JPH0833559B2 - Liquid crystal optical element manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a transmission / scattering type liquid crystal optical element and its use.

[Prior Art] In recent years, a transmission-scattering control type liquid crystal in which a film-shaped liquid crystal layer in which a liquid crystal substance is filled in voids of a resin matrix is sandwiched between a pair of substrates with electrodes is used. Optical elements are receiving attention.

HG Craighead et al. Appl. Phys. Lett., 40 (1) 22 (198
It is disclosed in 2), and it makes use of the feature that liquid crystal has refractive index anisotropy. Specifically, the porous body is impregnated with liquid crystal, the refractive index of the liquid crystal is changed depending on whether or not a voltage is applied, and the refractive index with the porous body is adjusted to control transmission and scattering. This method is a useful method that can overcome the drawbacks of the fundamental DS mode and PC mode without using a polarizing plate.

A similar device was used by JL Fergason et al. With nematic liquid crystals microencapsulated using polyvinyl alcohol (publication number 58-501631), and by KN Pearlman et al. With various latex uptake liquid crystals (JP-A-60-252687).
No.), and JWDoane et al. Make it by a method of dispersing and hardening a liquid crystal in an epoxy resin (publication No. 61-502128).

[Problems to be Solved by the Invention] Since the method of HGCraighead et al. Uses means such as impregnation into a porous body, the sizes of pores and grooves of the porous body to be used vary, the impregnation of liquid crystal is difficult, Due to the problem that there is no degree of freedom in the quantity ratio between the body and the liquid crystal, there are drawbacks in that a change in transmittance cannot be sufficiently obtained, and that it is difficult to prepare an element.

In addition, the element by JL Fergason et al., Or KN Pearlman et al., Cannot be cured with the two substrates sandwiched because the curing progresses with the evaporation of water, and there is no adhesiveness between the two substrates. It was difficult to fabricate a device having a large area and high flatness.

In addition, when trying to create an element with a change in transmission-scattering state, it is necessary to evaporate water when curing the film-like liquid crystal layer in these elements, so the film-like liquid crystal layer is sandwiched between the substrates with electrodes. Can not. Therefore, it is necessary to pattern the electrodes required for display.

Also, in the element of JW Doane et al., When the film-like liquid crystal layer is formed on a large-area substrate, the uncured film-like liquid crystal layer is applied and handled, so that the control of the thickness thereof tends to be insufficient, and in particular Uniform coating was extremely difficult to form a film-like liquid crystal layer on the substrate.

[Means for Solving Problems] The present invention has been made to solve the above-mentioned problems, and the refractive index of the liquid crystal substance and the obtained cured product is the ordinary light refractive index (n _{o) of the} liquid crystal substance. ), An extraordinary light refractive index (n _e ) or a refractive index (n _x ) when the liquid crystal substance is randomly oriented, and a curability that is compatible with the liquid crystal substance. A latex comprising a compound and a polymer substance selected so as to match the refractive index of a cured product of this curable compound is supplied onto one electrode-attached substrate, and water is evaporated to form a matrix of the polymer substance. A semi-cured film-like liquid crystal layer filled with a dissolved mixture of a liquid crystal substance and a curable compound is formed in the void portion, and the other substrate with an electrode is superposed thereon and cured to cure the curable compound and the liquid crystal. Immobilize phase separation with substances to A method for producing a liquid crystal optical element, characterized by forming a film-like liquid crystal layer filled with a liquid crystal substance in a void portion of a matrix of a child substance and a cured product, and at least a portion of an electrode desired to be kept in a specific alignment state While applying a voltage, mask the part other than the part you want to keep in a specific orientation and light-exposure to cure, then remove the mask and cure the uncured part without applying a voltage, or specify Mask the part you want to keep in the alignment state, cure the parts other than the part you want to keep the specific alignment state by light exposure, then remove the mask, and at least apply a voltage to the electrode in the part you want to keep the specific alignment state. The present invention provides a method for manufacturing a liquid crystal optical element, characterized in that an uncured portion is cured while applying a voltage.

The device of the present invention uses a latex composed of a liquid crystal substance, a curable compound that can be dissolved in the liquid crystal substance, and a polymer substance, and has two curing processes: a curing process of the polymer substance by evaporation of water and a curing process of the curable compound. Through the process, a structure in which a liquid crystal substance is dispersed in the matrix of a cured product of a polymer substance and a curable compound, the liquid crystal and the cured product are evenly distributed, and it is homogeneous and has excellent appearance quality and productivity. Is.

In the present invention, the refractive index of the cured product obtained by curing the curable compound is the ordinary refractive index (n _o ) of the liquid crystal substance used in either the state in which no voltage is applied or the state in which voltage is applied. , The extraordinary light refractive index (n _e ) or the refractive index (n _x ) when the liquid crystal substance is randomly aligned. Further, the refractive index of the polymer substance is made to match the refractive index of the cured product obtained by curing the curable compound.

As a result, light is transmitted when the refractive index of the resin matrix of the formed film-like liquid crystal layer and the refractive index of the liquid crystal substance filled in the voids match, and light is scattered (white turbidity) when they do not match. It will be.

Taking advantage of this characteristic, the liquid crystal optical element of the present invention has a large effect when used as a light control body.

Further, in the element of the present invention, the refractive index of the polymer substance of the cured product and latex obtained by curing the curable compound constituting the resin matrix is the same as that of the liquid crystal substance used.
By matching with n _o or n _e , when a voltage is not applied, a scattering state (that is, a cloudy state) is exhibited due to the difference in refractive index between the liquid crystal substance that is not aligned and the resin matrix. If a voltage is applied, the liquid crystal material is arranged, which shows the transmission state by the refractive index of the liquid crystal and (n _o or n _e) and the refractive index of the resin matrix are matched, reversible dimming function Will have.

The film-like liquid crystal layer of the device of the present invention is formed by performing two curing processes, a curing process of a polymer substance by evaporation of water and a curing process of a curable compound.

In the present invention, a mixture of a curable compound, a liquid crystal substance and a polymer substance is used. This mixture constitutes latex, and can be easily supplied to the electrode-attached substrate to form a thin film, and even when supplied to a large area, it can have a relatively uniform thickness.

The first half of the curing step is a step in which the polymer substance is cured by evaporation of water in the latex, and the polymer constitutes a matrix, and the dissolved mixture of the liquid crystal substance and the curable compound is formed in the void portion of the matrix. A semi-cured film-like liquid crystal layer having a filled structure is formed. In this state, since the refractive indexes of the two do not usually match, a scattering state occurs.

In the latter curing step, the other substrate with electrodes is superposed on the semi-cured film-like liquid crystal layer, and the curable compound is cured by heating or light exposure. This allows
In the previous step, the uncured curable compound is phase-separated from the liquid crystal substance to be cured, and forms a matrix together with the already cured polymer substance.

In this state, the cured product obtained from the curable compound and the polymer are made to have the same refractive index. Therefore, as described above, the resin matrix and the liquid crystal substance have the same refractive index. If not, the film-like liquid crystal layer is in a scattering state.

In the present invention, in the latter half of the curing step, a specific orientation is formed by curing with a voltage applied only to a specific portion. Normally, by curing under a condition where a voltage equal to or higher than the threshold voltage is applied, the portion is always in a light transmitting state.

However, since there is a difference in the alignment formation with respect to the applied voltage depending on the system of the curable compound and the liquid crystal substance used,
Even if a voltage equal to or higher than the threshold voltage is applied, the light transmission state may not always occur. Therefore, a voltage sufficiently higher than the threshold voltage is applied or the composition of the system is appropriately selected.

After curing, light is almost transmitted through this portion regardless of the application of voltage. As a result, specific characters and figures can be displayed without patterning the electrodes. Also,
It is also possible to easily surround characters, figures, graphs, and the like with a continuous frame, and there is an advantage that the degree of freedom of display and the ease of designing display patterns are improved.

In other areas where no voltage is applied or where a low voltage is applied, the part is cured while the voltage is applied but the area is short, light is transmitted to some extent, and the transmittance of light is increased by applying the voltage. Changes.

In this case, when the liquid crystal substance is cured by photoexposure while applying a voltage that does not completely align it, or is cured by applying a voltage for a short time so that the curing proceeds to some extent. In such a case, the liquid crystal molecules will be oriented with an angle of inclination to the substrate surface on average.

As a result, the transmittance of light when no voltage is applied is higher than that of the surrounding cloudy part, and halftone display is possible. As a result, it is possible to display like a photograph.

If you want to display a halftone like a photo, use a photocurable compound as the curable compound, and apply a high voltage while using a negative or positive of the photo to perform photoexposure. A liquid crystal optical element can be obtained.

As a result, a place where the light is strongly applied is always in the transmission state, and the smaller the amount of the light is applied, the stronger the scattering degree is. This makes it possible to produce various halftones depending on the amount of transmitted light. It is possible to control scattering and transmission of the portion in the scattering state by applying a voltage.

For the purpose of forming a portion through which light is constantly transmitted according to the present invention, the threshold of the liquid crystal of the liquid crystal optical element is obtained by curing while applying a voltage so as to form a specific orientation. The value of the dielectric constant (ε) measured below the voltage and the dielectric constant measured in the two states of the liquid crystal optical element in the cured portion without applying a voltage, that is, (1) the liquid crystal is sufficiently perpendicular to the substrate Dielectric constant (ε _ON ) measured at a voltage at which alignment is possible (2) Dielectric constant (ε _ON ) measured below the threshold voltage of liquid crystal
_OFF ) is preferably as follows.

In addition, when the transmittance in the scattering state is increased instead of always in the transmitting state by the method as described above, the transmission-scattering can be controlled by the presence or absence of the voltage application, and the transmission-
There is a tendency that the response speed of scattering becomes faster and the driving voltage becomes lower. Therefore, there is also a method of use in which a specific orientation is formed by applying a voltage to cure the curable compound within a range where the transmittance in the scattering state is not so high. In this case, a voltage is applied to the film-like liquid crystal layer on the entire surface of the device to cure it.

In particular, since the transmittance increases when the liquid crystal orientation when a voltage is applied is perpendicular to the substrate surface, the resin matrix, that is, the polymer substance forming the latex and the curable compound, are cured. The refractive index of both the cured product and
It is preferable to use a combination of a photo-curable compound selected so as to match n _{o of} the liquid crystal substance used and a liquid crystal substance having a positive dielectric anisotropy.

Further, in the device of the present invention, the refractive index of the cured product of the curable compound and the refractive index of the polymer substance match the refractive index (n _x ) when the liquid crystal substance used is randomly aligned. It can also be done.

The term "random alignment" used herein means that not all liquid crystal molecules are arranged parallel or perpendicular to the substrate surface, but are oriented in various directions due to the influence of the mesh or capsule constituting the matrix of the cured product. Indicates that. In this case, when no voltage is applied, the liquid crystal substance that is not aligned (randomly aligned) and the resin matrix have the same refractive index, and thus shows a transmissive state.

Conversely, when a voltage is applied, the liquid crystal substance is aligned,
Refractive index of the liquid crystal and (n _o or n _e) and the refractive index of the resin matrix will not match, scattering state (i.e. opaque state)
Will be shown. By these, a transparent element can be obtained without applying a voltage, but it is similar to the case where the resin matrix exists in the form of a mesh or capsule and the liquid crystal is randomly oriented under the influence of the cured product of the resin matrix. Because of the situation, there is a problem that it is difficult to make a uniform state.

This is because when oriented vertically or horizontally like the former, it is easy to orient uniformly, but randomly oriented is random when viewed macroscopically, but partially when oriented. Is slightly different, causing a difference in refractive index,
This is because it becomes uneven and easy to see.

This type of element is, similarly to the case described above, cured by applying a voltage equal to or higher than the threshold voltage only to a specific portion during the curing step of the curable compound in the latter half, thereby curing that portion. Can always be in a scattered state.

This portion scatters light after curing regardless of the application of a voltage. As a result, specific characters and figures can be displayed without patterning the electrodes.

Also in the case of this element, whether the liquid crystal substance is cured by light exposure while applying a voltage to such an extent that the liquid crystal substance is not completely aligned,
Alternatively, the liquid crystal molecules can be aligned at a certain angle with respect to the substrate surface by averaging the liquid crystal molecules by, for example, curing by light exposure for a short time such that the voltage is applied and the curing proceeds to some extent. This makes it possible to display a halftone like a photograph or to drive at a low voltage.

Also in this case, since the alignment formation with respect to the applied voltage differs depending on the system of the curable compound and the liquid crystal substance used, it is preferable to experimentally determine the applied voltage depending on the desired alignment state.

In the present invention, the refractive index of this resin matrix,
It is intended to match the refractive index (any of n _o , n _e , and n _x ) of the liquid crystal substance to be used, and it is preferable that this match is perfectly matched, but it does not adversely affect the transmission state. It is good enough that they are almost the same so that they are not given.

Specifically, the difference between the refractive index of the polymer substance of the latex, the refractive index of the curable compound, and the refractive index of the liquid crystal substance is calculated.
It is preferable to set it to about 0.15 or less. This is because the polymer substance or the cured product swells due to the liquid crystal substance and comes closer to the refractive index of the liquid crystal substance than the refractive index originally possessed by the polymer substance or the cured product. , The light is almost transmitted.

In the present invention, as the curable compound, a compound which does not cure when the polymer substance of the latex is cured by evaporation of water and is then cured by heat, light or the like can be used. In particular, a photocurable compound has a short curing time and good productivity, and it is possible to easily form a specific orientation in a desired portion without patterning the electrode only by blocking light with a mask,
A fixed display portion can be formed. That is, by arranging a mask that blocks light on the surface of the substrate, it is possible to easily cure only a specific portion to form a specific orientation, and a fixed display in which light is always transmitted or scattered. The part can be formed.

The photo-curing property may be a compound that is cured by infrared rays, visible rays, ultraviolet rays or electron beams. The action of the light may be any as long as it accelerates curing, and may be any of photons, electrons and heat.

Therefore, the photocurable compound is vinyl polymerization, addition polymerization,
Although any of condensation polymerization, cationic polymerization, anionic polymerization, living polymerization and the like may be used, condensation polymerization which generates a substance that may deteriorate the liquid crystal substance such as water and a corrosive substance is generally not preferable.

Moreover, after masking and photocuring, the whole may be heated to perform thermal polymerization.

When using a photo-curable compound, if you want to increase the curing speed, you can add a photo-curing initiator, and if it is photo-curable by radical species, create an element with excellent appearance and reliability. can do.

This photocurable compound may be a compound which itself has photoreactivity or a compound which is induced to be cured by a substance generated by light irradiation. When roughly classified, it is decomposed and cured by light irradiation and polymerized and cured. Classified as one.

Typical examples of these compounds include photocurable acrylic monomers and oligomers, and specifically, monoacrylate, diacrylate, N-substituted acrylamide, N-vinylpyrrolidone, styrene and derivatives thereof,
Polyol acrylate, polyester acrylate,
Monofunctional and polyfunctional vinyl groups represented by urethane acrylate, epoxy acrylate, silicone acrylate, fluoroalkyl acrylate, polyacrylate having a polybutadiene skeleton, polyacrylate having an isocyanuric acid skeleton, acrylate having a hydantoin skeleton, and unsaturated cycloacetal. Compounds having are exemplified.

In particular, among the photocurable compounds, the use of an acrylic compound is excellent in the phase separation state and uniformity of the liquid crystal and the cured product after photoexposure, and the curing speed by photoexposure is fast. It is preferable because the product is stable.

The curable compound may be used singly or in a mixture of two or more, and a modifier necessary for element production, a modifier for the element produced, and the like, specifically, a crosslinking agent, a surfactant, a diluent, Thickener, defoaming agent, adhesiveness imparting agent, stabilizer, absorbent, pigment,
It may contain a polymerization accelerator, a chain transfer agent, a polymerization inhibitor and the like.

The curable compound used in the device of the present invention may be selected from various materials satisfying the above requirements in consideration of the refractive index of the liquid crystal and the solubility with the liquid crystal.

Examples of the photo-curing initiator include benzoin ether type, benzophenone type, acetophenone type and thioxanthone type.

The liquid crystal substance used in the present invention includes a nematic liquid crystal substance, a smectic liquid crystal substance and the like, and they may be used alone or as a composition, but in order to satisfy various required performances such as an operating temperature range and an operating voltage. It can be said that it is advantageous to use the composition. In particular, the use of nematic liquid crystal is preferable.

Further, it is preferable that the liquid crystal substance to be used is uniformly dissolved in the curable compound, and it is necessary that the liquid crystal substance does not dissolve or is difficult with the cured product after photoexposure. It is desirable that the solubility of the liquid crystal substance is as close as possible.

The polymer substance constituting the latex used in the present invention contains a solution of the above liquid crystal substance and a curable compound,
What is necessary is that it becomes a stable latex. Specifically, as the vinyl-based polymer, polyvinyl acetate, polystyrene, polyethylene, polyvinyl chloride, an acrylic copolymer, a vinyl acetate polymer, a vinylidene chloride copolymer, a vinyl chloride copolymer, etc. Polyisobutylene, chloroprene rubber, polybutadiene rubber, SBR, N
In addition to BR, MBR, etc., polyurethane, polyepoxy, polysiloxane, etc. are exemplified, and various additives may be contained in order to ensure the stability of the latex.

The polymeric material in this latex hardens (meaning it solidifies rather than polymerize) upon evaporation of water to form the framework of the resin matrix.

When manufacturing the device of the present invention, the total amount of the curable compound and the polymer substance, and the amount of the liquid crystal substance is 5:95 to 75: 2 by weight ratio.
A mixture of about 5 may be used, and a liquid form may be used as a viscous substance. In this case, the weight ratio of the curable compound and the polymer substance may be usually about 10:90 to 90:10.

 A method for manufacturing the device of the present invention will be exemplified below.

First, a polymer substance that constitutes a latex is added to a dissolved mixture of a curable compound and a liquid crystal substance to form a stable latex in which they are mixed. In this latex, a dissolved mixture of a liquid crystal substance and a curable compound is in a state of being dispersed in a polymer substance dispersed in water.

This latex is supplied onto a glass substrate with a transparent electrode such as In ₂ O ₃ -SnO ₂ (ITO) or SnO ₂ by roll coating, spin coating, printing, etc. to evaporate water and semi-cure. A film-like liquid crystal layer in the state is formed. In this state,
In the film-like liquid crystal layer, the polymer substance is solidified to form a framework of the resin matrix, and the dissolved mixture of the liquid crystal substance and the curable compound is dispersed and present in the voids.

Then, on the semi-cured film-like liquid crystal layer,
Substrates with electrodes facing each other are superposed and exposed to light or heated to cure the curable compound. As a result, from the dissolved mixture of the liquid crystal substance and the curable compound dispersed in the voids of the framework of the resin matrix in which the polymer substance is solidified, the curable compound is cured and phase-separated from the liquid crystal substance, and A film-like liquid crystal layer in which a liquid crystal substance is dispersed is formed in a void portion in a resin matrix composed of a cured product of a curable compound.

At the time of curing the curable compound, it is cured while applying pressure, curving the substrate to be cured, or applying a voltage when necessary.

Further, it is also possible to cure the curable compound without superimposing the other electrode-attached substrate and to bond the other electrode-attached substrate after the curing.

The thickness of the film-like liquid crystal layer in this cured state is 5
It is possible to operate at up to 100 μm, but it is suitable to set at 7 to 40 μm in consideration of the applied voltage and the contrast at the time of on / off.

In this way, the polymer substance in the latex is first cured and then the curable compound is cured to form a film-like liquid crystal layer.

In this case, the refractive index of the cured product, when exactly match the refractive index of the cured product and the polymer material constituting the resin matrix, and n _o or n _e of the liquid crystal material is arranged and after curing The liquid crystal substance and the resin matrix do not become white due to the refractive index scattering. In the element of the present invention thus produced, the liquid crystal substance is aligned by applying a voltage,
Since the refractive index of the resin matrix and the refractive index of the aligned liquid crystal substance match, the resin matrix is in a transmissive state.

In the present invention, when it is desired to cause a specific orientation of the fixed display at this time, the curable compound is cured while applying a voltage only to this portion.

There are various methods for producing this specific orientation, but it is preferable to use a photocurable compound as the curable compound and to perform photoexposure because of good productivity, and examples thereof will be shown below.

An electrode corresponding to the pattern of a specific portion is arranged, and light is applied to the whole while applying a voltage between the electrodes to cure the electrode.

Form a light-shielding mask on the part except the specific part,
While applying a voltage to at least a specific portion, light is applied to the entire portion to cure only the specific portion, and then the light shielding mask is removed to cure the remaining portion.

A voltage is applied to a necessary portion while scanning with a laser or the like to form a specific orientation only on a specific portion.

Further, these steps may be combined, or the process may be reversed so that the portion excluding the specific portion is cured first by using a mask having the same shape as the specific portion.

In particular, the reverse process can use an electrode for driving an unpatterned element formed in advance on the substrate, and only a mask is required as a means for adding, and the productivity is also good.

Further, the cell structure of a normal liquid crystal optical element having an electrode formed on the inner surface thereof may be adopted, and the electrode may be used to form a specific pattern in a specific orientation, or the electrode may be arranged outside to thereby form a specific pattern. May have a specific orientation. With these, for example, a dot matrix display, a segment display, a bar graph display can be combined with a figure, or a continuous frame can be formed.

Further, for example, a disk-shaped glass substrate cell with ITO on the entire surface can be used as a memory element by writing with a laser beam or the like using a method while rotating at the center.

Furthermore, as described above, the voltage during curing is changed stepwise near the threshold voltage, and the white turbidity is low by controlling the light irradiation time, the curing temperature, etc., but the transmittance changes depending on the voltage. You may form the halftone transmissive part.

The element thus created is normally cloudy or slightly cloudy with a portion where light is always transmitted due to a specific orientation, but when a voltage is applied, liquid crystals are aligned and a cured product is obtained. Since the refractive index of the liquid crystal layer and the refractive index of the liquid crystal coincide with each other to enter the transmissive state, there is a portion where the transmissivity changes.

Further, by appropriately selecting the system of the curable compound and the liquid crystal substance, the applied voltage, the intensity of light, etc., the control range of transmission-scattering is not so narrowed, that is, the degree of white turbidity when the voltage is off is not so much. It is possible to increase the response speed or reduce the drive voltage without dropping the voltage.

Also, when the refractive index of the resin matrix is made to match the refractive index (n _x ) of the liquid crystal substance, the refractive index of the liquid crystal substance not aligned after curing and the refractive index of the resin matrix match, so Become. In the device thus produced, when a voltage is applied, the liquid crystal substance is aligned, and the refractive index of the resin matrix and the refractive index of the aligned liquid crystal substance are deviated and scattered.

In this case, if a specific orientation is formed, light will always be scattered at that portion. Of course, also in this case, as in the case described above, it is possible to form a halftone portion, increase the response speed, and decrease the drive voltage.

In the present invention, in the liquid crystal, a dichroic dye or a simple dye,
It is also possible to add a specific color by adding a pigment, using a colored substance as a polymer substance or a curable compound, using a colored substrate as a substrate, or laminating a color filter.

In the present invention, the latex is supplied to the substrate, the water is evaporated to cure the polymer, and the polymer is brought into a semi-cured state, so that it can be rapidly supplied to a large area and its thickness can be relatively easily made uniform. .

Next, the curable compound is cured to separate the liquid crystal substance by phase separation, and the curing of the film liquid crystal layer is completed. During the latter half of curing, it is not necessary to simply evaporate the solvent or water. Therefore, since it can be cured in a closed system, it is highly reliable, and since it also has the effect of adhering two substrates with a photocurable compound, a sealant can be eliminated. Further, in this step, both substrates can be held under pressure, so that the substrate gap can be made more uniform. At this time, even if the pressurizing pressure is strong, the resin matrix is already formed of the polymer substance, so that there is little risk of short circuit between the substrates and the productivity is good. Therefore, by bending the substrate having the semi-cured film-like liquid crystal layer and then performing the latter curing step, the element of the curved substrate can be easily manufactured. Further, as described above, it is possible to easily perform a fixed display by forming a specific orientation on a specific portion.

In the present invention, as the electrode-attached substrate, a substrate obtained by forming a transparent electrode such as ITO or SnO _{2 on} a substrate such as glass or plastic can be used. Of course, by forming an insulating layer between the substrate and the electrode, using a low resistance metal lead wire together with the electrode, forming a mirror surface electrode on one electrode, forming a non-glare layer on the front side of the substrate Good. In particular, by using a plastic substrate as the substrate, a long liquid crystal optical element using a continuous plastic film can be easily manufactured.

By sandwiching the film-like liquid crystal layer between such electrode-attached substrates, the risk of short-circuiting between the upper and lower transparent electrodes is low even when the area is large, and the orientation is similar to that of a normal twisted nematic display element. It is not necessary to strictly control the substrate gap and the liquid crystal light control body having a large area can be manufactured with extremely high productivity.

In the device of the present invention as well, in order to reduce unevenness in the light transmission state, it is preferable that the substrate gap be constant to some extent. For this reason, it is preferable to dispose a spacer for controlling the gap such as glass particles, plastic particles, and ceramic particles in the gap between the substrates. Specifically, the spacer for controlling the substrate gap may be contained in the latex on the substrate and supplied, or the spacer may be supplied before or after the latex is supplied, and then the water may be evaporated.

In this case, it is easy to form a more uniform substrate gap by applying pressure after stacking the other substrate and then curing the curable compound.

Such a liquid crystal optical element can be used also as a display element, but is suitable when used as a dimmer because it can be easily enlarged to a large area and can be cut into a desired size later. . When used as a dimmer, the electrode is usually a transparent electrode because it is a transmission type. Of course, a metal lead portion for lowering the resistance may be provided together with a part thereof. When used as a dimming mirror, one of the electrodes may be a reflective electrode.

In this liquid crystal optical element, when the substrate is plastic or thin glass, a protective plate such as plastic or glass may be laminated for protection, or the substrate may be tempered glass, laminated glass, lined glass, etc. Can be applied.

In particular, a plastic substrate is used as a substrate with electrodes to make a liquid crystal optical element, and an electrode lead-out line is provided, and this is interposed between two glass plates slightly larger than the liquid crystal optical element via an adhesive material layer such as polyvinyl butyral. Preferably, the adhesive material layer is cured by heating or light irradiation, and the liquid crystal optical element and the glass plate are integrated to form a laminated glass. Above all, by using polyvinyl butyral as the adhesive material, a structure very similar to ordinary laminated glass can be obtained.

In order to manufacture this liquid crystal optical element, two substrates having a desired shape may be prepared and combined to manufacture a liquid crystal optical element, or a continuous plastic film substrate may be used, or a long glass substrate may be used. It may be manufactured by using the method described above and then cut.

The use of the light control body using this liquid crystal optical element includes a window,
It can be used for building materials such as skylights, partitions and doors, vehicle materials such as windows and moon roofs, cases, doors and lids for various electric products.

In the case where the liquid crystal optical element is used as a dimmer, a driving unit for driving the liquid crystal optical element may be added.
As the driving means, a driving means which can apply an AC voltage of about several tens of volts as described later is used.

In addition, by combining this liquid crystal optical element as an arrangement means for arranging various objects and adding a driving means for driving the same, it is used for an object exhibit such as a show window or a showcase for displaying various products. You can also do it. To do this, use it on the file shelf to see the file title without applying a voltage to make it transparent,
There is also an application in which the presence or absence of a file can always be confirmed by the transparent part.

Further, a plurality of liquid crystal optical elements of the present invention can be combined and driven individually, and can be used for a display device for displaying characters and figures. For example, by arranging a 10 cm square liquid crystal optical element to be 16 x 16 dots and displaying kanji, it is possible to make a large display device with one character more than 1 m, which was not possible with conventional liquid crystal display elements. Become.

In the liquid crystal optical element of the present invention, when a voltage is applied for driving, an AC voltage that changes the alignment of liquid crystals may be applied. Specifically, an AC voltage of 5 to 100 V and about 10 to 1000 Hz may be applied.

When no voltage is applied, the electrodes may be opened or short-circuited. Among them, the impedance between the electrodes, that is, the impedance of the electrodes, the connection impedance at the terminal portion, the total impedance of the circuit impedance, by lowering the impedance of the layer of the liquid crystal material and the cured product, 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 1/10 or less of the impedance of the layer of the liquid crystal substance and the cured product. Therefore, when the electrode impedance and the connection impedance at the terminals are high, it is preferable to lower the circuit impedance.

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

The element of the present invention is a display element, in particular, a conventional liquid crystal display element was difficult, large-area display element, in addition to being usable as a curved display element, a large-area dimming element, an optical shutter, etc. Many uses are possible.

Further, it can be installed in front of a light source such as a light bulb or the like, and can also be used, for example, for electrically switching between a fog lamp and a normal lamp.

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

In addition, color filters can be used in combination, or dichroic dyes can be mixed into the liquid crystal to produce a color, or laminated with other displays such as TN liquid crystal display devices, electrochromic display devices, and electroluminescent display devices. It may be used, and various applications are possible.

[Examples] Hereinafter, the present invention will be specifically described with reference to Examples.

Example 1 2 parts of n-butyl acrylate, 4 parts of 2-hydroxyethyl acrylate, 3 parts of acrylic oligomer ("M-6200" manufactured by Toagosei Co., Ltd.), and liquid crystal ("E-8" manufactured by BDH)
18 parts, a photo-curing initiator (“Darocur 111
6 ") 0.18 part was added and dissolved uniformly. 0.9 g of this solution,
In addition to 3.1 g of urethane latex (“Implanyl DLS” manufactured by Bayer Japan), a stable latex was prepared by diffusing with a diffusion device (“LK-21” manufactured by Yamato Scientific Co., Ltd.).

This latex was applied on a polyester substrate with ITO, and water was evaporated to form a semi-cured film-like liquid crystal layer having a film thickness of about 20 μm.

Next, as the other substrate, an ITO-attached polyester substrate is overlaid and an ultraviolet irradiation device (Toshiba
400 ") for about 5 spectral exposures to complete the cure.

The entire surface of this device was clouded in this state. When an alternating voltage of 50 Hz and 80 V was applied to this element, the entire surface became transparent.

In addition, after stacking the polyester substrate with ITO as the other substrate, a black tape with a T cut out was attached as a light-shielding mask, and an ultraviolet irradiation device was applied while applying an AC voltage of 50 Hz and 60 V to the entire cell. After about 1 spectral exposure, the mask was removed, and about 5 spectral exposure was performed by an ultraviolet irradiation device to complete curing.

In this state, a T-shaped transparent portion was formed in this state, and the other portion was opaque.

When an AC voltage of AC80V (50Hz) was applied to this element, the entire surface became transparent.

Example 2 18 parts of liquid crystal (“E-8” manufactured by BDH) was added to 1 part of n-butyl acrylate and 5 parts of 2-hydroxyethyl acrylate.
And 0.12 part of benzoin isopropyl ether as a photocuring initiator were added and uniformly dissolved. This solution was used in Example 1
A stable latex was prepared in the same manner as in.

This latex was applied on a polyester substrate with ITO, and water was evaporated to form a semi-cured film-like liquid crystal layer having a film thickness of about 20 μm.

Next, as the other substrate, an ITO-attached polyester substrate is overlaid and an ultraviolet irradiation device (Toshiba
400 ") for about 3 spectral exposures to complete the cure.

The entire surface of this device was clouded in this state. When an alternating voltage of 50 Hz and 80 V was applied to this element, the entire surface became transparent.

In addition, after stacking the polyester substrate with ITO as the other substrate, a black tape with a T cut out was attached as a light-shielding mask, and an ultraviolet irradiation device was applied while applying an AC voltage of 50 Hz and 60 V to the entire cell. After about 1 spectral exposure, the mask was removed, and about 3 spectral exposure was performed by an ultraviolet irradiation device to complete curing.

In this state, a T-shaped transparent portion was formed in this state, and the other portion was opaque.

When an AC voltage of AC80V (50Hz) was applied to this element, the entire surface became transparent.

Example 3 An element similar to that of Example 1 was used, and 2 elements were provided between the black light-shielding te
The sheet was sandwiched via a sheet of polyvinyl butyral and was heated and pressurized in an autoclave to be integrated.

The element integrated in this way was safe against external pressure and had high reliability.

Example 4 In the same manner as in Example 1, except that the black tape obtained by cutting out the letter T in Example 1 was used as a mask instead of the light-shielding mask, light exposure was performed, and then a voltage was applied. Without light exposure, a device was prepared.

When an AC voltage (AC80V, 50Hz) was applied to this device, the entire surface became transparent, and when the voltage was cut off, an image with a halftone from the transparent part to the clouded part was obtained.

Example 5 A device was manufactured in the same manner as in Example 1 except that the pattern of the person who was skiing was used as the mask pattern.

This element was provided in front of the show window where the ski equipment was placed. In this show window, the pattern of the person who is skiing is displayed cloudy when no voltage is applied, but the entire surface became transparent when an AC voltage (AC80V, 50Hz) was applied.

Example 6 A device was manufactured in the same manner as in Example 1 using a pattern having circular holes as a mask pattern.

This element was used as a dimmer and used for a door. When no voltage was applied to this door, the inside was visible only from the round hole, and when an AC voltage (AC80V, 50Hz) was applied to it, the entire surface became transparent. Thus, when the room inside the door is in use, the inside can be seen only through the round hole, and when not in use, the door is completely transparent and can be seen at a glance.

Example 7 A device was manufactured in the same manner as in Example 1 using a pattern having rectangular holes as a mask pattern.

This element was used as a dimmer and used as a glass door for a file shelf. When no voltage was applied to this glass door, the inside of the file shelf was visible only from the rectangular hole, and when the AC voltage (AC80V, 50Hz) was applied to it, the entire glass door became transparent.

As a result, the file number or the like that may be seen by others on the file placed on the file shelf is always visible, but the title of the file can be seen only when a voltage is applied.

Example 8 A device was manufactured in the same manner as in Example 1 except that a square mask whose periphery was hollowed out was used as a mask pattern.

A dot display type display device was prepared by making it possible to display one character with 8 × 8 elements.

In this display device, the area around each dot is always transparent, allowing light to pass through, but AC voltage (AC80V, 50Hz)
When you apply, only the applied dots become completely transparent,
The display was made.

[Effects of the Invention] As described above, the present invention provides a novel method for producing a liquid crystal optical element, in which the cured product obtained has a refractive index of
A curable compound selected to match either the ordinary refractive index (n _o ), extraordinary refractive index (n _e ) of the liquid crystal substance used, or the refractive index (n _x ) when the liquid crystal substance is randomly aligned. Using a latex mixed with a liquid crystal substance and a polymer substance, first evaporate water to cure the polymer,
A semi-cured film-like liquid crystal layer having a structure in which a dissolved mixture of a curable compound and a liquid crystal substance is filled in a void portion of a resin matrix of a polymer substance, and then the curable compound is cured to form a liquid crystal substance. It is an element with fixed phase separation from the cured product. Therefore, the present invention does not require a polarizing plate, is an element excellent in appearance quality and productivity, and an element having a large area and uniform performance can be easily obtained.

In the present invention, compared to simply obtaining a film-like liquid crystal layer using a solution obtained by mixing a liquid crystal substance and a curable compound that can be dissolved therein, even if it has a large area, it is easy to make the film thickness uniform,
Even a curved substrate can be easily dealt with.

Further, as compared with a case where a film-like liquid crystal layer is simply obtained by using a latex containing only a liquid crystal substance and a polymer substance, it is possible to pressurize and cure the substrate in a subsequent step, so that a uniform film thickness is easily obtained, and It has the advantages that a high curing rate such as light exposure can be obtained, the productivity is good, and the adhesiveness between the two substrates is also provided by itself. Furthermore, by partially curing while applying a voltage, a specific orientation can be partially formed and a fixed display can be easily obtained.

In particular, when a curable compound is cured, a voltage is applied between at least a part of the substrates to cause a specific orientation, thereby making it possible to display, particularly in a large area, a curved display, and a large area. It can be widely used for light control, optical shutter, etc.

In particular, it is possible to fix the phase separation between the liquid crystal substance and the cured product by holding it between a pair of substrates with electrodes, using the photocurable compound as the curable compound, and curing the photocurable compound by light exposure. It is preferable that the curing time is short, the productivity is extremely high, and a specific fixed display can be easily obtained only with a mask.

Further, there is also an advantage that the patterning using a mask of a specific pattern allows the specific part and the remaining part to be continuously cured by the same apparatus.

Further, specific characters and figures can be displayed without patterning the electrodes. In addition, it is possible to easily enclose characters, figures, graphs, etc. in a continuous frame, and there is an advantage that the degree of freedom in display and the ease of designing a display pattern are improved.

In addition, when light curing while applying a voltage near the threshold voltage, or when curing by light exposure for a short time while applying a voltage, light is not completely in the transmission state,
It is also possible to form a part where light is transmitted or is clouded more than the surrounding masked part. This makes it possible to display a halftone that is not binary, transparent or cloudy.

Further, by providing a protective plate on at least one surface of the substrate, safety is improved. In particular, by providing the protective plate on both surfaces, breakage is less likely to occur.

In particular, a latex mixed with a liquid crystal substance, a curable compound, and a polymer substance is supplied onto the substrate, the moisture is evaporated to cure the polymer substance, and the other substrate is placed on the latex to perform light exposure or exposure. By heating to cure the curable compound,
Uniform and large-area devices can be manufactured with extremely high productivity. Therefore, a considerably long substrate can be used even when the substrate is glass, and a continuous process using a continuous film is also possible when the substrate is plastic.

Especially when a plastic substrate is used as the substrate,
Although the productivity is good, the strength is inferior, so that when the area is increased, it is easily broken or curved. Therefore, the effect of providing the protective plates on both sides is great. Above all, by using a glass plate as a protective plate and adhering it with an adhesive material, a structure similar to that of laminated glass is obtained, and safety and reliability are enhanced.

In addition to the above, the present invention can be applied in various ways within a range that does not impair the effects of the present invention.

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Claims (3)

[Claims] 1. A method for producing a liquid crystal optical element, comprising a film-like liquid crystal layer having a liquid crystal substance filled in voids of a resin matrix and sandwiched between a pair of substrates with electrodes. The refractive index of an object matches either the ordinary refractive index (n _o ), extraordinary refractive index (n _e ) of the liquid crystal substance or the refractive index (n _x ) when the liquid crystal substance is randomly oriented. And a liquid crystal substance that is compatible with the curable compound, and a polymer substance selected so as to have a refractive index that matches the refractive index of the cured product of the curable compound, the latex with one electrode It is supplied to the above to evaporate water to form a semi-cured film-like liquid crystal layer in which a dissolved mixture of a liquid crystal substance and a curable compound is filled in a void portion of a matrix of a polymer substance, and the other electrode is formed thereon. Hardened by stacking attached substrates And fixing the phase separation between the cured product of the curable compound and the liquid crystal substance to form a film-like liquid crystal layer in which the liquid crystal substance is filled in the voids of the matrix of the polymer substance and the cured product. Liquid crystal optical element manufacturing method. 2. A voltage is applied to at least a portion of an electrode where a specific orientation state is desired to be applied, and a portion other than a portion where the specific orientation state is desired to be masked is exposed to light to be cured, and then the mask is removed. The method for producing a liquid crystal optical element according to claim 1, wherein the uncured portion is cured without applying a voltage. 3. A part desired to be kept in a specific alignment state is masked, and a part other than the part to be kept in a particular alignment state is exposed to light to be cured, and then the mask is removed to keep at least a particular alignment state. The method for producing a liquid crystal optical element according to claim 1, wherein the uncured portion is cured while applying a voltage to the electrode of the portion.