JP4470451B2 - Method for producing electrochemical dimmer and method for producing polymer electrolyte - Google Patents

Description

  The present invention relates to an electrochemical light control device and a polymer electrolyte suitable as an electrochemical display device or the like that displays image information by an electrochemical redox reaction.

  In recent years, with the spread of networks, documents that have been distributed in the form of printed materials so far have been distributed as so-called electronic documents. Furthermore, books and magazines are often provided in the form of so-called electronic publishing.

  In order to browse these pieces of information, it is generally performed to display images on a CRT (Cathode Ray Tube) or liquid crystal display of a computer. However, it has been pointed out that the operation of viewing these luminescent displays is apt to cause fatigue for a physiological reader for ergonomic reasons and is not suitable for long-time reading. In addition, there is a difficulty that the place where the computer can be used is limited to the place where the computer is installed.

  Recently, portable displays have been developed with the spread of small computers. If this is used, the problem of the place of use is somewhat mitigated, but due to the relationship between the capacity of the built-in battery and the power consumption, it cannot be used continuously for several hours. In addition, if the display is a light emitting type, it is still not suitable for long-time work.

  In recent years, reflective liquid crystal displays have also been developed. If this is used, it is expected that the above-mentioned difficulties caused by the light-emitting display will not occur, and that it can be driven for a long time with low power consumption. However, since the reflectance in the non-display (white display) state is only 30%, the visibility is remarkably worse than that printed on paper. For this reason, it tends to cause fatigue to the user and is not suitable for long-time use.

  In order to solve these problems, what is called a paper-like display or electronic paper is being developed recently. These are colored by, for example, moving colored particles between electrodes by electrophoresis or rotating particles having dichroism in an electric field. However, in these methods, the gap between particles absorbs light and the contrast is deteriorated, and a practical writing speed (within 1 second) cannot be obtained unless the driving voltage is set to 100 V or more. There are difficulties.

  On the other hand, an electrochemical display device (ECD: Electric Chromic Display or EDD: Electro-Deposition Display) that displays information by discoloration due to electrochemical action is applied to an electrophoretic method in terms of high contrast. It is superior to the above and has already been put to practical use in light control glass and watch displays. However, the electrochemical display device used for the light control glass or the clock display does not have a matrix driving function, and cannot be applied to an electronic paper display or the like as it is. In general, the black quality is poor and the reflectance is low. Japanese Patent Publication No. 4-73767 discloses a matrix driving device, but there is no specific description about an electrochemical display device.

  Further, in an electrochemical display device that has been put into practical use for light control glass or a watch display, an organic material is used to form a black portion. Because organic materials have poor light resistance, they are discolored when used for a long time, such as electronic paper displays, and are exposed to light such as sunlight and room light. Problems arise.

  In order to solve the technical problems as described above, the applicant of the present invention uses silver iodide or the like containing metal ions such as silver ions as a color variable material that changes color by an electrochemical redox reaction. Used as a material to dissolve this, a polymer electrolyte that is colored in white and contains a supporting electrolyte such as lithium iodide, can be driven by a matrix, and can increase contrast and black density. A display element and an electrochemical display device have been proposed (see Patent Document 1 described later).

  According to the electrochemical display element of Patent Document 1, a coloring material such as titanium dioxide is dispersed in the polymer electrolyte, and the polymer electrolyte is colored white by this coloring material. And high contrast and black density | concentration can be obtained by whitening a polymer electrolyte using coloring materials, such as titanium dioxide.

JP 2002-258327 A (pages 7 to 12, FIGS. 3, 4 and 8 to 12)

However, the electrochemical display element of the above-mentioned Patent Document 1 does not dissolve iodine which is an anion species in the polymer electrolyte when dissolving the color variable material such as silver deposited on the electrode, that is, during the oxidation reaction of the color variable material. Oxidation reaction may occur. For example, when silver iodide is used as the color variable material, lithium iodide is used as the supporting electrolyte, and iodine ions are contained in the polymer electrolyte, if the color variable material is over-erased after dissolution reaction, 2I ⁻ → I ₂ + 2e ^-
Iodine is produced by the reaction represented by

When iodine is generated by the reaction described above, a part of the current is consumed by the iodine reduction reaction (I ₂ + 2e ⁻ → 2I ⁻ ) even if silver precipitation reaction (reduction reaction) is attempted at the same electrode. As a result, the desired amount of silver is not deposited, and the writing density is reduced in terms of display characteristics.

Further, when highly oxidizable iodine is present around the precipitated silver, the precipitated silver is oxidized by iodine, and the following reaction formula 2Ag + I ₂ → 2Ag ⁺ + 2I ⁻
Causes silver to elute. That is, this phenomenon means deterioration of memory characteristics.

  Here, iodine which is a problem can be prevented from being generated by driving at about +0.8 V or less with respect to the silver potential. However, in that case, the response time is delayed to about 2 seconds. Therefore, when the response time is within 0.2 seconds, for example, it is necessary to set +2.0 V or more with respect to the silver potential, and generation of iodine cannot be made zero.

  The present invention has been made in order to solve the above-described problems. The purpose of the present invention is, for example, once an input operation for displaying is performed, and then an input for switching to another display state is performed. It is suitable for an electrochemical dimming device that is excellent in display memory property that can maintain its display state until operation is performed, that is, can achieve low power consumption as a device, and the electrochemical dimming device. The object is to provide a polymer electrolyte to be used.

  That is, the present invention provides a polymer electrolyte layer containing a color variable material that changes color or disappears by electrochemical reduction or oxidation and precipitation or dissolution associated therewith, an electrolyte, and a polymer compound. And the second electrode, wherein at least a part of the color variable material and at least a part of the electrolyte use different halogens as anion species. The present invention relates to an electrochemical light control device.

  In addition, it contains a color variable material that is discolored or decolored by electrochemical reduction or oxidation and accompanying precipitation or dissolution, an electrolyte, and a polymer compound, and includes at least a part of the color variable material and the electrolyte. At least a part relates to a polymer electrolyte using halogens different from each other as anion species.

  Here, the “polymer electrolyte” in the present invention means a polymer material containing the electrolyte and a solvent.

  According to the present invention, since at least a part of the color variable material and at least a part of the electrolyte use different halogens as anion species, only iodine is used as the anion species as in the conventional example described above. Compared to the case, the amount of iodine generated in the over-erased state can be significantly reduced after the dissolution reaction of the color variable material.

  Accordingly, when depositing the color variable material, it is possible to reduce the consumption of a part of the current for the reduction reaction of iodine as in the conventional example, so that the desired amount of the color variable material can be easily obtained. It can be deposited, and the display characteristics as a device can be improved. In addition, since the deposited color variable material can be reduced from being oxidized and eluted by iodine, the memory characteristics of the device can be improved. Furthermore, by using different halogens as the anion species, it becomes possible to improve response characteristics particularly at low temperatures.

  In the present invention, it is preferable that the color variable material contains silver ions and the electrolyte contains lithium ions. The reason why silver is suitable is that reversible reaction can be easily advanced and the degree of discoloration during precipitation is high. Lithium can impart high conductivity to the polymer electrolyte layer.

  Further, the different halogens are not particularly limited, but it is preferable that one of the different halogens is iodine, and that one of the different halogens is iodine and the other is bromine. preferable. The reason why iodine is preferable is that it bonds more strongly with silver ions than other halogens and forms a stable complex, that is, has good light resistance. In order to shorten the response time, generation of iodine due to a peroxidation state is inevitable. Therefore, the generation amount of iodine can be effectively suppressed by including bromine having an oxidation potential more noble than iodine as an ionic species. For example, in a system composed of a bromine ion species such as AgBr used as the color variable material and LiBr used as the electrolyte, the reaction is not reversible and cannot be used.

  Specifically, it is preferable that the color variable material is AgI and the electrolyte is LiBr. Alternatively, it is preferable that the color variable material is AgBr and the electrolyte is LiI. Further, the color variable material may be made of AgI and AgBr, and the electrolyte may be made of LiI and LiBr.

  The concentration of the silver ions is preferably 0.5M or more and 2.0M or less, whereby the memory characteristics and response characteristics (especially low temperature) can be further improved. Among the above ranges, the range is more preferably 0.75 M or more and 1.0 M or less, whereby the memory characteristics and response characteristics (especially low temperature) can be more effectively improved.

  Moreover, it is preferable that the density | concentration of the said lithium ion is 1.3 times-1.5 times (molar ratio) of the density | concentration of the said silver ion.

  The electrochemical light control device according to the present invention has a higher silver ion concentration than the conventional device. In general technique such as plating, in order to carry out more precise plating, (1) raise the temperature of the plating bath, (2) raise the concentration of salt, (3) suitable additives (brightener, stress (4) Slowly plating at a low current density is performed. (4) Slow diffusion is performed so that the ion distribution in the bath is uniform. The electrochemical light control device of the present invention also uses a reversible plating reaction, and the above methods (1) to (5) should be applicable. However, (2) or (3) is applicable as the light control device. Therefore, the present inventor has intensively studied and found that the reversible plating reaction can be more effectively performed by the above method (2), that is, without particularly using an additive by increasing the concentration of the salt. I found. Further, it is considered that dendrite generation due to irreversibility of the silver precipitation dissolution reaction can be suppressed by increasing the concentration of the salt, and according to this, it is possible to extend the life of the device.

  Hereinafter, an electrochemical display device according to an embodiment of the present invention will be described in detail with reference to the drawings. This electrochemical display device has a structure in which a plurality of electrodeposition display elements are arranged in a planar shape.

First Embodiment FIG. 1 is a schematic perspective view of an example of an electrochemical light control device according to the present invention configured as an electrochemical display device, and FIG. 2 is a schematic sectional view thereof.

  As shown in FIG. 1, in this electrochemical display device, a common transparent electrode 5 is formed on a transparent electrode support 6 which is one substrate. The second electrode 1 is divided and formed in a matrix on the support 3 that is the other substrate, and each separated second electrode 1 constitutes one pixel. A thin film transistor (TFT) 2 is provided for each second electrode 1 so that each pixel can be driven independently.

  As the transparent electrode support 6, a transparent glass substrate such as a quartz glass substrate or a white plate glass substrate can be used, but is not limited to this, and a transparent resin substrate can also be used. For example, polyesters such as polyethylene naphthalate and polyethylene terephthalate, cellulose esters such as polyamide, polycarbonate, and cellulose acetate, fluoropolymers such as polyvinylidene fluoride and polytetrafluoroethylene-cohexafluoropropylene, and polyethers such as polyoxymethylene Polyacetal, polyethylene, polypropylene, polyolefin such as methylpentene polymer and polystyrene, and polyimide such as polyimide-amide and polyetherimide. When these synthetic resins are used as the transparent electrode support 6, it is possible to form a rigid substrate that does not bend easily, but it is also possible to form a flexible film-like structure.

The common transparent electrode 5 is made of a transparent conductive film. As the transparent conductive film, a mixture of indium oxide (In ₂ O ₃ ) and tin oxide (SnO ₂ ), so-called ITO (Indium Tin Oxide) film, tin oxide (SnO ₂ ), or indium oxide (In ₂ O ₃ ) It is preferable to use a film coated with. These ITO films, tin oxide (SnO ₂ ) or indium oxide (In ₂ O ₃ ) coated films may be doped with tin (Sn) or antimony (Sb), and may be magnesium oxide (MgO) or zinc oxide (ZnO). Or the like can be used.

  As shown in FIG. 1, on the side facing the common transparent electrode 5, a film made of a good electrical conductor such as a metal film is formed on the support 3 in a matrix and the second electrode 1 is provided. The second electrode 1 may be any electrochemically stable metal, but is preferably platinum, chromium, aluminum, cobalt, palladium, or the like. Furthermore, if the metal used for the main reaction can be sufficiently supplemented in advance or as needed, carbon can be used as the second electrode 1. As a method of supporting carbon on an electrode, there is a method of forming an ink using a resin and printing it on the support 3. By using carbon, it is possible to reduce the price of the electrode.

  The support 3 does not need to be transparent, and a substrate or a film that can reliably hold the second electrode 1 or the polymer electrolyte layer 4 can be used. As a material, a quartz glass plate, a white plate glass plate, or the like can be used. Glass substrates, glass epoxy substrates, ceramic substrates, paper substrates, and wood substrates can be used. In addition, the synthetic resin substrate that can be used is not limited to these, and esters such as polyethylene naphthalate and polyethylene terephthalate, cellulose esters such as polyamide, polycarbonate, and cellulose acetate, polyvinylidene fluoride, and polytetrafluoroethylene-cohexafluoropropylene. Examples include fluorine-based polymers such as polyether, polyethers such as polyoxymethylene, polyacetal, polyolefins such as polyethylene, polypropylene, methylpentene polymer and polystyrene, and polyimides such as polyimide-amide and polyetherimide. When these synthetic resins are used as the support 3, a flexible film-like structure can be used, but it is also possible to form a rigid substrate that does not easily bend.

  The TFT 2 formed in each pixel is selected by a wiring provided on the support 3 (not shown here) and controls the corresponding second electrode 1. The TFT 2 is extremely effective for preventing crosstalk between pixels. The TFT 2 is formed so as to occupy one corner of the second electrode 1, for example. However, the second electrode 1 may overlap the TFT 2 in the stacking direction, and in this case, the area can be used more effectively. Become. The TFT 2 may be provided on the common transparent electrode 5 side.

  As will be described later, the wiring is composed of each gate line for selecting the TFT 2 in each row and each data line for sending a data signal to the TFT 2 in each column. The gate electrode of each TFT 2 is connected to the gate line, one of the source and drain electrodes is connected to the data line, and the other is connected to the second electrode 1. The second electrode 1 forms a capacitor between the opposing common transparent electrode 5, and the common transparent electrode 5 forms a substantial ground potential. When a TFT 2 is selected from one row and turned ON by applying a signal to the gate line, a current for charging / discharging a capacitor corresponding to each pixel flows from each data line through the turned-on TFT 2, and data writing and erasing are performed. Done. The driving elements other than the TFT 2 are matrix driving circuits generally used for flat displays, and any driving elements can be used as long as they can be formed on the support 3 and are not particularly limited.

  As shown in FIG. 1, the polymer electrolyte layer 4 is held between the common transparent electrode 5 and the second electrode 1. The polymer electrolyte layer 4 contains at least a color variable material containing metal ions, a solvent, a supporting electrolyte, and a coloring material that colors this layer, with the polymer material as a base. In addition, at least a part of the color variable material and at least a part of the supporting electrolyte use different halogens as anion species.

  In this electrochemical display device, display information is written by reducing metal ions, which are constituents of the color variable material, on the common transparent electrode 5 and depositing metal fine particles on the common transparent electrode 5. Is called. In this case, the element can be observed from the support 6 side, and the aperture ratio is sufficient. On the contrary, the display information is erased by oxidizing the deposited metal and elution from the common transparent electrode 5. That is, electrochemical deposition, so-called electrolytic plating, and elution, which is the reverse reaction, are performed reversibly, and display information is written and erased.

  Although it does not specifically limit as said metal ion which can be discolored or decolored by such electrochemical reduction or oxidation, and precipitation or melt | dissolution accompanying this, It is preferable that silver ion is included. The reason why silver is suitable is that reversible reaction can be easily advanced and the degree of discoloration during precipitation is high.

For example, at the time of writing, silver ions are expressed by the following reaction formula: Ag ⁺ + e ⁻ → Ag
As shown in FIG. 2, a black precipitate 8 made of silver (Ag) fine particles is formed on the common transparent electrode 5. At the time of decoloring, the precipitated silver 8 is oxidized by a reverse reaction, changes to colorless silver ions (Ag ⁺ ) and dissolves again.

  The supporting electrolyte contained in the polymer electrolyte layer 4 preferably contains lithium ions. Lithium can impart high conductivity to the polymer electrolyte layer 4.

  Further, the different halogens are not particularly limited, but it is preferable that one of the different halogens is iodine, and that one of the different halogens is iodine and the other is bromine. preferable. The reason why iodine is preferable is that it bonds more strongly with silver ions than other halogens and forms a stable complex, that is, has good light resistance. In order to shorten the response time, generation of iodine due to a peroxidation state is inevitable. Therefore, the generation amount of iodine can be effectively suppressed by including bromine having an oxidation potential more noble than iodine as an ionic species. For example, in a system composed of a bromine ion species using AgBr as the color variable material and LiBr as the electrolyte, the reversibility of the reaction is poor and it cannot be used.

  Specifically, it is preferable that the color variable material is AgI and the electrolyte is LiBr. Alternatively, it is preferable that the color variable material is AgBr and the electrolyte is LiI. Further, the color variable material may be made of AgI and AgBr, and the electrolyte may be made of LiI and LiBr.

  The color variable material may contain metal ions other than silver ions, specifically, at least one metal ion selected from the group consisting of bismuth, copper, iron, chromium, nickel, and cadmium.

Furthermore, as the supporting electrolyte, besides, lithium salts such as LiCl, LiBr, LiI, LiBF ₄ , LiClO ₄ , LiPF ₆ , LiCF ₃ SO ₃ , potassium salts such as KCl, KI, KBr, sodium salts, For example, NaCl, NaI, NaBr, or tetraalkylammonium, tetrabutylammonium borofluoride, tetrabutylammonium perchlorate, tetrabutylammonium halide, or the like may be included. The alkyl chain lengths of the quaternary ammonium salts described above may be uneven.

  The concentration of the silver ions is preferably 0.5M or more and 2.0M or less, whereby the memory characteristics and response characteristics (especially low temperature) can be further improved. Among the above ranges, the range is more preferably 0.75 M or more and 1.0 M or less, whereby the memory characteristics and response characteristics (especially low temperature) can be more effectively improved.

  Moreover, it is preferable that the density | concentration of the said lithium ion is 1.3 times-1.5 times (molar ratio) of the density | concentration of the said silver ion.

  The electrochemical light control device according to the present invention has a higher silver ion concentration than the conventional device. In general technique such as plating, in order to carry out more precise plating, (1) raise the temperature of the plating bath, (2) raise the concentration of salt, (3) suitable additives (brightener, stress (4) Slowly plating at a low current density is performed. (4) Slow diffusion is performed so that the ion distribution in the bath is uniform. The electrochemical light control device of the present invention also uses a reversible plating reaction, and the above methods (1) to (5) should be applicable. However, (2) or (3) is applicable as the light control device. Therefore, the present inventor has intensively studied and found that the reversible plating reaction can be more effectively performed by the above method (2), that is, without particularly using an additive by increasing the concentration of the salt. I found. Further, it is considered that dendrite generation due to irreversibility of the silver precipitation dissolution reaction can be suppressed by increasing the concentration of the salt, and according to this, it is possible to extend the life of the device.

As the matrix (matrix) polymer material used for the polymer electrolyte constituting the polymer electrolyte layer 4 containing metal ions, the skeleton units are-(C-C-O) _n -and-(C-C-N, respectively. ) _N- , or-(C-C-S) _n- , polyethylene oxide, polyethyleneimine, and polyethylene sulfide. These may be branched as a main chain structure. Polymethyl methacrylate, polyvinylidene fluoride, polyvinylidene fluoride chlorite, polycarbonate, polyamide, polyvinyl butyral, and the like are also preferable.

  The polymer material may be crosslinked in combination with an initiator, and the crosslinking method may be photocrosslinking or thermal crosslinking. Further, the matrix (matrix) polymer material can be obtained by polymerizing the initiator and the monomer with light or heat.

  When the polymer electrolyte layer 4 is formed, it is preferable to add a required solvent to the matrix polymer material. Preferred examples of the solvent include water, ethyl alcohol, isopropyl alcohol and mixtures thereof when the matrix polymer is hydrophilic, and propylene carbonate, dimethyl carbonate, ethylene carbonate, and γ-butyrolactone when hydrophobic. Acetonitrile, sulfolane, dimethoxyethane, ethyl alcohol, isopropyl alcohol, dimethylformamide, dimethyl sulfoxide, dimethylacetamide, n-methylpyrrolidone, nitromethane, pyridine, dipyridyl and mixtures thereof are preferred.

  The polymer electrolyte layer 4 contains a colorant in order to improve contrast. As described above, when the color of the metal ions is black, a white material having high concealment is introduced as the background color. As such a material, for example, coloring white particles are used, and as the white particles for coloring, titanium dioxide, calcium carbonate, silica, magnesium oxide, aluminum oxide, or the like can be used. In addition, coloring pigments can also be used.

  In the case of using inorganic particles, the mixing ratio of the colorant is preferably about 1 to 20% by weight, more preferably about 1 to 10% by weight, and further preferably about 5 to 10% by weight. Further, in the case of mixing a pigment-based colorant, it may be 10% by weight. This is because the coloring efficiency of the dye is much higher than that of the inorganic particles. Therefore, if the dye is electrochemically stable, contrast can be obtained even with a small amount. Usually, an oil-soluble dye is preferred as the pigment.

  Moreover, the polymer electrolyte layer 4 may use one or a plurality of additives as necessary. The additive controls the precipitation of the metal ions, and any type of additive can be used as long as it achieves its purpose.

  Furthermore, the polymer electrolyte layer 4 may be gelled. As the gelation method, any of commonly used methods such as a method of curing the resin in the polymer electrolyte layer 4 by UV irradiation or heating, a method of physically reducing fluidity, and the like are applied. Is possible.

  The film thickness of the polymer electrolyte layer 4 is preferably 5 μm to 200 μm, more preferably 5 μm to 150 μm, and still more preferably 10 μm to 150 μm. The thinner the film thickness, the smaller the resistance between the electrodes, which is preferable because it leads to shortening of the color change and decoloring time and power consumption. However, when the thickness is less than 5 μm, the mechanical strength is lowered, and pinholes and cracks are likely to occur, which is not preferable.

  In order to hold the support 3 having the second electrode 1 and TFT 2, the polymer electrolyte layer 4, and the transparent electrode support 6 having the common transparent electrode 5, this electrochemical display device is shown in FIG. Thus, the sealing member 7 is attached to the periphery. The sealing member 7 securely holds both the supports 3 and 6 and the second electrode 1, the TFT 2, the polymer electrolyte layer 4, and the common transparent electrode 5 disposed therebetween.

  According to the above-described structure, in the electrochemical display device of the present embodiment, the TFT 2 can be used for matrix driving, and the black metal precipitate and background generated from the metal ions contained in the polymer electrolyte layer 4 With the white inorganic pigment that forms, display with high black density and contrast can be realized.

  In addition, since at least a part of the color variable material and at least a part of the supporting electrolyte use different halogens as anion species, as compared with the conventional example described above, only iodine is used as the anion species. Thus, the amount of iodine generated in the over-erased state after the dissolution reaction of the color variable material can be greatly reduced.

  Accordingly, when depositing the color variable material, it is possible to reduce the consumption of a part of the current for the reduction reaction of iodine as in the conventional example, so that the desired amount of the color variable material can be easily obtained. It can be deposited, and the display characteristics as a device can be improved. In addition, since the deposited color variable material can be reduced from being oxidized and eluted by iodine, the memory characteristics of the device can be improved. Furthermore, by using different halogens as the anion species, it becomes possible to improve response characteristics particularly at low temperatures.

Second Embodiment The present embodiment relates to a method for manufacturing the electrochemical display device of the first embodiment described above.

  3 and 4 are schematic cross-sectional views showing an example of a method for producing an electrochemical light control device according to the present invention as an electrochemical display device in the order of steps.

  First, as shown in FIG. 3A, a second electrode 1 and a TFT (thin film transistor) 2 made of a palladium film or the like having a desired thickness are provided for each pixel on a support 3 made of a polyethylene terephthalate film or the like. A pattern is formed so that each second electrode 1 such as a palladium film divided in a matrix form one pixel. The TFT 2 can be formed using a known semiconductor manufacturing technique, and is formed for each pixel so that each pixel can be driven independently.

  Next, as shown in FIG. 3B, the polymer electrolyte layer 4 is formed. In advance, the color variable material and the supporting electrolyte are dissolved in a solvent such as dimethyl sulfoxide, and a polymer material such as polyethylene oxide, the colorant such as titanium dioxide as white inorganic fine particles, and a crosslinking agent are added thereto. Disperse uniformly. This mixture is applied onto the support 3 on which the second electrode 1 and the TFT 2 are formed, and the polymer electrolyte layer 4 is formed. As the coating method, doctor blades, bar coaters, screen printing, and other known methods can be used.

  On the other hand, in parallel with this, as shown in FIG. 3C, a common transparent electrode 5 such as an ITO film is formed on a transparent electrode support 6 such as a glass substrate. The ITO film is formed by a method such as vapor deposition or sputtering. Immediately after the formation of the common transparent electrode 5, the transparent electrode support 6 is pressure-bonded to the support 3 so that the common transparent electrode 5 is in close contact with the uncured polymer electrolyte layer 4, and is attached as shown in FIG. Combined.

  After this bonding, the polymer electrolyte layer 4 forms a cross-link between the polymer materials depending on whether the transparent electrode support 6 is irradiated with ultraviolet light or heated, and the polymer electrolyte layer 4 is gelled. . When the crosslinking is not performed, the polymer electrolyte layer 4 that has been gelled by drying under reduced pressure is formed between the support 3 and the transparent electrode support 6.

  And the sealing member 7 is attached to the edge part of bonding as shown in FIG.4 (e), and the electrochemical light control apparatus based on this invention as an electrochemical display apparatus is completed.

  In the present embodiment, although not shown, metal ions are introduced together with the electrolyte at the stage of preparing the polymer electrolyte layer 4. Therefore, the polymer electrolyte layer 4 and the color variable material are combined in a relatively simple process, and can be easily manufactured.

  Moreover, although the example by the vacuum bonding method was demonstrated as a preparation method of the polymer electrolyte layer 4, it can also produce, for example by pressure reduction injection | pouring.

Third Embodiment The electrochemical dimming device according to the present embodiment is an example in which a potential detection electrode independent of the common transparent electrode and the second electrode is formed as a third electrode. Each of these potential detection electrodes is disposed as a member electrically insulated from these electrodes in the same plane as the common transparent electrode on the transparent electrode support and the second electrode on the support. And is used to detect the potentials of the common transparent electrode and the second electrode.

  FIG. 5 is a plan view of the second electrode 1 side. On the support 3, the second electrode 1 and the TFT 2 as a driving element are formed for each pixel, and each pixel is arranged in a matrix. The potential detection electrode 11 for detecting the potential of the second electrode 1 is formed in a substantially cross-shaped pattern in the space between each pixel, and its end (shown by a black circle in the figure) has a thickness of about. The silver or aluminum electrode 12 is 1000 nm. The portion of the line connecting the end portions is a silver or aluminum linear wiring portion 13 having a width of about 1 μm. Since the potential detection electrode 11 is formed as an electrically insulated member in the same plane as the second electrode 1, the potential of the second electrode 1 can be accurately monitored. Therefore, the reaction occurring at the second electrode 1 can be detected. As the material of the potential detection electrode 11, it is preferable to select a stable metal material that does not spontaneously elute into the polymer electrolyte layer 4, and silver, platinum, chromium, aluminum, cobalt, palladium, and the like similar to the second electrode 1 are used. Can be selected. In addition, since the potential detection electrode 11 can be formed of the same material in the same plane as the second electrode 1, the potential detection electrode 11 and the second electrode 1 may be formed by patterning together.

  FIG. 6 is a plan view of the common transparent electrode 5 side. The potential detection electrode 15 is formed in an inverted π-shaped pattern on the transparent electrode support 6 on which the common transparent electrode 5 is formed. Since the potential detection electrode 15 is formed as an electrically insulated member in the same plane as the common transparent electrode 5, the potential of the common transparent electrode 5 can be accurately monitored. Therefore, the reaction occurring at the common transparent electrode 5 can be detected. As a material for the potential detection electrode 15, it is preferable to select a stable metal material that does not spontaneously elute into the polymer electrolyte layer 4, and silver, platinum, chromium, aluminum, cobalt, palladium, and the like similar to those of the second electrode 1. Can be selected.

  FIG. 7 is a configuration diagram showing a drive circuit of an electrochemical light control device including the potential detection electrode 11. Pixels including the TFTs 2 and the second electrodes 1 are arranged in a matrix. Each gate line 28 for selecting pixels in each row and each data for sending data signals to the pixels in each column on the support. Lines 29 and 29a are provided. The gate electrode of each TFT 2 is connected to the gate line 28, one of the source or drain electrodes is connected to the data lines 29 and 29 a, and the other is connected to the second electrode 1. A capacitor 9 is formed between the second electrode 1 and the common transparent electrode 5 facing each other, and the common transparent electrode 5 forms a substantial ground potential.

  Corresponding to the gate line 28 and the data lines 29 and 29a, a gate line driving circuit 24 and data line driving circuits 23 and 23a are provided, respectively, and predetermined gate lines 28 and data are determined by signals from the signal control unit 22. Lines 29 and 29a are selected. That is, when a TFT 2 in one row is selected and turned ON by applying a signal to the gate line 28, a current for charging / discharging the capacitor 9 of each pixel flows from each data line 29, 29a through the TFT 2 which is turned ON. Are written and erased. The potential detection electrode 11 is connected to the signal control unit 22, and the potential of the pixel portion can be monitored by a signal from the potential detection electrode 11. Based on the monitor signal using the potential detection electrode 11, further reaction can be stopped when sufficient precipitation or electrochemical reaction is performed.

  Hereinafter, the present invention will be specifically described based on examples.

Example 1
(Preparation of display electrode)
An ITO film planarly arranged at a pitch of 150 μm on a glass substrate having a thickness of 1.5 mm and 10 cm × 10 cm was produced by a known method. A lead portion connected to the drive circuit was formed from this substrate by a known method, and then the whole was placed in the electrodeposition tank.

(Second electrode)
On a polyethylene terephthalate film having a thickness of 0.5 mm and a size of 10 cm × 10 cm, silver (Ag) films having a thickness of 3000 mm are formed by sputtering on a plane with a pitch of 150 μm, and a TFT is formed by a known method. Produced.

(Preparation of empty cell)
After spraying about 10 glass beads with a center particle diameter of 50 μm per square millimeter on the TFT electrode produced as described above, UV curable resin is dispensed to the sealing portion around the common transparent electrode with a dispenser. The coating was installed. At this time, a part of the sealing portion opened as an injection port for injecting the polymer electrolyte in a later step. Then, the common transparent electrode and the second electrode were aligned and bonded, and UV irradiation was performed under reduced pressure to form an empty cell in which the two electrodes were fixed while maintaining a uniform gap of 50 μm.

(Polymer electrolyte preparation and injection)
Silver iodide (AgI) 0.5M as the color variable material and lithium bromide (LiI) 0.67M as the supporting electrolyte (see Table 1 below), dimethyl sulfoxide / γ- as the solvent It was dissolved in a mixed solution of butyrolactone (volume ratio 6/4) (the lithium ion concentration was about 1.3 times the silver ion concentration (molar ratio)). Further, triethanolamine: coumarin: marcaptobenzimidazole was added as an additive so as to be 2: 1: 1 (g / l).

Next, the electrolyte solution prepared above, polyethylene oxide having a molecular weight of 200,000 as a polymer material, and titanium dioxide (TiO ₂ ) as a white colorant are mixed in an electrolyte / polymer material / colorant by weight ratio. = 5/1/6 was added, and this was uniformly dispersed. Then, the peroxide as a crosslinking agent was added at a ratio of 2 to 5% by weight with respect to polyethylene oxide. Subsequently, it inject | poured under reduced pressure in the empty cell produced above, and sealed the inlet. This was heated and crosslinked at 70 to 100 ° C. for several minutes to 10 minutes to gel the polymer electrolyte, and an evaluation cell having an active matrix structure as shown in FIG. 8 was produced. Here, if possible, the polymerization may be performed without adding a crosslinking agent. FIG. 9 is a schematic cross-sectional view of an example of an electrochemical light control device having an active matrix structure formed by further forming the third electrode 35 as the above-described potential detection electrode.

Examples 2 to 17 and Comparative Examples As shown in Table 1 below, each of the color changeable materials and their concentrations, and the supporting electrolyte and its concentration were changed in the same manner as in Example 1 except for changing each of the evaluation materials. A cell was produced.

Response time evaluation (applied voltage and temperature dependent characteristics)
When the display element is driven and colored, the minimum writing density is set to optical density (OD) = 1. However, the reflectance is 10% according to the following formula (1).
Optical density = −log (reflectance / 100) (1)

  The response time was defined as the time from the uncolored state until reaching the optical density (OD) = 1. The necessary charge amount is the amount of charge required until OD = 1 (time integration amount of current value). This required charge amount is one of the parameters of power consumption, and a smaller value is considered to be more advantageous for the device.

  FIG. 10A is a graph showing the results of measuring the relationship between the applied voltage and the response time when the temperature is changed for the evaluation cell of the comparative example. FIG. 10B is a graph showing the results of measuring the relationship between the applied voltage and the required charge amount when the temperature is changed for the evaluation cell of the comparative example.

  Moreover, (a) of FIGS. 11-13 is a graph which respectively shows the relationship between the applied voltage and response time at 25 degreeC, 10 degreeC, and -10 degreeC about the cell for evaluation of Examples 2-5. (B) of FIGS. 11-13 is a graph which respectively shows the relationship between the applied voltage at the time of 25 degreeC, 10 degreeC, and -10 degreeC about the evaluation cell of Examples 2-5, and required electric charge.

  As is apparent from FIGS. 11 to 13, the electrochemical light control device according to the present invention as an electrochemical display device has at least a part of the color variable material and at least a part of the electrolyte containing different halogens. Since the anion species is used, the amount of charge required is slightly increased as compared with the comparative example shown in FIG. However, the lower the temperature, the higher the rate at which the response time becomes slower as the salt concentration increases.

  Regarding the compositions of Examples 2 to 5, the higher the salt concentration, the slower the response time at the same applied voltage, and the necessary charge amount increased.

  In addition, in the region where the applied voltage was 2 to 4 V, the response time was faster as the applied voltage was higher. Here, as seen also in the comparative example, there is a high possibility that the response time will be suddenly delayed when the voltage exceeds a certain voltage. However, according to the present invention, the voltage value at the boundary is higher than that in the comparative example. I understand that it is expensive. However, the higher the applied voltage, the worse the repeated cycle characteristics, so it is considered disadvantageous to apply a very high voltage substantially.

  Next, for each of the evaluation cells of Examples 2 to 5, Examples 9 to 12, and Examples 14 to 19, the relationship between the temperature when the applied voltage was 3 V and the response time was measured. The results are shown in FIGS.

  As is apparent from FIGS. 14 to 15, the evaluation cells of Examples 9 to 12 and Examples 14 to 17 have almost the same response time as those of Examples 2 to 5 having the same salt concentration. The value of was shown. Although not shown in the figure, the same tendency was observed for the required charge amount. Moreover, although Example 3 and Examples 18 and 19 are different in the composition of the salt material at the time of preparation, the concentrations of silver ions, lithium ions, iodine ions and bromine ions finally included as constituents are Both were the same, and the characteristics in this case were almost the same.

  Next, with respect to the evaluation cell of Example 3, when the amount of the additive (triethanolamine / coumarin / mercaptobenzimidazole) was changed, the temperature was changed (25 ° C., 10 ° C., −10 ° C. ), Changes in response time (a) and required charge amount (b) due to applied voltage were measured.

  Specifically, in Example 3, the amount of additive was 2: 1: 1 (g / l) (triethanolamine: coumarin: mercaptobenzimidazole), whereas in Example 20, 6: 3: 3 (g / l), and in Example 21, 10: 5: 5 (g / l). The results are shown in FIG. 16 (25 ° C.), FIG. 17 (10 ° C.), and FIG. 18 (−10 ° C.).

  As is apparent from FIGS. 16 to 18, the required charge amount tended to decrease as the amount of the additive increased. However, the difference became smaller as the temperature was higher and the applied voltage was higher. In addition, as the amount of the additive increased, in particular, as the temperature was higher and the applied voltage was lower, the response time tended to be slightly delayed. In addition, in the composition of 10: 5: 5 (g / l) according to Example 21, a white precipitate is generated and the composition is changed by storing the electrolyte over a long period of time or by storing at a low temperature of −20 ° C. or lower. There was a thing. From the above, it was found that the power consumption can be reduced by appropriately selecting the concentration of the additive to the optimum composition.

In evaluating and displaying the memory characteristics, writing was performed by applying a DC pulse having a width of 150 ms so that the reflectance in the black display state was about 8%. After application of the write waveform, the circuit was shut off and an open circuit state was evaluated to evaluate the phenomenon that the write density became thinner with time, that is, the behavior of decreasing the memory property. If the reflectance immediately after inputting the write waveform is R1, the time until the R1 increases by 5% is defined as the display memory time (this is about 10% reflectance for human eyes) It is because it is known from the visual experiment that when the thickness gradually decreases from the above state, the thinness is felt when the reflectance increases by about 5%.)

  In optical density measurement (reflectance measurement), a red laser was input at a right angle to the display element surface, and the reflected light was detected at a position deviated by 20 ° therefrom to obtain the reflectance (diffuse reflection test).

  FIG. 19A shows a measurement result of a decrease in memory property with respect to the evaluation cell of the comparative example. FIG. 19B is a measurement result of a decrease in memory property for the evaluation cell of Example 1.

  As is clear from FIGS. 19A and 19B, the evaluation cell of the comparative example clearly has severe cycle fluctuations, and the memory time is gradually shortened. In contrast, in the evaluation cell of Example 1, since at least a part of the color variable material and at least a part of the supporting electrolyte use different halogens as anion species, the cycle is significantly higher than that of the comparative example. The fluctuation was reduced and the memory characteristics were improved.

  Next, for the evaluation cells of Examples 2 to 4, the measurement of the decrease in memory properties was performed in the same manner as described above. The results are shown in FIGS. 20 (a), (b) and (c), respectively.

  As is clear from FIG. 20, since the evaluation cells of Examples 2 to 4 have a higher salt concentration than that of Example 1, not only the cycle fluctuation is more stable, but also the memory characteristics are further improved. In particular, Example 3 in FIG. 20B has a memory time of 10000 seconds or more (not shown, but estimated from the decay curve is about 15000 seconds), and Example 3 is most excellent in memory time and cycle stability. It is thought that there is.

  Furthermore, the memory time of the 10th cycle is shown in FIG. 21 about the evaluation cell of Examples 1-4, Examples 8-11, and Examples 13-16. The concentration ratio of AgI / LiBr in Examples 1 to 4 is 3/4, the concentration ratio of AgI / LiBr in Examples 8 to 11 is 3/4, and the concentration ratio of AgI / LiBr in Examples 13 to 16 is 2 / 3.

As is clear from FIG. 21, it was found that when the silver ions as a whole have the same concentration, the memory time hardly changes even if the concentrations of lithium ions, iodine ions and bromine ions are somewhat different. Further, among Examples 1-4, Examples 8-11, and Examples 13-16, when the silver ion concentration [Ag ⁺ ] is 0.75 M or more and 1.0 M or less as the preparation concentration, the memory time is the longest. It turns out that is long.

With respect to the repeated cycle life , based on the above evaluation results, the response speed, its temperature dependence, the memory time and the like were mutually considered, and the repeated cycle characteristics of Example 3 which is the most excellent composition were evaluated.

  FIG. 22 is a graph showing an outline of a repetitive waveform. FIG. 23A is a graph showing display characteristics for each cycle. FIG. 23B is a graph showing the respective reflectivities at the time of white display and black display of the result shown in FIG.

  As is clear from FIG. 23, the electrochemical light control device according to the present invention as an electrochemical display device was able to operate extremely stably for about 200,000 cycles.

  As is clear from the above, in the electrochemical light control device according to the present invention as an electrochemical display device, at least a part of the color variable material and at least a part of the electrolyte use different halogens as anion species. Therefore, compared with the case where only iodine is used as an anionic species, for example, the generation amount of iodine in the over-erased state can be greatly reduced after the dissolution reaction of the color variable material.

  As a result, when the color variable material is deposited, it is possible to reduce the consumption of a part of the current for the reduction reaction of iodine, so that the desired amount of the color variable material can be easily deposited. The display characteristics as a device could be improved. In addition, since the deposited color variable material can be reduced from being oxidized and eluted by iodine, the memory characteristics of the device can be improved. Furthermore, by using different halogens as anionic species, it has become possible to improve response characteristics particularly at low temperatures.

  While the present invention has been described with reference to the embodiments and examples, the above examples can be variously modified based on the technical idea of the present invention.

  For example, the material, shape, and the like of the cell component including each electrode may be variously changed. The color variable material is not limited to metal ions, and other known materials can be used, and the color of the precipitate and the color variable material may be other than black.

  In addition, the electrochemical light control device according to the present invention can be applied to an optical shutter, an optical communication device, etc. by utilizing the light control function of the reflected or transmitted light amount as well as being configured as an electrochemical display device. is there. The electrochemical display device may have a single display area or may be divided into a plurality of pixel areas, and information to be displayed may be characters, symbols, or images. The display color may be any of mono color, multi color, and full color. For example, the display color may be obtained by dividing each pixel of the trio pixel as a cell.

It is a fragmentary perspective view of the electrochemical light control device based on this invention in embodiment of this invention. It is a schematic sectional drawing of the electrochemical light control device based on this invention. It is a schematic sectional drawing of an example of the manufacturing method of an electrochemical light control apparatus same as the above. It is a schematic sectional drawing of an example of the manufacturing method of an electrochemical light control apparatus same as the above. It is a top view by the side of the transparent pixel electrode of the electrochemical light control device based on this invention. It is a top view by the side of the common electrode of the electrochemical light control device based on this invention. 1 is a circuit diagram of an electrochemical light control device according to the present invention. FIG. It is a schematic sectional drawing of an example electrochemical dimmer based on this invention. It is a schematic sectional drawing of the electrochemical dimming device of the other example based on this invention equally. It is a graph which shows the relationship between the applied voltage of a comparative example (using only an iodine ion as anion seed | species) and a response time, and a temperature dependence characteristic by the Example of this invention. It is a graph which shows the relationship between the applied voltage at the time of 25 degreeC, response time (a), and required charge amount (b) similarly. It is a graph which shows the relationship between the applied voltage at the time of 10 degreeC, response time (a), and required electric charge (b) at the same. It is a graph which shows the relationship between the applied voltage at the time of -10 degreeC, response time (a), and required electric charge (b) similarly. It is a graph which shows the relationship between temperature and response time similarly. It is a graph which shows the relationship between temperature and response time similarly. It is a graph which shows the relationship between the applied voltage at the time of 25 degreeC, response time (a), and required charge amount (b) similarly. It is a graph which shows the relationship between the applied voltage at the time of 10 degreeC, response time (a), and required electric charge (b) at the same. It is a graph which shows the relationship between the applied voltage at the time of -10 degreeC, response time (a), and required electric charge (b) similarly. It is a graph which shows the result of memory characteristic evaluation similarly. It is a graph which shows the result of memory characteristic evaluation similarly. 3 is a graph showing the relationship between silver ion concentration and memory time. It is a graph which shows the outline of a repetitive waveform similarly. It is a graph which shows the display characteristic for every cycle, and each reflectance at the time of white display and black display.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 2nd electrode, 2 ... TFT, 3 ... Support body, 4 ... Polymer electrolyte layer, 5 ... Common transparent electrode,
6 ... Transparent electrode support, 7 ... Sealing member, 8 ... Metal deposit, 11, 15 ... Potential detection electrode,
12 ... Silver or aluminum electrode, 13 ... Silver or aluminum linear wiring part,
22 ... signal control unit, 23, 23a ... data line driving circuit, 24 ... gate line driving circuit,
28 ... Gate line, 29, 29a ... Data line, 31 ... Transparent electrode, 35 ... Third electrode

Claims (10)

A polymer electrolyte layer containing a color variable material that changes color or loses color by electrochemical reduction or oxidation and accompanying precipitation or dissolution, an electrolyte, and a polymer compound is formed between the first electrode and the second electrode. When manufacturing an electrochemical dimming device sandwiched between, wherein at least a part of the color variable material and at least a part of the electrolyte have different halogens as anionic species ,
And AgI and AgBr to be the color variable material, the electrolyte and LiI and LiBr made, the mixture of the polymer compound is supplied between the second pole and the first pole, the high molecular electrolyte layer Having a step of forming
Manufacturing method of electrochemical light control device . The method for producing an electrochemical light control device according to claim 1, wherein the polymer electrolyte layer is gelled. The polymer electrolyte layer concentration of silver ions of 0.5M or more of, you than 2.0 M, method for producing an electrochemical light control device described in claim 1. Wherein the concentration of silver ions 0.75M or more, it shall be the following 1.0 M, method for producing an electrochemical light control device described in claim 3. Wherein you 1.3 times to 1.5 times the concentration of silver ions in the concentration of lithium ions of the polyelectrolyte layers in the polymer electrolyte layer and (molar ratio), electrochemical tone of claim 1 Manufacturing method of optical device. It contains a color variable material that changes color or decolors by electrochemical reduction or oxidation and accompanying precipitation or dissolution, an electrolyte, and a polymer compound, and includes at least a part of the color variable material and at least one of the electrolyte. When producing a polymer electrolyte for an electrochemical light control device, wherein the part uses halogens different from each other as anion species ,
A step of preparing a mixture of AgI and AgBr serving as the color variable material, LiI and LiBr serving as the electrolyte, and the polymer compound;
A method for producing a polymer electrolyte for an electrochemical light control device . The manufacturing method of the polymer electrolyte of Claim 6 which has a gelatinization process. The concentration of silver ions of 0.5M or more, shall be the following 2.0 M, method for producing a polymer electrolyte according to claim 6. The silver ion concentration 0.75M or more, shall be the following 1.0 M, method for producing a polymer electrolyte according to claim 8. The concentration of lithium ion 1.3 to 1.5 times the concentration of silver ions (molar ratio), method for producing a polymer electrolyte according to claim 6.

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