JPH101672A - Supertwisted liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the subject display using a specific nematic liquid crystal mixture, having a short switching time and simultaneously having a wide practical temperature range, a high characteristic curved line steep degree, a good contrast angle dependency and a low threshold voltage. SOLUTION: This supertwisted liquid crystal display uses a nematic liquid crystal mixture having a nematic phase range of >=65 deg.C, a viscosity of <=35mPa.s and a threshold voltage of <=1.75V and comprising (A) 20-90wt.% of a liquid crystal component containing 20-40wt.% of a compound of formula I [R<1> is a 1-8C alkyl; L is H, F; (m) is 0, 1] and a compound having a dielectric anisotropy value of >=+1.5, (B) a liquid crystal component containing 15-35wt.% of a compound of formula II [R<2> is H, 1-8C alkyl; R<3> is a 1-8C (oxa)alkyl, etc.; (n) is (m)] and a compound having a dielectric anisotropic value of -1.5 to +1.5 and (C) an optically active component in such an amount that the ratio of a layer thickness (a distance between outside plates whose surfaces are parallel to each other) to the natural pitch of the liquid crystal mixture is 0.2-1.3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to supertwisted liquid crystal displays (STN displays) having short switching times, good steepness and low threshold voltage, and to novel nematic liquid crystal mixtures used therein.

[0002]

2. Description of the Related Art A title-like STN display is an example.
For example, European Patent EP 0,131,216 B1,
German Patent DE 3,423,993 A1, European
Patent EP 0,098,070 A2, 17th Fra
The M.I.Iburg liquid crystal conference (8-10.4.87) Sc
Hadt and F.M. Leenhouts, K .; Kawas
aki, etc .: “SID 87 Digest” 391
(20.6), M.P. Schadt and F.S. Leenho
uts: “SID 87 Digest” 372 (2
0.1); Katoh et al .: Journal of Japan Society of Applied Physics 2
Vol. 11; L1784-L1786 (198
7), F.R. Leenhouts et al .: "Appl. Ph.
ys. Lett. "50(21), 1468 (19
87); A. van Sprang and H.M. G. FIG. K
opman: "J. Appl. Phys."62
(5), 1734 (1987); J. Scheff
er and J.A. Nehring: "Appl. Phys.
s. Lett. "45(10), 1021 (198)
4), M.P. Schadt and F.S. Leenhouts:
"Appl. Phys. Lett."50
(5), 236 (1987); P. Rayne
s: "Mol. Cryst. Liq. Crys.
t. Letters "Vol.4 (1), pp1-
8 (1986). Here, STN is 16
0^o And 720^o Relatively with a twist angle with a value between
Including any display elements that are strongly twisted
Display elements such as Waters [C.
M. Waters et al .: "Proc. Soc. Inf. D.
isp. "(New York) (1985) (Kobe, Japan)
3rd International Display Conference in Japan)], STN-Liquid
Crystal display (German Patent DE OS 3,503,
259), SBE-liquid crystal display [T. J. Sch
effer and J.M. Nehring: "Appl. P
hys. Lett. "45 (1984) 102
1], OMI-liquid crystal display [M. Schadt and
And F. Leenhouts: "Appl. Phys.
 Lett. 50 (1987), 236], DST
Liquid crystal displays (European patent EP OS 0,
246,842) or BW-STN-liquid crystal display
[K. Kawasaki et al .: "SID 87 Dige
st "391 (20.6)].

[0003]

Compared to a standard TN display, this type of STN display has a very good steepness of the electro-optical properties and a good contrast value associated therewith, and this contrast is very low. Outstanding due to very low angle dependence. Of particular interest are STN displays that have short switching times, even at relatively low temperatures. In order to achieve short switching times, among others, the viscosity of the liquid-crystal mixtures is conventionally determined, in general, by using an optimized combination of the respective liquid-crystal components, and optionally also by the use of mono-modified additives with a relatively high vapor pressure. It was optimized by use. However, the achieved switching times were not suitable for all applications.

[0004] The shorter switching time is also due to its S
It can also be achieved by reducing the thickness of the liquid crystal layer of the TN display and using a liquid crystal mixture having a higher birefringence Δn.

[0005] In general, compositions having short switching times have relatively high threshold voltages.

However, all means for achieving such shorter switching times have only led to mixtures which are not suitable for all applications, in particular those having a high threshold voltage.

[0007] International patent application WO 95/30723 has relatively short switching times and high threshold voltages.
The following formula

[0008]

Embedded image Describes STN displays based on the following compound:

However, there is a need to improve such a threshold voltage.

[0010] Further, higher multiplexing capability, lower threshold voltage and steep characteristic curves are further required for STN displays.

However, it is not possible to achieve optimal parameters for all the properties mentioned above at the same time because of the conflicting effects of different material property parameters, such as dielectric properties and viscoelastic properties.

Thus, there is still a great need for improved STN displays having a short operating time, a wide operating temperature range, a high characteristic curve steepness, a good angle dependence of the contrast and a low threshold voltage. .

It is an object of the present invention to provide an STN display which has the above-mentioned disadvantages to a small extent or not at all, and at the same time has very useful overall properties.

[0014]

Means for Solving the Problems The present inventors have made the following formulas I, II1 and II2

[0015]

Embedded image Wherein R ¹ is alkyl having 1 to 8 carbon atoms, m is 0 or 1, and
Is H or F]

[0016]

Embedded image Wherein R ² is H or alkyl having 1 to 8 carbon atoms, and R ³ is alkyl, oxaalkyl or alkenyl having up to 8 carbon atoms. It has been found that the above object can be achieved when a nematic liquid crystal mixture containing two or more mixtures is used.

The nematic liquid crystal mixture preferably has a nematic phase temperature range of at least 60 ° C., 35 mPa · s
It has a viscosity no higher than s and a dielectric anisotropy of at least +8, wherein the dielectric anisotropy of the compounds and the parameters of the nematic liquid-crystal mixture are for a temperature of 20 ° C.

Accordingly, the present invention provides: two plane-parallel outer plates forming a cell together with a frame; a nematic liquid crystal mixture having a positive dielectric anisotropy present in the cell; A pretilt angle between about 1 degree and 30 degrees between each outer plate and the longitudinal axis of each molecule at the surface of these outer plates; and Of the liquid crystal mixture in the
Supertwisted liquid crystal displays having a twist angle having a value between 00 ^° and 600 ^° , wherein the nematic liquid crystal mixture comprises: a) 20 to 90% by weight of a dielectric anisotropy of more than +1.5 B) 10 to 65% by weight of a liquid crystal component B comprising one or more compounds having a dielectric anisotropy from -1.5 to +1.5, and c) C) an amount of optically active component C such that the ratio of the layer thickness (the distance of the outer plates parallel to each plane) to the natural pitch of the chiral nematic liquid crystal mixture is from about 0.2 to 1.3; And d) a nematic phase range of at least 60 ° C., 35 mPa
Have a viscosity not higher than s and a threshold voltage lower than 1.75 V, wherein the dielectric anisotropy of the compounds and the various parameters based on their nematic liquid crystal mixture are 2
In the above display, for a temperature of 0 ° C., the component A is present in an amount of from 20 to 40% by weight of at least one

[0019]

Embedded image Wherein R ¹ is alkyl having 1 to 8 carbon atoms, m is 0 or 1, and
Represents H or F] and said component B is present in an amount of from 15 to 35% by weight of at least one of the following formulas II

[0020]

Embedded image Wherein n is 0 or 1, preferably 1, R ² is H, or alkyl having 1 to 8 carbon atoms, and R ³ is alkyl having 1 to 8 carbon atoms, Alkenyl or oxaalkyl].

Preferably, the compounds of formula I are of the following formulas I1, I2
And the compounds of I3:

[0022]

Embedded image Provided that in these formulas R ¹ is alkyl having 1 to 8 carbon atoms.

In another preferred compound of formula I, L represents F.

Preferably component A has the formula I1 and / or I2
And at least one compound of formula III:

[0025]

Embedded image Wherein R is alkyl, alkoxy, oxaalkyl, alkenyl or alkenyloxy having up to 12 carbon atoms,

[0026]

Embedded image Are independently

[0027]

Embedded image Preferably

[0028]

Embedded image L ³ to L ⁶ are each independently H or F;
¹ and Z ² are —COO—, —CH ₂ CH ₂ —, —C≡C—
Or a single bond, preferably a single bond or —CH ₂ CH ₂ —, Q is CF ₂ , OCF ₂ , CFH, OCFH or a single bond, preferably a single bond, OCF ₂ or CF ₂ , and Y is F or Cl , Preferably F, and o is 0 or 1.

Particularly preferred are those in formula III wherein Q is a single bond, --OCF ₂ or --CF ₂ ;
Is F and o is 1.

Compounds selected from the following formulas IIIa to IIIh are particularly preferred:

[0031]

Embedded image However, in these formulas, R, L ³ and Q have the meanings mentioned above.

Preferably, component B comprises one or more compounds selected from the group consisting of compounds of formulas IV and V:

[0033]

Embedded image However, in these formulas, R ⁵ and R ⁶ have the meanings given for R ¹ ,

[0034]

Embedded image And L ¹ have the meaning given for formula III, Z ³ is —COO—, —CH ₂ CH ₂ —, —CH ＝ CH— or a single bond, and Z ⁴ is —COO— or a single bond. And r is 1, 2 or 3.

In one particularly preferred embodiment, component B comprises at least one compound of formula I1 and a compound of formula V1

[0036]

Embedded image (Wherein R ⁵ and R ⁶ are each independently alkyl having 1 to 8 carbon atoms, L ⁰ is H or F,
k and l are each independently 0 or 1, and among them L ⁰
Is F, k is 1 and l is 0), and / or
At least one compound wherein L ⁰ is H, k is 0, and 1 is 0 or 1 in 1.

Preferably component B has the formula II1a

[0038]

Embedded image (Where m and p are each an integer between 0 and 8, and the sum of m + p is an integer between 1 and 8, wherein m is 0 or 1; And p is 2, 3, 4 or 5).

The invention also relates to the corresponding liquid-crystal mixtures.

The individual compounds of the above formulas I1, I2, I3, II and III, and also other compounds which can be used in the STN display according to the invention, are known or made analogously to known compounds. be able to.

Compounds of formula I1 are disclosed in US Pat.
817, the compounds of the formulas I2 and I3 are known from European patent EP 0,019,665, and the compounds of the formula II are from German patent DE 3509170.
And in part from WO 95/30723, the compounds of the formula III are described, for example, in German patent DE 3
732284, DE 3042391 and DE 3
No. 929,525 and the compounds of the formula VI are described in German Patent Publications DE 293,563 and DE 3211.
Although known from 306, there is no indication in these publications that these compounds can improve the STN abruptness or switching time.

These mixtures according to the invention have a high multiplex ratio, a wide operating temperature, a low threshold voltage (below 1.8 volts, preferably between 1.25 and 1.50 volts, in particular 1.30 volts). (Between 1.50 volts) and an STN display having a steep characteristic curve.

The compounds of the formulas I1, I2, II1 and II2 give the improved STN display, inter alia, a higher clearing point, while the compounds of the formulas II1 and II2 give the elastic modulus ratio (K
₃ / K ₁ ) and thus leads to high steepness.

The mixtures according to the invention have an optical anisotropy (Δn) higher than 0.110, preferably between 0.120 and 0.150.

[0045]

DETAILED DESCRIPTION OF THE INVENTION The mixture according to the invention is preferably a compound of the formula III having three rings selected from the group
Contains one or more compounds:

[0046]

Embedded image

[0047]

Embedded image Preferred mixtures have the formulas I1, I2, I3, II1, IIIc and I
It comprises two, three or more compounds of the formula IIh, in particular one or more compounds of the formula IIIc, two to four compounds of the formula I1 / I2 and one selected from the formulas II1 and II2.
One to five compounds.

Preferred liquid-crystal mixtures which can be used according to the invention comprise one or more compounds from group A, preferably in a proportion of from 20% to 90%, preferably from 35% to 80%. The compounds from group A have a dielectric anisotropy higher than +8 (preferably higher than +12) and constitute component A of the liquid-crystal mixtures according to the invention.

Preferred liquid-crystal mixtures contain two or more compounds from group B, preferably in a proportion of from 10% to 40%. The compounds from this group B have low rotational viscosities (γ ₁ ) of <150 mPa · s or clearing points higher than 120 ^° and are dielectrically neutral (| Δε | <2). It is of moderate or moderate polarity (Δε in the range of +2 to +10, preferably +4 to +8) and constitutes component B of the liquid crystal mixture according to the invention.

Preferably component B has the formula II1 and II2
In addition to the compound of formula I, preferably containing two rings
Including one or more compounds selected from the group consisting of V1 through IV8:

[0051]

Embedded image (Wherein R ⁵ and R ⁶ have the meanings given for R) and / or one or more compounds selected from the group consisting of the following formulas IV9 to IV25 having three rings:

[0052]

Embedded image

[0053]

Embedded image (Wherein R ⁵ and R ⁶ have the meanings given for R and are of the formulas IV9 to IV18 and
Each of the 1,4-phenylene groups in IV22 and IV23 may be, independently of each other, mono- or polysubstituted by fluorine) and / or the following formulas IV26 to IV3
One or more compounds selected from the group consisting of:

[0054]

Embedded image (Wherein R ⁵ and R ⁶ have the meanings given for R and each 1,4-phenylene group in formulas IV26 to IV31 is, independently of one another, mono- or polysubstituted by fluorine. May be included).

The liquid-crystal mixtures also contain an optically active component C, the ratio of the layer thickness (the distance between the plane-parallel carrier plates) to the natural pitch of the chiral nematic liquid-crystal mixture being suitable for the desired twist angle. It is included in such an amount that it becomes larger than 0.2.

Suitable dopants include a wide range of known chiral substances and, for example, cholesteryl nonanoate, S 8
11 (E. Merck, Darmstadt, Federal Republic of Germany)
And CB 15 (BDH, Poole, UK).
The choice of this is not critical.

In another preferred embodiment, the liquid crystal mixtures comprise one or more compounds selected from the group T consisting of the compounds of the formulas T1 and T2:

[0058]

Embedded image However, in these equations, Q ³ is

[0059]

Embedded image And

[0060]

Embedded image Is

[0061]

Embedded image Preferably

[0062]

Embedded image L ³ to L ⁶ , Q and Y are as defined for each compound of formula III, R ⁹ and R ¹⁰ are each independently R and Z ⁰ is —COO
—, —CH ₂ CH ₂ — or a single bond.

The proportion of each component in group T is preferably 5%
To 30%, especially 5% to 20%.

Preferably, group T comprises one or more compounds selected from the group consisting of the following formulas X to XII:

[0065]

Embedded image With the proviso that in these formulas R ⁹ and R ¹⁰ have the meanings given above, in which R ⁹ is in particular alkyl having 1 to 4, most preferably 1 or 2 carbon atoms, And R ¹⁰ is alkoxy having 1 to 4, most preferably 1 or 2 carbon atoms.

Particularly preferred compounds of the formula IV2 are of the subordinate formula

[0067]

Embedded image Wherein R ¹³ is CH _3- (CH ₂ ) _n -O- or trans-H-
_{(CH 2) r -CH = CH-} (CH 2 CH 2) S -CH
₂ O— and R ¹⁴ is CH ₃ — (CH ₂ ) _t —
Where n is 1, 2, 3 or 4 and r is 0, 1, 2
Or 3; s is 0 or 1;
Is 1, 2, 3 or 4.

The proportion of these compounds or of each compound of the formula IV2 is preferably about 2% to 15%, especially preferably about 4% to 10%.

At least one compound of the formula I1 and a compound of the formula I
Mixtures according to the invention comprising at least two compounds of 2 are particularly preferred.

The proportion of each compound of the formulas I1 and I2 is preferably about 25% to 35%, in particular 27% to 32%.
%.

In one particularly preferred embodiment, the mixture comprises from about 5% to 35%, preferably about 1%.
It contains 0% to 20% of a liquid crystalline tolan compound. These make it possible to work with smaller cell thicknesses (5-6 μm), which significantly reduces switching times. Particularly preferred tolan compounds are shown below:

[0072]

Embedded image However, in these formulas, R ⁹ is preferably n-alkyl having 1 to 7 carbon atoms, and Z ⁰ is preferably -CH ₂ CH
₂ -or a single bond,

[0073]

Embedded image Is

[0074]

Embedded image Preferably

[0075]

Embedded image And Q ³ is

[0076]

Embedded image Preferably

[0077]

Embedded image Wherein R ¹⁰ is preferably n-alkyl or n-alkoxy, each having 1 to 7 carbon atoms, or n-alkenyl or n-alkoxy, each having 3 to 7 carbon atoms. -Alkenyloxy.

Preferably component A comprises one or more compounds of the formula T1b:

[0079]

Embedded image However R ¹¹ In this formula _{-C n H 2n + 1, -OC} n H 2n + 1,

[0080]

Embedded image And n is an integer from 1 to 15, L ³ through L ⁶ is H or F independently of each other, and X is F, Cl or OCF _3.

In one preferred embodiment, the nematic mixture comprises 3-10% of one or more compounds of formula I1, 18-30% of two or more compounds selected from formula I2, 5-15% Of one or more compounds of Formula II1 and 10-20% of two or more compounds of Formula II2.

These mixtures have very short switching times of less than 450 ms, between 1.04 and 1.10
Steepness, birefringence value of 0.12 to 0.14 and 1.
Shows a threshold voltage between 2 and 1.6 volts.

In another particularly preferred embodiment, the mixture comprises:

[0084]

Embedded image (Where R is a linear alkyl group having 2 to 7 carbon atoms and X is H or F
O) one or more compounds wherein R is trans-alkenyl or trans-alkenyloxy; and o the following groups:

[0085]

Embedded image Wherein R ⁵ and R ⁶ have the preferred meanings given for component B, and one or two of the 1,4-phenylene groups may be substituted by fluorine. One or more compounds, wherein the proportion of these compounds is 0% to 25%, preferably about 5% to 15%.

In general, component B consists of 3 to 10, preferably 4 to 9, different compounds.

In one of the preferred embodiments, component B consists essentially of at least one compound of the formula II1 and / or II2 and at least one compound selected from the following formulas:

[0088]

Embedded image

[0089]

Embedded image Wherein Alkyl is an alkyl group having up to 12 carbon atoms. Component B preferably consists of 3 to 10 compounds,
4-20%, in particular 6-16%, of one, two or three of the compounds of the formula II1 and / or 10-40%, in particular 15-30%, of one of the compounds of the formula II2, One or three
3-20%, especially 5-15%, at least one of PCH-nOm or CCH-nOm 0-20%, especially 1-16%, at least one of PTP-nOm, 0-20%, Especially 1-16% of CPTP
At least one of nOm, 0-20%, especially 1-15
%, At least one of the BCH-nm, 0-15%, especially 5-10%, of at least one of the CCP-nm, 0-%.
40%, especially 5-30%, at least one of the CP-nmF and 0-20%, especially 6-15%, of the CBC-n
m, one, two or three compounds selected from CBC-nmF and CCP C-nm.

In general, component A consists of 2 to 9, preferably 4 to 7, compounds. Preferred Embodiment 1
In one embodiment, component A has essentially the formulas I1, I2, I3 and III
Consisting of at least one compound selected from among the following formulas:

[0091]

Embedded image Wherein Alkyl is an alkyl group having up to 12 carbon atoms. Component A is preferably 20-60%, especially 15-45%
Of at least one compound of formula CCP-nOCF _3, 40-80%, in particular of 45-75%, ME-nN,
At least one compound of the formulas ME-nNF and HP-nNF, 0-20%, in particular 2-10%, of CPTP-n
At least one compound of formula OCF ₃ and 5-30
%, Especially 10-25%, of at least one compound of the formula BCH-nFF.

Component B preferably comprises at least one compound of the formula II1 and at least one tolane derivative, in particular from 3 to 0.3 parts of the compound of the formula II1 per part of the tolane compound.

The structure of the liquid crystal display element according to the present invention is generally such that the polarizer, the electrode substrate and the surface-treated electrodes are all provided with preferential alignment (director) of the liquid crystal molecules adjacent to them. 16 from the other to the other
Twisted with each other by a value between 0 ^° and 720 ^° and included in a manner compatible with the conventional construction of this type of display element. 220 ^o and 270
Displays having a twist angle between ^o and ^o are preferred. The term "conventional" is used herein in a broad sense and includes all derivatives and modifications of supertwist cells, including, inter alia, matrix display elements. The surface tilt angles of the two support plates may be the same or different. The same tilt angle is preferred.

However, an essential difference between each display element according to the invention and the conventional conventional display elements based on twisted nematic cells is the choice of the liquid crystal components in the liquid crystal layer.

The liquid-crystal mixtures which can be used according to the invention are prepared in a customary manner. In general, the desired amount of each component used in relatively small amounts is dissolved in the main constituent components, conveniently at elevated temperature. It is also possible to mix the solutions in which the components are dissolved in an organic solvent such as, for example, acetone, chloroform or methanol, and to remove after this mixing again, for example by distillation.

The dielectrics can further contain other additives as known to those skilled in the art and described in the literature. For example, 0-15% of a polychromatic dye can be added.

From the above description, it is believed that one skilled in the art can practice the present invention without any additional effort and throughout its technical scope. Accordingly, it should be understood that some of the preferred specific embodiments described below are merely illustrative and that the disclosure is not intended to limit the embodiments.

[0098]

The following examples are intended to illustrate the invention without any limitations.

Each abbreviation used has the following meaning: c. p. : Transparent point T _ave : Average switching time = (T _on + T _off ) /
2 _Ton : 90% of maximum contrast from switch-on
_Toff : 10% of maximum contrast from switch-off
Reach time V ₁₀ to: a threshold voltage V _90: saturation voltage V ₉₀ / V _10: steepness SFA multiplex operation (multiplex ratio 1: 240, bias 1:15) is addressed in.

Above and below, all temperatures are given in ° C. Percentages are weight percentages. Switching times and viscosity values are at 20 ° C.

In this specification and the following examples, all chemical structures of liquid crystal compounds are indicated by abbreviations,
The conversion of this into a chemical formula is performed as shown below.
All C _n H _{2n + 1} and C _m H _{2m + 1} groups are each n
Or a linear alkyl group having m or m carbon atoms. The symbols in Table B are self-evident. Table A lists only the abbreviations for the core structure. In specific compounds, the abbreviations are followed by a hyphen to add the following R ¹ ,
The symbol of each substituent of R ² , L ¹ and L ² is mentioned.

[0102]

[Table 1]

[0103]

[Table 2]

[0104]

[Table 3]

[0105]

[Table 4] Example 1 An STN display having the following parameters: twist angle 240 ^° bias 1:16 multiplex ratio 1: 240 frame rate 80Hz tilt angle 5 ^° d 6.1 μm has the following properties: clearing point + 100 ^° Δn 0.1257 Contains a liquid crystal medium, which is a non-chiral base mixture of

[0106]

[Table 5] And 0.61% of the following:

[0107]

Embedded image And exhibits the following switching parameters T _ave 409 ms V ₁₀ 1.47 volts V ₉₀ / V ₁₀ 1.064. Example 2 An STN display containing a liquid crystal medium with the following parameters, described in Example 1, ie N-1 + 100 ° C. Δn 0.1320, is a non-chiral base mixture:

[0108]

[Table 6] And doped with 0.61% S-811, which exhibits the following switching parameters T _ave 355 ms V ₁₀ 1.48 volts V ₉₀ / V ₁₀ 1.067. Example 3 An STN display comprising a liquid crystal medium having the following parameters N-1 + 102 ° C. Δn 0.1240 described in Example 1 is a non-chiral base mixture:

[0109]

[Table 7] And doped with 0.61% S-811, which exhibits the following switching parameters T _ave 466 ms V ₁₀ 1.49 volts V ₉₀ / V ₁₀ 1.055. Example 4 An STN display containing a liquid crystal medium having the following parameters N-1 + 98 ° C. Δn 0.1244 described in Example 1 is a non-chiral base mixture:

[0110]

[Table 8] And doped with S-811, which exhibits the following switching parameters T _ave 438 ms V ₁₀ 1.45 volts V ₉₀ / V ₁₀ 1.062.

 ──────────────────────────────────────────────────続 き Continuation of front page (71) Applicant 591032596 Frankfurter Str. 250, D-64293 Darmstadt, Federal Republic of Germany (72) Inventor Hiroshi Numata 1351 Miho-cho, Midori-ku, Yokohama, Kanagawa Prefecture 3-302 Miho, Forest Hills

Claims (9)

[Claims] 1. Two plane-parallel outer plates forming a cell with a frame; a nematic liquid crystal mixture of positive dielectric anisotropy present in the cell; A pretilt angle between about 1 and 30 degrees between each outer plate and the longitudinal axis of each molecule at the surface of these outer plates; and 1 from the alignment layer to the alignment layer of the liquid crystal mixture
00 ^o and a supertwisted liquid crystal display comprising the twisted angle having a value between 600 ^o, that time the nematic liquid crystal mixture, a) from 20 to 90 wt%, greater dielectric anisotropy than + 1.5 B) 10 to 65% by weight of a liquid crystal component B comprising one or more compounds having a dielectric anisotropy from -1.5 to +1.5, and c) containing an amount of optically active component C such that the ratio of the layer thickness (the distance of the outer plates parallel to each plane) to the natural pitch of the chiral nematic liquid crystal mixture is from about 0.2 to 1.3. And d) a nematic phase range of at least 60 ° C., 35 mPa
Have a viscosity not higher than s and a threshold voltage lower than 1.75 V, wherein the dielectric anisotropy of the compounds and the various parameters based on their nematic liquid crystal mixture are 2
The above display, wherein the component A is at a temperature of 0 ° C.
One of the following formulas I Wherein R ¹ is alkyl having 1 to 8 carbon atoms, m is 0 or 1, and
Represents H or F] and the component B is present in an amount of from 15 to 35% by weight of at least one of the following formulas II: [However, in this formula, n is 0 or 1, R ² is H,
Or alkyl having 1 to 8 carbon atoms,
And R ³ is an alkyl, alkenyl or oxaalkyl having 1 to 8 carbon atoms]. 2. Component A comprises at least one of the following formulas I1
And / or I2 And at least one of the following formulas III: Wherein R 1 is alkyl, alkoxy, oxaalkyl, alkenyl or alkenyloxy having up to 12 carbon atoms, Are each independently L ³ to L ⁶ are each independently H or F;
Z ¹ and Z ² are —COO—, —CH ₂ CH ₂ —, —C}
C- or a single bond, and Q is CF ₂ , OCF ₂ , C
FH, OCFH or a single bond, and Y 1 is F or Cl
And o is 0 or 1.]. Wherein Q is a single bond, -OCF ₂ or -CF ₂
And o is 1 and Y is F.
A display according to claim 2. 4. Component A is represented by the following formula IIIa to IIIh: [However R, L ³ and Q in these formulas have the meanings mentioned in claim 2] comprises at least one compound selected from display according to claim 1. 5. The composition according to claim 1, wherein said component B has the following formula IV and V: Wherein R ⁵ and R ⁶ have the meanings given for R in claim 2, and And L ¹ have the meaning given for formula III and Z ³
Is _{-COO -, - CH 2 CH 2} -, - CH = CH- or a single bond, Z ⁴ is -COO- or a single bond,
And r 1 is 1, 2 or 3]. The display according to claim 1, comprising one or more compounds selected from the group consisting of: 6. Component B is represented by the following formula II1a: 2. The compound of claim 1, wherein m and p are each an integer between 0 and 8, and the sum of m + p is an integer between 1 and 8. A display according to any one of claims 1 to 4. 7. The nematic liquid crystal mixture further comprises the following formula X
Or XII The display according to any one of claims 1 to 6, comprising one or more compounds selected from the group consisting of: wherein R ⁹ and R ¹⁰ have the meanings given for R in claim 2. 8. The method according to claim 1, wherein the nematic mixture has a content of 3 to 10%.
One or more compounds of formula I1, 18 to 30% of two or more compounds selected from formula I2, 5 to 15% of one or more compounds of formula II wherein n is 0, and 10 to 20% A display according to any of claims 1 to 7, comprising two or more compounds of formula II wherein n is 1. 9. A liquid crystal mixture having a composition as defined in claim 1.