JPH0255318A - Device for using liquid crystal - Google Patents

Abstract

PURPOSE:To allow the easy and inexpensive increase of an area by using a liquid crystal dispersed film formed by dispersing a liquid crystal into a matrix consisting of a polymethacrylate resin as a liquid crystal layer. CONSTITUTION:The liquid crystal formed by dispersing the liquid crystal into the matrix consisting of the polymethacrylate is used as the liquid crystal layer. The ratio at which the liquid crystal occupies in the liquid crystal dispersed film is preferably in a 30-90wt.% range. Two sheets of substrates for holding the liquid crystal are required in case of using the ordinary liquid crystal and further a spacer for holding the two substrates at a specified spacing is needed. In addition, an error is liable to arise in the thickness. These problems are solved if the above-mentioned film is used. The device is, therefore, adequately usable for a large-area display device and light control filter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid crystal device used as a liquid crystal display device, a light amount adjustment film, and the like.

[Prior Art and Problems to be Solved by the Invention] Devices using liquid crystals are used not only as information display devices but also as filters that freely adjust the amount of light.

These devices hold fluid liquid crystals within an extremely narrow gap of several to several dozen units and have a uniform thickness.
A high degree of gap accuracy is required because it is driven by applying a voltage or the like. Therefore, spacers and gap adjustment materials with uniform thickness.

Furthermore, a hard substrate such as glass is required.

However, in order to manufacture a large-area device using liquid crystal using this method, it is necessary to form a gap with a uniform thickness over a large area, which is not easy to achieve. This is especially difficult in cases such as liquid crystal display devices, where it is not only necessary to simply change the orientation of the liquid crystal, but also to accurately display the desired object after changing the orientation of the liquid crystal. uses an LCD!
This is one of the reasons that hinders the widespread application of A-stations.

In order to solve these drawbacks, a method has been proposed in which a liquid crystal encapsulated in a capsule is used in a capsule medium (Japanese Patent Application Laid-Open No. 62-4EL789), but due to variations in the diameter of the capsule, However, the optical characteristics are affected and the driving voltage is increased.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a liquid crystal device that can be easily, inexpensively, and highly reliable and made to have a large area by improving the drawbacks in configuring a device using a large area liquid crystal. With the goal.

[Means and effects for solving the problems] In order to achieve the above object, the device using liquid crystal of the present invention uses a liquid crystal dispersion film in which liquid crystal is dispersed in a matrix made of polymethacrylic acid ester resin as a liquid crystal layer. This is what I did.

In the device using a liquid crystal of the present invention, a film in which liquid crystal is dispersed in a polymethacrylate resin in an insoluble state in the resin is used in place of the conventional liquid crystal layer.

Therefore, when using a conventional liquid crystal layer, two substrates are required to hold it, and a spacer is also required to hold the two substrates at a certain distance. Because the thickness tends to vary,
In particular, there is a problem that it is difficult to obtain a display device with a large area, but according to the present invention, a device using liquid crystal can be obtained in which these problems are solved. Therefore, the device using liquid crystal of the present invention.

It can be suitably used for large-area display devices and dimming filters. Furthermore, in the present invention, by using a polymethacrylate ester resin as a matrix material, it is possible to obtain a device using a liquid crystal, which has high contrast when an electric field is turned on and off, and has excellent display functions, dimming functions, etc. .

The present invention will be explained in more detail below.

As described above, the liquid crystal device of the present invention uses a liquid crystal dispersion film in which liquid crystals are dispersed in a matrix made of polymethacrylate resin as a liquid crystal layer of a liquid crystal device such as a liquid crystal display device or a light amount adjustment filter. This is what was used.

Here, the polymethacrylate resin constituting the matrix is represented by the following formula (1) (where R represents an alkyl group, a cyclohexyl group, a hydroxy group, a glycidyl group, a benzyl group, or an allyl group). It is a resin whose main component is a polymer of llimer. In this case, the amount of the above monomer units is 60% of the total
% (weight %, same hereinafter) or more. In addition, in formula (1), as the alkyl method, the number of carbon atoms is 1 to
18, especially 1 to 8 are preferred.

Specific examples of the above polymethacrylate resin include polymethyl methacrylate, polyethyl methacrylate,
Examples include poly n-butyl methacrylate, poly i-butyl methacrylate, monobutyl poly methacrylate, poly stearyl methacrylate, poly cyclohexyl methacrylate, poly hydroxyethyl methacrylate, poly glycidyl methacrylate, and the like. These may be used alone or in combination of two or more.

Since the matrix made of these polymethacrylic acid ester resins is used as a matrix of an optical film, it preferably has a light transmittance of 50% or more, more preferably 80% or more.

Further, the refractive index of the matrix is preferably close to the refractive index of the liquid crystal dispersed therein, and it is recommended that the difference therebetween be 0.5 or less, preferably 0.3 or less.

Further, the matrix may contain a heat stabilizer, a light stabilizer, an antioxidant, a lubricant, a surfactant, a trace amount of an inorganic filler, etc., as necessary.

The liquid crystal dispersed in the liquid crystal dispersion film is not particularly limited, and when mixed with the polymethacrylate resin, the resin phase and the liquid crystal phase exist as different phases, and these phases are mixed with each other, Any liquid crystal that can exist in the resin layer in the form of continuous domains, has such properties, and can be used as a liquid crystal for devices using liquid crystals can be used.

Specific examples of the liquid crystal include 4-methoxybenzylidene-4'-butylaniline (MBBA) and 4-ethoxybenzylidene-4'-butylaniline (EB, BA).
Chemical formula represented by: (where n and m are positive integers,
The same applies hereinafter); alkoxybenzylidenealkylaniline liquid crystal compound; 4-butylbenzylidene-4'
- Chemical formula represented by cyanoaniline etc.: Azoxy liquid crystal compound; 4-pentyl-4'
-Alkylbenzylidene cyanoaniline liquid crystal compound represented by the chemical formula represented by -methoxyazobenzene, etc.Alkoxybenzylidene cyanoaniline liquid crystal compound represented by the chemical formula represented by 4-pentyloxybenzylidene-4'-cyanoaniline etc. Compound; Azo liquid crystal compound represented by the chemical formula represented by 4-butyl-4'-methoxyazoxybenzene, 4-hexyl-4'-butoxyazoxybenzene, etc.; 4-octyloxy-41-pentyl Oxyphenylbenzoate.

4-pentyl-4'-methoxyphenylbenzoate,
4-heptyl 4'-cyanophenylbenzoate, 4
- Phenylbenzoate liquid crystal compounds represented by cyanobenzene-4'-butylphenylbenzoate, 4-pentylbenzene-4'-butylphenylbenzoate, etc.; 4-cyano-4'-pentylbiphenyl, 4-cyano-4'- hebutyloxybiphenyl, 4-cyano-
4”-n-propyl-p-terphenyl, 4-cyano-
Biphenyl liquid crystal compounds represented by 4'-octylbiphenyl, 4-cyano-4'-octyloxybiphenyl, etc.; 4-hexyl-42-butylcyclohexylcarboxybenzoate, 4-pentyloxy-4'-
Pentyl cyclohexyl carboxybenzoate, 4-
Cyano-4'propylcyclohexyl lupoxybenzoate.

Cyclohexylcarboxylic acid ester liquid crystal compound represented by 4-cyanobenzene-4'-ethylcyclohexylcarboxybenzoate; 4-propyl 1-
(4-noncyanophenyl)cyclohexane, 4-pentyl-1-(4'-cyanobiphenyl)cyclohexane, 4-propyl-1-(4'-ethoxyphenyl)cyclohexane.

Phenylcyclohexane-based and biphenylcyclohexane-based liquid crystal compounds represented by 4-pentyl-1-(4'-ethylphenyl)cyclohexane;4-pentyl-1-(4'-cyanophenyl)-pyridine, 4-
Phenylpyridine liquid crystal compounds such as cyano-1-(4'-pentoxyphenyl)pyridine; phenyldioxane liquid crystal compounds such as 4-butyl-1-(4'-cyanophenyl)dioxane; Cyclohexylcyclohexane-based and cyclohexylcyclohexane ester-based liquid crystal compounds represented by 4-ethyl-1-(4'-cyanocyclohexyl)cyclohexane, 4-propyl-4'-propylcyclohexyl-cyclohexanoate; 4-propylcyclohexyl -4'-
Examples include cyclohexylethane liquid crystal compounds represented by ethoxyphenylethane, 4-pentylcyclohexyl-4'-cyanophenylethane, and the like.

These may be used alone or in combination of two or more.

As mentioned above, the liquid crystal layer of the present invention is made by dispersing liquid crystal in the polymethacrylate resin matrix in a state different from that of the matrix in an undissolved state, and therefore, due to the dispersion of the liquid crystal, the matrix is It is formed to have a spongy structure, so to speak.
Here, the dispersion mode of liquid crystal or the above-mentioned sponge-like structure refers to a state in which the polymethacrylate resin component forms a network to form a continuous phase, while the voids (pores and independent voids) are filled with liquid crystal. It refers to the state that exists in In this case, all of the voids are connected from the front to the back of the matrix, or are connected to one of the front and back sides, so that the liquid crystal is continuous from the front to the back of the matrix, or to one of the front and back sides. Although it is preferable that the liquid crystals are partially independent island-like ones (capsule-like ones), in this case, the liquid crystals are locally continuous with each other in the matrix. However, the rate at which this liquid crystal forms a continuous layer is such that preferably 40% or more, more preferably 50% or more of the volume of the liquid crystal is continuous to at least one of the front and back sides of the matrix. It is preferable.

There is no limit to the size of the voids created in the film-like matrix material by dispersing the liquid crystal (i.e., the liquid crystals), but if the length of the short axis of the voids is defined as the average diameter. From the viewpoint of uniformity of display quality, it is preferable that the average diameter is 150 or less, particularly 100 or less.

Usually, the proportion of liquid crystal in the polymethacrylate resin/liquid crystal film is 30 to 90%, preferably 40 to 80%. The above percentage is 30%
If it is less than that, most of the liquid crystal may dissolve in the matrix material, or even if it is dispersed as a liquid crystal phase, it may exist as independently dispersed particles. on the other hand,
If it exceeds 90%, it may become difficult to form a liquid crystal dispersion film.

The thickness of the liquid crystal dispersion film is usually 2 to 1000p, preferably 5 to 1100p. The thickness is 100
When it exceeds 0-, the driving voltage becomes high and the material cost increases, and when it is less than 2-, the influence of thickness variations tends to become large.

Such films are prepared by adding solvents and various additives to adjust the viscosity and handleability of this composition as necessary to a composition consisting of a polymethacrylate resin and liquid crystal. It can be formed by methods such as a casting method, a water surface spreading method, a doctor blade method, a roll coating method, a dipping method, a spray method, and an electrostatic coating method.

For example, in the case of a casting method, a solution or dispersion of polymethacrylate resin is prepared using a solvent, and the liquid crystal is dispersed or dissolved in this solution or dispersion and then the film is formed. It is formed. In this case, the solvent for dissolving the polymethacrylic acid ester resin preferably has a high solubility, but it may be selected appropriately depending on the type of the liquid crystal.

In addition, when using the water surface spreading method, a liquid crystal dispersed film having a desired thickness can be formed by spreading a solution containing a polymethacrylate resin and liquid crystal on a non-solvent surface.

Examples of additives added to the composition consisting of polymethacrylate resin and liquid crystal include dichroic dyes such as azo, methine, merocyanine, and anthraquinone dyes that are added to enable color display. Dopant liquid crystals added to widen the temperature range, lower drive voltage, and reduce viscosity; Life-enhancing agents to improve the lifespan of liquid crystal display elements.

The liquid crystal dispersion film may be produced as a single film, but the thickness of the film is preferably 5 to 200%
Because it is thin (4111), it may be difficult to handle. In such a case, it may be formed directly on an electrode of a protective substrate having a thin film electrode or on an alignment film when manufacturing a device using a liquid crystal.

In this case, in order to control the initial alignment state of liquid crystal molecules in the liquid crystal dispersion film, a polymer film such as polyimide resin 5 polyvinyl alcohol is formed on the surface of a substrate such as glass or polymer film to which electrodes have been attached in advance. coating with lecithin, hexadecylamine, myristic acid complexes, chromium complexes, silane coupling agents, etc., surface treatment by oblique evaporation of various oxides, fluorides, metals, ion shower, photo etching, and replicas. It is also possible to apply a grating according to the method. Furthermore, depending on the case, the above-mentioned means and mechanical alignment treatment by rubbing may be used in combination.

When the liquid crystal dispersion film formed in this way is used as a liquid crystal layer of a device using liquid crystal, the adhesion area between the alignment film and the liquid crystal is larger than that of a polymer film in which liquid crystal is dispersed in island form. Can be driven with low voltage. Furthermore, since the liquid crystal dispersion film used in the present invention has a constant thickness, it can be used as a display layer or the like having a uniform thickness over a wide area without using a spacer.

Next, a liquid crystal device of the present invention using the liquid crystal dispersion film will be explained.

Devices using liquid crystals include DS system and TN system.

Any of the usual methods such as GH method, PC method, and ECB method may be used.

In addition, depending on the above method, it may be used in combination with polarizing plates, light reflection/diffusion plates, etc. in the same way as conventional liquid crystal devices. Various filters such as filters can be used together depending on the purpose.

There is no particular restriction on the connection method between the liquid crystal device of the present invention and the waste electronic circuit, and any conventional connection method such as a bin connector, an elastic connector, or a flexible connector may be used.

When used as a transmissive liquid crystal element, an incandescent light bulb, a white halogen light bulb, a fluorescent lamp, an electroluminescent lamp, a light emitting diode, a plasma light emitting panel, etc. can be used as a backlighting light source.

A general liquid crystal device consists of, for example, a transparent conductive film and a transparent substrate provided on one side of a liquid crystal layer, and a transparent conductive film and transparent substrate provided on the other side, or a thin film electrode and a substrate. An alignment film and/or an insulating film may be formed between the thin film electrode and the liquid crystal layer, and a polarizing plate or the like may be further attached.

The alignment film may be a commonly used plastic film made of polyester, polyamide, polyimide amide, polyvinyl alcohol, etc., rubbed by a conventional method, or a film made by diagonally depositing silica on a transparent screen plate may also be used.

This alignment film has a great effect on the performance of devices using liquid crystals, and it is important to decide whether to provide it on both sides or one side of the liquid crystal dispersion film, whether to use the same or different materials for the front and back alignment films, and the direction of rubbing. It is preferable to select the appropriate method depending on the material of the alignment film, the liquid crystal used, the matrix material, the balance of these alignment materials, etc.
Although it cannot be said generally, - In the case of nematic alignment for boat fishing, it is advantageous to provide the liquid crystal dispersion film so that the alignment direction is the same on both sides, and in the case of smectic alignment, it is advantageous to provide the liquid crystal dispersion film with the same alignment direction. By changing the material of the alignment films on both sides of the film,
It tends to be better to rub on one side, but it is not limited to this.

〔Effect of the invention〕

As explained above, the device using liquid crystal of the present invention uses a specific liquid crystal dispersion film as a liquid crystal layer, so that
It is possible to easily form and maintain an inter-electrode gap with a uniform thickness, and it has extremely high contrast when the electric field is turned on and off, and has good display and dimming functions. As a result, even when glass is used as the surface material, it is possible to increase the surface area, and when a polymer film such as polyethylene phthalate is used as the surface material, it is possible to achieve a large surface area, yet lightweight.
In addition, it is possible to manufacture a device using a liquid crystal that can follow curved surfaces. Therefore, by using the liquid crystal device of the present invention, display devices, light control devices, etc. can be made even thinner;
It is possible to reduce the weight.

EXAMPLES The present invention will be specifically explained below with reference to Examples and Comparative Examples, but the present invention is not limited to the Examples below.

[Example, comparative example]

50 parts (weight %,
(same below), 4-hebutyl-41-cyanobiphenyl (
After applying a 20% 1,2-dichloroethane solution of 50 parts of a composition manufactured by BDH Co., Ltd. (trade name: -21), it was dried at room temperature for 2 hours to produce a liquid crystal dispersion film with a thickness of 50 mm.

On this laminate film, patterned ITO/
! The polyester sheet having a thickness of 125/lrn was crimped with nip rolls so that the ITO layer was on the liquid crystal dispersion film side, to produce a 300 am x 300 ann liquid crystal dispersion film sandwich sheet 1 (device using liquid crystal).

The obtained device was cloudy as it was due to light scattering by the liquid crystal, but when a voltage of 80 V/60 Hz was applied between the two electrodes, only the area between the patterned electrodes became transparent and a pattern was displayed.

Tsubaki - Eclipse A Polycyclohexyl methacrylate (Mitsubishi Rayon Co., Ltd. JID, trade name Acrybet (H)) was used instead of the polymethyl methacrylate of Example 1, and a cyanobiphenyl mixture was used instead of 4-hebutyl-4'-cyanobiphenyl. Liquid crystal (BDH)
When a liquid crystal dispersion film sandwich sheet was prepared and tested in the same manner using each of the following liquid crystal dispersion film sandwich sheets, the same results as in Example 1 were obtained.

Liquid crystal dispersion film sandwich sheets of Comparative Examples 1 to 3 were prepared in the same manner as in Example 1 using the combinations of polymers and liquid crystals shown in Table 1 below.

Next, the light transmittance of the liquid crystal dispersion film sandwich sheets of Examples 1 and 2 and Comparative Examples 1 to 3 was measured using the apparatus shown in FIG. 1 when an AC electric field of 80 V/60 Hz was applied. In the measuring device shown in Fig. 1, 1 is a sample (liquid crystal dispersion film sandwich sheet, 2 and 2 are transparent electrodes, and 3 is a light source (He-Ne laser beam, wavelength 63 mm).
2.8no+), 4 is a photodiode, 5 is a function generator, 6 is a preamplifier, and 7 is a transient memory, and the laser light transmittance in the electrolysis on/off state was investigated. The results are shown in Table 2 below.

Table 2 The light transmittance measurement test described above can quantitatively examine the contrast required to achieve the purpose of the device such as display function and dimming function when the liquid crystal device is actually driven. Generally, in order to achieve these functions, it is preferable that the difference in light transmittance between the electrolysis on and off states is large. From the results in Table 2, it can be seen that when polymethacrylate resin is used as the matrix material of the liquid crystal dispersion film, it is possible to obtain a liquid crystal device that has excellent contrast and exhibits good display function, dimming function, etc. is recognized.

500m+ width and 50m+ width with an ITO layer pre-formed on one side.
Example 1 was deposited on a float glass plate with a thickness of 3 m and a thickness of 0+ nm.
In the same manner as above, a liquid crystal dispersion film with a thickness of 30 tones was formed,
Furthermore, by laminating and fixing the same float glass plate as above on this film, a liquid crystal panel of the present invention (Example 3) was obtained.
was created.

On the other hand, the above pair of float glass plates are stacked on top of each other with a polyethylene terephthalate spacer having a width of 10 awn and a thickness of 30 μm sandwiched between them, and 4-hebutyl-42-cyanobiphenyl is injected into the spacer. In this way, a conventional liquid crystal panel (Comparative Example 4) was manufactured.

Next, the thickness of both panels is shown in FIG.

Each point B and C was examined. In this case, since the thickness of the glass plate and spacer varies, the total thickness of the glass plate and spacer at each measurement point and the thickness of the panel after lamination are combined are measured, and the following formula (2) % formula % (2) (However, tI is the thickness at measurement point i of the panel after lamination, t
Mu□ and tmu2 are the thickness of the glass at measurement point i, and t, respectively.
4 indicates the thickness of the spacer at measurement point i. ), find the difference (Δt') between the two, and use this value to determine each point A, B.
, C was evaluated for changes in thickness.

The results are shown in Table 3 below.

Table 3 As is clear from the results in Table 3, when a film in which liquid crystal is dispersed in a matrix made of polymethacrylic acid ester resin is used as liquid crystal M, the matrix supports the weight of the glass plate, and It is recognized that a liquid crystal panel having a uniform thickness as a whole can be obtained as shown in No. 3. On the other hand, in the case of Comparative Example 4 in which only the liquid crystal was sandwiched between large-area glass plates, the central portion of the glass was bent due to the weight of the glass, and the thickness of the liquid crystal layer was reduced at the central portion. Therefore, in Example 3, the thickness at the edges and the center is equal, and the transparency when voltage is applied is uniform over the entire area, whereas in Comparative Example 4, when voltage is applied, the center part becomes cloudy, and the transparency becomes uniform. The results were uneven.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a laser light transmittance measuring device used for measurements in Examples, and FIG. 2 is an explanatory diagram showing measurement points when measuring film thickness in Examples. Figure 1 Applicant Brideston Co., Ltd. Agent Patent Attorney Takashi Kojima Figure 2

Claims (1)

[Scope of Claims] 1. A device using liquid crystal, characterized in that the liquid crystal layer is a liquid crystal dispersion film in which liquid crystal is dispersed in a matrix made of polymethacrylate resin. 2. The proportion of liquid crystal in the liquid crystal dispersion film is 3.
2. The liquid crystal device according to claim 1, wherein the amount is 0 to 90% by weight.