JPH02311593A - Ferroelectric liquid crystal composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition showing an SC phase over a wide temperature range including room temperature by incorporating a chiral dopant comprising an optically active compound into an SC base liquid crystal which contains a high- temperature liquid crystal and an intermediate-temperature liquid crystal containing a specified compound. CONSTITUTION:The subject composition is obtained by incorporating a chiral dopant into a liquid crystal composition showing an SC phase and containing an intermediate- temperature liquid crystal (a) showing an SC phase and containing an optically inactive bicyclic compound showing an SC phase, wherein said compound may be monotropic in a temperature range wider than 1 deg.C at 10 deg.C or above, and a specified tricyclic or tetracyclic optically inactive, high-temperature liquid crystal (b). Said liquid crystal (a) is represented by formula I, II or III (wherein R<1> to R<5> are each 1 to 20C alkyl or alkoxy). Said chiral dopant contains an optically active compound of formula IV [wherein Q<1>* and Q<2>* are each a different optically active group containing an asymmetric carbon atom, and one of them has an asymmetric carbon atom directly attached to O, S, N, etc.; Z is a core part of a crystalline molecule of formula V (wherein the groups of formulas VI, VII, and VIII are each a group of any one of formulas IX, X, etc.; Y<1> and Y<2> are each a single bond, COO, SCO, etc.; (m) is 0 or 1)].

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] Currently, the liquid crystal display elements that are widely used are mainly of the TN type, which utilizes nematic liquid crystals, and although they have many advantages, their responsiveness is inferior to that of CRTs, etc. The major drawback was that it was much slower than the light-emitting display method. 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 bistability, 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, thin TVs, etc., and research and development is currently being conducted in various fields to put it into practical use.

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 an SC phase (hereinafter referred to as SC compounds) have been studied, and many compounds have already been synthesized. However, these SC
The two compounds alone meet the following conditions for use as optical switching elements for ferroelectric liquid crystal displays: (a) exhibiting ferroelectricity over a wide temperature range including room temperature; and (b) having appropriate phase stability in a high temperature range. Having a series (c) In particular, chiral nematic C and the following will be abbreviated as N1.

) exhibiting a long helical pitch in the phase; (d) having an appropriate tilt angle; (e) having low viscosity; (f) having a large value of spontaneous polarization above a certain level. As a result of (1), (e) and (f), there is no known material that satisfies all of the following: (1) exhibiting good orientation, (5) and (f) exhibiting high-speed responsiveness.

Therefore, the current situation is that liquid crystal compositions exhibiting the S01 phase (hereinafter referred to as SC'' liquid crystal compositions) are used for study purposes and the like.

In order to obtain good orientation, for example, JP-A-61-1
As shown in Japanese Patent No. 53623, etc., in a liquid crystal having an N'' phase in the high temperature range of the SC0 phase, a method of increasing the helical pitch of the N1 phase is generally effective. The orientation is better when the smectic A (hereinafter abbreviated as SA) phase is present in the temperature range between the "phase" and "N" phase, and in order to increase the helical pitch, an optically active substance that produces left-handed helix is used. It is also known that it is possible to use a combination of an optically active compound that produces a right-handed helix. (Adjusting the alignment is already a known technique.) However, although these techniques can provide good orientation, they do not necessarily provide high-speed response.

In order to exhibit high-speed response, for example, as shown in the special lecture at the 12th Liquid Crystal Conference (Proceedings of the same conference P, 9B), low viscosity smectic C (hereinafter abbreviated as SCa) is required. A parent liquid crystal composition exhibiting a phase (hereinafter referred to as SC parent liquid crystal) has spontaneous polarization (hereinafter abbreviated as P).

) 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.

Further, 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 provides a liquid crystal composition (
Hereinafter, it will be referred to as the SC matrix liquid crystal used in the present invention. ), and a chiral dopant consisting of an optically active compound is added to the ferroelectric liquid crystal composition, in particular, the medium temperature range liquid crystal has the following general formula (A-1), (A-2) or (A- 3) A ferroelectric material containing at least one compound represented by 3), in which the chiral dopant contains an optically active compound represented by the following general formula (B), and exhibiting an SC° phase in a wide temperature range including room temperature. The present invention provides a transparent liquid crystal composition.

General formula (A-1) (wherein R'' and Rb each independently have 1 to 2 carbon atoms
0 represents a straight chain or branched alkyl group or alkoxyl group, and at least one of R" and RbO represents an alkoxyl group. One of R" and Rb represents a straight chain having 3 to 12 carbon atoms. It is preferable that one group represents a straight-chain alkyl group and the other represents a straight-chain or branched alkoxyl group having 3 to 12 carbon atoms. ) General formula (A-2) (wherein, RC and R6 each independently have 1 to 2 carbon atoms
0 represents a straight-chain or branched alkyl group or alkoxyl group, and at least one of Rc and R'' represents an alkoxyl group. Of R' and Rd, one represents a straight-chain or branched alkyl group or an alkoxyl group having 3 to 12 carbon atoms. It is preferable that one represents a chain alkyl group and the other represents a straight or branched alkoxyl group having 3 to 12 carbon atoms.) General formula (A-3) (wherein R'' and Rt are each independently 1-2 carbon atoms in
0 represents a linear or branched alkyl group or an alkoxyl group, and at least one of R@ and Rf represents an alkoxyl group. General formula (B ) Ql-Z Qt" ... (B) [In the formula, Ql 1= and Q 1m are mutually different optically active groups, and each optically active group has at least one asymmetric carbon atom. , and at least one of the groups Ql" and Q" has a structure in which an asymmetric carbon atom is directly bonded to oxygen, iodine, nitrogen, fluorine, chlorine, -C- or -CEN. Z represents a structure in which any one or two hydrogen atoms on these rings are substituted with a fluorine atom or a cyano group; however, in a structure in which the above hydrogen atoms are substituted with a fluorine atom or a cyano group, and yz are each independently a single bond, -COO-1-0
CO-1-coio-1OCH2-5-CH, CI+,
-1-C=C-1-COS- or -5CO-, preferably a single bond, -COO-1-0CO-1-CH,0- or -0CH2-, and when m=1 It is preferable that at least one of Y' and yz is a single bond. ) represents the central skeleton (core) part of a liquid crystal molecule. ] In the present invention, in order to obtain faster response, S
The C matrix liquid crystal has the configuration shown below.

That is, (■) a composition consisting of a compound having a two-ring structure and exhibiting an SC phase at a temperature close to room temperature, or a homolog thereof (a compound that differs only in the alkyl chain) (hereinafter referred to as a medium-temperature liquid crystal).
(■) A compound having a ring structure of 3 or more rings and having a large effect of increasing the TC point (representing the upper limit temperature of the SC phase or sc'' phase) when added to a medium-temperature liquid crystal, or its analogues. This is a composition in which a composition consisting of liquid crystal (hereinafter referred to as high-temperature liquid crystal) is added.

The medium-temperature liquid crystal used in the present invention is one in which the liquid crystal compound constituting it is optically inactive, has a two-ring structure, and has an S
A compound exhibiting C phase or the number of carbon atoms in its alkyl chain,
It consists of homologs that differ only in shape, and at least one compound among the homologues is a compound that exhibits an SC phase that may be monotropic at any temperature range of 1°C or higher at 10°C or higher.

In particular, in the present invention, the medium temperature range liquid crystal has the general formula (A-
1), (A-2) or (A-3).

In addition to the compounds represented by the general formulas (A-1), (A-2) and (A-3), compounds represented by the following general formula (D) or (E) are also used as the medium temperature range liquid crystal. be able to.

General formula CD) (In the formula, R9 and Rh each independently have 1 to 1 carbon atoms.
20 straight-chain or branched alkyl, alkoxyl, alkoxycarbonyl, alkanoyloxy, alkoxycarbonyloxy, alkenyl, alkenyloxy, alkenyloxycarbonyl, alkenylcarbonyloxy or alkenyloxycarbonyloxy group, at least one of which is alkyl Represents a group other than a group or an alkenyl group.

represents. However, compounds represented by general formulas (A-1) and (A-2) are excluded.

General formula (E) U is -coo-, -oco-, -cos-, -5co-
Or represents -C=C-. However, the compound represented by general formula (A-3) is excluded. ) The high-temperature liquid crystal used in the present invention is an optically inactive compound having a three- or four-ring structure, or a composition thereof, and each compound is an S
The upper limit temperature of C phase (hereinafter abbreviated as Tc) is 50 to 6
When mixed at 10% in a composition at 0°C, its Tc is 1.5
Preferably, at least two rings are aromatic rings (1,4-phenylene, pyrimidine-2,
5-diyl, pyrazine-2,5-diyl, pyridine-2
, 5-diyl or its fluorine substituted product), and T
It is characterized by being a compound in which c is 90°C or more and the temperature range of the SC phase is 5°C or more, or a homologue with a different number of carbon atoms or shape of the alkyl group in the side chain. That is.

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.

(II [-a) 4 small 19) R, C00 (possible φ to CI (, CH
R2(III-i-20) RICOOeCH2CIh
0R1 ([[-1-21) R+ and abusive CH, CH(
)COORz(I[[-1-24) R10(simply φ>
CH, Yama■cooRz(III-D (II[-k) (Ifr-ni-6) l?, (feather CH□0()COO
GOR.

(nI-ni-8) Rho ((wings CHzO()OC
OG ORt(III-ni-10) p, o((wing CH
,ObesoΣoco■R2(I[[-ni-12) R1-
4 birds Cl1zO()oco(shiR2(III-ni-13
) R, ((feather0C112()COOG R2(1-
ffi) The following compounds having heterocycles can also be used as high-temperature liquid crystals. Further, 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.

(II[-m) (■Shi65) R+4 tower (law coobe subΣ0COR
z (■-Toro 6) R, coo correction pzugΣΣcoo
((ΣΣR2(III-m-97) R,3唖)-coosha Rz(DI-m-98) R,ecoo
shaoR.

(III-m-101) Rt m CoO< OC
ORz(III-m-102) R,COOmC00(
)R.

(I[I-n) 1121) p, o
I[l-n-23) RrOWOCO()OCOR2
(III-n-24) R, coo<bow+OCO<φ
>R.

(m -n-25) RI>OCObeφ>R2N (I[l-n-26) p,%oco4)op2N cap-n-27) R+ 0% OCObe)OR2N (Ill-n-28) R , o>oco()oR2(
I[[-n-53) R regret Y()OCO-@-0C
OR-N Overba (ha) 4 birds (In -n-57) RIOOCORZ Fuba ■ (
) (I[I-n-58) Rho
OCOORz (nl-n-91) RI$0CO (defense'! (II[-o) (m-0-9> R, 0 (h) CI12q) RZ hat-〇-10) p, o (Oki, Q ) CII, 01Σ0R2(
III-o-11) R+f sound ICIIzq) OCOR
zゝCtsu”Ntey (III-o-12) R+CQO+, Q) CIlzO
(φ>Rz(”-0-13) R10CH2'-@-R
2(I[[-o-14) R+ M CItzOXφ
X0Rz(■-0-15) R103CH2'-@-R
2(nr -o-16) R+ 0 < CII zO
X Minister XORz (m -p-29) R, #OCH□■
0COR2(III-p-30) R, COO and %oCH, GR.

(I[[-p-31) R, (lip-protectionocnz()Rt
(III-p-32) R, + Defense 0C11□ (R2
(I[l-p-33) R, 0 is 0C11□GR2
(I [I -p-34) R, 0 + Defense OC1 + 2 ■ 0
R2 (III-p-35) Rt Exclude 0CII Z
■0COR2 (III-p-36) R, COO
Defense OCH4) R2 (m-p-61) R+Sobe Φ0C
Rz■R2 (DI-p-66) R+COO progenitor ◇0
CH2■R2(I[[-p-93) R,o<弼Pa过し0CII□SHAR2(I[-p-94) R,o<guba(law OCR!Ichi)-oR.

Cap = p-95) R (Guba Docr+, +0COR
z(III-p-96) R+COO% 0CII
Be5) -p-(I[I-f'-97) R11OC1
h-@rRZ (III-p-98) Laocobe 5
>oR.

(III-p-99) R10% 0Clz+Rz(
III-p-100) R,0 (moxibustion coco2+ORz
(III-q) (III-q-17) Rr (weight cH2CHz(
)ocORZN (m -q-18) R, COOM CHzCHz combination R
2(III-q-19) Rr kΣCH2CH2
φXRZ(m-q-20) RrmCHzCHi)O
Rz (rfi-q-21) Rr0 # Cf (zCl
t+ RZ(l[I-q-22) RIOeCl(2C
H-)OR2(I[[-q-23) Rr0 + CH
zCII attack>0COR.

(III-q-24) RrCOOya)-@-C”□C
H28R2 (III -q-49) R+ <Gubatev CH2Cl+ (A> R2H (II[-q-54) p, coo>C11□Yamabegi>Rzhat-q-85)R1<E Teshiyama CIlbeson R2 (I[-q-86) Rle CHzCllz
(QtoR2(nI-Q-87) R+Om CtlzC
HzD Rz(III-q-88) R,0? C1
l□CHz■OI? Among two or more compounds, the formula (I[I
-a), formula (I[[-b), formula (I[[-c), formula (I
[[-f), formula (I[[-h), formula (II[-m),
Formula (I[[-n), Formula (I[[-o) and Formula (III-
Particularly preferred are compounds represented by p).

The blending ratio of the medium temperature range liquid crystal is preferably 1 to 90% by weight, particularly preferably 10 to 75% by weight of the SC base liquid crystal. If the proportion of the high-temperature liquid crystal is too small, the Tc cannot be made sufficiently high, and if it is too large, the viscosity increases. Therefore, the proportion of the high-temperature liquid crystal is preferably 3 to 60% by weight, preferably 5 to 50% by weight of the SC base liquid crystal. .

It is preferable that the compound represented by the above general formulas (A-1), (A-2) and (A-3) is contained in the medium temperature range liquid crystal in an amount of 30% by weight or more, particularly 50% by weight or more.

The SC matrix liquid crystal used in the present invention has a phase sequence of (a) I (isotropic liquid) phase → N phase → SA phase → SC phase on the high temperature side of its SC phase when the temperature is lowered (b) (iii) Those with a phase sequence of phase → 5AI-1-3C phase; (c) Those with a phase sequence of ■ phase → N phase → SC phase; or (d) Those with a phase sequence of I phase → SC phase. Those having a phase series are used, and the selection of (a) to (d) differs depending on the chiral dopant used at the same time and the preferred phase series when used in the SC9 liquid crystal composition. The most commonly used method is (a), in which the chiral dopant is
When a chiral dopant is added to a C matrix liquid crystal, there is a strong tendency to widen the temperature range of the N" phase and narrow the temperature range of the SA phase, etc., and when a chiral dopant is added to an SC matrix liquid crystal, If there is a strong tendency to widen the temperature range of the SA phase and narrow the temperature range of the N'' phase, use (c).
It is most suitable to use (d) when the C property is weak and the temperature range of the N* phase or SA phase is likely to be widened. What is important is the phase series in the case of an SC* liquid crystal composition, and generally, the phase series I-N"→5A-3C" is advantageous in terms of orientation. On the other hand, the phase series "■→N1→sc" may also exhibit better alignment depending on the orientation control method, and a large tilt angle can be easily obtained, so it is suitable for the guest-host system.

In addition, the phase series ■→SA→S06 is also the initial ferroelectric liquid crystal (p-decyloxybenzylidene aminosilicate (S)-
2-methylbutyl, etc.) had this phase series, the orientation method has been well studied, and it is not impossible to obtain good orientation.

The chiral dopant used in the present invention includes (1) S
It is possible to use a compound that exhibits a C phase, (2) a compound that exhibits only a liquid crystal phase other than the SC phase, or (3) a compound that exhibits no liquid crystallinity at all. In the case of (3), the SC base liquid crystal In order to prevent a tendency for the liquid crystallinity of the SC0 liquid crystal composition obtained by adding the liquid crystal to a liquid crystal composition 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 a chiral dopant brings to the SC4 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 dovants, SC2 compounds, or additives to nematic liquid crystals are listed below.

CIl3 1・ (IV-1) +CHz+rCH-cz)Is1
・ (IV-2) -0-(-CI□-)j-CHC
JsCI+3 1 monkey (IV-3) (-C11□)i-0+CH2-
+-1-011-C2H2CI+3 1 cell (IV-4) -0(-C1lzh-0+CHz
+rC1lCzllsOC1h Ill.

(R76) -0-C+CIIz+1-CHCz
HsCl(3 1* (TV-7) ÷CHz -)i-C)l -R
3Hi (・ (IV 8) -0+CILz÷-CHR3H
3 1* (IV-12) -CH-R4 1 Monkey (IV 13) -CHz-Ctl CH
z ORslh 1* (IV-14) -CIl-CHz-OR5H
3 1. (IV-21) -5-(-CI+□+-1-C
H(C)1. Te CH.

I3 1・ (IV-32) -0-CH-R.

C11゜1・(IV -53) C1l ORs(IV
−)4J −L; −υ−L; H, −L; H−
hs(IV-55) -0-C1l□-CIl
Rs1 Monkey (IV 57) OCHt C1l
RsOCF3 II + (TV-61) -C-0-CIl-R9Fff 1・ (IV -62) OCHRsH3 I・ (rV 64) OC1h Cll
C1l□-0RSH3 1・ (rv-js)-0-C8-CIl2-0R5H3 1 happiness (TV-66) -0-(-C1l□÷rclI
(CI+□)-OR.

(IV 67) C00CHz l
;II to II 1;21151 umbrella (IV -69) -COOCH2□-C1l
RsH3 1. (IV-70) -0-CO, -CH-Cl+
2-OCORsCH.

1 Monkey (IV 71) OCll C11z
OC0R5H3 1. (IV 72) OC1l C) Iz
(C)I2) TOCORsCH! 1. (■ 73) OCHz-CH-iC11
□)7-ocoI? .

1. (IV-75) -0-CIl□-CH-0R5
H3 1. (IV-76) -5-C1l-R52H5 1. (rV 7B) OCl12 Ctl
OR & (IV -79) H to -0-C-0-
-BI4 (IV 80) COOCH2C1
l R5CN 1. (IV-81) -0-CH2-CI-R.

CN 1・ (IV 82) CHR5Cl1□CN 1・ (IV 83) COOCHz C1l
R5Cl1. CN 1. (IV-84) -0-CIl□-CH-R5 Hz In each of the above general formulas, m represents an integer from 1 to 4,
represents an integer of 1 to 10, R3 represents an alkyl group having 3 to 8 carbon atoms, R4 represents an alkyl group having 2 to 10 carbon atoms, and R6 represents an alkyl group having 1 to 10 carbon atoms. , R6 represents an alkyl group having 1 to 4 carbon atoms.

In optically active compounds containing only the optically active groups represented by formulas (IV-1) to (IV-22) as optically active groups, when added to the SC base liquid crystal to form an SC"liquid crystal composition, Spontaneous polarization is often small, and SC1 alone
Even when a phase is exhibited, most of the phases are only 10 nC/cm'' or less.

On the other hand, as optically active groups, formulas (IV-31) to (■-9
Many of the optically active compounds containing the optically active group represented by 1) induce a large spontaneous polarization when added to the SC matrix liquid crystal to form an SC'' liquid crystal composition, and when used alone, they induce a large amount of spontaneous polarization.
In some cases, such as when exhibiting a phase, a large value of 300 nC/cm'' or more exists.

Typical basic skeletons of optically active compounds having such an optically active group at the end are listed below.

< v-24) -0Xc=c -0oco-0(■Tsukuda0
Zetsuto CO No. (V-486) Shaocn, Matsusu Each of the above basic skeletons in which the benzene ring or cyclohexane ring is substituted with a fluorine atom, chlorine atom, bromine atom, methyl group, methoxy group, cyano group or nitro group Basic skeletons can also be used.

The optically active compound having the chiral group bonded to one or both sides of the basic skeleton as described above can be effectively used as a constituent component of a chiral dopant. Particularly preferred is an optically active compound represented by the general formula (B) in which the chiral groups are bonded to both sides.

In the optically active compound represented by general formula (B), in particular, at least one optically active group is as described in (TV-31)
It is desirable that it be any of the groups represented by -(TV-91).

As described above, the following points can be cited as advantages of using an optically active compound in which different chiral groups are bonded to both sides of the basic skeleton.

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

That is, a chiral group selected from the groups represented by (TV-31) to (IV-91) above and (IV-1) to (IV-2
2) A compound having chiral groups selected from the groups represented by (IV-31) to (■-91) on both sides of the basic skeleton, and a compound having the same basic skeleton with chiral groups selected from the groups represented by (IV-31) to (■-91). Compounds with only one group and an achiral group on the other side are added to the SC base liquid crystal, and when the spontaneous polarization is determined as an extrapolated value, it is found that the compound with chiral groups on both sides is 10 to 30 nC /cm" or more. Since the spontaneous polarization derived from the groups represented by (IV-1) to (IV-22) is at most about 10 nC/cm, it is larger than the simple sum of the spontaneous polarization due to the chiral groups on both sides. It can be seen that it is also getting larger.

Furthermore, in a compound that is a group selected from the groups represented by (IV-31) to (IV-91) and has different chiral groups on both sides of the basic skeleton, the spontaneous polarization due to both chiral groups is Polar ((S)-2-methylbutyl b-decyloxybenzylidene aminophenyl cinnamate (DOBAMBC), a well-known ferroelectric liquid crystal)
The polarity of is determined as e. ), a very large spontaneous polarization can be obtained.

In this case, a larger spontaneous polarization of 100 nC7cm'' or more can be obtained than the simple sum of the spontaneous polarizations due to the chiral groups on both sides.

As a chiral dopant, the larger the spontaneous polarization that can be induced, the smaller the amount of chiral dopant needed to be used.
The proportion of C matrix liquid crystal can be increased, and as a result, s
c” It is possible to lower the viscosity of the liquid crystal composition. As a result,
This leads to improved responsiveness.

(2) Compounds with a very long helical pitch induced in the N'' phase or SC'' phase, and compounds with a very short helical pitch, etc.
It is possible to adjust the helical pitch.

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 as a whole is adjusted, Although this is not necessarily the case for individual compounds, it is easier to adjust the helical pitch if the main component of the chiral dopant has a somewhat longer helical pitch.In addition, for compounds added with the main purpose of adjusting the helical pitch, the helical pitch can be adjusted more easily. The shorter the pitch, the more advantageous it is possible to suppress the amount of addition.

In order to lengthen the helical pitch, the directions of the helical pitch due to the chiral groups on both sides should be opposite to each other, but (IV-31
) to (IV-91), it is preferable that the polarities of their spontaneous polarizations be the same.

(3) Particularly (IV-31) ~ which can show large spontaneous polarization
Chiral groups selected from the groups represented by (IV-91) obtained by chemical methods such as asymmetric synthesis and optical resolution often do not have 100% optical purity; It is quite difficult to refine these to 100□%. However, obtained from natural products (S
)-2-Methylbutanol or a chiral group with extremely high optical purity such as those obtained by microbial engineering techniques, these become diastereomers, making it difficult to separate them by chromatography or recrystallization. This makes it easy to achieve optical purity close to 100%.

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

-a Among the compounds of formula (B), compounds having particularly preferable combinations of basic skeleton and chiral group are shown below.

In the above general formula, R4 and R41 each independently represent an alkyl group having 2 to 10 carbon atoms, R3, R, and r each independently represent an alkyl group having 1 to 10 carbon atoms,
R7 is a linear alkyl group having 2 to 10 carbon atoms, a branched alkyl group having 3 to 10 carbon atoms, or an optically active group having at least one asymmetric carbon having 4 to 10 carbon atoms. represents an alkyl group, i represents an integer of 0 to 5,
Y is a single bond, -o-, -oco-, -coo-, or -
ocoo -, W is chlorine fluorine or -〇-C
Represents H3 and Z' is COO, OCO, CHzO, 0CHz-9 or alone.

XI and X4 each independently represent a hydrogen atom, a fluorine atom or a cyano group, X2 represents a hydrogen atom or XI,
X3 represents a hydrogen atom or X4, and at least one of X4 represents a hydrogen atom.

The above chiral dopant is present in the SC matrix liquid crystal at 1 to 60%.
It is appropriate to add it in a proportion of 2% by weight and use it as an SC9 liquid crystal composition, but it is more preferable to add it in a proportion of 2 to 50% by weight. If the addition ratio of the chiral dopant is more than 60% by weight, the spontaneous polarization will increase, but since the chiral dopant itself has a much higher viscosity than the base liquid crystal, the viscosity of the SC* liquid crystal composition will increase, resulting in This is not preferable because it tends to adversely affect high-speed response. 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.

The spontaneous polarization value of the S01 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 T112, and in the case of a chiral dopant exhibiting the S01 phase, it alone exhibits spontaneous polarization of about 100 nC/cm'' or an intensity equivalent to that. For chiral dopants that induce spontaneous polarization,
The addition ratio of the chiral dopant is preferably in the range of 10 to 40 weight %, and in the case of a chiral dopant exhibiting strong spontaneous polarization of 300 nC7cm'' or more, the addition ratio of the chiral dopant is preferably in the range of 2 to 25 weight %. The stronger the spontaneous polarization induced by the chiral dopant, the lower its most desirable addition ratio will be.However, if the value of P8 induced by the chiral dopant is small, the amount added will increase relative to the SC host liquid crystal, and this SC*
This is not preferable because the viscosity of the liquid crystal composition increases, and as a result, high-speed response tends to be difficult to obtain. 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. OnC/cm”
It is preferable to use a material that can induce a P of 0.5 nC/cm '' or more when added in an amount of 5% by weight.

When the S01 liquid crystal composition of the present invention is cooled from an isotropic liquid state, it undergoes a phase transition to the SC9 phase via the N1 phase, the SA phase, or the N* phase and the SA phase.
N from the phase transition temperature from the phase to the SA phase (hereinafter referred to as the N''-3A point) to one degree higher than the N''-3A point.
“SC in which the pitch of the spiral appearing in the phase is 3 μm or more”
More preferably, the liquid crystal composition has a spiral pitch of 10 μm.
Above, an SC* liquid crystal composition in which the pitch of the helix increases divergently as it approaches the N''-3A point is particularly preferred.

The temperature range in which the S01 liquid crystal composition of the present invention exhibits the N'' phase is as follows:
A range of 3 degrees or more and less than 30 degrees is preferable.

If the temperature range in which the N'' phase is exhibited is less than 3 degrees, it is not preferable because the phase transition to the SA phase occurs immediately when the temperature decreases, making it difficult to sufficiently align liquid crystal molecules in the N* phase. If the temperature range exhibiting the N''' phase is 30 degrees or higher, the clearing point of the SC* liquid crystal composition becomes high, which tends to adversely affect workability in the step of filling the cell with the liquid crystal material, etc.

Chiral dopants are those that tend to (1) expand the temperature range in which the N" phase is exhibited, or (2) N" when added to the SC host liquid crystal, regardless of whether the chiral dopant itself has liquid crystallinity or not. Each has unique properties, such as those that tend to narrow the temperature range in which they exhibit a phase. SC 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 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 N9 phase but also to the SA phase and S08 phase. For example, the chiral dopant expands only the SA phase of the SC umbrella liquid crystal composition, and the N1 phase and S
In the case of reducing the C1 phase, 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 → I 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.

Such a tendency of the chiral dopant can be easily determined by measuring the change in the phase transition temperature of the S09 liquid crystal composition obtained by adding a certain amount of the chiral dopant to the SC base liquid crystal. From this result, the temperature range in which each phase in the SC* liquid crystal composition exhibits, particularly the N* phase, can be easily adjusted.

Among the optically active compounds of general formula (B), in compounds in which the helical directions induced in the N'' phase by the chiral groups RI''+R2'' on both sides are opposite to each other, the induced helical pitch is quite long. Therefore, when using such a compound as the main component of a chiral dopant, adjusting the helical pitch is often unnecessary or easy, but generally the helical pitch can be lengthened as follows. Can be adjusted.

The pitch P (μm) of the helix appearing in the N'' phase of the S01 liquid crystal composition containing multiple optically active compounds is determined by Ci representing the concentration of each optically active substance and Pi representing the pitch of the helix per unit concentration of each optically active substance.
(μm) (here, the right-handed spiral pitch is positive and the left-handed spiral pitch is negative), and using this, S00
When the pt at the 5A-N" point T0 of the liquid crystal composition is P7, Ci should be selected such that Pi is the unit concentration of each optically active compound added to the SC base liquid crystal having an N phase. Measurement is possible by doing this.

In reality, To changes depending on each Ci, but it can often be inferred 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 ΣC3. If the value 71.1 and To of the composition selected using it are significantly different, the measurement may be performed again using To instead of T0'.

〔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, r%J 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 (D
SC) was used in combination.

Example 1 A compound represented by the general formula (A-1) as a medium-temperature liquid crystal, a compound represented by the general formula (III-a-1) as a high-temperature liquid crystal, and a chiral dopant. -1) An SC'' liquid crystal composition consisting of 13.1% was prepared.

This 5011 liquid crystal composition has a sc" phase at 68°C or lower, and a 7
It exhibited an sA phase at temperatures below 0.5°C, a TeN'' phase at temperatures below 77.5°C, and became an isotropic liquid phase at temperatures above that.
The liquid crystal composition was filled into a cell having a thickness of about 2 μm and consisting of two glass transparent electrodes that had been subjected to an orientation treatment by polyimide coating and rubbing, and slowly cooled from the ■ phase to room temperature. The orientation was good, and a uniform SC" phase monodomain was obtained.

This cell has an electric field strength of 10 VF-P/tl m, 5
When a 0 Hz square wave was applied and the electro-optical response speed was measured, a high-speed response of 46 μsec at 25° C. was confirmed. The spontaneous polarization at this time is 13.4nC/cm",
The tilt angle was 25.9'' and the contrast was very good.

Example 2 From the compound represented by the above general formula (A-2) as a medium temperature range liquid crystal 2264% 22.4% From the compound represented by the above general formula Cm-a-1) as a high temperature liquid crystal and as a chiral dopant , SC consisting of 14.6% of the compound of formula (R-1) and 5.4% of the compound of formula (L-1)
“A liquid crystal composition was prepared.

As in Example 1, the phase transition temperature and electro-optical response speed of this S01 liquid crystal composition are shown in Table 1. (below,
Similarly) Example 3 In Example 2, as the medium temperature range liquid crystal, the general formula (A
An S07 liquid crystal composition was prepared in the same manner as in Example 1, except that 9.6% and 11.2% of the compound represented by -1) were used.

Example 4 20% of the compound represented by the general formula (A-1) as a medium-temperature liquid crystal 20% of the compound of the general formula (A-3) as a high-temperature liquid crystal 20% of the compound represented by the general formula (A-3) as a high-temperature liquid crystal From the compound represented by [1-a-1), the compound represented by 30% and the chiral dopant, the compound represented by (R-2) 6%C
Compound (R-3) represented by H3 12.6%
Compound (L-2) represented by 11.4%
An SC1 liquid crystal composition was prepared.

Example 5 In Example 4, as the high temperature liquid crystal, the general formula (II
Compound 3 from the compounds represented by I-a-13)
An SC'' liquid crystal composition was prepared in the same manner as in Example 4 except that 0% was used.

Example 6 In Example 4, as the high temperature liquid crystal, the general formula (III
Compound 30 from the compounds represented by -a-10)
A S01 liquid crystal composition was prepared in the same manner as in Example 4 except that % was used.

Example 7 In Example 4, as the high temperature liquid crystal, the general formula (II
Compound 3 from the compound represented by I-f-42)
A S01 liquid crystal composition was prepared in the same manner as in Example 4 except that 0% was used.

Example 8 As a medium temperature range liquid crystal, from the compound represented by the general formula (A-2), from the general formula (A-3), 6.4% of the compound 6.4% of the compound of the formula (A-3) 6.4% of the compound represented by the above general formula (Tr[-a-1) as a high temperature liquid crystal, and as a chiral dopant the compound of the above formula (R-1) 14.6% of the above formula (L -1
An S01 liquid crystal composition was prepared comprising 5.4% of the compound of

Example 9 In Example 8, the above general formula (A-
1) From the compound represented by the general formula (A-2), 6.7
% 6.7% 5.8% And from the compound represented by the general formula (A-3), the compound 6.4% 6.4% compound 6.4% A S09 liquid crystal composition was prepared in the same manner as in Example 8, except that the composition was used.

〔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) (a) has a two-ring structure and is optically inactive,
A compound exhibiting a smectic C phase, or a composition consisting of homologues differing only in the number or shape of carbon atoms in the alkyl group of the side chain, at least one of the homologs
The seed compound is a medium-temperature liquid crystal that exhibits a smectic C phase that may be monotropic in a temperature range of 1°C or more above 10°C, and (b) an optical compound consisting of a 3- or 4-ring structure. A chemically inert compound or a composition comprising the same,
When each compound constituting the composition is added in an amount of 10% by weight to a composition in which the upper limit temperature of the smectic C phase consisting of the medium temperature range liquid crystal is 50 to 60°C, the upper limit temperature of the smectic C phase is 1.5°C. (2
) A ferroelectric liquid crystal composition containing a chiral dopant, wherein the medium-temperature liquid crystal has the following general formula (A-1), (A-2) or (A-3).
A ferroelectric liquid crystal composition exhibiting a chiral smectic C phase in a wide temperature range including room temperature, characterized in that the chiral dopant contains an optically active compound represented by the following general formula (B). . General formula (A-1) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼ General formula (A-2) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼ General formula (A-3) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R^a, R^b, R^c, R^d, R^e and R^f are each independently a linear or branched alkyl group having 1 to 20 carbon atoms, or Represents an alkoxyl group, R
^a and R^b, R^c and R^d, R^e and R^f
At least one of them represents an alkoxyl group. ) General formula (B) Q^1^*-Z-Q^2^* [In the formula, Q^1^* and Q^2^* are mutually different optically active groups, and each optically active group is A group having at least one asymmetric carbon atom and at least one of Q^1^* and Q^2^* is a group in which the asymmetric carbon atom is oxygen, sulfur, nitrogen, fluorine, chlorine, or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or has a structure directly connected to -C≡N. Z
is a general formula (C) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas,
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. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼
or represents a structure in which any one or two hydrogen atoms on these rings are substituted with a fluorine atom or a cyano group, and Y^1 and Y^2 each independently represent a single bond, -COO-, -OCO- , -CH_
2O-, -OCH_2-, -CH_2CH_2-, -C
≡C-, -COS- or -SCO-, and m represents 0 or 1. ) represents the central skeleton (core) part of a liquid crystal molecule. 2. The strong liquid crystal according to claim 1, characterized in that the medium temperature range liquid crystal contains a compound represented by general formula (A-1) and a compound represented by general formula (A-2) according to claim 1. Dielectric liquid crystal composition. 3. The ferroelectric according to claim 1, wherein the medium temperature range liquid crystal contains a compound represented by the general formula (A-1) and a compound represented by the general formula (A-3) according to claim 1. liquid crystal composition. 4. The ferroelectric according to claim 1, wherein the medium temperature range liquid crystal contains a compound represented by the general formula (A-2) and a compound represented by the general formula (A-3) according to claim 1. liquid crystal composition. 5. The medium temperature range liquid crystal contains a compound represented by the general formula (A-1), a compound represented by the general formula (A-2), and a compound represented by the general formula (A-3) according to claim 1. The ferroelectric liquid crystal composition according to claim 1, characterized in that: