JPH03182590A - Ferroelectric liquid crystal composition - Google Patents

Abstract

PURPOSE:To obtain the title composition showing a chiral smectic C phase over a wide temperature range including room temperature and improved in raped response characteristics and orientation properties by incorporating a chiral dopant into a base liquid crystal containing three specified compounds. CONSTITUTION:A compound (i) selected from among those of formulas I, II, III, etc., (wherein R<a> and R<b> are each straight-chain or branched alkyl or alkoxyl, provided that at least one of them is alkoxyl) is mixed with a compound (ii) selected from among those of formulas IV, V, etc., (wherein the group of formula VI is a group of any one of formulas VII to X; R<c> and R<d> are each straight-chain or branched alkyl, provided that at least one of them is straight- chain alkyl) and a compound (iii) of formula XI (wherein R<e> is 1-18C straight- chain or branched alkyl or alkoxyl; R<f> is 1-20C straight-chain or branched alkyl; the group of formula XII is of formulas, VII, IX, etc., and the group of formula XIII is of formula VII, X, etc., provided that at least one of the group of formula XII and the group of formula XIII is of formula VII) to give an optically inactive base liquid crystal (A) showing a smectic C phase. A chiral dopant (B) comprising an optically active compound is incorporated into component A.

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 smectink 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 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 ferroelectric liquid crystals belongs to the tilted chiral smectic phase, and among these, the one that is practically desirable is the chiral smectic C (hereinafter abbreviated as SC1) phase, which has the lowest viscosity. It is called.

[Problem to be solved by the invention]

Liquid crystal compounds exhibiting an SC0 phase (hereinafter referred to as SC0 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) exhibiting ferroelectricity over a wide temperature range including room temperature; and (b) having appropriate phase stability in a high temperature range. (c) exhibiting a long helical pitch, especially in the chiral nematic (hereinafter abbreviated as N′″) phase (d) having an appropriate tilt angle (e) having low viscosity (f) spontaneous Polarization must be a large value to a certain extent; Furthermore, it must exhibit good orientation as a result of (g), (b) and (c); and (ch) it must exhibit high-speed responsiveness as a result of (e) and (f). Nothing was known that would satisfy all of the above.

Therefore, the current situation is that liquid crystal compositions exhibiting an SC'' phase (hereinafter referred to as SC1 liquid crystal compositions) are 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 N0 phase in the high temperature range of the SC1 phase, a method of increasing the helical pitch length of the N'''' 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 N3 phase, the orientation will be better, and in order to increase the helical pitch, a left-handed helix should be generated. It is also known that an optically active substance and an optically active compound that causes 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 (abbreviated as N) liquid crystal.) However, some of these techniques do not provide good results. Although orientation can be obtained,
High-speed response could not be 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). ) Parent liquid crystal set that shows the phase! IFI (hereinafter referred to as SC
It is called the mother liquid crystal. ), an excellent method is to add an SC" compound with a large spontaneous polarization (hereinafter abbreviated as P). According to this method, the proportion of the optically active compound that produces a helix is reduced, so The helical pitch is relatively long, but if you try to make the helical pitch long enough to obtain good orientation, it is necessary to add a small amount of optically active compound, and as a result, the spontaneous polarization becomes too small, making it difficult to obtain high-speed response. There was a problem that disappeared.

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 m-oxide which is fully satisfactory in both high-speed response and orientation.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides chiral smectic C obtained by adding a chiral dopant made of an optically active compound to a matrix liquid crystal that is optically inactive and exhibits a smectic C phase (hereinafter referred to as SC matrix liquid crystal). A liquid crystal composition exhibiting a phase, wherein the parent liquid crystal has (1) the following general formula (A-1), (A-2), (A-3).
, (A-4) and (A-5>), (2) the following general formula (B-1
), (B-2), (B-3) and (B-4), and (3) containing a compound represented by the following general formula (C). Provided is a ferroelectric liquid crystal composition exhibiting a xylsmectic C phase over a wide temperature range including room temperature.

General formula (A-1) General formula ( ) General formula (A-3) General formula (A-4) General formula (A-5) (In the above general formula (A-1) '-(A-5), R”
and R5 each independently represent a linear or branched alkyl group or alkoxyl group having 1 to 2 carbon atoms,
At least one group among R1 and R2 represents an alkoxyl group, and preferably one group among R1 and R2 represents a straight-chain alkyl group having 4 to 12 carbon atoms, and the other group represents an alkyl group having 4 to 12 carbon atoms. represents a linear or branched alkoxyl group having 4 to 12 carbon atoms. > General formula (B-1) General formula (B-2) General formula ( ) General formula (B-4) (In the above general formulas (B-1) to (B-4), Rc and R
Each of 6 independently represents a linear or branched alkyl group having 1 to 18 carbon atoms, and at least one group among Ro and R4 represents a linear alkyl group, preferably Rc and R'' each independently represents a linear alkyl group having 4 to 12 carbon atoms, represented by the general formula (C) (wherein R'' is a linear or branched alkyl group or alkoxyl group having 1 to 18 carbon atoms) , preferably a linear or methyl branched alkyl group having 3 to 12 carbon atoms.

Rf represents a straight chain or branched alkyl group having 1 to 20 carbon atoms, preferably a straight chain or methyl branched alkyl group having 3 to 12 carbon atoms.

represents a group.

vinegar.

Compounds belonging to Group A are compounds that exhibit an SC phase at or near room temperature, or their homologues (compounds that differ only in the number of carbon atoms in the alkyl chain and/or its shape), and the viscosity is Although it is a medium-sized compound, it largely contributes to expanding the temperature range of the SC phase to a low temperature range. The present invention particularly provides the general formula (A-1), (A
, 2), (A-3), (A-4) or (A-5).

General formulas (A-1), (A, 2), (A-3), (A-4
) and (A-5), more specifically, the following compounds can be mentioned.

Rg@-4toOR' (A31) R904toC00□to0Rh (A-53) Among the compounds represented by general formulas (A-11) to (A-53), general formula (^-11), (A-12), (^-2
1), (A-22), (A-31), (A-32), (
A-41), (A-42), (^-52) and (A-5
Compounds represented by the formula 3) are preferred, and compounds represented by the general formula % are particularly preferred.

As compounds having properties similar to the compounds belonging to Group A, the following compounds (1) to (3) may also be included as components of the liquid crystal composition, if necessary.

(1) In general formulas (A-1) to (A-3), at least one of R1 and R is an alkoxycarbonyl, alkanoyloxy, or alkoxycarbonyloxy group, and the other group is an alkyl , alkoxy, alkoxycarbonyl, alkanoyloxy or alkoxycarbonyl group.

(2) A compound represented by the general formulas (A-1) to (A-3) or the above (1), which is an arbitrary -σ node (3) The following general formula (A-4) (A7) A compound represented by

General formula (A-4) (wherein R and R each independently represent an alkyl, alkoxyl, alkylthio, alkoxycarbonyl, alkylthiocarbonyl, alkanoyloxy, or alkoxycarbonyloxy group, but at least one of the groups is not an alkyl group, and may be substituted with F at the 2- or 3-position) general formula (A-5) (wherein, R and RJ have the same meaning as in the general formula (A) and represents the field of 4).

) General formula (A-6) (In the formula, R' and RJ are represented in the general formula (A-4).) General formula (A-7) Same as in the case of the general formula (A, -6) have meaning. ) Compounds belonging to Group B do not exhibit SC phase by themselves or their homologs, but they are very low viscosity compounds, and by adding them to SC1 liquid crystals, they can reduce their viscosity. , which contributes to improving responsiveness.

The present invention particularly provides the general formulas (B-1), (B-2), (
It is characterized by containing at least one compound represented by B-3) or (B-4).

The following compounds can be mentioned as typical compounds belonging to Group B.

(b) Compounds represented by general formula (B-1) In the above table, ・ means that the phase exists, ・ means that it does not exist, and the number to the right of ・ means that the phase changes from that phase to a phase in a higher temperature range. Each transition temperature is shown, and the numbers in parentheses indicate that the phase is monotropic.

Cr is a crystalline phase, SB is a smectic B phase, N is a nematic phase, and ■ is an isotropic liquid phase, but SB is partially SA (
There is also a possibility of smectic A) phase.

(B) Compound represented by general formula (B-2) (c) General formula (B-3) Compound represented by (In the table above, S represents a smectic phase.

〉 (d) Compounds represented by general formula (B-4) These B group compounds may exhibit a tilted smectic phase, an N phase, an SA phase, an SE phase, or an SE (smectic E) phase. In particular, the SC phase is not shown.

Generally, when a compound exhibiting such a phase transition is added to an SC matrix liquid crystal, its Tc (the upper limit temperature of the SC phase) is often significantly lowered, and so far it has rarely been used as a constituent material of the SC matrix liquid crystal. There wasn't. However, by using a compound selected from Group A and Group C, the drop in Tc can be suppressed, and the viscosity of the liquid crystal composition can be lowered, thereby greatly improving responsiveness, especially due to the effect of the compound in Group C. It became possible.

In addition, these compounds differ in their liquid crystallinity depending on the presence or absence of Hun-replacement substitution or the position thereof, especially in the compound represented by the general formula (B (B-3), l) → 5) 4. , If you want to expand the temperature range of the N phase (or N0 phase) of the SC base liquid crystal (or SC'' liquid crystal composition), use the following general compounds as compounds having properties similar to those of group B compounds. A compound represented by formula (B') that does not exhibit an SC phase may also be used in combination.

Rk and RL each independently represent a straight or branched alkyl group having 1 to 18 carbon atoms, preferably a straight chain alkyl group having 4 to 12 carbon atoms.
0CHz-CHzCHt, Cmic-
, -cos --5co- or a single bond. (However, compounds of group B are excluded.) The compound represented by the above general formula (C) shows the SC phase up to a high temperature range, or even if it does not show the SC phase, the Tc (upper limit temperature of the SC phase) By adding it to a low-temperature liquid crystal composition, it has the effect of increasing its Tc, and contributes to expanding the temperature range of the SC phase, especially in the high temperature range,
Specifically, the following compounds can be mentioned.

of (In the table above, SF stands for smectic F phase.

) -m Compounds having similar effects to the compound represented by formula (C) include compounds represented by the following general formula CG). These can be used in combination with the compound represented by general formula (G).

General formula (G) In the formula, R''' and R'' each independently have 1-1 carbon atoms.
8, preferably 3 to 12 linear or branched alkyl groups, and ZI and Z4 each independently represent -coo-
, -oco-, -o-, -s- or a single bond, preferably at least one of them represents a single bond.

Z! and Z are each independently -coo--oco-C
HzO, OCH! COS 5CO-CH
z-CHx-9C represents a C- or a single bond, and at least one is preferably a single bond.

Any 1 to 2 hydrogen atoms in the ring are fluorine (fluorine substituted), and furthermore, in at least one of the SC base liquid crystals used in the present invention, the proportion of the compound of group A is 1 to 2.
The proportion of the compound of group B, which is preferably in the range of 90% by weight, and particularly preferably in the range of 5 to 75% by weight, is 1 to 1. 60! ii% range, especially from 5 to 40
A weight percent range is preferred.

If the proportion of the compound represented by the general formula (C) is too small, the Tc will be low, and if it is too large, the responsiveness will be reduced.
A range of 70% by weight is preferred, especially a range of 10 to 50% by weight.

The SC matrix liquid crystal used in the present invention has a phase sequence of (i) I (isotropic liquid) phase → N phase → SA phase → SC phase on the high temperature side of its SC phase when the temperature is lowered. Either phase has a phase sequence of I phase → SA phase → SC phase (c) has a phase sequence of I phase → N phase → SC phase, or (d) has a phase sequence of I phase → SC phase The selection of (a) to (d) depends on the chiral dopant used at the same time and the preferred phase sequence in the SC1 liquid crystal composition. , (a), and when a chiral dopant is added to the SC base 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., then (b) is the chiral dopant. When added to the SC base liquid crystal, if there is a strong tendency to widen the temperature range of the SA phase and narrow the temperature range of the N0 phase, select (c). It is most suitable to use (d) when it is easy to widen the temperature range of →N0→5A4SC" phase series is advantageous in terms of orientation. On the other hand, I→N0→SC" phase series is advantageous in terms of orientation.
The phase series No. 1 may also exhibit better orientation 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 of 1→5A-3C'' is also similar to the initial ferroelectric liquid crystal (P-decyloxybenzylidene aminocinnamic acid (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
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 SC0 liquid crystal composition obtained by adding it to liquid crystal to decrease, it is preferable to use a compound having a skeleton similar to liquid crystal.

Among the various physical properties that the chiral dopant brings to the SC1 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.

(IV-1) CH.

(-CHr+-r-CHC!Hs (■ 2) C sticker −o+cor÷=CI−CtHs (rV-3) C.I.

+CO! h-0-(-CH!+-CH-CJs(IV-
4> CHl -0fCHzh-0+ CHl, CHCJs(rV-
7) CI.

1・ (-CHt-)TCHRs (IV-13) C11゜ 1 monkey -CH, -CHCHt　0Rs (IV-14) CH.

-CI　CHz　0Rs (rV-21) CH.

-5-(-co1÷yCH(CHt)i-CHs(lV
-4i no u-t;-shin-shii,-t,reshiztls LIV -4HJ-ra■-ji-u-Xs (IV-535 C11°HORs (IV-55) OCHz CHRs (1!i /-57) f O (Jig CHRs (IV-65) CH.

OCHCHz 0Rs (IV-69) 1 -CO0CHz CHRs (IV-70) CH3 1・ OCHz　CHC)It　0CORs(■ 71) C.I.

OCHCHz OC0Rs (■ 72) C.I.

OCI CHz(C1ht, 0CORs(IV-73
) -0-CI.

C11゜ CH-(CH2)T-OCOR.

(■ 80) COOC)It CHRs H3 GH3 In each of the above general formulas, m represents an integer from 1 to 4, and n
represents an integer of 1 to 10, R1 represents an alkyl group having 3 to 8 carbon atoms, R4 represents an alkyl group having 2 to 10 carbon atoms, and R2 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 optically active groups represented by formulas (IV-1) to (IV-22), when added to an SC base liquid crystal to form an SC0 liquid crystal composition, Spontaneous polarization is often small, and SC′
Even when a ``phase'' is exhibited, most of them 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 base liquid crystal to form an SC9 liquid crystal composition, and when used alone, they induce SC'
In some cases, such as those exhibiting a ``phase'', a large value of 300 nC/c1 or more exists.

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

(V-48) Mameto ■ Iu (V-144) OC〇-〇 Baru (V-192) C su)) ocoJ ga (V-480) 沓 oco＾* (V-481) sha CH, 0be* (V-482) sha oco-su (V-483) (E) COO Roki (V 484) Φoco 86 (he-485) Sasa CH, 0 lawsuit≠ (V-486) ΦOCH, be* It is also possible to use basic skeletons in which the benzene ring or cyclohexane ring in each of the above basic skeletons is substituted with a fluorine atom, chlorine atom, bromine atom, methyl group, methoxy group, cyano group, or nitro group.

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. In particular, general formula (D) Q"-Z-Q" in which the chiral groups are bonded to both sides.

[In the formula, Q'' and Qgl are different optically active groups, each optically active group has at least one asymmetric carbon atom, and at least one of Q'' and Q'' The group has a structure in which one asymmetric carbon atom is directly bonded to oxygen, io, nitrogen, fluorine, chlorine, or -C- or CmiN. Represents a structure in which two hydrogen atoms are substituted with fluorine atoms or cyano groups, Yl and Y2 are each independently a single bond, -COO-0COCHzOQC)
It GHzGHzc = c --cos- or -5CO-, and S represents 0 or 1. ) represents the central skeleton (core) part of a liquid crystal molecule. ] Optically active compounds represented by these are preferred.

Furthermore, preferably, the optically active groups Q II and Q 1m are represented by the following general formulas (F-1) and (F-2), respectively.

General formula (F-1) I R1-CH-Y" General formula (F-2) 2 1 fist R" -CH-Y3- (wherein, R1 and Rz each independently have 2 to 1 carbon atoms
0 alkyl group, or an alkoxyl group, alkoxycarbonyl group, or alkanoyloxy group having 1 to 10 carbon atoms, C' represents an asymmetric carbon atom, and Xl and X!
each independently represents C[l, -F-5CZ- or -CN, and Yt and Y3 each independently represent a single bond, -o--c
oo--oco--(-CI!)TT O-(-CHz
)n%+CH2)-i-I-OCO Dou C1, fan or +
CH! )j-T-C00+CH! Represents a fan, 11.1
2, ml, m2, nl and R2 each independently represent an integer of 0 to 5. ) More preferably, the chiral groups are not the same, and at least one of them has an asymmetric carbon atom of oxygen (○),
Sulfur (S), nitrogen (N), fluorine (F), chlorine (C
In particular, the hetero atom such as
It is desirable that it be any of the groups represented by V-31) to (IV-101).

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 only on one side.

That is, a chiral group selected from the groups represented by (IV-31) to (IV-91) 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 /c- or larger. Since the spontaneous polarization derived from the groups represented by (IV-1) to (■-22) is at most about 10 nC/cm2, it can be seen that it is larger than the simple sum of the spontaneous polarization due to the chiral groups on both sides.

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 it can induce, the smaller its amount needs to be used.
The proportion of C matrix liquid crystal can be increased, and as a result, S
It is possible to reduce the viscosity of a C0 liquid crystal. as a result,
This leads to improved responsiveness.

(2) It is possible to adjust the helical pitch, such as a compound with a very long helical pitch or a very short helical pitch induced in the N'' phase or SC0 phase.

As mentioned above, in order to obtain good orientation, it is important that the helical pitch in the N3 phase or SC0 phase is long. It is only necessary that the helical pitch of the chiral dopant is adjusted as a whole, and this is not necessarily necessary for each individual compound, but it is easier to adjust the helical pitch if the main component of the chiral dopant has a somewhat longer helical pitch. It is. Further, in the case of a compound added primarily for the purpose of adjusting the helical pitch, the shorter the helical pitch, the more convenient the amount added can be suppressed.

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 purify these to 100%. However, (S) obtained from natural products
-When combined with a chiral group derived from 2-methylbutanol or a chiral group with extremely high optical purity such as those obtained by microbial engineering techniques, these become diastereomers, which can be easily separated by chromatography or recrystallization. Therefore, the optical purity can be brought 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.

-i 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 R4' each independently represent an alkyl group having 2 to 10 carbon atoms, R1 and R,l each independently represent an alkyl group having 1 to 10 carbon atoms,
R1 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 containing at least one asymmetric carbon having 4 to 10 carbon atoms. represents an alkyl group, l represents an integer of O to 5,
Y is a single bond, -o-, -oco-, -coo-, or -
oco.

, W represents chlorine fluorine or -〇-C)1. and Z' is COO- 0CO CHzO, 0CHz-1 or alone.

XI and X4 each independently represent a hydrogen atom, a fluorine atom or a cyano group, and X! represents a hydrogen atom or XI,
X'' 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 the chiral dopant in an amount of 2% by weight and use it as an "sc" liquid crystal composition, and more preferably in an amount of 2 to 50% by weight.The proportion of the chiral dopant added is more than 60% by weight. , the spontaneous polarization increases, but since the chiral dopant itself has a much higher viscosity than the parent liquid crystal, the viscosity of the SC" liquid crystal composition increases, which tends to have a negative effect on high-speed response. 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.

The value of spontaneous polarization of SC" 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 In the case of a chiral dopant that induces polarization, the addition ratio of the chiral dopant is preferably in the range of 10 to 40% by weight, and 3000C/
cl! In the case of a chiral dopant exhibiting the above-mentioned strong spontaneous polarization, the addition ratio of the chiral dopant is preferably in the range of 2 to 25%. The stronger the spontaneous polarization induced by the chiral dopant, the lower its most desirable addition ratio. However, when the value of P induced by the chiral dopant is small, the amount added becomes large relative to the SC host liquid crystal, and the viscosity of the SC" liquid crystal composition increases accordingly, resulting in a high speed This is not preferable because it tends to make it impossible to obtain responsiveness. Therefore, the chiral dopant used in the present invention is one that can induce P8 of 1.0 nC/C1l'' or more when added to the SC base liquid crystal in an amount of 10% by weight. is preferable, and when added at 5% by weight, 0.5 n
Particularly preferred is one that can induce P of C/cm'' or more.

The SC'' liquid crystal composition of the present invention has an N1 phase, an SA phase, or an N'' phase upon cooling from an isotropic liquid state.
phase and SA phase to SC” phase, but at that time, N
S in which the pitch of the spiral appearing in the N0 phase from the phase transition temperature from the 1st phase to the SA phase (hereinafter referred to as the N''-3A point) to the 1 degree higher temperature side of the H6N 1SA point is 3 μm or more.
C1 liquid crystal structure Kaimono is more preferable, and the pitch of the spiral is 10.
um or more, and an SC0 liquid crystal composition in which the pitch of the spiral increases divergently as it approaches the N''-3A point is particularly preferred.

The temperature range showing the N0 phase of the SC0 liquid crystal composition of the present invention is:
A range of 3 degrees or more and less than 30 degrees is preferable.

If the temperature range in which the N1 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 fully align liquid crystal molecules in the N'' phase. If the temperature range showing the 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.

A chiral dopant, when added to an SC host liquid crystal, regardless of whether or not the chiral dopant itself has liquid crystallinity, either (1) tends to expand the temperature range in which it exhibits the N'' phase, or (2) exhibits the N'' phase. Each has its own unique properties, such as those that tend to narrow the temperature range in which they occur. 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 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 N'' phase but also to the SA phase and SC0 phase. For example, the chiral dopant expands only the SA phase of the SC'' liquid crystal composition, and
In the case of reducing the C''' phase, the upper limit temperature of the SC phase is high and the temperature range of the N phase is wide, as the SC host liquid crystal.
In addition, it is sufficient to use one having a phase sequence of SC phase→N phase→I phase, or one having a phase series of SC phase→SA phase→N phase→I phase in which the temperature range of SA phase is narrow<SC phase→SA 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 base liquid crystal. Therefore, the temperature range showing each phase in the SC0 liquid crystal composition, especially the N' phase, can be easily adjusted.

Among the optically active compounds of general formula (D), in compounds where the directions of the helices 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. , when such a compound is used as the main component of a chiral dopant, helical pitch adjustment is often unnecessary or easy;
- For boat fishing, the spiral pitch can be adjusted to a longer length as follows.

The pitch P (μm) of the helix appearing in the SC2 liquid crystal composition N1 phase containing multiple optically active compounds is defined as the concentration of each optically active substance is C4, and the pitch of the helix per unit concentration is 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 P' at point T0 is PTI, Ci should be selected such that Pi is the S
Measurement can be performed by adding each optically active compound at a unit concentration to the C matrix liquid crystal.

In reality, To changes depending on each Ci, but it can often be estimated quite accurately from the concentration of each optically active compound in the SC matrix liquid crystal, the change in the 5A-N'' point when only ΣCi is added, etc. If the estimated (!T,') 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 with reference to Examples below, but the gist and scope of the present invention are not limited by these 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 (D
SC) was used in combination.

Example 1 A liquid crystal composition (hereinafter referred to as base liquid crystal
) was prepared.

This composition exhibited an SC phase at 57°C or lower, an SA phase at 64.5°C or lower, and an N phase at 69°C or lower, and its melting point was 14°C.

Next, when the SC * liquid crystal IJl or oxide is added to the SC base liquid crystal, a compound with the formula (formula The pitch of the spiral that appears in N"li7 when
is 4.7 μrn at 60″C.) Compound 7
3%, and as a compound that causes the appearance of a left-handed helix, the formula (when this compound is added to the SC matrix liquid crystal (A) at 10%, the helical pitch (extrapolated value) that appears in the N'' phase is 60
It is 11.9 μm at °C. ) to prepare a chiral dopant in which the pitch of the helix appearing in the N0 phase was adjusted.

This chiral dopant is added to the SC base liquid crystal (A) at 1
The spontaneous polarization value of the SC "liquid crystal composition obtained by adding 0% at 25° C." was about 6 nC/cm.

Next, mother liquid crystal (A) 40.0%B
Compound of formula (B-1-1) 4.6% Compound of formula (B-1-2) 4.6% Formula (B-1-3)
) Compound 2.3% Compound (C-1) 1
An SC" liquid crystal composition was prepared consisting of 13.5% of the above chiral luvant compound and 20.0% of the above compound.

This SC0 liquid crystal composition exhibits an SC1 phase at temperatures below 62°C and a
It exhibited an SA phase at temperatures below 3°C and an NI phase at temperatures below 81'C.

This SC liquid crystal composition was filled into a cell with a thickness of approximately 2 μm consisting of two glass transparent electrodes that had been subjected to alignment treatment (polyte coating/rubbing treatment), and was gradually cooled from an isotropic liquid phase to room temperature. When conducted, it showed good orientation,
A homogeneous SC0 phase monodomain was obtained.

This cell has an electric field strength of 10 VP-P/μm, 50 Hz.
When a rectangular wave was applied and the electro-optical response speed was measured, a high-speed response of 62 μsec at 25° C. was confirmed.

The spontaneous polarization was about 18 nC/ctm'' and the contrast was very good.

Examples 2 to 5 In Example 1, in place of the compound of formula (C-1), compounds of formula (C-2), (C-3), (C-4), (C-5), (
The SC1 liquid crystal composition and cell were prepared in the same manner as in Example 1 except that each compound of C-6) was used, and the electro-optic response speed was measured. The results are shown in the table below. Ta.

[Effects of the Invention] The ferroelectric liquid crystal composition of the present invention is a liquid crystal material that has excellent orientation 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.

teenager Reason Man

Claims (1)

[Scope of Claims] 1. A liquid crystal composition exhibiting a chiral smectic C phase obtained by adding a chiral dopant consisting of an optically active compound to a matrix liquid crystal that is optically inactive and exhibiting a smectic C phase, wherein the matrix liquid crystal is , (1) The following general formulas (A-1), (A-2), (A-3)
, a compound selected from Group A consisting of compounds represented by (A-4) and (A-5), (2) the following general formulas (B-1), (B-2), (B-3)
and (B-4), and (3) a compound represented by the following general formula (C). A ferroelectric liquid crystal composition exhibiting a phase. 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. ▼ General formula (A-4) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ General formula (A-5) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (General formulas (A-1) to (A-5) above) Medium, R^a and R
Each ^b independently represents a linear or branched alkyl group or alkoxyl group having 1 to 20 carbon atoms, but R^
At least one of a and R^b represents an alkoxyl group. ) General formula (B-1) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼ General formula (B-2) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼ General formula (B-3) ▲ Contains mathematical formulas, chemical formulas, tables, etc. Yes ▼ General formula (B-4) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the above general formulas (B-1) to (B-4), R^c and R
^d each independently represents a linear or branched alkyl group having 1 to 18 carbon atoms, and at least one group among R^c and R^d represents a straight alkyl group, ▲
There are mathematical formulas, chemical formulas, tables, etc. ▼ is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ Mathematical formulas, tables, etc. ▼ represents ▲, there are mathematical formulas, chemical formulas, tables, etc.▼ means ▲ there are mathematical formulas, chemical formulas, 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 mathematical formula, chemical formula, table, etc. ▼. ) General formula (C) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^e represents a linear or branched alkyl group or alkoxyl group having 1 to 18 carbon atoms, and R^f Represents a linear or branched alkyl group having 1 to 20 carbon atoms, and includes ▲mathematical formulas, chemical formulas, tables, etc.▼ means ▲mathematical formulas,
There are 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 mathematical formula, chemical formula, table, etc., and ▲ represents a mathematical formula,
There are chemical formulas, tables, etc. ▼ is ▲ 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.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼, but ▲There are mathematical formulas, chemical formulas, tables, etc.▼ and ▲Mathematical formulas There are , chemical formulas, tables, etc. ▼, at least one of which represents ▲ there are mathematical formulas, chemical formulas, tables, etc. ▼. 2. The ferroelectric liquid crystal composition according to claim 1, wherein group A comprises a compound represented by general formula (A-1). 3. Group B has general formulas (B-1), (B-2) and (B-3
3. The ferroelectric liquid crystal composition according to claim 1 or 2, wherein the ferroelectric liquid crystal composition is composed of a compound represented by the following formula, and ▲ has a mathematical formula, chemical formula, table, etc. ▼ ▲ has a mathematical formula, chemical formula, table, etc. ▼. 4. ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas , there are chemical formulas, tables, etc. ▼, ▲ there are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ there are mathematical formulas, chemical formulas, tables, etc. ▼ Claims 1 and 2
Or the ferroelectric liquid crystal composition according to 3. 5. The ferroelectric liquid crystal according to claim 1, 2 or 3, wherein ▲There are mathematical formulas, chemical formulas, tables, etc.▼ and ▲There are mathematical formulas, chemical formulas, tables, etc.▼ are both ▲There are mathematical formulas, chemical formulas, tables, etc.▼ Composition. 6. The chiral dopant has the general formula (D) Q^1^*-Z-Q^2^* [In the formula, Q^1^* and Q^2^* are mutually different optically active groups, and each The optically active group has at least one asymmetric carbon atom, and in at least one of Q^1^* and Q^2^*, the asymmetric carbon atom is oxygen, sulfur, nitrogen, or fluorine. , chlorine or ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or Z, which has a structure directly connected to -C≡N
is a general formula (E) ▲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 s represents 0 or 1. ) represents the central skeleton (core) part of a liquid crystal molecule. ] Claims 1, 2, containing an optically active compound represented by
The ferroelectric liquid crystal composition according to 3, 4 or 5. 7. Q^1^* is an optically active group represented by the following general formula (F-1), and Q^2^* is an optically active group represented by the following general formula (F-2). The ferroelectric liquid crystal composition described above. General formula (F-1) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ General formula (F-2) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R^1 and R^2 each independently Number of carbon atoms: 2
~10 alkyl group, or an alkoxyl group, alkoxycarbonyl group, or alkanoyloxy group having 1 to 10 carbon atoms, C^* represents an asymmetric carbon atom, and X^1
and X^2 each independently represent CH_3-, F-, Cl- or -CN, and Y^2 and Y^3 each independently represent a single bond, -O-, -COO-, -OCO-, Represents ▲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 l1
, l2, m1, m2, n1 and n2 are each independently 0 to
Represents an integer of 5. )