JP3427905B2 - Liquid crystal device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal encapsulating thin film which does not use a polarizing plate, and more particularly to a light scattering type liquid crystal device capable of electrically or thermally controlling the blocking and transmission of a visual field. INDUSTRIAL APPLICABILITY The liquid crystal device of the present invention is used as a screen for blocking a field of view in a window of a building, a show window, etc., and displays characters and figures, and switches the display electrically or thermally with high-speed response to display an advertising board. It can be used as a display device such as a decorative display board, a clock, a calculator, a display device that requires a bright screen, particularly a display device of a computer terminal or a display device of a projection.

[0002]

2. Description of the Related Art Conventionally, liquid crystal devices of TN (twisted nematic) type using nematic liquid crystal and STN (super twisted nematic) type have been put into practical use. Also, a liquid crystal device using a ferroelectric liquid crystal has been proposed. These require a polarizing plate and thus have a limit in brightening the screen, and require an alignment treatment, so that there is a problem that the yield at the time of manufacturing a display device is reduced.

On the other hand, as a method for producing a liquid crystal device which does not require a polarizing plate or an alignment treatment and is bright and has good contrast, a method is known in which liquid crystal droplets are dispersed in a polymer and the polymer is formed into a film. Tokusho Sho-501
631 and U.S. Pat. No. 4,435,047 describe gelatin, gum arabic, as encapsulating substances,
Polyvinyl alcohol, etc. have been proposed, and in addition to these,
For example, JP-A-61-502128 and JP-A-62.
It is known from Japanese Patent No. 2231. However, in the case of a liquid crystal device in which liquid crystal droplets are dispersed in a polymer, 25 V or more is required to obtain sufficient transparency in addition to the inconvenience of optimizing the matching / mismatching of the individual refractive indexes of the liquid crystal material and the polymer. Therefore, a high voltage was required, and it did not have the low drive voltage characteristics that are important in the practical application of the liquid crystal device for display.

JP-A-1-1987 discloses a technique that enables low-voltage drivability, high contrast, and time-division drivability, which are important characteristics required for practical use of liquid crystal display devices.
Japanese Unexamined Patent Publication No. 25 discloses a liquid crystal device having a structure in which a liquid crystal material forms a continuous layer and a polymer substance is distributed in a three-dimensional network in the continuous layer.

The characteristics required for such a liquid crystal device are a high resistance value and an excellent voltage holding ratio,
It is mentioned that the driving voltage is low, the light scattering is strong and the contrast ratio is large, and new proposals are being made even now. As a liquid crystal material for this purpose, for example, Japanese Patent Application No. 5-69946 discloses a method for optimizing the birefringence and the dielectric anisotropy of the liquid crystal material in European Patent No. 0359146.
The publication discloses a technique for specifying the elastic constant of a liquid crystal material.

[0006]

The problem to be solved by the present invention is to provide a liquid crystal device of the light scattering type as described above, which has a lower voltage drivability, a higher resistance value of the dimming layer, or a higher contrast. It is an object of the present invention to provide a light-scattering liquid crystal device that maintains and improves required display characteristics such as ratio and achieves more uniform white turbidity display.

[0007]

Means for Solving the Problems In order to obtain a more uniform white turbidity without unevenness, the present inventors have earnestly studied about a liquid crystal material and a transparent solid substance constituting a light control layer of a liquid crystal device, and as a result, The above problems have been solved.

That is, in order to solve the above problems, the present invention has a light control layer sandwiched between two transparent substrates, at least one of which has a transparent electrode layer, and the light control layer is a liquid crystal material. And a liquid crystal device containing a transparent solid substance, wherein the liquid crystal material comprises (a) general formula (I) and general formula (II)

[0009]

[Chemical 4]

(Wherein R ¹ and R ² are each independently (i)
A linear alkyl group having 2 to 5 carbon atoms, (ii) an alkenyl group having 2 to 5 carbon atoms, or (iii) 1 to 5 carbon atoms
Represents an alkoxyalkyl group in which a hydrogen atom of the alkyl group is substituted with an alkoxyl group having 1 to 5 carbon atoms,
X ^{1 to} X ⁴ each independently represent H or F. ) A compound selected from the first compound group represented by the formula (b) and (b) the general formulas (III) to (V)

[0011]

[Chemical 5]

(In the formula, R ³ is (i) a linear alkyl group having 2 to 5 carbon atoms, (ii) an alkenyl group having 2 to 5 carbon atoms, or (iii) 1 to 5 carbon atoms. Represents an alkoxyalkyl group in which the hydrogen atom of the alkyl group is substituted with an alkoxyl group having 1 to 5 carbon atoms, and R ⁴ is 2 to 8 carbon atoms.
Represents a linear alkyl group or an alkoxy group represented by R ⁵
Represents a linear alkyl group having 2 to 8 carbon atoms, and k and m each independently represent 0 or 1. And a liquid crystal device comprising a compound selected from the second compound group represented by Further, the liquid crystal material is represented by the general formula (VI)

[0013]

[Chemical 6]

(In the formula, R ⁶ represents a linear alkyl group having 2 to 7 carbon atoms, and R ⁷ represents a linear alkyl group having 1 to 7 carbon atoms or 1 to 7 carbon atoms. Represents a straight-chain alkoxy group, n represents an integer of 0 or 1, and Y
¹ represents a single bond, -COO- or represents -CH ₂ CH ₂ -, X ⁵ represents F or CH _3. And a liquid crystal device containing a compound selected from the third compound group represented by the formula (1).

The first invention of the liquid crystal device of the present invention is the first liquid crystal material represented by the general formulas (I) and (II) as a liquid crystal material showing high compatibility with a polymer-forming compound which forms a transparent solid substance. Has found a group of compounds. This transparent solid substance is preferably formed of a polymer-forming monomer and / or oligomer, and is prepared, for example, by mixing a thermosetting resin or an ultraviolet curable resin with a liquid crystal material. The higher compatibility of the polymer-forming compound and the liquid crystal material makes it possible to obtain a more uniform solution in a wider temperature range. By curing the polymer-forming compound in such a state, it is possible to prepare a light-modulating layer having a light-scattering property in a state where there is no deviation or little deviation.
It is possible to provide a light-scattering type liquid crystal device that achieves a display characteristic with uniform drive voltage and contrast ratio and achieves a more uniform white turbidity display. Therefore, for example, even if a liquid crystal material that exhibits a liquid crystal phase at a relatively high temperature shows a more uniform light-scattering property or a liquid crystal material that is relatively large, a liquid crystal material suitable for easier fabrication by a vacuum injection method is selected. I found it.

The compounds represented by the first compound group used in the liquid crystal device of the present invention have a dielectric anisotropy Δε of 15
It is in the range of 25 to 25 and has a fluorotolan structure. The representative compounds are shown in Table 1 below.

[0017]

[Table 1]

The higher compatibility with the polymer-forming compound is a peculiar phenomenon, as will be apparent from the examples described later. For example, the following compounds having a similar structure to the compounds represented by the first compound group do not show particularly high compatibility.

[0019]

[Chemical 7]

In the second invention of the present liquid crystal device, even if the compound represented by the first compound group contains the second compound group or the third compound group, the higher compatibility described above may be impaired. This is due to the fact that there is no or relatively small impact. Furthermore, it is useful for adjusting the dielectric anisotropy and elastic constant, and can improve the nematic phase of the liquid crystal material.

The compounds represented by the second compound group have a dielectric anisotropy Δε in the range of 10 to 20 and have a cyanophenyl group. Typical compounds are shown in Table 2 below. It was The compounds represented by the third compound group have a dielectric anisotropy Δε in the range of −1 to 2 and have a tolan structure, and representative compounds thereof are shown in Table 3 below.

[0022]

[Table 2]

[0023]

[Table 3]

Among these liquid crystal materials used in the present invention, a combination of a compound represented by the general formula (I) and a compound represented by the general formula (IV), or a combination of these compounds and a general formula ( A compound represented by II), a compound represented by the general formula (V) or a general formula (VI)
The combination with the compound represented by is preferable because it can increase the backscattering of the liquid crystal device.

Further, the combination of the compound represented by the general formula (I) and the compound represented by the general formula (VI), or the combination of these compounds with the compound represented by the general formula (III) is Since it is possible to reduce the impedance of each pixel of the liquid crystal device or the impedance of the entire liquid crystal device, the combination with a compound in which R ³ is an alkenyl group in the general formula (III) is preferable. It is particularly preferable because it can be effectively reduced.

In the specification of Japanese Patent Application No. 4-73959, the present inventors have shown that the relationship between the physical property value of the liquid crystal material and the display characteristic of the liquid crystal device is represented by the following formula (VII).

[0027]

[Equation 1]

(In the formula, Vth represents a threshold voltage, and ¹
Kii, ² Kii represents an elastic constant, i represents 1, 2 or 3, Δε represents a dielectric anisotropy, <r> represents an average void space of a transparent solid substance interface, and A represents a liquid crystal. It represents the anchoring energy of the transparent solid substance to the molecule, and d represents the distance between the substrates with transparent electrodes.

This formula means that the regulation force applied to the liquid crystal molecules by the transparent solid interface changes depending on the ratio of the elastic constant Kii and the anchoring energy A, and the effect is particularly the actual average void spacing <r. >, It has the effect of substantially expanding by the amount of Kii / A, thus effectively reducing the driving voltage.

This can also be applied to the present invention, and by selecting the dielectric constant anisotropy Δε and elastic constant of the liquid crystal material depending on the liquid crystal compound constituting the liquid crystal material, it is possible to drive at a low voltage. A preferable liquid crystal device can be obtained.

The total content of the compounds represented by the general formulas (I) and (II) in the liquid crystal material used in the liquid crystal device of the present invention is preferably in the range of 5 to 80% by weight.
The range of 0 to 80% by weight is particularly preferred.

The total content of the compounds represented by the general formulas (III) to (V) in the liquid crystal material used in the liquid crystal device of the present invention is preferably in the range of 5 to 80% by weight.

When the compound represented by the general formula (VI) is used in the liquid crystal material used in the liquid crystal device of the present invention, the total content of the compound in the liquid crystal material is 40% by weight.
The following is preferable, and 30% by weight or less is particularly preferable.

The ratio of the liquid crystal material in the light control layer is 70.
The range of 90 wt% is preferred.

The nematic liquid crystal material according to the present invention is
In addition to the compounds shown above, other properties of the liquid crystal material, namely,
For the purpose of improving the phase transition temperature, melting point, viscosity, Δn of the isotropic liquid and the liquid crystal, the solubility of the polymerizable composition and the like, and the modification of the interface of the transparent solid substance, etc. What is recognized as a liquid crystal material may be mixed.

The substrate used in the present invention may be a rigid material such as glass, or a flexible material such as a plastic film.
Appropriate transparent and opaque electrodes may be disposed on the entire surface or a part of the substrate, depending on the purpose. 2
Spacers may be interposed between the substrates in the same manner as in known liquid crystal devices. When the liquid crystal device of the present invention is used for a display device of a computer terminal, a display device of a projection or the like, it is preferable to provide a nonlinear element or an active element in the transparent electrode layer.

The liquid crystal material used in the liquid crystal device of the present invention can be used in a device in which liquid crystal droplets in which a liquid crystal material is microencapsulated are dispersed in a transparent solid substance between two substrates having a transparent electrode layer. Expected to be useful. The transparent solid substance formed between the substrates may be a fibrous or particle-like dispersed substance or a film in which a liquid crystal material is dispersed in a droplet form, but a substance having a three-dimensional network structure is preferable. More preferable. Further, it is preferable that the liquid crystal material forms a continuous layer, but it is important in forming a disordered state of the liquid crystal material to form an optical boundary surface and manifest light scattering.

If the average diameter of the shape of the three-dimensional network structure formed from such a transparent solid substance is too large or too small as compared with the wavelength of light, the light scattering property tends to deteriorate. The range of 0.2 to 2 μm is preferable. Also,
The thickness of the light control layer is preferably 2 to 30 μm, and particularly preferably 5 to 20 μm, depending on the purpose of use.

As these transparent solid components, glass particles and synthetic resins are suitable. For dispersing liquid crystal material in the form of small droplets or giving a three-dimensional network structure,
It is preferably a cured product of a thermosetting polymerizable composition or an actinic ray curable polymerizable composition containing a polymerizable compound. Further, a synthetic resin soluble in an organic solvent and a synthetic resin soluble in water are also suitable.

The polymerizable composition containing the polymerizable compound is
It is composed of a polymer-forming monomer and / or oligomer, a polymerization initiator and the like.

Examples of the polymer-forming monomer forming the transparent solid substance include styrene, chlorostyrene,
α-methylstyrene, divinylbenzene: As a substituent, methyl, ethyl, propyl, butyl, amyl, 2-
Ethylhexyl, octyl, nonyl, dodecyl, hexadecyl, octadecyl, cyclohexyl, benzyl, methoxyethyl, butoxyethyl, phenoxyethyl, allyl, methallyl, glycidyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-chloro-2-hydroxypropyl, Acrylate, methacrylate or fumarate having a group such as dimethylaminoethyl, diethylaminoethyl, etc .; ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-butylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, tri Mono (meth) acrylates such as methylolpropane, glycerin and pentaerythritol, or poly (meth) a Relate; vinyl acetate, vinyl butyrate or vinyl benzoate, acrylonitrile, cetyl vinyl ether, limonene, cyclohexene, diallyl phthalate, diallyl isophthalate, 2-, 3- or 4-
Vinyl pyridine, acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-hydroxymethyl acrylamide or N-hydroxyethyl methacrylamide and their alkyl ether compounds; 2 mol or more of ethylene oxide or propylene oxide is added to 1 mol of neopentyl glycol. Di (meth) acrylate of diol obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of trimethylolpropane; di or tri (meth) acrylate of triol; 2 mol or more per 1 mol of bisphenol A Di (meth) acrylate of diol obtained by adding ethylene oxide or propylene oxide of 2;
-A reaction product of 1 mol of hydroxyethyl (meth) acrylate and 1 mol of phenyl isocyanate or n-butyl isocyanate; poly (meth) acrylate of dipentaerythritol and the like can be mentioned, but trimethylolpropane triacrylate, tricyclo Decanedimethylol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, hexanediol diacrylate, neopentyl glycol diacrylate, tris- (acryloxyethyl) isocyanurate are particularly preferred.

Examples of the polymer-forming oligomer that forms the transparent solid substance include, for example, caprolactone-modified hydroxypivalic acid ester neopentyl glycol diacrylate (“HX-620”, “HX-2” manufactured by Nippon Kayaku Co., Ltd.).
20 ").

Examples of the polymerization initiator include 2-hydroxy-2-methyl-1-phenylpropan-1-one (“Darocur 1173” manufactured by Merck), 1-hydroxycyclohexyl phenyl ketone (“Ciba Geigy”). Irgacure 184 "), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1-
On (Merck "Darocur 1116"), benzyl dimethyl ketal (Ciba Geigy "Irgacure 651"), 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1 (Ciba)・ Geigy's "Irgacure 907"), 2,4-diethylthioxanthone (Nippon Kayaku's "Kayacure DET"
X ”) and ethyl p-dimethylaminobenzoate (“ Kayacure EPA ”manufactured by Nippon Kayaku Co., Ltd.), isopropylthioxanthone (“ Cantacure ITX ”manufactured by Ward Prekinsop) and ethyl p-dimethylaminobenzoate. Examples thereof include a mixture and the like, and liquid 2-hydroxy-2-methyl-1-phenylpropan-1-one is particularly preferable in terms of compatibility with the liquid crystal material and the polymer-forming monomer or oligomer.

In the liquid crystal device of the present invention, for example, a uniform solution containing a liquid crystal material, a polymer-forming monomer or oligomer, and a polymerization initiator is sandwiched between two substrates having electrode layers, or one of them is sandwiched. It may be coated on a substrate by using a coater such as a spin coater, and then the other substrate may be superposed, and it can be produced by irradiating this with ultraviolet rays to cure it, or by thermally polymerizing and curing it. .

Regarding the liquid crystal device manufactured in this manner, the inventors of the present invention diligently studied the liquid crystal material and the transparent solid substance that constitute the liquid crystal device utilizing the light scattering opaque state and the transparent state, and have high compatibility. This is due to the fact that the relationship has been found, and thereby more uniform display characteristics are exhibited.

[0046]

EXAMPLES The present invention will be described more specifically below by showing examples of the present invention. However, the invention is not limited to these examples.

In the following Examples and Comparative Examples, "%" means "% by weight". Moreover, each of the evaluation characteristics in each of the examples and comparative examples means the following symbols and contents.

(1) V ₉₀ , V ₁₀ : transmittance when the light transmittance (T ₀ ) of the device when no voltage is applied is 0% and the light transmittance does not change as the applied voltage increases. When (T ₁₀₀ ) is 100%, the applied voltage (V) at which the light transmittance is 90% is V ₉₀ , and the applied voltage at which the light transmittance is 10% is V ₁₀ .

(2) Contrast: With the device removed from the photometric state, the light transmittance when the light source is on is 100%, the light transmittance when the light is off is 0%, and the light of the device when no voltage is applied. When the transmittance is T ₀ and the light transmittance saturated with an increase in the applied voltage is T ₁₀₀ , it is a value expressed by T ₁₀₀ / T ₀ .

(3) T _MLC : a mixture of a liquid crystal material and a polymer-forming compound at a temperature required to form a uniform solution, and a temperature at which the isotropic liquid transitions to a nematic phase or undergoes phase separation upon cooling. To do.

The T _NI described as the physical property of each liquid crystal material is the nematic phase-isotropic liquid phase transition temperature, Δε
Means dielectric anisotropy, Δn means birefringence, and V _th
Shows the threshold voltage measured by the 8 μm TN type liquid crystal device.

Example 1 As a polymer-forming oligomer, "HX-220" (caprolactone-modified hydroxypivalic acid ester neopentyl glycol diacrylate manufactured by Nippon Kayaku Co., Ltd.) 19.8%, and as a polymerization initiator 2%
-Hydroxy-2-methyl-1-phenylpropane-1
A dimmer layer forming material of a uniform solution was prepared by mixing 0.2% of ON and 80% of the following liquid crystal composition (No. 3-1) as a liquid crystal material. Physical properties of this liquid crystal material and T of uniform solution
_MLC was as follows.

Composition of liquid crystal composition (No. 3-1):

[0054]

[Chemical 8]

Physical Properties Related to Liquid Crystal Composition (No. 3-1): Transition Temperature T _NI = 84.1 ° C. Refractive Index Δn = 0.229 Dielectric Anisotropy Δε = 16.0 Threshold Voltage V _th = 1.35V Transition temperature of homogeneous solution T _MLC = 29.9 ° C

This homogeneous solution was placed in an empty cell of 300 × 150 mm in size, which was prepared by using two ITO electrode glass substrates with a spacer having an average particle size of 10 μm interposed, and was 8 ° C. higher than the transition temperature T _MLC of the homogeneous solution. Vacuum injection was performed under temperature.
While maintaining this at a temperature 3 ° C. higher than the transition temperature T _MLC of the homogeneous solution, a metal halide lamp (80 W / cm ² )
Under the speed of 3.5m / min, 500mJ / cm ²
The polymer-forming oligomer was cured by irradiating it with ultraviolet light having an energy equivalent to that to obtain a liquid crystal device of the present invention.
The cross section of the cured product formed between the substrates of the obtained liquid crystal device was observed with a scanning electron microscope, and a transparent solid substance having a three-dimensional network structure made of a polymer was observed. The obtained liquid crystal device showed uniform display characteristics without unevenness, and the values were as follows.

V ₁₀ : 6.8V V ₉₀ : 23.3V T ₀ : 2.1% T ₁₀₀ : 82.6% Contrast: 1:39

(Comparative Example 1) In Example 1, instead of the liquid crystal composition (No. 3-1), the following mixed liquid crystal (3-a) was used.
A comparative liquid crystal device was obtained in the same manner as in Example 1 except that was used.

Composition of mixed liquid crystal (No. 3-a):

[0060]

[Chemical 9]

Physical Properties of Mixed Liquid Crystal (No. 3-a): Transition Temperature T _NI = 99.3 ° C. Refractive Index Δn = 0.238 Dielectric Anisotropy Δε = 13.7 Threshold Voltage V _th = 1 0.68V Transition temperature of homogeneous solution T _MLC = 58.3 ° C

The difference between the two is that the fluorotolan structure in the liquid crystal material is slightly different. The cross section of the cured product formed between the substrates of the obtained liquid crystal device was observed with a scanning electron microscope, and a transparent solid substance having a three-dimensional network structure made of a polymer was observed. However, although the production was tried several times, there were some in which streaky or irregular irregularities were observed. The display characteristics of the obtained liquid crystal device were as follows as a result of performing measurement by selecting a more uniform spot.

Characteristics of the obtained liquid crystal device: V ₁₀ : 8.0V V ₉₀ : 27.3V T ₀ : 4.0% T ₁₀₀ : 82.1% Contrast: 1:21

The defect in the liquid crystal device of Comparative Example 1 is that the liquid crystal material and the polymer-forming compound are separated by controlling the holding temperature when vacuum-injecting the uniform solution, the holding temperature when irradiating with ultraviolet rays, and the like. This is considered to be due to the compatibility and the transition temperature T _{M LC} of the uniform solution reflecting this. Of course, it is possible to fabricate the liquid crystal device at a higher temperature, but in this case, the formed three-dimensional network structure becomes finer and the intended display characteristics are restricted.

Liquid crystal device obtained in Example 1 and Comparative Example 1
From the comparison of the liquid crystal device obtained in
Compatibility with water-soluble compounds, that is, transition temperature of homogeneous solution
Degree T _MLCBy using a light control layer forming material having a lower
Streaky or irregular irregularities in the liquid crystal device of Comparative Example 1
Understand that the problem that occurs occurs can be solved.

Comparative Example 2 The following mixed liquid crystal (3-b) was used instead of the liquid crystal composition (No. 3-1) in Example 1.
A comparative liquid crystal device was obtained in the same manner as in Example 1 except that was used.

Composition of mixed liquid crystal (No. 3-b):

[0068]

[Chemical 10]

Physical Properties of Mixed Liquid Crystal (No. 3-b): Transition Temperature T _NI = 69.8 ° C. Refractive Index Δn = 0.234 Dielectric Anisotropy Δε = 15.1 Threshold Voltage V _th = 1 .40V transition temperature of homogeneous solution T _MLC = 29.5 ° C

With respect to the obtained liquid crystal device, the cross section of the cured product formed between the substrates was observed using a scanning electron microscope. As a result, a transparent solid substance having a three-dimensional network structure made of a polymer was observed. However, although the production was tried several times, as in Comparative Example 1, there were some in which streaky or irregular irregularities were observed. The display characteristics of the obtained liquid crystal device were as follows as a result of performing measurement by selecting a more uniform spot.

Characteristics of the obtained liquid crystal device: V ₁₀ : 12.5V V ₉₀ : 35.0V T ₀ : 4.9% T ₁₀₀ : 79.1% Contrast: 1:16

In the liquid crystal composition used in Example 1, the temperature difference between the transition temperature T _NI of the liquid crystal composition and the transition temperature T _MLC of the uniform solution was as large as about 50 ° C., on the other hand, Comparative Examples 1 and 2
Since the temperature difference between them is as small as about 40 ° C., the liquid crystal material used in the present invention exhibits higher compatibility with the polymer-forming compound, and a dimming layer-forming material having a lower transition temperature T _MLC can be obtained. It can be understood that the liquid crystal device can be provided, and as a result, it is possible to provide a liquid crystal device having uniform display characteristics by reducing the occurrence of streaky or irregular irregularity without deteriorating the transparent-opaque contrast and driving voltage.

(Example 2) In place of the liquid crystal composition (No. 3-1) in Example 1, the following liquid crystal composition (No.
A liquid crystal device of the present invention was obtained in the same manner as in Example 1 except that 3-2) was used.

Composition of liquid crystal composition (No. 3-2):

[0075]

[Chemical 11]

Physical Properties Related to Liquid Crystal Composition (No. 3-2): Transition Temperature T _NI = 82.5 ° C. Refractive Index Δn = 0.234 Dielectric Anisotropy Δε = 14.3 Threshold Voltage V _th = 1.60V transition temperature of homogeneous solution T _MLC = 32.1 ° C

With respect to the obtained liquid crystal device, the cross section of the cured product formed between the substrates was observed by using a scanning electron microscope. As a result, a transparent solid substance having a three-dimensional network structure made of a polymer was observed. The obtained liquid crystal device showed uniform display characteristics without unevenness, and the values were as follows.

Characteristics of the obtained liquid crystal device: V ₁₀ : 8.6V V ₉₀ : 19.1V T ₀ : 2.6% T ₁₀₀ : 80.0% Contrast: 1:31

Example 3 In place of the liquid crystal composition (No. 3-1) in Example 1, the following liquid crystal composition (No.
A liquid crystal device of the present invention was obtained in the same manner as in Example 1 except that 3-3) was used.

Composition of liquid crystal composition (No. 3-3):

[0081]

[Chemical 12]

Physical Properties Related to Liquid Crystal Composition (No. 3-3): Transition Temperature T _NI = 84.2 ° C. Refractive Index Δn = 0.255 Dielectric Anisotropy Δε = 13.2 Threshold Voltage V _th = 1.79V Transition temperature of homogeneous solution T _MLC = 34.6 ° C

With respect to the obtained liquid crystal device, the cross section of the cured product formed between the substrates was observed using a scanning electron microscope. As a result, a transparent solid substance having a three-dimensional network structure made of a polymer was observed. The obtained liquid crystal device showed uniform display characteristics without unevenness, and the values were as follows.

Characteristics of the obtained liquid crystal device: V ₁₀ : 9.6V V ₉₀ : 22.3V T ₀ : 1.2% T ₁₀₀ : 79.9% Contrast: 1:67

Example 4 In place of the liquid crystal composition (No. 3-1) in Example 1, the following liquid crystal composition (No.
A liquid crystal device of the present invention was obtained in the same manner as in Example 1 except that 3-4) was used.

Composition of liquid crystal composition (No. 3-4):

[0087]

[Chemical 13]

Physical Properties Related to Liquid Crystal Composition (No. 3-4): Transition Temperature T _NI = 87.3 ° C. Refractive Index Δn = 0.224 Dielectric Anisotropy Δε = 13.6 Threshold Voltage V _th = 1.59V Transition temperature of homogeneous solution T _MLC = 37.8 ° C

The cross section of the cured product formed between the substrates of the obtained liquid crystal device was observed with a scanning electron microscope. As a result, a transparent solid substance having a three-dimensional network structure made of a polymer was observed. The obtained liquid crystal device showed uniform display characteristics without unevenness, and the values were as follows.

Characteristics of the obtained liquid crystal device: V ₁₀ : 6.8V V ₉₀ : 14.4V T ₀ : 1.9% T ₁₀₀ : 81.9% Contrast: 1:43

Example 5 The following liquid crystal composition (No. 3-1) was used instead of the liquid crystal composition (No. 3-1) in Example 1.
A liquid crystal device of the present invention was obtained in the same manner as in Example 1 except that 3-5) was used.

Composition of liquid crystal composition (No. 3-5):

[0093]

[Chemical 14]

Physical Properties Related to Liquid Crystal Composition (No. 3-5): Transition Temperature T _NI = 81.6 ° C. Refractive Index Δn = 0.217 Dielectric Anisotropy Δε = 19.4 Threshold Voltage V _th = 1.41V Transition temperature of homogeneous solution T _MLC = 32.9 ° C

With respect to the obtained liquid crystal device, the cross section of the cured product formed between the substrates was observed using a scanning electron microscope. As a result, a transparent solid substance having a three-dimensional network structure made of a polymer was observed. The obtained liquid crystal device showed uniform display characteristics without unevenness, and the values were as follows.

Characteristics of the obtained liquid crystal device: V ₁₀ : 6.8V V ₉₀ : 14.4V T ₀ : 2.6% T ₁₀₀ : 80.9% Contrast: 1:31

[0097]

Industrial Applicability The liquid crystal device of the present invention is a light-scattering liquid crystal device which does not require a polarizing plate and has a bright image quality, and has a higher compatibility between the liquid crystal material and the polymer-forming compound, that is, the transition temperature of a uniform solution. By having a light control layer forming material having a lower T _MLC, it is possible to reduce the occurrence of streaky or irregular irregularity without deteriorating the contrast between transparent and opaque and driving voltage, and to provide uniform display characteristics. There is something. Therefore, the liquid crystal device of the present invention, even a liquid crystal material exhibiting a liquid crystal phase at a relatively high temperature, a liquid crystal device exhibiting more uniform light scattering characteristics, or a relatively large liquid crystal device can be more easily produced by the vacuum injection method, For example, it is also useful for a decorative display device such as an advertising board or a display device of a computer terminal.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-6-279332 (JP, A) JP-A-4-296387 (JP, A) JP-A-5-341272 (JP, A) JP-A-4-341 128258 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09K 19/02-19/46

Claims (9)

(57) [Claims] 1. A liquid crystal device in which at least one having a transparent electrode layer has a light control layer sandwiched between two transparent substrates, and the light control layer contains a liquid crystal material and a transparent solid substance. The liquid crystal material is (a) a general formula (I) and a general formula (II) (In the formula, R ¹ and R ² are each independently (i) 2 carbon atoms.
To a linear alkyl group having 5 to 5 carbon atoms, (ii) an alkenyl group having 2 to 5 carbon atoms, or (iii) an alkyl group having 1 to 5 carbon atoms in which a hydrogen atom is an alkoxyl group having 1 to 5 carbon atoms. It represents a substituted alkoxyalkyl group, and X ^{1 to} X ⁴ each independently represent H or F. ) A compound selected from the first group of compounds and (b) the general formula (III) to
General formula (V): (In the formula, R ³ is (i) a linear alkyl group having 2 to 5 carbon atoms, (ii) an alkenyl group having 2 to 5 carbon atoms, or (ii
i) represents an alkoxyalkyl group in which a hydrogen atom of an alkyl group having 1 to 5 carbon atoms is substituted with an alkoxyl group having 1 to 5 carbon atoms, and R ⁴ is a linear alkyl group having 2 to 8 carbon atoms. Or an alkoxy group, R ⁵ represents a linear alkyl group having 2 to 8 carbon atoms, and k and m each independently represent 0 or 1. ) A liquid crystal device containing a compound selected from the second compound group represented by: 2. The liquid crystal device according to claim 1, wherein the liquid crystal material contains the compound represented by the general formula (I) according to claim 1 and the compound represented by the general formula (IV). 3. The liquid crystal device according to claim 2, further comprising the compound represented by the general formula (V) according to claim 1. 4. The liquid crystal material further has the general formula (VI): (In the formula, R ⁶ represents a linear alkyl group having 2 to 7 carbon atoms, and R ⁷ represents a linear alkyl group having 1 to 7 carbon atoms or a linear alkyl group having 1 to 7 carbon atoms. Represents an alkoxy group of, n represents an integer of 0 or 1, Y ¹ represents a single bond,
COO- or represents -CH ₂ CH ₂ -, X ⁵ is F or C
Represents H ₃ . 3. A liquid crystal device according to claim 1, further comprising a compound selected from the third compound group represented by). 5. The liquid crystal device according to claim 4, wherein the liquid crystal material contains the compound represented by the general formula (I) according to claim 1 and the compound represented by the general formula (IV). 6. A liquid crystal device according to claim 5, further comprising a compound represented by the general formula (V) according to claim 1. 7. The liquid crystal device according to claim 4, wherein the liquid crystal material contains the compound represented by the general formula (II) according to claim 1 and the compound represented by the general formula (IV). 8. The light control layer according to claim 1, wherein the liquid crystal material forms a continuous layer, and the transparent solid substance forms a three-dimensional network structure in the continuous layer. 4,
5. A liquid crystal device according to 5, 6 or 7. 9. The liquid crystal material contains a compound selected from the first compound group in a total amount of 5 to 80% by weight, and a compound selected from the second compound group in a total amount of 5 to 80% by weight. 8
0% by weight, 1, 2,
The liquid crystal device according to 3, 4, 5, 6, 7 or 8.