JP2006169429A - Liquid crystal composition and liquid crystal element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal composition useful for producing a liquid crystal element having high color displaying performance and provide a liquid crystal element having high visibility and color displaying performance. <P>SOLUTION: The liquid crystal composition contains at least one kind of charged particle and at least one kind of dichroic dye. The dichroic dye is a dye having a substituent expressed by general formula (1): -(Het)<SB>j</SB>-[(B<SP>1</SP>)<SB>p</SB>-(Q<SP>1</SP>)<SB>q</SB>-(B<SP>2</SP>)<SB>r</SB>]<SB>n</SB>-C<SP>1</SP>(Het is oxygen atom or sulfur atom; B<SP>1</SP>and B<SP>2</SP>are each a bivalent arylene group, heteroarylene group or a bivalent cycloaliphatic hydrocarbon group; Q<SP>1</SP>is a bivalent linking group; C<SP>1</SP>is an alkyl, a cycloalkyl, an alkoxy, an alkoxycarbonyl, an acyl or an acyloxy; j is 0 or 1; p, q and r are each 0-5; n is 1-3; and the total number of the B<SP>1</SP>and B<SP>2</SP>groups is 3-10). The invention further provides a liquid crystal element having a liquid crystal layer containing the liquid crystal composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal composition and a liquid crystal element having a liquid crystal layer containing the liquid crystal composition, and more particularly to a liquid crystal element combining a guest-host method and an electrophoresis method.

  With the spread of digital information, the importance of displays (hereinafter referred to as electronic paper) for displaying digital information is increasing. The performance required for electronic paper includes high visibility and low power consumption. High visibility means a white background close to paper. For this purpose, a display method based on a scattered white background similar to paper is suitable. Regarding the low power consumption, the reflective display method has lower power consumption than the self-luminous display method. Until now, many methods have been proposed as electronic paper. For example, a reflective liquid crystal display method, an electrophoretic display method, a magnetophoretic display method, a dichroic rotation method, an electrochromic display method, a leucothermal display method, and the like. Both methods are not satisfactory from the viewpoint of high visibility, and their improvement has been demanded.

  Many liquid crystal elements (liquid crystal display elements) have already been proposed. Among them, the guest-host liquid crystal element is capable of bright display and is expected as a liquid crystal element suitable for a reflection type. In a guest-host type liquid crystal device, a liquid crystal composition in which a dichroic dye is dissolved in a nematic liquid crystal is enclosed in a cell, and an electric field is applied to the liquid crystal composition. In this method, the orientation is changed and the light absorption state of the cell is changed. This guest-host type liquid crystal element is expected to be brighter than a conventional liquid crystal display method because it can be driven without using a polarizing plate. As a guest-host method that does not use a polarizing plate, that is, a method that realizes a light absorption state that does not depend on polarization, for example, a method that uses a chiral nematic phase in combination with a chiral agent, or a composite with a polymer matrix is used. Although a polymer dispersion type (PDLC) has been proposed, the display performance is still not at a satisfactory level, and its improvement has been demanded.

  The electrophoresis method is a method in which display is performed by electrically moving charged particles by applying a DC voltage to a state where colored charged particles are dispersed in a dispersion medium. Titanium oxide fine particles are used as white charged particles, and carbon black fine particles are used as black charged particles. This method is a method that does not use a polarizing plate and is a method that does not depend on the viewing angle and is expected to provide a bright display. However, the display performance is still not at a satisfactory level. In addition, although the electrophoretic method is widely studied for black and white display, the colorization method is still not at a satisfactory level, and an improvement has been demanded.

  As a colorization method for the guest-host type liquid crystal element, as shown in FIG. 3, three liquid crystal layers 52, 54 and 56 each containing dichroic dyes of yellow, magenta and cyan are provided between a pair of electrode substrates 50, respectively. A method of laminating layers and driving them independently has been proposed (Patent Publication 1). However, in this method, in order to drive independently, it is necessary to form a through hole or the like, and there is a problem that the manufacturing process becomes complicated and the cost increases. On the other hand, as shown in FIG. 4, there is also an element in which liquid crystal layers 52 ′, 54 ′ and 56 ′ each containing red, green and blue dichroic dyes are juxtaposed between a pair of electrode substrates 50 ′. It has been proposed (Patent Publication 2). The structure of the element shown in FIG. 4 is relatively simple and can reduce costs. However, when color display is performed, when displaying black, each color (yellow, magenta, cyan, red, green, There is a problem in display performance that the color density of blue) is reduced. In the electrophoresis system, as shown in FIG. 5, an element having a configuration in which microcapsules 62 including white fine particles 58, black fine particles 60, and a dispersion medium 62 are arranged in parallel between a pair of electrode substrates 50 ″. In this method, display is performed by moving the white fine particles 58 in the vertical direction by electrophoresis.

Some methods combining the guest-host method and the electrophoresis method have also been proposed (Patent Documents 4 and 5). However, in any of the systems, satisfactory display performance has not yet been obtained, and improvement has been demanded.
Japanese Patent Laid-Open No. 11-265157 Japanese Patent Laid-Open No. 9-244070, Example 7, FIG. JP 2003-140200 A JP 2003-280047 A JP 2002-277906 A

  An object of the present invention is to provide a liquid crystal composition useful for producing a liquid crystal device having high color display performance, and a liquid crystal device having high visibility and high color display performance.

In a reflective display element combining a guest host method and an electrophoresis method, it is important that the order parameter of the dichroic dye to be used is high. Therefore, the present inventor has intensively studied from the viewpoint of giving a high order parameter as a dichroic dye for a guest-host system, and in this system, the adsorption of the dichroic dye to charged particles is on a white background. The present inventors have found a problem that the reflectance is lowered, that is, the display performance is deteriorated. Furthermore, when the dichroic dye is repeatedly used, a part of the dichroic dye is decomposed, and the decomposition product changes the charging characteristics of the charged particles to deteriorate the display performance.
And when this inventor uses the dichroic dye which has a specific substitution mode, adsorption | suction to the charged particle of a dichroic dye is suppressed, and also when it uses repeatedly, decomposition | disassembly of a dichroic dye The present inventors have obtained the knowledge that an unexpected effect that the deterioration of the display performance is small and the display performance is suppressed, and the present invention has been completed by further studying based on this knowledge.

Means for solving the above-mentioned problems are as follows.
[1] A liquid crystal composition comprising at least one liquid crystal, at least one charged particle, and at least one dichroic dye, wherein the dichroic dye is represented by the following general formula (1). A liquid crystal composition which is a dye having a substituent.
General formula (1)
_{- (Het) j - {(} B 1) p - (Q 1) q - (B 2) r} n -C 1
(In the formula, Het is an oxygen atom or a sulfur atom, B ¹ and B ² each represent a divalent arylene group, a heteroarylene group, or a cyclic aliphatic hydrocarbon group, and Q ¹ represents a divalent linking group. , C ¹ represents an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an acyl group or an acyloxy group, j represents 0 or 1, p, q and r each represent a number of 0 to 5, n Represents a number of 1 to 3, the sum of the numbers of B ¹ and B ^{2 is} a number of 3 to 10, and when p, q and r are each 2 or more, 2 or more of B ¹ , Q ¹ and B ² may be the same or different, and when n is 2 or more, {(B ¹ ) _p − (Q ¹ ) _q − (B ² ) _r } may be the same or different when 2 or more.
[2] The liquid crystal composition according to [1], wherein the dichroic dye is a compound represented by the following general formula (2).

R ¹ is a substituent represented by -S-{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r } _n -C ¹ . Here, S is a sulfur atom, and B ¹ , B ² , Q ¹ , p, q, r, and n have the same definitions as those in the general formula (1) described in claim 2. R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each a hydrogen atom or a substituent.

[3] The liquid crystal composition according to [1] or [2], wherein the dichroic dye is a compound represented by the following general formula (3).

式中、Ｒ¹¹、Ｒ¹²、Ｒ¹³、Ｒ¹⁴、Ｒ¹⁵、Ｒ¹⁶およびＲ¹⁷は各々水素原子または置換基であるが、少なくとも一つ以上は、−Ｓ−｛（Ｂ¹）_p−（Ｑ¹）_q−（Ｂ²）_r｝_n−Ｃ¹で表される置換基である。ここで、Ｓは硫黄原子であり、Ｂ¹、Ｂ²、Ｑ¹、ｐ、ｑ、ｒ、ｎは、［２］中に記載の一般式（１）中のそれぞれと同定義である。

In the formula, each of R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ is a hydrogen atom or a substituent, and at least one of them is —S — {(B ¹ ) _p —. (Q ¹ ) _q — (B ² ) _r } _n is a substituent represented by C ¹ . Here, S is a sulfur atom, and B ¹ , B ² , Q ¹ , p, q, r, and n have the same definitions as in general formula (1) described in [2].

[4] The liquid crystal composition according to any one of [1] to [3], wherein the charged particles are titanium oxide.
[5] The liquid crystal composition according to any one of [1] to [4], wherein the liquid crystal, the dichroic dye, and the charged particles are encapsulated in a microcapsule.
[6] The liquid crystal composition according to any one of [1] to [5], wherein the colors of the dichroic dye and the charged particles have a complementary color relationship.
[7] The liquid crystal composition according to [6], further comprising charged particles having a charge opposite to that of the charged particles and having a different color.
[8] A liquid crystal element having a pair of electrodes, at least one of which is a transparent electrode, and a liquid crystal layer between the pair of electrodes, wherein the liquid crystal layer is any one of [1] to [7] A liquid crystal element, which is a layer containing
[9] The liquid crystal layer contains a plurality of microcapsules containing a dichroic dye that develops red, a microcapsule that contains a dichroic dye that develops green, and a dichroic dye that develops blue [7] The liquid crystal element according to [7], wherein each of the microcapsules to be arranged is arranged in layers.

  A liquid crystal element containing the liquid crystal composition of the present invention exhibits high visibility, display contrast, and high stability in which deterioration of display performance when repeatedly used is suppressed.

BEST MODE FOR CARRYING OUT THE INVENTION

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

The liquid crystal composition of the present invention contains at least one kind of charged particle and at least one kind of dichroic dye. Hereinafter, various materials used in the present invention will be described.
In the present invention, the dichroic dye is defined as a compound that dissolves in the host liquid crystal and has a function of absorbing light. The dichroic dye of the present invention may have any absorption maximum and absorption band, but has an absorption maximum in the yellow region (Y), magenta region (M), or cyan region (C). The case is preferred. Two or more dichroic dyes may be used, and it is preferable to use a mixture of dichroic dyes having absorption maxima in Y, M, and C. The method of performing full color display by mixing a yellow dye, a magenta dye, and a cyan dye is detailed in “Color Chemistry” (written by Sumio Tokita, Maruzen, 1982). Here, the yellow region is a range of 430 to 490 nm, the magenta region is a range of 500 to 580 nm, and the cyan region is a range of 600 to 700 nm.

Next, the chromophore used for the dichroic dye of the present invention will be described.
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, Examples include phenoxazine 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 of a monoazo dye, a bisazo dye, a trisazo dye, a tetrakisazo dye, a pentakisazo dye, and 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.

The dichroic dye of the present invention preferably has a substituent represented by the following general formula (1).
General formula (1)
_{- (Het) j - {(} B 1) p - (Q 1) q - (B 2) r} n -C 1
In the formula, Het is an oxygen atom or a sulfur atom, B ¹ and B ² each represent an arylene group, a heteroarylene group, or a divalent cyclic aliphatic hydrocarbon group, Q ¹ represents a divalent linking group, C ¹ represents an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group or an acyloxy group. j represents 0 or 1, p, q and r each represents a number from 0 to 5, n represents a number from 1 to 3, and the sum of the numbers of B ¹ and B ² is 3 or more and 10 or less Is a number. When p, q and r are each 2 or more, 2 or more B ¹ , Q ¹ and B ² may be the same or different, and when n is 2 or more, 2 or more {(B ¹ ) _p − (Q ¹ ) _q − (B ² ) _r } may be the same or different.

Het is an oxygen atom or a sulfur atom, particularly preferably a sulfur atom.
B ¹ and B ² each represent an arylene group, a heteroarylene group, or a divalent cyclic aliphatic hydrocarbon group. The arylene group, heteroaryllene group and divalent cyclic aliphatic hydrocarbon group represented by B ¹ and B ² include an arylene group having a substituent, a heteroarylene group and a divalent cyclic aliphatic hydrocarbon group. .

The divalent arylene group is preferably an arylene group having 6 to 20 carbon atoms, and specific examples of the preferred arylene group include a benzene ring, a naphthalene ring, and an anthracene ring group. Particularly preferred are benzene ring and substituted benzene ring groups, and more preferred is a 1,4-phenylene group. The divalent heteroarylene group represented by B ¹ and B ² is preferably a heteroarylene group having 1 to 20 carbon atoms, and is a pyridine ring, quinoline ring, isoquinoline ring, pyrimidine ring, pyrazine ring, thiophene ring, furan ring. , An oxazole ring, a thiazole ring, an imidazole ring, a pyrazole ring, an oxadiazole ring, a thiadiazole ring and a triazole ring, and a condensed heteroarylene group formed by condensing them. The divalent cyclic hydrocarbon group represented by B ¹ and B ² is preferably a cyclohexane-1,2-diyl group, a cyclohexane-1,3-diyl group, a cyclohexane-1,4-diyl group, a cyclopentane- A 1,3-diyl group, particularly preferably (E) -cyclohexane-1,4-diyl group.

The arylene group, heteroarylene group and divalent cyclic hydrocarbon group represented by B ¹ and B ² may further have a substituent, and examples of the substituent 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 carbon atoms, preferably 2 to 8 carbon atoms, and more preferably 2 to 5 carbon atoms (for example, methylsulfamoyl group). , Ethylsulfamoyl, piperidinosulfonyl), a nitro group, an alkoxy group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms (for example, methoxy, ethoxy, 2-methoxyethoxy). , 2-phenylethoxy), carbon number 6-20, preferably carbon number 6-12, more preferably carbon number -10 aryloxy groups (for example, phenoxy, p-methylphenoxy, p-chlorophenoxy, naphthoxy), C1-20, preferably C2-12, more preferably C2-8 acyl groups (for example, Acetyl, benzoyl, trichloroacetyl), C1-20, preferably C2-12, more preferably C2-8 acyloxy groups (eg acetyloxy, benzoyloxy), C1-20, preferably C2-C12, more preferably C2-C8 acylamino group (for example, acetylamino), C1-C20, preferably C1-C10, more preferably C1-C8 sulfonyl group (for example, Methanesulfonyl, ethanesulfonyl, benzenesulfonyl), 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, Preferably, the sulfinyl group having 1 to 8 carbon atoms (for example, methanesulfinyl, ethanesulfinyl, benzenesulfinyl), 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms substituted or unsubstituted Amino groups such as 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-trifluoromethylphenylamino, 4-trifluoromethylphenylamino, 2-pyridylamino , 3-pyridylamino, 2-thiazolyl Mino, 2-oxazolylamino, N, N-methylphenylamino, N, N-ethylphenylamino), ammonium having 0 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 6 carbon atoms. A group (eg trimethylammonium, triethylammonium), 0-15 carbon atoms, preferably 1-10 carbon atoms, more preferably a hydrazino group having 1-6 carbon atoms (eg trimethylhydrazino group), 1-15 carbon atoms, preferably Is a ureido group having 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms (eg ureido group, N, N-dimethylureido group), 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, more preferably carbon. An imide group having 1 to 6 carbon atoms (for example, a succinimide group), an alkyl group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, and more preferably 1 to 8 carbon atoms. A group (for example, methylthio, ethylthio, propylthio), an arylthio group having 6 to 80 carbon atoms, preferably 6 to 40 carbon atoms, more preferably 6 to 30 carbon atoms (for example, phenylthio, p-methylphenylthio, p-chlorophenylthio, 2-pyridylthio, 1-naphthylthio, 2-naphthylthio, 4-propylcyclohexyl-4′-biphenylthio, 4-butylcyclohexyl-4′-biphenylthio, 4-pentylcyclohexyl-4′-biphenylthio, 4-propylphenyl- 2-ethynyl-4′-biphenylthio), a heteroarylthio group having 1 to 80 carbon atoms, preferably 1 to 40 carbon atoms, more preferably 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 carbon atoms, preferably 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms (for example, methoxycarbonyl, ethoxycarbonyl, 2-benzyloxycarbonyl), 6 to 20 carbon atoms, preferably Is an aryloxycarbonyl group having 6 to 12 carbon atoms, more preferably 6 to 10 carbon atoms (for example, phenoxycarbonyl), 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms. A substituted alkyl group (for example, methyl, ethyl, propyl, butyl), a substituted alkyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms {for example, hydroxymethyl, trifluoromethyl, benzyl , Carboxyethyl, ethoxycarbonylmethyl, acetylaminomethyl, and also here having 2 to 1 carbon atoms An unsaturated hydrocarbon group having 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms (for example, vinyl group, ethynyl group 1-cyclohexenyl group, benzylidine group, benzylidene group) is also included in the substituted alkyl group. A substituted or unsubstituted aryl group having 6 to 20 carbon atoms, preferably 6 to 15 carbon atoms, more preferably 6 to 10 carbon atoms (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-pentylcyclohexyl-4′-biphenyl, 4-propylphenyl-2-ethynyl-4′-biphenyl), carbon number 1-20, preferably carbon number 10, further preferably a substituted or unsubstituted heteroaryl group having 4 to 6 carbon atoms (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. Furthermore, the substituent shown in the explanation of V explained so far may be further substituted on these substituents.

  Preferred as the substituent group V are the aforementioned alkyl group, aryl group, alkoxy group, aryloxy group, halogen atom, amino group, substituted amino group, hydroxy group, alkylthio group, and arylthio group, and more preferably alkyl group. A group, an aryl group, and a halogen atom.

Q ¹ represents a divalent linking group. Preferably, it is a linking group comprising an atomic group composed of at least one atom selected from a carbon atom, a nitrogen atom, a sulfur atom and an oxygen atom. Examples of the divalent linking group represented by Q ¹ include an alkylene group having 1 to 20 carbon atoms (for example, methylene, ethylene, propylene, butylene, pentylene, cyclohexyl-1,4-diyl), and an alkenylene group having 2 to 20 carbon atoms. (For example, ethenylene), C2-C20 alkynylene group (for example, ethynylene), amide group, ether group, ertel group, sulfoamide group, sulfonate group, ureido group, sulfonyl group, sulfinyl group, thioether group, carbonyl One group, -NR- group (where R represents a hydrogen atom, an alkyl group or an aryl group), an azo group, an azoxy group, or a heterocyclic divalent group (for example, piperazine-1,4-diyl group). Alternatively, a divalent linking group having 0 to 60 carbon atoms constituted by a combination thereof may be used. The divalent linking group represented by Q ¹ is preferably an alkylene group, an alkenylene group, an alkynylene group, an ether group, a thioether group, an amide group, an ertel group, a carbonyl group, or a combination thereof. Q ¹ may further have a substituent, and examples of the substituent include the substituent group V described above.

C ¹ represents an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an acyl group or an acyloxy group. The alkyl group, cycloalkyl group, alkoxy group, alkoxycarbonyl group, acyl group or acyloxy group represented by C ¹ includes each group having a substituent. C ¹ is preferably an alkyl or cycloalkyl group having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, still more preferably 1 to 8 carbon atoms (for example, methyl, ethyl, propyl, butyl, t-butyl, i -Butyl, sec-butyl, pentyl, t-pentyl, hexyl, heptyl, octyl, cyclohexyl, 4-methylcyclohexyl, 4-ethylcyclohexyl, 4-propylcyclohexyl, 4-butylcyclohexyl, 4-pentylcyclohexyl, hydroxymethyl, tri Fluoromethyl, benzyl), an alkoxy group having 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, still more preferably 1 to 8 carbon atoms (for example, methoxy, ethoxy, 2-methoxyethoxy, 2-phenylethoxy), carbon 1 to 20, more preferably 2 to 12 carbon atoms, still more preferably Or an acyloxy group having 2 to 8 carbon atoms (for example, acetyloxy, benzoyloxy), 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and still more preferably an acyl group having 1 to 8 carbon atoms (for example, acetyl, formyl). , Pivaloyl, 2-chloroacetyl, stearoyl, benzoyl, pn-octyloxyphenylcarbonyl), or an alkoxycarbonyl group having 2 to 20, more preferably 2 to 12, more preferably 2 to 8 carbon atoms. (For example, methoxycarbonyl, ethoxycarbonyl, 2-benzyloxycarbonyl). C ¹ is particularly preferably an alkyl group or an alkoxy group, and more preferably an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group or a trifluoromethoxy group. C ¹ may further have a substituent, and examples of the substituent include the substituent group V described above.

j represents 0 or 1, preferably 0.
p, q and r each represent a number of 0 to 5, n represents a number of 1 to 3, and the sum of the numbers of B ¹ and B ^{2 is} a number of 3 or more and 10 or less. In addition, when p, q, r, and n are 2 or more, the repeating unit may be the same or different. Preferred combinations of p, q, r and n are described below.
(I) p = 3, q = 0, r = 0, n = 1
(Ii) p = 4, q = 0, r = 0, n = 1
(Iii) p = 5, q = 0, r = 0, n = 1
(Iv) p = 2, q = 0, r = 1, n = 1
(V) p = 2, q = 1, r = 1, n = 1
(Vi) p = 1, q = 1, r = 2, n = 1
(Vii) p = 3, q = 1, r = 1, n = 1
(Viii) p = 2, q = 0, r = 2, n = 1
(Ix) p = 1, q = 1, r = 1, n = 2
(X) p = 2, q = 1, r = 1, n = 2

  Particularly preferably, (i) p = 3, q = 0, r = 0, n = 1; (iv) p = 2, q = 0, r = 1, n = 1; and (v) p = 2, The combination is q = 1, r = 1, n = 1.

Note that-{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r } _n -C ¹ preferably includes a partial structure exhibiting liquid crystallinity. The liquid crystal herein may be in any phase, but is preferably a nematic liquid crystal, a smectic liquid crystal, or a discotic liquid crystal, and particularly preferably a nematic liquid crystal.

Specific examples of-{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r } _n -C ¹ are shown below, but the present invention is not limited to this (in the figure, wavy lines are Represents the connection position).

The dichroic dye used in the present invention, - that has a substituent 1 or more represented by _{^{{(B 1) p - -}} (Q 1) q (B 2) r} n -C 1 It is preferably 1-8, more preferably 1-4, particularly preferably 1 or 2.

In a preferred structure of the substituent represented by the general formula (1), Het is a sulfur atom, B ¹ represents an arylene group or a heteroarylene group, B ² represents a cyclohexane-1,4-diyl group, A structure in which C ¹ represents an alkyl group, j = 1, p = 2, q = 0, r = 1 and n = 1; and Het is a sulfur atom, B ¹ represents an arylene group or a heteroarylene group B ² represents a cyclohexane-1,4-diyl group, C ¹ represents an alkyl group, and j = 1, p = 1, q = 0, r = 2 and n = 1. Particularly preferred structures are that Het represents a sulfur atom, B ¹ represents a 1,4-phenylene group, B ² represents a trans-cyclohexyl group, and C ¹ represents an alkyl group (preferably a methyl group, an ethyl group, a propyl group). , A butyl group, a pentyl group or a hexyl group), and a structure represented by the following general formula (a-1) wherein j = 1, p = 2, q = 0, r = 1 and n = 1; and Het Represents a sulfur atom, B ¹ represents a 1,4-phenylene group, B ² represents a trans-cyclohexane-1,4-diyl group, and C ¹ represents an alkyl group (preferably a methyl group, an ethyl group, a propyl group). , A butyl group, a pentyl group, or a hexyl group), and a structure represented by the following general formula (a-2) in which j = 1, p = 1, q = 0, r = 2, and n = 1. .

In the general formulas (a-1) and (a-2), R ^{a1 to} R ^a12 each independently represent a hydrogen atom or a substituent. Examples of the substituent include a substituent selected from the aforementioned substituent group V. R ^{a1 to} R ^a12 are each preferably a hydrogen atom, a halogen atom (particularly a fluorine atom), an alkyl group, an aryl group, or an alkoxy group.
In the general formulas (a-1) and (a-2), C ^a1 and C ^a2 each independently represent an alkyl group, preferably a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or hexyl. Represents a group.

  In addition, as a dichroic dye used for this invention, the compound represented by following General formula (2) or (3) is preferable.

In the formula, R ¹ is a substituent represented by —S — {(B ¹ ) _p — (Q ¹ ) _q — (B ² ) _r } _n —C ¹ . Here, S is a sulfur atom, B ¹ , B ² , Q ¹ , p, q, r, and n have the same definitions as those described above, and the preferred ranges are also the same. R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each a hydrogen atom or a substituent.

In the formula, each of R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ is a hydrogen atom or a substituent, and at least one of them is —S — {(B ¹ ) _p —. (Q ¹ ) _q — (B ² ) _r } _n is a substituent represented by C ¹ . Here, S is a sulfur atom, and B ¹ , B ² , Q ¹ , p, q, r, and n have the same definitions as those in the general formula (1), and preferred ranges are also the same.

Examples of the substituent represented by R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ include the above substituent group V, preferably 6 to 80 carbon atoms, more preferably Is an arylthio group having 6 to 40 carbon atoms, more preferably 6 to 30 carbon atoms (for example, phenylthio, p-methylphenylthio, p-chlorophenylthio, 4-methylphenylthio, 4-ethylphenylthio, 4-n-propyl). Phenylthio, 2-n-butylphenylthio, 3-n-butylphenylthio, 4-n-butylphenylthio, 2-t-butylphenylthio, 3-t-butylphenylthio, 4-t-butylphenylthio 3-n-pentylphenylthio, 4-n-pentylphenylthio, 4-amylpentylphenylthio, 4-hexylphenylthio, 4-heptylphenylthio, 4-o Cutylphenylthio, 4-trifluoromethylphenylthio, 3-trifluoromethylphenylthio, 2-pyridylthio, 1-naphthylthio, 2-naphthylthio, 4-propylcyclohexyl-4′-biphenylthio, 4-butylcyclohexyl-4 ′ -Biphenylthio, 4-pentylcyclohexyl-4'-biphenylthio, 4-propylphenyl-2-ethynyl-4'-biphenylthio), 1 to 80 carbon atoms, more preferably 1 to 40 carbon atoms, still more preferably carbon Heteroarylthio groups of 1 to 30 (for example, 2-pyridylthio, 3-pyridylthio, 4-pyridylthio, 2-quinolylthio, 2-furylthio, 2-pyrrolylthio), substituted or unsubstituted alkylthio groups (for example, methylthio, ethylthio, Butylthio, phenethylthio), substituted Or an unsubstituted amino group (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-trifluoromethylphenylamino, 4-trifluoromethylphenyl Amino, 2-pyridylamino, 3-pyridylamino, 2-thiazolylamino, 2-oxazolylamino, N, N-methylphenylamino, N, N-ethylphenylamino), halogen atoms (for example, fluorine atom, chlorine atom), Substituted or unsubstituted alkyl groups (eg, methyl , Trifluoromethyl), substituted or unsubstituted alkoxy groups (eg, methoxy, trifluoromethoxy), substituted or unsubstituted aryl groups (eg, phenyl), substituted or unsubstituted heteroaryl groups (eg, 2-pyridyl) ), A substituted or unsubstituted aryloxy group (for example, phenoxy), a substituted or unsubstituted heteroaryloxy group (for example, 3-thienyloxy), and the like.

R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are preferably hydrogen atom, fluorine atom, chlorine atom, substituted or unsubstituted arylthio group, alkylthio group, amino group, alkylamino Group, arylamino group, alkyl group, aryl group, alkoxy group or aryloxy group, particularly preferably a hydrogen atom, a fluorine atom, a substituted or unsubstituted arylthio group, an alkylthio group, an amino group, an alkylamino group or an arylamino group It is a group.

Examples of the substituent represented by R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ include a halogen atom, alkyl group, aryl group, alkylthio group, arylthio group, heterocyclic thio group, hydroxyl group Group, alkoxy group, aryloxy group, carbamoyl group, acyl group, aryloxycarbonyl group, alkoxycarbonyl group, and amide group, particularly preferably a hydrogen atom, a halogen atom, an alkyl group, an arylthio group, and an amide group.

R ¹⁶ is preferably an amino group (including alkylamino and arylamino groups), a hydroxyl group, a mercapto group, an alkylthio group, an arylthio group, an alkoxy group or an aryloxy group, and particularly preferably an amino group.

  Although the specific example of the dichroic dye which can be used for this invention below is shown, this invention is not limited at all by the following specific examples.

  Specific examples of dioxazine dichroic dyes and merocyanine dichroic dyes that can be used in the present invention are shown below, but the present invention is not limited to the following specific examples.

  The dichroic dye having a substituent represented by the general formula (1) can be synthesized by combining known methods. For example, it can be synthesized according to the method described in JP-A No. 2003-192664.

The charged particles used in the present invention are not particularly limited with respect to the material thereof, and inorganic particles such as silica, alumina, zirconia, titanium oxide, tungsten oxide, zinc oxide, tin oxide, barium titanate may be used, or Organic particles such as polymer and carbon black may be used. The white charged particles are preferably charged particles made of titanium oxide, silica gel (SiO ₂ ), alumina, and polymer particles, and the black charged particles are preferably charged particles made of carbon black. In addition, the particle size of the charged particles is preferably 100 μm or less, and more preferably 0.1 to 10 μm.
The surface is preferably modified for the purpose of enhancing the dispersion stability of the charged particles in the dispersion medium. Surface modification methods include titanium coupling agents (such as isopropyl triisostearoyl titanate), silane coupling agents (such as pentadecafluorodecyltrimethylsilane), aluminum coupling agents (such as acetoalkoxyaluminum diisopropylate), and grafts. Polymerization etc. are mentioned. As the graft polymerization, polyethylene graft polymerization and polystyrene graft polymerization can be used for titanium oxide, and graft polymerization using silanol groups can be used for silica gel.

  In particular, in the present invention, since the liquid crystal compound is used as the dispersion medium, it is preferable to modify the surface of the charged particle with a surface modifier that increases the affinity with the liquid crystal compound. In order to increase the affinity with a liquid crystal compound, a structure having both a partial structure exhibiting liquid crystallinity and a site that forms a covalent bond with a charged particle is preferable. The partial structure exhibiting liquid crystallinity is preferably represented by the above general formula of the present invention. Examples include the structure represented by (1).

  The host liquid crystal usable in the liquid crystal element of the present invention has a function of changing the alignment state by the action of an electric field and controlling the alignment state of the dichroic dye dissolved as a guest, and is charged A compound having a function of stably dispersing particles, changing the position of charged particles by the action of an electric field by electrophoresis, and controlling the particles is preferable.

  The host liquid crystal usable in the liquid crystal composition of the present invention is not particularly limited as long as it can coexist with the compound of the present invention. For example, a liquid crystal compound exhibiting a nematic phase or a smectic phase can be used. Specific examples thereof 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 phenylpyrimidines, Fluorine-substituted phenylpyrimidine, alkoxy-substituted phenylpyrimidine, fluorine-substituted alkoxy-substituted phenylpyrimidine, phenyldioxane, tolan compounds, fluorine-substituted tolan compounds, alkenylcyclohexylbenzonitrile and the like. 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. It is also possible to use a fluorine-substituted host liquid crystal suitable for TFT driving. 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.).

  The dielectric anisotropy of the host liquid crystal used in the present invention may be positive or negative. When the host liquid crystal having positive dielectric anisotropy is horizontally aligned, the liquid crystal is horizontally aligned when no voltage is applied, so that the dichroic dye also becomes horizontal and absorbs light. On the other hand, since the liquid crystal molecules tilt vertically when a voltage is applied, the dichroic dye also tilts vertically, and as a result, light is transmitted. That is, the mode is such that white display is performed when a voltage is applied, and black display is performed when no voltage is applied. When the host liquid crystal having a negative dielectric anisotropy is vertically aligned, when no voltage is applied, the liquid crystal is vertically aligned, so that the dichroic dye is also vertical and transmits without absorbing light. On the other hand, since the liquid crystal molecules tilt horizontally when a voltage is applied, the dichroic dye also tilts horizontally, and as a result, absorbs light. That is, the mode is such that white display is performed when no voltage is applied, and black display is performed when a voltage is applied. In order to obtain a liquid crystal having a negative dielectric anisotropy, it is necessary to have a structure in which the dielectric anisotropy is large on the short axis of the liquid crystal molecule. For example, “Monthly Display” (2000, 4 (Month issue), pages 4-9, Synlett. Vol.4, pages 389 to 396, 1999. Among these, from the viewpoint of voltage holding ratio, a liquid crystal having a fluorine-containing substituent and having a negative dielectric anisotropy is preferable. For example, Merck liquid crystal (MLC-6608, 6609, 6610, etc.) can be mentioned.

  In the present invention, for the purpose of changing the physical properties of the host liquid crystal to a desired range (for example, for the purpose of setting the temperature range of the liquid crystal phase to a desired range), a compound that does not exhibit liquid crystal properties may be added. Good. Moreover, you may contain compounds, such as a chiral compound, a ultraviolet absorber, and antioxidant. Examples of such additives include chiral agents for TN and STN described in pages 199 to 202 of “Liquid Crystal Device Handbook” (edited by the Japan Society for the Promotion of Science 142nd Committee, Nikkan Kogyo Shimbun, 1989). It is done.

  Although there is no restriction | limiting in particular about content of a host liquid crystal and a dichroic dye in the liquid-crystal composition of this invention, Content of a dichroic dye is 0.1-15 mass% with respect to content of a host liquid crystal. It is preferable that it is 0.5 to 6% by mass. In addition, the content of the host liquid crystal and the dichroic dye is adjusted to a liquid crystal composition containing both, and the absorption spectrum of the liquid crystal cell in which the liquid crystal composition is sealed is measured to obtain a desired optical density as the liquid crystal cell. It is desirable to determine the dye concentration required to indicate Also, the content of charged particles in the liquid crystal composition of the present invention is preferably in a range of 10 to 90% by mass in the composition, although the preferred range varies depending on the use and materials used. More preferably, it is 10-50 mass%.

  The liquid crystal composition of the present invention can be used for manufacturing a liquid crystal element in a state of being encapsulated in a microcapsule. Usable microcapsule walls include cross-linked gelatin, alginate, cellulose, urethane resin, melamine resin, nylon resin, styrene resin, urea resin, acrylate ester resin, methacrylate ester resin, acrylamide resin and fumarate ester resin, etc. Various things can be used. Preferred are styrene resin, urea resin, acrylate ester resin, methacrylate ester resin, acrylamide resin, and fumarate ester resin. The microcapsule wall may be made of a resin having a crosslinked structure. The resin having a crosslinked structure is obtained by irradiating a copolymer obtained by copolymerizing a crosslinking precursor monomer such as N-hydroxymethylacrylamide and N-alkoxymethylacrylamide with heat, ultraviolet rays or radiation. Can be produced. Moreover, it can also manufacture by copolymerizing a polyfunctional monomer (For example, N, N'-methylenebis (meth) acrylamide, bishydroxyethyl (meth) acrylate, divinylbenzene, etc.). The amount of the crosslinking agent (crosslinking precursor monomer in the former production example and polyfunctional monomer in the latter production example) is not particularly limited, but is preferably 0.0001 to 40 with respect to the monomer. The mol%, more preferably 0.01 to 30 mol%, still more preferably 1 to 20 mol%.

  Microcapsules containing a host liquid crystal, a dichroic dye and charged particles can be produced by various methods. For example, a host liquid crystal, a dichroic dye and charged particles are mixed, and a monomer capable of forming a wall is added thereto. If necessary, an organic solvent may be further added. Examples of organic solvents that can be added include aromatic solvents (benzene, alkylbenzene, alkylnaphthalene, alkylbiphenyl, etc.), hydrocarbon solvents (hexane, octane, etc.), halogenated hydrocarbon solvents (methylene chloride, chloroform, dichloroethane). Etc.), ester solvents (ethyl acetate, adipate, fumarate, carbonate, etc.), ether solvents (diethyl ether, tetrahydrofuran, etc.), amide solvents, sulfoxide solvents, nitrile solvents (acetonitrile, etc.) ), Ketone solvents (acetone and the like), and the like. You may use these in mixture of 2 or more types.

  Next, these mixtures are dispersed in the aqueous phase as oil droplets. A dispersant may be added to the aqueous phase. For example, any of a polymer dispersant, an inorganic dispersant, a surfactant, and the like can be used. Examples of the polymer dispersant include polyvinyl alcohol and gelatin. Examples of the inorganic dispersant include calcium phosphate, potassium sulfate, silica, alumina, and hydroxyapatite. Examples of the surfactant include sodium dodecylbenzene sulfate, sodium laurate, sodium stearate and the like. Any method may be used for dispersing the mixture as oil droplets in the aqueous phase. For example, a homogenizer, a dispersion media, an ultrasonic disperser, a membrane emulsifier, or the like can be used. Examples of the dispersion media include a sand mill, a ball mill, an attritor, a triple roll, a basket mill, and a disperser. Preferred dispersing methods are a homogenizer, a ball mill, an ultrasonic disperser, and a membrane emulsifier.

  The form of the microcapsule wall may be formed by any method. Examples of the chemical method include an interfacial polymerization method, an in-situ polymerization method, a liquid curing coating method, and the like. Examples thereof include a separation method, a liquid drying method, a melt dispersion cooling method, and an air suspension coating method. The interfacial polymerization method and the in-situ polymerization method are preferable.

  The liquid crystal element of the present invention is a liquid crystal element provided with a liquid crystal layer containing the liquid crystal composition of the present invention. The liquid crystal element of the present invention comprises, for example, a pair of electrode substrates (at least one is preferably a transparent electrode substrate) and a liquid crystal layer containing the liquid crystal composition of the present invention sandwiched between the pair of electrode substrates. can do. As the electrode substrate, a substrate in which an electrode layer is formed on a substrate usually made of glass or plastic can be used. 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” (Japan Society for the Promotion of Science 142nd edition, Nikkan Kogyo Shimbun, 1989) can be used. The electrode layer formed on the substrate is preferably a transparent electrode layer, and at least the electrode on the display surface side is preferably a transparent electrode. For example, it can be formed from indium oxide, indium tin oxide (ITO), tin oxide, or the like. 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.

  The liquid crystal element of the present invention can be produced, for example, by placing a pair of substrates facing each other at intervals of 1 to 50 μm via a spacer and arranging the liquid crystal composition of the present invention in a space formed between the substrates. it can. 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. The liquid crystal composition of the present invention can be disposed in a space between substrates by coating or printing on the substrates.

The liquid crystal element of the present invention can be driven by a simple matrix driving method or an active matrix driving method 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 Japan Society for the Promotion of Science 142nd Committee, Nikkan Kogyo Shimbun, 1989). Available as a method.
In order to perform electrophoresis of charged particles, a driving method in which a DC voltage is applied is preferable. In order to control the orientation of the dichroic dye, a driving method in which an alternating voltage is applied is preferable.

  A plurality of dichroic dyes that develop colors different from each other may be mixed in the liquid crystal composition of the present invention. Further, a plurality of charged particles that develop colors different from each other and / or have opposite charges may be mixed. The color of the liquid crystal composition may be anything. For example, when a black liquid crystal composition is prepared by using a mixture of a plurality of dichroic dyes or a plurality of charged particles that develop colors different from each other, a display element that becomes black and white when a voltage is applied Can be used as

A typical example of the color display method will be described below.
A schematic cross-sectional view of one embodiment of the liquid crystal element of the present invention is shown in FIG. The liquid crystal element shown in FIG. 1 is a negatively charged white charged particle composed of a liquid crystal 14, a black dichroic dye 16 oriented in the same direction as the molecules of the liquid crystal 14, and titanium oxide between a pair of substrates 10. In this configuration, a plurality of microcapsules 12 including 18 are arranged. A transparent electrode (not shown) is formed on the opposite surface of the substrate 10 so that a DC voltage sufficient for the white charged particles 18 to electrophore and an AC voltage sufficient for aligning the liquid crystal 14 can be applied. It is configured.
In the case of white display, a DC voltage is applied so that the transparent electrode on the display side serves as an anode, and the white charged particles 18 are electrophoresed above the microcapsules 12. In the case of black display, a DC voltage is applied so that the transparent electrode on the display side becomes a cathode, and the white charged particles 18 are electrophoresed below the microcapsules 12, and then an AC voltage is applied so The chromatic dye 16 is aligned with the liquid crystal 14 in the horizontal direction. When the dielectric anisotropy of the liquid crystal 14 is negative, the black dichroic dye 16 can be arranged in the horizontal direction by applying an alternating voltage.

  In the above embodiment, an example of black and white image display using a black dye as a dichroic dye has been shown. For example, a microscopic image containing a plurality of dichroic dyes that develop red, a host liquid crystal, and black charged particles. Each of a capsule, a microcapsule containing a green dichroic dye, a host liquid crystal and black charged particles, and a microcapsule containing a blue dichroic dye, a host liquid crystal and black charged particles, In a liquid crystal element having a configuration in which layers are arranged in parallel (for example, the same arrangement as in FIG. 4), full color display by subtractive color mixing is possible. Printing technology may be used to arrange the microcapsules in parallel.

  A schematic cross-sectional view of another embodiment of the liquid crystal element of the present invention is shown in FIG. The liquid crystal element shown in FIG. 2 has a negatively charged white color composed of a liquid crystal 14, a magenta dichroic dye 16 ′ aligned in the same direction as the molecules of the liquid crystal 14, and titanium oxide between a pair of substrates 10 ′. In this configuration, a plurality of compositions containing charged particles 18 and positively charged green (magenta complementary color) charged particles 18 ′ are arranged in parallel, separated by partition walls 20. Transparent electrodes 21, 22 and 23 are respectively formed on the opposing surfaces of the pair of substrates 10 ′ and the surfaces contacting the composition of the partition wall 20, and a DC voltage sufficient for the charged particles 18 and 18 ′ to perform electrophoresis. And an alternating voltage sufficient to orient the liquid crystal 14 can be applied. In this embodiment, the colors of the dichroic dye 16 'and the positively charged charged particles 18' are not limited to magenta and green, but they must be complementary colors.

In this embodiment, in the case of white display, the white charged particles 18 are electrophoresed upward by applying a DC voltage so that the transparent electrode 21 on the display side becomes an anode.
In the case of black display, first, a direct current voltage is applied so that the transparent electrode 23 becomes an anode so that the transparent electrode 22 becomes a cathode, and the green charged particles 18 ′ are white charged on the surface of the transparent electrode 22. The particles 18 are moved to the vicinity of the partition wall. Next, the magenta dichroic dye 16 ′ is horizontally oriented by applying an alternating voltage using the transparent electrode 22 and the transparent electrode 21. In this case, the magenta of the dichroic dye 16 ′ and the green of the charged particle 18 ′ absorb both light in a complementary color relationship, so that a black display is obtained.
In the case of magenta display, first, a DC voltage is applied so that the transparent electrode 22 serves as an anode and the transparent electrode 23 serves as a cathode, so that white charged particles 18 are placed on the surface of the transparent electrode 22 and green charged particles. 18 'is moved to the vicinity of the partition wall. Next, the magenta dichroic dye 16 ′ is horizontally oriented by applying an alternating voltage using the transparent electrode 21 and the transparent electrode 22.
In the case of green display, a DC voltage is applied so that the transparent electrode 21 on the display side becomes a cathode, and the green charged particles 18 ′ are electrophoresed upward.

  In the above, a mode in which white, black, magenta, and green can be displayed has been shown, but the present invention is not limited to this mode. For example, the dichroic dye and the charged particles may be in a complementary relationship, or three types of pixels in which the dichroic dye and the charged particles are in a complementary relationship (yellow and blue, magenta and green). , Cyan and red) can be arranged side by side to perform color display.

  The liquid crystal element of the present invention can be suitably used as a display element for computers, watches, calculators and the like.

  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
<Preparation of liquid crystal composition>
1. Preparation of Dichroic Dye Dichroic dyes (1-2) and (1-8) were synthesized according to the method described in JP-A No. 2003-192664. The dichroic dyes (1-11) and (1-12) were synthesized according to the method described in Japanese Patent Application No. 2004-89769. The dichroic dye (1-16) was synthesized according to the method described in Japanese Patent Application No. 2004-50265. Dichroic dyes (Y-1), (M-1), and (C-1) are disclosed in Jpn. J. et al. Appl. Phys. vol. 37, p. 3422, 1998.

2. Preparation of microcapsules Ultrasonic dispersion of 1.0 g of titanium oxide fine particles (manufactured by Ishihara Sangyo) with an average particle diameter of 1.0 μm, 30 mg of dichroic dyes shown in the table below, and 10 ml of host liquid crystal ZLI-2806 (manufactured by Merck) A liquid crystal dispersion was prepared. In this liquid crystal dispersion, 50 mg of polymerization initiator V-65 (2,2′-azobis (2,4-dimethylvaleronitrile), manufactured by Wako Pure Chemical Industries, Ltd.), 1.0 g of 2-methylhexyl methacrylate as a monomer, methyl methacrylate 1 Liquid crystal dispersion droplets having a diameter of about 20 μm were prepared from a liquid crystal solution containing 0.0 g and 0.2 g of diethylene glycol bismethacrylate as a cross-linking agent using an internal pressure type micro kit (MN-20) SPG film emulsifying device manufactured by SPG. . At this time, a polyvinyl alcohol 2% aqueous solution (Kuraray Poval MP-102) was used as a dispersion.

This dispersion was polymerized by heating in a nitrogen atmosphere at 80 ° C. for 5 hours to obtain microcapsules containing a dichroic dye, white charged particles, and a host liquid crystal. The microcapsules were washed with water and then applied to a glass substrate with an ITO transparent electrode using a screen printer in addition to an ethylene glycol aqueous solution. The coated material was heated at 120 ° C. for 2 hours to evaporate the solvent, and then a glass substrate with a counter electrode was placed thereon and sealed with an epoxy resin.
Next, as a comparison, among the above operations, a microcapsule was prepared by the same operation as described above using a liquid crystal composition to which no white charged particles were added to obtain a composition for a comparative example.

3. Evaluation of reflectance On the image display surface side of the produced guest-host reflective liquid crystal display element, the reflectance and contrast ratio on the white display side (when transparent) and the color display side (when colored) are measured by spectrophotometry. It measured using the measuring device (Shimadzu Corporation make, UV-3100PC). A 30 V DC voltage was applied during white display, and an AC voltage of 60 Hz and 20 V was applied during color display. The results are shown in Table 1.

From the results shown in Table 1, it can be seen that the liquid crystal composition of the present invention gives a high contrast ratio. This is because the liquid crystal composition of the present invention has a high order parameter of the dichroic dye and a high reflectance in white display. More specifically, when the dichroic dye has the substituent represented by the general formula (1), it was confirmed that the contrast ratio is particularly high.
In addition, the liquid crystal element of the present invention gave a white background that is gentle to the eyes and has no viewing angle dependency based on scattering. That is, it was confirmed that the liquid crystal element of the present invention does not require a polarizing plate and is a display element with excellent visibility giving a scattered white background similar to paper.

  The liquid crystal composition of the present invention can be widely used for the production of liquid crystal elements, and is particularly preferably used for the production of guest-host liquid crystal display elements. A guest-host type liquid crystal display device manufactured using the liquid crystal composition of the present invention gives high display contrast and is excellent in visibility.

It is a schematic sectional drawing of the one aspect | mode of the liquid crystal element of this invention. It is a schematic sectional drawing of the other aspect of the liquid crystal element of this invention. It is a schematic sectional drawing of an example of the conventional liquid crystal element. It is a schematic sectional drawing of the other example of the conventional liquid crystal element. It is a schematic sectional drawing of the other example of the conventional liquid crystal element.

Explanation of symbols

10, 10 'electrode substrate 12 microcapsule 14 host liquid crystal 16 black dichroic dye 16' magenta dichroic dye 18 white charged particle 18 'green charged particle 20 partition 21, 22, 23 electrode layer 50, 50', 50 " Electrode substrate 52 Yellow liquid crystal layer 52 'Red liquid crystal layer 54 Magenta liquid crystal layer 54' Green liquid crystal layer 56 Cyan liquid crystal layer 56 'Blue liquid crystal layer 58 White fine particles 60 Black fine particles 62 Dispersion medium 64 Microcapsules

Claims (6)

A liquid crystal composition containing at least one liquid crystal, at least one charged particle, and at least one dichroic dye, wherein the dichroic dye is a substituent represented by the following general formula (1) A liquid crystal composition which is a pigment having
General formula (1)
_{- (Het) j - {(} B 1) p - (Q 1) q - (B 2) r} n -C 1
(In the formula, Het is an oxygen atom or a sulfur atom, B ¹ and B ² each represent an arylene group, a heteroarylene group, or a divalent cyclic aliphatic hydrocarbon group, and Q ¹ represents a divalent linking group. represents, C ¹ represents an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an acyl group or an acyloxy group, j is 0 or 1, represents p, q, r the number of each 0-5, n represents a number of 1 to 3, the sum of the numbers of B ¹ and B ^{2 is} a number of 3 to 10, and when p, q and r are each 2 or more, 2 or more of B ¹ , Q ¹ and B ² may be the same or different, and when n is 2 or more, two or more {(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r } may be the same or different. ) The liquid crystal composition according to claim 1, wherein the dichroic dye is a compound represented by the following general formula (2).

R ¹ is a substituent represented by -S-{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r } _n -C ¹ . Here, S is a sulfur atom, and B ¹ , B ² , Q ¹ , p, q, r, and n have the same definitions as those in the general formula (1) described in claim 2. R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each a hydrogen atom or a substituent. The liquid crystal composition according to claim 1, wherein the dichroic dye is a compound represented by the following general formula (3).

In the formula, each of R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ is a hydrogen atom or a substituent, and at least one of them is —S — {(B ¹ ) _p —. (Q ¹ ) _q — (B ² ) _r } _n is a substituent represented by C ¹ . Here, S is a sulfur atom, and B ¹ , B ² , Q ¹ , p, q, r, and n have the same definitions as those in the general formula (1) described in claim 2. The liquid crystal composition according to claim 1, wherein the charged particles are titanium oxide. It is a liquid crystal element which has a pair of electrode whose at least one is a transparent electrode, and a liquid crystal layer between this pair of electrodes, Comprising: This liquid crystal layer is a liquid crystal composition as described in any one of Claims 1-4. A liquid crystal element which is a layer to be contained. The liquid crystal layer includes a plurality of microcapsules containing a dichroic dye that develops red, a microcapsule that contains a dichroic dye that develops green, and a microcapsule that contains a dichroic dye that develops blue The liquid crystal element according to claim 5, wherein each of the liquid crystal elements is arranged in layers.

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