JPS60150034A - Electrochromic element - Google Patents

Abstract

PURPOSE:To improve transparency, response speed, etc. by using a thin film formed by sputtering iridium in the presence of gaseous oxygen having a high gaseous pressure and (or) steam as an oxidation coloring layer. CONSTITUTION:An electrochromic element is formed by forming successively an electrode 12 (e.g.; indium oxide, tin oxide), a reduction coloring layer 13 (e.g.; tungsten dioxide layer, molybdenum dioxide layer), an intermediate layer 14 (e.g.; zirconium dioxide layer, silicon dioxide layer), an oxidation coloring layer 15 and an electrode 16 on a substrate 11. The intended electrochromic element is obtd. in this stage by using the thin film of iridium oxide or the thin film of iridium hydroxide formed by sputtering iridium in the presence of gaseous oxygen having >=0.1 gaseous pressure and (or) steam as the layer 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thin film laminated electrochromic device (hereinafter referred to as rECDJ5), and specifically relates to a j13cD using an oxidized coloring layer with improved transparency. .

ECD can be applied to, for example, numeric display elements, X-Y matrix display elements, optical shutters, aperture mechanisms, etc. For example, an RC with an all-solid thin film laminated structure shown in Fig.
D is known. That is, the ECD shown in FIG.
A reduction coloring layer 16 and an intermediate layer 14 are provided between the pair of electrodes 12 and 16.
A thin film laminated structure of a color forming layer 15 and an oxidized color forming layer 15 is arranged. In this ECD, an optical change between a colored state and a decolored state is obtained by a reversible electrochemical reaction. For example, the electrode 12 on the side of the reduction coloring layer 16 has a negative polarity, and the electrode 1 on the side of the oxidation coloring layer 15 has a negative polarity.
By applying a voltage with a positive polarity to 6, the reduction coloring layer 16 and the oxidation coloring layer 15 can be brought into a colored state, and by making the polarities of these voltages opposite to each other, the colored state can be changed from a colored state to a decolored state. Optical changes can be made to the state.

By the way, U.S. Patent No. 4,191,453 proposes that iridium oxide can be used as an anode material for ECD that develops color through an anode reaction, and Japanese Patent Application Laid-Open No. 56-4
Japanese Patent No. 679 proposes an ECD in which iridium oxide is applied as an oxidized coloring layer of the above-mentioned all-solid-state thin film laminated type ECD.

However, such conventionally used iridium oxide oxidation coloring layers have drawbacks such as slow response speed and low transmittance, and do not have sufficient performance in practical terms.For this reason, for example, As described in U.S. Pat. No. 4,258.984, a thin film of iridium oxide or a thin film of metallic iridium formed by sputtering is anodized in an aqueous sulfuric acid solution by low frequency driving. A method has been proposed to overcome this drawback, but the transmittance of the iridium oxide thin film formed by this method is at most about 70° or more, and it does not have sufficient transparency. It is not suitable because it causes pinholes at 4 o'clock when creating the iridium oxide thin film.Furthermore, the iridium oxide thin film produced by reactive sputtering also cannot obtain a highly transparent film, and has a sufficient EC. In order to obtain the characteristics (reversible electrochemical reaction characteristics), it is necessary to subject this iridium oxide thin film to the aforementioned anodic oxidation treatment.

The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problems that occurred when applying an iridium oxide thin film as an oxidized coloring layer of an ECD, and found that, in particular, oxidation using reactive sputtering We have discovered that the reaction gas pressure when forming a thin film of iridium or iridium hydroxide has a causal relationship with the transmittance characteristics of the thin film.

Therefore, the object of the present invention is to use iridium oxide (1rox; 0.5<x2, preferably 1<x2) or iridium hydroxide (1rox; 0.5<x2) or iridium hydroxide (1rox;
An object of the present invention is to provide an ECD provided with a thin film of r(OH)n; n <2.

That is, the present invention provides 1rO by reactive sputtering.
zl1g or 1r(OH)n When forming the film, the reaction gas (oxygen gas) pressure is Q, which is higher than the conventional 10-8 TOrr, preferably 0.1 Torr or more.
It is characterized in that it is 1 Torr to 1'rorr, and as a result, it is possible to provide an ECD having good EC characteristics and an oxidized color forming layer with high transmittance. Moreover, the oxidized coloring layer according to the present invention has an appropriate porous surface state that can cause a sufficiently reversible electrochemical reaction, and can provide an ECD with a fast response speed.

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

The RCD of the present invention can use the thin film laminated structure shown in FIG.
Omata, which is provided with an Ox film or a 1r(OH)n film,
The reduction coloring layer 13 in the figure can also be omitted.

Examples of the reduction coloring layer 13 that can be used in the ECD of the present invention include tungsten dioxide (Wow), tungsten trioxide (Woe), and molybdenum dioxide (M).

A thin film of molybdenum trioxide (Mo5s), vanadium pentoxide (VgOs), or the like can be used.

Intermediate layer 14Fi, zircon dioxide (ZrOt), r
Silicon oxide (SiO, Ri, Silicon dioxide (Sing)
, oxides such as tantalum pentoxide (Ta*Os), lithium fluoride (''), magnesium fluoride (M
This is an insulating film made of a dielectric material such as fluoride (gFs).

Such oxidation coloring layer 15/intermediate layer 14/reduction coloring layer 13
A reversibly electrochemically reactive structure consisting of is sandwiched between electrodes 12 and 16, with electrode 12 being supported by substrate 11. This base 11 is generally formed of a glass plate, but it is not limited to a glass plate, and a plastic plate can also be used.
It may be provided on either side, or it may be provided on both sides depending on the purpose (for example, as a protective cover). In addition, the electrodes 12 and 16 may be made of indium oxide, tin oxide or IT.
A transparent conductive film such as O (Indium Tin Oxiee) can be used, but if necessary, one of the electrodes 12 and 16 can be made of a suitable metal film.

The oxidized coloring layer 15 used in the present invention is shown in FIG.
z or 1r(0)1)n It can be formed using a sputtering device for forming thin films.

The sputtering equipment shown in FIG.
In the figure, two deposition objects 202a and 202b are arranged)
, metal iridium (1r) as a target, and a pallet 206 are placed at predetermined positions, and the object to be evaporated 20
It is supported by a support body 205 that is cooled by two cooling water circulation pipes 204, and the object to be deposited can be kept at about room temperature during sputtering. Further, the metal iridium pallet 206 is placed on the electrode body 206 (made of stainless steel or the like). Further, instead of this metal iridium pallet 206, other iridium such as iridium oxide or iridium hydroxide may be used. This electrode body 206 is connected to a matching box 208 connected to a high frequency power source 207.

Further, the vacuum chamber 21 is connected to an oxygen gas cylinder 209 for introducing oxygen gas as a reaction gas and a vacuum pump 310, respectively, and valves 311 and 312 are attached to each of them.

When forming 1rO,riQ, which is the oxidized color forming layer of the present invention, the inside of the vacuum chamber 201 is brought to a vacuum state (10 Torr) by operating the vacuum pump 610, and then the valve 312 is closed to maintain the vacuum state. After that, open the valve 311 and turn on the oxygen gas cylinder 209.
Oxygen gas is introduced into the C empty tank 201, and the gas pressure is 3.1'l"orr or more, preferably 0.1TOrr.
〜1 TOrr. After that, high frequency power (frequency 13.56 MHz; power 1 w76 J or less, preferably 0.4 w/cJ or less) is applied to the electrode body 206,
By generating a glow discharge and performing sputtering, a 1roz film can be formed on the deposited bodies 202a and 202b. Ir0r formed at this time
l[ can effectively function as an oxidized coloring layer of a general ECD.

Figure 3 shows the transmittance of a 350A Ir1s film for a helium-neon laser with an oscillation wavelength of 633nm and a 0.2WA
The relationship between Q
, Q5Torr, Q,1Torr, Q,2Torr
Using a helium-neon laser, we measured the transmittance of a 650A IrOx film formed when the pressure was set to rr, Q, and Torr, and found that the transmittance was sufficiently high when the oxygen gas pressure was set to 0.1 Torr or higher. 1rOgg
It turns out that you can get . Further, the upper limit of the mixed gas pressure should be set to a value that allows uniform glow discharge to occur.

In addition, the 1r(OH)n film can be formed by using water vapor instead of oxygen gas during the sputtering described above, and a mixed gas of oxygen gas and water vapor can also be used. The same effect can be obtained.

In addition to the previous sputtering device used to form the oxidized color forming layer of the present invention, reactive high frequency ion 7'V-
It is possible to use the irradiation method or the reactive arc discharge ion blating method, and the same effects as described above can be obtained in this case as well.

The 1rOx film obtained by conventional sputtering has poor permeability, and a high-quality film cannot be obtained without post-treatment such as anodic oxidation. This is because, as is clear from FIG. 6, the film was formed at a low gas level (approximately 10-8 Torr or less).

It is true that increasing the gas pressure increases the permeability of the membrane, but when used as an oxidized color forming layer of an ECD, an ECD with a fast response speed can be obtained.

Hereinafter, the present invention will be explained according to examples.

Example 1 0,8+++ with 1TO film provided! A glass substrate of '11 and metallic iridium were prepared, and each was attached to a sputtering apparatus shown in Figure 2. After that, the air in the vacuum chamber of the sputtering equipment is evacuated using a vacuum pump, and the air is pumped out.
Introduce oxygen gas into the vacuum chamber from the ji2 gas introduction pipe,
The oxygen gas pressure was set at 0.2 Torr. Next, a high frequency wave of 13.56 MHz was applied to the electrode body under a power of 0.2 yen, and sputtering was performed for about 1 hour.
A 35OA lr film was formed on the To crotch.

On top of this film, a 300% Ta5ks film is deposited by vacuum evaporation method.
The degree of vacuum at this time was 1d2.1x10, provided with a film thickness of OA.
Torr, vapor deposition speed return was 8 A/see. Furthermore, a WOs film, which will become a reduction coloring layer, was formed on this film to a thickness of 4000 A using a vacuum evaporation method, and a translucent Am
The membrane was provided with a thickness of 3001 mm.

The ECD thus prepared had the same transparency compared to the conventional one. Furthermore, this BCD electrode (
A DC voltage of 2.2 V (
When the ITO14 electrode was set to positive polarity and the translucent membrane was set to negative polarity), it changed to a colored state with an extremely fast response speed. Next, when the supply of voltage was stopped, this colored state was maintained, and when a DC voltage of 2.2 μm was further applied with the opposite polarity to the above-mentioned polarity, an optical change occurred from a 1 colored state to a decolored state. occurred.

Example 2 An ECD was prepared in the same manner as in Example 1 except that water vapor was used instead of the oxygen gas used in Example 1, and when it was further evaluated, the same results as in Example 1 were obtained. was gotten.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an electrochromic confectionery. FIG. 2 is a sectional view schematically showing the sputtering apparatus used in the present invention. Figure 6 shows gas pressure and 1rOx:
FIG. 2 is an explanatory diagram showing the relationship between light and transmittance. 11; Substrate 12.16-; %L 16: Reduction coloring layer 14: Intermediate J- 15 Dioxide coloring layer 201; Vacuum chamber 202; Cover @adherent 203; Metal iridium pallet 204; Cooling water circulation pipe 205; Support 206; Electrode 207; High frequency power supply 208; Matching box 209; Acid gas cylinder 610; Vacuum pumps 311, 312; Valves

Claims (2)

[Claims] (1) In an electrochromic device having an oxidized coloring layer between a pair of electrodes, the oxidized coloring layer is formed by sputtering iridium in the presence of oxygen gas and/or water vapor having a gas pressure of 0.1 or more. An electrochromic element characterized by being a formed thin film. (2) The electrochromic device according to claim 1, wherein the iridium is metallic iridium.