JP2016110148A - Liquid crystal element, liquid crystal composition, screen and display using liquid crystal element - Google Patents

Abstract

Liquid crystal composition excellent in solubility of polymerizable monomer in host liquid crystal, high transparency when power is turned off, high scattering property when power is turned on, liquid crystal element excellent in high-speed response and electric reliability, and the liquid crystal element It is an object to provide a screen and a display having At least one is a transparent substrate, and has a pair of substrates with electrodes arranged opposite to each other, and a liquid crystal adjustment including a composite including a chiral nematic liquid crystal phase and a polymer resin phase between the substrates. A liquid crystal element having an optical layer, wherein the polymer resin phase contains a structure represented by the following general formula (1), and the dielectric anisotropy of the chiral nematic liquid crystal phase is positive: Is used. [Selection figure] None

Description

  The present invention relates to a liquid crystal element, a liquid crystal composition, a screen and a display using the liquid crystal element. More specifically, the present invention relates to a liquid crystal element capable of switching between a light transmission state and a light scattering state without using a polarizing plate, and a screen and a display using the liquid crystal element.

In recent years, among liquid crystal elements, a transmission-scattering type liquid crystal element using a difference in refractive index between a polymer and a liquid crystal or a liquid crystal domain by combining a liquid crystal and a transparent polymer resin does not require a polarizing plate. It is attracting attention because of its high visible light utilization efficiency.
Transmission-scattering liquid crystal elements include polymer-stabilized liquid crystals (PSLC) and polymer-dispersed liquid crystals (PDLC).
) Is widely known. In the former, a trace amount of polymer of about 5% by weight is connected as a network network in a liquid crystal phase that is continuously spread. The latter has a structure in which liquid crystal phase droplets are dispersed in a polymer film (Non-Patent Document 1).

These liquid crystal elements are put into practical use as dimming shutters for the purpose of protecting design and privacy in windows, doors, partitions and the like of vehicles such as trains and cars, business buildings and hospitals. It is also used as a display device for displaying characters and figures.
In such a device, since the use time in the transparent state is generally overwhelmingly long, from the viewpoint of power saving, it is transparent when no voltage is applied, and operates in a reverse mode electro-optic effect that operates in a scattering state when a voltage is applied. It is desirable to have

  In order to realize this reverse mode transmission-scattering type liquid crystal element, generally, a liquid crystal composition to which a polymerizable monomer is added is photocured while maintaining a transparent state such as homogeneous, planar, homeotropic, etc. And a method of forming a polymer resin composite is known. As such liquid crystal elements, PSCT (Polymer Stabilized Cholesteric Texture) using visible light transmission scattering due to phase change of chiral nematic liquid crystal with positive dielectric anisotropy as PSLC and negative dielectric anisotropy as PDLC. A method of using liquid crystal is known. The latter has problems such as a large temperature dependency of light transmittance, a large viewing angle dependency, or an expensive liquid crystal. On the other hand, the former has the advantages that the temperature dependence of the light transmittance is small and the viewing angle dependence of the light transmittance is small, and that the response speed of the element is fast, and is promising.

  Patent Documents 1 to 3 disclose transmission-scattering liquid crystal elements that exhibit high transparency when the power is turned off, high scattering when the power is turned on, and high-speed response by applying a specific polymerizable monomer. . In general, in both PSLC and PDLC, when the liquid crystal composition is stored for a long period of time, or when composition separation such as precipitation of solids occurs when the liquid crystal element is produced, the appearance / uniformity of the liquid crystal element is impaired. Therefore, a polymerizable monomer having high solubility in the host liquid crystal is selected.

As a technique similar to PSLC, polymer alignment maintenance (PSA: Polymer Sustained Alignment) is known. In the PSA technique, a liquid crystal composition to which a very small amount of polymerizable monomer of 1% by weight or less is added is photocured in a liquid crystal element to form a polymer film on the alignment film surface, thereby stabilizing the liquid crystal alignment. It is known that a high-speed response and high electrical reliability of a liquid crystal element can be obtained by using this technique. Patent Document 4 discloses a liquid crystal element that exhibits a high-speed response by applying a specific polymerizable monomer. Patent Document 5 discloses a liquid crystal element that exhibits high host liquid crystal solubility, high-speed response, and high electrical reliability of a polymerizable monomer by applying a specific polymerizable monomer.

International Publication WO2012 / 133445 JP 2014-81630 A International Publication WO2014 / 051002 International Publication WO2004 / 033584 International Publication WO2011 / 092973

Dierking, I. Adv Mater 2000, 12, 167

The liquid crystal composition is required to have high solubility of the host liquid crystal of the polymerizable monomer. In addition, the transmission-scattering type liquid crystal element has high transparency when no DC voltage and / or AC voltage is applied (sometimes referred to as when the power is OFF), and when DC voltage and / or AC voltage is applied (when the power is ON). Characteristics) such as high scattering property, high-speed response, and high electrical reliability. Conventionally, a method for individually improving these characteristics has been shown, but a method for satisfying all of these properties in a balanced manner has not been shown.
When the transmission-scattering type liquid crystal element used in Patent Documents 1 to 3 is energized for a long time, the liquid crystal alignment is not restored even after the energization is stopped, and the transparency of the liquid crystal element is impaired. There was a problem of electrical reliability.

  Patent Document 4 and Patent Document 5 are optimized for the PSA technology, cannot be switched to the scattering mode, and require a member such as a polarizing plate to be used as a display, resulting in poor light utilization efficiency. There was a problem. When these are applied to transmission-scattering type liquid crystal elements, high solubility of the polymerizable monomer in the host liquid crystal, high transparency of the liquid crystal elements when the power is turned off, high scattering properties when the power is turned on, high-speed response and high electrical reliability Any of these or both were insufficient.

  The present invention has been made in view of the above problems, and an object thereof is to provide a liquid crystal composition excellent in solubility of a polymerizable monomer in a host liquid crystal. Another object of the present invention is to provide a liquid crystal element that is excellent in electrical reliability, and at the same time has high transparency when the power is turned off, high scattering when the power is turned on, and excellent high-speed response. It is another object of the present invention to provide a screen and a display having the liquid crystal element.

As a result of intensive studies to solve the above problems, the present inventors have used a liquid crystal composition using a specific liquid crystal and a polymerizable monomer, and a liquid crystal element containing a specific polymer resin in the liquid crystal light control layer. As a result, the present invention was reached. That is, the gist of the present invention is as follows.
[1] Liquid crystal dimming comprising at least one transparent substrate, having a pair of substrates with electrodes arranged opposite to each other, and comprising a composite including a chiral nematic liquid crystal phase and a polymer resin phase between the substrates A liquid crystal element having a layer, wherein the polymer resin phase contains a structure represented by the following general formula (1), and the dielectric anisotropy of the chiral nematic liquid crystal phase is positive.

[In general formula (1),
R ¹ and R ² each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent,
X ¹ and X ³ each independently represent a divalent group which may have a substituent,
X ² represents a divalent group which may have a direct bond or a substituent,
A ¹ and A ² each independently have a divalent aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a substituent. An optionally substituted cyclic aliphatic hydrocarbon group, wherein at least one of A ¹ and A ² is a group containing a cyclic aliphatic hydrocarbon group;
m ¹ and m ³ each independently represent an integer of 0 or more and 6 or less,
m ² represents an integer of 0 or more and 4 or less. ]
[2] The distance d between the pair of substrates with electrodes arranged opposite to each other is 2 μm or more, 1
00 μm or less, and the relationship between the chiral pitch length p and d of the chiral nematic liquid crystal is
The liquid crystal element according to [1], wherein d / p ≧ 1.
[3] The liquid crystal element according to [1] or [2], wherein the liquid crystal light control layer is a polymer-stabilized liquid crystal.
[4] The liquid crystal element according to any one of [1] to [3], which is a transmission-scattering element.
[5] The liquid crystal element according to any one of [1] to [4], wherein the liquid crystal element does not use a polarizing plate.
[6] The liquid crystal element according to any one of [1] to [5], wherein there is a region where the visible light transmittance when a DC voltage and / or an AC voltage is applied is lower than the visible light transmittance when no voltage is applied. The liquid crystal element according to any one of the above.
[7] The liquid crystal element according to any one of [1] to [6], wherein a haze when a DC voltage and / or an AC voltage is applied is 70% or more, and a haze when no voltage is applied is 15% or less. .
[8] In a temperature range of −10 ° C. or higher, the visible light transmittance of the liquid crystal element when no DC voltage and / or AC voltage is applied is 100%, and the visible light transmittance when a DC voltage and / or AC voltage is applied. Is normalized to 0%, the time from when the DC voltage and / or AC voltage is applied until the visible light transmittance reaches 10%, and when the DC voltage and / or AC voltage is not applied is visible. The liquid crystal element according to any one of [1] to [7], wherein the time until the light transmittance reaches 90% is 8 ms or less.
[9] A screen using the liquid crystal element according to any one of [1] to [8].
[10] A display using the liquid crystal element according to any one of [1] to [8].
[11] A liquid crystal comprising 0.5% by mass or more and 10% by mass or less of a chiral nematic liquid crystal having a positive dielectric anisotropy and a polymerizable monomer represented by the following general formula (3): Composition.

[In general formula (3),
R ³ and R ⁴ each independently represents an unsaturated acyl group,
X ⁴ and X ⁶ each independently represent a divalent group that may have a substituent,
X ⁵ represents a divalent group which may have a direct bond or a substituent,
A ³ and A ⁴ each independently have a divalent aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a substituent. An optionally substituted cyclic aliphatic hydrocarbon group, wherein at least one of A ³ and A ⁴ is a group containing a cyclic aliphatic hydrocarbon group;
n ¹ and n ³ each independently represents an integer of 0 or more and 6 or less,
n ² is 0 or an integer of 4 or less. ]
[12] The liquid crystal composition according to [11], wherein a chiral pitch length p of the chiral nematic liquid crystal is 0.3 μm or more and 3 μm or less.
[13] The liquid crystal-isotropic phase transition temperature of the liquid crystal composition is 40 ° C. or higher, [11] or [12]
The liquid crystal composition described in 1.
[14] A liquid crystal element formed using the liquid crystal composition according to any one of [11] to [13].

Since the liquid crystal composition of the present invention has high solubility of the polymerizable monomer contained therein, it has excellent storage stability of the liquid crystal composition, and precipitation of a solid content such as a polymerizable monomer during production of a liquid crystal element is suppressed, and high productivity. Is obtained.
In the liquid crystal element of the present invention, at least one of the substrates is a transparent substrate, and a pair of substrates with electrodes arranged opposite to each other, and a liquid crystal light control layer composed of a composite of a liquid crystal phase and a polymer resin phase between the substrates are provided. Hold it. Since the polymer resin phase has a specific structure, the liquid crystal element is excellent in electrical reliability, and at the same time, has high transparency when the power is turned off, high scattering properties when the power is turned on, and high-speed response. The liquid crystal element of the present invention is useful for use in screens, displays and the like because of the above characteristics. For example, it can be used as a visual field blocking element in a building window, a partition, or the like. It can also be used as a display for notice boards, show windows, computer terminals, projections, and the like.

The description of the constituent requirements described below is an example (representative example) of an embodiment of the present invention, and is not specified by these contents.
[Liquid crystal element]
The liquid crystal element of the present invention can be switched between a light transmission state and a light scattering state (transmission-scattering type). The switching between the light transmission state and the light scattering state is performed by at least one of the liquid crystal elements being a transparent substrate, having a pair of substrates with electrodes arranged facing each other, and a liquid crystal phase and a polymer between the substrates. This can be realized by electrically driving a liquid crystal light control layer including a composite including a resin phase. As the liquid crystal light control layer, a composite of a transmission-scattering liquid crystal phase and a polymer resin phase that can be switched between a light transmission state and a light scattering state by electric drive can be used.

  In general, it is known that a mixture in which a plurality of liquid crystalline substances are mixed absorbs ultraviolet light to cause some molecules to undergo a photoreaction and generate ionic impurities. Also, in the polymerizable compound, not all molecules contribute to the polymerization reaction when absorbing ultraviolet light, and some molecules generate ionic impurities as a side reaction. Therefore, an exposure process in which a liquid crystal composition containing a liquid crystal and a polymerizable compound is sandwiched between two electrode substrates and the polymerizable compound is polymerized by exposure to ultraviolet light generates the ionic impurities, and the liquid crystal element has an electrical property. It causes a decrease in reliability.

In the liquid crystal element of the present invention, since the liquid crystal composition has a polymerizable compound having a specific structure, ionic impurities generated in the liquid crystal phase by the ultraviolet light exposure process can be reduced, and the liquid crystal element has an electrical property. It has been found that reliability can be improved.
The reason why the liquid crystal element of the present invention can reduce ionic impurities generated in the liquid crystal phase and is excellent in the electrical reliability of the liquid crystal element is that the active radicals generated by the mixture of the liquid crystal and the polymerizable compound absorbing ultraviolet light are generated, This is presumably because the polymerizable compound having a specific structure is efficiently trapped and converted into a polymerization reaction efficiently. In addition, by incorporating a cyclic structure of an aliphatic hydrocarbon group at a position where the π-electron conjugation is reduced or broken in the molecular structure of the polymerizable compound, the ultraviolet absorption of the polymerizable compound is suppressed, and ionic impurities, etc. It is estimated that the generation of decomposition products was reduced.

  The ionic impurities in the liquid crystal phase cause a “burn-in” phenomenon that causes threshold abnormality due to repeated power ON / OFF switching to the liquid crystal element and continuous driving for a long time. When image sticking occurs in the transmission-scattering type liquid crystal element, haze at the time of turning off the power is increased, and transparency is deteriorated. Since the liquid crystal element of the present invention can reduce ionic impurities generated in the liquid crystal phase, it can suppress burn-in and increase transparency when the power is turned off.

Further, the liquid crystal element of the present invention can reduce ionic impurities in the liquid crystal phase, which is advantageous for electric driving of the liquid crystal element, and is excellent in high scattering property and high-speed response when the liquid crystal element is turned on.
In addition, since the liquid crystal element of the present invention performs optical modulation by switching light scattering, display can be performed without using a polarizing plate. Therefore, the liquid crystal element of the present invention can have a transmittance exceeding 50% and has high light utilization efficiency.

  The liquid crystal element of the present invention is a liquid crystal light control layer comprising at least one transparent substrate, a pair of substrates with electrodes arranged opposite to each other, and a composite containing a chiral nematic liquid crystal phase and a polymer resin phase between the substrates Is sandwiched between them. The polymer resin phase is not particularly limited as long as it contains the structure represented by the general formula (1) in the polymer and the dielectric anisotropy of the chiral nematic liquid crystal phase is positive. The configuration will be described.

<Board>
Examples of the material of the substrate include colorless transparent or colored transparent or opaque materials such as inorganic transparent materials such as glass and quartz, metals, metal oxides, semiconductors, ceramics, plastic plates, and plastic films. On the substrate, for example, a thin film of metal oxide, metal, semiconductor, organic conductive material or the like is formed on the entire surface of the substrate or partially by a known coating method, printing method, vapor deposition method such as sputtering, or the like. is there. Alternatively, it may be partially etched after forming a conductive thin film. In particular, in order to obtain a large-area liquid crystal device, from the viewpoint of productivity and workability, an ITO (mixture of indium oxide and tin oxide) electrode on a transparent polymer film such as PET is deposited by sputtering or printing. It is desirable to use an electrode substrate formed using A wiring for connecting the electrodes or connecting the electrodes and the outside may be provided on the substrate. For example, a segment driving electrode substrate, a matrix driving electrode substrate, an active matrix driving electrode substrate, or the like may be used.

Furthermore, the electrode surface provided on the substrate is a protective film or alignment film made of an organic compound such as polyimide, polyamide, silicon, and cyanide, an inorganic compound such as SiO ₂ , TiO ₂ , and ZrO ₂ , or a mixture thereof. The entire surface or a part thereof may be covered. The substrate may be aligned so that the liquid crystal is aligned with respect to the surface of the substrate. When the alignment is processed, any alignment processing can be used as long as the liquid crystal composition in contact has a planar structure. It doesn't matter. For example, the two substrates may be in a homogeneous orientation, or may be a so-called hybrid in which one is homogeneous orientation and the other is homeotropic orientation. For these alignment treatments, the electrode surface may be directly rubbed, or a normal alignment film such as polyimide used for TN liquid crystal, STN liquid crystal or the like may be used.

  In addition, as a method for producing the alignment film, a so-called photo-alignment method may be used in which the organic thin film on the substrate is irradiated with light having anisotropy such as linearly polarized light to give the film anisotropy. Note that, when the liquid crystal element is manufactured, the alignment treatment of the substrate is not necessarily required if the alignment of the unpolymerized liquid crystal composition can be controlled with respect to the substrate surface. That is, before the liquid crystal composition of the present invention is photopolymerized, the liquid crystal composition can be aligned to take a planar structure by a method such as flowing the liquid crystal composition or applying a shear stress.

  The opposing substrate may have an adhesive layer including a resin body that adheres and supports the substrate as appropriate at the peripheral part. In addition, the end face of the liquid crystal element or the injection port of the liquid crystal composition in the present invention is a tape such as an adhesive tape, a thermocompression bonding tape, a thermosetting tape, and / or a thermosetting resin, a photocurable resin, or a moisture curing. Resin, room temperature curable adhesive, anaerobic adhesive, epoxy adhesive, silicone adhesive, fluororesin adhesive, polyester adhesive, vinyl chloride adhesive, etc. By sealing with a plastic resin or the like, it is possible to prevent exudation of the internal liquid crystal and the like. In addition, this sealing may work to prevent deterioration of the liquid crystal element at the same time. In this case, the end face may be protected by covering the entire end face, or by pouring a curable resin or thermoplastic resin from the end face into the liquid crystal element and solidifying it. It may be covered with tapes.

  Spacers such as spherical or cylindrical glass, plastic, ceramic, or plastic film may be present between the substrates arranged to face each other. The spacer may be present as a component of the liquid crystal composition of the present invention so that it may be present in the liquid crystal light control layer between the substrates. The spacer is dispersed on the substrate during the assembly of the liquid crystal element or mixed with an adhesive. Or may be present in the adhesive layer.

<Liquid crystal light control layer>
The liquid crystal light control layer included in the liquid crystal element of the present invention includes a composite including a chiral nematic liquid crystal phase and a polymer resin phase. The liquid crystal light control layer used in the present invention can be switched between a light transmission state and a light scattering state by a DC voltage, an AC voltage, a pulse voltage, or a combination thereof having an effective value equal to or greater than a threshold value. The liquid crystal light control layer may be driven in a reverse mode in which a light transmission state is applied when no voltage is applied and the light application state is a light scattering state, or a light transmission state is applied when the voltage is not applied. It may be one that drives in the normal mode. Alternatively, a memory mode drive in which voltage is applied only when switching between the light transmission state and the light scattering state may be used.

  A method for producing a reverse mode liquid crystal element using the liquid crystal composition of the present invention is disclosed in, for example, JP-T-06-507505. A method for producing a normal mode liquid crystal device using the liquid crystal composition of the present invention is disclosed in, for example, JP-A-06-507505 and JP-A-07-043690. A method for producing a memory mode liquid crystal element using the liquid crystal composition of the present invention is disclosed in, for example, JP-T-7-507083.

  Next, the case where PSCT is used as the liquid crystal light control layer and used in the reverse mode will be described. When no voltage is applied to the liquid crystal element, almost all of the liquid crystal helical axes are in a planar phase that is perpendicular to the substrate, and a light transmission state is obtained. By applying a voltage between the electrode substrates of the liquid crystal light control layer, the liquid crystal helical axis having a positive dielectric anisotropy is phase-shifted into a focal conic phase facing a random direction, and enters a light scattering state. By switching between these two phases, the haze of the liquid crystal element can be controlled.

On the other hand, the case where PDLC is used as the liquid crystal light control layer and used in the normal mode will be described. When no voltage is applied to the liquid crystal element, the liquid crystal helical axis of the liquid crystal phase dispersed in the polymer resin phase becomes a focal conic phase in a random direction due to strong binding by the polymer resin phase, resulting in a light scattering state. . On the other hand, when a voltage is applied between the electrode substrates of the liquid crystal light control layer, the major axis of the liquid crystal molecule having negative dielectric anisotropy becomes a homeotropic phase that faces in a direction perpendicular to the substrate, and enters a light transmission state. .

As long as the liquid crystal light control layer of the present invention includes a chiral nematic liquid crystal phase and a polymer resin phase having a specific molecular structure, there is no limitation on the element system such as PSLC and PDLC. Electrical reliability, high transparency when the power is turned off, high scattering when the power is turned on, high-speed response, and the like can be obtained.
The liquid crystal light control layer of the present invention is more preferably PSLC. The characteristics of PSLC are that the polymer resin phase has a network polymer network structure, and the ratio of the polymer resin phase to the liquid crystal phase is 10% by mass or less, and the liquid crystal phase is in the liquid crystal light control layer. It is mentioned that it is the structure connected continuously. PSLC has the advantage that the elastic interaction at the interface between the liquid crystal phase and the polymer resin phase is large, and the response speed of falling of the liquid crystal element is faster than other systems. In addition, transparency when no voltage is applied to the liquid crystal element and scattering intensity when a voltage is applied can be sufficiently increased.

  The ratio of the liquid crystal phase and the polymer resin phase in the liquid crystal light control layer is not particularly limited as long as the effects of the present invention are not impaired. The polymer resin phase is preferably 10% by mass or less, and more preferably 7% by mass or less, with respect to the liquid crystal phase. Moreover, it is preferable that it is 0.1 mass% or more, and it is still more preferable that it is 1 mass% or more. When the ratio of the polymer resin phase is 0.1% by mass or more, the polymer resin phase becomes mechanically tough and tends to be excellent in repeated durability of the liquid crystal element. In addition, since liquid crystal molecules can receive sufficient interface interaction, the contrast and response speed of transmission scattering of the liquid crystal element may be improved. On the other hand, when the ratio of the polymer resin phase is 10% by mass or less, an increase in driving voltage is suppressed, and the transparency of the liquid crystal element tends to increase.

The liquid crystal light control layer of the present invention may contain other components in addition to the liquid crystal phase and the polymer resin phase. For example, a pigment may be included. Specifically, it can be used in a state where a dichroic dye is added and dissolved in the liquid crystal.
When a dye is added to the liquid crystal, the intrinsic absorption wavelength based on the molecular orientation of the dye, that is, the absorption, transmission, and scattering characteristics of light of a specific wavelength according to the dichroic ratio are electrically controlled according to the movement of the liquid crystal molecules. It can be used as a dimming / optical element member that can be controlled to a high degree. Specifically, by having a pigment, it is possible to strongly absorb only a component of a specific wavelength or to enhance scattering, thereby complementing wavelength anisotropy. This makes it possible to design a desired color rendering effect according to the application destination of the element.

<Polymer resin phase>
The polymer resin phase of the present invention contains a structure represented by the following general formula (1).

[In general formula (1),
R ¹ and R ² each independently represent a hydrogen atom or a substituent having 1 or more carbon atoms,
Represents 6 or less alkyl groups,
X ¹ and X ³ each independently represent a divalent group that may have a substituent, X ² represents a divalent group that may have a direct bond or a substituent,
A ¹ and A ² each independently have a divalent aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a substituent. An optionally substituted cyclic aliphatic hydrocarbon group, wherein at least one of A ¹ and A ² is a group containing a cyclic aliphatic hydrocarbon group;
m ¹ and m ³ each independently represent an integer of 0 or more and 6 or less,
m ² represents an integer of 0 or more and 4 or less. ]

(X ¹ , X ² and X ³ )
X ¹ and X ³ each independently represent a divalent group that may have a substituent, and X ² represents a divalent group that may have a direct bond or a substituent.
The divalent group for X ² is not particularly limited, and examples thereof include an ether bond, an ester bond, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and an aromatic heterocyclic group. Among these, an aliphatic hydrocarbon group or an ether bond is preferable from the viewpoint of high solubility in liquid crystals.
In addition, the divalent group of X ¹ and X ³ is not particularly limited, and examples thereof include an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and an aromatic heterocyclic group. Among these, an aliphatic hydrocarbon group is preferable from the viewpoint of high solubility in liquid crystals.

The combination of X ¹ , X ² and X ³ is not particularly limited, and may be the same or partly or entirely different, but is preferably the same from the viewpoint of the ease of the production method.
Examples of the substituent which may have include an alkyl group, an alkoxy group, and an alkyl carboxyl group. Among these, an alkyl group and an alkoxy group are preferable from the viewpoint of solubility in liquid crystals.

(Divalent aliphatic hydrocarbon group)
Examples of the aliphatic hydrocarbon group include divalent aliphatic hydrocarbon groups that are linear, branched and cyclic. For example, methylene group, ethylene group, propylene group, 1,2-cyclobutanediyl group, 1,3-cyclobutanediyl group, 1,2-cyclopentanediyl group, 1,3-cyclopentanediyl group, 1,4-cyclo Pentanediyl group, 1,1-cyclohexanediyl group,
1,2-cyclohexanediyl group, 1,3-cyclohexanediyl group, 1,4-cyclohexanediyl group, 1,1-cycloheptanediyl group, 1,2-cycloheptanediyl group, 1,3-cycloheptanediyl group 1,4-cycloheptanediyl group, etc., preferably methylene group, ethylene group, propylene group, 1,3-cyclobutanediyl group, 1,3-cyclopentanediyl group, 1,4-cyclopentanediyl group 1,4-cyclohexanediyl group, 1,3-cyclohexanediyl group, 1,3-cycloheptanediyl group, 1,4-cycloheptanediyl group.
The number of carbon atoms is preferably 4 or more, more preferably 5 or more, more preferably 8 or less, and even more preferably 7 or less. It exists in the tendency which does not inhibit the alignment with a liquid crystal by being in these ranges.

(Divalent aromatic hydrocarbon group)
The aromatic hydrocarbon group is not particularly limited as long as it does not impair the effects of the present invention. It is a divalent group obtained by removing two hydrogen atoms from a single ring or a condensed ring formed by condensing 2 to 4 thereof.

The aromatic hydrocarbon group preferably has 6 or more carbon atoms, while the carbon number is preferably 30 or less, more preferably 26 or less, and preferably 18 or less. By being in these ranges, the reactivity during polymerization tends to be improved.
Specific examples of the aromatic hydrocarbon group include a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluoranthene ring, fluorene ring, etc. The group of is mentioned. Among these, a benzene ring or a naphthalene ring is preferable from the viewpoint of improving the solubility in liquid crystal.

(Divalent aromatic heterocyclic group)
The aromatic heterocyclic group is not particularly limited as long as it does not impair the effects of the present invention. It is a divalent group obtained by removing two hydrogen atoms from a single ring or a condensed ring formed by condensing 2 to 4 thereof.
The aromatic heterocyclic group preferably has 6 or more carbon atoms. On the other hand, the number of carbon atoms is preferably 30 or less, more preferably 26 or less, and particularly preferably 18 or less. By being in these ranges, the reactivity during polymerization tends to be improved.

  Specific examples of the aromatic heterocyclic group include furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole. Ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring , Quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring and the like. Among these, a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring or an oxadiazole ring is preferable from the viewpoint of solubility in liquid crystals.

^{(A 1} and ^A 2)
A ¹ and A ² each independently have a divalent aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a substituent. A cyclic aliphatic hydrocarbon group which may be substituted.
In addition, at least one of A ¹ and A ² includes a cyclic aliphatic hydrocarbon group. Since at least one of A ¹ and A ² contains a cyclic aliphatic hydrocarbon group, the ultraviolet absorption of the polymerizable compound is suppressed, the generation of decomposition products is reduced, and the electrical reliability of the liquid crystal element is improved. To do. Note that including a cyclic aliphatic hydrocarbon group may be an aliphatic hydrocarbon group itself, or an aliphatic hydrocarbon group and another group may be linked by a single bond. A structure in which a group hydrocarbon group and another ring structure are condensed may be used.

At least one of A ¹ and A ² may contain a cyclic aliphatic hydrocarbon group, and both may have them. From the viewpoint of ease of production, it is preferable that one of A ¹ and A ² has.
Examples of the aromatic hydrocarbon group which may have a substituent and the aromatic heterocyclic group which may have a substituent include those represented by X ¹ , X ² and X ³ .

(Divalent cyclic aliphatic hydrocarbon group)
The cyclic aliphatic hydrocarbon group is not particularly limited as long as it does not impair the effects of the present invention. For example, 1,2-cyclobutanediyl group, 1,3-cyclobutanediyl group, 1,2
-Cyclopentanediyl group, 1,3-cyclopentanediyl group, 1,4-cyclopentanediyl group, 1,1-cyclohexanediyl group, 1,2-cyclohexanediyl group, 1,3-
And cyclohexanediyl group, 1,4-cyclohexanediyl group, 1,1-cycloheptanediyl group, 1,2-cycloheptanediyl group, 1,3-cycloheptanediyl group, 1,4-cycloheptanediyl group, and the like. Preferably methylene group, ethylene group, propylene group, 1,3-cyclobutanediyl group, 1,3-cyclopentanediyl group, 1,4-cyclopentanediyl group, 1,4-cyclohexanediyl group, 1,3 A cyclohexanediyl group,
1,3-cycloheptanediyl group and 1,4-cycloheptanediyl group.

(A divalent group in which an aliphatic hydrocarbon group and another group are linked by a single bond)
The group in which the aliphatic hydrocarbon group and another group are linked by a single bond is not particularly limited as long as the effect of the present invention is not impaired, and examples thereof include the following groups.

  Among the above, the following groups are preferable.

(A divalent aliphatic hydrocarbon group and a group condensed with another ring structure)
The group in which the aliphatic hydrocarbon group and other ring structure are condensed is not particularly limited as long as it does not impair the effects of the present invention, and includes the following groups.

  Among the above, the following groups are preferable.

The number of carbon atoms is preferably 4 or more, more preferably 5 or more, more preferably 8 or less, and even more preferably 7 or less. By being in these ranges, the reactivity at the time of polymerization at the time of liquid crystal element formation is improved, and the electrical reliability of the liquid crystal element tends to be improved.
A ¹ and A ² may have a substituent. For example, an alkyl group, an alkoxy group, an alkyl carboxyl group, etc. are mentioned. Among these, an alkyl group or an alkoxy group is preferable from the viewpoint of solubility in liquid crystals.

(R ³ and R ⁴ )
R ³ and R ⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent. The alkyl group having 1 to 6 carbon atoms may be linear or branched. Among these, from the viewpoint of improving the reactivity during polymerization, a hydrogen atom or an alkyl group having 1 to 4 carbon atoms is preferable, and a hydrogen atom or an alkyl group having 1 or 2 carbon atoms is more preferable.

The substituent that the alkyl group having 1 to 6 carbon atoms may have is not particularly limited, and examples thereof include an ether bond, an ester bond, a halogen atom, and a cyano group. Among these, an ether bond, a halogen atom, or a cyano group is preferable from the viewpoint of solubility in liquid crystals.

(M ¹ and m ³ )
m ¹ and m ³ each independently represents an integer of 0 or more and 6 or less. Among these, 0, 1 or 2 is preferable from the viewpoint of improving the solubility in liquid crystal.

(M ² )
m ² represents an integer of 0 or more and 4 or less. Among these, 0, 1 or 2 is preferable from the viewpoint of improving the solubility in liquid crystal.
Among the general formula (1), a structure represented by the following general formula (2) is particularly preferable because reactivity during polymerization tends to be improved.

^{R 1, R 2, X 2} , A 1, A 2 and ^{m 2} in general formula (2) is, ^R 1 in the formula ^{(1), R 2, X 2, A} 1, A 2 and ^{m 2} And the substituents and preferred ranges that may be present are also synonymous.
Although the specific example of the structure represented by General formula (1) is given below, this invention is not limited to these, unless the summary is exceeded.

<Other ingredients>
The polymer resin phase of the present invention includes a polymer resin obtained by polymerizing a polymerizable monomer described later. In addition to the structure represented by the general formula (1), other components and structures may be included as long as the effects of the present invention are not impaired.
The ratio between the structure represented by the general formula (1) and the other structure of the liquid crystal element of the present invention is not particularly limited as long as the effect of the present invention is not impaired, but is represented by the general formula (1). The structure is preferably 30% by mass or more, more preferably 50% by mass or more, and most preferably 80% by mass or more.

When the ratio of the structure represented by the above formula (1) is in an appropriate range, liquid crystal element production in a short time, high contrast, short response time and the like tend to be sufficiently obtained. Moreover, the upper limit of the structure represented by the above formula (1) is 100% by mass.
Specific examples of other structures include the following.

  Moreover, when the polymer resin which the polymer resin phase of this invention has is a copolymer, any of an alternating copolymer, a block copolymer, a random copolymer, and a graft copolymer may be sufficient.

<Chiral nematic liquid crystal phase>
The liquid crystal used for the chiral nematic liquid crystal phase of the present invention is not particularly limited as long as the dielectric anisotropy of the chiral nematic liquid crystal phase is positive, and can be selected according to the desired characteristics of the liquid crystal element.

<Chiral Nematic Liquid Crystal>
The chiral nematic liquid crystal used in the liquid crystal phase of the present invention and the liquid crystal composition described below is not particularly limited, but has a positive dielectric anisotropy. Further, since the dielectric anisotropy of the chiral nematic liquid crystal of the present invention is positive, it can be used as a transmission-scattering type element in the reverse mode, normal mode, and memory mode.

The dielectric anisotropy value (Δε) of the chiral nematic liquid crystal is not particularly limited as long as it is positive.
The number is preferably 5 or more, and more preferably 8 or more for reducing the driving voltage of the liquid crystal element. Moreover, when using a polymerization initiator, it is preferable from the point which shortens the polymerization time of a polymerizable monomer that each molecule | numerator which comprises a chiral nematic liquid crystal does not have absorption of the wavelength which overlaps with the absorption wavelength of an initiator.

  As the chiral nematic liquid crystal, the liquid crystal itself may be an assembly of liquid crystalline compounds exhibiting a cholesteric phase, or a chiral nematic liquid crystal may be formed by adding a chiral agent to the nematic liquid crystal. From the viewpoint of designing the liquid crystal composition, it is preferable to add a chiral agent to the nematic liquid crystal according to the purpose and control the chiral pitch length (p) and the liquid crystal-isotropic phase transition temperature (Tni).

As an example, a case of using as a reverse mode PSCT element will be described.
In order to shorten the rising response time τ ₁ , it is advantageous to apply as high a voltage as possible between the electrode substrates of the liquid crystal light control layer. However, if the applied voltage is too high, there is a dilemma that the phase transitions to the homeotropic phase and sufficient light scattering cannot be obtained. In order to solve this problem, it is preferable that the relationship d / p between the chiral pitch length p of the chiral nematic liquid crystal and the distance d between the pair of substrates with electrodes arranged opposite to each other is 1 or more. More preferably, it is 2 or more, particularly preferably 4 or more. Moreover, it is preferable that it is 20 or less, and it is especially preferable that it is 12 or less.

As d / p increases, scattering during driving increases, and the light shielding characteristics are improved. Further, as d / p is increased, the threshold voltage from the focal conic phase to the homeotropic phase is increased, and even when a high voltage is applied, the light transmission state is not changed and the light scattering state can be maintained. Therefore, the rising response time τ ₁ can be shortened. On the other hand, since the driving voltage (threshold voltage from the planar phase to the focal conic phase) of the liquid crystal element also increases at the same time, it is preferable that the driving voltage is within the above range from the viewpoint of achieving both light shielding characteristics and energy saving and safety.

The p of the chiral nematic liquid crystal is preferably 0.3 μm or more, and more preferably 0.8 μm or more. On the other hand, it is preferably 3 μm or less, more preferably 2 μm or less.
If p is not too small, the driving voltage of the liquid crystal element tends to be kept low, and if it is not too large, the contrast tends to be high.
In general, since p is inversely proportional to the concentration of the chiral agent, the concentration of the chiral agent may be determined by calculating backward from the necessary value of p. When p × n (n is the refractive index of chiral nematic liquid crystal) is in the visible light wavelength range (380 nm to 800 nm), the finally obtained liquid crystal element is colored when no voltage is applied, and is out of the visible light range. In this case, since it becomes colorless and transparent when no voltage is applied, p may be selected according to the purpose.
The distance d between the pair of substrates with electrodes arranged opposite to each other in the liquid crystal element of the present invention needs to be not less than p of the chiral nematic liquid crystal to be used, preferably 2 μm or more, more preferably 3 μm or more, 5 μm or more is particularly preferable. Moreover, 100 micrometers or less are preferable and 20 micrometers or less are still more preferable.

The light transmittance of the liquid crystal element in a state where no voltage is applied decreases with an increase in d, and the response time of the display element may become longer. On the other hand, if d is too small, the light shielding characteristics during driving are reduced, and in the case of a large-area liquid crystal element, the liquid crystal element may be short-circuited. By being in the above range, these requirements can be satisfied in a balanced manner.
Tni of the chiral nematic liquid crystal is preferably 50 ° C. or higher and more preferably 70 ° C. or higher because the upper limit temperature at which the liquid crystal element can operate is determined by Tni of the chiral nematic liquid crystal. On the other hand, as Tni increases, the viscosity tends to increase, so that it is preferably 200 ° C. or lower, and more preferably 150 ° C. or lower.

  The nematic liquid crystal may be any known one, and the molecular skeleton, substituent, and molecular weight of the constituent molecules are not particularly limited, and may be a synthetic product or a commercial product. It is preferable that the dielectric anisotropy of the nematic liquid crystal is positive and large in order to make the dielectric anisotropy of the chiral nematic liquid crystal phase of the liquid crystal element and the chiral nematic liquid crystal of the liquid crystal composition positive. In addition, when a polymerization initiator is used, it is preferable from the viewpoint of shortening the polymerization time of the polymerizable monomer that each molecule constituting the constituent molecule does not have absorption at a wavelength that overlaps the absorption wavelength of the initiator. In addition, various additives may be included as long as the optical and electrical characteristics of the dichroic dye and the liquid crystal element are not disturbed.

  When using a known liquid crystalline substance, specifically, the Japan Society for the Promotion of Science 142nd edition; “Liquid Crystal Device Handbook”, Nihon Kogyo Shimbun (1989), pages 152 to 192 and the Liquid Crystal Handbook Editorial Committee Edition: “Liquid Crystal Handbook” Maruzen Co., Ltd. (2000), pages 260 to 330, biphenyl series, phenylcyclohexane series, cyclohexylcyclohexane series, alkyl halide series, tolan series, etc. Molecular compounds or mixtures can be used. In addition, a high molecular weight compound or a mixture described in “Liquid Crystal Handbook” Maruzen Co., Ltd. (2000), pages 365 to 415, edited by the Liquid Crystal Handbook Editorial Committee, can also be used. Examples of the compound constituting the nematic liquid crystal include the following compounds.

As the cholesteric liquid crystal and nematic liquid crystal, those having a low viscosity and a high dielectric anisotropy are preferable in terms of high-speed response and manufacturability of the liquid crystal element.
The chiral agent may be any chiral compound that is compatible with the host liquid crystal, may be a synthetic product or a commercial product, may exhibit liquid crystal properties, or may have a polymerizable functional group. good. Further, dextrorotatory or levorotatory may be used, and a dextrorotatory chiral agent and a levorotatory chiral agent may be used in combination. Moreover, as a chiral agent, its own dielectric anisotropy is positively large,
A material having a low viscosity is preferable from the viewpoint of a reduction in driving voltage and response speed of the liquid crystal element, and a larger helical twisting power, which is an index of the force with which the chiral agent twists the liquid crystal, is preferable. When a polymerization initiator is used, it is preferable that the polymerization initiator does not have absorption at a wavelength that overlaps the absorption wavelength of the initiator.

Examples of the chiral agent include CB15 (trade name, manufactured by Merck), C15 (trade name, manufactured by Merck), S-811 (trade name, manufactured by Merck), R-811 (trade name, manufactured by Merck), S-1011 ( Trade name, manufactured by Merck), R-1011 (trade name, manufactured by Merck), and the like.
[Method of manufacturing liquid crystal element]
The liquid crystal light control layer of the liquid crystal element of the present invention is, for example, formed as a sealed cell by forming an adhesive layer with a photocurable adhesive or the like at a peripheral portion of a pair of substrates with electrodes arranged opposite to each other via a spacer. Two or more adhesive layer cutouts are immersed and injected into the liquid crystal composition of the present invention under normal pressure or vacuum, or a liquid crystal composition is applied onto one substrate using a coater, and After being sandwiched by a known method such as stacking the other substrate on the substrate, it is formed by polymerization and curing with radiation such as ultraviolet light, visible light, or electron beam. In the case of a plastic film substrate, a substrate with electrodes that is continuously supplied is sandwiched between two rubber rolls, and a mixture of a liquid crystal containing a spacer and dispersed therein and an uncured curable compound is interposed between the substrates, and then sandwiched. Productivity is high because it can be photocured continuously. In any of the methods, if the substrate is not subjected to alignment treatment, the liquid crystal composition is flowed before the uncured liquid crystal composition is photocured, or a liquid crystal composition is subjected to shear stress. It is necessary that the composition is oriented to assume a planar structure. Specifically, the liquid crystal composition can have a planar structure by injecting the liquid crystal composition of the present invention into a sealed cell that has not been subjected to alignment treatment.

  In the present invention, the method for polymerizing the liquid crystal composition is preferably photopolymerization. Among these, polymerization by ultraviolet rays is particularly preferable. The light source for photopolymerization may be any light source having a spectrum at the absorption wavelength of the radical photopolymerization initiator used, and typically any light source capable of irradiating light with a wavelength of 220 nm to 450 nm. . Examples include a high pressure mercury lamp, an ultra high pressure mercury lamp, a halogen lamp, a metal halide lamp, a UV-LED, a blue LED, a white LED, and the like. In addition, a heat ray cut filter, an ultraviolet ray cut filter, a visible light cut filter, or the like may be used in combination. Light may be applied to at least one surface from the transparent substrate of the liquid crystal element, and both surfaces may be irradiated when both surfaces of the substrate sandwiching the liquid crystal composition are transparent. Light irradiation may be performed at one time or may be performed by dividing into several times. So-called PSCOF (Phase Separated Composite Organic Film) (V. Vorflusevand S. Kumar, Science 283, in which the irradiance of light is distributed in the thickness direction of the liquid crystal element and the density of the polymer resin phase is continuously changed. 1903 (1999)).

In the case of photopolymerization, irradiance of light irradiated to the liquid crystal element is generally 0.01 mW / cm ² or more, preferably 1 mW / cm ² or more, more preferably 10 mW / cm ² or more, particularly preferably 30 mW / cm ² or more. If the irradiance is too small, the polymerization does not proceed sufficiently. In addition, for the photopolymerization of the liquid crystal composition, an integrated dose of ² J / cm ² or more, preferably ³ J / cm ² or more is usually given.

  The light irradiation time may be determined according to the radiation intensity of the light source. From the viewpoint of improving productivity, the light irradiation is usually completed within 200 seconds, preferably within 60 seconds. On the other hand, the light irradiation is performed for 10 seconds or more. It is preferable to do this. If the light irradiation time is too short, the repetition durability of the liquid crystal element may be inferior. When manufacturing a sheet-like liquid crystal device with a large area using a plastic film substrate, it is possible to use a method of irradiating light continuously while moving the light source or sheet, and adjusting the moving speed according to the irradiance of the light source do it.

In the liquid crystal light control layer obtained as described above, the chiral nematic liquid crystal is dispersed or formed into a continuous layer in a thin transparent polymer, but the continuous layer exhibits the best contrast. Is formed.
In the present invention, the temperature at which the liquid crystal composition is polymerized is preferably usually 0 ° C. or higher and 40 ° C. or lower. When the temperature is in an appropriate range, the polymerization reaction tends to proceed easily. Further, the heat accumulated with the polymerization reaction can suppress the temperature rise of the device, and the polymerization can be performed at a temperature lower than the phase transition temperature of the liquid crystal. Accordingly, the liquid crystal alignment is not locally disturbed, and the optical characteristics and driving durability of the liquid crystal element are hardly affected.

  The liquid crystal element of the present invention is colorless and excellent in transparency. This is because the structure represented by the general formula (1) contained in the polymer resin phase of the present invention has a fat at a position where the π-electron conjugation is reduced or divided as compared with a polymer resin used in a known liquid crystal element. It is presumed that the light absorption at the visible light wavelength is suppressed by incorporating the ring structure of the group. In addition, the polymerizable compound of the present invention tends to suppress the generation of impurities due to side reactions of the liquid crystal composition in the exposure process of the liquid crystal element, and is presumed to reduce the color-causing substances.

[Driving liquid crystal element]
The liquid crystal element of the present invention can be switched from a transparent state to a scattering state (opaque state) by applying a voltage or returning from a voltage application state to a voltage non-application state. Since the liquid crystal element of the present invention is a liquid crystal element that can be used in the reverse mode, there is a region where the visible light transmittance when a voltage is applied is lower than the visible light transmittance when no voltage is applied. Note that the voltage here refers to an AC and / or DC voltage.

  As one embodiment of the present invention, a screen using a liquid crystal element capable of switching between a light transmission state and a light scattering state is used as a transparent body, and an image projected by a projector or the like is formed when the screen is in a light scattering state. And see-through display that enables visual recognition. Specifically, when the screen is in a light scattering state or while the light transmission state is changed to the light scattering state, a projector or the like projects an image on a part or the whole of the liquid screen, and the screen element transmits light. In this state, the screen and the image projector are synchronized so that the image is not projected by the projector or the like.

By repeating this synchronization switching at a speed that cannot be followed by the human eye, when the image is projected onto the screen, the image appears to be raised. In these applications, the liquid crystal element is required to have high responsiveness, high contrast, and a specific haze value, and the liquid crystal element of the present invention can be suitably used.
In order to switch the liquid crystal element of the reverse mode of the present invention from the transparent state to the scattering state, a voltage sufficient to cause the chiral nematic liquid crystal phase to transition from the planar state to the focal conic state may be applied between the electrodes. The applied waveform is not particularly limited, such as direct current, alternating current, pulse, or a synthesized wave thereof. In the case of a DC voltage, preferably 0.5 msec or more, and in the case of an AC voltage, any of a sine wave, a rectangular wave, a triangular wave, or a composite wave thereof may be used, preferably a pulse wave of 0.5 msec or more at a frequency of 100 kHz or less. In this case, preferably, switching can be performed by applying a pulse width of 0.5 msec or more.

The driving voltage of the liquid crystal element is usually 60 V or less, preferably 30 V or less for a DC voltage, 120 Vp-p or less, preferably 90 Vp-p or less for an AC voltage, and a maximum value of 60 V or less for a pulse voltage. Preferably, the maximum value is 30V or less.
Further, the haze of the liquid crystal element of the present invention is that when no DC voltage and / or AC voltage is applied (the power is
15% or less at the time), and preferably 70% or more when the DC voltage and / or AC voltage is applied (when the power is turned on). In particular, it is particularly preferable that the power is 10% or less when the power is off and 90% or more when the power is on. Indoors and under fluorescent lamps, when haze exceeds 15%, cloudiness is conspicuous, and when it is less than 70%, there is a tendency that a silhouette beyond the liquid crystal element can be seen.

Further, the parallel light transmittance of the liquid crystal element of the present invention is preferably 75% or more when the power is turned off, 15% or less when the power is turned on, particularly preferably 80% or more when the power is turned off and 10% or less when the power is turned on. If it is less than 75% indoors or under a fluorescent lamp, it is dim, and if it exceeds 15%, an object in front tends to be seen.
In the present invention, the haze and parallel light transmittance of the liquid crystal element are measured according to JIS K7136 (2000).

<Response time of liquid crystal element>
The response time described in this specification means that the liquid crystal element has a visible light (380 to 800 nm) transmittance of 100% when no voltage is applied, and a visible light transmittance of 0% when the liquid crystal element is saturated by application of voltage. When normalized, when a test waveform (100 Hz rectangular wave in this embodiment) is applied, the time until the visible light transmittance reaches 10% (rise response time), when no test waveform is applied It is defined as the time until the visible light transmittance reaches 90% (falling response time). The method for measuring the response time is measured by the method described in the examples.

  The response time of the liquid crystal element of the present invention is preferably 8 msec or less, more preferably 5 msec or less, and more preferably 3 msec or less, at a temperature of −10 ° C. or higher. And particularly preferred. For use as a liquid crystal element, it is preferable that the rise response time is the same as the fall response time.

  The upper limit of the operating temperature of the liquid crystal element of the present invention is Tni of the chiral nematic liquid crystal phase. However, since the response time tends to be longer at low temperatures, the operating temperature range is preferably −10 ° C. or higher, more preferably 0 ° C. That's it. Moreover, it is preferably 60 ° C. or lower, and more preferably 40 ° C. or lower.

[Applications of liquid crystal elements]
The liquid crystal composition and the liquid crystal element of the present invention can be used for a liquid crystal element and a display. For example, it can be used as a display panel or projection panel such as a liquid crystal element for blocking the field of view such as building windows, partitions and show windows, or by electrically switching the display with high-speed response. Can do.

  The projection system includes front projection, rear projection and the like, and is not particularly limited. For example, a rear projection system disclosed in Japanese Patent Laid-Open No. 6-82748 or International Publication No. 2009/150579, or a projection using coherent light as disclosed in Japanese Patent Laid-Open No. 2010-217291 is used. Name the system.

[Liquid crystal composition]
The liquid crystal composition of the present invention contains 0.5 to 10% by mass of a chiral nematic liquid crystal having a positive dielectric anisotropy and a polymerizable monomer represented by the following general formula (3). It is.

[In general formula (3),
R ³ and R ⁴ each independently represents an unsaturated acyl group,
X ⁴ and X ⁶ each independently represent a divalent group that may have a substituent,
X ⁵ represents a divalent group which may have a direct bond or a substituent,
A ³ and A ⁴ each independently have a divalent aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a substituent. An optionally substituted cyclic aliphatic hydrocarbon group, wherein at least one of A ³ and A ⁴ is a group containing a cyclic aliphatic hydrocarbon group;
n ¹ and n ³ each independently represents an integer of 0 or more and 6 or less,
n ² is 0 or an integer of 4 or less. ]

  In general, composites of liquid crystal and polymer resin are designed to enhance the elastic interaction at the interface between the liquid crystal phase and the polymer resin phase in the liquid crystal light control layer by the π-π interaction between molecules. . For these, a polymerizable monomer having a molecular structure in which a π-electron system is distributed throughout the molecule was used. However, such a polymerizable monomer has a problem that the polymerizable monomers are stacked in a liquid crystal composition due to π-π interaction, and the solubility in the liquid crystal is lowered.

  In the liquid crystal composition of the present invention, the solubility in the liquid crystal is improved by using a polymerizable monomer having an aromatic hydrocarbon ring introduced at a position where the area of π-π stacking between the polymerizable monomers is reduced. . Surprisingly, even when a polymerizable monomer into which an aromatic hydrocarbon ring is introduced at a position that reduces the area of π-π stacking is used, high transparency when power is turned off, high scattering when power is turned on, and It has been found that a liquid crystal element excellent in high-speed response can be obtained.

  The polymerizable monomer represented by the general formula (3) is one of groups having a plurality of benzene rings such as a phenyl group or a naphthyl group, which a polymerizable monomer generally used as a liquid crystal composition has. The benzene ring is a cycloalkyl group such as a cyclohexyl group. As a result, by reducing the area of π-π stacking of polymerizable monomers, by suppressing aggregation of polymerizable monomers, it contributes to improving the solubility in liquid crystals, preserving the liquid crystal composition, There is no solid analysis at the time of processing a liquid crystal element, and high manufacturability is obtained.

(R ³ and R ⁴ )
R ³ and R ⁴ each independently represents an unsaturated acyl group. The number of types of unsaturated bonds that the unsaturated acyl group has is not particularly limited. Moreover, although carbon number is not specifically limited, 3 or more are preferable, 10 or less are preferable and 5 or less are still more preferable. By being in these ranges, the reactivity during polymerization tends to be improved.

Specific examples include acryloyl group, propioyl group, methacryloyl group, crotonoyl group, cinnamoyl group and the like.
Among these, an acryloyl group or a methacryloyl group is preferable from the viewpoint of improving the reactivity during polymerization.

(X ⁴ , X ⁵ and X ⁶ )
X ⁴ and X ⁶ each independently represent a divalent group that may have a substituent, and X ⁵ represents a divalent group that may have a direct bond or a substituent. Although it does not specifically limit as a bivalent group, The same thing as the bivalent group quoted by X < ¹ >, X < ² > and X < ³ > of said General formula (1) is mentioned.

Among these, an ether bond or an alkylene group is preferable from the viewpoint of improving the solubility in liquid crystal.
The substituent that X ⁴ , X ^5, and X ⁶ may have is the substituent that the divalent group of X ¹ , X ^2, and X ³ in the general formula (1) may have The same thing is mentioned, A preferable substituent is also synonymous.
The combination of X ⁴ , X ⁵ and X ⁶ is not particularly limited, and may be the same or partially or completely different, but is preferably the same from the viewpoint of the ease of the production method.

^{(A 3} and ^A 4)
A ³ and A ⁴ have the same meanings as A ¹ and A ^{2 in} the general formula (1), respectively, and the substituents, preferred ranges, and the like that may be included are also the same.

(N ¹ , n ² and n ³ )
n ^{1, n 2} and ^{n 3} have the general formula (1) ^m 1, and ^{m 2} and ^{m 3} of have the same meanings have optionally may substituents, preferred ranges etc. are also the same.
Among the polymerizable monomers represented by the general formula (3), the polymerizable monomer represented by the general formula (4) is preferable because the orientation regularity with the liquid crystal tends to be excellent.

[In general formula (4),
R ³ and R ⁴ each independently represents an unsaturated acyl group,
X ⁵ represents a divalent group which may have a direct bond or a substituent,
A ³ and A ⁴ each independently have a divalent aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a substituent. An at least one of A ¹ and A ² is a group containing a cyclic aliphatic hydrocarbon group;
n ² is 0 or represents 2 an integer. ]

Formula (4) in ^{R 3, R 4, X 5} , A 3, A 4 and ^{n 2, R} 3 in the general formula (3) ^{in, R 4, X 5, A} 3, A 4 and ^{n 2} And the substituents and preferred ranges that may be present are also synonymous.
Specific examples of the polymerizable monomer represented by the general formula (3) are shown below. This invention is not limited to these unless it exceeds the gist.

As the polymerizable monomer used in the liquid crystal composition of the present invention, only one type of polymerizable monomer represented by the general formula (3) may be used, or two or more types may be used in combination. Specifically, other polymerizable monomers having one or more ethylenically unsaturated double bonds, such as (meth) acrylic or vinyl, and one ethylenically unsaturated double bond It may be copolymerized with a polymerizable monomer represented by the above formula (3) by a polymerization reaction.

For example, polymerizable monomers such as monofunctional (meth) acrylic monomers, bifunctional (meth) acrylic monomers, trifunctional or higher polyfunctional (meth) acrylic monomers described in Japanese Patent Application Laid-Open No. 9-90328, (meth) Polymerizable oligomers such as acrylic oligomers can be used.
Examples of vinyl monomers include styrene, chlorostyrene, α-methylstyrene, divinylbenzene and the like.

  In the polymerizable monomer used for forming the polymer resin phase, the ratio of the polymerizable monomer having a plurality of polymerization reactive groups in one molecule is as described above, and the polymerizable monomer represented by the general formula (3) The ratio of the other polymerizable monomer is not particularly limited as long as it does not impair the effects of the present invention. Among these, the polymerizable monomer represented by the general formula (3) is preferably 30% by mass or more, more preferably 50% by mass or more, and most preferably 80% by mass or more.

When the ratio of the polymerizable monomer represented by the general formula (3) is within an appropriate range, a liquid crystal device can be produced in a short time, and has high responsiveness, high transparency, high scattering properties, and low coloration. In addition, a liquid crystal element excellent in durability and deterioration with time tends to be obtained. Moreover, the upper limit of the polymerizable monomer represented by the general formula (3) is 100% by mass.
Moreover, when the polymer resin which the polymer resin phase of this invention has is a copolymer, any of an alternating copolymer, a block copolymer, a random copolymer, and a graft copolymer may be sufficient.

<Chiral Nematic Liquid Crystal>
The chiral nematic liquid crystal contained in the liquid crystal composition of the present invention is synonymous with the chiral nematic liquid crystal described in the chiral nematic liquid crystal phase of the liquid crystal element, and specific examples, preferred ranges, and the like are also synonymous.

<Combination ratio>
The liquid crystal composition of the present invention is designed to exhibit a cholesteric phase at room temperature (25 ° C.), and the liquid crystal-isotropic phase transition temperature (Tni) is preferably 40 ° C. or higher, more preferably 60 ° C. or higher.
If Tni of the liquid crystal composition of the present invention is outside the above range, there is a concern that the liquid crystal structure may be destroyed due to a temperature rise derived from a light source or reaction heat during polymerization.

The ratio of the polymerizable monomer in the liquid crystal composition is 0.5% by mass or more and 10% by mass or less.
Preferably it is 7 mass% or less, Most preferably, it is 6.5 mass% or less. Moreover, it is preferably 0.1% by mass or more, particularly preferably 1% by mass or more.
When a plurality of polymerizable monomers and / or non-polymerizable monomers are used in combination, the total ratio of the polymerizable monomer and the non-polymerizable monomer to the liquid crystal composition is usually 0.2% by mass or more, preferably 1. On the other hand, it is usually 10% by mass or less, preferably 7% by mass or less. When this ratio is in an appropriate range, the repeated durability of the liquid crystal element tends not to decrease, and the haze at the time of transparency does not increase excessively, and the haze at the time of opaqueness may not decrease.

<Polymerization initiator>
When polymerizing the polymerizable monomer of the present invention, it is preferable to use a polymerization initiator. Although the polymerization initiator is not particularly limited, by selecting and adjusting the polymerization reactivity with the polymerizable monomer, chemical structure, molecular weight, initiator efficiency, etc., the peak area ratio of the polymer resin phase is set to a specific range, The effects of the present invention can be obtained.
Polymerization initiators include radical polymerization initiators that undergo intramolecular cleavage due to various physical factors such as light and heat, or generate hydrogen by extracting hydrogen from other molecules, but without applying heat. A radical photopolymerization initiator that can be polymerized at a temperature equal to or lower than the phase transition temperature of the liquid crystal is preferable in that the thermal effect on the liquid crystal is small.

(Radical photopolymerization initiator)
The radical photopolymerization initiator is not particularly limited in molecular structure, but it is preferable to select a compound that can be dissolved in the chiral nematic liquid crystal that is the host liquid crystal. In addition, since the molecules constituting the liquid crystal composition of the present invention typically have ultraviolet light absorption of a wavelength of 350 nm or less, it is preferable to select a radical polymerization initiator that is radicalized by light having a wavelength of 350 nm or more.

  Examples of radical polymerization initiators include acylphosphine oxides, alkylphenones, titanocenes, polyhalogen compounds, alkyl boron salts of cyanine dyes, and triarylbiimidazoles. Among them, acylphosphine oxides and alkylphenones are radicals. A polymerization initiator is preferable, and an acylphosphine oxide radical polymerization initiator is particularly preferable from the viewpoint of polymerization efficiency.

  Examples of the acylphosphine oxide radical polymerization initiator include known monoacylphosphine oxide derivatives, bisacylphosphine oxide derivatives, and trisacylphosphine oxide derivatives. Examples of commercially available products include monoacylphosphine derivatives such as Lucirin TPO (trade name, manufactured by BASF) and IRGACURE 819 (trade name, manufactured by BASF).

The content of the polymerization initiator in the liquid crystal composition is usually 0.01% by mass or more, preferably 0.05% by mass or more in the liquid crystal composition, and usually 5% by mass or less, preferably 1% by mass or less. By being in this range, the polymerization is sufficient, and the repetition durability of the liquid crystal element obtained from the liquid crystal composition and the haze at the time of transparency tend to be improved.
The content ratio of the liquid crystal in the liquid crystal composition is usually 90% by mass or more, preferably 91% by mass or more in the liquid crystal composition, and is usually 99% by mass or less, preferably 98% by mass or less. . By being in this range, the balance of the transparency and optical response characteristics of the liquid crystal element tends to be obtained.

<Other ingredients>
The liquid crystal composition of the present invention may contain a light stabilizer, an antioxidant, a thickener, a polymerization inhibitor, a photosensitizer, an adhesive, an antifoaming agent, a surfactant and the like. Further, by including a spacer, it is possible to form a gap between substrates of a liquid crystal phase formed by photocuring by a method described later.

<Method for producing liquid crystal composition>
Although the manufacturing method of the liquid-crystal composition of this invention does not have limitation in particular, it can manufacture by mixing a component compound with a well-known stirrer, a shaker, etc. You may heat at the time of mixing. In the case of heating, there is no particular limitation as long as the component compound does not cause a thermal reaction.

<Use of liquid crystal composition>
The liquid crystal composition of the present invention is used as a liquid crystal material by allowing a layer containing the cured product to exist between a pair of substrates arranged to face each other, which will be described later.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by a following example, unless the summary is exceeded.

<Measurement Method of Chiral Nematic Liquid Crystal and Liquid Crystal-Isotropic Phase Transition Temperature (Tni) of Liquid Crystal Composition>
A chiral nematic liquid crystal (liquid crystal alone or a mixture of this and a chiral agent) or a liquid crystal composition was once dissolved, and phase transition or phase separation due to temperature increase was obtained by observing with a polarizing microscope.

<Method for measuring monomer solubility>
A polymerizable monomer was added to the chiral nematic liquid crystal, stirred, and allowed to stand at 4 ° C. for 12 hours to confirm whether it precipitated. The maximum concentration at which precipitation did not occur was defined as the solubility of the polymerizable monomer.

<Method for Measuring Dielectric Anisotropy (Δε) of Liquid Crystal>
The dielectric anisotropy (Δε) of the liquid crystal was determined by Δε = ε1-ε2. ε1 is the dielectric constant in the major axis direction of the liquid crystal molecules, and ε2 is the dielectric constant in the uniaxial direction of the liquid crystal molecules.

The dielectric constant ε (ε1 and ε2) is ε = Cd / S (C represents the capacitance of the liquid crystal. D represents the thickness of the liquid crystal phase. S represents the area of the overlapping portion of the electrodes of the two electrode substrates. It represents.
<Measurement method of pitch length (p) of chiral nematic liquid crystal and liquid crystal composition>
A chiral nematic liquid crystal or a liquid crystal composition is injected into an empty cell having a gap of 10 μm composed of a transparent glass substrate with an electrode layer that has been subjected to a homogeneous alignment treatment, and from a selective reflection wavelength λ measured by a spectrophotometer, p = λ / n (where n was determined from the refractive index of chiral nematic liquid crystal or liquid crystal composition.

<Measurement method of voltage holding ratio (VHR)>
VHR measurement was performed with a liquid crystal physical property evaluation apparatus 6254 type (manufactured by Toyo Technica). A voltage was applied to the VHR evaluation element at 5 V, 60 Hz, and a frame time of 1667 ms, and measurement was performed.

<Measurement method of haze of liquid crystal element>
The haze, parallel light transmittance and response speed of the liquid crystal element of the present invention were measured at room temperature of 25 ° C. Further, the liquid crystal was driven by applying a rectangular wave of 100 Hz, and the measurement voltage was measured using 100 Vp-p.
Haze was measured with a haze meter NDH5000SP (manufactured by Nippon Denshoku).

<Measurement method of response time of liquid crystal element>
The response speed of the liquid crystal element of the invention was measured at room temperature of 25 ° C. Further, the liquid crystal was driven by applying a rectangular wave of 100 Hz, and the measurement voltage was measured using 100 Vp-p.
A halogen lamp was used as the light source and a photodiode was used as the detector. The rise response time and the fall response time when a test waveform was applied while light was vertically incident on the liquid crystal element were measured.

[Example 1]
<VHR evaluation>
A polymerizable monomer represented by the following structural formula (PDLC-005, Hebei Luquan New Type Electronic Materials Co. Ltd.) 95.0 wt% with Tni = 98 ° C. and Δε = 11.8 I) was added at 5.0 wt%, and stirring and filtration were performed to prepare a VHR evaluation solution.

This VHR evaluation liquid was sandwiched by an injection method into a gap of 12.0 μm consisting of two transparent glass substrates with electrode layers subjected to homogeneous orientation treatment, and sealed with an adhesive. After leaving still for 12 hours at 25 ° C., UV exposure at 365 nm was performed at 2400 mJ / cm ² at 30 ° C. to obtain a VHR evaluation element (AI).
For reference, an element was prepared by the same method using the cyano nematic liquid crystal to which no polymerizable monomer was added, and was designated as a VHR evaluation element (A).

The VHR of the VHR evaluation element (A) was 39%, whereas the VHR of (AI) was as high as 45%. It is considered that the photodegradation of the cyano nematic liquid crystal was suppressed by adding the polymerizable monomer (I).
[Example 2]
A VHR evaluation element (A-II) was produced in the same manner as in Example 1 except that the polymerizable monomer was changed to the following structural formula (II).

VHR of the VHR evaluation element (A-II) was 56%. It is considered that the photodegradation of the cyano nematic liquid crystal was suppressed by adding the polymerizable monomer (II).
[Example 3]
A VHR evaluation element (A-III) was produced in the same manner as in Example 1 except that the polymerizable monomer was changed to the following structural formula (III).

VHR of the VHR evaluation element (A-III) was 45%. It is considered that the photodegradation of the cyano nematic liquid crystal was suppressed by adding the polymerizable monomer (III).
[Example 4]
Addition of 5.0 wt% of polymerizable monomer (IV) represented by the following structural formula to 95.0 wt% of cyano nematic liquid crystal (E-8, manufactured by Merck & Co.) having Tni = 70 ° C. and Δε = 15.6 Then, stirring and filtration were performed to prepare a VHR evaluation solution.
Using this VHR evaluation solution, a VHR evaluation element (B-IV) was prepared in the same manner as in Example 1.
For reference, an element was prepared by the same method using the above cyano nematic liquid crystal to which no polymerizable monomer was added, and was used as a VHR evaluation element (B).

The VHR of the VHR evaluation element (B) was 34%, whereas the VHR of (B-IV) was as high as 52%. It is thought that the photodegradation of the cyano nematic liquid crystal was suppressed by adding the polymerizable monomer (IV).
[Example 5]
A VHR evaluation element (BV) was produced in the same manner as in Example 4 except that the polymerizable monomer was changed to the following structural formula (V).

The VHR of the VHR evaluation element (BV) was 56%. It is thought that the photodegradation of the cyano nematic liquid crystal was suppressed by adding the polymerizable monomer (V).
[Comparative Example 1]
A VHR evaluation element (A-VI) was produced in the same manner as in Example 1 except that the polymerizable monomer was changed to the following structural formula (VI).

VHR of the VHR evaluation element (A-VI) was 31%.
[Comparative Example 2]
A VHR evaluation element (A-VII) was produced in the same manner as in Example 1 except that the polymerizable monomer was changed to the following structural formula (VII).

VHR of the VHR evaluation element (A-VII) was 20%.
[Comparative Example 3]
A VHR evaluation element (A-VIII) was produced in the same manner as in Example 1 except that the polymerizable monomer was changed to the following structural formula (VIII).

VHR of the VHR evaluation element (A-VIII) was 6%.
[Comparative Example 4]
A VHR evaluation element (B-VII) was produced in the same manner as in Example 4 except that the polymerizable monomer was changed to the structural formula (VII).
VHR of the VHR evaluation element (B-VII) was 26%.

<Adjustment of chiral nematic liquid crystal>
A chiral nematic liquid crystal (PDLC-005, manufactured by Hebei Luquan New Type Electronic Materials Co. Ltd.) 88.0 wt% with Tni = 98 ° C. and Δε = 11.8 is represented by the following structural formula (IX) 12.0 wt% of an agent (CB-15, manufactured by Merck Japan) was mixed to prepare a chiral nematic liquid crystal (CN1) having Tni = 93.7 ° C. The chiral nematic liquid crystal (CN1) had a pitch length p = 1.2 ± 0.1 μm.

  A chiral agent represented by the following structural formula (X) (CB-15, Merck Japan) is added to 88.0 wt% of a cyano nematic liquid crystal (E-8, manufactured by Merck & Co.) having Tni = 70 ° C. and Δε = 15.6. 12.0 wt% was prepared to prepare a chiral nematic liquid crystal (CN2) with Tni = 68.1 ° C. The chiral nematic liquid crystal (CN2) had a pitch length p = 1.1 ± 0.1 μm.

[Comparative Examples 5 to 7]
Table 1 shows the solubility of the polymerizable monomers (VI) to (VIII) in the chiral nematic liquid crystal (CN1).
[Examples 6 to 8]
Table 1 shows the solubility of the polymerizable monomers (I) to (III) in the chiral nematic liquid crystal (CN1). Any of the polymerizable monomers (I) to (III) showed higher solubility than the polymerizable monomers (VI) to (VIII).

[Comparative Examples 8-9]
Table 2 shows the solubility of the polymerizable monomers (VII) to (VIII) with respect to the chiral nematic liquid crystal (CN2).
[Examples 9 to 10]
Table 2 shows the solubility of the polymerizable monomers (IV) to (V) with respect to the chiral nematic liquid crystal (CN2). All of the polymerizable monomers (IV) to (V) showed higher solubility than the polymerizable monomers (VII) to (VIII).

[Example 11]
95.0 parts by weight of the chiral nematic liquid crystal (CN1), 5.0 parts by weight of the polymerizable monomer represented by the structural formula (I), and a polymerization initiator (Irgacure 819) represented by the following structural formula (X) , Manufactured by BASF JAPAN), 0.03 part by weight, and stirring and filtration were performed to prepare a liquid crystal composition (LC-I) having Tni = 92.4 ° C.

The liquid crystal composition (LC-I) was sandwiched by an injection method in a gap of 12.0 μm consisting of two transparent glass substrates with electrode layers subjected to homogeneous alignment treatment, sealed with an adhesive, and then at 30 ° C. with a thickness of 365 nm. UV exposure was performed at 2600 mJ / cm ^{2 to} produce a liquid crystal element (C-I).
The liquid crystal element (CI) had a haze of 3.3% when the power was turned off, a haze of 96.1% when the power was turned on, a rise response time of 1.8 ms, and a fall response time of 2.1 ms. It was.

[Example 12]
A liquid crystal composition (LC-II) having Tni = 83.0 ° C. was prepared in the same manner as in Example 11 except that the polymerizable monomer was changed to (II). A liquid crystal element (C-II) was produced in the same manner as in Example 11 except that this liquid crystal composition (LC-II) was used.
The liquid crystal element (C-II) had a haze of 3.9% when the power was turned off, a haze of 89.9% when the power was turned on, a rise response time of 1.6 ms, and a fall response time of 1.7 ms. It was.

[Example 13]
In 95.0 parts by weight of the chiral nematic liquid crystal (CN2), 5.0 parts by weight of the polymerizable monomer represented by the structural formula (V) and a polymerization initiator (Irgacure 184) represented by the following structural formula (XI) , Manufactured by BASF JAPAN), 0.45 parts by weight, and stirring and filtration were performed to prepare a liquid crystal composition (LC-III) having Tni = 64.8 ° C.

A liquid crystal element (C-III) was produced in the same manner as in Example 11 using the liquid crystal composition (LC-III).
The liquid crystal element (C-III) had a haze of 5.3% when the power was turned off, a haze of 79.4% when the power was turned on, a rise response time of 1.8 ms, and a fall response time of 2.3 ms. It was.

  From Examples 11 to 13, the liquid crystal element of the present invention has a haze when the power is turned off and a haze when the power is turned on, as compared with known liquid crystal elements described in, for example, International Publication WO2012 / 133445 and International Publication WO2014 / 051002. It was shown that the response time of the rise and the response time of the fall are excellent.

Claims (14)

At least one is a transparent substrate, has a pair of substrates with electrodes arranged opposite to each other, and has a liquid crystal light control layer including a composite including a chiral nematic liquid crystal phase and a polymer resin phase between the substrates A liquid crystal element, wherein the polymer resin phase includes a structure represented by the following general formula (1), and the chiral nematic liquid crystal phase has a positive dielectric anisotropy.

[In general formula (1),
R ¹ and R ² each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent,
X ¹ and X ³ each independently represent a divalent group which may have a substituent,
X ² represents a divalent group which may have a direct bond or a substituent,
A ¹ and A ² each independently have a divalent aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a substituent. An optionally substituted cyclic aliphatic hydrocarbon group, wherein at least one of A ¹ and A ² is a group containing a cyclic aliphatic hydrocarbon group;
m ¹ and m ³ each independently represent an integer of 0 or more and 6 or less,
m ² represents an integer of 0 or more and 4 or less. ] The distance d between the pair of substrates with electrodes arranged opposite to each other is 2 μm or more, 100
2. The liquid crystal device according to claim 1, wherein the relationship is equal to or less than μm, and the relationship between the chiral pitch lengths p and d of the chiral nematic liquid crystal is d / p ≧ 1.   The liquid crystal element according to claim 1, wherein the liquid crystal light control layer is a polymer-stabilized liquid crystal.   The liquid crystal element according to claim 1, which is a transmission-scattering element.   The liquid crystal element according to claim 1, wherein the liquid crystal element does not use a polarizing plate.   6. The liquid crystal device according to claim 1, wherein there is a region where the visible light transmittance when a DC voltage and / or an AC voltage is applied is lower than the visible light transmittance when no voltage is applied. The liquid crystal element as described.   The liquid crystal element according to any one of claims 1 to 6, wherein a haze when a DC voltage and / or an AC voltage is applied is 70% or more, and a haze when no voltage is applied is 15% or less.   In the temperature range of −10 ° C. or higher, the visible light transmittance of the liquid crystal element when no DC voltage and / or AC voltage is applied is 100%, and the visible light transmittance when the DC voltage and / or AC voltage is applied is 0%. When the DC voltage and / or AC voltage is applied, the time from when the DC voltage and / or AC voltage is applied until the visible light transmittance reaches 10%, and the visible light transmittance from when the DC voltage and / or AC voltage is not applied. 8. The liquid crystal element according to claim 1, wherein the time until the value reaches 90% is 8 ms or less.   A screen using the liquid crystal element according to claim 1.   A display using the liquid crystal element according to claim 1. A liquid crystal composition comprising 0.5% by mass or more and 10% by mass or less of a chiral nematic liquid crystal having a positive dielectric anisotropy and a polymerizable monomer represented by the following general formula (3).

[In general formula (3),
R ³ and R ⁴ each independently represents an unsaturated acyl group,
X ⁴ and X ⁶ each independently represent a divalent group that may have a substituent,
X ⁵ represents a divalent group which may have a direct bond or a substituent,
A ³ and A ⁴ each independently have a divalent aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a substituent. An optionally substituted cyclic aliphatic hydrocarbon group, wherein at least one of A ³ and A ⁴ is a group containing a cyclic aliphatic hydrocarbon group;
n ¹ and n ³ each independently represents an integer of 0 or more and 6 or less,
n ² is 0 or an integer of 4 or less. ]   The liquid crystal composition according to claim 11, wherein a chiral pitch length p of the chiral nematic liquid crystal is 0.3 μm or more and 3 μm or less. The liquid crystal composition according to claim 11 or 12, wherein the liquid crystal-isotropic phase transition temperature of the liquid crystal composition is 40 ° C or higher.   A liquid crystal element formed using the liquid crystal composition according to claim 11.