JPH116988A - Temperature sensitive liquid crystal light modulating element and automatic temperature control system used it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the new temperature sensitive liquid crystal light modulating element and the automatic temperature control system used it automatically executing a light modulating operation in accordance with the variation of temperature. SOLUTION: The liquid crystal light modulating element 39 is composed by pinching a high polymer distributed liquid crystal 37 between a pair of glass substrates 31, 31 provided a transparent electrode 33. When respective solubility parameters of an oligomer material and monomer material forming a high polymer matrix 35 are described with (SP) olig, (SP) mono and the solubility parameter of a liquid crystal material is described with (SP) LC, the high polymer distributed liquid crystal 37 is composed of respective materials satisfying the relation of (SP) olig > (SP) LC + 2 or (SP) olig < (SP) LC - 2...(1) and moreover satisfying the relation of (SP) mono > (SP) LC + 2 or (SP) mono < (SP) LC - 2...(2).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a temperature-sensitive
A temperature-sensitive liquid crystal light control device comprising a liquid crystal having a characteristic of changing from one of a cloudy state and a transparent state to another state, and performing a light control operation by the characteristics of the liquid crystal, and the light control device The present invention relates to an automatic temperature control system that uses an automatic temperature control.

[0002]

2. Description of the Related Art A conventional light control device such as a light control glass window using a liquid crystal detects a temperature change in a room by a sensor.
The dimming operation is performed automatically by controlling the driving voltage of the liquid crystal based on the detection result, or simply by artificially adjusting the driving voltage of the liquid crystal. Therefore, there has been a demand for a light control element that automatically performs a light control operation in response to a temperature change without using a sensor or the like.

On the other hand, in recent years, research and development for applying a polymer dispersed liquid crystal (PDLC) in which a nematic liquid crystal is dispersed and held in a polymer having a refractive index substantially equal to the refractive index of liquid crystal molecules to a device has been actively carried out. Have been done. In particular, in view of the above-mentioned demands, developments have been made to realize a liquid crystal light control device that uses a polymer-dispersed liquid crystal and performs a light control operation automatically in response to a temperature change. Is being done.

Referring now to FIG. 11, a description will be given of a display principle of a polymer-dispersed liquid crystal, which is a basis when the polymer-dispersed liquid crystal is applied to a light control device. In the state where no voltage is applied, FIG.
As shown in FIG. 1A, since the molecular axis of the liquid crystal 24 is oriented in a random direction, the refractive index of the liquid crystal region is different from that of the surrounding polymer matrix 25, and the incident light 2
2 becomes scattered light 23, and as a result, a scattered state (white turbid state) is obtained. On the other hand, when an electric field equal to or more than the threshold is applied to the transparent electrode layer 21, the molecular axes of the liquid crystal 24 are arranged in the direction of the electric field as shown in FIG. Since the refractive index of the liquid crystal region substantially matches the refractive index of the surrounding polymer matrix 25, the light is not scattered and becomes the transmitted light 26. As a result, a transparent state is obtained.

Therefore, in order to realize a dimming device that automatically performs dimming operation in response to a change in temperature by using a polymer dispersed liquid crystal having such a display operation, it is necessary to change from a cloudy state to a transparent state. It is understood that a polymer-dispersed liquid crystal having a characteristic in which a voltage value that changes from a transparent state (or a transparent state to a cloudy state) changes in response to a temperature change may be manufactured. In other words, it is only necessary to control the temperature dependency of the polymer-dispersed liquid crystal.

[0006]

Considering the temperature dependence of the polymer dispersed liquid crystal, the temperature dependence of the polymer dispersed liquid crystal has a correlation with the Tg point (glass transition temperature) of the polymer material. (See, for example, the 19th Symposium on Liquid Crystal Chemistry, Proceedings, p. 48). From this viewpoint, the temperature dependence is determined by the thermal kinetics of the polymer material, especially the liquid crystal / polymer interface. Is considered to be involved in thermal movements in Therefore, in order to control the temperature dependence of the polymer-dispersed liquid crystal, it is important to control the interface regulating force acting between the liquid crystal and the polymer.

Unfortunately, however, it is difficult to freely control the interfacial regulating force, and there is still no specific concrete measure for improving the temperature dependence of the scattering-transmission characteristics of the polymer-dispersed liquid crystal. Is the current situation. Therefore, at present, there is no liquid crystal light control device that uses a polymer-dispersed liquid crystal and performs a light control operation automatically in response to a temperature change.

The present invention has been made in view of the above-mentioned problems, and controls the temperature dependence of the scattering-transmission characteristics of a polymer-dispersed liquid crystal. A novel temperature-sensitive liquid crystal light control device that obtains a polymer-dispersed liquid crystal having a characteristic of changing from one state to the other and performs a light control operation based on the characteristics of the liquid crystal, and an automatic light control device using the same. It is an object to provide a temperature control system.

[0009]

Means for Solving the Problems The present inventor paid attention to the solubility (compatibility) of a liquid crystal material and a polymer material used for forming a polymer-dispersed liquid crystal, and as a result of conducting many experiments, the polymer was It has been found that the temperature dependence of the scattering-transmission characteristics of the dispersed liquid crystal strongly depends on the solubility (compatibility) of the liquid crystal material and the polymer material or the wetting characteristics between the liquid crystal material and the polymer compound. Using a polymer-dispersed liquid crystal having such characteristics, a liquid crystal light control device that automatically performs light control in response to a temperature change having the following configuration and an automatic temperature control system using the same have been completed. .

In the liquid crystal light control device according to the first aspect of the present invention, a liquid crystal is sandwiched between a pair of glass substrates provided with electrodes, and the liquid crystal changes between a cloudy state and a transparent state in response to temperature. A temperature-sensitive liquid crystal dimming element having a characteristic of changing from one of the states to the other, and performing a dimming operation by the characteristics of the liquid crystal, wherein the liquid crystal is contained in a polymer matrix. It is a polymer-dispersed liquid crystal in which liquid crystal droplets are dispersed and held, and the solubility parameters of the oligomer material and the monomer material forming the polymer matrix are set to (S
When P) olig and (SP) mono are described, and the solubility parameter of the liquid crystal material is described as (SP) LC,
(SP) olig and (SP) LC satisfy the following expression (1): (SP) olig> (SP) LC + 2 or (SP) olig <(SP) LC-2 (1), and (SP) mono and (SP) LC satisfy the following expression (2): (SP) mono> (SP) LC + 2 or (SP) mono <(SP) LC-2 (2) And

According to the above configuration, by satisfying the relations of the expressions (1) and (2), the compatibility between the liquid crystal material and the polymer material is poor, and the interaction at the liquid crystal / polymer interface is small. Become. As a result, the liquid crystal molecules in the liquid crystal droplets of the polymer-dispersed liquid crystal are easily affected by the thermal mobility of the polymer matrix, and a polymer-dispersed liquid crystal having large temperature dependence of scattering-transmission characteristics can be obtained. Therefore, in a dimming device using such a polymer dispersed liquid crystal, it is possible to automatically perform a dimming operation in response to a temperature change.

According to a second aspect of the present invention, there is provided a liquid crystal light control device, wherein a liquid crystal is sandwiched between a pair of glass substrates provided with electrodes, and the liquid crystal is in a white turbid state and a transparent state in response to temperature. A temperature-sensitive liquid crystal dimming element having a characteristic of changing from one of the states to the other, and performing a dimming operation by the characteristics of the liquid crystal, wherein the liquid crystal is contained in a polymer matrix. When a polymer dispersed liquid crystal in which liquid crystal droplets are dispersed and held, and the surface tension of the polymer matrix is γpoly and the surface tension of the liquid crystal material is γLC, γpol
It is characterized in that y and γLC satisfy the following relationship (3): γLC> γpoly (3)

According to the above configuration, by satisfying the relationship of the expression (3), the liquid crystal molecules are hardly wet at the liquid crystal / polymer interface, and the interface regulating force is reduced. as a result,
The liquid crystal molecules in the liquid crystal droplets of the polymer-dispersed liquid crystal are easily affected by the thermal mobility of the polymer matrix, and a polymer-dispersed liquid crystal having a large temperature dependence of scattering-transmission characteristics can be obtained. Therefore, in a dimming device using such a polymer dispersed liquid crystal, it is possible to automatically perform a dimming operation in response to a temperature change.

According to a third aspect of the present invention, in addition to the structure of the first or second aspect, at least one of the pair of glass substrates has an outer surface.
The color filter is provided.

With this configuration, if the colors of the color filters are appropriately selected, light control with a desired color can be performed.

According to a fourth aspect of the present invention, there is provided an automatic temperature control system, wherein the liquid crystal light adjusting device according to the first or second aspect is used as a light control glass window, and a constant reference voltage is applied to the light control glass window. It is characterized in that a current applying device for applying the voltage is provided, and the room temperature is controlled by dimming sunlight passing through the light control glass window in response to a change in the room temperature.

With this configuration, the sunlight passing through the light control glass window is automatically controlled in response to a change in the temperature in the room. Therefore, without the need for special sensors
The room temperature can be automatically controlled to be constant.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a temperature-sensitive liquid crystal light control device according to the present invention, a liquid crystal is sandwiched between a pair of glass substrates provided with electrodes. And a state in which the transparent state changes from one state to the other state. The liquid crystal light control device according to the present invention performs a light control operation by utilizing the characteristics of the liquid crystal. Therefore, the liquid crystal light control device according to the present invention has the same basic structure as a known light control device using a general liquid crystal device, but the liquid crystal used for the light control device has the above characteristics. In the present invention, there is a decisive difference, and the present invention has the greatest feature in using a liquid crystal having such characteristics.

The liquid crystal used in the present invention will be specifically described below. This liquid crystal is a polymer-dispersed liquid crystal in which liquid crystal droplets are dispersed and held in a polymer matrix. The solubility parameters of the oligomer material and the monomer material forming the polymer matrix are (SP) olig, (S
When P) mono is described and the solubility parameter of the liquid crystal material is described as (SP) LC, (SP) olig and (SP) LC satisfy the relationship of the formula (1), and
(SP) mono and (SP) LC are made of each oligomer material, monomer material and liquid crystal material satisfying the relationship of the formula (2).

The liquid crystal according to another embodiment is a polymer dispersed liquid crystal in which liquid crystal droplets are dispersed and held in a polymer matrix, and the surface tension of the polymer matrix is γpol
y and the surface tension of the liquid crystal material is γLC, γp
Poly and γLC may be manufactured from a material satisfying the relationship of the formula (3).

In the polymer-dispersed liquid crystals of the above embodiment and other embodiments, the scattering-transmission characteristics change with temperature. In other words, the polymer-dispersed liquid crystal has a characteristic that a voltage value (threshold) that changes from a cloudy state to a transparent state (or from a transparent state to a cloudy state) changes in response to a temperature change. It is.

This is considered to be due to the following operation. In a polymer-dispersed liquid crystal composed of a material satisfying the relationship of the formulas (1) and (2), the compatibility between the liquid crystal material and the polymer material is poor, and the interaction at the liquid crystal / polymer interface is small. It is thought that it has become. Therefore, it is considered that the liquid crystal molecules in the liquid crystal droplet are easily affected by the thermal mobility of the polymer matrix, and as a result, the temperature dependence of the scattering-transmission characteristics is increased. (Conversely, when the compatibility between the liquid crystal material and the polymer material is good and the interface interaction is large, the effect of the thermal mobility of the polymer matrix on the liquid crystal molecules is reduced, and the temperature dependence of the scattering-transmission characteristics is small. It is considered to be.)

In a polymer-dispersed liquid crystal composed of a material satisfying the relationship of the formula (3), the liquid crystal molecules are hardly wet at the liquid crystal / polymer interface, and the interface regulating force is reduced. As a result, it is considered that the liquid crystal molecules in the liquid crystal droplet are easily affected by the thermal mobility of the polymer matrix, and the temperature dependence of the scattering-transmission characteristics is increased. (Conversely, if the wetting property at the liquid crystal / polymer interface is good, the interface interaction increases, the effect of the thermal mobility of the polymer matrix on the liquid crystal molecules is reduced, and the temperature dependence of the scattering-transmission characteristics is reduced. It is thought to be smaller.)

The material for forming the polymer matrix is as follows:
The oligomer and the monomer include a polymerization initiator that initiates polymerization by light or heat. The monomer material is not particularly limited as long as it is polymerized and cured by light or heat and satisfies the formula (2) or the formula (3), but is not particularly limited to 2-ethylhexyl acrylate,
2-hydroxyethyl acrylate, neopentyl glycol acrylate, hexanediol diacrylate, diethylene glycol diacrylate, tripropylene glycol diacrylate, polyethylene glycol diacrylate, generally commercially available acrylic monomers such as trimethylolpropane triacrylate,
Further, a wide variety of non-acrylic commercial products can be applied.

The oligomer is not particularly limited as long as it satisfies the formula (1) or the formula (3), and urethane acrylates, ester acrylates, epoxy acrylates and the like can be used. Further, the polymerization initiator is also Darocure 1173 (manufactured by Ciba Gaiki Co., Ltd.), Darocure 4265, Irgacure 184, and Irgacure 65.
1, etc. can be widely used.

In this way, the present inventor controls the temperature dependence of the scattering-transmission characteristics of the polymer-dispersed liquid crystal, and responds to temperature by changing from one of the cloudy state and the transparent state to the other. Thus, a polymer-dispersed liquid crystal having the property of changing to a state was obtained. Then, by applying this liquid crystal to a light control device, a novel temperature-sensitive liquid crystal light control device capable of automatically performing a light control operation in response to a temperature change was realized. In addition, as the light control element, a color filter may be provided on an outer surface of at least one of the pair of glass substrates. In this way, by appropriately selecting the color of the color filter, light control with a desired color can be performed.

Further, the present inventor has completed an automatic temperature control system for automatically keeping the room temperature constant by using such a temperature-sensitive liquid crystal light control device for a light control glass window. FIG.
1 is a schematic diagram of an automatic temperature control system according to the present invention for automatically keeping a room temperature constant. A light control glass window 11 is arranged in the window of the room 10. This dimmable glass window 1
1 is connected to a power supply device 12, and a constant voltage is applied to the light control glass window 11. The light control glass window 11 used is such that the voltage at which the state switches from the scattering state (white turbid state) to the transmission state (transparent state) increases as the temperature increases. Further, in relation to the light control glass window 11, the light control glass window 11 is, for example, transparent on the outdoor side of the light control glass window 11 so as to be affected only by the room temperature and not by the outdoor temperature. A heat insulator (not shown) and the like are provided.

In the automatic temperature control system having such a configuration, first, it is assumed that the room temperature is high and the threshold value of the polymer dispersed liquid crystal is higher than the voltage value applied to the light control glass window 11. . In such an initial state, the light control glass window 11 is in a transmission state, and the sunlight 13 irradiates the room 10 through the light control glass window 11. In such a state, when the room temperature starts to rise due to the sunlight 13, the threshold value increases accordingly. For this reason, the transmittance of the polymer-dispersed liquid crystal automatically decreases,
The sunlight 13 passing through the light control glass window 11 is shut off, and an increase in room temperature is suppressed. Conversely, when the room temperature decreases, the threshold value correspondingly decreases. For this reason, the transmittance of the polymer-dispersed liquid crystal increases, the sunlight 13 enters, and the room temperature automatically increases. Thus, only by applying a constant voltage to the light control glass window, the light control glass window can automatically perform the light control operation in response to a change in the room temperature. Can be controlled to be constant.

As the polymer-dispersed liquid crystal used for the light control glass window, in addition to the above-mentioned type, in which the voltage at which the state switches from the scattering state (white turbid state) to the transmission state (transparent state) increases as the temperature increases, the scattering state becomes higher. A type in which the voltage at which the voltage changes from (white turbid state) to transmissive state (transparent state) becomes lower as the temperature becomes higher can also be used. Further, the liquid crystal light control glass window is not limited to the above-mentioned room window, and can be used in a wide range of fields such as application to windows such as microwave ovens and hot plates. Furthermore, the dimming element according to the present invention can be widely used in addition to the dimming glass window, for example, a component of an optical device, a dimming system other than the temperature control system, and the like. It is.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. Embodiment 1 FIG. 2 is a schematic sectional view of a liquid crystal light control device according to the present invention. In the figure, reference numerals 31 and 32 denote a pair of glass substrates, and on the inner surfaces of the substrates 31 and 32, a transparent electrode 33 made of indium / tin oxide and an insulating film 34 are formed, respectively. A pair of substrates 31 and 32 are arranged such that their transparent electrodes 33 face each other at a predetermined interval, and a polymer matrix in which liquid crystal droplets 36 are dispersed and held in a polymer matrix 35 between the opposed transparent electrodes 33. Dispersion type liquid crystal 37 is arranged. Further, the transparent electrodes 33 facing each other are bonded together by a spacer / seal resin 38, and the polymer dispersed liquid crystal 37 is sealed to form a liquid crystal light adjusting element 39.

In FIG. 2, the liquid crystal droplets 36 are scattered independently in the form of islands in the polymer matrix 35, but the existence of the liquid crystal droplets 36 is not limited to this. For example, a part of the liquid crystal droplets may exist in a state of being in contact with each other and continuing.

FIG. 3 is a perspective view showing the state of the manufacturing process of the liquid crystal light adjusting device. With reference to FIG. 3, a method of manufacturing the liquid crystal light adjusting device will be described below. Two glass plates (glass substrates 31 and 32) on which a transparent electrode 33 made of indium tin oxide and an insulating film 34 are formed are prepared, and a spacer is provided on one of the glass substrates (for example, a lower glass substrate 32). As the sealing resin 38, an acid anhydride-curable epoxy resin in which glass fibers having a diameter of 13 μm were dispersed was printed on the four edges at a width of 5 mm. In addition, one side was left 1 mm wide as the opening 40. Next, the upper glass substrate 31 and the lower glass substrate 32
Were pressed in this state, and heated and bonded at 140 ° C. for 4 hours to complete an empty cell.

Next, as a liquid crystal material, TL213 composed of a material having a solubility parameter of about 9.5.
(Manufactured by Merck Ltd.) as perfluorooctylethyl acrylate F as a polymer-forming monomer.
A108 (manufactured by Kyoeisha Chemical Co., Ltd .; solubility parameter: about 5.7) was 20.0 g, and KAYA was used as an oligomer.
4.5 g of RAD PEG400DA (manufactured by Nippon Kayaku Co., Ltd .; solubility parameter: about 7) and 0.5 of Darocure 1173 (manufactured by Cibagaiki Co., Ltd.) as a photopolymerization initiator.
g was prepared, and the respective materials were added to form a polymerizable composition 41. Therefore, in the first embodiment,
(SP) olig <(SP) LC-2 and (SP)
mono <(SP) LC-2, which satisfies the expressions (1) and (2).

Next, the polymerizable composition 41 is sufficiently stirred at 25 ° C., and the opening 40 is inserted into the empty cell at 25 ° C.
From the injection, after the injection is completed, after sealing the opening 40,
365 nm ultraviolet light (24.5 mW / cm @ 2) at 25 DEG C.
For 100 seconds, and the polymer-dispersed liquid crystal is
A liquid crystal light control device sandwiched between the first and second liquid crystal devices was completed.

Next, the temperature dependence of the driving voltage of the liquid crystal light control device completed as described above is determined by measuring the temperature dependence of 10 ° C., 20 ° C., and 30 ° C.
Evaluation was performed using a liquid crystal evaluation device (LCD-5000, manufactured by Otsuka Electronics Co., Ltd.) under two temperature conditions. The measurement was performed at a measurement frequency of 30 Hz and a light receiving angle of 2.8 °. The measurement results are shown in FIG. As is clear from FIG. 4, the voltage at which the state changes from the scattering state (opaque state) to the transmission state (transparent state) becomes higher as the temperature becomes higher.
Focusing on the transmittance at the time of applying a volt, about 90 at 10 ° C.
%, About 50% at 20 ° C, and about 5% at 30 ° C. This means that a temperature-sensitive liquid crystal light control device that performs a light control operation in response to a temperature change has been realized.

Example 2 In Example 2, 82.00 grams of a liquid crystal material (MT5524, manufactured by Nissan Corporation) having a surface tension of 29.4 dyne / cm at 20 ° C. was used as a polymer-forming monomer. 9.54 g of lauryl acrylate (manufactured by Nakarai Tesque Co., Ltd.), 8.08 g of M6100 (manufactured by Toa Gosei Chemical Co., Ltd.) as an oligomer, and Darocure 1173 (manufactured by Cibagaiki Co., Ltd.) as a photopolymerization initiator. Using 0.38 g, a liquid crystal light control device was produced in the same manner as described in Example 1. The surface tension of the polymer matrix thus completed was measured using a wettability test agent after washing and drying only the liquid crystal from the polymer-dispersed liquid crystal with isopropyl alcohol.
It was 26.5 dyne / cm at 0 ° C. Therefore, in Example 2, γLC> γpoly is clearly satisfied.
Equation (3) is satisfied.

Next, the temperature dependence of the drive voltage of the liquid crystal light control device completed in this manner was determined by measuring the temperature dependence of 10 ° C., 20 ° C., and 30 ° C.
Evaluation was performed using a liquid crystal evaluation device (LCD-5000, manufactured by Otsuka Electronics Co., Ltd.) under two temperature conditions. The measurement was performed at a measurement frequency of 30 Hz and a light receiving angle of 2.8 °. The measurement results are shown in FIG. As is apparent from FIG. 5, the voltage at which the state changes from the scattering state (opaque state) to the transmission state (transparent state) increases as the temperature increases. For example, 5
Focusing on the transmittance at the time of applying a volt, about 90 at 10 ° C.
%, About 60% at 20 ° C, and about 5% at 30 ° C. This means that a temperature-sensitive liquid crystal light control device that performs a light control operation in response to a temperature change can be realized in the second embodiment as well as in the first embodiment.

Example 3 In Example 3, 75.0 TL213 (manufactured by Merck Ltd.) composed of a material having a solubility parameter of about 9.5 was used as a liquid crystal material.
Gram, as a polymer-forming monomer, perfluorooctylethyl acrylate FA108 (Kyoeisha Chemical Co., Ltd.)
20.0 grams, with a solubility parameter of about 5.7)
M6100 (produced by Toa Gosei Chemical Co., Ltd.) as an oligomer;
A solubility parameter of about 12) was set to 8.08 g, and Darocur 1173 (Cibagaiki Co., Ltd.) was used as a photopolymerization initiator.
) Was used in the same manner as described in Example 1 to produce a liquid crystal light control device. Therefore, in the third embodiment, (SP) olig> (S
P) LC + 2 and (SP) mono <(SP) LC
−2, which satisfies the expressions (1) and (2).

Next, the temperature dependence of the driving voltage of the liquid crystal light control device completed as described above was determined by measuring the temperature dependence of 10 ° C., 20 ° C., and 30 ° C.
Evaluation was performed using a liquid crystal evaluation device (LCD-5000, manufactured by Otsuka Electronics Co., Ltd.) under two temperature conditions. The measurement was performed at a measurement frequency of 30 Hz and a light receiving angle of 2.8 °.

FIG. 6 shows the measurement results. This figure 6
As is clear from FIG. 5, the voltage at which the state changes from the scattering state (white turbid state) to the transmission state (transparent state) increases as the temperature increases. For example, focusing on the transmittance when 5 volts are applied, about 90% at 10 ° C., about 50% at 20 ° C., and 30 ° C.
Was about 5%. This means that a temperature-sensitive liquid crystal light control device that performs a light control operation in response to a temperature change can be realized in the third embodiment as in the first and second embodiments.

(Comparative Example 1) TL2 composed of a material having a solubility parameter of about 9.5 as a liquid crystal material
7 (manufactured by Merck) and 2-ethylhexyl acrylate (manufactured by Nacalai Tesque, Inc .; solubility parameter: about 9.5) as a polymer-forming monomer.
20.0 grams, KAYARAD as oligomer
4.5 g of HDDA (manufactured by Nippon Kayaku Co., Ltd .; solubility parameter: about 9), Darocur 1 as a photopolymerization initiator
0.5 g of 173 (manufactured by Ciba Gaiki Co., Ltd.) was prepared, and a liquid crystal light adjusting device was manufactured in the same manner as described in Example 1. Therefore, Comparative Example 1 does not satisfy either of the expressions (1) and (2).

Next, the temperature dependence of the drive voltage of the liquid crystal light control device completed as described above was determined by measuring the temperature dependence of 10 ° C., 20 ° C., and 30 ° C.
Evaluation was performed using a liquid crystal evaluation device (LCD-5000, manufactured by Otsuka Electronics Co., Ltd.) under two temperature conditions. The measurement was performed at a measurement frequency of 30 Hz and a light receiving angle of 2.8 °. The result is shown in FIG. As is clear from FIG. 7, the scattering-transmission characteristics have almost no temperature dependence.

Comparative Example 2 Of the materials constituting Example 2, the monomer material was 2-ethylhexyl acrylate and the oligomer material was M1600 (Toa Gosei Chemical Co., Ltd.)
The other configurations were the same as in Example 2, and a liquid crystal light modulating device was manufactured in the same manner as in Example 2. When the surface tension of the polymer matrix of this liquid crystal light control device was evaluated by the same method as described in Example 2, the critical surface tension was 30.5 dyne / cm at 20 ° C. Therefore, Expression (3) is not satisfied.

Further, the temperature dependence of the driving voltage of the liquid crystal light control device was determined under three temperature conditions of 10 ° C., 20 ° C., and 30 ° C.
Liquid crystal evaluation device (LCD-5000, manufactured by Otsuka Electronics Co., Ltd.)
Was evaluated using The measurement was performed at a measurement frequency of 30 Hz and a light receiving angle of 2.8 °. The result is shown in FIG. As is clear from FIG. 8, there was almost no temperature dependency.

Comprehensively judging based on the measurement results of Examples 1 to 3 and Comparative Examples 1 and 2, the oligomer material, the monomer material and the liquid crystal material were determined by the formulas (1) and (2). It is concluded that satisfying the relationship or satisfying the relationship of Expression (3) is an essential requirement for establishing the temperature dependence of the liquid crystal light control device.

In the above Examples 1 to 3 and Comparative Examples 1 and 2, the solubility parameter used was a value calculated from the cohesive energy, molecular weight and density of the material, but the molecular volume at each temperature (or the reciprocal thereof) was used. Density) and a value obtained from heat of evaporation, or a value obtained from surface tension and molecular volume. The weight ratio of the polymer-dispersed liquid crystal according to the present invention is not limited to those described in Examples 1 to 3.

In the first to third embodiments, the oligomer material, the monomer material, and the liquid crystal material are used as one type. However, the present invention is not limited to this, and the first (1)
The relationship between the expression and the expression (2) is satisfied or the expression (3)
As long as the material satisfies the relationship of the formula, several kinds of materials may be mixed and used.

Next, the automatic temperature control system according to the present invention will be described in more detail with reference to examples. Specifically, in the automatic temperature control system of FIG. 1, each of the liquid crystal light control devices of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 is a light control glass window, Attached. A voltage of 5 volts was constantly applied to each light control glass window, and the temperature change inside the room during the day from sunrise to sunset was examined.

The results are shown in FIGS. FIG. 9 shows a temperature change when each of the liquid crystal light control devices of the first and second embodiments is used as a light control glass window. In FIG. 9, circles indicate liquid crystal light control of the first embodiment. The device is used for a light control glass window, and the triangle mark indicates the case where the liquid crystal light control device of Example 2 is used for a light control glass window. Also,
FIG. 10 shows a temperature change when each of the liquid crystal light control devices of Comparative Example 1 and Comparative Example 2 was used as a light control glass window. In FIG. The device is used for a light control glass window, and the triangle mark indicates the case where the liquid crystal light control device of Comparative Example 2 is used for a light control glass window. From FIGS. 9 and 10, it is apparent that Comparative Example 1 and Comparative Example 2 were used.
In comparison with the case where the liquid crystal light control device of Example 1 was used, the temperature change inside the room was remarkably smaller when the liquid crystal light control device of Example 1 or 2 was used, and a comfortable environment was obtained.

[0050]

As described above, according to the present invention, the polymer-dispersed liquid crystal of the light modulating element can be used to make the polymer material forming the polymer matrix and the solubility parameter of the liquid crystal material satisfy the relationship of the formula (1). In addition, by using the oligomer material, the monomer material, and the liquid crystal material having the solubility parameters of the monomer material and the liquid crystal material satisfying the relationship of the expression (2), the light control is automatically performed according to the temperature change. Performing the operation can realize a novel temperature-sensitive liquid crystal light control device.

Further, a polymer-dispersed liquid crystal of the light control device is manufactured using each oligomer material, monomer material and liquid crystal material whose surface tension of the polymer matrix and the liquid crystal material satisfies the relationship of the formula (3). By doing so, it is also possible to realize a temperature-sensitive liquid crystal light control device in which the light control operation is automatically performed in response to the same temperature change as described above.

Further, by using the temperature-sensitive liquid crystal light control device as a light control glass window, a system capable of automatically controlling the temperature can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic view of an automatic temperature control system according to the present invention for automatically keeping a room temperature constant.

FIG. 2 is a schematic sectional view of a liquid crystal light control device according to the present invention. FIG. 3 is a schematic diagram illustrating a display principle of a device manufactured using a polymer-dispersed liquid crystal.

FIG. 3 is a perspective view showing a state of a manufacturing process of the liquid crystal light adjusting device according to the present invention.

FIG. 4 is a diagram showing the temperature dependence of the scattering-transmission characteristics of the liquid crystal light adjusting device of Example 1.

FIG. 5 is a diagram showing the temperature dependence of the scattering-transmission characteristics of the liquid crystal light control device of Example 2.

FIG. 6 is a diagram showing the temperature dependence of the scattering-transmission characteristics of the liquid crystal light adjusting device of Example 3.

FIG. 7 is a diagram showing the temperature dependence of the scattering-transmission characteristics of the liquid crystal light control device of Comparative Example 1.

FIG. 8 is a diagram showing the temperature dependence of the scattering-transmission characteristics of the liquid crystal light adjusting device of Comparative Example 2.

FIG. 9 is a diagram showing a temperature change in a room in an automatic temperature control system using each of the liquid crystal light control devices of Example 1 and Example 2 as a light control glass window.

FIG. 10 is a diagram showing a temperature change in a room in an automatic temperature control system using each of the liquid crystal light control devices of Comparative Examples 1 and 2 as a light control glass window.

FIG. 11 is a diagram for explaining a display principle of a polymer dispersed liquid crystal which is a basis when the polymer dispersed liquid crystal is applied to a light control device.

[Explanation of symbols]

 11: dimming glass window 12: conducting device 13: sunlight 31, 32: glass substrate 33: transparent electrode 35: polymer matrix 36: liquid crystal drop 37: polymer dispersed liquid crystal 39: liquid crystal dimming element 41: polymerization Composition

Claims (4)

[Claims] A liquid crystal is sandwiched between a pair of glass substrates provided with electrodes, and the liquid crystal changes from one of a cloudy state and a transparent state to the other state in response to temperature. A temperature-sensitive liquid crystal light control device that performs a light control operation by the characteristics of the liquid crystal, wherein the liquid crystal is a polymer dispersion type in which liquid crystal droplets are dispersed and held in a polymer matrix. The solubility parameters of the oligomer material and the monomer material which are liquid crystal and form the polymer matrix are described as (SP) olig and (SP) mono, respectively, and the solubility parameter of the liquid crystal material is (SP) LC
When (SP) olig and (SP) LC are expressed by the following expression (1), the following equation (1) is used: (SP) olig> (SP) LC + 2 or (SP) olig <(SP) LC-2 (1) And (SP) mono and (SP) LC satisfy the following expression (2): (SP) mono> (SP) LC + 2 or (SP) mono <(SP) LC-2 (2) A temperature-sensitive liquid crystal light control device, characterized by satisfying the following. 2. A liquid crystal is sandwiched between a pair of glass substrates provided with electrodes, and the liquid crystal changes from one of a cloudy state and a transparent state to the other state in response to temperature. A temperature-sensitive liquid crystal light control device that performs a light control operation by the characteristics of the liquid crystal, wherein the liquid crystal is a polymer dispersion type in which liquid crystal droplets are dispersed and held in a polymer matrix. When the surface tension of the polymer matrix is γpoly and the surface tension of the liquid crystal material is γLC, γpoly and γLC satisfy the following expression (3): γLC> γpoly (3) Characteristic temperature-sensitive liquid crystal light control device. 3. The temperature-sensitive liquid crystal light control device according to claim 1, wherein a color filter is provided on an outer surface of at least one of the pair of glass substrates. . 4. The liquid crystal light control device according to claim 1 or 2 is used as a light control glass window, and an energizing device for applying a constant reference voltage to the light control glass window is provided to change the temperature of the room. An automatic temperature control system, wherein the indoor temperature is controlled by dimming sunlight passing through a dimming glass window corresponding to the temperature.