JPS6013162B2 - Manufacturing method of electrochromic display element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an electrochromic display element in which a transition metal oxide layer exhibiting electrochromism is sandwiched between a pair of electrode substrates.

For example, transition metal oxides such as tungsten oxide, molybdenum oxide, titanium oxide, vanadium oxide, niopium oxide, tantalum oxide, zirconium oxide, hafnium oxide, and lanthanum oxide are known as materials exhibiting electrochromism.

However, electrochromic display elements that utilize electrochromism of transition metal oxides are also known. The basic structure of this electrochromic display element is such that the transition metal oxide layer is sandwiched between opposing electrodes, at least one of which is transparent. In order to improve the display contrast, response, or lifespan of this basic configuration, for example, a liquid or solid electrolyte may be sandwiched between the electrode substrates adjacent to the transition metal oxide layer, or a transition metal oxide layer may be sandwiched between the electrode substrates. A structure in which two oxide layers are provided and an electrolyte layer is interposed between these two layers is also known. Incidentally, the transition metal oxide layer which forms the main part of these electrochromic display elements is formed in the following manner. That is, the transition metal oxide powder is molded and solidified, and it is formed by depositing it in a layer on an electrode substrate using a vacuum evaporation method or a sputtering method. However, the formation of a transition metal oxide layer by the above method has the following disadvantages. First, the powder metallurgy method involves forming and sewing a thin homogeneous transition metal oxide layer with a thickness of about 0.1 to several tens of peaks, which is necessary for this type of display element to exhibit good display performance. . Therefore, regarding the display element in this case, the display response is slow, the operating voltage required for display is quite high, several hundred volts, and uneven display contrast due to the above-mentioned uneven thickness is unavoidable. . Next, when vapor deposition or sputtering is used, ``the required thickness of the transition metal oxide layer is almost no problem if it is a small area, but it is difficult to form a thin layer with a uniform thickness over a fairly large area. There is a natural limit to the size of display elements that can be displayed.
Moreover, it is economically disadvantageous as it requires complicated operations and expensive equipment. Therefore, the present invention provides an electrochromic method that includes means for forming a transition metal oxide layer of any desired thickness and overall uniform thickness on an electrode substrate surface of any size using simple means. The present invention aims to provide a method for manufacturing a display element.

To explain the present invention in detail below, the present invention relates to a method for manufacturing an electrochromic display element in which a transition metal oxide layer is sandwiched between counter electrode substrates, at least one of which is transparent. This method of manufacturing an electrochromic display element is characterized in that a solution containing a transition metal compound is applied and baked to form and sandwich the transition metal oxide layer.

Examples of inorganic transition metal compounds used in the present invention include halides such as tungsten halide and molybdenum halide, oxygen acid compounds such as tungstic acid, molybdic acid, metatungstic acid, and paratungstic acid, and salts such as sodium tungstic acid and lithium tungstic acid. These compounds may be used alone or in a mixed system of two or more.

Further, in the present invention, only the inorganic transition metal compounds mentioned in the above three edicts may be used, but for example, one or more organic transition metal compounds such as butyl titanate, molypdenium acetylacetonate, hexaphenoxytungsten, and pentaethoxytungsten. may be added and blended as appropriate. However, as the solvent used to make these transition metal compounds into a solution, water and alcohols are preferable in the case of inorganic transition metal compounds, and alcohols and cellosolves are preferable in the case of containing organic transition metal compounds. etc. are preferable.
4 In the present invention, the concentration of the solution containing the inorganic transition metal compound is arbitrarily selected and adjusted depending on the desired thickness of the transition metal oxide layer. The transition metal compound solution is applied onto the electrode substrate surface by a dipping method, a spray method, or a spinner method.Furthermore, the baking after the application causes the transition metal compound to thermally decompose, forming a transition metal oxide layer. The temperature and time are such that they can be produced or formed. Generally, the above-mentioned firing is carried out in air or in an oxygen atmosphere at 350 to 650 qo for several minutes to several hours. When applying the above transition metal compound solution, for example, glycerin, ethyl cellulose, etc. may be added as appropriate to improve the coating film (to improve adhesion), and the transition metal oxide to be formed may also be added. Other metals or metal compounds may be added to improve the display properties of the layer.

Next, examples of the present invention will be described.

Example 1 A solution prepared by dissolving 40 g of tungstic acid in 800 g of 14% ammonia water was applied onto one surface of a 30 x 25 square transparent electrode substrate (Nesa Glass) by dip coating method, and after drying, it was coated at 480 qo for 60 minutes. A tungsten oxide layer having a thickness of about 0.1 mm per layer was formed on the substrate surface.

The two electrode substrates provided with the above tungsten oxide layer were superimposed with each other with the tungsten oxide layers facing each other via a glass substrate having a thickness of 1 layer to assemble a display element cell.

Next, a sulfuric acid-glycerin-titanium dioxide (mixing ratio 1:4:1) electrolyte was injected and filled between the tungsten oxide layers of this display element cell to obtain a display cell. Figure 1 is a cross-sectional view of an example of the structure of the display cell constructed in this way.
, 1' is a transparent electrode substrate equipped with transparent electrodes 2, 2';
3' is the tungsten oxide layer, 4 is the glass baser, and 5 is the tungsten oxide layer.
indicate electrolytes, respectively.

When an AC rectangular wave and a voltage of 0.5Hz ± 0.2V were applied to the above display cell, colorless (white) and blue color development and fading were observed, and an applied voltage of 0.3Hz and 3.5V was sufficient. It exhibited a deep tone color development, and the color development/decolorization response sufficiently followed 0.5 HZ.

Example 2 Using a solution prepared by dissolving 60 parts of tungsten hexachloride and 3 parts of ethyl cellulose in 240 parts of n-butyl alcohol, solution coating and baking treatment was performed under the same conditions as in Example 1 to obtain a film with a film thickness of about 0. A tungsten oxide layer of .2 μm was provided on the surface of the transparent electrode substrate.

When a color development/decolorization test was conducted on a display cell configured using this electrode substrate under the same conditions as in the example, an alternating current rectangular wave of 0.5Hz±1. When a separate voltage is applied, a blue color develops and disappears.
It was also confirmed that the blue color density improved by applying 2±3 V for 0.5 days, and that the response sufficiently followed 0.5 HZ. Example 3 1500% n-butyl alcohol, 100% pentaethoxytungstate, 6% molybdenum besotachloride
．． First, a solution was prepared by dissolving [25] and acetylacetone.

Next, this solution was coated on a 30 x 25 transparent electrode substrate (NESA glass) surface, dried, and then fired at 500 CO for 60 minutes to form a tungsten oxide-molybdenum oxide mixture layer with a thickness of 0.4 r. A display cell was constructed under the same conditions as in Example 1 using two electrode substrates on which the oxide mixture layer was formed.

When an AC rectangular wave of 1.0 V and 1.5 V was applied to this display cell, pale blue color development and fading were observed.
．． The color density was sufficiently improved by applying 0HZ and 2.0N. Furthermore, when we measured the absorption spectrum of the above color development, we found that the maximum absorption wavelength was 62 mm.Compared to the case of the tungsten oxide layer alone, which had a maximum absorption wavelength of 80 mm, the maximum absorption wavelength has shifted to a considerably shorter wavelength. Example 4 A solution prepared by dissolving 1500 parts of n-butyl alcohol, 100 parts of pentabutoxitasogstate, 15 parts of manganese dichloride tetrahydride and 25 parts of acetylarcetone was used. Example 3
The display cells were configured under the same conditions as in the case of .

When a direct current was applied to the display cell configured as described above, the transition metal oxide layer of the negative electrode example showed a red color at about IV, and when the applied voltage was further gradually increased, it showed a green color at about 5V.

When the polarity of the oxide layer showing this green color was reversed and approximately W was applied, a tree-like color was obtained. As is clear from the above examples, according to the method of the present invention, a uniform transition metal oxide layer of any desired thickness can be formed with a simple operation.

Moreover, since the transition metal oxide layer can be formed to have a uniform thickness even in a relatively large shape, it can be used to construct a desired electrochromic display element regardless of the size. Thus, the method of the present invention can be applied to the produced electrochromic display element (display cell).
This method can be said to be a method of manufacturing display elements with high practical value, since it has a display ability with good contrast.

[Brief explanation of the drawing]

The drawing is a sectional view showing an example of the structure of an electrochromic display element manufactured by the method of the present invention. 1, 1'...Transparent electrode substrate, 3, 3'...
...Tungsten oxide layer, 4...-Glass baser, 5. ．．・．． ．． ·Electrolytes.

Claims (1)

[Claims] 1. A method for manufacturing an electrochromic display element in which a transition metal oxide layer is sandwiched between opposing electrode substrates, at least one of which is transparent, wherein an inorganic transition metal compound solution is placed on at least one of the electrode substrates. A method for manufacturing an electrochromic display element, comprising forming and sandwiching the transition metal oxide layer by coating and baking. 2. The method for producing an electrochromic display element according to claim 1, wherein the solution applied onto the electrode substrate contains an organic transition metal compound in addition to an inorganic transition metal compound.