JPH09329781A - Optical scattering type liquid crystal device and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower the dependence of a driving voltage on temp. by consisting of a polymerizable compsn. consists of a polymerizable compd. with which the driving voltage falls with an increase in temp. and a polymerizable compd. with which the driving voltage rises with the increase in temp. SOLUTION: This optical scattering type liquid crystal device contains at least the polymerizable compd. which forms a transparent high-polymer material constituting the light controllable layer of the optical scattering type liquid crystal device of the driving voltage dropping with the increase in temp. and the transparent high-polymer material constituting the light controllable layer of the optical scattering type liquid crystal device of the driving voltage rising with the increase in temp. as the essential components, although combination use of >=2 kinds of monomers and oligomers is possible even if these monomers and oligomers are polymer forming monomers and oligomers. Two kinds of polymerizable compds. varying in the dependence of the driving voltage on temp. are adjusted in their mixing ratio by taking their temp. characteristics and further, voltage transmittance characteristics into consideration. As a result, the contrast is made high, the driving voltage low and the dependence of the driving voltage on temp. small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a light-scattering type liquid crystal device which can have a large area, and more specifically, it can control the blocking and transmission of light electrically or thermally. , Letters and figures are displayed, and the display is switched electrically with a high-speed response, so that an advertisement board, a guide board,
The present invention relates to a light-scattering liquid crystal device used as a display such as a decorative display plate or a high information display such as a display such as OA equipment.

[0002]

2. Description of the Related Art A large-sized, inexpensive liquid crystal device which does not require a polarizing plate or an alignment treatment and has a good contrast, is disclosed in Japanese Patent Publication No. 58-501631 and US Pat. No. 44350.
Japanese Patent No. 47 discloses a method in which liquid crystal droplets are dispersed in a polymer by encapsulation of the liquid crystal and the polymer is formed into a film. Here, gelatin, gum arabic, polyvinyl alcohol and the like have been proposed as the encapsulating substance.

Liquid crystal molecules encapsulated with polyvinyl alcohol, if they have a positive dielectric anisotropy in a thin layer, are aligned in the direction of the electric field in the presence of an electric field, When the refractive index n0 of the polymer is equal to the refractive index np of the polymer, transparency is exhibited. When the electric field is removed, the liquid crystal returns to the random arrangement and deviates from the refractive index n0 of the liquid crystal droplet, so that the liquid crystal droplet scatters light at the boundary surface and blocks the transmission of light, so the thin layer body becomes cloudy. .

As described above, there are several known techniques for forming a thin film of a polymer containing dispersed liquid crystal droplets. For example, Japanese Patent Publication No. 61-502128 discloses a liquid crystal epoxy resin. A liquid crystal dispersed in a special UV-curable polymer in JP-A-62-1231, and a photo-curable vinyl compound and a liquid crystal in JP-A-63-271233. Of the above (3), the light control layer is formed by utilizing the phase separation of the liquid crystal substance accompanying the photocuring of the photocurable vinyl compound.

Further, in order to enable low voltage driving characteristics and high contrast, which are important characteristics required for practical use of a light-scattering type liquid crystal device, JP-A-1-198725 discloses continuous liquid crystal materials. A technique has been disclosed in which a transparent polymer substance is formed in a layer in a three-dimensional network structure to enable low voltage driving of a liquid crystal device.

[0006]

However, a liquid crystal material including a light-scattering type liquid crystal device having a dimming layer formed by forming a transparent polymer substance having a three-dimensional network structure in a continuous layer of the liquid crystal material. In a light-scattering liquid crystal device composed of a transparent polymer material and a transparent polymer material, there is a problem that the driving voltage has a large temperature dependency and the driving voltage varies depending on the operating temperature.

The problem to be solved by the present invention is to provide a light-scattering liquid crystal device having a dimming layer containing a liquid crystal material and a transparent polymer substance, in which the temperature dependence of the driving voltage is small. To provide.

[0008]

The present inventors have completed the present invention as a result of intensive studies to solve the above problems.

That is, in order to solve the above problems, the present invention has two substrates, at least one of which has an electrode layer and which is transparent, and a light control layer supported between these substrates. A light-scattering liquid crystal device in which the layer contains a liquid crystal material and a transparent polymer substance, wherein the transparent polymer substance has (1) a light control layer of the light-scattering liquid crystal device in which a driving voltage is lowered with an increase in temperature. And a polymerizable compound that forms a transparent polymer substance that forms a transparent polymer substance that forms a transparent polymer substance that forms a light control layer of a light-scattering liquid crystal device in which a driving voltage increases with an increase in temperature. Provided is a light-scattering liquid crystal device, which is a transparent polymer substance composed of a polymerizable composition containing a compound.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The liquid crystal device of the present invention can be manufactured by the following manufacturing method, for example.

That is, (A) a liquid crystal material and (B) (1) a light-scattering type liquid crystal device in which a driving voltage decreases with an increase in temperature between two substrates having at least one transparent electrode layer. A polymerizable compound that forms a transparent polymer material that forms the light layer, and (2) forms a transparent polymer material that forms the light control layer of a light-scattering liquid crystal device in which the driving voltage increases with increasing temperature. Between the two substrates by polymerizing the polymerizable compound by irradiating with ultraviolet rays through a light control layer forming material composed of the polymerizable composition containing the polymerizable compound and (3) a polymerization initiator. A method for manufacturing a light-scattering liquid crystal device, which comprises forming a light control layer containing a liquid crystal material and a transparent solid substance therein.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The substrate used in the present invention may be a rigid material such as glass or metal, or a flexible material such as a plastic film. The two substrates are opposed to each other and are spaced apart from each other at an appropriate interval, at least one of which is transparent, and a substrate containing a liquid crystal material and a transparent polymer substance sandwiched between the two substrates. The light layer must be visible from the outside world. However, complete transparency is not essential.

If the light-scattering liquid crystal device is used to act on light passing from one side of the device to the other, both are provided with appropriate transparency. Appropriate transparent or opaque electrodes may be disposed on the front surface or a part of the substrate depending on the purpose. However, in the case of a flexible material such as plastic, it can be used for the liquid crystal device of the present invention after being fixed to a rigid material such as glass or metal.

Further, a spacer for holding a space can be usually interposed between the two substrates, as in the known light-scattering type liquid crystal device.

As the spacer, for example, Mylar,
Alumina, rod-type glass fiber, glass beads, polymer beads, and other various liquid crystal cells can be used.

The liquid crystal material used in the present invention does not need to be a single liquid crystal compound, and may be a mixture containing two or more kinds of liquid crystal compounds or substances other than the liquid crystal compounds. Any material generally recognized as a liquid crystal material in this technical field may be used, and one having a positive dielectric anisotropy is preferable. As a liquid crystal to be used, a nematic liquid crystal, a smectic liquid crystal, and a cholesteric liquid crystal are preferable, and a nematic liquid crystal is particularly preferable. In order to improve the performance, a cholesteric liquid crystal, a chiral nematic liquid crystal, a chiral smectic liquid crystal or the like, or a chiral compound may be appropriately contained.

The liquid crystal material used in the present invention is preferably a blended composition comprising one or more compounds selected from the compound group shown below, and the characteristics of the liquid crystal material, that is, the resistance value,
For the purpose of improving the phase transition temperature, melting point, viscosity, refractive index anisotropy (Δn), dielectric anisotropy (Δε) of the isotropic liquid and the liquid crystal, and the solubility of the polymerizable composition and the like. Choose appropriately,
It can be used by mixing.

Examples of such liquid crystal materials include benzoic acid ester type, cyclohexylcarboxylic acid ester type, biphenyl type, terphenyl type, phenylcyclohexane type, biphenylcyclohexane type, pyrimidine type, pyridine type, dioxane type, cyclohexane cyclohexane ester type. , Various cyclohexylethane-based, tolan-based, alkenyl-based liquid crystal compounds are used.

Specific examples of the liquid crystal compound include 4-substituted benzoic acid 4′-substituted phenyl ester, 4-substituted cyclohexanecarboxylic acid 4′-substituted phenyl ester, 4-substituted cyclohexanecarboxylic acid 4′-substituted biphenyl ester, 4 -(4-Substituted cyclohexanecarbonyloxy) benzoic acid 4'-substituted phenyl ester, 4- (4-
Substituted cyclohexyl) benzoic acid 4′-cyclohexyl ester, 4-substituted 4′-substituted biphenyl, 4-substituted phenyl 4′-substituted cyclohexane, 4-substituted 4 ″ -substituted terphenyl, 4-substituted biphenyl 4′-substituted cyclohexane, 2 -(4-Substituted phenyl) 5-substituted pyridine, 4-
Examples thereof include substituted (4-substituted phenylethynyl) phenyl.

The content of the liquid crystal material in the light control layer forming material is
A range of 60 to 98% by weight is preferable, and 70 to 90% by weight
Is particularly preferred.

The transparent polymer substance formed in the light control layer may have a structure in which a liquid crystal material is dispersed therein, but one having a three-dimensional network structure is more preferable.

It is preferable that the three-dimensional network structure of the transparent polymer substance is filled with a liquid crystal material, and the liquid crystal material forms a continuous layer, and the optical boundary is formed by forming a disordered state of the liquid crystal material. It forms a surface and develops light scattering.

The transparent polymer substance is not limited to a solid substance, but may be a substance having flexibility, flexibility and elasticity as long as it is suitable for the purpose.

The polymerizable composition used in the present invention is a polymer-forming monomer or oligomer, and two or more kinds of these monomers and oligomers can be used in combination.
At least a polymerizable compound that forms a transparent polymer substance that constitutes the light control layer of a light-scattering liquid crystal device in which the driving voltage decreases with increasing temperature, and a light-scattering type in which the driving voltage increases with increasing temperature. A polymerizable compound that forms a transparent polymer substance that constitutes a light control layer of a liquid crystal device is contained as an essential component. By adjusting the mixing ratio of the two types of polymerizable compounds having different temperature dependences of the driving voltage in consideration of the temperature characteristics and further the voltage transmittance characteristics, the contrast is high, the driving voltage is low, and the driving voltage is high. A light-scattering liquid crystal device in which the temperature dependence of voltage is small can be manufactured.

Examples of the polymerizable compound used in the present invention for forming the transparent polymer substance forming the light control layer of the light-scattering type liquid crystal device in which the driving voltage decreases with an increase in temperature include 2-octyldecyl. Of acrylate, 2-heptylnonyl acrylate, 2-nonylundecyl acrylate, 2-decyldodecyl acrylate, (1,2-hydroxyoctyl-3-octyl-4-hexyl) cyclohexane and 9-nonyl-10-octylnonadecanediol. The diacrylate ester of a mixture etc. are mentioned.

Examples of the polymerizable compound used in the present invention for forming the transparent polymer substance forming the light control layer of the light-scattering liquid crystal device in which the driving voltage increases with an increase in temperature include 2- (3 -Methylbutyl) -7-methyloctyl acrylate, 2- (1-methylbutyl) -5-methyloctyl acrylate, 2- (1-methyl-3-dimethyl) -5-methyl-7-dimethyloctyl acrylate and the like.

Commercially available polymerizable compounds exhibiting the property that the driving voltage increases with increasing temperature include, for example, isomyristyl acrylate IMA (manufactured by Kyoei Yushi Co., Ltd.), isostearyl acrylate ISA (manufactured by Kyoei Yushi Co., Ltd.), Examples include lauryl acrylate LA (manufactured by Kyoei Yushi Co., Ltd.), 2-ethylhexyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), and dimerge acrylate A-OCD (manufactured by Shin Nakamura Chemical Co., Ltd.). Further, a polymerizable compound showing a property that the driving voltage increases with a temperature increase due to a combination of two types, for example,
Neopentyl glycol diacrylate A-NPG (manufactured by Shin-Nakamura Chemical Co., Ltd.) or C9A (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and T
A combination with O-1338 (manufactured by Toa Gosei Co., Ltd.) or TO-1336 (manufactured by Toa Gosei Co., Ltd.) and the like can be mentioned.

A polymerizable compound forming a transparent polymer substance forming a light control layer of a light-scattering type liquid crystal device whose driving voltage decreases with increasing temperature, and light whose driving voltage increases with increasing temperature. Two or more kinds of the polymerizable compounds forming the transparent polymer substance forming the light control layer of the scattering type liquid crystal device may be used in combination.

As a specific method for adjusting the polymerizable composition, first, as an element for producing a transparent polymer substance having an optimum mesh and obtaining a light-scattering liquid crystal device with high contrast, (1,2- Hydroxyoctyl-3-octyl-4-hexyl) cyclohexane and 9-nonyl-10
-Using a bifunctional acrylate such as a diacrylate ester of a mixture of octyl nonadecane diol, and then using 2-octyl decyl acrylate, 2-heptyl nonyl acrylate, 2-nonyl undecyl in order to lower the driving voltage of the light scattering liquid crystal device. A polymerizable composition to which a monofunctional acrylate such as acrylate or 2-decyldodecyl acrylate is added is prepared. A high-contrast, low-voltage driven light-scattering liquid crystal device can be obtained by using this polymerizable composition. However, the polymerizable composition is a light-scattering liquid crystal device in which the driving voltage decreases with an increase in temperature. Since it is a polymerizable compound that forms a transparent polymer material that constitutes the light control layer of a liquid crystal device, the obtained light-scattering liquid crystal device exhibits a characteristic that the driving voltage increases and decreases as the temperature rises.

Therefore, as elements for adjusting the temperature characteristics, 2- (3-methylbutyl) -7-methyloctyl acrylate, 2- (1-methylbutyl) -5-methyloctyl acrylate and 2- (1-methyl-octyl acrylate). 3-
A polymerizable compound such as dimethyl) -5-methyl-7-dimethyloctyl acrylate that forms a transparent polymer substance that forms a light control layer of a light scattering type liquid crystal device in which a driving voltage increases with an increase in temperature. By adding, a light-scattering liquid crystal device having high contrast, low driving voltage, and small temperature characteristics of driving voltage can be obtained.

Depending on the temperature characteristics and voltage transmittance characteristics of the polymerizable composition used in the above adjusting method with respect to the driving voltage, the same effect can be obtained by combining with.

In a light-scattering liquid crystal device in which the driving voltage rises as the temperature rises, the temperature dependence of the driving voltage has a minimum value of the driving voltage with respect to temperature, and below the temperature at which this minimum value is reached, Even with the temperature characteristic adjusting method of the present invention, the temperature characteristic of the driving voltage increases as the temperature drops, and it is difficult to obtain the desired temperature characteristic. There is a temperature range in which the drive voltage rises as the temperature rises above the minimum value temperature of the drive voltage, and the temperature characteristics can be adjusted in that range to reduce the temperature dependence of the drive voltage. Therefore, the minimum value temperature of the driving voltage is important, and it is necessary to appropriately select the combination of the liquid crystal material and the polymerizable compound as necessary to adjust the minimum value temperature of the driving voltage. The temperature at which the driving voltage has a minimum value varies depending on the type of liquid crystal material used and the type of polymerizable compound forming the transparent polymer substance constituting the light scattering liquid crystal device.

Looking at the relationship between the molecular structure and the minimum value temperature of the driving voltage, when the polymerizable compound having a carbon chain in the side chain is used in the polymerizable composition, the minimum value of the driving voltage with respect to the temperature change. Express. Further, in consideration of the low voltage effect of the driving voltage and the light scattering property, when the linear polymerizable compound is used in the polymerizable composition, a material having a carbon chain having 5 or more carbon atoms is preferable, and the carbon chain is As the length increases, the minimum temperature of the drive voltage tends to increase. For example, when a polymerizable compound having a linear carbon chain having 7 carbon atoms is used in the polymerizable composition, the minimum temperature is 0 ° C., and the polymerization having a linear carbon chain having 9 carbon atoms is performed. When the polymerizable compound is used in the polymerizable composition, the minimum temperature is 25 ° C., and when the polymerizable compound having a linear carbon chain having 12 carbon atoms is used in the polymerizable composition, the minimum temperature is Reach 50 ° C.
In particular, when the polymerizable compound having a linear carbon chain having 7 to 9 carbon atoms is used in the polymerizable composition, the minimum value of the driving voltage is smaller than that when other compounds are used. Is more preferable.

On the other hand, when a polymerizable compound having a branched side chain is used in the polymerizable composition, the relationship between the length of the carbon chain and the minimum temperature as in the linear polymerizable compound is not confirmed. However, the effect of suppressing the increase of the driving voltage at room temperature or lower, or the effect of increasing the driving voltage with the temperature increase is recognized.

In the liquid crystal device of the present invention, in order to adjust the temperature characteristic of the driving voltage, it is preferable to use a branched side chain polymerizable compound having an effect of increasing the driving voltage with increasing temperature. Further, when two kinds of polymerizable compounds exhibiting different minimum values are used, the minimum value of the driving voltage is found between the two minimum values. In addition, when a polymerizable compound that does not exhibit a minimum driving voltage temperature by itself is used, it may exhibit a minimum driving voltage value when combined with another polymerizable compound having a side chain with similar properties. It is influenced by the side chain morphology, length, side chain ratio, etc. in the copolymer. Further, in the light control layer constituting the light scattering type device, the driving voltage is also determined from the content of the liquid crystal material and the concentration of the polymerizable compound showing the minimum value of the driving voltage contained in the transparent polymer substance forming the light control layer. The minimum temperature of is affected. For example, the liquid crystal concentration is 70% and the minimum temperature is 20.
In the case of ℃, the minimum temperature rises to 25 ℃ when the liquid crystal concentration is set to 75%. When the concentration of the polymerizable compound showing the minimum value temperature of the driving voltage is 17.5% and the minimum value temperature is 25 ° C., the minimum value temperature is lowered to 5 ° C. when the concentration of the polymerizable compound is set to 12.5%. To do.

As described above, in order to adjust the temperature of the minimum value of the driving voltage, 1) the liquid crystal concentration, 2) the concentration of the polymerizable compound showing the minimum value of the driving voltage, and 3) the minimum value of the driving voltage with the liquid crystal material are set. The minimum temperature can be adjusted by changing the type of the polymerizable compound and the combination thereof, and the minimum temperature can be adjusted by appropriately selecting these means as necessary.

Looking at the relationship between the liquid crystal material and the minimum value of the driving voltage, it is affected by the polarity of the liquid crystal material. For example, when a liquid crystal having a high polarity such as a cyano liquid crystal is used, the driving voltage only monotonously decreases as the temperature rises, and a minimum value is not recognized in the temperature characteristic of the driving voltage. On the other hand, when a fluorine-based liquid crystal with a small polarity is used, a minimum value is recognized in the temperature characteristic of the drive voltage, and if the dielectric constant ε⊥ of the vertical component of the liquid crystal material is small, the effect of lowering the minimum value of the drive voltage with respect to temperature is great. Therefore, the temperature characteristics can be adjusted by driving at a low voltage. Therefore, at least the dielectric constant ε⊥ is 5.5.
When the following liquid crystals are used, the temperature characteristic of the driving voltage is small and a minimum value appears, which is preferable. Further, the minimum temperature of the driving voltage can be adjusted by adding a liquid crystal material exhibiting the minimum temperature.

One of the factors that the driving voltage shows a minimum value and the driving voltage increases as the temperature rises is due to the interaction between the liquid crystal molecules and the transparent polymer substance used in the light control layer. In particular, it is strongly influenced by the temperature change of the pretilt angle induced at the interface between the transparent polymer substance of the light control layer and the liquid crystal material. The pretilt angle is maximized near a temperature at which the drive voltage has a minimum value with respect to the temperature, and at this time, the threshold voltage of the liquid crystal is minimized and the drive voltage has a minimum value. When the temperature rises from the minimum value temperature of the driving voltage, the induced pretilt angle gradually decreases, and with this decrease, the threshold value of the liquid crystal increases and the driving voltage increases. The phenomenon of the change in the pretilt angle with temperature is observed from the measurement of the capacitance below the liquid crystal threshold voltage and the measurement of the transmittance with respect to the temperature. It can also be seen from the temperature change of the capacitance of a parallel alignment cell using a polymerizable compound as an alignment film. In the liquid crystal device, the capacitance of the liquid crystal device increases little by little as the temperature decreases toward the minimum value temperature of the driving voltage,
It rapidly increases near the minimum temperature of the driving voltage. this is,
In the state where the liquid crystal molecules are arbitrarily aligned in the light control layer, the component that makes the alignment of the liquid crystal molecules parallel to the electric field direction between the electrodes increases, and the alignment of the liquid crystal molecules is affected by the interface of the transparent polymer substance. It comes from the change in direction. Further, when compared with the temperature characteristic of the minimum transmittance, the minimum transmittance also increases at the same time when the capacitance rapidly increases.

From these points, the change caused by the change in the liquid crystal orientation on the interface of the transparent polymer appears in the temperature change of the minimum transmittance and the temperature change of the capacitance below the threshold voltage. Since a similar phenomenon in which the capacitance below the liquid crystal threshold voltage similarly increases with decreasing temperature is also observed in a parallel alignment cell using the same transparent polymer substance as an alignment film, It can be understood that this is due to the change in orientation accompanying the induction of the pretilt angle.

That is, the polymerizable compound forming the transparent polymer substance forming the dimming layer of the light-scattering liquid crystal device in which the driving voltage rises as the temperature rises is induced at the interface with the liquid crystal as the temperature drops. As long as the pretilt angle is increased, the polymerizable compound and the liquid crystal material may be adjusted so that the temperature at which the induced pretilt angle is maximized is set to be equal to or lower than the lower limit of the practical operating temperature range of the liquid crystal device. Also,
Below the minimum value temperature of the driving voltage, the hysteresis width of the voltage transmittance characteristic increases and the light scattering property decreases, so it is preferable to drive the liquid crystal device of the present invention above the minimum value temperature.

Examples of the polymerization initiator include 2-hydroxy-2-methyl-1-phenylpropan-1-one (“Darocur 1173” manufactured by Merck), 1-hydroxycyclohexyl phenyl ketone (“Ciba Geigy” manufactured by Ciba Geigy). Irgacure 184 "), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1-
On (Merck & Co. "Darocur 1116"), 2-methyl-1- [methylthio) phenyl] -2-morpholinopropane-1 (Ciba Geigy "Irgacure 90"
7 "), benzyl dimethyl ketal (" Irgacure 651 "manufactured by Ciba-Geigy), 2,4-diethylthioxanthone (" Kayacure DETX "manufactured by Nippon Kayaku Co., Ltd.), and ethyl p-dimethylaminobenzoate (Nippon Kayaku Co., Ltd.) Mixture with "Kayacure EPA", isopropyl thioxanthone ("Cantacure-I" manufactured by Ward Prekinsop Co., Ltd.)
TX ") and a mixture of ethyl p-dimethylaminobenzoate, acylphosphine oxide (" Lucirin TPO "manufactured by BASF), and the like.

The proportion of the polymerization initiator used is preferably 0.1 to 10.0% by weight based on the total amount of the polymerizable composition.

In order to interpose the light control layer forming material between the two substrates, this light control layer forming material may be injected between the substrates. However, a suitable solution coater or spin coater may be provided on one of the substrates. It is also possible to apply evenly by using the above, and then press the other substrate one on top of another for pressure bonding.

Further, after applying the light control layer forming material on one substrate to a uniform thickness and supplying the polymerization energy to polymerize and cure the polymerizable composition to form the light control layer, the other The method for manufacturing a light-scattering liquid crystal device in which the above substrates are bonded together is also effective.

The energy for polymerization may be any energy as long as the polymerizable composition can be appropriately polymerized, and examples thereof include radiation such as ultraviolet rays, visible rays, electron beams, and heat.

The method using ultraviolet rays is particularly preferable. Further, it is preferable to irradiate with ultraviolet rays while maintaining the isotropic liquid state of the light control layer forming material in order to form a uniform light control layer.

In order to polymerize the polymerizable composition in the liquid crystal material, light intensity and irradiation dose above a certain level are required, which is the reactivity of the polymerizable composition and the kind of the photopolymerization initiator. Depending on the concentration, it is possible to form a three-dimensional mesh structure and make the mesh size uniform by selecting an appropriate light intensity.

Further, the uniform irradiation in terms of time and plane means that the polymerizable composition interposed between the substrates is instantaneously irradiated with strong light to proceed with the polymerization, thereby making the size of the mesh uniform. It is effective in That is, by irradiating the pulse with ultraviolet light at an appropriate intensity, a transparent polymer substance having a uniform three-dimensional network structure can be formed in the liquid crystal.

[0049]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. However, the invention is not limited to these examples.

In the following examples, each of the evaluation characteristics means the following symbols and contents. T0: White turbidity; Light transmittance (%) when applied voltage is 0. T100: Transparency; Light transmittance (%) when applied voltage is increased and light transmittance almost stops V90: Driving voltage; Applied voltage (Vrms) at which the light transmittance becomes 90% when T0 is 0% and T100 is 100%.

<Example 1> (Liquid crystal material) Liquid crystal composition A having the following composition: 76.0% by weight (Polymerizable compound) "KU-760" 11.76% by weight ((1,2 manufactured by Arakawa Chemical Co., Ltd. -Hydroxyoctyl-3-octyl-4-hexyl) cyclohexane and diacrylate of a mixture of 9-nonyl-10-octylnonadecanediol) "TO1338" 9.41% by weight (2, manufactured by Toagosei Co., Ltd. Nonylundecyl acrylate) "IS-A" 2.35% by weight (2- (1-methyl-3-dimethyl) -5-methyl-7-dimethyloctyl acrylate manufactured by Kyoei Chemical Co., Ltd. = isostearyl acrylate) (polymerization initiation) Agent) A dimming layer forming material consisting of 0.48% by weight of "Irgacure 651" (benzyl dimethyl ketal manufactured by Ciba-Geigy Co., Ltd.) was added in an amount of 11.0 μm. It is sandwiched between two ITO electrode glass substrates coated with the glass fiber spacers described above, and while maintaining the temperature at which the light control layer forming material becomes an isotropic liquid state, ultraviolet rays of 20 mW / cm ² are applied at 60
The polymerizable compound was cured by irradiation for 2 seconds to obtain a light-scattering type liquid crystal device having a light control layer of a thickness of 11.0 μm made of a liquid crystal material and a transparent polymer substance.

When the light control layer of the light-scattering liquid crystal device thus obtained was observed with an electron microscope, a transparent solid substance having a three-dimensional network could be confirmed.

Next, the voltage-transmittance characteristics of the light-scattering type liquid crystal device thus obtained at 25 ° C., 30 ° C. and 40 ° C. were measured, and the following characteristics were shown at each measurement temperature. 25 ° C T0 = 2.7%, T100 = 90.0%, V90
= 4.7Vrms 30 ° C T0 = 2.7%, T100 = 89.5%, V90
= 4.7Vrms 40 ° C T0 = 3.1%, T100 = 89.4%, V90
= 4.7Vrms

(Composition of liquid crystal composition A)

Embedded image

Comparative Example 1 (Liquid Crystal Material) Liquid Crystal Composition A Used in Example 1 76.0% by Weight (Polymerizable Compound) "KU-760" (Diacrylate manufactured by Arakawa Chemical Co., Ltd.) 23.52% by weight % (Polymerization initiator) “Irgacure 651” (manufactured by Ciba Geigy) 0.48% by weight of the light control layer forming material is sandwiched between two ITO electrode glass substrates coated with 11.0 μm glass fiber spacers, While maintaining the temperature so that the material for forming the light control layer becomes an isotropic liquid state, 6 mW of UV light of 20 mW / cm ² was applied.
The polymerizable compound was cured by irradiation for 0 seconds to obtain a light-scattering type liquid crystal device having a light control layer made of a liquid crystal material and a transparent polymer substance and having a thickness of 11.0 μm.

When the light control layer of the light-scattering liquid crystal device thus obtained was observed with an electron microscope, a transparent solid substance having a three-dimensional network could be confirmed.

Next, as a result of measuring the voltage transmittance characteristics of the light-scattering type liquid crystal device thus obtained at 25 ° C., 30 ° C. and 40 ° C., the following characteristics were shown at each measurement temperature. 25 ° C T0 = 1.8%, T100 = 84.5%, V90
= 25.5Vrms 30 ° C T0 = 1.8%, T100 = 85.3%, V90
= 24.3Vrms 40 ° C T0 = 2.0%, T100 = 85.3%, V90
= 22.2 Vrms

Comparative Example 2 (Liquid Crystal Material) Liquid Crystal Composition A Used in Example 1 76.0% by Weight (Polymerizable Compound) “KU-760” (Diacrylate manufactured by Arakawa Chemical Co., Ltd.) 11.76% by weight % "TO1338" 11.76% by weight (2-nonylundecyl acrylate manufactured by Toagosei Co., Ltd.) (Polymerization initiator) 0.48% by weight of a dimming layer forming material "IRGACURE 651" (manufactured by Ciba Geigy) It is sandwiched between two ITO electrode glass substrates coated with 11.0 μm glass fiber spacers, and while maintaining the temperature so that the light control layer forming material becomes an isotropic liquid state, 20 mW / cm ² of UV light is applied to the substrate.
The polymerizable compound was cured by irradiation for 0 seconds to obtain a light-scattering type liquid crystal device having a light control layer made of a liquid crystal material and a transparent polymer substance and having a thickness of 11.0 μm.

When the light control layer of the light-scattering liquid crystal device thus obtained was observed with an electron microscope, a transparent solid substance having a three-dimensional network could be confirmed.

Next, the voltage-transmittance characteristics of the light-scattering type liquid crystal device thus obtained at 25 ° C., 30 ° C. and 40 ° C. were measured, and the following characteristics were shown at each measurement temperature. 25 ° C T0 = 2.5%, T100 = 89.4%, V90
= 5.3Vrms 30 ° C T0 = 2.5%, T100 = 88.6%, V90
= 5.1Vrms 40 ° C T0 = 3.0%, T100 = 89.4%, V90
= 4.8Vrms

The liquid crystal devices obtained in Example 1 and Comparative Examples 1 and 2 and the evaluation results thereof are summarized in Table 1 below.

[0062]

[Table 1]

From the results shown in Table 1, it is possible to reduce the temperature dependence of the driving voltage of the obtained light scattering type liquid crystal device by adjusting the mixing ratio of the polymerizable compounds having different temperature characteristics with respect to the driving voltage. Can understand.

The following second and subsequent embodiments show examples in which the temperature dependency of the drive voltage is eliminated by the above adjusting method.

<Example 2> (Liquid crystal material) Liquid crystal composition A used in Example 1 75.0% by weight (Polymerizable compound) "KU-760" (diacrylate manufactured by Arakawa Chemical Co., Ltd.) 11.03% by weight % "TO1338" 9.80% by weight (2-nonylundecyl acrylate manufactured by Toagosei Kagaku) "IM-A" 3.68% by weight (2- (3-methylbutyl) -7-methyl manufactured by Kyoei Chemical Co., Ltd. Octyl acrylate = isomyristyl acrylate) (Polymerization initiator) "Irgacure 651" (manufactured by Ciba-Geigy) 0.49% by weight of the light control layer forming material coated with 11.0 μm glass fiber spacers It is sandwiched between the ITO electrode glass substrates of, and while maintaining the temperature at which the light control layer forming material becomes an isotropic liquid state, ultraviolet rays of 20 mW / cm ² are applied at 60
The polymerizable compound was cured by irradiation for 2 seconds to obtain a light-scattering type liquid crystal device having a light control layer of a thickness of 11.0 μm made of a liquid crystal material and a transparent polymer substance.

When the light control layer of the light-scattering type liquid crystal device thus obtained was observed with an electron microscope, a transparent solid substance having a three-dimensional network could be confirmed.

Next, as a result of measuring the voltage transmittance characteristics of the light-scattering type liquid crystal device thus obtained at 25 ° C., 30 ° C. and 40 ° C., the following characteristics were shown at each measurement temperature. 25 ° C T0 = 3.1%, T100 = 90.1%, V90
= 4.6Vrms 30 ° C T0 = 3.2%, T100 = 90.2%, V90
= 4.6Vrms 40 ° C T0 = 3.5%, T100 = 89.5%, V90
= 4.6 Vrms

<Example 3> (Liquid crystal material) Liquid crystal composition A used in Example 1 75.0% by weight (Polymerizable compound) "KU-760" (diacrylate manufactured by Arakawa Chemical Co., Ltd.) 11.03% by weight % "TO1336" 12.25% by weight (2-heptylnonyl acrylate manufactured by Toagosei Co., Ltd.) "IM-A" 1.23% by weight (isomyristyl acrylate manufactured by Kyoei Chemical Co., Ltd.) (Polymerization initiator) "Irgacure 651" (Manufactured by Ciba-Geigy) A dimming layer forming material consisting of 0.49% by weight is sandwiched between two ITO electrode glass substrates coated with a 11.0 μm glass fiber spacer to make the dimming layer forming material isotropic. While maintaining the liquid temperature, 60 mW of UV light of 20 mW / cm ²
The polymerizable compound was cured by irradiation for 2 seconds to obtain a light-scattering type liquid crystal device having a light control layer of a thickness of 11.0 μm made of a liquid crystal material and a transparent polymer substance.

When the light control layer of the light-scattering type liquid crystal device thus obtained was observed with an electron microscope, a transparent solid substance having a three-dimensional network could be confirmed.

Next, as a result of measuring the voltage transmittance characteristics of the light-scattering type liquid crystal device thus obtained at 25 ° C., 30 ° C. and 40 ° C., the following characteristics were shown at each measurement temperature. 25 ° C T0 = 2.0%, T100 = 90.2%, V90
= 4.8Vrms 30 ° C T0 = 2.0%, T100 = 90.2%, V90
= 4.8Vrms 40 ° C T0 = 2.4%, T100 = 90.0%, V90
= 4.8Vrms

Comparative Example 3 (Liquid Crystal Material) Liquid Crystal Composition A Used in Example 1 76.0% by Weight (Polymerizable Compound) “KU-760” (Diacrylate manufactured by Arakawa Chemical Co., Ltd.) 14.12% by weight % “TO1336” (monoacrylate manufactured by Toagosei Co., Ltd.) 9.41% by weight (polymerization initiator) “Irgacure 651” (manufactured by Ciba-Geigy) 0.47% by weight of the light control layer forming material of 11.0 μm It is sandwiched between two ITO electrode glass substrates coated with glass fiber spacers, and while maintaining the temperature at which the material for forming the light control layer becomes an isotropic liquid state, ultraviolet rays of 20 mW / cm ² are applied at 60
The polymerizable compound was cured by irradiation for 2 seconds to obtain a light-scattering type liquid crystal device having a light control layer of a thickness of 11.0 μm made of a liquid crystal material and a transparent polymer substance.

When the light control layer of the light-scattering type liquid crystal device thus obtained was observed with an electron microscope, a transparent solid substance having a three-dimensional network could be confirmed.

Next, as a result of measuring the voltage transmittance characteristics of the light scattering type liquid crystal device thus obtained at 25 ° C., 30 ° C. and 40 ° C., the following characteristics were shown at each measurement temperature. 25 ° C T0 = 2.0%, T100 = 89.2%, V90
= 10.3Vrms 30 ° C T0 = 2.0%, T100 = 90.0%, V90
= 9.9Vrms 40 ° C T0 = 2.4%, T100 = 89.7%, V90
= 9.3Vrms

<Example 4> (Liquid crystal material) Liquid crystal composition A used in Example 1 75.0% by weight (Polymerizable compound) "KU-760" (diacrylate manufactured by Arakawa Chemical Co., Ltd.) 11.03% by weight % "ISA" 12.25% by weight (2-Ocryldecyl acrylate manufactured by Shin-Nakamura Chemical Co., Ltd.) 1.23% by weight (isomyristyl acrylate manufactured by Kyoei Chemical Co., Ltd.) (Polymerization initiator) "Irgacure 651" (Manufactured by Ciba-Geigy) 0.49% by weight of the light control layer forming material is sandwiched between two ITO electrode glass substrates coated with 11.0 μm glass fiber spacers, and the light control layer forming material is isotropic. while maintaining the temperature at which the sexual liquid state, the ultraviolet 20 mW / cm ² 60
The polymerizable compound was cured by irradiation for 2 seconds to obtain a light-scattering type liquid crystal device having a light control layer of a thickness of 11.0 μm made of a liquid crystal material and a transparent polymer substance.

When the light control layer of the light-scattering type liquid crystal device thus obtained was observed with an electron microscope, a transparent solid substance having a three-dimensional network could be confirmed.

Next, as a result of measuring the voltage transmittance characteristics of the light-scattering type liquid crystal device thus obtained at 25 ° C., 30 ° C. and 40 ° C., the following characteristics were shown at each measurement temperature. 25 ° C T0 = 2.0%, T100 = 90.1%, V90
= 4.5Vrms 30 ° C T0 = 2.0%, T100 = 90.2%, V90
= 4.5Vrms 40 ° C T0 = 2.3%, T100 = 90.0%, V90
= 4.5Vrms

<Comparative Example 4> (Liquid crystal material) Liquid crystal composition A used in Example 1 75.0% by weight (Polymerizable compound) "KU-760" (diacrylate manufactured by Arakawa Chemical Co., Ltd.) 11.03% by weight % "ISA" 13.48% by weight (2-octyldecyl acrylate manufactured by Shin-Nakamura Chemical Co., Ltd.) (Polymerization initiator) "Irgacure 651" (manufactured by Ciba Geigy) 0.49% by weight was used as a light control layer forming material. It is sandwiched between two ITO electrode glass substrates coated with a glass fiber spacer of 0.0 μm, and while maintaining the temperature at which the light control layer forming material becomes an isotropic liquid state, an ultraviolet ray of 20 mW / cm ² is applied to 60 μm.
The polymerizable compound was cured by irradiation for 2 seconds to obtain a light-scattering type liquid crystal device having a light control layer of a thickness of 11.0 μm made of a liquid crystal material and a transparent polymer substance.

When the light control layer of the light-scattering type liquid crystal device thus obtained was observed with an electron microscope, a transparent solid substance having a three-dimensional network could be confirmed.

Next, as a result of measuring the voltage transmittance characteristics of the light scattering type liquid crystal device thus obtained at 25 ° C., 30 ° C. and 40 ° C., the following characteristics were shown at each measurement temperature. 25 ° C T0 = 2.5%, T100 = 89.5%, V90
= 4.1Vrms 30 ° C T0 = 2.6%, T100 = 89.9%, V90
= 4.0Vrms 40 ° C T0 = 3.0%, T100 = 89.9%, V90
= 3.8 Vrms

<Example 5> (Liquid crystal material) Liquid crystal composition A used in Example 1 74.0% by weight (Polymerizable compound) "KU-760" (diacrylate manufactured by Arakawa Chemical Co., Ltd.) 11.47% by weight % "TO1339" 8.92% by weight (2-nonylundecyl acrylate manufactured by Toagosei Kagaku) "IM-A" 5.10% by weight (isomyristyl acrylate manufactured by Kyoei Chemical) (polymerization initiator) "Irgacure 651 ”(manufactured by Ciba Geigy) 0.51% by weight of the light control layer forming material is sandwiched between two ITO electrode glass substrates coated with 11.0 μm glass fiber spacers to form the light control layer forming material. While maintaining the temperature at which the liquid becomes an isotropic liquid, 60 mW of UV light of 20 mW / cm ²
The polymerizable compound was cured by irradiation for 2 seconds to obtain a light-scattering type liquid crystal device having a light control layer of a thickness of 11.0 μm made of a liquid crystal material and a transparent polymer substance.

When the light control layer of the light-scattering type liquid crystal device thus obtained was observed with an electron microscope, a transparent solid substance having a three-dimensional network could be confirmed.

Next, as a result of measuring the voltage transmittance characteristics of the thus obtained light scattering type liquid crystal device at 25 ° C., 30 ° C. and 40 ° C., the following characteristics were shown at each measurement temperature. 25 ° C T0 = 2.3%, T100 = 90.0%, V90
= 4.9Vrms 30 ° C T0 = 2.3%, T100 = 89.7%, V90
= 4.9Vrms 40 ° C T0 = 2.7%, T100 = 90.1%, V90
= 4.9Vrms

Comparative Example 7 (Liquid Crystal Material) Liquid Crystal Composition A Used in Example 1 76.0% by Weight (Polymerizable Compound) “KU-760” (Diacrylate manufactured by Arakawa Chemical Co., Ltd.) 14.12% by weight % “TO1339” (monoacrylate manufactured by Toagosei Co., Ltd.) 9.41% by weight (polymerization initiator) “Irgacure 651” (manufactured by Ciba Geigy) 0.47% by weight is used as a light control layer forming material of 11.0 μm. It is sandwiched between two ITO electrode glass substrates coated with the glass fiber spacers described above, and while maintaining the temperature at which the light control layer forming material becomes an isotropic liquid state, ultraviolet rays of 20 mW / cm ² are applied at 60
The polymerizable compound was cured by irradiation for 2 seconds to obtain a light-scattering type liquid crystal device having a light control layer of a thickness of 11.0 μm made of a liquid crystal material and a transparent polymer substance.

When the light control layer of the light-scattering type liquid crystal device thus obtained was observed with an electron microscope, a transparent solid substance having a three-dimensional network could be confirmed.

Next, as a result of measuring the voltage transmittance characteristics of the light-scattering type liquid crystal device thus obtained at 25 ° C., 30 ° C. and 40 ° C., the following characteristics were shown at each measurement temperature. 25 ° C T0 = 2.1%, T100 = 90.0%, V90
= 11.0Vrms 30 ° C T0 = 2.1%, T100 = 90.1%, V90
= 10.5 Vrms 40 ° C. T0 = 2.4%, T100 = 89.6%, V90
= 9.7Vrms

<Example 6> Polymerizable compound "IS-A"
(Kyoei Chemical Co., Ltd. 2- (1-methyl-3-dimethyl)-
5-methyl-7-dimethyloctyl acrylate =
Isostearyl acrylate) 97.0% by weight and polymerization initiator "IRGACURE 651" (manufactured by Ciba Geigy) 3
% Of the solution was dropped on two ITO glass substrates, and then spin coated under the conditions of 700 seconds for 30 seconds and 5000 rpm for 1 minute. Immediately after spin coating, place the spin coated glass substrate in a nitrogen-purged glass container,
Irradiate 50mw / cm ² of UV light for 60 seconds, and
A transparent polymer thin film having a thickness of μm was formed on the substrate. A liquid crystal empty cell was prepared by laminating two substrates on which glass fiber spacers having a thickness of 8 μm were previously dispersed so that the transparent polymer thin films face each other. The following liquid crystal composition B was vacuum-injected and used for capacitance measurement.

For comparison, a transparent polymer thin film made of polyimide was prepared in the same manner as above except that polyimide (“PIX-5000” manufactured by Hitachi Chemical Co., Ltd.) was used instead of “IS-A”. A liquid crystal cell for measuring the capacitance was prepared.

The temperature was changed in the range of 10 to 60 ° C., and the capacitances of these two liquid crystal cells were measured. The electrostatic capacitance was measured with a sine wave of 1 kHz, and the electrostatic capacitance of homogeneous alignment was measured at a voltage of 0.4 V, which is lower than the threshold voltage of the liquid crystal material. The capacitance of homeotropic alignment was measured by applying a voltage of 10V.

The dielectric constant was calculated from the obtained capacitance, and the result is shown in FIG. The temperature change of the dielectric constant in a liquid crystal cell using a polyimide film is in agreement with the temperature change of the generally known dielectric constant, and the value of the dielectric constant ε // of the homeotropic alignment of the liquid crystal and the value of the dielectric constant ε ⊥ of the homogeneous alignment. Has been obtained. On the other hand, in the liquid crystal cell using the film made of isostearyl acrylate, the dielectric constant ε // of homeotropic alignment has the same tendency as the liquid crystal cell using the polyimide film, but the dielectric constant ε⊥ of homogeneous alignment is The liquid crystal cell using a film made of isostearyl acrylate shows a different trend from the liquid crystal cell using a homogeneously oriented polyimide film. For example, at a temperature of 60 ° C., the value of the permittivity ε⊥ in the homogeneous orientation is larger in the liquid crystal cell using the film made of isostearyl acrylate than in the liquid crystal cell using the polyimide film. When the temperature decreases, the permittivity ε⊥ of the homogeneous alignment of the liquid crystal cell using the film made of isostearyl acrylate gradually increases to 40 to 3
It rapidly increases between 0 ° C., and at 30 ° C. or lower, it completely matches the dielectric constant ε // of homeotropic orientation. This means that the alignment state of the liquid crystal molecules on the polymer interface changed from homogeneous alignment to homeotropic alignment due to the temperature change due to the action of the film made of isostearyl acrylate. The difference in the dielectric constant ε⊥ of the homogeneous alignment between the liquid crystal cell using a polyimide film and the liquid crystal cell using a film made of isostearyl acrylate at 60 ° C is that at the interface of the film made of isostearyl acrylate liquid crystal molecules at this temperature. It is considered that this is because the pretilt is induced. It can be understood from the change in the dielectric constant ε⊥ of the homogeneous alignment of the liquid crystal cell using the film made of isostearyl acrylate that the angle of the induced pretilt increases with decreasing temperature.

(Composition of liquid crystal composition B)

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<Examples 7 to 11> The pretilt-inducing isostearyl acrylate verified in Example 6 was used as a polymerizable compound constituting a transparent polymer substance in a liquid crystal device to adjust the temperature characteristics of the driving voltage.

<Example 7> (Liquid crystal material) Liquid crystal composition B used in Example 6 75.0% by weight (Polymerizable compound) "A-OCD" 12.1% by weight (Shin Nakamura Chemical's dimer Acrylate) "TO1338" 12.1 wt% (2-nonylundecyl acrylate manufactured by Toagosei Co., Ltd.) (Polymerization initiator) "Irgacure 651" (manufactured by Ciba-Geigy) 0.8 wt% Is sandwiched between two ITO electrode glass substrates coated with 11.0 μm glass fiber spacers, and while maintaining the temperature at which the light control layer forming material becomes an isotropic liquid state, 20 mW / cm ² of ultraviolet light is applied to 60
The polymerizable compound was cured by irradiation for 2 seconds to obtain a light-scattering type liquid crystal device having a light control layer of a thickness of 11.0 μm made of a liquid crystal material and a transparent polymer substance.

When the light control layer of the light-scattering liquid crystal device thus obtained was observed with an electron microscope, a transparent solid substance having a three-dimensional network could be confirmed.

<Example 8> (Liquid crystal material) Liquid crystal composition B used in Example 6 75.0% by weight (polymerizable compound) "A-OCD" 12.1% by weight (Shin Nakamura Chemical Co., Ltd. dimer Acrylate) "IS-A" 12.1 wt% (2- (1-methyl-3-dimethyl) -5-methyl-7-dimethyloctyl acrylate = isostearyl acrylate manufactured by Kyoei Chemical Co., Ltd.) (polymerization initiator) " Irgacure 651 ”(manufactured by Ciba-Geigy) 0.8% by weight of the light control layer forming material is sandwiched between two ITO electrode glass substrates coated with 11.0 μm glass fiber spacers to form a light control layer forming material. While maintaining the temperature at which it becomes an isotropic liquid, it is possible to apply 20 mW / cm ² of UV light to 60
The polymerizable compound was cured by irradiation for 2 seconds to obtain a light-scattering type liquid crystal device having a light control layer of a thickness of 11.0 μm made of a liquid crystal material and a transparent polymer substance.

When the light control layer of the light-scattering liquid crystal device thus obtained was observed with an electron microscope, a transparent solid substance having a three-dimensional network could be confirmed.

<Example 9> (Liquid crystal material) Liquid crystal composition B used in Example 6 75.0% by weight (Polymerizable compound) "A-OCD" 12.1% by weight (Shin Nakamura Chemical Co., Ltd. dimer Acrylate) "IS-A" 6.05% by weight (2- (1-methyl-3-dimethyl) -5-methyl-7-dimethyloctyl acrylate = isostearyl acrylate manufactured by Kyoei Chemical Co., Ltd.) "TO1338" 6.05 Weight control material (2-nonylundecyl acrylate manufactured by Toagosei Co., Ltd.) (Polymerization initiator) "Irgacure 651" (manufactured by Ciba Geigy) It is sandwiched between two ITO electrode glass substrates coated with spacers, and the purple light of 20 mW / cm ² is added while maintaining the temperature at which the light control layer forming material becomes an isotropic liquid state. Outside line 60
The polymerizable compound was cured by irradiation for 2 seconds to obtain a light-scattering type liquid crystal device having a light control layer of a thickness of 11.0 μm made of a liquid crystal material and a transparent polymer substance.

When the light control layer of the light-scattering type liquid crystal device thus obtained was observed with an electron microscope, a transparent solid substance having a three-dimensional network could be confirmed.

<Example 10> (Liquid crystal material) Liquid crystal composition B used in Example 6 75.0% by weight (Polymerizable compound) "A-OCD" 12.1% by weight (Shin Nakamura Chemical's dimer Acrylate) "IS-A" 2.42% by weight (2- (1-methyl-3-dimethyl) -5-methyl-7-dimethyloctyl acrylate = isostearyl acrylate manufactured by Kyoei Chemical Co., Ltd.) "TO1338" 9.68 Weight control material (2-nonylundecyl acrylate manufactured by Toagosei Co., Ltd.) (Polymerization initiator) "Irgacure 651" (manufactured by Ciba Geigy) It is sandwiched between two ITO electrode glass substrates coated with spacers, and the light control layer forming material is kept at a temperature of 20 mW / cm ² while maintaining a temperature at which it becomes an isotropic liquid state. 60 UV
The polymerizable compound was cured by irradiation for 2 seconds to obtain a light-scattering type liquid crystal device having a light control layer of a thickness of 11.0 μm made of a liquid crystal material and a transparent polymer substance.

When the light control layer of the light-scattering liquid crystal device thus obtained was observed with an electron microscope, a transparent solid substance having a three-dimensional network could be confirmed.

<Example 11> (Liquid crystal material) Liquid crystal composition B used in Example 6 75.0% by weight (Polymerizable compound) "A-OCD" 24.2% by weight (Dimer manufactured by Shin-Nakamura Chemical Co., Ltd. Acrylate) (Polymerization initiator) "Irgacure 651" (manufactured by Ciba-Geigy) 0.8% by weight of the light control layer forming material is applied to two ITO electrode glass substrates coated with 11.0 μm glass fiber spacers. When sandwiched, while maintaining the temperature at which the material for forming the light control layer becomes an isotropic liquid state, ultraviolet rays of 20 mW / cm ² are applied at 60
The polymerizable compound was cured by irradiation for 2 seconds to obtain a light-scattering type liquid crystal device having a light control layer of a thickness of 11.0 μm made of a liquid crystal material and a transparent polymer substance.

When the light control layer of the light-scattering liquid crystal device thus obtained was observed with an electron microscope, a three-dimensional mesh-like transparent solid substance could be confirmed.

Next, the results of measuring the voltage transmittance characteristics at 15 ° C., 25 ° C., 30 ° C. and 40 ° C. of the light scattering type liquid crystal devices obtained in Examples 7 to 11 are shown in Table 2 below.

[0103]

[Table 2]

<Example 12> (Liquid crystal material) Liquid crystal composition B used in Example 6 75.0% by weight (Polymerizable compound) "C9A" 11.9% by weight (2-manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. Ethyl-2-butylpropanediacrylate) "TO1338" 13.3% by weight (2-nonylundecyl acrylate manufactured by Toagosei Co., Ltd.) (Polymerization initiator) "Irgacure 651" (manufactured by Ciba Geigy) 0.8% by weight The dimming layer forming material consisting of is sandwiched between two ITO electrode glass substrates coated with a glass fiber spacer of 11.0 μm, and the dimming layer forming material is maintained at a temperature of 20 mW while maintaining a temperature in which it is in an isotropic liquid state. 60 / cm ² of ultraviolet rays
The polymerizable compound was cured by irradiation for 2 seconds to obtain a light-scattering type liquid crystal device having a light control layer of a thickness of 11.0 μm made of a liquid crystal material and a transparent polymer substance.

When the light control layer of the light-scattering liquid crystal device thus obtained was observed with an electron microscope, a transparent solid substance having a three-dimensional network could be confirmed.

Next, as a result of measuring the voltage transmittance characteristics of the light scattering type liquid crystal device thus obtained at 25 ° C., 30 ° C. and 40 ° C., the following characteristics were shown at each measurement temperature. 25 ° C T0 = 2.1%, T100 = 89.0%, V90
= 4.2Vrms 30 ° C T0 = 2.1%, T100 = 89.7%, V90
= 4.5Vrms 40 ° C T0 = 2.5%, T100 = 90.1%, V90
= 4.9Vrms

<Examples 13 to 16> Permittivity ε of vertical component
A light-scattering liquid crystal device was created using liquid crystal materials having different ⊥ (liquid crystal material) Any of the following liquid crystal compositions 1 to 75.0% by weight (polymerizable compound) "A-OCD" 7.2 weight % (Shin-Nakamura Chemical Co., Ltd. dimer acrylate) “IS-A” 17.0% by weight (Kyoei Chemical Co., Ltd. 2- (1-methyl-3-dimethyl) -5-methyl-7-dimethyloctyl acrylate = iso Stearyl acrylate) (Polymerization initiator) "Irgacure 651" (manufactured by Ciba-Geigy) 0.8% by weight of the light control layer forming material is applied to two ITO electrode glass substrates coated with 11.0 μm glass fiber spacers. It is sandwiched between the two, and while maintaining the temperature at which the light control layer forming material is in an isotropic liquid state, 6 m of ultraviolet light of 20 mW / cm2
The polymerizable compound was cured by irradiation for 0 seconds to obtain a light-scattering type liquid crystal device having a light control layer made of a liquid crystal material and a transparent polymer substance and having a thickness of 11.0 μm.

When the light control layer of the light-scattering liquid crystal device thus obtained was observed with an electron microscope, a transparent solid substance having a three-dimensional network could be confirmed.

(Composition of liquid crystal composition 1)

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(Composition of liquid crystal composition 2)

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(Composition of liquid crystal composition 3)

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(Composition of liquid crystal composition 4)

[Chemical 6]

Physical Properties of Liquid Crystal Materials 1 to 4 Used and Example 1
Table 3 below shows the relationship between the minimum values of the driving voltage of the liquid crystal devices obtained in 3 to 16.

[0114]

[Table 3]

As described above, when a light-scattering liquid crystal device is manufactured using a liquid crystal material having a small ε⊥, the minimum value of the driving voltage can be reduced.

Example 18 The liquid crystal material 3 was used to adjust the temperature characteristics of the driving voltage with the following composition. (Liquid crystal material) Liquid crystal material 3 75.0% by weight (ε⊥: 3.44; ε //: 11.77; Vth: 2.05; Δn: 0.24) (Polymerizable compound) “A-OCD” 12.1% by weight (Shin Nakamura Chemical company's dimer acrylate) "IS-A" 12.1% by weight (Kyoei Chemical company's 2- (1-methyl-3-dimethyl) -5-methyl-7-dimethyloctyl acrylate = isostearyl acrylate) ( Polymerization initiator) “Irgacure 651” (manufactured by Ciba-Geigy) 0.8% by weight of the light control layer forming material is sandwiched between two ITO electrode glass substrates coated with 11.0 μm glass fiber spacers to adjust the light intensity. While maintaining the temperature at which the material for forming the light layer becomes an isotropic liquid state, ultraviolet rays of 20 mW / cm ²
The polymerizable compound was cured by irradiation for 2 seconds to obtain a light-scattering type liquid crystal device having a light control layer of a thickness of 11.0 μm made of a liquid crystal material and a transparent polymer substance.

When the light control layer of the light-scattering type liquid crystal device thus obtained was observed with an electron microscope, a transparent solid substance having a three-dimensional network could be confirmed.

Next, as a result of measuring the voltage transmittance characteristics of the light-scattering type liquid crystal device thus obtained at 25 ° C., 30 ° C. and 40 ° C., the following characteristics were shown at each measurement temperature. 25 ° C T0 = 1.4%, T100 = 89.0%, V90
= 4.8Vrms 30 ° C T0 = 1.5%, T100 = 89.2%, V90
= 4.8Vrms 40 ° C T0 = 1.7%, T100 = 90.1%, V90
= 4.6 Vrms

[0119]

The light-scattering liquid crystal device obtained by the manufacturing method of the present invention does not require a polarizing plate and has a bright display screen, and has a large area and a thin film type. Further, it is a light-scattering type liquid crystal device in which the temperature dependence of the driving voltage is small and the change in display characteristics due to the operating temperature is small.

[Brief description of drawings]

FIG. 1 is a chart showing a change in dielectric constant with a change in temperature in a liquid crystal cell for measuring capacitance used in Example 6.

[Explanation of symbols]

▲-▲ Dielectric constant of homogeneous alignment when using a liquid crystal cell with an isostearyl acrylate film (ε⊥) ◆-◆ Dielectric constant of homeotropic alignment when using a liquid crystal cell with an isostearyl acrylate film (ε /
/) ■ − ■ Dielectric constant of homogeneous alignment (ε⊥) when using liquid crystal cell with polyimide film ● − ● Dielectric constant of homeotropic alignment (ε //) when using liquid crystal cell with polyimide film

Claims (9)

[Claims] 1. At least one transparent substrate having an electrode layer, and a dimming layer supported between these substrates, wherein the dimming layer comprises a liquid crystal material and a transparent polymer substance. In a light-scattering liquid crystal device containing: (1) the transparent polymer substance forms a transparent polymer substance that constitutes a dimming layer of the light-scattering liquid crystal device in which the driving voltage decreases with increasing temperature. A polymerizable composition containing a polymerizable compound and (2) a polymerizable compound that forms a transparent polymer substance that constitutes a light control layer of a light-scattering liquid crystal device in which a driving voltage increases with an increase in temperature. A light-scattering type liquid crystal device characterized by being a transparent polymer substance. 2. A polymerizable compound forming a transparent polymer substance constituting a light control layer of a light scattering liquid crystal device in which a driving voltage increases with an increase in temperature is an alkyl acrylate, and an alkyl group in a molecule. 2. The light-scattering liquid crystal device according to claim 1, which is a compound selected from the group consisting of alkyl acrylates having the longest hydrocarbon chain of 7 to 12 carbon atoms. 3. A polymerizable compound forming a transparent polymer substance constituting a light control layer of a light-scattering type liquid crystal device in which a driving voltage increases with an increase in temperature is 2- (3-methylbutyl) -7- Methyloctyl acrylate, 2- (1-methylbutyl) -5-methyloctyl acrylate and 2
The light-scattering liquid crystal device according to claim 1, which is a compound selected from the group consisting of-(1-methyl-3-dimethyl) -5-methyl-7-dimethyloctyl acrylate. 4. A polymerizable compound forming a transparent polymer substance constituting a light control layer of a light-scattering type liquid crystal device in which a driving voltage increases with an increase in temperature is neopentyl glycol diacrylate, 2-ethyl-2. The light-scattering liquid crystal device according to claim 1, which contains a compound selected from the group consisting of -butyl-propanediol diacrylate and a compound selected from the group according to claim 2. 5. A polymerizable compound forming a transparent polymer substance constituting a light control layer of a light scattering type liquid crystal device in which a driving voltage decreases with an increase in temperature is 2-octyldecyl acrylate or 2-heptylnonyl. Acrylate, 2-nonyl undecyl acrylate, 2-decyl dodecyl acrylate, and (1,2-hydroxyoctyl-3-octyl-4-hexyl) cyclohexane and 9-nonyl-1.
The light-scattering liquid crystal device according to claim 1, which is a compound selected from the group consisting of diacrylate esters of a mixture of 0-octylnonadecanediol. 6. A polymerizable compound that forms a transparent polymer substance that constitutes a dimming layer of a light-scattering liquid crystal device in which a driving voltage rises with an increase in temperature is a compound that induces pretilt with respect to liquid crystal molecules. The light-scattering liquid crystal device according to claim 1. 7. A polymerizable compound forming a transparent polymer substance forming a dimming layer of a light-scattering type liquid crystal device in which a driving voltage increases with an increase in temperature causes a pretilt to liquid crystal molecules, and The light-scattering liquid crystal device according to claim 1, further comprising a compound that increases the pretilt angle from 5 degrees or more to 40 degrees or less as the temperature falls at 0 ° C to 70 ° C. 8. The liquid crystal material contains a liquid crystal compound having a fluorine substituent, and the dielectric constant (ε⊥) of the vertical component is 5.5 or less. 5, 6
Alternatively, the light-scattering liquid crystal device according to item 7. 9. A dimming layer formation comprising a polymerizable composition containing (A) a liquid crystal material and (B) a polymerizable compound and a polymerization initiator between at least one transparent substrate having an electrode layer. By interposing a material and irradiating with ultraviolet rays,
In the method for producing a light-scattering liquid crystal device, in which a dimming layer containing a liquid crystal material and a transparent solid substance is formed between two substrates by polymerizing a polymerizable compound, the polymerizable composition comprises (1) A polymerizable compound that forms a transparent polymer substance that constitutes a light control layer of a light-scattering liquid crystal device in which the driving voltage decreases with an increase in temperature, and (2) a light scattering in which the driving voltage increases with an increase in temperature The method for producing a light-scattering liquid crystal device, which comprises using a polymerizable composition containing a polymerizable compound forming a transparent polymer substance constituting a light control layer of the liquid crystal device.