JPS62283322A - Manufacture of electrochromic display device - Google Patents

Abstract

PURPOSE:To obtain an electrochromic display device which provides a uniform display by performing a heat treatment while bringing the entire back surface of an ITO glass substrate into surface contact with the flat part of a mount base made of metal. CONSTITUTION:The ITO glass substrate 2 formed by an ion plating method is heat-treated under conditions of 10<-5>Torr in degree of vacuum and 450 deg.C for 3hr. This heat treatment is carried out while the entire back surface 20 of the ITO glass substrate 2 is brought into surface contact with the flat part 10 of the mount base 1 (with 2mm thickness) made of stainless steel so that at least part of the surface is made into the flat part 10. The IT glass substrate 2 is heated and cooled more uniformly in the heat treatment. Consequently, the temperature distribution at the time of the heat treatment of the ITO glass substrate 2 is as uniform as possible and the uniformity of the ITO film 21 of the ITO glass substrate 2 is improved, thereby reducing variance in the electronic resistance of an ITO film 21 with the position.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for manufacturing an electrochromic display device, and more specifically, the present invention relates to a method for manufacturing an electrochromic display device, and more specifically, a method for manufacturing an electrochromic display device having an electrochromic coloring layer with a more uniform thickness. The present invention relates to a method of manufacturing an electrochromic display device.

[Prior Art] In an electrochromic display device, an electrochromic coloring layer is generally formed by depositing [ITO (Indium
Tim Qxide).

A state in which the ITO film is used as a deposition electrode and the deposition electrode and the counter electrode are immersed in an electrolytic solution containing a material for forming an electrochromic coloring layer such as polyaniline, polythiolaene, polypyrrole, etc. And facing the deposition electrode l! Apply voltage between the poles,
A coloring layer forming process in which a film forming an electrochromic coloring layer is deposited and formed on a TO film, which is a deposition electrode, is carried out in order, for example, by electrolytic polymerization.

[Problems to be Solved by the Invention] In the above-mentioned ITO glass substrate, depending on the material forming the electrochromic coloring layer, the electrochromic coloring layer may not adhere uniformly, or even if it does adhere, it may be spotty. , it is not possible to form a uniform film required for electrochromic displays.

Therefore, in an electrochromic display device using an electrochromic cell using this ITO glass substrate as a display electrode, the display is not suitable, and it is difficult to display a large area.

Recently, in the ITO forming process, the applicant has heat-treated the ITo glass substrate under high vacuum at a temperature of 350 to 450°C to improve the uniformity of the IToil and thereby improve the electrochromic coloring layer. We have developed a manufacturing method that improves the uniformity of film thickness.

The present invention is a further advancement of the above manufacturing method, and an object of the present invention is to provide a method for manufacturing an electrochromic display device having a more uniform electrochromic coloring layer.

Means for Solving the Problems] The method for manufacturing an electrochromic display device of the present invention includes the following steps:
ITO ((ndium 7in) on the flat surface of the glass substrate
0xide)j! A heat treatment step in which the obtained ITOTO substrate is heated at a temperature of 350 to 450° C. for 2 to 4 hours under a vacuum of 10'' to 3 Torr or higher for 2 to 4 hours, and the heat treatment is performed. The ITO glass substrate was used as a deposition N1f, and the deposition electrode and counter electrode were immersed in an electrolyte containing aniline, thiophene, etc., and a voltage was applied between both electrodes to form an electrochromic coloring layer on the ITO glass substrate. rT
A method for manufacturing an electrochromic display device, comprising: a step of forming a coloring layer on the OII; The process is characterized in that the entire back surface of the ITo glass substrate is brought into surface contact with the flat portion.

In the above fTo formation step, IT is formed on the plane of the glass substrate.
This is a step of forming an O film. As a method for forming this [TO, a commonly used known method such as a vacuum evaporation method, a sputtering method, or an ion blasting method can be used. The thickness of the ITO film varies depending on the type of electrochromic display device, but is usually 1,000 to 1,000 mm.
There are about 4,000 people. In addition, as this glass substrate,
Those commonly used can be used.

The above heat treatment step is the most characteristic step in the present invention, and the obtained glass substrate is heated to a vacuum degree of 10-x7 orr.
The above was heated at a temperature of 350 to 450°C for 2 to 4 hours, and [T
This is a process to improve the uniformity of the O film.

If the degree of vacuum is less than 10''3 Torr, it is not preferable because the ITO may adhere unevenly or the ITO glass substrate may be colored. This is thought to be caused by the large amount of oxygen adhering to the glass substrate or the amount of oxygen in the atmosphere. Therefore, the degree of vacuum in the heat treatment step is preferably as high as possible. Usually, this degree of vacuum is 10-3 to 1
It is about 0-w1 Torr. The treatment temperature in the heat treatment step is 350 to 450°C. , less than 350℃ mF
G, t This is not preferable because the removal of oxygen and the like attached to the glass substrate becomes insufficient, and when the temperature exceeds 450°C, it is not preferable because the glass substrate becomes softened and deformed.

Further, the treatment time is determined in relation to the degree of vacuum or the treatment temperature, but is usually 2 to 4 hours, and is preferably as long as possible from the viewpoint of eliminating oxygen and the like.

In the heat treatment process, a metal mounting table with at least a part of the surface being flat is used, and the entire back surface of the 1-0 glass substrate located on the opposite side of the ITOIiJ is placed on the flat part of the metal mounting table. The mark is ¥# when done with the two surfaces in contact. The t/Lw stand generally has a wall thickness of 2 mm or more and is made of stainless steel.

The flat portion of the flat portion is desirably finished to be smooth so that the entire back surface of the ITO glass substrate makes good surface contact. In a special case, a liquid-permeable vibrator may be embedded in the mounting table. In the heat treatment process performed with the entire back surface of the ITO glass substrate in surface contact as described above, the heating and cooling of the ITO glass substrate during heat treatment is performed more uniformly, and therefore the temperature distribution of the ITO glass substrate is minimized. As a result, the uniformity of the ITO pattern on the ITO glass substrate is improved, and variations in electrical resistance from part to part of the fTo film are reduced.

In the coloring layer forming step, the ITo glass substrate subjected to the heat treatment step is used as a deposition electrode, and the deposition electrode and the counter electrode are immersed in an electrolytic solution containing thiophene, aniline, etc.
This is a step in which a voltage is applied between both electrodes, thereby forming an electrochromic coloring layer on the surface of the ITO glass substrate. In the coloring layer forming step, the deposition electrode is used as a positive electrode. When the material forming the electrochromic coloring layer is a conductive polymer such as polythiophene, polyaniline, polygorol, etc., electrolytic oxidative polymerization is used.

In this field oxidation polymerization, for example, an aqueous sulfuric acid solution containing aniline or the like is prepared as an electrolyte, and an ITO glass substrate and a counter electrode are immersed in this electrolyte.
The ITO glass substrate and the counter electrode are electrically connected via a lead wire so that the OIiJ side becomes the positive electrode, and a voltage of about several volts is applied to fT.

The voltage is applied between the glass substrate and the opposing north pole. Then, a polyaniline film of desired thickness is grown on the ITO film in a few seconds. This polyaniline film becomes an electrochromic coloring layer.

In addition, in the coloring layer forming step, when the material forming the electrochromic coloring layer is an inorganic material, for example, in Prussian blue, FeCff13 (68t
Using a mixed solution of 31"e (CN)s (D) and O) in equal amounts, the ITO glass substrate and the opposing i! electrode were immersed in this electrolyte, and a constant voltage of 10 to 40 μA/cm2 was applied between both electrodes. Applying a current, Fe'4 [Fe(CN)a] is deposited on the ten electrodes.
3e1MINl? put out

As mentioned above, since the variation in the electrical resistance of ITOIJ is reduced, the current distribution in the fTo film is uniform in the coloring layer forming step, and as a result, the electrochromic coloring layer is uniformly formed.

After passing through each of the above steps, an electrochromic display device is usually manufactured as follows. First, a spacer is placed on the peripheral edge side of the ITO glass substrate having the above-mentioned predetermined electrochromic coloring layer and another ITO glass substrate,
Their peripheries are sealed with an adhesive except for one location that will serve as an injection port, a predetermined electrolyte is injected between them from the injection port by vacuum injection, and the injection port is sealed. An electrochromic cell is manufactured in this manner, and then a predetermined electric circuit and the like are connected to manufacture the present display device.

[Effects of the Invention] The method for manufacturing an electrochromic display device of the present invention includes an ITO forming step of forming fTo on a glass substrate;
The exposed IT-0 glass substrate was placed in a vacuum of 10-3 Torr.
A heat treatment process in which heat treatment is performed by heating at a temperature of 350 to 450°C for 2 to 4 hours under the above vacuum, and an electrochromic color forming layer such as polyaniline is deposited on rTO glass using the heat treated rTO glass substrate as a deposition electrode. L of the board
OIt! and a coloring layer forming step of forming an electrochromic coloring layer on the glass substrate.The heat treatment step includes applying the [TO glass substrate It is characterized in that it is performed with the entire back surface in surface contact.

Therefore, according to the present gA manufacturing method, as described above, in the heat treatment process, the flat part of the mounting table allows the [T] to be formed.

The glass substrate is heated and cooled uniformly. Therefore, in the heat treatment process, the temperature distribution of the ITO glass substrate becomes uniform, and as a result, the uniformity of the ITO film on the To glass substrate is improved, and the uniformity of the electrical resistance in each part of the ITO film is improved. Therefore, in the coloring layer forming step, I
The TO film has improved uniformity as a deposition electrode, and electrolytic oxidation polymerization of aniline and the like can be uniformly performed, thereby making it possible to obtain a uniform electrochromic coloring layer.

Therefore, according to the present manufacturing method, it is possible to obtain an electrochromic display device with a more uniform display than in the past, and it is also possible to obtain an electrochromic display device with a large area.

[Example] The present invention will be explained below with reference to Examples.

(1) ITO formation process The fTo formation process was performed by a sputtering method.

The formation conditions for the sputtering method were as follows: 1 block 0 was used as a target, and the argon partial pressure was 10''''37orr.

The temperature of the glass substrate was 120°C. The thickness of the ITO glass plate 2 formed by sputtering method is 1 mm.
The l@thickness of rTO121 is 1000 angstroms.

(2) Heat treatment process Obtained IT″ formed by ion blating method
0 glass substrate 2 at a vacuum level of 10''''57orr, 450
Heat treatment is performed by heating at ℃ for 3 hours.

In this heat treatment process, as shown in FIG.
This is done with the entire back surface 20 of the device in surface contact. In the heat treatment step in which the entire back surface 20 of the ITO glass substrate 2 is in surface contact with the flat part 1o of the stainless steel mounting table 1, heating and cooling of the To glass substrate 2 during the heat treatment is more difficult. done evenly. Therefore, the temperature distribution during heat treatment of the ITO glass substrate 2 becomes as uniform as possible, and as a result, the uniformity of the r TO film 21 on the ITO glass substrate 2 improves, and the ITO! ! ! Variations in the electrical resistance of 21 from one part to another are reduced.

(3) Coloring layer forming step In the coloring layer forming step,
The ITO film 21 of the ITO glass substrate 2 was immersed as a deposition electrode in an electrolytic solution of +0.1 ML i BF4 )/7 setonitrile, and a counter N-electrode (not shown) was further immersed. Then, the rTO glass substrate 2 and the counter electrode are electrically connected via a lead wire (not shown) so that the fT (1!21 side, etc.) of the ITO glass substrate 2 becomes the positive electrode, and a voltage of about 5 volts is applied to the rTO glass substrate 2. A voltage was applied between the glass substrate 2 and the counter electrode.

Then, electrolytic oxidative polymerization takes place in a few seconds, and I
TO! A 0.2μ thick polythiophene film was grown on 21. The thickness of this polythiophene film is uniform,
This forms an electrochromic coloring layer. The state of the film formation is shown in FIG.

In FIG. 2, dotted areas indicate the polythiophene film, and white areas indicate the glass substrate 2.

In another example, the ITO formation process was performed as follows. Targeting ITO, argon partial pressure 10-3
It was formed by sputtering at a temperature of 250° C. and a glass substrate of Torr. Also in this case, the thickness of the ITO glass substrate 2 is 11II11, and the thickness of the ITO film 21 is 10II11.
00 angstroms. A polythiophene film with a uniform thickness was also formed on the TTO glass substrate formed in this other example.

In the comparative example, the rTO forming step and the coloring layer forming step were the same as in the above example. However, in the heat treatment process, as shown in FIG.
Do this in the same position.

In this placed state, the peripheral edge 70a of the back surface 70 of the ITO glass substrate 7 is in contact with the bridge portion 60 of the stainless steel mounting table 6. In the ITo formation process of the comparative example,
Heat treatment is carried out by heating at a temperature of 450° C. for 3 hours at an ITO glass plate combination 7 air pressure of 10 −5 Torr.

In the above-mentioned example, electrolytic oxidation polymerization was performed uniformly in the light emitting layer forming process, and 170 m2
A polythiophene film with a uniform thickness was formed on the i. Therefore, it is possible to obtain an electrochromic display device with a uniform display, and a large-area electrochromic display device! It became possible to make it a pole.

The reason is that during the heat treatment of the ITO glass substrate 2, the ITO
The uniformity of I21 of the glass substrate 2 is improved, and the ITO
This is thought to be because the variation in electrical resistance of 11!21 was reduced.

[Brief explanation of drawings]

FIG. 1 is a side view of the main parts of the heat treatment process of this example,
FIG. 2 is an explanatory diagram of an electrochromic coloring layer formed by electrolytic oxidation polymerization using an ITO glass substrate as a deposition electrode. FIG. 3 is a side view of the main part of the heat treatment process of the comparative example. Patent applicant Toyota Motor Corporation! ll vehicle co., Ltd. agent
Patent Attorney Hirodo Okawa Patent Attorney Akio Maruyama Figure 1 Figure 3 Figure 2

Claims (3)

[Claims] (1) Place ITO (IndiumTi) on the flat surface of the glass substrate.
The ITO forming process involves forming a (nOxide) film, and the resulting ITO glass substrate is heated to a vacuum level of 10^-^3 Torr.
A heat treatment step in which heat treatment is performed by heating at a temperature of 350 to 450 °C for 2 to 4 hours under a vacuum of r or more, and the ITO glass substrate that has been heat treated is used as a deposition electrode and is placed in an electrolytic solution containing aniline, thiophene, etc. An electrochromic device comprising a coloring layer forming step of immersing a deposition electrode and a counter electrode, applying a voltage between both electrodes, and forming an electrochromic coloring layer on the ITO film of the ITO glass substrate. A method for manufacturing a display device, wherein the heat treatment step is carried out with the entire back surface of the ITO glass substrate in surface contact with a flat portion of a metal mounting table, at least a portion of which is flat. A method for manufacturing an electrochromic display device, characterized in that: (2) The method for manufacturing an electrochromic display device according to claim 1, wherein the mounting table has a wall thickness of 2 mm or more and is made of stainless steel. (3) The method for manufacturing an electrochromic display device according to claim 1, wherein in the color forming layer forming step, the electrochromic color forming layer is formed by electrolytic oxidation polymerization of a conductive polymer.