JPH02227489A - Ferroelectric liquid crystalline composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition giving liquid crystalline display element having excellent responsiveness and memory properties by adding specific compound as chiral dopant to liquid crystalline composition exhibiting optically inactive smectic C-phase. CONSTITUTION:(C) A compound expressed by formula I (R<a> and R<b> are 2-10C alkyl; Z<a> and Z<b> are -CO2- or -O-, etc.; X is expressed by formula II, etc.) is added as a chiral dopant to a mixture of (A) a middle-temperature range matrix liquid crystal comprising optically inactive and may be monotropic at >=10 deg.C (i) a liquid crystalline compound (homologue) exhibiting bicyclic smectic C-phase or (ii) a liquid crystalline compound (homologue) exhibiting tricyclic smectic C-phase having cyclohexyl ring and (B) a liquid crystalline composition comprising optically inactive and may be monotropic at >=90 deg.C (iii) a liquid crystalline compound exhibiting smectic C-phase of >= tricyclic ring structure and (iv) high-temperature liquid crystal as homologue of the component (ii) to afford the aimed composition.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a novel liquid crystal composition useful as an electro-optical display material, and in particular provides a liquid crystal material having ferroelectricity, which is different from conventional liquid crystal compositions. The object of the present invention is to provide a liquid crystal material that has particularly excellent responsiveness and memory performance compared to liquid crystal materials, and can be used for liquid crystal display elements.

[Prior art]

The currently widely used liquid crystal display elements are mainly of the TN type, which utilizes nematic liquid crystals, and although they have many advantages, their responsiveness is inferior to that of light-emitting types such as CRTs. Compared to the display method, it had the major drawback of being much slower. Many liquid crystal display systems other than the TN type have been studied, but improvements in their responsiveness have not yet been achieved.

However, in liquid crystal devices using ferroelectric smectic liquid crystals, the 100 to 10
It has recently been revealed that because it is capable of a 00 times faster response and has multistability, it can retain the display even when the power is turned off (memory effect). For this reason, it has great potential for use in optical shutters, printer heads, flat-screen televisions, etc. (Currently, research and development is being conducted in various fields toward practical application.

The liquid crystal phase of ferroelectric liquid crystals belongs to the tilted chiral smectic phase, and among these, the one that is practically desirable is chiral smectic C (hereinafter abbreviated as "SC"), which has the lowest viscosity. This is called a phase.

[Problem to be solved by the invention]

Liquid crystal compounds exhibiting the S00 phase (hereinafter referred to as SC2 compounds) have been studied, and many compounds have already been synthesized. However, these SC
One compound alone must meet the following conditions for use as an optical switching element for ferroelectric liquid crystal displays: (a) It must exhibit ferroelectricity in a wide temperature range including room temperature; (b) It must have an appropriate phase in a high temperature range. Having a series (c) Particularly chiral nematic (hereinafter abbreviated as No).

) exhibiting a long helical pitch in the phase; (d) having an appropriate tilt angle; (e) having low viscosity; (f) having a large spontaneous polarization above a certain level. There has been no known material that satisfies all of (1), (5), (e), and (f), which include good orientation as a result of (1), high-speed response as a result of (f), and (f).

Therefore, at present, liquid crystal compositions exhibiting an SC'' phase (hereinafter referred to as S00 liquid crystal compositions) are currently being used for study purposes.

In order to obtain good orientation, for example, JP-A-61-1
As shown in Japanese Patent No. 53623, etc., in liquid crystals having an N8 phase in the high temperature range of the SC0 phase, a method of increasing the helical pitch length of the N11 phase is generally effective.

In this case, if the smectic A (hereinafter abbreviated as SA) phase is present in the temperature range between the 5011 phase and the N0 phase, the orientation will be better, and in order to increase the helical pitch,
It is also known that an optically active substance that produces a left-handed helix and an optically active compound that produces a right-handed helix may be used in combination. (It is already a known technique to adjust the helical pitch to an arbitrary length by adding an optically active substance to a nematic (hereinafter abbreviated as N) liquid crystal.) However,
Although these techniques can provide good orientation, they do not provide high-speed response.

In order to exhibit high-speed responsiveness, for example, low viscosity smectic C (hereinafter abbreviated as SC) is used, as shown in the special lecture at the 12th Liquid Crystal Conference (Proceedings of the same conference P, 98). ) phase (hereinafter referred to as SC matrix liquid crystal) has a spontaneous polarization (hereinafter abbreviated as Ps).

) is better.

According to this method, the proportion of the optically active compound that produces the helix is small, so the helical pitch is relatively long. need to be,
Therefore, there was a problem in that the spontaneous polarization became too small, making it impossible to obtain high-speed response.

Furthermore, those that have been used hitherto as SC matrix liquid crystals are described in, for example, Japan Display 86 Lecture Proceedings (from page 352) or Japanese Patent Application Laid-open No. 1983-583.

(R, R' represent an achiral alkyl group.) (R,
R' is the same as above, and the compound itself or its homolog is limited to those exhibiting an SC phase, or in addition exhibits a strong dipole (polarization) in the direction perpendicular to the long axis of the molecule. The problem is that if the temperature range of the SC phase is kept wide, the viscosity becomes thick, and if the viscosity is decreased, the temperature range of the SC phase becomes narrow.

Therefore, with the prior art, it has been difficult to simultaneously achieve good orientation and high-speed response.

The problem to be solved by the present invention is to provide a ferroelectric liquid crystal composition that is fully satisfactory in both high-speed response and orientation.

[Means to solve the problem]

In order to solve the above problems, the present invention provides an SC base liquid crystal containing a medium temperature range base liquid crystal and a high temperature liquid crystal as shown below. represents an alkyl group having 2 to 10 carbon atoms, and! is 0-1
Represents an integer of 0, Zl is -0--coo--oco-
or represents a single bond, Z1' represents 1000- or -0-, C0 and C0 each independently represent (R) or (S)
Provided is an SC0 liquid crystal composition in which a chiral dopant containing an optically active compound represented by general formula (B), general formula (C), or general formula (D) is added, where X represents an asymmetric carbon atom in the configuration. .

It represents a 5-membered or 6-membered hydrocarbon ring, and any 1 to 2 -CIl= in the ring may be substituted with -N- or -C=, and Any 1 to 2 -CH
8- is -0--5--Nll--cL-c--5-1
or -〇-, m and n each independently represent O or 1
represents. ) represents the central skeleton (core) part of a liquid crystal molecule.

In particular, in general formula (A), X may be represented by general formula (E). Yl represents a fluorine atom, a chlorine atom, a cyano group, a methyl group, or a methoxy group, and ZIZ! Or each Z3 is independently a single bond, -C00OCOC1! O0CHHz
CHgCHg--5-C- or -CH=C)I-
, Z4 represents -C)I, --CHgCHg- CH=C)l CCHtC- and m is O or Represents 1. Y2 and ys each independently represent a fluorine atom, a chlorine atom, a cyano group, or a hydrogen atom, but Y2 and Y3 do not represent a hydrogen atom at the same time. ) are particularly preferred.

The SC matrix liquid crystal in the present invention is characterized by consisting of a medium-temperature matrix liquid crystal and a high-temperature liquid crystal. , a 2- or 3-ring structure, in the case of a 3-ring structure, at least one ring is a cyclohexyl ring, and the compounds exhibiting an SC phase or differ only in the number of carbon atoms and the shape of their alkyl chains. consisting of homologs, and at least one compound in the homologues is free from any
It is a compound that exhibits an SC phase, which may be monotropic, in a temperature range of ℃ or higher. However, in the case of a three-ring structure, S
It is a liquid crystal whose upper limit temperature of C phase is less than 90℃, and 10℃
It exhibits an SC phase that may be monotropic in any temperature range of 10°C or more at ~80°C.

Typical compounds used as medium-temperature host liquid crystals are listed below. However, in the general formula shown below,
R, and Rx each independently represent an alkyl group having 1 to 18 carbon atoms.

(1-a) (I -b) (1-c) (I -c-14) RIO+COO+'0COORt (I -c-15) R10+COO moxibustion COORx (I c-17) R, Coo ((anti-coo moxibustion COOR1 (1-c-19) (1-c-20) R,0CO4 prevention COO<H fermentation cooRzR10 (Kinco
osha COOR1 (I c-52) R1O child Coo-@-R.

(I-d) (I-e) (1-e-1) (1-e-2) (1-d-15) R-3-' (defense C00 (浬OR.

(1-d-21) R,0(■ COS then OR2 -N ρ (1-f) Among the above compounds, 2N-
a) and compounds represented by formula (I-b) are preferred,
Formula (1-a-1), Formula (1-a-2), Formula (I-a-5
), formula (I-a-41), formula (I-a-42) and formula (
Particularly preferred are compounds represented by 1-b-1).

The SC base liquid crystal used in the present invention contains high temperature liquid crystal in order to widen the temperature range of the SC phase even when a low viscosity medium temperature range base liquid crystal is used.

The high-temperature liquid crystal referred to here refers to an optically inactive compound that mainly consists of three or more rings and exhibits an SC phase, its homolog, or a composition consisting of these, and is composed of an SC phase. Compounds that exhibit SC phase have an upper limit temperature of 90°C or higher and exhibit SC phase in a temperature range of at least 5°C or higher, and their homologs have an upper limit temperature of less than 90"C. The temperature range may be less than 5 degrees, or the SC phase may be monotropic.
It exhibits an SC phase in a temperature range of at least 30°F.

Typical compounds used as high-temperature liquid crystals are listed below. However, in the general formula shown below, R,,
R, each independently represents an alkyl group having 1 to 18 carbon atoms.

(I!I-a) (■ b) (III-c) (■ d) C■-e (I[[-e (III-e-9) e-10) ・(Steel: I×)・・Feathers to match... R, O R -f) (III-g) (lI[-4) (II-j) ([[I-k) (■ Compounds having the following heterocycles can also be used as high a liquid crystals. Compounds having a heterocycle represented by the following general formula, in which a benzene ring or a cyclohexane ring is substituted with a fluorine atom, a chlorine atom, or a cyano group, can also be used as high-temperature liquid crystals.

(■---12) ([1l-s-13) (■-Kou-14) (II-a+-15) (■-Rin-16) R, COOΦh)COO(ji2 R, Φ figure COO-@-Rz R, or figure%coo()OR.

RIO and diagram λC00<　Rt R10 (Figure % coo4) OR.

(III-m-73) (In-m-74) (III-a+-75) (III-m-76) (m-5-77) ([[[-m-78) (m-m-79) (■-Inquiry-80) R1@-@-Coo and I R(1 coo thread R3 R10<H double 5 coo and I R,0 or +coo(3)')-oat R1℃X)COO■)OCORg R, COOΦ＋coo罎YR2 ? ,ya+cooip)h RIICOOR10R2 (n[-n) (III-n-29) (III-n-30) (DI-n-31) (m-n-32) (III-n-33) (I[l-n-34) (III-n-35) (III-n-36) R1 bag R, Coo illustration 0CO-@-R* R1 reactor X prevention 0CO-@;r-R2 RI (X defense 0CO-@-0Rx R10℃ section OCO<　Rt R,0-C lip protection 0CO()ORz R-”C pa defense 0CO()OCORz R, coo? Zubo OCO()R1 (I[[-n-61) (III-n-62) (nl　-n-63) (II[-n-64) (III-n-65) (In-n-66) Rt scale moxibustion 0CO-@-R2 R1 Sobe■oco-@-0R2 R+0 ancestor ■oco ((feather R2 R, 0 origin (9) OCO () OR1 R, progenitor (9) oco ()OCORz RICOO ancestor ◇0CO-@-Rz (I[[-n-93) (III-n-94) ([-n-95) (11-n~96) (m-n-97) (III-n-98) (III-n-99) ([1-n-100) R,o%oco-@-p.

R10nOC'-@-0R- 1 time+oco-@-0CORz R,coo% oco-('5)-pgR1@@-0
CO7＠rR- R1＠＠ｲ0CO-＠）-〇R2 R10＠ﾊ＠OCO+RｰR10% OCO-＠-0R2 (m -o) (m -o-17) (III-o-18) ([- o-19) Cm-o-20) (DI-o-21) (III-o-22) (I[I-o-23) ([[-o-24) R1 and Figure 5'yCI1. o()ocOR2! ? Ic[)
0℃+CH-0-@="zR8eC"-08R2 R to Tshiyama 030'? 2 R10(Me◇-cu2o((feather R2 R10(feather 1) mountain 0beomi>OR.

R1O$CH20()OCOR2 R, COO greeting 4CIlzO combination R2 (m-o-49) (III-o-50) (I [I　-o-51) (III-o-52) (III-o-53) (m-o-54) (m-o-55) (In　-o-56) R, -Ebe■co,o(shih R1(R or C11tO()OR* R, O-E hell moxibustion C11□0 (treatment.

RIO-"Cba moxibustion CH!0()ORt R1(be■CHtO+0CORt R,C00< C11tO()Rz mourning barφ (shiRt Cf1zORg mourningXΦ () Rt CIl*0 0Rt
(In -o-81) (I[I -o-82) (III-o-83) (II-o-84) (III-o-85) (III-o-86) (II[-o- 87) (III-o-88) R,0eCH,0(eR- R,0℃+co,o(,Q)-0R2R,-'C double-robust C1120i GocoR.

RICO jurisdiction p) (■ q) (II[-p-101) cap p-102) R1%OCH!30CORf R,C00n OCH礪in- (n[-q-25) (Lq-26) (m -q-27 ) (m -q-28) (m-q-29) (I[[-q-30) (III -q-31) (III-q-32) R1m CH2Cl-DR- R1 or $CHzCHz80Rt RIOi C) fIC11 attack) Rt R, O and 1CflzCfl□-@-0"-R, bag $CI
I□C11! -@-0COR2R, COO and hunting) C#1
□C1l□Join R2RI Yaodori) CH2c11□ (R+ <) CHtC11 attack) OR2 (I[[-q-61) (I[[-q-62) ([-q-63) ([[-q- 64) R, ZuHheiCH, CI! , 8R2 Crop + C1hC11280Rz R, O in 4shi C11 □ Mountain 8R- R109C112C112-@-OR2 (III -q
-89) (III -q-90) (m -q-91) (lI[-q-92) (nl -q-93) (m -q-94) (I[[-q-95) (n [-q-96) R1m C1,Cqki0CORz R,Coo℃+cuzcntD Rz R1$ C"ZCHbe5>R- R1% C)12CHbe5>01?.

RrO% CIICHbe5>R- R- R,0% co, cutG 0Rz Rbe◇-@=CII伪Sha0COR2 R,COOΦ4C1lIC1 Among the compounds with 5>Rt or higher, as a high temperature liquid crystal, the formula (I[-a ), formula (1-b
) and compounds represented by the formula (n[-c) are preferred,
Formula (I[I-a-1), Formula (II-a-2), Formula (II
-a-13), formula (Ill-b-1), formula (II-c-
Particularly preferred are compounds represented by 1) and formula (III-c-3).

In the SC base liquid crystal of the present invention, if the proportion of the high-temperature liquid crystal is too large, the temperature range of the SC phase will expand to a high temperature range, but the viscosity will increase and have a negative effect on the response. Since the range becomes narrow, the proportion is preferably 5 to 80% by weight, and 10 to 80% by weight.
Particularly preferred is 50% by weight.

In this way, the SC phase has a wide temperature range and low viscosity.
C matrix liquid crystal can be obtained. By adding a chiral dopant to this, it is possible to easily achieve high-speed response
A liquid crystal composition can be obtained.

The chiral dopant used in the present invention is composed of an optically active compound, and its constituent components include the above-mentioned general formula (A). compound or (3) a compound that does not exhibit liquid crystallinity at all, but in the case of (3), S
In order to prevent the tendency for the liquid crystallinity of the SC1 liquid crystal composition obtained by adding it to the C matrix liquid crystal to decrease, it is preferable to use a compound having a skeleton similar to that of a liquid crystal.

Among the various physical properties that the chiral dopant brings to the S01 liquid crystal composition, the important ones are the helical pitch it induces, the direction of spontaneous decentralization, and its size, which are determined by the optically active site of each compound constituting the chiral dopant. most affected.

Typical optically active groups in optically active compounds that have been used as chiral dopants, sc'' compounds, or additives to nematic liquid crystals are listed below.

It is characterized by containing at least one chiral compound represented by:

The chiral dopant used in the present invention includes (IV-
21) C113 1 umbrella -5+CH! +-CI(CHzY"CI(3(IV-
32) CH3 -0-CI-R4 (IV-'jtl) = Shiichiυ-L; H-L; It-υhs LIV-4 Sono-L; 1i-L; -υ-L; Fil-LJl.

(■ C.F.

1・ -0-CI-R.

(IV-64) C11□ CH3 C) I-CIl□-OR.

(IV-65) C1l.

1・ -0-CH-CH, -OR.

(IV-66) CHg -0-(-CHrsrCH(C1l,)-OR.

(IV -b'() - to U(lcth CI Lll G11
ls (IV-57) 0 C1h CHRs (IV -1)lJ -shi1υ-L;H-hs (IV-69) CI C0OCH2CHR5 (TV-70) -0-CI+□ CH3, CJl-CJl2-OCOR.

(■-71) C1l.

i-OCORs(IV-7
3) CH.

-0-CI! -CH-(CHhi,OCOR5(IV-
81) CN OCHz CHRs CN (■ COO H2CN CH2CI(R5 (IV-84) 10C)lICN CH2-CH-R.

In each of the above general formulas, m represents an integer of 1 to 4, and n
represents an integer of 1 to 10, R1 represents an alkyl group having 3 to 8 carbon atoms, R1 represents an alkyl group having 2 to 10 carbon atoms, and P represents an alkyl group having 1 to 10 carbon atoms. where R4 represents an alkyl group having 1 to 4 carbon atoms.

Optically active compounds containing only the optically active groups represented by formulas (IV-1) to (IV-22) as optically active groups are induced when added to the SC matrix liquid crystal to form an SC'' liquid crystal composition. The spontaneous polarization is very small, and even when the S01 phase is exhibited alone, most of it is only 10 nC/c or less.

On the other hand, as optically active groups, formulas (IV-31) to (■-9
The optically active compound containing the optically active group represented by 5) has a large spontaneous polarization induced when it is added to an SC matrix liquid crystal to form an SC liquid crystal composition, and when it exhibits an SC phase alone, it has a polarization of 300 There are some that exhibit large values of nC/cm" or more.

In the present invention, the odor group of the above-mentioned general formula (A) is of the formula (
IV-31) or its induced spontaneous polarization represented by formula (IV-32) is very small, so they do not particularly need to be the same.

The optically active group represented by the formula (IV-1) and the formula (■-
2), formula (IV-5), 2 (IV-6), formula (IV-7
), formula (IV-8), formula (IV-9), formula (IV-1
0), Formula (IV-12), Formula (IV-15), Formula (
IV-16), formula (rV-19), formula (IV-20
), formula (IV-31) or formula (rV-32).

CIl.

The optically active group represented by the general 2R"-CIl-SCIl, frl"- is represented by the formula (IV-31) or the formula (IV-32)
In the case of H3 selected from the formula (IV-31) or Formula (IV-
When compared with the optically active group represented by However, for the purpose of adjusting the helical pitch, it is also convenient to have a very short helical pitch, and in such a case, it is preferable that the directions of the helical pitches are the same.

The basic skeleton of an optically active compound having such an optically active group at its terminal (corresponds to X in general formula (A)).

) are listed below.

/ (V-24) -〈φ)←Cmic -@oco-0 (V shoto ■tan (V-72) ■) (', o)-oc・・-@ (V-120) min ...Nato〈: Now (■ ◇) oco -0begin (V-168) Sumioki...Saσ (V-192) 6 figure) OCO so (V-267) 0be) COO-@ ( V-480) Yaji CO^^ (V-481) Go CHffiO^6 (V-482) ■OCH! Akira (V-483) -Jc8) -000 Matsuiri (V-484) Sha oco Itoto (V-485) Sha CHg0 Hayashi (V-486) Sha ocn, Akira (V (Ba 發 coo 8 people (V 挺Baki oco Matsuiri (V (8ヰC) I, O^ included (V Yaba DOCtl! Eight people N Fluorine atom, chlorine atom,
Although basic skeletons substituted with a bromine atom, methyl group, methoxy group, cyano group or nitro group can also be used, basic skeletons substituted with a fluorine atom are often preferred.

Moreover, among the above-mentioned basic skeletons, those with left-right asymmetrical ones can also be used in the same way.

Among the above, the basic skeletons represented by formulas (V-1) to (V-274) and those in which the benzene ring thereof is substituted with fluorine are preferred, and formulas (V-1 to (V-3)), Formula (V-7) to Formula (V-9), Formula (V-17), (V-1
8), formula (V-21) formula (V-22) or formula (V-25
The basic skeletons represented by formulas 3 to (V-274) are particularly preferred.

Specifically, for example, the following compounds can be mentioned.

G (j () (In the above, C is a crystalline phase, N1 is a chiral nematic phase, SA
is smectic A phase, SCI is chiral smectic C phase, SB is smectic B phase, SE is smectic E phase,
SX represents a smectic phase of unknown origin; those whose transition temperature is not stated cannot be measured because they are crystallized, and those whose melting points are not stated cannot be measured because they do not crystallize.

The advantages of using the compound represented by the general formula (A) as a component of a chiral dopant are as follows:
Listed below.

(1) It can exhibit stronger spontaneous polarization than a compound having a chiral group on only one side.

That is, the above compound and the following general formula (E) (wherein R''
, Z', When each compound is added to the SC matrix liquid crystal and the spontaneous polarization is determined as an extrapolated value, under the same conditions, the compound of general formula (A) is more likely to have general formula CH.

10 to 30 nC/cm" when the optically active group represented by R"-CH+GHz→7 Z "- is selected from the optically active groups represented by formula (■-1) to formula (IV-22)"
or more, and is larger than the simple sum of the spontaneous polarizations due to the chiral groups on both sides, formula (IV-31), formula (IV
-32), formula (TL-33), etc., even larger spontaneous polarization can be obtained by matching the direction of the spontaneous polarization.

When used as a chiral dopant, the larger the spontaneous polarization it induces, the smaller the amount required, so the proportion of the SC host liquid crystal with low viscosity can be increased, making it possible to reduce the viscosity of the SC* liquid crystal composition. As a result, this leads to improved responsiveness.

(2) It is possible to adjust the helical pitch, such as compounds with very long helical pitches and compounds with very short helical pitches induced in the N'' phase or S08 phase.

As mentioned above, in order to obtain good orientation, it is important that the helical pitch in the N" phase or SC1 phase is long. The pitch of the chiral dopant as a whole needs to be adjusted, and Although this is not necessarily the case for individual compounds, it is easier to adjust the helical pitch as the main component of the chiral dopant if the helical pitch is long to some extent. The shorter the helical pitch is, the more advantageous it is because the amount added can be suppressed.

It is effective to use the compound of general formula (A) in an amount of 10% by weight or more, preferably 30% by weight or more, and particularly preferably 50% by weight or more as a constituent component of the chiral dopant.

Other constituents of the chiral dopant include the above formula (
V-1) to the basic skeleton represented by formula (V-539)
A compound in which any two or one of the optically active groups represented by formulas (IV-1) to (IV-95) are bonded as a side chain can be used.

(However, the compound of general formula (A) is excluded.) It is appropriate that the above chiral dopant is added to the SC base liquid crystal at a ratio of 1 to 60% by weight and used as the S01 liquid crystal composition. Preferably, it is added at a ratio of 2 to 50%. The addition ratio of chiral dopant is 6
If it is more than 0%, the spontaneous polarization will increase, but the chiral F
- Since the viscosity of the punt itself is much higher than that of the base liquid crystal, the viscosity of the S08 liquid crystal composition increases, which tends to adversely affect high-speed response, which is undesirable. Further, an increase in the amount of chiral dopant added tends to shorten the helical pitch, which tends to adversely affect the orientation, which is not preferable. On the other hand, if the proportion of the chiral dopant added is less than 1% by weight, the spontaneous polarization becomes too small and high-speed response cannot be expected.

SC" The spontaneous polarization value of the liquid crystal composition is 3 to 30 nC/c
It is preferable to adjust the addition ratio of the chiral dopant so that it is within the range of 100 nC/Cl1ffi, and in the case of a chiral dopant that exhibits the SC phase, it alone exhibits spontaneous polarization of about 100 nC/Cl1ffi, or has an intensity equivalent to that. In the case of a chiral dopant that induces spontaneous polarization, the addition ratio of the chiral dopant is preferably in the range of 10 to 40% by weight, and 300% by weight.
In the case of a chiral dopant that exhibits strong spontaneous polarization of nC/cta" or more, the addition ratio of the chiral dopant is 2 to 2
The most desirable addition ratio is preferably in the range of 5% by weight. The stronger the spontaneous polarization induced by the chiral dopant, the lower the most desirable addition ratio. do not have.

When the S00 liquid crystal composition of the present invention is cooled from an isotropic liquid state, it first undergoes a phase transition to the N0 phase, and then passes through the SA phase or directly to the S06 phase; The temperature range showing the phase is preferably in the range of 3° or more and less than 30". If the temperature range showing the N* phase is less than 3°, the phase transition to the SA phase occurs promptly when the temperature is lowered.
This is not preferred because it tends to make it difficult to fully align liquid crystal molecules in the N* phase. In addition, the temperature range showing the N1 phase is 30
If the temperature exceeds 1, the clearing point of the S08 liquid crystal composition becomes high, which tends to adversely affect workability in the step of filling a cell with liquid crystal material, etc., which is not preferable.

A chiraloo dopant is one that tends to expand the temperature range in which it exhibits (1) N'' phase when added to the SC matrix liquid crystal, regardless of whether the chiraloo dopant itself has liquid crystallinity or not (2) N ``Each has unique properties, such as those that tend to narrow the temperature range in which they exhibit a phase. S0 of the present invention
In order to adjust the temperature range in which the liquid crystal composition exhibits the N phase to the above-mentioned preferred range, in the case of (1), an SC base liquid crystal having a narrow temperature range in which the N phase is exhibited, or an SC liquid crystal that does not exhibit the N phase.
A base liquid crystal may be used, and in the case of (2), an SC base liquid crystal that exhibits an N phase over a wide temperature range may be used. This method can be applied not only to the N0 phase but also to the SA phase and SC* phase. For example, a chiral dopant expands only the SA phase of the SC'' liquid crystal composition, and the N1 phase and S
In the case where the C'' phase is to be reduced, the SC host liquid crystal should have a high upper limit temperature for the SC phase, a wide temperature range for the N phase, and a phase sequence of SC phase → N phase → 1 phase, or S
It is sufficient to use a material having a narrow temperature range of A phase and a phase sequence of SC phase→SA phase→N phase→I phase.

This tendency of chiral dopants is due to the fact that SC′″, which is obtained by adding a certain amount of chiral dopant to SC matrix
By measuring the change in phase transition temperature of the liquid crystal composition,
It is easy to know. From this result, the temperature range in which each phase in the S01 liquid crystal composition exhibits, particularly the N'' phase, can be easily adjusted.

Further, it is preferable that the helical pitch appearing in the N0 phase from the temperature at which the N" phase transitions to the SA phase or the S00 phase (lower limit temperature of the N" phase) to the 1° higher temperature side is 3 μm or more, and An sc" liquid crystal composition in which the helical pitch is 10 am or more and the helical pitch increases divergently as the lower limit temperature of the N1 phase is approached is particularly preferred in terms of alignment.

When an optically active compound represented by general formula (A) is used as a component of the chiral dopant in the present invention,
Although it is possible to obtain an SC4 liquid crystal composition with a long helical pitch that satisfies the above conditions even with a single compound, it is possible to obtain an SC4 liquid crystal composition with a long helical pitch satisfying the above conditions. does not necessarily satisfy the above conditions.

In that case, in order to adjust the helical pitch to the above-mentioned preferred range, when added to the SC base liquid crystal to form an SC" liquid crystal composition, the directions of the helices appearing in the N" phase may have opposite optical activity. It is necessary to prepare the chiral dopant by adding at least one compound at a time.

The pitch P (μm) of the helix that appears in the N1 phase of the S00 liquid crystal composition containing multiple optically active compounds is determined by the concentration of each optically active substance being Ct, and the pitch of the helix per unit concentration being Pi.
(μm), then P Pi is (Here, the right-handed spiral pitch is positive and the left-handed spiral pitch is negative.) Using this, 5A-
When Pi at point T0 is set as P, Ci can be selected such that Pi can be measured by adding each optically active compound at a unit concentration to the SC base liquid crystal having an N phase. It is.

In reality, To varies depending on each (j), but it can often be estimated fairly accurately from the change in the 5A-N'' point when each optically active compound is added to the SC matrix liquid crystal at a concentration ΣCi, etc. If the estimated value T 01 and To of the composition selected using it are significantly different, the measurement may be performed again using To instead of T.'.

The chiral dopant used in the present invention is required to induce a certain level of spontaneous polarization (hereinafter abbreviated as P) by adding it to a certain amount of SA host liquid crystal.

As mentioned above, for the S09 liquid crystal composition, the amount of the chiral dopant to be added may be adjusted so that the value of P is in the range of 3 to 30 nC/cm, especially near room temperature.However, if the chiral dopant is If the value of induced P is small, the amount added will be large relative to the SC base liquid crystal, and the viscosity of the S01 liquid crystal composition will increase accordingly, making it impossible to obtain high-speed response. Therefore, the chiral dopant used in the present invention is preferably one that can induce P6 of 1.OnC/cm! or more when added to the SC base liquid crystal in an amount of 10% by weight. 0,5 nC7 if
Particularly preferred are those that can induce P5 of cm'' or more.

[Examples] The present invention will be specifically explained below with reference to Examples, but the gist and scope of the present invention are not limited by these Examples. In addition, in the examples, "%" represents "weight %". The phase transition temperature of the composition can also be measured using a polarizing microscope equipped with a temperature control stage and a differential scanning calorimeter (
DSC) was used in combination.

Example 1 (Preparation of chiral dopant) The above formula (Vl-
25) Compound 20%, Compound 4 of the above formula (■-30)
A chiral dopant (hereinafter referred to as chiral dopant (A)) consisting of 38% of the compound (2% and 35 parts by weight) was prepared.

In addition, the blending ratio of the above three types of compounds was 20% and 4%, respectively.
Chiral dopants with concentrations of 8% and 32% (hereinafter referred to as chiral dopant (B)) were prepared.

When both chiral dopants (A) and (B) were added at 20% to an SC parent liquid crystal having an N phase, the helical pitch induced in the N1 phase was as long as 10 μm or more in the range of 50 to 60°C.

Example 2 As a medium temperature range host liquid crystal, among the compounds represented by the general formula (1-a-1), 15 parts by weight of the compound represented by the general formula (1-b-1), and As a high-temperature liquid crystal, an SC base liquid crystal consisting of a compound represented by the general formula (III-a-L) was prepared.

Next, an SC'' liquid crystal composition consisting of 65% of this SC matrix liquid crystal and 35% of the chiral dopant (B) obtained in Example 1 was prepared.

This SC* liquid crystal composition exhibits a 6"sc" phase at temperatures below 55°C.
The SC'' liquid crystal composition exhibits an SA phase at 8.5°C or lower, an N* phase at 75°C or lower, and an isotropic liquid (1) phase at higher temperatures.Next, this SC'' liquid crystal composition is subjected to alignment treatment. It was filled into a glass cell with a thickness of about 2 μm and subjected to (polyimide coating-rubbing), and when slowly cooled from the (2) phase, it showed extremely good orientation.

When a 50H2 rectangular wave with an electric field strength of 10 VP-P/μm was applied to this cell and its electro-optical response speed was measured, it showed a high-speed response of 91 r seconds at 30°C. The spontaneous polarization at this time was 10.5 nC/ctn''. Also, the tilt angle was 23.2° and the contrast was good.

Example 3 In Example 2, the general formula (III-
In place of the compound represented by a-1), -general formula (II-
Among the compounds represented by a-10), an SC" liquid crystal composition was prepared in the same manner as in Example 1 except that metal objects were used,
The electro-optic response speed was measured.

Electro-optical response speed: 109 μsec (35°C) Example 4 In Example 2, as the high temperature liquid crystal, the general formula (12r-
In place of the compound represented by a-1), the compound represented by the general formula ([[I-
An S04 liquid crystal composition was prepared in the same manner as in Example 1 except that one of the compounds represented by f-35) was used, and its electro-optical response speed was measured.

Electro-optical response speed: 110 μsec (30°C) Example 5 In Example 2, as the high temperature liquid crystal, general formula (II-a
-1) Instead of the compound represented by the general formula (1-f-
Example 6 Among the compounds represented by 42), the S01 liquid crystal composition was prepared in the same manner as in Example 1 except that one of the compounds represented by the general formula (1-a-1) was used as the medium-temperature range liquid crystal composition. We prepared a sample and measured its electro-optical response speed.

Electro-optical response speed: 105 μs (30°C) Reference Example In Example 2, a high-temperature liquid crystal was not used, and 65% of the SC base liquid crystal consisting of only a medium-temperature range base liquid crystal and a chiral dopant (
B) A S00 liquid crystal composition consisting of 35% was prepared.

In this S00 liquid crystal composition, the upper limit temperature of the S06 phase is 47.
5°C (melting point -4.5°C), and each S0 of Examples 2 to 5
0 liquid crystal composition.

and 15 parts by weight and 15 parts by weight of the compound represented by the general formula (1-b-1), and 35 parts by weight of the compound represented by the general formula (1-b-7), and the above as a high temperature liquid crystal. An SC matrix liquid crystal containing 42 parts by weight of the compound represented by the general formula (III-a, b-1) was prepared.

Next, an S01 liquid crystal composition consisting of 65% of this SC matrix liquid crystal and 35% of the chiral dopant (A) obtained in Example 1 was prepared.

In the same manner as in Example 2, the phase transition temperature and electro-optical response speed were measured.

After using 40 parts by weight and a compound represented by the general formula Clll-n-1) as a high-temperature liquid crystal, the electro-optic response speed was 135 μsec (26'C).The tilt angle at 26°C was 23.2' and the contrast was good. .

Example 7 An SC matrix liquid crystal consisting of 60 parts by weight of the compound represented by the general formula (1-al) was prepared as a medium temperature range matrix liquid crystal, and this SC matrix liquid crystal 70
% and chiral dopant (A) 30%.

The phase transition temperature and electro-optical response speed were measured in the same manner as in Example 2.

Electro-optical response speed: 8150 μsec (25° C.) [Effects of the invention] The ferroelectric liquid crystal composition of the present invention has excellent orientation and high-speed response, and can operate in a wide temperature range including room temperature. It is a liquid crystal material.

Therefore, the ferroelectric liquid crystal composition of the present invention is extremely useful as a material for liquid crystal devices using ferroelectric smectic liquid crystals.

teenager Reason Man

Claims (1)

[Claims] 1. (1) Smectic C having a two-ring structure, which is optically inactive and may be monotropic in any temperature range of 1 degree or more at 10 degrees Celsius or higher. (b) a liquid crystal compound exhibiting a smectic C phase with a three-ring structure having a cyclohexyl ring, or (c) the above (a)
or a homologue of the compound of (b) that differs only in the number of carbon atoms in the alkyl chain or in the structure;
2) Optically inactive, the upper limit temperature of the smectic C phase is 90°C or higher, and may be monotropic at least in a temperature range of 5°C or higher; (a) consisting of a 3-ring or more ring structure; , a liquid crystal compound exhibiting a smectic C phase, or (b) a high temperature liquid crystal exhibiting a smectic C phase consisting of a homologue of the compound that differs only in the number of carbon atoms or structure of the alkyl chain. (3) In the ferroelectric liquid crystal composition formed by adding a chiral dopant, the chiral dopant has the general formula (A) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [In the formula, R^a and R^b are each independently has 2 carbon atoms
~10 alkyl group, Z^a is -O-, -CO
Represents O-, -OCO- or a single bond, Z^b is -CO
Represents O- or -O-. C^* and C^*^* each independently represent an asymmetric carbon atom of (R) or (S) configuration. X is a general formula (B) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ General formula (C) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ Or general formula (D) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (Formula Medium, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas,
There are chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ and ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ are each independently saturated or unsaturated 5-membered or 6-membered ring hydrocarbons Although it represents a ring, any 1 or 2 -CH= in the ring may be substituted with -N= or ▲There are numerical formulas, chemical formulas, tables, etc.▼, and any 1 or 2 -CH= in the ring ~2 -CH_2- are
-O-, -S-, -NH-, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ may be substituted, and any one to The two ▲There are mathematical formulas, chemical formulas, tables, etc.▼ may be replaced with ▲There are mathematical formulas, chemical formulas, tables, etc.▼. Y^1 represents a fluorine atom, a chlorine atom, a cyano group, a methyl group, or a methoxy group, and Z^1, Z^2 or Z^3 each independently represent a single bond,
-COO-, -OCO-, -CH_2O-, -OCH_
2-, -CH_2CH_2-, -C≡C-, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas There are tables, etc. ▼ or -CH=CH-
represents, Z^4 is -CH_2-, -CH_2CH_2
-, -CH=CH-, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, -S-, or -O- Representation,
m and n each independently represent 0 or 1. ) represents the central skeleton (core) part of a liquid crystal molecule. ] A ferroelectric liquid crystal composition exhibiting a chiral smectic C phase over a wide temperature range including room temperature. 2.X is a general formula (E) ▲There are mathematical formulas, chemical formulas, tables, etc.▼
There are chemical formulas, tables, etc. ▼ and ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ are each independently ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲
There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼
, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼.
1 and Z^2 each independently represent the same as Z^1 or Z^2 in claim 1, and m represents 0 or 1. Y
^2 and Y^3 each independently represent a fluorine atom, a chlorine atom,
It represents a cyano group or a hydrogen atom, but Y^2 and Y^3 do not represent a hydrogen atom at the same time. ) The ferroelectric liquid crystal composition according to claim 1, which is represented by: 3. When cooling from an isotropic liquid state, 3 degrees or more 3
In the temperature range from the temperature at which the chiral nematic phase undergoes a phase transition from the chiral nematic phase to a phase on the lower temperature side through a chiral nematic phase having a temperature range of less than 0 degrees to the temperature 1 degree higher than the phase transition temperature, the chiral nematic 3. The ferroelectric liquid crystal composition according to claim 1, wherein the phase has a helical pitch of 3 μm or more. 4. The ferroelectric liquid crystal composition according to claim 3, which undergoes a phase transition to a chiral smectic C phase via a smectic A phase having a temperature range of 1 degree or more and less than 30 degrees upon cooling from a chiral nematic phase.