KR20190076882A - Liquid crystalline medium and liquid crystal display - Google Patents

Abstract

The present invention relates to a nematic medium (the nematic medium randomly includes at least one chiral dopant), which comprises one or more compounds of chemical formula I, and one or more compounds selected from the group of chemical formula G, and has a positive dielectric constant, and to a liquid crystal display including the same, in particular a TN-display, an active matrix display and a reflective cholesteric display. In the chemical formulas, parameters are as defined in claim 1.

Description

[0001] LIQUID CRYSTALLINE MEDIUM AND LIQUID CRYSTAL DISPLAY [0002]

The present invention relates to a liquid crystal composition comprising a compound having at least one positive permittivity and a compound having at least one neutral permittivity and preferably comprising at least one chiral dopant and preferably encapsulated in a polymer matrix or polymer stabilized in a polymeric medium , Preferably a nematic medium with a positive dielectric constant, a liquid crystal display comprising said medium, in particular a display which operates in a reflective mode, for example as a cell for a cholesteric mirror, and is preferably addressed by an active matrix, And is particularly well suited for cholesteric reflective liquid crystals.

Liquid crystal displays (LCDs) are widely used to display information. LCDs are used not only for direct view displays but also for projection displays. The all-optical mode used in most displays is still a twisted nematic (TN) mode and various variations thereof. (STN) mode and more recently, optically compensated bend (OCB) mode and electronically controlled birefringence (ECB) mode and various variations thereof, such as vertically aligned nematic ), Patterned ITO vertically aligned nematic (PVA) modes and polymer stabilized and vertically aligned nematic (PSVA) modes and multi-domain vertically aligned nematic (MVA) modes as well as other modes are increasingly being used. All these modes use an electric field that is substantially perpendicular to the substrate or liquid crystal layer. In addition to these modes, an all-optical mode using an electric field that is substantially parallel to the substrate or liquid crystal layer, such as an in-plane switching (abbreviated IPS) mode (see, for example, German Patent No. 40 00 451 and European Patent No. 0 588 568 ) And fringe field switching (FFS) modes. In particular, an all-optical mode with good viewing angle characteristics and improved response time, mentioned later in these, is being increasingly used in displays for LCDs for the latest desktop monitors, and even for TVs and multimedia products, and thus competing with TN-LCDs.

The liquid crystal LC according to the present invention is preferably used in an improved LCD using cholesteric liquid crystals (also known as chiral nematic liquid crystals), especially those with high dielectric anisotropy and short helical pitch for the latest products. This is particularly useful for operating in a reflected mode because a cholesteric liquid crystal with an appropriate cholesteric pitch can be colored by selectively reflecting light and avoiding the use of a color filter on the LCD It is because.

The cholesteric liquid crystal may be encapsulated in a polymer matrix, for example, as PDLC or NCAP.

In such applications, a novel liquid crystal medium with improved properties is needed. Therefore, there is a need for a liquid crystal medium with improved behavior. Its rotational viscosity should be as low as possible. The medium has, in addition to its parameters, a suitable birefringence (n) in a suitably wide range of nematic phases, preferably in the range from 0.100 to 0.200, preferably in the range from 0.110 to 0.190, more preferably in the range from 0.120 to 0.180, Should exhibit a suitably high dielectric anisotropy (DELTA epsilon). It should be high enough to allow a significantly lower operating voltage. Preferably, DELTA epsilon should be greater than or equal to 50, preferably greater than or equal to 55, so as to allow the use of readily accessible drivers with suitably low operating voltages. However, since? Is detrimental to the at least some high specific resistance (which again is another requirement, especially in the case of active matrix addressing),? Should preferably be less than 75, especially less than 70. Most preferably, DELTA epsilon must range from 52 to 68. [

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

Liquid crystal compositions suitable for LCDs, especially TN-displays, are already well known. However, these compositions have significant drawbacks. Most of the above compositions cause, among other defects, a long response time and / or an excessively low contrast ratio, which is disadvantageous for many applications. It also has inadequate reliability and stability for exposure to radiation, especially when one or more of these stressors are combined with each other, most particularly by heat, moisture, or light (especially UV).

A liquid crystal medium for a cholesteric liquid crystal device is known, for example, from International Patent Application Publication No. WO 2010/022891 Al. In this document, the medium is a compound of formula

And polymeric precursors, e.

And

.

The latter is used to increase the bandwidth of cholesteric reflections of the material.

However, this medium, on the one hand, is characterized by a too low or too low settling Δn for many practical applications, and on the other hand a switchable CLC mode which is too high for many practical purposes, Has a considerable drawback because it features a somewhat lower value of DELTA epsilon which causes an unacceptably high operating voltage ( _Vop ).

In particular, another essential drawback of the prior art media with relatively high? Values (which result in desirable low operating voltages) is the nematic or cholesteric phase temperature range, which is particularly stable at low temperatures, It is not limited to these low ends. If the liquid crystalline medium exhibits a higher crystallization point, for example greater than 90 ° C or greater than 100 ° C, its deep temperature stability is often insufficient.

In addition, undesirable changes in the central wavelength location of selective reflection and / or chirality (i.e., cholesteric pitch) as a function of temperature negatively affect the performance of the media according to the state of the art.

These adverse conditions are maintained, albeit to a lesser extent, even in the case of the materials of European patent applications EP 16198490.1 and EP 17208624.1, which have not yet been published. In particular, the value of Δε realized in EP 16198490.1 is already quite high, while Δn is also quite high.

Thus, according to the display mode used, improve the characteristics suitable for practical use (e.g., a wide nematic phase range, a suitable optical anisotropy (Δn), a high Δε value, a low viscosity, especially at low low rotational viscosity (γ _1), the display A high response time, and a high reliability).

Surprisingly, it has been found that it is possible to achieve liquid crystal media which do not exhibit or at least to a lesser extent exhibit the disadvantages of the prior art materials, and which have a suitable phase range, suitably high values of DELTA epsilon and DELTA n and suitably low viscosities.

The improved liquid crystal medium according to the present invention comprises, at least,

One, two or more of the following compounds of formula I:

(Wherein,

R ¹ is preferably alkyl having 1 to 7 carbon atoms, alkoxy, fluorinated alkyl or fluorinated alkoxy, alkenyl, alkenyloxy, alkoxyalkyl, fluorinated alkenyl or fluorinated alkenyloxy, preferably alkyl Or alkoxyalkyl, most preferably n-alkyl,

은

이고,

silver

ego,

L ¹¹ and L ¹² independently of one another are H or F, preferably L ¹¹ is F, L ¹² is H,

X < ^{1 >} is CN or NCS, preferably CN,

i is 0 or 1, preferably 0, and

Two, or more compounds of the formula G < RTI ID = 0.0 >: < / RTI &

(Wherein,

R ^G is alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 carbon atoms, alkenyl having 2 to 7 carbon atoms, alkenyloxy, alkoxyalkyl or alkenyl, and R ^G is preferably alkyl or Alkenyl,

Preferably R < ² > is alkyl or alkenyl,

는 서로 독립적으로

Lt; / RTI >

,

,

이고,Preferably,

ego,

L ^G1 and L ^G2 are independently of each other H or F, preferably L ^G1 and / or L ^G2 is F, preferably L ^G1 and L ^G2 are both F,

X ^G is CN or NCS, preferably CN.

.

The medium according to the invention is optionally, preferably essentially,

- one, two or more polymerizable compounds,

2, II-3 and III, preferably having a dielectric anisotropy of more than 3, and preferably having a positive dielectric constant, selected from the group of compounds of the formulas II-1, II- Further compounds, preferably one or more compounds of each of the above formulas:

(Wherein,

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

중 적어도 하나,

Lt; / RTI >

중 적어도 하나,Preferably,

Lt; / RTI >

는Most preferably,

The

이고,

ego,

중 나머지는, 서로 독립적으로,

Lt; / RTI > independently of one another,

,

,

Preferably,

ego,

L ²¹ and L ²² independently of one another are H or F, preferably L ²¹ and / or L ²² are F, preferably L ²¹ and L ²² are both F,

X ² 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 , F, Cl or -OCF ₃ )

(Wherein,

R ² and R ³ are, independently of each other, alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 carbon atoms, alkenyl having 2 to 7 carbon atoms, alkenyloxy, alkoxyalkyl or fluorinated alkenyl, Lt; / RTI > is alkyl or alkenyl,

는, 서로 독립적으로,

Independently of one another,

이고,

ego,

는, 서로 독립적으로,

Independently of one another,

이고,

ego,

L ²¹ , L ²² , L ³¹ and L ³² independently of one another are 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 selected from the group consisting of -CH ₂ CH ₂ -, -CF ₂ CF ₂ -, -COO-, trans-CH═CH-, trans-CF═CF-, -CH ₂ O- or a single bond, 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 independently of each other 0 or 1).

And optionally,

- at least one compound of the formula T:

In this formula,

R ^T1 and R ^T2 are independently from each other alkyl, alkoxy, alkenyl, alkenyloxy, alkoxyalkyl, alkenyloxy, or alternatively, R ^T2 may be X ^T ,

X ^T is F, Cl, fluorinated alkyl or fluorinated alkoxy, fluorinated alkenyl or fluorinated CN or NCS,

When at least one of Z ^T1 and Z ^T2 is present, -C≡C-, and the remainder, if any, in the case where, independently of each other, and Z ^T1 is present twice also these independently 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,

n is 0, 1 or 2, preferably 0 or 1,

는, 서로 독립적으로, 및

가 2회 존재하는 경우 이들 또한 서로 독립적으로,

Independently of one another, and

Are present independently from each other,

임),

being),

A compound having one, two or more neutral permittivities selected from the group of compounds of the formulas (IV) and (V), preferably each of these one or more compounds:

(Wherein,

R ⁴¹ to R ⁵² independently of one another have the meanings given for R ² in the above formula II, preferably R ⁴¹ is alkyl and R ⁴² is alkyl or alkoxy, or R ⁴¹ is alkenyl and R ⁴² Is alkyl, preferably R ⁵¹ is alkyl and R ⁵² is alkyl or alkenyl, or R ⁵¹ is alkenyl and R ⁵² is alkyl or alkenyl, preferably alkyl,

는, 서로 독립적으로,

가 2회 존재하는 경우 이들 또한 서로 독립적으로,

Independently of one another,

Are present independently from each other,

이고,

ego,

중 적어도 하나가

이고,Preferably,

At least one of

ego,

는, 서로 독립적으로, 및

가 2회 존재하는 경우 이들 또한 서로 독립적으로,

Independently of one another, and

Are present independently from each other,

이고,

ego,

중 적어도 하나가

이고,Preferably,

At least one of

ego,

Z ⁴¹ to Z ⁵² independently of one another and, when Z ⁴¹ and / or Z ⁵¹ are present two times, also independently of one another are -CH ₂ CH ₂ -, -COO-, trans-CH = CH-, _{-CF = CF-, -CH 2 O-,} -CF 2 O-, and, -C≡C- or a single bond, preferably, Z ⁴¹ and Z ⁴² and Z ⁵¹ and Z ^52, at least one at least one of each of the Lt; / RTI >

p and q are, independently of each other, 0, 1 or 2 and p is preferably 0 or 1,

/ RTI >

Wherein the compound of formula (T) is excluded from the compound of formula (V).

Preferably, the medium is preferably a < RTI ID = 0.0 >

1 to 20%, preferably 2 to 18%, more preferably 3 to 16% of a compound of the formula G and / or

15 to 35%, preferably 20 to 30%, more preferably 23 to 26% of a compound of formula (I) and / or

0 to 35%, preferably 5 to 30%, more preferably 10 to 25% of a compound of formula (II-1) and / or

20-45%, preferably 25-40%, more preferably 30-35% of a compound of formula II-2, and / or

0 to 20%, preferably 5 to 15% of a compound of formula II-3, and / or

0 to 20%, preferably 5 to 15% of a compound of formula (III), and / or

0 to 20%, preferably 1 to 10% of a compound of formula (IV), and / or

0 to 20%, preferably 0 to 15% of a compound of formula (T), and / or

0 to 20%, preferably 0 to 15% of a compound of the formula V

.

Preferably, the medium comprises at least one compound of the formula G selected from the group of compounds of the formulas G-1 and G-2, preferably G-1:

In this formula,

The parameters have the respective meanings described above,

L ^G3 through L ^G7 are independently H and F independently of each other and other parameters, preferably L ^G1 and L ^G2 are both F, from 2 to 5, most preferably at least from L ^G3 through L ^G7 L ^G3 to L ^G5 are F and the rest of L ^G3 to L ^G7 is H or F, preferably F.

Particularly preferred compounds of formula G-1 used are the compounds of the following formulas G-1-1 to G-1-4, preferably G-1-4:

In this formula,

R ^G has the abovementioned meaning, preferably alkyl or alkenyl, more preferably alkyl.

In a preferred embodiment of the invention, the medium comprises at least one compound of formula (T) selected from the group of compounds of the formulas (T-1) and (T-2)

In the above formula, the parameters have the respective meanings given in the above formula (T)

L ^T1 to L ^T6 are independently of each other H or F, preferably 0, 1, 2 or 3 of them are F and the remainder are H.

In another preferred embodiment of the invention said medium is a compound of the formula T-2-1 selected from the group of compounds of the formulas T-2-1 and T-2-2, most preferably of the formula T-2-1 RTI ID = 0.0 > of: < / RTI &

In the above formula, the parameters have the respective meanings given in the above formula (T)

L ^T4 is preferably F.

In another preferred embodiment of the invention, the medium comprises, in addition to the compound of formula T-2, a compound of the formula T-1-1 and T-1-2, Lt; RTI ID = 0.0 > of T-1 < / RTI > selected from compounds of formula &

In the above formula, the parameters have the respective meanings given in the above formula (T)

R ^T1 is preferably alkyl,

R ^T2 is preferably alkoxy.

Alternatively, or in addition to the compounds of formulas II-1, II-2 and II-3 and / or III, the medium according to the invention may comprise at least one compound having a permittivity of the following formula VI:

In this formula,

R ⁶ is alkenyl having from 1 to 7 alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 2 to 7 carbon atoms, the alkene-yloxy, and the alkenyl alkoxy alkyl, or fluoride, preferably an alkyl or alkenyl ,

은, 서로 독립적으로,

Independently of one another,

이고,

ego,

L ⁶¹ and L ⁶² independently of one another are H or F, preferably L ⁶¹ is F,

X ⁶ 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 , F, Cl or -OCF ₃ ,

Z ⁶ represents -CH ₂ CH ₂ -, -CF ₂ CF ₂ -, -COO-, trans-CH═CH-, trans-CF═CF- or -CH ₂ O-, preferably -CH ₂ CH ₂ - , and -COO- or trans -CH = CH-, and most preferably -COO- or -CH ₂ CH _2,

r is 0 or 1;

In a preferred embodiment of the present invention, the liquid crystal medium according to the present invention comprises at least one polymerizable compound. The polymerizable compound is a non-mesogenic compound (e.g., well-known EHA or 2EHA) or a mesogenic compound. The polymerizable mesogenic compound is referred to herein as the " reactive mesogen "(abbreviated as RM). The polymerizable compound, whether mesogenic or non-mesogenic, can be mono-reactive or multi-reactive, preferably dissociated. Preferably, the medium comprises at least one one reactive compound and at least one multi-reactive, preferably the reactive compound. Most preferably, the medium comprises one or more RMs, but a non-mesogenic compound may additionally be present.

RM may be chiral or non-chiral, and may include an acrylate / methacrylate group or another polymerizable group. In a particularly preferred embodiment, RM is a chiral compound, because the compound, by polymerizing a certain amount of the chiral RM, thereby biting the liquid crystal material which is no longer available, Pitch and consequently selective reflection at longer wavelengths, so that the selective reflection wavelength can be simply adjusted. The resulting cholesteric pitch can be advantageously stabilized for further changes, for example, by using a suitable filter (e.g. UV filter) that protects the liquid crystal from ambient radiation.

When a chiral reactive mesogen is used in the liquid crystal medium according to the present invention, it is also preferable to use a photoinitiator in the medium when exposure to UV radiation is applied. The use of photoinitiators results in a significant reduction in the required UV radiation dose.

Chiral reactive mesogens can be used in the liquid crystal media according to the invention as the only chiral compound present in the medium. However, in a preferred embodiment of the present invention, chiral reactive mesogens are used with conventional (non-reactive) chiral dopants. In this preferred embodiment, a preferred starting value of the cholesteric pitch, or alternatively a value which is already somewhat close to the desired value, can be fixed by one or more conventional chiral dopant (s). Subsequently, the further use of one or more chiral reactive mesogens allows further adjustment of the cholesteric pitch by exposing the medium to UV radiation and subsequently depleting chiral reactive mesogens.

In the latter embodiment, in many cases, it is preferred to use conventional chiral dopant (s) and chiral reactive mesogen (s) with HTP with the same sign for each other. In this embodiment, only a small total concentration is required to achieve a short cholesteric pitch, and the overall physical properties of the mesogenic host material change only to a relatively small degree. This preferred embodiment results in a relatively low requirement to protect the medium against further changes in the selective reflection wavelength after the desired value is achieved by UV irradiation.

In some cases, however, it is advantageous to use one or more conventional chiral dopant (s) and one or more chiral reactive mesogen (s), wherein the conventional chiral dopant (s) And HTP of opposite sign. In this case, the center wavelength of the selective reflection can be fixed by the conventional chiral dopant (s). This central wavelength can then be shifted to a longer wavelength by the use of the chiral reactive mesogen (s). This effect can then be reversed by exposing the medium to UV radiation. In particular, this last preferred embodiment results in the lowest requirement to protect the medium against further changes in the selective reflection wavelength after the desired value is achieved by UV irradiation.

As a first approximation, the HTP of a mixture of chiral compounds (i. E., Conventional chiral dopants and chiral reactive mesogens) is approximated by adding each of these HTP values weighted by their respective concentrations in the medium It should be noted that

The RM can be one reactive, two reactive or multi-reactive. One or more of these reactive compounds (crosslinking agents), which are also preferably liquid crystals with functional groups at each end, or at least mesogenic, which may be based, for example, on a diacrylate based RM Is particularly preferable.

Where the medium comprises one or more polymerizable compounds, it preferably further comprises one or more polymerization initiators, such as photoinitiators and / or thermal initiators.

The liquid crystal medium according to the present invention may be stabilized by polymerization of each of the polymer precursors comprising one or more of the polymerizable compounds and optionally one or more of the initiators, or stabilized in a preferred embodiment. Preferably, the stabilizing polymer has the form of a polymer network. That is, a liquid crystal material having a low molecular weight (i.e., a non-polymerizable liquid crystal material / mesogenic material) exists in a somewhat continuous form arranged with a rather smooth strand of the polymeric material. Polymer network stabilized liquid crystals are disclosed, for example, in Dierking, I, Adv Mater 12, No 3, pp 167-181 (2000). In a preferred embodiment of the present invention, the liquid crystal medium according to the present invention comprises at least one polymerizable compound, preferably RM.

The host mixture contains a liquid crystal compound having a low molecular weight and at least one chiral dopant sufficient to cause selective reflection in the visible range of the electromagnetic spectrum. The cholesteric phase with a relatively short cholesteric pitch is preferably stabilized by the polymer. Stabilization of the (cholesteric) phase may be accomplished by adding to the chiral liquid crystal host mixture a mixture comprising at least one polymerizable compound, preferably RM, preferably one reactive, and the reactive RM and a suitable photoinitiator, For example, by exposure to UV radiation for a short period of time. Preferably, the polymerization is carried out in an all-optical cell maintained at a predetermined temperature on the cholesteric phase of the chiral liquid crystal host mixture.

The mesogenic monoreactive compounds according to the present invention preferably comprise one or more ring elements linked together by a direct bond or via a linking group wherein two of these ring members are optionally linked directly or via a linking group, (Which may be the same or different from the mentioned linking groups). The ring element is preferably selected from the group consisting of 4-membered, 5-membered, 6-membered or 7-membered, preferably 5-membered or 6-membered rings

The RMs to be used according to the invention are preferably selected from the group of compounds of the formulas VIIA and VIIB:

In this formula,

R ⁷¹ is preferably unsubstituted or monosubstituted with H, F, Cl, Br, I, CN, NO ₂ , NCS, SF ₅ , SO ₂ CF ₃ or unsubstituted or F, Cl, Br, Is straight or branched chain alkyl having 1 to 20 carbon atoms, wherein at least one non-adjacent CH ₂ group is optionally and independently at each occurrence, O and / or S atoms are not directly connected to each other, , -S-, -NH-, -NR ⁰¹ -, -SiR ⁰¹ R ⁰² -, -CO-, -COO-, -OCO-, -OCO-O-, -S- , -CY ⁰¹ = CY ⁰² or -C? C-), preferably H, halogen, n-alkyl or n-alkoxy having 1 to 7 carbon atoms, preferably 2 to 5 carbon atoms, Preferably alkenyl, alkenyloxy or alkoxyalkyl of 2 to 5 carbon atoms, or CN, NCS, halogen, preferably F, Cl, halogenated alkyl, alkenyl or alkoxy, preferably monofluorinated, Or oligo- fluorinated alkyl, alkenyl or alkoxy, A straight Advantageously CF _3, OCF ₂ H or OCF _3,

이고,R ⁰¹ and R ⁰² are, independently of each other, H, alkyl having 1 to 12 carbon atoms,

ego,

은, 바람직하게는 하나 이상의 고리를 포함하는 메소젠성 잔기, 가장 바람직하게는 구조식

의 2가 라디칼이고,

Is preferably a mesogenic residue comprising at least one ring, most preferably a moiety of the formula

Lt; / RTI > is a divalent radical of formula &

은, 서로 독립적으로, 방향족 및/또는 지환족 고리, 또는 둘 이상의 융합된 방향족 또는 지환족 고리를 포함하는 기이며, 이때 이들 고리는 임의적으로, N, O 및/또는 S로부터 선택되는 하나 이상의 헤테로 원자를 함유하고, 임의적으로 R⁷²에 의해 일치환 또는 다중치환되고,

Are independently from each other an aromatic and / or cycloaliphatic ring, or a group comprising two or more fused aromatic or cycloaliphatic rings, optionally containing one or more heteroatoms selected from N, O and / or S Atoms, optionally mono- or polysubstituted by R ⁷² ,

p and q are, independently of each other, 0, 1 or 2, preferably 0 or 1,

Preferably, (p + q) is 0, 1 or 2, preferably 1 or 2,

Z ⁷¹ to Z ⁷⁴ independently represent -O-, -S-, -CO-, -CO-O-, -O-CO-, -S-CO-, -CO- ^{CO-O-, -CO-NR 01} -, -NR 01 -CO-, -OCH 2 -, -CH 2 O-, -SCH 2 -, -CH 2 S-, -CF 2 O-, -OCF 2 -, -CF ₂ S-, -SCF- _, -CH ₂ CH ₂ -, -CF ₂ CH ₂ -, -CH ₂ CF ₂ -, -CF ₂ CF ₂ -, -CH = N-, -N = CH -, -N = N-, -CH = CR 01 -, -CY 01 = CY 02 -, -C≡C-, - (CH 2) 4 -, -CH = CH-CO-O-, -O- CO-CH = CH- or a single bond,

R ⁷² is H or alkyl, preferably H or alkyl of 1 to 10 carbon atoms,

PG ⁷¹ is a polymerizable group or a reactive group,

SP ⁷¹ is a spacer group or a single bond,

X ⁷¹ has one of the meanings given for Z ⁷¹ and is preferably -O-, -CO-O-, -O-CO-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ - or a single bond,

는 상기 화학식 VIIA 및 VIIB 하에

에 대해 제시된 의미를 갖고,

Lt; RTI ID = 0.0 > VIIA < / RTI &

≪ / RTI > has the meaning given for <

PG ⁷² and PG ⁷³ independently of one another have one of the meanings given for PG ⁷¹ ,

SP ⁷² and SP ⁷³ , independently of each other, have one of the meanings given for SP ¹¹ ,

X ⁷² and X ⁷³ independently of each other have one of the meanings given for X ⁷¹ above.

In a preferred embodiment of the present invention, the precursor of the polymer comprises, in addition to the compound (s) of the formula (VIIA), preferably at least one of the reactive mesogenic monomers of the formula (VIIB).

The compounds of formulas VIIA and VIIB according to the invention may be chiral compounds.

 Particularly preferred are polymer precursors comprising at least one compound of formula (VIIA) and / or (VIIB)

Z ⁷¹ and / or Z ⁷⁴ are independently selected from the group consisting of -O-, -CO-O-, -OCO-, -O-CO-O-, -CH ₂ -O-, -O-CH ₂ -, -CF ₂ -O -, -O-CF ₂ -, -C≡C-, -CH═CH- or a single bond, most preferably -CO-O- or -O-CO- or -O- and /

Z ⁷¹ is not a single bond and /

Ring A ⁷¹ is phenylene optionally substituted with one or more R groups and /

- R ⁷¹ is alkyl or alkoxy having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, or alkenyl, alkenyloxy or alkynyl having 2 to 12 carbon atoms, preferably 2 to 7 carbon atoms,

- SP ⁷¹ is alkylene of 1 to 12 carbon atoms, optionally monosubstituted or polysubstituted by F, wherein at least one non-adjacent CH ₂ is in each case independently of one another -O-, -CH = CH- Or -C≡C-, which may be replaced by a ring through a group selected from -O-, -CO-O-, -O-CO-, -O-CO-O- and a single bond, May be connected to the ring "A ⁷¹ " and /

- SP ⁷¹ is a single bond.

Preferred for MG ⁷² to X ⁷³ are the same as for MG ⁷¹ to X ⁷¹ .

In a preferred embodiment, rings A ⁷¹ to A ⁷³ are, independently of each other, an aromatic or alicyclic ring, preferably a 5-membered, 6-membered or 7-membered ring, or two or more, preferably two or three fused is a group containing an aromatic or alicyclic ring, where these rings are optionally containing one or more heteroatoms selected from N, O and / or S, and optionally mono- or multi by L ⁷ substituted, L ⁷ is F, Cl, Br, CN, OH, NO _2, and / or a carbon number from 1 to 12 alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl group, wherein one or more H atom is optionally substituted with F or Cl.

L ⁷ is preferably F, Cl, CN, OH, NO ₂ , CH ₃ , C ₂ H ₅ , OCH ₃ , OC ₂ H ₅ , COCH ₃ , COC ₂ H ₅ , COOCH ₃ , COOC ₂ H ₅ , CF ₃ , OCF ₃ , OCHF ₂ or OC ₂ F ₅ , especially F, Cl, CN, CH ₃ , C ₂ H ₅ , OCH ₃ , COCH ₃ or OCF ₃ , most preferably F, Cl, CH ₃ , OCH ₃ or a COCH _3.

Preferred rings A ⁷¹ to A ⁷³ are selected from the group consisting of furan, pyrrole, thiophene, oxazole, thiazole, thiadiazole, imidazole, phenylene, cyclohexylene, cyclohexeneylene, pyridine, pyrimidine, pyrazine, Azulene, indane, naphthalene, tetrahydronaphthalene, decahydronaphthalene, tetrahydropyran, anthracene, phenanthrene and fluorene.

Particularly preferably, at least one of these rings A ⁷¹ to A ⁷³ is furan-2,5-diyl, thiophene-2,5-diyl, thienothiophen-2,5-diyl, Diyl, pyrrol-2,5-diyl, 1,4-phenylene, azulene-2,6-diyl, pyridin-2,5-diyl, pyrimidine- Naphthalene-2,6-diyl, 1,2,3,4-tetrahydro-naphthalene-2,6-diyl, indan-2,5-diyl and 1,4-cyclohexylene ( Wherein one or two non-adjacent CH ₂ groups are optionally replaced by O and / or S, wherein these groups are unsubstituted or monosubstituted or polysubstituted by L as defined above.

은, 서로 독립적으로, Preferably,

Independently of one another,

(In the above formulas, R is alkyl having 1 to 12, preferably 1 to 7 C-atoms, or alkenyl or alkynyl having 2 to 12, preferably 2 to 7 C-atoms, , One or more non-adjacent -CH ₂ groups may be replaced by -O- and / or -CH = CH- and / or at least one H-atom may be replaced by a halogen, F)

Or an enantiomer thereof and / or, preferably,

은

이다.

silver

to be.

In a preferred embodiment of the present invention,

기는 단일환형 고리 A⁷¹ 내지 A⁷³만 함유한다. 매우 바람직하게는, 이는, 1 또는 2개의 5원 및/또는 6원 고리를 갖는 기이다.

Group contains only single cyclic rings A ⁷¹ to A ⁷³ . Very preferably, it is a group having one or two 5-membered and / or 6-membered rings.

Preferred sub-formulas of such groups are listed below. Phe is 1,4-phenylene, PheL is a 1,4-phenylene group substituted with one to four L groups as defined above, Cyc is 1,4-cyclohexylene, Hexyne, Pyd is pyridine-2,5-diyl, and Pyr is pyrimidine-2,5-diyl. The following list of preferred groups includes the following sub-formulas VII-1 to VII-20 and their enantiomers:

.

.

기는 하기 화학식 VIIa 내지 VIIj 및 이들의 거울상으로부터 선택된다:In these preferred groups, Z has the meaning of Z ⁷¹ as shown in formula VIIA. Preferably, Z is _{-COO-, -OCO-, -CH 2 CH 2} -, -C≡C- or a single bond. Very preferably,

Group is selected from the following formulas (VIIa) to (VIIj) and their enantiomers:

In this formula,

L is F, Cl, Br, CN, and OH, NO ₂ and / or C 1 alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl of 1 to 12 carbonyl groups, wherein one or more H atoms are optionally replaced by F or Cl ,

r is 0, 1, 2, 3 or 4, preferably 0, 1 or 2.

는 매우 바람직하게는

, 또한

이고, 이때 L은 각각 독립적으로 상기 제시된 의미 중 하나를 갖는다.In the above preferred formulas,

Is very preferably

, Also

, Wherein each L independently has one of the meanings given above.

기를 포함하며, 이때 r은 1 또는 2이다.Particularly preferred compounds of formulas VIIA and VIIB include at least one

Group, wherein r is 1 or 2.

기(이때, r은 1임) 및/또는 하나 이상의

기(이때, r은 2임)를 포함한다,Other preferred compounds of formula < RTI ID = 0.0 > VIIA < / RTI &

(Where r is 1) and / or one or more

Group, wherein r is 2,

는 더욱 바람직하게는

More preferably,

이고,

ego,

Wherein the 1,4-phenylene ring may optionally be substituted with R, preferably alkyl, preferably methyl, and / or alkoxy, and / or halogen, preferably F.

는More preferably,

The

Or their enantiomers, wherein R has the meanings given above, preferably alkyl having 1 to 6 carbon atoms, preferably n-alkyl, wherein one or more non-adjacent -CH ₂ - groups are optionally replaced by -O- and / / RTI > and / or -CH = CH- and / or at least one H atom may be replaced by a halogen, preferably F

In a preferred embodiment of the invention, the liquid crystal medium according to the invention comprises a compound of the following sub-formulas I-1 to I-5, preferably the compounds of the formulas I-2, I-4 and I- , More preferably compounds of the following sub-formulas I-2 and / or I-5, most preferably compounds of the following sub-formulas I-2 and I-5, Particularly preferably comprises the compounds of the sub-formulas I-2:

In this formula,

R < ¹ > has each of the meanings given for formula (I) above, preferably alkyl, most preferably n-

X ¹ is preferably CN.

In a preferred embodiment of the present invention, the liquid crystal medium according to the present invention comprises at least one compound of the formulas II-1 and II-2.

Preferably the medium comprises at least one compound of formula II-1, preferably II-1a, selected from the group of compounds of formula II-1a and II-1b:

Wherein L ²¹ and L ²² are both F and L ³² and L ²⁴ are both H or preferably L ²¹ , L ²² , L ²³ And L ²⁴ are both F.

In a preferred embodiment, the medium comprises at least one compound of formula (II-1c) wherein L ²¹ , L ²² , L ²³ and L ²⁴ are both F.

Preferably, the medium comprises, in addition to or in addition to the compound (s) of formula (II-1), a compound of formula II-2a to II-2d, preferably a compound of formula II-2b to II-2d , More preferably one or more compounds selected from the group consisting of II-2b, II-2c and II-2d,

In this formula,

In the above equation, the parameters have the respective meanings given above,

L ²³ to L ²⁵⁷ are H or F independently of each other and other parameters, preferably L ²¹ and L ²² are both F, two or three of L ²³ to L ²⁵ , , L ²³ to L ²⁵ are F, and the rest of L ²¹ to L ²⁵ is H or F, preferably H,

X ² is preferably F or -OCF ₃ , most preferably F.

Preferably, the medium further comprises, in addition to the compound (s) of the formulas II-1 and / or II-2, preferably one or more compounds selected from the group of compounds of the formulas II-3a and II- Compounds of formula (II-3), preferably compounds of formula (II-3a) and (II-3b)

In the above equation, the parameters have the respective meanings given above,

L ²³ to L ²⁷ , independently of each other and with other parameters, are H or F, preferably L ²¹ and L ²² are both F, two or three of L ²³ to L ²⁷ , , L ²³ to L ²⁵ are F, and the rest of L ²¹ to L ²⁷ is H or F, preferably H,

X ² is preferably F or -OCF ₃ , most preferably F.

A particularly preferred compound of formula II-3 used is a compound of formula II-3b-1:

Wherein R < ² > has the significance given above.

In another preferred embodiment of the present invention, the medium comprises at least one compound selected from the group of compounds of the formulas III-1 and III-2:

In the above formula, the parameters have the respective meanings given for the above formula (III).

Preferably, the medium comprises at least one compound selected from the group consisting of compounds of the following formulas III-1a to III-1f, preferably compounds of the following formulas III-1a, III-1c and III- 1-c and / or III-1f, preferably at least one compound of the following formulas III-1a and / or III-1c and / or III- Includes:

In the above equation, the parameters have the respective meanings given above,

L ³³ to L ³⁷ , independently of each other and other parameters, are H or F, L ³¹ and L ³² are preferably both F, two or three of L ³³ to L ³⁷ , L ³³ to L ³⁵ are F, and the rest of L ³¹ to L ³⁷ is H or F, preferably H,

X ³ is preferably F or -OCF ₃ .

Most preferred compounds of formula III-1 are selected from the group of compounds of formula III-1a-1, III-1c-1 and III-1d-1,

Wherein R < ³ > has the significance given above.

Preferably, the compound of formula IV is selected from the group of compounds of formulas IV-1 to IV-7, more preferably the compounds of formula IV-6 and / or IV-7:

Wherein, R ⁴¹ and R ⁴² having the respective meanings given in the formula IV, generally, and in particular, in the formula IV-1 and IV-5, R ⁴¹ is preferably alkyl or alkenyl, preferably Al And R ⁴² is preferably alkyl or alkenyl, preferably alkyl; alternatively, in formula IV-2, R ⁴¹ and R ⁴² are preferably both alkyl; in formula IV-4, R ⁴¹ Is preferably alkyl or alkenyl, preferably alkyl, and R < ⁴² > is preferably alkyl or alkoxy, preferably alkoxy.

Preferably the medium comprises at least one compound selected from the group of compounds of formulas IV-6 and IV-7, most preferably at least one compound of each of formulas IV-6 and IV-7.

A preferred compound of formula IV-6 is a compound of formula CPTP-n-m and CPTP-n-Om, more preferably a compound of CPTP-n-Om. Preferred compounds of formula IV-7 are compounds of formula CPGP-n-m. The definitions of these abbreviations (acronyms) are illustrated in the following Tables A to C and are illustrated in Table D below.

In a preferred embodiment, the liquid crystal medium according to the invention comprises at least one compound of the formula V selected from the group of compounds of the formulas V-1 to V-4:

Wherein R ⁵¹ and R ⁵² have the respective meanings given in the above formula V, R ⁵¹ is preferably alkyl, more preferably n-alkyl, and in the formula V-1, R ⁵² is preferably an alkyl And most preferably - (CH ₂ ) ₂ -CH = CH-CH ₃ , and in the formula V-3, R ⁵² is preferably alkyl or alkenyl, preferably Is hydrogen or lower alkyl, and most preferably is - (CH ₂ ) ₂ -CH = CH ₂ , R ⁵² in formula V-3 is preferably alkyl, and in formula V- _0/1 "is preferably F.

Preferred compounds of the formula V-1 are the compounds of the formulas PP-n-2V and PP-n-2Vm, more preferably the compounds of the formula PP-1-2V1. Preferred compounds of formula V-2 are those of formula PGP-nm, PGP-n-2V and PGP-n-2Vm, more preferably compounds of formula PGP-2-m, PGP-3-m and PGP- / RTI > A preferred compound of formula V-3 is a compound of formula PGGIP-n-m. A preferred compound of formula V-4 is a compound of formula PGIGP-n-m. The definitions of these abbreviations (acronyms) are illustrated in the following Tables A to C and are illustrated in Table D below.

A preferred compound of formula T-1 is a compound of formula PTP-n-Om, wherein the compounds of formula PTP-1-O2, PTP-2-O1 and PTP-3-O1 are particularly preferred. Preferred compounds of the formula T-2 are compounds of the formula PPTUI-n-m, with the compounds of the formulas PPTUI-3-2, PPTUI-3-3, PPTUI-3-4 and PPTUI-4-4 being particularly preferred.

The compound of formula (VI) is preferably selected from the group of compounds of formula (VI-1) and (VI-2), preferably a compound of formula (VI-1)

In the above equation, the parameters have the respective meanings given above,

The parameters L ⁶³ and L ⁶⁴ , independently of each other and other parameters, are H or F, preferably Z ⁶ is -CH ₂ -CH ₂ -, preferably X ⁶ is F.

Preferably, the liquid crystal medium according to the present invention is a liquid crystal medium according to the present invention which comprises a compound of the formula I, II-1 to II-3 and III to VI and VIIa and VIIb and T, more preferably a compound of the formula I, II- II-3 and III to V and VIIa and / or VIIb and T, more preferably consists essentially of, or more preferably consists essentially of, Most preferably they consist entirely of these compounds.

"Contained in the context of a composition" is used herein to mean that an entity (eg, a medium or component) referred to herein is capable of dissolving the component (s) or compound (s) , And most preferably 20% or more.

As used herein, "predominantly ", unless stated otherwise, means that the entity referred to contains at least 55%, preferably at least 60%, and most preferably at least 70% of the component (s) or compound .

As used herein, "consisting essentially of " means that the entity referred to does not exceed 80%, preferably 90% or more, and most preferably 95% or more, of the component (s) or compound .

Means that the named entity contains at least 98%, preferably at least 99%, and most preferably 100.0% of the component (s) or compound (s), unless explicitly stated otherwise .

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

The liquid crystal medium according to the present invention has a brightening point of 85 DEG C or higher, preferably 90 DEG C or higher.

The Δn of the liquid crystal medium according to the present invention at 589 nm (Na ^D ) and 20 ° C. is preferably in the range of 0.150 to 0.350, more preferably in the range of 0.170 to 0.250, and most preferably in the range of 0.180 to 0.220 .

The DELTA epsilon of the liquid crystal medium according to the invention at 1 kHz and 20 DEG C is preferably not less than 10, preferably not less than 15, more preferably not less than 20, most preferably not less than 25, preferably not more than 40, More preferably 35 or less, still more preferably 10 or more and 40 or less, and most preferably 20 to 30 or less.

The nematic phase of the medium according to the invention without chiral dopant is preferably at least 0 ° C to 80 ° C or higher, more preferably at least -20 ° C to 85 ° C or higher, and most preferably at least -20 ° C or lower Lt; RTI ID = 0.0 > 90 C, < / RTI >

The liquid crystal medium is preferably a TN display operating at a second transmittance minimum according to Gooch and Tarry with an optical phase difference d 占 within a range of 1.0 占 퐉 to 1.1 占 퐉, . However, it is preferably used as a cholesteric liquid crystal (also referred to as chiral nematic liquid crystal) having a somewhat short cholesteric pitch, and its cholesteric pitch preferably has a selective reflection wavelength of the electromagnetic spectrum Is selected to be within the visible light range (i.e., 400 to 800 nm).

The liquid crystal medium preferably has a spiral twist in a range of 20 占 퐉 ^-1 or more, preferably 40 占 퐉 ^-1 or more, more preferably 60 占 퐉 ^-1 or more, and most preferably 80 占 퐉 ^-1 or more and 260 占 퐉 ^-1 or less And at least one chiral dopant having an absolute value of helical twisting power (HTP).

Preferably, the liquid crystal medium is a compound of formula I, II-1, II-2, II-3, III, IV, V, VI and T, Preferably 50 to 100%, more preferably 70 to 100%, still more preferably 80 to 100%, particularly 90 to 100%, of the compounds of Formulas II-3, III and IV.

More preferably, the liquid crystal medium is a compound of formula I, II-1, II-2, II-3, III, IV, V, VI and T, , II-3, III and IV, more preferably consists essentially of, or more preferably consists essentially of, or most preferably consists solely of, of these.

The individual single compounds of formula I are preferably present in an amount of from 1% to 15%, more preferably from 2% to 13%, more preferably from 3% to 11%, and most preferably from 5% to 10% And is used for the medium in a total concentration. In the composition of the liquid crystal medium, the concentration limit applies only to the host mixture.

The concentration (s) of various additives, especially chiral dopants, polymerizable compounds and other additives such as stabilizers and dichroic dyes, are not counted unless expressly stated otherwise.

Preferably the polymerizable compounds of formula VIIA and / or VIIB are preferably present in the medium at a total concentration of 0 to 20%, more preferably 2 to 17%, and most preferably 5 to 14% Is used.

Preferably, at least one polymerization initiator, preferably at least one photoinitiator, is used. The concentration of the initiator is 0.1-10%, more preferably 0.2-5%, most preferably 0.5-2% of the total concentration of the polymerizable compounds.

Preferably, the medium according to the present invention further comprises one or more chiral compounds as chiral dopants to adjust its cholesteric pitch. The total concentration thereof in the medium according to the invention is preferably in the range of from 0.1 to 15%, more preferably from 1 to 10%, most preferably from 2 to 6%, relative to the host mixture, Do not.

Optionally, the medium according to the present invention may comprise additional liquid crystal compounds to adjust the physical properties. Such compounds are known to those skilled in the art. The concentration thereof in the medium according to the present invention is preferably 0 to 30%, more preferably 0.1 to 20%, and most preferably 1 to 15%.

The liquid crystal medium according to the present invention has a clearing point of 85 DEG C or higher, preferably 90 DEG C or higher, more preferably 100 DEG C or higher, most preferably 120 DEG C or higher, or even 130 DEG C or higher.

The liquid crystal medium according to the present invention preferably has a birefringence index of 0.150 or more and 0.400 or less, preferably 0.200 or more and 0.350 or less, and most preferably 0.240 or more and 0.330 or less.

Preferably, the liquid crystal medium according to the present invention has a dielectric anisotropy of 10 or more and 70 or less, preferably 20 or more and 60 or less, and most preferably 30 or more and 55 or less.

Preferably, the medium according to the invention comprises at least one compound of the formula:

- a compound of formula I-2, preferably at a concentration of from 20 to 40%, and / or

- a compound of formula I-5, preferably at a concentration of 5 to 20%, and / or

- a compound of the formula II-1c, preferably a compound of the formula PUQU-n-F, and / or

- a compound of formula II-2c, preferably a compound of formula II-2c-1, and / or

- a compound of formula III-1c, preferably a compound of formula III-1c-1, and / or

- a compound of the formula III-1d and / or III-1f, preferably a compound of the formula III-1f, and / or

A compound of formula IV-6, preferably a compound of formula CPTP-n-Om and / or CPTP-n-m, and / or

A compound of formula IV-7, preferably of the formula CPGP-n-Om and / or CPGP-n-m, and / or

- a compound of the formula V-1, preferably the formula PP-n-mV, and / or PP-n-mVl, and /

A compound of formula V-2, preferably a compound of formula PGP-n-m and / or PGP-n-mV, and / or

- a compound of the formula R-5011 or S-5011, and / or

At least one reactive polymerizable compound, and / or

At least one polymerization initiator.

As used herein, the term " dielectrically positive "is used for a compound or component having an [epsilon] of greater than 3.0, and the expression" dielectrically neutral " Is used for a compound or component having??, And the expression "dielectrically negative" is used for a compound or component having? ? Is determined at a frequency of 1 kHz and at 20 占 폚. The dielectric anisotropy of each compound is determined from the results of a 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 doubled until the resulting mixture is stable enough to at least determine its properties. Preferably, however, the concentration is maintained at least 5% to keep the significance of the result as high as possible. The capacity of the test mixture is determined in both cells with homeotropic alignment and cells with homogeneous alignment. In both types of cells, the cell spacing is about 20 [mu] m. The applied voltage is a rectangular wave with a frequency of 1 kHz, typically a mean square root of 0.5 to 1.0 V (rms), but this is always selected to be less than the threshold value of the capacity of each test mixture.

Δε is defined as _{(ε ∥ -ε ⊥), ε} av is defined as _{/ 3 (ε ∥ + 2ε ⊥} ). For compounds having a positive dielectric constant, the mixture ZLI-4792 is used, and for compounds having a negative dielectric constant as well as for compounds having a neutral dielectric constant, the mixture ZLI-3086 is used as the host mixture, It is a product of Merck KGaA. The permittivity of the compound is determined from the change in the respective value of the host mixture when the compound of interest is added. The value is extrapolated to a 100% concentration of the compound of interest.

The components having a nematic phase at a measurement temperature of 20 DEG C are measured as such and the others are handled like compounds.

Unless expressly stated otherwise, the term " threshold voltage "herein refers to an optical threshold and is presented for a 10% relative contrast (V ₁₀ ), the term" saturation voltage " % Relative contrast (V ₉₀ ). Likewise, the capacitive threshold voltage (V ₀ ), also referred to as the Freedericks-threshold (V _Fr ), is used only when explicitly mentioned.

Unless expressly stated otherwise, all ranges of parameters set forth herein include limits.

Unless expressly stated otherwise, all concentrations throughout the disclosure are presented in mass%, and for each entire mixture, all temperatures are given in degrees Celsius, and all temperature differences are presented in degrees Celsius. All physical properties are described in "Merck Liquid Crystals, Physical Properties of Liquid Crystals ", Status Nov. 1997, Merck KGaA, Germany] and is presented for a temperature of 20 ° C, unless expressly stated otherwise. The optical anisotropy (? N) is determined at a wavelength of 589.3 nm. The dielectric anisotropy (DELTA epsilon) is determined at the frequency of 1 kHz. All other electrical properties as well as the threshold voltage were measured using a test cell manufactured by Merck KGaA in Germany. The test cell for measuring [Delta] [theta] had a cell spacing of about 20 [mu] m. The electrode was a circular ITO electrode with an area of 1.13 cm 2 and a guard ring. The orientation layer was homeotropic alignment was for (ε _⊥) lecithin, a flat horizontally oriented polyimide AL-1054 of Japanese Shin tetik rubber (Synthetic Rubber) for (ε _∥). The capacitance was determined with a frequency response analyzer Solatron 1260 using a sine wave with a voltage of 0.3 V _rms . The test cell used had cell spacing (typically about 0.45 mu m <" ¹ >) selected to have an optical retardation that matched below the first transmittance minimum according to the molar and terry. The light used for the all-optical measurement was white light. We used equipment available from Autronic-Melchers, Karlsruhe, Germany. The characteristic voltage was determined under vertical observation. The threshold voltage V ₁₀ , the mid-gray voltage V ₅₀ and the saturation voltage V ₉₀ were determined for 10%, 50% and 90% relative contrast, respectively.

Response time is again a 10% increase from the time (τ _on), 100% for zero to a change time of the 90% relative contrast (t ₉₀ -t ₀₎ (i.e., the delay time (with t ₁₀ -t _0)), respectively It is presented as decay time (τ _off), and the total response time (τ = τ _{on total} + τ _off) time for the change of the relative contrast back to the (t ₁₀₀ -t _10).

The liquid crystal medium according to the present invention may contain further additives in usual concentrations. The total concentration of these additional components ranges 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 0.1 to 3%. Concentration values and ranges of liquid crystal components and compounds of the liquid crystal medium in this application do not take into account the concentrations of the additional additives and similar additives. It is also maintained at the concentration of the dichroic dye used in the mixture (not counted unless the concentration of the compound or components of the host mixture is specified). The concentration of each of the above additives is always presented for the final doped mixture.

The liquid crystal medium according to the present invention comprises several compounds, preferably 3 to 30, more preferably 4 to 20, most preferably 4 to 16 compounds. These compounds are mixed in a conventional manner. In general, compounds used in smaller amounts are more soluble in compounds used. It is particularly easy to observe the completion of the dissolution process at a temperature higher than the clearing point of the compound used at a higher concentration. However, it is also possible to use a so-called pre-mixture, which may be a homogeneous or eutectic mixture of the compound, or a so-called multi-container system (multi -bottle-systems) may be used to prepare the media.

Preferably, the liquid crystal medium according to the present invention comprising one or more chiral dopants selectively reflects radiation in the visible range (i.e., in the range of 400 to 800 nm) of the electromagnetic spectrum. Preferably, the band of selective reflection thereof extends into said wavelength range, more preferably the center wavelength of its reflection band lies within said range, most preferably its full reflection band lies within said range. Preferably, it has a selective reflection of a half band width (1/2 FWHM) in the range of 15 to 60 nm, preferably 20 to 55 nm, most preferably 25 to 50 nm. In particular, the relative half band width (i.e., the ratio of the half band width and the center wavelength of the reflection band) is preferably in the range of 1% to 20%, more preferably in the range of 2% to 16% 10%, and most preferably in the range of 6% to 8%.

The center wavelength of the resulting selective reflection at a given temperature can be calculated from the actual concentration of the chiral dopant in the host used, through the approximation of the following polynomial series (I).

In this formula,

?,? and? are specific material constants for the combination of the presented chiral dopants in the host mixture shown.

c (dop.) is the concentration of the chiral dopant in the host mixture.

In many practical cases, the linear term ("α · [c (dop.)] ^-1 ") provides sufficiently accurate results, even if only the first term is taken into account. The parameter "a" is similar to the reciprocal of HTP (i.e., HTP- ¹ ). Here, in determining the wavelength of the selective reflection of the cholesteric LC (which is analogous to the "Bragg" reflection), the effective refractive index of the mixture should be additionally considered for more accurate numerical calculations.

Typically, the parameters alpha, beta and gamma are more strongly dependent on the type of chiral dopant than the particular liquid crystal mixture used.

Obviously, they depend on the enantiomeric excess of each chiral dopant. They have their respective maximum absolute values for pure enantiomers and 0 for racemates. In the present application, the values given are values for pure enantiomers with an enantiomeric excess of 98% or more.

Preferably, the absolute value of the parameter a of each chiral dopant (s) in each liquid crystal medium according to the invention is in the range of 5 to 25 nm, more preferably 10 to 20 nm, most preferably 12 to 16 nm nm.

The medium may comprise more than one chiral dopant. In the case where the medium comprises two or more chiral dopants, it is advantageous if the medium has a glass transition temperature in one of the known modes of compensating for, for example, the temperature dependence of the cholesteric pitch and thus the temperature dependence of the selective reflection wavelength . ≪ / RTI > Here, depending on the parameter of the higher order term of the polynomial (I) in the host mixture, in particular the characteristic of the parameter beta, which is the parameter of the quadratic term, the chiral dopant having the same sign parameter a as well as the opposite sign Chiral dopants with parameters can be used.

More preferably an embodiment of the invention using a single chiral dopant, which shows a low temperature dependence of the chiral pitch induced in each host mixture (i. E., Has a small parameter beta). By adding suitable additives, the liquid crystal medium according to the present invention can be applied to all known types of liquid crystal displays using liquid crystal media such as TN, TN-AMD, ECB-AMD, VAN-AMD, IPS and OCB LCD, , NCAP, PN LCD, and especially ASM-PA LCD.

The transition T (S, N) from the melting point T (C, N), the smectic phase S to the nematic phase N and the nominal point T (N, I) of the liquid crystal are presented in degrees Celsius.

In the present specification, particularly in the following examples, the structure of the liquid crystal compound is represented by an acronym (also referred to as an "acronym"). Converting an abbreviation to its corresponding formula is simple according to the following three Tables A to C.

All C _n H _{2n + 1} , C _m H _{2m + 1} and C ₁ H _{2l + 1} groups are straight chain alkyl groups having n, m and 1 carbon atoms respectively and all C _n H _2n , C _m H _2m and The C ₁ H _2l groups are preferably (CH ₂ ) _n , (CH ₂ ) _m and (CH ₂ ) _l , respectively, and -CH═CH- is preferably trans- or E -vinylene.

Table A lists the symbols used for the ring elements, Table B lists the symbols for the linker, and Table C lists the symbols for the left and right terminal groups of the molecule.

Table D below lists the exemplary structures of the molecules and their respective codes together.

Table A: Ring elements

Table B: Connectors

Table C:

In the above, n and m are integers, respectively, and "... " represents the spacing distance from other abbreviations in the table.

Preferably, the liquid crystal medium according to the invention comprises, in addition to the compound (s) of the formula (I), at least one compound selected from the group of compounds of the formula (D) below.

Table D

Table E below lists the chiral dopants which are preferably used in the liquid crystal media according to the invention.

Table E

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

Table F lists the stabilizers preferably used in the liquid crystal media according to the present invention.

Table F

Note: In the above table, "n" means an integer ranging from 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 of compounds of Table F.

The liquid crystal medium according to the invention preferably comprises at least 4, preferably at least 6 compounds selected from the group of compounds of Table D, preferably at least 7, Preferably at least 8, preferably at least 3 different compounds.

Example

The embodiments presented below illustrate the invention without limiting the invention in any way.

However, the physical properties and composition show those skilled in the art how certain characteristics can be obtained and how the range can be modified. In particular, a combination of various characteristics that can preferably be achieved is well defined for those skilled in the art.

A liquid crystal mixture was implemented with the compositions and characteristics shown in the following table. Its optical performance was investigated. In particular, its reflection spectra were recorded.

Comparative Examples 1.0 to 1.2

Comparative Example CE-1.0

Table 1: Composition and characteristics of liquid crystal mixture CE-1.0

Comparative Example CE-1.1

2.65% chiral dopant R-5011, 0.5% Irgacure 907, 5% of the following bisacrylate RM RM1

And 0.5% of the following second bisacrylate RM RM2

Was added to a 86.85% mixture CE-0 from the above comparative example to prepare each cholesteric mixture (referred to as CE-1) having a relatively short cholesteric pitch. The conspicuous point of the mixture CE-1.1 was 119.5 ° C.

The mixture was stirred at 60 < 0 > C for 30 minutes. The mixture was then charged to a test cell having a cell gap of 6 mu m through capillary filling on a temperature controlled hot plate at 60 < 0 > C. The test cell had a rubbed polyimide alignment layer for a TN configuration on a 1 cm square patterned ITO. The test cell was then annealed at 130 캜 for 10 seconds to remove the flow alignment. The reactive mesogen was then polymerized by UV irradiation at a wavelength of 365 nm at 10 mW / cm ² for 10 min.

The mixture CE-1.1 showed a reflection in the green range of the spectrum in the range of 530 nm to 600 nm (FWHM) around 565 nm.

Comparative Example CE-1.2

The addition of 2.65% chiral dopant R-5011, 0.5% Irgacure 907, 5% RM1 and 8% RM2 to 83.70% mixture CE-1.0 from the above comparative example, Each cholesteric mixture (referred to as CE-1.2) having a rak pitch was prepared. The conspicuous point of the mixture CE-1.2 was 119.0 ° C.

Test cells were prepared for mixture CE-1.2 as described above. The mixture CE-1.2 showed a reflection in the range of 370 nm to 745 nm (FWHM) around 531 nm in a broad spectrum.

Examples 1.1 to 1.3

Compounds of Comparative Example 1.0 The compounds of the formula GUUQU-n-N were added in increasing amounts according to the concentrations given in the following table and the physical properties of the resulting mixture were investigated in CE-1.0.

Table 2: Composition and properties of liquid crystal mixtures CE-1.0 and 1.1 to 1.3

Examples 1.2.1 and 1.2.2

Table 3: Composition and characteristics of liquid crystal mixture A-1.2

As in Comparative Example 1.1, 2.65% chiral dopant R-5011, 0.5% Irgacure 907, 5% RM1 and 5% RM2 were added to 86.85% mixture A-1.2 from Example 1.2 Were added to prepare each cholesteric mixture (referred to as A-1.2.1) having a relatively short cholesteric pitch. The clarification point of the mixture A-1.2.1 was 118.0 占 폚.

Test cells were prepared and examined as described above. The mixture A-1.2.1 showed a reflection in the range of 550 nm to 620 nm (FWHM) around 580 nm in a broad spectrum.

As in Comparative Example 1.2, 2.65% chiral dopant R-5011, 0.65% Irgacure 907, 5% RM1 and 8% RM2 were added to 83.70% mixture A-1.2 from Example 1.2 To prepare each cholesteric mixture (referred to as A-1.2.2) having a relatively short cholesteric pitch. The clarification point of the mixture A-1.2.2 was 116.5 ° C.

Test cells were prepared and examined as described above. The mixture A-1.2.2 showed a reflection in the range of 370 nm to 740 nm (FWHM) around 555 nm in a broad spectrum.

These data are shown in Table 4 below. The cell with the material according to the invention showed almost the same reflectivity as the cell with each comparative material. They also exhibited a very broad reflection spectrum at the polymerization of the polymer precursor like the comparative material.

The operating voltage of the cell with the material having the polymerized precursor was also investigated. The cell gap between two glasses with 1 cm square patterned ITO was 6.4 mu m.

The materials according to the invention, i.e. the cells with Examples 1.2.1 and 1.2.2, respectively, showed significantly lower working voltages than the comparative materials of the corresponding Comparative Examples 1.1 and 1.2, respectively. The operating voltage was significantly reduced by 100 V or even more.

Table 4: Results of Comparative Examples 1.1 and 1.2 and Examples 1.2.1 and 1.2.2

week:

Color: The color of the selectively reflected light,

λ _min. And? _Max. : Presented at half maximum respectively,

Δλ / 2 ≡ (λ _min - λ _max. ) / 2 (ie the total width at half maximum),

λ _cent. ≡ (λ _min. + Λ _max. ) / 2, and

α ≡ c (R-5011) · λ _cent. Or c (S-5011) -? _Cent .

V _op ≡ D65 The voltage required to increase the transmittance in excess of 70% of the light source with light.

Claims (13)

- one or more compounds of formula (I)

(Wherein,
R ¹ is alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy, alkenyl, alkenyloxy, alkoxyalkyl, fluorinated alkenyl or fluorinated alkenyloxy,

The

ego,
L ¹¹ and L ¹² are independently of each other H or F,
X < ¹ > is CN or NCS,
i is 0 or 1,
Two, or more compounds of the formula G < RTI ID = 0.0 >:< / RTI &

(Wherein,
R ^G is alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 carbon atoms, alkenyl having 2 to 7 carbon atoms, alkenyloxy, alkoxyalkyl or alkenyl, and R ² and R ³ are preferably Lt; / RTI > is alkyl or alkenyl,

Lt; / RTI >

ego,
L ^G1 and L ^G2 are independently of each other H or F,
X ^G is CN or NCS, preferably CN, and
Optionally, one or more chiral compounds
≪ / RTI > The method according to claim 1,
Characterized in that the total concentration of the compound of formula (I) in the medium is in the range of 11% to 39%. 3. The method according to claim 1 or 2,
Characterized in that the liquid crystal medium further comprises at least one compound selected from the group of compounds of the formulas II-1, II-2, II-3 and III:

(Wherein,
R ² is alkyl having 1 to 7 carbon atoms, alkoxy, fluorinated alkyl or fluorinated alkoxy, alkenyl having 2 to 7 carbon atoms, alkenyloxy, alkoxyalkyl or alkenyl, preferably R ² and R ³ Lt; / RTI > is alkyl or alkenyl,

At least one of

ego,

Lt; / RTI > independently of one another,

ego,
L ²¹ and L ²² independently of one another are H or F, preferably L ²¹ and / or L ²² are F, preferably L ²¹ and L ²² are both F,
X ² 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 , F, Cl or -OCF ₃ )

(Wherein,
R ² and R ³ independently of one another are alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 carbon atoms, alkenyl having 2 to 7 carbon atoms, alkenyloxy, alkoxyalkyl or fluorinated alkenyl,

Independently of one another,

ego,

Independently of one another,

ego,
L ²¹ , L ²² , L ³¹ and L ³² are each independently H or F,
X ² and X ³ are independently of each other 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 independently of each other 0 or 1). 4. The method according to any one of claims 1 to 3,
Wherein the liquid crystal medium further comprises at least one compound selected from the group of the following formulas IV and V:

In this formula,
R ⁴¹ to R ⁵² independently of one another have the meanings given for R ² in the first paragraph,

Independently of one another, and

Are present independently from each other,

ego,

Independently of one another, and

Are present independently from each other,

ego,
Z ⁴¹ to Z ⁵² independently of one another and, when Z ⁴¹ and / or Z ⁵¹ are present two times, also independently of one another are -CH ₂ CH ₂ -, -COO-, trans-CH = CH-, -CF = CF-, -CH ₂ O-, -CF ₂ O-, -C≡C- or a single bond,
p and q are, independently of each other, 0, 1 or 2; 5. The method according to any one of claims 1 to 4,
Characterized in that the liquid crystal medium comprises one or more compounds of the general formula (I-2) in a concentration of preferably 15 to 35%

Wherein R ¹ and X ¹ have the respective meanings given in claim 1. 6. The method according to any one of claims 3 to 5,
Characterized in that the liquid crystal medium comprises at least one compound of formula (III) as set forth in claim 3. 6. The method according to any one of claims 1 to 5,
Characterized in that the liquid crystal medium comprises a compound of the formula R-5011 or an enantiomer thereof, S-5011:

. 8. The method according to any one of claims 1 to 7,
Lt; RTI ID = 0.0 > 1, < / RTI > wherein the liquid crystal medium further comprises at least one polymerizable compound. At least one compound of formula I, at least one compound of formula II-1 and / or II-2, and optionally at least one compound of formula II-3 and / or III and / or one or more compounds of formula IV and / And / or one or more chiral compounds and / or one or more polymerizable compounds. ≪ RTI ID = 0.0 > 8. < / RTI > A composite material comprising a low molecular weight liquid crystalline medium and a polymer obtainable or obtainable from the liquid crystalline medium according to claim 8. A method for producing a composite material according to claim 10 by polymerizing a polymer precursor in a liquid crystal medium. A liquid crystal display comprising a liquid crystal medium according to any one of claims 1 to 8 or a composite material according to claim 10. Use of a liquid crystal medium according to any one of claims 1 to 8 or a composite material according to claim 10 in a liquid crystal display.