JPH07119920B2 - Liquid crystal optical element, method for manufacturing the same, light control body and display device using the same - Google Patents

Description

The present invention relates to a transmission / scattering type liquid crystal optical element, a method for manufacturing the same, and the use thereof.

[Prior Art] Recently, HG Craighead et al. Appl.Phys.Lett., 40 (1) 22 (1)
As disclosed in 982), a liquid crystal optical element in which a liquid crystal film in which a liquid crystal substance is dispersed in a matrix of a cured product of resin is sandwiched between a pair of substrates with electrodes by taking advantage of the refractive index anisotropy of liquid crystal is noted. Has been done. Specifically, a liquid crystal film in which a porous material is impregnated with a liquid crystal substance or a liquid crystal substance is encapsulated in microcapsules is used, and the refractive index of the liquid crystal is changed depending on the presence or absence of voltage application to form a matrix. The transmission and scattering are controlled by adjusting the refractive index of the porous body and the outer wall of the microcapsule.

This liquid crystal film is a principle DS without using a polarizing plate.
It is a useful method that can overcome the drawbacks of (dynamic scattering) mode and PC (phase transition) mode.

In addition to this, JL Fergason et al. Used a nematic liquid crystal film microencapsulated with polyvinyl alcohol (JP-A-58-501631), and KNPe
Arlman et al. use a liquid crystal film of various latex-loaded liquid crystals (Japanese Patent Laid-Open No. 60-252687), and JWDoane et al. use a liquid crystal film in which a liquid crystal is dispersed and cured in an epoxy resin (Japanese Patent Publication No. 61-502128). Creating.

[Problems to be Solved by the Invention] A liquid crystal optical element using a liquid crystal film produced by these methods shows a transmission-scattering state by a voltage applied between substrates with electrodes on both surfaces and dimming of light. And could be used for display.

That is, since these liquid crystal optical elements are formed almost uniformly over the entire surface, when a substrate having a solid electrode on the entire surface is used, the entire surface is in a scattering state at the same time due to voltage application, or conversely it is transmitted. It was in a state.

Therefore, in order to display some pattern, it is necessary to perform specific electrode patterning in advance or to provide some fixed display means.

However, if such electrode patterning is done,
There is a portion where the electrode does not exist, the transmission-scattering cannot be controlled in that portion, and it is sometimes difficult to design the arrangement of the electrode. Further, it was necessary to provide terminals for the number of electrodes.

It is also conceivable to use the electrode as a resistance electrode so that the voltage actually applied to the liquid crystal portion becomes lower than the voltage connected to the terminal as the distance from the terminal increases. But,
Such a configuration also has a problem that it cannot be used in applications such as bar graphs in which the number of sequentially lit segments is increased.

Therefore, the light transmission state is partially reduced by only changing the voltage.
A liquid crystal optical element that can be changed to the above different states has been desired.

[Means for Solving Problems] The present invention has been made to solve the above-mentioned problems, and the obtained cured product has a refractive index (n _o ) of the ordinary light of the liquid crystal substance to be used A film-like liquid crystal in which a liquid crystal substance is dispersed and held in a cured product matrix selected so as to match either the light refractive index (n _e ) or the refractive index (n _x ) when the liquid phase substance is randomly oriented. A liquid crystal optical element having a layer sandwiched between a pair of substrates with electrodes, wherein the film-like liquid crystal layer has a portion where the threshold voltages are different, and the liquid crystal optical element is partially A liquid crystal optical element, characterized in that it has a portion where the voltage at which the change in the transmittance of the film-like liquid crystal layer reaches saturation is different.
And a liquid crystal optical element characterized in that a protective plate is adhered to both sides of these elements with an adhesive material layer.

Further, in the method for producing a liquid crystal optical element, when curing a curable compound that is a raw material of a cured product, a method for producing a liquid crystal optical element, characterized in that the curing conditions are partially changed and cured, Further, the present invention provides a method for producing a liquid crystal optical element, which comprises partially curing a photocurable compound as a raw material of a cured product under different temperature conditions.

Furthermore, a liquid crystal optical element comprising these liquid crystal optical elements and a driving means for applying a voltage to the liquid crystal optical element, and a dimmer characterized by obtaining a transmission state of three or more lights by the applied voltage, and a plurality of the liquid crystal optical elements. It is an object of the present invention to provide a display device provided with a driving means capable of individually driving each combination.

Since the element of the present invention partially has a portion where the threshold voltage of the film-like liquid crystal layer or the voltage at which the change in the transmittance reaches saturation (saturation voltage) is different, it is only necessary to change the applied voltage. The light transmission state can be partially changed.

As a result, even if the electrodes of the substrate are all solidly formed over the entire surface, it is possible to obtain three types of light transmission states by only changing the voltage.

The liquid crystal substance is present in the cured product matrix selected so that the refractive index of the resulting cured product matches either the ordinary refractive index (n _o ) or the extraordinary refractive index (n _e ) of the liquid crystal substance used. A case where a film-shaped liquid crystal layer held in a dispersed state is used will be described as an example.

In this case, when the threshold voltage is partially changed, the film-like liquid crystal layer is in a scattering state when the voltage is not changed. Therefore, when voltage is applied, half of the element gradually starts to transmit light, and when viewed at the _first voltage V ₁ , half of the element transmits light to some extent,
The other half is scattered. When the voltage is further increased, the other half of the light also starts to be transmitted, and when viewed at a sufficiently high second voltage V ₂ (V ₁ <V ₂ ), the entire surface of the element is in a transmissive state.

Therefore, no voltage is applied, the first voltage V _{1 is} applied, and the second voltage V _{2 is} applied.
By the three states of application, it is possible to set three kinds of light transmission states (full scattering, half transmission, half scattering, full transmission) for one element.

Further, when the saturation voltage is partially changed, the film-like liquid crystal layer is still in the scattering state in the state where the voltage is not changed. Therefore, when voltage is applied, if the threshold voltage is the same, light gradually starts to pass through the element, and when viewed at the _first voltage V ₁ , half of the element receives a considerable amount of light. The light is transmitted, but the other half is in a state where light is transmitted at a lower transmittance than that. In this case, the first voltage
If V ₁ is higher than the saturation voltage of _one side, one side will be completely transparent to light. When the voltage is further increased, the second voltage V ₂ (V ₁ <V ₂ ) causes the entire surface of the device to have almost the same transmission state. Also in this case, if the second voltage V ₂ is higher than both saturation voltages, the entire light is completely transmitted.

Therefore, no voltage is applied, the first voltage V _{1 is} applied, and the second voltage V _{2 is} applied.
By the three states of application, it is possible to set three kinds of light transmission states (full scattering, half transmission, half scattering, full transmission) for one element.

Accordingly, by partially changing the threshold voltage or the saturation voltage of the film-like liquid crystal layer, it is possible to express a specific pattern such as a pattern, a character, or a figure only by changing the applied voltage.

Specifically, applying this to a door, for example, when no voltage is applied during a meeting, the inside is invisible due to full-scale scattering, and if there is a knock, part of it becomes transparent and the person confirms it. There is a usage method in which it can be seen that the entire surface is transparent and unused when the room is empty after the meeting.

Also, by applying this to the window, the threshold voltage or saturation voltage of the film-like liquid crystal layer is changed only at the part such as the mark of the company to make the window completely transparent or opaque, and Only parts can be transparent or opaque.

In the above description, an example in which either the threshold voltage or the saturation voltage of the film-like liquid crystal layer is different has been described, but both the threshold voltage and the saturation voltage are changed,
It is also possible to set a threshold voltage or a saturation voltage of 3 or more to increase the number of changes in the transmission state.

The present invention makes great use of such characteristics when used in a light control body.

The liquid crystal element of the present invention, the refractive index of the resulting cured product, by keeping the refractive index of the liquid crystal material used to match the n _o or n _e, if no voltage is applied, which is not arranged Due to the difference in the refractive index between the substance and the cured product, it shows a scattering state (that is, a cloudy state), and when a voltage is applied, the liquid crystal substance is aligned and the refractive index of the liquid crystal (n _o or n _e )
And the cured product obtained by photocuring are in agreement with the refractive index to show a transmissive state, and can be said to be an excellent element having a reversible dimming function.

This device partially forms a part where the threshold voltage or the saturation voltage of the film-like liquid crystal layer is different by changing the hardening condition of only a specific part during the curing step for forming the film-like liquid crystal layer. it can. In addition to this, even if the substrate gap is partially changed, a part where the threshold voltage or the saturation voltage of the film-like liquid crystal layer is different can be partially formed, but the light transmittance at the time of scattering is considerably different. Therefore, it is preferable that the substrate gap is the same and the curing conditions are changed as described above.

The difference in the curing conditions for forming the part where the threshold voltage or the saturation voltage of the film-like liquid crystal layer is partially different is, for example, temperature and light. Therefore, it can be easily obtained by using a photocurable compound as a raw material of a cured product and changing the temperature at the time of curing by light exposure for curing.

Specifically, since it is difficult to make a temperature difference at the boundary line when the temperature is partially changed and exposed to light at the same time, a mask is used to keep the whole at a certain temperature T ₁ , and the mask is exposed to light. The non-cured portion may be cured by curing the non-cured portion, then removing the mask to keep the whole at another temperature T ₂ , and irradiating again to cure the previously masked and uncured portion.

These curing conditions may be experimentally determined depending on the purpose, materials used, and the like.

Further, in the device of the present invention, the refractive index of the cured product cured by light exposure may be made to match the refractive index (n _x ) when the liquid crystal substance used is randomly aligned. Random alignment here means that not all liquid crystal molecules are aligned in parallel or perpendicular to the substrate surface, but oriented in various directions due to the influence of the mesh or capsules forming 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 cured product have the same refractive index, and thus shows a transmissive state. Conversely, when a voltage is applied, the liquid crystal material is aligned, the refractive index of the liquid crystal (n _o or n _e) and the refractive index of the cured product obtained by photocuring and will no longer match, scattering state (i.e. (White turbid state).

As a result, a transparent element can be obtained without applying a voltage. However, the cured product obtained by photocuring exists in the form of a mesh or capsule, and the liquid crystal is randomly oriented under the influence of this cured product. Since it is in the same situation as above, there is a problem that it is difficult to obtain a uniform state. this is,
When oriented vertically or horizontally like the former, it is easy to orient uniformly, but randomly oriented is slightly macroscopically random, but partially delicately aligned. This is because a difference in refractive index is generated, which is uneven and is easy to see.

In the present invention, the refractive index of the cured product and the refractive index of the liquid crystal substance to be used (any of n _o , n _e , and n _x ) are made to coincide, but this coincidence is made completely. However, it is preferable that they are substantially coincident with each other so that the transmission state is not adversely affected. In particular,
It is preferable that the difference in refractive index is about 0.15 or less.
This is because the cured product swells due to the liquid crystal substance and becomes closer to the refractive index of the liquid crystal substance than the original refractive index of the cured product. Become.

In the present invention, it is preferable that a light transmissive compound is used and photocured to form a matrix of a cured product.

This makes it possible to easily form a film-like liquid crystal layer having a different threshold voltage or saturation voltage at a desired portion. That is, by arranging a mask that blocks light on the surface of the substrate and changing the curing temperature, it is possible to easily change the curing condition of only a specific portion and cure it, and change the threshold voltage or saturation voltage of that portion. 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 may be any of vinyl polymerization, addition polymerization, condensation polymerization, cationic polymerization, anionic polymerization, living polymerization, etc., but substances that may deteriorate liquid crystal substances such as water and corrosive substances. Condensation polymerization to generate is generally unfavorable.

The polymerization system may be either homogeneous or heterogeneous. For example, it may be a mixture of a photocurable compound and liquid crystal, or may be a microcapsule obtained by mixing the photocurable compound and liquid crystal with ponyvinyl alcohol or the like.

Specific examples of the photocurable compound include monoacrylate, diacrylate, N-substituted acrylamide, and N.
-Represented by vinylpyrrolidone, styrene and their derivatives, polyol acrylate, polyester acrylate, urethane acrylate, epoxy acrylate, silicone acrylate, fluoroalkyl acrylate, polybutadiene skeleton, acrylate having isocyanuric acid skeleton or hydantoin skeleton, unsaturated cycloacetal, etc. Compounds having monofunctional and polyfunctional vinyl groups are exemplified.

In the present invention, it is preferable to use these various photocurable vinyl compounds. Above all, it is preferable to use an acryloyl compound because the phase separation state of the liquid crystal and the cured product after photoexposure and its uniformity are excellent, and the curing speed by photoexposure is fast and the cured product is stable. . The acryloyl group of the acryloyl compound referred to here is α
The hydrogen at position β, is phenyl, alkyl, halogen,
It may be substituted with cyano or the like.

In the present invention, among these photo-curable vinyl compounds, those that are polymerized and cured by irradiation with light, especially those that contain an oligomer that polymerizes and polymerize, are preferable.

Specifically, it is preferable to contain 15 to 70 wt% of an acrylic oligomer containing two or more vinyl groups as a photocurable vinyl compound, and the shrinkage caused by curing after photocuring is small and minute cracks in the liquid crystal optical element. Is less likely to occur, and the moldability is good. If the number of the minute cracks increases, the light transmittance in the light transmitting state tends to decrease, and the device performance decreases. If the viscosity of this acrylic oligomer is too high or too low, it adversely affects the moldability.
It is preferably about 0-500000 cps.

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

Further, the liquid crystal substance used is preferably uniformly dissolved in the curable compound, and it is necessary that the liquid crystal substance does not dissolve or is difficult to dissolve in the matrix of the cured product after curing, and when the composition is used, It is desirable that the solubility of each liquid crystal substance be as close as possible.

In particular, a liquid crystal substance and a photo-curable compound are used, and the liquid crystal substance and the cured product are fixed by phase separation by a photo-curing process, resulting in a structure in which the liquid crystal substance is scattered in the matrix of the cured product. As a result, the distribution of the cured product becomes uniform, and an element with excellent appearance quality and productivity can be easily manufactured.

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

In addition, the mixture of the curable compound and the liquid crystal substance for forming the film-like liquid crystal layer may be used alone or in combination with the curable compound and the liquid crystal substance. It may contain a modifier for the element. Specifically, a crosslinking agent, a surfactant, a diluent, a thickener, a defoaming agent, an adhesiveness-imparting agent, a stabilizer, an absorbent, a dye, a polymerization accelerator, a chain transfer agent, a polymerization inhibitor, a pigment, It may contain a dye or the like.

When manufacturing the device of the present invention, the mixture of the curable compound and the liquid crystal substance to be prepared may be liquid or viscous as long as they are uniformly mixed. You can choose. For example, it is generally convenient to inject it in a liquid state into a cell in which glass substrates with transparent electrodes such as In ₂ O ₃ -SnO ₂ and SnO ₂ are arranged so as to face each other and the periphery is sealed. When it is applied to a substrate such as an attached plastic or glass and the opposite substrates are to be superposed, the viscous state is generally more convenient.

The substrate-to-substrate gap can operate at 5 to 100 μm, but it is suitable to set it to 7 to 40 μm in consideration of the applied voltage and the contrast at the time of on / off.

In this way, the mixture held on the substrate is cured.
In this case, it is preferable to use a photocurable compound and to fix the liquid crystal substance and the cured product in a phase-separated state by light exposure. In the case where the refractive index of the cured product matches the n _o or n _e of the liquid crystal material before the light exposure, if the contents held by the substrate if uniformly dissolved, it is colorless and transparent, light exposure After that, the liquid crystal substance that is not aligned and the cured product become a white turbid state due to the refractive index scattering. The element of the present invention thus created, by applying a voltage equal to or higher than the threshold value, the liquid crystal substance begins to be aligned, and the transmittance increases because the refractive index is close to that of the cured product,
By applying a voltage equal to or higher than the saturation voltage, the refractive index of the cured product matches that of the cured product, resulting in a high transmission state.

Further, when the refractive index of the cured product is matched with the refractive index (n _x ) of the liquid crystal substance, the contents held on the substrate are colorless and transparent before light exposure if they are uniformly dissolved. After the photoexposure, the liquid crystal substance that is not aligned and the cured product have the same refractive index, so that they are in a transmissive state. In the element of the present invention thus produced, when a voltage is applied, the liquid crystal substance is aligned, and the refractive index shifts from that of the cured product to scatter, resulting in a cloudy state.

In the present invention, the threshold voltage or the saturation voltage of the film-like liquid crystal layer is changed by partially changing the curing conditions during the curing.

In order to change this curing condition, it is easy to manufacture by changing the temperature at the time of curing by using a photocurable compound, and
The threshold voltage or the saturation voltage can be easily changed. The specific method is as follows.

A light-shielding mask is formed on a specific part, and while maintaining a certain temperature, light is applied to cure the part excluding the specific part, then the light-shielding mask is removed and the temperature is changed,
Cure the rest.

While maintaining a certain temperature, a specific portion is scanned and cured with a laser or the like, and the remaining portion is scanned with a laser or the like or the whole is irradiated with light to be cured.

Further, these methods may be combined, or the temperature may be changed in three or more steps to cure each.

In the present invention, a dichroic dye or a simple dye or pigment is added to the liquid crystal, a colored curable compound is used, a colored substrate is used as a substrate, or a color filter is laminated. You can also add a specific color.

By using a liquid crystal substance as a solvent and curing the photocurable compound by light exposure, it is not necessary to evaporate a simple solvent or water that is unnecessary at the time of curing, so that it can be cured in a closed system and has high reliability, and Since it also has the effect of adhering two substrates with a photocurable compound, it is possible to eliminate the need for a sealant.

Therefore, a solution of the photocurable compound and the liquid crystal substance is supplied onto one of the electrode-attached substrates, the other electrode-attached substrate is further superposed thereon, and then the product is irradiated with light to be cured. A good manufacturing method can be adopted.

In particular, by using a plastic substrate as the electrode-attached substrate, a long liquid crystal optical element using a continuous plastic film can be easily manufactured.

By using a liquid crystal composed of such a liquid crystal and a matrix of a curable compound, the risk of short circuit 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 addition, in order to reduce unevenness of the light transmission state, it is preferable that the substrate gap be constant to some extent. Therefore, it is preferable to dispose a spacer for controlling the gap, such as glass particles, plastic particles, or ceramic particles, in the gap between the substrates. Specifically, a mixture of a photocurable compound and a liquid crystal substance is supplied on a substrate while containing a spacer for controlling a substrate gap, or a spacer is supplied before or after the mixture and the other substrate is superposed. Just do it. In this case, apply pressure after stacking,
After that, by curing, a more uniform substrate gap is likely to be formed.

Such a liquid crystal optical element can be used as a display element, but is suitable for use as a light control body because it can be easily made large in area and can be cut later into a desired size. . When used as a dimmer,
Since it is usually a transmissive type, the electrode is a transparent electrode. 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 is further laminated for protection, or the substrate is tempered glass, laminated glass,
Various applications are possible, such as cotton-filled glass.

In particular, a plastic substrate is used as a substrate with electrodes to form a liquid crystal optical element, an electrode lead-out line is attached, and an adhesive material layer such as polyvinyl butyral is interposed between two glass plates slightly larger than the liquid crystal optical element. It is preferable that the liquid crystal optical element and the glass plate are integrated with each other to form a laminated glass by hardening the adhesive material layer by sandwiching it and heating or irradiation with light. Above all, by using polyvinyl butyral as the adhesive material, a structure very similar to that of 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 applications of the dimmer using this liquid crystal optical element include building materials such as windows, skylights, partitions and doors, vehicle materials such as windows and moon roofs, cases, doors, lids and other materials for various electric products. It can be used.

When used as a dimmer, this liquid crystal optical element
It suffices to add drive means capable of applying two or more types of voltages for driving this. As this driving means, one that can apply an alternating voltage of about several tens of V by switching the voltage is used as described later.

Further, this dimmer can be used in combination with an arrangement means for arranging various objects, and can be used for an object exhibit such as a show window or a showcase displaying various products.

Further, a plurality of liquid crystal optical elements of the present invention can be combined and each can be individually driven by a driving means capable of applying two or more kinds of voltages, and can be used in a display device for displaying characters and figures. For example, by arranging 10 cm square liquid crystal optical elements so as to form 16 x 16 dots and displaying Chinese characters, it is possible to use a large-sized display device with 1 m or more per character, which is 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, it is sufficient to switch and apply two or more voltages that are AC voltages of 5 to 100 V and about 10 to 1000 Hz, and that change the light transmission state of the element.

In addition, when no voltage is applied, it is usually sufficient to open or short-circuit the electrodes, but a voltage below the threshold value may be applied.

Also, the transmittance may be changed by applying voltages of three different levels.

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 so that it can be used, for example, for electrically switching 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, it is used in combination with a color filter or mixed with dichroic dye or pigment in the liquid crystal for colorization, or laminated with other displays such as TN liquid crystal display element, electrochromic display element, electroluminescence display element, etc. It may be used as it is, and various applications are possible.

[Function] For example, by using the photo-curable compound by the above-mentioned method, the temperature is changed to T ₁ , T ₂ and ₃ (T ₁ <T ₂ <T ₃ ), and the film-shaped liquid crystal layer is exposed by light exposure. When cured, the relationship between the applied voltage and the light transmittance when a voltage is applied to the liquid crystal optical element thus manufactured is as shown in FIG. 1, for example.

As is apparent from FIG. 1, the film-like liquid crystal layer obtained by changing the temperature at the time of light exposure has a threshold voltage Vt ₁ as the temperature changes to T ₁ , T ₂ and T ₃ . The saturation voltage changes in sequence to Vt ₂ , Vt _3, and the saturation voltage changes to Vs ₁ , Vs ₂ , Vs ₃ .

Therefore, V ₀ <V ₁ <V ₂ <V ₃ and V ₀ <Vs ₁ and Vt ₁ <V ₁ <
It suffices to drive at a voltage of Vs ₁ , Vt ₂ <V ₂ <Vs ₂ , Vt ₃ <V ₃ . It should be noted that V ₀ may be a short circuit without applying a normal voltage. Also, V ₃ should normally be set to the same level as Vs ₃ or higher.

However, the amount of change in the threshold voltage and the amount of change in the saturation voltage differ depending on the raw material of the cured material used, the liquid crystal substance, the additive, etc., and some change to the same extent as shown in FIG. Some change only or the amount of change is different. For this reason, the curing conditions may be experimentally determined depending on the system used for curing, and the drive voltage may be set.

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

Example 1 2 parts of acrylic photopolymerizable resin, liquid crystal (BDH [E-
8 ") and 0.04 part of a photo-curing initiator (" Darocur 1116 "manufactured by Merck & Co., Inc.) are uniformly dissolved, and a mixture of 0.01 parts of a 20 µm spacer is cast onto a polyethylene terephthalate film with ITO. , And an ITO-attached polyethylene terephthalate film was laminated on it.

This was cured by light exposure for 2 minutes at a temperature of 20 ° C. and 35 ° C. using an ultraviolet irradiation device. All of the thus obtained devices were in a totally scattering state when no voltage was applied, and became transparent when a voltage of 50 Hz and 100 V was applied.

When the threshold voltage and the saturation voltage of these two types of elements were examined, the threshold voltage and the saturation voltage at the curing temperature of 20 ° C were 2V and 28V, respectively, and the threshold voltage at the curing temperature of 35 ° C. The voltage and saturation voltage were 22V and 74V, respectively.

Therefore, the same mixture was sandwiched between polyethylene terephthalate films with ITO, a "A" -shaped mask was placed on the surface, and the mask was removed by photoexposure for 2 minutes at 20 ° C with an ultraviolet irradiation device. The temperature was raised to ° C and the exposure was performed again by an ultraviolet irradiation device.

This element is in a total scattering state when no voltage is applied, and when a voltage of 50Hz, 20V is applied, only the character pattern of "A" is in a scattering state, and the surroundings are in a state where almost light is transmitted, When a voltage of 50 Hz and 100 V was applied, the entire surface became transparent.

Example 2 1 part acrylic photopolymerizable resin, liquid crystal (“RO
2 parts of TN4931 ") and 0.05 part of benzoin isopropyl ether as a photo-curing initiator were uniformly dissolved, and the mixture was injected into a glass substrate cell with ITO having a substrate gap of 25 μm, and the injection port was sealed.

This was exposed to light for 1 minute by an ultraviolet irradiation device at a temperature of 20 ° C. and 35 ° C. to be cured. All of the thus obtained devices were in a totally scattering state when no voltage was applied, and became transparent when a voltage of 50 Hz and 100 V was applied.

When the threshold voltage and the saturation voltage of these two types of elements were examined, the threshold voltage and the saturation voltage at the curing temperature of 20 ° C were 0.5 V and 26 V, respectively, and the threshold at the curing temperature of 30 ° C. The value voltage and the saturation voltage were 3V and 52V, respectively.

Therefore, using the same unexposed cell, place an "A" -shaped mask on the surface, and use an ultraviolet irradiation device at 1
After exposure to light for a minute, the mask was removed, the temperature was lowered to 20 ° C., and exposure was performed again using an ultraviolet irradiation device.

This element is in a total scattering state when no voltage is applied, and when a voltage of 50Hz, 15V is applied, the scattering state of the character pattern of "A" is weaker than the surrounding area and the transmittance is high, 50Hz, 100V When a voltage of 2 was applied, the entire surface became transparent.

Example 3 When the device used in Example 1 was cured at 28 ° C., the threshold voltage and the saturation voltage were 12V and 42V, respectively.

Four circular masks were arranged on the substrate of the unexposed device of Example 1 in the same manner as 4 of the dice, and while being kept at 20 ° C., light exposure was performed for 2 minutes by an ultraviolet irradiation device, and then four circular masks were used. Of the above masks, the upper two masks were removed, the temperature was raised to 28 ° C and the exposure was performed again, and the remaining lower two masks were removed and the temperature was raised to 35 ° C and the exposure was performed again. .

This element is in a total scattering state when no voltage is applied. When a voltage of 50 Hz and 10 V is applied, four circular patterns of the same shape as those used in the mask are in a scattering state, and other portions are It became translucent. Also, 50Hz, 40V
When a voltage of 2 was applied, only the lower two circular patterns were in a slightly weak scattering state, and the other portions were in a transparent state. When a voltage of 50 Hz and 100 V was further applied, the entire surface became transparent.

In this example, no voltage is applied and three types of voltage are applied,
It was possible to take four types of transmission states.

Examples 4 and 5 The devices produced in Examples 1 and 3 were sandwiched between two glass plates with two polyvinyl butyral films interposed therebetween,
It was heated and pressurized in the autoclave to be integrated.

The element thus integrated was safe against external pressure and highly reliable.

Example 6 A device was manufactured in the same manner as in Example 1 using the pattern of the person image of skiing as the mask pattern.

This element was provided as a light control device in front of the show window in which the ski equipment was placed. This show window is invisible in a scattered state when no voltage is applied,
When a voltage of 20 V is applied, only the pattern of the person skiing is displayed in a scattered state, the surroundings are almost in the state of transmitting light, and the inside of the show window can be seen,
When a voltage of 50 Hz and 100 V was applied, the entire display became transparent and the show window was visible.

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

This device was used as a dimmer and was used for a door. When no voltage was applied to this door, the entire surface was scattered and the inside could not be seen. When a voltage of 50 Hz and 20 V was applied, the inside was visible only from the round hole portion, and when a voltage of 50 Hz and 100 V was applied, the entire surface of the door was transparent and the inside was visible.

As a result, the inside of the door cannot be seen while using the room, and only the round hole becomes transparent if necessary.
When not in use, the door is completely transparent and can be seen at a glance.

Example 8 A device was manufactured in the same manner as in Example 1 except that a square mask smaller than the substrate 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, when a voltage of 50 Hz and 20 V is applied, only the square at the center of each dot becomes transparent, and when a voltage of 50 Hz and 100 V is applied, the entire dot becomes transparent and It was displayed that the amount of transmitted light changed.

[Effects of the Invention] As described above, the present invention provides a novel liquid crystal optical element and a method for producing the same, and the refractive index of the obtained cured product is the ordinary refractive index (n _o ) of the liquid crystal substance used. , A film-like liquid crystal in which a liquid crystal substance is dispersed and retained in a cured product matrix selected so as to match either the extraordinary light refractive index (n _e ) or the refractive index (n _x ) when the liquid crystal substance is randomly aligned. A liquid crystal optical element in which a layer is sandwiched between a pair of electrode-attached substrates, and a film-like liquid crystal layer is provided with a part where the threshold voltage and / or the saturation voltage are different from each other, thereby providing a conventional liquid crystal optical element. While maintaining the same effect as the element, it is possible to reveal not only the entire surface scattering and the entire surface transmission but also a specific pattern without patterning the electrodes.

In the present invention, by using a mixture of a curable compound and a liquid crystal substance and fixing the phase separation to form a film-like liquid crystal layer, the productivity is excellent and a large liquid crystal optical element can be easily manufactured. . In particular, when a photocurable compound is used as the curable compound and the curing is performed by photoexposure, the threshold voltage or the saturation voltage can be easily partially changed by changing the temperature and curing. Further, since it is photocured, the curing time is short and the productivity is extremely high.

Further, the liquid crystal optical element can be manufactured basically by the same method as the conventional method for manufacturing a liquid crystal optical element, only a few steps are added, and the productivity is hardly reduced.

Further, by patterning using a mask having a specific pattern, there is an advantage that curing of this specific portion and curing of the remaining portion can be continuously performed in the same apparatus by only changing the temperature.

Further, two states of full surface scattering and full surface transmission are possible, and 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 the present invention, by using the photocurable vinyl compound, the device has high reliability, has a laminated glass-like structure, is less likely to be damaged by external pressure, and has high safety.

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

In particular, by supplying a liquid crystal substance on the substrate, a photocurable compound, particularly a photocurable vinyl compound, and further, if necessary, a mixture with a photocuring initiator, and placing the other substrate on it, Large-area devices can be manufactured with extremely high productivity.
Therefore, a considerably long substrate can be used even in the case of glass, and a continuous process using a continuous film is also possible in the case of a plastic substrate.

In particular, when a plastic substrate is used as the substrate, the productivity is good, but the strength is inferior. Therefore, when the area is increased, the substrate 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.

Further, in the liquid crystal optical element of the present invention, by using the photocurable vinyl compound, the liquid crystal substance and the cured vinyl compound form a fine three-dimensional network matrix,
Since the liquid crystal substance is dispersed, the device can be used after being cut into a desired size.

In this case, since the liquid crystal dispersions are connected to each other in the matrix, the liquid crystal is more likely to be uniformly aligned when a voltage is applied, and therefore, in a transparent state as compared with an element composed of microcapsules or independent liquid crystal grains. The haze is small and the driving voltage is low. It also has an effect of preventing the element from becoming reddish in the cloudy state.

INDUSTRIAL APPLICABILITY The liquid crystal optical element of the present invention is an element excellent in appearance quality and productivity, and can be widely used for display in a large area and a curved shape, and for light control in a large area, an optical shutter, and the like.

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.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the applied voltage and the light transmittance when a voltage is applied to an example of the liquid crystal optical element of the present invention. Threshold voltage: Vt ₁ , Vt ₂ , Vt ₃ Saturation voltage: Vs ₁ , Vs ₂ , Vs ₃

Claims (7)

[Claims] 1. The refractive index of the obtained cured product is the ordinary refractive index (n _o ) of the liquid crystal substance, the extraordinary refractive index (n _e ), or the refractive index when the liquid phase substance is randomly oriented ( n _x ), a liquid crystal optical element comprising a film-like liquid crystal layer in which a liquid crystal substance is dispersed and held in a cured product matrix selected so as to correspond to any one of a pair of substrates with electrodes,
A liquid crystal optical element, characterized in that the film-like liquid crystal layer partially has a portion having a different threshold voltage. 2. The refractive index of the obtained cured product is the ordinary refractive index (n _o ) of the liquid crystal substance used, the extraordinary light refractive index (n _e ), or the refractive index (n when the liquid crystal substance is randomly oriented). _x ), a liquid crystal optical element comprising a film-like liquid crystal layer in which a liquid crystal substance is dispersed and held in a cured product matrix selected so as to correspond to any one of a pair of substrates with electrodes,
A liquid crystal optical element, characterized in that the film-like liquid crystal layer partially has a portion where the voltage at which the change in the transmittance reaches saturation is different. 3. A liquid crystal optical element, characterized in that a protective plate is adhered to both surfaces of the liquid crystal optical element according to claim 1 or 2 with an adhesive material layer. 4. The method for producing a liquid crystal optical element according to claim 1 or 2, wherein when the curable compound which is a raw material of the cured product is cured, the curing conditions are partially changed and cured. A method for manufacturing a liquid crystal optical element. 5. The liquid crystal optical element according to claim 1 or 2, wherein the photocurable compound which is a raw material of the cured product is cured under partially different temperature conditions. Manufacturing method. 6. A light control body comprising the liquid crystal optical element according to claim 1, 2 or 3 and a driving means for applying a voltage to the liquid crystal optical element, and obtains a transmissive state of three or more lights by the applied voltage. 7. A display device comprising a combination of a plurality of liquid crystal optical elements according to claim 1, 2 or 3 and driving means capable of individually driving each of them.