JP6696287B2 - Driving method of electrochromic device and electrochromic device - Google Patents

Description

  The present invention relates to a driving method of an electrochromic device and an electrochromic device.

  In recent years, electronic paper and the like have been actively developed as an information medium that replaces paper. As a display device used for electronic paper, a display device (electrochromic element) utilizing an electrochromism phenomenon is known. The electrochromism phenomenon is a reversible phenomenon in which a voltage is applied to an electrochromic compound to cause the compound to undergo an oxidation-reduction reaction to develop or decolor.

  Electrochromic devices are expected to be the next-generation display devices because they can be made transmissive or reflective without using color filters or liquid crystals, have a memory effect, and can be driven at low voltage. Is performed (for example, see Patent Documents 1 and 2).

  The response speed of coloring and erasing is important for high-definition information display. However, in Patent Document 1, there is a change over time in coloring the coloring and erasing substance and a delay in the erasing speed after coloring for a long time. A method of driving an electrochromic device is disclosed, in which a voltage value during color development and a voltage value during color erasing are appropriately controlled and applied in order to suppress and improve the device life.

  In addition, the electrochromic device is expected to be a multicolor display device because it can emit various colors depending on the structure of the electrochromic compound. In Patent Document 2, in order to facilitate full-colorization and improve memory property, response speed, coloring efficiency, durability, etc., an electrochromic film is formed between a pair of transparent electrodes on which a semiconductor nanoporous layer is formed. There is disclosed a multicolor display device in which a plurality of structural units sandwiching an electrolyte layer containing is laminated.

  In electrochromic devices, the color development state from color development to decolorization is not constant and decreases in the direction of color fading over time.Therefore, it is necessary to keep the color development state constant. The conditions necessary for the above change depending on the characteristics of the device, the coloring level to be retained, the usage environment, and the like.

  However, in the above-mentioned conventional technique, there is no disclosure about a technique for changing the driving condition in accordance with the characteristics of the electrochromic element and the like to keep the coloring state constant.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to maintain a color-developed state at a predetermined color-developing level and to easily perform decolorization.

In order to achieve the above-mentioned object, a driving method of an electrochromic device according to the present application includes a first electrode, a second electrode facing the first electrode with a space, and two electrodes. An electrochromic device for driving an electrochromic device comprising an electrolyte provided between the electrochromic compound and the electrochromic compound or the electrochromic composition, the electrochromic layer being formed on the surface of at least one of the two electrodes. A driving method, in which a voltage is applied between the first electrode and the second electrode to cause the electrochromic layer to develop color, and then the opening between the first electrode and the second electrode is performed. When the voltage is measured and the elapsed time from the application of the voltage for color development is t, the open circuit voltage measured at the elapsed time t is V, and the constants are A and B, the following formula (1)
(1) V = A * Ln (t) + B
Based on the above, the open circuit voltage at which the absolute value of the open circuit voltage or the time change of the open circuit voltage after the lapse of a predetermined period during which the open circuit voltage stabilizes is equal to or less than a threshold value is calculated, and the open circuit voltage between the first electrode and the second electrode is calculated. In addition, the calculated voltage calculated based on the equation (1) is applied.

  According to the present invention, it is possible to maintain a coloring state at a predetermined coloring level. Further, it is possible to provide a driving method of an electrochromic device capable of easily decoloring.

It is sectional drawing which showed typically one structural example of the electrochromic element of the 1st Embodiment which concerns on this invention. 3 is a flowchart showing drive control of the electrochromic device of the first embodiment. 7 is a flowchart showing drive control in the electrochromic device according to the first embodiment in the case of continuously applying a calculated voltage as a holding drive. 6 is a flowchart showing drive control in the case of performing pulse application of a calculation voltage as holding drive in the electrochromic device of the first embodiment. 6 is a flow chart showing drive control in the electrochromic device of the first embodiment in the case of determining whether to perform pulse application of a calculated voltage or hold an open state based on the difference between the calculated voltage and the open voltage as the holding drive. It is sectional drawing which showed typically one structural example of the electrochromic element of the 2nd Embodiment which concerns on this invention.

(First embodiment)
<Structure of electrochromic device>
Hereinafter, the electrochromic device according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing the configuration of the electrochromic device 100 according to the first embodiment.

  As shown in FIG. 1, the electrochromic device 100 of the present embodiment includes a display substrate 10, a display electrode (first electrode) 11 formed on the display substrate 10, and an electrochromic device provided in contact with the display electrode 11. The chromic layer 12, the counter substrate 14 provided so as to face the display substrate 10, the counter electrode (second electrode) 13 formed on the counter substrate 14, and the display electrode 11 and the counter electrode 13 are sandwiched. The electrolyte 15, the spacer 16, and the driving means 17 are provided.

[Display substrate 10, counter substrate 14]
The display substrate 10 and the counter substrate 14 are bonded to each other with a spacer 16 interposed therebetween, and have a cell structure. The display substrate 10 supports the display electrode 11 and the electrochromic layer 12, and the counter substrate 14 supports the counter electrode 13.

  At least one of the combination of the display substrate 10 and the display electrode 11 and the combination of the counter substrate 14 and the counter electrode 13 is preferably transparent. Also, the combination of both may be transparent. By making it transparent, it is possible to further improve the visibility of the color generated by the electrochromic layer 12.

  Examples of the material forming the display substrate 10 and the counter substrate 14 include glass and plastic. When a plastic film is used as the display substrate 10 and the counter substrate 14, a lightweight and flexible electrochromic device 100 can be manufactured.

[Display electrode 11, counter electrode 13]
The display electrode 11 is an electrode for controlling the potential with respect to the counter electrode 13 and causing the electrochromic layer 12 to develop a color. The counter electrode 13 is an electrode for controlling the potential of the display electrode 11 with respect to the counter electrode 13 and causing the electrochromic layer 12 to develop a color.

  The material forming the transparent electrode of the display electrode 11 and the counter electrode 13 is not particularly limited as long as it is a material having conductivity, but since it is necessary to ensure light transmission, it is transparent and conductive. A transparent conductive material having excellent properties is used. As a result, the visibility of the color developed by the electrochromic layer 12 can be further enhanced.

  Examples of the transparent conductive material include indium oxide doped with tin (hereinafter referred to as “ITO”), tin oxide doped with fluorine (hereinafter referred to as “FTO”), tin oxide doped with antimony (hereinafter referred to as “ATO”), and the like. Inorganic materials can be used. Among these, indium oxide (hereinafter referred to as “In oxide”), tin oxide (hereinafter referred to as “Sn oxide”) or zinc oxide (hereinafter referred to as “Zn oxidation”) formed by vacuum film formation are particularly preferable. It is preferable that it is an inorganic material containing any one of the above.

In oxide, Sn oxide, and Zn oxide are materials that can be easily formed into a film by a sputtering method, and also have good transparency and electric conductivity. Further, particularly preferable materials include InSnO, GaZnO, SnO, In ₂ O ₃ and ZnO.

  When vacuum film formation is used, the film thickness is preferably 20 nm to 500 nm, more preferably 50 nm to 200 nm, and it is possible to achieve both conductivity and transparency.

  As the conductive material, a transparent silver Ag, gold Au, copper Cu, carbon nanotube CNT, a network electrode of a metal oxide, or a composite layer thereof is also useful. The network electrode is an electrode in which carbon nanotubes or other non-permeable material having high conductivity is formed into a fine network to have a transmittance.

  Furthermore, it is also preferable that the electrode layer has a laminated structure of a network electrode and a conductive oxide. By forming the display electrode 11 and the counter electrode 13 in such a laminated structure, the electrochromic layer 12 can be colored and erased uniformly.

  The material of the display electrode 11 or the counter electrode 13 which does not require transparency may include a metal material. For example, platinum Pt, silver Ag, copper Cu, gold Au, chromium Cr, rhodium Rh, alloys thereof, or a laminated structure of these may be used. Examples of the manufacturing method include a vacuum vapor deposition method, a sputtering method, an ion plating method and the like.

[Electrochromic layer 12]
The electrochromic layer 12 is a layer containing an electrochromic compound or an electrochromic composition. The electrochromic layer 12 can also be configured to include a metal oxide carrying an electrochromic compound. The electrochromic compound or electrochromic composition causes a color change (color development) by an oxidation reaction or a reduction reaction. The metal oxide is for supporting an electrochromic compound and for developing and decoloring at high speed.

  Examples of the metal oxide include nanoparticles such as titanium oxide. By adsorbing a single molecule of the electrochromic compound, electrons can be efficiently injected into the electrochromic compound by utilizing the large surface area of the metal oxide nanoparticles. Therefore, the color density of the electrochromic layer 12 at the time of color development can be increased, and the speed of switching between color development and decolorization can be increased.

  As the electrochromic compound, for example, known electrochromic compounds such as polymer type, dye type, metal complex and metal oxide are used.

  Specific examples of the polymer-based and dye-based electrochromic compounds include azobenzene-based, anthraquinone-based, diarylethene-based, dihydroprene-based, styryl-based, styrylspiropyran-based, spirooxazine-based, spirothiopyran-based, thioindigo-based, and tetrathiafulvalene. System, terephthalic acid system, triphenylmethane system, triphenylamine system, naphthopyran system, viologen system, pyrazoline system, phenazine system, phenylenediamine system, phenoxazine system, phenothiazine system, phthalocyanine system, fluorane system, flugide system, benzopyran system , Low-molecular-weight organic electrochromic compounds such as metallocene compounds, and conductive polymer compounds such as polyaniline and polythiophene are used.

Among the above, it is particularly preferable to include a dipyridine compound represented by the following general formula (a). Since these materials have a low coloring and decoloring potential, even when the electrochromic element 100 having a plurality of display electrodes is constructed, a favorable coloring color value is exhibited due to the reduction potential.

In the general formula (a), R1 and R2 each independently represent an alkyl group having 1 to 4 carbon atoms which may have a substituent or an aryl group, and at least one of R1 and R2 is COOH or PO. It has one group selected from (OH) ₂ and Si (OC _k H _{2k + 1} ) ₃ . X represents a monovalent anion. n represents 0, 1 or 2. A represents an alkyl group having 1 to 20 carbon atoms, an aryl group or a heterocyclic group which may have a substituent.

[Electrolyte 15]
The electrolyte 15 is for transferring charges as ions between the display electrode 11 and the counter electrode 13 to cause the electrochromic layer 12 to develop color. The electrolyte 15 can be supported on a polymer, and by patterning the polymer, it is possible to easily form a coloring and decoloring region (that is, a pixel).

  As the electrolyte 15, an electrolytic solution in which a supporting salt is dissolved in a solvent is generally used. Therefore, the ionic conductivity is high. As the supporting salt, for example, an inorganic ionic salt such as an alkali metal salt or an alkaline earth metal salt, a quaternary ammonium salt, an acid or an alkali supporting salt can be used.

Specifically, LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ COO, KCl, NaClO ₃ , NaCl, NaBF ₄ , NaSCN, KBF ₄ , Mg (ClO ₄ ) ₂ , Mg ( BF ₄ ) ₂ , tetrabutylammonium perchlorate, etc. can be used.

  Examples of the solvent include propylene carbonate, acetonitrile, γ-butyrolactone, ethylene carbonate, sulfolane, dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,2-dimethoxyethane, 1,2-ethoxymethoxyethane, polyethylene. Glycol, alcohols and the like can be used.

  Further, as the electrolyte 15, an ionic liquid which is a non-volatile material can also be used. The ionic liquid is not particularly limited, and any substance generally studied and reported may be used. Ionic liquids have a molecular structure that shows liquids in a wide temperature range including room temperature.

  The molecular structure of an ionic liquid consists of a cation component and an anion component. Examples of the cation component include imidazole derivatives such as N, N-dimethylimidazole salt, N, N-methylethylimidazole salt and N, N-methylpropylimidazole salt; N, N-dimethylpyridinium salt, N, N-methyl. Aromatic salts such as pyridinium derivatives such as propylpyridinium salt; aliphatic quaternary ammonium compounds such as tetraalkylammonium such as trimethylpropylammonium salt, trimethylhexylammonium salt, triethylhexylammonium salt and the like.

Further, as the anion component, a compound containing fluorine is preferable from the viewpoint of stability in the atmosphere, and examples thereof include BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , PF ₄ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , B. (CN ₄₎ ^-, and the like. Ionic liquids formulated by combining these cation components and anion components can be used.

  Further, as the electrolyte 15, an ionic substance such as an electrolytic solution or an ionic liquid cured with a resin or the like can be used. Such electrolyte 15 is highly safe because it can prevent liquid leakage from the element. Examples of the curable resin include common materials such as acrylic resin, urethane resin, epoxy resin, vinyl chloride resin, ethylene resin, melamine resin, photocurable resin such as phenol resin, and thermosetting resin. However, a material having high compatibility with the electrolyte is preferable.

  As such a structure, a derivative of ethylene glycol such as polyethylene glycol or polypropylene glycol is preferable. Further, it is preferable to use a photocurable resin as the curable resin. This is because the element can be manufactured at a low temperature and in a short time as compared with a method of forming a thin film by thermal polymerization or evaporating a solvent.

  A particularly preferred combination is an electrolyte layer composed of a solid solution of a matrix polymer containing an oxyethylene chain or an oxypropylene chain and an ionic liquid. By using this structure as the electrolyte 15, it is easy to achieve both hardness and high ionic conductivity.

[Driving means 17]
The driving means 17 is connected to the display electrode 11 and the counter electrode 13 by a conducting wire 18, respectively, and controls the amount of charge applied between the display electrode 11 and the counter electrode 13 to cause the electrochromic layer 12 to undergo a redox reaction. It has the function of developing and erasing colors. That is, the driving unit 17 can control the potential of the display electrode 11 with respect to the counter electrode 13 to cause the electrochromic layer 12 provided on the display electrode 11 to develop and erase color.

  In addition, the driving unit 17 applies a predetermined voltage between the display electrode 11 and the counter electrode 13 to perform color driving, and then measures the open circuit voltage of the electrochromic device 100 for a predetermined period or more, and the measured open circuit voltage. And the time, the constants A and B of the following relational expression (1) are obtained. The constants A and B whose time changes of the constants A and B are stable with respect to time are adopted as the constants A and B of the relational expression (1). Based on the relational expression (1) using the constants A and B, the open circuit voltage after the lapse of a predetermined period during which the open circuit voltage stabilizes or the absolute value of the time change of the open circuit voltage is equal to or less than the threshold value is calculated.

(1) V = A * Ln (t) + B

  In the above relational expression (1), t is the elapsed time from the application of the voltage for color development (color drive), V is the open circuit voltage measured at the elapsed time t, and A and B are constants.

  The driving unit 17 performs the color-holding drive by applying the calculated voltage between the display electrode 11 and the counter electrode 13 after the color-developing drive. The open circuit voltage means the voltage between both terminals when the output terminal is opened.

  The drive unit 17 can be configured to include, for example, a CPU, a ROM, a main memory, and the like. Various functions of the driving unit 17 can be realized by reading a program recorded in the ROM or the like into the main memory and executing the program by the CPU. However, some or all of the driving means 17 can be realized only by hardware. Further, the driving means 17 may be physically composed of a plurality of devices.

<Driving Method of Electrochromic Element 100>
A driving method (driving control) of the electrochromic device 100 according to the present embodiment will be described based on the flowchart of FIG. First, the initial state before the erasing process is set to the decoloring state (step S1). Next, the driving unit 17 applies a predetermined voltage between the display electrode 11 and the counter electrode 13 to drive color development (step S2), and the electrochromic element 100 is caused to develop a color state (step S2). S3). Then, the open circuit voltage of the electrochromic device 100 is measured (step S4). While measuring, the values of the constants A and B are sequentially calculated based on the relational expression (1), and the constants A and B when the time change of the constants A and B is stable are used to calculate the voltage ( In 1), the open circuit voltage after the lapse of a predetermined period during which the open circuit voltage stabilizes or the absolute value of the time change of the open circuit voltage is equal to or less than the threshold value is calculated (step S5). The calculated voltage is applied between the display electrode 11 and the counter electrode 13 by the driving means 17 (step 6). After that, a predetermined voltage is applied to drive the color erasing (step S7), and the color is erased (step S8).

  As a modified example of the driving method, a driving method (driving control) in the case where the application of the calculated voltage of FIG. 2 (step S6) is continuously applied will be described with reference to the flowchart of FIG. As described above, the difference from FIG. 2 is whether the calculation voltage is simply applied (step S6 in FIG. 2) or continuously applied (step S6A in FIG. 3). When the color is held, it is better to retain the color state by applying the calculated voltage as in step S6 of FIG. 2 than when nothing is applied after the color is developed, but the calculated voltage is applied only once. As in the case of not doing it, the color disappears over time. On the other hand, in step S6A of FIG. 3, the calculated voltage is continuously applied for a desired time in which the colored state is desired to be maintained. Thereby, the voltage between the electrodes is kept constant, and the color development is easily stabilized.

  As another different modification, a drive method (drive control) in the case where the calculation voltage application (step S6A) in FIG. 3 is pulsed will be described with reference to the flowchart in FIG. The difference from FIG. 3 is that, as described above, when the calculation voltage is applied in the period in which the color development is desired to be maintained, it is not applied continuously with the calculation voltage (step S6A in FIG. 3) but is applied using a pulse ( That is, step S6B in FIG. By performing pulse application as in step S6B of FIG. 4 instead of continuous application, it is possible to expect reduction in power consumption in holding drive and adjustment of holding drive by changing the duty ratio. When the duty ratio is close to 1 and is large, it is close to the continuous application in FIG. 3 and the expected effect is weakened by using the pulse. Although the degree varies depending on the sample, when the duty ratio becomes low, it approaches that in FIG. 2, that is, when the open period is long, the color development is not retained.

  As another different modification to the above-described FIG. 4 in which the calculation voltage is pulse-applied (step S6B in FIG. 4), driving is performed in which the application timing of the calculation voltage reflects the open circuit voltage change of the electrochromic element 100. The method (drive control) will be described based on the flowchart of FIG. 4 is different from FIG. 4 in that after the voltage V1 used for holding drive is calculated (step S5C in FIG. 5), the open circuit voltage V2 that changes with time is measured (step S6-1 in FIG. 5), and the calculated voltage V1 The above-mentioned open circuit voltage V2 is compared (| V1 | − | V2 |) (step S6-2 in FIG. 5), and when the value is equal to or more than the threshold value, that is, the open circuit voltage V2 is smaller than the calculated voltage V1 (color erasing). Direction) (| V1 | ≧ | V2 |) and the difference is large, the calculated voltage V1 is applied (step S6-3 in FIG. 5). If not (| V1 | <| V2 | or | V1 |-| V2 | is less than the threshold value), it is determined that the calculation voltage need not be applied, and step S6-3 is not performed.

  In either case, the process proceeds to step S6-4 as holding drive, and the desired color development holding time t0 is compared with the elapsed time ts3 after step S3 (coloring state) until the desired time elapses (while ts3 <t0). The procedure returns to the measurement of the open circuit voltage V2 (step S6-1). After the desired time has elapsed (ts3 ≧ t0), the process proceeds to the decoloring drive (step S7). These (steps S6-1 to S6-4) are collectively referred to as holding drive (pulse application of a calculation voltage that reflects an open circuit voltage change) (step S6C). Since the holding drive (step S6C) in FIG. 5 needs to describe the determination therein, the holding drive end determination (step S6-4) is described. However, step S6 ends and step S7 ends. In order to indicate that the process shifts to, each step S6, S6A, S6B in the flow before FIG. 4 may include a similar end determination. The calculation voltage may be applied for any time as long as it falls within a desired time period, but it is desirable that the calculation voltage is not longer than the open state before the calculation voltage is applied.

  It should be noted that the above driving methods are merely examples, and the driving methods are not necessarily limited to these. For example, when it is desired to obtain only the open circuit voltage by calculation, step S6 in FIG. 2 may be omitted. If the calculation voltage is applied to improve the stability of the electrochromic device 100, the continuous application of FIG. 3 and the pulse application of FIG. 4 may be combined, or may be applied based on the determination of FIG.

  Here, the effectiveness of the open circuit voltage in the holding drive will be described. When the electrochromic element is colored by being oxidized or reduced, the open circuit voltage of the electrochromic element is different from the stable state of decolorization. Here, an electrochromic device that is stable in decolorization will be described. When voltage, current, pressing force, etc. are not applied to the electrochromic element from the outside and the environment surrounding the electrochromic element, that is, light, temperature, humidity, pressure (atmospheric pressure, water pressure) is constant, it takes a long time. On the other hand, the electrochromic element is in the decolored state, and the open circuit voltage has a constant value. The value varies depending on the above-mentioned environment and also changes according to the redox state of the electrochromic element, that is, the optical characteristic state.

  For example, by applying a voltage or current to the electrochromic element that is decolorized to cause an oxidation-reduction reaction, it is possible to perform color development driving that obtains a colored state, and by performing a reverse reaction, it is possible to perform decolorization driving that obtains a decolored state. However, the color-developed state is unstable in the sample (electrochromic layer) in the stable state of decolorization, and the color-degradation state goes toward the decolored state with the lapse of time without actively performing the decolorization drive. At this time, the open-circuit voltage of the electrochromic element also changes from the above decolorization stable state due to color formation driving, and goes from that value to the decolorization stable state value. The change to the stable erasing state over time, that is, the coloring state is not constant from the start of erasing driving to the start of erasing driving, and the erasing direction decreases with lapse of time.

  The holding drive is a drive that is performed in order to keep the coloring state constant. The conditions required for the holding drive change depending on the characteristics of the electrochromic device, the color development level to be held, the environment, and the like. When the power to increase the color development is strong, the color development is dark, and when the color development is weak, the color is light. Therefore, the color development state cannot be kept constant, and it is necessary to appropriately determine the holding drive condition. Further, in the electrochromic element and the concentration thereof where the coloring state is stable even though it is not as much as the decoloring state, although the decoloring change with time is small, the decoloring state is less likely to occur, so that the coloring state is maintained. Rather than holding drive, holding drive is required to maintain the relationship between color forming drive and color erasing drive.

  Even in the case of holding drive using an open circuit voltage, the initial value varies depending on the coloring condition and the coloring level. For example, when the color density is changed by changing the application time, the voltage application at (V, t1) and the voltage application at (V, t2) are (V is an applied voltage, t1 and t2 are application times, and (t1> t2), the voltage is the same at the end of the voltage application for the color forming drive, but the open-circuit voltage after the end is different, and the time change speed is also different. It is effective to maintain the open circuit voltage by some means in order to keep the color development state constant, and it is necessary to determine the voltage when the method of holding drive is adopted.

  In the above, the example of decolorization stability was described, but excluding substances that develop color in a normal state called normally colored and that cause decoloration or further color development or hue change by oxidation or reduction. I haven't. That is, by oxidizing or reducing from the stable state, the predetermined state A and the state B having a color different from the state A change. Since either the state A or the state B is stable and either one is transparent, it is desirable to determine the driving condition of the holding drive even in the normally colored state. In addition, the same is true regardless of whether the states A and B are colored (not transparent).

  Therefore, in the driving method of the electrochromic element 100 according to the present embodiment, after the color development driving, the open circuit voltage after a predetermined period in which the open circuit voltage stabilizes or the open circuit voltage at which the absolute value of the time change of the open circuit voltage is equal to or less than the threshold value is set. It is possible to maintain the voltage according to each color development level by applying the calculated voltage, which is calculated from the change in open circuit voltage after color development using an approximate expression. Therefore, it is possible to suppress an increase in color development, a decrease in color development, and deterioration of the electrochromic element 100 due to the increase. Furthermore, since the open circuit voltage of the electrochromic device 100 is measured after color driving and the open circuit voltage is used, it is possible to cope with changes in the characteristics of the electrochromic device 100.

  Note that the open circuit voltage may be continuously applied for a predetermined period during the holding drive. This makes it possible to simplify the driving method of the electrochromic element 100 without requiring control during holding and driving.

  Further, during the holding drive, the open circuit voltage may be applied in a pulse shape for a predetermined period at predetermined pulse intervals. As a result, it is possible to suppress the influence of the holding drive on other than the color density. In addition, when a plurality of electrochromic devices 100 are operated, the holding drive operation can be sequentially performed. Further, by applying an alternating current such as a rectangular wave, a triangular wave, and a sine wave in a pulse shape, it is possible to suppress the influence at the time of rush.

  Further, when applying the open circuit voltage in pulses, the pulse interval may not be constant, but may be changed according to the time from the start of application of the open circuit voltage for holding drive. It is possible to easily hold the open circuit voltage by changing the pulse interval for the electrochromic device 100 in which the open circuit voltage greatly varies.

  In addition, the electrochromic device 100 of the first embodiment has a memory in which the optical characteristics are within a desired range during the time until the approximate expression is determined. Therefore, by applying a voltage, the inside of the electrochromic element 100 is maintained in an active state, and the fixation and reaction of the coloring state are prevented, so that it is possible to suppress the voltage increase and the time increase at the time of color erasing. In addition, since it is possible to suppress an increase in voltage during decoloring driving, it is possible to suppress deterioration of the electrochromic element 100. Further, it is possible to reduce the time required for the color erasing drive. This is the same for the decoloring of the sample in which the color development is within the allowable level range at the desired retention drive time, that is, the sample which does not require the retention drive for the purpose of retaining the color development, and suppresses the rise of the decolorization voltage. be able to.

(Second embodiment)
<Structure of electrochromic device>
Next, the electrochromic device of the second embodiment will be described with reference to the drawings. FIG. 6 is a sectional view schematically showing the configuration of the electrochromic element 200 of this embodiment. The electrochromic device 200 of the second embodiment is the same as the electrochromic device 100 of the first embodiment, except that a plurality of display electrodes 11, 21, 31 and electrochromic layers 12, 22, 32 are provided. It has a basic configuration. Therefore, the same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof may be omitted.

  As shown in FIG. 6, in the electrochromic device 200 according to the second embodiment, three display electrodes 11, 21, 31 facing the counter electrode 13 are provided separately from each other. Electrochromic layers 12, 22, 32 are provided corresponding to the respective display electrodes 11, 21, 31. An insulating layer 19 is provided between the electrochromic layer 12 and the display electrode 21, and an insulating layer 29 is provided between the electrochromic layer 22 and the display electrode 31.

  The display electrode 11 is an electrode for controlling the potential with respect to the counter electrode 13 and causing the electrochromic layer 12 to develop a color. The display electrode 21 is an electrode for controlling the potential with respect to the counter electrode 13 and causing the electrochromic layer 22 to develop a color. The display electrode 31 is an electrode for controlling the potential with respect to the counter electrode 13 and causing the electrochromic layer 32 to develop a color.

  The driving means 17 applies a voltage between each display electrode 11, 21, 31 and the counter electrode 13, and drives the electrochromic layers 12, 22, 32 corresponding to the display electrodes 11, 21, 31 to which the voltage is applied. Let the color fade.

  The electrochromic layers 12, 22, 32 can be configured to emit different colors. Further, the electrochromic layer 12 provided in contact with the display electrode 11, the electrochromic layer 22 provided in contact with the display electrode 21, and the electrochromic layer 32 provided in contact with the display electrode 31 are independently generated. Can be erased.

  That is, it is possible to color only the electrochromic layer 12, color only the electrochromic layer 22, and color only the electrochromic layer 32. Further, it is possible to perform color development by the two layers of electrochromic layer 12 and electrochromic layer 22, color development by the two layers of electrochromic layer 12 and electrochromic layer 32, and color development by the two layers of electrochromic layer 22 and electrochromic layer 32. .. Furthermore, color development is possible by the three layers of electrochromic layer 12, electrochromic layer 22, and electrochromic layer 32. As a result, multicolor display is possible.

  As described above, by providing a plurality of display electrodes, an electrochromic device compatible with multicolor display can be realized. In this embodiment, three display electrodes and three electrochromic layers are provided, but the present invention is not limited to this, and two display electrodes and four or more electrochromic layers may be provided.

<Driving Method of Electrochromic Element 200>
As the driving method (driving control) of the electrochromic element 200 according to this embodiment, the same driving method (driving control) as that of the electrochromic element 100 of the first embodiment shown in FIGS. 2 to 5 can be used. .. At this time, a voltage is applied between the display electrodes 11, 21 and 31 and the counter electrode 13 to drive the electrochromic layers 12, 22 and 32 to develop color, and while measuring the open circuit voltage respectively, A and B are measured. Is calculated one after another on the basis of the relational expression (1), and A and B when the time change of A and B is stable are adopted as the relational expression (1) to be used for voltage calculation. The open circuit voltage at which the absolute value of the open circuit voltage after the lapse of the period or the time change of the open circuit voltage is equal to or less than the threshold value is calculated. Each calculated voltage is applied individually to carry out holding drive. As described above, also in the second embodiment, the same effect as in the above-described first embodiment can be obtained during the holding drive. For the convenience of individual application, the continuous application of FIG. 3 is possible if only one of the electrochromic layers 12, 22, 32 is used. However, when sequentially applying each electrochromic layer 12, 22, 32, pulse application is performed. Alternatively, it is necessary to devise such as switching the continuous application of FIG. 3 for each electrochromic layer 12, 22, 32 as in the first embodiment.

  Note that the configuration and driving method of the electrochromic device capable of supporting multicolor display are not limited to the configuration and driving method of the electrochromic device 200 of the present embodiment. For example, voltages can be applied between the display electrode 11 and the counter electrode 13, between the display electrode 21 and the counter electrode 13, and between the display electrode 31 and the counter electrode 13 at different application times. Further, the display electrodes 11, 21, 31 and the electrochromic layers 12, 22, 32, etc. are not limited to the laminated structure as shown in FIG. 6, and may be arranged in parallel or irregularly. In that case, the limitation or device for the continuous application of FIG. 3 as described above is unnecessary.

(Example)
Examples of the electrochromic device and the driving method thereof according to the present invention will be described below.

  The electrochromic device used in the examples was manufactured by the following procedure. A glass substrate was prepared, and a display electrode 11 was formed by forming a transparent conductive thin film of indium oxide and tin oxide on the upper surface region by a sputtering method. By applying SP210 (trade name: manufactured by Showa Titanium Co., Ltd.) as a titanium oxide nanoparticle dispersion liquid on the glass substrate on which the display electrode 11 is formed by a spin coating method and performing an annealing treatment at 120 ° C. for 15 minutes, A titanium oxide particle film was formed.

  Next, a coating solution obtained by mixing a 2,2,3,3-tetrafluoropropanol solution of 5 wt% of a viologen compound and SP210 described above in a ratio of 2.4 / 4 was applied by a spin coating method, and at 120 ° C. By annealing for 10 minutes, titanium oxide particles and electrochromic compound [4,4 '-(1-phenyl-1H-pyrrole-2,5-diyl) bis (1- (4- (phosphonomethyl) benzyl) pyridinium ) bromide] was formed. Through the above steps, the display substrate 10 provided with the display electrode 11 and the electrochromic layer 12 was obtained.

  On the other hand, another glass substrate was prepared, and the counter electrode 13 was formed on the upper surface region of the display substrate 10 by depositing a transparent conductive thin film by a sputtering method. The counter electrode 13 was formed by forming two rectangular patterns in a stripe shape with L (line) / S (space) = 11 (mm) / 1 (mm).

  A coating liquid containing an arylamine compound was applied onto the glass substrate having the counter electrode 13 formed thereon by a spin coating method, and the obtained film was cured by a UV irradiation device for 60 seconds. Then, an annealing treatment was performed at 60 ° C. for 10 minutes to form a polymer layer in which a radically polymerizable compound having a triarylamine compound was polymerized. After that, trimming was carried out in the shape of the counter electrode 13 so that the polymer layer was formed only on the counter electrode 13. Through the above steps, the counter substrate 14 provided with the counter electrode 13 was obtained.

  Next, an electrolyte solution containing PEG400 (trade name: manufactured by Nippon Kayaku Co., Ltd.) was prepared, and the electrolyte solution was dropped on the prepared counter substrate 14. The display substrate 10 and the counter substrate 14 are arranged so as to face each other with their upper surfaces (the surfaces on which the display electrodes 11 and the counter electrodes 13 are formed) facing inward, and they are displaced so that an electrode lead-out portion can be formed via a spacer 16. Pasted together As a result, the electrochromic device 100 (FIG. 1) in which the electrolyte 15 was enclosed was produced.

  Using the obtained electrochromic device 100, the driving method (driving control) of the present proposal was carried out and its evaluation was performed.

  In Examples 1 to 3, the relational expression (1) was obtained for different coloring states, and voltage calculation was performed on the obtained expression at a time at which the open circuit voltage of the electrochromic device 100 is considered to be stable. Holding driving was performed by continuously applying. The judgment was made based on whether the optical characteristics after the lapse of a predetermined time were within the desired range.

  In Examples 4 to 6, the time variation of the open circuit voltage used in the relational expression (1) is used. After the respective coloring states of Examples 1 to 3 are taken, the holding drive is not performed and the change of the open circuit voltage with time. Was measured. The holding voltage is applied by applying the voltage again after taking each of the coloring states of Examples 1 to 3 by using the voltage for each time change of the open circuit voltage, and the determination is performed in the same manner as in Examples 1 to 3. The test was conducted.

  In Examples 7 to 9, tests were performed using the open circuit voltage measured in the same manner as in Examples 4 to 6 with respect to using the open circuit voltage after a lapse of a predetermined time when the open circuit voltage used in the relational expression (1) was stabilized.

<Example 1>
First, in the decolored state, the driving unit 17 applies a voltage of −1.8 V for 1.0 sec between the display electrode 11 and the counter electrode 13 of the electrochromic device 100 to perform color driving. The sample (electrochromic layer 12) was colored to a transmittance of 30%. Then, the open circuit voltage of the electrochromic device 100 was measured for 300 seconds. The constants A and B of the relational expression (1) between the open circuit voltage V and the time t were obtained based on the open circuit voltage and the time from the end of color driving to the relational expression (approximate formula) calculation range in Table 1 below. .. After that, color erasing drive was performed.

  Next, after performing color development driving again under the same color development condition (-1.8 V, 1.0 sec), in each relational expression (1) obtained in each relational expression calculation range, t The value of the open circuit voltage V obtained by substituting = 200 sec was defined as the open circuit voltage used for the holding drive. The changes in the constants A and B for determining the relational expression (1) were smaller than after opening, but almost disappeared around 5.00 sec or 10.00 sec. A holding drive was performed by applying the voltage for 600 seconds. The results of determining suitability of the color development state at that time are shown in Table 1 below. Several constants A and B and open circuit voltage V are shown in Table 1 below.

  Note that continuous monitoring was performed to determine whether the open circuit voltage application time during holding drive was 300 seconds and 600 seconds, and was within ± 10% of the target value (transmittance of 27 to 33%). That is, in the color development drive, it is possible to achieve a transmittance of 27 to 33% and whether or not a stable color development state is obtained without an increase in color development or a phenomenon. Judgment was made based on whether or not it was difficult to erase the color compared to the case, and there was no color remaining when the color was erased. As shown in Table 1 below, ⊚ (optimum) is that the target value ± 10% is satisfied at 600 seconds (both 300 seconds and 600 seconds are satisfied), and it is not satisfied at 600 seconds, but is satisfied at 300 seconds. The ones that were marked were rated as ○ (suitable). Those that did not satisfy the target value even at the time of 300 seconds were rated as x (unsuitable). Similar determinations were made in Examples 2 and 3 below.

<Example 2>
In Example 2, a voltage of −1.8 V was applied for 3.0 sec as a coloring condition between the display electrode 11 and the counter electrode 13 of the electrochromic device 100 to perform coloring driving, and the transmittance was up to 10%. The electrochromic layer 12 was colored. Then, similarly to Example 1, the open circuit voltage of the electrochromic device 100 was measured for 300 seconds. The constants A and B of the relational expression (1) between the open circuit voltage V and the time t were obtained based on the open circuit voltage and the time from the end of color driving to the relational expression (approximate formula) calculation range in Table 2 below. .. The changes in the constants A and B for determining the relational expression (1) were larger than those in Example 1, and were stable around 10.00 sec. After that, color erasing drive was performed.

  After color driving was performed again under the same coloring condition (-1.8 V, 3.0 sec), t = 200 sec was substituted into each relational expression (1) obtained in each relational expression calculation range as the time for the open circuit voltage to stabilize. The value of the open circuit voltage V at that time was taken as the open circuit voltage used for the holding drive. Retention driving was performed by applying each open circuit voltage V for 600 seconds. Table 2 below shows the results of determining the suitability of the decolored state at that time. Some constants A and B and open circuit voltage V are also shown in Table 2 below. In the second embodiment, it was determined at 300 sec and 600 sec whether the holding drive was within ± 10% of the target value (transmittance 9.0 to 11.0%).

<Example 3>
In Example 3, a voltage of −2.0 V was applied for 3.0 sec as a coloring condition between the display electrode 11 and the counter electrode 13 of the electrochromic device 100 to perform coloring driving, and the transmittance was up to 2%. The electrochromic layer 12 was colored. Then, similarly to Example 1, the open circuit voltage of the electrochromic device 100 was measured for 300 seconds. The constants A and B of the relational expression (1) between the open circuit voltage V and the time t were determined based on the open circuit voltage and the time until the relational expression (approximate formula) calculation range in Table 3 below. The changes in the constants A and B for determining the relational expression (1) were larger than those in Example 2, but it is considered that the changes began to be stable around 10.00 sec. After that, color erasing drive was performed.

  After performing color development drive again under the same color development condition (−2.0 V, 3.0 sec), t = 200 sec is substituted into each relational expression (1) obtained in each relational expression calculation range as the time for which the open circuit voltage stabilizes. The value of the open circuit voltage V at that time was taken as the open circuit voltage used for the holding drive. Retention driving was performed by applying each open circuit voltage V for 600 seconds. The results of determining the suitability of the decolored state at that time are shown in Table 3 below. Some constants A and B and open circuit voltage V are also shown in Table 3 below. In the third embodiment, it was determined at 300 sec and 600 sec whether the holding drive was within ± 10% of the target value (transmittance of 1.8 to 2.2%).

  As in the results of Tables 1 and 2 according to Examples 1 and 2 described above, even in the color forming drive in which the voltage is the same and the application time is changed, the voltage is applied as shown in Tables 2 and 3 according to Examples 2 and 3 above. The driving method of the electrochromic device 100 of the present invention can be applied to the color-developing drive in which the voltage is changed at the same time. Therefore, from the results of Tables 1 to 3 according to Examples 1 to 3, the driving method of the electrochromic device 100 according to the present invention is performed at any coloring driving and coloring density in a range in which the destruction of the electrochromic layer 12 can be suppressed. Can be implemented.

  From the results of Tables 1 to 3 above, after the color development driving, the open circuit voltage was measured for a predetermined period or more, preferably 10.00 sec or more, and the values of the constants A and B were calculated one after another based on the relational expression (1). , The constants A and B when the time changes of the constants A and B are stable are used as the relational expression (1) used for voltage calculation. Based on the relational expression (1) after adopting the constants A and B, the open circuit voltage after a certain period of time when the open circuit voltage stabilizes or the open circuit voltage at which the time change of the open circuit voltage is below a certain value is calculated, and the calculated voltage is calculated as It was found that the transmittance can be maintained at ± 10% of the target value by applying the voltage for a predetermined period, preferably 300 sec or more, more preferably 600 sec or more after the color development driving, and the good color development state can be maintained.

<Example 4>
First, in the decolored state, the driving unit 17 applies a voltage of −1.8 V for 1.0 sec between the display electrode 11 and the counter electrode 13 of the electrochromic device 100 to perform color driving. The sample (electrochromic layer 12) was colored to a transmittance of 30%. After that, the open circuit voltage of the electrochromic device 100 was measured over a period of 300 seconds at regular intervals (in this example, 10 msec (0.01 sec) intervals), and the time change of the open circuit voltage was calculated. After that, color erasing drive was performed. The open-circuit voltage measurement interval is not limited to 10 msec (0.01 sec) intervals, and if it is known in advance that the measurement time will be long, the measurement interval is set to 100 msec (0.1 sec), 1 It can also be set to 1,000 msec (1.0 sec) or the like.

  Next, after performing color driving again under the same color development condition (-1.8 V, 1.0 sec), the open circuit voltage when the time change of the open circuit voltage reaches the value shown in Table 4 below for 600 sec. A voltage was applied to perform holding drive. Table 4 below shows the results of determining the suitability of the coloring state at that time. The time when the time change described in Table 4 reached 1 mV / sec was 6.47 to 16.47 sec after the start of the open circuit voltage measurement, and the open circuit voltage at 6.47 sec was about −1.57 V. It was The time to reach 0.5 mV / sec was between 14.80 and 24.80 sec, and the open circuit voltage at 14.80 sec was about −1.56 V. The time to reach 0.2 mV / sec was 39.08 to 49.08 sec, and the open circuit voltage at 39.08 sec was about -1.55V. The time to reach 0.1 mV / sec was between 85.06 and 95.06 sec, and the open circuit voltage at 85.06 sec was about -1.54V. The time to reach 0.05 mV / sec was between 139.21 and 149.21 sec, and the open circuit voltage at 139.21 sec was about -1.53V.

  Note that continuous monitoring was performed to determine whether the open circuit voltage application time during holding drive was 300 seconds and 600 seconds, and was within ± 10% of the target value (transmittance of 27 to 33%). That is, in the color development drive, it is possible to achieve a transmittance of 27 to 33% and whether or not a stable color development state is obtained without an increase in color development or a phenomenon. Judgment was made based on whether or not it was difficult to erase the color compared to the case, and there was no color remaining when the color was erased. As shown in Table 4 below, those that satisfy ± 10% of the target value at 600 seconds (those that satisfy both 300 seconds and 600 seconds) are marked as ⊚ (optimal), and at 600 seconds they are not satisfied, but they are satisfied at 300 seconds. The ones that were marked were rated as ○ (suitable). Those that did not satisfy the target value even at the time of 300 seconds were rated as x (unsuitable). Similar determinations were made in Examples 5 and 6 below.

<Example 5>
In Example 5, a voltage of −1.8 V was applied between the display electrode 11 and the counter electrode 13 of the electrochromic device 100 for 3.0 sec as a coloring condition to drive coloring, and the transmittance was up to 10%. The electrochromic layer 12 was colored. Then, the open circuit voltage of the electrochromic device 100 was measured for 300 seconds in the same manner as in Example 4, and the time change of the open circuit voltage was calculated. After that, color erasing drive was performed.

  After color driving was performed again under the same coloring condition (-1.8 V, 3.0 sec), the open circuit voltage was applied for 600 sec when the time change of the open circuit voltage reached the values shown in Table 5 below. Table 5 below shows the results of the judgment when holding activities were performed. In Example 5, it was determined at 300 sec and 600 sec whether the holding drive was within ± 10% of the target value (transmittance of 9.0 to 11.0%).

<Example 6>
In Example 6, a voltage of −2.0 V was applied for 3.0 sec as a coloring condition between the display electrode 11 and the counter electrode 13 of the electrochromic element 100 to perform coloring driving, and the transmittance was up to 2%. The electrochromic layer 12 was colored. Then, the open circuit voltage of the electrochromic device 100 was measured for 300 seconds in the same manner as in Example 1, and the time change of the open circuit voltage was calculated. After that, color erasing drive was performed.

  After color driving was performed again under the same color development condition (-2.0 V, 3.0 sec), the open circuit voltage was applied for 600 sec when the time change of the open circuit voltage reached the values shown in Table 6 below. Table 6 below shows the results of the judgment when the holding activity was performed. In Example 6, it was determined at 300 sec and 600 sec whether the holding drive was within ± 10% of the target value (transmittance of 1.8 to 2.2%).

  As in the results of Tables 4 and 5 according to Examples 4 and 5 described above, even when the coloring driving is performed with the same voltage and the application time is changed, the voltage is applied as shown in Tables 5 and 6 according to Examples 5 and 6 above. The driving method of the electrochromic device 100 of the present invention can be applied to the color-developing drive in which the voltage is changed at the same time. Therefore, from the results of Tables 4 to 6 according to Examples 4 to 6, the driving method of the electrochromic device 100 according to the present invention is performed at any color driving and color density within a range where the destruction of the electrochromic layer 12 can be suppressed. Can be implemented.

  From the results of Tables 4 to 6 of the above Examples 4 to 6, the absolute value of the time variation of the open circuit voltage after the color formation drive reached the threshold value or less, preferably 0.2 mV / sec, and more preferably 0.2 mV / sec or less. By applying the open circuit voltage for a predetermined period after color driving, preferably 300 sec or longer, more preferably 600 sec or longer, the transmittance can be maintained at ± 10% of the target value, and a good color development state is maintained. I knew I could do it.

<Example 7>
First, in the decolored state, the driving unit 17 applies a voltage of −1.8 V for 1.0 sec between the display electrode 11 and the counter electrode 13 of the electrochromic device 100 to perform color driving. The sample (electrochromic layer 12) was colored to a transmittance of 30%. Then, the open circuit voltage of the electrochromic device 100 was measured for 300 sec (1 sec, 10 sec, 100 sec, 200 sec, 300 sec). After that, color erasing drive was performed.

  Next, color driving was performed again under the same color developing conditions (-1.8 V, 1.0 sec), and then each measurement voltage of the open circuit voltage was applied for 600 sec to carry out a holding activity. Table 7 below shows the results of determining the suitability of the coloring state at that time.

  Note that continuous monitoring was performed to determine whether the open circuit voltage application time during holding drive was 300 seconds and 600 seconds, and was within ± 10% of the target value (transmittance of 27 to 33%). That is, in the color development drive, it is possible to achieve a transmittance of 27 to 33% and whether or not a stable color development state is obtained without an increase in color development or a phenomenon. Judgment was made based on whether or not it was difficult to erase the color compared to the case, and there was no color remaining when the color was erased. As shown in Table 7 below, ⊚ (optimum) means that ± 10% of the target value is satisfied at 600 sec (both 300 sec and 600 sec are satisfied), and it is not satisfied at 600 sec, but is satisfied at 300 sec. The ones that were marked were rated as ○ (suitable). Those that did not satisfy the target value even at the time of 300 seconds were rated as x (unsuitable). Similar determinations were made in Examples 8 and 9 below.

<Example 8>
In Example 8, a voltage of −1.8 V was applied between the display electrode 11 and the counter electrode 13 of the electrochromic device 100 for 3.0 sec as a color-developing condition to drive the color-developing, and the transmittance was up to 10%. The electrochromic layer 12 was colored. Then, as in Example 7, the open circuit voltage of the electrochromic device 100 was measured for 300 seconds. After that, color erasing drive was performed.

  Table 8 below shows the determination results when the measured voltage of the open circuit voltage was applied for 600 sec in the holding drive after the color development drive was performed again under the same color development condition (-1.8 V, 3.0 sec). In Example 8, ± 10% of the target value was set as the transmittance of 9.0 to 11.0%.

<Example 9>
In Example 9, a voltage of −2.0 V was applied as a coloring condition for 3.0 sec between the display electrode 11 and the counter electrode 13 of the electrochromic device 100 to perform coloring driving, and the transmittance was up to 2%. The electrochromic layer 12 was colored. Then, as in Example 7, the open circuit voltage of the electrochromic device 100 was measured for 300 seconds. After that, color erasing drive was performed.

  Table 9 below shows the determination results when each measurement voltage of the open circuit voltage was applied for 600 sec in the holding drive after color development drive was performed again under the same color development condition (-2.0 V, 3.0 sec). In Example 3, ± 10% of the target value was set as the transmittance of 1.8 to 2.2%.

  As in the results of Tables 7 and 8 according to Examples 7 and 8 described above, even when the color formation driving is performed with the same voltage and the application time is changed, the voltage is applied as shown in Tables 8 and 9 according to Examples 8 and 9 above. The driving method of the electrochromic device 100 of the present invention can be applied to the color-developing drive in which the voltage is changed at the same time. Therefore, from the results of Tables 7 to 9 according to Examples 7 to 9, the driving method of the electrochromic device 100 according to the present invention is performed at any color-forming driving and color-developing density within the range in which the destruction of the electrochromic layer 12 can be suppressed. Can be implemented.

  From the results of Table 7 to Table 9 above, the open circuit voltage of the electrochromic element 100 is measured after a predetermined period of time has elapsed, preferably 100 seconds has elapsed, more preferably 200 seconds has elapsed, and further preferably 300 seconds has elapsed, from the color formation drive. Then, it was found that by applying the measured open circuit voltage for a predetermined period, preferably 600 seconds or more after the color development driving, the transmittance can be maintained at ± 10% of the target value, and a good color development state can be maintained.

  The calculation voltage application and the calculation using the relational expression (1) have been described above. Hereinafter, a case where the calculation voltage application is performed by a pulse and a case where the application timing is determined based on the difference between the open voltage and the open circuit voltage will be described.

<Example 10>
As Example 10, a driving method of applying an open circuit voltage to the electrochromic element 100 in a pulse shape will be described. In Example 10, a voltage of −1.8V was applied between the display electrode 11 and the counter electrode 13 for 1.0 sec as a coloring condition to perform coloring driving, and then a voltage of −1.53V was applied. Application and release (OC) were repeated at a duty ratio of 1.53%. As a result, the transmittance after 600 seconds satisfied the target value ± 30% (transmittance 27 to 33%) as in the case of continuous application, and the power consumption during the holding drive decreased.

<Example 11>
As Example 11, a test was conducted under the condition different from that of Example 10. Color development was set to 10% by applying -1.8 V for 3.0 seconds. After driving the color development, voltage application at −1.66 V and opening (OC) were repeated at a duty ratio of 5.00%. As a result, the transmittance after 300 seconds satisfied the target value ± 10% (transmittance 9.0 to 11.0%) as in the case of continuous application, and the power consumption during the holding drive decreased.

<Example 12>
As a twelfth embodiment, a driving method for applying a calculated voltage to the electrochromic device 100 will be described. In Example 10, a voltage of −1.8 V was applied between the display electrode 11 and the counter electrode 13 for 1.0 sec as a coloring condition to perform coloring driving, and then based on the relational expression (1). The absolute value of the calculated voltage −1.53V and the absolute value of the open circuit voltage between the electrodes are compared, and when the calculated voltage is large and the difference is 0.03V or more, −1.53V, 1.0 sec. Was applied. As a result, the transmittance after 3600 seconds satisfied the target value ± 10% (transmittance 27 to 33%).

<Example 13>
As Example 13, a test was conducted under the condition different from that of Example 12. Color development was set to 10% by applying -1.8 V for 3.0 seconds. After color driving, the absolute value of −1.66V and the absolute value of the open circuit voltage between the electrodes are compared, and when the calculated voltage is large and the difference is 0.02V or more, −1.66V, 1 Application was performed for 0.0 seconds. As a result, the transmittance after 3600 seconds satisfied the target value ± 10% (transmittance 9 to 11%).

  The color erasing state was judged for the case where the color erasing was performed immediately after the electrochromic element 100 was colored, and the case where the color erasing driving was performed 300 seconds after the holding driving was not performed. When the color erasing activity is performed immediately, some color remains when the maximum color erasing voltage is less than + 0.5V, it almost disappears when the voltage is + 0.5V or more and less than + 1.5V, and the color is erased by applying + 1.5V or more, but excessive color erasing. The result was obtained. Further, in the case of carrying out after 300 seconds, if it is less than +0.5 V, it becomes slightly thin, and even if the time is doubled, the color is not completely erased, and even if +2.0 or +2.5 V is applied, some color remains and it is difficult to erase. The result was obtained. That is, it is necessary to increase the time for erasing driving and increase the erasing voltage. On the other hand, the driving method of the electrochromic device 100 according to the present invention resulted in almost disappearing at +0.5 V or more and less than +1.5 V during decoloring.

  Furthermore, in the method for driving the electrochromic device 100 according to the present invention, when the holding drive is performed with an open circuit voltage after 100 seconds (judgment ◯) and 200 seconds or 300 seconds (judgment ◎) from the color development driving, the color is erased. The result was easy. That is, it becomes possible to reduce the time for erasing driving and the erasing voltage.

<Example 14>
As Example 14, samples having different optical characteristics and electrical characteristics are prepared, coefficients A and B are calculated from the open circuit voltage in the same manner, and holding driving is performed by using an approximate expression using the coefficients A and B at the stable state. It was Here, the prepared sample shows high color development under a lower application condition than the electrochromic device 100 described above. Specifically, in the case of the electrochromic device 100, 30% color development can be obtained by applying -1.8 V for 1.0 sec, but the sample used in Example 14 is -1.3 V, 1.0 sec. It is possible to obtain a color development of 30%. Moreover, since the tint is different from that of the electrochromic element 100, the calculation of the representative wavelength and the average wavelength with the transmittance of 30% is different. Using this sample, as in the electrochromic device 100, after the color was developed, the constants A and B were calculated using the voltage monitor in the open state and the relational expression (1), and the constants A and B were calculated. As a result of determining the applied voltage from the time and the slope with respect to the stable constants A and B, it was calculated to be -1.17V. When this voltage was continuously applied, the transmittance after 300 seconds satisfied the target value ± 10% (transmittance 27 to 33%).

<Example 15>
As Example 15, using a sample manufactured under the same conditions as in Example 14, after driving color development at −1.3 V for 1.0 sec, voltage application at −1.17 V and opening (OC) were performed at a duty ratio of 5. Repeated at 00%. As a result, as in the case of continuous application, the transmittance after 300 seconds satisfied the target value ± 10% (transmittance 27.0 to 33.0%), and the power consumption during the holding drive decreased.

<Example 16>
As Example 16, a sample prepared under the same conditions as in Example 14 was used, and after color development driving at -1.3 V and 1.0 sec, the absolute value of -1.17 V and the absolute value of the open circuit voltage between the electrodes were compared. Then, when the calculated voltage is large and the difference is 0.02 V or more, the voltage is applied at -1.17 V for 1.0 sec. As a result, the transmittance after 3600 seconds satisfied the target value ± 10% (transmittance 27 to 33%).

  Further, it was attempted to see the difference in decolorization between when nothing was done after color development and when holding driving was performed, but in this sample, which has a lower memory property than the electrochromic device 100, color development occurs after 600 seconds have elapsed in the open state. Most of them were alleviated with the passage of time, and an experiment for the effect of fading easily was not possible.

  Although the embodiments of the present invention have been described in detail above with reference to the drawings, the above embodiments are merely examples of the present invention, and the present invention is not limited to the configurations of the above embodiments. .. Design changes and additions are allowed without departing from the gist of the present invention. Further, the number, position, shape, etc. of the constituent members are not limited to each embodiment, and can be any number, position, shape, etc. suitable for carrying out the present invention.

10 Display Substrate 11, 21, 31 Display Electrode 12, 22, 32 Electrochromic Layer 13 Counter Electrode 14 Counter Substrate 15 Electrolyte 17 Driving Means 100, 200 Electrochromic Element

Japanese Patent Publication No. 5-23409 JP, 2003-270671, A

Claims (5)

A first electrode, a second electrode facing the first electrode with a gap, an electrolyte provided between the two electrodes, and at least an electrochromic compound or an electrochromic composition, A method for driving an electrochromic device, comprising: driving an electrochromic device including an electrochromic layer formed on a surface of at least one of the two electrodes,
A voltage is applied between the first electrode and the second electrode to cause the electrochromic layer to develop color, and then an open circuit voltage between the first electrode and the second electrode is measured, When the elapsed time from the application of the voltage for color development is t, the open circuit voltage measured at the elapsed time t is V, and the constants are A and B, the following equation (1)
(1) V = A * Ln (t) + B
Based on the above, the open circuit voltage at which the absolute value of the open circuit voltage or the time change of the open circuit voltage after the lapse of a predetermined period during which the open circuit voltage stabilizes is equal to or less than a threshold value is calculated, and the open circuit voltage between the first electrode and the second electrode is calculated. The method for driving an electrochromic device is characterized in that a calculated voltage calculated based on the above formula (1) is applied to.   The method of driving an electrochromic device according to claim 1, wherein the calculated voltage is continuously applied for a predetermined period after the color-developed state is obtained.   The method for driving an electrochromic device according to claim 1, wherein the calculated voltage is applied in a pulse form.   The method for driving an electrochromic device according to claim 1, wherein the color development timing at the calculated voltage is determined by comparing the calculated voltage and the open circuit voltage. A first electrode, a second electrode facing the first electrode with a gap, an electrolyte provided between the two electrodes, and at least an electrochromic compound or an electrochromic composition, An electrochromic device for driving an electrochromic device comprising an electrochromic layer formed on the surface of at least one of the two electrodes,
A voltage is applied between the first electrode and the second electrode to cause the electrochromic layer to develop color, and then an open circuit voltage between the first electrode and the second electrode is measured, When the elapsed time from the application of the voltage for color development is t, the open circuit voltage measured at the elapsed time t is V, and the constants are A and B, the following equation (1)
(1) V = A * Ln (t) + B
Based on the above, the open circuit voltage at which the absolute value of the open circuit voltage or the time change of the open circuit voltage after the lapse of a predetermined period during which the open circuit voltage stabilizes is equal to or less than a threshold value is calculated, and the open circuit voltage between the first electrode and the second electrode is calculated. An electrochromic device, characterized in that a driving means for applying a calculated voltage calculated based on the formula (1) is provided.