JPH02227490A - 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> is 2-10C alkyl; R<b> is 1-10C alkyl; Z<a> is -O- or -CO2-) 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 exhibiting smectic C-phase 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 100-10
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 to be used in optical shutters, printer heads, flat-screen televisions, etc., and research and development is currently being conducted in various fields to put it into practical use.

The liquid crystal phase of the ferroelectric liquid crystal belongs to the tilted chiral smectic phase, and among these, the one that is practically desirable is the chiral smectic C (hereinafter abbreviated as S01) phase, which has the lowest viscosity. It is called.

[Problem to be solved by the invention]

Liquid crystal compounds exhibiting the SC1 phase (hereinafter referred to as S01 compounds) have been studied, and many compounds have already been synthesized. However, these S0
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 N'').

) 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. No material has been known that satisfies all of (1), (5), (e), and (f), which include good orientation as a result of (1), and high-speed response as a result of (f).

Therefore, the current situation is that a liquid crystal composition exhibiting an "sc" phase (hereinafter referred to as "S01 liquid crystal composition") is used for study purposes.

In order to obtain good orientation, for example, JP-A-61-1
As shown in Japanese Patent Application No. 53623, etc., in a liquid crystal having an N8 phase in the high temperature range of the SC4 phase, a method of increasing the helical pitch length of the N1 phase is generally effective. In this case, if the smectic A (hereinafter abbreviated as SA) phase is present in the intermediate temperature range between the SC1 phase and the N1 phase, the orientation will be better, and in order to increase the helical pitch, optical It is also known that an active substance may be used in combination with an optically active compound that produces right-handed helix. (It is already a known technique to adjust the helical pitch to an arbitrary length by adding an optically active substance to a nematic (abbreviated as N) liquid crystal.) However, some of these techniques do not provide good results. Although orientation was obtained, high-speed response was not obtained.

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 superior.

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. ), the compound itself or its homologues are limited to those exhibiting an SC phase, or compositions in which a liquid crystal compound is added that exhibits a strong dipole (polarization) in the direction perpendicular to the long axis of the molecule. However, if the temperature range of the SC phase is kept wide, the viscosity increases, 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 adds at least one optically active compound represented by the general formula (A) to an SC base liquid crystal consisting of a medium temperature range base liquid crystal and a high temperature liquid crystal as shown below. Provided is an S00 liquid crystal composition that exhibits an S00 phase in a wide temperature range including room temperature, which is obtained by adding a chiral dopant as a constituent component.

In the general formula (A), R" represents an alkyl group having 2 to 10 carbon atoms, Rb represents an alkyl group having 1 to 10 carbon atoms, and 2 represents an integer of 0 to 10. Zl is -
o--coo--oco- or a single bond, but Z'
When ``represents 10- or -COO-, 2 is 1 to 10
represents an integer. C" and Cme are each independently (R)
represents an asymmetric carbon atom in the configuration or (S) configuration. X represents general formula (B), general formula (C), or general formula (D) -5-C- or -CH=C11-, and Z4 is -
Any 1 or 2 -CH= of CH2- is -N= or -
C= may be substituted, and any 1 to 1 in the ring
Two -C11□- are -0--3--Nl+--cI
t, -c--5-1 or -0-, and m and n each independently represent O or 1. ) represents the central skeleton (core) part of a liquid crystal molecule.

Particularly preferably, in the general formula (A), X is the general formula (
E) YI represents a fluorine atom, a chlorine atom, a cyano group, a methyl group, or a methoxy group, and ZIZ! or Z
3 is each independently a single bond, -COO-0COCHtOO
CH, -CLCFIt- vertically hydrogen atom, fluorine atom,
Although it represents a chlorine atom or a cyano group, yz and Y3 do not represent a hydrogen atom at the same time. zI zt and m represent the same as above. ) is a compound represented by

The SC base liquid crystal in the present invention is characterized by comprising a medium temperature range base liquid crystal and a high temperature liquid crystal.

The medium-temperature range host liquid crystal referred to here means that the liquid crystal compound constituting it is optically inactive and has a two- or three-ring structure, and in the case of a three-ring structure, at least one ring is a cyclohexyl ring. and consists of a compound exhibiting an SC phase or a homologue that differs only in the number of carbon atoms and shape of its alkyl chain, and at least one compound among the homologs exhibits an SC phase at any temperature of 1°C or higher at 10°C or higher. It is a compound that exhibits an SC phase that may be monotropic over a temperature range of . However, in the case of a three-ring structure, it is a liquid crystal whose upper limit temperature of the SC phase is less than 90°C, and exhibits an SC phase that may be monotropic at any temperature range of 10"C or more in 10°C to SO'C. It is something.

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

(1-a) (1-a-23) (1-a-24) (1-a-25) (1-a-26) 4 Shin) R,0COR.

Ya-Ruga RIO0COR2 R1 color - 0 COR2 R, 0 drops buy red 0 CORt (1-a-27) R, Coo ((Defense 1FoR2 (I-a-29) 0CO$ ORZ -N (1-b) (I b-15) R, (defense C00 (gi0COR2 (I b-17) R10 (defense C00 (sawa 0 COR.

ρ (I-b-20) R,COO+coo(to0CORZ (1-c) (1-c-5) R, O+COO shoe C006 (1-c-7) RsO+C00+Rz (1-c-8) RIO-@-Coo-@-0R1 (1-c-10) R, o+coo-@ warm COOR1 (1-c-12) R,0((beC00(warmOCORg (1-d) (1-d-7) (1-d-8) (1-d-9) (1-d-10) (1-d-11) (1-d-12) (1-d-13) (1-d-14) RIO + Coo shoes COSRC 05R+COO-@-COSRg R+0+CO3-@-COORz R+O-@-CO3+OCORg R80-@-Coo (C warm SR.

RIO + COO meeting 5R1 R, S-@-Coo-4 warm R8 R, S-@-Coo ((tears Oh (1-e) (I -e-1) (1-e-2) <r-r>That's all Among the compounds of the formula (1
-a) and compounds represented by formula (1-b) are preferred, and compounds represented by formula (1-a-1), formula (I-a-2), and formula (1-a-
5), compounds represented by formula (1-a-41), ii(1-a-42) and formula (1-b-1) are particularly preferred.

The SC base liquid crystal used in the present invention contains a 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.

(III) High-temperature liquid crystal The high-temperature liquid crystal referred to here refers to an optically inactive compound that mainly consists of a three-ring structure or more rings and exhibits an SC phase, its homolog, or a composition consisting of these. A compound that exhibits an SC phase has an upper limit temperature of 90"C or higher and exhibits an SC phase in a temperature range of at least 5 degrees Celsius or higher, and its homologues have an upper limit temperature of 90"C or higher. The temperature may be less than 90°C, the temperature range may be less than 5°C, or the SC phase may be monotropic, and the composition has an upper limit temperature of 90°C. That's at least 5
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.

/ (1-a) (I[-b) (In-c) (III-b-16) (1! [-b-17) R1 Nizawa φRz R, Nisawa ΦOR1 (1-b-19) (III-b-20) b-23) b-24) R, C00-C Umdate (ha) R.

Rr　COObe'niΣ@-R- RICOO-@-@Σ-@-R.

8 moxibustion 0 COR2 RI i OCOR2 R1 Beg run missing τ lower Σ? ζΣΣOCOR2(m −c−
27) (01-c-28) (I[[-c-29) (III-c-30) (III-c-31) (III-c-32) R, →(:'=co=== ==〒#しにん=::ν１＜→
≠=:===Koji==]: N<EKH Gigantari>RlR, So Makoto Hajime or OR.

-mOR- R, Sourizawa φ0COR1 R1 Soreizawa 0COR1 RIG So (SawaφR8 Hat e) (I[I-f) Hat g) (III-h) (III-4) (u[-1-19 ) (III-i-20) (n[-1-21) (III-i-22) R, COO and PA protection CH Akane 4shi R8 R, C00℃ protection CllCl! <H R1R1ΦYnaC
H*CHzD C00R1R1be3=Intermediate3=U-Cf
ltC1h<EΣC0OR.

(III-i-24) (I[l-1-25) (Ill-i-26) 1110$CIItCH()COOR2R10-'Cable CHtCH*@C00RzR,04beggar)be3=now-
CH, CH, <3ΣΣC0OR.

(III-k) (III-1) (■ ni-6) R1(C wing C1120()C00◎Oh(I[[-ni-
8) RrOoCII! O+ OCO◎ORz<m- to R, O-q Feather CH20 ((shicoΦdoor2(■ to R3<E Feather CHzO(ico◎R2 (■ to -13) ( Feather OCH!()COO◎R2 ( III-m) Compounds having the following heterocycles can also be used as high-temperature liquid crystals.In addition, fluorine atoms, chlorine atoms, or Compounds substituted with cyano groups can also be used as high temperature liquid crystals.

([[-s+-65) R8 origin BA(HA) coo()OCORl (m -m-66> R, COO ancestor BE(HA) coo()R1 (III-n) (Ill -m-97) ( m -m-98) (III -m-99) (III-m-100) (I[[-n+-101) (DI -1102) R1□coo+n2 R1(X)COO-@rOR2 RIOh COO-IF5; ')-R2H, Oa co
o-, ('5')-0R21 times 4coo-@-0COR
2 RICOO$ coo+, 1?2 (III-m-104) RI(xCOO-iνOR2 (n[-n-21) (III-n-22) (I[[-n-23) (I[ l-n-24) (m -n-25) (in-26) (II -n-27) (I[[-n-28) R10aOCO(C2 R10%0CO-@-0R- R,0 Yato5)-0CO-@)-0COR2R,coo
(奸5)-oco-@-R.

R0 bag R1 elephant Y stubborn coco () OR2 N R, 0xx0CO()R1 R,0 (■ n-53) R, 挺8 moxibustion 0CO (いCOR.

(I[I -n-54) COO#0CO-@-R2 (■ R, Oya Ba(ha)OCO-@-0R2 (■ n-60) R,COOya Ba moxibustion coco-@-122 (III -n~85) (In-n-86) (III-n-87) (III-n-88) (III-n-89) (III-n-90) (III-n-91) (I[ l-n-92) R1℃+0CO-@-R2 R1>0CO-@-0R- R,0℃+0CO-@'-R- R,0℃+0CO-@-0R2 RI%0CO-@'-0COR2 RlCOOa oco+ 'h R,aOCO-@-R- p1℃x moxibustion oco+oR- (III-o42) (II[-o-13) (I[l-o-14) (III-o-15) (1-o -16) R,CooΦH,0) C1l□O發R2R,<HFig.5
co, o-@-R.

R1℃Fig.C]1□03OR2 R10℃ twin 5Lcu, o-@-R.

R80(Fig.C”!O(CiR2 (I [I　-o-45) (III-o-46) (nl-o-47) (DI-o-48) RtO 1℃ and tO()Rz RIO<G@-C”-0-@-OR.

R3<D(prevention co, o((prevention 0C06 R, coo(β-@-CH-0-@-R-o-77) o-78) o-79) o-80) R1$ C11zO(Q) -0CORzl1IcOO$
CIIZO(0'l-"ZR,, -C: Europe DC++,
o Ito R2a, 4 birds (Shiyama 0 <ρΣO1'12 (■ p) (■ (■ ρ-29) p-30) R, COO -33) R10 (Ax Basin""-@-"- (DI -p-35) (III-p-36) R1 (Ba-def 0C11□(Si0COR.

R, COO (m-p-61) (III-p-62) (III-p-63) (I[[-p-64) (II-p-65) (I[[-p-66) (m-p-67) (III-p-68) R1 progenitor (c) OCR, -<feather R2 R1 progenitor (9) OCH! G　Rz R, 0 ancestor moxibustion OCH, ■R2 R,0 sobe moxibustion 0C11□Kushi 0R2 R3 ancestor Peor 0CHzD 0CORt R, COO progenitor■0CHtD R2 R1(ba(ha)OC((□■R2 R, seven bars φoCH2G OR1 (m-p-93) (m-p-943 (I[l-p-95) (I[l-p-96) (III-p-97) (■−ρ−98) (■−ρ−99) (DI-p-100) R10% ocL-@-RZ p, oa　0C1l□+aRt Rlp　0C12@)-0CORZ R, C00n 0CH2-@”-R2 R7@-@-0CH2 building R2 R11OC1!2% 0R2 R, o@-@-ocu, +R.

R, o> ocu2+ oRz (III-q) (m-q-17) (m-q-18) (I[[-q-19) (m -q-20) (lI[-q-21) ( m -q-22) (III-q-23) (III-q-24) R grave → ni=7 cicadas==giant==]) and -<cicada 51=n → CH, CI! (Two = Mi≠===Raku>0COR.

1? , COO and IcHICH-DR- RIm Cf1zCH) Rz Rlm Cl2CH2 Tatami 0R2 R+Om C112CIIt()R2 R10% CIIzCflz+0Rz R,0℃4cu,co,()ocoR2R,coo(R
5) -co□C1l□Order R2 (m -q-49) (K -q-50) (III -q-51) (m -q-52) (III -q-53) (Ill-q-54 ) (III-q-55) (DI-q-56) RI (R moxibustion C) IgcHz combination R2 R8C moxibustion CHICHz + ORt R,0! φCHzCHz ((Ji 2 R3 中擾SO◇)山C1l□Xφ)OR.

R, Nishiyama Cl12beφ>0COR.

R, coo (ugly■C11□CH2()R2rashXmoxibustion () R,Cl2CIl□ R2 Mourning b) and the compound represented by the formula (I[I-c) are preferred, and the compounds represented by the formula (Ill-a-1), the formula (III-a-2), and the formula (II
I-a-13), formula (III-b-1), formula (III-
Particularly preferred are compounds represented by c-1) and ii(II[-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 in S01.
A liquid crystal composition can be obtained.

The chiral dopant used in the present invention includes (1) S
A compound exhibiting a C" phase, (2) a compound exhibiting only a liquid crystal phase other than the SC" phase, or (3) a compound exhibiting no liquid crystallinity at all can be used; however, in the case of (3), the SC matrix In order to prevent the tendency for the liquid crystallinity of the SC" liquid crystal composition obtained by adding it to liquid crystal to decrease, it is preferable to use a compound having a skeleton similar to that of liquid crystal.

Among the various physical properties that the chiral dopant brings to the S09 liquid crystal composition, the important ones are the helical pitch it induces, the direction and magnitude of spontaneous polarization, and these are determined by the optically active sites 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.

CH3 (IV 1 ) + CH2−+−1−CHC
Ja (IV-7) CH3 -f-CHI -)7 CH-Ih (IV-2) CHl -OfCHz-+T-CHCzHs (IV-3) CH.

+ CHzh-0+ lx +r C)I Czll
s(IV-12) CH.

-CHRa (IV-13) l13 -C1h-CHCHHz 0Rs (IV-14) CH3 -C1l　Cf1z　0Rs (IV-32) CH3 0-CI-R.

(IV-21) CH2 1-S + CHt +rCH(C)lz)i-CB:1
(IV-57) ClO(Jlz CFI Rs ([V-53) Clt.

C8-0 R1 (IV-55) OCR1CI R5 (IV-62) C.F.

0-C8 (IV-64) 10 Hi Clt-C8-CIl□=OR.

(IV-65) Hff -0-C)l CH, -OR.

(IV-66) LO-(-co,-h-C)l(CH2)-ORB(IV
-ti'7) -COOCHx CM L;HL;z+isH
3 C1h In each of the above general formulas, % and m represent an integer of 1 to 4,
n represents an integer of 1-10, and P has 3 to 8 carbon atoms.
R4 represents an alkyl group having 2 to 10 carbon atoms, R2 represents an alkyl group having 1 to 10 carbon atoms, and R8 represents an alkyl group having 1 to 4 carbon atoms.

Optically active compounds containing only optically active groups represented by formulas (IV-1) to (IV-22) are induced when added to an SC matrix liquid crystal to form an SC* liquid crystal composition. The spontaneous polarization is very small, and even when the SCI phase is exhibited alone, most of the spontaneous polarizations are only 10 nC/cm'' 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 1) 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 the sc'' phase alone, it has a polarization of 300 There are some that show large values of nC7cm'' or more.

In the present invention, as one optically active group that induces strong spontaneous polarization, an optically active group represented by formula (IV-43) is selected, and the other optically active group-2), formula (IV-5)
, formula (rV-6), formula (IV-7), formula (IV-8
), 2 (IV-9), formula (IV-10), formula (IV-1
2) , Formula (IV-15) , Formula (IV-16) , Formula (IV-19) , Formula (IV-20) , Formula (IV-3
1) and an optically active group represented by formula (IV-32).

Since it is very small compared to the spontaneous polarization due to the expressed optically active group, it is not necessary to align the directions.
Only the direction of the helical pitch needs to be considered.

The direction of the helical pitch due to the optically active group represented by is,
- The opposite is preferable for boat fishing, in which case it is also possible to obtain one with a very long helical pitch, but for purposes such as adjusting the helical pinch, a very short helical pitch is required. In such a case, it is preferable that the direction of the helical pitch is the same in both cases.

Typical basic skeletons (X in general formula (A)) of optically active compounds having such an optically active group at the end are listed below.

(V-18) 4) 0Σ Mountain CI! , -@ (V-42) Yuhi 0ba collar (V-66) -〇 Punishment (V-90) ■X image ) *) OCR, Ya 8 Europe (V-210) -0be>OCH-() (V-234) 茳■東OCR,-()Now (V-446) ■Misu (V-447) Tatami coo Ya Hiss (V-448) Go coco Ya inciting body (V ■CItO founder→enter (V ■OCR, (3)Yso＼ (V-451) Bag ■ Eight people (V-479) Go coo Lin (V -501) + [phase] ... insertion (■ bag '5) - cllfO 赫 (V Yashimatoshi 0 CII said person (V-504) Summon R moxibustion coo 挾体 (V-505) Suibe now oco Matsusu (V-506) Standing
Each basic skeleton substituted with a bromine atom, methyl group, methoxy group, cyano group or nitro group can also be used. In particular, basic skeletons substituted with fluorine atoms 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 fluorine is substituted on their benzene rings are preferred; ),
Formula (V-7) ~ Formula (V-9), Formula (V-17), (V
-18L formula (V-21), formula (V-22) or formula (V-
25) The basic skeleton represented by formula (V-27,4) is particularly preferred.

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

of/ / ! ρ- In the above, C is a crystalline phase, No is a chiral nematic phase, S^
is smectic A phase, S01 is chiral smectic C phase, S8 is smectic B phase, S is smectic E phase,
SX, S, and f each represent a smectic phase of unknown origin; those whose phase transition temperature is not stated cannot be measured because they are crystallized, and those whose melting point is not stated cannot be measured because they do not crystallize. It is.

The advantages of using the compound represented by the general formula (A) as a component of a chiral dopant are as follows:
The following can be mentioned.

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

That is, the above compound and the following general formula (F) (wherein R'',
Z'', X, C- and R' have the same meanings as in the case of general formula (A). Under the same conditions, the compound represented by the general formula (A) is 1
0 to 30 nC/cm'' or more, and a value larger than the simple sum of the spontaneous polarization values due to the chiral groups on both sides can be obtained.

When used as a chiral dopant, the larger the spontaneous polarization it induces, the smaller the amount required, so the proportion of the low-viscosity SC host liquid crystal can be increased, making it possible to reduce the viscosity of the S00 liquid crystal composition. This results in improved responsiveness.

(It is possible to adjust the helical pitch, such as compounds with very long helical pitches and compounds with very short helical pitches that induce the 21N" phase or sc" phase.

As mentioned above, in order to obtain good orientation, it is important that the helical pitch in the N0 phase or SC* phase is long. It is sufficient that the helical pitch of the chiral dopant is adjusted as a whole, and this is not necessarily necessary for each individual compound. is easy. Furthermore, in the case of a compound added primarily for the purpose of adjusting the helical pitch, the shorter the helical pinch, the more convenient 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 25% 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-535),
A compound in which any two or one chiral group represented by formulas (IV-1) to (IV-91) are bonded as a side chain can be used.

It is appropriate that the above chiral dopant (excluding the compound of general formula (A)) be added to the SC matrix liquid crystal in a proportion of 1 to 60% by weight and used as an SC1 liquid crystal composition. Preferably, it is added in a proportion of 2 to 50% by weight. The addition ratio of chiral dopant is 6
When the amount is more than 0% by weight, the spontaneous polarization increases, but since the chiral dopant itself has a much higher viscosity than the base liquid crystal, the viscosity of the SC″′ liquid crystal composition becomes thicker (and as a result, the high-speed response This is undesirable because it tends to have an adverse effect on the chiral dopant.In addition, increasing the amount of the chiral dopant added tends to shorten the helical pitch and therefore have an adverse effect on the orientation.On the other hand, the addition ratio of the chiral dopant is undesirable. However, if the mass production of INNs is small, the spontaneous polarization will be 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 in the range of m", and in the case of a chiral dopant exhibiting an sc" phase, it alone exhibits a spontaneous polarization of about 100 nC/cm", or 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%, with
In the case of a chiral dopant that exhibits a strong spontaneous polarization of cn'' or more, the addition ratio of the chiral dopant is preferably in the range of 2 to 25% by weight. The stronger the spontaneous polarization induced by the chiral dopant, the lower the most desirable addition ratio. However, in the chiral dopants made of the optically active compounds exemplified, the addition ratio is never less than 1% by weight.

When the SC" 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 SC0 phase, but at that time, The temperature range exhibiting the N9 phase is preferably 3° or more and less than 30″. If the temperature range showing the N1 phase is less than 3°, the phase transition to the SA phase will occur immediately when the temperature decreases.
The N9 phase tends to make it difficult to align liquid crystal molecules sufficiently, which is not preferable. In addition, the temperature range showing the N'' phase is 30
If it is higher than that, the clearing point of the sc liquid crystal composition becomes high, which tends to have an adverse effect on workability in the step of filling the cell with liquid crystal material, which is not preferable.

Regardless of whether the chiral dopant itself has liquid crystallinity, when added to the SC base liquid crystal, (1) it tends to expand the temperature range in which it exhibits the N'' phase, or it tends to expand the temperature range in which it exhibits the (21N''phase); Each has unique properties, such as those that tend to reduce the temperature range.
0 In order to adjust the temperature range in which the N* phase of the liquid crystal composition is exhibited to the above-mentioned preferred range, in the case of fl), an SC base liquid crystal having a narrow temperature range in which the N phase is exhibited, or an SC which 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 N1 phase but also to the SA phase and the S01 phase. For example, the chiral dopant expands only the SA phase of the S01 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 may 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-I phase; or S
It is sufficient to use a phase sequence in which the temperature range of the A phase is narrow and the phase sequence is SC phase-3A phase-N phase-I phase.

This tendency of chiral dopants can be easily determined by measuring the change in phase transition temperature of an SC liquid crystal composition obtained by adding a certain amount of chiral dopant to an SC matrix liquid crystal. Therefore, the temperature range in which each phase in the S00 liquid crystal composition exhibits, particularly the N1 phase, can be easily adjusted.

Further, it is preferable that the helical pitch appearing in the N" phase from the temperature at which the N1 phase transitions to the SA phase or SC" phase (the lower limit temperature of the N" phase) to the 1" high temperature side is 3 μm or more, An S00 liquid crystal composition in which the helical pitch is 10 μm 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,
It is possible to obtain an S01 liquid crystal composition with a long helical pitch that satisfies the above conditions even with a single compound; however, if the chiral dopant concentration is within a practical range for boat fishing, does not necessarily satisfy the above conditions.

In that case, in order to adjust the helical pitch to the above-mentioned preferred range, it is necessary to add optically active compounds whose helical directions that appear in the N0 phase are opposite to each other when added to the SC base liquid crystal to form an SC1 liquid crystal composition. It is necessary to prepare chiral dopants by adding at least one type at a time.

The helical pitch P (μm) appearing in the N0 phase of the S08 liquid crystal composition containing multiple optically active compounds is determined by the concentration of each optically active substance being C1% and the helical pitch per unit concentration being Pi
(μm) (Here, the right-handed spiral pitch is positive and the left-handed spiral pitch is negative.) Using this, SC1
When Pl at 5A-N" point T0 of the liquid crystal composition is P-, Ci should be selected so that Pl is N
Measurement can be performed by adding a unit concentration of each optically active compound to the SC matrix liquid crystal having a phase.

In reality, To changes depending on each Ci, 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 of ΣCi. If the estimated value T0 and the To of the composition selected using it are significantly different, T
, I and then measure again using To.

The chiral dopane (4) used in the present invention needs to be added to a certain amount of SA matrix liquid crystal to induce a certain level of spontaneous polarization (hereinafter abbreviated as P3).

As mentioned above, for the S01 liquid crystal composition, the amount of chiral dopant added may be adjusted so that the value of P is in the range of 3 to 30 nC/cxa'', especially near room temperature.
However, when the value of P induced by the chiral dopant is small, the amount added is large relative to the SC base liquid crystal, and the viscosity of the S08 liquid crystal composition increases accordingly, resulting in a high-speed response. This is not preferable because it tends to make it difficult to obtain the desired characteristics. Therefore, when the chiral dopant used in the present invention is added to the SC base liquid crystal in an amount of 10% by weight, 1. It is preferable to use a substance that can induce P of 0.5 nC/cn or more when added at 5% by weight.
Particularly preferred are those that can induce P of cm'' or more.

〔Example〕

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, "%" is % by weight.
represents. 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 (D
SC) was used in combination.

Example 1 10% of the compound of the above formula (Vl-27) (even if it is alone, the helical pitch induced in the N0 phase is very long) was used as the medium temperature range host liquid crystal, and the above general formula (1-a-1) S01 liquid crystal composition consisting of 25.7% 25.7% and 20.6% of the compound represented by ρ 18.0% of the compound represented by the general formula (III-a-1) as a high temperature liquid crystal was prepared.

This SC* liquid crystal composition has an SC" phase at 70°C or lower, and
It exhibited an AS phase at temperatures below 1.5°C, an N1 phase at temperatures below 86°C, and became an isotropic liquid (N phase) at temperatures above these.

Next, this SC* liquid crystal composition was filled into a glass cell having a thickness of about 2 μm which had been subjected to an alignment treatment (polyimide coating/rubbing), and when it was slowly cooled from the (2) phase, it exhibited good alignment.

In this cell, the electric field strength I Q VP-P / μm,
When a 50 Hz rectangular wave was applied and the electro-optical response speed was measured, it showed a fast response of 85 μsec at 30° C., and the contrast was also good.

〔Effect of the invention〕

The ferroelectric liquid crystal composition of the present invention is a liquid crystal material that has excellent alignment properties and high-speed response, and can operate in a wide temperature range including room temperature.

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.

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) A ferroelectric liquid crystal composition with the addition of a chiral dopant, where the chiral dopant has the general formula (A) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, R^a is a carbon atom] represents an alkyl group having from 2 to 10 carbon atoms, R^b represents an alkyl group having from 1 to 10 carbon atoms, and l represents an integer from 0 to 10; Z^a is -O-, -
It represents COO-, -OCO- or a single bond, and when Z^a represents -O- or -COO-, l represents an integer from 1 to 10. C^* and C^*^* are each independently (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 in a wide temperature range including room temperature, which is characterized by containing a compound represented by the following. 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.▼, and Y
^2 and Y^3 each independently represent a hydrogen atom, a fluorine atom,
It represents a chlorine atom or a cyano group, but Y^2 and Y^3 do not represent a hydrogen atom at the same time. Z^1, Z^2 and m are the same as those described in claim 1. 2. The ferroelectric liquid crystal composition according to claim 1, wherein the central skeleton (core) portion 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.