JPH02191695A - Ferroelectric liquid crystal composition - Google Patents

Abstract

PURPOSE:To obtain a ferroelectric liquid crystal composition having quick response and excellent orientation property by adding a chiral dopant containing a specific optically active compound to a liquid crystal composition exhibiting smectic C phase and composed of a medium-temperature region matrix liquid crystal and a viscosity-reducing liquid crystal. CONSTITUTION:The objective composition is produced by adding (A) a chiral dopant composed of an optically active compound of formula (X is core part; R1* and R2* are optically active group containing hetero atom) to a liquid crystal composition exhibiting smectic C phase and composed of (B) an optically inactive medium-temperature region liquid crystal exhibiting smectic C phase and containing (i) a liquid crystal compound exhibiting smectic C phase and having bicyclic structure or tricyclic structure containing cyclohexyl ring or (ii) a homolog of the component (i) and (C) an optically inactive liquid crystal composition exhibiting smectic C phase and consisting of a viscosity-reducing liquid crystal having bicyclic structure, containing <=1 ester bond and having alkyl group as at least one of both side chains.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a novel liquid crystal composition useful as an electro-optical display material, and in particular provides a liquid crystal material having ferroelectricity, which is different from conventional liquid crystal compositions. The object of the present invention is to provide a liquid crystal material that has particularly excellent responsiveness and memory performance compared to liquid crystal materials, and can be used for liquid crystal display elements.

[Prior art]

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

However, in liquid crystal devices using ferroelectric smectic liquid crystals, the 100 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 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 crystal belongs to the tilted chiral smectic phase, and among them, the one that is practically desirable is chiral smectic C (hereinafter abbreviated as SC'''), which has the lowest viscosity. ) phase.

[Problem to be solved by the invention]

Liquid crystal compounds exhibiting the SC phase (hereinafter referred to as SC2 compounds) have been studied and many compounds have already been synthesized.
``The compound alone must meet the following conditions for use as an optical switching element for ferroelectric liquid crystal displays: (a) It must exhibit ferroelectricity over a wide temperature range including room temperature, and (b) It must have an appropriate phase at high temperatures. (b) Particularly chiral nematic (hereinafter abbreviated as N1).

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

Therefore, the current situation is that liquid crystal compositions exhibiting an "SC" phase (hereinafter referred to as "SC" 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 N" phase in the high temperature range of the SC8 phase, a method of increasing the length of the helical pitch 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 S01 phase and the N'' phase, the orientation will be better. It is also known that it is possible to use a combination of an optically active substance that causes a right-handed helix, and an optically active compound that causes a right-handed helix. (It is already a known technique to adjust the length to an arbitrary length.) However, although these techniques can provide good orientation, they do not necessarily provide high-speed response.

In order to exhibit high-speed responsiveness, for example, as shown in the special lecture at the 12th Liquid Crystal Conference (Proceedings of the same conference, p. 98), low viscosity smectic C (hereinafter abbreviated as SC) is used. ) phase (hereinafter referred to as SC matrix liquid crystal) has a spontaneous polarization (hereinafter abbreviated as Ps).

) is superior.

According to this method, the ratio of the optically active compound that produces the spiral is reduced, so the spiral pitch becomes relatively long. It is necessary to reduce the amount of ions, which causes the problem that the spontaneous polarization becomes too small, making it impossible to obtain high-speed response.

Furthermore, those that have been used hitherto as SC matrix liquid crystals are described in, for example, Japan Display 86 Lecture Proceedings (from page 352) or Japanese Patent Application Laid-open No. 1983-583.

(R, R' represent an achiral alkyl group.) (R,
R' is the same as above. ), compositions containing a liquid crystal compound in which the compound itself or its homologues are limited to those exhibiting an SC phase, or in addition have a strong polarization in the direction perpendicular to the long axis of the molecules. However, there were problems in that the viscosity increased and the response became slow.

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 for Solving the Problems) In order to solve the above problems, the present invention provides a liquid crystal composition (
The general formula (A) R+"X Rz" ・= (A
) is added with a chiral dopant containing as a constituent component at least one optically active compound having different chiral groups as both chains of the molecule.
09 liquid crystal composition is provided.

The SC matrix liquid crystal used in the present invention is characterized by being composed of a medium temperature range matrix liquid crystal and a reduced viscosity liquid crystal. is a two-ring or three-ring structure, and in the case of a three-ring structure, at least one ring is a cyclohexyl ring, and the compound exhibiting an SC phase, or the number of carbon atoms and structure of its alkyl chain only. consists of homologs with different
It is a compound that exhibits an SC phase that may be monotropic in a range of degrees above CO. However, in the case of a three-ring structure, S
It is a liquid crystal whose upper limit temperature of C phase is less than 90°C, and 10
It exhibits an SC phase which may be monochromatic pink in any temperature range of 10°C or more between 80°C and 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 represents an alkyl group having 1 to 1 carbon atoms.

(1-a) (1-a-23) (I-a-24) R1(n(toCOR1) RlO (proof (warm 0CORz) (1-a-27) R, Coo ((Kun koR.

-N (1-a-29) R,0CO((叉婬し01?

-N (1-b) (1-c) (1-c-14) RIO+C00 0COOR1 (1-c-15) RIO 1 C00 (deception COOR1 (I-c-17) RIC00+C00 moxibustion C0OR.

(1-c-19) (1-c-20) RIOCO ((C00+C00Rz R, 0 building COO+C00Rt (1-d7 (1-e) (r -e-1) (r -e-2) (Lf) Among the above compounds, compounds represented by formulas (I-a) and (I-b) are preferred, and formulas (1-a-1), (
1-a-5), (I-a-4,1) and CI-b-
Particularly preferred are compounds represented by 1>.

The SC base liquid crystal used in the present invention contains, in addition to the above medium-temperature range base liquid crystal, a viscosity-reducing liquid crystal for the purpose of reducing its viscosity and improving responsiveness.

The viscosity-reduced liquid crystal herein refers to an optically inactive, low-viscosity liquid crystal compound or composition, and the constituent low-viscosity compound has a two-ring structure and does not necessarily have to exhibit an SC phase. is a compound which contributes to improvement of responsiveness by being added to a medium-temperature range host liquid crystal, and at least one of both groups is an alkyl group, particularly preferably a compound in which both groups are an alkyl group, It is characterized in that the number of ester bonds contained within the molecule is one or less.

Typical compounds used as viscosity-reducing liquid crystals are listed below. However, in the general formula shown below, R+
, Rz each independently represents an alkyl group having 1 to 12 carbon atoms.

(II-a) / , / Yu' / (II-b) (II-c) (II-d) (ne-e) When the proportion of the above-mentioned viscosity-reducing liquid crystal in the SC base liquid crystal in the present invention is too small However, the effect of lowering the viscosity is not sufficient, and as a result, there is no significant improvement in response.Also, if the proportion of the viscosity-reducing liquid crystal increases too much, the temperature range of the SC phase becomes narrower, so the proportion of the viscosity-reducing liquid crystal increases. is preferably in the range of 3 to 50% by weight, particularly preferably in the range of 5 to 25% by weight.

The SC matrix liquid crystal obtained in this way has extremely low viscosity,
By adding a chiral dopant, a high-speed response SC" liquid crystal composition can be easily obtained.

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

In general formula (A), R- and R,11 are mutually different optically active groups, R,11 and R1*
At least one of 0, N, S, F, , Cj! is an optically active group containing at least one heteroatom such as or any one or two or three non-adjacent -CH7- in the alkyl group independently represent 10-
-S--coo--oco~ -cos--5co--
c-may be substituted with -3-, and the alkyl group Y! Any 1 to 2 -CH,- in -c-(y, and Y
3 are different from each other, H, F, fJSClh, CPf
f, 0CHs or CN. ), and any -CH! in the alkyl group may be substituted with -CHl- is-
CI = C)! - or -〇miC- may be substituted, and any -CH in the alkyl group! -Ha-CF!
- may be substituted with -CH3 in the alkyl group
is preferably an optically active alkyl group which may be substituted with -CFff.

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), and any 1 to 2 -C in the ring
H2- may be substituted with -0--5--IJH--C--CH-, or may be substituted in the ring. Y represents a fluorine atom, a chlorine atom, a cyano group, a methyl group, a methoxy group, and Z+, Zz or 2.
are each independently a single bond, -coo--oco-CH! O
OCH* CLCHg c=c- is -CH
-C) Represents I-, z4 is -CHz CHzC
1 to 2 -CH- in Ih- represent -5-1 or -0- substituted with -N- or -C=, and m and n each independently represent O or 1. ) It is preferable that the central skeleton (core) portion is represented by:

Of the central skeleton represented by X, Representative things are listed below.

(V-36) ■ Tobako'8-o, A fluorine atom, chlorine atom, bromine atom, methyl group, methoxy group, cyano group, or nitro group is present in the benzene ring or cyclohexane ring in each of the above basic skeletons. Substituted basic skeletons can also be used.

Next, in the general formula, R- and R? Among the optically active groups represented by, typical ones are shown below (IV
-7') CH.

1 umbrella (’-CH!÷T-CH-g.

Listed below.

(IV-1) CD.

1 umbrella + CHt +T-CD CtHs (IV-8) CH3 -0(-CIb+T-CHR3 (IV-2) CH3 1. -0(-CIh+rCHC!)Is (KV-3) CHt + CHg□ O+ C)It +rCHC! )Is
(IV-4) C11゜1・-Of CHzh-0+ CHt '+'i-CHCJ
s(IV-12) LjSyn-CHRa (IV-13) CHt 1 umbrella-C) It-CHCHz 0Rs (rV-21) CH3 1. -5+ CHz +i-C[I(CHzhi-CHt(
IV-32) CH3 -0-CH-R4 (IV-20) -0-CHt If-CthL:tltL;th
-1-L; H Go (IV-35) -0-CH-C1, -L; II-υ 5 (IV-53) CH3 HORs (IV-55) 1 skew OCHz CHRs (lV -4! () L; ML; Lll; 11z-shi■14 (IV-57) l (- OCH! -69) CHl.

1・ -COOCHz CJI Rs (IV-64) CH.

OCHz CHC1b 0Rs (IV-70) Hff 1◆ -OC8! CHC11z 0CORs (IV-6
5) CH3 -OCRCHl 0Rs (IV-71) CHl OCHCHl OCOR5 (IV-66) CI.

-0-f CHz+rCH(CHzY"0Rs(IV-
72) CNyuOCM CTo(CHz)i-OCORs(It/-
67) -COOCHI Ctl Ctl Cu
rls(IV-73) CHl OCHz-CH-(C1(*)ii-OCORs(IV
-80) COOCTo CN Rs (IV-75) Hff -〇-C)l□-CH0Rs (IV-81) CN 1・OCHz CHRs (IV-76) Chz -S-C1l -R5 (IV-82) CN 1 Umbrella CHRs (IV-83) HICN -Coo -CH2-CH-Rs (IV-78) Js 1・OCHz CH0Ra (IV-84) C)lICN I・OCHt CHRs CH3 In each of the above general formulas, m is Represents an integer from 1 to 4, n
represents an integer from 1 to 10, R3 represents an alkyl group having 3 to 8 carbon atoms, R6 represents an alkyl group having 2 to 10 carbon atoms, and R3 represents an alkyl group having 1 to 10 carbon atoms. where R9 represents an alkyl group having 1 to 4 carbon atoms.

Optically active compounds containing only optically active groups represented by ⑐ (IV-1) to (■-22) as optically active groups are:
Even when the spontaneous polarization induced when added to the SC matrix liquid crystal to form an SC" liquid crystal composition is very small and exhibits an SC" phase by itself, most of it is 10 n C70m".
No more than the following.

On the other hand, as optically active groups -1 formula (IV-31) ~ (■9
In the case of an optically active compound containing an optically active group represented by 1), the spontaneous polarization induced when used as an S00 liquid crystal composition is large, and in cases where it alone exhibits a sc'' phase, it is 300 n.
There are some that exhibit a large value of C/cmi" or more. The chiral dopant in the present invention has a somewhat large spontaneous polarization even when added in a small amount, and preferably, when added at 10% in the SC matrix liquid crystal, the upper limit of the S00 phase 10” of temperature
On the low temperature side: 1. It is desirable to induce spontaneous polarization of on C70m" or more, and R + R
2, at least one is (IV-31,) ~ (■-9
It is desirable to contain at least one compound that is a group represented by 1).

Preferred compounds with combinations of R, ", R1", and X are listed below.

CH.

In the above general formula, R4, R, and l each independently represent an alkyl group having 2 to 10 carbon atoms, and R1 and R , t each independently represents an alkyl group having 1 to 10 carbon atoms,
R? 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
represents an optically active alkyl group containing 0 at least one asymmetric carbon atom, and! represents an integer from O to 5, and Y
is a single bond, -o-, -oco-, -coo-, or -o
coo~, W is a chlorine atom, a fluorine atom, or -
0-CI (, Z' represents -COO0CO-, CHzO, 0CHz, or as other constituents of the chiral dopant in the present invention, only one side chain of the liquid crystal molecule is optically active. Certain compounds can be used.Among such compounds, particularly preferred ones are listed below.

CH, 1 book (Vl-b-1) R"-Z' -COOC
II-R.

(Vl-b-2) C11゜ I. R”-Z’　-0-CI(-1?.

(VT-b-3) uff 1・R"Z' C00CRC00Rs (Vl-b-
4) Hs 1・R-Z'-COOCii-OR5 (Vl-b-5
) CH3 1・R-Z'-C00C)I-CI□-0R2(
Vl-b-6) C11゜1・R"Z' -〇〇〇GHz C1(ORs(V
l-b-7) CI'+3 1・R"Z' OCHCHxORs(VI-b-8
) R"-Z' C11°OCToCfl OR% (Vl-b-9) C1l.

R'Z' OCRC00Rs L (Vl-b-1,1) R'Z' OCO
In the C1f ORs formula, R1 is an alkyl group having 1 to 20 carbon atoms, an alkoxy group, an alkanoyloxy group, an alkoxycarbonyl group, an alkoxycarbonyloxy group,
or represents an alkoxyalkyl group, Z', R,, R,
, R, , W each represent the above-mentioned meaning.

In the chiral dopant, it is desirable to use the compound represented by the general formula (A) in an amount of 10% by weight or more, preferably 30% by weight or more, and 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 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 base liquid crystal, the viscosity of the S01 liquid crystal composition increases, which tends to have a negative effect on high-speed response, so this is preferable. 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 becomes too small and high-speed response cannot be expected.

The spontaneous polarization value of the S01 liquid crystal composition is 3 to 30nC/
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 spontaneous polarization, the addition ratio of the chiral dopant is preferably in the range of 10 to 40% by weight, and 300 n
In the case of a chiral dopant that exhibits strong spontaneous polarization of C/cd or higher, the addition ratio of the chiral dopant is 2 to 25% by weight.
A range of is preferred. The stronger the spontaneous polarization induced by the chiral dopant, the lower its most desirable addition ratio;
In the case of the chiral dopant made of the optically active compound exemplified, the addition ratio thereof is usually not less than 1% by weight.

When the SC" liquid crystal composition of the present invention is cooled from an isotropic liquid state, it first undergoes a phase transition to the N" phase, and then passes through the SA phase or directly to the SC" phase. In this case, the temperature range showing the N0 phase is preferably in the range of 3° or more and 30° without dripping.If the temperature range showing the N0 phase is less than 3 degrees, the phase transition to the SA phase will occur promptly when the temperature is lowered.
This is not preferable because it tends to make it difficult to fully align liquid crystal molecules in the N1 phase. In addition, the temperature range showing the N1 phase is 30
If the temperature exceeds 1, the clearing point of the S09 liquid crystal composition becomes high, which tends to adversely affect workability in the step of filling the cell with liquid crystal material, etc., which is not preferable.

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 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 N phase is exhibited, or an SC base liquid crystal that does not exhibit the N phase is used.
A base liquid crystal may be used, and in the case of (2), an SC base liquid crystal that exhibits an N phase over a wide temperature range may be used. This method can be applied not only to the N1 phase but also to the SA phase and SC9 phase. For example, in the case where the chiral dopant expands only the SA phase of the SC3 liquid crystal composition and reduces the N'''' phase and the SC1 phase, as the SC base liquid crystal, the upper limit temperature of the SC phase is high and the temperature of the N phase is The range is wide;
In addition, it is sufficient to use one having a phase sequence of SC phase→N phase→r phase, or one having a narrow temperature range of SA phase and having a phase sequence of SC phase→SA phase→N phase→I phase.

Such a chiral dopant tendency can be easily determined by measuring the change in phase transition temperature of an SC0 liquid crystal composition obtained by adding a certain amount of chiral dopant to an SC base liquid crystal. From this result, it is possible to easily adjust the temperature range in which each phase in the SC0 liquid crystal composition exhibits, especially the N'''' phase.

Furthermore, every time the helical pinch that appears in the N' phase is 3 μm or more from the temperature at which the N* phase transitions to the SA phase or SC'' phase (lower limit temperature of the N'' phase) to the 1° higher temperature side, Preferably, the helical pitch is 108 m or more, and an SC'' liquid crystal composition in which the helical pitch increases divergently as the lower limit temperature of the N'' phase is approached is particularly preferable for improving alignment.

When an optically active compound represented by the general formula (A) is used as a component of a chiral dopant in an uninvented invention, an SC liquid crystal composition with a long helical pitch that satisfies the above conditions even if it is a single compound. However, in general, as long as the concentration of the chiral dopant is within a practical range, the helical B, ·, and C do not necessarily satisfy the two conditions.

In that case, in order to adjust the helical pitch to the above-mentioned preferred range, add SC to the SC matrix liquid crystal.

When a liquid crystal composition is prepared, it is necessary to prepare a chiral dopant by adding at least one optically active compound whose helical directions that appear in the N* phase are opposite to each other.

The helical pitch (-P (μm)) that appears in the N0 phase of the SC'' liquid crystal composition containing multiple optically active compounds is the concentration of each optically active substance, Ci, and the helical pinch per unit concentration, P.
i (,!/l1l) (Here, the right-handed spiral pitch is positive and the left-handed spiral pitch is negative.) Using this, Pl at the SAN'' point T0 of the SC0 liquid crystal composition is
When PP is set, Ci can 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, To changes depending on each C4, but it can often be estimated quite 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 value T, / and the To of the composition selected using it are significantly different, then T,
The measurement may be performed again using To instead of r.

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, for the S00 liquid crystal composition, the amount of chiral dopant added may be adjusted so that the value of P is in the range of 3 to 30 nCicd, especially near room temperature.
However, when the value of P8 induced by chiral doban 1- is small, the amount added is large relative to the SC base liquid crystal, and the viscosity of the SC″′ liquid crystal composition increases accordingly. This is not preferable because it tends to make it difficult to obtain high-speed response.Therefore, the chiral dopant used in the present invention should be added to the SC matrix liquid crystal by 10 times %.
When added, 1. On
Particularly preferred is one that can induce P of 5 n Clcd or more.

/ / / [Examples] 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, "%" 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.

Examples] (Preparation of chiral dopant) scI (a compound that causes the appearance of a right-handed helix in the N" phase when added to a one-body liquid crystal to form an SC0 liquid crystal composition) is represented by the formula (2). The helical pitch that appears in the N8 phase when 10% is added to the SC matrix liquid crystal shown is 4.7 μm at 60''C. When 10% of is added to the SC base liquid crystal shown below, the helical pitch that appears in the N'' phase is 11.9 μm at 60 ° C.). Chiral dopants with controlled helical pitch were prepared.

Hereinafter, it will be referred to as chiral dopant (A).

The SC matrix liquid crystal used in Example 1 is a composition consisting of
, 5'C or less showed an SA phase and 69"C or less showed an N phase, and the melting point was 14°C.

Example 2 (Preparation of chiral dopant (2)) was mixed to prepare a chiral dopant in which the helical pitch appearing in the N'' phase was adjusted.
SC" phase below C, SA phase below 70.5'C, 71,
It exhibited an N'' phase below 5°C, and its melting point was 31'C.

Hereinafter, it will be referred to as chiral dopant (B).

Example 3 (Preparation of chiral dopant (3)) Example 4
(Preparation of chiral dopant (4))) to prepare a chiral dopant whose helical pitch was adjusted to appear in the N1 phase. This chiral dopant exhibited a high-order chiral smectinic phase at temperatures below 56.5°C and an N0 phase at temperatures below 65°C, and its melting point was 55°C.

Hereinafter, it will be referred to as a chiral dopant (C).

A chiral dopant with an adjusted helical pitch that appears in the N1 phase was prepared by mixing the above.

Hereinafter, it will be referred to as a chiral dopant (D).

Example 5 (Preparation 1 of SC" liquid crystal composition) A compound of formula (1-b-1) was used as a medium-temperature range host liquid crystal, and a compound of formula (1-b-1) was used as a thinning liquid crystal.
II-a-6), and chiral dopane l-(A
) An SC0 liquid crystal composition having the following composition was prepared.

(1-b-1) (II-a-6) n-CJ+s(HΣC00% n-Ca H+ t1
6% chiral dopant 20% This composition exhibits the sc” phase below 62°C and the SA phase below 73°C.
The phases each exhibited an N3 phase below 79°C. The helical pitch of this composition at 73.1'C was 10 am 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.

The orientation treatment was performed by polyimide rubbing on one side, and the filled and oriented cells were subjected to an electric field strength of 10 V and 7 μm.

When a 50 Hz rectangular wave was applied and the electro-optical response speed was measured, it showed a high-speed response of 62 μsec at 25° C., and the contrast was also good.

The tilt angle at this time was 19.1°, and the spontaneous polarization was 19.4n.
C/aa”.

Example 6 (SC" liquid crystal composition made of steel 2) In Example 5, in place of the thinning liquid crystal of formula (II-a-6), formula (II-a-6) was used.
-b -1,) compound n-C5H+ t +0CH
t8n-C*HI? An SC'' liquid crystal composition was prepared in the same manner as in Example 5, except that .

This composition exhibited an SC8 phase up to 61°C, an SA phase up to 65°C, and an N'' phase up to 70.5°C.

When the optical response speed was measured in the same manner as in Example 5, it showed a fast response of 37 μsec at 25° C., and both orientation and contrast were good. The tilt angle at this time is 31.3°, and the spontaneous polarization is 25.5 n C7c
It was "m".

Example 7 (Preparation of SC''' liquid crystal composition 3) The compound of 2(1-1)-1) was used as the medium-temperature range host liquid crystal, the compound of formula (■-a-1) was used as the viscosity-reducing liquid crystal, and the chiral dopant (B
An SC" liquid crystal composition having the following composition was prepared.

(1-b-1) ri-CJIJ4COO80-n-C61+t 14
%(III-a-1) Chiral dopant (B) 30% This composition showed an SC" phase at 60°C or lower, an SA phase at 71°C or lower, and an N" phase at 78°C or lower. .

When its optical response speed was measured in the same manner as in Example 5, it showed a fast response of 119 μsec at 25°C.
Both orientation and contrast were good.

Example 8 (Preparation of SC" liquid crystal composition 4) A compound of formula (1-a-1) as a medium-temperature host liquid crystal, a compound of 2 (U-a-6) and chiral dovan i-(B) as a viscosity-reducing liquid crystal.
An SC" liquid crystal composition was prepared.

(I-a-1) (U-a-6) This composition has a sc” phase up to 36°C and an SA phase up to 61°C.
phase, N'' phase up to 62°C, respectively.

When the optical response speed was measured in the same manner as in Example 5, it showed a fast response of 99 μsec at 25° C., and both orientation and contrast were good.

Example 9 (Preparation of SC" liquid crystal composition 5) In Example 8, the formula (ff-
a-1) compound n-CH6) f214COO4n-C
An SC'' liquid crystal composition was prepared in the same manner as in Example 8, except that J+s was used and the chiral dopant (C) was used instead of the chiral dopant (B).

This composition has a SC phase below 47.5"C, 59°
Below C, each showed the N1 phase.

When the optical response speed was measured in the same manner as in Example 5, it showed a fast response of 48 μsec at 25° C., and both orientation and contrast were good.

Example 1 Preparation of "ocse" liquid crystal composition 6) Compound of formula (1-a-1) as medium-temperature host liquid crystal, compound of formula (U-b-1) and chiral dovan l-(D) as thinning liquid crystal
An S00 liquid crystal composition having the following composition was prepared.

(1-a-1) (fJ-b) The composition showed an SC0 phase up to 52.5°C and an SA phase up to 59°C.

When its optical response speed was measured in the same manner as in Example 5, it showed a fast response of 40 u, seconds at 25°C, and both orientation and contrast were good.

[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 smectinic liquid crystals.

teenager Reason Man

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 (b) a homologue of the compound that differs only in the number of carbon atoms or structure of the alkyl chain; and (2) a medium-temperature liquid crystal exhibiting a smectic C phase that is optically inactive and has a two-ring structure. A liquid crystal composition exhibiting a smectic C phase consisting of a reduced viscosity liquid crystal consisting of a compound in which at least one of both chains is an alkyl group and one or less ester bonds are contained in the molecule; (3) an optically active compound; A ferroelectric liquid crystal composition containing a chiral dopant consisting of a compound, the optically active compound having the general formula (A) R_1^*-X-R_2^* (wherein, X is the central skeleton of the liquid crystal molecule). R_1^* and R_2^* represent mutually 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. 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 lower temperature phase to one degree higher than the phase transition temperature through a chiral nematic phase having a temperature range of less than 0 degrees, 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. .