JPH09297324A - Optical device and electrolyte - Google Patents

Abstract

(57) [Problem] To be driven with low power consumption, to be able to control light transmittance in a visible light range, to have good spectral characteristics at the time of light shielding, and to prevent overvoltage on electrodes. To provide an optical device capable of prolonging its life and an electrolytic solution used for the optical device. SOLUTION: A counter electrode 2 is a solution 1 in which silver bromide is dissolved in a solvent and a metal salt such as copper bromide is added as a co-deposited metal of silver.
An optical device which is arranged between 3 and 3 and is configured to cause silver deposition or dissolution by driving control of these electrodes.

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 dimming element, although the response speed and the light shielding degree can obtain a target value, the transparent electrode serving as the substrate is easily deteriorated and the life of the device is shortened. Was short-lived.

In particular, an overvoltage is applied to an ITO (Indium Tin Oxide) electrode during silver precipitation and dissolution, so that the electrode is easily damaged.

[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
(0 nm) has no absorption, and a silver complex salt capable of almost evenly shielding in the visible light region during coloring is used as an electrochemical light control element material, and it is possible to reduce the overvoltage to the electrode and achieve a long service life. It is to provide an optical device and an electrolytic solution used for the optical device.

[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, and have good spectral characteristics. The present invention has arrived at the present invention by finding a stable optical device and an electrolytic solution in which the damage of (1) is reduced.

That is, according to the present invention, a solution of a silver salt is arranged between opposing electrodes, and the silver is co-deposited with a dissimilar metal such that silver is deposited or dissolved by controlling the driving of these electrodes. The present invention relates to the optical device and the electrolytic solution including the solution to which the dissimilar metal is added.

Up to now, even if an electrolytic solution of a practical level is obtained, as described above, the transparent electrode serving as the substrate deteriorates due to repeated driving, so that the life is short.
According to the present invention, by co-depositing silver with a dissimilar metal (for example, copper as a copper salt), it has succeeded in reducing the dissolution overvoltage of the deposited silver film, and the deposition / precipitation of silver, which is an important factor of the lifetime. It was possible to reduce the overvoltage of melting and achieve a longer electrode life.

Thus, according to the present invention, deterioration of the electrode (particularly the ITO transparent electrode) can be avoided by reducing the dissolution overvoltage of the deposited silver film. In fact, when a life test was attempted using an ITO electrode, the life was extended by 10 to 40 times that in the case of using a conventional electrolytic solution (system containing no Cu salt).

In order to effectively exert such an effect, it is preferable to add the above-mentioned dissimilar metals in a salt form at a rate of 0.1 to 100 mmol / L.

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

That is, a reversible system was obtained by adding a reducing agent from the electrolytic solution of various silver complex salts. Materials used in this system RED (R eversible E lectro
It referred to as D eposition) materials were prepared RED solution dissolved in a solvent.

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 non-aqueous 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, when silver bromide having a relatively high standard redox potential is used as the silver salt, the above-mentioned coloring side reaction gas generated during silver dissolution is reduced, and the deposited silver film is exposed to visible light. We can obtain a system with uniform absorption in the 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 when colored, a substantially uniform shield is obtained in the visible light range. It is desirable to use possible silver bromide (complex salt) as a material. In addition, this silver bromide (complex salt) is rich in reversibility of precipitation-dissolution by drive control.

As described above, the present invention is particularly suitable for the non-emission type visible light region with low power consumption by using a reversible system in which silver is deposited and dissolved on the electrode from a silver salt of silver bromide. It is possible to provide various optical devices such as a display device and an optical filter.

In the optical device of the present invention, when the dissimilar metal is dissolved in the solution, it is desirable that the solution is not colored.

As the dissimilar metal, copper is used, which may be contained in the solution as copper halide such as copper chloride and copper bromide.

When the copper halide is dissolved in the solution,
If the solution is colored, it should be clarified by a clarifying agent (eg complexing agent or reducing agent). That is, since this device is arranged in the optical system, it is not desirable that the electrolytic solution has absorption in the visible light region, but normally, when copper halide is dissolved in an organic solvent, it has absorption in the visible light region. On the other hand, in the present invention, the dissolved copper salt is converted into Cu ²⁺ + e ⁻ → Cu ⁺ (colored) (colorless) by using a clarifying agent typified by triethanolamine. By reducing or complexing with, the light absorption of the electrolytic solution in the visible light region can be sufficiently avoided.

The above-mentioned clarifying agent is generally a complexing agent,
A reducing agent, for example, triethanolamine, iminodiacetic acid, trans-1,2-cyclohexanediaminetetraacetic acid, nitrilotriacetic acid, galactitol, ascorbic acid, dimethylamine borane, trimethylamine borane, tetrabutylammonium borate, triethanolamine borate. , N, N, N ', N'-tetrakis (2-hydroxypropyl) ethylenediamine, ethylenediamine-N, N, N', N'-tetraacetic acid, salicylic acid, 2-mercaptobenzimidazole, 1-allyl-2-thio At least one selected from the group consisting of urea, thiouracil and dimethylthioformamide can be used.

In the above clarifying agent, as the complexing agent, triethanolamine, iminodiacetic acid, trans-
1,2-cyclohexanediaminetetraacetic acid, nitrilotriacetic acid, galactitol and the like can be mentioned, and as the reducing agent, ascorbic acid, dimethylamine borane,
Examples include trimethylamine borane and tetrabutylammonium borate.

The optical device of the present invention is constituted 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 bromide is dissolved in water or a non-aqueous solvent, particularly a non-aqueous solution, is arranged, and it is desirable that the solution is colored or decolored by the precipitation or dissolution of silver.

In this case, the concentration of silver bromide 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, a complexing agent and a reducing agent is preferably added to the solution.

For example, at least one (generally a brightening agent) selected from the group consisting of thiourea, 1-allyl-2-thiourea, mercaptobenzimidazole and coumarin.
May be used.

Further, at least one (generally a complexing agent) selected from the group consisting of phthalic acid, succinic acid, salicylic acid and glycolic acid may be used.

Ascorbic acid, dimethylamine borane (DMAB), trimethylamine borane (TMA)
At least one (generally a reducing agent) selected from the group consisting of B), tartaric acid, oxalic acid and D-glucono-1,5-lactone 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 this result, as a reducing agent applicable to a solvent having a low freezing point, which has not been studied at all,
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 a concentration range of 1/150 to 1 time 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) and 2-ethoxyethanol (EEO).
A solvent (non-aqueous solvent) consisting of at least one selected from the group consisting of H) 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 bromide, has excellent low-temperature characteristics,
For example, it will be sufficiently durable for use in cold regions.

In order to increase the conductivity of the RED liquid,
The supporting salt is preferably added to the solution in a concentration of 1/2 to 5 times that of silver iodide.

In order to increase the conductivity of the RED solution and to dissolve silver bromide, a supporting salt (supporting electrolyte) capable of supplying bromine and other halogens is added to complex silver bromide. desirable. Examples thereof include sodium bromide, potassium bromide, calcium bromide, and quaternary ammonium bromide.

It is preferable that the supporting salt is added in a concentration range of 1/2 to 5 times that of silver bromide.

The transparent electrode (particularly ITO electrode: obtained by doping indium oxide with tin) to serve as a working electrode for depositing or dissolving silver is chemically or physically modified to form a transparent electrode. It is possible to lower the deposition potential of silver to the silver, facilitate the deposition and dissolution of silver, and reduce the electrical damage to the transparent electrode and the solution itself.

As a chemical modification method in this case, it is preferable to perform 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 ) was 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 of depositing a metal, which is more precious than silver, 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 colored and decolored states are repeated using the RED solution, the solution system cannot be stirred because the device is minute. 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 for coloring-decoloring by controlling the current as described above, in order to increase the coloring-decoloring speed (silver deposition, dissolution rate), a current that changes from a high current value to a low current value in a rectangular shape. It is preferable to use the driving method according to. 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 can display 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-mentioned silver salt and different metals in a solvent.

This electrolytic solution comprises a solution in which a silver salt such as silver bromide 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 above-mentioned additive of the present invention is added, and in some cases, a brightening agent, a complexing agent, a reducing agent, a supporting salt, and a solvent can be contained in predetermined amounts.

[0052]

Embodiments of the present invention will be described below.

First, referring to FIGS. 7 and 8, an optical device such as a display element (or an optical filter) according to the embodiment of the present invention.
An example of 10 is schematically shown.

According to the optical device 10 of this example, a pair of transparent substrates (for example, glass plates) 4 and 5 which constitute a cell are arranged as a display window with a constant interval, 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.

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

Then, a RED liquid 1 in which silver bromide (complex salt), copper bromide and the like as a RED material is dissolved in a non-aqueous solvent is enclosed between the counter electrodes 2-3 in contact with these electrodes. There is. One of the counter electrodes 2 and 3 is used as an anode and the other is used as a cathode. By applying a DC drive voltage between them for a predetermined time, 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. 9 and 10, 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. 8), 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 described divided electrodes 2a-3a, 2b-3b.
Between the divided electrodes on the cathode by the voltage (V ₁ , V ₂ , V ₃ , V ₄ , and V ₅ , respectively) applied between 2c-3c, 2d-3d, and 2e-3e. RED
The amount of silver deposited from the liquid can be changed (note that
The voltage V ₆ for potential compensation is also applied between the counter electrodes 6A and 6B).

Therefore, if all the voltages are equalized (V ₁ = V ₂ = V ₃ = V ₄ = V ₅ ), the RED liquid 1 can be colored uniformly over the entire area, and the voltage can be made uniform. It is possible to uniformly change the degree of concentration according to the above.

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 increases from the center to the periphery (in other words If the transmittance is 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.

In this way, the gradation 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 the present embodiment, the RED material made of silver bromide is used as the filter material for controlling the light amount of the optical device, based on the idea completely different from the conventional EC material. By controlling the drive of the counter electrode (especially the applied voltage), it is possible to change the shade of the RED material during coloring, 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 a RED solution prepared by dissolving silver bromide 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 copper bromide was added to the RED solution, silver and copper were co-deposited on the ITO transparent electrode, and no overvoltage was applied to this transparent electrode, and no damage was caused.

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. 7 and 8 was used.

Example 1 (Cyclic voltammetry (C
V) Characteristic Evaluation Using Measurement Method) Silver bromide was used in order to study a system of reversible silver precipitation and dissolution. In this example, the purpose was to investigate the precipitation and dissolution properties of silver.

As the solvent, dimethylformamide (D
MF) was used. The silver bromide concentration was 0.5 mol / L, and a quaternary ammonium salt [Tetra-n-butyl ammonium bromide (TBAB)] was used for the purpose of dissolving it and increasing the conductivity. .
0 mol / L was dissolved. Also, thiourea as a brightener is 1.
0 g / L was dissolved. Furthermore, copper bromide (CuBr ₂ ) was dissolved at 2.2 mmol / L as a copper supply source for co-depositing silver. After dissolution of CuBr ₂ , the solution turns purple, but by dissolving a considerable amount of triethanolamine,
The solution could be clarified. This clarified solution was used as an electrolytic solution in an experiment.

In this way, CV measurement was carried out for the electrolytic solution in which CuBr ₂ was dissolved and the electrolytic solution in which CuBr ₂ was not dissolved. The working electrode is an ITO electrode, the counter electrode is a silver plate, and the reference electrode is a silver wire. The sweep speed was 100 mV / sec for both experiments. Fig. 1 shows an electrolytic solution in which CuBr ₂ is dissolved, and Fig. 2 shows CuBr.
The CV curve when using the electrolyte solution which does not dissolve ₂ is shown.

According to this, in the system in which CuBr _{2 is} not added, the "remaining residue" is finally completely erased at around + 2.0V. On the other hand, in the system with CuBr ₂ added, it dissolves (oxidizes) around + 1.6V with respect to silver on the CV curve.
The second peak of appears. In other words, in the presence of Cu salt, it can be seen that about +1.5 V to +2.0 V (vs. Ag) causes an excessive overvoltage, which is due to co-deposition of silver salt and copper salt, This means that the conductivity was successfully increased, and the second peak appears on the oxidation side of +2.0 V or less, so that the overvoltage required to completely erase the "remaining residue" can be suppressed. It was

Further, as is clear from the CV curve shown in FIG. 1, it can be seen that the electrolytic solution according to this example has a large dissolution peak on the oxidation side and is a reversible system.

Example 2 (Change in transmittance in silver deposition / dissolution using potentiostatic method) Using the electrolytic solution containing Cu salt obtained in Example 1, an attempt was made to deposit / dissolve silver by potentiostatic method. The change in transmittance at that time was measured.

The driving voltage at the time of precipitation was −2.5 V with respect to silver, and the driving time was 1.5 seconds. On the other hand, the driving voltage at the time of melting is driving stepwise, + 4.5V with respect to silver,
It was 20msec → + 1.6V, 2sec → + 3.5V, 20msec. The changes in the respective transmittances are shown in FIG. 3 (during deposition) and FIG. 4 (during dissolution). The transmittance at this time is based on the transmittance of the ITO electrode.

From these results, it can be seen that the amount of light can be adjusted (the transmittance can be changed) when the present electrolytic solution is used. The spectral characteristics of the deposited silver film in this system have a uniform absorption in the visible light region, and show that the transmittance fluctuates similarly in both deposition and dissolution, indicating that the film has light shielding ability in the visible light region. It indicates that.

In this example, FIGS. 5 and 6 show changes in transmittance when an electrolytic solution having the same composition except that CuBr ₂ was not added was used and driven at a low speed. According to this, it can be seen that the change in transmittance is obtained in the visible light region.

However, when the above electrolyte solution containing CuBr ₂ was used, the life test of the ITO electrode was tried, and it was 10 to 40 times that of the above-mentioned conventional electrolyte solution containing no CuBr _2. It was confirmed that the life was extended about twice as long. As a result, it was found that it is important to add CuBr ₂ to suppress the overvoltage on the oxidation side in order to prolong the life of the device.

Example 3 (Cryogenic Storage Test of Non-Aqueous Solvent) The freezing points of various non-aqueous solvents are summarized in Table 1 below.

[0081]

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

[0083]

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 4 (Clearing test) A transparentizing test was carried out for the purpose of investigating the effectiveness of the clarifying agent with respect to the electrolytic solution in the optical device constructed as shown in FIGS. 7 and 8. .

As the solvent, dimethyl sulfoxide (DM
SO) was used. The silver bromide concentration was set to 500 mmol / L, and a quaternary ammonium salt [Tetra-n-butyl ammonium bromide (TBAB)] was added for the purpose of dissolving it and increasing the conductivity.
750 mmol / L was dissolved. Further, 0.1 mmol / L of copper bromide (CuBr ₂ ) was dissolved as a supply source for co-depositing silver. The results of this transparency test are shown in Table 3 below.

However, the transparency was measured by using HP8452A manufactured by Yokogawa Hewlett-Packard Co., and a transmittance of 80% or more at a wavelength of 400 nm was evaluated as "A". In addition, the result 1 shows the result immediately after adding the clarifying agent, and the result 2
Shows the results after standing for 24 hours at a temperature of 80 ° C. temperature
Allowing it to stand at 80 ° C for 24 hours is, for example, when ascorbic acid is used as a clarifying agent, under normal conditions 2,4
The environment is more severe than leaving it for 00 hours.

[0088]

From Table 3, extremely excellent transparency was obtained for the result 1. As for the result 2, although some of the samples were colored, it was not a problem in practical use. However, in Table 3, the black cotton precipitate means that a black cotton-like precipitate is formed, and the recrystallized precipitate means that dimethylthioformamide is recrystallized and precipitated.

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 combination, concentration, etc. of the liquid D component, especially the dissimilar metal co-deposited with silver may be variously changed.

The material of each component, including the structure including the ITO electrode pattern, and the driving method are not limited to those described above. For example, the electrode pattern as shown in FIG. 9 may be variously changed into a stripe shape, a grid shape, or the like, or different RED liquid cells may be divided and juxtaposed 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.

[0094]

The present invention, as described above, is a conventional EC.
RE containing silver salt based on an idea completely different from the material
In liquid D, a dissimilar metal that co-deposits with silver is added, and a reversible system is formed in which silver is deposited and dissolved on the electrode by drive control (particularly applied voltage) of the counter electrode. Therefore, RE
By using the D material, it is possible to provide an optical device that consumes less power and is suitable for a non-emission type visible light region, and at the same time, it is possible to reduce the overvoltage to the electrodes and achieve a long life.

[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 an optical device according to a comparative example.

FIG. 3 is a spectrum diagram showing a change in transmittance due to an applied voltage during coloring of the optical device according to the present invention.

FIG. 4 is a spectrum diagram showing a change in transmittance according to an applied voltage when a color of the optical device according to the present invention is erased.

FIG. 5 is a spectrum diagram showing a change in transmittance depending on an applied voltage when coloring an optical device according to a comparative example.

FIG. 6 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. 7 is a schematic sectional view of the optical device.

FIG. 8 is a conceptual diagram of the optical device.

FIG. 9 is an ITO electrode pattern diagram of a specific example of the optical device.

FIG. 10 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 (38)

[Claims] 1. An optical system in which a solution of a silver salt is arranged between opposed electrodes, and the silver is co-deposited with a dissimilar metal by controlling the driving of these electrodes to cause precipitation or dissolution of silver. apparatus. 2. The optical device according to claim 1, wherein when the dissimilar metal is dissolved in the solution, the solution is not colored. 3. The optical device according to claim 1, wherein copper is used as the dissimilar metal. 4. The optical device according to claim 3, wherein the dissimilar metal is contained in the solution as copper halide. 5. The content of dissimilar metals is 0.1 to 100 m in the form of salt.
The optical device according to claim 1, which is mol / L. 6. The optical device according to claim 4, wherein when the copper halide is dissolved in the solution, the solution is colored by a clearing agent when the solution is colored. 7. Triethanolamine, iminodiacetic acid,
Trans-1,2-cyclohexanediaminetetraacetic acid, nitrilotriacetic acid, galactitol, ascorbic acid, dimethylamine borane, trimethylamine borane,
Tetrabutylammonium borate, triethanolamine borate, N, N, N ′, N′-tetrakis (2-
Hydroxypropyl) ethylenediamine, ethylenediamine-N, N, N ', N'-tetraacetic acid, salicylic acid,
2-mercaptobenzimidazole, 1-allyl-2-
The optical device according to claim 6, wherein at least one selected from the group consisting of thiourea, thiouracil, and dimethylthioformamide is used as a clarifying agent. 8. The electrolytic solution in which a silver salt is dissolved in a solvent is filled between opposing electrodes, at least one of which serves as a silver deposition or dissolution electrode, in contact with these electrodes. Optical device. 9. The optical device according to claim 1, wherein a solution in which silver bromide is dissolved in water or a non-aqueous solvent is arranged, and coloring or decoloring is caused by precipitation or dissolution of silver. 10. The optical device according to claim 1, wherein a solution having a silver bromide concentration of 0.03 to 2.0 mol / L is used. 11. The optical device according to claim 1, wherein at least one additive selected from the group consisting of a brightening agent, a complexing agent and a reducing agent is added to the solution. 12. The optical device according to claim 11, wherein at least one selected from the group consisting of thiourea, allylthiourea, mercaptobenzimidazole and coumarin is used. 13. The optical device according to claim 11, wherein at least one selected from the group consisting of phthalic acid, succinic acid, salicylic acid, and glycolic acid is used. 14. The optical device according to claim 11, wherein at least one selected from the group consisting of ascorbic acid, dimethylamine borane, trimethylamine borane, tartaric acid, oxalic acid, and gluconolactone is used. 15. The non-aqueous solvent is dimethylformamide, diethylformamide, N, N-dimethylacetamide,
10. The composition according to claim 9, comprising at least one selected from the group consisting of N-methylpropionic acid amide, N-methylpyrrolidone, propylene carbonate, acetonitrile, 2-ethoxyethanol, 2-methoxyethanol and γ-butyrolactone. Optical device. 16. The optical device according to claim 9, wherein a supporting salt capable of supplying bromine or other halogen is added to dissolve silver bromide, and silver bromide is complexed. 17. The optical device according to claim 16, wherein the supporting salt is added in the range of ½ to 5 times the concentration of silver bromide. 18. The optical device according to claim 1, wherein the transparent electrode serving as a working electrode for depositing or dissolving silver is made of indium-tin oxide. 19. The optical device according to claim 18, wherein the transparent electrode is chemically or physically modified. 20. An electrolytic solution which is arranged between opposed electrodes and which is composed of a solution of a silver salt which causes precipitation or dissolution of silver by controlling the driving of these electrodes, and which contains a dissimilar metal for co-depositing the silver. 21. The electrolytic solution according to claim 20, wherein when the dissimilar metal is dissolved in the solution, the solution is not colored. 22. Copper is used as the dissimilar metal,
Electrolyte solution described in 21. 23. The electrolytic solution according to claim 22, wherein the dissimilar metal is contained as copper halide. 24. The content of dissimilar metals in the form of a salt is 0.1 to 100 m.
The electrolytic solution according to claim 20, which is mol / L. 25. The electrolytic solution according to claim 23, wherein when the copper halide is dissolved in the solution, the solution is colored by a clearing agent when the solution is colored. 26. Triethanolamine, iminodiacetic acid,
Trans-1,2-cyclohexanediaminetetraacetic acid, nitrilotriacetic acid, galactitol, ascorbic acid, dimethylamine borane, trimethylamine borane,
Tetrabutylammonium borate, triethanolamine borate, N, N, N ′, N′-tetrakis (2-
Hydroxypropyl) ethylenediamine, ethylenediamine-N, N, N ', N'-tetraacetic acid, salicylic acid,
2-mercaptobenzimidazole, 1-allyl-2-
26. The electrolytic solution according to claim 25, wherein at least one selected from the group consisting of thiourea, thiouracil and dimethylthioformamide is used as a clarifying agent. 27. The electrolytic solution according to claim 20, which 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. 28. The electrolytic solution according to claim 20, wherein a solution in which silver bromide is dissolved in water or a non-aqueous solvent is arranged, and coloring or decoloring is caused by precipitation or dissolution of silver. 29. The electrolytic solution according to claim 20, wherein a solution having a silver bromide concentration of 0.03 to 2.0 mol / L is used. 30. The electrolytic solution according to claim 20, wherein at least one additive selected from the group consisting of a brightening agent, a complexing agent and a reducing agent is added to the solution. 31. The electrolytic solution according to claim 30, wherein at least one selected from the group consisting of thiourea, allylthiourea, mercaptobenzimidazole and coumarin is used. 32. The electrolytic solution according to claim 30, wherein at least one selected from the group consisting of phthalic acid, succinic acid, salicylic acid, and glycolic acid is used. 33. The electrolytic solution according to claim 30, wherein at least one selected from the group consisting of ascorbic acid, dimethylamine borane, trimethylamine borane, tartaric acid, oxalic acid and gluconolactone is used. 34. The non-aqueous solvent is dimethylformamide, diethylformamide, N, N-dimethylacetamide,
29. The composition according to claim 28, which comprises at least one selected from the group consisting of N-methylpropionic acid amide, N-methylpyrrolidone, propylene carbonate, acetonitrile, 2-ethoxyethanol, 2-methoxyethanol and γ-butyrolactone. Electrolyte. 35. The electrolytic solution according to claim 28, wherein a supporting salt capable of supplying bromine or another halogen is added to dissolve silver bromide, and silver bromide is complexed. 36. The electrolytic solution according to claim 35, wherein the supporting salt is added in the range of 1/2 to 5 times the concentration of silver bromide. 37. The electrolytic solution according to claim 20, wherein the transparent electrode serving as a working electrode for depositing or dissolving silver is made of indium-tin oxide. 38. The electrolytic solution according to claim 37, wherein the transparent electrode is chemically or physically modified.