JPH02229885A - Ferroelectric liquid crystal composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition giving a liquid crystal display element having excellent response and memory property by adding a specific optically active compound as a chiral dopant to an optically inactive liquid crystal composition exhibiting smectic C phase. CONSTITUTION:The objective composition is produced by adding (A) a compound of formula (R<a> and R<b> are 2-10C alkyl, etc.; Y<a> and Y<b> are F, CN, etc.; m is 0 or 1; l is 0-10) as a chiral dopant to (B) an optically inactive composition containing (i) a bicyclic liquid crystal compound (homologue) exhibiting smectic C phase and (ii) a tricyclic liquid crystal compound (homologue) having cyclohexyl ring and exhibiting smectic C phase and (C) an optically inactive liquid crystal composition exhibiting smectic C phase at the upper limit temperature of >=90 deg.C and containing (iii) a >=3-cyclic liquid crystal compound exhibiting smectic C phase and (iv) a homologue of the component (ii) exhibiting smectic C phase. The liquid crystal composition B may be monotropic at >=10 deg.C.

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 to be used in optical shutters, printer heads, flat-screen televisions, etc., and research and development is currently being conducted in various fields to put it into practical use.

The liquid crystal phase of the ferroelectric liquid crystal belongs to the tilted chiral smectic phase, and among these, the one that is practically desirable is the chiral smectic C (hereinafter abbreviated as S00) phase, which has the lowest viscosity. It is called.

[Problems to be Solved by the Invention] Liquid crystal compounds exhibiting the S01 phase (hereinafter referred to as SC "compounds") have been studied so far, and a large number of compounds have already been synthesized. SC of
The 0 compound alone meets the following conditions for use as an optical switching element for ferroelectric liquid crystal displays: (a) exhibiting ferroelectricity in a wide temperature range including room temperature; Having a series (c) Omitted.

(2) (E) (F) In particular, the chiral nematic (hereinafter abbreviated as "N") phase must exhibit a long helical pitch. It must have an appropriate tilt angle. It must have low viscosity. It must have a large value of spontaneous polarization above a certain level. In addition, there is no known product that satisfies all of the following: (G) (Ex) and (C) result in good orientation, and (J) (E) and (E) result in high responsiveness. Therefore, at present, liquid crystal compositions exhibiting the S04 phase (hereinafter referred to as sc
The reality is that liquid crystal compositions (referred to as "liquid crystal compositions") are used for research purposes.

In order to obtain good distribution properties, for example, JP-A-61-1
As shown in Japanese Patent No. 53623, etc., in liquid crystals 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 temperature range between the S00 phase and the N'' phase, the orientation will be better, and in order to increase the helical pitch, a left-handed helix will be generated 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 alignment, they do not necessarily provide high-speed response. is, for example, a parent liquid crystal exhibiting a low viscosity smectic CC (abbreviated as SC) phase, as shown in the special lecture at the 12th Liquid Crystal Conference (P. 98 of the conference proceedings). The composition (hereinafter referred to as SC matrix liquid crystal) has spontaneous polarization (hereinafter abbreviated as Ps).
) A method of adding a compound with a large SC* 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. 62-583.

RO +C00 +OR' (R and R' represent achiral alkyl groups.) 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. It is in.

[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 as shown below, by adding a compound itself or It is a composition in which the homologs are limited to those exhibiting the SC phase, or in addition, a liquid crystal compound that exhibits a strong dipole (polarization) in the direction perpendicular to the long axis of the molecule is added, and the homolog is the composition that exhibits the SC phase. There is a problem in that if the temperature range is kept wide, the viscosity increases, and if the viscosity is kept low, the temperature range of the SC phase becomes narrow.

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

...(A) Provides an SC liquid composition exhibiting an SC phase in a wide temperature range including room temperature, which is obtained by adding a chiral dopant containing at least one optically active compound represented by (A) as a constituent component. .

In the general formula (A), R" represents an alkyl group having 2 to 10 carbon atoms, Rb represents an alkyl group, alkoxyl group, or alkanoyloxy group having 1 to 10 carbon atoms, and Y1 represents a fluorine atom or a cyano group. , yb represents a hydrogen atom, a fluorine atom, or a cyan group, m represents O or 1, l represents an integer from O to 10, c1 and c
O each independently represents an asymmetric carbon atom with (R) configuration or (S) configuration, Z1 and Z2 each independently represent a single bond,
Coo OCO C}IzO OC
Hg-, CIhCth c=c cos- or -SCO-, Z3 is a single bond, -coo--
aco--o-Y1 and Yt represent a hydrogen atom or a fluorine atom.

Particularly preferably, in general formula (A), Zl and Z″
are each independently a single bond, -COO1 or -OCO1, and Z3 is a single bond, -coo- -oco- The SC base liquid crystal used in the present invention has the following properties: (stomach)! (Isotropic liquid) A liquid that has a phase sequence of phase → N phase → SA phase → SC phase (1) A liquid that has a phase sequence of ■ phase → SA phase → SC phase (c) I phase → N phase → SC phase or (2) a phase series of I phase → SC phase, but the selection of (a) to (2) depends on the chiral dopant used at the same time. different. The most commonly used method is (a), which shows the nematic property of the chiral dopant (when added to the SC matrix liquid crystal, N
If there is a strong tendency to widen the temperature range of the phase and narrow the temperature range of the SA phase, the smectic A property of the chiral dopant (when added to the SC base liquid crystal)
If there is a strong tendency to widen the temperature range of the A phase and narrow the temperature range of the N1 phase, select (c), or if the SC property is weak and the temperature range of the N1 and SA phases tends to widen. It is most appropriate to use (2). What is important is the phase series in the case of a sc" liquid crystal composition, and in one sense, the phase series I→N*→SA-4SC" is advantageous in terms of orientation. On the other hand, the phase series ■→N0→S00 may also show better orientation depending on the orientation control method.
Also, since it is easy to obtain a large tilt angle, it is suitable for guest-host systems.

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

The medium-temperature range host liquid crystal referred to here means that the liquid crystal compound constituting it is optically inactive and has a two- or three-ring structure, and in the case of a three-ring structure, at least one ring is a cyclohexyl ring. and consists of a compound exhibiting an SC phase or a homologue that differs only in the number of carbon atoms and shape of its alkyl chain, and at least one compound among the homologs exhibits an SC phase at any temperature of 1°C or higher at 10°C or higher. It is a compound that exhibits an SC phase that may be monotropic in the temperature range of . However, in the case of a three-ring structure, the upper limit temperature of the SC phase is less than 90°C, and the liquid crystal exhibits an SC phase that may be monotropic at any temperature range of 10°C or more between 10°C and 80°C. Oh moat.

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

(1-a) (1-a-7) R. Olga OR! F (I -a-9) R1{to\OR+ N-N (I -a-39) R,COO{(叉｛cooRz F (I-b) (1 -c) (1 -b-31 ) (I-b-32) (1-b-33) (1-b-34) (1-b-35) (1-b-36) (1-b-37) (I-b-38) RIOCO+coo{cbookORyo R.ocoo{filter coo{(defense R2 R,OCOO dependent defense C00{defense R2 RIOCOO+C00+ORt F RIOCOOcombination coo{ode OR, F R.OCOO dependent tcoo{defense OR, R10 {Bocoo Association OCOOR . C00shaoRz ``(I-c-27) RICOOeCOOshaOR.R (■d) (1-e) (1-e-1) (1-e-2) P SC matrix 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 using a low-viscosity medium-temperature host liquid crystal.The high-temperature liquid crystal mentioned here is
A non-optically active compound that mainly consists of three or more rings and exhibits an SC phase, its homolog, or a composition consisting of these; The upper limit temperature is 90°C or higher,
and S in a temperature range of at least 5 degrees or more.
It shows a C phase, and its homologs may have an upper temperature limit of less than 90°C, a temperature range of less than 5°C, or a SC phase that may be monotropic. Yes, as a composition, the upper limit temperature of the SC phase is 9
It exhibits an SC phase in a temperature range of 0° C. or higher and a temperature width 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, Rl, R
Each t independently represents an alkyl group having 1 to 18 carbon atoms.

(■ a) F (III-b) (■ C) (■ d) (■ d-5) R,0{K Dark sequence R2 F (Ill-d-12) R. OΦIrisawaorOR, (■ e) (■ f) (III-f Rl《X moxibustion COO{}OCOR2 (III-f47) R,0℃XφCOOG OCORx F (I [[-f-19) RICOO {Inscription COO℃ト(II[-f-20) n, coo＜H〆■coo(}oat (■ f-21) R, {〆Φcoogu}) COORt F (■ g) (III -h) (I[ [-i) (ILj) (■ k) (m-j-8) R.O @coo@OCR, {feather OR!ρ (III-j-10) RIOGCOO℃>oclit+Rt p (m-j-12) R+ 《》COO■oCH!{}Rt (DI-j43) R -@-OCO@-CI'0-@-R- (■ j-14) R,0 《》oco(gshiCH,O{} Rt(III-
f) Compounds having the following 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.

/ (III-+w-17) (III-m-18) (■One piece-19) (III-sr-20) (m -n+-21) (■One request-22) (m-w-23) ( III-m-24) R, or X-coo? OCOR2 R, coo<H corner ki C00 {chin 2 R, <H hunting 5> coo-@-R. R,《h}COO-@-OR2 R,Om C00-@-R- R,0《X》COO-@7-OR2 R,0 and 4COO{}OCORz RrCOo岱-@- C00-@-R- ([[ -m-
49) (I[I-m-50) (In -m-51) (■-m-52) (I[I-a+-53) (III -a+-54) (I[[-m-55) (m -m-56) R, {鑞■-coo-《ii2 R,-＜原或C00{}ORz R, ℃lips C00{ii2 R10{pa moxibustion coo{}ORz R, -C BA■C00{}OCORz R, coo{Moxibustion C00{Ch2 R+ΦBa Moxibustion coo{}R, R, distorted moxibustion coo{}ORZ (m -a-85) (III -m-86) (m - ta-81> (m -m-88) R, ecoo-@-R. 1?coo-@-oR. R10eCOO.-@-R- R+OΦ separate Dcoo-@-oa- (III-n-5) (I!I-n-6) (Hl -n-7) (In-n-8) (n[-n-9) (II-n-10) (III -n-11) (II-n- 12) R1{}yuto OCO+ OCORz R,Coo{shi■'!-OCO{i2 R,-4 or p>OCO{ci2 R{defense 10CO{feather OR. R10{filtration 10CO{i2 RIO -4Na10CO{}OR2 R1-@S10CO{}OCOR2 R.C00-@-/X10CO{}R, (nl-n-3
7) (II-n-38) (n[-n-39) (III -n-40) (lli -n-41) (■-n-42) (III-n-43) (m -n- 44) R, Yube (9) OCO {Child 2 N {■{Gun Rl ○ OCO OR ZN R, O ■ Country DOCO {(Child 2 N R, Q and Figure IDOcO-@-OR. N R+ and 4oco{ (Feather ocoRz N {゛■} R+COO Q OCOeRz N R1 ◇-@-OCO-@-R- N R [phase] {} R, I OCO OR! (I[[-
o) (In -n-101) (11-n-102) Rl% OCO -@”- OCORzRICOO$
OCO-@-Rz (II[ -o-25) (III-o-26) ( m -o-27) (III-o-28) ( m -o-29) (III -o-30) (m -o-31) (III-o-32)? 1e'DCI'0 {re. RII CII■O{iR2 R,O and 4CIttO{}Rz R. Oe CIITO 姑OR, R. Ya$CHzO{}OCORz RICOOya\p CH-0-@-R-R,《X\CH
■08R2 R1'C\:z CH-0-@-OR-([-o-57
) (III-o-58) (III-o-59) (m-o-60) (m-o-61) (nI-o-62) (m-o-63) (I[I-o- 64)? Ba moxibustion {feather R, O CH■O
Rz↓X or combination RIO CR20 0R
2 bar moxibustion {} R, CH20 0CO
RZcoo eruption OR
zR1 Sobe(ha) CI12-}R! R+progenitor moxibustion Ct{zO{}ORz R. 0 ancestor moxibustion CHzO{}Rz R. Osobe Moxibustion CH! 0{}OR* (II[-o-89) (III-o-90) (m-o-91) (m-o-92) (m-o-93) (III-o-94) (III -o-95) (I[[ -o-96) R. <:=ζ former====ear=huge
OCOrshi2R+COO% CII! O@Rt RIeCH20 building”- Rl l CHIO-@- ORZ R, OnCH-'-@- ' R.O% CH,0+ ORg RI$ co.o-@.- OCORzR,COO e
Cl{zOe Rt (II[-p) (II[-p-13) (I[[ -p-14) (III-p-15) (m -p-16) (II -p-17) (III -p-18) (III-p-19) (III-p-20) ? , heart+OC1{-{(wing R2 N R, bag H stubborn oCH! G ORZ N R.O and H are OCII ocn-G OCORzN R+C00WOCH!D RZ N R1(3)+OCH=-@-R- N R,ya<ocotΦdoorR2 N (■ (■ p-50) p-51) To◎-@-OCR-@- OR- R.0 and 8 moxibustion cu, G Rt (■ q) (■ q - 65) ( m -q-66)?
COO Soba Moxibustion Cll ■ CO Interpretation DR = (I[l -q (■ q-98) C I[I -q-99) (I[I -q-100) (■ q-101) (■ ~ q -102) Hat q-103) (I!I-q-104) ? I$ CI{2CI12Q Rz Rl % CHzCtlz+ ORZ R, down◇-GCII opening meeting R2 R, oΦ+CII■cutsha OR2 R, '15 figure DCHzCHzsha ocoRzR+COOG
GCHzCHzCR- Rl l CHZCH2+Rg Rl℃double Dcu. Cu. -0,}- Among compounds with ORz or higher, compounds represented by formula (I-a) and formula (1-b) are preferable as medium-temperature host liquid crystals, and compounds represented by formula (I-
a-IL formula (1-a2), formula (I-a-5), formula (1-
a-41), formula (1-a-42) and formula (I-b-1)
Particularly preferred are compounds represented by: In addition, as high-temperature liquid crystals, formula (III-a), formula (I[I-b), and formula (
Compounds of formula (III-c) are preferred;
I-a-1), formula (III-a-2), formula (III
-a-13), formula (II[-b-1), formula (I[
Particularly preferred are compounds represented by [-c-1) and formula (II[-c-3).

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

In this way, the SC phase has a wide temperature range and low viscosity.
C matrix liquid crystal can be obtained. By adding a chiral dopant to this, it is possible to easily achieve high-speed response in S01.
A liquid crystal composition can be obtained.

The chiral dopant used in the present invention includes (1) S
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 properties at all.
In order to prevent the tendency for the liquid crystallinity of the SC1 liquid composition obtained by adding it to the base liquid crystal to decrease, it is preferable to use a compound having a skeleton similar to that of a liquid crystal.

Among the various physical properties that a 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 the magnitude of spontaneous polarization is particularly important in terms of responsiveness. be.

As mentioned above, the present invention characteristically contains an optically active compound represented by the general formula (A) as a constituent of the chiral dopant.

Although it is known that the compound represented by the general formula (A) of the present invention can exhibit excitation polarization, it is possible to exhibit even more excellent properties if another optically active group is used as the other side chain. It's Chino.

The advantages of using the compound represented by the general formula (A) as a component of a chiral dopant include the following.

(1) It can exhibit stronger spontaneous polarization than compounds with chiral groups on only one side. That is, the above compound and a chiral group on only one side of the compound represented by the following general formula (B)... (B) Z2, z3, m and R1 have the same meanings as in formula (A)) Adding the compounds having each to the SC base liquid crystal,
When calculating the spontaneous polarization as an extrapolated value, under the same conditions, the compound of general formula (A) has a value of 10 to 30 nC/cm" or more, which is higher than the simple sum of the spontaneous polarization values due to the chiral groups on both sides. It can be seen that the values are also large.

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

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

As mentioned above, in order to obtain good dispersion, it is necessary to
It is important that the helical pitch in the phase or S00 phase is long. It is only necessary that the helical pitch of the chiral dopant as a whole is adjusted, and it is not necessary for individual compounds to do so, 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. However, all the compounds of general formula (B) had short helical pitches. By selecting an optically active group of the general formula (A) whose direction of helical pitch is opposite to that of R"-CH-0, it is possible to lengthen the helical pitch. Conversely, the helical pitch can be adjusted. When the main purpose is to add CH3, the shorter the helical pitch, the more the amount of CH3 to be added can be suppressed. , 20 to 30 nC/cm" or less,
The orientation is rarely necessary, but in more cases it is desirable to align the orientations so that they do not cancel each other out.

Specifically, as a compound represented by general formula (A),
The following compounds may be mentioned.

In the above, C is a crystalline phase, N'' is a chiral nematic phase, and SA
represents a smectic eight phase, and ■ represents an isotropic liquid phase. For those whose transition temperature is not stated, a liquid crystal phase is observed during rapid cooling, but due to crystallization, the transition temperature could not be measured. ~Formula (I
Although the presence of a liquid crystal phase could be confirmed in the compound represented by V-8), it was difficult to even identify it.

In the present invention, as a component of the chiral dopant,
In addition to the compound of general formula (A), ordinary optically active liquid crystal compounds can also be used. These optically active compounds include compounds that have the optically active groups listed below as one or both side chains in a general liquid crystal central skeleton, or compounds that have an asymmetric carbon in the central linking group or ring structure. can be mentioned. (However, the compound of formula (A) is excluded.) Typical optically active groups that have been used so far are as follows.

(IV-1) (IV-2) (IV-3) (IV-4) CFI3 ÷ C I1 2 +r C H C. H, CHff 1°C Hz +-CI CzllsCH3 + CHth-0 +CHz-+TCH CJsCH
3 10+CH2h-0÷CH2÷-CHCzHs(IV-
7) CL 1・÷C}+! +T-CH R3 (IV-8) CH3 -O + CHz-+T-CH R:+(■ CH3 -CH-R4 (IV-13) CH. -CHz-CH Clh ORs (TV-14) C113 -Ct{ CHz ORs ?H. S -{- CH Z -h- Cll (cIl ■ Chircll3 (IV-32) (IV-43) (TV-48) CH3 -O-CIl-R4 O Cl!, 11 ・QC Cll ORs c++:+ 0. II -CB-C-0 R, CH, 1CH-0-RS (IV-55) ?0-CIl■-Cll-RS (IV-57) Cl 1・O CH! CH Rs (IV-69) Cl -COOC}Iz CH Rs (rV-70) CI!3 J Cl{z C}I CHz OCORs (
IV-71) Cth O CH CH2 0 CORsCH3 (IV-73) CH3 0 CHZ-CH-{CHzh OCOR5 (■ O CF. l1 -C-0-Cll R5 (IV-62) CF. 1. -O C} I Rs (IV-64) CHI O CHz CH CHz ORs (IV-6
5) C11, -O-CH CH, -OR, (IV-66) CH3 -O {- C}l. ÷, CI{CHz}rORs(I
V-75) 10CH3 CTo CH ORs (IV-76) CH3 -S-CH-R5 (IV-78) C2H, O Cllz CH ORa (IV-81) 10CN Cllz CH Rs (IV-82) CH -R, (rV-83) 1000 CI,CN CH z (Jl --- R s (IV-84) ?IIzCN -O-CIl■100-RS In each of the above general formulas, m is 1 to 4 represents an integer of n
represents an integer of 1 to 10, R represents an alkyl group having 3 to 8 carbon atoms, R4 represents an alkyl group having 2 to 10 carbon atoms, and R represents an alkyl group having 1 to 10 carbon atoms. , and R represents an alkyl group having 1 to 4 carbon atoms.

As optically active groups, formulas (IV-1) to (IV-22
) When an optically active compound containing only an optically active group represented by
Even if a phase is shown, most of them are only below 10 nC/c.

On the other hand, as optically active groups, formulas (IV-31) to (■-9
When an optically active compound containing an optically active group represented by 1) is added to an SC base liquid crystal to form an S01 liquid crystal composition, the spontaneous polarization induced is thick. Some exhibit large values of 300 nC/cm" or more.

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

(V-66) 104} (V-90) 10 {■・・・−＜Europe (V-138) ◇｝OCR, meditation (V-162) Minutes OCHz-○be now (V-186) ω Be clear OCR! R-note (V-210) {}na}coco. {} (V Every evening OCHz {} (V-260) Kuimai}...{} (V-446) ℃ extra included (V Combined C00《→included (V-448) Combined OCO《→enter (■ ■co, oh included (V-450) ? OC11 ■ {Sagiiri (V-451) [Phase] {X included (V {TOOO Matsuiri (V-501) Sobe Toshioco Yaro (V Ya R Shun CH. 0~\ (V-503) ? Pa}OOCH■Hayashi (V-504) lRdcoobayashi (V-505) )-@-oco Itoto (V-506) Nyo X Shun CH, 0 Akira (V-507) Wax Shun OCH2 Akira It is.

Among the above, the basic skeletons represented by formulas (V-1) to (V-274) and those in which the benzene ring thereof is substituted with a fluorine atom are preferred;
3), formula (V-7) to formula (V-9), formula (V-17),
The basic skeletons represented by (V-18), (V-21), formula (V-22), or formulas (V-25) to (V-274) are particularly preferred.

Fluorine atom, chlorine atom,
Each basic skeleton substituted with a bromine atom, methyl group, methoxy group, cyano group or nitro group can also be used. In particular, basic skeletons substituted with fluorine atoms are often preferred.

In addition, among the above basic skeletons, those with left-right asymmetrical ones can be used in the same way even if the left-right sides are reversed.The chiral dopants listed in L are added to the SC matrix liquid crystal at a ratio of 1 to 60%. It is suitable to use it as an SC" liquid crystal composition, but it is more preferable to add it in a proportion of 2 to 50% by weight.
If the amount exceeds % 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 a negative impact on high-speed response. This is not desirable as it tends to be Furthermore, an increase in the amount of chiral dopant added tends to shorten the helical pitch, thereby adversely affecting the conformation properties, 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. It is preferable to adjust the addition ratio of the chiral dopant so that the spontaneous polarization value of the S01 liquid crystal composition is in the range of 3 to 30 nC/cm.
In the case of a chiral dopant that alone exhibits spontaneous polarization of about 100 nC/CIIIz or induces spontaneous polarization of an equivalent strength, the addition ratio of the chiral dopant is 10
-40% by weight is preferred, 300 nC/c
In the case of a chiral dopant exhibiting strong spontaneous scratching of m2 or more, the addition ratio of the chiral dopant is preferably in the range of 2 to 25% by weight. As the spontaneous polarization induced by the chiral dopant becomes stronger, the most desirable addition ratio decreases, but in the case of the chiral dopant made of the exemplified optically active compound, the addition ratio does not fall below 1%.

When the SC* liquid crystal composition of the present invention is cooled from an isotropic liquid state, it is desirable that the composition first undergoes a phase transition to the N* phase, and then undergoes a phase transition through the SA phase or directly to the SC0 phase. At that time, the temperature range showing the N1 phase is 3° or more and 30°
A range of ゜not dripped is preferable. The temperature range showing the N1 phase is 3
If it is less than 100°, it is not preferable because a phase transition occurs quickly to the SA phase when the temperature is lowered, making it difficult to sufficiently align liquid crystal molecules in the N1 phase. In addition, if the temperature range showing the N0 phase is 30° or higher, the clearing point of the S04 liquid crystal composition becomes high, which tends to have a negative effect on workability in the process of filling the cell with liquid crystal material, which is not preferable. .

Regardless of whether or not the chyranoredorbant itself has liquid crystallinity, when added to the SC base liquid crystal, the chyranoredorbant tends to (1) expand the temperature range in which it exhibits the N'' phase, or (2) ) Each has its own unique properties, such as those that tend to reduce the temperature range in which the N'' phase is exhibited. SC of the present invention
*In order to adjust the temperature range in which the N* phase of the liquid crystal composition is exhibited to the above preferable range, in the case of (1), the SC base liquid crystal has a narrow temperature range in which the N phase is exhibited, or the SC base liquid crystal does not exhibit the N phase. S
A C 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 N11 phase but also to the SA phase and the S01 phase. For example, when a chiral dopant expands only the SA phase of the SCI liquid crystal composition and reduces the N9 phase and SC1 phase, as an SC base liquid crystal, the upper limit temperature of the SC phase is high and the temperature range of the N phase is It is sufficient to use one having a wide phase sequence of SC phase→N phase→I phase, or one having a narrow SA phase temperature range<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 S04 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 S00 liquid crystal composition exhibits the N'' phase can be easily adjusted.

Furthermore, it is preferable that the helical pitch appearing in the N* phase from the temperature at which the N* phase transitions to the SA phase or the S01 phase (the lower limit temperature of the N'' phase) to the 1° higher temperature side is 3 μm or more, S01 liquid crystal compositions in which the helical pitch is 10 μm or more and the helical pitch increases divergently as the lower limit temperature of the N9 phase is approached are 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,
Although it is possible to obtain an SC4 liquid composition with a long helical pitch that satisfies the above conditions even with a single compound, generally speaking, if the concentration of the chiral dopant is within a practical range, the helical pitch does not necessarily satisfy the above conditions.

In that case, in order to adjust the helical pitch to the above-mentioned preferred range, it is necessary to add optically active compounds whose helical directions that appear in the N9 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.

The helical pitch P (μm) appearing in the N0 phase of an S00 liquid crystal composition containing multiple optically active compounds is determined by the concentration of each optically active substance being Ci, and the pitch of the helix per unit concentration being Pi.
(μm) (Here, the right-handed spiral pitch is positive, and the left-handed spiral pitch is negative.) Using this, sc"
If SA-N of the liquid crystal composition "pi at point T0 is P," then Ci should be selected so that. Here, Pi can be measured by adding each optically active compound at a unit concentration to the SC liquid crystal having an N phase.

In reality, T0 changes depending on each Ci, but it can often be inferred fairly accurately from changes in the SA-N'' point when each optically active compound is added to the SC matrix liquid crystal at a concentration of ΣCi, and If the value 1-[% 01 and T0 of the composition selected using it are significantly different, T
．． You can use T0 instead of / and measure again. The chiral dopant used in the present invention is required to induce a certain level of spontaneous polarization (hereinafter abbreviated as P) by adding it to a certain amount of SC host liquid crystal.

As mentioned above, in the SC* liquid crystal composition, the amount of chiral dopant to be added may be adjusted so that the value of P is in the range of 3 to 30 nC/cn+'' especially near room temperature.

However, chiral dopant-induced P. If the value of is small, the amount added will be large relative to the SC base liquid crystal, and accordingly the viscosity of the S04 liquid crystal composition will become thicker, and as a result, there is a tendency that high-speed response cannot be obtained. I don't like it because it is. Therefore, when the chiral dopant used in the present invention is added in an amount of 10% to the SC base liquid crystal, 1. It is preferable to use a material that can induce P of 0 nC/am” or more, and when adding 5% by weight, 0.5nC/am” or more is preferable.
Particularly preferred are those capable of inducing P3 of C/cm'' or higher.

〔Example〕

The present invention will be specifically explained below with reference to Examples, but the gist and scope of the present invention are not limited by these Examples. In addition, in the examples, "%" is % by weight.
represents. The phase transition temperature of the composition can also be measured using a polarizing microscope equipped with a temperature control stage and a differential scanning calorimeter (DS).
C) was used in combination. Example 1 A chiral dopant consisting of 24% and 76% of the compound of formula (VI-1) was prepared.

Next, as a medium temperature range liquid crystal, from the compound represented by the general formula (I-a-1), 28% 24%, and as a high temperature liquid crystal, from the compound represented by the general formula (I[I-a-1), An SC matrix liquid crystal consisting of F was prepared.

This SC matrix liquid crystal exhibits an SC phase at temperatures below 68.5°C.
．． It exhibited an SA phase at temperatures below 5°C, an N phase at temperatures below 83.5°C, and an isotropic liquid (1) phase at temperatures above these. Its melting point was 13.0°C.

88% of this SC matrix liquid crystal and 12% of the above chiral dopant
When an SC1 liquid composition was prepared, it showed an S011 phase at 64°C or lower, an SA phase at 68°C or lower, and an N'' phase at 75°C or lower.The melting point was not clear.

This S00 liquid crystal composition was filled into a glass cell with a thickness of about 2 μm that had been subjected to an alignment treatment (polyimide coating/rubbing treatment), and when it was slowly cooled from the (2) phase, it exhibited extremely good alignment. In this cell, the electric field strength toVr-r/μm is 50
When we measured the electro-optical response speed by applying a square wave of 611 to
t = done.

The spontaneous polarization at this time was 21 nC/cm'', and the contrast was good.

Example 2 A chiral dopant consisting of 50% and 50% of the compound of formula (Vl-3) was prepared.

Next, an S00 liquid crystal composition consisting of 16% of this chiral dopant and 84% of the SC matrix liquid crystal used in Example 1 was prepared. This S00 liquid crystal composition exhibits an S08 phase at temperatures below 63°C and an N'' phase at temperatures below 68°C, and exhibits an I phase at temperatures above 63°C.
It became a phase.

When the electro-optical response speed was measured in the same manner as in Example 1, a high-speed response of 50 μsec at 25° C. was confirmed.

〔Effect of the invention〕

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

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

Claims (1)

[Claims] 1. (1) Smectic C having a two-ring structure, which is optically inactive and may be monotropic in any temperature range of 1 degree or more at 10 degrees Celsius or higher. (b) a liquid crystal compound exhibiting a smectic C phase with a three-ring structure having a cyclohexyl ring, or (c) the above (a)
or a homologue of the compound of (b) that differs only in the number of carbon atoms in the alkyl chain or in the structure;
2) Optically inactive, the upper limit temperature of the smectic C phase is 90°C or higher, and may be monotropic at least in a temperature range of 5°C or higher; (a) consisting of a 3-ring or more ring structure; , a liquid crystal compound exhibiting a smectic C phase, or (b) a high temperature liquid crystal exhibiting a smectic C phase consisting of a homologue of the compound that differs only in the number of carbon atoms or structure of the alkyl chain. (3) A ferroelectric liquid crystal composition with the addition of a chiral dopant, where the chiral dopant has the general formula (A) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, R^a is a carbon atom] R^b represents an alkyl group having 2 to 10 carbon atoms, an alkyl group having 2 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, or an alkanoyloxy group, and Y^a represents a fluorine atom or a cyano group. where Y^b represents a hydrogen atom, a fluorine atom, or a cyano group, m represents 0 or 1, l represents an integer from 0 to 10, and C^* and C^*^* each independently ( Represents an asymmetric carbon atom with R) configuration or (S) configuration, Z^1 and Z^
2 each independently represents a single bond, -COO-, -OCO-, -
CH_2O-, -OCH_2-, -CH_2CH_2-
, -C≡C-, -COS- or -SCO-, Z
^3 represents a single bond, -COO-, -OCO-, -O-, or -S-, and ▲There are mathematical formulas, chemical formulas, tables, etc.▼ and ▲There are mathematical formulas, chemical formulas, tables, etc.▼ are each independent. ▲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.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and Y^1 and Y^2 represent hydrogen atoms or fluorine atoms. Chiral smectic C containing an optically active compound represented by
A ferroelectric liquid crystal composition exhibiting a phase. 2, Z^1 and Z^2 are each independently a single bond, -COO
- or -OCO-, Z^3 is a single bond, -COO-
, -OCO- or -O-, and one of ▲There are mathematical formulas, chemical formulas, tables, etc.▼ and ▲There are mathematical formulas, chemical formulas, tables, etc.▼ is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and the other 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. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas,
2. The ferroelectric liquid crystal composition according to claim 1, which has tables, etc. ▼ or ▲ has mathematical formulas, chemical formulas, tables, etc. ▼. 3. When cooling from an isotropic liquid state, 3 degrees or more 3
In the temperature range from the temperature at which the chiral nematic phase undergoes a phase transition from the chiral nematic phase to a phase on the lower temperature side through a chiral nematic phase having a temperature range of less than 0 degrees to the temperature 1 degree higher than the phase transition temperature, the chiral nematic 3. The ferroelectric liquid crystal composition according to claim 1, wherein the phase has a helical pitch of 3 μm or more. 4. The ferroelectric liquid crystal composition according to claim 3, which undergoes a phase transition to a chiral smectic C phase via a smectic A phase having a temperature range of 1 degree or more and less than 30 degrees upon cooling from a chiral nematic phase.