JPH01252689A - Liquid crystal device - Google Patents

Abstract

PURPOSE:To enable driving at a low voltage and enlargement of the title device without the use of a polarizing plate, by disposing a particular light intensity modifier layer between a pair of substrates each having an electrode layer wherein at least one of the substrates is transparent. CONSTITUTION:A nematic liq. crystal material (a) contg. a compd. of the formula (wherein R is a 1-10C straight-chain alkyl), a component (b) which is pref. an ultraviolet-curable polymerizable monomer or oligomer and converted into a transparent solid substance upon polymn., and optionally additives (c), such as a polymn. initiator, a chain transfer agent, a photosensitizer or a dye crosslinking agent, are mixed together, thereby obtaining a soln. This soln. is disposed between a pair of substrates each having an electrode layer wherein at least one of the substrates is transparent. The soln. is irradiated with ultraviolet rays passed through the transparent substrate to conduct polymn. of component (b). Thus, a light intensity modifier layer is formed, in which component (a) forms a continuous phase and a three-dimensional network, transparent solid substance composed of a polymer of component (b) is dispersed in the continuous phase of component (a).

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a thin film containing a liquid crystal that can be formed over a large area. It can be electrically operated to block or transmit light, and is used as a screen to block the view in building windows and show windows, as well as curtains to control lighting. By electrically switching the display, it can be used as a display device for advertising boards, guide boards, decorative display boards, etc.

(Prior art) Liquid crystal display elements have conventionally used nematic liquid crystal.
type and STN type are in practical use.

Also, devices using ferroelectric liquid crystals have been proposed. These require a polarizing plate and also require alignment treatment. On the other hand, as a method for manufacturing large, inexpensive liquid crystal devices that are bright and have good contrast without requiring these devices, a method is known in which liquid crystal encapsulation is used to disperse liquid crystal droplets in a primer and form the polymer into a film. It is being Here, as the encapsulating substance, gelatin, gum arabic, polyvinyl alcohol, etc. have been proposed (% Table No. 58-501631, USP 443
No. 5047).

In the technology disclosed in the above specification, if the liquid crystal molecules encapsulated with polyvinyl alcohol have positive dielectric constant anisotropy in a thin layer, the liquid crystal molecules can be encapsulated in the presence of an electric field. are aligned in the direction of the electric field, resulting in a refractive state of the liquid crystal. When the refractive index n of the polymer and the refractive index n of the polymer are equal, transparency is exhibited. When the electric field is removed, the liquid crystal molecules return to their random alignment, and the refractive index of the liquid crystal droplet shifts by n.The liquid crystal droplet scatters light at its interface, blocking the transmission of light. becomes cloudy. In addition to the above-mentioned techniques, there are several other known techniques for making thin films of polymers that are highly dispersed and contain encapsulated liquid crystals.
No. 1-502128 discloses a liquid crystal dispersed in a resin, and JP-A-62-2231 discloses a liquid crystal dispersed in a special ultraviolet curing polymer.

(Problems to be Solved by the Invention) Important characteristics required for the practical use of large liquid crystal devices such as those described above are (1) ability to drive at low voltage (iii) sufficient contrast aii)
Time division driving may be possible.

In particular, (1) and (ir*) are extremely important characteristics in order to make the driving part of the device inexpensive. However, to date, a liquid crystal device that does not require a polarizing plate and has the properties (1) to (iii) has not been manufactured.

The inventors of the present invention have conducted intensive studies on the preferred combination of the structure of a liquid crystal device and the chemical structure of the liquid crystal material used in the device, and have found that it can be driven at a much lower voltage than conventional large liquid crystal devices, and that it can be driven with polarized light. We succeeded in producing a liquid crystal device that does not require the use of plates and can be made larger.

(Ninth Means for Solving the Problems) In order to solve the above problems, the present invention provides a first type and a second type of liquid crystal devices described below.

That is, the first type of liquid crystal device according to the present invention has two substrates each having an electrode layer, at least one of which is transparent, and a 9V4 light layer supported between the substrates, and this light control layer has at least the following: A compound of formula (I) or a compound of formula (I
t) and a transparent solid substance, said liquid crystal material forming a continuous phase and said transparent solid substance being dispersed in said liquid crystal material. Features a liquid crystal device.

(In the formula, R represents a linear alkyl group having 1 to 10 carbon atoms.) (hereinafter referred to as the compound of formula 1 (1))
.

A compound represented by the general formula (wherein R represents a linear alkyl group having 1 to 10 carbon atoms) (hereinafter referred to as a compound of formula (II)) In this device, the substrate is made of a rigid material. For example, it may be made of glass, metal, etc., or it may be made of a flexible material such as a plastic film. Two substrates can be placed facing each other with an appropriate distance between them. In addition, at least one of the layers must be transparent so that the light control layer supported between the two layers can be seen from the outside world. However, complete transparency is not required. If the liquid crystal device is to be used to act on light passing from one side of the device to the other, both substrates are provided with suitable transparency. Appropriate transparent or opaque electrodes may be disposed on the entire surface or part of the substrate depending on the purpose.

A liquid crystal material and a transparent solid component are interposed between the two substrates. Incidentally, it is preferable that a spacer for maintaining the distance be interposed between the two substrates according to a conventional method, as in well-known liquid crystal devices.

Liquid crystal materials require the formation of a continuous phase between two substrates. If the ratio of liquid crystal material components is low, it is difficult to form a continuous phase. The proportion of the liquid crystal material in the light control layer components is preferably at least 70% by weight, and even more preferably from 70 to 90% by weight.
% by weight (hereinafter, ``chi'' means % by weight).

The transparent solid component interposed in the continuous phase of this liquid crystal material is
It may be dispersed in the form of particles, but preferably has a three-dimensional network structure. In any case, it is essential to form an optical interface with the liquid crystal material and to cause light scattering to occur. Its transparency can be determined appropriately depending on the purpose of use of the device, and its solidity is not limited to being rigid, but must be flexible, pliable, and elastic as long as it can meet the purpose. Also good. In the case of particles, the particles are too large compared to the wavelength of light, and if they are too small, light scattering properties cannot be expected, but particles of appropriate size and shape can be selected depending on the purpose.

Synthetic resins are suitable as these transparent solid components. Ultraviolet curable monomers or oligomers are preferred as those that provide a three-dimensional network structure.

These liquid crystal devices can preferably be manufactured as follows.

That is, 2 layers having an electrode layer, at least one of which is transparent.
Between the two substrates, the above-mentioned liquid crystal material as essential components and an ultraviolet curable polymer-forming monomer or oligomer,
and a solution consisting of a polymerization initiator, a chain transfer agent, a photosensitizer, a dye crosslinking agent, etc. as optional components, and by irradiating ultraviolet rays through a transparent substrate, thereby polymerizing the monomer or oligomer, This is a method for manufacturing a liquid crystal device in which a liquid crystal material forms a continuous phase and a three-dimensional network-like transparent solid synthetic resin component is dispersed in the liquid crystal continuous phase.

In this method, the ultraviolet curable polymer-forming monomer or oligomer that is an essential component may be one that forms a three-dimensional network in the continuous phase of the liquid crystal material by the irradiated ultraviolet rays. Good examples of polymer-forming monomers are trimethylolpropane triacrylate, tricyclodecane dimethylol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, hexanediol cyacrylate, neopentyl glycol diacrylate,
Tris(acryloxyethyl)isocyanurate and the like.

Similarly, a good example of a polymer-forming oligomer is caprolactone-modified hydroxypiparate ester neopentyl glycol diacrylate.

Optional components include polymerization initiators, chain transfer agents, photosensitizers, dyes, crosslinking agents, etc., and can be appropriately selected depending on the types of monomers, oligomers, etc. and the performance of the desired liquid crystal device. can.

In particular, the combined use of a chain transfer agent can be extremely effective depending on the type of monomer or oligomer, preventing the resin from becoming too cross-linked, thereby making the liquid crystal material more responsive to electric fields, and lowering voltages. Drivability is demonstrated. Examples of chain transfer agents include butanedioldithioglopionate, pentaerythritol tetrakis (β-thiopropionate), triethylene glycol dimercaptan, and the like. The amount of chain transfer agent added varies depending on the type of monomer or oligomer used, but if it is too small, the effect will be weak, and if it is too large, the opacity of the device will decrease and the contrast of the display will deteriorate. The effective amount is believed to be between 0.05 and 30%, with 0.1 and 20% being preferred, based on the weight of the sucrose or oligomer.

In order to support a solution containing each of these components between two substrates, this solution may be injected between the substrates, but it may be applied onto one substrate using a coater such as a spinner. Then, the other substrate may be placed on top of the other substrate.

Curing of an uncured solution can be accomplished by irradiating a suitable dose of ultraviolet light through the transparent substrate. The monomer or oligomer t+ can also be replaced with heat or electron beam depending on the type of optional components.

The thickness of the light control layer is usually adjusted to a range of 5 microns to 30 microns.

The first type of liquid crystal device configured in this manner is capable of time-division driving, which is impossible with conventional droplet dispersion type liquid crystal devices, and is capable of 1/4 duty driving. Furthermore, this liquid crystal device has lower driving voltage, higher contrast, and higher contrast than conventional droplet dispersion type liquid crystal devices.
Moreover, the response speed is fast. For example, while conventional droplet dispersion type liquid crystal devices require a driving voltage of 60 V or more in effective value, often 100 V or more, the first type of liquid crystal device of the present invention requires a driving voltage of approximately 15 V. Start-up response time 3-4m5ee, fall-down response time 3-4m
5ec will be realized.

A second type of liquid crystal device according to the present invention has two substrates each having an electrode layer and at least one of which is transparent, and a light control layer supported between the substrates, wherein the light control layer is made of transparent resin. a matrix and a liquid crystal material dispersed in droplets in the matrix, the liquid crystal material having at least the formula (
A liquid crystal device characterized in that it is a nematic liquid crystal material containing a compound of I) or a compound of formula (If) or a mixture thereof.

In this liquid crystal device, examples of resin materials used for the transparent resin matrix of the light control layer include alkali-soluble acrylic resin, alkali-soluble I
Water-soluble resins such as polyester resins and polyvinyl alcohol resins; Solvent-free curable resins such as two-part curable epoxy resins and unsaturated polyester resins; Electron beam curable resins such as epoxy acrylates, polyester acrylates, polyurethane acrylates, and polyether acrylates. There are resins and UV-curable resins thereof.

In this liquid crystal device, in order to form a light control layer on a substrate, (1) prepare a dispersion liquid in which a liquid crystal material is finely dispersed in an aqueous solution of the water-soluble resin, and apply this liquid on the substrate and dry it. (2) A method of applying a dispersion in which a liquid crystal material is finely dispersed in the above-mentioned solvent-free curable resin onto a substrate and curing and drying it; Any of the following methods may be employed: finely dispersing a liquid crystal material, applying a nine-dispersion liquid onto a substrate, and curing and drying it by irradiating it with electron beams or ultraviolet rays.

The light control layer formed by these methods is a layer in which a liquid crystal material is finely dispersed in a resin matrix. The thickness of this light control layer is typically adjusted to a range of 10 microns to 300 microns, and the droplet size of the liquid crystal material is typically adjusted to a range of 0.1 microns to 30 microns.

Materials similar to those used in the first type of liquid crystal device described above can be used for the substrate, but in this second type of liquid crystal f high speed, at least one of the two substrates is made by the following method. It can also be formed. That is, a light control layer is formed on one of the substrates by the above method, and then an electrode layer is formed on this light control layer by vacuum deposition, sputter deposition, printing, or other methods, and further, as necessary. , by painting, film laminating or other methods.
This is a method of forming a protective film on this electrode layer.

The second type of liquid crystal D4 chair formed in this manner has a lower driving voltage, greater contrast, and faster response speed than the conventional droplet dispersion type liquid crystal D4 chair.

(Example) Examples of the present invention will be shown below to further specifically explain the present invention. However, the present invention is not limited to these examples.

Example 1 Trimethylolproz4' as a polymer-forming monomer
7 Triacrylate 19.8% by weight (the same applies below).

As a polymerization initiator, 2-hydroxy-2-methyl-1-phenylpronon-1-one was used at 0.21 O! 80% of the liquid crystal (A) described below was mixed as a HQ crystal material, a small amount of alumina powder with an average particle size of 10 μm was added as a spacer, and the mixture was heated at 20°C.
It was inserted between two MX20 ITO glass plates and irradiated with ultraviolet rays to harden (polymerize) the monomer. The curing conditions were as follows: the liquid crystal device was cured using metal halide dolan f (8
0 W/cIIi) at a speed of 3.5 ny&in, and irradiated with ultraviolet rays. The energy given is 50
Corresponds to 0 mJ/cIn. The electrode spacing of the device is 1
It is 1μ. When a cross section of the light control layer formed between two glass plates was observed using a scanning electron microscope, a three-dimensional polymer network was observed.

The resulting liquid crystal device has a threshold voltage of vjO
” v * vq. 1 3. OV,
= 17: / Toko 2 St 1: 20° rise response time 2.5 m□□□, fall response time 4 m
The number of 5ec time division lines was Nm□4.9.

(1) Liquid crystal (At transition temperature 68.5℃ (N-I) <-25℃
(C-N) Refractive index n=1.787 n=1.533 Δn=0.254 Threshold voltage 1.15V (vth) Viscosity at 20°C 59 e, p.

(2) Number of time division drive lines %II! =((α2+ 1
)/(α2 1)) However, α=v,. /v1゜(3) The light transmittance of the device when no voltage is applied is 04,
If the light transmittance does not change as the applied voltage increases and the assumed light transmittance is 100 inches, then the applied voltage at which the light transmittance becomes 90 inches is V. , the applied voltage when the light transmittance becomes 10 cm is V. shall be.

(Effects of the Invention) As described above, the present invention is a large-area, thin-film liquid crystal device that can be driven at a low voltage of about 15V, and has a short start-up response time even at such a low voltage. 3-4
It has a high response speed of m5ec, a high transparent-opaque contrast of about 1=20, has a threshold value, and is capable of time-division driving of 1/47' NE. Therefore, it is extremely easy to adjust lighting, adjust visibility, and make large displays for advertisements, etc., and furthermore, such liquid crystal devices can be manufactured extremely easily and at low cost.

Agent Patent Attorney Katsutoshi Takahashi Procedural Amendment (voluntary) December 73, 1988 Director General of the Patent Office Yoshi 1) Moon Yi 1, Indication of the case 1988 Patent Application No. 80439 2, Title of the invention Liquid crystal device 3. Relationship with the case of the person making the amendment Patent applicant address: 3-35-58 Sakashita, Itabashi-ku, Tokyo 174 (288
) Dainippon Ink & Chemicals Co., Ltd. Representative: Materials: Shigekuni (1 idiot) 4. Agent Address: 3-7-20 Nihonbashi, Chuo-ku, Tokyo 103 Dainippon Ink & Chemicals Co., Ltd. Phone: Tokyo (03) 272- 4511 (Major representative) (8
876) Patent Attorney Takahashi Katsutoshi 5, Claims column of the specification to be amended and Detailed Description of the Invention column 6, Contents of the amendment (1) The claims are amended as shown in the attached sheet.

(2) At the 21 locations shown in the table below in the specification "Base" to "substrate" Correct each.

(3) "Substrate and this substrate" in the second line of page 10 of the specification is corrected to "substrate and this substrate."

(4) "Substrate and this substrate" in page 16, line 18 of the specification is corrected to "substrate and this substrate J."

Above attached claims (Japanese Patent Application No. 63-80439) 1, two substrates having an electrode layer and at least one of which is transparent;
A nematic comprising a light control layer supported between LOs, the light control layer containing a compound represented by the general formula (wherein R represents a linear alkyl group having 1 to 10 carbon atoms) A liquid crystal device comprising a liquid crystal material and a transparent solid substance, characterized in that the liquid crystal material forms a continuous phase and the transparent solid substance is dispersed in the liquid crystal material.

2. Two ILs, at least one of which has an electrode layer and is transparent
and a light control layer supported between the river, and the light control layer comprises a compound represented by the general formula (wherein R represents a linear alkyl group having 1 to 10 carbon atoms). 1. A liquid crystal device comprising a nematic liquid crystal material containing a nematic liquid crystal material and a transparent solid substance, wherein the liquid crystal material forms a continuous phase and the transparent solid substance is dispersed in the liquid crystal material.

3. It has a light control layer supported between two sheets of light, at least one of which has an electrode layer and is transparent, and the above-mentioned ③] is a general formula (wherein R is a carbon atom number of 1 to 10 A nematic liquid crystal material containing a compound represented by the general formula (wherein R represents a linear alkyl group having 1 to 10 carbon atoms). and a transparent solid material, the liquid crystal material forming a continuous phase, and the transparent solid material being dispersed in the liquid crystal material.

4. Two ILs, at least one of which has an electrode layer and is transparent
and a light control layer supported between the two layers, the light control layer consisting of a transparent resin matrix and a liquid crystal material dispersed in the matrix, and the liquid crystal material having the general formula ( (In the formula, R represents a linear alkyl group having 1 to 10 carbon atoms.) A liquid crystal device characterized in that it is a nematic liquid crystal material containing a compound represented by the following formula.

5. Two substrates, at least one of which is transparent, each having an electrode layer, and a light control layer supported between the IL, wherein the light control layer is dispersed in a transparent resin matrix in a small pattern in the matrix. The liquid crystal material is a nematic liquid crystal material containing a compound represented by the general formula (wherein R represents a linear alkyl group having 1 to 10 carbon atoms). LCD device.

6. A light control layer supported between two panels, at least one of which is transparent, having an electrode layer; The liquid crystal material comprises a compound represented by the general formula (wherein R represents a linear alkyl group having 1 to 10 carbon atoms); represents a linear alkyl group having 1 to 1 o carbon atoms.) A liquid crystal device characterized in that it is a nematic liquid crystal material containing a compound represented by:

7. The liquid crystal device according to claim 1.2 or 3, wherein the liquid crystal material accounts for 70% by weight or more of the components of the light control layer.

8.i3 The liquid crystal device according to claim 1.2 or 3, wherein the bright solid substance is made of a synthetic resin.

9. The liquid crystal device according to claim 1.2 or 3, wherein the transparent solid substance is dispersed in the liquid crystal material in the form of particles or a three-dimensional network.

10. The liquid crystal device according to claim 1.2 or 3, wherein the light control layer has a thickness of 5 to 30 microns.

11. A liquid crystal device according to claim 1.2 or 3, wherein the droplets of liquid crystal material dispersed in the resin matrix have an average particle size of 0.1 to 30 microns.

Claims (1)

[Scope of Claims] 1. Two substrates each having an electrode layer, at least one of which is transparent, and a light control layer supported between the substrates, wherein the light control layer has a general formula ▲ mathematical formula, chemical formula, or table. etc. ▼ (In the formula, R represents a linear alkyl group having 1 to 10 carbon atoms.) Consisting of a nematic liquid crystal material containing a compound represented by the following and a transparent solid substance, the liquid crystal material is continuous A liquid crystal device, characterized in that the transparent solid substance forms a phase and is dispersed in the liquid crystal material. 2. It has two substrates with electrode layers, at least one of which is transparent, and a light control layer supported between these substrates, and the light control layer has a general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (Formula (wherein, R represents a linear alkyl having 1 to 10 carbon atoms.) A nematic liquid crystal material containing a compound represented by A liquid crystal device, characterized in that a solid substance is dispersed in the liquid crystal material. 3. It has two substrates with electrode layers, at least one of which is transparent, and a light control layer supported between these substrates, and the liquid crystal layer has a general formula ▲ mathematical formula, chemical formula, table, etc. ▼ (formula (In the formula, R represents a linear alkyl group having 1 to 10 carbon atoms.) Compounds represented by the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R represents a straight chain alkyl group having 1 to 10 carbon atoms. (representing a straight-chain alkyl group) consisting of a nematic liquid crystal material containing a compound represented by A liquid crystal device characterized by: 4. Two substrates having an electrode layer, at least one of which is transparent, and a light control layer supported between the substrates, wherein the light control layer is formed in a transparent resin matrix and in the form of droplets in this matrix. A compound consisting of a dispersed liquid crystal material, where the liquid crystal material is represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (wherein R represents a linear alkyl group having 1 to 10 carbon atoms) A liquid crystal device characterized by being a nematic liquid crystal material containing. 5. Two substrates having electrode layers, at least one of which is transparent, and a light control layer supported between the substrates, the light control layer comprising a transparent resin matrix and droplets formed in the matrix. A compound consisting of a dispersed liquid crystal material, where the liquid crystal material is represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (wherein R represents a linear alkyl group having 1 to 10 carbon atoms) A liquid crystal device characterized by being a nematic liquid crystal material containing. 6. Two substrates having an electrode layer, at least one of which is transparent, and a light control layer supported between the substrates, wherein the light control layer is formed in a transparent resin matrix and in the form of droplets in this matrix. A compound consisting of a dispersed liquid crystal material, where the liquid crystal material is represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (wherein R represents a linear alkyl group having 1 to 10 carbon atoms) It is a nematic liquid crystal material containing a compound represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R represents a linear alkyl group having 1 to 10 carbon atoms.) Characteristic LCD device. 7. The liquid crystal device according to claim 1, 2 or 3, wherein the liquid crystal material accounts for 70% by weight or more of the components of the light control layer. 8. The liquid crystal device according to claim 1, 2 or 3, wherein the transparent solid substance is made of a synthetic resin. 9. The liquid crystal device according to claim 1, 2 or 3, wherein the transparent solid substance is dispersed in the liquid crystal material in the form of particles or a three-dimensional network. 10. The liquid crystal device according to claim 1, 2 or 3, wherein the light control layer has a thickness of 5 to 30 microns. 11. A liquid crystal device according to claim 4, 5 or 6, wherein the droplets of liquid crystal material dispersed in the resin matrix have an average particle size of 0.1 to 30 microns.