas.

 Table 7 lists the dichroic dyes which are preferably used in the liquid crystal medium according to the present invention.

In the above,

l, m and n are each independently, preferably an integer in the range of 1 to 7, more preferably in the range of 1 to 5.

With the present invention, substantial necessities such as wide nematic phase range, suitable optical anisotropy (Δn), high Δε, low viscosity, in particular low rotational viscosity (γ ₁ ), especially high contrast ratios in the display, depending on the display mode used Liquid crystal media having properties suitable for the application can be obtained.

Example

The examples provided below are illustrative without limiting the invention in any way. However, physical properties and compositions show those skilled in the art what properties can be obtained and to what extent can be modified. Therefore, the combination of various properties which can be obtained particularly preferably can be well defined by those skilled in the art.

Comparative Example 1

A liquid crystal mixture (A-0) having the composition and properties provided in the table below was obtained.

The mixture is already well suited for displays operating in an IPS manner to quickly switch TVs. The properties are provided in Table 10 below for comparison.

Examples 1.1 to 1.3

To the liquid crystal mixture A-O was added a mixture of three dichroic dyes (MD1) having the following composition.

Dye Concentration in Host Subject Single dye Dye mixture designation DR1 DY1 DB1 MD1 Dye chemical formula I'-4a I'-5a I'-1a dyes Concentration / relative mass unit DR1 100 0 0 31 DY1 0 100 0 60 DB1 0 0 100 70 Σ 100 100 100 161 color Red yellow blue black

In a series of three consecutive studies, 0.1%, 0.3% and 0.5% of the dye mixture MD1, respectively, was added to the liquid crystal mixture A-0 to obtain three mixtures A-1 to A-3. These three mixtures were studied with the host mixture (A-O) for their performance in IPS test cells. The results are shown in the table below.

result Example compare 1.1 1.2 1.3 mixture A-O A-1 A-2 A-3 Concentration (MD1) /% 0 0.1 0.3 0.5 CR 167 289 585 622 CR / CR (A-O) /% 100 173 351 372 Note: CR: Contrast Ratio

The results clearly show the superiority of the medium according to the invention. This indicates that when 0.5% of the black dye mixture is used (see Example 1.3), the contrast ratio of the display is increased by 3.7 times compared to the display using only the pure host liquid crystal mixture.

Claims (10)

Component A, which is a dichroic dye component comprising at least one dichroic dye, Preferably a B component which is a genetically positive component comprising at least one dielectrically positive compound selected from the group consisting of the compounds of Formulas 2 and 3, and Optionally, a C component that is a genetically neutral component that includes one or more genetically neutral compounds of Formula 4 Liquid crystal medium comprising: Formula 2

Formula 3

Where R ² and R ³ are independently of each other alkyl, alkoxy, alkyl fluoride or alkoxy fluoride having 1 to 7 carbon atoms; Alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl of 2 to 7 carbon atoms,

To

Independently of each other

or

, L ²¹ , L ²² , L ³¹ and L ³² are independently of each other H or F, X ² and X ³ independently of one another are halogen, halogenated alkyl or alkoxy of 1 to 3 carbon atoms, or halogenated alkenyl or alkenyloxy of 2 or 3 carbon atoms, Z ³ is -CH ₂ CH _2- , -CF ₂ CF _2- , -COO-, trans --CH = CH-, trans --CF = CF-, -CH ₂ O- or a single bond, l, m, n and o are each independently 0 or 1; Formula 4

Where R ⁴¹ and R ⁴² independently of each other have the meaning given in R ² of Formula 2,

And

Are independent of each other,

If these two are present, they are also independent of each other,

or

, Z ⁴¹ and Z ⁴² are independently of each other and, if two Z ⁴¹ are present, they are also independent of each other: -CH ₂ CH _2- , -COO-, trans -CH = CH-, trans- CF = CF-, -CH ₂ O-, -CF ₂ O-, -C≡C- or a single bond, p is 0, 1 or 2. The method of claim 1, Liquid crystal medium, characterized in that the concentration of the component A in the medium ranges from 0.1% to 5%. The method according to claim 1 or 2, A liquid crystalline medium, characterized in that component A comprises at least one compound of the formula Formula 1

Where

To

Are independent of each other,

And / or

If more than one exists, these

And

All independently of each other,

or

ego, the terminal if i is 2 or more

Is also

or

Can be, the terminal if j is 2 or more

Is also

or

Can be, Z ¹¹ and Z ¹² are independently of each other -N = N-, -OCO- or -COO-, R ¹¹ and R ¹² are independently of each other alkyl, alkoxy, fluorinated alkyl or alkoxy fluoride, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl, alkylamineyl, dialkylamineyl, alkylcarbonyl, alkyloxycarbonyl , Alkylcarbonyloxy, alkyloxycarbonyloxy or alkylcyclohexylalkyl, i and j are 1, 2, 3 or 4 independently of each other. The method according to any one of claims 1 to 3, Liquid crystal medium, characterized in that it comprises at least one compound of formula (2) as defined in claim 1. The method according to any one of claims 1 to 4, Liquid crystal medium, characterized in that it comprises at least one compound of the formula (3) as defined in claim 1. The method according to any one of claims 1 to 5, A liquid crystal medium comprising at least one genetically neutral compound of formula 4 as defined in claim 1. The method according to any one of claims 1 to 6, A liquid crystal medium comprising a component D comprising at least one compound of the formula: Formula 6

Where R ⁶¹ and R ⁶² independently of each other have the meaning given for R ² in Formula 2 in claim 1,

Are independent of each other in each case,

or

, Z ⁶¹ and Z ⁶² are independent of each other and, if two Z ⁶¹ are present, they are also independent of each other: -CH ₂ CH _2- , -COO-, trans -CH = CH-, trans- CF = CF-, -CH ₂ O-, -CF ₂ O-, -C≡C- or a single bond, r is 0, 1 or 2. A liquid crystal display comprising the liquid crystal medium according to claim 1. The method of claim 8, A liquid crystal display characterized by being addressed by an active matrix. Use of a liquid crystal medium according to any one of claims 1 to 7 in a liquid crystal display.