JPH06289435A - Electrochromic element - Google Patents

Abstract

PURPOSE:To distribute the transmittance and reflectivity of coloration stepwise within the element plane by dividing one of electrode layers to plural electrodes by fine lines consisting of a part of an electrochromic layer. CONSTITUTION:The electrode layer B of the electrochromic device (ECD) consisting of the electrochromic (EC) layer C and a pair of the electrode layers A, B holding the layer is divided to the plural electrodes Bs by the fine grooves Mh consisting of a part of the EC layer. The electrodes Bs are electrically conducted to each other via the high-resistance EC layers in plural fields. Only the upper and lower EC layer parts of the first divided electrode are colored if a coloring voltage is impressed between the one electrode (first divided electrode) among these electrodes Bs and the electrode layer opposite thereto. The EC layer parts of the adjacent divided electrodes are successively colored via the fine grooves consisting of the high-resistance EC layers as time passes by, but a voltage drop arises the furtherer from the first divided electrode and the coloring density is decreased stepwise with the first divided electrode as a start point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrochromic device used for light quantity control and display.

[0002]

2. Description of the Related Art A phenomenon in which a reversible electrolytic oxidation or reduction reaction occurs when a voltage is applied to cause reversible color fading is called electrochromism. Using an electrochromic (hereinafter sometimes abbreviated as EC) substance exhibiting such a phenomenon, an EC element (hereinafter, referred to as EC
It may be abbreviated as D), and an attempt to use this ECD for a light quantity control element (for example, a light control glass or an antiglare mirror) or a numerical display element using 7 segments is 2
It has been done for more than 0 years.

For example, an ECD formed by sequentially laminating a transparent electrode layer (cathode), a tungsten trioxide thin film layer, an insulating layer such as silicon dioxide, and an electrode layer (anode) on a glass substrate.
(See Japanese Examined Patent Publication No. 52-46098) is known as an all-solid-state ECD. When a voltage (coloring voltage) is applied to this ECD, the tungsten trioxide (WO ₃ ) thin film layer is colored blue. Then, when a reverse voltage (decoloring voltage) is applied to this ECD, the blue color of the WO ₃ thin film layer disappears and the WO ₃ thin film layer becomes colorless. The mechanism of this color fading and discoloration has not been clarified in detail, but it is understood that a small amount of water contained in the WO ₃ thin film layer and the insulating layer (ion conductive layer) controls the color fading and coloration of WO _3. There is.

The reaction formula for coloring is estimated as follows. Another known ECD is a reduction coloring EC layer (for example, W) between a pair of electrode layers on an element substrate.
O ₃ ), an ion conductive layer, and a reversible electrolytic oxidation layer (for example, oxidization or iridium hydroxide) are laminated, so that a predetermined voltage can be applied between both electrode layers.

By the way, at least one of the pair of electrode layers that directly or indirectly sandwich the EC layer must be transparent in order to make the color of the EC layer visible to the outside. Especially in the case of a transmissive ECD, both electrode layers must be transparent. Currently, SnO is used as the transparent electrode layer material.
₂ , In ₂ O ₃ , ITO (mixture of In ₂ O ₃ and SnO ₂ ), ZnO, etc. are known, but these materials have relatively poor transparency and must be thin. For this reason, the ECD is usually formed on a substrate (for example, a glass plate or a plastic plate).

In order to apply a voltage from an external power supply, the pair of electrode layers is provided with a take-out electrode which is a connecting portion with external wiring. When a transparent electrode layer is used as the electrode layer, the transparent electrode layer has a higher resistance than external wiring,
A low-resistance take-out electrode is often provided on (that is, in contact with) the transparent electrode layer. Usually, a low-resistance electrode portion is provided in a strip shape (for example, a metal clip is attached) around the transparent electrode layer located at the end portion of the substrate surface to form a low-resistance extraction electrode.

The ECD is used by arranging a sealing substrate for protecting the element so as to face the element substrate and hermetically sealing it with, for example, an epoxy resin or the like depending on the application.

[0008]

In the conventional ECD, when a coloring voltage is applied between a pair of electrode layers, when the distance between the extraction electrodes of both electrode layers is small, the entire element surface immediately becomes a uniform coloring state and the extraction is performed. Even when the distance between the electrodes is large, the entire element surface is in a substantially uniform colored state in a relatively short time.

That is, in the conventional ECD, the transmittance and the reflectance of coloring are distributed stepwise in the device surface, and this state cannot be maintained for a long time. An object of the present invention is to provide an electrochromic device capable of gradually distributing the transmittance and the reflectance of coloring in the device surface and maintaining this state for a long time.

[0010]

Therefore, in the first aspect of the present invention, "in an electrochromic device comprising at least an electrochromic layer and a pair of electrode layers sandwiching the electrochromic layer, one of the electrode layers is the electrochromic layer. There is provided an electrochromic device (claim 1) characterized in that it is divided into a plurality of electrodes by a thin groove formed of a part.

A second aspect of the present invention is that "a drive circuit for applying a predetermined voltage is provided between an arbitrary electrode of the plurality of electrodes and an opposing electrode layer.
An electrochromic device according to claim 2 is provided.

[0012]

The thin groove interposed between the divided electrodes according to the present invention is formed by a part of the EC layer (reversible electrolytic oxidation layer or reduction coloring EC layer). The EC layer is not a perfect insulator, but a resistor of several mega Ω / □. That is, the plurality of electrodes are electrically connected via the high-resistance EC layer.

When a coloring voltage is applied from an external power source only between one of the divided electrodes (referred to as a first divided electrode) and the opposing electrode layer, the upper or lower side of the first divided electrode is applied. Only the portion of the EC layer located at is colored. Then, after a lapse of time, the EC layer portion of the adjacent divided electrode which is electrically connected to the first divided electrode through the narrow groove formed of the high-resistance EC layer is also colored. Similarly, with the passage of time, E of other divided electrodes that are not directly connected to the external power source
The C layer portion is also colored.

However, since each of the divided electrodes is only electrically connected through the high resistance EC layer, a voltage drop occurs as the distance from the first divided electrode directly connected to the external power source increases, resulting in each divided electrode. The coloring density of the EC layer portion of the electrode is reduced. Therefore, the coloring density can be gradually reduced starting from the EC layer portion of the first divided electrode. EC
Even if D is colored stepwise within the element surface, if the insulating layer (ion conductive layer) or the EC layer has high ionic conductivity (ion conductivity), the coloring concentration becomes uniform over the entire element surface over time. Becomes Therefore, in order to maintain the stepwise colored state for a long time, it is preferable to lower the ionic conductivity of the insulating layer (ion conductive layer) or the EC layer.

The EC element according to the present invention is arranged so as to face any of the plurality of divided electrodes so that the EC element according to the present invention can be colored stepwise at any position and range within the element surface of the ECD. It is preferable to provide a drive circuit for applying a predetermined voltage between the electrode layer and the electrode layer. For example, a driving circuit as shown in FIG. 2 is provided in the ECD, and a predetermined voltage is applied between an arbitrary divided electrode and an opposing electrode layer, so that a certain region in the device surface is uniformly colored. It is possible to make a stepwise colored state from that area (FIG. 3).
reference).

In order to maintain a stepwise colored state for an arbitrary time, the ECD according to the present invention applies a coloring voltage between an arbitrary divided electrode and a counter electrode layer among a plurality of divided electrodes. At the same time, a driving circuit capable of applying an erasing voltage between another divided electrode and the counter electrode layer (see, for example, FIG.
It is preferable to provide the driving circuit shown in FIG. Various patterns can be used for the divided electrodes. For example, a divided pattern of a geometrical pattern may be used, but in order to make stepwise coloring effective, the width of the thin groove interposed between the divided electrodes according to the present invention is 5 to 500 μm. In particular, the thickness is preferably 10 to 200 μm. The width of the divided electrodes is preferably 1 to 20 mm, particularly 2 to 5 mm.

The laminated structure of the ECD according to the present invention is not particularly limited, but the solid type ECD structure has four layers such as an electrode layer / EC layer / ion conductive layer / electrode layer. Structure, electrode layer / reduction coloring type EC layer /
A five-layer structure such as an ion conductive layer / reversible electrolytic oxidation layer / electrode layer can be mentioned. The reduction coloring type EC layer is generally composed of WO
₃ , MoO _3, etc. are used. For the ion conductive layer, for example, silicon oxide, tantalum oxide, titanium oxide, aluminum oxide, niobium oxide, zirconium oxide, hafnium oxide, lanthanum oxide, magnesium fluoride or the like is used.

The ionic conductive layer, which is an insulator for electrons, contains protons (H ⁺ ) and hydroxy ions (O ² ).
H ^-) becomes a good conductor for. A cation is required for the coloration / decoloration reaction of the EC layer, and H ⁺ and Li ⁺ must be contained in the EC layer and the like. H ⁺ does not have to be an ion from the beginning, and H ⁺ may be generated when a voltage is applied, and thus water may be contained instead of H ⁺ . This water is very small and sufficient, and even water that naturally infiltrates from the atmosphere often fades.

Either the EC layer or the ionic conductive layer may be on either side. Further, a reversible electrolytic oxidation layer or a catalyst layer may be arranged with an ion conductive layer sandwiched between the EC layer (which also serves as an oxidation coloring EC layer in some cases).
Examples of such a layer include iridium oxide or hydroxide, nickel, chromium, vanadium, ruthenium, rhodium and the like. These substances may be dispersed in the ion conductive layer or the transparent electrode layer, or conversely may be dispersed therein.

The ECD according to the present invention can be applied to, for example, spectacle lenses, architectural windows, displays such as neon signs, and the like. Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.

[0021]

Embodiment 1 FIG. 1 is a schematic vertical sectional view (a), (b) of an ECD according to this embodiment and a schematic plan view (c) of divided electrode layers. The ECD shown in FIG. 1 was produced by the following procedure. (1) An ITO electrode layer was formed on the entire surface of the glass element substrate S having a size of 15 cm × 8 cm by DC sputtering. The substrate heating temperature during sputtering is 200 °
C, the thickness of the ITO electrode layer was 2000Å, and the sheet resistance of the ITO electrode layer was 10Ω. (2) A groove (width 1 mm) M is formed in the ITO electrode layer by photo etching or laser cutting, and the upper part I
The extraction electrode F for the TO electrode layer A and the lower electrode layer B were separated. Further, the lower electrode layer B was divided by a groove (width 100 μm) Mh in a direction perpendicular to the groove M to form a plurality of divided electrodes Bs having a width of 3 mm. (3) By DC sputtering, a reversible electrolytic oxidation layer made of a mixture of iridium oxide and tin oxide is formed on the groove portions between the plurality of divided electrodes and the plurality of divided electrodes (thickness 3000).
Å), and the thin groove Mh ′ formed of a part of the reversible electrolytic oxidation layer C and the reversible electrolytic oxidation layer C on the divided electrode were formed. The ionic conductivity of the reversible electrolytic oxidation layer C was made lower by increasing the sputtering rate and the film thickness. (4) Reversible electrolytic oxidation layer C by DC sputtering
An ion conductive layer D of tantalum oxide and a tungsten oxide layer E (each film thickness of 4000 Å) were sequentially formed thereon. The ionic conductivity of the ionic conductive layer D and the tungsten oxide layer E was made low by increasing the sputtering rate and the film thickness. (5) The upper ITO electrode layer A was formed by DC sputtering. At this time, the ITO electrode layer A was formed so that one end thereof was in contact with the extraction electrode F already formed on the element substrate S. The substrate is not heated during sputtering, and the upper part I
The thickness of the TO electrode layer was 2000Å, and the sheet resistance of the electrode layer was 20Ω. (6) The element was sealed with the sheet R (modified EVA or plasticized PVB) of the epoxy resin or the interlayer film for laminated glass and the sealing substrate G made of glass. Then, the drive circuit K is connected to each extraction electrode Bs ′ of the plurality of divided electrodes Bs and the extraction electrode F of the upper electrode layer A, and an arbitrary divided electrode Bs is connected.
A predetermined voltage was applied between the upper electrode layer A and the upper electrode layer A (see FIG. 2) to fabricate the ECD of this example.

The divided electrode Bs1 (outer electrode Bs1 ') at the end of the ECD thus produced and the upper electrode layer A
When a coloring voltage of 2 V was applied from the driving power supply Su to the (take-out electrode F) for 30 seconds, gradual coloring was observed from one end to the other end of the ECD, and the gradual coloring state was maintained for 30 minutes or more. I was able to. Table 1 shows the transmittance (measured with a He-Ne laser) in this stepwise colored state. In addition, a schematic state diagram of stepwise coloring is shown in FIG.
It shows in (a).

[0023]

Example 2 The divided electrode Bs1 (extraction electrode Bs1 ′) at the end of the ECD manufactured in Example 1 and the adjacent divided electrode Bs2 (extraction electrode Bs2 ′) and the upper electrode layer A (extraction electrode F) are formed. When a coloring voltage of 2 V was applied for 30 seconds from the driving power supply Su in the meantime, the divided electrodes Bs1 and Bs
The EC layer region on No. 2 was in a substantially uniform colored state, and the region beyond that was in a stepwise colored state (see Table 1, FIG. 3b). Moreover, such a state could be maintained for 30 minutes or more.

[0024]

[Comparative Example] The lower electrode layer is not divided into a plurality of electrodes by the thin groove which is a part of the EC layer, and a metal clip is attached to each electrode lead-out portion F, B'of the upper and lower electrode layers. An ECD was produced in exactly the same manner as in Example 1 except that external wiring was bonded to and connected to the drive power source Su.

When a coloring voltage of 2 V was applied to this ECD from the driving power source Su for 30 seconds, the entire surface of the device was colored almost uniformly (see Table 1).

[0026]

[Table 1]

[0027]

As described above, according to the present invention, the transmittance and the reflectance of coloring can be gradually distributed in the ECD plane, and this state can be maintained for a long time.

[Brief description of drawings]

1A and 1B are schematic vertical sectional views (a) and (b) of an ECD according to Example 1, and a schematic plan view (c) of a divided electrode layer.

FIG. 2 is a schematic plan view of an EC device according to the present invention in which a drive circuit K for applying a predetermined voltage is provided between an arbitrary divided electrode Bs and an electrode layer A among a plurality of divided electrodes Bs. .

FIG. 3 is a state diagram schematically showing a stepwise coloring state of the ECD according to the present invention.

FIG. 4 is another example of the ECD according to the present invention, in which a coloring voltage is applied between an arbitrary divided electrode of a plurality of divided electrodes and a counter electrode layer, and at the same time, the divided electrode is opposed to another divided electrode. EC with a drive circuit that can apply decoloring voltage between the electrode layer
It is D.

[Explanation of symbols]

 A ... Upper electrode layer F ... Extraction electrode of upper electrode layer B ... Lower electrode layer B '... Derivation electrode of lower electrode layer Bs ... Split electrode Bs'. Split electrode extraction electrode E ... -Tungsten oxide layer D ... Ion conductive layer C ... Reversible electrolytic oxidation layer R ... Epoxy resin or interlayer film for laminated glass S ... Element substrate G ... Sealing substrate M ... Top Groove between electrode layer and lower electrode layer Mh ... Groove between divided electrodes K ... Driving circuit Su ... Driving power source

Claims (2)

[Claims] 1. An electrochromic device comprising at least an electrochromic layer and a pair of electrode layers sandwiching the electrochromic layer, wherein one of the electrode layers is divided into a plurality of electrodes by a narrow groove formed of a part of the electrochromic layer. An electrochromic device characterized in that 2. The electrochromic device according to claim 1, wherein a drive circuit for applying a predetermined voltage is provided between an arbitrary electrode of the plurality of electrodes and an electrode layer facing the arbitrary electrode.