JP2001350163A - Optical element and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element excellent in color developing characteristics or light scattering characteristics in swelling and capable of obtaining excellent contrast ratio, and to provide a method for manufacturing the optical element. SOLUTION: In the optical element consisting of at least a pair of substrates 2 and 4, stimulus responsive polymeric gels 6 and liquid 8 absorbable in the stimulus responsive polymeric gels 6, the rate of the area of the orthogonal projection onto the substrate 2 of all the stimulus responsive polymeric gels 6 fixed to the substrate 2 as a mono particle layer to the effective area of the substrate 2 contributing to light modulation is 70% or more during color developing or color scattering. In the method for manufacturing the optical element having at least a stage for fixing the stimulus responsive polymeric gels onto the substrate and a stage for filling the space between the substrates with the liquid absorbable in the stimulus responsive polymeric gels, the stimulus responsive polymeric gels are fixed onto the substrate with a swelling quantity smaller than the swelling quantity during light developing or light scattering.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element capable of reversibly controlling light transmittance, light scattering, and the like in response to an external stimulus, and a method of manufacturing the same. More specifically, the present invention relates to a recording and display material, an optical element and a sensor for controlling the amount of transmitted light, an optical element that can be used as a dimming element such as dimming glass, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a polymer gel which reversibly changes in volume (swelling / shrinking) due to pH change, ionic strength change, adsorption and desorption of chemical substances, solvent composition change, or application of heat, light, electrical stimulation, etc. There is known a technique of controlling light transmission and scattering by using a material (stimulus-responsive polymer gel) to perform light control and color development.

[0003] For example, as a technique for controlling the amount of transmission or scattering of light containing no dye, Japanese Patent Application Laid-Open No. 61-151621 discloses a technique.
In Japanese Patent Application Laid-Open No. 62-925 and Japanese Patent Application Laid-Open No. 62-925, the display is controlled by controlling the light scattering property by changing the refractive index difference from the solvent due to swelling / shrinking of the polymer gel that absorbs and desorbs the liquid due to temperature change. Devices that do this have been proposed. In addition, Japanese Patent Application Laid-Open
Japanese Patent Application Publication No. 7-95325 discloses an element which performs display by changing the light scattering property of a polymer gel which absorbs and emits a liquid by electrical stimulation. .P by undoping
Japanese Patent Application Laid-Open No. 5-188354 discloses an element that performs display by changing the light scattering property of a polymer gel by changing the H.
Swelling of polymer gel that absorbs and releases liquids by the action of an electric field
There has been proposed an element that controls the state of blocking, reflecting, scattering, or transmitting light by shrinkage to perform cloudy / transparent display.

On the other hand, as a technique for controlling a coloring state including a dye, Japanese Patent Application Laid-Open No. 61-149926 discloses a technique in which a polymer gel which absorbs and absorbs a liquid by the action of an electric field and a coloring liquid in which a pigment is dispersed in the liquid. There has been proposed an optical element made of a composition combining the above, and discloses a technique for performing display by moving a colored liquid by changing the shape of a polymer gel. Further, Japanese Patent Application Laid-Open Nos.
No. 927 proposes a device using a colored polymer gel, in which the optical density decreases when the polymer gel swells and the polymer gel is colored when the polymer gel shrinks. Japanese Patent Application Laid-Open No. 4-274480 proposes an element which uses a polymer gel to which a dye is bound and performs display by changing the optical density by the volume change. Further, in Japanese Patent Application Laid-Open No. 9-160081, a substantially white display is obtained when the polymer gel swells by utilizing the shape change of the polymer gel adsorbed on the surface of the pigment fine particles or the colored fine particles, and the polymer gel shrinks. In some cases, an element has been proposed in which the color of pigment fine particles or colored fine particles is displayed to change the hue by changing the volume of the polymer gel.

The present inventors have proposed a novel coloring material in JP-A-11-236559 as a coloring material having excellent contrast. This color-forming material is a composition and a color-forming material containing a pigment having a saturation absorption concentration or higher in a polymer gel that swells and shrinks due to absorption and release of a liquid due to the application of a stimulus. When this occurs, the light absorption efficiency decreases due to local aggregation of the pigment, and the composition as a whole becomes light transmissive. On the other hand, when the polymer gel swells, the pigment is diffused throughout the composition, so that the light absorption efficiency is improved and the composition is in a colored state.

The present inventors have also disclosed in Japanese Patent Application No. 11-3066.
In the specification of No. 6, a proposal was made regarding a composition and a light modulating material containing a light scattering member having a saturation scattering concentration or more in a polymer gel which swells and shrinks due to absorption and release of a liquid by applying a stimulus. I have. When the polymer gel shrinks, the light modulating material is reduced in light scattering efficiency due to local aggregation of the light scattering member, and becomes light transmissive as a whole composition.
On the other hand, when the polymer gel swells, the light scattering member is diffused throughout the composition to improve the light scattering efficiency, and the composition becomes cloudy.

The present inventors have also disclosed in Japanese Patent Application Laid-Open No. 2000-472.
No. 67, a pigment having a saturated absorption concentration or more or a light scattering member having a saturation scattering concentration or more is contained in a polymer gel which swells and contracts due to absorption and release of a liquid by applying a stimulus, and the polymer gel contains fibers. Compositions and light modulating materials that are fixed to a porous substrate are proposed. Fixing the gel in this way requires coagulation of the gel due to repeated swelling and shrinking,
That is, it is possible to prevent deterioration at the time of coloring and to stably obtain an initial contrast.

However, the various dimming and display element technologies proposed in the above publications specifically disclose how the polymer gel is arranged on the substrate and how it is fixed. It has not been. Thus, as a result of repeated studies by the present inventors, it has been found that there are the following problems.
That is, various problems occur depending on the state when the polymer gel is immobilized on the substrate. One is that when a polymer gel that changes its volume in response to an external stimulus is immobilized as a single particle layer on a substrate in a contracted state, high stress is generated due to the lateral stress between the polymer gels that occurs during swelling. There is a problem that the fixing point of the molecular gel with the material to be immobilized is damaged, the polymer gel is peeled off, and a sufficient coloring density cannot be obtained. Further, the polymer gel,
When a single particle layer is immobilized on a substrate in a swollen state that forms a colored state, a gap is generated between the polymer gels due to repulsive force generated between the polymer gels, steric factor, flow in the swelling solution, and the like, There is a problem that it cannot be fixed at a high occupation ratio and good color-forming properties cannot be obtained.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and achieve the following objects. That is, the present invention provides an optical element that uses a stimuli-responsive polymer gel that repeats swelling and shrinkage, has excellent coloration properties or light scattering properties upon swelling, and provides a good contrast ratio, and a method for producing the same. Aim.

[0010]

Means for solving the above problems are as follows. That is, <1> at least consists of a pair of substrates, a stimuli-responsive polymer gel, and a liquid that can be absorbed in the stimuli-responsive polymer gel, and contributes to light control during color development or light scattering. The ratio of the area of the orthographic projection of all the stimuli-responsive polymer gels immobilized as a single particle layer on the substrate to the effective area of the substrate on the substrate (hereinafter, referred to as “occupancy”) ) Is 70% or more. <2> A method for producing an optical element, comprising at least a step of immobilizing a stimulus-responsive polymer gel on a substrate and a step of filling a liquid absorbable in the stimulus-responsive polymer gel between the substrates. Wherein the stimulus-responsive polymer gel is immobilized on the substrate with an amount of swelling smaller than the amount of swelling during color development or light scattering. <3> The production of the optical element according to <2>, wherein the stimulus-responsive polymer gel is immobilized on the substrate with a swelling amount of 5 to 30% by weight smaller than the swelling amount at the time of coloring or light scattering. Is the way.

[0011] Further, means for solving the above problems include:
The following embodiments are preferred. <4> The optical element according to <1>, wherein the stimulus-responsive polymer gel contains a coloring material or a light scattering member. <5> The optical element according to <4>, wherein the stimulus-responsive polymer gel contains a colorant having a saturation absorption concentration or higher when the gel is contracted. <6> The optical element according to <4>, further comprising a light scattering member having a saturated light scattering concentration or more when the stimuli-responsive polymer gel shrinks.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. [Optical element] The optical element of the present invention comprises at least a pair of substrates, a stimuli-responsive polymer gel, and a liquid that can be absorbed in the stimuli-responsive polymer gel. Other members such as an application unit and a spacer are provided.

First, regarding the configuration of the optical element of the present invention,
This will be described with reference to the drawings. FIG. 1 is a schematic sectional view showing an example of the optical element of the present invention. The optical element shown in FIG. 1 includes a stimulus-responsive polymer gel 6 and an absorption in the stimulus-responsive polymer gel 6 between two substrates 2 and 4, at least one of which is transparent. The liquid 8 is filled, and the surrounding area is sealed by a sealing material 16 such as an adhesive, an ultraviolet curable resin, or a thermosetting resin so that the stimulus-responsive polymer gel 6 and the absorbable liquid 8 do not flow out. Have been. The stimulus-responsive polymer gel 6 is fixed to one of the two substrates 2 and 4 with a single particle layer so that the occupation ratio during color development or light scattering is 70% or more. Stimulation means 10 and 12 are provided on two opposite surfaces of the two substrates 2 and 4. The stimulus applying means is not essential, but is preferably provided on at least one side and, if necessary, on both sides. Stimuli-responsive polymer gel 6
Is preferably fixed to the surface of the substrate provided with the stimulus applying means.

The optical element of the present invention is characterized in that the occupancy of the swelling state stimuli-responsive polymer gel in color development or light scattering, that is, the effective area of the substrate contributing to dimming, is one particle layer on the substrate. The ratio of the area of the orthogonal projection area of all the stimuli-responsive polymer gels immobilized as
% Or more. In addition, the time of color development or light scattering refers to the time when the stimulus-responsive polymer gel immobilized on the optical element of the present invention swells and develops color or light scattering.

Here, the effective area of the substrate contributing to dimming and the area of the orthographic projection of the stimuli-responsive polymer gel onto the substrate will be described with reference to FIG. FIG. 2 is a schematic plan view showing one example of the optical element of the present invention. Although not shown in FIG. 2, the stimuli-responsive polymer gels 6 are actually arranged densely in the inner square so that gaps are reduced. Each shaded circle in FIG. 2 represents the area of the orthogonal projection of one stimulus-responsive polymer gel particle, and each circle without the hatching represents the area of the orthogonal projection of one spacer. . The area of the orthogonal projection of all the stimuli-responsive polymer gels immobilized as a single particle layer on the substrate onto the substrate is the sum of the areas of all the hatched circles in FIG. Means The effective area of the substrate contributing to dimming is the area of the substrate that covers the area where all the stimuli-responsive polymer gels are arranged.In other words, the effective area of the substrate is arranged on the outermost side. It is the area of the region formed by connecting the tangents of the orthogonally projected circle of the stimulus-responsive polymer gel, and means the area of the inner square in FIG.

The method for measuring the occupancy according to the present invention is as follows. First, a cell in which a stimuli-responsive polymer gel is immobilized on a substrate is observed from a vertical direction at a predetermined magnification with a microscope, and photographed with a CCD camera. The obtained image is P
Analysis is performed on C to obtain a histogram in which the horizontal axis indicates color gradation and the vertical axis indicates density. The threshold values of the stimuli-responsive polymer gel and the substrate are determined from this histogram, and the area of the stimuli-responsive polymer gel portion is measured to determine the occupancy of the polymer gel on the substrate.

The principle of coloring and decoloring of the present invention is based on the volume change of a stimulus-responsive polymer gel containing a coloring material or a light scattering member. Therefore, the higher the volume ratio of the polymer gel at the time of swelling and at the time of shrinking, the higher the contrast can be obtained. In addition, considering individual states, the higher the shrinkage amount of the stimuli-responsive polymer gel at the time of contraction, that is, the smaller the volume at the time of contraction, the higher the characteristics can be exhibited. On the other hand, regarding the swelling state, not only is the swelling amount of each stimuli-responsive polymer gel large, but also the stimuli-responsive polymer gel It is effective to increase the area occupied by.

Therefore, in order to obtain effective optical characteristics as the optical element of the present invention, it is necessary that the occupancy of the stimulus-responsive polymer gel in a swollen state is 70% or more, preferably 80%. That is all. When the occupancy of the swelling state stimuli-responsive polymer gel is less than 70%, a large amount of light passes through the region where the stimuli-responsive polymer gel including the coloring material or the light scattering member does not exist, and the stimulus-responsive polymer is increased. Even if the optical properties of the gel itself are sufficiently high, a high color-developed state or a light-scattered state cannot be obtained as a whole of the optical element. Therefore, according to the configuration of the present invention, when a coloring material is contained in the stimulus-responsive polymer gel, the optical element obtains a high optical density due to the high light absorption efficiency of each stimulus-responsive polymer gel when swollen. be able to. Further, when a light scattering member is contained in the stimulus-responsive polymer gel, the optical element can obtain a high light scattering amount due to the high light scattering efficiency of each stimulus-responsive polymer gel when swollen. . Furthermore, when the stimulus-responsive polymer gel shrinks, the optical absorption efficiency and light scattering efficiency are extremely low, and the optical density and light scattering amount are high due to swelling and shrinkage due to the characteristics of each stimulus-responsive polymer gel. Contrast can be realized.

Since the stimulus-responsive polymer gel applied to the present invention is fixed to the substrate surface, it prevents aggregation of the polymer gel during contraction, and re-swells the substrate surface again at the same 70% as before the contraction. It can be covered with the above occupancy. Therefore, from such an element configuration, the present optical element can repeatedly and stably obtain a change in optical density and a change in light scattering amount.

(Stimuli-Responsive Polymer Gel) The stimuli-responsive polymer gel that can be used in the optical element of the present invention contains a coloring material or a light scattering member as necessary. As the stimulus-responsive polymer gel, a composition of a coloring material and a liquid disclosed in Japanese Patent Application Laid-Open No. 11-236559 invented by the present inventors is particularly preferable. Further, as a stimuli-responsive polymer gel containing a light scattering member, Japanese Patent Application No.
The composition of a light scattering material having a saturated scattering concentration or higher and a liquid disclosed in Japanese Patent No. 666 is preferably used.

The stimuli-responsive polymer gel usable in the optical element of the present invention includes energy such as heat, light, electricity, and magnetism, pH change, oxidation / reduction, ion concentration change, adsorption and desorption of chemical substances, A stimulus-responsive polymer gel that absorbs and releases a liquid by various stimuli such as a change in the solvent composition and reversibly changes in volume (swelling and shrinking) is preferable.

Specifically, as the polymer gel which responds to a stimulus by a pH change due to an electrode reaction or the like, an electrolyte-based polymer gel is preferable, and a cross-linked product of poly (meth) acrylic acid or a salt thereof; And (meth) acrylamide, hydroxyethyl (meth) acrylate, (meth)
Cross-linked products of copolymers with alkyl acrylates and the like and salts thereof; cross-linked products of copolymers of maleic acid with (meth) acrylamide, hydroxyethyl (meth) acrylate, alkyl (meth) acrylate and the like Salts; cross-linked products of polyvinyl sulfonic acid and salts thereof; cross-linked products of copolymers of vinyl sulfonic acid and (meth) acrylamide, hydroxyethyl (meth) acrylate, alkyl (meth) acrylate, and salts thereof; polyvinyl benzene Crosslinked product of sulfonic acid and its salt; Crosslinked product of vinylbenzenesulfonic acid and (meth) acrylamide, hydroxyethyl (meth) acrylate, alkyl (meth) acrylate, etc. and its salt; polyacrylamide alkyl sulfone Crosslinked acid or salt thereof; acrylamide alkyl sulfone And (meth) acrylamide, hydroxyethyl (meth) acrylate, (meth) crosslinked product of the copolymer of acrylic acid alkyl esters and salts thereof;
Crosslinked product of polydimethylaminopropyl (meth) acrylamide and its salt; polydimethylaminopropyl (meth)
A crosslinked product of a copolymer of acrylamide and (meth) acrylamide, hydroxyethyl (meth) acrylate, alkyl (meth) acrylate, or a salt or quaternary product; polydimethylaminopropyl (meth) acrylamide and polyvinyl alcohol; Cross-linked products of
Graded product; crosslinked product of a complex of polyvinyl alcohol and poly (meth) acrylic acid or a salt thereof; crosslinked product of a carboxyalkylcellulose salt; partially hydrolyzed product of a crosslinked product of poly (meth) acrylonitrile, a salt thereof, and the like. Can be

As the polymer gel which responds to stimulus by adsorption and desorption of a chemical substance such as a surfactant by an electric field, a strongly ionic polymer gel is preferable, and a crosslinked product of polyvinylbenzenesulfonic acid or vinylbenzenesulfonic acid and (meth) Acrylamide, hydroxyethyl (meth) acrylate,
A crosslinked product of a copolymer with an alkyl (meth) acrylate or the like; a crosslinked product of a polyacrylamide alkylsulfonic acid or acrylamidoalkylsulfonic acid and (meth) acrylamide, hydroxyethyl (meth) acrylate,
A crosslinked product of a copolymer with an alkyl (meth) acrylate or the like may be used. These are used in combination with a cationic surfactant such as an alkylpyridinium salt such as n-dodecylpyridinium chloride, an alkylammonium salt, a phenylammonium salt, and a phosphonium salt such as tetraphenylphosphonium chloride.

As the polymer gel which responds to stimulation by oxidation / reduction by electricity, a cationic polymer gel is preferable, and a crosslinked product of polyamino-substituted (meth) acrylamide such as polydimethylaminopropylacrylamide; polydimethylaminoethyl (meth) Acrylate; polydiethylaminoethyl (meth) acrylate; crosslinked product of amino-substituted alkyl ester of poly (meth) acrylate such as polydimethylaminopropyl (meth) acrylate; crosslinked product of polystyrene; crosslinked product of polyvinylpyridine; crosslinked product of polyvinylcarbazole A crosslinked product of polydimethylaminostyrene, and the like. These are used as a CT complex (charge transfer complex) in combination with an electron accepting compound. The electron-accepting compound preferably used at this time includes benzoquinone; 7,7,8,8-tetracyanoquinodimethane (TCNQ); tetrabutylammonium perchlorate; tetracyanoethylene; chloranil; trinitrobenzene; Iodine and the like;

Polymer gels that respond to stimulation by application of heat include crosslinked polymers having an LCST (lower critical solution temperature) and IPNs (interpenetrating network structures) of two-component polymer gels that form hydrogen bonds with each other. Is preferred. The former has the property of shrinking at high temperatures, and specifically,
Crosslinked product of poly N-alkyl-substituted (meth) acrylamide such as poly-N-isopropylacrylamide; N-alkyl-substituted (meth) acrylamide and (meth) acrylic acid or a metal salt thereof, (meth) acrylamide, alkyl (meth) acrylate Crosslinked products of copolymers with esters and the like; crosslinked products of polyvinyl methyl ether; crosslinked products of alkyl-substituted cellulose derivatives such as methylcellulose, ethylcellulose and hydroxypropylcellulose.

On the other hand, the latter has the property of swelling at a high temperature. Specifically, the latter comprises a crosslinked product of poly (meth) acrylamide and a crosslinked product of poly (meth) acrylic acid.
It is composed of a PN body and its partially neutralized product (a partially acidified acrylic acid unit is metallized), a crosslinked product of a copolymer containing poly (meth) acrylamide as a main component and a crosslinked product of poly (meth) acrylic acid. Examples thereof include an IPN compound and a partially neutralized product thereof. Among these compounds, a cross-linked product of a poly-N-alkyl-substituted alkyl amide, an IPN product composed of a cross-linked product of a poly (meth) acrylamide and a cross-linked product of poly (meth) acrylic acid and a partially neutralized product thereof are preferably used. Can be

As the polymer gel which responds to stimulus by the application of light, a crosslinked product of a hydrophilic polymer compound having a molecular structure which is ion dissociated by light, such as a triarylmethane derivative or a spirobenzopyran derivative, is preferred. Specific examples include a crosslinked product of a copolymer of a vinyl-substituted triarylmethane leuco derivative and (meth) acrylamide.

Examples of the polymer gel that responds to the stimulus by applying a magnetic field include ferromagnetic particles and a crosslinked product of polyvinyl alcohol containing a magnetic fluid. However, the polymer gel itself is not particularly limited. What is necessary is just to be contained in the category of a polymer gel. As the polymer gel which responds by a change in the composition of the solution or a change in the ionic strength, the above-mentioned electrolyte polymer gel can be preferably applied.

In the present invention, each stimuli-responsive polymer gel may be used alone, or a plurality of polymer gels may be used in combination. The above description using parentheses indicates both a compound not containing the prefix in the parenthesis and a compound containing the same. For example, the description of (meth) acrylic acid means
It means acrylic acid and methacrylic acid. The volume change of the polymer gel used in the present invention is desirably at least a volume ratio of 5 or more, preferably 10 or more. If the volume ratio is less than 5, sufficient light control contrast may not be obtained.

The shape of the stimulus-responsive polymer gel is not particularly limited, and various shapes such as a particle shape, a block shape, a film shape, an irregular shape, and a fiber shape can be used. Among them, the particulate form is particularly preferable because of its characteristics such as high speed of volume change (responsiveness) to various stimuli and wide application range. There is no particular limitation on the form in the form of particles, but a sphere, an ellipsoid, a cube, a polyhedron, a porous body, a star,
Needles, hollows, etc. can be applied. In the case of particles, the preferred size is in the range of 0.1 μm to 5 mm, more preferably 1 μm to 1 mm in average particle size in the contracted state.
mm. If the average particle diameter is less than 0.1 μm, problems such as difficulty in handling the particles and inability to obtain excellent optical properties arise. On the other hand, if the average particle diameter is larger than 5 mm, problems such as a significantly slow response time required for a volume change occur.

These particles can be obtained by a method of pulverizing a polymer gel by a physical pulverization method, a method of forming a polymer gel before cross-linking into particles by a chemical pulverization method, and then forming a polymer gel by crosslinking. Alternatively, it can be produced by a general method of particle polymerization such as emulsion polymerization, suspension polymerization, and dispersion polymerization. In order to further increase the volume change rate of the polymer gel due to various stimulus responses, it is also preferable to make the material porous and improve the ease of liquid inflow and outflow, as in the prior art of the polymer gel. Generally, the swollen polymer gel can be made porous by freeze-drying or the like.

The stimulus-responsive polymer gel can be variously changed in volume by applying the stimulus as described above in the presence of an absorbable liquid in the stimulus-responsive polymer gel. For example, in the case of a thermoresponsive polymer gel,
By applying radiant heat such as light or heat, in the case of an electrically responsive polymer gel, pH changes due to electrode reactions or by ion adsorption or electrostatic action by an electric field; The volume can be largely changed by absorbing and releasing the liquid by the structural change.

(Absorptive liquid) The liquid which can be absorbed in the stimuli-responsive polymer gel is not particularly limited,
Preferably, water, aqueous electrolyte solution, alcohols, ketones, esters, ethers, dimethylformamide,
Dimethylacetamide, dimethylsulfoxide, acetonitrile, propylene carbonate, etc., xylene,
Aromatic solvents such as toluene and mixtures thereof can be used. In addition, the absorbable liquid includes a surfactant that absorbs and desorbs to the stimulus-responsive polymer gel, a redox agent such as a viologen derivative for promoting a change in pH of the liquid, an acid, an alkali, a salt, and a surfactant. And a stabilizer such as an antioxidant and an ultraviolet absorber.

When the polymer constituting the stimulus-responsive polymer gel is not cross-linked, a liquid in which this polymer can be dissolved can be preferably used. A preferred mixing ratio of the stimulus-responsive polymer gel to the absorbable liquid is 1: 2000 to 1: 1 (stimulus-responsive polymer gel: absorbable liquid).

(Coloring Material) As the coloring material contained in the stimulus-responsive polymer gel, various pigments and dyes can be applied. For example, various black pigments such as carbon black (channel black, furnace black, etc.) and black dye nigrosine compounds, and color pigments such as benzidine-based yellow pigments, quinacridone-based, rhodamine-based magenta pigments, and phthalocyanine-based cyan pigments And the like. More specifically, compounds represented by a condensed azo compound, an isoindolinone compound, an anthraquinone compound, an azo metal complex, a methine compound, and an allylamide compound are used as the yellow pigment. Specifically, for example, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83,
93, 94, 95, 109, 110, 111, 128,
129, 147, 168 and the like are preferably used.

Examples of the magenta pigment include a condensed azo compound,
Diketopyrrolopyrrole compound, anthraquinone, quinacridone compound, basic dye lake compound, naphthol compound, benzimidazolone compound, thioindigo compound,
A perylene compound is used. Specifically, for example, C.I. I. Pigment Red 2, 3, 5, 6,
7, 23, 48: 2, 48: 3, 48: 4, 57: 1,
81: 1, 144, 146, 166, 169, 177,
184, 185, 202, 206, 220, 221, 2
54 is particularly preferred.

As the cyan pigment, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds and the like can be used. Specifically, for example, C.I. I. Pigment Blue 1, 7, 15, 1
5: 1, 15: 2, 15: 3, 15: 4, 60, 62,
66 and the like can be particularly preferably used.

As the dye, for example, C.I. I. Direct Yellow 1, 8, 11, 12, 24, 26, 2
7, 28, 33, 39, 44, 50, 58, 85, 8
6, 87, 88, 89, 98, 157, C.I. I. Acid Yellow 1, 3, 7, 11, 17, 19, 23, 2
5, 29, 38, 44, 79, 127, 144, 24
5, C.I. I. Basic Yellow 1, 2, 11, 34,
C. I. Food yellow 4, C.I. I. Reactive Yellow 37, C.I. I. Solvent Yellow 6, 9, 17,
31, 35, 100, 102, 103, 105, C.I.
I. Direct Red 1, 2, 4, 9, 11, 13, 1
7, 20, 23, 24, 28, 31, 33, 37, 3,
9, 44, 46, 62, 63, 75, 79, 80, 8
1, 83, 84, 89, 95, 99, 113, 197,
201, 218, 220, 224, 225, 226, 2
27, 228, 229, 230, 231, C.I. I. Acid Red 1, 6, 8, 9, 13, 14, 18, 26,
27, 35, 37, 42, 52, 82, 85, 87, 8
9, 92, 97, 106, 111, 114, 115, 1
18, 134, 158, 186, 249, 254, 28
9, C.I. I. Basic Red 1, 2, 9, 12, 1
4, 17, 18, 37, C.I. I. Food red 14,
C. I. Reactive Red 23, 180, C.I. I. Solvent Red 5, 16, 17, 18, 19, 22, 2
3,143,145,146,149,150,15
1, 157, 158,

C. I. Direct Blue 1, 2, 6, 1
5, 22, 25, 41, 71, 76, 78, 86, 8
7, 90, 98, 163, 165, 199, 202,
C. I. Acid Blue 1, 7, 9, 22, 23, 2
5, 29, 40, 41, 43, 45, 78, 80, 8
2, 92, 93, 127, 249, C.I. I. Basic Blue 1, 3, 5, 7, 9, 22, 24, 25, 26,
28, 29, C.I. I. Food blue 2, C.I. I. Solvent Blue 22, 63, 78, 83-86, 191, 1
94, 195, 104, C.I. I. Direct Black 2, 7, 19, 22, 24, 32, 38, 51, 56,
63, 71, 74, 75, 77, 108, 154, 16
8, 171, C.I. I. Acid Black 1, 2, 7, 2
4, 26, 29, 31, 44, 48, 50, 52, 9
4, C.I. I. Basic Black 2, 8, C.I. I. Food black 1, 2, C.I. I. Reactive Black 3
1, C.I. I. Food violet 2, C.I. I. Solvent Violet 31, 33, 37, C.I. I. Solvent Green 24, 25, C.I. I. Solvent Brown 3,
9 and the like. These pigments and dyes may be used alone or may be used in combination to obtain a desired color. However, from the viewpoint of weather resistance, it is more preferable to use a pigment than a dye.

(Light Scattering Member) As the light scattering member contained in the stimuli-responsive polymer gel, a material having a refractive index different from that of a liquid absorbable in the stimuli-responsive polymer gel is preferable. However, other than that, there is no particular limitation, and various inorganic compounds and organic compounds can be applied.

Specific examples of the inorganic compound include zinc oxide, basic lead carbonate, basic lead sulfate, lead sulfate, lithobon,
Muscovite, zinc sulfide, titanium oxide, antimony oxide, lead white, zirconium oxide, alumina, mycanite, mycarex, quartz, calcium carbonate, gypsum, clay, silica, silicic acid, silicon earth, talc, basic magnesium carbonate, Inorganic oxides such as alumina white, gloss white, satin white, zinc, alumel, antimony, aluminum, aluminum alloy, iridium, indium, osmium, chromium, chromel, cobalt, zirconium, stainless steel, gold, silver, nickel silver, copper , Bronze, tin, tungsten, tungsten steel, iron, lead, nickel, nickel alloy, nickeline, platinum, platinum rhodium, tantalum, duralumin, nichrome, titanium, Krupp austenitic steel, constantan, brass, platinum iridium, palladium, palladium Alloy, molybdenum, molybdenum steel, manganese, manganese alloys, rhodium, a metal material such as rhodium metal, ITO (indium tin oxide) inorganic conductive materials such like.

Further, specific examples of the organic compound include:
Phenolic resin, furan resin, xylene / formaldehyde resin, urea resin, melamine resin, aniline resin,
Alkyd resin, unsaturated polyester, epoxy resin, polyethylene, polypropylene, polystyrene, poly-p
-Xylylene, polyvinyl acetate, acrylic resin, methacrylic resin, polyvinyl chloride, polyvinylidene chloride, fluoroplastic, polyacrylonitrile, polyvinyl ether, polyvinyl ketone, polyether, polycarbonate, thermoplastic polyester, polyamide, diene plastic, polyurethane Polymer materials such as plastics, polyphenylene, polyphenylene oxide, polysulfone, aromatic heterocyclic polymers, silicone, natural rubber-based plastics, cellulose-based plastics, and mixtures (polymer blends) of these two or more polymer materials. Can be

Further, a polymer material containing the light scattering materials listed above can be used as the light scattering member. The polymer material is not particularly limited, and various polymer resins can be used. Specific examples of preferred polymer resins include the specific examples listed when the light-scattering material is an organic compound.

There are no particular restrictions on the shape of the pigment as the coloring material and the light scattering member.
Various shapes such as a film shape, an irregular shape, and a fiber shape can be used. Among them, the particulate form is particularly preferable because of its high color developing properties and light scattering properties and its wide application range. There is no particular limitation on the form in the form of particles, but a sphere,
Cubes, ellipsoids, polyhedrons, porous bodies, stars, needles, hollows, scales and the like can be applied. The preferred size of the particles is 0.01 to 500 μm in average particle diameter.
m, more preferably in the range of 0.05 to 100 μm. This is because when the average particle diameter is less than 0.01 μm or more than 500 μm, the coloring effect and light scattering effect required for the pigment and the light scattering member are reduced. Further, when the average particle diameter is less than 0.01 μm, outflow from the inside of the polymer gel to the outside is likely to occur. Further, these particles can be produced by a general physical pulverization method or a chemical pulverization method.

In these pigments and light-scattering members, an acid group such as a carboxyl group or a sulfonic acid group in the molecule,
Those having polar groups such as a hydroxyl group, an amino group, a thiol group, a halogen group, a nitro group, a carbonyl group, and the like that easily form an aggregate when the concentration of a pigment or a light scattering member is high in a polymer gel are also preferable. used. It is preferable that the pigment or the light-scattering member is contained in the stimulus-responsive polymer gel and does not flow out of the polymer gel. In order to prevent the pigment or light scattering member from flowing out, use a pigment or light scattering member having a particle size larger than the network of the polymer gel to be used, or use electrical, ionic, or other physical Using a pigment or a light-scattering member having a high natural interaction, or using a pigment or a light-scattering member whose surface is chemically modified. Examples of the coloring material or light scattering member whose surface is chemically modified include, for example, those in which a group that chemically bonds to a stimulus-responsive polymer gel is introduced into the surface, and pigments or light scattering members onto which a polymer material is grafted. .

When a dye is selected as a coloring material, a material having a particularly high light absorption coefficient is preferred. In addition, since it is preferable that the dye is contained in the stimulus-responsive polymer gel and does not flow out of the polymer gel, a reactive dye or the like into which a group chemically bonded to the polymer gel is introduced is particularly preferably applied. It is preferable that the concentration of the coloring material contained in the stimulus-responsive polymer gel reaches a concentration equal to or higher than the saturation absorption concentration in at least a part of the polymer gel when the polymer gel shrinks. Here, “above the saturation absorption density” is a density at which the light absorption efficiency per unit color material is reduced in a state where the color material density is sufficiently high. If the definition of “saturated absorption density or more” is expressed by another characteristic, the color material concentration is such that the relationship between the color material density and the light absorption amount under a specific optical path length deviates greatly from the linear relationship. . In other words, when the color material concentration becomes equal to or higher than the saturation absorption concentration, the light absorption efficiency per particle or molecule of the color material decreases, and the light absorption amount is not proportional to the color material concentration. Light absorption amount. On the other hand, below the saturation absorption concentration, the light absorption amount is proportional to the color material concentration, and the light absorption efficiency per color material particle or molecule is almost constant. Therefore, when the coloring material is contained in the stimuli-responsive polymer gel at a saturation absorption concentration or higher, light can be efficiently absorbed at the time of swelling, and the light absorption amount can be increased as compared with the time of contraction.

When the stimulus-responsive high molecular gel is shrunk and the coloring material is contained so as to have a saturation absorption concentration or higher, the swelling of the high molecular gel lowers the coloring material concentration and reduces the concentration of the coloring material per particle or molecule. Can increase the light absorption efficiency. As a result, it is possible to greatly increase the amount of light absorption when swelling and to greatly reduce the amount of light absorption when contracting. On the other hand, when the concentration of the coloring material to be contained is equal to or less than the saturation absorption concentration, the light absorption efficiency per particle of the coloring material at the time of swelling is almost the same as at the time of contraction. As a result, the amount of light absorbed during swelling is greatly increased,
At the time of contraction, the amount of light absorption cannot be greatly reduced.
From the above, the saturated absorption density is a density necessary for increasing the change in the amount of light absorption due to swelling and shrinkage, and the display contrast can be increased by setting the color material density to be equal to or higher than the saturation absorption density. .

The concentration of the coloring material contained in the stimuli-responsive polymer gel required to have such properties depends on the particle diameter, refractive index, extinction coefficient, specific gravity, etc. of the coloring material, but is generally used. 3 to 9 colorants on dry stimulus-responsive polymer gel
The content is preferably in the range of 5% by weight, more preferably in the range of 5 to 80% by weight. Color material content is 3
When the amount is less than 10% by weight, a change in the amount of color development due to a change in the volume of the stimuli-responsive polymer gel does not appear, and in order to obtain a sufficient dimming contrast, a problem such as an increase in the thickness of the optical element may occur. is there. On the other hand, if the concentration of the coloring material exceeds 95% by weight, the swelling / shrinking of the stimuli-responsive polymer gel becomes difficult to progress with good response, and the stimulus response characteristics and volume change of the optical element may be reduced. .

The concentration of the light-scattering member contained in the stimulus-responsive polymer gel is also determined based on a similar argument to the concentration of the colorant, at least when the polymer gel shrinks. It is preferable that the concentration reaches a concentration equal to or higher than the saturation scattering concentration in part. Here, “at least the saturated scattering concentration” means that, as one index, the average distance between the light scattering members is sufficiently short, and the light scattering function of the light scattering members is a primary particle. Is the concentration at which the efficiency of light scattering decreases. Such a state in which the light scattering member exhibits collective light scattering characteristics is referred to as a state in which the concentration of the light scattering member is equal to or higher than the saturation scattering concentration. If the definition of “saturated scattering concentration or more” is expressed by another characteristic, the light scattering member concentration at which the relationship between the light scattering member concentration and the amount of light scattering under a specific optical path length deviates greatly from the relationship of the linear line. It is.

In order to achieve the above-mentioned saturated scattering concentration or more in the contracted state of the stimulus-responsive polymer gel, it depends on the particle size, refractive index, electric conductivity, specific gravity, etc. of the light scattering member. Generally, the light scattering member is preferably contained in the stimulus-responsive polymer gel in a dry state in the range of 2 to 95% by weight, more preferably 5 to 95% by weight. When the content of the light scattering member is less than 2% by weight, the change in the amount of light scattering due to the change in volume of the stimuli-responsive polymer gel does not appear, and the thickness of the optical element increases in order to obtain a sufficient contrast. Etc. may occur. on the other hand,
When the content of the light scattering member exceeds 95% by weight, swelling / shrinking of the stimuli-responsive polymer gel becomes difficult to progress with good response, and the stimulus response characteristics and volume change of the optical element may be reduced. .

The stimulus-responsive polymer gel may contain a coloring material or a light-scattering member by a method of uniformly dispersing and mixing the coloring material or the light-scattering member in the polymer before crosslinking, and then by crosslinking after polymerization, or A method of adding a coloring material or a light scattering member to the polymer precursor composition and polymerizing the polymer precursor composition can be applied. When a coloring material or a light scattering member is added at the time of polymerization, it is also preferable to use a coloring material or a light scattering member having a polymerizable group or an unpaired electron (radical) as described above, and to chemically bond them. Further, it is preferable that the coloring material and the light scattering member are dispersed as uniformly as possible in the stimulus-responsive polymer gel. In particular, when dispersing in a polymer, it is preferable to uniformly disperse using a mechanical kneading method, a stirring method, or a dispersant.

(Substrate) The substrate on which the stimuli-responsive gel or the absorbable liquid is sandwiched may be an acrylic resin such as polyester, polyimide, polyolefin, poly (methyl meth) acrylate, polystyrene, polypropylene, polyethylene, nylon, or polystyrene. Films such as vinyl chloride, plate-like substrates, glass substrates, metals, ceramics and the like can be used. The thickness of the substrate is preferably 10 μm to 2 mm, but the size can be selected variously depending on the purpose, and is not particularly limited.

(Other members)-Stimulus providing means-The stimulus providing means used in the present invention is selected from those capable of providing a stimulus suitable for the stimulus-responsive polymer gel filled therein. Therefore, for example, when an electrically responsive polymer gel is used, an electrode is provided, and when a thermally responsive polymer gel is used, a heating resistor is provided. The stimulus applying means preferably used in the present invention is mainly an electrode for applying an electric stimulus. Regarding the configuration of the electrodes, either a simple matrix electrode type or a divided electrode type for each pixel can be applied.

Specifically, when electrical stimulation is applied,
Electrodes composed of metal films represented by copper, aluminum, silver, gold, nickel, platinum, etc., metal oxides represented by tin oxide-indium oxide (ITO), polypyrroles, polythiophenes, polyanilines, polyphenylenevinylenes , An electrode made of a conductive polymer represented by polyacenes, polyacetylenes, and the like, and an electrode made of a composite material of the polymer and the above-mentioned metal or metal oxide particles are preferably used. These electrode configurations may be wired for simple matrix driving, but switching elements such as thin film transistor (TFT) elements or two-terminal elements such as MIM elements and varistors can also be provided.

When applying heat as a stimulus,
A combination of the electrode and a metal typified by a Ni—Cr compound or the like, a metal oxide such as tantalum oxide or ITO, or a heating resistor such as carbon is preferably used. In addition, in addition to the above, light or a magnetic field,
A layer for providing an electromagnetic field or the like can be provided.

-Sealant- The sealant has the ability to suppress the evaporation or volatilization of the solvent from the light modulating material, has adhesion to the substrate, and does not adversely affect the characteristics of the light modulating material. Any material may be used as long as it satisfies these conditions for a long time under actual use conditions. It is also possible to combine a plurality of sealing materials.

As the sealing material and the sealing method, one-layer sealing is preferable in consideration of securing the opening area of the color display element, processing cost by simplifying the process, and the like. As a sealing material when performing sealing with one layer, a thermosetting elastic sealing material mainly composed of an isobutylene oligomer having a reactive group at a terminal,
Use of an acrylic ultraviolet curable resin or the like can be exemplified. When sealing with two layers, a polyisobutylene-based sealant can be used for the primary sealing in contact with the light control material, and an acrylic resin or the like can be used for the secondary sealing. The sealing material and the sealing method in the present invention are not limited to the above examples, and various types can be selected, and they may be used in combination.

-Spacer- A sufficiently uniform gap is secured inside the optical element of the present invention in order to sandwich the stimulus-responsive polymer gel and the absorbable liquid in the stimulus-responsive polymer gel. It is sufficient if necessary to use as little spacer as possible so as not to cause image defects. The distance between the substrates by the spacer is selected from 1 μm to 5 mm, and more preferably 10 μm to 200 μm for a small optical element. If the thickness is less than 1 μm, the amount of light control becomes small, and if it exceeds 5 mm, there is a problem that the element becomes heavy. At this time, the shape of the spacer is not particularly limited as long as the gap can be stably maintained, but the spacer is preferably an independent shape such as a sphere, a cube, or a column. In addition, a spacer having a continuous shape can be used. In this case, the spacer may have a function of segmenting the inside of the light control layer by forming a mesh while maintaining the gap. By doing so,
The effect of suppressing malfunction of adjacent pixels is obtained, and the display image quality is further improved. The continuous shape of the spacer is not particularly limited as long as the gap can be stably maintained, and various shapes including a polygonal shape such as a lattice shape or a honeycomb shape can be mainly applied. In the case where the function of segmenting the inside of the optical element is provided, the lattice shape is most preferable in consideration of the shape of the pixel and the shape of the stimulating means.
The spacer is not particularly limited as long as it is a material that is stable to a liquid that can be absorbed in the stimuli-responsive polymer gel. For example, a resin, a metal, a metal oxide, glass, or the like can be used.

[Method of Manufacturing Optical Element] In the method of manufacturing an optical element of the present invention, at least a step of immobilizing a stimuli-responsive polymer gel on a substrate and a step of absorbing the stimuli-responsive polymer gel into the substrate. Filling the liquid between the substrates, and immobilizing the stimulus-responsive polymer gel on the substrate with a swelling amount smaller than the swelling amount at the time of coloring or light scattering. According to the method for manufacturing an optical element of the present invention, the optical element of the present invention having the above configuration can be suitably manufactured. That is, according to the optical element manufacturing method of the present invention, the stimulus-responsive polymer gel is placed on the substrate such that the occupancy of the stimulus-responsive polymer gel during coloring or light scattering is 70% or more. It can be suitably immobilized as a single particle layer. The formation of a single particle layer can be preferably achieved by chemically bonding the substrate and the stimuli-responsive polymer gel, and then washing off the unnecessary stimuli-responsive polymer gel with a solvent.

In the present invention, it is preferable that the above-mentioned stimuli-responsive polymer gel is immobilized on the above-mentioned substrate at a swelling amount smaller than that at the time of coloring or light scattering by 5 to 30% by weight. If the change in the swelling amount is less than 5% by weight, it may be difficult to make the occupancy of the swelling state stimuli-responsive polymer gel in color development or light scattering 70% or more. If it exceeds 30% by weight, the stress in the lateral direction between adjacent stimuli-responsive polymer gels at the time of swelling is large, which may damage the fixing portion and peel off the polymer gel.

The swelling amount of the stimuli-responsive polymer gel at the time of coloring or light scattering and the swelling amount of the stimuli-responsive polymer gel at the time of immobilization on a substrate can be obtained by the following equations, respectively. . Swelling amount = (W _SW −W _d ) / W _d Here, W _SW represents the weight of the stimulus-responsive polymer gel at the time of swelling (at the time of coloring or light scattering, or at the time of immobilization on a substrate). , W _d represent the dry weight. The weight W _SW at the time of swelling of the stimuli-responsive polymer gel becomes a steady state by immersing a fixed amount of the dried gel (weight W _d ) in a solution in which the ion concentration, pH, solvent composition, temperature, etc. are changed. It can be obtained by measuring the weight at the time. Therefore, the swelling amount of the stimuli-responsive polymer gel when immobilized on the substrate is controlled so as to be 5 to 30% by weight smaller than the swelling amount of the stimuli-responsive polymer gel at the time of coloring or light scattering. After that, the stimulus-responsive polymer gel is preferably immobilized on a substrate.

The amount of swelling at the time of immobilization can be controlled by changing the ionic concentration, pH, solvent composition, temperature, electric field, etc. of the solution at the time of immobilization. For example, the swelling amount of an ionic polymer gel can be generally adjusted by pH, salt concentration or solution composition. Therefore, when used as an optical element, the amount of swelling that is 5 to 30% by weight smaller than the amount of swelling during color development or light scattering can be obtained by setting pH, salt concentration, and solution composition under appropriate conditions. it can.

For a polymer gel that responds to stimulus by a change in pH, a salt concentration of 10 to 10 is used in a solution having a pH of 3 to less than 7, and for a polymer gel that swells and contracts due to a change in salt concentration.
It is preferable to adjust the amount of swelling in a solution of ^{-7 to} 5 × 10 ^-1 mol / l. In addition, in the case of a polymer gel that responds to a stimulus by the application of heat, for example, in a polymer gel having the property of swelling at a low temperature, the temperature is set to about 2 to 10 ° C. higher than the temperature at which a saturated swelling state is reached. In a polymer gel having the property of swelling at a high temperature, an appropriate swelling state can be obtained by setting the temperature at about 2 to 10 ° C. lower than the temperature at which the saturated swelling state is reached.

For example, in the case of an ionic polymer gel having an ionic functional group such as a carboxyl group or a sulfone group at the terminal, particularly in a solution having a pH of 3 to less than 7 or a salt concentration of 1
It is preferably carried out in a solution of 0 ^{-7 to} 5 × 10 ^-1 mol / l. However, when the pH of the solution is less than 3 or the salt concentration exceeds 5 × 10 ⁻¹ mol / l, the stimuli-responsive polymer gel shrinks too much to obtain a desired swelling state. On the other hand, when the pH of the solution is 7 or more, the range of pH at which a desired swelling state is obtained is narrow, that is, the swelling amount change depending on the pH change is steep, and stable production is difficult. On the other hand, if the salt concentration is less than 10 ^-7 mol / l, the desired swelling state cannot be obtained because swelling can hardly be achieved.

Adjustment of pH and salt concentration includes hydrochloric acid, sulfuric acid, sodium hydrogen sulfate, potassium hydrogen sulfate, phosphoric acid, sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, It can be carried out by adding sodium hydrogen carbonate, potassium hydrogen carbonate, sodium chloride, potassium chloride, sodium sulfate, potassium sulfate, sodium phosphate, potassium phosphate and the like. The amount of swelling can be controlled by the solvent type (composition). Water, aqueous electrolyte solution, alcohols, ketones, esters, ethers, dimethylformamide,
Dimethylacetamide, dimethylsulfoxide, acetonitrile, propylene carbonate, etc., xylene,
Aromatic solvents such as toluene and mixtures thereof can be used. A desired swelling amount can be obtained by appropriately adjusting the mixing ratio.

The immobilization of the stimuli-responsive polymer gel used in the present invention on the substrate is performed in a desired swelling state of the stimuli-responsive polymer gel, and chemical immobilization such as chemical bonding is preferably applied. . Various chemical bonds such as an ionic bond, a hydrogen bond, and a covalent bond can be considered as the chemical bond. Among them, a covalent bond is most preferable in terms of stability, and the chemical bond is formed by a reaction using various immobilizing agents.

Examples of the polymer gel immobilizing agent used in the present invention include compounds having two or more polymerizable unsaturated groups, reactive functional groups and the like. Examples of the compound having two or more polymerizable unsaturated groups include di- or tri (meth) acrylic polyols such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin polyoxyethylene glycol, polyoxypropylene glycol, and polyglycerin. Acid esters, unsaturated polyesters obtained by reacting the polyols with unsaturated acids such as maleic acid and fumaric acid, bis (meth) acrylamides such as N, N'-methylenebis (meth) acrylamide, tris Di (meth) acrylate carbamates obtained by reacting polyisocyanate such as diisocyanate and hexamethylene diisocyanate with hydroxyethyl (meth) acrylate, allylated starch, allylated cellulose, diallyl phthalate, Other polyvalent allyls such as tetraallyloxyethane, pentaneerythritol triallyl ether, trimethylolpropane triallyl ether, diethylene glycol diallyl ether, triallyl trimethyl ether and the like can be mentioned. Among these, the present invention includes ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, N, N'-methylenebis (meth) acrylamide Are preferably used.

Examples of the compound having two or more reactive functional groups include a diglycidyl ether compound, a haloepoxy compound, and di- and triisocyanate compounds. Specific examples of the diglycidyl ether compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerin diglycidyl ether, polyglycerin diglycidyl ether, and the like. . In addition, specific examples of the haloepoxy compound include epichlorohydrin, epibromohydrin, β-methylepichlorohydrin and the like. Further, specific examples of the diisocyanate compound include 2,4-tolylene diisocyanate, hexamethylene diisocyanate, and the like.

Also, vinyl silane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-amino Amino-based silane coupling agents such as propyltrimethoxysilane and 3-aminopropyltrimethoxysilane; 3-glycidoxypropyltrimethoxysilane;
-Glycidoxypropylmethyldimethoxysilane, 2-
Various reactive silane coupling agents, such as an epoxy silane coupling agent such as (3,4-epoxycyclohexyl) ethyltrimethoxysilane, can also be applied. Among them, the present invention particularly relates to N- (2-aminoethyl) 3-
Aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane,
An amino silane coupling agent such as 3-aminopropyltrimethoxysilane is preferably used.

The polymer gel immobilizing agent is dissolved in water or an organic solvent, or a mixed solution thereof, and is usually 0.01 to
It is used as 10% by weight, more preferably 0.1 to 5% by weight. Here, as the organic solvent, methanol, ethanol, IPA, toluene, benzene, acetone, TH
F, methyl cellosolve and the like can be used. If the amount of the immobilizing agent is less than 0.01% by weight, the stimuli-responsive polymer gel cannot be sufficiently immobilized, while if it exceeds 10% by weight, a uniform thin immobilizing agent is immobilized on the surface of the substrate to be immobilized. May not be formed, and the immobilization of the stimuli-responsive polymer gel may be too strong or non-uniform, resulting in a problem that desired optical characteristics may not be obtained.

Next, the stimulus-responsive polymer gel is immobilized by first immersing the substrate in an aqueous solution of an immobilizing agent,
The reactive functional group is introduced into the surface of the substrate by reacting at room temperature for about 10 hours, or by immersing the substrate and withdrawing it and reacting at room temperature or high temperature for about 1 minute to 10 hours. Then, the functional group introduced into the substrate side is reacted with the functional group present in the molecular structure of the stimuli-responsive polymer gel to complete the immobilization process. At this time, the functional groups in the stimulus-responsive polymer gel may be subjected to a treatment, if necessary, to increase the reaction activity. Specific examples include treatments such as addition of an acid catalyst and addition of an aqueous carbodiimide solution.

[0072]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples. (Example 1) A stimulus-responsive polymer gel containing a light scattering member was produced as follows. 10 g of N-isopropylacrylamide, 0.02 g of N, N′-methylenebisacrylamide as a cross-linking agent, and 0.2% of 2-hydroxyethyl acrylate for introducing hydroxyl groups used for immobilization.
g was dissolved in 50 g of distilled water, and a stainless steel powder having an average primary particle diameter of 3 μm (refractive index: 0.1 μm) was used as a light scattering member.
8) An aqueous solution was prepared by stirring and mixing 10 g. The above aqueous solution was placed in a flask, oxygen was removed by purging with nitrogen, 0.04 g of ammonium persulfate as a polymerization initiator was added, and the mixture was heated at 60 ° C. for 10 hours to perform polymerization.

After completion of the polymerization, the resulting polymer gel mass was pulverized with a homogenizer, poured into a large amount of distilled water, and filtered to repeat the operation of purification, whereby purification was performed. afterwards,
After dehydration using a large amount of acetone, the solvent was replaced with cyclohexane, and then dried. The dried polymer gel particles had a particle size of about 70 μm. The dried polymer gel particles are added to a large amount of distilled water to swell,
The water absorption during equilibrium swelling at 5 ° C. was about 50 g / g. Then, it was found that when the water-swelled polymer gel particles were heated to 50 ° C., they contracted and exhibited a water absorption of about 3 g / g. That is, it was confirmed that the resin shrinks at a temperature higher than the phase transition point and swells at a temperature lower than the phase transition point.
This change was reversible, and the swelling and shrinking resulted in a change in particle size of 2.6 times, that is, about 17 times in volume. As described above, a stimuli-responsive polymer gel that swells and shrinks with temperature changes was produced.

The above polymer gel particles (3.0 g) were added to 200 g of distilled water to swell. When this is heated to 28 ° C., the polymer gel shrinks, and the water absorption at this time is about 40 g /
g, which was about 20% by weight smaller than the swelling amount at the time of light scattering. Put this dispersion in a Teflon vat,
With stirring, tetramethylammonium chloride 0.1.
02 g was added.

The substrate treatment for immobilizing the polymer gel particles was performed by ultrasonically cleaning a 10 × 10 cm slide glass (Matsunami Glass: # 0200) with acetone and isopropyl alcohol for 30 minutes and then using acetic acid. PH
5 in 200 ml of a 95% aqueous ethanol solution adjusted to 5
4 ml of glycidoxypropyltrimethoxysilane was immersed in a solution prepared by adding under stirring for 30 minutes. After the taken-out substrate was washed with methanol, it was left in an oven at 150 ° C. for 1 hour to cure the silane layer. The polymer gel particle dispersion solution was uniformly applied onto the silane-coupled substrate, and then allowed to stand for about 10 hours to be fixed.

Next, several 300 μm spacers were arranged between the polymer gels on the slide glass, and this sample was sandwiched by another slide glass to form a cell. The inside of the cell was filled with distilled water. At this time, no detachment or flow of the polymer gel particles due to stress or the like between the polymer gel particles was observed, and the polymer gel particles were stably immobilized. The cell was observed with a microscope at a magnification of 550 from the vertical direction, and photographed with a CCD camera. The obtained image is analyzed on a PC, and the horizontal axis represents the color gradation,
A histogram whose vertical axis indicates the density was obtained. Determine the threshold value of the polymer gel and slide glass from the histogram,
When the area of the polymer gel portion was measured, the polymer gel occupancy on the substrate was about 85%. The transmittance was in an opaque state of about 10% or less, indicating high light scattering efficiency. In addition, the cells in which the polymer gel particles are immobilized
Upon heating to 0 ° C., the polymer gel particles shrank and the transmittance increased to 80%. The swelling / shrinking change due to the temperature change was reversible, and even after repeating about 100 times, the polymer gel did not peel off.

Example 2 A stimulus-responsive polymer gel containing a pigment was prepared by reversed-phase suspension polymerization as follows. 20.0 g of acrylic acid was taken as a main monomer in a beaker, 33 g of a 25% by weight aqueous sodium hydroxide solution was added dropwise while cooling and stirring, and about 74% of neutralization was performed. A solution dissolved in pure water, 10.0 g of a phthalocyanine-based blue pigment as a pigment for gel coloring, and 0.1 g of methylene bisacrylamide as a cross-linking agent were added, and the mixture was sufficiently stirred, followed by emulgen 909 (manufactured by Kao Corporation). 1) was added to prepare a homogeneous solution. The obtained solution was added to a solution obtained by dissolving 5.0 g of a sorbitol-based surfactant (Solgen 50, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as a dispersion stabilizer in 500 g of cyclohexane in a beaker and replacing with nitrogen, and rotary stirring. 1 with feather
The mixture was emulsified by high-speed stirring at 0000 rpm for 10 minutes.

Next, the temperature of the reaction system was adjusted to 25 ° C., and a 50% cyclohexane solution of N, N, N ′, N′-tetramethylethylenediamine was added while stirring the solution.
Polymerization was performed. After polymerization, the resulting colored polymer gel particles are collected, and after performing a neutralization reaction with an aqueous sodium hydroxide solution, repeatedly washed with pure water and dehydrated with acetone,
Let dry. The obtained particles were classified to have an average particle size of about 4
μm stimuli-responsive polymer gel particles were obtained. The colored polymer gel particles had a pure water absorption of about 200 g / g, and could be reversibly swelled and shrunk by pH change. 3.0 g of the obtained dried polymer gel particles was added to 200
g of distilled water, add a small amount of hydrochloric acid and adjust the pH.
Adjusted to 5. At this time, the water absorption of the polymer gel particles was about 160 g / g, which was about 20% by weight smaller than the swelling amount at the time of color development. Then, 1-ethyl-3- [3-
0.1 g of (dimethylamino) propyl] carbodiimide.hydrochloride (EDC.HCl) was added to the solution with stirring to obtain a polymer gel particle dispersion.

Next, the processing of the substrate for fixing the stimulus-responsive polymer gel particles will be described. A glass plate (10 × 10 cm) with an ITO (indium-tin oxide) electrode was ultrasonically washed with acetone and isopropyl alcohol for 30 minutes each, and 4 ml of γ-aminopropyltriethoxysilane was stirred in 200 ml of a 95% aqueous solution of ethanol while stirring. It was immersed in the prepared solution for 30 minutes. After the substrate taken out was lightly washed with methanol, it was left in an oven at 150 ° C. for 1 hour to cure the silane layer. The polymer gel particle dispersion solution was uniformly applied onto the silane-coupled substrate, and then allowed to stand for about 10 hours to be fixed.
The polymer gel particle-immobilized substrate obtained had a polymer gel in a swelling state in pure water at pH 7, but the polymer gel particles were not detached due to stress or the like, and could be stably immobilized.

Next, several 200 μm spacers are inserted into the IT
This sample was sandwiched between the polymer gels on the O glass and the cells were provided with an interval, and another ITO glass was used to form a cell. The inside of the cell was filled with a 0.001 mol / l aqueous sodium chloride solution. In this state, the pigment inside the cell is blue due to the swelling of the polymer gel particles, and the optical density measurement device (X-Rite40 manufactured by X-Rite) is used.
When measured in the cyan mode of 4), the optical density was as high as 2.0. This cell was photographed with a CCD camera in the same manner as in Example 1, and the image was processed on a PC. As a result, the polymer gel occupancy on the substrate was about 90%.

Next, when a DC voltage of 5 V is applied between the glass electrodes using the electrode on the substrate side on which the polymer gel particles are immobilized as a cathode, the polymer gel particles are instantaneously shrunk,
Optical density decreased to 0.3. Thereafter, when a voltage having a polarity opposite to that of the color erasing reaction was applied, the color changed to blue again, and it was confirmed that the color developing / color erasing reaction occurred reversibly. This reversible concentration change could be repeated stably 50 times or more.

Example 3 A stimulus-responsive polymer gel containing a pigment was produced by reversed-phase suspension polymerization as follows. 20.0 g of acrylic acid was taken as a main monomer in a beaker, 33 g of a 25% by weight aqueous sodium hydroxide solution was added dropwise while cooling and stirring, and about 74% of neutralization was performed. A solution dissolved in pure water and carbon black (Showa Black N762, manufactured by Showa Cabot Corporation) 1 as a pigment for gel coloring
0.0 g and 0.1 g of methylene bisacrylamide as a cross-linking agent were added, and the mixture was sufficiently stirred to obtain Emulgen 909.
1 g (manufactured by Kao Corporation) was added to prepare a uniform solution. The obtained solution is added to cyclohexane 50 in a beaker.
A solution of 5.0 g of a sorbitol-based surfactant (Solgen 50, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as a dispersion stabilizer was added to 0 g of the solution, and the solution was added to a solution purged with nitrogen.
The mixture was emulsified by high-speed stirring at 00 rotation for 10 minutes.

Next, the temperature of the reaction system was adjusted to 25 ° C., and a 50% cyclohexane solution of N, N, N ′, N′-tetramethylethylenediamine was added while stirring the solution.
Polymerization was performed. After the polymerization, the produced colored polymer gel particles were recovered, neutralized with an aqueous sodium hydroxide solution, and then repeatedly washed with pure water and dried. The obtained particles were classified to obtain stimulus-responsive polymer gel particles having an average particle size of about 4 μm. The colored polymer gel particles had a pure water absorption of about 200 g / g. After swelling 4.0 g of the obtained dried polymer gel particles with 200 g of distilled water, a slight amount of acid was added to adjust the pH to 5. The water absorption at this time was about 160 g / g. This dispersion solution was placed in a Teflon (registered trademark) vat, and 1-ethyl-3- [3
0.1 g of [-(dimethylamino) propyl] carbodiimide.hydrochloride (EDC.HCl) was added to the solution with stirring to obtain a polymer gel particle dispersion.

Next, in the treatment of the substrate for immobilizing the stimulus-responsive polymer gel particles, a 10 × 10 cm Nesa glass (Asahi Glass: U film) was subjected to ultrasonic cleaning with acetone and isopropyl alcohol for 30 minutes each. After that, 4 ml of γ-aminopropyltriethoxysilane was added to 200 ml of a 95% aqueous ethanol solution with stirring, and the resulting solution was added with
Immerse for 30 minutes. After the taken-out substrate was washed with methanol, it was left in an oven at 150 ° C. for 1 hour to cure the silane layer. After uniformly applying the polymer gel particle dispersion on the silane-coupled substrate,
It was left stationary for about 10 hours to immobilize it.

Next, several 200 μm spacers were arranged between the polymer gels on the Nesa glass to provide an interval, and another spacer was formed.
This sample was sandwiched between sheets of Nesa glass to form a cell. The inside of the cell was filled with a 0.001 mol / l aqueous sodium chloride solution. In this state, the pigment inside the cell is black due to the swelling of the polymer gel particles, and the Vis of the optical density measuring device (X-Rite 404) is used.
When measured in the ual mode, the optical density was 1.8. Even at this time, no detachment or flow of the polymer gel particles due to stress or the like between the polymer gel particles was observed, and the polymer gel particles were stably immobilized. An image obtained by observing the cell at a magnification of 550 with a microscope was processed on a PC in the same manner as in Example 1. As a result, the polymer gel occupancy on the substrate was about 85%.

Next, a voltage of 5 V was applied between both Nesa glass electrodes using the electrode on the substrate side on which the polymer gel particles were immobilized as a cathode.
When the DC voltage was applied, the polymer gel particles were instantaneously shrunk and discolored. At this time, the optical density was about 0.4. Thereafter, when a voltage having a polarity opposite to that of the decoloring reaction was applied, the color was changed to black again, and it was confirmed that the coloring and decoloring reactions occurred reversibly. This reversible concentration change could be repeated stably 50 times or more.

Comparative Example 1 Polymer gel particles 3.0 containing a light-scattering member in a dry state, obtained in the same manner as in Example 1.
g was swollen with 200 g of distilled water to obtain a polymer gel dispersion solution. When the solvent temperature was adjusted to 35 ° C., the water absorption of the polymer gel particles at this time was about 11 g / g, which was a swelling amount smaller by about 78% by weight than the swelling amount at the time of light scattering.
A glass substrate treated in the same manner as in Example 1 was immersed in this dispersion solution, and allowed to react at 35 ° C. for 10 hours to perform immobilization.

Although the polymer gel particles on the substrate are swollen in distilled water at a temperature of 25 ° C., a large amount of polymer gel particles are observed to be detached due to stress between the polymer gel particles generated at the time of swelling. Was. This substrate is placed under a microscope for 5 minutes.
When the image observed at a magnification of 50 times was processed on a PC in the same manner as in Example 1, the polymer gel occupancy on the substrate was 50%.
It was below. This substrate was clearly uneven even when visually observed, and did not show good light scattering performance. This is because the polymer gel particles were fixed in a contracted state at a temperature of 35 ° C., so that a large amount of polymer gel particles were detached by the stress of the polymer gel particles during swelling, and many gaps were formed between the gels. It is because it has been done.

Comparative Example 2 3.0 g of the pigment-containing polymer gel particles in a dry state obtained by the same method as in Example 2 was used.
After swelling with 200 g of pure water, sodium chloride was added to adjust to 1.0 mol / l. At this time, the amount of water absorbed by the polymer gel particles was about 70 g / g, which was about 65% by weight smaller than the amount of swelling during color development. Thereafter, 0.1 g of 1-ethyl-3- [3- (dimethylamino) propyl] carbodiimide.hydrochloride (EDC.HCl) was added to the solution with stirring to obtain a polymer gel particle dispersion. A substrate subjected to silane coupling treatment in the same manner as in Example 2 was immersed in this polymer gel dispersion solution, and allowed to stand for about 10 hours to obtain an immobilized substrate.

The obtained polymer gel particle-immobilized substrate was made of p
The polymer gel is swollen in pure water of H7,
The detachment of a large amount of particles was observed due to the stress between the polymer gel particles generated during swelling. This substrate is examined with a microscope 5
When the image observed at a magnification of 50 times was processed on a PC in the same manner as in Example 1, many gaps were generated between the polymer gel particles, and the polymer gel occupancy on the substrate was 50% or less. Met. Optical density measuring device (manufactured by X-Rite: X-
When measured in the Visual mode of Rite 404), the optical density was about 0.9, and good color-forming properties could not be obtained.

Comparative Example 3 3.0 g of the pigment-containing polymer gel particles in a dry state obtained by the same method as in Example 3 was used.
What was swollen with 200 g of pure water having a pH of 7 was used as a polymer gel dispersion solution. The amount of water absorbed by the polymer gel particles at this time was about 200 g / g, which was exactly the same as the amount of swelling during color development. A substrate subjected to silane coupling treatment in the same manner as in Example 2 is immersed in this polymer gel dispersion solution,
Immobilization was carried out by reacting at 60 ° C. for 10 hours.

The polymer gel particles on the substrate are swollen in pure water at pH 7, but are immobilized on the substrate by the swelling amount at the time of color development. Due to steric factors, flow in the swelling solution, and the like, gaps were formed between the polymer gels, and the gels were not fixed at a high occupancy. An image of this substrate observed with a microscope at a magnification of 550 was processed on a PC in the same manner as in Example 1. As a result, the polymer gel occupancy on the substrate was 60% or less.
This substrate showed color unevenness even when visually observed, and did not show a favorable color development state. This is because the polymer gel particles were immobilized at the swelling amount at the time of color development, so that many gaps were formed between the gels.

[0093]

According to the present invention, an optical element which uses a stimulus-responsive polymer gel which repeats swelling and shrinkage, has excellent color-forming properties or light-scattering properties upon swelling, and can obtain a good contrast ratio, and a method for producing the same. Can be provided. Further, according to the present invention, uneven distribution (density unevenness) of the swollen gel in a light control / colored state due to repeated swelling / shrinking.
It is possible to provide an optical element and a method for manufacturing the same, which can prevent an increase in the optical speed and can also solve the problem of a reduction in response speed.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of the optical element of the present invention.

FIG. 2 is a schematic plan view showing an example of the optical element of the present invention.

[Explanation of symbols]

 2 Transparent substrate 4 Transparent substrate 6 Stimuli-responsive polymer gel 8 Absorbable liquid 10 Stimulation means 12 Stimulation means 14 Spacer 16 Sealing material

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) G02B 5/02 G02B 5/02 B (72) Inventor Koga Komura 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. In-house (72) Inventor Takashi Uematsu 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Atsushi Atsushi Kawahara 1600 Takematsu, Minami-Ashigara-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd.F-term (reference) 2H042 AA15 AA26 BA02 BA11 BA13 BA15 BA20

Claims (3)

[Claims] 1. At least a pair of substrates, a stimulus-responsive polymer gel, and a liquid that can be absorbed in the stimulus-responsive polymer gel, and contribute to light control during color development or light scattering. The ratio of the area of the orthographic projection of all the stimuli-responsive polymer gels immobilized as a single particle layer on the substrate on the substrate to the effective area of the substrate is 70% or more. Optical element. 2. An optical element comprising at least a step of immobilizing a stimuli-responsive polymer gel on a substrate and a step of filling a liquid absorbable in the stimuli-responsive polymer gel between the substrates. A method for producing an optical element, wherein the stimulus-responsive polymer gel is immobilized on the substrate with an amount of swelling smaller than the amount of swelling during coloring or light scattering. 3. The optical element according to claim 2, wherein the stimulus-responsive polymer gel is immobilized on the substrate with a swelling amount smaller by 5 to 30% by weight than a swelling amount at the time of coloring or light scattering. Production method.