JPH02247282A - Ferroelectric liquid crystal composition - Google Patents

Abstract

PURPOSE:To obtain the subject novel composition, excellent in responsiveness and orienting properties and capable of exhibiting a chiral smectic C phase within a wide temperature range including ambient temperature by blending a composition consisting of respective specific matrix liquid crystal within a medium temperature region and viscosity reducing liquid crystal with a special chiral dopant. CONSTITUTION:The objective composition obtained by blending a composition, containing (A) a matrix liquid crystal within a medium temperature range which is a composition consisting of an optically inert liquid crystal compound having a bycyclic structure or homolog thereof in which the above-mentioned homolog may be monotropic within an optical temperature width of >=1 deg.C at >=10 deg.C and capable of exhibiting a smectic C (SC) phase and (B) a viscosity reducing liquid crystal which is a composition containing an optically inert compound having side chain of an alkyl and containing <=1 ester bond in which the above-mentioned compound will not exhibit the SC phase alone including the homolog and capable of exhibiting the SC phase with (C) an optically active compound expressed by formula [R<1> is 2-10C alkyl; R<2> is 1-10C alkyl; Z<a> is O or COO; X is formula II or III (Z<1> to Z<3> are OCO, etc.: m is 0 or 1), etc.] as a chiral dopant.

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

[Problem to be solved by the invention]

Liquid crystal compounds exhibiting an SC'' phase (hereinafter referred to as SC''1 compounds) have been studied, and many compounds have already been synthesized. However, these S
The C1 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) having appropriate phase stability in a high temperature range. The presence of a series (c) Particularly chiral nematic (hereinafter abbreviated as N'').

) exhibiting a long helical pitch in the phase; (d) having an appropriate tilt angle; (e) having low viscosity; (f) having a large value of spontaneous polarization above a certain level. 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 SC1 liquid crystal compositions) are currently being used for studies and the like.

In order to obtain good orientation, for example, JP-A-61-1
As shown in Japanese Patent No. 53623, etc., in a liquid crystal having an N'' phase in the high temperature range of the SC2 phase, it is generally effective to increase the length of the helical pinch of the N' phase.In this case, The orientation is better when the smectic A (hereinafter abbreviated as SA) phase is present in the temperature range between the S01 phase and the N4 phase, and in order to increase the helical pinch, an optically active substance that causes left helix and an optically active substance that causes left helix are used. It is also known that it is possible to use a combination of optically active compounds that produce a right-handed helix (nematic (hereinafter abbreviated as N)). (Adjusting the length is already a known technique.) However, although these techniques can provide good orientation,
High-speed response could not be obtained.

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

) large SC.

The method of adding compounds is excellent. According to this method, the proportion of the optically active compound that produces the helix is small, so the helical pitch is relatively long. Therefore, there was a problem in that the spontaneous polarization became 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.

RO+COO-@-OR' (R, R' represent an achiral alkyl group) (R
, R' are the same as above. ), the compound itself or its homologues are limited to those exhibiting an SC phase, or compositions in which a liquid crystal compound is added that exhibits a strong dipole (polarization) in the direction perpendicular to the long axis of the molecule. However, if the temperature range of the SC phase is kept wide, the viscosity increases, and if the viscosity is decreased, the temperature range of the SC phase becomes narrow.

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

The problem to be solved by the present invention is to provide a ferroelectric liquid crystal composition that is fully satisfactory in both high-speed response and orientation.

[Means to solve the problem]

Provided is an SC"liquid crystal composition exhibiting an SC1 phase in a wide temperature range including room temperature, which is obtained by adding a chiral dopant as a constituent component.

In the general formula (A), R1 represents an alkyl group having 2 to 10 carbon atoms, R2 represents an alkyl group having 1 to 10 carbon atoms, and Za represents 10- or -COO-.

C1 and C- each independently represent an asymmetric carbon atom of (R) configuration or (S) configuration, X is general formula (B) general formula (C), -form (A) or -form ( D) Any 1 to 2 -CH= of at least one optically active compound represented by l may be substituted with -N= or -C-, and any one in the ring may be substituted with -N= or -C-. ~2 pieces-
C1 (2- represents -0--S--NHl-CH2-C--5-1 or -〇-, m and n
each independently represents O or 1. ) represents the central skeleton (core) part of a liquid crystal molecule.

Particularly preferably, in -form (A), X is of the general formula (
E) It may be done. Y' represents a fluorine atom, a chlorine atom, a cyano group, a methyl group, or a methoxy group, and Z1Z2 or Z3 each independently represents a single bond, -COO-0co --C
)120- -0CI+□--CH2C)I2-S-C
-1 or -CH='C1+-, Z4 represents -C1(
Divalently represents a hydrogen atom, a fluorine atom, a chlorine atom, or a cyano group, but Y2 and Y3 do not represent a hydrogen atom at the same time. Zl, Z2 and m are the same as above. ) is a compound represented by

The SC base liquid crystal used in the present invention has a phase sequence of (a) I (isotropic liquid) phase → N phase → SA phase → SC phase on the high temperature side of its SC phase when the temperature is lowered (b) (3) A phase having a phase sequence of 3A phase → SC phase (3) A phase sequence of I phase → N phase - 3C phase, or (d) A phase sequence of I phase - 8C phase. Although those having a series are used, the selection of (a) to (d) differs depending on the chiral dopant used at the same time. The most commonly used method is (a), in which 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, then (b) is added to 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 SA phase and narrow the temperature range of the N''' phase, select (c), or if the SC property is weak, narrow the temperature range of the N'' or SA phase. It is most suitable to use (d) when it is easy to spread. What is important is the phase series in the case of S09 liquid crystal composition,
- For boat fishing, the phase sequence r→N1→SA→SC" is advantageous in terms of orientation. On the other hand, the phase series ■→N1→SC1 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.

As the SC base liquid crystal used in the present invention, a composition consisting of a compound exhibiting an SC phase as conventionally used can be used, but in order to obtain faster response, the composition shown below can be used. is more preferable.

That is, (I) a composition (hereinafter referred to as a medium-temperature host liquid crystal) consisting of a compound that has a two-ring structure and exhibits an SC phase at a temperature close to room temperature or a homologue thereof (a compound that differs only in the alkyl chain); (2) It is a composition that has a two-ring structure, has few polar groups in the molecule, and has a low viscosity compound (hereinafter referred to as viscosity-reducing liquid crystal) added to lower the viscosity and improve responsiveness.

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

Typical compounds used as medium-temperature host liquid crystals are listed below. However, in the general formula shown below,
R1 and Rz each independently represent an alkyl group having 1 to 18 carbon atoms.

(1-a) (1-a-46) (1-a-47) (1-a-48) (1-a-49) (I-a-50) (I-a-51) (I-a-52) (r　-a-53) ...(wet voice) C0R2 R, Takumi ¥ (warm C00RZ ...Zumaga C0Rz R10 (Ruga 0ORZ Haruka Buya R, Coo Ill.

1st place - RICOO0Rz (buying music) RI COO0COR2 R+COO letter , N, C0OR・ (■ b) (Lc) (I-c-29) R,0CO (anti-COO-0-OR.

-N (I d) (If) Reduced viscosity liquid crystal The reduced viscosity liquid crystal used in the present invention is a low viscosity liquid crystal compound or composition, and the constituent low viscosity compound has a two-ring structure, and when used alone, Homologues that differ only in alkyl chains do not exhibit an SC phase, but when added to a medium-temperature host liquid crystal, they contribute to improving responsiveness, and at least one of the chains on both sides is an alkyl group, Particularly desirable are compounds in which both chains are alkyl groups, and the number of ester bonds contained in 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,,
Each R2 independently represents an alkyl group having 1 to 12 carbon atoms.

/ / (II-b) (II-c) (U-c-20) Rbehe CH, CI(, ◇XR2 (II-c-21) R, 0sha C)1. C■2 building R2 (■ R+C0O-(E)-CHzCHzshaR2(n-d) d-29) (U-d-30) (n-d d-32) R8 is also X←R2 R, lever! ←R2 R, nifilter OR2 1m0R2 R1 captive: +0”2 (Il[-d-33) R, dumb OR.

(n - d - 34) R, f ORz Among the above compounds, the formula (1
-a) and the compound represented by the formula (1-b) are preferred, and the compounds represented by the formula (1-a-1), the formula (I-a-2), and the formula (I-a-
5), 2 (1-a-41L formula (1-a-42) and formula (
Particularly preferred are compounds represented by I-b-1). As the viscosity-reducing liquid crystal, compounds represented by formula (II-a) and formula (II-b) are preferable, and compounds represented by formula (II-a-1), formula (
Particularly preferred are compounds represented by formula (II-a-6) and formula (II-b-1).

The blending ratio of the medium temperature range base liquid crystal is 40 to 9 of the SC base liquid crystal.
9% by weight is preferred, and 60-90% by weight is particularly preferred.

The chiral dopant used in the present invention includes (1) S
A compound exhibiting a C" phase, (2) a compound exhibiting only a liquid crystal phase other than the SC" phase, or (3) a compound exhibiting no liquid crystallinity at all can be used; however, in the case of (3), the SC matrix In order to prevent the tendency for the liquid crystallinity of the SC9 liquid crystal composition obtained by adding it to liquid crystal to decrease, it is preferable to use a compound having a skeleton similar to that of liquid crystal.

Among the various physical properties that a chiral dopant brings to an SCI liquid crystal composition, the important ones are the helical pitch it induces, the direction and magnitude of spontaneous polarization, and these depend on the optical activity of each compound constituting the chiral dopant. It is most affected by the body part.

Typical optically active groups in optically active compounds that have been used as chiral dovants, SC2 compounds, or additives to nematic liquid crystals are listed below.

(IV-5) 0　　　　　　　C)I.

II 1゜CO+ CHz +rC)l C2H3 (IV-6) 0 CH3 111゜-0-C+ CHz+-CHCJs L (IV 1) + CHz-+Te1l
Czlls (TV-7) CH.

(-CHz-)T-CHR3 (IV-2) C1(3 -0(-CH2+rCHC2)Is (IV-3) CH.

+ CH2)r-0-(-CI(2-h-Cl-C2H
5LIV-! :1J-c-ot cttz→7[;H-pi3(IV-12
) CH3 -CH-1'! .

(IV-13) CH2 CH.

CH-CH.

R5 (IV-14) C11゜-C1l CH20R5 (IV-32) CH3 -O-CH-R4 (IV-'(bJ -L; -u -Ull -un-υ 5(rV-16
) ~0-CHzGHz-CFI CH2CH2C1(ZH
3 CH CH.

(TV-20) CL CL O-CHz COCHzC) IzCHz-CH-C1
h0 0I l -C-0-CH2-CH-R5 (IV-57) CI 0-CIl□-CH (TV-53) CFI.

-CH-0-R5 OCHz CH’Rs (IV-62) F3 -O-CH-R.

(IV-64) C.I.

-0-CH, -CH CI (20R5 (IV-65) CH.

-0-C)I CH, -OR.

(IV-66) CH.

0 ”'f CFI2 ”'e”'r' CH (CHz
) i-OR5 (IV-69) Cj2 -COOCHz CHRs (IV-70) CH.

OCHz l CH20COR5 (IV-71) CH3 -0-CI-CI(2 0-COR.

(IV-72) CH.

OCHC)lx(CHzh-OCORs(IV-73) 0-CHI CH.

CH-(CHt)i-OCORs (IV-80) COOCTo　C)l　Rs (IV-81) C.N. OCHz (tHRs (IV-82) C.N. -CHRs (IV-83) C) I, CN -COOCHt CHRs (■-84) CH,CN OC) lx CHRs CH3 0CHZ CHI 0Rs (TV-76) L -3-CIl-R5 (IV-78) C,)I.

OCHz CH0R6 (IV-79) 10-C-0- to H l13 In each of the above formats, m represents an integer from 1 to 4, and n
represents an integer from 1 to 10, R1 represents an alkyl group having 3 to 8 carbon atoms, R4 represents an alkyl group having 2 to 10 carbon atoms, and R3 represents an alkyl group having 1 to 10 carbon atoms. , R8 represents an alkyl group having 1 to 4 carbon atoms.

Optically active compounds containing only the optically active groups represented by IV-1 to IV-22 are induced when added to the SC base liquid crystal to form an SC1 liquid crystal composition. Spontaneous polarization is very small, and even when it shows SC0 phase alone, most of it is only 10 nC/cm'' or less.

On the other hand, as optically active groups, formulas (IV-31) to (N91
) When an optically active compound containing an optically active group represented by There are some that exhibit large values greater than "cv".

In the present invention, as one optically active group, the formula (IV-
43), and an optically active compound having a group represented by formula (IV-31) or formula (IV-32) as another optically active group as a component of the chiral dopant. shall be.

The direction of the helical pitch and spontaneous polarization is Φ on the right,
In the case of (R), it is e on the left.

In the case of (S), the left side is ■; in the case of (R), the right side is θ; and in the case of the optically active group (R) of formula (IV-32), the left side is ■.

When combined with Kyo (R)-〇-CH-0R', the helical polarization is canceled out and lengthened, and the spontaneous polarization is added, making it possible to obtain a compound that is extremely strong. Furthermore, the formula (
The length of the helical pitch induced in the N1 phase by each optically active group of formula (IV-43) and formula (IV-31) or formula (N32) is:
Formula (IV-31) <Formula (IV-43) <Formula (IV-
32), so the aforementioned (S) (■-43
) and (S) − (IV-31), the direction of the helical pitch is to the left, and the direction of spontaneous polarization is ■, (S) −
In the combination of (IV-43) and (R) - (IV-32), a compound can be obtained in which the direction of the helical pitch is to the right and the direction of spontaneous polarization is e. Using these, the helical pitch can be adjusted arbitrarily. It can also be adjusted.

Typical basic skeletons (X in -form (A)) of optically active compounds having such an optically active group at the end are listed below.

of / (V-18) -C weight))CHzCHz　G.

(V-42) Friend H0 Ba Europe (V-61) One dish dish N (V-63) ha) (V-64) −○a) (V-65) −〈：Example now (V-66) −〇Cold (V-90) Stone sweat OX...go (V-114) *)-ocbeko →) (V-138) ◇)OCH, phantom 8 now (V-162) ◇) ocu, -Qbehu (V-186) 6.Doc+tz-(’Note (V-210) -+　oCH24) (V-234) chobe locut() (V ℃丞入 (■ Go coo touya＼ (V 發co(Sagisu) (V-449) Combined CH Bargay＼ (ψ−450) Combined QC) I2-XK huge〉” 4\o, < (V-451) ℃≦1 (V-479) Co-co-in (V-501) world h place oco frame (■ Sobe Shun C) 120 Matsume ＼ (V-503) world) o o CH, Asu (V-504) Call: 4coo litigation (V ioco pine su (V-506) (b) OCI (20 cases) (V-507) )-@-ocH poem 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; )
, formula (V-7) ~ formula (V-9), formula (V-17), (
V-18), 2 (V-21), formula (V-22), formula (V
-25) to basic skeletons represented by formulas (V-274) are particularly preferred.

Specifically, for example, the following compounds can be mentioned.

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.

Also, among the basic skeletons listed above, those with left and right asymmetrical structures can also be used in the same way.

;■ In the above, C is a crystalline phase, N* is a chiral nematic phase, S,
indicates the smectic A phase, SC* indicates the xyl smectic C phase, and SX indicates the chiral smectic phase of unknown origin. If the phase transition temperature is not listed, it is either monotropic and crystallized and cannot be measured, or the melting point is unknown. cannot be measured because it does not crystallize.

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

Other constituents of the chiral dopant include the above formula (
V-1) to the basic skeleton of formula (V-539), formula (IV-
1) - any two optically active groups of formula (IV-'91),
Alternatively, a compound having one bonded as a side chain can be used. (However, this excludes compounds of -format (A).) The above chiral dopant is present in the SC matrix liquid crystal at
It is appropriate to add it in a proportion of 2% by weight and use it as an SC1 liquid crystal composition, but it is more preferable to add it in a proportion of 2 to 50% by weight. When 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 S00 liquid crystal composition increases, resulting in This is not preferable because it tends to have a negative effect on high-speed response. Further, an increase in the amount of chiral dopant added tends to shorten the helical pitch, which tends to adversely affect the orientation, which is not preferable. On the other hand, if the proportion of the chiral dopant added is less than 1% by weight, the spontaneous polarization becomes too small and high-speed response cannot be expected.

The spontaneous polarization value of the SC''' 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 100nC/cm", and in the case of a chiral dopant exhibiting an SC* phase, it alone exhibits spontaneous polarization of about 100nC/C11" or an equivalent amount. In the case of a chiral dopant that induces a strong spontaneous polarization, the addition ratio of the chiral dopant is preferably in the range of 10 to 40% by weight. The addition ratio of
A range of 2 to 25% by weight is preferred. The more the spontaneous polarization induced by the chiral dopant becomes stronger, the more the most desirable proportion thereof decreases, but in the case of the chiral dopant made of the exemplified optically active compound, the proportion thereof does not fall below 1% by weight.

The SC1 liquid crystal composition of the present invention undergoes a phase transition from the isotropic liquid state to the N0 phase, then to the SA phase, and then to the SC* phase, but the phase transition temperature from the VAN'' phase to the SA phase ( (hereinafter referred to as the N'''-3A point), from the point N''-3'
It is more preferable to use an SC1 liquid crystal composition in which the pitch of the spiral appearing in the N1 phase up to one degree higher than point A is 3 μm or more, and the pitch of the spiral is 10 μm or more, and the N′″-
Particularly preferred is the S01 liquid crystal composition in which the pitch of the helix increases divergently as it approaches the 3A point.

- Among the optically active compounds of type (A), in compounds where the helical directions induced in the N* phase are opposite to each other due to the chiral groups on both sides, the induced helical pitch is quite long. When using a chemical compound as the main component of a chiral dopant, adjusting the helical pitch is often unnecessary or easy; however, for boat fishing, the helical pitch can be adjusted to a longer length as follows. be able to.

The helical pitch P (μm) appearing in the N9 phase of the S01 liquid crystal composition containing multiple optically active compounds is determined by C1 representing the concentration of each optically active substance, and Pt representing the helical pitch per unit concentration of each optically active substance.
(μm) (Here, the right-handed spiral pitch is positive and the left-handed spiral pitch is negative.) Using this, SC
``5A-N'' of the liquid crystal composition Pl at point T0 is p, i
When , Ci should be selected so that . Here P
i 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 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 value T.' differs greatly from To of the composition selected using it, the measurement may be performed again using To instead of T and l.

The temperature range showing the N1 phase of the S04 liquid crystal composition of the present invention is:
A range of 3 degrees or more and 30 degrees without grooves is preferable.

If the temperature range in which the N1 phase is exhibited is less than 3, the phase transition to the SA phase will occur immediately when the temperature is lowered, making it difficult to align liquid crystal molecules sufficiently in the N'' phase, which is undesirable. If the temperature range showing the phase is 30 degrees or higher, the clearing point of the SC liquid crystal composition becomes high, which tends to have an adverse effect on workability in the step of filling the cell with the 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 the N" phase is exhibited, or (2) N" Each has unique properties, such as those that tend to narrow the temperature range in which they exhibit a phase. S0 of the present invention
2. In order to adjust the temperature range in which the N" phase of the liquid crystal composition is exhibited to the above-mentioned preferred range, in the case of (1), an SC base liquid crystal having a narrow temperature range in which the N phase is exhibited, or an SC which does not exhibit an N phase.
A base liquid crystal may be used, and in the case of (2), an SC base liquid crystal that exhibits an N phase over a wide temperature range may be used. This method can be applied not only to the N'' phase but also to the SA phase and the SC'' phase. For example, the chiral dopant expands only the SA phase of the S01 liquid crystal composition, and the N'' phase and S
In the case of reducing the 09 phase, the SC host liquid crystal should have a high upper limit temperature for the SC phase, a wide temperature range for the N phase, and a phase sequence of SC phase → N phase → I phase, or S
It is sufficient to use a material having a narrow temperature range of A phase and a phase sequence of SC phase→SA phase→N phase→I phase.

This tendency of the chiral dopant can be easily determined by measuring the change in phase transition temperature of the SC liquid crystal composition obtained by adding a certain amount of the chiral dopant to the SC matrix liquid crystal. From the results, the temperature range in which each phase in the SC" liquid crystal composition exhibits, particularly the N1 phase, can be easily adjusted.

The chiral dopant used in the present invention is added to a certain amount of SA host liquid crystal.

It is necessary to induce a certain degree of voluntary decentralization (hereinafter abbreviated as P).

As mentioned above, for the SC* liquid crystal composition, the amount of the chiral dopant to be added may be adjusted so that the value of P is in the range of 3 to 30 nC/cm, especially near room temperature. When the value of P induced by is small, the amount added is large relative to the SC base liquid crystal, and the viscosity of the S00 liquid crystal composition increases accordingly, resulting in a high-speed response. Therefore, the chiral dopant used in the present invention is preferably one that can induce P5 of 1.OnC/cm2 or more when added to the SC base liquid crystal in an amount of 10% by weight, and 5% by weight. 0.5nC/c when added
Particularly preferred is one that can induce Ps of m'' 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 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 compound of the above formula (1-a-1) as a medium temperature range host liquid crystal,
An SC matrix liquid crystal (A) was prepared using the compound of the formula (II-a-6) as a viscosity-reducing liquid crystal in the following proportions.

(I-a-1) (II-a-6) Next, when added to the SC base liquid crystal as a chiral dopant to form an SC* liquid crystal composition, as a compound that causes a right-handed helix to appear in the N1 phase. , the compound of formula (VI-6) (this compound is added at 10% to the base liquid crystal (A)), and the helical pitch to appear in the N'' phase at 60°C is 4.
It is 7 μm. ) is 73%, and the pitch of the helix that appears in the N'' phase is 73%, and the compound of the formula (Vl-14) is used as a compound that causes the appearance of a left-handed helix. , 11.9 at 60°C
It is μm. ) was mixed at 27% to prepare a composition in which the helical pitch appearing in the N9 phase was adjusted. The spontaneous polarization value of the SC9 liquid crystal composition consisting of 10% of this chiral dopant and 90% of the SC base liquid crystal (A) at 25° C. was 5.5 nC/cm 2 .

This chiral dopant 16% and the above parent liquid crystal (A) 84
A SC0 liquid crystal composition consisting of %.

The melting point of this SC0 liquid crystal composition was 9"C, showing an SC phase up to 50.0°C, an SA phase up to 60°C, and an NI phase up to 62.5°C, and became one phase at 62.5°C or above.

The helical pitch of this composition at 60.2°C is 30 μm
When it was filled into an orientation-treated cell and slowly cooled from an isotropic liquid phase, it showed good orientation.

In addition, this cell has an electric field strength of 10 Vp-r/μm at 50
When a Hz rectangular wave was applied and the electro-optical response speed was measured, a high-speed response of 42 μsec at 25°C was confirmed.

The spontaneous polarization at this time is 10.9 nC/c+n”,
The tilt angle was 22.3'.

〔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)

[Scope of Claims] 1. (1) (a) An optically inactive liquid crystal compound having a two-ring structure and exhibiting a smectic C phase, or (b)
) A liquid crystal composition consisting of homologues that differ only in the number of carbon atoms or the shape of their alkyl chains, in which at least one compound among the homologs has a temperature range of at least 1 degree at a temperature of 10 degrees Celsius or higher. (2) a liquid crystal composition containing an optically inactive liquid crystal compound having a two-ring structure; A viscosity-reducing liquid that does not exhibit a smectic C phase when used alone, including homologs that differ only in the number of carbon atoms and shape of the alkyl chain, has at least one side chain as an alkyl group, and has one or less ester bond in the molecule. A liquid crystal composition exhibiting a smectic C phase containing
(3) A ferroelectric liquid crystal composition made by adding a chiral dopant, where the chiral dopant has the general formula (A) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, R^1 is the number of carbon atoms 2] ~10 alkyl group, R^2 represents an alkyl group having 1 to 10 carbon atoms, and Z^a represents -O- or -COO-. C^* and C^*^* are each independently (R) configuration or (
S) represents an asymmetric carbon atom in the configuration. X is 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, ▲ Mathematical formula, chemical formula, table, etc. There are ▼, ▲mathematical formulas, etc.
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 It represents a ring, and any one or two -CH= in the ring may be substituted with -N= or -C=, and any one or more -CH= in the ring may be substituted with -N= or -C=.
~2 -CH_2- are -O-, -S-, -NH-,
▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas, chemical formulas,
There are tables, etc. ▼ may be substituted, and any one or two ▲ in the ring may be substituted with ▼ Numerical formulas, chemical formulas, tables, etc.
may be replaced with ▲, which is a mathematical formula, chemical formula, table, etc. Y^1 represents a fluorine atom, a chlorine atom, a cyano group, a methyl group, a methoxy group, and Z^1, Z^2 or Z^
3 each independently represents 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. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or -CH=CH-
represents, Z^4 is -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. ) represents the central skeleton (core) part of a liquid crystal molecule. ] A ferroelectric liquid crystal composition exhibiting a chiral smectic C phase in a wide temperature range including room temperature, which is characterized by containing an optically active compound represented by the following. 2.X is a general formula (E) ▲There are mathematical formulas, chemical formulas, tables, etc.▼
There are chemical formulas, tables, etc. ▼ and ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ are each independently ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲
There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼
, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and Y^
2 and Y^3 each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, or a cyano group, but Y^2 and Y^3 do not represent a hydrogen atom at the same time. Z^1, Z^2 and m
represents the same thing as described in claim 1. 2. The ferroelectric liquid crystal composition according to claim 1, wherein the central skeleton (core) portion is represented by: ). 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.