JPH02196887A - Ferroelectric liquid crystal composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition exhibiting ferroelectricity, having excellent response and memory performance and useful as an electro-optical display material by adding a chiral dopant composed of an optically active compound to a specific smectic liquid crystal composition. CONSTITUTION:The objective composition is produced by adding (A) a chiral dopant of formula [X is skeleton; at least one of R and R is optically active group containing one or more hetero-atoms] to (B) an optically inactive medium- temperature range matrix liquid crystal composed of (i) a liquid crystal having bicyclic structure and exhibiting smectic C phase and (ii) a liquid crystal compound having tricyclic structure containing cyclohexyl ring and exhibiting smectic C phase and (C) an optically inactive liquid crystal composition having an upper limit temperature of smectic C phase of >=90 deg.C and composed of (iii) a liquid crystal compound, etc., having a ring structure containing >=3 rings and exhibiting smectic C phase.

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.

[Conventional technology]

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

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

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

[Problem to be solved by the invention]

Liquid crystal compounds exhibiting an SC''' phase (hereinafter referred to as SC0 compounds) have been studied and many compounds have already been synthesized.
The 00 compound alone meets 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) exhibiting appropriate phase stability in a high temperature range. (b) Particularly chiral nematic (hereinafter abbreviated as No).

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

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

In order to obtain good orientation, for example, JP-A-61-1
As shown in Japanese Patent Application No. 53623, etc., in a liquid crystal having an N'' phase in the high temperature range of the sc'' phase, a method of increasing the helical pitch length of the N1 phase is generally effective. In this case, if the smectic A (hereinafter abbreviated as SA) phase is present in the intermediate temperature range between the SC phase and the N0 phase, the orientation will be better. It is also known that it is possible to use a combination of an optically active substance and an optically active compound that generates a right-handed helix. (Adjusting the length to an arbitrary length 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 responsiveness, low-viscosity smectic C (hereinafter abbreviated as SC) is used, for example, as shown in the special lecture at the 12th Liquid Crystal Conference (Proceedings of the same conference P, 9B). ) phase (hereinafter referred to as SC matrix liquid crystal) has a spontaneous polarization (hereinafter abbreviated as Ps).

) is better.

According to this method, the proportion of the optically active compound that produces the helix is small, so the helical pitch is relatively long. need to be,
As a result, the spontaneous polarization became too small, resulting in a problem that high-speed response could not be obtained.

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.

RO+COO沓OR' (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 in addition, compositions containing liquid crystal compounds exhibiting a strong dipole (polarization) in the direction perpendicular to the molecular axis. Therefore, 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-mentioned problems, the present invention provides an SC base liquid crystal consisting of a medium-temperature range base liquid crystal and a high-temperature liquid crystal shown below, using the general formula (
A) A chiral dopant containing a small number of optically active compounds having different chiral groups (one type as a constituent) is added to both chains of the molecule represented by R+"XR2"-(A). SC'''
A liquid crystal composition is provided.

The SC matrix liquid crystal in the present invention is characterized by consisting of a medium-temperature matrix liquid crystal and a high-temperature liquid crystal. , a 2- or 3-ring structure, in the case of a 3-ring structure, at least one ring is a cyclohexyl ring, and the compounds exhibiting an SC phase or differ only in the number of carbon atoms and the shape of their alkyl chains. consisting of homologs, and at least one compound in the homologues is free from any
S may be monotropic within a temperature range of 'C or higher.
This is a compound that exhibits C phase. However, in the case of a three-ring structure, it is a liquid crystal whose upper limit temperature of the SC phase is less than 90°C, and 1
It exhibits an SC phase which may be monotropic in any temperature range of 10°C or more in the range of 0°C to 80°C.

Typical compounds used as intermediate temperature range base materials are listed below. However, in the general formula shown below, R+
, Rz each independently represent an alkyl group having 1 to 18 carbon atoms.

(1-a) (1-b) (I b-23) R,000 tatami COO (XC00Rz (1-c) (Lc RIO+000 (Sawa 0COOR.

(!-C RIO(■coo(YcoOR2 RICOO+C00(Ycoallt (■ R,0CO-4 anti-coo moxibustion COOR2 Rba Shun COO+COOR2 (■ c-48) R, (to coo((def OR.

(1-c-50) R, -(c3)-coo((Defense 0 COR.

(■ c-52) R10iC00 and Totomi (1-d) (1-e) (1-e-1) (1-e-2) (1-d-15) R,S-”Ci00 (turbid oRz (I-d-21) R,0 tatami cos! OR.

-N (■ f) Among the above compounds, compounds represented by formula (1-a) and formula (■-b) are preferred, and formula (1-a-1), formula (
I-a-5), formula (I-a-41) and formula (1-b-1
) are particularly preferred.

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

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

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) (■ b) (■ C) (■ d) (III-e) hat e-9) RIO-0 Pa, Ba or OR.

(■ f) (■ g) (■ h) (III-i) (■ j) (■ k) (■ 0＠COzuDOCII□-GOR2 (III -j R709000℃doorC1l□()h (■ R , @coo◎-0C11□-K, Yu-P2(■ R7◎oco℃door11□0(i2 (III-j R,0@oco-◎C1l□0℃ΣR2(III-1) (U[ -+++) Compounds having the following heterocycles can also be used as high-temperature liquid crystals.In addition, in the compounds having the heterocycles represented by the general formulas below, one fluorine atom, a chlorine atom, or Compounds substituted with cyano groups can also be used as high temperature liquid crystals.

(I[[-m-17) (■-Hagane-18) (III-5-19) (III-+m-20) (m-m-21) (III-m-22) (II[-m-23) (III-m-24) R1 and diagram C00()OCORz R,COOΦSobenCOO-@-Rz R1 and hunting 5>COO-@-R- R6 and 4coo-@-oR2 R,0 and abuse C00-@)-Rt R, 0℃ hunting 5>COO-6OR- RIO% coo()OCORz R,Coo℃X)C00()R2 (III-5i-49) (III-m-50) (m-m-51> (III-s-52) (m-m-53) (m-5r-54) (■---55) (III-5-56) R, (Ba moxibustion C00 (I.

R1(baΦcoo(feather0RI R20-0 moxibustion C00()R.

R,O(paorcoo()ORz R, (layer φC00()OCORt C00(Pa■C00()Rt R.

R,zuXorC00()Rt R,zuXorC00()ORt (III-va (Ill-m ([1-m (I[I-m R, Φx■co 伜R.

R1eCOO Yu)-OR2 R30□ coo-◎-R2 HiN R+Oe COO combination ORz (III-Ro) (■ (■ RI%0CO30CO"Z (■ R+COO>OCO-<H)-"2 (■-o-25 ) (■~o-26) ([1-o-27) (■-o-28) (In -o-29) (III -o-30) (m -o-31) (IIT -o-32 ) RI (Figure CIItO()1h R, Φhunting) C11□o()OR2 R,0℃Figure 5') co□0-@-R2 RI09 coto-<R2 R1Φ\5') C11□0- □0CO1hR,Coo℃
+Cll (m -o-64) R1 ancestor R or co, o ((kiR2 R, ancestor moxibustion CH, o-@ih RI09 co, o-@;r-+>z R+0# CIItO()ORz (m -o-89) (III -o-90) (II -o-91) (m -o-92) ([1-o-93) (m -o-94) (m -o-95) (m -o-96) RIm CI!OD 0CORt RrC00+ CHtOD Rt R1 Ya x (b) C# I! Rt R, COO+ C11, osha Rz (III-p) p-13) p-14) p, -15) p-16) p-17) p-18) p-19) p-20) R1$OC1' -@-R2 R1-%oc++z% ORZ R,O bag □Bero P2-N Ya figure Doco~bo R2 R1 (Nshun0CII□■0R2 N ゝ(m -p-50) (II -p-51) (nl -p-52) 1αK) OCI+□-'D OR2 R1O+bladder OCH, (door2 R,0+■0CH2G ORt (III-q) Among the above compounds, compounds represented by formula (1-a), formula (1-b) and formula (1-c) are preferred. , formula (I-a
-1), formula (I-a-2), formula (1-a-13),
Formula (1-a-15), Formula (1-c-1), Formula (1-c-
2), compounds represented by formula (I-c-3) and formula (!c-4) are particularly preferred.

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

In this way, the SC phase has a wide temperature range and low viscosity.
C matrix liquid crystal can be obtained. By adding a chiral dopant to this, it is possible to easily achieve high-speed response in S08.
A liquid crystal composition can be obtained.

The chiral dopant used in the present invention is composed of an optically active compound, and is characterized in that it contains at least one chiral compound represented by the above general formula (A) as a constituent component.

In general formula (A), R, I and R2* are optically active groups different from each other, and at least one of R and Rt* is 01NSS, P, C/! is an optically active group containing at least one heteroatom such as
Rlth or R1'' is an optically active alkyl group having 2 to 20 carbon atoms containing at least one asymmetric carbon atom, or any one of the alkyl groups or 2 to 3 that are not adjacent to each other -C8t- each independently 10--
S--coo--oco--cos--5co--c-
↑ or may be substituted with -S-, and any one or two -CUZ- in the alkyl group are -C- (yz and Y are different from each other, HSP SC1, C11s, CF2.
Represents 0CII3 or CN. ), and any -CI+! in the alkyl group may be substituted with -CI+! -C11,-
may be substituted with -CH-Cl- or -〇miC-, and any -CH2- in the alkyl group is -CF2-
-CHa in the alkyl group is preferably an optically active alkyl group which may be substituted with -CF3.

Further, in the general formula (A), X represents the central skeleton (core) portion of the liquid crystal molecule, and X represents the general formula (C) Z.

or General formula (D) each independently represents a saturated or unsaturated 5-membered or 6-membered hydrocarbon ring, but any 1 to 2 -CH in the ring
= may be substituted with -N- or -C=, or any one or two of the rings in the ring may be substituted with -C1,-, or any one or two of the rings may be substituted with -C1,-; The central skeleton represented by 2 (
It is preferable that it is the core part.

Among the central skeletons represented by X, representative ones are listed below.

Yl represents a fluorine atom, a chlorine atom, a cyano group, a methyl group, or a methoxy group, and zl, z2 or 2. are each independently a single bond, COOOCOCHzO0CHz- is -CH2
CHzCIIx CH=CI (--C-CH1- m and n each independently represent O or 1.) (V-9
0) ■X image) -oco-<Europe (V-138) Min QC) I! Meditation's (■ ◇) oco, -0 imin (V (Hime (V-447)) Combined C00 and Hi body (■ 1 @ -0CO → (= Wahifu drop ≧ pupresent - (V-449) Combined CH2O Omi gshi\ (V tatami...shibu (V-451) [phase] (ngomi (V-501) ya Ba Shun ocope person (V-502) ya bahe CH! O pine su (V- 503) Yaji) 00CH! 赫 (V-504) 和+coo林(V-505) 和H-cocope-in (V-506) Waba-shun CH, 0peroku (V-507) 仝X-shun OCH 詝Among the optically active groups represented by R11 and R,11, representative ones are listed below.

(rV-1) CH3 fCH,-)-CH C,H.

(IV-2) CH3 -0+ CHz-)-i-CI CzHs(IV-3
) CI(3 + CHz) r-0+CH! +-CHCJs to the benzene ring or cyclo(IV-4) CB in the above central skeleton.

-0(-clI□h-0+ C8! +-Cll C
z) Central skeletons in which the Is xane ring is substituted with a fluorine atom, chlorine atom, bromine atom, methyl group, methoxy group, cyano group or nitro group can also be used.

(IV-[:1J 0-to C! H, ni H, zHs (IV-7) CH3 (-C1b-)TCll Ri CH3 0+ CH20TCHRz (TV-10) OCH3 2*゜ 10-C+ C1h +-CHR3 CH3 C8-R.

CH3 -C)lx-CI CH20R5 (rV-21) CH3 S +CH! +rCH(CHzY"CH3(rV-3
2) CH3 -OCRRa (IV-35) OCM L:Hz Utl UNs (IV
-14) C) 13 -CHCHz ORs (IV-497 to H U L;tli L;tli4(
IV-57) l OCR1CHRs (IV-53) CH2 -CH-0-R5 (IV-55) OCH2C) l Rs (IV-62) CF.

-0-C1l-R5 (IV-64) C0゜ OC1h CHCH20R5 (IV-65) C.I.

OCRCM! 0Rs (IV-66) C)13 -0 + C1h +rCH(CHz)r 0Rs(I
V-5'/J -COOCHz Ctl to tl L;zI
'ls(■-69) Cf -COOCHz CHRs (IV-70) CH3 1. -OCHz CI CHg 0CORs(IV-
71) CH3 0CHCHx OC0Rs (IV-72) CH3 1・OCHC)lz(CHz)i-0CORs(TV-73
) C) 13 1 OCHg-CH-(cHt)rOcORs(rV-80
) COOCHg CHR5 (IV-81) CN 1 OCHz CI Rs (IV-82) CN 1・CI-Rs (IV-83) CH, CN 1・ -COO-CHg -CI -R3 (IV-84) HzcN 1・ -0-CI Tomi-CH-R5 CH3 0C8! CD 0R5 (IV-76) CH3 S CHRs (IV-78) CI) Is 1・OC1h CHORb In each of the above general formulas, m represents an integer from 1 to 4, and n
represents an integer of 1 to 1O, 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. , R5 represents an alkyl group having 1 to 4 carbon atoms.

Optically active compounds containing only the optically active groups represented by formulas (IV-1) to (IV-22) are induced when added to the SC base liquid crystal to form an SC° liquid crystal composition. Even when the spontaneous polarization is very small and exhibits the S00 phase alone, most of it is only 10 nC/cm'' or less.

On the other hand, as optically active groups, formulas (IV-31) to (■-9
In the optically active compound containing the optically active group represented by 1), the spontaneous polarization induced when it is made into an SC* liquid crystal composition is large, and in cases where it shows the S01 phase alone, it is 300 n
There are some that exhibit a large value of C7cm'' or more.The chiral dopant in the present invention has a somewhat large spontaneous polarization even when added in a small amount, preferably when added at 10% to the SC base liquid crystal, it increases the upper limit of the SC'' phase. 10° of temperature
It is desirable to induce spontaneous polarization of 1.0 nC/cm" or more on the low temperature side, and RI" + as an optically active group.
At least one of Rt is (TV-31) to (I
It is desirable to contain at least one compound that is a group represented by V-91).

Preferred compounds with combinations of RIZ R1''+X are listed below.

(Vl-a-43 N4-L;ll-1 and Nzf-1Y-OtsushiUυshi11-
5 to U, -o-, -oco-, -coo- or -ocoo-
, W is a chlorine atom, a fluorine atom, or -0-CI
l.

In the above general formula, R4 and R4' each independently represent an alkyl group having 2 to 10 carbon atoms, and R3, R, and r each independently represent an alkyl group having 1 to 10 carbon atoms. represents an alkyl group,
R1 is a straight chain alkyl group having 2 to 10 carbon atoms, a branched alkyl group having 3 to 10 carbon atoms, or 4 to 1 carbon atoms
O represents an optically active alkyl group containing at least one asymmetric carbon atom, 2 represents an integer of 0 to 5, and Y represents a single bond COO- 0CO- -CH, 0 OCR, - or a single bond. As another component of the chiral dopant in the present invention, a compound in which only one side chain of a liquid crystal molecule is optically active can be used. Among these compounds,
Particularly preferable ones are listed below.

C1(.

(Vl-b-1) R"-Z'-COOC
H-R.

(■ b-2) R”-Z’ 1h -0-CH-R.

(■ R”-Z’ CH.

1 monkey OCI CIIzORs (Vl-b-9) R”-Z’ C.I.

1・ 0(j! C00Rs C0゜1・ (Vl-b-11) R"-Z' -0CO-
CIl-OR.

(■ b-5) (Vl-b-6) R”-Z’ R”-Z’ OS 1 monkey C00CHCHHz 0Rs CH.

1・ C00CHZ CH OR.

In the formula, R'' represents an alkyl group, an alkoxy group, an alkanoyloxy group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, or an alkoxyalkyl group having 1 to 20 carbon atoms, and Z', R,.

Rs, Rt, and W each have the meanings given above.

In the chiral dopant, it is desirable to use the compound represented by the -C formula (A) in an amount of 9 or more decimates, preferably 30% by weight or more, particularly preferably 50% by weight or more.

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 a proportion of 2% by weight and use it as an S00 liquid crystal composition, more preferably in a proportion of 2 to 50% by weight, and the proportion of the chiral dopant added is greater 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. In addition, increasing the amount of chiral dopant added tends to shorten the helical pitch and adversely affect the orientation, which is undesirable. On the other hand, if the amount of chiral dopant added is less than 1% by weight, spontaneous polarization occurs. becomes too small, and high-speed response cannot be expected.

The spontaneous polarization value of the SC''' liquid crystal composition is 3 to 30 nC/
It is preferable to adjust the addition ratio of the chiral dopant so that it is in the range of "c + s", and in the case of a chiral dopant exhibiting the S00 phase, it alone exhibits a spontaneous polarization of about 100 nC/c11!, or a strength equivalent to that. In the case of a chiral dopant that induces spontaneous polarization, the addition ratio of the chiral dopant is preferably in the range of 10 to 40% by weight, and 300% by weight.
In the case of a chiral dopant that exhibits strong spontaneous polarization of nC7cm" or more, the addition ratio of the chiral dopant is 2 to 25
The preferable weight percent range is the stronger the spontaneous polarization induced by the chiral dopant, the more the most desirable addition rate decreases, but for the chiral dopant made of the exemplified optically active compound, the addition rate is usually less than 1 weight percent. There isn't.

When the sc" liquid crystal composition of the present invention is cooled from an isotropic liquid state, it first undergoes a phase transition to the N9 phase, and then passes through the SA phase or directly to the S01 phase, but at that time, The temperature range showing the N'' phase is preferably in the range of 3° or more and 30° ungrooved. If the temperature range showing the N* phase is less than 3°, the phase transition to the SA phase will occur promptly when the temperature decreases.
This is not preferable because it tends to make it difficult to fully align liquid crystal molecules in the N0 phase, and the temperature range showing the N* phase is 30°C.
If it is above 0.0°, the clearing point of the S00 liquid crystal composition becomes high, which tends to have an adverse effect on workability in the step of filling the cell with liquid crystal material, etc., which is not preferable.

A chiral dopant is one that tends to expand the temperature range in which (1) it exhibits the N''' phase when added to the SC matrix liquid crystal, regardless of whether the chiral dopant itself has liquid crystallinity or not (2) N''' phase. 50 of the present invention, each having unique properties, such as those that tend to reduce the temperature range in which they exhibit a phase.
11 In order to adjust the temperature range in which the N1 phase of the liquid crystal composition is exhibited to the above preferable range, in the case of (1), an SC base liquid crystal having a narrow temperature range in which the N1 phase is exhibited, or an S
It is sufficient to use a C matrix liquid crystal, and in the case of (2), it is sufficient to use an SC matrix liquid crystal that exhibits a wide temperature range in which it exhibits the N phase.This method is applicable not only to the N0 phase but also to the SA phase and the SC'' phase. For example, if the chiral dopant expands only the SA phase of the S01' liquid crystal composition and reduces the N" phase and sc" phase, the upper limit temperature of the SC phase may be is high, the N phase temperature range is wide, and the phase sequence is SC phase → N phase → I phase, or the SA phase temperature range is narrow < SC phase → SA phase → N phase → ■ phase It is sufficient to use one having a series.

This tendency of chiral dopants can be easily determined by measuring the change in phase transition temperature of an SC liquid crystal composition obtained by adding a certain amount of chiral dopant to an SC matrix liquid crystal. Therefore, the temperature range in which each phase in the S00 liquid crystal composition exhibits, particularly the N11 phase, can be easily adjusted.

Furthermore, the helical pitch that appears in the N1 phase from the temperature at which the N* phase transitions to the SA phase or the S00 phase (the lower limit temperature of the N''' phase) to the 1° higher temperature side is 3 μm or more. Preferably, the helical pitch is 10 μm or more, and an SC9 liquid crystal composition in which the helical pitch increases divergently as the lower limit temperature of the N0 phase is approached is particularly preferred for improving alignment.

When an optically active compound represented by general formula (A) is used as a component of the chiral dopant in the present invention,
It is possible to obtain an S09 liquid crystal composition with a long helical pitch that satisfies the above conditions even with a single compound; however, if the chiral dopant concentration is within a practical range for boat fishing, does not necessarily satisfy the above conditions.

In that case, in order to adjust the helical pitch to the above-mentioned preferred range, it is necessary to add optically active compounds whose spiral directions that appear in the N1 phase are opposite to each other when added to the SC base liquid crystal to form an S00 liquid crystal composition. It is necessary to prepare chiral dopants by adding at least one type at a time.

It is well known that the helical pitch P (μm) appearing in the N'' phase of an S00 liquid crystal composition containing a plurality of optically active compounds is expressed by the concentration of each optically active substance as C1, and the helical pitch per volumetric concentration. (Here, the helical pitch is right-handed, positive,
Left-handed rotation is considered negative. ), using this, when PA at point T0 of SC "5A-N" of liquid crystal composition is set as P-, Ci can be selected so that Measurement can be performed by adding unit concentrations of each optically active compound.

In reality, T varies depending on each Ci, but it can often be estimated fairly accurately from the change in the 5A-N'' point when each optically active compound is added to the SC matrix liquid crystal at a concentration of ΣCi. If the estimated value T0 differs significantly from the To of the composition selected using the estimated value T0, the measurement may be performed again using T in place of T and t.

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

As mentioned above, for the S01 liquid crystal composition, the amount of chiral dopant added may be adjusted so that the value of Ps is in the range of 3 to 30 nC/cm, especially near room temperature.
However, when the PsO value induced by the chiral dopant is small, the amount added becomes large relative to the SC base liquid crystal, and the viscosity of the SC" liquid crystal composition increases accordingly, resulting in high-speed response. Therefore, the chiral dopant used in the present invention is preferably one that can induce Ps of 1.OnC/cm" or more when added to the SC base liquid crystal in an amount of 10% by weight. 0.5nC/ when added at 5% by weight
Particularly preferred are those capable of inducing Ps of c2 or more.

〔Example〕

The present invention will be specifically explained below with reference to examples, but the gist and scope of the present invention are not limited by these examples. In the examples, "%" means % by weight. , and the measurement of the phase transition temperature of the composition is carried out using a polarizing microscope equipped with a temperature control stage and a differential scanning calorimeter (D
SC) was used in combination.

Example 1 (Preparation of SC host liquid crystal) The following SC was prepared using a compound of formula (I-a-1) as a medium-temperature liquid crystal and a compound of formula (III-a-1) as a high-temperature liquid crystal.
A parent liquid crystal was prepared.

O matrix liquid crystal (A) (1-a-1) (III-a-1) (III-a-1) This matrix liquid crystal (A) has an SC phase at 67.5°C or lower, and a 7
Shows SA phase at 1″C or below, N phase at 80°C or below,
Its melting point was 13°C.

Q Base liquid crystal (B) (1-a-1) This base liquid crystal (B) has an SC phase at 65°C or lower, and a SC phase at 70°C.
The SA phase was shown below, and the N phase was shown below at 77.5°C, and the melting point was 7.5°C.

Example 2 (Preparation of SC host liquid crystal) A compound of formula (1-a-1) and a compound of formula (1) as a meso-temperature liquid crystal
-b-1) as a high temperature liquid crystal compound of formula (III-a-
The following SC parent liquid crystal was prepared using the compound of 1).

O matrix liquid crystal (C) (1-a-1) (1-b-1) (I[[-a ■) (When this compound is added at 10% to the SC matrix liquid crystal shown below, it appears in the N0 phase. The helical pinch that causes it is 4.7 μm at 60°C.) Compound 73 +,g, and the compound that causes the appearance of a left-handed helix, the parent liquid crystal (C) of the formula
The SA phase is shown below, and the N phase is shown below at 81.5°C.

Example 3 (Preparation of chiral dopant) When added to SC base liquid crystal to prepare S01 liquid crystal composition,
A compound that causes a right-handed helix to appear in the N1 phase is expressed by the formula (When this compound is added at 10% to the SC base liquid crystal shown below, the helical pitch that appears in the N1 phase is 11.9 μm at 60°C.) A chiral dopant with a controlled helical pitch appearing in the N1 phase was prepared by mixing 27% of the compound.

The spontaneous polarization value at 25°C of an SC8 liquid crystal composition obtained by adding 10% of this chiral dopant to the SC base liquid crystal shown below was 5.5 nC7cm2.

In addition, the SC base liquid crystal used in Example 3 was added to the SC base liquid crystal in Example 4 (preparation of chiral dopant) to form an SC° liquid crystal composition.
As a compound that causes the appearance of a right-handed helix in the N0 phase, it is a composition consisting of the formula, which causes the SC phase to appear at 57° C. or below, and 64.
It exhibited an SA phase at temperatures below 5°C and an N phase at temperatures below 69°C, and its melting point was 14°C.

(This compound was added to the SC matrix liquid crystal used in Example 3 at 10%
The helical pitch that appears in the N'' phase when added is 1.3 μm at 60°C. 10% of the compound was added to the SC matrix liquid crystal used in Example 3.
The helical pitch that appears in the N9 phase when added is 1.3 μm at 60°C. ) to prepare a chiral dopant in which the helical pitch appearing in the N'' phase was adjusted.

The spontaneous polarization value of the SC8 liquid crystal composition obtained by adding 10% of this chiral dopant to the SC base liquid crystal used in Example 3 at 25°C was 10 nC/c+w''.

A chiral dopant with an adjusted helical pitch that appears in the N* phase was prepared by mixing the above.

Example 6 (Preparation of chiral dopant) The ludopant exhibited an S01 phase at 51°C or below, an SA phase at 70.5°C or below, and an N0 phase at 71.5°C or below, and its melting point was 31″C. Ta.

Example 7 (Preparation of chiral dopant) A chiral dopant having an adjusted helical pitch and appearing in the N0 phase was prepared by mixing with the following. A chiral dopant having an adjusted helical pitch and appearing in the N0 phase was prepared by mixing with this chiral dopant. This chiral dopant is 56.5℃
The higher order chiral smectic phase is formed below with N
Each exhibited phase 0 and its melting point was 55°C.

Example 8 (Preparation of SC” liquid crystal composition) Base liquid crystal (A)
An S00 liquid crystal composition consisting of 84% of the chiral dopane h of Example 3 and 16% of the chiral dopane of Example 3 was prepared. This composition is 67.5℃
S01 phase below, SA phase below 70.5°C, 76.
Each exhibited an N9 phase below 5°C. 70.6 of this composition
The helical pitch at °C was 20 μm or more, and when it was filled into an orientation-treated cell and slowly cooled from an isotropic liquid phase, it showed extremely good orientation.

Cells subjected to orientation treatment by polyimide coating and one side rubbing were exposed to 50 H with an electric field strength of 10 VP-P/μm.
When a rectangular wave of z was applied and the electro-optical response speed was measured, it showed a high-speed response of 41 μsec at 25°C. The spontaneous polarization at this time is 14.4 nC/cm"
, the tilt angle was 30.6'', and the contrast was very good.

Example 9 (Preparation of SC “liquid crystal composition”) Base liquid crystal (B)
S consisting of 84% and 16% of the chiral dopane of Example 3)
A liquid crystal composition C'' was prepared. This composition formed an S01 phase at 65°C or lower, an SA phase at 69°C or lower, and an N phase at 73°C or lower.
*Each phase is shown.

The orientation of this composition was good, and when its electro-optical response speed was measured in the same manner as in Example 8, it showed a high-speed response of 40 μsec at 25°C.

The tilt angle at this time was 29.1'', and the contrast was very good.

Example 10 (Preparation of SC” liquid crystal composition) Base liquid crystal (A)
S consisting of 84% and 16% of the chiral dovan of Example 4)
A C1 liquid crystal composition was prepared. This composition exhibited an S00 phase at temperatures below 63°C and an N* phase at temperatures below 68°C.

When the electro-optical response speed was measured in the same manner as in Example 8, it showed a high-speed response of 50 μsec at 25°C. At this time, the spontaneous polarization was 32.1 nC/cm'' and the tilt angle was 24.7'.

Example 11 (Preparation of SC" liquid crystal composition) Base liquid crystal (, ~
) and 20% of the chiral dopant of Example 5 was prepared. This composition is 66.5℃
SC1 phase at 70℃, SA phase at 75.5℃ or less
℃ or lower, each exhibited an N'' phase.

When the electro-optical response speed was measured in the same manner as in Example 8, it showed a high-speed response of 37 μsec at 25°C. Note that the orientation was very good. At this time, the tilt angle is 30.3@, and the spontaneous polarization is 17.4 nC7cm"
The contrast was very good.

Example 12 (Preparation of SC''' liquid crystal composition) Base liquid crystal (C
) and 30% of the chiral dopant of Example 6 was prepared. This composition exhibited an S01 phase at 60°C or below, an SA phase at 71°C or below, and an N1 phase at 76°C or below.

When the electro-optical response speed was measured in the same manner as in Example 8, it showed a high-speed response of 117 μsec at 25°C. Note that both orientation and contrast were very good. The tilt angle at this time is 23.6', and the spontaneous polarization is 6
．． 9nC/c+i''.

Example 13 (Preparation of SC” liquid crystal composition) Base liquid crystal (C)
S consisting of 80% and 20% of the chiral dopant of Example 7
00 liquid crystal composition was prepared. This composition exhibited an SC'' phase at 60.5°C or lower, an SA phase at 61°C or lower, and an N'' phase at 76°C or lower.

When the electro-optical response speed was measured in the same manner as in Example 8, it showed a high-speed response of 12 μsec at 25°C.

Example 14 (Preparation of SC” liquid crystal composition) Base liquid crystal (C)
S consisting of 80% and 20% of the chiral dopane of Example 3)
A C0 liquid crystal composition was prepared. This composition exhibited an SC" phase at 67.5°C or lower, an SA phase at 71°C or lower, and an N" phase at 76°C or lower.

When the electro-optical response speed was measured in the same manner as in Example 8, it showed a high-speed response of 35 μsec at 25° C., and both orientation and contrast were good.

〔Effect of the invention〕

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

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

Agent: Patent Attorney Katsutoshi Takahashi

Claims (1)

[Claims] 1. (1) Smectic C having a two-ring structure, which is optically inactive and may be monotropic in any temperature range of 1 degree or more at 10 degrees Celsius or higher. (b) a liquid crystal compound exhibiting a smectic C phase with a three-ring structure having a cyclohexyl ring, or (c) the above (a)
or a homologue of the compound of (b) that differs only in the number of carbon atoms in the alkyl chain or in the structure;
2) Optically inactive, the upper limit temperature of the smectic C phase is 90°C or higher, and may be monotropic at least in a temperature range of 5°C or higher; (a) consisting of a 3-ring or more ring structure; , a liquid crystal compound exhibiting a smectic C phase, or (b) a high temperature liquid crystal exhibiting a smectic C phase consisting of a homologue of the compound that differs only in the number of carbon atoms or structure of the alkyl chain. (3) a ferroelectric liquid crystal composition comprising the addition of a chiral dopant comprising an optically active compound,
The optically active compound has the general formula (A)R_1^*-X-R_2
^* (In the formula, X represents the central skeleton (core) part of the liquid crystal molecule, and R_1^* and R_2^* are different optically active groups in which at least one group contains at least one hetero atom. A ferroelectric liquid crystal composition exhibiting a chiral smectic C phase over a wide temperature range including room temperature, characterized by being a compound represented by the following formula: 2. X is a general formula (B) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ General formula (C) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ Or general formula (D) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, there are ▲mathematical formulas, chemical formulas, tables, etc.▼, ▲mathematical formulas,
There are chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ and ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ are each independently saturated or unsaturated 5-membered or 6-membered ring hydrocarbons Although it represents a ring, any 1 or 2 -CH= in the ring may be substituted with -N= or ▲There are numerical formulas, chemical formulas, tables, etc.▼, and any 1 or 2 -CH= in the ring ~2 -CH_2- are
-O-, -S-, -NH-, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ may be substituted, and any one to The two ▲There are mathematical formulas, chemical formulas, tables, etc.▼ may be replaced with ▲There are mathematical formulas, chemical formulas, tables, etc.▼. Y_1 represents a fluorine atom, a chlorine atom, a cyano group, a methyl group, or a methoxy group, and Z_1, Z_2 or Z_3 each independently represent a single bond,
-COO-, -OCO-, -CH_2O-, -OCH_
2-, -CH_2CH_2-, -C≡C-, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas There are tables, etc. ▼ or -CH=CH-
represents -CH_2-, -CH_2CH_2
-, -CH=CH-, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, -S-, or -O- Representation,
m and n each independently represent 0 or 1. 2. The ferroelectric liquid crystal composition according to claim 1, wherein the central skeleton (core) portion is represented by: ). 3. R_1^* and R_2^* are optically active alkyl groups having 2 to 20 carbon atoms containing at least one asymmetric carbon atom, or any one of the alkyl groups or each other 2 to 3 non-adjacent -CH_2- each independently represent -O-, -S-, -COO-, -OCO-, -CO
S-, -SCO-, ▲Mathematical formulas, chemical formulas, tables, etc.▼
or ▲There are mathematical formulas, chemical formulas, tables, etc. ▼ may be substituted, and any 1 to 2 -CH_ in the alkyl group
2- has ▲mathematical formulas, chemical formulas, tables, etc.▼(Y_2 and Y_3 are different from each other, H, F, Cl, CH_3, CF
_3, OCH_3 or CN. ), and any -CH_2-CH_ in the alkyl group may be substituted with
2- may be substituted with -CH=CH- or -C≡C-, and any -CH_2- in the alkyl group is -CF
_2- may be substituted, and -C in the alkyl group
3. The ferroelectric liquid crystal composition according to claim 1, wherein H_3 is an optically active alkyl group optionally substituted with -CF_3. 4. When cooling from an isotropic liquid state, 3 degrees or more
In the temperature range from the temperature at which the chiral nematic phase undergoes a phase transition from the chiral nematic phase to a phase on the lower temperature side through a chiral nematic phase having a temperature range of less than 0 degrees to the temperature 1 degree higher than the phase transition temperature, the chiral nematic 4. The ferroelectric liquid crystal composition according to claim 1, wherein the phase has a helical pitch of 3 μm or more. 5. When adding 10% by weight to a liquid crystal composition exhibiting a smectic C phase to produce a ferroelectric liquid crystal composition exhibiting a chiral smectic C phase, 1. Claim 1: A chiral dopant that induces spontaneous polarization of 0 nC/cm^2 or more is used.
, 2, 3 or 4. The ferroelectric liquid crystal composition according to . 6. The ferroelectric liquid crystal composition according to claim 1, 2, 3, 4, or 5, which undergoes a phase transition to a chiral nematic phase, then to a smectic A phase, and then to a chiral smectic C phase upon cooling from an isotropic liquid state. .