JPH10197905A - Electrochromic layer and electrochromic device using the same - Google Patents

Abstract

(57) [Problem] To improve the color erasing / decoloring speed of an electrochromic layer composed of WO ₃ to which M ₀ O ₃ is added. SOLUTION: Six layers of thin films 11 to 16 are formed on a transparent glass substrate.
Are laminated. The electrochromic layer 15, which is the fifth layer, is a mixture of WO ₃ and MO ₃ and MgO or at least one of ZrO ₂ , Y ₂ O ₃ and Al ₂ O ₃ and MgO are added. , M ₀ O ₃ is sufficient for ND conversion, and it has the same coloration and erasing speed as that of WO ₃ alone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrochromic layer (EC layer) having a reduced coloring property for use in a display element, a variable transmittance filter of a video or a camera, and an electrochromic element (EC element) using the same. ).

[0002]

2. Description of the Related Art An electrochromic device (EC device) which performs color erasing and decoloring by applying a voltage has a higher transmittance at the time of erasing than a liquid crystal device, has a memory property, and has a polarization property. Since it has an excellent characteristic of being unaffected, it is expected to have great potential in a wide range of fields such as display elements replacing liquid crystal elements, and variable transmittance filters for videos, cameras and the like.

[0003] In a general EC element, a WO ₃ film is used as an electrochromic layer (EC layer) having a reduction coloring property. The coloring reaction of an electrochromic layer containing WO ₃ as a base material is represented by the following equation.

WO ₃ (decolored) + xe ⁻ + xH ⁺ ← → HxWO ₃ (colored) (1) However, the reaction represented by the formula (1) causes WO ₃
Since the film changes from transparent to blue, there is no problem when used as a display element, but when used as a variable transmittance filter for video or cameras, color reproducibility and color balance are impaired. Therefore, the blue coloring of the WO ₃ film is changed to ND (N
(e.g., E.O.D.Eutral Density)
A technique for adding ₃ has been developed (see US Pat. No. 4,099,935).

[0005]

[SUMMARY OF THE INVENTION However, according to the prior art, reductive coloring electrochromic layer with the addition of MoO ₃ to the WO ₃ as described above, the wear decoloring speed, WO ₃ only There is an unsolved problem that it is reduced by 30 to 50% as compared with the case. The degree to which the color erasing speed decreases as described above is determined by the mixing ratio of WO ₃ and MoO _3.
It is presumed that this is because the addition of oO ₃ increases the ionic conductivity of the electrochromic layer having reduced color development.

[0006] Japanese Patent Application Laid-Open No. 55-6000 discloses that
P ₂ O is added to an electrochromic layer composed of only WO ₃ or an electrochromic layer obtained by adding MoO ₃ to WO _3.
5 , B ₂ O ₃ , Al ₂ O ₃ , SiO ₂ , As ₂ O ₃ , S
A method of increasing the crystallization resistance by adding b ₂ O ₃ , GeO ₂ or a mixture thereof has also been disclosed, but the problem that the addition and removal of MoO ₃ to WO ₃ results in a reduction in the color erasing / discoloring speed. It does not solve the point directly and effectively.

The present invention has been made in view of the above-mentioned unsolved problems of the prior art, and has greatly improved the color erasing / discharging speed when M ₀ O ₃ for ND formation is added to WO _3. It is an object of the present invention to provide an electrochromic layer that can be formed and an electrochromic element using the same.

[0008]

In order to achieve the above object, the electrochromic layer of the present invention comprises WO ₃ and M
_An electrochromic layer containing a mixture of O ₃ as a main component, characterized in that MgO is added as an additive for increasing the color erasing / decoloring speed.

An electrochromic layer mainly composed of a mixture of WO ₃ and M ₀ O ₃ , wherein ZrO ₂ , Y ₂ O ₃ and A are used as additives for increasing the color erasing / decoloring speed.
At least one of l ₂ O ₃ and MgO may be added.

The amount of the additive is preferably in the range of 10 to 1000 ppm by weight based on the mixture of WO ₃ and M ₀ O ₃ .

The weight ratio of WO ₃ to M ₀ O _{3 in} the mixture is 9
It is good to be in the range of 5: 5 to 80:20.

[0012]

SUMMARY OF electrochromic layer of a mixture of M ₀ O ₃ for ND into WO _3, as compared to those based only WO _3, tends to Chakushoiro speed decreases to 30-50% Therefore, an electrochromic device having excellent responsiveness cannot be obtained. Therefore, MgO or at least one of ZrO ₂ , Y ₂ O and Al ₂ O ₃ and MgO are added as additives to improve the color erasing and erasing speed of the electrochromic layer. These additives are metal oxides other than hexavalent, and are presumed to function to suppress the increase in the ionic conductivity of the electrochromic layer having reduced coloring and to increase the color erasing / discharging speed.

By using an electrochromic layer to which such an additive is added, a high-quality electrochromic device having excellent responsiveness can be obtained.

[0014]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an electrochromic device according to one embodiment. In this method, a first transparent conductive layer (ITO film made of indium oxide and tin oxide) 11 is formed as a first layer on the surface of a transparent glass substrate 10 as a base by vacuum evaporation or the like, and as a second layer, An electrochromic layer 12 having an oxidative coloring property is laminated by a high frequency sputtering method or the like targeting a metal Ir, and a metal I
mixed layer 13 of Ir (hydr) oxide and SnO ₂ by a binary high frequency sputtering method or the like targeting r and metal Sn.
To form a fourth layer of Ta ₂ O ₅ by vacuum evaporation.
A transparent ion conductive layer 14 composed of a film is laminated, and as a fifth layer, an evaporation source obtained by adding MgO as an additive to a raw material of an electrochromic layer composed of a mixture of WO ₃ and MoO ₃ as a main component by an electron gun. Electrochromic layer 1 having reduced coloring by heating and evaporating by vacuum evaporation
5 and a second transparent conductive layer (I) is formed as a sixth layer by high-frequency ion plating using an ITO sintered body.
This is an electrochromic element having a six-layer structure composed of six thin films in which TO layers (TO film) 16 are laminated. After the sixth layer is laminated, the entire resin is sealed.

The electrochromic element having such a film structure has the same coloration and erasing speed as the case where the electrochromic layer composed of only WO ₃ is used as the fifth layer, and is obtained by adding MoO _3. ND conversion is also sufficient.

The metal oxide (Mg) mixed into the electrochromic layer 15 having a reduced coloring property constituting the fifth layer.
The content of O) is in the range of weight ratio 10~1000ppm against the raw material is a mixture of WO ₃ and MoO _3, the weight ratio of WO ₃ and MoO ₃ raw materials 95: 5 to 80:20 It is desirable to be within the range.

Further, the additive is not limited to MgO alone.
l ₂ O ₃ , ZrO ₂ , Y ₂ O ₃ or a mixture of these metal oxides may be used in combination with MgO. By adding a metal oxide other than hexavalent in this way, WO by adding MoO ₃ for ND formation is improved.
It is presumed that the increase in ionic conductivity of No. ₃ was effectively suppressed, and the speed of coloration and decoloration of the electrochromic layer was improved.

The content of the metal oxide is 10 to 100.
Since it is as small as 0 ppm, it does not adversely affect other performances of the electrochromic device. If it is less than 10 ppm, the effect of improving the color erasing / decoloring speed is insufficient, and
If it exceeds 00 ppm, the effect of improving the color erasing speed will be reduced.

The most effective combination of the metal oxides is MgO and Al ₂ O ₃ .

As described above, the weight ratio of WO ₃ to MoO ₃ is preferably from 95: 5 to 80:20 in terms of ND and transmittance. When the weight ratio of WO ₃ to MoO ₃ is 95: 5 or less, the blue component of WO ₃ is large during coloring and ND conversion is insufficient. When the weight ratio is 80:20 or more, the absorption of MoO ₃ increases and the transmittance decreases. .

When the above-mentioned metal oxide is contained in a reduction color-forming electrochromic layer using a mixture of WO ₃ and MoO ₃ , as described above, when vacuum deposition using an electron gun is employed, an additive may be used. The melting point of certain MgO is 280
0 ° C., the melting point of ZrO ₂ is 2720 ° C., the melting point of Y ₂ O ₃ is 2410 ° C., and the melting point of Al ₂ O ₃ is 2030 ° C. Therefore, WO ₃ (boiling point 1840 ° C.) which is a sublimable substance and M
Since it is higher than oO ₃ (boiling point 1155 ° C.), the content of the metal oxide in the evaporation source needs to be limited to 1 to 5% by weight based on the mixture of WO ₃ and MoO ₃ .

It should be noted that instead of vacuum evaporation, sputtering,
Ion plating, a CVD method, a sol-gel method, or the like may be employed.

[0024]

【Example】

(Example 1) ITO as a first layer on a transparent glass substrate
Substrate temperature = 3 by vacuum evaporation using a sintered body as an evaporation source
A transparent conductive layer having a thickness of 150 nm is formed at 00 ° C. and a partial pressure of O ₂ = 5 × 10 ⁻² Pa.

As a second layer, an oxidative and coloring electrochromic layer having a film thickness of 5 nm is deposited at a substrate temperature of room temperature, an O ₂ partial pressure of 1 Pa, and a high-frequency sputtering method using metal Ir as a target.

As the third layer, a substrate temperature = room temperature, a water vapor partial pressure = 1 Pa, and a film thickness of 25 n were obtained by a binary high frequency sputtering method using a metal Ir target and a metal Sn target.
A mixed layer of m (Ir) oxide and SnO ₂ is laminated.

As the fourth layer, a substrate temperature = 300 ° C., an O ₂ partial pressure = 3 by vacuum evaporation using Ta ₂ O ₅ as an evaporation source.
A transparent ion conductive layer having a thickness of 300 nm and a thickness of 10 ⁻² Pa is laminated.

As the fifth layer, WO ₃ , MoO _3, and MgO
And a mixture of Al ₂ O ₃ (weight ratio: WO ₃ / MoO ₃ / M
gO / Al ₂ O ₃ = 90/10 / 2.5 / 1), and the substrate temperature was 3 by vacuum evaporation using an electron gun.
Thickness 1000 nm at 00 ° C., O ₂ partial pressure = 5 × 10 ⁻² Pa
Are laminated. The substrate on which only the fifth layer was formed was dissolved in nitric acid and hydrofluoric acid, and Mg and Al were quantified by atomic absorption analysis.
The weight ratio was 80 ppm and 30 ppm in terms of oxide, respectively, of the mixture of WO ₃ and MoO ₃ .

Next, as a sixth layer, a substrate temperature = 300 ° C., an O ₂ partial pressure = 5 by high-frequency ion plating.
× 10 ^-2 Pa, high frequency power = 150 W and film thickness 300 n
m of a transparent conductive layer (ITO film). After the thus obtained electrochromic element having a six-layer structure is sealed with a resin, the electrodes are -2, +1, +1.25 and +1.
When a voltage of 75 V was applied and the spectral transmittance at a wavelength of 400 to 700 nm was measured, as shown in FIG.
It has been found that the device is an electrochromic device having simplified spectral characteristics.

When the color erasing / decoloring speed was measured, the fifth
The layer was equivalent to WO ₃ = 100%.

(Example 2) A mixture of WO ₃ , MoO ₃ , MgO and Al ₂ O ₃ (weight ratio: WO ₃ / MoO) of the fifth layer
_{3 / MgO / Al 2 O 3} = 90/10 / 2.5 / 1)
Was manufactured in the same manner as in Example 1 except that Al ₂ O ₃ was changed to ZrO ₂ or Y ₂ O ₃ , and after sealing with a resin, the colored state was measured. The same spectral characteristics as in Example 1 were obtained.

When the color erasing / decoloring speed was measured, the fifth
It was only ₂ % lower in the case of ZrO ₂ and 3% lower in the case of Y ₂ O ₃ than the case where the layer had WO ₃ = 100%.

The substrate on which only the fifth layer is formed is dissolved in nitric acid and hydrofluoric acid, and Mg and Zr, Y are analyzed by atomic absorption analysis.
Was determined, and the weight ratio was 80 ppm in terms of oxide with respect to the mixture of WO ₃ and MoO ₃ , respectively.
And 28 and 30 ppm.

Example ₃ A mixture of WO ₃ , MoO ₃ , MgO and Al ₂ O ₃ (weight ratio: WO ₃ / MoO) in the fifth layer
_{3 / MgO / Al 2 O 3} = 90/10 / 2.5 / 1)
And the _{Al 2 O 3 Al 2 O 3} , ZrO 2, Y 2 2 kinds or more of O ₃ (mixing ratio: 1) except for changing the, manufacture an electrochromic device in the same manner as in Example 1 Then, after sealing with resin, the coloring state was measured, and the same spectral characteristics as in Example 1 were obtained.

When the color erasing / decoloring speed was measured, the fifth
The layer was equivalent to WO ₃ = 100%.

Example 4 A mixture of WO ₃ , MoO ₃ , MgO and Al ₂ O ₃ in the fifth layer (weight ratio: WO ₃ / MoO)
_{3 / MgO / Al 2 O 3} = 90/10 / 2.5 / 1)
With a mixture of WO ₃ , MoO ₃ and MgO (weight ratio: WO
₃ / MoO ₃ /MgO=90/10/2.5) except that the electrochromic element was manufactured in the same manner as in Example 1, and after sealing with resin, the colored state was measured. The same spectral characteristics as in Example 1 were obtained.

When the color erasing speed was measured, the fifth
It was only 5% lower than the one with WO ₃ = 100%.

Example 5 A mixture of WO ₃ , MoO ₃ , MgO and Al ₂ O ₃ in the fifth layer (weight ratio: WO ₃ / MoO)
₃ / MgO / Al ₂ O ₃ = 90/10 / 2.5 / 1), except that the weight ratio was changed to 90/10/7/7, to manufacture an electroclinic element in the same manner as in Example 1. And
After sealing with resin, the colored state was measured, and the same spectral characteristics as in Example 1 were obtained.

When the color erasing speed was measured, the fifth
It was only 1% lower than the one with WO ₃ = 100%.

When the substrate on which only the fifth layer was formed was dissolved in nitric acid and hydrofluoric acid, and Mg and Al were quantified by atomic absorption analysis, the mixture of WO ₃ and MoO ₃ was oxidized, respectively. 1350ppm by weight in material conversion
And 1400 ppm.

Example 6 A mixture of WO ₃ , MoO ₃ and MgO in the fifth layer (weight ratio: WO ₃ / MoO ₃ / MgO =
90/10 / 2.5), the weight ratio of MgO is fixed at 2.5, and the weight ratio of WO ₃ / MoO ₃ is 97 /
Except for changing to 3.95 / 5, 85/15, 80/20, 70/30, an electrochromic device was manufactured in the same manner as in Example 3, and after sealing with resin, the colored state was measured. , WO ₃ / MoO ₃ weight ratio is 95/5
In the range of 80 to 20/20, almost the same spectral characteristics as in Example 1 were obtained on the entire surface of the electrochromic device. When the weight ratio is 97/3, the ND slightly deteriorates,
In the case of / 30, the transmittance was reduced.

When the color erasing / decoloring speed was measured, WO
The decrease was within 5% as in Example 3, except that the sample of ₃ / MoO ₃ = 70/30 was reduced by 10%.

Comparative Example 1 A mixture of WO ₃ , MoO ₃ , MgO and Al ₂ O ₃ in the fifth layer (weight ratio: WO ₃ / MoO)
₃ / MgO / Al ₂ O ₃ = 90/10 / 2.5 / 1) except that the mixing ratio was changed to 90/10 / 0.5 / 0.5. After the chromic element was manufactured and sealed with a resin, the colored state was measured. As a result, the same spectral characteristics as in Example 1 were obtained.

However, when the color erasing / discharging speed was measured, it was 40% lower than that in the case where the fifth layer had WO ₃ = 100%.

The substrate on which only the fifth layer was formed was dissolved in nitric acid and hydrofluoric acid, and Mg and Al were quantified by atomic absorption spectrometry. However, the mixture of WO ₃ and MoO ₃ showed noise components. The equivalent weight ratio was less than 10 ppm.

Comparative Example 2 A mixture of WO ₃ , MoO ₃ , MgO and Al ₂ O ₃ in the fifth layer (weight ratio: WO ₃ / MoO)
₃ / MgO / Al ₂ O ₃ = 90/10 / 2.5 / 1), except that the mixing ratio was changed to 90/10/0/1, to manufacture an electrochromic device in the same manner as in Example 1. Then, after sealing with resin, the coloring state was measured, and the same spectral characteristics as in Example 1 were obtained.

However, when the color erasing / discharging speed was measured, it was 39% lower than that of the fifth layer having WO ₃ = 100%.

[0048]

Since the present invention is configured as described above, it has the following effects.

[0049] WO ₃ even when added to M ₀ O ₃ for ND reduction, it is possible to obtain an electrochromic layer and the same degree of wear decolorizing rate of only WO _3. By using such an electrochromic layer as an electrochromic layer having a reduced coloring property, a high-quality electrochromic element having excellent responsiveness can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a film configuration of an electrochromic device according to one embodiment.

FIG. 2 is a graph showing the spectral characteristics of the electrochromic device according to Example 1.

[Explanation of symbols]

10 transparent glass substrate 11, 16 a transparent conductive layer 12 oxidative coloring electrochromic layer 13 Ir (hydr) oxide and mixed layer 14 transparent ion conductive layer of SnO ₂ 15 reductive coloring electrochromic layer

(72) Inventor Junji Terada 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (5)

[Claims] 1. An electrochromic layer containing a mixture of WO ₃ and M ₀ O ₃ as a main component, wherein MgO is added as an additive for increasing the color erasing / discharging speed. layer. 2. An electrochromic layer containing a mixture of WO ₃ and M ₀ O ₃ as a main component, wherein ZrO ₂ , Y ₂ O ₃ and Al ₂ O are used as additives for increasing the color erasing / decoloring speed. _An electrochromic layer, wherein at least one of the _three and MgO are added. _3. The electrochromic layer according to claim 1, wherein the amount of the additive is in the range of 10 to 1000 ppm by weight with respect to the mixture of WO ₃ and M ₀ O _3. . 4. The weight ratio of WO ₃ to M ₀ O ₃ of the mixture is 9
The electrochromic layer according to any one of claims 1 to 3, wherein the ratio is in the range of 5: 5 to 80:20. 5. It has a plurality of thin films laminated on a substrate,
An electrochromic device, wherein one of the electrochromic layers is the electrochromic layer according to any one of claims 1 to 4.