JPH07318982A - Light scattering type light controlling element using liquid crystal composition - Google Patents

Abstract

PURPOSE:To obtain a light scattering type light-controlling element having both of memory property and rapid responsiveness by preparing a liquid crystal compsn. containing flat particles having affinity with the liquid crystal. CONSTITUTION:The liquid crystal compsn. contains flat particles 1 showing affinity with the liquid crystal. When the liquid crystal compsn. is kept at a temp. where the liquid crystal state is maintained (the liquid crystal temp.) without applying voltage, the particles 1 are dispersed in random directions to form lots of loose cell structures 2. The orientation of liquid crystal molecules 3 is random for each individual domain so that the liquid crystal compsn. shows a light scattering state. When voltage is applied, the liquid crystal molecules 3 are oriented along the direction of voltage applied so that the particles 1 are orientated in the same direction to give a light transmitting state of the compsn. Even after the voltage is removed, orientation of particles 1 is maintained so that the light transmitting state is maintained. When the liquid crystal compsn. in the memory state is heated to the isotropic temp. and then cooled to the liquid crystal temp. again, the liquid crystal compsn. shows the light scattering state again. As for flat particles 1, organic laminar clay mineral is preferable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light scattering type light control device using a liquid crystal composition.

[0002]

2. Description of the Related Art Conventionally, elements called so-called twisted nematic liquid crystal elements and ferroelectric liquid crystal elements have been provided. However, it has been pointed out that these elements require the use of a polarizing plate, and that the utilization efficiency of light is not high, so that it is difficult to display bright images and that the viewing angle is not wide.

Therefore, in order to solve the above-mentioned drawbacks, the orientation direction of the domains of the liquid crystal is randomized to create a light-scattering state to realize the light-shielding state, while applying an electric field to align the orientation directions of the domains. Therefore, the development of a so-called field-effect light-scattering type light control material that realizes a light-transmitting state has been attempted, and its application as a light control / display element has been studied.

As such a light scattering type light control material, for example, it is disclosed as "liquid crystal light modulation material" in Japanese Patent Publication No. 63-501512, or Japanese Patent Publication No. 3-528.
There is a polymer-dispersed liquid crystal disclosed in Japanese Patent Laid-Open No. 43 as "liquid crystal constituent and liquid crystal optical device". These polymer-dispersed liquid crystals are domains in which a large number of small vesicles provided in a dispersed state in a transparent polymer material matrix are filled with a low-molecular liquid crystal (first conventional technique). ).

On the other hand, a low molecular weight liquid crystal-polymer liquid crystal composite has been proposed as a light scattering type light control material having a memory property. As an example of this, T. Kajiyama et al., Chemistry Le
Examples include those disclosed in tters, p817-820, 1989.
In the case of this composite, there is a memory property that it becomes transparent when the high-frequency AC electric field is turned on, returns to opaque when the low-frequency AC electric field is turned on, and remains stable in each state even after the electric field is removed (second Prior art).

[0006]

However, the polymer-dispersed liquid crystal according to the first prior art is a system in which the light-transmitting state of the low-molecular liquid crystal is maintained by applying an electric field. In order to maintain it, the electric field must always be applied. That is, there is no so-called memory property. Therefore, this type of light scattering type light control material is not advantageous in terms of durability of the liquid crystal and power consumption.

Further, the composite according to the second prior art has a drawback that the viscosity of the system is increased due to the use of the polymer liquid crystal, and the response time is extremely longer than that of a normal liquid crystal system. That is, combining the first conventional technology and the second conventional technology, in the conventional field effect type light scattering type light control material,
Nothing has been developed yet that has both memory characteristics and high-speed responsiveness that are difficult to combine.

(Object of the Invention) Therefore, an object of the present invention is to provide a light-scattering type light control device of the field effect type, which has both a memory property and a high-speed response property. Further, the present invention, for such a light-scattering type light control element, further increases the difference in the amount of light transmission between the light transmission state and the light scattering state, that is, increases the light control contrast of the light control element. It is also intended to do.

(Points of Interest) As a result of research to achieve the above object, the inventor of the present invention has found that flat particles exhibiting an affinity with the liquid crystal are present in a liquid crystal having electric field response and positive dielectric anisotropy. If a composition that is added and dispersed is prepared, it can be used as a light control element through various controls such as orientation control of liquid crystal molecules (or liquid crystal molecules and flat particles) by an electric field and control of liquid crystal phase change by a temperature field. We have come to the conclusion that we can realize useful functional changes.

Further, the light-scattering type light-controlling material which exclusively utilizes the light-scattering effect can be made to have a light-absorbing effect at the same time. It was

The inventor of the present invention has completed the present invention based on the above points.

[0012]

[Means for Solving the Problems]

(Structure of the first invention of the present application) The structure of the first invention of the present application (the invention according to claim 1) for solving the above-mentioned problems is a hollow cell in which at least a light transmitting portion is made of a transparent material, A liquid crystal whose main component is a liquid crystal molecule having an electric field responsiveness and a positive dielectric anisotropy, which is filled in the cell, and a liquid crystal dispersed in the liquid crystal at a density such that domains of the liquid crystal are effectively formed. A liquid crystal composition comprising flat particles exhibiting an affinity for, an electric field applying means provided in the cell, capable of applying an electric field to the liquid crystal composition, and attached to the cell, A light scattering type light control device, comprising: a memory state releasing means having a function of forming domains of a liquid crystal composition.

(Structure of the Second Invention of the Present Application) The structure of the second invention of the present application (the invention according to claim 2) for solving the above problems is a hollow structure in which at least a light transmitting portion is made of a transparent material. A cell, a liquid crystal filled in the cell, the liquid crystal having an electric field responsive and positive dielectric anisotropy as a main component, a dichroic dye contained in the liquid crystal, and the liquid crystal An electric field is applied to the liquid crystal composition, which is provided in the cell, and a liquid crystal composition containing flat particles having an affinity for the liquid crystal, dispersed in a density such that domains of the liquid crystal are effectively formed. It is a light-scattering type light control device comprising: an electric field applying means capable of performing the above operation; and a memory state releasing means attached to the cell and having a function of forming domains of the liquid crystal composition.

(Structure of the third invention of the present application) The structure of the third invention of the present application (the invention according to claim 3) for solving the above-mentioned problems is the memory state releasing means in the first invention or the second invention. Is a light-scattering type light control device comprising one or more means for controlling the temperature of the liquid crystal composition or means for applying a shearing force to the liquid crystal composition.

(Structure of Fourth Invention of the Present Application) The structure of a fourth invention of the present application (an invention according to claim 4) for solving the above-mentioned problems is any one of the first to third inventions, wherein the liquid crystal is , A light-scattering-type light control element that is a liquid crystal that causes a phase change between a liquid crystal state and an isotropic state in a temperature range in which a normal light control element is commonly used.

(Structure of the Fifth Invention of the Present Application) The structure of the fifth invention of the present application (the invention according to claim 5) for solving the above-mentioned problems is the liquid crystal molecule according to any one of the first invention to the fourth invention. Is a light-scattering type light control device in which is a low molecular weight molecule.

(Structure of the sixth invention of the present application) The structure of the sixth invention of the present application (the invention according to claim 6) for solving the above-mentioned problems is the flat shape according to any one of the first invention to the fifth invention. Is a light-scattering type light control element in which the particles of (1) are particles exhibiting electric field response.

(Structure of the seventh invention of the present application) In the structure of the seventh invention of the present application (the invention according to claim 7) for solving the above-mentioned problems, in the first invention to the sixth invention, the flat particles are It is a light scattering type light control device which is an organically modified layered clay mineral.

[0019]

[Action]

(Operation of the first invention) The operation of the first invention is shown in FIGS.
A description will be given based on (a) to FIG. FIG. 1 is a light-scattering type dimming device of the first invention in which a liquid crystal composition is enclosed in a dimming element device (not shown) made of a transparent material, which is provided with a transparent electrode and has a temperature control means or a shearing force applying means. The change of the light transmission amount of the light control element when a light beam is incident on the element while controlling the electric field, the temperature field and the like according to a predetermined program is shown. FIGS. 2A to 2E are estimates of the state of the liquid crystal composition corresponding to the change in the amount of light transmission shown in FIG. In addition, since the particles having the affinity for the liquid crystal are used as the flat particles, the flat particles are always well dispersed in the liquid crystal. Further, in the explanation of this action, it is premised that the flat particles are included in the density such that the light scattering action thereof does not substantially affect the light transmittance of the liquid crystal composition.

First, when the liquid crystal composition of the light control element is placed in a state in which no voltage is applied at a liquid crystal temperature (so-called temperature at which the liquid crystal state is maintained), flat particles 1 are formed as shown in FIG. 2 (a). The particles are randomly oriented and dispersed, and as a result, a large number of loose cell structures 2 whose periphery is divided by the individual flat particles 1 are formed. Since the orientation of the liquid crystal molecules 3 forming domains inside each cell structure 2 is restricted by the orientation of the flat particles 1 partitioning the cell structure 2, the orientation of the liquid crystal molecules 3 becomes random for each domain, The composition is in a state of small light transmission (light scattering state). Therefore, the light transmission amount of the light control element is small as indicated by (1) in FIG.

Next, when a voltage is applied to the light control element by the transparent electrode, the electric field responsive liquid crystal molecule 3 has a positive dielectric anisotropy as shown in FIG. Orient along. At this time, even if the flat particles 1 do not have electric field response by themselves, it is considered that the liquid crystal molecules 3 are driven by the force to be aligned and consequently are aligned in the same direction. As a result, the cell structure 2 described above is eliminated, and the liquid crystal composition is in a state where the amount of light transmission is large (light transmission state). Therefore, the light transmission amount of the light control element also becomes large as shown by (2) in FIG. The change from (1) to (2) in FIG. 1 is extremely rapid, generally 10 to
Since the response time is about 20 milliseconds, it can be said that there is a high-speed response.

Even if the voltage application is canceled here, as shown in FIG.
As shown in (3), the light transmission amount of the light control element shows only a slight decrease, and this light transmission state is maintained unless special interference from the external field is added. That is, the light control element has a memory property. It is estimated that this memory property is based on the following mechanism.

That is, even if the voltage application to the light control element is released, the orientation of the flat particles 1 is maintained, and all the liquid crystal molecules 3 in the liquid crystal composition are flat particles at the liquid crystal temperature. The light control element does not return to the light-scattering state as shown in FIG. 2A because it is oriented in the same direction as 1. The reason why the light transmission amount of the light control element slightly decreases in this memory state is not necessarily perfect because the orientation of the particles 1 in the voltage applied state is not due to its own force, and there is a slight variation in the orientation. It is presumed that this is because when the voltage application is released, an extremely incomplete domain with slight variations in alignment of the liquid crystal molecules is formed when the voltage application is released, as shown in FIG. It

As an effective and practical means for canceling the above-mentioned memory state, as shown in the third aspect of the invention, two kinds of means have so far been known.

The first memory state releasing means is to raise the temperature of the liquid crystal composition in the light control element to an isotropic temperature. That is, if the temperature control means raises the temperature of the liquid crystal composition in the memory state to an isotropic temperature and then lowers it to the liquid crystal temperature again, the light transmission amount of the liquid crystal composition once becomes slightly large and then becomes significantly small. , Return to the light scattering state. Therefore, the light transmission amount of the light control element once becomes slightly large as shown in (4) of FIG. 1 and then becomes significantly small as shown in (5) of FIG. From this, the light control element of the first invention has a memory property and a high-speed response, and can change between the light scattering state and the light transmitting state depending on the temperature field.

The mechanism for canceling the memory state in this case is estimated as follows. That is, when the temperature of the liquid crystal composition is raised to the isotropic temperature, the liquid crystal molecules 3 in the liquid crystal composition are changed to those shown in FIG.
As shown in FIG. 2, the isotropic state of randomly aligning is realized, and the light transmission amount of the light control element is slightly increased. At this time, the isotropic state of the liquid crystal molecules 3 affects the particle 1
The variation in the orientation of is also large. Then, when the temperature is lowered to the liquid crystal temperature again, a large number of loose cell structures 2 are formed by the particles 1 that are aligned with variations, and the alignment of the liquid crystal molecules 3 that form the domains therein becomes random for each domain, and the liquid crystal composition becomes It returns to the scattered state.

At this time, the light scattering state shown by (5) in FIG. 1 may have a larger light transmission amount than the light scattering state shown by (1) in FIG. When it is desired to cancel such a state completely, the liquid crystal composition in the light control element is completely given the light scattering state shown in FIG. 2 (e) by applying a shearing force which is the second means described below. (Equivalent to the light scattering state shown in FIG. 2A.) And the light transmission amount of the light control element also returns to the level shown in (1) in FIG. In addition, the light transmission state of FIG. 2B can be equally reproduced by applying the voltage as it is after releasing the memory state or applying the voltage after applying the shearing force.

By the way, when the electrolyte such as tetrabutylammonium bromide or tetraethylammonium bromide is contained at a predetermined concentration of, for example, about 0.5 to 0.001 part by weight with respect to 100 parts by weight of the liquid crystal. The temperature of the liquid crystal composition rises just by passing an electric current through the liquid crystal composition. Then, when the energization is stopped, the temperature of the liquid crystal composition is lowered. Therefore, when the liquid crystal composition contains an electrolyte as described above, there is a possibility that it can be used as a temperature control means by energizing.

The second memory state releasing means is a means suitable for the dimming element in the memory state, which is used to shift from the outside.
It is to give a shearing force such as vibration and impact. When a shearing force is applied to the light control element, the particles 1 in the liquid crystal composition are in a random alignment state at once, returning to the light scattering state shown in FIG. 2 (e), and the light transmission amount of the light control element is also shown in FIG. Return to the level shown in (1). That is, in this case, the light transmission amount returns from the level (3) in FIG. 1 to the level (1) in FIG. 1 according to the pattern indicated by the alternate long and short dash line.

In the above description of the operation of the first invention, it is premised that the flat particles are included in the density at which the light scattering effect does not substantially affect the light transmittance of the liquid crystal composition. There is. However, even if the particles 1 are contained at a density that substantially affects the light transmittance of the liquid crystal composition, the light scattering state of the liquid crystal composition shown in FIGS. 2A and 2E is shown. In the above, since the light scattering action by the particles 1 dispersed in a random orientation is added, the light transmission amount of the light control element is further reduced. Therefore, the difference in the amount of light transmission between the light scattering state and the light transmitting state of the light control element is further increased. That is, the dimming contrast becomes higher. Other points are basically the same as the above-mentioned operation.

(Operation of Second Invention) In the second invention, a dichroic dye contained in the liquid crystal is further added as a component to the liquid crystal composition used in the light control element of the first invention. It is a composition. Therefore, by selecting and using various kinds of dyes having different absorption spectra, it is possible to perform multi-coloring in which an arbitrary color is imparted to the transmitted light of the light control element.

On the other hand, in the light-scattering state of the liquid crystal composition shown in FIG. 2A, the dichroic dyes are also randomly oriented to exhibit a light-absorbing effect, and the light-transmitting state shown in FIG.
In the memory state of (c), the liquid crystal molecules are driven to be aligned and the dichroic dye is also aligned, so that the light absorption effect is almost eliminated. When a shearing force is applied to the light control element, the dichroic dye returns to a random orientation, and the light absorption effect appears again. That is, the light absorption effect of the dichroic dye appears and disappears in synchronization with the light-scattering state and the light-transmitting state of the liquid crystal composition, so that the dimming contrast of the light control element is further increased. Other points are first
The operation of the invention is basically the same.

(Operation of Third Invention) In the third invention,
The memory state releasing means is composed of one or more of a temperature control means and a shearing force applying means. The contents of the action of each means are as described in the explanation of the action of the first invention.

(Operation of Fourth Invention) In the fourth invention, as the liquid crystal of the liquid crystal composition used for the light control element, the liquid crystal composition is between a liquid crystal state and an isotropic state in the temperature range where a normal light control element is usually used. Use the one that causes a phase change. Therefore, the temperature control as the memory state releasing means is performed in such a normal temperature range. This contributes to expansion of applications of the light control device and improvement of durability. Other points are first
The operation of the invention to the third invention is basically the same.

(Operation of Fifth Invention) In the fifth invention, the liquid crystal molecules of the liquid crystal composition used for the light control element are low molecular weight molecules. Therefore, when the liquid crystal composition of the light control element is in the light scattering state of FIG. 2 (a), when a voltage is applied to it, the liquid crystal molecules are more rapidly aligned. Therefore, the high speed response of the light control element is further improved. Other points are basically the same as those of the first to fourth inventions.

(Operation of Sixth Invention) In the sixth invention, the flat particles contained in the liquid crystal composition are particles exhibiting electric field response. Therefore, when a voltage is applied to the liquid crystal composition in the light-scattering state shown in FIG. 2A, not only the liquid crystal molecules but also the flat particles are oriented autonomously. There is no slight variation in the orientation of the flat particles, and the light transmission amount of the light control element is further increased. As a result, the dimming contrast of the dimming element becomes higher than that of the first invention. Other points are the first invention ~
It is basically the same as the operation of the fifth invention.

(Operation of Seventh Invention) In the seventh invention, the flat particles are organically modified layered clay minerals. Organized layered clay minerals have affinity for liquid crystals and electric field response. Further, the layered clay mineral becomes a particle having a large aspect ratio, which is separated into crystal layer units by being organized. From the above, the organically modified layered clay mineral is one of the most suitable constituent materials for the cell structure for partitioning the domains of the liquid crystal. Therefore, in the seventh invention, various actions of the above-mentioned flat particles are typically and efficiently exhibited.

[0038]

【The invention's effect】

(Effect of the first invention) The light-scattering type light control device of the first invention has both a memory property and a high-speed response property.

(Effect of the Second Invention) In addition to the effect of the light control element of the first invention, the light control element of the second invention can achieve multicolor control of the light control element, and further, The dimming contrast can be further increased.

(Effect of the third invention) The light control element of the third invention provides, in addition to the effects of the first and second inventions, a few effective memory state releasing means in the light control element.

(Effect of Fourth Invention) In addition to the effects of the first invention to the third invention, the light control element of the fourth invention can be used for a wider range of applications, and its durability can be improved. it can.

(Effect of Fifth Invention) In addition to the effects of the first invention to the fourth invention, the light control element of the fifth invention can further improve the high-speed response of the light control element.

(Effect of Sixth Invention) In addition to the effects of the first to fifth inventions, the dimming element of the sixth invention can further increase the dimming contrast between when voltage is applied and when voltage is not applied. it can.

(Effect of Seventh Invention) In addition to the effects of the first invention to the sixth invention, the light control element of the seventh invention can exhibit various actions of flat particles typically and efficiently. it can.

[0045]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the first invention to the seventh invention will be described.

(Embodiment of Hollow Cell) In the hollow cell, at least the light transmitting portion is colorless or colored and transparent.
Therefore, if the light control element is of a light transmission type, the front and rear walls of the cell along the light transmission direction are transparent, and if the light control element is of a light reflection type such as a display or a mirror. The wall of the light incident portion is transparent, while the wall of the light reflecting portion is opaque or light reflective.

In the first to seventh inventions, "transparent" does not necessarily mean an absolute transparent state, but "relatively allowed depending on the purpose of use of the light control element,
Or it is light-transmissive to the extent desired. " Therefore, the meanings of the terms "low light transmittance" and "opaque" are also relatively determined by the relationship with "transparent" in the above meaning, and it is not always the case that a perfect light-shielded state or a perfect Does not mean opaque.

The hollow portion for filling the liquid crystal composition in the cell needs to have a gap having an appropriate width in the light transmitting direction. The width of the gap is variously required depending on the purpose of use of the light control element and the size of the domain formed in the liquid crystal composition, but for example, a gap of several μm to several tens of μm or the number of domain diameters. It can be set to about double.

The expansion of the hollow portion of the cell (size in the direction perpendicular to the light incident direction) is not limited. For example, it may have a large size corresponding to the window glass of an automobile. The cell may be formed to have a large spread as a whole, and may be divided into a large number of small subcells by partition walls. In that case, the whole cell is 1
Even if it is covered with a pair of large electrodes, it has the effect of preventing leakage of the liquid crystal composition when the cell is damaged,
Further, when the electrodes that can be turned on and off individually are provided for each individual subcell or for each fixed number of subcell groups, different light transmittance can be set for each cell part. Except for the above points, there is no limitation on the constituent material, shape, and size of the cell or its hollow portion.

(Embodiment of Liquid Crystal) The liquid crystal used in the light control device of the first invention to the seventh invention is mainly composed of liquid crystal molecules having electric field response and positive dielectric anisotropy. As typical examples of such liquid crystal molecules, for example, the following "Chemical formula 1" to "Chemical formula 1"
Liquid crystal molecules listed as “7”,
Cholesteric liquid crystal molecules listed as “Chemical Formula 26”,
There are smectic liquid crystal molecules shown as "Chemical Formula 27" and "Chemical Formula 28".

Among the liquid crystal molecules shown in "Chemical Formula 1" to "Chemical Formula 28" above, in "Chemical Formula 1", n is an integer of 3 to 8, and in "Chemical Formula 2", n is an integer of 4 to 8. In Chemical formula 3, n is an integer of 6 to 8, and in Chemical formula 4, n is 3.5 to 5.
An integer of 8 or 10, n in "Chemical formula 5"
Is an integer of 3, 5, 7, 9, and 10, n in "Chemical formula 6" is any integer of 3, 4, 6, 7, and n is 3,4 in "Chemical formula 7" , 6, 8 and n in “Chemical formula 8”, n is any integer in 2 to 4, and in “Chemical formula 9” n is any integer in 2 to 7, 10 ", n is an integer of 3, 5", "Chemical 13" is an integer of 5, 7, and "Chemical 14" is an integer of 4, 6 An integer, where n is 4, 6, 8 in "Ka 15"
Any of the integers, n is 6 in “Chemical 16”,
In "Chemical formula 17", n is an integer of 3 or 5, "Chemical formula 27" is an integer of 8 to 12, and "Chemical formula 28" is an integer of 8 to 12. is there.

[0052]

[Chemical 1]

[0053]

[Chemical 2]

[0054]

[Chemical 3]

[0055]

[Chemical 4]

[0056]

[Chemical 5]

[0057]

[Chemical 6]

[0058]

[Chemical 7]

[0059]

[Chemical 8]

[0060]

[Chemical 9]

[0061]

[Chemical 10]

[0062]

[Chemical 11]

[0063]

[Chemical 12]

[0064]

[Chemical 13]

[0065]

[Chemical 14]

[0066]

[Chemical 15]

[0067]

[Chemical 16]

[0068]

[Chemical 17]

[0069]

[Chemical 18]

[0070]

[Chemical 19]

[0071]

[Chemical 20]

[0072]

[Chemical 21]

[0073]

[Chemical formula 22]

[0074]

[Chemical formula 23]

[0075]

[Chemical formula 24]

[0076]

[Chemical 25]

[0077]

[Chemical formula 26]

[0078]

[Chemical 27]

[0079]

[Chemical 28]

Liquid crystal molecules having a small value even if the dielectric anisotropy is positive, or liquid crystal molecules having a negative dielectric anisotropy, that is,
For example, the liquid crystal molecules listed below as “Chemical formula 29” to “Chemical formula 57” have positive dielectric anisotropy as a result of being mixed with the liquid crystal molecules composed of the liquid crystal molecules of “Chemical formula 1” to “Chemical formula 28”. If you show, you can use without any problem.

Regarding the liquid crystal molecules of “Chemical formula 29” to “Chemical formula 57”, in “Chemical formula 29”, n is an integer of 1 to 3 and n
When 1 is 1, m is an integer of 3 to 6, when n is 2, m is an integer of 4, 6, and when n is 3, m is 8. Is a combination of n = 1 and m = 5, or a combination of n = 6 and m = 4, and in the formula 36, a combination of n = 1 and m = 6, or n = 5 m is one of the combinations of 8,
In “Chemical 38”, the combination of n = 1 and m = 5,
Either n is 6 and m is 9, and
3 ”, n is an integer of 4 or 5, and when n is 4, m is an integer of 4, 6, or 7, and n is 5
When m is 5, when n is any integer of 3 to 5 in "Chemical formula 44", when n is 3, m is any integer of 2, 4 and n is 4 or 5 The hour m is an integer of 2 or 5.

[0082]

[Chemical 29]

[0083]

[Chemical 30]

[0084]

[Chemical 31]

[0085]

[Chemical 32]

[0086]

[Chemical 33]

[0087]

[Chemical 34]

[0088]

[Chemical 35]

[0089]

[Chemical 36]

[0090]

[Chemical 37]

[0091]

[Chemical 38]

[0092]

[Chemical Formula 39]

[0093]

[Chemical 40]

[0094]

[Chemical 41]

[0095]

[Chemical 42]

[0096]

[Chemical 43]

[0097]

[Chemical 44]

[0098]

[Chemical formula 45]

[0099]

[Chemical formula 46]

[0100]

[Chemical 47]

[0101]

[Chemical 48]

[0102]

[Chemical 49]

[0103]

[Chemical 50]

[0104]

[Chemical 51]

[0105]

[Chemical 52]

[0106]

[Chemical 53]

[0107]

[Chemical 54]

[0108]

[Chemical 55]

[0109]

[Chemical 56]

[0110]

[Chemical 57]

The liquid crystal phase of the liquid crystal molecule is preferably a nematic or cholesteric one because it generally has a high electric field response, but a smectic one is also preferable. Any device that exhibits electric field response as shown in can be used.

Among liquid crystals having electric field responsiveness and positive dielectric anisotropy, use should be made of a liquid crystal which causes a phase change between a liquid crystal state and an isotropic state in a temperature range where a normal light control element is commonly used. However, it is more preferable because the applications of the light control element can be expanded and the durability thereof can be improved. It is difficult to uniformly define such a temperature range because it depends on the use of the light control element, but in general, it is -10 to 6
It is considered to be in the range of 0 ° C or in the vicinity thereof. Most of the liquid crystals composed of the liquid crystal molecules listed in "Chemical Formula 1" to "Chemical Formula 57" or a mixture of two or more of these liquid crystals are included in the above temperature range.

In the invention of the present application, among the liquid crystals having electric field response and positive dielectric anisotropy, the liquid crystal state and the isotropic state are partially or completely out of the normal temperature range. It goes without saying that a liquid crystal that causes a phase change of can also be used.

Among liquid crystals having electric field responsiveness and positive dielectric anisotropy, when liquid crystal molecules having a low molecular weight are used, the electric field response speed of the light control element is increased, and eventually, the electric field response is improved. It is more preferable because the threshold voltage can be set low. The low molecular weight referred to in the present invention differs depending on the chemical structure of liquid crystal molecules, but means, for example, one having a molecular weight of 1000 or less. As examples of such liquid crystal molecules, many of the liquid crystal molecules listed in the above-mentioned "Chemical formula 1" to "Chemical formula 57" can be mentioned.

In the present invention, it is needless to say that among the liquid crystals having electric field response and positive dielectric anisotropy, those in which liquid crystal molecules are not low molecular weight molecules can be used.

As the liquid crystal, one kind may be used alone, or a mixture of two or more kinds of liquid crystals may be used. However, in general, the latter is preferable because it is easy to form a liquid crystal phase in a wide temperature range. As an example of mixed liquid crystal,
60 mol% of the liquid crystal of "Chemical Formula 29" (where n is 1 and m is 4)
And 40 mol% of the liquid crystal of “Chemical Formula 29” (n is 2 and m is 4).

(Embodiment of Flat-Shaped Particles) “Flatness” of the flat-shaped particles dispersed in the liquid crystal composition means that the aspect ratio of the particles is large to some extent, and the flat-shaped particles can be efficiently dispersed in the liquid crystal composition. To form the domain of structure,
Generally, it is desirable that the aspect ratio is 2 or more, and more preferably 5 or more. The shape of the particles is not limited to the plate shape, and may be a rod shape or a needle shape.

The material forming the flat particles is not limited. However, it is preferable that the flat particles are particles that change their own orientation by an electric field, because the changes in the orientation occur clearly and quickly, and the above-mentioned actions and effects are clearly generated.

Preferable examples of flat particles which undergo orientation change by an electric field are layered clay minerals, titanium oxide, alumina white (water-insoluble basic aluminum sulfate), calcium carbonate, flaky zinc oxide, and flaky aluminum powder. , Navy blue, hematite oxide, plate-like crystals of various ceramics, graphite and the like. Furthermore, organic crystals, organic metal complexes, and the like can also be used. Particles that do not change their orientation by an electric field can also be used in the present invention. Examples of particles having little or no electric field response include particles made of organic polymers such as polyethylene, polypropylene, and polytetrafluoroethylene.

On the other hand, in order to keep the response speed of the liquid crystal composition equal to the response speed of the liquid crystal itself, the flat particles interact with the liquid crystal molecules only through the interface and have little influence on the internal viscosity of the liquid crystal. It is preferably one.

Taking the above requirements into consideration, the layered clay mineral is most preferable as the material used for the flat particles. As the layered clay mineral, natural or synthetic montmorillonite, saponite, mica, hectorite, or the like can be used, but montmorillonite is typical because it is relatively easily dispersed in liquid crystal.

The particle size of the flat particles is 0.1 to 20 μm.
m is suitable. If the particle size is smaller than this range, there is a problem that the domains in the liquid crystal composition cannot be effectively formed. When the particle size is larger than this range, nonuniformity of the liquid crystal composition becomes conspicuous when a dimming element is formed, causing an appearance defect, and a hollow cell having a cell gap of several tens of micrometers is formed. In that case, the orientation may be insufficient due to physical restrictions of the cell gap. Particularly preferred range of particle size is 0.2-5
μm. It is easy to prepare layered clay minerals in these appropriate particle size ranges.

The flat particles are preferably dispersed in a density such that the liquid crystal domains are effectively formed. On the other hand, it is not preferable that the density of the flat particles is too high and the changes in their orientations are bound to each other. The density that simultaneously meets these requirements varies depending on the type of liquid crystal or the type and size of flat particles, and it is difficult to uniformly define the density.
It is desirable to disperse 1 to 10 parts by weight of flat particles with respect to 0 part by weight. This range also applies when the flat particles are layered clay minerals.

It is not always necessary for the flat particles to be dispersed in the liquid crystal so that the individual particles are completely dispersed. Even if some of the particles are agglomerated, It suffices that the flat particles as a whole are dispersed to the extent that the above-mentioned actions and effects are exhibited. For example, layered clay minerals often exist in a state of being dispersed in liquid crystal, with some dozens of individual particles (unit layers) overlapping each other, but the above-mentioned action of sufficiently flat particles is still observed.・ Effects are played.

In order to maintain at least the dispersion state as described above, the flat particles are required to have affinity with the liquid crystal. If the flat particles are made of a material that originally has an affinity for liquid crystals, such as some organic crystals or organic metal complexes, they may be used as they are.
However, if the flat particles are made of a material that does not inherently have an affinity for liquid crystals, such as particles made of an inorganic substance such as a layered clay mineral, it should have an affinity for liquid crystals. Processing is required. An example of such a treatment is generally a treatment of adsorbing or binding an organic substance on the surface of particles.

Especially when the flat particles are layered clay minerals, it is effective to carry out ion exchange in order to impart affinity to the liquid crystal. That is, since alkali metal ions exist between the layers of the layered clay mineral, they are exchanged with organic onium ions having an affinity for liquid crystal molecules or onium ions having a liquid crystal group (so-called organizing) to form liquid crystals. Can have an affinity of.

Since the type of the onium ion is preferably one having excellent affinity with the liquid crystal molecules, the most suitable one is selected according to the type of the liquid crystal molecules to be used. For example, an alkylammonium ion is typical. is there. It should be noted that there is an advantage that the surface properties, electrical and optical properties, dispersibility, responsiveness to an electric field, etc. of the layered clay mineral can be variously controlled by selecting the organic onium ion.

In preparing the composition of the liquid crystal and the flat particles having an affinity for the liquid crystal, it is sufficient to simply mix the two. However, if both are uniformly mixed using a common solvent and then the common solvent is removed by an appropriate means, more uniform mixing is achieved. The same is true when preparing a composition of liquid crystal and an organized layered clay mineral.

(Embodiment of Dichroic Dye) As the dichroic dye contained in the liquid crystal composition of the present invention, any dichroic dye can be used as long as its spectral change is suitable for its use. The molecular shape and crystal shape are not particularly limited, but for the same reason as in the case of the flat particles, those having an aspect ratio of a certain degree or more, such as rod-like particles, are more preferable.

As examples of the dichroic dye, the azo dichroic dyes shown in "Chemical Formula 58" to "Chemical Formula 77" and "Chemical Formula 78" to "Chemical Formula 8"
1 ”, an azomethine dichroic dye represented by“ Chemical Formula 82 ”, a styryl dichroic dye represented by“ Chemical Formula 82 ”, an anthraquinone type dichroic dye represented by“ Chemical Formula 83 ”to“ Chemical Formula 86 ”, and a tetrazine type compound represented by“ Chemical Formula 87 ”. Examples thereof include dichroic dyes and merocyanine-based dichroic dyes shown in “Chemical Formula 88”.

[0131]

[Chemical 58]

[0132]

[Chemical 59]

[0133]

[Chemical 60]

[0134]

[Chemical formula 61]

[0135]

[Chemical formula 62]

[0136]

[Chemical formula 63]

[0137]

[Chemical 64]

[0138]

[Chemical 65]

[0139]

[Chemical formula 66]

[0140]

[Chemical formula 67]

[0141]

[Chemical 68]

[0142]

[Chemical 69]

[0143]

[Chemical 70]

[0144]

[Chemical 71]

[0145]

[Chemical 72]

[0146]

[Chemical formula 73]

[0147]

[Chemical 74]

[0148]

[Chemical 75]

[0149]

[Chemical 76]

[0150]

[Chemical 77]

[0151]

[Chemical 78]

[0152]

[Chemical 79]

[0153]

[Chemical 80]

[0154]

[Chemical 81]

[0155]

[Chemical formula 82]

[0156]

[Chemical 83]

[0157]

[Chemical 84]

[0158]

[Chemical 85]

[0159]

[Chemical 86]

[0160]

[Chemical 87]

[0161]

[Chemical 88]

Regarding the mode in which the dichroic dye is contained in the liquid crystal, a dichroic dye compatible with the liquid crystal is typically dissolved in the liquid crystal.

However, irrespective of whether or not the dichroic dye is compatible with the liquid crystal, the dichroic dye is adsorbed to the flat particles, or if the flat particles are layered clay minerals, the onium group is used. It may be an effective mode to intercalate a dichroic dye having γ by ion exchange between the layers of the layered clay mineral. In these cases, the orientation of the dichroic dye is controlled by the orientation of the flat-shaped particles or the orientation of the layered clay mineral, so that the dichroic dye is oriented in the long axis direction of the flat-shaped particles or the layered clay mineral. Are required to be adsorbed or intercalated in parallel or substantially parallel to each other.

Of the above-mentioned three modes for containing the dichroic dye in the liquid crystal, only one mode may be selectively carried out, and any two or more modes are simultaneously carried out. It may be.

(Embodiments for Other Compositions) The liquid crystal composition used in the light control device of the present invention does not impair the object of the present invention in addition to the above liquid crystal, flat particles and dichroic dye. As long as it is possible, a known liquid crystal or any component that may be contained in a liquid crystal composition can be included according to a known method. Examples of such components include liquid crystal modifiers such as stabilizers, viscosity modifiers such as thickeners and viscosity reducers, organic onium salts and the like.

(Embodiment of Electric Field Applying Means) The electric field applying means is a means which can apply an electric field to the liquid crystal composition filled in the cell of the light control element, and is usually a pair of electrodes. In the present invention, since a liquid crystal having a positive dielectric anisotropy is used as the liquid crystal of the liquid crystal composition, the pair of electrodes is installed on the opposing wall portion located in the light incident direction in the hollow cell. In addition, it is possible to install a pair of electrodes on opposing walls located vertically above the light incident direction in the hollow cell, and use a liquid crystal having a negative dielectric anisotropy as the liquid crystal of the liquid crystal composition. However, in this case, new technical problems such as the problem of the distance between electrodes when the cell is configured to be wide and the problem of orientation control when flat particles have an electric field response are considered. Create challenges.

The electrodes may be constructed so that an electric field can be effectively applied to the entire cell and they do not interfere with the transmission or reflection of light rays. Usually, a transparent whole surface electrode covering the whole liquid crystal composition filling portion in a hollow cell is used. In this case, for example, IT is used.
An O (indium tin oxide) electrode attached to a glass plate or the like forming the cell wall is used. However, even in this case, when the light control element is of a light reflection type, the electrode provided on the reflection side wall portion does not need to be transparent.

(Embodiment of Memory State Releasing Means) The memory state releasing means is a means having a function of eliminating domains formed in the liquid crystal composition. There is a means for controlling the temperature of the liquid crystal composition as the first memory state releasing means, and a means for applying a shearing force to the liquid crystal composition as the second memory state releasing means.

As a means for controlling the temperature of the liquid crystal composition, for example, a transparent heating element can be attached to the wall of the cell, but the ease of assembly, the ease of temperature control and the control speed are preferable. Other appropriate temperature control means may be used as long as the above is satisfied. Alternatively, the liquid crystal composition may contain an electrolyte at a predetermined concentration, and the liquid may be energized to serve as the temperature control means. The means for lowering the temperature of the liquid crystal composition heated to the isotropic temperature to the liquid crystal temperature may be left to cool, or an appropriate cooling means may be provided.

The means for imparting shear force to the liquid crystal composition is most effective for imparting a shear to the liquid crystal composition.
I believe. An example of the specific embodiment is simplified and shown in FIG. The point of the embodiment shown in FIG. 3 is that one of the wall portions constituting the cell of the light control element is configured to be slidable in the horizontal direction.

That is, the cell is constructed by arranging a pair of transparent glass plates 4 with ITO electrodes in a facing state with a certain gap through a spherical spacer 5 acting as a roller. A rubber sealing member 6 is fixed along the edge of the glass plate 4 to prevent leakage of the liquid crystal composition 7 sealed in the gap. An actuator 8 is linked to one of the glass plates 4, and the glass plate 4 is driven by the actuator 8 to slide in the direction of arrow A in the figure, whereby the liquid crystal composition enclosed in a thin layer is formed. Shearing force is applied to the object 7. The actuator 8 may have any structure as long as it drives the glass plate 4 as described above. For example, when importance is attached to responsiveness or accuracy of the displacement momentum, the actuator 8 is driven by magnetic force. A type of reciprocating an iron core for use, a type of using a piezoelectric element as a driving material, and the like are possible.

As other means for imparting a shearing force to the liquid crystal composition, a striking member for impacting the cell, a means for imparting ultrasonic vibration to the liquid crystal composition filled in the cell, or a liquid crystal composition filled in the cell may be used. Means for applying frequency vibration may be considered.
There is no limitation on the specific configuration of these means, and various known methods can be used.

[0173]

EXAMPLES Examples of the first to seventh inventions of the present application will be described below.

Example 1 Preparation of Organized Montmorillonite 200 g of high-purity Na-montmorillonite (ion exchange capacity: 119 meq / 100 g) obtained from bentonite produced in Yamagata prefecture was dispersed in 3,500 ml of water, and °
Heated to C. On the other hand, laurylamine 48.8 g (26
2 mmol), water and concentrated hydrochloric acid (31.0 g) were added, and the mixture was heated and stirred to completely dissolve it. The Na-montmorillonite-
When this ammonium salt solution was added to the aqueous dispersion with vigorous stirring, aggregates were formed, but the stirring was continued for another 30 minutes. After the completion of stirring, the aggregate was collected by filtration, washed once with ethanol, washed with hot water three times, freeze-dried, and dried under vacuum at 80 ° C for 5 hours, and then organized with lauryl ammonium ion. The powdered montmorillonite (hereinafter referred to as "lauryl ammonium montmorillonite") was obtained.

Preparation of Liquid Crystal Composition 1 ml of 1.0 g of 4-pentyl-4′-cyanobiphenyl liquid crystal (phase transition temperature between isotropic phase and liquid crystal phase: 35 ° C.)
Dissolved uniformly in dimethylacetamide, and 0.01
24 g of lauryl ammonium montmorillonite (inorganic content 0.0108 g) was uniformly dispersed in 2 ml of dimethylacetamide, and these solutions and dispersions were uniformly mixed. Then, dimethylacetamide was heated under vacuum (5
After evaporating to 0-60 ° C), thoroughly stir and mix,
A white paste liquid crystal composition was obtained.

Polarizing Microscope Observation Polarizing microscope Model BHS manufactured by Olympus Optical Co., Ltd.
Using -P, the liquid crystal composition in the isotropic state was observed under crossed nicols to measure the approximate dispersed particle size of lauryl ammonium montmorillonite in the liquid crystal composition. The results are shown in Table 1.

[0177]

[Table 1]

Manufacture of Light Control Element The light control element shown in FIG. 3 was manufactured. In this light control element, an ITO electrode (resistance value 100 Ω / cm ² ) having a thickness of 1 mm and a length of 500 mm and a width of 500 mm was attached to the entire inner surface of each pair of glass plates 4, and the I
The TO electrode is connected to a 60 Hz AC power supply. The glass plate 4 with the ITO electrode has high transparency, and its light transmittance is about 97%. Spacer 5 has a diameter of 12μ
m polymer beads were used. Therefore, the cell gap is 12 μm. In addition, the liquid crystal composition 7 enclosed in the cell
Was sealed with a sealing member 6 made of a two-component curing type silicone rubber.

Although not shown, the following electromagnetic actuator was used as the actuator 8. That is, an iron core around which a coil is wound is fixed to one end of one glass plate 4, and a permanent magnet is arranged so as to surround the iron core. When an AC electric field is applied to the coil, the iron core acts as an electromagnet, and the iron core vibrates in the direction of arrow A in the figure due to attractive force and repulsive force between the iron core and the permanent magnet. A shearing force is applied to the liquid crystal composition 7 by this vibration. In each of the following examples, when the electromagnetic actuator was made to act on the liquid crystal composition actually in the memory state, the memory state of the liquid crystal composition was instantaneously (1
It was canceled for about 0 millisecond) and returned to the initial light scattering state.

Measurement of Light Transmittance FIG. 4 shows a schematic diagram of an apparatus system configured for measuring the light transmittance of the light control element. In the apparatus shown in FIG. 4, the optical system includes a polarization microscope 11 (Model B manufactured by Olympus Optical Co., Ltd.).
The HS-P polarization microscope was used with the polarizing plate removed), and as the light source 12, a halogen lamp attached to the polarization microscope 11 was used. Light transmission is R-1 made by Hamamatsu Photonics
It was detected by a photomultiplier tube 547 (Photomul 13).

The current output from the Photomul 13 is 200 k.
It was converted into a voltage by connecting a resistance of Ω in series and read with a pen recorder. The recording results with this pen recorder are shown in FIG. 5 and Table 1. In FIG. 4, a C448A manufactured by Hamamatsu Photonics was used as the high-voltage DC voltage power supply for Photomaru, and a multimeter TR6355 manufactured by Takeda Riken was used as the voltmeter. The voltage was applied to the cell by adjusting a 100 V AC power source (60 Hz) to 0 V, 20 V, 40 V, 60 V and 80 V through a slider box.

Releasing the memory state Among the above, for the light control element in which the voltage of 60 V is applied and then the voltage is released to maintain the memory state, an AC electric field of 60 Hz is applied to the electromagnetic actuator for 50 ms,
When a shearing force was applied to the liquid crystal composition, the memory state was released almost instantaneously. Table 1 shows the light transmission amount after the memory state is released.

Further, the cell of the light control element was observed under a polarization microscope to observe the orientation change of lauryl ammonium montmorillonite by the application of an electric field. The observation results corresponded to the orientation change of the flat-shaped particles shown in FIG.

Response speed Ultra-sensitive multi-photometer system I manufactured by Otsuka Electronics Co., Ltd.
The response speed of the light control device was measured using MUC-7000. The measurement conditions are as follows: sampling time 10 ms, interval time 0 ms, measurement wavelength 572 nm,
A voltage 70 V-60 Hz was instantaneously applied to measure the time change of the Photomul output, and the time required for the output to change to 90% of the equilibrium value was defined as the response time. FIG. 6 shows a time change curve of the photomultiplier output. Here the sampling time is 1
Since it is 0 ms, the response time measured this time has an error of about ± 5 ms.

Transmission X-ray Diffraction Measurement The transmission X-ray diffraction measurement was performed on the liquid crystal composition using a rotating anticathode type X-ray diffractometer (RU-Z type) manufactured by Rigaku Denki Co., Ltd. The measurement conditions are as follows. Tube: Co-Kα Tube voltage: 40 KV Tube current: 150 mA Slit: DS, 0.05 mm RS, 0.15 mm SS, 1 ° CS, 0.55 mm The sample is a conductive film manufactured by Toray Industries, Inc. The liquid crystal composition prepared in Example 3 described later was enclosed between certain high beams (made of polyester and having a thickness of 100 μm) via a spacer of 25 μm. The orientation change of the layered clay mineral in the initial state and the state (memory state) in which the electric field was cut off after applying the electric field (100 V-60 Hz) was measured by (00
1) It was investigated by observing a change in peak intensity derived from the plane.

FIG. 7 shows the result of the above-mentioned transmission type X-ray diffraction measurement. (A) in the figure is a diffraction pattern in the state before applying an electric field (initial state), and (b) in the figure shows 10
It is a diffraction pattern in the state of turning off the electric field (memory state) after applying the electric field of 0 V-60 Hz. From FIG. 7, the peak based on the (001) plane reflection of montmorillonite (corresponding to the interlayer distance of montmorillonite) is small in the initial state, whereas the peak based on the (001) plane reflection is large in the memory state. I understand. From these results, it can be seen that when an electric field is applied, the orientation of the montmorillonite layer surface changes parallel to the direction of the applied electric field. This result agrees with the change in orientation of the flat particles shown in FIG.

Example 2 1.0 g of 4-pentyl-
0.0252 g of lauryl ammonium montmorillonite (inorganic content: 0.
The same measurement as in Example 1 was carried out except that 0205 g) was used. Table 1 shows the results of each measurement.
Shown in. The observation of the orientation change of lauryl ammonium montmorillonite under a polarizing microscope and the result of the transmission X-ray diffraction measurement were the same as in Example 1.

Example 3 1.0 g of 4-pentyl-
0.0382 g of lauryl ammonium montmorillonite (inorganic content of 0.
The same measurement as in Example 1 was carried out except that 0311 g) was used. Table 1 shows the results of each measurement.
Shown in. The observation of the orientation change of lauryl ammonium montmorillonite under a polarizing microscope and the result of the transmission X-ray diffraction measurement were the same as in Example 1.

Example 4 1.0 g of 4-pentyl-
0.0516 g of lauryl ammonium montmorillonite (inorganic content of 0.
The same measurement as in Example 1 was carried out except that 0421 g) was used. Table 1 shows the results of each measurement.
Shown in. The observation of the orientation change of lauryl ammonium montmorillonite under a polarizing microscope and the result of the transmission X-ray diffraction measurement were the same as in Example 1.

(Example 5) 4- (4- (N-phthalimido) butoxy) -4'-si
Synthesis of anobiphenyl 4-cyano-4'-hydroxybiphenyl 10.5 g (54 mmol), anhydrous potassium carbonate 18.8 g (136 mmol), and acetone- in a 250 ml flask.
Dimethyl sulfoxide mixed solvent (125: 12) 137
ml was added, and the mixture was heated to the reflux temperature under a nitrogen atmosphere and stirred for about 2 hours and 20 minutes. Then, 15.2 g (54 mmol) of N- (4-bromobutyl) phthalimide was added,
Further, stirring was continued at the reflux temperature for about 17 hours. The obtained reaction mixture was put into 500 ml of water, stirred for a while, and the water-insoluble portion was collected by suction filtration. The slightly yellow powder thus obtained was dried under vacuum, then dissolved in chloroform, and subjected to a column method (a packing material was silica gel,
4- (4- (N-phthalimido) butoxy) -4'-cyanobiphenyl was separated and purified with chloroform as a solvent to obtain a white powder thereof. This white powder was recrystallized from a mixed solvent of ethanol-chloroform (300: 200) to obtain 14.1 g of needle-shaped white crystals (yield 66.0%).

4- (4-aminobutoxy) -4′-sia
Synthesis of nobiphenyl 4- (4- (N-phthalimide) was added to a 250 ml flask.
Butoxy) -4'-cyanobiphenyl (13.9 g) was dissolved in tetrahydrofuran (120 ml) and heated to 50 ° C. Hydrazine monohydrate in this solution 11.
08 g (221 mmol) and 50 ml of ethanol were added, and the mixture was stirred at reflux temperature for about 4 hours. Then, after cooling to room temperature, 40 ml of concentrated hydrochloric acid was slowly added. The reaction mixture was extracted with 300 ml of chloroform and an aqueous solution of sodium hydroxide (50 g of sodium hydroxide-120 ml of water), and the organic phase was washed with 300 ml of water three times. Next, the organic phase was dried over anhydrous sodium sulfate, the desiccant was filtered off, and then the solvent was distilled off using a rotary evaporator to obtain a yellow viscous liquid. This liquid was separated and purified by a column method (silica gel as a packing material, chloroform-ethanol = 1: 1 as a solvent) to give 4- (4-aminobutoxy) -4′-cyanobiphenyl as a pale yellow solid 5.5.
7 g (yield 60.0%) was obtained.

Synthesis of Organized Montmorillonite 6.31 g of high-purity Na-montmorillonite (ion exchange capacity: 119 meq / 100 g) obtained from bentonite produced in Yamagata Prefecture was dispersed in 400 ml of water. on the other hand,
2.20 g of 4- (4-aminobutoxy) -4'-cyanobiphenyl was dissolved in 50 ml of ethanol, and 0.836 g of concentrated hydrochloric acid was added to this solution to prepare an ammonium salt.
At this time, a part of the ammonium salt was crystallized and precipitated, but it could be dissolved by adding 10 ml of water. When the Na-montmorillonite-water dispersion was added to this solution with vigorous stirring, aggregates were formed, but stirring was continued for another 20 minutes.

After the completion of stirring, the aggregate was collected by filtration,
After washing with ethanol once and washing with hot water three times, it was freeze-dried, dried under vacuum at 80 ° C. for 5 hours, and powdered montmorillonite organized with cyanobiphenyloxybutylammonium ion (hereinafter, “ "Cyanobiphenyloxybutyl ammonium montmorillonite".)
Got

Preparation of liquid crystal composition 1.0 g of 4-pentyl-4'-cyanobiphenyl liquid crystal was uniformly dissolved in 1 ml of dimethylsulfoxide, and 0.0128 g of cyanobiphenyloxybutylammonium montmorillonite (inorganic content 0.0096 g ) Was uniformly dispersed in 2 ml of dimethylacetamide, and these solutions and dispersions were uniformly mixed. Then, the dimethylacetamide was removed by evaporation under vacuum heating (50 to 60 ° C.), and then sufficiently stirred and mixed to obtain a white paste liquid crystal composition.

Using the above liquid crystal composition, in the same manner as in Example 1, observation with a polarizing microscope, preparation of a light control element, measurement of light transmission amount, measurement of response speed, transmission X-ray diffraction measurement, memory state releasing operation. The light transmission amount after releasing the memory state and its response speed were measured. The measurement results are shown in Table 1. The observation of the orientation change of lauryl ammonium montmorillonite under a polarizing microscope and the result of the transmission X-ray diffraction measurement were the same as in Example 1.

Example 6 The same procedure as in Example 5 was carried out except that 0.0250 g of cyanobiphenyloxybutylammonium montmorillonite (inorganic content 0.0190 g) was used, and the same measurements as in Example 5 were carried out. The results of each measurement are shown in Table 2. The observation of the orientation change of lauryl ammonium montmorillonite under a polarizing microscope and the result of the transmission X-ray diffraction measurement were the same as in Example 1.

[0197]

[Table 2]

(Example 7) The same measurement as in Example 5 was carried out in the same manner as in Example 5 except that 0.0382 g of cyanobiphenyloxybutylammonium montmorillonite (inorganic content of 0.0288 g) was used. The results of each measurement are shown in Table 2. The observation of the orientation change of lauryl ammonium montmorillonite under a polarizing microscope and the result of the transmission X-ray diffraction measurement were the same as in Example 1.

Example 8 The same procedure as in Example 5 was carried out except that 0.0531 g of cyanobiphenyloxybutylammonium montmorillonite (inorganic content 0.0400 g) was used, and the same measurements as in Example 5 were carried out. The results of each measurement are shown in Table 2. The observation of the orientation change of lauryl ammonium montmorillonite under a polarizing microscope and the result of the transmission X-ray diffraction measurement were the same as in Example 1.

Comparative Example 1 The contents of the liquid crystal cell in Example 1 were changed to the liquid crystal composition used in Example 1 except that 4-pentyl-4′-cyanobiphenyl liquid crystal was enclosed alone. The same measurement as in Example 1 was performed, and the same measurement as in Example 1 was performed. The results of each measurement are shown in Table 2.

(Comparative Example 2) Liquid crystal light control sheet PDLC film made by Nippon Sheet Glass Co., Ltd. (cell gap 22μ
Table 2 lists the catalog data for m).

(Comparative Example 3) Vol.
112, No. 4, P28 (1992), Kajiyama et al.'S article "Functionalization of Liquid Crystal Polymers and Perspective of Application" is cited in Table 2 as reference data on low molecular weight liquid crystal-polymer liquid crystal composites.

(Evaluation of Examples 1 to 8 and Comparative Examples 1 to 3) From Tables 1 and 2, the applied voltage was 0 in the light control element of each Example.
In the initial state of V, it becomes an opaque light-scattering state, and then when a predetermined electric field is applied, it becomes a transparent light-transmitting state. It is maintained and shows memory. Such characteristics are extremely clear in comparison with Comparative Example 1.

Regarding the response speed when an electric field was applied, the degree of decrease was extremely small even when compared with Comparative Example 1 in which liquid crystal was used alone, and the low-molecular liquid crystal-polymer liquid crystal composite of Comparative Example 3 was used. Compared with the response speed in the case of the body, the response speed is incomparably high. In any of the examples, when the liquid crystal cell is externally subjected to vibration, shock, or shear shear, the liquid crystal cell is initially brought into an initial state corresponding to (1) of FIG. When the temperature was raised above the point and then cooled, the state returned to the initial state corresponding to (5) in FIG.

Next, in any of the examples, when the operation for releasing the memory state was applied to the light control element, the initial light scattering state was returned almost instantly.

On the other hand, Comparative Example 1 applies an electric field,
It is transparent whether or not it does not show any light scattering state. In Comparative Example 2, it can be seen that the transparent state generated by applying the electric field is not maintained when the electric field is removed and has no memory property. Comparative Example 3 exhibits a sufficient memory property, but the response time is extremely long.

[Brief description of drawings]

FIG. 1 is a diagram showing an operation of the first invention of the present application.

2 (a) to 2 (e) are diagrams showing alignment states of liquid crystal molecules and flat particles corresponding to changes in the amount of light transmission in FIG.

FIG. 3 is a diagram showing a simplified example of a light control element.

FIG. 4 is a diagram showing a simplified system for measuring the amount of light transmission used in the examples.

FIG. 5 is a graph showing an example of measurement of electric field responsiveness to changes in light transmission amount in Examples.

FIG. 6 is a graph showing an example of measurement of an electric field response time of a liquid crystal cell in an example.

FIG. 7 is a graph showing a transmission type X-ray diffraction curve of the liquid crystal cell of the example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flat particle 2 Cell structure 3 Liquid crystal molecule 4 Glass plate 5 Spacer 6 Sealing member 7 Liquid crystal composition 8 Actuator

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Akane Okada Akane, Aichi Prefecture, Nagakute Town, Aichi Prefecture, Nagatoji, 1 41 Yokochi, Yokota Central Research Institute Co., Ltd.

Claims (7)

[Claims] 1. A hollow cell having at least a light-transmitting portion made of a transparent material, and a liquid crystal molecule filled in the cell and having electric field response and positive dielectric anisotropy as a main component. A liquid crystal composition comprising a liquid crystal and flat particles having an affinity for the liquid crystal, dispersed in such a density as to effectively form a domain of the liquid crystal, and the liquid crystal provided in the cell, Light scattering, comprising: an electric field applying unit capable of applying an electric field to the composition; and a memory state releasing unit attached to the cell and having a function of forming domains of the liquid crystal composition. Type light control element. 2. A hollow cell having at least a light-transmitting part made of a transparent material, and liquid crystal molecules filled in the cell and having electric field response and positive dielectric anisotropy as a main component. A liquid crystal containing a liquid crystal, a dichroic dye contained in the liquid crystal, and flat particles having an affinity for the liquid crystal dispersed in the liquid crystal at a density such that domains of the liquid crystal are effectively formed. A composition, an electric field applying means that is provided in the cell and can apply an electric field to the liquid crystal composition, and a memory state release function that is attached to the cell and has a function of forming domains of the liquid crystal composition A light-scattering type light control device comprising: 3. The memory state releasing means comprises one or more means of controlling the temperature of the liquid crystal composition or applying a shearing force to the liquid crystal composition. Claim 1 or claim 2
The light-scattering type light control element described in. 4. The liquid crystal according to claim 1, wherein the liquid crystal is a liquid crystal that causes a phase change between a liquid crystal state and an isotropic state in a temperature range in which a normal light control element is commonly used. The light-scattering type light control device as described in any one of items 5. The light scattering type light control device according to claim 1, wherein the liquid crystal molecules are low-molecular weight molecules. 6. The light-scattering type light control device according to claim 1, wherein the flat particles are particles showing an electric field response. 7. The light-scattering light control element according to claim 1, wherein the flat particles are organically modified layered clay minerals.