TWI827573B - Liquid-crystalline medium - Google Patents

Abstract

The invention relates to a liquid-crystalline medium which comprises at least one compound of the formula I, and one or more compounds selected from the group of the compounds of the formulae IIA, IIB and IIC,

Description

liquid crystal medium

The present invention relates to a liquid crystal medium containing one or more compounds of formula I,

、

、-O-、-CO-O-或-O-CO-置換，且其中另外，一或多個H原子可經鹵素置換，A¹ 在每次出現時彼此獨立地指代a)1,4-伸環己烯基或1,4-伸環己基，其中一或兩個不相鄰CH₂基團可經-O-或-S-置換，b)1,4-伸苯基，其中一或兩個CH基團可經N置換，c)來自基團哌啶-1,4-二基、1,4-雙環[2.2.2]伸辛基、萘-2,6-二基、十氫萘-2,6-二基、1,2,3,4-四氫萘-2,6-二基、菲-2,7-二基及茀-2,7-二基之群的基團， 其中基團a)、b)及c)可經鹵素原子單取代或多取代，a 指代1或2，較佳地1，Z¹ 在每次出現時彼此獨立地指代-CO-O-、-O-CO-、-CF₂O-、-OCF₂-、-CH₂O-、-OCH₂-、-CH₂-、-CH₂CH₂-、-(CH₂)₄-、-CH=CH-CH₂O-、-C₂F₄-、-CH₂CF₂-、-CF₂CH₂-、-CF=CF-、-CH=CF-、-CF=CH-、-CH=CH-、-C≡C-或單鍵，且L¹¹及L¹²各自彼此獨立地指代F、Cl、CF₃或CHF₂，較佳地H或F，最佳地F，以及選自式IIA、IIB及IIC之化合物之群的一或多種化合物

wherein R ¹¹ and R ¹² each independently refer to H, an alkyl group having 1 to 15 C atoms, or an alkoxy group, wherein in addition, one or more CH ₂ groups in these groups may make O atoms Not directly bonded to each other via -C≡C-, -CF ₂ O-, -OCF ₂ -, -CH=CH-,

,

, -O-, -CO-O- or -O-CO-, and where in addition one or more H atoms may be replaced by halogen, A ¹ refers independently to each other on each occurrence of a) 1,4 - cyclohexenyl or 1,4-cyclohexylene, one or two non-adjacent CH ₂ groups may be replaced by -O- or -S-, b) 1,4-phenylene, one of which Or two CH groups may be replaced by N, c) from the groups piperidin-1,4-diyl, 1,4-bicyclo[2.2.2]octyl, naphthalene-2,6-diyl, deca Hydronaphthalene-2,6-diyl, 1,2,3,4-tetralin-2,6-diyl, phenanthrene-2,7-diyl and fluorine-2,7-diyl groups group, wherein the groups a), b) and c) may be mono- or poly-substituted by halogen atoms, a refers to 1 or 2, preferably 1, and Z ¹ refers to -CO- in each occurrence independently of each other O-, -O-CO-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -CH ₂ -, -CH ₂ CH ₂ -, -(CH ₂ ) ₄ - , -CH=CH-CH ₂ O-, -C ₂ F ₄ -, -CH ₂ CF ₂ -, -CF ₂ CH ₂ -, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C- or a single bond, and L ¹¹ and L ¹² each independently refer to F, Cl, CF ₃ or CHF ₂ , preferably H or F, most preferably F, and One or more compounds selected from the group of compounds of formula IIA, IIB and IIC

、-C≡C-、-CF₂O-、-OCF₂-、-OC-O-或-O-CO-置換， L¹至L⁴ 各自彼此獨立地指代F、Cl、CF₃或CHF₂，Z²及Z^2' 各自彼此獨立地指代單鍵、-CH₂CH₂-、-CH=CH-、-CF₂O-、-OCF₂-、-CH₂O-、-OCH₂-、-COO-、-OCO-、-C₂F₄-、-CF=CF-、-CH=CHCH₂O-，p 指代0、1或2，q 指代0或1，且v 指代1至6。 where R ^2A , R ^2B and R ^2C each independently refer to H, an unsubstituted alkyl or alkenyl group having up to 15 C atoms, monosubstituted with CN or CF ₃ or at least monosubstituted with halogen, wherein additional , one or more of the CH ₂ groups in these groups may be such that the O atoms are not directly bonded to each other via -O-, -S-,

, -C≡C-, -CF ₂ O-, -OCF ₂ -, -OC-O- or -O-CO- substitution, L ¹ to L ⁴ each independently refers to F, Cl, CF ₃ or CHF ₂ , Z ² and Z ^2' each independently refer to a single bond, -CH ₂ CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO-, -C ₂ F ₄ -, -CF=CF-, -CH=CHCH ₂ O-, p refers to 0, 1 or 2, q refers to 0 or 1, and v refers to Generations 1 to 6.

This type of media can be specifically used for electro-optical displays with active matrix addressing based on the ECB effect and in-plane switching (IPS) displays or fringe field switching (FFS) displays.

The principle of electrically controlled birefringence (ECB) effect or deformation of aligned phases (DAP) effect was first described in 1971 (M.F.Schieckel and K.Fahrenschon, "Deformation of nematic liquid crystals with "vertical orientation in electrical fields", Appl. Phys. Lett. 19 (1971), 3912). This was followed by the paper by J.F. Kahn (Appl. Phys. Lett. 20 (1972), 1193) and the paper by G. Labrunie and J. Robert (J. Appl. Phys. 44 (1973), 4869).

-0.5之介電各向異性之值，以便適用於基於ECB效應之高資訊顯示元件。基於ECB效應之電 光顯示元件具有垂直邊緣配向(VA技術=豎直配向(vertically aligned))。介電負性液晶介質亦可用於使用所謂IPS或FFS效應之顯示器中。 Papers by J.Robert and F.Clerc (SID 80 Digest Techn.Papers (1980), 30), papers by J.Duchene (Displays 7 (1986), 3) and papers by H.Schad (SID 82 Digest Techn.Papers (1982), 244) showed that the liquid crystal phase must have a high value of the elastic constant K ₃ /K ₁ ratio, a high value of the optical anisotropy Δn and Δε

The dielectric anisotropy value of -0.5 is suitable for high information display components based on the ECB effect. Electro-optical display elements based on the ECB effect have vertical edge alignment (VA technology = vertically aligned). Dielectric negative liquid crystal media can also be used in displays using the so-called IPS or FFS effect.

Except for in-plane switching (IPS) displays (for example: Yeo, SD, Paper 15.3: "An LC Display for the TV Application", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Volume II, In addition to the well-known twisted nematic (TN) displays, such as multi-domain vertical alignment (MVA), such as Yoshide, H. et al. Paper 3.1: "MVA LCD for Notebook or Mobile PCs...", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Volume I, Pages 6 to 9, and Liu, CT et al., Paper 15.1: "A 46-inch TFT-LCD HDTV Technology...", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Volume II, pages 750 to 753), patterned vertical alignment type ( p atterned v ertical a lignment, PVA, for example: Kim, Sang Soo, paper 15.4: "Super PVA Sets New State-of-the-Art for LCD-TV", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Volume II, Pages 760 to 763), advanced super viewing angle type (ASV, for example : Shigeta, Mitzuhiro and Fukuoka, Hirofumi, paper 15.2: "Development of High Quality LCDTV", SID 2004 International Symposium, Digest of Technical Papers , Established as one of the three most important updated types of LCD displays (especially for TV applications). These techniques are described in general form in, for example, Souk, Jun, SID Seminar 2004, Seminar M-6: "Recent Advances in LCD Technology", Seminar Lecture Notes, M-6/1 to M-6/26, and Miller, Ian, SID Seminar 2004, Seminar M-7: "LCD-Television", Seminar Lecture Notes, M-7/1 to M-7/32 for comparison. Although the response time of modern ECB displays has been significantly improved by addressing methods using overdrive drivers, for example: Kim, Hyeon Kyeong et al., Paper 9.1: "A 57-in.Wide UXGA TFT-LCD for HDTV Application", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Volume I, pages 106 to 109. However, the realization of response time for video compatibility, especially regarding grayscale switching, is still a problem that has not yet been satisfactorily solved.

The industrial application of this effect in electro-optical display components requires an LC phase, which must meet various requirements. Of particular importance here is the chemical resistance to moisture, air and physical influences such as heat, infrared, visible and ultraviolet radiation as well as DC and AC electric fields.

Furthermore, an industrially usable LC phase is necessary to have a liquid crystalline mesophase within a suitable temperature range and at low viscosity.

None of the hitherto disclosed series of compounds with liquid crystalline mesophases includes a single compound that meets all of these requirements. Thus generally mixtures of two to 25, preferably three to 18 compounds are prepared to obtain materials that can be used as LC phases. However, it is not possible to easily prepare optimal phases in this way, since liquid crystal materials with significant negative dielectric anisotropy and sufficient long-term stability have not yet been obtained.

A matrix liquid-crystal display (MLC display) is known. Nonlinear elements that can be used for individual switching of individual pixels are, for example, active elements (ie, transistors). The term "active matrix" is then used, where a distinction can be made between the following two types:

1. Metal oxide semiconductor (MOS) transistor on silicon wafer as substrate

2. Thin-film transistors (TFT) on the glass plate serve as the substrate.

In the case of Type 1, the electro-optical effects used are usually dynamic scattering or guest-host effects. The use of monocrystalline silicon as a substrate material limits display size because even various partial display module assemblies create problems at the joints.

In the case of the more promising type 2, which is preferred, the electro-optical effect used is usually the TN effect.

A distinction is made between two technologies: TFTs containing compound semiconductors such as, for example, CdSe, or TFTs based on polycrystalline or amorphous silicon. The latter technique is widely used around the world.

A TFT matrix is applied inside one glass plate of the display, while the other glass plate carries transparent counter electrodes inside it. Compared with the size of pixel electrodes, TFTs are extremely small and have almost no adverse effects on images. This technology can also be extended to a fully colour-capable display, in which a mosaic of red, green and blue filters is arranged with filter elements facing each switchable pixel.

Here, the term MLC display covers any matrix display with integrated non-linear elements, that is, in addition to active matrices, it also covers displays with passive elements, such as varistors or diodes (MIM=Metal-Insulator-Metal).

This type of MLC display is particularly suitable for TV applications (such as pocket TVs) or high-information displays in automobile or aircraft construction. In addition to issues regarding the angular dependence of contrast and response time, the specific resistance of the liquid crystal mixture is not high enough in MLC displays. Difficulties also arise [TOGASHI, S., SEKIGUCHI, K., TANABE, H., YAMAMOTO, E., SORIMACHI, K., TAJIMA, E., WATANABE, H., SHIMIZU, H., Proc.Eurodisplay 84, September 1984: A 210-288 Matrix LCD Controlled by Double Stage Diode Rings, pp. 141 et seq., Paris; STROMER, M., Proc. Eurodisplay 84, September 1984: Design of Thin Film Transistors for Matrix Addressing of Television Liquid Crystal Displays, pp. 145 et seq., Paris]. As the resistance decreases, the contrast ratio of the MLC display deteriorates. Since the specific resistance of the liquid crystal mixture typically decreases with the life of the MLC display due to interaction with the inner surface of the display, high (initial) resistance is extremely important for displays that must have acceptable resistance values over long periods of operation.

There is still a large need for MLC displays with extremely high specific resistance while having a large operating temperature range, short response time and low threshold voltage, whereby a variety of grayscales can be produced.

Disadvantages of commonly used primary MLC-TN displays are due to their relatively low contrast, relatively high viewing angle dependence and the difficulty of generating grayscale in such displays.

The market for VA, PS-VA, IPS, FFS and UB-FFS applications is looking for LC mixtures with fast response times and extremely high reliability. One method for achieving fast response times is to identify highly polar LC materials with low rotational viscosities that promote the desired effect in the LC mixture. However, the use of this type of highly polar LC materials has a negative impact on reliability parameters, especially after exposure.

The present invention is based on the object of providing liquid crystal mixtures based on the ECB, UB-FFS, IPS or FFS effect, in particular for monitor and TV applications, which liquid crystal mixtures do not have the disadvantages indicated above, or only have them to a reduced extent. the shortcomings indicated above. specific language Specifically, it is necessary to ensure that monitors and TVs operate equally well at both extremely high and extremely low temperatures, with extremely short response times and at the same time improved reliability behavior, specifically without image retention or significant degradation after long periods of operation. The image remains.

Compounds of the following general formula

It is mentioned in European patent application EP 17161352.4 as a component of liquid crystal media. Also reveal the following formula

and

However, only a single compound

Used in the medium of that document, where n is 2 and m is 5.

The present invention thus relates to a liquid-crystalline medium comprising at least one compound of formula I and one or more compounds selected from the group of compounds of formulas IIA, IIB and IIC. These media are particularly suitable for enabling memory storage in liquid crystal displays that exhibit fast response times and good voltage retention, as well as excellent stability at deep temperatures sufficient for many applications.

70℃，較佳

75℃，特定言之

80℃)、極有利之電容臨限值、相 對較高之保持率值及同時在-20℃及-30℃下極佳的低溫穩定性，以及極低旋轉黏度值及較短回應時間。此外，除旋轉黏度γ₁之改良以外，根據本發明之混合物的突出之處在於可觀測到用於改良回應時間之相對較高的彈性常數K₃₃值。在LC混合物，較佳地具有負介電各向異性之LC混合物中使用式I化合物，降低旋轉黏度γ₁及彈性常數K_i之比率。 The mixtures according to the invention preferably exhibit a very broad nematic phase range (where the clear point

70℃, better

75℃, specifically

80℃), extremely favorable capacitance threshold value, relatively high retention value and excellent low temperature stability at -20℃ and -30℃, as well as extremely low rotational viscosity value and short response time. Furthermore, in addition to the improvement of the rotational viscosity γ ₁ , the mixture according to the invention is distinguished by the observable relatively high values of the elastic constant K ₃₃ for the improvement of the response time. The use of compounds of formula I in LC mixtures, preferably LC mixtures with negative dielectric anisotropy, reduces the ratio of rotational viscosity γ ₁ and elastic constant K _i .

Some preferred embodiments of mixtures according to the invention are indicated below.

In the compounds of formula I, R ¹¹ and R ¹² preferably each independently refer to: linear alkyl, in particular CH ₃ , n -C ₂ H ₅ , n -C ₃ H ₇ , n -C ₄ H ₉ , n -C ₅ H ₁₁ , n -C ₆ H ₁₃ - or n -C ₇ H ₁₅ ; linear alkoxy group, specifically CH ₃ -O, n -C ₂ H ₅ -O, n - C ₃ H ₇ -O, n -C ₄ H ₉ -O, n -C ₅ H ₁₁ -O or n -C ₆ H ₁₃ -O; in addition, alkenyl group, specifically CH ₃ =CH, CH ₃ CH =CH, CH ₃ CH=CHCH ₂ or CH ₃ CH ₂ CH=CH; branched chain alkoxy group, specifically (CH ₃ ) ₂ CH(CH ₂ ) ₃ O; and alkenyloxy group, specifically CH ₂ =CHO, CH ₂ =CH ₂ CHO, CH ₃ CH ₂ =CHCHO or O CH ₂ CH ₂ CH=CHCH ₂ O.

R ¹¹ particularly preferably refers to a straight-chain alkyl group having 1 to 7 C atoms, and R ¹² particularly preferably refers to a straight-chain alkoxy group having 1 to 6 C atoms, in particular methoxy, ethyl Oxy, propoxy, butoxy, pentyloxy or hexyloxy.

L ¹¹ and L ¹² in formula I preferably both refer to F.

The parameter "one (a)" in Formula I preferably refers to 1.

Preferred compounds of formula I present in the medium are compounds of formulas I-1 to I-3, preferably compounds of formula I-2,

wherein the parameters have the meanings given above, R ¹¹ refers to a linear alkyl group, and R ¹² preferably refers to an alkoxy group, and L ¹¹ and L ¹² preferably both refer to F.

In a preferred embodiment, the medium contains one or more compounds of formula I selected from the group of compounds of formulas IO-1 to IO-3, preferably compounds of formula IO-2.

The parameters have the meaning given above.

In another preferred embodiment, the medium contains one or more compounds of formula I selected from the group of compounds of formulas IS-1 to IS-3, preferably compounds of formula IS-2,

The parameters have the meaning given above.

In a preferred embodiment of the present invention, the medium includes one or more compounds selected from the group of compounds of formulas I-O-1 to I-O-3 and one or more compounds selected from the group of compounds of formulas I-S-1 to I-S-3. Various compounds.

For example, compounds of formula I can be prepared as described in US 2005/0258399 or WO 02/055463 A1.

The medium according to the invention preferably contains one, two, three, four or more, preferably one, two or three compounds of formula I.

1重量%，較佳

3重量%之量用於液晶介質中。尤佳為包含1至40重量%、極佳2至30重量%之一或多種式I化合物的液晶介質。 Based on the mixture as a whole, the compound of formula I is preferably

1% by weight, preferably

An amount of 3% by weight is used in liquid crystal media. Especially preferred are liquid-crystalline media containing from 1 to 40% by weight, preferably from 2 to 30% by weight, of one or more compounds of the formula I.

In a preferred embodiment, the medium contains one or more compounds of formula ^II

wherein the parameters have the same meanings as given above according to formula I, and preferably R ¹¹ and R ¹² each independently refer to an alkyl or alkoxy group having 1 to 15 C atoms, More preferably one or both of them refers to an alkoxy group, and each of L ¹¹ and L ¹² preferably refers to F.

In a preferred embodiment, the medium contains one or more compounds of formula II selected from the group of compounds of formulas ^II -O-1 to ^II -O-10, preferably compounds of formula ^II - ^O -6,

Wherein alkyl and alkyl* each independently refer to a straight-chain alkyl group having 1 to 6 C atoms, and alkenyl and alkenyl* each independently refer to a straight-chain alkenyl group having 2 to 6 C atoms. , alkoxy and alkoxy* each independently refer to a linear alkoxy group having 1 to 6 C atoms, and L ¹ and L ² each independently refer to F or Cl.

In another preferred embodiment, alternatively or additionally, the medium contains one or more compounds selected from the group of compounds of formulas II ^- O-1 to ^II -O-10, one or more compounds of formula ^{II , wherein _} The corresponding compounds I ^I -O-1 to I ^I -O-10 have the same structure, with the only exception that the bridging atom (ie, X ¹ ) is an S atom instead of an O atom.

Preferred embodiments of the liquid crystal medium according to the present invention are indicated below: a) a liquid crystal medium further comprising one or more compounds selected from the group of compounds of the formulas IIA, IIB and IIC, in which compounds of the formulas IIA and IIB, Z ² Can have the same or different meanings. In compounds of formula IIB, Z ² and Z ^2' may have the same or different meanings.

In the compounds of formulas IIA, IIB and IIC, each of R ^2A , R ^2B and R ^2C preferably refers to an alkyl group having 1 to 6 C atoms, in particular CH ₃ , C ₂ H ₅ , n -C ₃ H ₇ , n -C ₄ H ₉ , n -C ₅ H ₁₁ .

In the compounds of formulas IIA and IIB, L ¹ , L ² , L ³ and L ⁴ preferably refer to L ¹ =L ² =F, and L ³ =L ⁴ =F, in addition L ¹ =F, and L ² =Cl, L ¹ =Cl, and L ² =F, L ³ =F, and L ⁴ =Cl, L ³ =Cl, and L ⁴ =F. Z ² and Z ² ' in formulas IIA and IIB preferably each independently refer to a single bond, in addition to a -C ₂ H ₄ -bridge bond.

In formula IIB, if Z ² =-C ₂ H ₄ - or -CH ₂ O-, then Z ^2' is preferably a single bond, or if Z ^2' = -C ₂ H ₄ - or -CH ₂ O- , then Z ² is preferably a single bond. In the compounds of formula IIA and IIB, (O)C _v H _2v+1 preferably refers to OC _v H _2v+1 , in addition C _v H _2v+1 . In compounds of formula IIC, (O)C _v H _2v+1 preferably refers to C _v H _2v+1 . In compounds of formula IIC, L ³ and L ⁴ preferably each refer to F.

Preferred compounds of formula IIA, IIB and IIC are indicated below:

其中烷基及烷基* 各自彼此獨立地指代具有1至6個C原子之直鏈烷基，且烯基及烯基* 各自彼此獨立地指代具有2至6個C原子之直鏈烯基。

Where alkyl and alkyl* each independently refer to a linear alkyl group having 1 to 6 C atoms, and alkenyl and alkenyl* each independently refer to a linear alkenyl group having 2 to 6 C atoms base.

Particularly preferred mixtures according to the invention comprise one or more of the formulas IIA-2, IIA-8, IIA-14, IIA-26, II-28, IIA-33, IIA-39, IIA-45, IIA-46, IIA-47, IIA-50, IIB-2, IIB-11, IIB-16 and IIC- 1 compound.

The proportion of the compounds of formula IIA and/or IIB in the mixture as a whole is preferably at least 20% by weight.

Particularly preferred media according to the invention comprise at least one compound of formula IIC-1,

Wherein alkyl and alkyl* have the meanings indicated above, preferably in an amount of >3% by weight, specifically >5% by weight and particularly preferably in an amount of 5 to 25% by weight.

b) a liquid crystal medium further comprising one or more compounds of formula III,

指代

、

、

、

wherein R ³¹ and R ³² each independently refer to a linear alkyl, alkoxy, alkenyl, alkoxyalkyl or alkoxy group having up to 12 C atoms, and

Refers to

,

,

,

Z ³ refers to a single bond, -CH ₂ CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO-, -C ₂ F ₄ -, -C ₄ H ₈ -, -CF=CF-.

Preferred compounds of formula III are indicated below:

Where alkyl and alkyl* each independently refer to a straight-chain alkyl group having 1 to 6 C atoms.

The medium according to the invention preferably contains at least one compound of formula IIIa and/or formula IIIb.

The proportion of the compound of formula III in the mixture as a whole is preferably at least 5% by weight.

及/或

及/或

較佳呈

5重量%，特定言之

10重量%之總量。 c) Liquid-crystalline media additionally containing compounds of the formula:

and/or

and/or

Better presentation

5% by weight, specifically

10% by weight of the total.

較佳呈2至15重量%之量。 Furthermore, mixtures according to the invention comprising the following compounds (abbreviation: CC-3-V1) are preferred

Preferably it is in an amount of 2 to 15% by weight.

Preferred mixtures contain 5 to 60% by weight, preferably 10 to 55% by weight, specifically 20 to 50% by weight of the compound of the following formula (abbreviation: CC-3-V)

In addition, a mixture is preferred, which contains a compound of the following formula (abbreviation: CC-3-V)

And the compound of the following formula (abbreviation: CC-3-V1)

較佳呈10至60重量%之量。

Preferably it is in an amount of 10 to 60% by weight.

d) Liquid crystalline media additionally containing one or more tetracyclic compounds of the following formula

wherein R ^7-10 each independently has one of the meanings indicated for R ^2A in technical solution 5, and w and x each independently refer to 1 to 6.

Particularly preferred are mixtures containing at least one compound of formula V-9.

e) a liquid crystal medium further comprising one or more compounds of the formulas Y-1 to Y-6,

Wherein R ¹⁴ to R ¹⁹ each independently refers to an alkyl or alkoxy group having 1 to 6 C atoms; z and m each independently refers to 1 to 6; x refers to 0, 1, 2 or 3 .

5重量%之量。 The medium according to the invention particularly preferably contains one or more compounds of the formulas Y-1 to Y-6, preferably in the form

5% by weight.

f) a liquid crystal medium further comprising one or more fluorinated terphenyls of the formulas T-1 to T-21,

Where R refers to a straight-chain alkyl or alkoxy group with 1 to 6 C atoms, and m=0, 1, 2, 3, 4, 5 or 6 and n refers to 0, 1, 2, 3 or 4.

R preferably refers to methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy.

The medium according to the invention preferably contains terphenyls of the formulas T-1 to T-21 in an amount of 2 to 30% by weight, in particular 5 to 20% by weight.

Particularly preferred are compounds of the formulas T-1, T-2, T-4, T-20 and T-21. In these compounds, R preferably designates an alkyl group (furthermore an alkoxy group) each having from 1 to 5 C atoms. In the compounds of formula T-20, R preferably represents an alkyl or alkenyl group, in particular an alkyl group. In compounds of formula T-21, R preferably represents an alkyl group.

0.1，則聯三苯較佳地用於根據本發明之混合物中。較佳的混合物包含2至20重量%之選自T-1至T-21化合物之群的一或多種聯三苯化合物。 If the △n value of the mixture

0.1, then terphenyl is preferably used in the mixture according to the invention. Preferred mixtures contain 2 to 20% by weight of one or more terphenyl compounds selected from the group of T-1 to T-21 compounds.

g) a liquid crystal medium further comprising one or more biphenyls of the formulas B-1 to B-3,

Where alkyl and alkyl* each independently refer to a linear alkyl group having 1 to 6 C atoms, and alkenyl and alkenyl* each independently refer to a linear alkenyl group having 2 to 6 C atoms base.

5重量%。 The proportion of biphenyl of the formulas B-1 to B-3 in the mixture as a whole is preferably at least 3% by weight, in particular

5% by weight.

Among the compounds of formulas B-1 to B-3, the compound of formula B-2 is particularly preferred.

Particularly preferred biphenyl is

其中烷基^*指代具有1至6個C原子之烷基。根據本發明之介質尤佳地包含一或多種式B-1a及/或B-2c之化合物。

Where alkyl ^* refers to an alkyl group having 1 to 6 C atoms. The medium according to the invention particularly preferably contains one or more compounds of formula B-1a and/or B-2c.

h) a liquid crystal medium containing at least one compound of the formulas Z-1 to Z-7,

wherein R and alkyl have the meanings indicated above.

i) a liquid crystal medium further comprising at least one compound of the formulas O-1 to O-18,

wherein R ¹ and R ² have the meaning indicated for R ^2A . R ¹ and R ² preferably each independently represent a linear alkyl or alkenyl group.

Preferred media include one or more of the formulas O-1, O-3, O-4, O-6, O-7, O-10, O-11, O-12, O-14, O-15, O -16 and/or O-17 compounds.

Particularly preferred media contain one or more compounds selected from the group of compounds of formula O-17.

The mixture according to the invention advantageously contains compounds of the formulas O-10, O-12, O-16 and/or O-17, in particular in an amount of 5% to 30%.

Preferred compounds of formula O-10 and O-17 are indicated below:

The medium according to the invention particularly preferably contains tricyclic compounds of formula O-10a and/or formula O-10b and one or more bicyclic compounds of formulas O-17a to O-17d. The total proportion of the combination of the compound of formula O-10a and/or O-10b and one or more compounds selected from the bicyclic compound of formula O-17a to O-17d is 5% to 40%, preferably 15% to 35% .

A very preferred mixture contains compounds O-10a and O-17a:

Compounds O-10a and O-17a are preferably present in the mixture at a concentration of 15% to 35%, more preferably 15% to 25% and more preferably 18% to 22%, based on the mixture as a whole.

A very preferred mixture contains compounds O-10b and O-17a:

Compounds O-10b and O-17a are preferably present in the mixture at a concentration of 15% to 35%, more preferably 15% to 25% and even more preferably 18% to 22% based on the mixture as a whole.

A very preferred mixture contains the following three compounds:

Compounds O-10a, O-10b and O-17a are preferably present in a concentration of 15% to 35%, more preferably 15% to 25% and more preferably 18% to 22% based on the mixture as a whole. in the mixture.

Preferred mixtures contain at least one compound selected from the group of

其中R¹及R²具有上文所指示之含義。較佳地，在化合物O-6、O-7及O-17中，R¹指代分別具有1至6個或2至6個C原子之烷基或烯基，且R²指代具有2至6個C原子之烯基。

wherein R ¹ and R ² have the meanings indicated above. Preferably, in compounds O-6, O-7 and O-17, R ¹ refers to an alkyl or alkenyl group having 1 to 6 or 2 to 6 C atoms, respectively, and R ² refers to an alkyl group having 2 Alkenyl group with 6 C atoms.

Preferred mixtures contain at least one compound of the formulas O-6a, O-6b, O-7a, O-7b, O-17e, O-17f, O-17g and O-17h:

Where alkyl refers to an alkyl group having 1 to 6 C atoms.

The compounds of the formulas O-6, O-7 and O-17e-h are preferably present in an amount of 1 to 40% by weight, preferably 2 to 35% by weight and most preferably 2 to 30% by weight. in the mixture.

j) Preferred liquid crystal media according to the invention comprise one or more substances containing tetrahydronaphthyl or naphthyl units, such as, for example, compounds of the formulas N-1 to N-5,

wherein R ^1N and R ^2N each independently have the meaning indicated for R ^2A , preferably referring to a straight-chain alkyl group, a straight-chain alkoxy group or a straight-chain alkenyl group, and Z ¹ and Z ² each independently have the meanings indicated for R 2A Represents -C ₂ H ₄ -, -CH=CH-, -(CH ₂ ) ₄ -, -(CH ₂ ) ₃ O-, -O(CH ₂ ) ₃ -, -CH=CHCH ₂ CH ₂ -, -CH ₂ CH ₂ CH=CH-, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO-, -C ₂ F ₄ -, -CF=CF-, -CF=CH-, -CH =CF-, -CF ₂ O-, -OCF ₂ -, -CH ₂ - or single bond.

k) The preferred mixture includes difluorodibenzochroman compounds of formula BC, chroman compounds of formula CR, phenanthrene fluorides of formulas PH-1 and PH-2, and fluorine compounds of formulas BF-1 and BF-2. One or more compounds of the dibenzofuran group,

Among them, R ^B1 , R ^B2 , R ^CR1 , R ^CR2 , R ¹ and R ² each independently have the meaning of R ^2A . c is 0, 1 or 2, and d refers to 1 or 2. R ¹ and R ² preferably independently of each other refer to an alkyl or alkoxy group having 1 to 6 C atoms. Compounds of formula BF-1 and BF-2 should not be equated with one or more compounds of formula I.

The mixture according to the invention preferably contains compounds of the formulas BC, CR, PH-1, PH-2 and/or BF in an amount of 3 to 20% by weight, in particular in an amount of 3 to 15% by weight.

Particularly preferred compounds of formulas BC and CR are compounds BC-1 to BC-7 and CR-1 to CR-5,

Where alkyl and alkyl* each independently refer to a linear alkyl group having 1 to 6 C atoms, and alkenyl and alkenyl* each independently refer to a linear alkenyl group having 2 to 6 C atoms base.

Very preferred are one, two or three mixtures of compounds of the formulas BC-2, BF-1 and/or BF-2.

l) Preferably the mixture contains one or more indan compounds of formula In,

指代

i 指代0、1或2。 wherein R ¹¹ , R ¹² , and R ¹³ each independently refer to a straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl group having 1 to 6 C atoms, and R ¹² and R ¹³ additionally refer to Halogen, preferably F,

Refers to

i refers to 0, 1 or 2.

Preferred compounds of formula In are compounds of formulas In-1 to In-16 indicated below:

Particularly preferred are compounds of the formulas In-1, In-2, In-3 and In-4.

5重量%，特定言之5至30重量%且極佳5至25重量%之濃度用於根據本發明之混合物中。 The compounds of formula In and sub-formulas In-1 to In-16 are preferably

A concentration of 5% by weight, in particular from 5 to 30% by weight and preferably from 5 to 25% by weight, is used in the mixtures according to the invention.

m) Preferred mixtures additionally comprise one or more compounds of the formulas L-1 to L-11,

其中R、R¹及R²各自彼此獨立地具有如技術方案5中針對R^2A所指示之含義，且烷基指代具有1至6個C原子之烷基。s指代1或2。

Wherein R, R ¹ and R ² each independently have the meaning as indicated for R ^2A in technical scheme 5, and the alkyl group refers to an alkyl group having 1 to 6 C atoms. s refers to 1 or 2.

Particularly preferred are compounds of formulas L-1 and L-4, specifically L-4.

The compounds of the formulas L-1 to L-11 are preferably used in a concentration of 5 to 50% by weight, in particular 5 to 40% by weight and preferably 10 to 40% by weight.

Particularly preferred mixture concepts are indicated below: (Explain the abbreviations used in Table A Write. Here n and m each independently refer to 1 to 15, preferably 1 to 6).

The mixtures according to the invention preferably comprise - one or more compounds of formula I, in which L ¹¹ =L ¹² =F, R ¹ =alkyl and R ^1* =alkoxy; and/or -CPY-n-Om, Specifically speaking, the concentration of CPY-2-O2, CPY-3-O2 and/or CPY-5-O2 is preferably >5% based on the mixture as a whole, specifically speaking 10% to 30%, and/or - CY-n-Om, preferably CY-3-O2, CY-3-O4, CY-5-O2 and/or CY-5-O4, its concentration is preferably >5% based on the mixture as a whole, specifically 15% to 50%, and/or -CCY-n-Om, preferably CCY-4-O2, CCY-3-O2, CCY-3-O3, CCY-3-O1 and/or CCY-5-O2 , its concentration is preferably >5% based on the mixture as a whole, specifically 10% to 30%, and/or -CLY-n-Om, preferably CLY-2-O4, CLY-3-O2 and/or CLY-3-O3, its concentration is preferably >5% based on the mixture as a whole, specifically 10% to 30%.

Furthermore, preferred are mixtures according to the invention which comprise: (n and m each independently of one another designating 1 to 6.)

- Compounds of formula I, preferably compounds of formulas I-1 to I-3, namely formulas I-O-1 to I-O-3 and/or I-S-1 to I-S-3, especially LB-3-O4 and/or LB ( Compounds of S)-4-O3, the concentration range is between 1 and 20% by weight, more preferably between 2 and 15% by weight, especially between 3 and 12% by weight, and most preferably between 4 and 11% by weight. - CPY-n-Om and CY-n-Om, the concentration of which is preferably 10% to 80% of the mixture as a whole, and/or - CPY-n-Om and CK-n-F, the concentration of which is the mixture as a whole Preferably, it is 10% to 70%, and/or -CPY-n-Om and PY-n-Om, preferably CPY-2-O2 and/or CPY-3-O2 and PY-3-O2, and its concentration is The mixture as a whole is preferably 10% to 45%, and/or - CPY-n-Om and CLY-n-Om, and the concentration of the mixture as a whole is preferably 10% to 80%, and/or - CCVC -n-V, preferably CCVC-3-V, the concentration of which is preferably 2% to 10% based on the mixture as a whole, and/or -CCC-n-V, preferably CCC-2-V and/or CCC-3-V , the concentration of which is preferably 2% to 10% based on the mixture as a whole, and/or -CC-V-V, the concentration of which is preferably 5% to 50% based on the mixture as a whole.

In a particularly preferred embodiment of the present invention, the medium contains one or more compounds of the formula B-nO-Om and/or (B(S)-nO-Om, specifically compound B-2O-O5, the concentration of which is relatively The optimal range is between 2% and 8%, and the concentration of compound CC-3-V is in the range of 25% and 35%, and the concentration of compound CC-3-V1 is in the range of 8% and 12%.

The present invention also relates to an electro-optical display with active matrix addressing based on ECB, VA, PS-VA, PA-VA, IPS, PS-IPS, FFS or PS-FFS effect, which is characterized in that it contains according to technical solution 1 to The liquid crystal medium of one or more of 11 acts as a dielectric.

-20℃至

70℃，尤佳

-30℃至

80℃，極佳

-40℃至

90℃的向列相。 The liquid crystal medium according to the present invention preferably has

-20℃ to

70℃, especially good

-30℃ to

80℃, excellent

-40℃ to

Nematic phase at 90°C.

The expression "having a nematic phase" in this context means that on the one hand, no smectic phase and crystallization are observed at low temperatures at the corresponding temperatures, and on the other hand, that the self-nematic phase still does not become clear upon heating. Studies at low temperatures were carried out in a flow viscometer at the corresponding temperature and checked by storage in a test cell with a layer thickness corresponding to the electro-optical use for at least 100 hours. If the storage stability at -20°C in the corresponding test unit is 1000 hours or more, the medium is said to be stable at this temperature. At temperatures of -30°C and -40°C, the corresponding times are 500h and 250h respectively. At high temperatures, the clear point is measured in the capillary using conventional methods.

The liquid crystal mixture preferably has a nematic phase range of at least 60K and at most 30mm ² at 20°C. The flow viscosity of s ^-1 is ν ₂₀ .

The birefringence Δn value in the liquid crystal mixture is usually between 0.07 and 0.16, preferably between 0.08 and 0.13.

150mPa．s，特定言之

120mPa．s。 The liquid crystal mixture according to the invention has a Δε of -0.5 to -8.0, in particular -2.5 to -6.0, where Δε refers to the dielectric anisotropy. Rotational viscosity γ ₁ at 20℃ is better

150mPa． s, specifically

120mPa. s.

2.5V，且極佳

2.3V。 The liquid crystal medium according to the present invention has a relatively low threshold voltage (V ₀ ) value. Its optimal range is between 1.7V and 3.0V, especially

2.5V, and excellent

2.3V.

For the present invention, unless otherwise explicitly indicated, the term "threshold voltage" refers to the capacitance threshold (V ₀ ), also known as the Freedericks threshold.

In addition, the liquid crystal medium according to the present invention has a high voltage retention value in the liquid crystal cell.

Generally speaking, a liquid crystal medium with a low addressing voltage or threshold voltage exhibits a lower voltage retention than a liquid crystal medium with a higher addressing voltage or threshold voltage, and vice versa.

△ε

1.5之彼等化合物，且術語「介電負性化合物」指代△ε<-1.5之彼等化合物。在本文中，化合物之介電各向異性藉由以下步驟測定：將10%化合物溶解於液晶主體中，且測定所得混合物在至少一個測試單元中之電容，測試單元之層厚度在各情況中為20μm且在1kHz下具有垂面及沿面的表面配向。量測電壓通常為0.5V至1.0V，但始終低於所研究之各別液晶混合物之電容臨限值。 For the purposes of the present invention, the term "dielectrically positive compound" refers to compounds with Δε > 1.5, and the term "dielectrically neutral compound" refers to -1.5

△ε

1.5 for those compounds, and the term "dielectric negative compound" refers to those compounds for which Δε <-1.5. In this article, the dielectric anisotropy of a compound is determined by dissolving 10% of the compound in a liquid crystal host and determining the capacitance of the resulting mixture in at least one test cell, the layer thickness of the test cell being in each case 20μm with vertical and along-plane surface alignment at 1kHz. The measured voltage was typically 0.5V to 1.0V, but was always below the capacitance threshold of the various liquid crystal mixtures studied.

All temperature values indicated for the present invention are in °C.

The mixture according to the invention is suitable for all VA-TFT applications, such as, for example, VAN, MVA, (S)-PVA, ASV, polymer sustained VA (PSA) and polymer stabilized VA (polymer stabilized VA, PS-VA). It is also suitable for in-plane switching (IPS) and fringe field switching (FFS) applications with negative Δε.

The nematic liquid crystal mixture in the display according to the present invention usually contains two Components: A and B, themselves consisting of one or more individual compounds.

-0.5之介電各向異性。除一或多種式I化合物以外，其較佳地包含式IIA、IIB及/或IIC之化合物，此外包含一或多種式O-17化合物。 Component A has significant negative dielectric anisotropy and provides a nematic phase

-0.5 dielectric anisotropy. In addition to one or more compounds of formula I, it preferably contains compounds of formula IIA, IIB and/or IIC and furthermore one or more compounds of formula O-17.

The proportion of component A is preferably between 45% and 100%, in particular between 60% and 100%.

-0.8的一種(或多種)個別化合物。必定為，此值愈負，在作為整體之混合物中比例A愈少。 For component A, it is better to choose the Δε value

-0.8 for one (or more) individual compounds. It must be that the more negative this value is, the smaller the proportion of A in the mixture as a whole.

Component B has an obvious nematic state, and at 20°C, the flow viscosity is not greater than 30mm ² . s ^-1 , preferably no more than 25mm ² . s ^-1 .

A variety of suitable materials are known to those skilled in the art from the literature. Particularly preferred are compounds of formula O-17.

Particularly preferred individual compounds in component B have a flow viscosity of no more than 18 mm ² at 20°C. s ^-1 , preferably no more than 12mm ² . s ^-1 extremely low viscosity nematic liquid crystal.

Component B is unitropic or tautotropic nematic, has no smectic phase and can prevent the occurrence of smectic phase in the liquid crystal mixture when the temperature drops to extremely low temperatures. For example, if various highly nematic materials are added to a smectic liquid crystal mixture, the nematic state of these materials can be compared by the degree of suppression of the smectic phase achieved.

1.5之介電各向異性之化合物。此等所謂的正性化合物通常以作為整體之混合物計以

20重量%之量存在於負介電各向異性之混合物中。 The mixture may optionally also contain component C, which contains

Compounds with dielectric anisotropy of 1.5. These so-called positive compounds are usually calculated as a mixture as a whole

An amount of 20% by weight is present in the mixture of negative dielectric anisotropy.

In addition to one or more compounds of formula I, these preferably comprise 4 to 15, in particular 5 to 12 and especially <10 compounds of formula IIA, IIB and/or IIC and Depending on the situation, one or more compounds of formula O-17 are selected.

In addition to the compounds of formula I and the compounds of formulas IIA, IIB and/or IIC and optionally O-17, other ingredients can also be present, for example up to 45% of the mixture as a whole, but preferably up to 35%, specifically up to 10% of the amount exists.

The other ingredients are preferably selected from nematic or nematic protosubstances, in particular from known substances of the following categories: azobenzene oxide, benzylidene aniline, biphenyl, terphenyl, benzoic acid Phenyl ester or cyclohexyl benzoate, phenyl cyclohexanecarboxylate or cyclohexyl cyclohexanecarboxylate, phenylcyclohexane, cyclohexylbiphenyl, cyclohexylcyclohexane, cyclohexylnaphthalene, 1,4-bicyclo Hexylbiphenyl or cyclohexylpyrimidine, phenyldioxane or cyclohexyldioxane, optionally halogenated stilbene, benzyl phenyl ether, diphenyl acetylene and substituted cinnamate esters.

The most important compounds suitable as components of liquid crystal phases of this type can be characterized by the formula IV R ²⁰ -LGER ²¹ IV

where L and E each refer to a carbocyclic or heterocyclic system from the group formed by: 1,4-disubstituted benzene and cyclohexane rings, 4,4'-disubstituted biphenyl, phenyl rings Hexane and cyclohexylcyclohexane system, 2,5-disubstituted pyrimidine and 1,3-dioxane ring, 2,6-disubstituted naphthalene, dihydronaphthalene and tetrahydronaphthalene, quinazoline and tetralin Hydroquinazoline,

Or CC single bond, Q refers to halogen, preferably refers to chlorine or -CN, and R ²⁰ and R ²¹ each refer to an alkyl, alkenyl, alkyl group having up to 18, preferably up to 8 carbon atoms. Oxy, alkoxyalkyl or alkoxycarbonyloxy, or one of these groups refers to CN, NC, NO ₂ , NCS, CF ₃ , SF ₅ , OCF ₃ , F, Cl or Br .

In most of these compounds, R ²⁰ and R ²¹ are different from each other, and one of these groups is usually an alkyl or alkoxy group. Other variations of the proposed substituents are also common. Many such materials or mixtures thereof are also commercially available. All such substances can be prepared by methods known from the literature.

It will be obvious to those skilled in the art that the VA, IPS or FFS mixtures according to the present invention may also contain compounds in which, for example, H, N, O, Cl and F are replaced with corresponding isotopes.

Furthermore, polymerizable compounds (so-called reactive mesogens, RM), as disclosed for example in U.S. 6,861,107, can be added at a concentration of preferably 0.01 to 5% by weight, especially 0.2 to 2% by weight, based on the mixture. to mixtures according to the invention. These mixtures may optionally also contain initiators, as described for example in U.S. 6,781,665. Preferably an initiator (eg Irganox-1076 from BASF) is added in an amount of 0% to 1% to Mixtures containing polymerizable compounds. Mixtures of this type can be used in the so-called polymer-stabilized VA mode (PS-VA) or PSA (polymer-sustained VA), where the polymerization of reactive mesogen groups is intended to take place in the liquid crystal mixture .The prerequisite is that the liquid crystal compound of the LC host will not be polymerized under the conditions of the reactive mesogen group (that is, usually when exposed to 320 to 360 nm reaction within the wavelength range of UV). Liquid crystalline compounds containing alkenyl side chains (such as, for example, CC-3-V) do not exhibit reaction (UV polymerization) under polymerization conditions for RM.

The mixture according to the invention may additionally contain customary additives such as, for example, stabilizers, antioxidants, UV absorbers, nanoparticles, microparticles, etc.

The structure of the liquid crystal display according to the invention corresponds to common geometries as described for example in EP-A 0 240 379.

The following examples are intended to explain the invention without limiting it. Above and below, percentage information refers to weight percent; all temperatures are indicated in degrees Celsius.

Throughout the patent application, 1,4-cyclohexylene ring and 1,4-phenylene ring are depicted as follows:

Unless explicitly mentioned otherwise, a cyclohexylene ring is trans-1,4-cyclohexylene ring.

Throughout the patent applications and working examples, the structure of the liquid crystal compounds is indicated by means of abbreviations. Unless otherwise indicated, conversion to chemical formulas was performed according to Tables 1 to 3. All groups C _n H2 _n+1 , C _m H _2m+1 and C _m' H _2m'+1 or C _n H _2n and C _m H _2m respectively have in each case n, m, m' or Straight-chain alkyl or alkylene group with z C atoms. n, m, m', z each independently refers to 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, preferably 1, 2, 3, 4, 5 or 6. In Table 1, the ring elements of the respective compounds are coded, in Table 2, the bridge members are listed, and in Table 3, the meaning of the symbols indicating the left or right side chains of the compounds.

The mixture according to the invention preferably contains, in addition to one or more compounds of formula I, one or more compounds from the compounds mentioned below under Table A.

The liquid crystal mixtures which can be used according to the invention are prepared in a manner known per se. In general, it is advisable to dissolve the required amount of the component used in smaller amounts in the components constituting the main ingredient at high temperatures. It is also possible to mix solutions of the components in organic solvents, for example in acetone, chloroform or methanol, and to remove the solvent again, for example by distillation after thorough mixing.

With the help of suitable additives, the liquid crystal phase according to the invention can be modified in such a way that it can be used in any type of display disclosed so far (eg ECB, VAN, IPS, GH or ASM-VA LCD displays).

The dielectric may also contain other additives known to those skilled in the art and described in the literature, such as, for example, UV absorbers, antioxidants, nanoparticles, and free radical scavengers. For example, 0% to 15% of polychromatic dyes, stabilizers (such as, for example, phenols, hindered amine light stabilizers (HALS)) or chiral dopants may be added. Suitable stabilizers for the mixtures according to the invention are in particular those substances listed in Table C.

For example, 0% to 15% of multi-color dyes can be added. In addition, conductive salts can be added, preferably ethyldimethyldodecyl ammonium 4-hexyloxybenzoate and tetrakis tetraphenyltetraphenylborohydride. Butylammonium or complex salts of crown ethers (see, e.g., Haller et al., Mol. Cryst. Liq. Cryst., Vol. 24 , pp. 249 to 258 (1973)) in order to improve the conductivity, or substances may be added To change the dielectric anisotropy, viscosity and/or orientation of the nematic phase. Substances of this type are described, for example, in DE-A 22 09 127, 22 40 864, 23 21 632, 23 38 281, 24 50 088, 26 37 430 and 28 53 728.

The mixture according to the invention contains at least one stabilizer from Table C given below.

Table C below indicates stabilizers which may be added to the mixture according to the invention, for example, in an amount from 0 to 10% by weight, preferably from 0.001 to 5% by weight, in particular from 0.001 to 1% by weight.

Working example:

The following examples are intended to explain the invention without limiting it. In the examples, mp refers to the melting point of the liquid crystal material in degrees Celsius and C refers to the clearing point of the liquid crystal material in degrees Celsius; the boiling point temperature is designated by mp. In addition: C refers to the crystalline solid state, S refers to the smectic phase (the index refers to the phase type), N refers to the nematic state, Ch refers to the cholesteric liquid crystal phase, I refers to the isotropic phase, and _Tg refers to Glass transition temperature. The number between the two symbols indicates the conversion temperature in degrees Celsius.

The host mixture used for the determination of the optical anisotropy Δn of the compounds of formula I is the commercial mixture ZLI-4792 (Merck KGaA). The dielectric anisotropy Δε was determined using commercial mixture ZLI-2857. After adding the compound under study and extrapolating to 100% of the compounds used Physical data on the compounds under study are obtained from changes in the dielectric constant of the host mixture. Generally, 10% of the compound under study is dissolved in the bulk mixture, depending on solubility.

Unless otherwise indicated, part or percentage information indicates parts by weight or percentage by weight.

In the above and below: _Vo refers to the capacitor threshold voltage [V] at 20°C, n _e refers to the abnormal refractive index at 20°C and 589nm, and n _o refers to the ordinary refractive index at 20°C and 589nm. , △n refers to the optical anisotropy at 20°C and 589nm, ε _⊥ refers to the dielectric permittivity perpendicular to the guide at 20°C and 1kHz, ε _∥ refers to the dielectric permittivity parallel to the guide at 20°C and 1kHz. Electrical permittivity, △ε refers to the dielectric anisotropy at 20℃ and 1kHz, cl.p., T(N, I) refers to the clear point [℃], γ ₁ refers to the measurement at 20℃ Rotational viscosity [mPa. s], which is measured in a magnetic field by the rotation method, K ₁ refers to the elastic constant, "tilt" deformation at 20°C [pN], K ₂ refers to the elastic constant, "torsion" deformation at 20°C [pN] , _K3 refers to the elastic constant, "bending" deformation at 20°C [pN], and LTS refers to the low temperature stability (nematic phase), which is determined in test cells or blocks as specified.

Unless otherwise expressly indicated, in this application reference is made to, for example, the melting point T(C,N), the transition from the smectic (S) to the nematic (N) phase T(S,N) and the clearing point T(N). All values indicated for temperature of I) or cl.p. are indicated in degrees Celsius (°C). M.p. indicates melting point. Furthermore, Tg = glassy state, C = crystalline state, N = nematic phase, S = smectic phase and I = isotropic phase. The number between these symbols indicates the transfer temperature.

Unless otherwise explicitly indicated, the term "threshold voltage" in this invention refers to the capacitance threshold (V ₀ ), also known as the Frederick threshold. In an example, the optical threshold may also be indicated for 10% relative contrast (V ₁₀ ), as is commonly used.

The display used to measure the capacitive threshold voltage consists of two plane-parallel glass outer plates with a distance of 20 μm, each with an electrode layer on the inside and an unrubbed polyimide alignment layer on the top, which creates a liquid crystal Vertical edge alignment of molecules.

The display or test unit used to measure the tilt angle consists of two plane-parallel glass outer plates with a distance of 4 μm, each with an electrode layer on the inside and a polyimide alignment layer on the top, two of which are polyimide. The imine layers rub against each other antiparallelly and cause vertical edge alignment of the liquid crystal molecules.

Unless otherwise indicated, VHR was measured after 5 minutes in an oven at 20°C (VHR ₂₀ ) and at 100°C (VHR ₁₀₀ ) in a commercially available instrument model 6254 from TOYO Corporation, Japan. Unless otherwise specified, the voltages used have frequencies ranging from 1 Hz to 60 Hz.

The accuracy of VHR measurements depends on the individual VHR value. Accuracy decreases as the value decreases. The deviations commonly observed in the case of values in various magnitude ranges are compiled in the table below with their orders of magnitude.

The stability against UV irradiation was studied using a commercially available instrument "Suntest CPS" from Heraeus, Germany. Unless explicitly directed, the sealed test unit will be irradiated for between 30 minutes and 2.0 hours without additional heating. The irradiation power in the wavelength range from 300nm to 800nm is 765W/m ² V. UV "cutoff" filters with an edge wavelength of 310 nm are used in sequence to simulate the so-called window glass mode. In each series of experiments, at least four test units were studied for each condition, and individual results are indicated as the average of the corresponding individual measurements.

The reduction in voltage retention (ΔVHR) typically caused by exposure (e.g., by UV irradiation or by LCD backlighting) is measured according to the following equation (1): ΔVHR ( t ) = VHR ( t )- VHR ( t =0) (1).

To study the low temperature stability, also known as "LTS", i.e. the stability of LC mixtures in bulk against the occurrence of spontaneous crystallization or smectic phase of the individual components at low temperatures, as the case may be, each will contain A number of sealed bottles of approximately 1 g of material are stored at one or more given temperatures, usually -10°C, -20°C, -30°C and/or -40°C, and visually inspected at regular intervals to see whether phase changes are observed . Once the first of the samples exhibits a change at a given temperature, the time is noted. The time until no change was observed at the time of the last measurement is noted as the respective LTS.

A commercially available LC material characterization system model 6254 from Toyo Corporation was used, and a VHR test cell (JSR Corp., Japan) with a cell gap of AL16301 polyimide of 3.2 μm was used to measure the ion density and the resistivity was calculated based on it. . Measurement was performed after storage in an oven at 60°C or 100°C for 5 minutes.

The so-called "HTP" refers to optically active or chiral substances in LC media The helical twisting force (in μm). Unless otherwise indicated, HTP was measured in a commercial nematic LC host mixture MLD-6260 (Merck KGaA) at a temperature of 20°C.

Unless otherwise explicitly mentioned, all concentrations in this application are indicated in weight percent and refer to the corresponding mixture as a whole (without solvent) containing all solid or liquid crystalline components. Unless otherwise expressly indicated, all physical properties are determined in accordance with "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status November 1997, Merck KGaA, Germany, and are applicable at a temperature of 20°C.

The following examples of mixtures with negative dielectric anisotropy are particularly suitable for liquid crystal displays with at least one planar alignment layer, such as for example IPS and FFS displays, especially UB-FFS (=ultra-bright FFS), and also for VA displays.

Mixture Examples and Comparative Examples

Comparative mixture C1 is prepared as follows:

This mixture has a relatively poor response time, but a better VHR value of 95.7% measured at 60°C at 1V, 1Hz.

Comparative mixture C2 is prepared as follows:

This mixture exhibited improved response time compared to Comparative Example 1, primarily due to its reduced _γ1 , but exhibited a lower VHR. The measured VHR at 1Hz, 1V at 60°C is 94.2%.

Mixture M1 is prepared as follows:

Mixture M2 is prepared as follows:

A storage test at deep temperature was performed using the above mixture in a 1 ml glass bottle.

This mixture has a better VHR and at the same time an improved response time, mainly due to its better (γ ₁ /K ₁ ) value relative to CM1 as compiled in the table below.

Mixture M3 is prepared as follows:

The measured VHR at 1Hz, 1V at 60°C is 94.2%.

Mixture M4 is prepared as follows:

The measured VHR at 1Hz, 1V at 60°C is 94.3%.

Mixture M5 is prepared as follows:

The measured VHR at 1Hz, 1V at 60°C is 94.3%.

Mixture M6 is prepared as follows:

The measured VHR at 1Hz, 1V at 60°C is 93.0%.

Mixture M7 is prepared as follows:

The measured VHR at 1Hz, 1V at 60°C is 92.9%.

Mixture M8 is prepared as follows:

The VHR measured at 60°C at 1Hz, 1V is 95.4%.

Mixture M9 is prepared as follows:

The measured VHR at 1Hz, 1V at 60°C is 93.0%.

These results clearly indicate that using B(S)-nO-Om instead of B-nO-Om produces a medium with improved rotational viscosity without reducing the VHR as much.

Especially using B(S)-nO-m in combination with LB-n-Om and/or LB(S)-n-Om, the rotational viscosity of the medium can even be reduced without further sacrificing the VHR, which can be maintained constant.

Claims (14)

A liquid crystal medium characterized in that it contains one or more compounds of formula I,

wherein R ¹¹ and R ¹² each independently refer to H, an alkyl group having 1 to 15 C atoms, or an alkoxy group, wherein in addition, one or more CH ₂ groups in these groups may not contain O atoms. Directly bonded to each other independently via -C≡C-, -CF ₂ O-, -OCF ₂ -, -CH=CH-,

,

, -O-, -CO-O-, -O-CO- substitution, and where in addition one or more H atoms may be substituted by halogen, A ¹ refers to a) 1,4 on each occurrence independently of each other - cyclohexenyl or 1,4-cyclohexylene, in which one or two non-adjacent CH ₂ groups may be replaced by -O- or -S-, or b) 1,4-phenylene, in which One or two CH groups may be replaced by N, wherein the groups a) and b) may be mono- or poly-substituted by halogen atoms, Z ¹¹ refers to each other independently on each occurrence: -CO-O- , -O-CO-, -CF ₂ O-, -OCF 2 -, -CH ₂ O-, -OCH ₂ -, -CH ₂ CH _{2 -} , -(CH ₂ ) ₄ -, -CH=CH-CH ₂ O-, -C ₂ F ₄ -, -CH ₂ CF ₂ -, -CF ₂ CH ₂ -, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, - C≡C- or single bond, and each of L ¹¹ and L ¹² independently refers to F, Cl, CF ₃ or CHF ₂ , X ¹ refers to O or S, and a refers to 1 or 2, and one or more Selected from compounds of the following formula,

Where n and m each represent 1, 2, 3, 4, 5 or 6. The liquid crystal medium of claim 1, wherein the medium contains one or more compounds selected from the group of compounds of formulas I-1 to I-3,

where the parameters have the meanings given in request 1. The liquid crystal medium of claim 1 or 2, wherein it contains one or more compounds selected from the group of compounds of formulas IO-1 to IO-3:

wherein the parameters have the meanings given in request 1. The liquid crystal medium of claim 1 or 2, wherein it contains one or more compounds selected from the group of compounds of formulas IS-1 to I-SO-3:

wherein the parameters have the meanings given in request 1. The liquid crystal medium of claim 1 or 2, wherein it contains one or more compounds selected from the following formula:

Where n and m each represent 1, 2, 3, 4, 5 or 6. The liquid crystal medium of claim 1 or 2, wherein it additionally contains one or more compounds of formula IIA:

wherein R ^2A refers to H, an alkyl or alkenyl group having up to 15 C atoms that is unsubstituted, monosubstituted with CN or CF ₃ or at least monosubstituted with halogen, wherein in addition, one or more of these groups CH ₂ groups can be used in such a way that the O atoms are not directly bonded to each other via -O-, -S-,

, -C≡C-, -CF ₂ O-, -OCF ₂ -, -OC-O- or -O-CO- substitution, L ¹ and L ² each independently refer to F or Cl, Z ² refers to Single bond, -CH ₂ CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO-, -C ₂ F ₄ -, -CF=CF-, -CH=CHCH ₂ O-, p refers to 0, 1 or 2, and v refers to 1 to 6. The liquid crystal medium of claim 1 or 2, wherein it additionally contains one or more compounds of formula IIB,

wherein R ^2B represents H, an alkyl or alkenyl group having up to 15 C atoms that is unsubstituted, monosubstituted with CN or CF ₃ or at least monosubstituted with halogen, wherein in addition, one or more of these groups CH ₂ groups can be used in such a way that the O atoms are not directly bonded to each other via -O-, -S-,

, -C≡C-, -CF ₂ O-, -OCF ₂ -, -OC-O- or -O-CO- substitution, L ³ and L ⁴ each independently refer to F or Cl, Z ² and Z ^2' each independently refers to a single bond, -CH ₂ CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO-, -C ₂ F ₄ -, -CF=CF-, -CH=CHCH ₂ O-, q refers to 0 or 1, and v refers to 1 to 6. The liquid crystal medium of claim 1 or 2, wherein the medium contains one or more compounds of formula IIC,

where R ^2C represents H, an alkyl or alkenyl group having up to 15 C atoms that is unsubstituted, monosubstituted with CN or CF ₃ or at least monosubstituted with halogen, wherein in addition, one or more of these groups CH ₂ groups can be used in such a way that the O atoms are not directly bonded to each other via -O-, -S-,

, -C≡C-, -CF ₂ O-, -OCF ₂ -, -OC-O- or -O-CO- substitution, L ³ and L ⁴ each independently refer to F or Cl, Z ² and Z ^2' each independently refers to a single bond, -CH ₂ CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO-, -C ₂ F ₄ -, -CF=CF-, -CH=CHCH ₂ O-, and v refer to 1 to 6. The liquid crystal medium of claim 1 or 2, wherein the medium additionally contains one or more compounds selected from the group of compounds of formulas O-1 to O-18,

wherein R ¹ and R ² each independently have the meaning indicated for R ^2A in claim 6. The liquid crystal medium of claim 1 or 2, wherein the medium additionally contains one or more compounds selected from the group of compounds of formulas T-1 to T-21,

where R refers to a straight-chain alkyl or alkoxy group having 1 to 6 C atoms, and m=0, 1, 2, 3, 4, 5 or 6 and n refers to 0, 1, 2, 3 or 4. The liquid crystal medium of claim 1 or 2, wherein the proportion of the compound of formula I in the mixture as a whole is from 1 to 40% by weight. A use of a liquid crystal medium according to any one of claims 1 to 11, the liquid crystal medium being used in an electro-optical display. An electro-optical display with active matrix addressing, characterized in that the electro-optical display contains a liquid crystal medium as in any one of claims 1 to 11 as a dielectric. Such as the electro-optical display of claim 13, wherein the electro-optical display is VA, PSA, PA-VA, SS-VA, SA-VA, PS-VA, PALC, IPS, PS-IPS, FFS, UB-FFS, U-IPS Or PS-FFS display.