TWI803549B - Liquid-crystalline medium - Google Patents

Abstract

The invention relates to a liquid-crystalline medium which comprises at least one compound of the formula X,

and one or more compounds selected from the group of the compounds of the formulae IIA, IIB and IIC,

Description

liquid crystal medium

The invention relates to a liquid-crystalline medium comprising one or more compounds of formula X:

、

、-O-、-CO-O-、-O-CO-置換，且其中另外，一或多個H原子可經鹵素置換，且n 表示0或1，及視情況，必定較佳地，一或多種式I化合物：

wherein R ^X1 and R ^X2 each independently represent H, an alkyl or alkoxy group having 1 to 15 C atoms, wherein in addition, one or more _CH groups in these groups can make the O atoms mutually The ways of not directly connecting each other independently via -C≡C-, -CF ₂ O-, -OCF ₂ -, -CH=CH-,

,

, -O-, -CO-O-, -O-CO-, and wherein additionally, one or more H atoms may be replaced by halogen, and n represents 0 or 1, and as the case may be, it must preferably be a or more compounds of formula I:

、

、-O-、-CO-O-、-O-CO-置換，且其中另外，一或多個H原子可經鹵素置換，

在每次出現時彼此獨立地表示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 為0、1或2，較佳地0或1，Z¹ 在每次出現時彼此獨立地表示-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 各彼此獨立地表示F、Cl、CF₃或CHF₂，較佳地表示H或F，最佳地表示F， 及一或多種選自式IIA、IIB及IIC之化合物之群的化合物：

wherein R ¹¹ and R ¹² each independently represent H, an alkyl or alkoxy group having 1 to 15 C atoms, wherein in addition, one or _more CH groups in these groups can make the O atoms mutually The ways of not directly connecting each other independently via -C≡C-, -CF ₂ O-, -OCF ₂ -, -CH=CH-,

,

, -O-, -CO-O-, -O-CO-replacement, and wherein additionally, one or more H atoms may be replaced by halogen,

In each occurrence independently of each other means a) 1,4-cyclohexenyl or 1,4-cyclohexylene, in which one or two non-adjacent _CH2 groups can be replaced by -O- or -S- Displacement, b) 1,4-phenylene, where one or both CH groups can be replaced by N, c) from piperidine-1,4-diyl, 1,4-bicyclo[2.2.2]octene Base, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl and A radical of the group of fluorene-2,7-diyl groups, wherein the radicals a), b) and c) may be monosubstituted or polysubstituted by halogen atoms, a is 0, 1 or 2, preferably 0 or 1, Z ¹ each independently represents -CO-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 represent F, Cl, CF ₃ or CHF ₂ , Preferably represents H or F, most preferably represents 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 各彼此獨立地表示F、Cl、CF₃或CHF₂，Z²及Z^2' 各彼此獨立地表示單鍵、-CH₂CH₂-、-CH=CH-、-CF₂O-、-OCF₂-、-CH₂O-、-OCH₂-、-COO-、-OCO-、-C₂F₄-、-CF=CF-、-CH=CHCH₂O-，p 表示0、1或2，q 表示0或1，且v 表示1至6。 wherein R ^2A , R ^2B and _R ^2C each independently represent H, an alkyl or alkenyl group having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF or at least monosubstituted by halogen, wherein additionally, One or more _CH2 groups in these groups can be connected via -O-, -S-,

, -C≡C-, -CF ₂ O-, -OCF ₂ -, -OC-O- or -O-CO-, L ¹ to L ⁴ each independently represent F, Cl, CF ₃ or CHF ₂ , Z ² and Z ^2' each independently represent 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 represents 0, 1 or 2, q represents 0 or 1, and v represents 1 to 6.

Such media can be used in particular for electro-optic displays with active matrix addressing and IPS (In-Plane Switching) displays or FFS (Fringe Field Switching) displays based on the ECB effect.

The principle of electrically controlled birefringence, the ECB effect or also the DAP (deformation through aligned phase) 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 a paper by J.F. Kahn (Appl. Phys. Lett. 20 (1972), 1193) and a paper by G. Labrunie and J. Robert (J. Appl. Phys. 44 (1973), 4869).

-0.5之介電各向異性△ε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面邊緣配向(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。 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 ratio of elastic constant K ₃ /K ₁ , high optical anisotropy △n value and

The dielectric anisotropy △ε value of -0.5 is suitable for high-information display elements based on the ECB effect. Electro-optic display elements based on the ECB effect have homeotropic edge alignment (VA technology = vertically a aligned). Dielectrically negative liquid-crystalline media can also be used in displays using the so-called IPS or FFS effect.

In addition to IPS (coplanar switching; i n- p lane s switching) displays (for example: Yeo, SD, paper 15.3: "An LC Display for the TV Application", SID 2004 International Symposium, Digest of Technical Papers, XXXV, No. Book II, pages 758 and 759) and the well-known TN (twisted nematic; twisted nematic ) display, such as MVA (multi-domain vertical alignment; multi -domain vertical a alignment), For example: 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 6-9 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), PVA ( Patterned vertical alignment; patterned v ertical a lignment), 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), ASV (advanced large viewing angle; a advanced s upper view), for example: Shigeta, Mitzuhiro and Fukuoka, Hirofumi, paper 15.2: "Development of High Quality LCDTV ", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Volume II, Page 754 to Page 757) display using the ECB effect, such as the so-called VAN (vertically aligned nematic; vertically a aligned nematic )) displays, which have established themselves as one of the three most important newer types of liquid crystal displays (especially for television applications) today. 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, 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, but the achievement of video-compatible response time, especially regarding grayscale switching, is still an unsatisfactory problem.

The industrial application of this effect in electro-optic display elements requires an LC phase which has to meet various requirements. Here, the effects of moisture, air, and physical influences such as heat, infrared, visible light, and violet Chemical resistance to external radiation and direct and alternating electric fields) is particularly important.

In addition, industrially available LC phases are required to have a liquid crystal mesophase in a suitable temperature range and low viscosity.

The series of compounds having a liquid crystal mesophase disclosed so far does not include a single compound that meets all of these requirements. Mixtures of two to 25, preferably three to 18 compounds are thus generally prepared to obtain a substance which can be used as an LC phase. However, it is not possible to easily prepare optimal phases in this way, since no liquid-crystalline materials having a pronounced negative dielectric anisotropy and sufficient long-term stability have hitherto been obtained.

Matrix liquid crystal displays (MLC displays) are known. Non-linear 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. MOS (Metal Oxide Semiconductor) transistors on silicon wafers as substrates

2. The thin film transistor (TFT) on the glass plate is used as the substrate.

In the case of Type 1, the electro-optic effect used is usually dynamic scattering or a guest-host effect. Using monocrystalline silicon as the substrate material limits the size of the display because even the module assembly of the various parts of the display creates problems at the joints.

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

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

A TFT matrix is applied inside one glass plate of the display, while the other glass plate carries a transparent counter electrode inside it. Compared with the size of the pixel electrode, the TFT is extremely small and has almost no adverse effect on the image. This technology can also be extended to full color display (fully colour- capable display) in which a mosaic of red, green and blue filters is arranged in such a way that the filter elements are opposite each switchable pixel.

The term MLC display here covers any matrix display with integrated non-linear elements, ie besides the active matrix, the display also has passive elements such as varistors or diodes (MIM=Metal-Insulator-Metal).

MLC displays of this type are especially suitable for TV applications (such as pocket TVs) or high-information displays in automotive or aircraft construction. In addition to problems regarding the angular dependence of contrast and response time, difficulties also arise in MLC displays because the specific resistance of liquid crystal mixtures is not high enough [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. 145ff., Paris]. As the resistance decreases, the contrast of the MLC display deteriorates. High (initial) resistance is extremely important for displays that must have acceptable resistance values over long periods of operation, since the specific resistance of the liquid crystal mixture typically decreases over the lifetime of the MLC display due to interactions with the display's inner surfaces.

There is still a great need for MLC displays with a very high specific resistance while having a large operating temperature range, short response time and low threshold voltage, whereby various gray scales can be produced.

Disadvantages of the commonly used MLC-TN displays are due to their relatively low contrast ratio, relatively high viewing angle dependence and difficulty in producing gray scales in these displays.

Markets for VA, PS-VA, IPS, FFS and UB-FFS applications are looking for LC mixture with fast response time and high reliability. One approach for achieving fast response times is to identify highly polar LC materials with low rotational viscosities, the use of which in LC mixtures promotes the desired effect. However, the use of highly polar LC materials of this type has an adverse effect 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, especially for monitor and TV applications, which do not have the disadvantages indicated above, or only have the above-mentioned disadvantages to a reduced degree. The shortcomings indicated in the text. In particular, it must be ensured that monitors and televisions also work at very high and very low temperatures and at the same time have very short response times and at the same time have improved reliability characteristics, especially after long operating times without showing image retention or showing significant Reduced image sticking.

Compounds of the general formula

It is mentioned in European Patent Application No. EP 17161352.4 as a component of liquid crystal media. also revealing

and style

其中n為2及m為5。 However, only the following single compound was used in the medium of that document:

wherein n is 2 and m is 5.

The present invention therefore relates to a liquid-crystalline medium comprising at least one compound of the formula X and one or more compounds selected from the group of compounds of the formulas IIA, IIB and IIC. These media are especially suitable for obtaining liquid crystal displays for memory storage exhibiting fast response times and good voltage retention and excellent stability at temperatures deep enough for many applications.

70℃，較佳地

75℃，尤其

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℃下極好之低溫穩定性，以及極低旋轉黏度值及短回應時間。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另外在於可觀測到用於改良回應時間之相對較高彈性常數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X化合物，降低旋轉黏度γ₁及彈性常數K_i之比率。 Mixtures according to the invention preferably exhibit a very broad range of nematic phases (where the clear point

70℃, preferably

75℃, especially

80°C), extremely favorable capacitance threshold, relatively high retention value and excellent low temperature stability at both -20°C and -30°C, as well as extremely low rotational viscosity and short response time. In addition to the improvement of the rotational viscosity _γ1 , the mixtures according to the invention are also distinguished by the observable relatively high values of the elastic constant _K33 for improving the response time. The use of compounds of formula X in LC mixtures, preferably LC mixtures with negative dielectric anisotropy, lowers the ratio of rotational viscosity _γ1 to elastic constant _K1 .

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

In the compound of formula X, R ^X1 and R ^X2 preferably each independently represent: straight-chain alkyl, especially 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, especially 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, especially CH ₃ =CH, CH ₃ CH=CH, CH ₃ CH= CHCH ₂ or CH ₃ CH ₂ CH=CH; branched alkoxy, especially (CH ₃ ) ₂ CH(CH ₂ ) ₃ O; and alkenyloxy, especially CH ₂ =CHO, CH ₂ =CH ₂ CHO, CH _{3CH2 = CHCHO} or _OCH2CH2CH = _CHCH2O .

R ^X1 particularly preferably represents a straight-chain alkyl group having 1 to 7 C atoms, and R ^X2 particularly preferably represents a straight-chain alkoxy group having 1 to 6 C atoms, especially methoxy, ethoxy, propane oxy, butoxy, pentyloxy or hexyloxy.

Preferred compounds of formula X present in the medium are compounds of formula X-1 and X-2:

wherein these parameters have the respective meanings given above, and R ^X1 is preferably alkyl or alkoxy, and R ^X2 is preferably alkoxy.

Preferred compounds of formula X-1 present in the medium are compounds of formulas X-1-1 and X-1-3:

Preferred compounds of formula X-2 present in the medium are compounds of formula X-2-1 and X-2-3:

In the compound of formula I, R ¹¹ and R ¹² preferably each independently represent: straight-chain alkyl, especially 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, especially 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, especially CH ₃ =CH, CH ₃ CH=CH, CH ₃ CH= CHCH ₂ or CH ₃ CH ₂ CH=CH; branched alkoxy, especially (CH ₃ ) ₂ CH(CH ₂ ) ₃ O; and alkenyloxy, especially CH ₂ =CHO, CH ₂ =CH ₂ CHO, CH _{3CH2 = CHCHO} or _OCH2CH2CH = _CHCH2O .

R ¹¹ particularly preferably represents a straight-chain alkyl group having 1 to 7 C atoms, and R ¹² particularly preferably represents a straight-chain alkoxy group having 1 to 6 C atoms, especially methoxy, ethoxy, propoxy , butoxy, pentyloxy or hexyloxy.

Both L ¹¹ and L ¹² in Formula I preferably represent F.

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

Where these parameters have the meanings given above, R ¹¹ represents linear alkyl, and R ¹² preferably represents alkoxy, and L ¹¹ and L ¹² preferably both represent F.

In a preferred embodiment, the media comprise one or more compounds of formula I selected from the group of compounds of formulas 10-1 to 10-3, preferably compounds of formula 10-2:

wherein the parameters have the meanings given above.

In another preferred embodiment, the media comprise 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:

wherein the parameters have the meanings given above.

A more preferred compound of formula I present in the medium is a compound of formula I-4:

wherein these parameters have the meanings given above, and preferably one of R ¹¹ and R ¹² is alkoxy and more preferably both of them are alkoxy.

A more preferred compound of formula I present in the medium is a compound of formula 10-4:

wherein these parameters have the meanings given above, and preferably one of R ¹¹ and R ¹² is alkoxy and more preferably both of them are alkoxy.

A more preferred compound of formula I present in the medium is a compound of formula IS-4:

wherein these parameters have the meanings given above, and preferably one of R ¹¹ and R ¹² is alkoxy and more preferably both of them are alkoxy.

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

Compounds of formula I can be prepared as known to the expert.

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

The medium according to the invention preferably comprises 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化合物之液晶介質。 Based on the mixture as a whole, the compound of formula X is preferably

1% by weight, better

An amount of 3% by weight is used in the liquid-crystalline medium. Particular preference is given to liquid-crystalline media comprising 1 to 40% by weight, very preferably 2 to 30% by weight, of one or more compounds of the 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化合物之液晶介質。 Based on the mixture as a whole, the compound of formula I is preferably

1% by weight, better

An amount of 3% by weight is used in the liquid-crystalline medium. Particular preference is given to liquid-crystalline media comprising 1 to 40% by weight, very preferably 2 to 30% by weight, of one or more compounds of the formula I.

Preferred embodiments of the liquid-crystalline media according to the invention are indicated as follows: a) liquid-crystalline media additionally comprising one or more compounds selected from the group of compounds of the formulas IIA, IIB and IIC, in the 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 represents an alkyl group having 1 to 6 C atoms, especially CH ₃ , C ₂ H ₅ , nC ₃ H ₇ , nC ₄ H ₉ , n-C ₅ H ₁₁ .

In the compounds of formula IIA and IIB, L ¹ , L ² , L ³ and L ⁴ preferably represent L ¹ =L ² =F and L ³ =L ⁴ =F, further represent 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. In formulas IIA and IIB, Z ² and Z ^2' preferably each independently represent a single bond, further representing a -C ₂ H ₄ - bridge.

If in formula IIB, 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 compounds of formula IIA and IIB, (O)C _v H _2v+1 preferably represents OC _v H _2v+1 , further represents C _v H _2v+1 . In compounds of formula IIC, (O)C _v H _2v+1 preferably represents C _v H _2v+1 . In compounds of formula IIC, L ³ and L ⁴ preferably each represent F.

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

其中烷基及烷基* 各彼此獨立地表示具有1至6個C原子之直鏈烷基，且烯基及烯基* 各彼此獨立地表示具有2至6個C原子之直鏈烯基。

Wherein alkyl and alkyl* each independently represent straight-chain alkyl having 1 to 6 C atoms, and alkenyl and alkenyl* each independently represent straight-chain alkenyl having 2 to 6 C atoms.

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

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

A particularly preferred medium according to the invention comprises 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, especially >5% by weight and especially preferably from 5 to 25% by weight.

b) liquid-crystalline media additionally comprising one or more compounds of the formula III:

表示

、

、

、

或

wherein each of R ^{and R} independently of each other represents straight-chain alkyl, alkoxy, alkenyl, alkoxyalkyl or alkoxy having up to 12 C atoms, and

express

,

,

,

or

Z ³ represents 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:

wherein the alkyl group and the alkyl group* each independently represent a straight-chain alkyl group having 1 to 6 C atoms.

The medium according to the invention preferably comprises 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

較佳地總量為

5重量%、尤其

10重量%。 c) liquid-crystalline media additionally comprising a compound of the formula:

and/or

and/or

Preferably the total amount is

5% by weight, especially

10% by weight.

較佳地量為2至15重量%。 In addition, preference is given to mixtures according to the invention comprising the following compounds (abbreviation: CC-3-V1):

A preferred amount is 2 to 15% by weight.

A preferred mixture comprises 5 to 60% by weight, preferably 10 to 55% by weight, especially 20 to 50% by weight of a compound of the formula (abbreviation: CC-3-V):

In addition, it is preferred to comprise a compound of the following formula (abbreviation: CC-3-V):

之混合物，較佳地量為10至60重量%。 And the compound of the following formula (abbreviation: CC-3-V1):

The preferred amount is from 10 to 60% by weight.

d) Liquid-crystalline media additionally comprising one or more tetracyclic compounds of the formula:

wherein R ^7-10 each independently have one of the meanings indicated for R ^2A in claim 5, and w and x each independently represent 1 to 6.

Especially preferred are mixtures comprising at least one compound of formula V-9.

e) liquid-crystalline media additionally comprising one or more compounds of the formulas Y-1 to Y-6:

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

5重量%。 The medium according to the invention especially preferably comprises one or more compounds of the formulas Y-1 to Y-6, preferably in an amount

5% by weight.

f) liquid-crystalline media additionally comprising one or more fluorinated terphenyls of the formulas T-1 to T-21:

Wherein R represents a linear alkyl or alkoxy group having 1 to 6 C atoms, and m=0, 1, 2, 3, 4, 5 or 6, and n represents 0, 1, 2, 3 or 4.

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

The media according to the invention preferably comprise terphenyls of the formulas T-1 to T-21 in amounts of 2 to 30% by weight, especially 5 to 20% by weight.

Especially preferred are compounds of the formulas T-1, T-2, T-4, T-20 and T-21. exist In these compounds, R preferably represents an alkyl group each having 1 to 5 C atoms, further represents an alkoxy group. In compounds of formula T-20, R preferably represents alkyl or alkenyl, especially alkyl. In the compound of formula T-21, R preferably represents an alkyl group.

0.1，則聯三苯較佳用於根據本發明之混合物中。較佳混合物包含2至20重量%之一或多種選自T-1至T-21化合物之群的聯三苯化合物。 If the Δn value of the mixture

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

g) liquid-crystalline media additionally comprising one or more biphenyls of the formulas B-1 to B-3:

Wherein the alkyl group and alkyl ^* each independently represent a straight-chain alkyl group having 1 to 6 C atoms, and the alkenyl group and alkenyl ^* each independently represent a straight-chain alkenyl group having 2 to 6 C atoms.

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

5% by weight.

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

The preferred biphenyl is

其中烷基^*表示具有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。

wherein alkyl ^* represents an alkyl group having 1 to 6 C atoms. The media according to the invention particularly preferably comprise one or more compounds of the formulas B-1a and/or B-2c.

h) liquid-crystalline media comprising at least one compound of the formulas Z-1 to Z-7:

wherein R and alkyl have the meanings indicated above.

i) liquid-crystalline media additionally comprising at least one compound of the formulas O-1 to O-18:

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

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

Especially preferably comprising one or more compounds selected from the group of compounds of formula O-17.

The mixtures according to the invention very particularly preferably comprise compounds of the formulas O-10, O-12, O-16 and/or O-17, especially in amounts of 5% to 30% by weight.

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

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

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

Based on the mixture as a whole, compounds O-10a and O-17a are preferably present in an amount of 15% by weight to 35% by weight, more preferably 15% by weight to 25% by weight and especially preferably 18% by weight to 22% by weight concentration present in the mixture.

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

Based on the mixture as a whole, compounds O-10b and O-17a are preferably present in an amount of 15% by weight to 35% by weight, more preferably 15% by weight to 25% by weight and especially preferably 18% by weight to 22% by weight concentration present in the mixture.

Optimal Blend contains the following three compounds:

Based on the mixture as a whole, compounds O-10a, O-10b and O-17a are preferably present in an amount of 15% by weight to 35% by weight, more preferably 15% by weight to 25% by weight and especially preferably 18% by weight A concentration of up to 22% by weight is present in the mixture.

Preferred mixtures comprise at least one compound selected from the following group of compounds:

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表示分別具有1至6個或2至6個C原子之烷基或烯基，且R²表示具有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 represents an alkyl or alkenyl group having 1 to 6 or 2 to 6 C atoms, respectively, and R ² represents an alkyl or alkenyl group having 2 to 6 an alkenyl group with a C atom.

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

Wherein alkyl represents an alkyl group having 1 to 6 C atoms.

The compounds of formula 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 very particularly preferably 2 to 30% by weight in the mixture according to the invention.

j) Preferred liquid-crystalline media according to the invention comprise one or more substances containing tetralinyl or naphthyl units, such as compounds of the formulas N-1 to N-5:

wherein R ^1N and R ^2N each independently have the meanings indicated for R ^2A , preferably straight-chain alkyl, straight-chain alkoxy or straight-chain alkenyl, and Z ¹ and Z ² each independently represent -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 a single bond.

k) A preferred mixture comprises one or more difluorodibenzochroman compounds selected from the group consisting of formula BC, chroman of formula CR, phenanthrene fluoride of formula PH-1 and PH-2, formula BF-1 and BF-2 Compounds of the group of fluorinated dibenzofurans:

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

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

Particularly preferred compounds of formula BC and CR are compounds BC-1 to BC-7 and CR-1 to CR-5:

Wherein alkyl and alkyl* each independently represent straight-chain alkyl having 1 to 6 C atoms, and alkenyl and alkenyl* each independently represent straight-chain alkenyl having 2 to 6 C atoms.

Very particular preference is given to mixtures comprising one, two or three compounds of formula BC-2, BF-1 and/or BF-2.

l) A preferred mixture comprises one or more indane compounds of the formula In:

表示

i 表示0、1或2。 Wherein R ¹¹ , R ¹² , R ¹³ each independently represent straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl with 1 to 6 C atoms, R ¹² and R ¹³ additionally represent halogen, relatively Good for F,

express

i represents 0, 1 or 2.

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

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

5重量%、尤其5至30重量%且極尤佳5至25重量%之濃度用於根據本發明之混合物中。 Compounds of formula In and subformulas In-1 to In-16 are preferably

Concentrations of 5% by weight, especially 5 to 30% by weight and very preferably 5 to 25% by weight, are 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各彼此獨立地具有如請求項5中R^2A所指示之含義，且烷基表示具有1至6個C原子之烷基。s表示1或2。

Wherein R, R ¹ and R ² each independently have the meaning indicated by R ^2A in claim 5, and the alkyl group represents an alkyl group having 1 to 6 C atoms. s means 1 or 2.

Especially preferred are compounds of the formulas L-1 and L-4, especially L-4.

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

The concept of particularly preferred mixtures is indicated as follows: (abbreviations used are explained in Table A. Here n and m each represent independently of each other 1 to 15, preferably 1 to 6).

The mixture according to the invention preferably comprises - one or more compounds of formula X, wherein n=0, R ^X1 = alkyl and R ^X2 = alkoxy; and/or - one or more compounds of formula X, wherein n = 1 , R ^X1 = alkyl and R ^X2 = alkoxy; and/or - one or more compounds of formula I, wherein L ¹¹ =L ¹² =F, R ¹ =alkyl and R ^1* =alkoxy; and/or or - CPY-n-Om, especially CPY-2-O2, CPY-3-O2 and/or CPY-5-O2, preferably in a concentration of >5% by weight, especially 10% by weight to 30% by weight, based on the mixture as a whole % by weight, and/or - CY-n-Om, preferably CY-3-O2, CY-3-O4, CY-5-O2 and/or CY-5-O4, the concentration of which is calculated as a mixture as a whole Preferably >5% by weight, especially 15% to 50% by weight, and/or - CCY-n-Om, preferably CCY-4-O2, CCY-3-O2, CCY-3-O3, CCY-3 -O1 and/or CCY-5-O2, the concentration of which is preferably >5% by weight, especially 10% to 30% by weight, based on the mixture as a whole, and/or -CLY-n-Om, preferably CLY- The concentration of 2-O4, CLY-3-O2 and/or CLY-3-O3 is preferably >5% by weight, especially 10% to 30% by weight, based on the mixture as a whole.

In addition, preferred is the mixture according to the present invention, which comprises: (n and m represent 1 to 6 independently of each other.)

- Formula X, preferably formulas X-1 and X-2, preferably formulas XOY-n-m, XOY-n-Om, CXOY-n-m and CXOY-n-Om (especially selected from formulas XOY-3-2, XOY-3-O2 and XOY-3-O4, CXOY-3-1, CXOY-3-O2 and CXOY-3-O4 group) compound, its concentration range is 1 to 30% by weight, more preferably 2 to 25% by weight, preferably 3 to 20% by weight, and very preferably 4 to 15% by weight

- formula I, if present, preferably formulas I-1 to I-3, ie formulas I-O-1 to I-O-3 and/or I-S-1 to I-S-3, especially LB-3-O4 and/or LB The compound of (S)-4-O3 has a concentration ranging from 1 to 20% by weight, more preferably from 2 to 15% by weight, especially preferably from 3 to 12% by weight and very preferably from 4 to 11% by weight

- CPY-n-Om and CY-n-Om, preferably in a concentration of 10% to 80% by weight of the mixture as a whole, and/or

- CPY-n-Om and CK-n-F, preferably at a concentration of 10 based on the mixture as a whole % by weight to 70% by weight, and/or

- CPY-n-Om and PY-n-Om, preferably CPY-2-O2 and/or CPY-3-O2 and PY-3-O2, preferably in a concentration of 10% by weight to 45% by weight of the mixture as a whole weight%, and/or

- CPY-n-Om and CLY-n-Om, preferably in a concentration of 10% to 80% by weight of the mixture as a whole, and/or

- CCVC-n-V, preferably CCVC-3-V, preferably in a concentration of 2% to 10% by weight, based on the mixture as a whole, and/or

- CCC-n-V, preferably CCC-2-V and/or CCC-3-V, preferably in a concentration of 2% to 10% by weight, based on the mixture as a whole, and/or

- CC-V-V, preferably in a concentration of 5% to 50% by weight of the mixture as a whole.

In a particularly preferred embodiment of the present invention, the medium comprises one or more compounds selected from the group of compounds of formula XOY-n-Om and CXOY-n-Om in a concentration range of 2% to 15% by weight and concentrations Compound CC-3-V in the range of 25% to 40% by weight and compound CC-3-V1 in the concentration range of 5% to 12% by weight.

In a particularly preferred embodiment of the present invention, the medium comprises compounds B-2O-O5 and/or B-2O-O5 and/or B-5O-O5 in a concentration range of 2% to 8% by weight and a concentration range of Compound CC-3-V within 25% to 40% by weight and concentration range from 5% to 12% by weight % compound CC-3-V1.

In a particularly preferred embodiment of the present invention, the medium comprises compounds B(S)-2O-O4 and/or B(S)-2O-O5 and/or B( S)-2O-O6 and compound CC-3-V in the concentration range of 25% to 40% by weight and compound CC-3-V1 in the concentration range of 5% to 12% by weight.

The invention furthermore relates to an electro-optic display with active matrix addressing based on the ECB, VA, PS-VA, PA-VA, IPS, PS-IPS, FFS or PS-FFS effect, which contains the following claims 1 to 11 One or more liquid crystal media are used as dielectrics.

-20℃至

70℃、尤佳

-30℃至

80℃、極尤佳

-40℃至

90℃。 The nematic phase of the liquid-crystalline medium according to the invention is preferably

-20°C to

70℃, preferably

-30°C to

80℃, very good

-40°C to

90°C.

The expression "having a nematic phase" means in this context that, on the one hand, no smectic phase and no crystallization are observed at low temperatures at corresponding temperatures, and, on the other hand, no clearing phenomenon occurs from the nematic phase when heated. The studies at low temperature 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-optic use for at least 100 hours. A medium is said to be stable at a temperature of -20°C if it has a storage stability of 1000 hours or more in the corresponding test unit at a temperature of -20°C. At temperatures of -30°C and -40°C, the corresponding times are 500 hours and 250 hours, respectively. The clear point is measured by known methods in capillaries at high temperature.

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

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

150mPa．s，尤其

120mPa．s。 The Δε of the liquid-crystal mixtures according to the invention is from -0.5 to -8.0, especially from -2.5 to -6.0, where Δε denotes the dielectric anisotropy. Rotational viscosity at 20°C γ ₁ is better

150mPa． s, especially

120mPa． s.

2.5V且極尤佳為

2.3V。 The liquid-crystalline media according to the invention have relatively low threshold voltage (V ₀ ) values. It is preferably in the range of 1.7V to 3.0V, especially the

2.5V and very preferably as

2.3V.

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

In addition, the liquid-crystalline media according to the invention have high voltage retention values in liquid-crystal cells.

In general, a liquid crystal medium with a low addressing voltage or threshold voltage exhibits a lower voltage retention ratio 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」表示△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重量%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下為20μm且在1kHz下具有垂面及均質表面配向。量測電壓通常為0.5V至1.0V，但總低於所研究之各別液晶混合物之電容臨限值。 For the present invention, the term "dielectrically positive compound" means a compound with △ε>1.5, and the term "dielectrically neutral compound" means -1.5

△ε

1.5, and the term "dielectric negative compound" means those compounds where △ε<-1.5. In this context, the dielectric anisotropy of the compounds is determined by dissolving 10% by weight 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 which is in each case It is 20 μm and has homeotropic and homogeneous surface alignment at 1 kHz. The measurement voltage is typically 0.5 V to 1.0 V, but always below the capacitance threshold of the respective liquid crystal mixture studied.

All temperature values indicated with respect to the present invention are in °C.

The mixtures according to the invention are suitable for all VA-TFT applications such as VAN, MVA, (S)-PVA, ASV, PSA (polymer maintained VA) and PS-VA (polymer stabilized VA). It is additionally suitable for IPS (In-Plane Switching) and FFS (Fringe Field Switching) applications with negative Δε.

The nematic liquid-crystal mixtures in the displays according to the invention generally comprise two components: A and B, which themselves consist of one or more individual compounds.

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

Dielectric anisotropy of -0.5. It preferably comprises, in addition to one or more compounds of formula X, compounds of formula IIA, IIB and/or IIC, additionally one or more compounds of formula O-17.

The proportion of component A is preferably between 45% by weight and 100% by weight, especially between 60% by weight and 100% by weight.

-0.8之一種(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 value of △ε

- 0.8 of one (or more) individual compounds. It must be that the more negative this value is, the less proportion A is 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 not greater than 25mm ² . s ^-1 .

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

Particularly preferred individual compounds in component B have a fluid viscosity of not more than 18 mm ² at 20°C. s ^-1 , preferably not greater than 12mm ² . s ^-1 very low viscosity nematic liquid crystal.

Component B is monotropic or tautotropic nematic, has no smectic phase and can prevent the appearance of smectic phase in the liquid crystal mixture when the temperature is reduced to very low. For example, if various high nematic materials are added to a smectic liquid crystal mixture, the nematic states of these materials can be compared via 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 a component C comprising

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

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

In addition to one or more compounds of formula X, the phases preferably comprise 4 to 15, Especially 5 to 12 and especially <10 compounds of the formulas IIA, IIB and/or IIC and optionally one or more compounds of the formula O-17.

In addition to the compound of formula X and the compound of formula IIA, IIB and/or IIC and optionally O-17, other components can also, for example, be up to 45% by weight of the mixture as a whole, but preferably up to 35% by weight, especially up to An amount of 10% by weight is present.

The other constituents are preferably selected from nematic or nematic primordium substances, especially from known substances of the following classes: oxyazobenzene, benzylidene aniline, biphenyl, terphenyl, phenyl benzoate or cyclohexyl benzoate, phenyl cyclohexanecarboxylate or cyclohexylcyclohexylcarboxylate, phenylcyclohexane, cyclohexylbiphenyl, cyclohexylcyclohexane, cyclohexylnaphthalene, 1,4-bicyclohexylbiphenyl Benzene or cyclohexylpyrimidine, phenyldioxane or cyclohexyldioxane, optionally halogenated stilbene, benzylphenyl ether, tolan and substituted cinnamate.

The most important compounds suitable as constituents of liquid crystalline phases of this type can be characterized by the following formula IV: R ²⁰ -LGER ²¹ IV

where L and E each represent a carbocyclic or heterocyclic ring system from the group formed by: 1,4-disubstituted benzene ring and cyclohexane ring, 4,4'-disubstituted biphenyl, phenylcyclohexane Alkanes and cyclohexylcyclohexane systems, 2,5-disubstituted pyrimidines and 1,3-dioxane rings, 2,6-disubstituted naphthalene, dihydronaphthalene and tetrahydronaphthalene, quinazoline and tetrahydro Quinazoline, G means -CH=CH- -N(O)=N-

-CH=CQ- -CH=N(O)-

-C≡C- -CH ₂ -CH ₂ -

-CO-O- -CH ₂ -O-

-CO-S- -CH ₂ -S-

-CH=N- -COO-Phe-COO-

-CF ₂ O- -CF=CF-

-OCF ₂ - -OCH ₂ -

-(CH ₂ ) ₄ - -(CH ₂ ) ₃ O-

or CC single bond, Q represents halogen, preferably represents chlorine or -CN, and R ²⁰ and R ²¹ each represent an alkyl group, alkenyl group, alkoxy group, alkane group having at most 18, preferably at most 8 carbon atoms Oxyalkyl or alkoxycarbonyloxy, or one of these groups, represents CN, NC, NO ₂ , NCS, CF ₃ , SF ₅ , OCF ₃ , F, Cl or Br.

In most of these compounds, ^R20 and ^R21 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. A variety of such materials or mixtures thereof are also commercially available. All these substances can be prepared by methods known from the literature.

It is self-evident for those skilled in the art that the VA, IPS or FFS mixtures according to the invention may also comprise, for example, compounds in which H, N, O, Cl and F have been replaced isotopically.

Polymerizable compounds, such as so-called reactive mesogens (RM) as disclosed in U.S. 6,861,107, can additionally be added to the mixture according to the invention, preferably in a concentration of 0.01 to 5% by weight, based on the mixture, especially preferably 0.2 to 2% by weight. Such mixtures may also optionally contain an initiator, as described, for example, in U.S. 6,781,665. Preferably an initiator, such as Irganox-1076 from BASF, is added to the mixture comprising the polymerizable compound in an amount of 0% to 1% by weight. Mixtures of this type can be used in so-called polymer-stabilized VA modes (PS-VA) or PSAs (polymer-sustained VA) in which the polymerization of reactive mesogens is intended to take place in liquid-crystalline mixtures. The prerequisite is that the liquid crystal compound of the LC host will not be in the reactive mesogen group The reaction takes place under the polymerization conditions (ie, typically upon exposure to UV in the wavelength range of 320 to 360 nm). Liquid crystal compounds containing alkenyl side chains (such as CC-3-V) do not show reaction under the polymerization conditions for RM (UV polymerization).

The mixtures according to the invention may additionally comprise conventional additives such as stabilizers, antioxidants, UV absorbers, nanoparticles, microparticles and the like.

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

The following examples are intended to illustrate the invention without limiting it. Above and below, percentage data represent percentages by weight; all temperatures are in degrees Celsius.

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

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

Throughout the patent application and the examples, the structure of the liquid crystal compounds is indicated by means of abbreviations. Conversions to chemical formulas were performed according to Tables 1 to 3 unless otherwise indicated. All radicals C _n H _2n+1 , C _m H _2m+1 and C _m' H _2m'+1 or C _n H _2n and C _m H _2m have n, m, m' or z in each case respectively C-atom straight-chain alkyl or alkylene. n, m, m', z each independently represent 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, preferably represent 1, 2, 3, 4, 5 or 6. In Table 1, the ring elements of the respective compounds are coded, in Table 2, the bridging members are listed, and in Table 3, the meanings of the symbols indicating the left or right side chains of the compounds are indicated.

In addition to one or more compounds of formula X, the mixtures according to the invention preferably comprise one or more of the compounds mentioned from Table A below.

Table A uses the following abbreviations: (n, m, m', z: each independently of each other is 1, 2, 3, 4, 5 or 6; (O)C _m H _2m+1 means OC _m H _{2m+ 1} or C _m H _2m+1 )

The liquid-crystal mixtures which can be used according to the invention are prepared in a manner known per se. In general, it is desirable to dissolve the desired amount of the component used in the smaller amount in the component constituting the main component at elevated temperature. 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 aid of suitable additives, the liquid-crystalline phases according to the invention can be modified such that they can be used in displays of any type (eg ECB, VAN, IPS, GH or ASM-VA LCD) disclosed so far.

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

For example, 0% to 15% by weight of pleochroic dyes can be added, and conductive salts can be added, preferably ethyl dimethyl dodecyl ammonium 4-hexyloxybenzoate, tetraphenyl borohydride Complex salts of tetrabutylammonium or crown ethers (see, for example, Haller et al., Mol. Cryst. Liq. Cryst., Vol. 24 , pp. 249 to 258 (1973)) to improve conductivity, or can Substances are added to modify the dielectric anisotropy, viscosity and/or alignment 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 mixtures according to the invention comprise at least one stabilizer from Table C given below.

Table C Stabilizers that can be added, for example to mixtures according to the invention, in amounts of 0 to 10% by weight, preferably 0.001 to 5% by weight, especially 0.001 to 1% by weight, are indicated below.

Example:

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

The host mixture used to determine the optical anisotropy Δn of the compound of formula X is the commercially available mixture ZLI-4792 (Merck KGaA). The dielectric anisotropy Δε was determined using a commercially available mixture ZLI-2857. The physical data of the compounds under study were obtained from the bulk mixture after addition of the compounds under study Variation of the dielectric constant of the substance and extrapolation to 100% by weight of the compound used. In general, 10% by weight of the compound to be studied is dissolved in the host mixture, depending on solubility.

Parts or percentage data represent parts or percentages by weight unless otherwise indicated.

In the above and below: V _o represents the capacitive threshold voltage [V] at 20°C, _ne represents the extraordinary refractive index at 20°C and 589nm, n _o represents the ordinary refraction at 20°C and 589nm Δn represents the optical anisotropy at 20°C and 589nm, ε _⊥ represents the dielectric permittivity perpendicular to the director at 20°C and 1kHz, ε _∥ represents the dielectric permittivity perpendicular to the director at 20°C and 1kHz Parallel dielectric permittivity, △ε represents the dielectric anisotropy at 20°C and 1kHz, cl.p. and T(N,I) represent the clear point [°C], _γ1 refers to the dielectric anisotropy at 20°C Measurement of rotational viscosity [mPa. s], which is measured in a magnetic field by the rotational method, K ₁ represents the elastic constant, the "tilt" deformation at 20°C [pN], K ₂ represents the elastic constant, the "twist" deformation at 20°C [pN] , K ₃ denotes the elastic constant, the "bending" deformation [pN] at 20° C., and LTS denotes the low temperature stability (nematic phase) as specified in the test unit or as a whole.

Unless expressly stated otherwise, references in this application to temperatures (such as melting point T(C,N), transition from smectic (S) phase to nematic (N) phase T(S,N) and clearing point T(N ,I) or cl.p.) All values indicated are indicated in degrees Celsius (°C). M.p. means melting point. In addition, Tg=glassy state, C=crystalline state, N=nematic phase, S=smectic phase and I=isotropic phase. Among these symbols The numbers between represent the transition temperature.

Unless expressly indicated otherwise, the term "threshold voltage" used in the present invention relates to the capacitance threshold (V ₀ ), also known as the Freedericks threshold. In an example, an optical threshold (V ₁₀ ) may also be indicated for 10% relative contrast, as commonly used.

The display for measuring capacitive threshold voltage consists of two plane-parallel glass outer plates with a distance of 20 μm, each with an electrode layer on the inner side and an unrubbed polyimide alignment layer on top, which realizes liquid crystal molecules vertical edge alignment.

The display or test unit for measuring the tilt angle consists of two plane-parallel glass outer plates with a distance of 4 μm, each with an electrode layer on the inner side and a polyimide alignment layer on top, where two polyimide The amine layers are rubbed antiparallel to each other and achieve vertical edge alignment of the liquid crystal molecules.

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

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

Stability to UV irradiation was studied in a commercial instrument "Suntest CPS" from Heraeus, Germany. Sealed test units were irradiated for 30 minutes to 2.0 hours without additional heating unless expressly indicated. The irradiation power for wavelengths in the range of 300 nm to 800 nm was 765 W/m ² V. A UV "cut-off" filter with an edge wavelength of 310 nm was 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 mean values corresponding to individual measurements.

The decrease in voltage retention (△VHR) usually caused by exposure (for example, by UV irradiation or by LCD backlight) is determined according to the following equation (1): △ VHR ( t ) = VHR ( t ) - VHR ( t = 0) (1).

In order to study the low-temperature stability, also known as "LTS", that is, the stability of the LC mixture in the whole against the spontaneous crystallization or smectic phase of individual components at low temperatures, depending on the specific circumstances, each will contain about 1g Several sealed bottles of material were stored at one or more given temperatures, typically -10°C, -20°C, -30°C, and/or -40°C, and inspected visually at regular intervals to see if a phase change was observed. Time is noted once the first sample exhibits a change at a given temperature. The time until the last test when no change was observed is noted as the respective LTS.

The ion density was measured using a commercially available LC material characteristic measurement system model 6254 from Toyo Corporation, Japan, using a VHR test cell of AL16301 polyimide (JSR Corp., Japan) with a cell gap of 3.2 μm, from which the resistivity was calculated . Measurements were performed after storage at 60°C or in an oven at 100°C for 5 min.

The so-called "HTP" stands for optically active or helical twisting force (in μm) for chiral substances in LC media. Unless otherwise indicated, HTP is sold at 20°C The nematic LC host mixture MLD-6260 (Merck KgaA) was sold for measurement.

Unless expressly stated otherwise, all concentrations in this application are indicated in percent by weight and relate to the corresponding mixture as a whole comprising all solid or liquid-crystalline components (solvent-free). All physical properties are determined according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status November 1997, Merck KGaA, Germany and apply at a temperature of 20°C, unless expressly indicated otherwise.

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

Mixture Examples and Comparative Examples Comparative mixture C1 was prepared as follows: (MDA-16-1989)

This mixture has the best possible response time, for the highest achievable VHR value, giving medium response time but very high VHR value.

Comparative mixture C2 was prepared as follows:

This mixture has a good balance between VHR and response time.

Mixture M1 was prepared as follows: (MDA-17-372)

Mixture M2 was prepared as follows:

Mixture M3 was prepared as follows:

Mixture M4 was prepared as follows:

Comparative mixture C3 was prepared as follows:

This mixture exhibited improved response time compared to Comparative Example 1, mainly due to its reduced _γ1 , but exhibited a lower VHR.

Mixture M5 was prepared as follows:

Mixture M6 was prepared as follows:

Mixture M7 was prepared as follows:

Mixture M8 was prepared as follows:

Mixture M9 was prepared as follows:

Claims (16)

A liquid crystal medium, characterized in that it comprises: one or more compounds of formula X:

wherein R ^X1 and R ^X2 each independently represent H, an alkyl or alkoxy group having 1 to 15 C atoms, wherein in addition, one or more _CH groups in these groups may each independently After -C≡C-, -CF ₂ O-, -OCF ₂ -, -CH=CH-,

,

, -O-, -CO-O-, -O-CO- such that the O atoms are not directly connected to each other, and wherein additionally, one or more H atoms may be replaced by halogen, and n represents 0 or 1, and One or more compounds selected from the group of compounds of formulas IIA, IIB and IIC:

wherein R ^2A , R ^2B and R ^2C each independently represent H, unsubstituted, monosubstituted with CN or CF ₃ or at least monosubstituted with halogen, alkyl or alkenyl having up to 15 C atoms, wherein in addition, One or more _CH2 groups in these groups can be connected via -O-, -S-,

, -C≡C-, -CF ₂ O-, -OCF ₂ -, -OC-O- or -O-CO-, L ¹ to L ⁴ each independently represent F or Cl, Z ² and Z ^{2 '} each independently represents 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 represents 0, 1 or 2, q represents 0 or 1, and v represents 1 to 6. The liquid crystal medium as claimed in item 1, wherein the medium further comprises one or more compounds of formula I:

wherein R ¹¹ and R ¹² each independently represent H, an alkyl or alkoxy group having 1 to 15 C atoms, wherein in addition, one or _more CH groups in these groups can make the O atoms mutually The ways of not being directly connected are each independently via -C≡C-, -CF ₂ O-, -OCF ₂ -, -CH=CH-,

,

, -O-, -CO-O-, -O-CO-replacement, and wherein additionally, one or more H atoms may be replaced by halogen,

In each occurrence independently of each other means a) 1,4-cyclohexenyl or 1,4-cyclohexylene, in which one or two non-adjacent _CH2 groups can be replaced by -O- or -S- Displacement, b) 1,4-phenylene, where one or both CH groups can be replaced by N, c) from piperidine-1,4-diyl, 1,4-bicyclo[2.2.2]octene Base, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl and A radical of the group of terpene-2,7-diyl groups, wherein the radicals a), b) and c) may be monosubstituted or polysubstituted by halogen atoms, and ^Z represent each occurrence independently of each other -CO -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 represent F, Cl, CF ₃ or CHF ₂ , X ¹ represents O or S, and a represents 1 or 2 . The liquid crystal medium as claimed in item 2, wherein the medium comprises one or more compounds selected from the group of compounds of formulas I-1 to I-3:

Wherein these parameters have the meanings given in Claim 2. The liquid crystal medium as claimed in item 2, wherein it comprises one or more compounds selected from the group of compounds of formulas IO-1 to IO-3:

Wherein these parameters have the meanings given in Claim 2. The liquid crystal medium as claimed in item 2, wherein it comprises one or more compounds selected from the group of compounds of formula IS-1 to I-SO-3:

Wherein these parameters have the meanings given in Claim 2. The liquid crystal medium as claimed in item 1 or 2, wherein it comprises one or more compounds of formula IIA:

wherein these parameters have the meanings given in Claim 1. The liquid crystal medium as claimed in item 1 or 2, wherein it additionally comprises one or more compounds of formula IIB:

wherein these parameters have the meanings given in Claim 1. The liquid crystal medium as claimed in item 1 or 2, wherein the medium comprises one or more compounds of formula IIC:

wherein these parameters have the meanings given in Claim 1. The liquid crystal medium as claimed in item 1 or 2, wherein the medium additionally comprises one or more compounds selected from the group of compounds of formulas O-1 to O-18:

wherein each of ^R1 and ^R2 independently of each other has the meanings indicated for ^R2A in claim 1. The liquid crystal medium as claimed in item 1 or 2, wherein the medium additionally comprises one or more compounds selected from the group of compounds of formulas T-1 to T-21:

Wherein R represents a linear alkyl or alkoxy group having 1 to 6 C atoms, and m=0, 1, 2, 3, 4, 5 or 6, and n represents 0, 1, 2, 3 or 4. The liquid crystal medium according to claim 1 or 2, wherein the proportion of the compound of formula X in the mixture as a whole is 1 to 40% by weight. The liquid crystal medium as claimed in item 1 or 2, wherein the compounds of formulas IIA to IIC are taken as a whole The proportion in the medium is in the range of 10% by weight to 70% by weight. A method for preparing a liquid-crystalline medium as claimed in any one of claims 1 to 12, characterized in that one or more compounds of formula X and one or more compounds selected from the group of compounds of formulas IIA to IIC and optionally present One or more compounds of the formula I are mixed. A use of the liquid crystal medium according to any one of claims 1 to 12 in an electro-optic display. An electro-optic display with active matrix addressing, characterized in that it contains a liquid crystal medium according to any one of claims 1 to 12 as a dielectric. The electro-optic display of claim 15, wherein the electro-optic 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.