JPH055536Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to improvements in electrochromic devices. Hereinafter, Electrochromic is referred to as "EC"
The EC element is abbreviated as "ECD".

[Conventional technology]

Electrochromism is a phenomenon in which electrolytic oxidation or reduction reactions occur reversibly when a voltage is applied, resulting in reversible coloring. Using an electrochromic (hereinafter abbreviated as EC) material that exhibits such a phenomenon, we create an EC element (hereinafter abbreviated as ECD) that can be colored and decolored by voltage manipulation, and then use this ECD as a light amount control element (for example, Attempts to use it for anti-glare mirrors) and numeric display elements using 7 segments have been made.
It's been going on for over 20 years. For example, an ECD (Japanese Patent Publication No. 52-46098 ) is known as an all-solid-state ECD. When voltage is applied to this ECD, the tungsten trioxide (WO ₃ ) thin film is colored blue.
Then, when we apply a reverse voltage to this ECD,
The blue color of the WO ₃ thin film disappears and becomes colorless. Although the mechanism of coloring and decoloring has not been 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 decolorization of WO ₃ . ing. The coloring reaction formula is estimated as follows.

Cathode side: H ₂ O→H ⁺ +OH ^- WO ₃ +nH ⁺ +ne ^- →H _o WO 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 that directly or indirectly sandwich the EC layer must be transparent in order to show the coloring and fading of the EC layer to the outside. Especially in the case of a transmissive ECD, both must be transparent. Currently known transparent electrode materials include SnO ₂ , In ₂ O ₃ , ITO (a mixture of SnO ₂ and In ₂ O ₃ ), and ZnO, but these materials have relatively poor transparency. For this and other reasons, ECDs are typically formed on a substrate, such as a glass plate or a plastic plate, and an example of the structure of such an ECD is shown in FIG.

In FIG. 4, A is the upper electrode Al, B is the lower transparent electrode, E is the reduction coloring EC layer (for example, WO ₃ ),
D represents an ion conductive layer, and C represents a reversible electrolytic oxidation layer or an oxidative coloring EC layer (e.g. iridium oxide or hydroxide), and basically an ECD is composed of only the laminated structure of A to B. , these ECDs are formed on the substrate S, as described above.

R is an ECD sealing material such as epoxy resin;
G is a protective sealing substrate.

In order to supply external power to electrodes A and B of such an ECD, a lead-out part is required for each, and at least a part of the lead-out part is exposed without being sealed by the sealing substrate. External wiring L _A and L _B were connected to this exposed lead-out portion by, for example, soldering.

Conventionally, the extraction part was formed using the same material and manufacturing method as the upper and lower electrodes, and therefore (a) ITO and other oxide thin films formed by vacuum thin film forming techniques such as vacuum evaporation, ion plating, and sputtering. Or (b) Al or other metal thin film was used.

However, in both cases (a) and (b), the extraction part is very thin, so there is a problem that the soldering work efficiency is low, and in the case of (a), the electrical resistance is relatively low. If you solder the external wiring directly, the low-resistance external wiring and the high-resistance lead-out part are in contact at one point, so the supply speed of charge from the external wiring to the entire electrode through the lead-out part is slow. However, there were problems such as poor responsiveness and uneven coloring and decoloring, and furthermore, when subjected to a hot water immersion test, the external wiring peeled off from the lead-out part. In the case of (b), there was a problem in that the take-out portion peeled off from the substrate when subjected to a hot water immersion test.

Some of the inventors of this invention first conducted research to solve these problems, and in 1988 they invented a method of attaching a low-resistance conductive clip to the extraction part and connecting external wiring to this. A patent application was filed on May 20th. This application has not been published yet and is hereinafter referred to as the prior application.

When a clip is used, it does not peel off even when subjected to a hot water immersion test, and the supply speed of charge from the external wiring to the entire high-resistance electrode through the lead-out part is fast, resulting in good response and no uneven coloring or decoloring. ECD that does not occur can be obtained.

[Problem that the invention attempts to solve]

However, even in the case of the ECD of the prior invention,
Metal electrodes, especially aluminum electrodes, used as low-resistance electrodes (sometimes also used as reflective layers) are relatively susceptible to corrosion, partly because they are very thin, and therefore have a short lifespan and low reliability. There was a problem.

[Means for solving problems]

As a result of intensive research into the problem of corrosion of metal electrodes, the inventors of the present invention found that even if they are simply sealed with a sealing material such as epoxy resin, the sealing layer is thin, so corrosive gases such as air and moisture can penetrate the sealing layer. They discovered that metal electrodes easily penetrate through the metal electrodes and cause corrosion, and in order to prevent this penetration, they conceived and experimented with sealing the metal electrodes using a sealing substrate and the above-mentioned clips. However, it still wasn't enough.

We researched the cause of this problem and found that even if the metal electrode is sandwiched between the substrate and the sealing substrate or clips, the end surface of the metal electrode remains exposed to the air, or at best the sealing material is thin. It was discovered that corrosive gases such as air and moisture can easily penetrate because the metal electrodes are only covered with By doing so, the metal electrode is formed inside the sealing area formed by the sealing substrate and the clip, thereby keeping the metal electrode sufficiently away from the end face, thereby making the penetration route from the end face sufficiently long, and preventing corrosion. The idea was to make it difficult for gas to enter, and this idea was developed.

Therefore, the present invention provides ``at least three layers of a lower electrode, an electrochromic layer, and an upper electrode on a substrate.
After laminating the layers in order, the top surface of each electrode except for at least a part of the lead-out part is sealed with a sealing substrate, and a conductive clip is attached to each of the unsealed and exposed lead-out parts, and the lead-out part is connected to the outside through this. In an electrochromic device formed by connecting wiring, those or parts of the upper electrode, the lower electrode, and their lead-out portions formed of metal are separated from the sealing region formed by the sealing substrate and the clip. The present invention provides an "electrochromic device" which is characterized in that it is made on the inside.

[Effect]

FIG. 5 is a perspective view showing an example of the conductive clip used in the present invention;
As shown in the figure, it is approximately gutter-shaped with a substantially U-shaped cross section.

This clip is connected to the piece H ₁ in contact with the extraction part.
, a piece _H2 that holds the board, and a connecting plate part _H3 that connects the two. and fragment H ₁ and fragment H ₂
Then, the peripheral portion of the substrate having the extraction portion formed on the surface of the peripheral portion is sandwiched. Therefore, after being sandwiched, it is preferable that the pieces _H1 and _H2 firmly grip the substrate so that the clips do not come off the substrate. Therefore, as shown in Fig. 6, the clip has a shape in which the area between the fragment _H1 and the fragment _H2 is narrow near the entrance and widens as it approaches the connecting plate portion _H3 , and is made of a metal having spring properties. Preferably. Metal is preferred because it can be soldered well. Metals with preferable spring properties include:
One example is phosphor bronze, but other materials such as steel are also used. The metal clip is made of a relatively soft metal, such as tin, at least on the contact surface with the extraction part.
It may be coated with indium, solder, mixtures thereof, or other conductive materials. Such a clip would have the best contact with the outlet.
This is because metal surfaces generally have subtle irregularities when viewed under a microscope, and mere pressure contact does not provide the best possible contact with the extraction portion. Also, tin plating on phosphor bronze clips has the advantage of improving corrosion resistance.

The length l of the clip should be sufficiently longer than the metal extraction part. Although the overall shape of the clip was described above as approximately gutter-like, it may be curved in the length direction to match the shape of the ECD. For example, even if the ECD has a rectangular board, the board may have an R along the circumferential surface of a cylinder, or if the board is not a rectangle but a circle cut off with two parallel straight lines. If the clip has a shape as shown in FIG. 7 or a television screen as shown in FIG. 8, the clip may have a shape that matches the shape of the periphery of such a substrate.

If the ECD is an all-solid thin film type, the thickness of the ECD itself excluding the substrate is very thin (for example, 0.01 mm or less), whereas the clip is generally thick, 0.05 to 2 mm, due to the material. ,ECD
When attached to the ECD, as shown in Figure 9,
Compared to , the clip fragment H ₁ is thicker and therefore
A step appears between the ECD display section and fragment _H1 .
Therefore, if the sealing substrate is positioned using this step, the positioning work can be performed easily and accurately.

In order to make this positioning work easier and more accurate, the tip of the clip segment _H1 may be erected vertically to provide an abutting piece _H4 , as shown in FIG.
If the clip is curved in the length direction, it is easier to curve the clip by making wedge-shaped slits (splits) here and there in advance in the abutment piece _H4 . Also,
The abutting piece _H4 does not need to be erected on the entire edge of the tip of the fragment _H1 , but may be partially erected.

As shown in FIG. 9, in the present invention, the left and right ends of the sealing substrate are in contact with the clip, and there is no gap between them. If a gap exists, even if the extraction part is sealed with a sealing material such as epoxy resin, the extraction part will be corroded by the influence of corrosive gases such as air and moisture that penetrate through the sealing material. .
However, if the metal electrode including the lead-out part is sealed with the sealing substrate and the clip, the lead-out part is less likely to be corroded. Therefore, even if the electrode is made of a metal that is easily corroded, such as Al, there is no need to change only the extraction part or the surrounding area to ITO or other oxide-based material that is resistant to corrosion.
The manufacturing cost of ECD will decrease.

The conductive clip used in the present invention may also serve as a shielding or decorative material for the periphery of the electrochromic device. Especially in the case of an anti-glare mirror (the amount of reflected light is electrically controlled) where the ECD is viewed from the board side, it is aesthetically preferable to make the display area as large as possible and the peripheral area thin. , it is advantageous to use both.

The clip can be attached to the ECD before or after sealing, but it should be attached before or after sealing, and the sealing material is applied to the sealing substrate and then attached to the ECD.
When the encapsulant is cured on top of that, the encapsulant enters through the invisible minute gap between the take-out part and the piece _H1 and fills the relatively large gap between the edge of the substrate and the clip. (See Figure 11). In this case, compared to when the clip is attached after sealing and the sealant does not fill the gap, the sealant makes it difficult for external moisture to enter the extraction part.
The extraction part is less likely to be corroded. Furthermore, since the sealing material that has entered the gap adheres the substrate and the clip, there is an advantage that the clip is difficult to separate from the substrate.

If the clip is made of solderable material, when connecting external wiring to the clip,
Soldering is sufficient, but if the clip is made of metal, the connection may be made by crimping or clamping instead of soldering.

When using metal clips, crimping or clamping methods include (1) simply sandwiching the exposed external wiring between the end of the clip (particularly fragment H ₃ ) and the board, and variations thereof; For example, a hole, a groove, or a slit is made in the middle of the clip in the length direction, and the exposed end of the external wiring is inserted through this hole or groove to create a gap between the clip (particularly fragment H ₃ ) and the board. As a modification of the pinching method, two holes, grooves, or slits (splits) are made in the middle of the clip in the length direction, and the exposed tip of the external wiring is inserted through the first hole, groove, or slit (splits). (2) using a longer clip, inserting it through the second hole, groove or slit, and sandwiching the exposed external wiring between the clip (particularly the fragment H ₃ ) and the board;
A method of inserting the tip of the exposed external wiring into the clip protruding from the ECD and then crushing the clip. An example of this method is to provide a "J"-shaped crimp piece _H5 and crimp the exposed tip of the external wiring L _A between these pieces. Note that the crimp piece _H5 may be created by bending a part of the piece _H1 .

When connecting the external wiring to the clip, if the connection is made by soldering, it is preferable to connect it before attaching it to the ECD. This way the ECD will not be exposed to the heat of soldering and there will be no risk of heat damage.

Since the connection between the external wiring and the clip is physically and chemically weak, it is preferable to seal it. It is particularly preferable to perform this sealing simultaneously with the sealing of the ECD, since this eliminates the need for a separate sealing step.

On the other hand, although the laminated structure of the ECD in the present invention is not particularly limited, it is a solid type.
The structure of ECD is, for example, electrode layer/EC layer/
Examples include a four-layer structure such as an ion conductive layer/electrode layer, and a five-layer structure such as an electrode layer/reduction colored EC layer/ion conductive layer/reversible electrolytic oxidation layer or oxidation colored EC layer/electrode layer.

Examples of materials for the transparent electrode include SnO ₂ , In ₂
O ₃ , ITO, etc. are used. Such electrode layers are generally formed by vacuum evaporation, ion plating,
It is formed using vacuum thin film forming techniques such as sputtering. (Reduction colorability) The EC layer is generally WO ₃ ,
MoO ₃ etc. are used.

Examples of the ion conductive layer include silicon oxide, tantalum oxide, titanium oxide, aluminum oxide, niobium oxide, zirconium oxide, hafnium oxide,
Lanthanum oxide, magnesium fluoride, etc. are used. Although thin films of these materials are insulators for electrons due to the manufacturing method, they are good conductors for protons (H ⁺ ) and hydroxy ions (OH ⁻ ). Cations are required for the coloring and decoloring reaction of the EC layer, and it is necessary to contain H ⁺ ions and Li ⁺ ions in the EC layer and other parts. H ⁺ ions do not need to be ions to begin with, and when a voltage is applied,
It is sufficient that H ⁺ ions are generated, and therefore water may be contained instead of H ⁺ ions. Very little of this water is sufficient, and often even moisture that naturally enters from the atmosphere will discolor.

The EC layer and the ion conductive layer may be placed either on top or on the bottom. Furthermore, a reversible electrolytic oxidation layer (or oxidation-colored EC layer) or a catalyst layer may be provided to the EC layer with an ion conductive layer interposed therebetween.
Such layers include, for example, 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, or may be dispersed therein. The opaque electrode layer may also serve as a reflective layer, for example, gold,
Metals such as silver, aluminum, chromium, tin, zinc, nickel, ruthenium, rhodium, and stainless steel are used.

Hereinafter, the present invention will be explained in detail with reference to Examples with reference to FIGS.

〔Example〕

An ITO electrode layer is formed on the entire surface of a rectangular glass substrate S, and then patterned by photo-etching to form a preliminary lead-out part _Fp for the upper electrode A, a lower electrode B separated from it, and a series of lower electrodes B. A subsequent take-out portion _B1 was formed (see Figures 2 and 3). still,
In some cases, the preliminary extraction portion F _p may be omitted, and these patterns may be directly formed by mask vapor deposition of ITO.

Next, a reversible electrolytic oxidation layer C made of a mixture of iridium oxide and tin oxide, a tantalum oxide layer D, and a tungsten oxide layer E were formed in this order.

Thereafter, Al was vapor-deposited using a mask as the upper electrode A and the lead-out part F, and at this time, Al was formed so as to cover almost the entire preliminary lead-out part F _p already formed on the substrate S. The portion of the mask-deposited Al pattern that rests on the preliminary extraction portion F _p constitutes the extraction portion F of the upper electrode.

The Al electrode must be formed inside the outline of the substrate S, and inside the sealing area (indicated by a dashed line) formed by the sealing substrate and the clip, as shown in FIG. No. This allows a sufficiently long path for corrosive gas to enter the Al electrode from the end surfaces (substrate end surface, sealing substrate end surface, and clip end surface), thereby preventing corrosion of the Al electrode.

Next, attach two conductive clips H made of phosphor bronze in advance.
This was prepared and the external wiring L _A or L _B was connected to it by soldering or conductive adhesive.

The clips H are attached to the short sides of the board, so that the clip fragments _H1 can be attached to the extraction parts F,
B ₁ was crimped.

Finally, the sealing glass plate G coated with a large amount of epoxy resin sealant R was placed on top of the ECD, and the sealing substrate G was placed between the two opposing clips. Since the distance between the two clips H and the length of the glass plate G are almost the same, the positioning of the glass plate G can be done by placing the glass plate G between the clips.
It was easy and quick. Clip H, sealing substrate G, Al upper electrode A, and Al extraction part F in this state
Fig. 14 shows the position of . As a result, the Al electrode is sealed with the sealing substrate and the clip, and the Al electrode is sealed with the sealing substrate and the clip.
It will be further appreciated that the electrode end face is sufficiently separated from the sealing substrate end face and the clip end face.

When the sealing material R was left to harden, the excess sealing material R covered the take-out portion, a part of the clip, and the external wiring connection portion, and filled the gap between the substrate S and the clip, thereby sealing them. This made the clip firmly adhered to the substrate and could not be removed.

In this way, the ECD of this example was produced. this
A vertical section of the ECD is shown in Figure 1. This figure is partially deformed and does not have accurate dimensional ratios.

Coloring voltage (+) is applied to this ECD from the drive power supply Su.
When a voltage of 1.35V) is applied, the reflectance decreases to 15% (after 10 seconds) for light L with a wavelength of 633 nm incident from the substrate S side, and this reflectance is maintained for a while even after the voltage application is stopped. Ta. When a decoloring voltage (-1.35V) was applied this time, the reflectance recovered to 65% (10
seconds later).

Therefore, the ECD of this embodiment is useful as an anti-glare mirror for automobiles and other vehicles.When the strong light of a car approaching from behind hits the mirror, applying a voltage to reduce the reflectance will prevent the driver from being dazzled. It disappears.

In this embodiment, the upper electrode and the lower electrode each have one extraction portion on the short side of the substrate, but an extraction portion may also be provided at the terminal portion and charges may be supplied from both. In this case, the lead-out parts of one electrode are provided on both short sides of the substrate, the lead-out parts of the other electrode are provided on both short sides of the board, and the lead-out parts of the other electrode are provided on both long sides of the board. The clips will be provided on all four sides of the board.

In addition, in this example, the ITO extraction part _B1 was also sealed by attaching a clip H in the same way as the Al extraction part F, but since ITO is resistant to corrosion, in extreme cases it may be exposed from the clip H. Good too.
In any case, it is sufficient that the end surface of the metal electrode, which is susceptible to corrosion, is sufficiently separated from each end surface of the substrate, the sealing substrate, and the clip.

[Effect of idea]

As described above, according to the present invention, when a conductive clip is attached in advance to the electrode extraction part of the ECD and external wiring is connected through this, the sealing substrate and the clip form a seal that protects the metal electrode that is easily corroded. This seals the end face of the metal electrode at a sufficient distance from the end face of the substrate, the end face of the sealing substrate, and the end face of the clip, thereby preventing corrosive gas entering from the end face from reaching the metal electrode. I made it difficult,
Longer life and increased reliability.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical sectional view of an ECD according to an embodiment of the present invention. FIG. 2 is a schematic plan view of the substrate S on which the ITO electrode pattern according to the embodiment is formed. FIG. 3 is a sectional view taken along the arrow in FIG. 2. FIG. 4 is a schematic vertical cross-sectional view of a conventional ECD. FIG. 5 is a perspective view showing an example of a conductive clip. FIG. 6 is a cross-sectional view of the conductive clip of FIG. 5. FIG. 7 is a plan view showing an example of the substrate. FIG. 8 is a plan view showing an example of the substrate. FIG. 9 is a schematic cross-sectional view showing an example of the ECD of the present invention, expressed in a dimension ratio closer to the actual size than that in FIG. 1. FIG. 10 is a sectional view of another example of a conductive clip. FIG. 11 is an explanatory diagram showing how the sealing material has entered the gap between the substrate and the conductive clip. FIG. 12 is a cross-sectional view of yet another example of a conductive clip. FIG. 13 is a schematic plan view showing a state in which Al was finally mask-deposited as the upper electrode A and its extraction portion F in an embodiment of the present invention. The imaginary line (two-dot chain line) represents the sealing substrate G, and clips H are prepared on both sides of the substrate.
FIG. 14 is an explanatory diagram showing the positional relationship between the Al electrode pattern Al, the clip H, and the sealing substrate G in the ECD of the example. Explanation of symbols of main parts, S...substrate, A...upper electrode, B...lower electrode, _B1 ...lower electrode extraction part, E...reduction coloring EC layer or WO ₃ layer, F
... Upper electrode extraction part, F _p ... Upper electrode preliminary extraction part, H ... Conductive clip, G ... Sealing substrate (glass plate), R ... Sealing material, L _A , L _B ... ...External wiring, Al...Aluminum electrode (a type of metal electrode), K...Sealing area.

Claims (1)

[Claims for Utility Model Registration] 1. After at least three layers of a lower electrode, an electrochromic layer, and an upper electrode are sequentially laminated on a substrate, the upper surface is covered with a sealing substrate except for at least a part of the lead-out portion of each electrode. In an electrochromic device formed by sealing and attaching conductive clips to the unsealed and exposed extraction parts, and connecting external wiring through these, the upper electrode and the lower electrode and their extraction parts Items or parts made of metal,
An electrochromic device, characterized in that it is located inside a sealing region formed by the sealing substrate and the clip. 2. The electrochromic device according to claim 1, wherein the conductive clip is made of a substantially gutter-shaped metal having a substantially U-shaped cross section. 3. The electrochromic device according to claim 1, wherein the metal is made of aluminum.