JP2853249B2 - Liquid crystal device and method of manufacturing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a liquid crystal device having a large area. The present invention relates to a liquid crystal device for blocking and releasing a visual field, and restricting and blocking transmission of light or illumination light. , Which can be electrically or thermally controlled in transmission, is used as a screen for blocking the view in building windows or show windows, and as a curtain for lighting control, and has a simple dot matrix type electrode configuration for characters. It is used as a display device such as an advertising board, a guide board, a decorative display board, or the like by displaying an image or a figure and electrically switching the display with high-speed response.

<Conventional technology> Liquid crystal devices have traditionally used TN
Type and STN type are in practical use. Further, a device using a ferroelectric liquid crystal has been proposed. These require a polarizing plate and require an alignment treatment. On the other hand, without them, bright and good contrast,
As a method of manufacturing a large and inexpensive liquid crystal dehice, liquid crystal encapsulation disperses liquid crystal droplets in a polymer,
There is a method of forming the polymer into a film. Here, gelatin, gum arabic, polyvinyl alcohol, and the like have been proposed as encapsulating substances (Japanese Patent Application Publication No.
58-501631, USP4435047).

In the technique disclosed in the above specification, the liquid crystal molecules encapsulated in polyvinyl alcohol can be used in the presence of an electric field if the liquid crystal molecules have a positive dielectric anisotropy in a thin layer. There are arranged in the direction of the electric field, when the refractive index n _p of the refractive index n _o and the polymer of the liquid crystal are equal, express transparency. When an electric field is removed, the liquid crystal molecules are returned to the random sequence, the refractive index of the liquid crystal droplets is deviated from the n _o, the liquid crystal droplets scatter light at the boundary surface, since blocking the transmission of light,
The thin body becomes cloudy. Several techniques other than those described above for forming a thin film of a polymer in which liquid crystals encapsulated in this manner are dispersed and encapsulated are known.
No. 502128, liquid crystal dispersed in epoxy resin,
Japanese Patent Application Laid-Open No. 62-2231 discloses a liquid crystal dispersed in a special ultraviolet-curable polymer.

<Problems to be Solved by the Invention> In the conventional liquid crystal device as described above, since the liquid crystal droplets are dispersed in the polymer, when an electric field is applied, the electric field is applied to the liquid crystal droplets through the polymer. In order to change the arrangement of molecules, a high driving voltage is required, which has various drawbacks in practical use.

In addition, in order to achieve sufficient transparency when an electric field is applied, there is an annoyance that the refractive index of the liquid crystal and the refractive index of the polymer must be sufficiently selected so as to be close to each other.

Furthermore, in performing a large-scale display by multiplex driving by taking advantage of the characteristics of a large-area device, there is no threshold necessary to enable the display.
Its implementation is difficult.

These points are major obstacles in putting a large-area liquid crystal device into practical use, and are problems to be solved. The present inventors have intensively studied to solve these problems, and have come to find a liquid crystal device having a low voltage driving property, a high contrast property, and a clear threshold value for a large-sized display electronic device, and a manufacturing method thereof.

<Means for Solving the Problems> In order to solve the above problems, the present invention has two substrates having at least one electrode layer which are transparent and a dimming layer supported between the substrates. In a liquid crystal device in which a light layer forms a three-dimensional network structure of a transparent solid substance in a continuous layer of a liquid crystal material, when the network removes the liquid crystal material, the void area ratio in the cross section of the light control layer is 60 to In the 95% range,
It is characterized by the fact that the gap part whose pore diameter is 0.3 micron or more and 30% or less of the layer thickness of the light control layer (however, the thickness of the light control layer is 5 to 30 microns) occupies 80% or more of the total void area. And a liquid crystal device.

The present invention provides a liquid crystal device having a light modulating layer having a large void density and a uniform size of the voids.

That is, the present invention relates to a three-dimensional network structure, and has an unprecedentedly high contrast and low-voltage driving by increasing the density of the network pores and adjusting the size of the pore diameter of the network to a certain range. And a liquid crystal device showing a clear threshold value.

The network void density, that is, the void area ratio to the light control layer cross section when the liquid crystal material in the light control layer is removed
When the content is 60 to 95%, preferably 70 to 90%, the liquid crystal material can form a continuous phase over the entire surface. Therefore, the driving voltage of the liquid crystal device is several volts to 30 volts, which is extremely lower than the conventional one.

In addition, despite the high void density, it is possible to have a clear threshold value by uniformizing the distribution of the void diameter of the network from the length of the wavelength in the visible light region to a fine void diameter range of several microns, Further, since the network density is high, the interface between the liquid crystal material and the transparent solid substance is dramatically increased as compared with the conventional liquid crystal dispersion type. Therefore, scattering of light when no voltage is applied, that is, cloudiness and opacity can be greatly increased.

As such a pore diameter distribution, the area of the void portion in the light control layer cross section whose pore diameter falls within the range of 0.3% to 30% or less of the layer thickness in the light control layer is preferably 80% or more of the total void area ratio. Is more than 90%. However, the thickness of the light control layer is 5 to 30 microns.

In the prior art, when the thickness of the light control layer is 10 microns or less, the white turbidity is small and the contrast is not sufficient, but in the present invention, even when the light control layer is 10 microns or less in thickness, the light scattering property is large. A liquid crystal device having turbidity can be provided, and the driving voltage can be further reduced.

In the present invention, in measuring the pore diameter, the pore density, the pore size distribution, and the like of the network, the liquid crystal device of the present invention is frozen with liquid nitrogen to solidify the liquid crystal material, and the viscoelasticity of the network polymer is also measured. After the suppression, the device is broken in the normal direction of the device, the liquid crystal material is removed in vacuum, and the measurement is performed while observing the irregular fracture surface with a scanning electron microscope. Alternatively, one of the substrates may be separated, and the separated surface may be observed.

When the ratio of the pore diameter of the network becomes smaller than 0.3 micron, the light absorption in the visible light region is reduced, or the light scattering when no voltage is applied is reduced. In addition, the network voltage becomes too narrow, so that the movement voltage of the liquid crystal molecules is restricted, or the amount of the transparent solid material is increased, or the driving voltage is increased.
Further, when the ratio of the void diameter increases to 30% or more of the layer thickness of the light control layer (however, the thickness of the light control layer is 5 to 30 microns),
The "threshold" is not appropriate, probably because the interface between the liquid crystal and the transparent solid material becomes smaller, the light scattering property when no voltage is applied is reduced, the opacity is worsened, and the liquid crystal molecules become too mobile. It will be clear.

Since the liquid crystal device according to the present invention has a high ratio of the liquid crystal material in the light control layer and forms a continuous layer, the transparency when a voltage is applied is high.

Further, since the degree of light scattering is large, the thickness of the light control layer can be reduced to 10 μm or less, and therefore, there is an advantage that the transparency when voltage is applied can be further improved.

From such a point, the thickness of the light control layer of the liquid crystal device according to the present invention can be selected from the range of 5 to 30 microns, and preferably from 8 to 15 microns.

The substrate may be a rigid material, for example, glass, metal, or the like, or a flexible material, for example, a plastic film. And the substrate is 2
The sheets are obtained facing each other at an appropriate interval. Also,
At least one of them must be transparent so that the light control layer sandwiched between the two can be seen from the outside. However, complete transparency is not essential. If the liquid crystal device is used to act on light passing from one side of the device to the other, both substrates are provided with the appropriate transparency. Appropriate transparent and opaque electrodes may be disposed on the entire or partial surface of the substrate depending on the purpose.

However, in the case of a flexible material such as a plastic film, the manufacturing method of the present invention can be used by fixing to a rigid material, for example, glass, metal or the like.

A light control layer composed of a liquid crystal material and a transparent solid component is interposed between the two substrates. Note that, between the two substrates,
As in the known liquid crystal device, it is desirable to interpose a spacer for maintaining the interval.

As the spacer, for example, those for various liquid crystal cells such as mylar and alumina can be used, and a rod-type glass fiber is preferable.

The liquid crystal material need not be a single liquid crystal compound, but may be a mixture containing two or more liquid crystal compounds or a substance other than the liquid crystal compound. Any of those which are recognized as such may be used, and among them, those having the dielectric anisotropy are preferable. As the liquid crystal 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, a chiral compound, a dichroic dye, or the like may be appropriately contained.

The nematic liquid crystal has the dielectric anisotropy and has a dielectric anisotropy of Δ8 or more and a birefringence of Δn of 0.1 or more, preferably 10 or more. , Δn are nematic liquid crystals of 0.2 or more. Δn is preferably as large as possible to increase white turbidity, increase contrast, and enhance steepness.

Regarding the difference in the refractive index between the liquid crystal and the polymer, which is a problem in the liquid crystal device of the liquid crystal dispersion type, in the present invention, it is possible to combine a wide range of liquid crystals and polymers without having to worry too much because the liquid crystal component is large. Become. Such a liquid crystal material is a compounded composition composed of the compounds shown in Table 1, and has the properties of the liquid crystal material, that is, the phase transition temperature between the isotropic liquid and the liquid crystal, the melting point, the clay, Δn, Δε, and For the purpose of improving the solubility with the polymerizable composition or the like, it is appropriately selected and blended for use.

The ratio of the liquid crystal material in the light control layer is 60 to 95% by weight, preferably 70 to 90% by weight.

(Hereinafter,% means% by weight) The transparent solid substance having a three-dimensional network structure interposed in the continuous layer of the liquid crystal material is not limited to a solid substance, and may have flexibility, flexibility, and elasticity as long as it can meet the purpose.

As these transparent solid substances, high molecular polymers are suitable.

The method of manufacturing these liquid crystal devices can be performed as follows.

That is, a liquid crystal material, a polymerizable composition and, as optional components, a polymerization initiator, a chain transfer agent, a photosensitizer, and a dye are provided between two substrates having at least one of which may have an electrode layer having transparency. A liquid crystal material is formed as a continuous layer by supplying polymerization energy and polymerizing and curing the polymerizable composition with a light modulating layer constituent material including a cross-linking agent and other components interposed therebetween, and forming a three-dimensional network in the continuous layer. A method for manufacturing a liquid crystal device by depositing and forming a transparent solid material.

In order to interpose the dimming layer constituent material between two substrates, the dimming layer forming material may be injected between the substrates. However, an appropriate solution coater or a spin coater may be used on one of the substrates. It may be applied uniformly, and then the other substrate may be overlaid and pressed.

Also, after applying a light control layer constituting material to one substrate to a uniform thickness and forming a light control layer for polymerizing and curing the polymerizable composition,
A liquid crystal device manufacturing method in which the other substrate is bonded is also effective.

As the energy for polymerization, any energy can be used as long as the polymer forms an appropriate three-dimensional network, and examples thereof include radiation such as ultraviolet rays and electron beams, and heat.

Particularly, a polymerization method using ultraviolet irradiation is preferable. In the polymerization of a polymerizable composition in a liquid crystal material by ultraviolet irradiation, the light irradiation intensity and the irradiation amount also need to be at least a certain level, which depends on the reactivity of the polymerizable composition and the type and concentration of the polymerization initiator. The formation of a three-dimensional network and the uniformity of the size of the network can be achieved by selecting an appropriate light intensity. It is more preferable to uniformly irradiate the polymerizable composition interposed between the substrates as a light irradiating method more preferably by instantly intensely irradiating the polymerizable composition interposed between the substrates with a strong light, thereby making the mesh size uniform. It is effective in measuring. In other words, a uniform three-dimensional network polymer can be realized in the liquid crystal phase by irradiating in a pulsed manner with an appropriate light intensity, and the resulting liquid crystal device has a clear threshold and good steepness. Driving becomes possible.

Such an ultraviolet irradiation dose requires an irradiation intensity of 10 mJ / cm ² or more at a light intensity of at least 3 mW / cm ² or more. If it is less than this, polymerization is insufficient or a uniform network cannot be formed, which is unsuitable for time division driving. In order for the polymer to be formed to constitute a three-dimensional network of a uniform network, and to show a clear threshold value, it is preferable that the ultraviolet intensity be as strong as possible.
Generally, irradiation at 30 mW / cm ² or more is preferable for 5 to 10 seconds.

Regarding the polymerization temperature, it is preferable that the temperature is as low as possible in the isotropic liquid state.

When the polymerization temperature is high, the liquid crystal device has poor turbidity because the polymerization rate is too high or the degree of polymerization is not sufficiently high, and in some cases, the liquid crystal device becomes transparent even in a no-voltage state, and the driving voltage becomes high. It is not practical. Such a high temperature is approximately equal to or higher than the temperature of the phase transition point of the liquid crystal material.

Examples of the polymerizable composition include a polymer-forming monomer or oligomer and, if necessary, a polymerization initiator,
What is necessary is just to form a three-dimensional network in a continuous layer of a liquid crystal material.

Examples of such a polymer-forming monomer include, for example,
Styrene, chlorostyrene, α-methylstyrene, divinylbenzene: as a substituent, methyl, ethyl, propyl, butyl, amyl, 2-ethylhexyl, octyl, nonyl, dodecyl, hexadecyl, octadecyl,
Having a group such as cyclohexyl, benzyl, methoxyethyl, butoxyethyl, phenoxyethyl, allyl, methallyl, glycidyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-chloro-2-hydroxypropyl, dimethylaminoethyl, diethylaminoethyl, etc. Acrylates, methacrylates or fumarates; mono- (meta) such as ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-butylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, trimethylolpropane, glycerin and pentaerythritol ) Acrylate or poly (meth) acrylate; vinyl acetate, vinyl butyrate or vinyl benzoate, acrylonitrile, Ruvinyl ether, limonene, cyclohexene, diallyl phthalate, diallyl isophthalate, 2-, 3- or 4-vinylpyridine, acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-hydroxymethylacrylamide or N-hydroxyethylmethacrylamide and the like A di (meth) acrylate of a diol obtained by adding 2 mol or more of ethylene oxide or propylene oxide to 1 mol of neopentyl glycol,
Dimethyl or tri (meth) acrylate of triol obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of trimethylolpropane, and obtained by adding 2 mol or more of ethylene oxide or propylene oxide to 1 mol of bisphenol A. A reaction product of 1 mol of di (meth) acrylate or 2-hydroxyethyl (meth) acrylate of a diol with 1 mol of phenyl isocyanate or n-butyl isocyanate,
Poly (meth) acrylate of dipentaerythritol,
Tris- (hydroxyethyl) -isocyanuric acid poly (meth) acrylate, tris- (hydroxyethyl)
Poly (meth) acrylate of phosphoric acid; mono (meth) acrylate or di (meth) acrylate of di- (hydroxyethyl) -dicyclopentadiene; and the like.

Examples of the polymer-forming oligomer include (1) an epoxy (meth) acrylate obtained by esterifying bisphenol A type epoxy resin with (meth) acrylic acid and, in some cases, a long-chain fatty acid such as coconut oil fatty acid, or an epoxy (meth) acrylate thereof; Epoxy such as epoxy (meth) acrylate having a carboxyl group obtained by adding a dibasic acid anhydride, a tetrabasic acid dianhydride, and trimellitic anhydride to an epoxy (meth) acrylate having a long chain fatty acid and an epoxy (meth) acrylate having a hydroxyl group (Meth) acrylates and modified products thereof.

(2) British Patent No. 1,147,732 (JP-A-51-371)
No. 93 and JP-A-51-138797), a terminal isocyanate compound obtained by preliminarily reacting a diisocyanate compound with a polyol is further reacted with β.
-In the molecule obtained by reacting hydroxyalkyl acrylate and / or methacrylate
An addition polymerizable compound having at least two acryloyloxy and / or methacryloyloxy groups.

(3) A dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, or head anhydride described in JP-B-47-3262. A linear polyester compound having a large number of acryloyloxy and / or methacryloyloxy groups obtained by ring-opening polymerization of glycidyl acrylate and / or glycidyl methacrylate.

(4) Polyhydric alcohols having at least three esterifiable hydroxyl groups at adjacent carbon atoms as described in JP-B-47-23661, acrylic acid and / or methacrylic acid, and dicarboxylic acid And polymerizable esters produced by co-esterification with a dicarboxylic acid selected from the group consisting of anhydrides thereof.

(5) UK Patent 628,150, US Patent 3,02
0,255 specification and monthly magazine "Macro Moleculars"
Vol. 4, No. 5, pp. 630-632 (1971), polyacryl obtained by reacting melamine or benzoguanamine with formaldehyde, methyl alcohol, β-hydroxyalkyl acrylate (or methacrylate), or the like. (Or polymethacryl)
Modified triazine resin.

(6) An unsaturated polyester resin obtained by reacting acrylic acid or methacrylic acid with a glycidyl etherified product of a polyhydroxy compound as described in US Pat. No. 3,377,406.

(7) U.S. Pat. No. 3,455,801 and U.S. Pat.
General formula described in 3,455,802 specification (Where R represents a divalent saturated or unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, and R ′ represents 2 carbon atoms.
10 represents two saturated aliphatic hydrocarbon groups, R ″ represents a hydrogen atom or a methyl group, and n is an integer of 1 to 14.) An acryloyloxy group or a methacryloyloxy group is provided at both ends. Polyester compound having a group.

(8) U.S. Pat. No. 3,483,104 and U.S. Pat.
General formula described in 3,470,079 specification (Where A represents -O- represents -NH-, at least two of which are -NH- in one molecule, R represents a divalent saturated aliphatic or unsaturated aliphatic hydrocarbon group, R ′ represents a divalent saturated or unsaturated aliphatic or cyclic hydrocarbon; R ″ represents a hydrogen atom or an alkyl group;
It is assumed to be an integer of 14. ) Diacrylic modified (or dimethacrylic modified)
Polyamide compounds.

(9) General formula described in JP-B-48-37246 (Where X represents a hydrogen atom or an acyl group, R represents a divalent saturated or unsaturated aliphatic or cyclic hydrocarbon group, R ′ represents a divalent aliphatic hydrocarbon group, and R ² represents A represents a hydrogen atom or an alkyl group, A represents -O- or -NH-, and at least two of them represent -NH- in one molecule.
And n is an integer of 1 to 14. ) Diacrylic modified (or dimethacrylic modified)
Polyamide compounds.

(10) A saturated or unsaturated dibasic acid or an anhydride thereof as described in US Pat. No. 3,485,732, or a carboxyl group at both ends obtained by reacting them with a diol if necessary. A diacryl-modified (or dimethacryl-modified) polyester compound obtained by reacting a compound having the following formula with glycidyl acrylate or glycidyl methacrylate.

(11) General formula in the molecule as described in JP-B-48-12075 (Where X represents an acyl group or a urethane group;
Is H, CH ₃ , Cl or CN. A compound based on a (meth) acrylic copolymer having an unsaturated acid ester bond in a side chain having a repeating unit represented by the following formula:

And the like.

As the polymerization initiator, for example, 2-hydroxy-2-
Methyl-1-phenylpropan-1-one (“Darocur 1173” manufactured by Merck), 1-hydroxyclohexyl phenyl ketone (“Irgacure 18” manufactured by Ciba-Geigy)
4 "), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one (" Darocure 1116 "manufactured by Merck), benzyldimethylketal (" Irgacure 651 "manufactured by Ciba-Geigy), 2-Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1 ("Irgacure" manufactured by Ciba-Geigy)
907)), a mixture of 2,4-diethylthioxanthone ("Kayacure DETX" manufactured by Nippon Kayaku Co., Ltd.) and ethyl p-dimethylaminobenzoate ("Cycure-EPA" manufactured by Nippon Kayaku Co., Ltd.), isopropylthioxanthone (word pre A mixture of “Kantopure ITX” manufactured by Kinsopp Co., Ltd.) and ethyl p-dimethylaminobenzoate, and the like, but a liquid 2-hydroxy-2-methyl-1-phenylpropane-
1-one is particularly preferable in terms of compatibility with the liquid crystal material, the polymer-forming monomer or the oligomer.

<Examples> Hereinafter, examples of the present invention will be described, and the present invention will be described more specifically. However, the present invention is not limited to these examples.

Hereinafter, in Examples,% indicates% by weight, and each of the evaluation characteristics means the following symbols and contents.

T ₀ = turbidity; light transmittance (%) when applied voltage is 0 T ₁₀₀ = transparency; light transmittance (%) when light transmittance hardly increases as applied voltage is increased V ₁₀ = Threshold: applied voltage (V _rms ) at which light transmittance becomes 10% when T ₀ is 0% and T ₁₀₀ is 100% V ₉₀ = saturation voltage; V
_rms ) CR = Contrast = T ₁₀₀ / T ₀ CR _m = [Light transmittance at the time of selected waveform] / when applying a time-sharing drive voltage waveform of pulse width 10msec, 1/3 bias method, 1/2 duty [Light transmittance when non-selective waveform is applied] ・ Void area ratio = S _s (%): The ratio of the area occupied by the void portion in the cross-sectional photograph by SEM (scanning electron microscope), and the diameter of the void seen in the photograph is the diameter. It is obtained by calculating the area of each mesh assuming a circle.

・ Area distribution ratio of void diameter = S _n (%): Same as above. Ratio of void area occupied by constant void diameter to total void area ・ Void diameter = γ (micron) -Thickness of light control layer: d (micron) Example 1 80% of the composition (A) described below as a liquid crystal material, and caprolactone-modified hydroxypivalate neopentyl glycol diacrylate as a polymerizable oligomer (KAYARAD- manufactured by Nippon Kayaku Co., Ltd.) HX-620) 19.6%, 2-hydroxy-2-methyl-1-phenylpropane- as a polymerization initiator
1-one 0.4% mixed solution of the dimming layer constituent material was applied to 11 micron glass fiber spacer coated IT
O glass substrate is sandwiched, and the whole substrate is at a temperature 2 ° C. higher than the liquid crystal phase of the mixed solution and the phase transition point of the isotropic liquid, ie, 40 ° C.
The liquid mixture was irradiated with ultraviolet light of 35 mW / cm ² for 6 seconds while the mixed solution was in an isotropic liquid state to obtain a liquid crystal device having a light control layer thickness d = 11.2 microns.

Liquid crystal composition (A) composition Transition temperature 68.5 ℃ (N-1) < -25 ℃ (C-N) refraction index _{n e = 1.787 n o = 1.533} Δn = 0.254 threshold voltage 1.15V (V _th) viscosity of 20 ℃ 59c.p. Dielectric Anisotropy Δε = 26.9 In the obtained liquid crystal device, S _s = 78%, = 1.3 μm, and the ratio S _u occupying 0.8 to 2.4 μm, S _u = 93%.

When the relationship between the applied voltage and the light transmittance of this liquid crystal device is measured, T ₀ = 3.1%, T ₁₀₀ = 85.4%, CR = 27.5, V ₁₀ = 8.
2V _rms and V ₉₀ = 23.5V _rms .

FIGS. 1 and 2 show optical response waveforms when a time-division driving applied voltage waveform is applied to the device using this liquid crystal device. A voltage waveform of pulse width 10 msec., 1/3 device method, 1/2 duty is applied to the liquid crystal device, and the optical response waveform is observed. When the selection waveform of (1) is applied, the transmittance increases to nearly 50%, and (2)
When the non-selection waveform is applied, the transmittance does not largely change, and the contrast ratio at the time-division driving shows a high value of 1:18, which indicates that the time-division driving can be performed. The response speed is as fast as 1 to 2 msec for the rise time and 3 to 5 msec for the fall time, and is a value that can further increase the duty ratio. As described above, the present invention provides an excellent liquid crystal device capable of time-division driving, which has not been achieved by the prior art droplet dispersion type liquid crystal device.

Comparative Example 1 The liquid crystal composition (A) was 55%, and the polymerizable oligomer was 44.2%.
%, The polymerization initiator was 0.8%, and the polymerization temperature was 10 ° C., and the procedure was the same as in Example 1. The characteristics of the obtained device were as follows, and there was no white turbidity and low contrast and lacked practicality.

_{T 0 = 47.3, T 100 =} 81.8, CR = 1.73 the mesh state were those _{S s} = 24.3%, S _n is smaller 19.7% and the void ratio and gap spacing is γ is 0.3 or more in = 0.22 .

Example 2 82% of liquid crystal composition (A), 17.6% of polymerizable oligomer
A liquid crystal device was obtained in the same manner as in Example 1, except for the following.

 The characteristics of the obtained liquid crystal device were as follows.

Thickness of light control layer d = 11.0 microns, T ₀ = 3.2, T ₁₀₀ = 8
7.2, V ₁₀ = 5.3, V ₉₀ = 14.1, CR = 26.9 with clear thresholds and low drive voltage. The contrast when the time-division driving voltage waveform was applied was as high as CR _m = 18.8.

S _s = 78.4%, = 1.2 microns S _n = 95% with γ in the range of 0.3 to 1.9 microns Example 3 76.0% of liquid crystal composition (A), 23.5% of polymerizable oligomer
%, The polymerization initiator was 0.5%, and the polymerization temperature was 32 ° C., and the procedure was the same as in Example 1. The obtained device has a dimming layer thickness d = 11.2 microns, and the characteristics from voltage to light transmittance are as follows:
T ₀ = 4.9, T ₁₀₀ = 86.9, V ₁₀ = 9.0, V ₉₀ = 20.4, CR = 17.
8, CR _m = 13.5, and the mesh state by SEM is S _s = 76.
4, = 1.0, the ratio of γ occupying between 0.5 and 1.6 microns S _n =
92.4.

Example 4 The liquid crystal composition (A) was 72% and the polymerizable oligomer was 27.4.
%, The polymerization initiator was 0.6%, and the polymerization temperature was 26 ° C., and the procedure was the same as in Example 1. The resulting device has a dimming layer thickness d = 11.5 microns and the voltage-to-light transmittance characteristics are:
T ₀ = 7.3, T ₁₀₀ = 86.0, V ₁₀ = 11.4, V ₉₀ = 26.2, CR = 11.
8, CR _m = 8.8, which is good, S _s = 70.3%, = 0.8
2 microns γ was S _n = 96.4 between 0.3 and 1.2 microns.

Example 5 85% of liquid crystal composition (A) and 14.7 of polymerizable oligomer
%, Polymerization initiator to 0.3%, polymerization temperature to 43 ℃, 24
The same operation as in Example 1 was performed except that a micron spacer was used. The obtained device has a dimming layer thickness d = 24.5
Voltage-light transmittance characteristic in microns _{T 0 = 4.2, T 100 =} 81.
_{2, CR = 19.4, V 10} = 9.5, V 90 = 23.5, was good and CR _m = 6.5, the mesh state is γ by _{S s} = 81.5 = 1.9 0.6~3.2
It was S _n = 92 among microns.

Example 6 83.5% of composition (A) as a liquid crystal material, 16.42% of caprolactone-modified hydroxypivalate neopentyl glycol diacrylate (KAYARAD-HX-620 manufactured by Nippon Kayaku Co., Ltd.) as a polymerizable oligomer, and 2 as a polymerization initiator
-Hydroxy-2-methyl-1-phenylpropane-1
-The dimming layer constituent material, which is a mixed solution of 0.08% on, was coated with 11 micron glass fiber spacers on ITO.
8mW /
Irradiation with UV light of cm ² was performed for 20 seconds to obtain a liquid crystal device having a light control layer thickness d = 11.3 μm. The voltage to light transmittance characteristics of the obtained device are T ₀ = 6.3, T ₁₀₀ = 85.1, CR = 13.5, V ₁₀
= 2.7, V ₉₀ = 8.2, and the mesh state is S _s = 82.
6, gamma in = 2.1 was S _n = 92.8 between 0.3 to 3.3 microns.

<Effect of the Invention> The liquid crystal device according to the present invention can be of a large-area thin film type, and is 5 times smaller than a conventional liquid crystal dispersion type liquid crystal device.
Driving at a low voltage of up to 30 V is possible. Even at such a low voltage, since the contrast between transparent and opaque and opaque is high and the threshold value is clear, time-division driving with 1/3 duty is possible. Therefore, not only the conventional dimming control of this type of liquid crystal device, but also large-scale display of more advanced characters and graphics becomes extremely easy.

[Brief description of the drawings]

FIG. 1 shows a graph of time-applied voltage of the liquid crystal device according to the present invention, and FIG. 2 shows a graph of time-light transmittance corresponding to the applied voltage waveform of FIG.

Claims (5)

(57) [Claims] An at least one transparent electrode having an electrode layer.
A liquid crystal device comprising a plurality of substrates and a dimming layer supported between the substrates, the dimming layer comprising a three-dimensional network structure of a transparent solid substance in a continuous layer of a liquid crystal material; When the liquid crystal material is removed, the void area ratio in the cross section of the light control layer is in the range of 60 to 95%, and the void diameter is 0.3 μm or more and 30% or less of the layer thickness of the light control layer (however, The liquid crystal device is characterized in that the void portion of the liquid crystal device has a thickness of 5 to 30 microns or more with respect to the total void area. 2. The method according to claim 1, wherein the average gap distance of the network falls within a range of 0.3 μm or more and 30% or less of the thickness of the light control layer (the thickness of the light control layer is 5 to 30 μm). Liquid crystal device. 3. The liquid crystal device according to claim 1, wherein the liquid crystal material in the light control layer has a positive dielectric anisotropy. 4. A liquid crystal material comprising 60 to 95% by weight of a component of the light control layer.
The liquid crystal device according to claim 1, 2 or 3, wherein 5. The liquid crystal device according to claim 1, wherein the transparent solid substance is a polymer obtained by polymerizing a polymerizable composition.