JP2936186B2 - Method for manufacturing electrochromic device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electrochromic device.

[0002]

2. Description of the Related Art A phenomenon in which an electrolytic oxidation or reduction reaction occurs reversibly when a voltage is applied to cause reversible coloring is called electrochromism. Using an electrochromic (hereinafter abbreviated as EC) substance exhibiting such a phenomenon, an EC element (hereinafter abbreviated as ECD) that is turned on and off by a voltage operation is manufactured, and this ECD is used as a light amount control element (for example, Attempts to use it for an anti-glare mirror) and a numerical display element using 7 segments have been made for more than 20 years.
For example, an ECD (Japanese Patent Publication No. 52-46) in which a transparent electrode film (cathode), a tungsten trioxide thin film, an insulating film such as silicon dioxide, and an electrode film (anode) are sequentially laminated on a glass substrate.
098) is known as an all-solid-state ECD. When a voltage is applied to this ECD, tungsten trioxide (WO
₃ ) The thin film is colored blue. Thereafter, when a reverse voltage is applied to this ECD, the blue color of the WO ₃ thin film disappears and the WO ₃ thin film becomes colorless. Although the mechanism of coloring and decoloring is not elucidated in detail, it is understood that a small amount of water contained in the WO ₃ thin film and the insulating film (ion conductive layer) controls the coloring and decoloring of WO _3. Have been. The coloring reaction formula is estimated as follows.

Cathode side: H ₂ O → H ⁺ + OH ⁻ WO ₃ + nH ⁺ + ne ⁻ → HnWO ₃ (colorless and transparent) (blue) Anode side: OH ⁻ → 1 / 2H ₂ O + 1 / 4O ₂ ↑ + 1 / 2e ⁻ By the way, at least one of the pair of electrode layers which directly or indirectly sandwiches the EC layer must be transparent in order to make the discoloration of the EC layer visible to the outside. In particular, in the case of a transmissive ECD, both must be transparent. At present, SnO ₂ , In ₂ O ₃ , I
Although TO (mixture of SnO ₂ and In ₂ O ₃ ), ZnO, and the like are known, these materials have to be thin due to relatively poor transparency, and for this and other reasons, they are generally used. The ECD is formed on a substrate, for example, a glass plate or a plastic plate. FIG. 1 shows an example of the structure of such an ECD.

FIG. 1A shows an upper transparent electrode,
(B) is a lower transparent electrode, (E) is a reduction coloring EC layer (for example, WO ₃ ), (D) is an ion conductive layer, and (C) is a reversible electrolytic oxidation layer or an oxidation coloring EC layer (for example, oxidation). Or iridium hydroxide), and the ECD is basically composed only of the laminated structure of (A) and (B). As described above, these ECDs are formed on the substrate (S). .

[0005]

However, the conventional method for manufacturing an electrochromic device has a problem that when the EC material layer is formed by a sputtering method, the glass substrate is easily cracked and the plastic substrate is easily deformed. Was. This problem is particularly likely to occur in a sputtering apparatus that cannot cool the substrate. In addition, when the input power is increased to increase the deposition rate, there is a problem that the metal oxide target is easily broken.

An object of the present invention is to improve the film forming rate without causing the above problem.

[0007]

Means for Solving the Problems In the conventional method for manufacturing an EC device, an EC material layer is formed by a high-frequency sputtering method using a metal oxide target having stable discharge. The present inventors have studied that, in the high-frequency sputtering method of a metal oxide target, when the deposition rate is increased, the temperature of the substrate is significantly increased due to radiant heat, so that the glass substrate is easily cracked and the plastic substrate is easily deformed. I understand. The inventors have found that the above-mentioned problem does not occur even if the deposition rate is increased by forming the EC material layer by a reactive DC sputtering method using a metal target, and the present invention has been accomplished.

Accordingly, the present invention provides a method for manufacturing an electrochromic device comprising a pair of transparent electrode layers, an electrochromic material layer and an ion conductive layer, one or both of which are formed of an argon gas and an oxygen gas. And a method for producing an electrochromic device characterized in that the film is formed by a reactive direct current sputtering method.

Further, it is preferable that the electrochromic material layer is made of tungsten oxide.
Furthermore, the range of the partial pressure of oxygen gas when forming the EC material layer by the reactive DC sputtering method is from 1 × 10 ^-4 torr to 8%.
It is preferably × 10 ⁻³ torr (claim 3).

[0010]

When the EC material layer is formed by a reactive DC sputtering method using a metal target, even if the film formation rate is increased, the substrate temperature rise due to radiant heat is small, and the glass substrate is not easily cracked or the plastic substrate is hardly deformed. Also, even if the input power is increased, the target does not easily break. Therefore, the film formation rate can be sufficiently increased as compared with the high frequency sputtering method for a metal oxide target.

In the reactive DC sputtering method for a metal target, discharge tends to be unstable as compared with the high frequency sputtering method for a metal oxide target, but this is not a problem in the embodiment of the present invention. . The laminated structure of the ECD in the present invention is not particularly limited, but the structure of the solid-type ECD is, for example, a four-layer structure such as an electrode layer / EC layer / ion conductive layer / electrode layer; A five-layer structure such as a reduction coloring type EC layer / an ion conductive layer / a reversible electrolytic oxidation layer is exemplified.

As a material of the transparent electrode, for example, Sn
O ₂ , In ₂ O ₃ , ITO and the like are used. Such an electrode layer is generally formed by vacuum deposition, ion plating,
The film is formed by a vacuum thin film forming technique such as sputtering.
WO ₃ , MoO _{3 and the} like are generally used as the reductive coloring EC layer. As the ion conductive layer, for example, silicon oxide, tantalum oxide, titanium oxide, aluminum oxide,
Niobium oxide, zirconium oxide, hafnium oxide, lanthanum oxide, magnesium fluoride and the like are used. These material thin films are insulators for electrons, but are good conductors for protons (H ⁺ ) and hydroxy ions (OH ⁻ ). A cation is required for the color-decoloring reaction of the EC layer, and it is necessary to include H ⁺ ions and Li ⁺ ions in the EC layer and the like. The H ⁺ ion does not need to be an ion from the beginning, and it is sufficient that H ⁺ ion is generated when a voltage is applied. Therefore, water may be contained instead of the H ⁺ ion. This water is very small and sufficient, and often discolors even with water that naturally enters from the atmosphere.

[0013] Either the EC layer or the ion conductive layer may be on the upper side or the lower side. Further, a reversible electrolytic oxidation layer or a catalyst layer may be provided between the EC layer and the ion conductive layer (which may be an oxidative coloring EC layer in some cases).
Examples of such a layer include iridium oxide or hydroxide, vanadium, ruthenium, and rhodium. These substances may be dispersed in the ionic conduction layer or the transparent electrode, or they may be dispersed. The opaque electrode layer may also be used as the reflection layer, and for example, a metal such as gold, silver, aluminum, chromium, tin, zinc, nickel, ruthenium, rhodium, and stainless steel is used.

When tungsten oxide is used as the EC material layer, an EC element having good characteristics is easily obtained. The tungsten oxide thin film layer can be easily formed by a sputtering method. When the tungsten oxide thin film layer is formed by a reactive DC sputtering method using a metal target and the partial pressure of oxygen gas is set to 1 × 10 ⁻⁴ torr to 8 × 10 ⁻³ torr, discharge is relatively stable. In addition, the film formation rate can be increased without causing problems such as cracking of the glass substrate and deformation of the plastic substrate due to an increase in the substrate temperature.

If the oxygen gas partial pressure is less than 1 × 10 ⁻⁴ torr, there is a problem that a tungsten oxide film having a large absorption and a low transmittance or a film close to a metal is easily formed. Also 8 × 1
If it exceeds 0 ^-3 torr, there is a problem that discharge becomes unstable and a uniform film cannot be obtained. Hereinafter, the present invention will be described specifically with reference to examples.

[0016]

EXAMPLE An ITO electrode layer was formed on the entire surface of a rectangular glass or plastic element substrate (S), and then an extraction electrode layer (F) for an upper electrode (A) was formed by photoetching or laser cutting. A groove was formed between the lower electrode layer (B). Thus, a take-out portion (F) and a rectangular lower electrode (B) isolated therefrom were formed. Note that these patterns may be formed directly by depositing ITO using a mask.

Next, a reversible electrolytic oxide layer (C) comprising a mixture of iridium oxide and tin oxide and an ion conductive layer (D)
Is sequentially formed, and then tungsten oxide as the EC material layer (E) is formed by a reactive DC sputtering method using a tungsten metal target.
The film forming conditions at this time are shown below. Ultimate vacuum: 3 × 10 ⁻⁶ torr Sputter gas pressure: 1 × 10 ⁻² torr (Ar, O ₂ ) Oxygen gas partial pressure: 2 × 10 ⁻³ torr Film formation rate: 240 ° / min Finally, the upper electrode ( A) Forming ITO layer as EC
D was manufactured. At this time, the ITO was formed such that one end thereof was in contact with the take-out portion (F) already formed on the substrate (S).

Here, two conductive clips (H) made of phosphor bronze having a U-shaped cross section were prepared. This clip (H)
Two of them were mounted on the short side of the element substrate (S), respectively, so that the clip (H) crimped the upper and lower electrode extraction portions (see FIG. 2). The shape and dimensions of the conductive clip (H) were set so that positioning of the sealing substrate (G) and masking of a non-display portion around the ECD could be performed.

Thereafter, the element is sealed with an epoxy resin (R) and a sealing substrate (G) made of glass or plastic. Then, when the external wirings L _A and L _B are bonded to the two conductive clips (H) attached to the extraction portions of the upper electrode and the lower electrode, the ECD of this embodiment is completed. This is the ECD shown in FIG. This EC
When a coloring voltage (+1.35 V) is applied to D from the driving power supply (Su), the transmittance for light having a wavelength of 633 nm incident on the substrate is reduced to 20% (after 10 seconds), and the transmittance is determined by applying a voltage. Stopped for a while. This time, the decoloring voltage (-
When 1.35 V) was applied, the transmittance was restored to 70% (after 10 seconds).

[Comparative Example] Except that the tungsten oxide, which is the EC material layer of the embodiment, was formed by a high-frequency sputtering method using a tungsten oxide target, E was used.
A C element was manufactured. The conditions for forming the tungsten oxide layer at this time are shown below. Ultimate vacuum: 3 × 10 ⁻⁶ torr Sputter gas pressure: 1 × 10 ⁻² torr (Ar gas only) Film formation rate: 100 ° / min. If the film formation rate is further increased, the glass substrate is broken or the plastic substrate is deformed. As a result, the device could not be manufactured. In addition, cracks easily occurred on the target surface.

[0021]

As described above, according to the present invention, since the EC material layer is formed by the reactive DC sputtering method of the metal target, even if the film formation rate is increased, the substrate temperature rise due to radiant heat is small, and Cracks and deformation of the plastic substrate hardly occur. Also, even if the input power is increased, the target does not easily break. Therefore, the film formation rate can be sufficiently increased as compared with the high frequency sputtering method for a metal oxide target.

When the EC material layer is made of tungsten oxide, a film can be easily formed by a reactive DC sputtering method using a metal target, and an element having good characteristics can be easily obtained. Further, in forming the tungsten oxide layer, by setting the range of the partial pressure of oxygen gas to 1 × 10 ⁻⁴ torr to 8 × 10 ⁻³ torr, a uniform film with high transmittance can be stably obtained.

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional view of an ECD according to an embodiment of the present invention.

FIG. 2 is a schematic vertical sectional view of an ECD in the course of manufacturing according to the embodiment.

[Description of Signs of Main Parts]

A top electrode B lower electrode E WO ₃ layer or reductive coloring EC layer D ion Yoshirubeso C reversible electrolytic oxidation layer ECD electrochromic device (laminated structure) S element substrate G sealing substrate R sealing resin H conductive clip

Claims (3)

(57) [Claims] 1. A method for manufacturing an electrochromic device comprising a pair of electrode layers, one or both of which is transparent, an electrochromic material layer, and an ion conductive layer,
A method for manufacturing an electrochromic device, wherein the electrochromic material layer is formed by a reactive DC sputtering method using an argon gas and an oxygen gas. 2. The method according to claim 1, wherein the electrochromic material layer is made of tungsten oxide. 3. The electrochromic according to claim 2, wherein the range of the oxygen gas partial pressure in the reactive DC sputtering method is from 1 × 10 ⁻⁴ torr to 8 × 10 ⁻³ torr. Device manufacturing method.