JPH05249445A - Liquid crystal device - Google Patents

Abstract

PURPOSE:To form a light control layer by polymerizing the photopolymerizable compsn. of parts which are not irradiated with active rays by polymerizing the photopolymerizable compsn. contg. a photopolymerizable compsn. having an anaerobic curing property, thereby forming a transparent solid material. CONSTITUTION:A light control layer forming material consisting of a liquid crystal material, the photopolymerizable compsn. having the anaerobic curing property, a photopolymn. initiator and a chain transfer agent, photosensitizer, etc., as arbitrary components is interposed between two sheets of substrates having electrode layers and is irradiated with the active rays. The photopolymerizable compsn. having the anaerobic curing property to be used in this embodiment is stable and does not cure, insofar as the compsn. is in contact with a proper quantity of oxygen, such as oxygen partial pressure in the atm. but has the nature to start curing in a relatively short period of time when the contact with the oxygen is interrupted. After the photopolymerizable compsn. is polymerized and cured, the compsn. is rested for a prescribed period of time as it is and the parts which are prevented from being irradiated with the active rays by the wiring board, driving elements, etc., on the substrates and are insufficiently polymerized are completely polymerized by the anaerobic curing. As a result, the light control layer consisting of the liquid crystal material and the transparent solid material is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device capable of forming a large area and a method of manufacturing the same, and more specifically, blocking and opening a field of view and limiting transmission of light or illumination light.
It is possible to electrically control blocking and transmission, and a screen for blocking the field of view in a building window or show window,
It is used as a curtain for daylighting control, displays characters and figures, and electrically switches the display with high-speed responsiveness, so that it can be used as a high-information display for displays such as OA equipment, advertising boards, and guidance. Board,
The present invention relates to a liquid crystal device used as a display device such as a decorative display board.

[0002]

2. Description of the Related Art In order to enable low-voltage driving characteristics, high contrast, and time-division driving, which are important characteristics required for practical use of liquid crystal devices, JP-A-1-198725 discloses continuous liquid crystal materials. A liquid crystal device having a light control layer formed by forming a layer and forming a three-dimensional network polymer substance in the continuous layer is disclosed.

In such a liquid crystal device, a light control layer forming material containing a liquid crystal material, a photopolymerizable composition and a photopolymerization initiator is interposed between two transparent substrates having electrode layers,
By irradiating an actinic ray and polymerizing the said polymerizable composition, the light control layer which consisted of the above-mentioned liquid crystal material and transparent solid substance was formed.

[0004]

However, unlike the conventional liquid crystal device for dimming using such two transparent substrates, a display for OA equipment such as a computer,
In LCD devices for displaying advanced characters such as projection and viewfinder, and graphics,
Since the substrate is complicated and finely patterned, the substrate is not always transparent. In particular, many substrates on which wirings, driving elements, a black matrix, etc. are formed have an opaque portion.

When a liquid crystal device as described above is produced using a substrate having such an opaque portion, even if an actinic ray is applied to the substrate in which the light control layer forming material is interposed,
Since the opaque portion does not transmit actinic rays, the polymerizable composition in the light control layer forming material interposed in this portion cannot be polymerized or the polymerization is insufficient.

Further, the liquid crystal device produced by such a polymerization method has problems in terms of reliability and durability of the liquid crystal device due to changes in characteristics over time. The problem to be solved by the present invention is to form a uniform dimming layer by sufficiently polymerizing the photopolymerizable composition in a portion where the actinic ray is not irradiated by the wiring on the substrate, the driving element, the black matrix, etc. It is an object of the present invention to provide a method for manufacturing a liquid crystal device which is reliable and durable without change over time.

[0007]

The present inventors have arrived at the present invention as a result of extensive 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 is transparent, and a dimming layer supported between the substrates. A liquid crystal device containing a liquid crystal material and a transparent solid substance, wherein the transparent solid substance is a transparent solid substance formed by polymerizing a polymerizable composition containing a polymerizable composition having anaerobic curability. A characteristic liquid crystal device is provided.

The polymerizable composition having anaerobic curability used in the present invention is stable and does not cure as long as it is in contact with an appropriate amount of oxygen such as oxygen partial pressure in the atmosphere, but it does not contact with oxygen. A polymerizable composition having the property of starting to cure in a relatively short time when cut off.

When using a substrate having an opaque portion due to wiring, a driving device, a black matrix, etc., which has been a problem in the conventional method of polymerizing a polymerizable composition by irradiating with an actinic ray, the opaque portion is used. The polymerization of the light control layer forming material intervening in could not be performed, or was insufficient, but when using a polymerizable composition having anaerobic curability as in the present invention, after irradiation with actinic rays, Even if the polymerization is not performed or the polymerization is insufficient, the inside of the substrate is in an environment where the contact with oxygen is cut off, so that the polymerization can be completely progressed.

As a result, it is possible to obtain a liquid crystal device having high reliability and durability without any change in characteristics over time. The anaerobic curable polymerizable composition used in the present invention contains the following (a) to (c).

(A) Polymer-forming monomer or oligomer (b) Anaerobic curable polymerization initiator (c) Anaerobic curable polymerization accelerator Each component will be specifically described below.

Examples of the polymer-forming monomer that forms the transparent solid substance (a) include ethylene glycol,
Polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-butylene glycol, tetramethylene glycol, hexamethylene glycol,
Mono (meth) acrylates or poly (meth) acrylates such as neopentyl glycol, trimethylolpropane, glycerin and pentaerythritol; Diols of diols obtained by adding 2 moles or more of ethylene oxide or propylene oxide to 1 mole of neopentyl glycol. (Meth) acrylate; trimethylolpropane 1
Di- or tri (meth) acrylate of triol obtained by adding 3 mol or more of ethylene oxide or propylene oxide to mol; diol di (obtained by adding 2 mol or more of ethylene oxide or propylene oxide to 1 mol of bisphenol A (Meth) acrylate; reaction product of 1 mol of 2-hydroxyethyl (meth) acrylate and 1 mol of phenyl isocyanate or n-butyl isocyanate; poly (meth) acrylate of dipentaerythritol; pivalate neopentyl glycol diacrylate ; Caprolactone-modified hydroxypivalate neopentylglyco-
Ludia acrylate; linear aliphatic diacrylate; polyolefin modified neopentyl glycol diacrylate and the like.

Examples of the oligomer include epoxy (meth) acrylate, polyester (meth) acrylate, polyurethane (meth) acrylate, polyether (meth) acrylate and the like.

As the anaerobic curable polymerization initiator (b),
Mention may be made of cumene hydroperoxide or hydroperoxide derivatives such as t-butyl hydroperoxide. The amount of the anaerobic curable polymerization initiator used in the polymerizable composition is preferably 0.05 to 5% by weight, and 0.1 to 5% by weight.
A range of 3% by weight is particularly preferred.

As the anaerobic curable polymerization accelerator (c),
Dibenzenesulfonamide, tertiary amine, 1,2,3
4-tetrahydroquinoline etc. are mentioned. The amount of the anaerobic curable polymerization accelerator used in the polymerizable composition is preferably in the range of 0.1 to 10% by weight, particularly preferably in the range of 0.5 to 5% by weight.

By adding a photopolymerization initiator to these anaerobic curable polymerizable compositions, a photocurable polymerizable composition having anaerobic curability can be obtained. Such a polymerizable composition is Particularly preferred as the one used in the present invention.

The photopolymerization initiator is, for example, 2-hydroxy-2-methyl-
1-phenylpropan-1-one (“Darocur 1173” manufactured by Merck), 1-hydroxycyclohexylphenylketone (“Irgacure 18 manufactured by Ciba Geigy”)
4 "), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one (" Darocur 1116 "manufactured by Merck), benzyl dimethyl ketal (" Irgacure 651 "manufactured by Ciba-Geigy), 2-
Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1 (“Irgacure 907” manufactured by Ciba-Geigy) and 2,4-diethylthioxanthone (“Kayacure DEXT” manufactured by Nippon Kayaku Co., Ltd.) Ethyl p-dimethylaminobenzoate ("Kayakyu E" manufactured by Nippon Kayaku Co., Ltd.
PA "), a mixture of isopropylthioxanthone (manufactured by Ward Prekinsop Co.) and ethyl p-dimethylaminobenzoate, and the like.

As a polymerization initiator using visible light, 39
Any compound having absorption in the visible light region of 0 to 800 nm may be used, and examples thereof include dicarbonyl compounds such as camphorquinone, acylphosphine oxide compounds such as 2,4,6-trimethylbenzoylphenylphosphine oxide, and 2-
A thioxanthone compound such as chlorthioxanthone can be used, and the polymerizability can be improved by using a sensitizer such as an amine in combination. In particular,
It is desirable to use a sensitizer of camphorquinone and an amine together.

The proportion of the photopolymerization initiator used is preferably in the range of 0.1 to 5.0% by weight of the polymerizable composition. Further, as commercially available products of the polymerizable composition having anaerobic curability, “3062”, “3062B” and “3062” manufactured by Three Bond Co., Ltd.
C], “3062D],“ 3062E ”,“ 3062
F], "BU-130U" manufactured by Toagosei Kagaku Co., Ltd., "BU
"-230U", "BU-510U", etc. are mentioned.

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 separated by an appropriate distance, and the whole or a part of the dimming layer composed of a liquid crystal layer and a layer having a transparent solid substance sandwiched between the two substrates from the outside world. It has to be visual.
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, the two substrates are both provided with suitable transparency. However, this substrate is transparent depending on the purpose,
An appropriate opaque electrode or wiring, a driving element such as a thin film transistor, or an opaque portion such as a black matrix may be formed entirely or partially. However, in the case of a flexible material such as plastic, a rigid material,
For example, it can be used for the liquid crystal device of the present invention after being fixed to glass, metal or the like.

Further, a spacer for holding a space can be usually interposed between the two substrates, as in the well-known liquid crystal device. As the spacer, for example, those for various liquid crystal cells such as mylar, alumina, rod-type glass fiber, glass beads, and polymer beads 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. What is normally recognized as a liquid crystal material in this technical field may be used, and one having a positive dielectric anisotropy is preferable. The liquid crystal used is preferably a nematic liquid crystal, a smectic liquid crystal or a cholesteric liquid crystal, 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 phase transition between the isotropic liquid and the liquid crystal. Temperature, melting point, viscosity, refractive index anisotropy (Δ
n), dielectric anisotropy (Δε), solubility with a polymerizable composition and the like can be appropriately selected and blended for use.

Examples of the liquid crystal material 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'-substituted phenyl ester, 4- (4-substituted cyclohexyl) benzoic acid 4'-substituted 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)
A 5-substituted pyrimidine etc. can be mentioned.

The content of the liquid crystal material in the light control layer forming material containing the liquid crystal material according to the present invention, the anaerobic curable polymerizable composition and the photopolymerization initiator is preferably in the range of 70 to 95% by weight. , 75 to 90% by weight is particularly preferable.

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

A liquid crystal material is preferably filled in the three-dimensional network portion of the transparent solid substance, and the liquid crystal material preferably forms a continuous layer. It is essential for forming the boundary surface and expressing light scattering.

The liquid crystal device of the present invention can be manufactured as follows. That is, a liquid crystal material, an anaerobic curable polymerizable composition, between two substrates having an electrode layer,
A photopolymerization initiator and, as an optional component, a photochromic layer-forming material consisting of a chain transfer agent, a photosensitizer, a dye, a crosslinking agent, and the like is interposed, and the active composition is irradiated to polymerize the polymerizable composition. 15 minutes to 1 after curing
A liquid crystal device having a dimming layer composed of a liquid crystal material and a transparent solid substance is obtained by completely polymerizing a poorly polymerized portion such as a portion not irradiated with an actinic ray by anaerobic curing by leaving it for 2 hours. It can be manufactured.

By irradiating with actinic rays and then appropriately heating, polymerization under anaerobic conditions can be promoted and the time required for forming the light control layer can be shortened. To interpose the light control layer forming material between the two substrates,
This light control layer forming material may be injected between the substrates, but it is applied uniformly on one substrate by using an appropriate solution coating machine or spin coater, and then the other substrate is overlaid and pressure-bonded. Is also good.

In the method of manufacturing a liquid crystal device of the present invention, it is necessary to keep the light control layer forming material interposed between the substrates in an isotropic liquid state when irradiating with actinic rays so that the transparent solid substance can be made uniform. It is preferable for forming a simple three-dimensional network structure.

In order to polymerize the photopolymerizable composition in the liquid crystal material, light irradiation intensity and irradiation amount of a certain intensity or more are required, which is the reactivity of the photopolymerizable composition and the photopolymerization initiator. The three-dimensional network structure can be formed and the size of the network can be made uniform by selecting an appropriate light intensity. Since it has a value voltage and steepness, time-division driving becomes possible.

Any actinic ray may be used as long as it forms a transparent solid substance having a uniform network structure. Examples of the actinic ray include radiation such as ultraviolet rays, visible rays and electron beams, and ultraviolet rays are particularly preferable.

The thickness of the light control layer of the liquid crystal device obtained by the present invention is preferably in the range of 5 to 50 μm, particularly preferably in the range of 8 to 25 μm.

[0036]

EXAMPLES The present invention will be described in more detail below by showing Examples of the present invention. However, the invention is not limited to these examples.

In the following examples, "%" represents "% by weight", and each of the evaluation characteristics means the following symbols and contents. T ₀ : White turbidity; Light transmittance (%) when applied voltage is 0 T ₁₀₀ : Transparency; Light transmittance (%) when the applied voltage hardly increases with increasing applied voltage V ₁₀ : Threshold: _Applied voltage (V _rms ) V ₉₀ at which light transmittance is 10% when T ₀ is 0% and T ₁₀₀ is 100%: Saturation voltage; Same as above, applied voltage at which light transmittance is 90% ( V _rms ) CR: Contrast = T ₁₀₀ / T ₀ Resistance value: Measurement by AC wave method (voltage 1.1 V _rms )

(Example 1) As a liquid crystal material, "PN-0" was used.
08 "(manufactured by Rodick) 80.0%, as a polymerizable monomer," HX-620 "(manufactured by Nippon Kayaku Co. caprolactone modified hydroxypivalate neopentyl glycol diacrylate) 12.7%," 3062D "
A dimming layer forming material consisting of 6.8% (manufactured by ThreeBond Co., Ltd.) and 0.4% of “IRGACURE 651” (benzyl dimethyl ketal manufactured by Ciba-Geigy) as a photopolymerization initiator was used. While injecting into an empty cell with a substrate spacing of 11 microns consisting of two glass substrates with ITO electrodes (aperture ratio of 50%) that have been provided with stripe lines of micron and transparent line width of 100 microns, keeping the whole substrate at 36.2 ° C. ,
Irradiate with ultraviolet light of 50 mW / cm ² intensity for 30 seconds, and
The liquid crystal device was left at room temperature for 2 hours to obtain a liquid crystal device in which the transparent portion of the substrate was uniformly clouded.

When the light control layer of the obtained liquid crystal device was observed with an electron microscope, a three-dimensional mesh-like transparent solid substance could be confirmed. When the relationship between the applied voltage and the light transmittance of the white turbid portion of the obtained liquid crystal device was measured, T ₀ = 5.1
%, T ₁₀₀ = 89.8%, CR = 17.6, V ₁₀ = 5.7V _rms , V
₉₀ = 14.1 V _rms , and the resistance value was 6.2 × 10 ⁹ Ω · cm.

[0040] was measured this a liquid crystal device "Sunshine long-life weather meter" of (Suga Test Instruments Co., Ltd. weather resistance testing machine) at an applied voltage after irradiation for 500 hours and the light transmittance relationship, T ₀ = 5.2%, T ₁₀₀ = 89.8
%, CR = 17.3, V ₁₀ = 5.6 V _rms , V ₉₀ = 14.0 V _rms , and the resistance value was 6.0 × 10 ⁹ Ω · cm, showing almost no change compared to before the test.

(Comparative Example) As a liquid crystal material, "PN-00" was used.
8 "(manufactured by Rodick) 80.0%, as a polymerizable monomer," HX-620 "13.72%, lauryl acrylate (manufactured by Tokyo Kasei) 5.88%, and as a polymerization initiator," Irgacure 651 "0 A light control layer forming material consisting of 0.4% was injected into an empty cell similar to that used in Example 1, and the whole substrate was kept at 31.5 ° C. and irradiated with ultraviolet rays having an intensity of 50 mW / cm ² for 30 seconds. Then, a liquid crystal device in which the transparent portion of the substrate was uniformly clouded was obtained.

When the relationship between the applied voltage and the light transmittance of the transparent portion of this liquid crystal device was measured, T ₀ = 6.7%, T ₁₀₀
= 89.8%, CR = 13.4, V 10 = 4.1V rms, V 90 = 8.2V
_The resistance value was 2.0 × 10 ⁹ Ω · cm.

A weather resistance test was conducted on this liquid crystal device in the same manner as in Example 1, and the relationship between the applied voltage and the light transmittance was measured. T ₀ = 8.9%, T ₁₀₀ = 89.9%, CR = 10.
1, V ₁₀ = 3.7 V _rms , V ₉₀ = 7.3 V _rms , and the resistance value was 6.8 × 10 ⁸ Ω · cm.

As described above, it is clear that the liquid crystal device of the comparative example in which the photopolymerizable composition having the anaerobic curability is not used has a characteristic change with time.

[0045]

INDUSTRIAL APPLICABILITY The liquid crystal device of the present invention can polymerize a portion of the polymerizable composition which is not irradiated with an actinic ray by the wiring on the substrate, the driving element, the black matrix, etc. by anaerobic curing, so that the characteristic changes with time. It is a liquid crystal device with high reliability and durability.

Therefore, in addition to the conventional liquid crystal device for dimming, it is extremely useful as a liquid crystal device for display of OA equipment such as computers, projections, viewfinders, etc., which is thin and has higher character and graphics. is there.

Claims (3)

[Claims] 1. At least one transparent substrate having an electrode layer, and a dimming layer supported between the substrates,
A liquid crystal device in which the light control layer contains a liquid crystal material and a transparent solid substance, wherein the transparent solid substance is obtained by polymerizing a polymerizable composition containing a polymerizable composition having anaerobic curability. A liquid crystal device characterized by being a substance. 2. The liquid crystal device according to claim 1, wherein the transparent solid substance is formed by polymerizing a photocurable polymerizable composition having anaerobic curability. 3. The liquid crystal device according to claim 1, wherein the light control layer is formed by forming a three-dimensional mesh-like transparent solid substance in a continuous layer of a liquid crystal material.