JP2007197487A - Liquid crystal composition, liquid crystal element, liquid crystal display element, light control material, and display method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light control material having high light-control capability and small power consumption. <P>SOLUTION: A liquid crystal composition comprises at least one or more smectic liquid crystals capable of being driven by 2 frequencies and at least one polymer material. There are also provided a liquid crystal element comprising the liquid crystal composition, a liquid crystal display element and a light control material comprising the liquid crystal element, and a display method. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technical field of a liquid crystal composition, a liquid crystal element, a liquid crystal display element, a light control material, and a display method.

With the increasing interest in the environment, the importance of materials capable of electrically adjusting the amount of light, so-called electrical light control materials, is increasing. Until now, electrochromic methods using an oxidation-reduction reaction, polymer dispersed liquid crystal (PDLC) methods using a composite system of a liquid crystal and a polymer, and the like have been proposed as electrical light control materials.
However, in the electrochromic method, there is a problem that it is difficult to increase the area by current drive, and there are still problems in durability of the electrochromic dye. Further, in the PDLC method, after the voltage application is stopped, In many cases, the property of maintaining the state, that is, the so-called memory property is poor, and from the viewpoint of power consumption, the provision of the memory property has been demanded.

  Under such circumstances, a light-controlling material having a memory property using a smectic liquid crystal has been proposed (for example, see Non-Patent Document 1). However, in this method, since the dynamic scattering method based on current drive is used, dimming unevenness is likely to occur, there is a concern that durability is low, power consumption at the time of dimming switching is large, large area The problem remains that dimming is difficult.

The same problem remains for the liquid crystal display element, and even in the liquid crystal display element using the smectic liquid crystal described in Non-Patent Document 1, there is a concern that display unevenness is likely to occur and durability is low. There are problems that power consumption is large and display of a large area is difficult.
SID Digest, 35, 1420, 2004

  An object of the present invention is to provide a liquid crystal composition, a liquid crystal element, a liquid crystal display element, a dimming material, and a display method having a memory property and high dimming performance or display performance.

  Therefore, the present invention has been made in view of the above problems, and as a result of extensive research, it has a memory property by combining a specific smectic liquid crystal composition and a polymer material, and is extremely Obtaining knowledge that a liquid crystal composition, a liquid crystal element, a liquid crystal display element, a light control material, and a display method exhibiting high light control performance or display performance can be realized, and further study based on this knowledge to complete the present invention It came.

  Means for solving the above-mentioned problems are as follows.

[1] A liquid crystal composition containing at least one type of smectic liquid crystal capable of being driven at two frequencies and at least one type of polymer material.

[2] The liquid crystal composition according to [1], wherein the smectic liquid crystal exhibits a smectic A phase.

[3] The liquid crystal composition according to [1] or [2], wherein the smectic liquid crystal contains at least one nematic liquid crystal compound.

[4] The liquid crystal composition intermediate comprising at least one monomer and at least one smectic liquid crystal that can be driven at two frequencies is polymerized. It is a liquid-crystal composition of any one.

[5] The liquid crystal composition according to [4], wherein the liquid crystal composition intermediate further contains a polymerization initiator.

[6] The liquid crystal composition according to [4] or [5], wherein the liquid crystal composition intermediate further contains a nematic liquid crystal compound.

[7] The liquid crystal composition according to any one of [1] to [6], further including a color material.

[8] The liquid crystal composition according to [7], wherein the colorant is a dichroic dye.

[9] The liquid crystal composition according to any one of [1] to [8], wherein the smectic liquid crystal contains a smectic liquid crystal compound represented by the following general formula (1). .

Formula ^{(1): T 1 - {} (D 1) e -L 1} m - (D 2) k -T 2

In the formula, D ¹ and D ² each independently represent an arylene group, heteroarylene group or divalent cyclic aliphatic hydrocarbon group, L ¹ represents a divalent linking group, and T ¹ and T ² each independently Represents an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an acyl group, an acyloxy group, a halogen atom or a cyano group, e represents a number of 0 to 5, and m represents a number of 1 to 3, respectively. , K represents a number from ¹ to ² , the total number of groups represented by D ¹ and D ² is a number from 3 to 5, and when e and k are each 2 or more, 2 or more D ¹ and D ² May be the same or different, and when m is 2 or more, two or more {(D ¹ ) _e -L ¹ } may be the same or different.

[10] A liquid crystal element comprising a laminate including an electrode and a liquid crystal layer including the liquid crystal composition according to any one of [1] to [9] provided between the electrodes. is there.

[11] The liquid crystal element according to [10], wherein the electrode is a transparent electrode made of ITO (indium tin oxide).

[12] A display method characterized in that the display is switched by driving the liquid crystal element according to [10] or [11] with an alternating voltage of a high frequency and a low frequency.

[13] A liquid crystal display element comprising a pair of substrates, the liquid crystal device according to [10] or [11] being provided between the substrates, and a quantity of reflected light of incident light being changed.

[14] The liquid crystal display element according to [13], wherein a colored layer is provided on a surface side of the substrate on which the liquid crystal element is not provided.

[15] The liquid crystal display element according to [13] or [14], wherein the base is formed of a polymer.

[16] The liquid crystal display element according to any one of [13] to [15], which has an antireflection film.

[17] The liquid crystal display element according to [16], wherein the antireflection film is provided on a surface of the support.

[18] The liquid crystal display element according to [16], wherein the antireflection film is attached to an electrode surface.

[19] The liquid crystal display element according to any one of [16] to [18], wherein the antireflection film is an inorganic thin film, an organic thin film, or an inorganic-organic composite film.

[20] The liquid crystal display element according to any one of [13] to [19], further including a barrier layer.

[21] The liquid crystal display element according to any one of [13] to [20], further including an ultraviolet absorbing layer.

[22] A light-modulating material comprising a pair of bases, the liquid crystal element according to [10] or [11] provided between the bases, and changing the transmittance of incident light.

[23] The light control material according to [22], wherein a colored layer is provided on a surface side of the substrate on which the liquid crystal element is not provided.

[24] The light control material according to [22] or [23], wherein the substrate is a polymer support.

[25] The light control material according to any one of [22] to [24], which has an antireflection film.

[26] The light control material according to [25], wherein the antireflection film is attached to a surface of the support.

[27] The light control material according to [25], wherein the antireflection film is attached to an electrode surface.

[28] The light control material according to any one of [25] to [27], wherein the antireflection film is an inorganic thin film, an organic thin film, or an inorganic-organic composite film.

[29] The light control material according to any one of [22] to [28], which includes a barrier layer.

[30] The light control material according to any one of [22] to [29], which has an ultraviolet absorbing layer.

  According to the present invention, it is possible to provide a liquid crystal composition, a liquid crystal element, a liquid crystal display element, a light control material, and a display method that have a memory property and exhibit high display performance or light control performance.

  Hereinafter, the present invention will be described in detail. In the present specification, “to” indicates a range including the numerical values described before and after the minimum and maximum values, respectively.

  The liquid crystal composition of the present invention contains at least one smectic liquid crystal capable of being driven at two frequencies and at least one polymer material.

The smectic liquid crystal usable in the present invention exhibits a so-called dual-frequency drivability in which the dielectric anisotropy with respect to a low frequency voltage is positive and the dielectric anisotropy with respect to a high frequency voltage is negative.
By using the dual frequency drive liquid crystal, the alignment can be controlled by changing the frequency, so that an alignment film becomes unnecessary. As a result, the element configuration becomes simple and the manufacturing process can be simplified. Further, when there is no alignment film, display performance is improved because there is no light absorption or reflection by the alignment film. Therefore, a high reflectance is given in the reflective display.

Here, a driving method using the dual-frequency driving liquid crystal will be described. The dual-frequency driving liquid crystal has a positive dielectric anisotropy with respect to a low frequency voltage and a negative dielectric anisotropy with respect to a high frequency voltage. First, when a low-frequency voltage is applied to the liquid crystal, the liquid crystal molecules are aligned parallel to the direction of the electric field because the dielectric anisotropy of the liquid crystal is positive. That is, the liquid crystal molecules are aligned perpendicular to the substrate with electrodes. Next, when a high frequency voltage is applied to the liquid crystal, the liquid crystal molecules are aligned perpendicular to the direction of the electric field because the dielectric anisotropy of the liquid crystal is negative. That is, the liquid crystal molecules are aligned horizontally with respect to the substrate with the electrodes. Therefore, it is possible to switch the alignment state of the liquid crystal molecules by switching between a low frequency voltage and a high frequency voltage.
That is, a stable alignment state can be maintained in any state of the alignment state perpendicular to and parallel to the substrate.

  In addition, by using a smectic liquid crystal, memory properties can be imparted to a liquid crystal composition, a liquid crystal element, a liquid crystal display element, and a light control material.

  Furthermore, the liquid crystal composition used in the light control material and the liquid crystal display element of the present invention contains at least one polymer material. The principle of switching between the scattering state and the transparent state in the light modulating material and the liquid crystal display element of the present invention will be described.

First, when the refractive index (n‖) in the major axis direction of the liquid crystal molecules is matched as much as possible with the refractive index (n _p ) of the polymer material, the liquid crystal molecules are aligned in a state perpendicular to the electrode substrate. In addition, the refractive index difference between the liquid crystal composition and the polymer material becomes small, and light is transmitted without being scattered. That is, it becomes transparent.
The refractive index anisotropy (Δn) is a difference between the refractive index (n‖) in the major axis direction of the liquid crystal molecule and the refractive index (n⊥) in the minor axis direction of the liquid crystal molecule, as represented by the following formula. Is defined as
Δn = n‖−n⊥

Here, when the host liquid crystal is aligned in a horizontal state using a host liquid crystal having refractive index anisotropy (that is, Δn is not 0), the refractive index (n⊥) in the minor axis direction of the host liquid crystal Since there is a difference in the refractive index (n _p ) of the polymer material, light is scattered. That is, in order to increase light scattering, it is preferable that the difference between n⊥ and n _p is large, and it is preferable to use a host liquid crystal having a large Δn. Δn of the host liquid crystal is preferably 0.05 or more, more preferably 0.10 or more, and particularly preferably 0.12 or more. A liquid crystal having such a large refractive index anisotropy can be achieved by introducing a polarizing group (for example, a cyano group or a fluorine atom) into the liquid crystal molecule long axis.

The liquid crystal composition used for the light control material and the liquid crystal display element of the present invention is obtained by dispersing the liquid crystal in the polymer material using the polymer material as a medium. That is, in the liquid crystal composition of the present invention, as shown in FIG. 1, the liquid crystal is dispersed in the polymer medium in the form of droplets. Therefore, unlike the case of the liquid crystal layer sandwiched between the substrates, even if an alignment film is provided on the substrate, the alignment of the liquid crystal cannot be adjusted by the alignment film.
However, since the liquid crystal composition of the present invention uses a smectic liquid crystal that can be driven at two frequencies as the liquid crystal, even if it is a droplet liquid crystal, the vertical and parallel alignment states can be stably maintained by changing the frequency. it can. In addition, since a smectic liquid crystal is used, a memory property can be obtained, and a low threshold value and a fast response time can be achieved. In particular, when the smectic liquid crystal exhibits a smectic A phase, the response speed is high due to the low liquid crystal viscosity, and the optical axis in the vertical alignment state is approximately 90 ° with respect to the substrate, and the absorption in the colorless display state is small. Therefore, the contrast ratio is high, which is a preferable mode.

  Hereinafter, the liquid crystal composition, the liquid crystal element, the liquid crystal display element, the light control material, and the display method will be described in detail.

1. Liquid crystal composition The liquid crystal composition of the present invention contains at least one smectic liquid crystal capable of being driven at two frequencies and at least one polymer material.

1-1 Smectic liquid crystal capable of dual-frequency driving The smectic liquid crystal capable of dual-frequency driving usable in the present invention includes (1) a smectic liquid crystal compound capable of dual-frequency driving, and (2) capable of dual-frequency driving. Any of nematic liquid crystal compounds and smectic liquid crystal compounds may be used. However, a smectic liquid crystal compound that can be driven at two frequencies is a crystal at room temperature, has a very high threshold voltage, and has a high viscosity, so that the response speed tends to be slow and the power consumption increases. On the other hand, when a smectic liquid crystal compound is mixed with a nematic liquid crystal compound that can be driven at two frequencies, it becomes easy to control the dielectric characteristics and viscosity, lower the threshold voltage, and shorten the response time. Accordingly, the smectic liquid crystal capable of being driven at the two frequencies described in (2) is preferable.

  The preferred content ratio of the smectic liquid crystal compound and the nematic liquid crystal compound capable of dual-frequency driving in the case of (2) above may be any ratio, but “nematic liquid crystal compound capable of dual-frequency driving: smectic liquid crystal compound” However, 20 mol%: 80 mol% to 99 mol%: 1 mol% is preferable, 50 mol%: 50 mol% to 95 mol%: 5 mol% is more preferable, and 70 mol%: 30 mol% to 90 mol%: 10 mol% is still more preferable. When the ratio of the smectic liquid crystal compound is more than 80 mol% with respect to 20 mol% of the nematic liquid crystal compound that can be driven at two frequencies, the liquid crystal phase is not taken at room temperature, or the viscosity becomes high. In addition, when the ratio of the smectic liquid crystal compound is less than 1 mol% with respect to 99 mol% of the nematic liquid crystal compound that can be driven at two frequencies, the smectic A phase may not be expressed in many cases, which is not preferable.

(1) Nematic liquid crystal compound that can be driven at two frequencies A so-called nematic liquid crystal that can be driven at two frequencies and has a positive dielectric anisotropy for a low frequency voltage and a negative dielectric anisotropy for a high frequency voltage. The compounds are detailed in Japan Society for the Promotion of Science 142nd Committee, Liquid Crystal Device Handbook, Nikkan Kogyo Shimbun, 1989, pages 189-192. As a specific example thereof, a dual frequency driving nematic liquid crystal compound manufactured by Eastman Kodak Company is shown below.

  In addition, examples of commercially available dual-frequency drive liquid crystal materials include DF-02XX, DF-05XX, FX-1001, FX-1002, and MLC-2048 manufactured by Merck.

  In the present invention, particularly suitable nematic liquid crystal compounds that can be driven at two frequencies include smectic liquid crystal compounds that can be driven at two frequencies, and may have an approximate refractive index, crossover frequency, phase transition temperature, and viscosity. preferable. Moreover, it is preferable that the polymer material to be used also has physical properties approximate to the refractive index, crossover frequency, phase transition temperature, and viscosity of the smectic liquid crystal compound that can be driven at two frequencies used in the present invention.

(2) Smectic liquid crystal compound capable of dual frequency driving The smectic liquid crystal compound capable of dual frequency driving is described in detail in Mol. Cryst. Liq. Cryst., Vol. 49, 83-87 (1978). In the present invention, this description can be applied as appropriate.

(3) Smectic liquid crystal compound The smectic liquid crystal compound that can be used in combination with a nematic liquid crystal compound that can be driven at two frequencies is not particularly limited as long as it is a liquid crystal compound that exhibits a smectic phase, but a smectic liquid crystal compound that exhibits a smectic A phase is Since the liquid crystal viscosity is low, the response speed is fast, and the optical axis in the vertical alignment state is approximately 90 ° with respect to the substrate, and the absorption in the colorless display state is small, so that the contrast ratio is high.

As such a liquid crystal compound, a structure represented by the following general formula (1) is particularly preferable.
Formula ^{(1): T 1 - {} (D 1) e -L 1} m - (D 2) k -T 2

In general formula (1), D ¹ and D ² each independently represent an arylene group, a heteroarylene group, or a divalent cyclic aliphatic hydrocarbon group, both of which may or may not have a substituent. Good.

The arylene group represented by D ¹ and D ² is preferably an arylene group having 6 to 20 carbon atoms, more preferably 6 to 10 carbon atoms. Specific examples of the preferred arylene group include a phenylene group and a naphthalene group. Particularly preferred is a substituted phenylene group, and more preferred is a 1,4-phenylene group.

The heteroarylene group represented by D ¹ and D ² is preferably a heteroarylene group having 1 to 20 carbon atoms, more preferably 2 to 9 carbon atoms. Specific examples of preferred heteroarylene groups include pyridine ring, quinoline ring, isoquinoline ring, pyrimidine ring, pyrazine ring, thiophene ring, furan ring, oxazole ring, thiazole ring, imidazole ring, pyrazole ring, oxadiazole ring, thiadiazole ring And a group consisting of a triazole ring and a heteroarylene group obtained by removing one hydrogen each from two carbon atoms of a condensed ring formed by condensing them.

The divalent cycloaliphatic hydrocarbon group represented by D ¹ and D ² is preferably a divalent cycloaliphatic hydrocarbon group having 3 to 20 carbon atoms, more preferably 4 to 10 carbon atoms. Specific examples of preferred divalent cycloaliphatic hydrocarbon groups are cyclohexanediyl and cyclopentanediyl, more preferably cyclohexane-1,2-diyl group, cyclohexane-1,3-diyl group, cyclohexane-1,4. -Diyl group and cyclopentane-1,3-diyl group, particularly preferably (E) -cyclohexane-1, 4-diyl group.

The divalent arylene group, divalent heteroarylene group and divalent cyclic aliphatic hydrocarbon group represented by D ¹ and D ² may have a substituent or may be unsubstituted. In the formula (3), when e, m or k is 2 or more, the plurality of D ¹ and D ² may each independently have a substituent, and have the same substituent. Alternatively, they may have different substituents or may be unsubstituted.
Examples of these substituents include the following substituent group V.

(Substituent group V)
Halogen atom (for example, chlorine, bromine, iodine, fluorine), mercapto group, cyano group, carboxyl group, phosphate group, sulfo group, hydroxy group, 1 to 10 carbon atoms, preferably 2 to 8 carbon atoms, more preferably carbon A carbamoyl group having 2 to 5 carbon atoms (for example, methylcarbamoyl, ethylcarbamoyl, morpholinocarbonyl), a sulfamoyl group having 0 to 10, preferably 2 to 8 carbon atoms, more preferably 2 to 5 carbon atoms (for example, methylsulfamoyl group). Moyl, ethylsulfamoyl, piperidinosulfonyl), a nitro group, an alkoxy group having 1 to 20, preferably 1 to 10, and more preferably 1 to 8 carbon atoms (for example, methoxy, ethoxy, 2-methoxy) Ethoxy, 2-phenylethoxy), 6 to 20 carbon atoms, preferably 6 to 12 carbon atoms More preferably an aryloxy group having 6 to 10 carbon atoms (for example, phenoxy, p-methylphenoxy, p-chlorophenoxy, naphthoxy), 1 to 20 carbon atoms, preferably 2 to 12 carbon atoms, more preferably 2 carbon atoms. 8 acyl groups (for example, acetyl, benzoyl, trichloroacetyl), 1 to 20 carbon atoms, preferably 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms (for example, acetyloxy, benzoyloxy), carbon atoms An acylamino group having 1 to 20, preferably 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms (eg acetylamino), 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to carbon atoms 8 sulfonyl groups (eg methanesulfonyl, ethanesulfonyl, benzenesulfonyl) A sulfinyl group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms (for example, methanesulfinyl, ethanesulfinyl, benzenesulfinyl), 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms And more preferably a substituted or unsubstituted amino group having 1 to 8 carbon atoms (for example, amino, methylamino, dimethylamino, benzylamino, anilino, diphenylamino, 4-methylphenylamino, 4-ethylphenylamino, 3-n -Propylphenylamino, 4-n-propylphenylamino, 3-n-butylphenylamino, 4-n-butylphenylamino, 3-n-pentylphenylamino, 4-n-pentylphenylamino, 3-trifluoromethyl Phenylamino, 4-trifluoromethylphenylamino 2-pyridylamino, 3-pyridylamino, 2-thiazolylamino, 2-oxazolylamino, N, N-methylphenylamino, N, N-ethylphenylamino), 0 to 15 carbon atoms, preferably 3 to 10 carbon atoms More preferably, it is an ammonium group having 3 to 6 carbon atoms (for example, trimethylammonium or triethylammonium), a hydrazino group having 0 to 15, preferably 1 to 10, more preferably 1 to 6 carbon atoms (for example, trimethylhydra). Dino group), ureido group having 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms (for example, ureido group, N, N-dimethylureido group), 1 to 15 carbon atoms, preferably Is an imide group having 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms (for example, a succinimide group). An alkylthio group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms (for example, methylthio, ethylthio, propylthio), 6 to 80 carbon atoms, preferably 6 to 40 carbon atoms, more preferably Is an arylthio group having 6 to 30 carbon atoms (for example, phenylthio, p-methylphenylthio, p-chlorophenylthio, 2-pyridylthio, 1-naphthylthio, 2-naphthylthio, 4-propylcyclohexyl-4′-biphenylthio, 4-butyl. Cyclohexyl-4′-biphenylthio, 4-pentylcyclohexyl-4′-biphenylthio, 4-propylphenyl-2-ethynyl-4′-biphenylthio), 1 to 80 carbon atoms, preferably 1 to 40 carbon atoms, Preferably, the heteroarylthio group having 1 to 30 carbon atoms (for example, 2 Pyridylthio, 3-pyridylthio, 4-pyridylthio, 2-quinolylthio, 2-furylthio, 2-pyrrolylthio), an alkoxycarbonyl group having 2 to 20, preferably 2 to 12, and more preferably 2 to 8 carbon atoms ( Methoxycarbonyl, ethoxycarbonyl, 2-benzyloxycarbonyl), an aryloxycarbonyl group having 6 to 20 carbon atoms, preferably 6 to 12 carbon atoms, more preferably 6 to 10 carbon atoms (for example, phenoxycarbonyl), 1 carbon atom To an unsubstituted alkyl group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, more preferably 1 to 5 carbon atoms (eg methyl, ethyl, propyl, butyl), 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, Preferably a substituted alkyl group having 1 to 5 carbon atoms {eg hydroxymethyl , Trifluoromethyl, benzyl, carboxyethyl, ethoxycarbonylmethyl, acetylaminomethyl, and an unsaturated hydrocarbon group having 2 to 18 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms. For example, a vinyl group, an ethynyl group, a 1-cyclohexenyl group, a benzylidine group, and a benzylidene group) are also included in the substituted alkyl group}, having 6 to 20, preferably 6 to 15, more preferably 6 to 10 carbon atoms. A substituted or unsubstituted aryl group (for example, phenyl, naphthyl, p-carboxyphenyl, p-nitrophenyl, 3,5-dichlorophenyl, p-cyanophenyl, m-fluorophenyl, p-tolyl, 4-propylcyclohexyl-4 ′ -Biphenyl, 4-butylcyclohexyl-4'-biphenyl, 4-pe Tilcyclohexyl-4′-biphenyl, 4-propylphenyl-2-ethynyl-4′-biphenyl), substituted or unsubstituted having 1 to 20 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 4 to 6 carbon atoms Heteroaryl groups such as pyridyl, 5-methylpyridyl, thienyl, furyl, morpholino, tetrahydrofurfuryl.

  These substituent groups V can have a structure in which a benzene ring or a naphthalene ring is condensed. Further, the substituents described in the description of V described so far may be further substituted on these substituents.

Among the substituent group V, preferred substituents for the divalent arylene group, divalent heteroarylene group, and divalent cyclic aliphatic hydrocarbon group represented by D ¹ and D ² are alkyl groups, alkoxy groups. Group, halogen atom, hydroxy group and cyano group, more preferably alkyl group, halogen atom and cyano group.

In general formula (1), L ¹ represents a divalent linking group. An alkenylene group, an alkynylene group, an ether group, an ester group, a carbonyl group, an azo group, an azoxy group, or an alkyleneoxy group is preferable, and an ester group or an alkyleneoxy group is more preferable.

In the general formula (1), the alkenylene group represented by L ¹ is preferably an alkenylene group having 2 to 20 carbon atoms, more preferably 2 to 10 carbon atoms, and examples thereof include an ethenylene group.
In the general formula (1), the alkynylene group represented by L ¹ is preferably an alkynylene group having 2 to 20 carbon atoms, more preferably 2 to 10 carbon atoms, and examples thereof include an ethynylene group.

In general formula (1), T ¹ and T ² each independently represents an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an acyl group, an acyloxy group, a halogen atom, or a cyano group.
T ¹ and T ² are preferably an alkyl group having 1 to 30 carbon atoms, more preferably 4 to 20 carbon atoms, still more preferably an alkyl group having 6 to 18 carbon atoms, and 1 to 30 carbon atoms, more preferably 4 to carbon atoms. 20, more preferably an alkoxy group having 6 to 18 carbon atoms, 2 to 30 carbon atoms, more preferably 5 to 21 carbon atoms, still more preferably an alkoxycarbonyl group having 7 to 19 carbon atoms, 2 to 30 carbon atoms, more preferably Is an acyl group having 5 to 21 carbon atoms, more preferably 7 to 19 carbon atoms, 2 to 30 carbon atoms, more preferably 5 to 21 carbon atoms, still more preferably an acyloxy group having 7 to 19 carbon atoms, a halogen atom, or It is a cyano group.

In general formula (1), the alkyl group, cycloalkyl group, alkoxy group, alkoxycarbonyl group, acyl group, and acyloxy group represented by T ¹ and T ² may or may not have a substituent. The substituent group V is exemplified as the substituent.
Examples of the substituent for the alkyl group, cycloalkyl group, alkoxy group, alkoxycarbonyl group, acyl group, and acyloxy group represented by T ¹ and T ² include halogen atoms (particularly chlorine atoms, fluorine atoms) in the substituent group V. Atom), a cyano group, a hydroxy group, an alkoxy group, and an acyl group.

Specific examples of the alkyl group represented by T ¹ and T ² in the general formula (1) include, for example, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, octadecyl group, 4-cyanobutyl group, trifluoro A methyl group and a 3-methoxypropyl group can be mentioned.
In the general formula (1), specific examples of the cycloalkyl group represented by T ¹ and T ² include a cyclopentyl group and a cyclohexyl group.
Specific examples of the alkoxy group represented by T ¹ and T ² include an octyloxy group, an undecyloxy group, a dodecyloxy group, a trifluoromethoxy group, and a 2-methoxyethoxy group.
Specific examples of the alkoxycarbonyl group represented by T ¹ and T ² include octyloxycarbonyl group and dodecyloxycarbonyl group.
Specific examples of the acyl group represented by T ¹ and T ² include octylcarbonyl group and dodecylcarbonyl group.
Specific examples of the acyloxy group represented by T ¹ and T ² include octylcarbonyloxy group and dodecylcarbonyloxy group.

T ¹ and T ² in the general formula (1) are particularly preferably an alkyl group, an alkoxy group, a halogen atom, or a cyano group.

In general formula (1), e represents an integer of 1 to 3, preferably 1 or 2. When 2 represents 2 or 3, the plurality of D ¹ may be the same or different from each other.
In general formula (1), m represents an integer of 1 to 3, and preferably 1 or 2. When m represents 2 or 3, the plurality of D ¹ may be the same or different, and the plurality of L ¹ may be the same or different.
In general formula (1), k is 1 or 2. When k is 2, the plurality of D ² may be the same or different.

In general formula (1), the total number of groups represented by D ¹ and D ² , that is, e × m + k is an integer of 3 to 5, more preferably an integer of 3 to 4. When e and k are each 2 or more, 2 or more D ¹ and D ² may be the same or different, and when m is 2 or more, 2 or more ((D ¹ ) _e −L ¹ ) is Each may be the same or different.

Particularly preferred combinations of e, m, and k are described below.
(I) e = 1, m = 2, k = 1
(Ii) e = 2, m = 1, k = 1
(Iii) e = 2, m = 1, k = 2

In the general formula (1), T ¹ and L ¹ substituted for D ¹ are preferably in the para position, and L ¹ and T ² substituted for D ² are preferably in the para position.
The smectic liquid crystal compound represented by the general formula (1) preferably has a structure represented by the following general formula (2).

In the following general formula (2), R has the same meaning as those shown in the above-mentioned substituent group V, T ¹ and T ² are each synonymous with T ¹ and T ² in the general formula (1). n represents an integer of 0 to 4.

  Specific examples of the smectic liquid crystal compound used in the present invention are shown below, but the present invention is not limited thereto.

In the present invention, the particularly preferable smectic liquid crystal compound has a refractive index of 1.5 to 2.0, particularly preferably 1.5 to 1.8. The frequency region of the electric field applied to the liquid crystal is preferably in the range of 0.1 Hz to 10 MHz, and more preferably 1 Hz to 1 MHz. Here, 0.1 Hz to 100 kHz is used as the low frequency region, preferably 1 Hz to 10 kHz, and more preferably 10 Hz to 10 kHz. 100 Hz to 10 MHz, preferably 100 Hz to 1 MHz, and more preferably 1 kHz to 1 MHz is used as the high frequency region.
The crossover frequency is preferably in the range of 1 Hz to 10 kHz.

  The combined dual-frequency driving nematic liquid crystal compound preferably has the same liquid crystal skeleton as the smectic liquid crystal compound to be applied. Particularly preferably, the smectic liquid crystal compound has a structure represented by the general formula (2), and the dual-frequency driving nematic liquid crystal compound combined therewith has a structure represented by the general formula (2). This is the case.

(4) Other liquid crystal compounds The smectic liquid crystal composition of the present invention capable of dual frequency driving does not reverse the sign of dielectric anisotropy in the low frequency region and high frequency region of the applied electric field. It may contain no nematic liquid crystal compound.

Specific examples of such nematic liquid crystal compounds include azomethine compounds, cyanobiphenyl compounds, cyanophenyl esters, fluorine substituted phenyl esters, cyclohexanecarboxylic acid phenyl esters, fluorine substituted cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexane, fluorine substituted phenylcyclohexanes. Cyano-substituted phenylpyrimidine, fluorine-substituted phenylpyrimidine, alkoxy-substituted phenylpyrimidine, fluorine-substituted alkoxy-substituted phenylpyrimidine, phenyldioxane, tolan compounds, fluorine-substituted tolan compounds, alkenylcyclohexylbenzonitrile and the like.
In addition, the liquid crystal compounds described in pages 154 to 192 and pages 715 to 722 of “Liquid Crystal Device Handbook” (Japan Society for the Promotion of Science 142nd edition, Nikkan Kogyo Shimbun, 1989) can be used.
Furthermore, a fluorine-substituted host liquid crystal suitable for TFT driving can also be used. For example, Merck's liquid crystal (ZLI-4692, MLC-6267, 6284, 6287, 6288, 6406, 6422, 6423, 6425, 6435, 6437, 7700, 7800, 9000, 9100, 9200, 9300, 10,000, etc.) Liquid crystal (LIXON 5036xx, 5037xx, 5039xx, 5040xx, 5041xx, etc.).

(5) Other additives For the purpose of changing the physical properties of the host liquid crystal (for example, temperature range of liquid crystal phase, dielectric anisotropy, refractive index anisotropy or crossover frequency), the liquid crystal of the present invention is liquid crystalline. A compound that does not show may be added. Here, the crossover frequency means a frequency at which the dielectric anisotropy changes from positive to negative in the two-frequency driving liquid crystal.
Moreover, you may add various additives, for example, a chiral agent, a ultraviolet absorber, antioxidant, etc. to the liquid-crystal composition of this invention. Examples of these additives include chiral agents for TN and STN described in pages 199 to 202 of “Liquid Crystal Device Handbook” (edited by the 142th Committee of the Japan Society for the Promotion of Science, Nikkan Kogyo Shimbun, 1989). It is done.

1-2 Polymer Material The liquid crystal composition of the present invention contains at least one polymer material.
The polymer medium layer in which the liquid crystal is dispersed and contained using a polymer material as a medium can be formed, for example, by coating a polymer solution in which a liquid crystal composition is dispersed on a substrate. As a method of dispersing the liquid crystal composition in the polymer solution, mechanical stirring, heating, ultrasonic waves, or a combination thereof can be used.

  In the polymer medium layer, the mass ratio of the smectic liquid crystal capable of being driven in two frequencies and the polymer material dispersed in the polymer medium is preferably 1:10 to 10: 1, and 1: 1 to 8: 2. Is more preferable.

In the process of forming the polymer medium layer, the liquid crystal composition is precipitated as a droplet and a method of forming a polymer medium layer containing the droplet in a dispersed manner includes, for example, the following (1) to (5): A method is mentioned.
(1) A solution (liquid crystal composition intermediate) in which a smectic liquid crystal capable of dual frequency driving according to the present invention is dissolved in a polymerizable monomer or oligomer or a mixture thereof (hereinafter collectively referred to as a prepolymer) is used as a substrate. A prepolymer layer is formed by coating on the prepolymer layer, and the prepolymer layer is cured by a polymerization reaction by irradiation with ultraviolet rays or an electron beam or by heat to form a polymer medium layer. A method of depositing liquid crystal components dissolved in a prepolymer as droplets.
(2) A method in which a smectic liquid crystal that can be driven at two frequencies is dissolved in a polymer by heating and then cooled to lower the compatibility, thereby precipitating liquid crystal components as droplets. In this method, the coating on the substrate may be performed at any timing before or after the droplets are deposited.
(3) A method in which a smectic liquid crystal that can be driven at two frequencies and a polymer are dissolved in a common solvent, and then the solvent is evaporated to deposit a liquid crystal component as droplets. In this method, the coating on the substrate may be performed before or after deposition of the droplets.
(4) A method in which a smectic liquid crystal material and a polymer capable of dual frequency driving are mixed in a general-purpose solvent to form an emulsified state, the solvent is evaporated, and a liquid crystal component is deposited as droplets.
(5) A method of crystallizing a smectic liquid crystal that can be driven at two frequencies at a low temperature, pulverizing and dispersing the smectic liquid crystal in a polymer medium, and then coating on a substrate.

  As the light control material and the liquid crystal display element of the present invention, the method (1) is preferable from the viewpoint that a strong scattering state can be formed. In the method (1), it is preferable to use a polymerization initiator for the liquid crystal composition intermediate because a uniform scattering state can be formed. As this polymerization initiator, known ones can be appropriately applied.

  The average particle diameter of the liquid crystal droplets in the polymer material is preferably 0.1 to 20 μm, more preferably 0.5 to 10 μm, and still more preferably 1 to 5 μm. When the average particle size of the liquid crystal droplets is less than 0.1 μm, the light wavelength and the average particle size of the liquid crystal droplets may be the same size order, so that light scattering may be weakened. Since the ratio of the interface between the polymer and the liquid crystal is small, light scattering may be weak.

  The polymer material used for the polymer medium layer is not particularly limited. Water-soluble polymers such as methylcellulose, polyvinyl alcohol, polyoxyethylene, polyvinyl butyral, gelatin, polyacrylates, polymethacrylates, polyamides, polyesters, polycarbonates, polyvinyl alcohol derivatives represented by vinyl acetate and polyvinyl butyral Water-insoluble polymers such as cellulose derivatives such as triacetyl cellulose, polyurethanes, and styrenes are used. Examples of the polymer used in the light control material of the present invention include polyacrylates and polymethacrylates from the viewpoint of a combination that easily forms a state in which the liquid crystal is dispersed in a uniform polymer by polymer phase separation of the liquid crystal and the polymer. preferable.

As described above, it is preferable to use a polymer material having a refractive index close to the refractive index (n‖) in the major axis direction of the liquid crystal as described above. Since the refractive index (n‖) in the major axis direction of the liquid crystal suitably used in the present invention is about 1.5 to 1.8, the refractive index (n _p ) of the polymer material is also 1.5 to 1.8. It is preferable that it is a grade. Polymer materials having such a refractive index (n _p ) are generally polyacrylates and polymethacrylates. Further, when the polymer material is adjusted in the direction of a low refractive index, a part having a low refractive index (for example, a fluorine atom) is introduced as a functional group at the ester site of polyacrylates or polymethacrylates. In addition, when adjusting the polymer material in the direction of a high refractive index, the refractive index is adjusted by introducing a part having a high refractive index (for example, a cyano group) as a functional group of the ester portion of polyacrylates or polymethacrylates. Can be adjusted.

1-3. Other Additives Furthermore, a surfactant can be used in the liquid crystal composition for the purpose of stabilizing the dispersion state of the liquid crystal. There is no particular limitation on the surfactant applicable to the present invention, but nonionic surfactants are preferable, and sorbitan fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkyl ethers, fluoroalkylethylene oxides, etc. are used. It is done.

  Further, a coloring material may be added for the purpose of coloring the liquid crystal composition. As the color material, a dye or a pigment is preferably used, but a dye is more preferable. As the dye, a so-called dichroic dye exhibiting dichroism is particularly preferable. The chromophore of the dichroic dye may be any, for example, azo dye, anthraquinone dye, perylene dye, merocyanine dye, azomethine dye, phthaloperylene dye, indigo dye, azulene dye, dioxazine dye, polythiophene dye, phenoxy Examples include sagin dyes. Preferred are azo dyes, anthraquinone dyes, and phenoxazine dyes, and particularly preferred are anthraquinone dyes and phenoxazone dyes (phenoxazin-3-one).

The azo dye may be any one such as a monoazo dye, a bisazo dye, a trisazo dye, a tetrakisazo dye, and a pentakisazo dye, but is preferably a monoazo dye, a bisazo dye, or a trisazo dye.
The ring structure contained in the azo dye includes aromatic groups (benzene ring, naphthalene ring, etc.) as well as heterocyclic rings (quinoline ring, pyridine ring, thiazole ring, benzothiazole ring, oxazole ring, benzoxazole ring, imidazole ring, Benzimidazole ring, pyrimidine ring, etc.).

  As the substituent of the anthraquinone dye, those containing an oxygen atom, a sulfur atom or a nitrogen atom are preferable, and examples thereof include an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylamino group and an arylamino group. The substitution number of the substituent may be any number, but di-substitution, tri-substitution, and tetrakis substitution are preferred, and di-substitution and tri-substitution are particularly preferred. The substitution position of the substituent may be any place, but preferably 1,4-position disubstitution, 1,5-position disubstitution, 1,4,5-position trisubstitution, 1,2,4-position trisubstitution, They are 1,2,5-trisubstituted, 1,2,4,5-tetrasubstituted, 1,2,5,6-tetrasubstituted structures.

  The substituent of the phenoxazone dye (phenoxazin-3-one) preferably includes an oxygen atom, a sulfur atom or a nitrogen atom, and examples thereof include an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylamino group and an arylamino group.

2. Liquid Crystal Element The liquid crystal element of the present invention is a laminate having an electrode and a liquid crystal layer containing the liquid crystal composition described above, and changes the amount of incident light reflected.

2-1. Electrode In this invention, the well-known thing used for a liquid crystal element can be applied suitably for an electrode. When the liquid crystal element is used as a liquid crystal display element, at least the electrode on the observation surface side is preferably a transparent electrode, and in the case of a light control material, the electrodes on both surfaces are preferably transparent electrodes.
The transparent electrode can be formed from, for example, indium oxide, indium tin oxide (ITO), tin oxide, or the like. Among these, indium tin oxide (ITO) is preferably used from the viewpoint of low resistance and high transparency.
As for the transparent electrode, for example, those described in pages 232 to 239 of “Liquid Crystal Device Handbook” (edited by the Japan Society for the Promotion of Science 142nd Committee, Nikkan Kogyo Shimbun, 1989) are used.

2-2. Liquid crystal layer (polymer medium layer)
The liquid crystal layer in the liquid crystal element is sandwiched between the electrodes. Specifically, it can be produced by arranging a liquid crystal composition in a space formed between the substrates, facing each other at intervals of 1 to 50 μm via a spacer or the like between the electrodes.
As the spacer, for example, those described in pages 257 to 262 of “Liquid Crystal Device Handbook” (edited by Japan Society for the Promotion of Science 142nd Committee, Nikkan Kogyo Shimbun, 1989) can be used. In addition, the light control material of this invention can be arrange | positioned in the space between board | substrates by apply | coating or printing on a board | substrate.
In addition, as demonstrated with the said liquid-crystal composition, the liquid-crystal layer in this invention is a polymer medium layer which contains a polymer material as a medium and disperse | distributes a liquid crystal. In the light modulating material and the liquid crystal display element of the present invention, the thickness of the polymer medium layer is preferably 1 to 50 μm from the viewpoint of being able to be driven at a low voltage while maintaining a high scattering state.

2-3. Display Method Since the liquid crystal element of the present invention includes a smectic liquid crystal that can be driven at two frequencies, the display method of the liquid crystal element of the present invention is driven by high-frequency and low-frequency AC voltages to switch the display.

The driving of the polymer medium layer in the present invention will be described with reference to FIG.
FIG. 1A is a diagram illustrating a state when a low-frequency voltage is applied, and FIG. 1B is a diagram illustrating a state when a high-frequency voltage is applied. The dual frequency driving liquid crystal has a positive dielectric anisotropy with respect to a low frequency voltage and a negative dielectric anisotropy with respect to a high frequency voltage.

In the polymer medium layer 10, a smectic liquid crystal 14 that can be driven at two frequencies is dispersed in a polymer material 12.
First, when a low-frequency voltage is applied to the polymer medium layer 10, the liquid crystal molecules in the polymer medium layer 10 are aligned parallel to the direction of the electric field because the dielectric anisotropy of the liquid crystal 14 is positive. (FIG. 1A). That is, the liquid crystal molecules are aligned perpendicular to the electrode 16. Therefore, the refractive index of the liquid crystal 14 in this state is the refractive index (n‖) in the major axis direction. On the other hand, since the polymer material 12 in the polymer medium layer 10 is not oriented, the refractive index becomes its own refractive index (n _p ). Here, when the refractive index (n‖) in the major axis direction of the liquid crystal 14 and the refractive index (n _p ) of the polymer material 12 are close to each other, light is emitted at the boundary between the liquid crystal 14 and the polymer material 12. Therefore, the light is transmitted without being scattered and becomes transparent.
Even if the application of voltage is stopped in this state, the smectic liquid crystal is used, so that there is a memory property and a transparent state can be maintained. Therefore, the amount of power used can be saved.

  Next, when a high frequency voltage is applied to the polymer medium layer 12, since the dielectric anisotropy of the liquid crystal 14 is negative, the liquid crystal molecules are aligned perpendicular to the direction of the electric field (FIG. 1B )). That is, the liquid crystal molecules are aligned horizontally with respect to the electrode 16. Therefore, it is possible to switch the alignment state of the liquid crystal molecules by switching between a low frequency voltage and a high frequency voltage.

Here, when the liquid crystal 14 having a large refractive index anisotropy (Δn) is used, the difference between the refractive index (n‖) in the major axis direction of the liquid crystal molecule and the refractive index (n⊥) in the minor axis direction of the liquid crystal molecule is growing. As described above, since the refractive index (n _p ) of the polymer material 12 is set to be close to the refractive index (n‖) in the major axis direction of the liquid crystal 14, the refractive index anisotropy (Δn) In a liquid crystal having a large thickness, the difference between the refractive index (n _p ) of the polymer material 12 and the refractive index (n⊥) in the minor axis direction of the liquid crystal 14 also increases. Since light is scattered at the boundary between different substances having different refractive indexes, the entire polymer medium layer 10 becomes cloudy.
Even if the application of voltage is stopped in this state, the smectic liquid crystal is used, so that it has a memory property and can maintain a transparent state. Therefore, the amount of power used can be saved.

Thus, by using a liquid crystal that can be driven at two frequencies, the orientation of the liquid crystal dispersed in the polymer material can be controlled. Further, by using a smectic liquid crystal, a memory property can be exhibited, and the display state can be maintained even when voltage application is stopped.
As a result, the light control material and the liquid crystal display device to which the liquid crystal element is applied can exhibit high light control performance or display performance and can reduce power consumption.

  In addition, when a general color material is included in the liquid crystal, the colored transparent state and the colored scattering state can be switched. When the color material is a dichroic dye, the colorless transparent state and the colored scattering state are switched. Can be switched.

3. Light Control Material and Liquid Crystal Display Element The liquid crystal display element of the present invention includes a pair of bases, the liquid crystal element is provided between the bases, and changes the amount of reflected light of incident light. The light control material of the present invention includes a pair of bases, the liquid crystal element is provided between the bases, and changes the transmittance of incident light. The light control material is applied to, for example, a light control glass that arbitrarily adjusts the transmittance of light from a window. Therefore, in the case of the light control material, the observer observes the state in which the light passes through the light control material only once, whereas in the case of the liquid crystal display element, after the external light passes through the liquid crystal display element, a reflector or the like The observer observes the state of being reflected by the light and again passing through the liquid crystal display element.

3-1. Substrate The substrate is usually provided as a support, on which the electrode is provided. Usually, a substrate made of glass or plastic is used, but a plastic substrate is preferable from the viewpoint that it can be bent, is light, and can be manufactured into a roll.
Examples of the plastic substrate include acrylic resin, polycarbonate resin, epoxy resin, PES, and PEN. As the substrate, for example, those described in pages 218 to 231 of “Liquid Crystal Device Handbook” (edited by the Japan Society for the Promotion of Science 142nd Committee, Nikkan Kogyo Shimbun, 1989) can be used.
In the case of a light control material, as described above, the substrate is preferably transparent in order to observe transmitted light. In the case of a liquid crystal display element, in order to observe reflected light, at least the substrate on the observation surface side. Is preferably transparent.

3-2. Other members Examples of other members include a barrier film, an ultraviolet absorbing layer, an antireflection layer, a hard coat layer, a stain prevention layer, an organic interlayer insulating film, a metal reflector, a retardation plate, and an alignment film. These may be used alone or in combination of two or more.

(1) Barrier layer In the light control material and the liquid crystal display element of the present invention, the barrier layer is preferably provided in order to suppress deterioration of the member due to intrusion of water or oxygen.
The barrier layer may be formed of any one of an organic polymer system, an inorganic system, and a composite system thereof. Examples of the organic polymer system include ethylene-vinyl alcohol (EVOH), polyvinyl alcohol (PVA / PVOH), nylon MXD6 (N-MXD), and nanocomposite nylon. Examples of the inorganic system include silica, alumina, and binary system. Details thereof are described, for example, in “Development of High Barrier Materials, Film Formation Technology and Barrier Properties Measurement / Evaluation Method” (Technical Information Association, 2004).
The barrier layer is provided on the surface of the substrate on the side where the liquid crystal layer is not provided. Both substrates may be provided with a barrier layer or may be provided only on one substrate. Preferably, both substrates are provided with a barrier layer.

(2) Ultraviolet absorbing layer In the light modulating material and the liquid crystal display element of the present invention, the ultraviolet absorbing layer is preferably provided in order to prevent deterioration of the element due to ultraviolet rays.
As the ultraviolet absorbing layer, an antioxidant such as 2,2-thiobis (4-methyl-6-tert-butylphenol), 2,6-di-tert-butylphenol: 2- (3-tert-butyl-5-methyl) It is preferable to contain ultraviolet absorbers such as 2-hydroxyphenyl) -5-chlorobenzotriazole and alkoxybenzophenone.

(3) Antireflection film In the light modulating material and the liquid crystal display element of the present invention, the antireflection film is preferably provided so that incident light is prevented from being reflected from the surface of the element and light is sufficiently incident on the element.
The antireflection film is formed using an inorganic material or an organic material, and the film configuration may be a single layer or a multilayer. Furthermore, it may be a multilayer structure (inorganic-organic composite film) of an inorganic material film and an organic material film. The antireflection film can be provided on one side or both sides of the light control material and the substrate of the liquid crystal display element. When provided on both sides, the antireflection films on both sides may have the same configuration or different configurations. For example, the antireflection film on one surface may have a multilayer structure, and the antireflection film on the other surface side may be simplified to have a single layer structure. Moreover, an antireflection film can be provided directly on the transparent electrode.

The inorganic material used for the antireflection _{film, SiO 2, SiO, ZrO 2} , TiO 2, TiO, Ti 2 O 3, Ti 2 O 5, Al 2 O 3, Ta 2 O 5, CeO 2, MgO, Y 2 O ₃ , SnO ₂ , MgF ₂ , WO _{3 and the} like can be mentioned, and these can be used alone or in combination of two or more. Among these, since the lens is a plastic lens, SiO ₂ , ZrO ₂ , TiO ₂ , and Ta ₂ O ₅ that can be vacuum-deposited at a low temperature are preferable.
As a multilayer film formed of an inorganic material, the total optical film thickness of the ZrO ₂ layer and the SiO ₂ layer from the lens side is λ / 4, the optical film thickness of the ZrO ₂ layer is λ / 4, and the outermost SiO ₂ layer is SiO _2. A laminated structure in which a high refractive index material layer and a low refractive index material layer having an optical film thickness of λ / 4 are alternately formed is exemplified. Here, λ is a design wavelength, and usually 520 nm is used. The outermost layer is preferably made of SiO ₂ because it has a low refractive index and can impart mechanical strength to the antireflection film.
In the case of forming an antireflection film with an inorganic material, for example, a vacuum deposition method, an ion plating method, a sputtering method, a CVD method, a method of depositing by a chemical reaction in a saturated solution, or the like can be employed.

  Examples of the organic material used for the antireflection film include FFP (tetrafluoroethylene-hexafluoropropylene copolymer), PTFE (polytetrafluoroethylene), ETFE (ethylene-tetrafluoroethylene copolymer), and the like. The refractive index of the lens material and the hard coat film (if any) is selected. As a film forming method, a film can be formed by a coating method having excellent mass productivity such as a spin coating method and a dip coating method in addition to a vacuum deposition method.

(4) Colored layer In the case of the liquid crystal display element and the light control material of the present invention, it is preferable to provide a colored layer on the back surface. That is, when light is scattered or transmitted by the polymer medium layer (liquid crystal layer), in the case of a liquid crystal display element, the white state and the colored transparent state are switched by the colored layer provided on the back surface. In the case of a light-modulating material, the observer observes the state of light transmitted through the colored layer on the back surface, so that the colored scattering state and the colored transparent state can be switched by the colored layer provided on the back surface.
The colored layer may be black or may absorb only a specific wavelength. In the case of black, a structure in which a binder in which carbon black is dispersed is provided on a support is preferably used. In the case of absorbing a specific wavelength, ordinary pigments and dyes are preferably used. A pigment is preferable.
The pigment may be either an inorganic pigment or an organic pigment. Examples of pigments include titanium oxide pigments, iron oxide pigments, bronze powder pigments, alumina pigments, precipitated barium sulfate pigments, zinc white pigments, titanium black pigments, azo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, and selenium. Examples thereof include pigments, perylene pigments, perinone pigments, dioxazine pigments, quinophthalone pigments, diketopyrrolopyrrole pigments, thioindigo pigments, indigo pigments, fluorescent pigments, aniline black pigments, and carbon black pigments.

  The colored layer preferably contains a binder so as to be uniformly layered. Examples of such a binder include water-soluble polymers such as methyl cellulose, polyvinyl alcohol, polyoxyethylene, polyvinyl butyral, and gelatin, polyacrylates, polymethacrylates, polyamides, polyesters, polycarbonates, vinyl acetate, and polyvinyl. Examples thereof include polyvinyl alcohol derivatives typified by butyral, cellulose derivatives such as triacetylcellulose, water-insoluble polymers such as polyurethanes and styrenes.

(5) Reflector In the case of a liquid crystal display element, it is preferable to provide a reflector in order to observe reflected light. An example of such a reflector is a white scattering layer containing titanium oxide or the like. It is preferable that the reflection plate is installed on the back side of the colored layer.

(6) Alignment film In the liquid crystal display element and the light control material of the present invention, an alignment film may be provided from the viewpoint of controlling the alignment of the polymer liquid crystal when the polymer material in the polymer medium layer has liquid crystallinity. Good.
As the alignment film, it is preferable to use polyimide, a silane coupling agent, polyvinyl alcohol, gelatin, or the like, and it is preferable to use a polyimide or a silane coupling agent from the viewpoints of alignment ability, durability, insulation, and cost.
The orientation method may or may not be rubbed. Regarding the alignment state, either the horizontal state or the vertical state may be used.

  In addition, since the liquid crystal display element and the light control material of the present invention use smectic liquid crystal that can be driven at two frequencies as the liquid crystal as described above, the alignment state can be stably maintained without an alignment film.

(7) Other layers As the hard coat layer, a known ultraviolet curing or electron beam curing acrylic or epoxy resin can be used. As the antifouling film, a water / oil repellent material such as a fluorine-containing organic polymer can be used.
In the case of a liquid crystal display element, it is preferable to provide a white scattering layer on the non-display surface side in order to observe reflected light.

3-3. Method for Driving Light Control Material The substrate having electrodes provided on the entire surface is opposed to the liquid crystal composition. When a color material is not contained in the liquid crystal composition, it becomes colorless and transparent when a voltage is applied at a low frequency, and becomes white when a voltage is applied at a high frequency. When a normal color material is contained, coloring becomes transparent when a voltage is applied at a low frequency, and coloring scattering occurs when a voltage is applied at a high frequency. When the coloring material is a dichroic dye, it is colorless and transparent when a voltage is applied at a low frequency, and is colored and scattered when a voltage is applied at a high frequency. On the other hand, when a colored layer is provided, it is colored and transparent when a voltage is applied at a low frequency, and is colored and scattered when a voltage is applied at a high frequency.

3-4. Display Method of Liquid Crystal Display Element The liquid crystal display element of the present invention can be driven and displayed using a simple matrix driving system or an active matrix driving system using a thin film transistor (TFT). The driving method is described in detail, for example, on pages 387 to 460 of “Liquid Crystal Device Handbook” (edited by the 142th Committee of the Japan Society for the Promotion of Science, Nikkan Kogyo Shimbun, 1989). Available as a method.
A liquid crystal element is sandwiched between the two substrates. One liquid crystal element may be sandwiched or a plurality of layers may be stacked as shown in FIG. Further, they may be juxtaposed as shown in FIG. When layers exhibiting different colors are stacked or juxtaposed, color display can be performed.
The coloring is the same as that shown in the driving method of the light modulating material. However, when a colored layer is provided, in order to observe reflected light, it is colored and transparent when a voltage is applied at a low frequency, but becomes white when a voltage is applied at a high frequency.

3-5. Applications The light control material and liquid crystal display element of the present invention exhibit high light control performance or display performance and can reduce power consumption, and are suitable as light control, security, in-vehicle use, interior, advertisement, and information display board. Can be used.

  The present invention will be described more specifically with reference to the following examples. The materials, reagents, amounts and ratios, operations, etc. shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples. .

[Example 1]
<Production of light control material>
1. Adjustment of liquid crystal The following smectic liquid crystal (1) was synthesized according to the following scheme.

Smectic liquid crystal (1) 40 mg of the above specific example compound, 200 mg of the following dual frequency driving nematic liquid crystal (H-1) described in Applied Physics Letters, Vol. 25, 186-188 (1974) and the following nematic liquid crystal compound (Δε negative) H-2) 30 mg of the mixture was heated on a hot plate at 180 ° C. for 1 hour, and then cooled to room temperature to obtain liquid crystal composition-1.
The threshold voltage of the liquid crystal composition-1 was 6 V / μm, and the crossover frequency was 700 Hz. The smectic liquid crystal (1) was confirmed to be a compound exhibiting a smectic A phase from observation with a polarizing microscope.

2. Adjustment of Light Control Element A polyimide horizontal alignment film (manufactured by Nissan Chemical Industries) was attached by spin coating and baking on a glass substrate with ITO (manufactured by EHC) as a transparent electrode. Next, the obtained glass substrate with a horizontal alignment film was rubbed.
A liquid crystal composition was obtained by mixing and dissolving 0.10 g of the above liquid crystal composition, 20 mg of hydroxybutyl acrylate, 20 mg of 2-ethylhexyl acrylate, and a very small amount of a photopolymerization initiator IRG-816 (manufactured by Ciba Geigy). A small amount of 8 μm spherical spacer (manufactured by Sekisui Chemical Co., Ltd.) is mixed into the obtained liquid crystal composition, and the glass substrate with ITO is sandwiched so that the alignment film side is in contact with the liquid crystal layer. Sealed with a sealant (manufactured by Sekisui Chemical). Next, UV irradiation (20 mW / m ² ) was performed, photopolymerization was performed to make the monomer a polymer, phase separation between the polymer material and the liquid crystal was performed, and a polymer medium layer was formed.
The liquid crystal droplets in the obtained polymer medium layer had an average particle diameter of 4 μm, and the refractive index of the polymer material was 1.5.

3. Evaluation The obtained light control material of the present invention was in a scattered white state when no voltage was applied, and the transmittance at 550 nm was measured with a UV / vis spectrum (manufactured by Shimadzu Corporation) and found to be 10.0%.
Next, when a voltage (200 V, 60 Hz) was applied using a signal generator (manufactured by Tektronix Co., Ltd.), the liquid crystal layer became transparent. In that case, the transmittance at 550 nm was 84%.
Furthermore, when a voltage (200 V, 10 kHz) was applied, the liquid crystal layer again became a scattering white state, and the transmittance at 550 nm was 9.0%.

  Moreover, each scattering white state and transparent state were maintained for 1 hour or more after the voltage application was stopped. That is, it was confirmed that the memory property was given. Therefore, it was confirmed that the light control material of this invention has a light control function which can control the transmittance | permeability of light electrically. At the same time, when the voltage was applied, the amount of current flowing through the light control material was evaluated, but almost no current flowed. That is, it was confirmed that the light control material of the present invention did not form a scattering state based on dynamic scattering by current drive.

[Comparative Example 1]
A dimming material was prepared in the same manner as in Example 1 except that 20 mg of the monomer hydroxybutyl acrylate, 20 mg of 2-ethylhexyl acrylate, and photopolymerization initiator IRG-816 (manufactured by Ciba Geigy) were not mixed. When applied, the scattered white state did not form and remained transparent. That is, it was confirmed that it does not function as a light control material.

[Example 2]
<Adjustment of light control material>
1. Production of Plastic Substrate An undercoat layer and a back layer were produced for PEN (Dupont-Teijin Q65A) in the same manner as in the production of Sample 110 of Example 1 of JP-A-2000-105445. That is, 100 parts by weight of polyethylene-2,6-naphthalate polymer and Tinuvin P.I. 326 (manufactured by Ciba-Geigy Ciba-Geigy) was dried, melted at 300 ° C, extruded from a T-die, and stretched 3.3 times at 140 ° C, followed by 130 ° C. The plastic substrate (PEN) of the present invention having a thickness of 90 μm was obtained by performing transverse stretching of 3.3 times and further heat-fixing at 250 ° C. for 6 seconds.

2. Production of Transparent Electrode Layer Conductive indium tin oxide (ITO) was coated on one side of the plastic substrate obtained above, and a transparent thin film electrode having a thickness of 200 nm was laminated. The surface resistance was about 20 Ω / cm ² and the light transmittance (500 nm) was 85%.
Next, a SiO ₂ thin film (100 nm) was provided as an antireflection film on the ITO surface by sputtering. The light transmittance (500 nm) was 90%.

2. Production of Liquid Crystal Layer A liquid crystal layer was produced in the same manner as in Example 1 except that the plastic substrate was used.

3. Attaching a barrier layer (production of an organic-inorganic hybrid layer)
8 g of Soarnol D2908 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., ethylene-vinyl alcohol copolymer) was dissolved in a mixed solvent of 118.8 g of 1-propanol and 73.2 g of water at 80 ° C. 2.4 ml of 2N hydrochloric acid was added to 10.72 g of this solution and mixed. While stirring this solution, 1 g of tetraethoxysilane was added dropwise and stirring was continued for 30 minutes.
Next, the obtained coating solution was applied onto the plastic substrate with a wire bar. Thereafter, an organic-inorganic hybrid layer having a film thickness of about 1 μm was formed on the light control material by drying at 120 ° C. for 5 minutes.

4). Attaching the UV absorbing layer 42 g of water, 40 g of silanol-modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd .: trade name R2105) and 13.5 g of the capsule solution for UV filter were mixed, and then 50 mass% of 2- (3-t-butyl-5 -Methyl-2-hydroxyphenyl) -5-chlorobenzotriazole aqueous solution 17 g, 20% by mass colloidal silica dispersion (Nissan Chemical Co., Ltd .: trade name Snowtex 0) 65 g, polyoxyethylene alkyl ether phosphate (Toho Chemical) 2.5 g of Neoscore CM57 (manufactured by Koyo Co., Ltd.) and 2.5 g of polyethylene glycol dodecyl ether (Emulgen 109P, manufactured by Kao Corporation) were mixed to obtain a coating solution for an ultraviolet filter layer.
Next, the obtained coating solution was coated on the barrier layer with a wire bar. Thereafter, an ultraviolet absorbing layer having a film thickness of about 1 μm was formed on the light-modulating material by drying at 120 ° C. for 5 minutes.

<Evaluation of display performance>
When the obtained display element of the present invention was evaluated in the same manner as in Example 1, it was confirmed that dimming with a high contrast ratio was possible.
In addition, when repeated evaluation of switching between the scattered white state and the transparent state was performed 1000 times, deterioration of the light control performance was not visually observed. Furthermore, even when Xe lamp irradiation (100,000 lux, 100 hours) was performed, no deterioration in light control performance was observed visually. That is, it was confirmed that the light control material of the present invention is excellent in both repeated durability and light durability.

[Example 3]
In Example 1, instead of the liquid crystal compound used in the liquid crystal composition-1, the following liquid crystal compound was changed to prepare the liquid crystal composition-2, and the horizontal alignment film was changed to a polyimide vertical alignment film (manufactured by Nissan Chemical Industries). Except for this point, the light control material of the present invention was prepared in the same manner as in Example 1.
The obtained liquid crystal composition-2 had a threshold voltage of 18 V / μm and a crossover frequency of 1 kHz. It was also confirmed that the liquid crystal composition-2 exhibited a smectic A phase at room temperature.
When a 225 V AC voltage (60 Hz and 100 kHz) was applied as the drive voltage and the same evaluation as in Example 1 was performed, it was confirmed that the light control material of the present invention has a high light control function.

[Example 4]
<Preparation of liquid crystal display element>
Liquid crystal composition-1 was dispersed in a 5% by weight aqueous solution of polyvinyl alcohol (trade name: Kuraray Poval, Kuraray, refractive index n _p : 1.60) by stirring with a homogenizer. The average particle diameter of the liquid crystal droplets in the obtained liquid crystal dispersion aqueous solution was 3 μm.
A small amount of a 10 μm spherical spacer (manufactured by Sekisui Chemical Co., Ltd.) was mixed, and the obtained liquid crystal dispersion aqueous solution was applied on a glass substrate with ITO with a wire bar and dried at 80 ° C. for 2 hours. Next, after bonding two glass substrates with ITO, it sealed by the method similar to Example 1, and the liquid crystal display element of this invention was produced.
The obtained liquid crystal display element was provided with a black absorption layer. The black absorption layer is a coating solution prepared by dispersing carbon black whose surface activity has been deactivated by surface treatment together with 5% by mass of carboxycellulose on a non-display surface side glass substrate that is not on the liquid crystal layer side. And produced.

<Evaluation of display performance>
The obtained liquid crystal display element of the present invention turned black when a low-frequency voltage (125 V, 60 Hz) was applied using a signal generator (manufactured by Tektronix). Moreover, when a high frequency voltage (125V, 100kHz) was applied, it became scattering white. It was confirmed that it functions as a reflective liquid crystal display element that can electrically control the black state and the white scattering state.

[Example 5]
In Example 1, the light control material of this invention was prepared like Example 1 except having further added 1.0 mass% of the following dichroic dye 1 to the liquid-crystal composition.
When the same evaluation as in Example 1 was performed, the obtained light control material of the present invention was in a scattered red state when no voltage was applied, and the transmittance at 550 nm was measured by a UV / vis spectrum (manufactured by Shimadzu). However, it was 5.0%. Next, when a voltage (200 V, 60 Hz) was applied using a signal generator (manufactured by Tektronix Co., Ltd.), the liquid crystal layer became colorless and transparent. In that case, the transmittance at 550 nm was 74%. Furthermore, when a voltage (200 V, 10 kHz) was applied, the liquid crystal layer was again in a scattered red state, and the transmittance at 550 nm was 4.0%.
Further, each of the scattered red state and the transparent state was maintained for 1 hour or more after the voltage application was stopped. That is, it was confirmed that the memory property was given.

It is a figure explaining the drive of a polymer medium layer. FIG. 1A is a diagram illustrating a state when a low-frequency voltage is applied, and FIG. 1B is a diagram illustrating a state when a high-frequency voltage is applied. It is a figure which shows the structure of a liquid crystal display element. FIG. 2A shows a case of stacking, and FIG. 2B shows a case of juxtaposition.

Explanation of symbols

10 Polymer Media Layer 12 Polymer Material 14 Liquid Crystal 16 Electrode

Claims (22)

  A liquid crystal composition comprising at least one kind of smectic liquid crystal capable of being driven at two frequencies and at least one polymer material.   The liquid crystal composition according to claim 1, wherein the smectic liquid crystal exhibits a smectic A phase.   The liquid crystal composition according to claim 1, wherein the smectic liquid crystal contains at least one nematic liquid crystal compound.   4. A liquid crystal composition intermediate comprising at least one monomer and at least one smectic liquid crystal capable of being driven at two frequencies is polymerized. The liquid crystal composition described in 1.   The liquid crystal composition according to claim 4, wherein the liquid crystal composition intermediate further contains a polymerization initiator.   The liquid crystal composition according to claim 4 or 5, wherein the liquid crystal composition intermediate further contains a nematic liquid crystal compound.   The liquid crystal composition according to claim 1, further comprising a color material.   The liquid crystal composition according to claim 7, wherein the coloring material is a dichroic dye. The liquid crystal composition according to any one of claims 1 to 8, wherein the smectic liquid crystal contains a smectic liquid crystal compound represented by the following general formula (1).
Formula ^{(1): T 1 - {} (D 1) e -L 1} m - (D 2) k -T 2
[Wherein, D ¹ and D ² each independently represent an arylene group, a heteroarylene group or a divalent cyclic aliphatic hydrocarbon group, L ¹ represents a divalent linking group, and T ¹ and T ² each represent Independently, it represents an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an acyl group, an acyloxy group, a halogen atom or a cyano group, e represents a number of 0 to 5, and m represents a number of 1 to 3, respectively. K represents a number of ¹ to ² , the total number of groups represented by D ¹ and D ² is a number of 3 to 5, and when e and k are each 2 or more, 2 or more of D ¹ and D ² may be the same or different, and when m is 2 or more, two or more {(D ¹ ) _e -L ¹ } may be the same or different. ]   A liquid crystal element comprising a laminate having an electrode and a liquid crystal layer including the liquid crystal composition according to any one of claims 1 to 9 provided between the electrodes.   The liquid crystal element according to claim 10, wherein the electrode is a transparent electrode made of ITO (indium tin oxide).   12. A display method, wherein the display is switched by driving the liquid crystal element according to claim 10 with a high frequency and a low frequency alternating voltage.   A liquid crystal display element comprising a pair of bases, wherein the liquid crystal element according to claim 10 or 11 is provided between the bases, and the amount of reflected light of incident light is changed.   The liquid crystal display element according to claim 13, wherein a colored layer is provided on a surface side of the substrate on which the liquid crystal element is not provided.   The liquid crystal display element according to claim 13 or 14, wherein the substrate is made of a polymer.   The liquid crystal display element according to claim 13, further comprising an antireflection film.   The liquid crystal display element according to claim 16, wherein the antireflection film is an inorganic thin film, an organic thin film, or an inorganic-organic composite film.   A light-modulating material comprising a pair of substrates and having the liquid crystal element according to claim 10 or 11 between the substrates to change the transmittance of incident light.   The light control material according to claim 18, wherein a colored layer is provided on a surface side of the substrate on which the liquid crystal element is not provided.   The light control material according to claim 18, wherein the substrate is a polymer support.   The light control material according to any one of claims 18 to 20, further comprising an antireflection film.   The light control material according to claim 21, wherein the antireflection film is an inorganic thin film, an organic thin film, or an inorganic-organic composite film.

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