JPH02269795A - Ferroelectric liquid crystal composition - Google Patents

Abstract

PURPOSE:To obtain the title composition improved in high-speed response characteristics and orientation properties by incorporating a chiral dopant into a liquid crystal composition containing an intermediate-temperature liquid crystal and a specified high-temperature liquid crystal and showing a smectic C phase. CONSTITUTION:An intermediate-temperature liquid crystal (i) comprising, e.g. an optically inactive bicyclic compound showing a smectic C phase (SC phase) is mixed with a high- temperature liquid crystal (ii) containing a compound of formula I (wherein R<a> and R<b> are each 1-18C straight-chain or branched alkyl or alkoxyl; V is -COO- or -OCO-; the group of formula II is any one of groups of formulas III, IV, etc., the group of formula V is a group of formula III or VI, and the group of formula VII is a group of formula III, IV or VI, provided that at least one of the groups of formulas II, V, and VII is a group of formula III or IV) to give a liquid crystal composition showing an SC phase. This liquid crystal composition is mixed with a chiral dopant (iii) containing an optically active compound of formula VIII (wherein Q<1>* and Q<2>* are each an optically active group different from each other and having at least one asymmetric carbon atom, and at least one of them has a structure wherein the asymmetric carbon atoms are directly attached to O, S, N, etc.; Z is the central skeleton part of a liquid-crystal molecule, shown by formula IX: the groups of formulas X, XI, and XII are each a group of formula III, etc.; Y<1> and Y<2> are each a single bond, -COO-, etc.; m is 0 to 1).

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 bistability, it can retain the display even when the power is turned off (memory effect). For this reason, it has great potential to be used in optical shutters, printer heads, flat-screen televisions, etc., and research and development is currently being conducted in various fields to put it into practical use.

The liquid crystal phase of ferroelectric liquid crystals belongs to the tilted chiral smectic phase, and among these, the one that is practically desirable is the chiral smectic C (hereinafter abbreviated as S08) phase, which has the lowest viscosity. It is called.

[Problem to be solved by the invention]

Liquid crystal compounds exhibiting the S01 phase (hereinafter referred to as SC "compounds") have been studied and many compounds have already been synthesized.
One compound alone must meet the following conditions for use as an optical switching element for ferroelectric liquid crystal displays: (a) exhibiting ferroelectricity over a wide temperature range including room temperature; and (b) having appropriate phase stability in a high temperature range. Having a series (c) Particularly chiral nematic (hereinafter abbreviated as N1).

) 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, the current situation is that liquid crystal compositions exhibiting the S00 phase (hereinafter referred to as S01 liquid crystal compositions) are 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 N0 phase in the high temperature range of the SC1 phase, it is generally effective to increase the length of the helical pitch of the N'' phase. *Orientation is better when the smectic A (hereinafter abbreviated as SA) phase is present in the temperature range between the N0 phase and the N0 phase, and in order to increase the helical pitch, an optically active substance that produces left-handed helix and 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)). (It is already a known technique to adjust the orientation.) However, although these techniques can provide good orientation, they do not necessarily provide high-speed response.

In order to exhibit high-speed responsiveness, low-viscosity smectic C (hereinafter abbreviated as SC) is used, for example, as shown in the special lecture at the 12th Liquid Crystal Conference (Proceedings of the same conference P, 9B). An excellent method is to add an SC1 compound having a large spontaneous polarization (hereinafter abbreviated as P) to a parent liquid crystal composition exhibiting a ) phase (hereinafter referred to as SC parent liquid crystal). 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.

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

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

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

[Means to solve the problem]

In order to solve the above problems, the present invention provides a liquid crystal composition (
Hereinafter, it will be referred to as the SC matrix liquid crystal used in the present invention. ), to which a chiral dopant consisting of an optically active compound is added, the high-temperature liquid crystal containing at least one compound represented by the following general formula (A); Provided is a ferroelectric liquid crystal composition exhibiting an S08 phase over a wide temperature range including the present invention.

In the formula, R'' and R' each independently have 1 to 18 carbon atoms.
represents a linear or branched alkyl group or alkoxyl group, where R'' and Rh each independently have 3 to 3 carbon atoms.
It is preferable that at least one of the 12 alkyl groups or alkoxyl groups is a linear alkyl group or alkoxyl group, and it is particularly preferable that at least one of R1 and Rb is an alkyl group.

I was, ■Has -COO- or 10C0 represents.

÷ represents, but When is an alkyl group, Shikaku, R& When is an alkoxyl group, Yes.

In addition, when ■ is COO-, it is true, and when ■ is CO, the SC host liquid crystal used in the present invention has (i) I (isotropic (liquid) having a phase sequence of phase → N phase → SA phase → SC phase (b) having a phase sequence of r phase → SA phase → SC phase (c) having a phase sequence of I phase → N phase → SC phase or (d) a phase sequence of {circle around (2)} phase → SC phase.The selection of (a) to (d) depends 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 the smectic A property of the chiral dopant (when added to the SC matrix liquid crystal, the S
If there is a strong tendency to widen the temperature range of the A phase and narrow the temperature range of the N0 phase, select (c), or if the SC property is weak and the temperature range of the N0 and SA phases tends to be widened. It is most appropriate to use (d). What is important is the phase series in the case of a sc" liquid crystal composition, and for boat fishing, the phase series of 1→N"→5A-3C" is advantageous in terms of orientation. On the other hand, , ■-+N*→S01 may also exhibit better alignment depending on the orientation control method, and a large tilt angle can be easily obtained, so it is suitable for the guest-host system.

The SC base liquid crystal used in the present invention is a composition (■) consisting of a compound that has a two-ring structure and exhibits an SC phase at a temperature close to room temperature, or a homolog thereof (a compound that differs only in the alkyl chain).
Hereinafter, it will be referred to as medium temperature range liquid crystal. ), in order to increase the upper limit temperature of the SC phase, (If) a compound having a high TC point (representing the upper limit temperature of the SC phase or S00 phase) and having a ring structure of 3 or more rings or a homologue thereof This is a composition formed by adding a composition (hereinafter referred to as high temperature liquid crystal).

The medium-temperature liquid crystal used in the present invention is one in which 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 in the homologues has a
It is a compound that exhibits an SC phase, which may be monotropic, in a temperature range of C or higher.

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

(I-a) (I-a-23) R, docOR2 (1-a-24) R10(Ku(warm 0COR2 (1-a-27) KoR with RICoo.

-N (I-a-29) R,0CO((Bo4hama ORz -N (1-a-54) (l a-55) R,0CO (G◎ song) R,0CO-f9 mowing 40R2 (1-a R, ocori Hshi0CORt (1-a-57) R, OCO interrogation C0OR.

(1-b) (1-b-15) (1-b-16) (I-b-17) (I-b-18) (1-b-19) (1-b-20) (1-b-21) (I-b-22) RI +C00 tatami ocoRz R, +coo4ocORt R, 0 meeting 000 (tears 0 COlh R, 0 coo ÷ 0 COR.

R, 0C00 (wet 0COR.

R, COO ÷ coo foot 0 CORz R, COO over-coo meeting 0CORz R, coo+coo (Waki OCORz (I C) (1-c 0-@-COO (tears C0OR.

(1-c R90(shiC00(toRZ) (1-c-8) R+0+C00+ORz (I-c-10) R80-@-COO (Sawa C00Rz (I-c-12) RIO-@-Coo cocoRz (,I-d) (I-d-7) (1-d-8) (1-d-9) (1-d-10) (1-d-11) (1-d-12) (I-d-13) (1-d-14) R, O+C00 (tocoSR.

R, 0C00 (C03R.

R10+C03 (Sawa COO1h R10 (anti-cos(tocol?z) R,0+COO%5Rt R, 0 coo÷SR.

R10+C03 (pregnancy R2 R,S-(Block C00(Tear OR.

(1-e) (I-f) 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 (I-a-1), the formula (1-a-2), and the formula (I-a-
5), formula (1-a-6), formula (1-a-41), formula (I
-a-42) and compounds represented by formula (1-b-1) are particularly preferred.

The high-temperature liquid crystal used in the present invention is an optically inactive compound having a three- or four-ring structure, or a composition thereof, and each compound is an S
The upper limit temperature of C phase (hereinafter abbreviated as Tc) is 50 to 6
When mixed with 10% of the composition at 0°C, its Tc is 1.
Preferably, at least two rings are aromatic rings (1,4-phenylene, pyrimidine-
2,5-diyl, pyrazine-2,5-diyl, pyridine-2,5-diyl, or a fluorine-substituted product thereof), Tc is 90°C or higher, and the temperature range of the SC phase is 5°C.
or a homologue having a different temperature range in the above-mentioned temperature range, or a homologue having a different number of carbon atoms or shape of the alkyl group in the side chain, in particular, at least one component of the compound represented by the general formula (A) It is characterized by containing as follows.

Specific examples of the compound represented by the general formula (A) include the following compounds represented by 2, and the phase transition temperatures of some representative compounds are also shown.

嬶国くQ ヱ= くくくψψME2− MEME嬶In the above, Cr is the crystalline phase, SA is the smectic A phase, and SB
is smectic B phase, SC is smectic C phase, SF is smectic F phase, SG is smectic C phase, SH is smectic H phase, S and S' are smectic phases of unknown origin, N is nematic phase, I is isotropic Each represents a liquid phase.

Among the compounds represented by the general formula (A), -i formula (A-
1), (A-2), (-A-3), (A-4), (A
-5), (A-6), (A-7), (A-8), (A-
11), (A-13), (A-14), (A-15),
(A-16), (A-20), (A-21), (A-2
2), (A-23), (A-24), and (A-26
) are preferred.

As the high temperature liquid crystal, a compound represented by the following general formula (D) can be used in combination with a compound represented by the above general formula (A).

In the formula, R' and R1 each independently have 1 to 18 carbon atoms.
represents a linear or branched alkyl group, Xl and X
2 are each independently -o-, -co.

-oco-, -s-, or a single bond, Zl and 2
1 is each independently -coo-, -oco-, -c)I
, o-0CHz, COS, SCO, C
11z-CHz--C=C-, or a single bond, and represents a hydrogen atom substituted with a fluorine atom, preferably,
At least one of XI and X2 is a single bond substituted with a fluorine atom), and in the SC base liquid crystal containing at least the above-mentioned medium-temperature liquid crystal and high-temperature liquid crystal, the blending ratio of the medium-temperature liquid crystal is 1 to 95% by weight. % is preferable, 40-90
Particularly preferred is 4% by weight.

In the high temperature liquid crystal, the compound represented by the above general formula (A) is 1
It is preferably contained in an amount of 0% by weight or more, particularly 30% by weight or more.

The chiral dopants used in the present invention include (1)
It is possible to use a compound that exhibits a S C'' phase, (2) a compound that exhibits only a liquid crystal phase other than the S C'' phase, or (3) a compound that does not exhibit liquid crystallinity at all; however, in the case of (3),
In order to prevent the tendency for the liquid crystallinity of the SC0 liquid crystal composition obtained by adding it to the C matrix 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 the chiral dopant brings to the S00 liquid crystal composition, the important ones are the helical pitch it induces, the direction of spontaneous decentralization, and its size, which are dependent on the optically active site of each compound constituting the chiral dopant. most affected by

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.

ノ(KV-8> CH3 -O+C11,-)-CH-R3 (IV-9) 0 CH3 111゜-C-Of CL-+-1-Ct(~R1(IV-12
) CH3 -CHRa (IV-13) CH3 -CHrCHCL 0Rs (IV-14) CH.

-CHCHz ORs (rV-20) Hz CH,CH3 C)I-CH2CHzCHz-CHCIl(IV-21
) C1+, 1 -5 + CH2+T-CH (Cllz square 1-CIl.

(IV-32) CH3 -0-CIl-R.

(iv　-Jb) 0-1; H-C1l□-C11 OR.

(IV-53) C.I.

-CH-0-Rs (IV-55) 0 Hz C1 (Rs (IV-57) 0 Hz CHRs (■ C.F.

1・ -0-CI-Rs (IV-71) CH3 0CHCHt　OCORs (IV-83) CH□CN j・ -C00-CI□-CIl-R5 (IV-84) 10 HzCN j* CH, -CI(-R.

CH3 CH8 In each of the above general formulas, m represents an integer of 1 to 4;
n represents an integer of 1 to 10, and R1 has 3 to 8 carbon atoms.
R4 represents an alkyl group having 2 to 10 carbon atoms, R1 represents an alkyl group having 1 to 10 carbon atoms, and R6 represents an alkyl group having 1 to 4 carbon atoms.

In optically active compounds containing only optically active groups represented by formulas (IV-1) to (■-22) as optically active groups, when added to an SC matrix liquid crystal to form an sc'' liquid crystal composition, Most of the spontaneous polarizations are small, and even when the SC* phase is exhibited alone, most of them are only 10 nC/cn+'' or less.

On the other hand, as optically active groups, formulas (IV-31) to (■-9
Many of the optically active compounds containing the optically active group represented by 1) induce a large spontaneous polarization when added to an SC base liquid crystal to form an S00 liquid crystal composition, and when used alone, they induce a large amount of spontaneous polarization.
In some cases, such as when exhibiting a phase, a large value of 300 nC/cm'' or more exists.

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

(V-60) -Moxibustion (V-84) 1■()...-〇(V-108) ◇) oco -0 be now (V Sumioki COi now X Shiba (V-156) min 0CHz g (V-180) Fu It is also possible to use basic skeletons in which a benzene ring or a cyclohexane ring is substituted with a fluorine atom, chlorine atom, bromine atom, methyl group, methoxy group, cyano group, or nitro group.

/ / An optically active compound having the chiral group bonded to one or both sides of the basic skeleton as described above can be effectively used as a constituent component of a chiral dopant. In particular, the general formula (B) in which the chiral groups are bonded to both sides Qlo Z Ql- [wherein, Ql'' and Q20 are mutually different optically active groups, and each optically active group has a small number (both one asymmetric has a carbon atom, and at least one of Q 1m and Q''
The first group has a structure in which an asymmetric carbon atom is directly bonded to oxygen, iodine, nitrogen, fluorine, chlorine, -C- or -CEN. Z represents a structure in which any one or two hydrogen atoms on these rings are substituted with a fluorine atom or a cyano group, but in a structure in which the above hydrogen atoms are substituted with a fluorine atom or a cyano group, Yl and Y2 are each independently a single bond, -COO-0CO
C1h0 0CHt CHzCI(z--c
= c --cos- or -5CO-, but a single bond, -COO--0CO--CIl□〇- or -0C
It is preferable that R2-, and when m=1, Yl
It is preferable that at least one of Y2 and Y2 is a single bond. ] The optically active compound represented by these is preferable.

In the optically active compound represented by general formula (B), in particular, at least one optically active group is represented by the above (rV-31).
It is desirable that it be any of the groups represented by -(■-91).

As described above, the following points can be cited as advantages of using an optically active compound in which different chiral groups are bonded to both sides of the basic skeleton.

(1) It can exhibit stronger spontaneous polarization than a compound having a chiral group on only one side.

That is, a chiral group selected from the groups represented by (IV-31) to (IV-91) above and (IV-1) to (■-22
) A compound having a chiral group selected from the groups represented by (IV-31) to (■-91) on both sides of the basic skeleton, and a compound having the same basic skeleton with chiral groups selected from the groups represented by (IV-31) to (■-91). Compounds with only one group and an achiral group on the other side are added to the SC matrix liquid crystal, and when the spontaneous polarization is determined as an extrapolated value, the compound with chiral groups on both sides has a higher value of 1O~30nC/ cIII2 or larger, the spontaneous polarization derived from the groups represented by (IV-1) to (IV-22) is at most about 10 nC/cm2, so it is larger than the simple sum of the spontaneous polarizations due to the chiral groups on both sides. You can see that

Furthermore, in a compound that is a group selected from the groups represented by (IV-31) to (IV-91) and has different chiral groups on both sides of the basic skeleton, the spontaneous polarization due to both chiral groups is Polar ((S)-2-methylbutyl b-decyloxybenzylidene aminophenyl cinnamate (DOBAMBC), a well-known ferroelectric liquid crystal)
The polarity of is determined as θ. ), a very large spontaneous polarization can be obtained.

In this case, a larger spontaneous polarization of 100 nC7cm'' or more can be obtained than the simple sum of the spontaneous polarizations due to the chiral groups on both sides.

As a chiral dopant, the larger the spontaneous polarization it can induce, the smaller its amount needs to be used.
The proportion of C matrix liquid crystal can be increased, and as a result, S
01 It is possible to lower the viscosity of the liquid crystal composition. as a result,
This leads to improved responsiveness.

(2) It is possible to adjust the helical pitch, such as in compounds with very long helical pitches and compounds with very short helical pitches induced in the N'' phase or S01 phase.

As mentioned above, in order to obtain good orientation, it is important that the helical pitch of the N" phase or S09 phase is long. It is sufficient that the helical pitch of the chiral dopant is adjusted as a whole. Although this is not necessarily the case for individual compounds, it is easier to adjust the helical pitch if the main component of the chiral dopant has a somewhat longer helical pitch.Furthermore, for compounds added with the main purpose of adjusting the helical pitch, The shorter the helical pitch is, the more advantageous it is because the amount added can be suppressed.

In order to lengthen the helical pitch, the directions of the helical pitch due to the chiral groups on both sides should be opposite to each other, but (IV-31
) to (It/-91), it is preferable that the polarities of the spontaneous polarization are the same in a compound having groups on both sides selected from the groups represented by (It/-91).

(3) Particularly (IV-31) ~ which can show large spontaneous polarization
Chiral groups selected from the groups represented by (IV-91) obtained by chemical methods such as asymmetric synthesis and optical resolution often do not have 100% optical purity; It is quite difficult to purify these to 100%. However, (S) obtained from natural products
When combined with chiral groups derived from -2-methylbutanol or chiral groups with high optical purity such as those obtained by microbial engineering techniques, these become diastereomers, which can be separated by chromatography or recrystallization. This makes it easy to achieve optical purity close to 100%.

It is effective to use the compound of general formula (B) in an amount of 10% or more, preferably 30% or more, particularly preferably 50% or more as a constituent component of the chiral dopant.

-a Among the compounds of formula (B), compounds having particularly preferable combinations of basic skeleton and chiral group are shown below.

LVI E) ht-L; II-Y-Otsu10-L; I'IZL; tl Ks In the above general formula, R4 and R4' each independently represent an alkyl group having 2 to 10 carbon atoms, and R7 and R and / each independently represent an alkyl group having 1 to 10 carbon atoms,
R9 is a linear alkyl group having 2 to 10 carbon atoms, a branched alkyl group having 3 to 10 carbon atoms, or an optically active group having at least one asymmetric carbon having 4 to 10 carbon atoms. represents an alkyl group, l represents an integer of 0 to 5,
Y is a single bond, -o-, -oco-, -coo-, or -
oco.

, W represents chlorine fluorine or -0 Clb, and Z' is COO- OCO- -CH,0- 10CH2-.

or simple vinegar.

Xl and X4 each independently represent a hydrogen atom, a fluorine atom or a cyano group, X2 represents a hydrogen atom or Xl,
X3 represents a hydrogen atom or X4, and at least one of X4 represents a hydrogen atom.

The above chiral dopant is present in the SC matrix liquid crystal at 1 to 60%.
It is appropriate to add it in a proportion of 2% by weight and use it as an S08 liquid crystal composition, but it is more preferable to add it in a proportion of 2 to 50% by weight. When the addition ratio of the chiral dopant 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, 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 and thereby 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 SC0 liquid crystal composition is 3 to 30 nC/c
III! 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% by weight.
In the case of a chiral dopant that exhibits strong spontaneous polarization of nC7cm" or more, the addition ratio of the chiral dopant is preferably in the range of 2 to 25%. The stronger the spontaneous polarization induced by the chiral dopant, the more desirable the addition ratio. However, in the chiral dopant made of the exemplified optically active compound, the addition ratio does not fall below 1% by weight.

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

Among the optically active compounds of general formula (B), in compounds where the directions of the helices induced in the N'' phase by the chiral groups R1'' + R1* on both sides are opposite to each other, the induced helical pitch is quite long. Therefore, when using such a 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 as follows. It can be adjusted for a long time.

The helical pitch P (lIm) appearing in the N* phase of an sc* liquid crystal composition containing multiple optically active compounds is defined as C# for the concentration of each optically active substance, and P for the helical pitch per unit concentration of each optically active substance.
i (μm) (Here, the right-handed spiral pitch is positive and the left-handed spiral pitch is negative), and using this, S
P direct at 5A-N'' point T0 of C4 liquid crystal composition is PT
When l, C4 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 inferred 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. The estimated value T 0/ and the To of the composition selected using it are thick (ll'l if different)
What is necessary is to perform the measurement again using To instead of 01.

The temperature range in which the SC "liquid crystal composition of the present invention exhibits the N'" phase is preferably 3 degrees or more and less than 30 degrees.

If the temperature range in which the N* phase is exhibited is less than 3 degrees, it is not preferable because the phase transition to the SA phase occurs immediately when the temperature decreases, making it difficult to fully align liquid crystal molecules in the N'' phase. If the temperature range exhibiting the N'' phase is 30 degrees or higher, the clearing point of the S01 liquid crystal composition becomes high, which tends to have a negative effect on workability in the step of filling the cell with liquid crystal material, etc., which is not preferable.

A chiral dopant is one that tends to expand the temperature range in which (1) the N" phase is exhibited, or Each has unique properties, such as those that tend to narrow the temperature range in which they exhibit a phase. SC of the present invention
In order to adjust the temperature range showing the "N" phase of the liquid crystal composition to the above-mentioned preferred range, in the case of (1), the SC base liquid crystal has a narrow temperature range showing the N phase, or the SC base liquid crystal does not show the N phase.
It is sufficient to use a matrix liquid crystal, and in the case of (2) 1, it is sufficient to use an SC matrix liquid crystal that exhibits an N phase over a wide temperature range. This method can be applied not only to the N1 phase but also to the SA phase and the "sc" phase. For example, the chiral dopant expands only the SA phase of the "SC" liquid crystal composition, and the N0 phase and the SC3 phase. When scaling down the SC phase, the upper limit temperature of the SC phase is high and the temperature range of the N phase is wide.
In addition, it is sufficient to use one having a phase sequence of SC phase→N phase→■ phase, or one having a phase sequence of 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 S08 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.

The chiral dopant used in the present invention is required to induce a certain level of spontaneous polarization (hereinafter abbreviated as P3) by adding it to a certain amount of SC host liquid crystal.

As mentioned above, in the SC* liquid crystal composition, the amount of the chiral dopant added may be adjusted so that the value of P is in the range of 3 to 30 nC/cm2, especially near room temperature. However, when the value of P induced by the chiral dopant 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. Therefore, the chiral dopant used in the present invention has a P content of 1.0 nC/e+m" or more when added to the SC matrix liquid crystal by 10 times %. , is preferable, and when added at 5% by weight, 0.5
Particularly preferred are those that can induce P5 of nC/cm'' 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, "%" represents weight %. The phase transition temperature of the composition can also be measured using a polarizing microscope equipped with a temperature control stage and a differential scanning calorimeter (D
SC) was used in combination.

Example 1 was mixed to prepare a chiral dopant in which the pitch of the helix appearing in the N1 phase was adjusted. This chiral dopant has an SC phase below 51°C and an S phase below 70.5°C.
A phase shows N1 phase below 71.5℃, and its melting point is 31
It was °C.

Next, as a medium temperature range liquid crystal, formula % and formula % were obtained from the compound represented by the general formula (1-al), and formula 8.2% and formula 8 were obtained from the compound represented by the general formula (I-b-1). .2%, 10% of the compound of formula (A-22-1) as a high temperature liquid crystal, and 35% of the chiral dopant.

This 5011 liquid crystal composition exhibits an S00 phase at temperatures below 54°C.
It exhibited an SA phase at 66° C. or lower, an N* phase at 73° C. or lower, and an isotropic liquid (I) phase at higher temperatures.

Moreover, the melting point was -12°C.

The helical pitch of the N* phase of this 5011 liquid crystal composition at 66.5°C is 10 am or more, and this S00 liquid crystal composition is connected to two glass transparent electrodes that have been subjected to alignment treatment (polyimide coating-rubbing treatment). The thickness is about 2
When it was filled into a μm cell and slowly cooled from the ■ phase to room temperature, it showed extremely good orientation and a uniform monodomain was obtained.

When we applied a rectangular wave with an electric field strength of 1Ov□P/μm and 507 to this cell and measured the electro-optic response speed, we found that 2
A high-speed response of 131 μsec at 5°C was confirmed.

The tilt angle at this time is 26.8', and the spontaneous polarization is 10
, 4 nC/cm'', and the contrast was good.

Example 2 In Example 1, the formula (A-22
-1) In place of the compound of the formula (A-23-1), (
A S01 liquid crystal composition was prepared in the same manner as in Example 1 except that each compound of A-7-1) or (A-17-1) was used, a cell was created, and the electro-optical response speed was measured. Ta.

The results are shown below.

Example 3 As a medium temperature range liquid crystal, 25% of the compound represented by the general formula (I-a-1), 25% of the formula from the compound represented by the general formula (1-b-1), A S09 liquid crystal composition was prepared using 20% of the chiral dopant and 14% of each compound of the formula (A-11-1), (A-8-2) or (A-14-1) as the high temperature liquid crystal. Each was prepared. The measurement results of the phase transition temperature, electro-optic response speed and contrast measured in the same manner as in Example 1 of this S01 liquid crystal composition are shown below.

/ / [Effects 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.

teenager Reason Man

Claims (1)

[Claims] 1. Contains medium temperature range liquid crystal and high temperature liquid crystal, smectic C
It is a ferroelectric liquid crystal composition made by adding a chiral dopant consisting of an optically active compound to a liquid crystal composition exhibiting a phase, and the high temperature liquid crystal has the general formula (A) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (Formula inside, R^a and R^b each independently have a carbon atom number of 1
-18 represents a linear or branched alkyl group or alkoxyl group, and V represents -COO- or -OCO-. ▲ 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,
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Or ▲ represents a mathematical formula, chemical formula, table, etc., and ▲ represents a mathematical formula,
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, ▲ 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. ▼ represents ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ means ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼,▲Mathematical formulas, chemical formulas,
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Or ▲There are mathematical formulas, chemical formulas, tables, etc.▼ represents at least ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ and ▲There are mathematical formulas, chemical formulas, tables, etc.▼ One ring represents ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼. ) A ferroelectric liquid crystal composition exhibiting a chiral smectic C phase in a wide temperature range including room temperature. 2. The ferroelectric liquid crystal composition according to claim 1, wherein ▲There are mathematical formulas, chemical formulas, tables, etc.▼ is ▲There are mathematical formulas, chemical formulas, tables, etc.▼. 3. The ferroelectric liquid crystal composition according to claim 1, wherein ▲There are mathematical formulas, chemical formulas, tables, etc.▼ is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and V is -OCO-. 4. The ferroelectric liquid crystal composition according to claim 1, wherein ▲There are mathematical formulas, chemical formulas, tables, etc.▼ is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and V is -OCO-. 5. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, R^a is an alkoxyl group, and V is -OCO
- The ferroelectric liquid crystal composition according to claim 1. 6. The ferroelectric material according to claim 1, wherein ▲There are mathematical formulas, chemical formulas, tables, etc.▼ is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, R^a is an alkyl group, and V is -OCO- liquid crystal composition. 7. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, R^a is an alkoxyl group, and V is -OCO
- The ferroelectric liquid crystal composition according to claim 1. 8. The ferroelectric material according to claim 1, wherein ▲There are mathematical formulas, chemical formulas, tables, etc.▼ is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, R^a is an alkyl group, and V is -COO- liquid crystal composition. 9. The ferroelectric liquid crystal composition according to claim 2, 3, 4, 5, 6, 7, or 8, wherein ▲There are mathematical formulas, chemical formulas, tables, etc.▼ is ▲There are mathematical formulas, chemical formulas, tables, etc.▼. 10. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and R^b is an alkyl group, Claims 2, 3, 4, 5, 6, 7, or 8
The ferroelectric liquid crystal composition described above. 11. The ferroelectric liquid crystal composition according to claim 2, 3 or 8, wherein ▲There are mathematical formulas, chemical formulas, tables, etc.▼ is ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼ thing. 12. The ferroelectric material according to claim 2, 3, 4, 6, or 7, wherein ▲There are mathematical formulas, chemical formulas, tables, etc.▼ is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and R^b is an alkoxyl group. liquid crystal composition. 13. The chiral dopant has the general formula (B) Q^1^*-Z-Q^2^* [In the formula, Q^1^* and Q^2^* are different optically active groups, and each The optically active group has at least one asymmetric carbon atom, and in at least one of Q^1^* and Q^2^*, the asymmetric carbon atom is oxygen, sulfur, nitrogen, or fluorine. , chlorine or ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or has a structure directly connected to -C≡N. Z
is a general formula (C) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas,
There are chemical formulas, tables, etc. ▼ and ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ are each independently ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲
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, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas,
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or represents a structure in which any one or two hydrogen atoms on these rings are substituted with a fluorine atom or a cyano group, and Y^1 and Y^2 each independently represent a single bond, -COO-, -OCO- , -CH_
2O-, -OCH_2-, -CH_2CH_2-, -C
≡C-, -COS- or -SCO-, and m represents 0 or 1. ) represents the central skeleton (core) part of a liquid crystal molecule. ] Claims 1, 2, containing an optically active compound represented by
The ferroelectric liquid crystal composition according to 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12.