JP6724352B2 - Liquid crystal element, liquid crystal composition, screen and display using liquid crystal element - Google Patents

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 that can switch between a light transmitting state and a light scattering state without using a polarizing plate, a screen and a display using the liquid crystal element.

In recent years, among liquid crystal elements, a transmission-scattering type liquid crystal element that utilizes a refractive index difference 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 has attracted attention because of its high utilization efficiency of visible light.
Examples of the transmission-scattering type liquid crystal device include polymer-stabilized liquid crystals (PSLC) and polymer dispersed liquid crystals (PDLC).
) Is widely known. In the former case, a trace amount of polymer of about 5% by weight is connected in a continuous network in a liquid crystal phase. 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 have been put into practical use as light control shutters for the purpose of protecting design and privacy in windows, doors, partitions and the like of vehicles such as trains and automobiles, business buildings, hospitals and the like. 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, the electro-optical effect in the reverse mode which is transparent when no voltage is applied and operates in a scattering state when a voltage is applied Is desired.

In order to realize this reverse mode transmission-scattering type liquid crystal element, in general, a liquid crystal composition to which a polymerizable monomer is added is photocured while maintaining a transparent state such as homogeneous, planar, homeotropic, and liquid crystal. A method for forming a composite of a polymer resin with a polymer is known. As such a liquid crystal element, PSLC (Polymer Stabilized Cholesteric Texture) that utilizes transmission scattering of visible light due to phase change of chiral nematic liquid crystal having positive dielectric anisotropy as PSLC and negative dielectric anisotropy as PDLC are used. There is known a method of using the liquid crystal. The latter has a problem that the light transmittance is highly dependent on temperature, the viewing angle is highly dependent, or the liquid crystal is expensive. On the other hand, the former is promising because it has the advantages that the light transmittance is less dependent on temperature, the light transmittance is less dependent on the viewing angle, and the response speed of the device is fast.

Patent Documents 1 to 3 disclose transmissive-scattering liquid crystal elements that exhibit high transparency when power is turned off, high scattering when 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 during manufacturing of the liquid crystal element, a problem of impairing the appearance and uniformity of the liquid crystal element occurs. Therefore, a polymerizable monomer having high solubility in the host liquid crystal is selected.

Polymer Sustained Alignment (PSA) is known as a technique similar to PSLC. In the PSA technique, a liquid crystal composition to which a trace amount of a 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 to stabilize liquid crystal alignment. It is known that 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. Further, Patent Document 5 discloses a liquid crystal element that exhibits high solubility of a host monomer in a polymerizable monomer, high-speed response, and high electrical reliability 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 monomer in the polymerizable liquid crystal. Further, the transmission-scattering type liquid crystal element has high transparency when no DC voltage and/or AC voltage is applied (may be referred to as when power is OFF), and when DC voltage and/or AC voltage is applied (power is ON). The characteristics such as high scattering property, high-speed response, and high electrical reliability are required. Heretofore, methods for individually improving these properties have been shown, but methods for satisfying all of them in a balanced manner have 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 orientation 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 Documents 4 and 5 are optimized for PSA technology, cannot switch to a scattering mode, and require members 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 a transmission-scattering type liquid crystal device, high solubility of the polymerizable monomer in the host liquid crystal, high transparency when the liquid crystal device is turned off, high scattering property when the power is turned on, high speed response and high electrical reliability. Either or both were insufficient.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid crystal composition having excellent solubility of a polymerizable monomer in a host liquid crystal. Another object of the present invention is to provide a liquid crystal element which 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 high-speed response. Moreover, it aims at providing the screen and display which have this 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 a liquid crystal light control layer. The inventors have found that the above can be solved and reached the present invention. That is, the gist of the present invention is as follows.
[1] A liquid crystal light control including at least one transparent substrate, a pair of substrates with electrodes arranged to face each other, and a composite containing 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 the general formula (1),
R ¹ and R ² each independently represent a hydrogen atom or an alkyl group having 1 or more and 6 or less 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. Represents a cyclic aliphatic hydrocarbon group which may be present, and 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 substrates of the pair of substrates with electrodes arranged opposite to each other is 2 μm or more, 1
And the relationship between the chiral pitch lengths 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 device according to [1] or [2], wherein the liquid crystal light control layer is a polymer-stabilized liquid crystal.
[4] The liquid crystal device according to any one of [1] to [3], which is a transmission-scattering device.
[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] In the liquid crystal element, 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. 1. The liquid crystal device according to any one of items.
[7] The liquid crystal element according to any one of [1] to [6], which has a haze of 70% or more when a DC voltage and/or an AC voltage is applied and a haze of 15% or less when no voltage is applied. ..
[8] In the temperature range of −10° C. or higher, the visible light transmittance of the liquid crystal element when a DC voltage and/or an AC voltage is not applied is 100%, and the visible light transmittance when a DC voltage and/or an AC voltage is applied. Is normalized to 0%, the time from when a DC voltage and/or AC voltage is applied to when the visible light transmittance reaches 10%, and when the DC voltage and/or AC voltage is not applied 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 device according to any one of [1] to [8].
[10] A display using the liquid crystal device according to any one of [1] to [8].
[11] A liquid crystal containing a chiral nematic liquid crystal having a positive dielectric anisotropy and a polymerizable monomer represented by the following general formula (3) in an amount of 0.5% by mass or more and 10% by mass or less. Composition.

[In general formula (3),
R ³ and R ⁴ each independently represent an unsaturated acyl group,
X ⁴ and X ⁶ each independently represent a divalent group which 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. Represents a cyclic aliphatic hydrocarbon group which may be present, and 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 represent an integer of 0 or more and 6 or less,
n ² represents an integer of 0 or more and 4 or less. ]
[12] The liquid crystal composition according to [11], wherein the chiral nematic liquid crystal has a chiral pitch length p of 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 according to item 1.
[14] A liquid crystal device formed by 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 is excellent in storage stability of the liquid crystal composition and is prevented from precipitating solid components such as the polymerizable monomer at the time of manufacturing a liquid crystal device, and has high productivity. Is obtained.
The liquid crystal device of the present invention has at least one of transparent substrates, a pair of substrates with electrodes arranged facing each other, and a liquid crystal dimming layer composed of a composite of a liquid crystal phase and a polymer resin phase between the substrates. Hold it. Since the polymer resin phase has a specific structure, the liquid crystal element has excellent 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 high-speed response. The liquid crystal device of the present invention is useful for screens, displays and the like because of the above characteristics. For example, it can be used as a visual field blocking element for a window of a building, a partition, or the like. Further, it can 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 the 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 transmitting state and a light scattering state (transmission-scattering type). At least one of the liquid crystal element included in the liquid crystal element is a transparent substrate for switching between the light transmitting state and the light scattering state, and has a pair of substrates with electrodes arranged to face each other, and a liquid crystal phase and a polymer are provided between the substrates. It can be realized by electrically driving a liquid crystal light control layer containing a composite containing a resin phase. As the liquid crystal light control layer, a composite of a transmission-scattering liquid crystal phase and a polymer resin phase, which can switch between a light transmission state and a light scattering state by electric driving, can be used.

It is generally known that a mixture of a plurality of liquid crystalline substances absorbs ultraviolet light to cause a photoreaction of some molecules to generate ionic impurities. Further, 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, in the exposure step of sandwiching the liquid crystal composition containing the liquid crystal and the polymerizable compound between the two electrode substrates and polymerizing the polymerizable compound by exposure to ultraviolet light, the ionic impurities are generated and the electrical conductivity of the liquid crystal element It causes a decrease in reliability.

In the liquid crystal device of the present invention, since the liquid crystal composition has a polymerizable compound having a specific structure, it is possible to reduce ionic impurities generated in the liquid crystal phase due to the exposure process of ultraviolet light, and to reduce the electrical conductivity of the liquid crystal device. It was found that the reliability can be improved.
The liquid crystal element of the present invention can reduce ionic impurities generated in the liquid crystal phase, and the reason why the liquid crystal element is excellent in electrical reliability is that a mixture of liquid crystals or a polymerizable compound generates an active radical by absorbing ultraviolet light, It is presumed that this is because the polymerizable compound having a specific structure efficiently traps and efficiently converts it into a polymerization reaction. Further, in the molecular structure of the polymerizable compound, by incorporating a cyclic structure of an aliphatic hydrocarbon group at a position that reduces or divides the π-electron conjugation, ultraviolet absorption of the polymerizable compound is suppressed, and ionic impurities such as It is speculated that the generation of decomposition products was reduced.

The ionic impurities in the liquid crystal phase are one of the causes of causing a “burn-in” phenomenon that causes a threshold abnormality due to repeated power ON/OFF switching for the liquid crystal element and continuous driving for a long time. When image sticking occurs in a transmission-scattering type liquid crystal element, the haze at the time of turning off the power increases and the transparency deteriorates. Since the liquid crystal element of the present invention can reduce ionic impurities generated in the liquid crystal phase, burn-in can be suppressed, and the transparency when the power is turned off becomes high.

Further, in the liquid crystal element of the present invention, ionic impurities in the liquid crystal phase can be reduced, which is advantageous for electric driving of the liquid crystal element and excellent in high scattering property and high-speed response when the liquid crystal element is powered on.
Further, since the liquid crystal element of the present invention performs optical modulation by switching of light scattering, it is possible to perform display without using a polarizing plate. Therefore, the liquid crystal device of the present invention can have a transmittance of more than 50% and a high light utilization efficiency.

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

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

Further, the electrode surface provided on the substrate is a protective film or alignment film made of an organic compound such as polyimide, polyamide, silicon, or a cyan compound, an inorganic compound such as SiO ₂ , TiO ₂ , or ZrO ₂ , or a mixture thereof. May be entirely or partially covered with. It should be noted that the substrate may be subjected to an alignment treatment so as to align the liquid crystal with respect to the substrate surface, and if the liquid crystal composition in contact has a planar structure, any alignment treatment may be used. I don't mind. For example, both substrates may have a homogeneous orientation, or one may have a homogeneous orientation and the other may have a homeotropic orientation, that is, a so-called hybrid. 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.

Further, a so-called photo-alignment method may be used in the method for producing the alignment film, 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. When the liquid crystal element is manufactured, the alignment treatment of the substrate is not always necessary if the alignment of the unpolymerized liquid crystal composition can be controlled with respect to the substrate surface. That is, the liquid crystal composition of the present invention can be oriented and have a planar structure by a method such as flowing the liquid crystal composition or applying shear stress before photopolymerization.

The opposing substrate may appropriately have an adhesive layer including a resin body that adheres and supports the substrate in the peripheral portion. In addition, the end face of the liquid crystal element or the injection port of the liquid crystal composition in the present invention may be a tape such as an adhesive tape, a thermocompression bonding tape, a thermosetting tape, or/and a thermosetting resin, a photocurable resin, a moisture curing Resin, room temperature curing 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 the internal liquid crystal or the like from seeping out. Further, this sealing may have a function of preventing deterioration of the liquid crystal element at the same time. As a method of protecting the end face at that time, the end face may be entirely covered, or may be made by pouring a curable resin or a thermoplastic resin into the liquid crystal element from the end face to solidify it. You may cover 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 contained in the liquid crystal light control layer between the substrates by being contained as a component of the liquid crystal composition of the present invention, and the spacer may be dispersed on the substrate during assembly of the liquid crystal element or mixed with an adhesive. It may be present in the adhesive layer.

<Liquid crystal light control layer>
The liquid crystal light control layer included in the liquid crystal device 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 higher than a threshold value. The liquid crystal light control layer may be one that drives in a reverse mode in which a light is transmitted when no voltage is applied and a light is scattered when a voltage is applied. It may be a normal mode drive. Further, the memory mode may be driven in which the voltage is applied only when the light transmission state and the light scattering state are switched.

A method for producing a reverse mode liquid crystal element using the liquid crystal composition of the present invention is disclosed in, for example, Japanese Patent Publication No. 06-507505. A method for producing a normal mode liquid crystal element 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 device using the liquid crystal composition of the present invention is disclosed in, for example, Japanese Patent Publication No. 7-507083.

Next, the case of using PSCT as the liquid crystal light control layer and using it in the reverse mode will be described. When no voltage is applied to the liquid crystal element, almost all of the liquid crystal spiral axis is in a planar phase in which it is oriented in a direction 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 undergoes a phase transition to a focal conic phase that is oriented randomly, and becomes a light scattering state. By switching between these two phases, the haze of the liquid crystal element can be controlled.

On the other hand, a case where PDLC is used as the liquid crystal light control layer and is 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 that is oriented randomly due to strong binding by the polymer resin phase, and becomes 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 long axis of the liquid crystal molecule, which has a negative dielectric anisotropy, becomes a homeotropic phase that is oriented in the direction perpendicular to the substrate, and becomes a light transmitting state. ..

The liquid crystal light control layer of the present invention is not limited in the device system such as PSLC and PDLC as long as it contains a chiral nematic liquid crystal phase and a polymer resin phase having a specific molecular structure, and it is possible to obtain high liquid crystal light by using these. It is possible to obtain electrical reliability, high transparency when the power is off, high scattering when the power is on, and high-speed response.
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-like polymer network structure, the ratio of the polymer resin phase to the liquid crystal phase is 10% by mass or less, and the liquid crystal phase in the liquid crystal light control layer is It can be mentioned that the structure is continuously connected. PSLC has a large elastic interaction at the interface between the liquid crystal phase and the polymer resin phase, and has the advantage that the response speed of the falling of the liquid crystal element is faster than other methods. Further, the transparency when no voltage is applied to the liquid crystal element and the 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 effect of the present invention is not impaired. The content of the polymer resin phase in the liquid crystal phase is preferably 10% by mass or less, more preferably 7% by mass or less. Further, it is preferably 0.1% by mass or more, and more preferably 1% by mass or more. When the proportion of the polymer resin phase is 0.1% by mass or more, the polymer resin phase becomes mechanically tough, and the liquid crystal element tends to have excellent repeated durability. Further, since the liquid crystal molecules can undergo sufficient interfacial interaction, the contrast of transmission and scattering of the liquid crystal element and the response speed may be improved. On the other hand, when the proportion of the polymer resin phase is 10% by mass or less, an increase in drive 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, it may contain a pigment. Specifically, it can be used in a state where a dichroic dye is added to and dissolved in the liquid crystal.
When a dye is added to the liquid crystal, the characteristic 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, is electrically measured according to the movement of the liquid crystal molecule. It can be used as a dimming/optical element member that can be controlled as desired. Specifically, the presence of the dye makes it possible to strongly absorb only the component of the specific wavelength or to enhance the scattering, and thus the wavelength anisotropy can be complemented. This makes it possible to design the desired color rendering effect according to the application destination of the device.

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

[In the general formula (1),
R ¹ and R ² are each independently a hydrogen atom or a carbon atom which may have a substituent, 1 or more;
Represents an alkyl group of 6 or less,
X ¹ and X ³ each independently represent a divalent group which may have a substituent, X ² represents a direct bond or a divalent group which may have 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. Represents a cyclic aliphatic hydrocarbon group which may be present, and 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 which may have a substituent, and X ² represents a direct bond or a divalent group which may have 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.
Further, 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. Of 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 completely different, but from the viewpoint of the ease of the production method, the same is preferable.
Examples of the substituent which may have include an alkyl group, an alkoxy group, an alkylcarboxyl group and the like. Among these, an alkyl group and an alkoxy group are preferable from the viewpoint of solubility in liquid crystal.

(Divalent aliphatic hydrocarbon group)
Examples of the aliphatic hydrocarbon group include linear, branched and cyclic divalent aliphatic hydrocarbon groups. 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 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-cyclohexanediyl group, 1,3-cycloheptanediyl group, and 1,4-cycloheptanediyl group.
Further, the carbon number is preferably 4 or more, more preferably 5 or more, and preferably 8 or less, more preferably 7 or less. Within this range, the orientation with the liquid crystal tends not to be disturbed.

(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 monocycle or a condensed ring formed by condensing 2 to 4 of these.

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 further preferably 18 or less. Within this range, the reactivity during polymerization tends to improve.
Specific examples of the aromatic hydrocarbon group include 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 and the like. Groups. 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 monocycle or a condensed ring formed by condensing 2 to 4 of these.
The aromatic heterocyclic group preferably has 6 or more carbon atoms. On the other hand, the carbon number is preferably 30 or less, more preferably 26 or less, and particularly preferably 18 or less. Within this range, the reactivity during polymerization tends to improve.

Specific examples of the aromatic heterocyclic group include a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyrroloimidazole ring, and pyrrolopyrazole. Ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring Groups such as a quinoline ring, an isoquinoline ring, a shinoline ring, a quinoxaline ring, a phenanthridine ring, a benzimidazole ring, a perimidine ring, a quinazoline ring, a quinazolinone ring, and an azulene ring. 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 crystal.

(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. It may represent a cyclic aliphatic hydrocarbon group.
Further, at least one of A ¹ and A ² contains a cyclic aliphatic hydrocarbon group. At least one of A ¹ and A ² contains a cyclic aliphatic hydrocarbon group, thereby suppressing ultraviolet light absorption of the polymerizable compound, reducing decomposition products, and improving electric reliability of the liquid crystal element. To do. The term "containing a cyclic aliphatic hydrocarbon group" may be an aliphatic hydrocarbon group itself, or the aliphatic hydrocarbon group and another group may be linked by a single bond. It may be a structure in which a group hydrocarbon group and another ring structure are condensed.

At least one of A ¹ and A ² may include a cyclic aliphatic hydrocarbon group, and both may have. From the viewpoint of ease of production, ^one of A ¹ and A ² preferably has one.
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-
Examples include cyclohexanediyl group, 1,4-cyclohexanediyl group, 1,1-cycloheptanediyl group, 1,2-cycloheptanediyl group, 1,3-cycloheptanediyl group, and 1,4-cycloheptanediyl group. 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,
A 1,3-cycloheptanediyl group and a 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 the other group are linked by a single bond 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.

(Divalent group in which an aliphatic hydrocarbon group and another ring structure are condensed)
The group in which an aliphatic hydrocarbon group and another 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.

Further, the carbon number is preferably 4 or more, more preferably 5 or more, and preferably 8 or less, more preferably 7 or less. Within this range, the reactivity during polymerization during the formation of the liquid crystal element tends to improve, and the electrical reliability of the liquid crystal element tends to improve.
A ¹ and A ² may have a substituent. For example, an alkyl group, an alkoxy group, an alkylcarboxyl group and the like can be mentioned. Among these, an alkyl group or an alkoxy group is preferable from the viewpoint of solubility in liquid crystal.

(R ³ and R ⁴ )
R ³ and R ⁴ each independently represent 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, 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, from the viewpoint of improving reactivity during polymerization.

The substituent which 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 crystal.

(M ¹ and m ³ )
m ¹ and m ³ each independently represent 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), the structure represented by the following general formula (2) is particularly preferable because the 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 which may have, and the preferred range are also synonymous.
Specific examples of the structure represented by the general formula (1) are shown below, but the present invention is not limited to these as long as the gist thereof is not exceeded.

<Other ingredients>
The polymer resin phase of the present invention contains a polymer resin obtained by polymerizing a polymerizable monomer described below. Other than 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 of the structure represented by the general formula (1) and the other structure included in the liquid crystal device 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, etc. tend to be sufficiently obtained. Further, the upper limit of the structure represented by the above formula (1) is 100% by mass.
Specific examples of other structures include the following, for example.

When the polymer resin contained in the polymer resin phase of the present invention is a copolymer, it may be any of an alternating copolymer, a block copolymer, a random copolymer and a graft copolymer.

<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 chiral nematic liquid crystal of the present invention has a positive dielectric anisotropy, it can be used as a transmissive-scattering element in 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,
It is preferably 5 or more, and more preferably 8 or more in order to reduce the driving voltage of the liquid crystal element. Further, when a polymerization initiator is used, it is preferable that individual molecules constituting the chiral nematic liquid crystal do not have absorption at a wavelength overlapping with the absorption wavelength of the initiator in order to shorten the polymerization time of the polymerizable monomer.

The chiral nematic liquid crystal may be a set of liquid crystal compounds in which the liquid crystal itself exhibits a cholesteric phase, or may be a chiral nematic liquid crystal obtained 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 depending on the purpose to control the chiral pitch length (p) and the liquid crystal-isotropic phase transition temperature (Tni).

As an example, a case of using as a PSCT element in the reverse mode will be described.
In order to shorten the rise response time τ ₁ , it is advantageous to apply a voltage as high 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 substrates with a pair of electrodes provided facing each other is 1 or more. It is more preferably 2 or more, and particularly preferably 4 or more. Further, it is preferably 20 or less, and particularly preferably 12 or less.

The larger d/p, the larger the scattering at the time of driving, and the better the light blocking characteristic. Further, as d/p is larger, the threshold voltage from the focal conic phase to the homeotropic phase is higher, and even if a high voltage is applied, the phase transition does not change to the light transmitting state, and the light scattering state can be maintained. Therefore, the rising response time τ ₁ can be shortened. On the other hand, since the drive voltage of the liquid crystal element (threshold voltage from the planar phase to the focal conic phase) also increases at the same time, it is preferable to keep it within the above range from the viewpoint of achieving both the light-shielding property and energy saving and safety.

The p of the chiral nematic liquid crystal is preferably 0.3 μm or more, more preferably 0.8 μm or more. On the other hand, it is preferably 3 μm or less, more preferably 2 μm or less.
When p is not too small, the driving voltage of the liquid crystal element tends to be suppressed low, and when it is not too large, the contrast tends to be high.
In general, p is inversely proportional to the concentration of the chiral agent, so the concentration of the chiral agent may be determined by back-calculating from the required value of p. When p×n (n is the refractive index of the chiral nematic liquid crystal) is within the visible light wavelength range (380 nm to 800 nm), the finally obtained liquid crystal element becomes colored when no voltage is applied and is outside the visible light range. In the case of, since it becomes colorless and transparent when no voltage is applied, p may be selected according to the purpose.
The distance d between the substrates with a pair of electrodes arranged facing each other of the liquid crystal element of the present invention needs to be p or more 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. Further, it is preferably 100 μm or less, more preferably 20 μm or less.

The light transmittance of the liquid crystal element in the state where no voltage is applied may decrease as d increases, and the response time of the display element may increase. On the other hand, when 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. Within the above range, these requirements can be satisfied in a well-balanced manner.
The Tni of the chiral nematic liquid crystal is preferably 50° C. or higher, more preferably 70° C. or higher since the upper limit of the temperature at which the liquid crystal element can operate is determined by the Tni of the chiral nematic liquid crystal. On the other hand, since the viscosity tends to increase as Tni increases, the temperature is preferably 200°C or lower, more preferably 150°C or lower.

The nematic liquid crystal may be any known one, and there is no particular limitation on the molecular skeleton of the constituent molecule, the substituent, and the molecular weight, and a synthetic product or a commercially available product may be used. 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. Further, when the polymerization initiator is used, it is preferable that the individual molecules formed by the constituent molecules do not have absorption at a wavelength overlapping with the absorption wavelength of the initiator in order to shorten the polymerization time of the polymerizable monomer. Further, various additives may be contained within a range that does not interfere with the dichroic dye and the optical/electrical characteristics of the liquid crystal element.

In the case of using a known liquid crystalline substance, specifically, the Japan Society for the Promotion of Science, Committee 142, “Liquid Crystal Device Handbook”, Nihon Kogyo Shimbun (1989), pages 152 to 192, and the Liquid Crystal Handbook Editorial Committee Volume: "Liquid Crystal Handbook" Maruzen Co., Ltd. (2000), various low levels such as biphenyl-based, phenylcyclohexane-based, cyclohexylcyclohexane-based, alkyl halide-based, and tolan-based as described on pages 260 to 330. Compounds or mixtures of molecular systems can be used. Further, a polymer compound or a mixture as described in “Liquid Crystal Handbook” edited by “Liquid Crystal Handbook”, Maruzen Co., Ltd. (2000), pages 365 to 415, can be used. Examples of the compound constituting the nematic liquid crystal include the following compounds.

As the cholesteric liquid crystal and the 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 commercially available product, and may have liquid crystallinity by itself, or may have a polymerizable functional group. good. Further, it may be dextrorotatory or levorotatory, and a dextrorotatory chiral agent and a levorotatory chiral agent may be used in combination. Further, as a chiral agent, its own dielectric anisotropy is positively large,
It is preferable that the viscosity is low, from the viewpoint of reduction of the driving voltage of the liquid crystal element and the response speed, and it is preferable that the helical twisting power, which is an index of the twisting power of the chiral agent, is large. When a polymerization initiator is used, it preferably has no absorption at a wavelength overlapping 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 ( Examples include trade name Merck Ltd., R-1011 (trade name Merck).
[Method of manufacturing liquid crystal element]
The liquid crystal light control layer of the liquid crystal element of the present invention is, for example, a sealed cell in which an adhesive layer is formed with a photocurable adhesive or the like at the periphery of a pair of electrodes-equipped substrates that are opposed to each other with a spacer interposed therebetween. The liquid crystal composition of the present invention is dipped and injected into the notch of the adhesive layer provided at one or more under normal pressure or vacuum, or the liquid crystal composition is applied onto one of the substrates by using a coater, and then applied. It is formed by sandwiching the other substrate by a known method such as overlapping, and then polymerizing and curing by radiation such as ultraviolet light, visible light, and electron beam. In the case of a plastic film substrate, the substrate with electrodes that is continuously supplied is sandwiched by two rubber rolls and the like, and a mixture of a spacer-containing dispersed liquid crystal and an uncured curable compound is supplied and sandwiched between them. Since it can be photocured continuously, it has high productivity. In any of the methods, when the substrate is not subjected to the alignment treatment, the liquid crystal composition is caused to flow before the photocuring of the uncured liquid crystal composition, or a method such as applying shear stress is applied to the liquid crystal. It is necessary that the composition be oriented to have a planar structure. Specifically, the liquid crystal composition can be made to have a planar structure by injecting the liquid crystal composition of the present invention into a sealed cell that is not 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 having a wavelength of 220 nm or more and 450 nm or less. .. Examples include high pressure mercury lamps, ultra high pressure mercury lamps, halogen lamps, metal halide lamps, UV-LEDs, blue LEDs, white LEDs and the like. In addition, a heat ray cut filter, an ultraviolet ray cut filter, a visible light cut filter, etc. may be used in combination. The light may be irradiated onto at least one surface of the transparent substrate of the liquid crystal element, and when the substrates sandwiching the liquid crystal composition are both transparent, both surfaces may be irradiated with light. The light irradiation may be performed at once or may be performed several times. The so-called PSCOF (Phase Separated Composite Organic Film) (V. Vorflusevand S. Kumar, Science 283, 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 It is ² or more. If the irradiance is too low, the polymerization will not proceed sufficiently. Further, the photopolymerizable liquid crystal composition, usually, 2J / cm ² or more, preferably may be applied to 3J / cm ² or more integrated irradiation dose.

The light irradiation time may be determined according to the radiant intensity of the light source, but from the viewpoint of improving productivity, the light irradiation is usually completed within 200 seconds, preferably within 60 seconds, while the light irradiation time is 10 seconds or longer. Preferably. If the light irradiation time is too short, the repeated durability of the liquid crystal element may be poor. When manufacturing a large-area sheet-shaped liquid crystal element using a plastic film substrate, it is possible to irradiate light continuously while moving the light source or sheet, and adjust 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 in the form of particles in a thin film-like transparent polymer or forms a continuous layer, and the continuous layer shows the best contrast. Is formed.
In the present invention, the temperature at which the liquid crystal composition is polymerized is usually preferably 0°C or higher and 40°C or lower. When the temperature is within the appropriate range, the polymerization reaction tends to proceed easily. Further, the heat accumulated due to the polymerization reaction can suppress the temperature rise of the device, and the polymerization can be carried out at the phase transition temperature of the liquid crystal or lower. Therefore, the liquid crystal alignment is not locally disturbed, and the optical characteristics and driving durability of the liquid crystal element are less likely to be affected.

The liquid crystal element of the present invention is colorless and has excellent transparency. This is compared with a polymer resin used for a known liquid crystal element, and 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 π electron conjugation is reduced or divided. It is presumed that the absorption of light in the visible light wavelength is suppressed by incorporating the cyclic 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 step of the liquid crystal element, and is presumed to reduce the coloring-causing substance.

[Drive of liquid crystal element]
The liquid crystal element of the present invention can switch from a transparent state to a scattering state (opaque state) by applying a voltage or returning from a voltage applied state to a voltage non-applied 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. In addition, the voltage here refers to an alternating current and/or a direct current voltage.

As one of the embodiments of the present invention, a screen using a liquid crystal element capable of switching a light transmission state and a light scattering state as a transparent body is used, and an image projected by a projector or the like is formed when the screen is in the light scattering state. The see-through display is made to be visible. Specifically, when the screen is in the light-scattering state or while the light-transmitting state is changed to the light-scattering state, the projector or the like projects an image on a part or the whole of the liquid screen, and the screen element transmits the light. In the 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 synchronous switching at a speed that cannot be followed by the human eye, when the image is projected on the screen, the image appears to stand out. 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 preferably used.
In order to switch the liquid crystal element in the reverse mode of the present invention from the transparent state to the scattering state, a voltage sufficient for the chiral nematic liquid crystal phase to transition from the planar state to the focal conic state may be applied between the electrodes. There are no particular restrictions on the applied waveform such as direct current, alternating current, pulse, or a composite wave thereof. In the case of a DC voltage, it is 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. In this case, it is possible to switch 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 DC voltage, usually 120 Vp-p or less for AC voltage, preferably 90 Vp-p or less, and maximum value for pulse voltage is 60 V or less, The maximum value is preferably 30 V or less.
Further, the haze of the liquid crystal element of the present invention is when no DC voltage and/or AC voltage is applied (power OFF
15% or less at the time of application), and preferably 70% or more when a DC voltage and/or an AC voltage is applied (when the power is ON). Particularly, it is particularly preferable that the power is OFF at 10% or less and the power is ON at 90% or more. In a room or under a fluorescent lamp, when haze exceeds 15%, cloudiness is conspicuous, and when it is less than 70%, a silhouette over the liquid crystal element tends to be visible.

The parallel light transmittance of the liquid crystal device of the present invention is preferably 75% or more when the power is off and 15% or less when the power is on, particularly preferably 80% or more when the power is off and 10% or less when the power is on. If it is less than 75% in a room or under a fluorescent lamp, it is dim, and if it exceeds 15%, an object in front tends to be seen.
In addition, in the present invention, the haze and the 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 reduced and saturated by voltage application. When standardized, the time until the visible light transmittance becomes 10% when the test waveform (rectangular wave of 100 Hz in this embodiment) is applied (rise response time), and when the test waveform is not applied It is defined as the time until the visible light transmittance reaches 90% (falling response time). The response time is measured by the method described in Examples.

The response time of the liquid crystal element of the present invention is preferably 8 msec or less for both the rising response time and the falling response time, more preferably 5 msec or less, and further preferably 3 msec or less at a temperature of −10° C. or higher. Is particularly preferable. For use as a liquid crystal element, it is preferable that the rising response time and the falling response time are the same.

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, but since the response time tends to be long at low temperature, the operating temperature range is preferably −10° C. or higher, more preferably 0° C. That is all. The temperature is preferably 60°C or lower, more preferably 40°C or lower.

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

The projection system includes front projection and rear projection, and is not particularly limited. For example, a rear projection system shown in Japanese Patent Laid-Open No. 6-82748 or International Publication No. 2009/150579, or a projection using coherent light as a light source shown in Japanese Patent Laid-Open No. 2010-217291. The system can be mentioned.

[Liquid crystal composition]
The liquid crystal composition of the present invention contains a chiral nematic liquid crystal having a positive dielectric anisotropy and a polymerizable monomer represented by the following general formula (3) in an amount of 0.5% by mass or more and 10% by mass or less. Is.

[In general formula (3),
R ³ and R ⁴ each independently represent an unsaturated acyl group,
X ⁴ and X ⁶ each independently represent a divalent group which 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. Represents a cyclic aliphatic hydrocarbon group which may be present, and 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 represent an integer of 0 or more and 6 or less,
n ² represents an integer of 0 or more and 4 or less. ]

In general, a composite of liquid crystal and polymer resin is 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 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 stack in the liquid crystal composition due to the π-π interaction and the solubility in the liquid crystal decreases.

In the liquid crystal composition of the present invention, the solubility in the liquid crystal is improved by using the polymerizable monomer in which the aromatic hydrocarbon ring is introduced at the position where the area of the π-π stacking of the polymerizable monomers is reduced. .. Surprisingly, even when a polymerizable monomer having an aromatic hydrocarbon ring introduced at a position that reduces the area of π-π stacking is used, high transparency at power OFF, high scattering at power 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. Thereby, by reducing the area of π-π stacking of the polymerizable monomers, by suppressing the aggregation of the polymerizable monomers, contributes to the improvement of the solubility in the liquid crystal, storage of the liquid crystal composition, High productivity can be obtained without solid analysis during liquid crystal element processing.

(R ³ and R ⁴ )
R ³ and R ⁴ each independently represent an unsaturated acyl group. The number of types of unsaturated bonds that the unsaturated acyl group has is not particularly limited. The carbon number is not particularly limited, but is preferably 3 or more, more preferably 10 or less, and further preferably 5 or less. Within this range, the reactivity during polymerization tends to improve.

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

(X ⁴ , X ⁵ and X ⁶ )
X ⁴ and X ⁶ each independently represent a divalent group which may have a substituent, and X ⁵ represents a direct bond or a divalent group which may have a substituent. The divalent group is not particularly limited, and examples thereof include the same divalent groups as those described above for X ¹ , X ² and X ³ in the general formula (1).

Among these, an ether bond or an alkylene group is preferable from the viewpoint of improving the solubility in liquid crystal.
The substituent which X ⁴ , X ⁵ and X ⁶ may have is a substituent which the divalent group of X ¹ , X ² and X ^{3 in} the above general formula (1) may have. The same thing is mentioned and a preferable substituent is synonymous.
The combination of X ⁴ , X ⁵ and X ⁶ is not particularly limited and may be the same or partly or totally different, but it is preferable that they are the same from the viewpoint of easy 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 that they may have, preferred ranges and the like 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 alignment regularity with the liquid crystal tends to be excellent.

[In the 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. May represent a cyclic aliphatic hydrocarbon group, at least one of A ¹ and A ² is a group containing a cyclic aliphatic hydrocarbon group,
n ² represents an integer of 0 or more and 2 or less. ]

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 which may have, and the preferred range are also synonymous.
Specific examples of the polymerizable monomer represented by the general formula (3) are shown below. The present invention is not limited to these as long as the gist thereof is not exceeded.

As the polymerizable monomer used in the liquid crystal composition of the present invention, only one type of the polymerizable monomer represented by the general formula (3) may be used, or two or more types may be used in combination. Specifically, another polymerizable monomer having one or more ethylenically unsaturated double bonds such as a (meth)acrylic or vinyl type and one ethylenically unsaturated double bond You may copolymerize with the polymerizable monomer represented by the said Formula (3) by including a polymerizable oligomer which has.

For example, a polymerizable monomer such as a monofunctional (meth)acrylic monomer, a bifunctional (meth)acrylic monomer, and a trifunctional or higher polyfunctional (meth)acrylic monomer described in JP-A-9-90328 (meth). A polymerizable oligomer such as an acrylic oligomer can be used.
Examples of the vinyl monomer 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 other polymerizable monomers is not particularly limited as long as it does not impair the effects of the present invention. Among these, the content of 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 proportion of the polymerizable monomer represented by the general formula (3) is within the appropriate range, it becomes possible to manufacture a liquid crystal element in a short time, and high response, high transparency, high scattering property, and low coloring are obtained. , A liquid crystal element excellent in high durability and deterioration over time tends to be obtained. Further, the upper limit of the polymerizable monomer represented by the general formula (3) is 100% by mass.
When the polymer resin contained in the polymer resin phase of the present invention is a copolymer, it may be any of an alternating copolymer, a block copolymer, a random copolymer and a graft copolymer.

<Chiral nematic liquid crystal>
The chiral nematic liquid crystal contained in the liquid crystal composition of the present invention has the same meaning as the chiral nematic liquid crystal described in the chiral nematic liquid crystal phase of the liquid crystal element, and specific examples, preferable ranges and the like.

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

The ratio of the polymerizable monomer in the liquid crystal composition is 0.5% by mass or more and 10% by mass or less.
It is preferably 7% by mass or less, and particularly preferably 6.5% by mass or less. Further, it is preferably 0.1% by mass or more, and 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 monomers and the non-polymerizable monomers to the liquid crystal composition is usually 0.2% by mass or more, preferably 1. It is 2% by mass or more, while it is usually 10% by mass or less, preferably 7% by mass or less. When this ratio is in an appropriate range, the repeating durability of the liquid crystal element tends not to decrease, and the haze when transparent may not be too large, and the haze when opaque may not decrease.

<Polymerization initiator>
When polymerizing the polymerizable monomer of the present invention, it is preferable to use a polymerization initiator. The polymerization initiator is not particularly limited, the polymerization reactivity with the polymerizable monomer, the chemical structure, the molecular weight, by selecting and adjusting the initiator efficiency, the peak area ratio of the polymer resin phase in a specific range, The effect 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 that generate hydrogen radicals by drawing hydrogen from other molecules. A radical photopolymerization initiator that can be polymerized at a temperature below the phase transition temperature of the liquid crystal is preferable because it has a small thermal effect on the liquid crystal.

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

Examples of radical polymerization initiators include acylphosphine oxide-based, alkylphenone-based, titanocene-based, polyhalogenated compounds, alkylboron salts of cyanine dyes, triarylbiimidazole, and the like. Among them, acylphosphine oxide-based and alkylphenone-based radicals Polymerization initiators are preferable, and acylphosphine oxide-based radical polymerization initiators are particularly preferable from the viewpoint of polymerization efficiency.

As the acylphosphine oxide-based radical polymerization initiator, for example, known monoacylphosphine oxide derivatives, bisacylphosphine oxide derivatives, trisacylphosphine oxide derivatives and the like can be used. 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 ratio of the polymerization initiator in the liquid crystal composition is usually 0.01% by mass or more, preferably 0.05% by mass or more, and usually 5% by mass or less, preferably, in the liquid crystal composition. It is 1 mass% or less. Within this range, the polymerization tends to be sufficient, and the repeating durability of the liquid crystal element obtained from the liquid crystal composition and the haze during 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, and usually 99% by mass or less, preferably 98% by mass or less in the liquid crystal composition. .. Within this range, the balance of 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, a defoaming agent, a surfactant and the like. Further, by including a spacer, a gap between substrates of a liquid crystal phase formed by photo-curing by a method described later can be formed.

<Method for producing liquid crystal composition>
The method for producing the liquid crystal composition of the present invention is not particularly limited, but it can be produced by mixing the component compounds with a known stirrer, shaker or the like. You may heat at the time of mixing. When heating, the temperature is not particularly limited as long as it is a temperature at which the component compounds do 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 including a layer containing the cured product thereof between a pair of substrates of a liquid crystal material, which will be described later, which are arranged to face each other.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

<Method for measuring liquid crystal-isotropic phase transition temperature (Tni) of chiral nematic liquid crystal and liquid crystal composition>
A chiral nematic liquid crystal (liquid crystal alone or a mixture of chiral agent and the same) or a liquid crystal composition was once made compatible with each other, and phase transition or phase separation due to temperature rise was obtained by observing with a polarizing microscope.

<Measurement method of monomer solubility>
The polymerizable monomer was added to the chiral nematic liquid crystal, and the mixture was stirred and allowed to stand at 4° C. for 12 hours to confirm whether or not precipitation occurred. The maximum concentration at which precipitation did not occur was taken as the solubility of the polymerizable monomer.

<Method of measuring dielectric anisotropy (Δε) of liquid crystal>
The dielectric anisotropy (Δε) of the liquid crystal was calculated by Δε=ε1-ε2. ε1 is the dielectric constant in the long axis direction of the liquid crystal molecules, and ε2 is the dielectric constant in the uniaxial direction of the liquid crystal molecules.

The permittivity 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, and S represents the area of the overlapping portion of the electrodes of the two electrode substrates. It represents.
<Method for measuring pitch length (p) of chiral nematic liquid crystal and liquid crystal composition>
A chiral nematic liquid crystal or a liquid crystal composition was injected into an empty cell having a gap of 10 μm and made of a transparent glass substrate with an electrode layer subjected to a homogeneous alignment treatment, and p=λ/n (however, from the selective reflection wavelength λ measured by a spectrophotometer n was determined by the chiral nematic liquid crystal or the refractive index of the liquid crystal composition).

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

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

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

[Example 1]
<VHR evaluation>
In 95.0 wt% of cyano nematic liquid crystal (PDLC-005, manufactured by Hebei Luquan New Type Electronic Materials Co. Ltd) having Tni=98° C. and Δε=11.8, a polymerizable monomer represented by the following structural formula ( 5.0 wt% of I) was added, and the VHR evaluation liquid was adjusted by stirring and filtering.

This VHR evaluation liquid was sandwiched by a pouring method into a gap of 12.0 μm consisting of two transparent glass substrates with an electrode layer subjected to a homogeneous alignment treatment, and was sealed with an adhesive. After standing still at 25° C. for 12 hours, UV exposure at 365 nm was performed at 2400 mJ/cm ² at 30° C. to obtain a VHR evaluation element (AI).
As a reference, an element was prepared by the same method using the cyano nematic liquid crystal to which the polymerizable monomer was not added, and the element was used as a VHR evaluation element (A).

The VHR of the VHR evaluation element (A) was 39%, while the VHR of (AI) was as high as 45%. It is considered that the photo-deterioration 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).

The VHR of the VHR evaluation element (A-II) was 56%. It is considered that the photo-deterioration 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).

The VHR of the VHR evaluation element (A-III) was 45%. It is considered that the photo-deterioration of the cyano nematic liquid crystal was suppressed by adding the polymerizable monomer (III).
[Example 4]
5.0 wt% of a polymerizable monomer (IV) represented by the following structural formula was added to 95.0 wt% of a cyano nematic liquid crystal (E-8, manufactured by Merck) having Tni=70° C. and Δε=15.6. Then, the VHR evaluation liquid was adjusted by stirring and filtering.
Using this VHR evaluation liquid, a VHR evaluation element (B-IV) was prepared in the same manner as in Example 1.
As a reference, an element was prepared by the same method using the above-mentioned cyano nematic liquid crystal to which no polymerizable monomer was added, and a VHR evaluation element (B) was obtained.

The VHR of the VHR evaluation element (B) was 34%, while the VHR of (B-IV) was as high as 52%. It is considered that the photo-deterioration 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 (B-V) was 56%. It is considered that the photo-deterioration 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).

The 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).

The 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).

The 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).
The VHR of the VHR evaluation element (B-VII) was 26%.

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

A chiral agent represented by the following structural formula (X) (CB-15, Merck Japan) was 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 mixed to prepare a chiral nematic liquid crystal (CN2) having Tni=68.1° C. The pitch length p of this chiral nematic liquid crystal (CN2) was p=1.1±0.1 μm.

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

[Comparative Examples 8 to 9]
The solubilities of the polymerizable monomers (VII) to (VIII) in the chiral nematic liquid crystal (CN2) are shown in Table 2.
[Examples 9 to 10]
The solubilities of the polymerizable monomers (IV) to (V) in the chiral nematic liquid crystal (CN2) are shown in Table 2. All of the polymerizable monomers (IV) to (V) showed higher solubility than the polymerizable monomers (VII) to (VIII).

[Example 11]
5.0 parts by weight of the polymerizable monomer represented by the structural formula (I) was added to 95.0 parts by weight of the chiral nematic liquid crystal (CN1), and a polymerization initiator (Irgacure 819) represented by the structural formula (X) below was used. , BASF JAPAN) 0.03 parts by weight was added, and the mixture was stirred and filtered to prepare a liquid crystal composition (LC-I) having Tni=92.4° C.

The above liquid crystal composition (LC-I) was sandwiched by a pouring method into a gap of 12.0 μm composed of two transparent glass substrates with electrode layers subjected to homogeneous alignment treatment by an injection method and sealed with an adhesive. UV exposure was performed at 2600 mJ/cm ^{2 to} prepare a liquid crystal element (C-I).
The liquid crystal element (C-I) had a haze of 3.3% when the power was off, a haze of 96.1% when the power was on, a rising response time of 1.8 ms, and a falling 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 power-off haze of 3.9%, a power-on haze of 89.9%, a rising response time of 1.6 ms, and a falling response time of 1.7 ms. It was

[Example 13]
5.0 parts by weight of the polymerizable monomer represented by the structural formula (V) was added to 95.0 parts by weight of the chiral nematic liquid crystal (CN2), and a polymerization initiator (Irgacure 184) represented by the structural formula (XI) below was used. , BASF JAPAN) 0.45 parts by weight was added, and the mixture was stirred and filtered 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 above liquid crystal composition (LC-III).
The liquid crystal element (C-III) had a power-off haze of 5.3%, a power-on haze of 79.4%, a rising response time of 1.8 ms, and a falling response time of 2.3 ms. It was

From Examples 11 to 13, the liquid crystal element of the present invention is compared with the known liquid crystal elements described in International Publication WO2012/133445 and International Publication WO2014/051002, for example, when the power is turned off and when the power is turned on. , The response time of rising and the response time of falling are excellent.

Claims (14)

At least one is a transparent substrate, has a pair of substrates with electrodes arranged facing each other, and between the substrates, a liquid crystal light control layer containing a complex containing a chiral nematic liquid crystal phase and a polymer resin phase A liquid crystal element, 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 the general formula (1),
R ¹ and R ² are each independently a hydrogen atom or an optionally substituted carbon atom having 1 or more carbon atoms,
Represents an alkyl group of 6 or less,
X ¹ and X ³ each independently represent a divalent group which may have a substituent,
X ² represents a direct bond or a divalent group which may have 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. Represents a cyclic aliphatic hydrocarbon group which may be present, and at least one of A ¹ and A ² is a group shown below,
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. However, when A ¹ is not a group shown below, m ² represents an integer of 1 or more and 4 or less. ]

The distance d between the substrates with a pair of electrodes arranged opposite to each other is 2 μm or more and 100 μm or less, and the relation between the chiral pitch lengths p and d of the chiral nematic liquid crystal is d/p≧1. The liquid crystal device according to claim 1. The liquid crystal device according to claim 1, wherein the liquid crystal light control layer is a polymer-stabilized liquid crystal. The liquid crystal element according to any one of claims 1 to 3, which is a transmission-scattering element. The liquid crystal element according to any one of claims 1 to 4, wherein the liquid crystal element does not use a polarizing plate. 6. The liquid crystal element 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 described. 7. The liquid crystal element according to claim 1, 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 the DC voltage and/or the AC voltage is not applied is 100%, and the visible light transmittance when the DC voltage and/or the AC voltage is applied is 0%. When the DC voltage and/or AC voltage are applied, the visible light transmittance is changed from when the DC voltage and/or AC voltage is applied to when the visible light transmittance becomes 10%. The liquid crystal element according to any one of claims 1 to 7, wherein the time required to reach 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 chiral nematic liquid crystal having a positive dielectric anisotropy and a polymerizable monomer represented by the following general formula (3) are contained in an amount of 5 % by mass or more and 10% by mass or less, for a transmission-scattering element. Liquid crystal composition.

[In general formula (3),
R ³ and R ⁴ each independently represent an unsaturated acyl group,
X ⁴ and X ⁶ each independently represent a divalent group which 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. Represents a cyclic aliphatic hydrocarbon group which may be present,
At least one of A ³ and A ⁴ is a group shown below,
n ¹ and n ³ each independently represent an integer of 0 or more and 6 or less,
n ² represents an integer of 0 or more and 4 or less. However, when A ³ is not a group shown below, n ² represents an integer of 1 or more and 4 or less. ]

The liquid crystal composition according to claim 11, wherein the 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 device formed using the liquid crystal composition according to claim 11.