JPS63271233A - Liquid crystal optical element - Google Patents

Abstract

PURPOSE:To obtain the titled element having excellent appearance, quality, and productivity by interposing a specified photocurable vinyl compd. and a nematic liquid crystal material between pair of the substrate mounted electrode thereon respectively in an uniformly dissolved state, followed by curing it, thereby fixing the phase separation between the nematic liquid crystal material and a cured material. CONSTITUTION:In the titled element which interposes a layer contg. the liquid crystal material between pair of the substrate mounted the electrode thereon respectively, the dissolved material of the photocurable vinyl compd. and the nematic liquid crystal material is disposed between pair of said substrate, and exposed, thereby curing said vinyl compd. resulted in fixing the phase separation between the nematic liquid crystal material and the cured material. Said vinyl compd. is selected so as to coincide the refractive index of the obtd. cured material with either ordinary ray refractive index (n0) or extra ordinary ray refractive index (ne) of the used liquid crystal material. As the liquid crystal and said vinyl compd. are optically cured in uniformly dissolved state of the liquid crystal and the vinyl compd., said materials are fixed in finely ununiform state. Thus, the distribution of the liquid crystal and the cured material becomes uniform, thereby obtaining the excellent appearance, quality and productivity of the titled element.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an element configuration of a transmission random type liquid crystal optical element.

[Light Prior Art] Conventionally, two modes, dynamic scattering (DS) and phase transition (PC), are known for liquid crystal optical elements whose operation principle is light scattering. DS mode is a transparent electrode-equipped substrate that has been subjected to horizontal or vertical alignment treatment, and is filled with a liquid crystal with negative dielectric anisotropy added with a conductive substance. It controls two states: a state in which dynamic scattering is caused by applying a voltage higher than the value voltage, and a state in which transmittance is reduced. In addition, the PC dryer has a cholesteric liquid crystal sealed in a transparent electrode-attached substrate that has been oriented as necessary, and depending on whether or not a voltage is applied, a nematic phase with a homeotropic alignment (transmission) and a cholesteric phase with a focal conic alignment or Brehner alignment (scattering). ). Both DS mode and PC mode do not use polarizing plates, so they have the advantage of providing a wide viewing angle, but the former is a current effect type in which a conductive substance is added to the liquid crystal, so it consumes a lot of power. It has the disadvantage that its reliability is at its lowest point.

On the other hand, even in the latter case, the operating voltage depends on (interelectrode distance/liquid crystal pitch), so when trying to increase the area, there is a difficult problem that requires a highly accurate and uniform gap. . On the other hand, I1. G, Craig
head et al. ^pp1. Phys, Lett.

The method disclosed in 40 (1122 (19821) takes advantage of the characteristic that liquid crystal has refractive index anisotropy. Specifically, a porous body is impregnated with liquid crystal, and the refractive index of the liquid crystal is changed depending on whether or not an electric field is applied. Transmission and scattering are controlled by changing the refractive index of the porous material.This method uses the principle DS mode and PC mode without using a polarizing plate.
This is a possible and useful method to overcome the drawbacks of modes. A similar element is J. L. Fergagon.
Using nematic liquid crystal microencapsulated using polyvinyl alcohol (Published in 1986-501631)
Also, N. Pearlman et al. used various latex-incorporated liquid crystals (Japanese Unexamined Patent Publication No. 60-252687
No.), also J, 11. Doane et al. described a method of dispersing and curing liquid crystals in epoxy resin (published in 1986-502).
No. 128).

[Problems to be solved by the invention] I1. Since the method of G. Craighead et al. uses a method of impregnating a porous material, there are variations in the size of the pores and grooves of the porous material used, it is difficult to impregnate liquid crystal, and there is no flexibility in the amount ratio of porous material and liquid crystal. Due to the problem of lack of transparency, it had disadvantages such as not being able to sufficiently change the transmittance and making it difficult to fabricate elements. Also J, L, Fer
The devices by Gagon et al., K.N., Pearlman et al. use water-soluble polymers or polymers emulsified and dispersed in water when creating the devices, so they have poor water resistance, resulting in clouding and swelling. It had the disadvantage of causing a decline in physical properties. Also, J.J., Doan
A method of curing epoxy resin with ultraviolet rays is disclosed in the method of et al., but since epoxy resin undergoes ionic polymerization but not radical polymerization, it is difficult to cure epoxy resin with the acid produced by decomposing a Lewis acid or protonic acid salt with ultraviolet rays. It performs polymerization.

Therefore, by-products and free acids produced during the decomposition of the salt have resulted in a defect in that the external appearance and reliability of the device are poor.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and provides a liquid crystal optical element in which a layer containing a liquid crystal substance is sandwiched between a pair of electrode-attached substrates. , a photocurable vinyl compound and a nematic liquid crystal material selected so that the refractive index of the resulting cured product matches either the ordinary refractive index (n.) or the extraordinary refractive index (ne) of the liquid crystal material used. The melt is held between a pair of electrode-attached substrates, and exposed to light,
This is a liquid crystal optical element characterized by curing a photocurable vinyl compound and fixing phase separation between a nematic liquid crystal substance and a cured product.

In the device of the present invention, the nematic liquid crystal and the cured product are fixed in a thin non-uniform state by going through a photocuring process from a uniform state in which the liquid crystal and the photocurable vinyl compound are dissolved. The distribution of objects becomes uniform, the appearance quality,
It can be said that it is an element with excellent productivity.

In the present invention, the refractive index of the cured product cured by light exposure is determined by the ordinary refractive index (n
o) or the extraordinary refractive index (ne).

As a result, when the refractive index of the obtained cured product and the refractive index of the liquid crystal substance match, light is transmitted, and when they do not match, light is scattered (cloudy).

Taking advantage of this characteristic, the liquid crystal optical element of the present invention is highly effective when used in a light control body.

In particular, the device of the present invention exhibits a scattering state (that is, a cloudy state) due to the difference in refractive index between the unaligned liquid crystal material and the cured material when no electric field is applied, and when an electric field is applied. In this case, it is preferable that the liquid crystal material is aligned and the refractive index (no or n) of the liquid crystal matches the refractive index of the cured product obtained by photocuring, so that it exhibits a transparent state. This results in an excellent element with excellent light control function.

In particular, if the orientation of the liquid crystal is perpendicular to the substrate surface when an electric field is applied, haze unevenness will occur.Therefore, the transmittance will increase. It is preferable to use a combination of a photocurable vinyl compound selected to match the above and a nematic liquid crystal material with positive dielectric anisotropy.

Note that in the present invention, the refractive index of this cured product is made to match the refractive index (either na or n) of the liquid crystal substance used, but it is preferable that this match be made to match completely. However, it is sufficient to make them approximately coincident to the extent that the transmission state is not adversely affected. in particular,
It is preferable to keep the difference in refractive index to about 0.15 or less.

This is because the cured material swells due to the liquid crystal material and becomes closer to the refractive index of the liquid crystal material than the original refractive index of the cured material, so even if there is a difference of this degree, almost all light will pass through. Become.

The photocurable vinyl compound used in the present invention may be added with a photocuring initiator if the curing speed is to be increased. It is possible to create an excellent device.

This photo-curing vinyl compound may be one in which the compound itself is photoreactive, or one in which curing is induced by a substance generated by light irradiation, and can be roughly divided into those that decompose and harden upon light irradiation and those that undergo monopolymerization. Those that undergo polymerization and curing are further divided into those that undergo photodimerization and those that undergo polymerization and polymerization. Among vinyl groups, many of the former have a cinnamoyl group or a cinnamylidene group, such as polyvinyl cinnamate, polycinnamylidene vinyl acetate, and phenylene diacrylate. The latter is.

Polymers and oligomers are activated by light and polymerize and cure with each other or with other polymers, oligomers, and oligomers, and among vinyl groups, acryloyl, allyl, spiran, and vinylbenzene types are used. 1,000 Tsuma
, oligomers, polymers, etc. Specifically, monoacrylate, diacrylate, N-substituted acrylamide, N-vinylpyrrolidone, styrene and its derivatives, polyol acrylate, polyester acrylate, urethane acrylate, epoxy acrylate,
Examples include compounds with monofunctional and polyfunctional vinyl groups, such as silicone acrylate, fluoroalkyl acrylate, polyacrylate with a polybutadiene skeleton, polyacrylate with an isocyanuric acid skeleton, acrylate with a hydantoin skeleton, unsaturated cycloacetal, etc. be done. In the present invention, these various photocurable vinyl compounds can be used, but the use of acryloyl compounds provides excellent phase separation state and uniformity of the liquid crystal and cured product after light exposure, and The acryloyl group of the acryloyl compound mentioned here is preferred because it has a fast curing speed upon light exposure and the cured product is stable. You can leave it there.

In the present invention, among these photocurable vinyl compounds, those that are polymerized and cured by light irradiation, particularly those containing oligomers that are polymerized and polymerized, are preferred.

Specifically, 15 to 70 wt of acrylic oligomer containing two or more vinyl groups is used as a photocurable vinyl compound.
It is preferable to contain % of liquid crystal light, so that there is less shrinkage due to curing after photocuring. Since minute racks are generated in the element, moldability is improved. If the number of these microcracks increases, the light transmittance in the light transmitting state tends to decrease, and the performance of the element decreases. The viscosity of this acrylic oligomer is preferably about 150 to 50,000 cps at 5[sigma]C since moldability is adversely affected if the viscosity is too high or too low.

For the remaining portion of the photocurable vinyl compound, a vinyl compound can be used. In particular, acrylic mercury is preferred as it has good compatibility with acrylic oligomers.

In the acrylic oligomer preferably used in the present invention, the portion represented by The structure of acrylic acid (CII m・co-co
It is sufficient to have o->. Specifically, the following structures are possible.

(CIt I CII□0) ,, (C,,l+,
0). etc. -(R-0).

1"l+- (R represents an alkylene group, R' represents hydrogen or an alkyl group, and may be substituted with phenylene or cyclohexylene. Also, if multiple R,
When R' etc. are present, they may all be the same group or may be different. Note that these skeletons are merely examples, and may be appropriately selected in consideration of the shape, characteristics, etc. of the element.

Further, the photocurable vinyl compound may be used alone or in combination, and may contain a modifier necessary for producing an element, a modifier for the produced element, and the like. Specifically, it contains crosslinking agents, surfactants, diluents, thickeners, antifoaming agents, adhesion agents, stabilizers, absorbent 1 dyes, polymerization accelerators, chain transfer agents, polymerization inhibitors, etc. It's okay to be there.

The photocurable vinyl compound used in the device of the present invention may be selected from among various materials that meet the requirements described above, taking into account the refractive index of the liquid crystal and the solubility with the liquid crystal.

Further, examples of the photocuring initiator include benzoin ether type, benzophenone type, acetophenone type, and thioxanthone type.

The nematic liquid crystal substance used in the present invention may be used alone or in a composition, but it is more advantageous to use a composition in order to meet various performance requirements such as operating temperature range and operating voltage. .

In addition, the nematic liquid crystal used must be uniformly dissolved in the photocurable vinyl compound, and the cured product after light exposure must be one that does not dissolve or is difficult to dissolve. It is desirable that the solubility of the liquid crystal material be as close as possible.

When manufacturing the device of the present invention, the photocurable vinyl compound and the nematic liquid crystal may be dissolved in a mixture of about 5:95 to 45:55, and may be used as a liquid or viscous substance.

When manufacturing the device of the present invention, the mixture of the photocurable vinyl compound and nematic liquid crystal to be prepared may be liquid or viscous as long as it is uniformly dissolved. Just choose the best one, for example, In
5Os4nO□.

It is generally more convenient to inject in liquid form into cells where glass substrates with transparent electrodes such as SnO□ are placed facing each other and the periphery is sealed. The viscous state is generally more convenient when applying and stacking opposing substrates.

The inter-substrate gap can be operated at 5 to 100 μm, but it is appropriate to set it to 7 to 40 μm, taking into consideration the applied voltage and contrast during on/off.

In this way, the mixture held on the substrate is fixed by light exposure in a phase-separated state of nematic liquid crystal and cured product. Light exposure here generally refers to ultraviolet irradiation or electron beam irradiation. means. Before exposure to light, the content held on the substrate is uniformly dissolved and is colorless and transparent; however, after exposure to light, it becomes cloudy due to refractive index scattering by the unaligned nematic liquid crystal and the cured product. By applying a voltage, the device of the present invention thus produced becomes transmissive because the nematic liquid crystals are aligned and the refractive index matches that of the cured product by 7.

In the present invention, dichroic dyes, simple dyes, or pigments are added to the liquid crystal, colored curable compounds are used, colored substrates are used, or color filters are laminated. You can also add a specific color.

In the present invention, a nematic liquid crystal substance is used as a solvent,
Since the photocurable vinyl compound is cured by light exposure, there is no need to simply evaporate solvents and water that are unnecessary during curing. Therefore, it can be cured in a closed system, making it highly reliable.

In addition, since the photocurable vinyl compound also has the effect of bonding two substrates together, a sealant can be made unnecessary.

For this purpose, a solution of a photocurable vinyl compound and a nematic liquid crystal substance is supplied onto one substrate with electrodes, and then the other substrate with electrodes is placed on top of it, and then light is irradiated to cure it. Manufacturing methods with high productivity can be adopted.

In particular, by using a plastic substrate as the electrode-attached substrate, it is easy to create long liquid crystal optical elements using continuous plastic film! 112 buildings can be built.

By using such a liquid crystal with a matrix of liquid crystal and a curable compound, even if the area is large, the risk of shorting between the upper and lower transparent electrodes is low, and the alignment is similar to that of a normal twisted nematic type display element. There is no need to strictly control the distance between the substrates and the gap between the substrates, and a liquid crystal light control body having a large area can be manufactured with extremely high productivity. Note that in order to reduce unevenness in the state of light transmission, it is preferable that the substrate gap be constant to some extent. For this reason, it is preferable to arrange spacers for controlling the gap, such as glass particles, plastic particles, ceramic particles, etc. in the gap between the substrates. Specifically, a melted material of a photocurable vinyl compound and a nematic liquid crystal substance containing a spacer for controlling the gap between the substrates is supplied onto a substrate with electrodes, or a spacer is supplied before or after the melted material is supplied. , the other electrode-attached substrate may be placed on top of the other. In this case, by applying pressure after overlapping and then curing, a more uniform gap between the substrates can be easily achieved.

Although such a liquid crystal optical element can be used as a display element, it is not suitable for use as a light control body because it can be easily made into a large area and can be cut into a desired size later. be.

When used as a light control body, the electrode is usually a transmissive type, so the electrode is a transparent electrode. Of course, a metal lead portion may also be provided in a part thereof to lower the resistance. Furthermore, when used as a light control mirror, one electrode may be a reflective electrode.

In the case of large liquid crystal optical elements such as this liquid crystal dimmer, if the substrate is made of plastic or thin glass, a protective plate of plastic or glass is laminated for further protection, or the substrate is made of tempered glass, laminated glass, etc. Various applications are possible, such as use of glass, lined glass, etc.

In particular, a liquid crystal optical element is made by using a plastic substrate as a substrate with electrodes, an electrode lead wire is attached, and this is connected between two glass plates that are slightly larger than the liquid crystal optical element through a layer of adhesive material such as polyvinyl butyral. It is preferable to use polyvinyl butyral as the adhesive material by holding the liquid crystal optical element and the glass plate together in a laminated glass form by curing the adhesive material layer by heating or light irradiation. By doing so, it is possible to obtain a structure extremely similar to that of ordinary laminated glass.

To manufacture liquid crystal optical elements like this liquid crystal light control body,
You can manufacture a liquid crystal optical element by preparing two substrates with a desired shape and combining them, or by using a continuous plastic film substrate or a long glass substrate and cutting it later. It may be manufactured by the following method.

This liquid crystal light control body can be used in building materials such as windows, skylights, partitions, and doors, vehicle materials such as windows and moon roofs, and materials such as cases, doors, and lids for various electrical appliances.

When applying a voltage to the liquid crystal optical element of the present invention, it is sufficient to apply an alternating current voltage that changes the alignment of the liquid crystal. Specifically, an AC voltage of about 10 to 1000 Hz may be applied at 5 to 100 square meters.

Furthermore, when no voltage is applied, the electrodes can be opened or short-circuited.Among these, the impedance between the electrodes, that is, the total impedance of the electrode impedance, the connection impedance at the terminal, and the circuit impedance, is By making the impedance lower than that of the layer of nematic liquid crystal material and cured material, the response of the liquid crystal when the voltage is turned off is fast.

In particular, it is preferable that the impedance between the electrodes be 17!0 or less of the impedance of the layer of nematic liquid crystal material and cured product. Therefore, when the impedance of the electrode and the connection impedance at the terminal portion are high, it is preferable to lower the impedance of the circuit.

By forming a self-discharge circuit in this way, even if the capacitance of the element itself is much larger than that of a normal liquid crystal display element, the charge accumulated between the electrodes is quickly discharged, and the liquid crystal display does not inhibit the movement back to a random orientation, and the change between transmission and scattering becomes faster.

The device of the present invention can be used for display devices, especially large-area display devices, curved display devices, etc., which are difficult to use with conventional liquid crystal display devices, as well as large-area light control devices, optical shutters, etc. Many uses are possible.

Further, in the present invention, one of the electrodes may be used as a specular reflective electrode as a mirror, and in this case, the back substrate may be made of opaque glass, plastic, ceramic, or metal.

In addition, color filters can be used together, dichroic dyes can be mixed into the liquid crystal to create colors, and other displays such as TN liquid crystal display elements, electrochromic display elements, electroluminescence display elements, etc. can be stacked together. Various applications are possible.

[Example 1 Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 1 part of n-butyl acrylate and 5 parts of 2-hydroxyethyl acrylate were mixed with liquid crystal (rE-8 manufactured by BDH).
J) and 0.12 parts of benzoin isopropyl ether as a photocuring initiator were uniformly dissolved and placed in a glass substrate cell with ITO having a cell gap of 25 μm. After sealing the injection hole, use an ultraviolet irradiation device (Toshiba Corporation!
When exposed to light for about 60 seconds using a skewer (400J), the entire exposed surface became cloudy, and the element had a structure in which liquid crystal was dispersed in a resin network matrix.

The transmittance of the voltage application section was 18.3%, but AC60
When V (50 Ilz) was applied, the transmittance was 60.2%. (Transmittance meter: Asahi spectral amount! Jl rM-304
) Example 2 1 part of 0-butyl acrylate and 3 parts of 2-hydroxyethyl acrylate, acrylic oligomer (rM-1200J manufactured by Toagosei Kagaku Co., Ltd., viscosity 30000c1) S
150°C) 4 parts, 0.16 parts of Merck's "Talocure-11+6J" as a photocuring initiator, and 4 parts of liquid crystal "E-8".
part was uniformly dissolved. A device was produced in the same manner as in Example 1 except that the cell gap was 10 μm. Voltage application (
＾C60V, 5011z) Transmittance before and after is 3 respectively
They were 8.4% and 77.1%.

Example 3 3 parts of n-butyl acrylate, acrylic oligomer (
Osaka Organic Chemical Industry Co., Ltd. "Viscoat #823J, viscosity 19000 cps/50°C) 2 parts, liquid crystal "E-8"
3 parts of [Talocure-11+6J] and 0.1 part of Tarocure-11+6J were uniformly mixed and applied using a doctor blade onto an ITO-attached polyester film temporarily adhered to a glass substrate. Next, a polyester film with ITO which had been temporarily adhered to a glass substrate in the same manner was superimposed, the cell gap was adjusted using a 10 μm spacer, and the film was exposed to light under the same conditions as in Example 1 to produce a device.

The transmittance before and after voltage application (^C60V, 5011z) was 42.8% and 67.1%, respectively.

Example 4 1 part of n-butyl acrylate, 5 parts of 2-hydroxyethyl acrylate, acrylic oligomer (rM-6200J manufactured by Toagosei Kagaku Co., Ltd., viscosity 240 cps, 150°C)
), 0.20 parts of Talocure 1173J manufactured by Merck & Co., Ltd. as a photocuring initiator, and 18 parts of Liquid Crystal rE-8J were uniformly dissolved. The glass plate thickness of the cell used was 3.
A device was produced in the same manner as in Example 1, except that the light was set to On+m and the light exposure time was set to 3 minutes. Voltage application (AC60
V, 50Hz) Transmittance before and after is 8.3%% respectively
It was 52.0%.

Example 5 1 part N-(n-butoxymethyl]-acrylamide, n
-butyl acrylate 3 parts, [Tarocur 1lI6J
0.2 parts, liquid crystal Roche rTN-623J
9.5 parts were uniformly dissolved. Cell gap 10μm
A device was produced in the same manner as in Example 1, except that. The transmittance before and after voltage application (AC60V, 50112) was 79.1% and 85.0%, respectively.

Example 6 n = 12 parts of butyl acrylate, acrylic oligomer r
M-1200424 part, “Tarocure 11+6J
1.4 parts and 64 parts of liquid crystal r E-8J were uniformly dissolved.

As in Example 3, a polyester film with ITO was temporarily adhered to a glass substrate, superimposed so that the cell gap was 4 μm, and exposed to an ultraviolet irradiation device (manufactured by Mitsubishi Electric Corporation).
Approximately 90% by using LumiSuba (30W) J)
A device was fabricated by second light exposure.

The transmittance when no voltage is applied is 1093%, and the transmittance after voltage is 62.5% (AC15V, 5011z
), 77.7% (AClooV, 5011z).

Furthermore, this was sandwiched between two glass plates with two polyvinyl butyral films interposed therebetween, and heated and pressurized in an autoclave to integrate them.

The light control body integrated in this way was safe against external pressure and had high reliability.

Example 7 A device was produced in the same manner as in Example 6 except that the cell gap was 8 μm. The transmittance when no voltage is applied is 1
9.8%, transmittance after voltage application 1; t75.3 parts% (
AC15V, 50Hz), 77.2% (AC3
0V.

5011z).

Example 8 In the element of Example 6, the response time for transmittance change when the circuit was opened from a state where a voltage of %ACbOV was applied was 1.2 seconds. After the voltage was turned off, both electrodes of the device were short-circuited through a resistor of IkΩ, and the response time was 0.
It was 0.02 seconds.

Example 9 An element was produced in the same manner as in Example 6, except that 1.5 parts of Best Cure 161 J manufactured by Toka Shiki Kagaku Kogyo Co., Ltd. was added and dispersed as a colored cured product.

A device that is uniformly colored on the entire surface is obtained, and the transmittance is 8.1% when no voltage is applied, and the transmittance after voltage is 63.5.
% (AClooV, 50Hz).

Example 10 7 parts n-octyl acrylate and 15 parts 2-hydroxyethyl acrylate, acrylic oligomer rM
-1200J 14 parts, liquid crystal [E-8464 parts] were uniformly dissolved in 3 parts of benzoin isopropyl ether as a photocuring initiator. ITO temporarily adhered to a glass plate with this solution
Then, the ITO-attached polyester film substrate was temporarily bonded to a glass plate in the same way, and the ITO-attached polyester film substrate was stacked so that the cell gap was 14 μm, and then the UV irradiation bag was placed! 2! When exposed to light for about 60 seconds using "Toscure 400", an element with a cloudy exposed surface was obtained.

The transmittance before voltage application was 15.9%, but ACl
When 00V (50112) was applied, the transmittance was 77.0%.

Example 11 1 part of N-(n-butoxymethyl)-acrylamide,
3 parts of n-butyl acrylate, acrylic oligomer [
Visco) #823J 1 part, photocuring initiator "Darocure+6J Q, 2 parts, liquid crystal rTN-623J
9.5 parts were uniformly dissolved. A device was produced in the same manner as in Example 5 except that the cell gap was 10 μm.

The transmittance before and after voltage application (AC60V, 5[111z) was 76.2% and 85.2%, respectively.

This element uses an acrylic oligomer as a raw material, and compared to the element of Example 5, there were fewer microcracks after curing and the transmittance changed more greatly when voltage was applied.

[Effects of the Invention] As described above, the present invention provides a novel liquid crystal optical element, and the refractive index of the obtained cured product is the same as the ordinary refractive index (no) or the extraordinary refractive index of the liquid crystal material used. (ne
) and a nematic liquid crystal substance are held in a uniformly dissolved state between a pair of electrode-attached substrates, and the photocurable compound is cured by light exposure to form a nematic liquid crystal material. This is an element in which phase separation between the liquid crystal material and the cured material is fixed. Therefore, the present invention is an element that does not require a polarizing plate and has excellent appearance quality and productivity, and is widely used for displays, especially large area and curved displays, as well as large area dimming, light shutters, etc. can be used.

In the present invention, since a photocurable vinyl compound is used, the device has high reliability and has a laminated glass-like structure, and is highly safe and resistant to breakage due to external pressure.

Furthermore, by providing a protective plate on at least one side of this substrate, safety is improved, and in particular, by providing protective plates on both sides, damage becomes less likely to occur.

In particular, by supplying a solution of a nematic liquid crystal substance, a photocurable vinyl compound, and, if necessary, a photocuring initiator on a substrate, and placing the other substrate on top of it, a large-area device can be fabricated. can be manufactured with extremely high productivity. For this reason,
In the case of glass, quite long substrates can be used, and in the case of plastic substrates, continuous processes using continuous films are also possible.

Particularly, when a plastic substrate is used as a substrate, although productivity is good, the strength is poor, so that when the area is increased, the substrate is easily damaged or bent. Therefore, the effect of providing protective plates on both sides is great. In particular, by using a glass plate as a protective plate and bonding it with an adhesive material, it has a structure similar to single laminated glass, making it safe and reliable.

Furthermore, since the liquid crystal optical element of the present invention has a fine three-dimensional network matrix made up of the liquid crystal material and the hardened vinyl compound, the element can be cut into a desired size after manufacturing. I'll come.

In addition, since the liquid crystal dispersions are connected to each other in the matrix, the liquid crystals tend to align uniformly when a voltage is applied, so compared to elements composed of microcapsules or independent liquid crystal particles, the liquid crystals are more easily aligned in the transparent state. It also has the effect of reducing haze, requiring a low driving voltage, and preventing the element from becoming reddish in a cloudy state.

The present invention can be applied in various other ways as long as the effects of the present invention are not impaired.

Procedural amendment March/r day, 1986

Claims (11)

[Claims] (1) In a liquid crystal optical element formed by sandwiching a layer containing a liquid crystal material between a pair of electrode-attached substrates, the refractive index of the obtained cured product is the ordinary refractive index (n_o) or the extraordinary light refractive index of the liquid crystal material used. A melt of a photocurable vinyl compound and a nematic liquid crystal substance selected to match one of the refractive indexes (n_e) is held between a pair of electrode-attached substrates, and the photocurable vinyl compound is cured by light exposure. A liquid crystal optical element characterized by being cured to fix phase separation between a nematic liquid crystal substance and a cured product. (2) A photocurable vinyl compound selected so that the refractive index of the resulting cured product matches the ordinary refractive index (n_o) of the nematic liquid crystal used, and a nematic liquid crystal material with positive dielectric anisotropy. A liquid crystal optical element according to claim 1 for use. (3) The liquid crystal optical element according to claim 1, wherein the photocurable vinyl compound used is an acryloyl compound. (4) The liquid crystal optical element according to claim 3, wherein the photocurable vinyl compound used is an acrylic ester compound. (5) The liquid crystal optical element according to claim 4, wherein the photocurable vinyl compound used contains 15 to 70 wt% of an acrylic oligomer. (6) The liquid crystal optical element according to claim 1, wherein the electrode-attached substrate is a transparent electrode-attached substrate. (7) The liquid crystal optical element according to claim 6, wherein the substrate with transparent electrodes is a plastic substrate with transparent electrodes. (8) The liquid crystal optical element according to claim 6 or 7, wherein a protective plate is laminated on the outside of the transparent electrode-attached substrate. (9) The liquid crystal optical element according to claim 8, wherein the protective plate is adhered to the outside of both transparent electrode-attached substrates. (10) The liquid crystal optical element according to claim 8 or 9, wherein the protective plate is a glass plate. (11) A liquid crystal optical element according to claim 10, wherein the glass plates are bonded with polyvinyl butyral to form a laminated glass-like structure.