JPS59174822A - Manufacture of electrochromic display element - Google Patents

Abstract

PURPOSE:To prevent variance in quality by arranging a specific high polymer material between two substrate previously. CONSTITUTION:An insulating film 8 is provided to an SnO2 transparent electrode 7 on a glass substrate 4 except at a display pattern part and a connection part by vapor-depositing MgF2 800Angstrom , and WO3 is vapor-deposited on this electrode to 3,000Angstrom to form a WO3 film in a pattern shape, thus forming a display electrocde 3. A sealing material 6 is printed at the circumference except a sealing part and hardened, and then a polyacrylonitrile film (high polymer material) which is dried by a vacuum dryer previously and sufficiently and has an about 50mum thickness is provided on the display electrode inside of the sealing material 6. Further, MgF2 is vapor-deposited on the SnO2 transparent electrode 7 except at the display pattern part and electrode lead connection part on the other substrate 5 and purrusian blue is vapor-deposited to 1,500Angstrom to form a counter electrode 2. Both substrates are superposed and a support electrolyte is injected after the sealing material 6 is hardened to form an electrochromic display element. The high polymer material is arranged between the substrates 1, so variance in quality is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an electrochromic display element including a polymer ion conductor layer.

In recent years, the amount of light absorbed by electrochemical redox reactions. Research on so-called electrochromic elements that reversibly change their properties and that can be used as display elements, anti-glare mirrors, and variable transmittance glasses has been active. The most important features of this device, compared to liquid crystal devices, include 1) wide viewing angle, 2) memory properties, 3) continuously variable light absorption, and 4) ease of upscaling.

The structure of a typical electrochromic device is shown in FIG.

In this electrochromic element, first, a transparent conductive layer 7 is provided on a transparent front substrate 4 such as glass, and a display electrode 8 is further formed on this conductive layer 7. The transparent conductive layer 7 generally has a low resistance of 500/hole or less and a high light transmittance of 80% or more. This transparent conductive layer 7 is made of SiO, Sin
Alternatively, an insulating film 8 of MgF 2 or the like is provided by a method such as vapor deposition or sputtering. As the display electrode 8, tungsten oxide, which is an electrotetrachromic substance, (W
A material that develops color upon reduction and disappears upon oxidation, such as a transition metal oxide insoluble in the electrolyte such as molybdenum oxide (Mo08) or molybdenum oxide (Mo08), is provided by a method such as vapor deposition. −
Similar to the front substrate 4, a transparent conductive layer 7 is provided on the blade back substrate 5, and an insulating coating 8 is provided on areas other than the connection portions of the lead wires and the display pattern. And Prussian blue is used as the counter electrode 2.

A material that develops color by oxidation and disappears by reduction, such as ruthenium purple, or a transition metal oxide that is insoluble in an electrolyte, such as Ni, O2, O2O8, etc., as a nearly transparent electrochromic substance, is provided by a method such as electrodeposition or vapor deposition. . These substrates 4 and 5 are held in parallel by a sealant 6 to form an empty cell. Next, an electrolyte is injected into the cell through the injection port, and after an ion conductive layer is formed, the injection port is sealed. The electrochromic display element constructed in this way develops color when an appropriate voltage is applied between the display electrode and the counter electrode, and conversely, when a reverse voltage is applied between both electrodes, the image on the display electrode changes. The color fades and returns to its original transparent state. In this way, it becomes possible to function as a display element.

The ion conductive layers constituting such conventional electrochromic display elements include 1) propylene carbonate, ethylene carbonate,
Li0zO, +
Li0z r LiBr, LiBF, r LiP
F6+NaIO,I Nap/ , NaBr,
NaBF, I NaPF61KO10,,K(31,
KBr, KBF4. Non-aqueous liquid ionic conductive material in which an alkali metal salt such as KPF6 is dissolved as a supporting electrolyte, 2) ZrO2, Ta205.5rTiO8+ Nb
2O3,0aF2゜V2O5,TiO2,BaTiO3
,0aTiO8,PbF2.0r208pbo, L
iy, aacl, mgF2. aa8(po,)
Solid ionic conductive materials such as No. 2 to which a trace amount of water was added were used.

On the other hand, the following characteristics are required for the ion conductive layer.

■) High ionic conductivity (0'C-40'C, near room temperature).

2) The electrochromic material must be stable during redox reactions.

3) It is easy to manufacture the device and increase the surface area.

4) Must be durable.

However, liquid ion conductive materials leak when the assembled cell is stored for a long period of time or subjected to thermal shock, so cell sealing technology has become a problem. In addition, solid ion conductive materials have low ionic conductivity, so they are used as thin films (~1,000 layers), but they generate pinholes, and if they are made into a single large device, this will cause a short circuit between the upper and lower electrodes, resulting in no display. Further, there is a problem that the decomposition of the adsorbed water causes the film to peel off due to the generation of oxygen or hydrogen, resulting in no display.

Against this background, Makromoz, Ohem,
.

RapidGommun, 2,741-744 (1
Polyacrylonitrile as described in 981).

Polyvinyl butyral, polyvinylidene fluoride.

It is expected that a polymeric ionically conductive material obtained by dissolving the non-aqueous liquid ionically conductive material in a polymeric material such as polyethylene oxide or polyvinyl alcohol will satisfy the above characteristics. This polymeric ionic conductive material generally further contains a small amount of water (1 to 8% by weight) to increase its electrical conductivity.

In order to reduce the resistance between the electrodes of the upper and lower substrates, such a polymer ion conductive layer needs to control a predetermined film thickness and the composition ratio of the polymer material, solvent, and supporting electrolyte.

However, the conventional method of forming a polymer ion conductive film is to mix a polymer material and a supporting electrolyte in a predetermined ratio, dissolve the resulting solution in a large amount of solvent, and then sequentially stack a transparent conductive layer and an electrochromic layer. Spin coating or dip coating a mixture of polymer material, supporting electrolyte, and solvent onto a transparent substrate.

There is a method in which the device shown in Figure 1 is manufactured by applying the coating using a coating method such as spray coating or roll coating and then drying to form an ion conductive layer, but this method results in variations in response speed between each device. has grown.

Therefore, we investigated the cause of this problem and found that it was because the conductivity of the ion conductive layer varied because the amount of solvent that evaporated during drying could not be controlled at a constant level. However, in order to eliminate this variation, drying conditions (temperature, degree of vacuum for 9 hours)
It is not enough to simply control the initial polymer material and supporting electrolyte ratio, etc., which are intricately intertwined and cause variations, making it extremely difficult to solve this problem.

This invention was made by focusing on these conventional problems, and uses a polymer material as an ion conductive layer.

When manufacturing an electrochromic display element that includes a polymer ion conductive layer containing a predetermined amount of each of a solvent and a supporting electrolyte, in the step of providing the polymer ion conduction layer, only the polymer material or the polymer material and a predetermined amount or less of each are added. The supporting electrolyte mixed and dispersed material is placed between two substrates, and then these two substrates are placed facing each other and the peripheral portions are adhesively sealed to form a cell, and the ratio of the solvent and the supporting electrolyte is set to a predetermined ratio. The above-mentioned problems are solved by sealing a liquid or an organic solvent consisting of the above-mentioned electrochromic cell into the electrochromic cell to form a polymer ion conductive layer containing predetermined amounts of each of a polymer material, a solvent, and a supporting electrolyte. .

The present invention will be explained below with reference to the drawings.

A typical electrochromic display element of this invention is
The ion conductive layer l shown in FIG. 1 is formed of a polymer ion conductive film. In forming this display element, as already explained for the display element in FIG.
A transparent conductive layer 7 and a display electrode 3 are disposed on a transparent front substrate 4 such as glass.
- A transparent conductive layer 7 and a counter electrode 2 are also provided on the blade back substrate 5.
will be established. Next, these substrates 4 and 5 are held parallel to each other by a sealant 6 with the polymer ion conductive layer 1 in between.

The method for forming the polymer ion conductive layer at this time will be described in detail.

(1) A polymer material film, such as a thin film layer of polyacrylonitrile, is formed on one substrate (for example, the substrate on which a display electrode is formed) by one of the following methods. To do this, a) place a film-like material (approximately 50 μm thick) prepared in advance or dissolve and dilute it using, for example, a 25% LiG104 propylene carbonate solution as a solvent (approximately 500 cp).
Coat the shredded food with a spinner, etc.

(2) Sprinkle spacer material (glass fiber, etc.) with a diameter of about 5 μm on the formed polymeric material film.

(3) Screen print a sealant on the other substrate (for example, one electrodeposited with Prussian blue) except for the electrolyte injection port.

(4) Both types of plates are overlapped and the sealant is heated and cured using a press or a rubber roll to form cells.

(5) Furthermore, an electrolyte of a predetermined concentration, for example, a propylene carbonate solution of 2 (mol/t) Li (31O) or only the required amount of propylene carbonate, is injected into the obtained cell, and the injection port is sealed with an adhesive. .

(6) Finally, the obtained device is heated at 100'C for 1 hour to obtain a uniform polymeric ion conductive layer with a stacking ratio of polyacrylonitrile:propylene carbonate:Li0t04 of 4:8:1.

The method for injecting the electrolyte is to place the cell and the container containing the electrolyte solution for injection into a device capable of reducing pressure, to sufficiently exhaust the gas dissolved in the cell and liquid, and to bring the inside of the device into a sufficiently reduced pressure state. After that, a method is used in which the injection port of the cell is immersed in the electrolyte, the reduced pressure is released, and the electrolyte is injected into the cell.

By producing an electrochromic display element containing a polymer ion conductive layer using the above method, it has become possible to easily control the component ratio of the polymer ion conduction layer, so that the resulting device has the following properties: There is little variation in response.

The polymer materials in the polymer ion conductive material used in this invention are polyvinylidene fluoride, including polyacrylonitrile, and polyethylene oxide.

It is a polymeric material such as polyvinyl alcohol, and has a dielectric constant of 3 or more, and the aforementioned propylene carbonate, ethylene carbonate, and γ are used as ordinary electrolyte solutions.
-butyl lactone, N,N-dimethylformamide,
It is preferable to use polymeric materials that are highly compatible with solvents such as acetonitrile alone or as a mixture □.

Further, the proportion of the polymer material in the polymer ion conductive material used in this invention is preferably 40 to 95% by weight,
If the polymer material is less than 40% by weight, liquid leakage may occur.
On the other hand, if it exceeds 95% by weight, conductivity cannot be obtained. The ratio of the electrolyte to the solvent is preferably about 0.2 to 5, and must be appropriately selected depending on the required electrical conductivity.

In addition, the thickness of the polymeric ion conductive layer can be controlled to a uniform film of 8 to 100 μm by adjusting the diameters of the polymeric thin film and the spacer material such as glass fiber or alumina powder.

Furthermore, although the polymer ion conductive material is transparent, Ti
When a colored powder such as O2 is mixed and dispersed, it becomes opaque and can be used as a thin reflective electrochromic display element without providing a light scattering plate such as an alumina substrate.

As explained above, the method for producing an electrochromic display element of the present invention having a polymer ion-conductive layer as an ion-conducting layer is to electrochromicly produce a polymer material, or a polymer material and a supporting electrolyte mixed and dispersed material in a predetermined amount or less. In order to produce an electrochromic display element by disposing it in a chromic cell and then sealing a liquid mixture of a solvent and a supporting electrolyte or an organic solvent in the electrochromic cell to form a polymer ion conductive layer.
The variation in response speed among the fabricated elements is low and M
The effect is that an electrochromic display element can be produced.

Next, the present invention will be explained in detail with reference to examples.

Example 1 S on a glass substrate (width 10011 fi x length l 00 tns) excluding the display pattern part and electrode lead connection part
800 people heat vapor deposition of MgF2 on nO2 transparent electrode, MgF
2 insulation coating was provided. WO2 at 300O on this electrode
A was vapor-deposited and a WO2 film was formed in a pattern to form a display electrode. Furthermore, a sealant was printed around the area excluding the sealing part, and after temporary curing, it was thoroughly dried in a vacuum dryer to a thickness of about 5cm.
A 0 μm polyacrylonitrile film was provided on the top of the display inside the sealant. Furthermore, 80 OA of MgF 2 was vapor-deposited on the other substrate, the SnO 2 transparent electrode except for the display pattern portion on the board and the electrode lead connection portion, to provide an MgF 2 insulating film. On this electrode
Jliil, a Prussian blue film was provided, and a counter electrode was created. After stacking these side substrates, the sealing material was cured to produce a cell of an electrochromic display element. After thoroughly evacuating this cell, propylene carbonate, which is a solvent containing LiClO4, which is a supporting electrolyte of 2 (mol/l) containing a predetermined amount of water, is injected into the cell, and the cell is sealed. An electrochromic display element having the structure shown in FIG. Polyacrylonitrile: brobylene carbonate): Li, GtO,
The weight ratio was 4:8:l, and 100 electrochromic display elements were manufactured. For comparison, a display electrode was formed on the front substrate in the same manner as above, and after printing a sealant, polyacrylonitrile and Li0zO were mixed at a ratio of 2:1.
Mix this in a weight ratio of 1 layer of polyacrylonitrile to 10 parts by weight of propylene carbonate, spin coat the solution and dry it to form a polymer ion conductive layer of about 50 μm on the inside of the sealant. It was set at the highest level. Thereafter, 100 conventional electrochromic display elements were manufactured in the same manner. The response speed of each of these elements was measured. Figures 2a and 2b show variations in response speed when a coloring voltage of 1.2V is applied to these elements.

FIG. 2a shows the results for the device of the example, and FIG. 2A shows the results for the conventional device. From these results, it is clear that the variation is reduced by using the manufacturing method of the present invention.

Example 2 Same as Example 1 except that a 50 μm thick polymer material and supporting electrolyte mixed and dispersed membrane in which polyacrylonitrile as a polymer material and Li0tO as a supporting electrolyte were mixed and dispersed at a weight ratio of 2:1 was used. In the same manner, 100 cells of an electrochromic display element were constructed, and γ-butyrolactone was injected as a solvent into these cells to seal them. The response speed of the electrochromic display element thus constructed was measured in the same manner as in Example 1, and the results are shown in FIG. It can be seen from this that the response speed is made uniform as in the first embodiment.

Example 3 100 electrochromic display elements were produced in the same manner as in Example 1 except that an 80 μm film of polyvinyl butyral was used as the polymer material for the polymer ion conductive layer. The response speed of the display element thus produced was measured in the same manner as in Example 1, and the results are shown in FIG. It is clear from this that the response speed is made uniform as in the first embodiment.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a typical electrochromic display element; Fig. 2a is a graph showing the response speed of the display element of Example 2; Fig. 2 is a graph showing the response speed of the conventional display element; FIG. 4 is a graph showing the response speed of the display elements of Examples 3 and 4, respectively. 1... Ion conductive layer or polymer ion conductive layer 2...
・Counter electrode 3...Display electrode 4...Top substrate
5...Back board 6...Sealant
7...Transparent conductive layer 8...Insulating film. Patent applicant: Nissan Motor Co., Ltd. Figure 2 a b 125 Figure 3 Figure 4

Claims (1)

[Claims] L In a method for manufacturing an electrochromic display element having a polymer ion conductive layer containing a solvent and a supporting electrolyte at predetermined positions in a polymer material, a polymer material alone or a polymer material and a supporting electrolyte of a predetermined density or less are prepared in advance. A mixed and dispersed material is placed between two substrates, and then the periphery of the substrates is adhesively sealed to form a cell, and then a mixed liquid of a solvent and a supporting electrolyte or only the solvent is sealed in the cell. A method for manufacturing an electrochromic display element, characterized by forming a polymer ion conductive layer.