JPH09297325A - Optical device and electrolytic solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stable device by adding an additive such as 1,4- benzodioxane to a silver salt-contg. RED soln. and forming a reversible system in which silver is deposited on an electrode or dissolved by controlling the driving of opposite electrodes. SOLUTION: A silver salt soln. 1 is sealed in the space between opposite electrodes 2, 3 and silver is deposited or dissolved by controlling the driving of the electrodes 2, 3. The Soln. 1 contains at least one kind of additive selected from among 1,4-benzodioxane, 2-hydroxymethyl-1,4-benzodioxane, 1,2- methylenedioxabenzene, quinoxaline, phthalide, salicylmethyl ester, 4- hydroxycoumarin, 7-dimethylamino-4-methylcoumarin, coumaric acid, coumarin, 6-methylcoumarin, 3,4-dihydro-2H-pyrane and D-glucono-1,5-lactone.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device (for example, a display device for displaying numbers or characters or an XY matrix display, and a visible light region (wavelength: 400 to 70).
(0 nm), a filter whose light transmittance can be controlled), and an electrolytic solution used in this device.

[0002]

2. Description of the Related Art Conventionally, an electrochromic material (hereinafter, sometimes referred to as an EC material) has been used for a voltage-driven display device, for example, a digital timepiece for displaying time.

An electrochromic display element (hereinafter referred to as E
Sometimes referred to as a CD. ) Is a non-light-emitting type display device, which has an advantage that the display is based on reflected light or transmitted light, so that there is little fatigue even after long-time observation, and the driving voltage is relatively low, and It has advantages such as low power. For example, as disclosed in JP-A-59-24879, a liquid type ECD using an organic molecular viologen molecule derivative which forms a reversibly colored or decolored state as an EC material is known. I have.

With the development of precision optical equipment, there is a need for a fine and low power consumption type light quantity adjusting device which replaces the conventional variable ND filter.
It is necessary to consider whether the CD or its peripheral technology can be adapted to it.

However, when an EC material such as a viologen molecule derivative is used for the ECD, there are problems in the actually required response speed and the degree of shielding at that time, and it has been difficult to put it to practical use.

In view of this, instead of ECD, attention has been paid to a reflection-type light control element utilizing precipitation / dissolution of a metal salt, and an electrochemical light control element utilizing precipitation / dissolution of silver has been developed. .

However, in such an electrochemical light control device, the response speed and the degree of shielding can be obtained as desired, but the electrolyte solution used is salicylic acid, 5-sulfosalicylic acid, salicylaldoxime. Since it contains an additive that dissolves the constituent elements of the transparent electrode like a chelating agent under high temperature storage, deterioration of the transparent electrode easily occurs,
Device life tends to be short.

In particular, although such an additive originally functions as a complexing agent or the like, ITO (Indium Tin Oxi)
de) Since the electrode is dissolved as a chelating agent, there is a problem that the ITO electrode is dissolved under high temperature storage that promotes the reaction. As a result, the operation of the device becomes unstable under high temperature storage.

[0009]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide an electrolytic solution required for a device, which solution has a visible light range (400 to 70
An optical device that does not have absorption at (0 nm), and that uses a silver complex salt capable of almost uniformly shielding in the visible light region during coloring as an electrochemical light control element material, and that is stable in operation even at high temperatures, and The purpose is to provide an electrolytic solution used for.

[0010]

DISCLOSURE OF THE INVENTION The present inventor reversibly deposits silver from a silver complex salt on an electrode in a non-aqueous system or dissolves it from the electrode (hereinafter, sometimes referred to as “precipitation, dissolution”). By constructing a dimming device using an electrochemical material, it is possible to drive with low power consumption, control the light transmittance in the visible light region, have good spectral characteristics, and The present invention has reached the present invention by finding a stable optical device and electrolytic solution under high temperature storage, and further under high temperature and low temperature environments.

That is, the present invention is arranged such that a solution of a silver salt is arranged between opposed electrodes, and silver is deposited or dissolved by controlling the drive of these electrodes.
-Benzodioxane, 2-hydroxymethyl-1,4-
Benzodioxane, 1,2-methylenedioxybenzene, quinoxaline, phthalide, salicylmethyl ester, 4-hydroxycoumarin, 7-dimethylamino-4
-Methylcoumarin, coumarinic acid, coumarin, 6-methylcoumarin, 3,4-dihydro-2H-pyran, dehydroacetic acid, thiouracil, thiourea, 1-allyl-2-thiourea, 2-mercaptothiazoline, mercaptobenzimidazole, Aminobenzothiazole, phthalimide,
Phthalic anhydride, phthalic acid, succinic acid, salicylic acid, salicylaldehyde, salicylamide, salicylanilide,
Glycolic acid, tartaric acid, oxalic acid, dimethylamine borane, trimethylamine borane and D-glucono-1,5
An optical device to which at least one additive selected from the group consisting of lactones (hereinafter referred to as the additive of the present invention) is added, and an electrolytic solution comprising the solution containing the additive. It is related.

The electrolytes obtained so far include ITO.
Since an additive such as salicylic acid that dissolves the electrode like a chelating agent is included, there is a problem that the ITO electrode dissolves under high temperature storage that accelerates the reaction. According to the present invention, such a chelating agent is removed from the electrolyte and replaced by adding an additive of the present invention such as 1,4-benzodioxane as described above, or when salicylic acid is used as an additive. By using a solvent such as dimethyl sulfoxide together, it is possible to supply a device which does not deteriorate the electrode and is stable even under high temperature storage.

That is, it is extremely important that the additive of the present invention does not dissolve the electrode and has a function of reversibly promoting precipitation or dissolution of silver. And, in order to exert its effect effectively, this additive is 0.1-200 g /
It is preferable to add L to the electrolytic solution.

Conventionally, for depositing silver from a silver complex salt, a cyan-based solution used as a plating bath is well known. However, the cyan-based solution is used for securing a safe working environment and for treating the waste solution thereof. There's a problem. Therefore, the present inventor paid attention to a non-cyanide silver salt and studied the same.

That is, the reversible system was obtained by adding the above-mentioned additives and the like from the electrolytic solutions of various silver complex salts. The material used for this system is RED ( R eversible E
called lectro D eposition) material, R is dissolved in a solvent
Prepared in ED solution.

As the RED solution (electrolyte solution), a solution using silver iodide as a silver halide, ascorbic acid as a reducing agent for improving reversibility, and dimethyl sulfoxide (DMSO) as a nonaqueous solvent has been studied so far. It was However, in the case of silver iodide system, the image during shielding is caused by the deterioration of the electrolytic solution due to the generation of iodine during dissolution of silver and the spectral characteristics of the deposited silver film that does not have uniform absorption in the visible light range. Deterioration of information may be a problem.

The cause of this is that the standard redox potential of iodine is lower than that of bromine or chlorine, as shown below. (Based on hydrogen)

Embedded image

Therefore, in the present invention, among AgF, AgCl, AgBr, AgI and the like which can be used as a silver salt,
It is desirable to use silver chloride having a high standard redox potential. That is, when silver chloride is used, it is possible to reduce the coloring side reaction gas generated as described above when silver is dissolved, and obtain a system in which the deposited silver film has uniform absorption in the visible light region. As a result, it is possible to realize a system in which the deposited silver film has good spectral characteristics, and it is possible to effectively avoid deterioration of optical information due to color unevenness during shielding.

Not to mention the RED solution according to the present invention, when a solution is prepared, the solution does not have absorption in the visible light range (wavelength: 400 to 700 nm), and at the time of coloring, almost uniform shielding is achieved in the visible light range. Possible silver halide such as silver chloride (complex salt)
Is preferably used as the material. In addition, this silver halide (complex salt) is rich in reversibility of precipitation-dissolution under drive control.

As described above, the present invention is suitable for a non-emission type visible light region with low power consumption by using a reversible system in which silver is deposited and dissolved on an electrode from a silver salt consisting of silver chloride. An optical device, such as a display device or an optical filter, can be provided.

The optical device of the present invention is constructed by filling an electrolytic solution in which a silver salt is dissolved in a solvent between the opposing electrodes, at least one of which serves as an electrode for depositing or dissolving silver, in contact with these electrodes. You can

Then, a solution in which silver halide is dissolved in water or a non-aqueous solvent, particularly a non-aqueous solution, is disposed, and it is desirable that the solution is colored or decolored by the precipitation or dissolution of silver.

In this case, the silver salt concentration is 0.03 to 2.0 mol /
It is desirable to use a RED liquid having an L content of 0.05 to 2.0 mol / L.

Then, at least one additive selected from the group consisting of a brightening agent and a reducing agent is preferably added to the solution.

For example, the group consisting of thiourea, 1-allyl-2-thiourea, mercaptobenzimidazole, coumarin, ascorbic acid, dimethylamineborane (DMAB), trimethylamineborane (TMAB), tartaric acid, oxalic acid and gluconolactone. At least one selected from the above may be used.

As the RED liquid usable in the present invention, it is desirable to dissolve the silver salt and use it in combination with a reducing agent to prepare a system having a high reversibility. However, such R
Ascorbic acid has been used as a reducing agent as an ED solution, while dimethyl sulfoxide (DMS) has been used as a solvent.
It has been studied to use only a non-aqueous solvent consisting of O), but such a RED solution has a problem in low-temperature characteristics because DMSO itself has a freezing point at 18 ° C., for example, freezing during use in a cold region. It is easy to occur. For this reason, there are limitations on the solvents that can be used.

Therefore, the present inventor, especially in a reversible system in which silver is deposited and dissolved from a silver complex salt on a transparent electrode in a non-aqueous system, prevents deterioration of low temperature characteristics and has a low freezing point that can withstand use at low temperature. Using a solvent, a reducing agent applicable to this was investigated.

From these results, as a reducing agent applicable to a solvent having a low freezing point, which has never been studied,
Any of the reducing agents such as DMAB and TMAB described above can be sufficiently used even if a solvent having a low freezing point is used for improving low-temperature characteristics, and are more easily dissolved in such a solvent than ascorbic acid described above. is there. That is, since it becomes an electrolytic solution that solidifies at a lower temperature than the DMSO-based electrolytic solution, this electrolytic solution does not freeze even in use in cold regions.

In this case, the reducing agent is preferably added in the range of 1/150 times to 1 times the silver salt concentration.

As the solvent having a low freezing point, dimethylformamide (DMF) and diethylformamide (D
EF), N, N-dimethylacetamide (DMAA),
N-methylpropionamide (MPA), N-methylpyrrolidone (MP), propylene carbonate (P
C), acetonitrile (AN), 2-methoxyethanol (MEOH), 2-ethoxyethanol (EEO)
H), dimethyl sulfoxide (DMSO), dioxolane (DOL), ethyl acetate (EA), tetrahydrofuran (THF), methyl tetrahydrofuran (MeTH)
A solvent (non-aqueous solvent) consisting of at least one selected from the group consisting of F), dimethoxyethane (DME) and γ-butyrolactone (GBL) is desirable.

All of these non-aqueous solvents have a lower freezing point than DMSO (especially DMF, DEF, MEOH, E).
(EOH is as low as 70 ° C or higher), and the RED solution prepared by dissolving silver salt, especially silver chloride, has excellent low temperature characteristics.
For example, it will be sufficiently durable for use in cold regions.

As described above, the temperature characteristic has been a problem so far when a solvent of DMSO alone is used. Therefore, in the present invention, so that DMSO can also be used,
By selecting a solvent that is compatible with DMSO (for example, acetonitrile) and using both of them as a mixed solvent, a solvent that does not coagulate even at a low temperature can be obtained, and the temperature characteristic problem can be solved. Others, DOL, EA, THF, M
Similar to the above, eTHF, DME, and GBL can be used as a mixed solvent.

Further, in order to increase the conductivity of the RED solution and dissolve silver halide (particularly silver chloride), a supporting salt (supporting electrolyte) capable of supplying the same or different halogen element is added to add silver halide. Complex silver is desirable. Examples thereof include sodium halide, potassium halide, calcium halide, and quaternary ammonium halide salt.

Such a supporting salt is 1/2 of silver halide.
It is preferable that the concentration is added in the range of double concentration to 5-fold concentration.

The lifetime can be extended by reducing the overvoltage of silver precipitation / dissolution, which is an important factor in the lifetime of the device. Although the overvoltage on the deposition side cannot be controlled, the dissolution overvoltage of the deposited silver film can be determined by co-depositing with a dissimilar metal such as a copper salt (eg copper halide) or by mixing the silver ligand of the complex. Has been successfully reduced.

Further, since the device is arranged in the optical system, it is not desirable that the electrolyte has absorption (coloring) in the visible light region. Usually, when copper halide is dissolved in an organic solvent, it has absorption in the visible light region. Therefore, by using a dissolved copper salt and a transparent material such as triethanolamine to reduce the state of copper in the solvent so that Cu ²⁺ → Cu ⁺ , the electrolytic solution in the visible light region is reduced. Was able to avoid light absorption.

As such a clarifying agent, triethanolamine, iminodiacetic acid, trans-1,2-cyclohexanediamine-tetraacetic acid, nitrilotriacetic acid, galactitol, triethanolamine borate, N, N,
N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, ethylenediamine-N, N, N ′,
At least one selected from N′-tetraazetic acid, salicylic acid, 2-mercaptobenzimidazole, 1-allyl-2-thiourea, thiouracil, dimethylamineborane, ascorbic acid, and dimethylthioformamide can be used.

Further, a transparent electrode (particularly, an ITO electrode: obtained by doping indium oxide with tin) serving as a working electrode for depositing or dissolving silver is chemically or physically modified to form a transparent electrode. The deposition potential of silver on the electrode can be lowered, silver can be easily deposited and dissolved, and the transparent electrode and the solution itself can be electrically damaged.

As a chemical modification method in this case, it is preferable to perform a surface treatment (chemical plating) of the ITO electrode with palladium or the like by a two-liquid treatment method of a tin solution and a palladium solution. That is, as the surface activation treatment of the ITO electrode with palladium, the activity on the surface of the ITO electrode is enhanced by depositing palladium nuclei on the ITO single substrate.

In this case, as the tin solution, 0.10 to 1.0 g of tin chloride (SnCl ₂ ) is added to 0.010 to 0.10% HCl.
What was dissolved in 1 L, the palladium solution, palladium chloride (PdCl ₂ ) 0.10 ~ 1.0 g 0.010 ~ 0.10%
A solution dissolved in 1 L of HCl can be used.

As a physical modification method, a method in which a metal or the like which is nobler than silver is deposited on the ITO electrode can be adopted.

In the optical device of the present invention, the solution has no absorption in the visible light region in the decolored state, and the coloring and decoloring substrate electrodes are in the visible light region in order to operate as an optical device. It is desirable to use an ITO electrode that does not absorb light.

When the coloring and decoloring states are repeated using the RED solution, the solution system cannot be agitated due to the small size of the device. Therefore, it is preferable to drive by current control which makes it easy to quantify the electrochemical deposition and dissolution of silver.

As a driving method of coloring / decoloring by such current control, in order to increase the coloring / decoloring speed (the rate of silver precipitation and dissolution), a current that changes in a rectangular shape from a high current value to a low current value is used. It is preferable to use the driving method by Alternatively, in order to reduce damage to the substrate due to repeated deposition and dissolution of silver, a driving method using a current that changes from a low current value to a high current value in a rectangular shape may be used. When the constant current drive is used, it is desirable to control the potential generated by the by-product using a limiter or the like (for maintaining the balance of the electrolyte of the system).

The present invention provides a method of displaying numbers or characters, or X-
The present invention can be widely applied to display devices capable of Y-matrix display and the like, and optical devices such as optical filters capable of controlling light transmittance in the visible light range (wavelength: 400 to 700 nm).

The present invention also provides, as an electrolytic solution usable in such an optical device, an electrolytic solution composed of a solution prepared by dissolving the above-described silver salt, additives and the like in a solvent.

This electrolytic solution comprises a solution in which a silver salt such as silver chloride is dissolved in water or a non-aqueous solvent at a concentration of preferably 0.03 to 2.0 mol / L, and is colored or decolored by the precipitation or dissolution of silver. The additives of the present invention similar to those described above can be added, and in some cases, a predetermined amount of a brightener, a reducing agent, a supporting salt and a solvent can be contained.

[0048]

Embodiments of the present invention will be described below.

First, referring to FIGS. 15 and 16, an optical device such as a display element (or an optical filter) according to an embodiment of the present invention.
An example of 10 is schematically shown.

According to the optical device 10 of this embodiment, a pair of transparent substrates (eg, glass plates) 4 and 5 that constitute a cell are arranged as a display window at regular intervals, and the inner surface of each substrate is
Working electrodes (for example, ITO electrodes) 2 and 3 at least one of which serves as a coloring electrode or an erasing electrode are provided facing each other. Although these working electrodes are actually formed in a pattern according to the purpose, they are shown schematically in the drawings.

The counter electrode 6 is provided on the entire periphery of the substrates 4 and 5 also as a spacer, and for example, a silver plate is used. Although not shown, for example, a silver wire is provided as a reference electrode.

Then, a RED liquid prepared by dissolving additives such as silver chloride (complex salt) and 1,4-benzodioxane as a RED material in a non-aqueous solvent between the counter electrodes 2-3 is in contact with these electrodes. 1 is enclosed. At least one of the counter electrodes 2 and 3 is used as a cathode, and a DC drive voltage is applied between the counter electrode 6 and the counter electrode 6 only for a predetermined time, whereby a silver (complex) salt is formed.

Embedded image An oxidation-reduction reaction is caused on the cathode side, and the precipitate is changed from a transparent state to a colored state by the Ag deposit.

By thus depositing Ag on the electrode, a specific color (for example, a reflection color) due to the Ag deposit can be observed from the display window, and the filter material is obtained. Then, the filter action due to this coloring, that is, the transmittance of visible light (or the shade of coloring) changes with the magnitude of the voltage or the application time thereof, and by controlling this, it functions as a variable transmittance display element or filter. be able to.

The optical device 10 may have the counter electrodes 2 and 3 on almost the entire surface in the cell, but in practice, it can be constructed as shown in FIGS. 17 and 18, for example.

That is, the IT provided on the transparent substrates 4 and 5
The O counter electrode is divided into a center part 2a, 3a and ring-shaped electrodes 2b, 3b, 2c, 3c, 2d, 3d, 2e, 3e arranged concentrically at a small distance around the center part 2a, 3a. ing. Silver counter electrodes 6A and 6B for potential compensation are provided around the outermost counter electrodes 2e and 3e.

Each of these electrodes 2a, 3a, 2b, 3b,
2c, 3c, 2d, 3d, 2e, 3e, 6A, 6B are driving power supplies 8A, 8B, 8C, 8D, 8E, 8 respectively.
Wirings 9A, 9B, 9C, 9 made of fine chrome wires etc.
D, 9E, and 9F.

The transparent substrate 4-5 is arranged at a predetermined interval by the spacer 7 (this also serves as the counter electrode 6 in FIG. 13), and the RED liquid 1 is enclosed in the interval.

Since the redox reaction (that is, the concentration) of the RED liquid 1 is controlled according to the magnitude of the applied voltage, the above-mentioned divided electrodes 2a-3a, 2b-3b,
2c-3c, 2d-3d, the voltage applied to 2e-3e (respectively _{V 1, V 2, V 3} , and V _4, V _5.) By the silver from RED solution on the cathode of the divided electrodes It is possible to change the amount of precipitation of (the counter electrode 6A-
The voltage V ₆ for potential compensation is also applied to 6B).

Therefore, if all the voltages are made equal (V ₁ = V ₂ = V ₃ = V ₄ = V ₅ ), the RED liquid 1 can be colored uniformly over the entire area, and , The degree of density can be changed uniformly.

If the voltage applied to each electrode is made different, for example, V ₁ <V ₂ <V ₃ <V ₄ <V ₅ , the coloring density becomes higher from the center to the periphery (in other words, If this is the case, the transmittance will be small). This is CCD for TV camera etc.
(Charge-coupled device)
It is possible to sufficiently cope with the improvement of the integration degree of CD. If the applied voltage is set in the reverse order to the above, the transmittance increases from the central portion to the periphery.

As described above, the shading or gradation can be controlled in various patterns by the voltage applied to the divided electrodes.
It becomes useful as an optical filter, and the range of its use condition is widened.

As described above, according to this embodiment, based on an idea completely different from the conventional EC material, the RED material made of silver chloride is used as the filter material for adjusting the light amount of the optical device. By controlling the drive of the counter electrode (particularly applied voltage), the shade of the RED material at the time of coloring can be changed, and by utilizing this feature, it is possible to add gradation to the display element or the optical filter. Therefore, by using the RED material, it is possible to provide a filter that is finer and requires less power consumption, and has a capacity exceeding that of a conventional variable ND filter that has been mechanically operated as a light amount adjusting device.

Further, since the RED solution in which silver chloride is dissolved in a non-aqueous solvent (for example, DMF) is used as the RED material, the freezing point of the non-aqueous solvent is sufficiently low and the low temperature characteristics are excellent. This non-aqueous solvent sufficiently dissolves the reducing agent (for example, DMAB) added to the RED material together with silver chloride.

Further, since the RED solution does not contain a chelating agent, but an additive such as 1,4-benzodioxane is added, the ITO transparent electrode does not dissolve even at high temperature storage.

Next, this embodiment will be described in more detail with reference to specific examples. In the following specific examples, the optical device configured as in the examples shown in FIGS. 15 and 16 was used.

<Cyclic voltammetry (CV)
Characteristic Evaluation Using Measurement Method> Example 1 (Electrolyte with Salicyl Methyl Ester Added) Silver chloride was used in order to study a system of reversible silver deposition and dissolution. In this example, the purpose was to investigate the precipitation and dissolution properties of silver.

Acetonitrile (AN) was used as the solvent. The silver chloride concentration was set to 0.5 mol / L, and for the purpose of dissolving it and increasing the conductivity, a quaternary ammonium salt [here, tetrabutylammonium chloride (Tetra-n-
butyl ammonium chloride) (TBAC)] 0.75 mol /
L was dissolved. As an additive of the present invention, 1.0 g / L of salicylmethyl ester was dissolved to prepare a RED solution (electrolytic solution), which was placed in the cell of the optical device.

The potential sweep (cyclic voltammetry: CV) method is used for the measurement, and the potential of silver is -1.2 V.
Swept between + 2.0V. The starting point of the sweep was at the same potential as the silver potential, and the measurement was performed from the reducing side at a sweep rate of 100 mV / sec.
All sweeping was performed from the reduction side, and the precipitated silver film was dissolved on the oxidation side to complete one cycle. A circular ITO electrode having a diameter of 7 mm was used as a working electrode.

As is clear from the CV curve shown in FIG.
The electrolyte according to this example has a large dissolution peak on the oxidation side,
It can be seen that the system is reversible.

Example 2 (Electrolytic solution containing 1,2-methylenedioxybenzene) A RED solution was prepared in the same manner as in Example 1 except that 1,2-methylenedioxybenzene was added instead of salicylmethyl ester. Was prepared, and CV measurement was performed on the optical device filled with the above.

As is clear from the CV curve shown in FIG.
The electrolyte according to this example has a large dissolution peak on the oxidation side,
It can be seen that the system is reversible.

Example 3 (Electrolytic solution containing 1,4-benzodioxane) A RED solution was prepared in the same manner as in Example 1 except that 1,4-benzodioxane was added instead of salicylmethyl ester. CV measurement was performed on the optical device filled with this.

As is clear from the CV curve shown in FIG.
The electrolyte according to this example has a large dissolution peak on the oxidation side,
It can be seen that the system is reversible.

Example 4 (Electrolyte solution added with 2-hydroxymethyl-1,4-benzodioxane) In Example 1 described above, except that 2-hydroxymethyl-1,4-benzodioxane was added instead of salicylmethyl ester. In the same manner, a RED solution was prepared, and CV measurement was performed on the optical device filled with the RED solution.

As is clear from the CV curve shown in FIG.
The electrolyte according to this example has a large dissolution peak on the oxidation side,
It can be seen that the system is reversible.

Example 5 (Electrolyte solution containing quinoxaline) A RED solution was prepared in the same manner as in Example 1 except that quinoxaline was added instead of salicylmethyl ester, and CV measurement was performed on an optical device filled with the RED solution. went.

As is clear from the CV curve shown in FIG.
The electrolyte according to this example has a large dissolution peak on the oxidation side,
It can be seen that the system is reversible.

Example 6 (Electrolyte solution containing 2,3-dihydro-4H-pyran) The same procedure as in Example 1 except that 2,3-dihydro-4H-pyran was added instead of salicylmethyl ester. A RED solution was prepared, and CV measurement was performed on an optical device filled with the RED solution.

As is clear from the CV curve shown in FIG.
The electrolyte according to this example has a large dissolution peak on the oxidation side,
It can be seen that the system is reversible.

Example 7 (Electrolyte solution containing phthalide) A RED solution was prepared in the same manner as in Example 1 except that phthalide was added instead of salicylmethyl ester, and CV measurement was performed on an optical device filled with the RED solution. went.

As is clear from the CV curve shown in FIG.
The electrolyte according to this example has a large dissolution peak on the oxidation side,
It can be seen that the system is reversible.

<Evaluation of Spectral Characteristics in CV Measurement> Example 8 (Electrolyte Solution of Comparative Example in which Salicylic Acid and Coumarin were Added) In Example 1, salicylic acid (1 g / L) and coumarin (1 g / L) were used instead of salicylmethyl ester. A RED solution was prepared in the same manner except that each of the above was added, and an optical device filled with the RED solution was examined for changes in transmittance during deposition and dissolution of silver.

The change in transmittance was traced under the following potential conditions. Here, an ITO electrode was used as the working electrode, a silver wire was used as the reference electrode, and a silver plate was used as the counter electrode.

FIGS. 8 and 9 show changes in the spectral characteristics measured using the RED solution (electrolyte solution) described above. FIG. 8 is a spectral characteristic showing a decrease in transmittance when the silver film is deposited, and FIG. 9 is a spectral characteristic showing recovery of the transmittance when the silver film is dissolved.

A potential sweep (cyclic voltammetry: CV) method is used for the measurement, and the potential of silver is -1000.
Swept between mV and +1500 mV. The starting point of the sweep was at the same potential as the silver potential, and the measurement was performed from the reducing side at a sweep rate of 100 mV / sec.

From the results shown in FIGS. 8 and 9, it was possible to obtain a change in transmittance by using the electrolytic solution of this example. The spectral characteristics of the deposited silver film in this system show that it has a uniform absorption in the visible light region, and that the transmittance rises and falls in the precipitation and dissolution as well. Is shown.

However, it has been found that the above salicylic acid has a chelating ability and therefore reacts with the constituent elements of the transparent electrode and, as a result, dissolves the electrode. Therefore, it was found that it was insufficient for deviceization.

Example 9 (Electrolyte solution containing 1,4-benzodioxane) In Example 8, 1,4 was used instead of salicylic acid and coumarin.
-Spectral characteristics were similarly measured for the RED liquid to which benzodioxane was added (see Example 3).

FIG. 10 shows the spectral characteristics when the silver film is deposited, and FIG. 11 shows the spectral characteristics when the silver film is dissolved. According to this, by using the electrolytic solution according to this example, it was possible to obtain a sufficient change in the transmittance without using the reducing agent. The spectral characteristics of the deposited silver film in this system show uniform absorption in the visible light region, and it can be seen that the transmittance similarly rises and falls during precipitation and dissolution, and it has a light shielding ability in the visible light region. It indicates that

It was confirmed that this electrolytic solution did not contain an electrolyte that reacts with the electrode, and that the electrode did not dissolve even under high temperature storage.

Example 10 (Cryogenic Storage Test of Non-Aqueous Solvent) The freezing points of various non-aqueous solvents are summarized in Table 1 below.

Table 1 Solvent Freezing Point (Pure Solvent) ──────────────────── Solvent Freezing Point (℃) ────────────── ─────── DMF-60.4 ──────────────────── DEF-78.0 ────────────── ─────── DMAA-20.0 ──────────────────── MPA -30.9 ────────────── ─────── N-MP-24.4 ──────────────────── MEOH-85.1 ──────────── ───────── EEOH-60.4 ──────────────────── PC-49.0 ──────────── ───────── AN-45.7 ──────────────────── DM SO 18.0 ─────────────────────

Then, a solvent low temperature storage test was conducted using each solvent, and the results shown in Table 2 below were obtained.

Table 2 Results of low temperature solvent storage test (stored at -40 ° C for 24 hours) AgCl: 500 mM TBAC: 750 mM salicylmethyl ester: 1 g ────────────────────── Solvent form ──────────────────── DMF liquid ──────────────────── DEF liquid ── ────────────────── DMAA Partial solidification ──────────────────── MPA liquid ────── ────────────── N-MP partial solidification ──────────────────── MEOH liquid ───────── ──────────── EEOH liquid ──────────────────── PC liquid ────────────── ────── AN liquid ────────── ────────── DMSO Coagulation ────────────────────

Thus, the non-aqueous solvent other than DMSO is-
Even if it is stored at 40 ° C, it does not solidify and can be practically used in the liquid state, but in the case of DMSO, it solidifies (freezes) completely and becomes unusable.

Example 11 (Mixed solvent test) In this example, DMSO: AN = 1: 1 consisting of dimethyl sulfoxide (DMSO) and acetonitrile (AN).
An electrolytic solution was prepared using the system mixed solvent, and the spectral characteristics in the visible light region were measured in the same manner as described above. As an electrolytic solution, AgBr 500 mM and tetra-n-butylammonium bromide 750 mM were dissolved in the above mixed solvent, and succinic acid was used as an additive. The results are shown in FIGS. 12 and 13.

Driving is performed by potential sweep, 100 mV / sec
And FIG. 12 shows the change in transmittance when shielded (when silver was deposited), and FIG. 13 shows the change in transmittance when made transparent (when silver was dissolved).

From the results shown in FIGS. 12 and 13, it was possible to obtain a change in transmittance by using the electrolytic solution of this example. The spectral characteristics of the deposited silver film in this system show that it has a uniform absorption in the visible light region, and that the transmittance rises and falls in the precipitation and dissolution as well. Is shown.

In Example 10 above, dimethyl sulfoxide (DMSO) was found to have high reversibility of silver precipitation and dissolution, but was inferior in low temperature characteristics, but in this example, DMSO inferior in such temperature characteristics was found. Even when used, it was possible to maintain a liquid state even at −40 ° C. by using it as a mixed solvent with acetonitrile (AN) that does not coagulate at low temperature. As a result, the electrolytic solution did not freeze even in use in cold regions, and the range of usable additives increased.

Example 12 (Solubility of Salicylic Acid) As shown in Example 8 above, salicylic acid has a chelating ability depending on the solvent used, and when dissociated in the solvent, it acts as a chelate on the ITO electrode to form an ITO electrode structure. May elute element. This is affected by the dissociation constants of various acids and bases in organic solvents.

Regarding this, using salicylic acid as an example, the dissociation constants in various solvents are summarized in Table 3 below.

Table 3 ─────────────────────────────────── Solvent AN PC DMS DMF NMP MEOH Water ─ ──────────────────────────────────Dissociation constant of salicylic acid 16.8 15.2 6.7 8.2 8.6 7.9 2.97 ───── ────────────────────────────── However, AN: acetonitrile PC: propylene carbonate DMSO: dimethylsulfoxide DMF: dimethylformamide NMP: n -Methylpyrrolidone MEOH: 2-methoxyethanol

As described above, salicylic acid has a high dissociation constant in AN and PC, but DMSO, DMF, NMP, M
It can be seen that when EOH or water is used as the main solvent, the dissociation constant becomes extremely small and almost no dissociation occurs, so that it does not function as a chelate.

On the other hand, salicylic acid was dissolved in AN to prepare an electrolytic solution as in Example 8 above, and the etching rate when the ITO electrode was dipped was measured.
The result shown in FIG. According to this, it is understood that the dissolution of the ITO electrode increases with time and the electric resistance thereof remarkably increases.

Although the embodiments of the present invention have been described above, the above embodiments can be further modified based on the technical idea of the present invention.

For example, the types of RED materials and RE
The liquid D component, especially the combination and concentration of the additives of the present invention may be variously changed.

Further, the materials including the structure including the ITO electrode pattern, the components, and the driving method are not limited to those described above. For example, the electrode pattern as shown in FIG. 17 may be variously changed into a stripe shape, a lattice shape, or the like, or different RED liquid cells may be divided and arranged in parallel for each divided electrode. In this case, RE
The D solution and the conventional EC solution can be combined.

The optical device according to the present invention can be combined with other known filter materials (for example, organic electrochromic material, liquid crystal, electroluminescent material). Further, the optical device according to the present invention has a C
It can be widely applied to various optical systems such as an optical diaphragm of a CD, and also to a light amount adjustment of an electrophotographic copying machine or an optical communication device.

[0109]

The present invention, as described above, is a conventional EC.
RE containing silver salt based on an idea completely different from the material
An additive such as 1,4-benzodioxane is added to the liquid D to form a reversible system in which silver is deposited and dissolved on the electrode by drive control of the counter electrode (particularly applied voltage). Therefore, it is possible to provide an optical device suitable for the non-emission type visible light region with low power consumption by using the RED material, and it is stable even at high temperature storage because it does not contain a chelating agent that dissolves the electrode. You can get the device.

[Brief description of drawings]

FIG. 1 is a CV curve diagram of an optical device according to the present invention.

FIG. 2 is a CV curve diagram of another optical device according to the present invention.

FIG. 3 is a CV curve diagram of another optical device according to the present invention.

FIG. 4 is a CV curve diagram of another optical device according to the present invention.

FIG. 5 is a CV curve diagram of another optical device according to the present invention.

FIG. 6 is a CV curve diagram of another optical device according to the present invention.

FIG. 7 is a CV curve diagram of another optical device according to the present invention.

FIG. 8 is a spectrum diagram showing a change in transmittance depending on an applied voltage when an optical device according to a comparative example is colored.

FIG. 9 is a spectrum diagram showing a change in transmittance depending on an applied voltage when an optical device according to a comparative example is decolored.

FIG. 10 is a spectrum diagram showing a change in transmittance according to an applied voltage when coloring the optical device according to the present invention.

FIG. 11 is a spectrum diagram showing a change in transmittance depending on an applied voltage when the optical device according to the present invention is decolored.

FIG. 12 is a spectrum diagram showing a change in transmittance according to an applied voltage when coloring another optical device according to the present invention.

FIG. 13 is a spectrum diagram showing a change in transmittance according to an applied voltage at the time of color erasing of still another optical device according to the present invention.

FIG. 14 is a graph showing an electrode etching rate of an optical device according to a comparative example.

FIG. 15 is a schematic sectional view of an optical device according to the present invention.

FIG. 16 is a conceptual diagram of the optical device.

FIG. 17 is an ITO electrode pattern diagram of a specific example of the optical device.

FIG. 18 is a schematic cross-sectional view of the optical device.

[Explanation of symbols]

1: RED solution (silver salt-containing solution), 2, 2a to 2e, 3, 3
a to 3e: ITO electrode 4, 5, display window (transparent substrate), 6, 6A, 6B: counter electrode,
7 spacer, 8A to 8F power supply, 10 optical device

Claims (26)

[Claims] 1. A solution of a silver salt is arranged between opposed electrodes, and is configured to drive or control these electrodes to cause precipitation or dissolution of silver. The solution contains 1,4-benzodioxane, 2- Hydroxymethyl-
1,4-benzodioxane, 1,2-methylenedioxybenzene, quinoxaline, phthalide, salicylmethyl ester, 4-hydroxycoumarin, 7-dimethylamino-4-methylcoumarin, coumarinic acid, coumarin, 6-methylcoumarin, 3 , 4-dihydro-2H-pyran, dehydroacetic acid, thiouracil, thiourea, 1-allyl-2-
Thiourea, 2-mercaptothiazoline, mercaptobenzimidazole, aminobenzothiazole, phthalimide, phthalic anhydride, phthalic acid, succinic acid, salicylic acid,
Salicylaldehyde, salicylamide, salicylanilide, glycolic acid, tartaric acid, oxalic acid, dimethylamine borane, trimethylamine borane and D-glucono-
At least one selected from the group consisting of 1,5-lactones
Optical device to which seed additives have been added. 2. The optical device according to claim 1, wherein the additive does not dissolve the electrode and has a function of promoting precipitation or dissolution of silver. 3. The optical device according to claim 1, wherein the additive amount is 0.1 to 200 g / L. 4. An electrolytic solution in which the silver salt is dissolved in a solvent is filled between the opposing electrodes, at least one of which serves as an electrode for depositing or dissolving silver, in contact with these electrodes. The optical device described in 1. 5. The optical device according to claim 1, wherein a solution in which silver halide as the silver salt is dissolved in water or a non-aqueous solvent is arranged, and coloring or decoloring is caused by precipitation or dissolution of silver. 6. The optical device according to claim 1, wherein silver chloride is used as the silver salt. 7. The optical device according to claim 1, wherein a solution having a silver salt concentration of 0.03 to 2.0 mol / L is used. 8. The optical device according to claim 1, wherein a brightening agent and / or a reducing agent is added to the solution. 9. The non-aqueous solvent is dimethylformamide, diethylformamide, N, N-dimethylacetamide, N-methylpropionamide, N-methylpyrrolidone, propylene carbonate, acetonitrile, 2
The optical device according to claim 5, comprising at least one selected from the group consisting of: ethoxyethanol, 2-methoxyethanol, dimethylsulfoxide, dioxolane, ethyl acetate, tetrahydrofuran, methyltetrahydrofuran, dimethoxyethane and γ-butyrolactone. 10. The optical device according to claim 5, wherein a supporting salt capable of supplying the same or different halogens for dissolving the silver halide is added to complex the silver halide. 11. The supporting salt is 1/2 of the silver halide.
11. The optical device according to claim 10, wherein the optical device is added in a range of double density to 5 times density. 12. The transparent electrode, which serves as a working electrode for depositing or dissolving silver, is made of indium-tin oxide.
The optical device according to claim 1. 13. The optical device according to claim 12, wherein the transparent electrode is chemically or physically modified. 14. A solution of a silver salt, which is disposed between opposed electrodes and causes precipitation or dissolution of silver by controlling driving of these electrodes, 1,4-benzodioxane, 2-hydroxymethyl
1,4-benzodioxane, 1,2-methylenedioxybenzene, quinoxaline, phthalide, salicylmethyl ester, 4-hydroxycoumarin, 7-dimethylamino-4-methylcoumarin, coumarinic acid, coumarin, 6-methylcoumarin, 3 , 4-dihydro-2H-pyran, dehydroacetic acid, thiouracil, thiourea, 1-allyl-2-
Thiourea, 2-mercaptothiazoline, mercaptobenzimidazole, aminobenzothiazole, phthalimide, phthalic anhydride, phthalic acid, succinic acid, salicylic acid,
Salicylaldehyde, salicylamide, salicylanilide, glycolic acid, tartaric acid, oxalic acid, dimethylamine borane, trimethylamine borane and D-glucono-
At least one selected from the group consisting of 1,5-lactones
Electrolyte solution to which seed additives are added. 15. The electrolytic solution according to claim 14, wherein the additive does not dissolve the electrode and has a function of promoting precipitation or dissolution of silver. 16. The electrolytic solution according to claim 14, wherein the amount of the additive added is 0.1 to 200 g / L. 17. The electrolytic solution according to claim 14, which is filled between the opposed electrodes, at least one of which serves as an electrode for depositing or dissolving silver, in contact with these electrodes. 18. The electrolytic solution according to claim 14, wherein a solution in which silver halide as the silver salt is dissolved in water or a non-aqueous solvent is arranged, and coloring or decoloring is caused by precipitation or dissolution of silver. 19. The electrolytic solution according to claim 14, wherein silver chloride is used as the silver salt. 20. The electrolytic solution according to claim 14, wherein a solution having a silver salt concentration of 0.03 to 2.0 mol / L is used. 21. The electrolytic solution according to claim 14, wherein a brightening agent and / or a reducing agent is added to the solution. 22. The non-aqueous solvent is dimethylformamide, diethylformamide, N, N-dimethylacetamide, N-methylpropionamide, N-methylpyrrolidone, propylene carbonate, acetonitrile, 2
The electrolytic solution according to claim 18, comprising at least one selected from the group consisting of: ethoxyethanol, 2-methoxyethanol, dimethylsulfoxide, dioxolane, ethyl acetate, tetrahydrofuran, methyltetrahydrofuran, dimethoxyethane and γ-butyrolactone. 23. The electrolytic solution according to claim 18, wherein a supporting salt capable of supplying the same or different halogens for dissolving the silver halide is added to complex the silver halide. 24. The supporting salt is 1/2 of the silver halide.
24. The electrolytic solution according to claim 23, which is added in a range of double concentration to 5 times concentration. 25. The transparent electrode serving as a working electrode for depositing or dissolving silver is made of indium-tin oxide.
The electrolytic solution according to claim 14. 26. The electrolytic solution according to claim 25, wherein the transparent electrode is chemically or physically modified.