JP4799113B2 - Electrochromic device and driving method thereof - Google Patents

Description

  The present invention relates to an improvement in an all-solid-state electrochromic (hereinafter referred to as “EC”) element, which prevents coloring due to a photochromic phenomenon. The present invention also relates to an improved driving method of the EC element.

  An EC element has been put into practical use as an antiglare mirror for vehicles, an antiglare meter panel for vehicles, a light control window glass for vehicles or for buildings, and the practical application is being studied. Here, the vehicular anti-glare meter panel is arranged in front of a vehicular meter having a metallic dial, and the meter dial is adjusted by adjusting the light transmittance according to the intensity of sunlight. The reflected light from the light is reduced to suppress glare.

  As a conventional EC element, for example, there is one described in Patent Document 1 below. The configuration is shown in FIG. On the transparent substrate 22, a first transparent conductive film 24, a solid electrolyte film (insulating intermediate layer) 34, an EC film (electrochromic layer) 26, and a second transparent conductive film 28 are sequentially stacked and formed as a whole. A transmissive EC element 32 is configured. A driving voltage is applied by the battery 30 between the first transparent conductive film 24 and the second transparent conductive film 28. The polarity of this drive voltage is switched by a switch 36. When the switch 36 is turned on to the C position side, the EC element 32 is colored. Once the EC element 32 is colored, even if the switch 36 is opened and the battery 30 is disconnected from the EC element 32 due to the so-called memory property, the colored state of the EC element 32 is maintained. On the other hand, when the switch 36 is turned on to the B position side, the EC element 32 is decolored. The erasing drive voltage value is adjusted by a potentiometer 37. Once the EC element 32 is decolored, the decolored state of the EC element 32 is maintained even if the switch 36 is opened due to memory characteristics and the battery 30 is disconnected from the EC element 32.

Japanese Examined Patent Publication No. 52-46098 (FIG. 2)

  The EC element 32 in FIG. 2 is characterized by having a memory property as described above. FIG. 3A shows an equivalent circuit of the EC element 32 of FIG. The first transparent conductive film 24 is expressed as electronic resistance (electric resistance acting on electronic conduction) Ra. The solid electrolyte membrane 34 is expressed as a parallel combination of ionic resistance (electric resistance acting on ionic conduction) RH and capacitance Ch due to ionic conductivity. The EC film 26 is expressed as a parallel combination of a series connection of an ion resistance ΘW and a diffusion resistance ZW due to ion conductivity and a capacitance Cw. The second transparent conductive film 28 is represented as an electronic resistance Rb. The diffusion resistance ZW of the EC film 26 indicates that the process in the EC film 26 is a rate-limiting reaction.

  The equivalent circuit in FIG. 3A can be replaced with the equivalent circuit in FIG. The capacity C in FIG. 3B corresponds to the capacity Ch and the capacity Cw in FIG. The resistor RW and the capacitor CW in FIG. 3B correspond to the diffusion resistor ZW in FIG. FIG. 3B shows that the EC element 32 has a memory property due to the capacitance C.

Here, the EC film 26 is made of, for example, WO ₃ (tungsten oxide). However, since WO ₃ has photochromic properties, the WO ₃ film 26 is exposed to ultraviolet rays when irradiated with sunlight in applications used outdoors. Natural potential is generated in the interior of the glass, resulting in coloration. In other words, when receiving sunlight,
hν (light energy) → H ⁺ (hole) + e ⁻ (electron)
Reaction occurs, and H ⁺ and + e ⁻ are generated. further,
WO ₃ (colorless) + xH ⁺ + xe ⁻ → HxWO ₃ (colored)
The reaction becomes colored. Then, once the EC film 26 is colored, the color gradually becomes light, but because of the memory property, it does not disappear completely unless a decoloring current is applied. Therefore, when the conventional EC element 32 is used outdoors, the natural potential is released by connecting an external resistance between the electrode films 24 and 28 of the EC element 32 in order to prevent coloring due to ultraviolet rays. There is a need.

Further, when the conventional EC element 32 is repeatedly faded, O ₂ (oxygen) gas or H ₂ (hydrogen) gas is generated from the solid electrolyte film 34, and at the interface between the solid electrolyte film 34 and the EC film 26. Delaminating may occur. In particular, the conventional EC element 32 has low adhesion between the solid electrolyte membrane 34 and the EC membrane 26, and thus this film peeling is likely to occur.

  The present invention has been made in view of the above-described points, and an EC element that prevents coloring due to a photochromic phenomenon without using an external resistor and hardly causes film peeling at the interface between the solid electrolyte film and the EC film. Is also intended to provide.

The EC element of the present invention comprises a first transparent conductive film, a porous, electron leakage property (electron leakage property and minute electron conductivity) on a transparent substrate, electron leakage A transparent EC substrate and a second transparent conductive film are sequentially laminated, and a transparent sealing substrate is laminated on the second transparent conductive film via a transparent sealing material to form a transmission type. It is. Further, the EC element of the present invention is formed by sequentially laminating a reflective film and electrode film, a porous and electron leaking solid electrolyte film, an electron leaking EC film, and a transparent conductive film on a substrate, A transparent sealing substrate is bonded on a transparent conductive film via a transparent sealing material, and the reflective sealing substrate is configured to have a reflective type with the transparent sealing substrate side as the surface side. Further, the EC element of the present invention is formed by sequentially laminating a transparent conductive film, a porous, electron leaking solid electrolyte film, an electron leaking EC film, and a reflective film / electrode film on a transparent substrate, bonding a sealing substrate through the sealing material on the reflective film and the electrode film, the magnetic BenQ plate side is made to constitute a reflection type and surface.

According to the EC element of the present invention, since the solid electrolyte membrane and the EC film have electron leakage properties, the EC device as a whole has electron leakage properties. Therefore, e ⁻ generated in the EC film when the EC element is irradiated with sunlight is discharged by the electron leakage property, so that coloring of the EC film is prevented. Leakage current value of the EC element, the surface product 100 cm ² per be a decoloring voltage 1V at 0.1～0.2MA.

Further, according to the present invention, since the solid electrolyte film was porous, the interstices of the porous and H _{2 O} is taken from the air, of H _{2 O} in comparison with non-porous solid electrolyte membrane It becomes a solid electrolyte membrane containing much. As a result, O ₂ gas or H ₂ gas generated from the solid electrolyte membrane due to decoloration of the EC element is taken into H ₂ O contained in the porous solid electrolyte membrane, and therefore the solid electrolyte membrane and the EC membrane Accumulation at the interface is difficult, and film peeling at the interface between the solid electrolyte membrane and the EC membrane does not easily occur. In addition, by making the solid electrolyte membrane porous, the adhesion with the EC membrane formed on the solid electrolyte membrane is enhanced by the anchor effect due to the porous holes, and the film peeling at the interface between the solid electrolyte membrane and the EC membrane is performed. Is less likely to occur. Furthermore, by making the solid electrolyte membrane porous, the interface contact area with the EC membrane formed thereon is increased, resulting in increased ionic conductivity, easier ionic current flow, and higher coloring efficiency. (Coloring becomes darker. Coloring speed becomes faster.)

In the EC element of the present invention, the porous, electron-leakable solid electrolyte membrane is, for example, TaOx (x is 2.10 to 2.45, preferably 2.30 to 2.45, that is, a lower oxide of tantalum oxide. ) It can be composed of a membrane. In this case, the thickness of the TaOx film can be set to, for example, 500 to 900 nm, preferably 700 to 900 nm. A porous, electron-leakable TaOx (x is 2.10 to 2.45, preferably 2.30 to 2.45) film uses, for example, Ta ₂ O ₅ as a starting material, and Ta ₂ O ₅ It can be formed by a plasma vapor deposition method in which the O ₂ gas partial pressure is set lower than when the film is formed and the Ar gas partial pressure is set higher.

In the EC element of the present invention, the electron leaking EC film can be composed of, for example, a WO ₃ film. In this case, the film thickness of the WO ₃ film can be set to, for example, 300 to 700 nm, preferably 500 to 700 nm.

In the EC element of the present invention, the sealing material can be a hygroscopic sealing material (for example, epoxy resin, PVA (polyvinyl alcohol), PVB (polyvinyl butyral)). By using a hygroscopic sealing material, the sealing material can internally hold H ₂ O, H ⁺ and OH ⁻ . As a result, a part of the O ₂ gas or H ₂ gas generated from the solid electrolyte film due to the discoloration of the EC element is transmitted through the EC film and the transparent conductive film or the reflective film / electrode film, and H ₂ O, H ^{Since +} and OH ⁻ are incorporated in H ₂ O in the hygroscopic transparent encapsulant that internally holds, it is less likely to accumulate at the interface between the solid electrolyte membrane and the EC membrane, and at the interface between the solid electrolyte membrane and the EC membrane. Film peeling is less likely to occur. In this case, the film thickness of the hygroscopic sealing material may be, for example, 50 μm or more, preferably 50 to 500 μm.

  In the EC element driving method of the present invention, when a coloring command is issued, the driving voltage is continuously applied in the coloring direction for a predetermined time, and then the driving voltage is stopped and then driven in the coloring direction. The intermittent driving operation of one cycle is repeated at a cycle shorter than the predetermined time, and when a decoloring command is issued thereafter, the driving voltage is continuously applied in the decoloring direction for a predetermined time, and then the driving voltage is applied. Is to stop. According to this driving method, intermittent driving in the coloring direction is repeated at a short period during coloring, so that the colored state can be maintained even though the EC element is electron leaking. In addition, since the intermittent drive cycle is short, the variation range of the transmittance is small, and it is not necessary for the human eye to feel the variation of the transmittance.

(Embodiment 1)
Embodiment 1 of an EC element according to the present invention is shown in FIG. In this EC element 40, a first transparent conductive film 44, a solid electrolyte film 46, an EC film 48, and a second transparent conductive film 50 are sequentially laminated on a transparent substrate 42. A transparent sealing substrate 54 is bonded to the top via a hygroscopic transparent sealing material 52 to constitute a transmissive EC element as a whole. Clip electrodes 56 and 58 are mounted on two opposite sides of the EC element 40. The clip electrode 56 is electrically connected to the first transparent conductive film 44, and the clip electrode 58 is electrically connected to the second transparent conductive film 50. A lead wire 60 is connected to the clip electrode 56 with a bonding material 61 such as solder or conductive adhesive, and a lead wire 62 is connected to the clip electrode 58 with a bonding material 63 such as solder or conductive adhesive. The EC element 40 can be configured as, for example, a vehicle antiglare meter panel, a vehicle or architectural light control glass window, or the like.

In the first embodiment, the transparent substrate 42 and the transparent sealing substrate 54 are made of a transparent glass plate. The first transparent conductive film 44 and the second transparent conductive film 50 are made of ITO (indium tin oxide). The solid electrolyte film 46 is composed of a porous TaOx (tantalum oxide, x is 2.10 to 2.45, preferably 2.30 to 2.45) film having electron leakage. The EC film 48 is composed of a WO ₃ film having electron leakage. The hygroscopic transparent sealing material 52 is made of an epoxy resin.

FIG. 4A shows an equivalent circuit of the EC element 40 of FIG. The first transparent conductive film 44 is expressed as an electronic resistance Ra1. The TaOx film 46 is expressed as a parallel combination of an ion resistance RH1 due to ion conductivity and an electron resistance Rh1 due to electron leakage. The WO ₃ film 48 is expressed as a parallel combination of an ion resistance ΘW1 due to ion conductivity and a diffusion resistance ZW1 coupled in series with an electron resistance Rw1 due to electron leakage. The second transparent conductive film 50 is represented as an electronic resistance Rb1. Diffusion resistance ZW1 of WO ₃ film 48, shows that the process in the WO ₃ film 48 is the rate-limiting reaction.

The equivalent circuit of FIG. 4A can be replaced with the equivalent circuit of FIG. 4B because the electron leakage of the TaOx film 46 and the WO ₃ film 48 is small (the electronic resistances Rh1 and Rw1 are large). The resistor R1 in FIG. 4B corresponds to the capacitive resistor Rh1 and the resistor Rw1 in FIG. The resistor RW1 and the capacitor CW1 in FIG. 4B correspond to the diffused resistor ZW1 in FIG. According to FIG. 4B, the EC element 40 has an electron leakage property due to the electronic resistance R1, and even if a natural potential is generated (or is about to be generated) inside the WO ₃ film 48 due to ultraviolet rays, the electronic resistance Since it is discharged immediately at R1, it is prevented from being colored by the photochromic phenomenon. Therefore, no external resistance for releasing the natural potential is required.

If the leakage current value between the TaOx film 46 and the WO ₃ film 48 of the EC element 40 is too large, the memory performance is greatly deteriorated, coloring becomes insufficient and power consumption increases. Therefore, 0.1 to 0.2 mA is preferable at an erasing voltage of 1 V per 100 cm ² .

  An example of a drive circuit for the EC element 40 of FIG. 1 is shown in FIG. Clip electrodes 56 and 58 of the EC element 40 are connected to a DC power supply 66 via lead wires 60 and 62 and a switch 64. The polarity of the DC power supply 66 is switched by the switch 64. That is, if the switch 64 is connected to the contact a, the clip electrode 56 side becomes + polarity and the clip electrode 58 side becomes -polarity, and a voltage in the coloring direction is applied to the EC element 40. When the switch 64 is connected to the contact c, the clip electrode 56 side becomes -polarity and the clip electrode 58 side becomes + polarity, and a voltage in the coloring direction is applied to the EC element 40. Further, when the switch 64 is connected to the contact b, the circuit is opened, and the applied voltage between the clip electrodes 56 and 58 becomes zero. The control circuit 68 switches the switch 64 based on a coloring command or a decoloring command issued by manual operation of the operation switch or the like.

An example of the manufacturing process of the EC element 40 of FIG. 1 will be described.
(Step 1) On the surface of the transparent substrate 42 composed of a transparent glass plate having a size of 100 mm × 100 mm, an ITO film is set as the first transparent conductive film 44 by an ion plating method, and the substrate temperature is set to 250 ° C. Then, a film is formed to a thickness of 200 nm. The sheet resistance of the deposited ITO film 44 is 10Ω / □. The first transparent conductive film 44 can be composed of an In ₂ O ₃ film, a SnO ₂ film, or the like instead of the ITO film. Further, as a method for forming the first transparent conductive film 44, an evaporation method, a sputtering method, or the like can be employed instead of the ion plating method.

  (Step 2) The edge of the formed first transparent conductive film 44 on the side where the clip electrode 58 is mounted is removed over a predetermined width d by a photoetching method, a laser scribing method, or the like, and the transparent substrate 42 is removed at the edge. To expose. This is to prevent the first transparent conductive film 44 and the clip electrode 58 from contacting when the clip electrode 58 is attached. Instead of the photoetching method and the laser scribing method, the first transparent conductive film 44 is formed by covering the edge on the side where the clip electrode 58 is mounted with a mask over a predetermined width d. The first transparent conductive film 44 can be prevented from being formed on the edge.

(Step 3) Next, as the solid electrolyte film 46, a TaOx film is formed to a thickness of 500 to 900 nm, preferably 700 to 900 nm by plasma deposition. At this time, Ta ₂ O ₅ is used as a starting material, and film formation conditions are as follows:
Substrate temperature: 250 ° C
O ₂ gas partial pressure: 0.8 × 10 ⁻² Pa
Ar gas partial pressure: 3.5 × 10 ⁻² Pa
RF (high frequency) power: 600W
Set to. According to this, the film forming condition of the gas partial pressure when forming the Ta ₂ O ₅ film O ₂ gas partial pressure: 1.0 × 10 ⁻² Pa
Ar gas partial pressure: 3.3 × 10 ⁻² Pa
Since the O ₂ gas partial pressure is lower than that, a film lacking oxygen is formed, and a TaO x film (x is 2.10 to 2.45, preferably 2.30 to 2.45) 46 is formed. As a result of the TaOx film 46 being an oxygen-deficient film as compared with the Ta ₂ O ₅ film, in addition to ionic conductivity as a normal solid electrolytic film, electron leakage property (small electron conductivity, that is, large charge transfer resistance) is provided. can get. Further, since the Ar gas partial pressure is high, a large amount of Ar gas is taken into the TaOx film 46, and as a result, a porous TaOx film 46 is obtained. Since this porous gap is substituted with Ar gas and H ₂ O is taken in from the air, the TaOx film 46 contains more H ₂ O than a normal Ta ₂ O ₅ film.

(Step 4) Next, as the EC film 48, a WO ₃ film is formed by vapor deposition to a film thickness of 300 to 700 nm, preferably 500 to 700 nm. At this time, WO ₃ is used as a starting material, and film formation conditions are as follows:
Substrate temperature: 200 ° C
O ₂ gas partial pressure: 0.5 × 10 ⁻² Pa
RF (high frequency) power: Set to none. As a result, a WO ₃ film 48 (amorphous film) having an electron leakage property (a minute electron conductivity, that is, a large charge transfer resistance) in addition to the ion conductivity as a normal EC film can be obtained.

If the TaOx film 46 is electron leaking, even if the WO ₃ film 48 is formed normally (that is, under the same film forming conditions as the WO ₃ film for making a non-electron leaking EC element), It has been experimentally found that the EC element 40 can obtain an electron leakage property as a whole. Therefore, the WO ₃ film 48 can also be formed under the same film formation conditions as the WO ₃ film used to make a non-electron leaky EC element.

The WO ₃ film 48 can also be positively deposited with electron leakage. For example, the following various methods are conceivable.
<< Method 1 >>
The starting material for forming the WO ₃ film 48 is made of WO ₃ having a low purity. That performs Mo, Fe, Si, Al, a deposition of conductive powder such as Sn is mixed trace (for example, about 50 ppm) as impurities in WO _3. Thus, the conductive powder is incorporated into the formed WO ₃ film 48, WO ₃ film 48 becomes the electron leaky.
<< Method 2 >>
The crucible in the vapor deposition apparatus is always kept in a cleaning state in which some dirt (residue of the vapor deposition material WO ₃ after the previous vapor deposition) is left, and the vapor deposition material WO ₃ is placed in the crucible for vapor deposition. Alternatively, the crucible is cleaned cleanly as usual, and evaporation is performed by mixing a minimal amount of the residue of the evaporation material WO ₃ after the previous or previous deposition together with the WO ₃ of the evaporation material into this crucible. Accordingly, incorporated residue of the evaporation material WO ₃ within the formed WO ₃ film 48, WO ₃ film 48 becomes the electron leaky.
<< Method 3 >>
When heating the evaporation material WO ₃ with an electron beam in the evaporation apparatus, a sweep of the beam current is roughened. Thereby, the generated particles constituting the WO ₃ film 48 become large, and the WO ₃ film 48 becomes electron leaking.

(Step 5) Further, as the second transparent conductive film 50, an ITO film is formed to a film thickness of 200 nm by an ion plating method with the substrate temperature set at 250 ° C. The sheet resistance of the deposited ITO film 50 is 10Ω / □. Note that the second transparent conductive film 50 may be composed of an In ₂ O ₃ film, a SnO ₂ film, or the like instead of the ITO film. Further, as a method for forming the second transparent conductive film 50, a vapor deposition method, a sputtering method, or the like can be employed instead of the ion plating method.

  (Step 6) Clip electrodes 56 and 58 are respectively mounted using one side of the first transparent conductive film 44 of the EC element 40 before sealing and one side of the second transparent conductive film 50 on the opposite side as electrode extraction portions. As the clip electrodes 56 and 58, a spring-like phosphor bronze plate or a spring-like stainless steel is used.

(Step 7) When the clip electrodes 56 and 58 are mounted, the laminated film is sealed using an epoxy resin as the hygroscopic transparent sealing material 52. An example of a method for forming the hygroscopic transparent sealing material 52 using an epoxy resin will be described. Liquid epoxy resin main agent “Epicoat 807” (“Epicoat” is a registered trademark) manufactured by Japan Epoxy Resin Co., Ltd. and amine epoxy resin curing agent “Epomate B002” (“Epomate” is a registered trademark) manufactured by Japan Epoxy Resin Co., Ltd. Vacuum defoaming treatment is performed under 10 ⁻³ Pa for 5 hours. At this time, the amount of H ₂ O already adsorbed from the atmosphere at the main agent and curing agent stages can be kept constant. After mixing and stirring 100 parts by weight of the main agent and 50 parts by weight of the curing agent, the mixed solution is discharged or applied to one side of the transparent sealing substrate 54 with a dispenser, a flow coater, a spin coater or the like. Next, the transparent sealing substrate 54 is overlaid on the laminated film of the transparent substrate 42 so that the discharged or coated surface is opposed, and is heated and cured at 80 ° C. for 1 hour. The thus-prepared epoxy resin of the transparent sealing material 52 has a —OH group and is hygroscopic, and the H ₂ O adsorbed at the main agent and curing agent stage remains in the inside in almost the same amount. can do.

In addition, the hygroscopic transparent sealing material 52 can also be comprised with PVA and PVB instead of an epoxy resin. Since the hygroscopic transparent sealing material 52 composed of these materials has a trace amount of hygroscopicity, H ₂ O, H ⁺ , OH ⁻ can be retained internally.

(Step 8) The clip electrodes 56 and 58 and the lead wires 60 and 62 are joined by joining materials 61 and 63 such as solder and conductive adhesive, respectively. Thus, the EC element 40 of FIG. 1 is completed. The leakage current between the TaOx film 46 and the WO ₃ film 48 of the obtained EC element 40 was 0.2 mA at an erasing voltage of 1 V per 100 cm ² area.

FIG. 6 shows an example of the coloring / decoloring operation of the EC element 40 when the EC element 40 manufactured by the above steps is driven by the drive circuit of FIG. Here, when the drive voltage is applied to the EC element 40 so that the clip electrode 56 side is + polarity and the clip electrode 58 side is -polarity, the polarity of the drive voltage is +, and the polarity of the drive voltage is opposite. The symbol − indicates the case where the driving voltage in the coloring direction is + 1.8V and the driving voltage in the decoloring direction is −1.0V. When a coloring command is issued at time t1 (FIG. 6A), the switch 64 is connected to the contact a side (FIG. 6B), and a voltage of +1.8 V is continuously applied for 30 seconds (FIG. 6). 6 (c)), the transmittance of the EC element 40 rapidly decreases within this time, and reaches almost a steady state (20 to 25%) (FIG. 6 (d)). When the voltage application time of + 1.8V reaches 30 seconds, the switch 64 is switched to the contact b (open). When the switch 64 is opened, the EC element 40 has an electron leakage property. Therefore, the electric charge stored in the WO ₃ film 48 is gradually discharged, and the transmittance of the EC element 40 decreases. Therefore, when the opening time of the switch 64 reaches 0.5 seconds, the switch 64 is connected to the contact point a again, and a voltage of +1.8 V is applied for 2 seconds to compensate for the decrease in transmittance. The switch opening for 0.5 seconds and the voltage application of +1.8 V for 2 seconds are repeated during the period when the coloring command is given (during the period until the next decoloring command is given). Thus, the transmittance of the EC element 40 is kept substantially constant (20 to 25%) during the period when the coloring command is given. At this time, since the switching cycle of the switch 64 is short, the variation range of the transmittance is small, and the variation of the transmittance is not perceived by human eyes.

  When the command is switched from the coloring direction to the decoloring direction at time t2 (FIG. 6A), the switch 64 is connected to the contact c side (FIG. 6B), and a voltage of −1.0 V is continuously applied. Is applied for 15 seconds (FIG. 6C), and the transmittance of the EC element 40 rapidly rises within this time and reaches a substantially steady state (about 80 to 85%) (FIG. 6D). When the application time of the voltage of −1.0 V reaches 15 seconds, the switch 64 is switched to the contact b (open), and this switch open state is maintained until the next color command is switched.

In addition, the reaction formula at the time of coloring of the EC element 40 is as follows.

(WO ₃ film 48: cathode side)
WO ₃ (colorless) + xH ⁺ + xe ⁻ → HxWO ₃ (colored)

(TaOx film 46: anode side)
H ₂ O (moisture contained in the film) → H ⁺ + OH ⁻
OH ⁻ → (1/2) H ₂ O + (1/4) O ₂ ↑ + e ⁻

O ₂ ↑ (oxygen gas) generated from the TaOx film 46 by this reaction is taken into H ₂ O contained in the porous TaOx film 46, or the WO ₃ film 48 and the second transparent conductive film 50 Since it permeates and is taken into H ₂ O in the hygroscopic transparent sealing material 52 (epoxy resin) that retains H ₂ O, H ⁺ , and OH ⁻ internally, gas generation does not occur. Therefore, film peeling at the interface between the TaOx film 46 and the WO ₃ film 48 hardly occurs.

Further, when the EC element 40 is irradiated with sunlight during decoloring (the switch 64 is in an open state), hν (light energy) → H ⁺ (hole) + e ⁻ (electron) inside the WO ₃ film 48.
Although attempts wake of reaction, since the EC element 40 is an electronic leaky, e ^- of before the (electronic) e ^- for (electronic) properties are leaked through the TaOx film 46 and the WO ₃ film 48 , E ⁻ (electrons) is not generated. Accordingly, the corresponding H ⁺ (hole) is not generated, and coloring is prevented.

According to this embodiment, since the TaOx film 46 is porous, the WO ₃ film 48 formed thereon bites into the porous surface of the TaOx film 46, and the TaOx film 46 is anchored. And the WO ₃ film 48 become more adherent, and film peeling at the interface between the TaOx film 46 and the WO ₃ film 48 is less likely to occur. Further, by forming the TaOx film 46 by the plasma vapor deposition method, the binding between TaOx particles constituting the TaOx film 46 becomes strong, and a strong TaOx film 46 is obtained. Further, since the TaOx film 46 is porous, the interface contact area between the TaOx film 46 and the WO ₃ film 48 is widened, ion conductivity is increased, ion current is easily flowed, and coloring efficiency is increased (coloring is increased). (It becomes darker and the coloring speed becomes faster.)

(Embodiment 2)
Embodiment 2 of the EC element of the present invention is shown in FIG. The same reference numerals are used for portions common to those in Embodiment Mode 1 (FIG. 1). In the EC element 70, a reflective film / electrode film 72, a solid electrolyte film 46, an EC film 48, and a transparent conductive film 50 are sequentially stacked on a substrate 42 (not necessarily transparent), and further transparent conductive A transparent sealing substrate 54 is bonded onto the film 50 via a hygroscopic transparent sealing material 52 to constitute a reflection type EC element having the transparent sealing substrate 54 side as a whole as a surface side. Clip electrodes 56 and 58 are mounted on two opposing sides of the EC element 70. The clip electrode 56 is electrically connected to the reflective film / electrode film 72, and the clip electrode 58 is electrically connected to the transparent conductive film 50. A lead wire 60 is connected to the clip electrode 56 with a bonding material 61 such as solder or conductive adhesive, and a lead wire 62 is connected to the clip electrode 58 with a bonding material 63 such as solder or conductive adhesive. The EC element 70 can be configured as, for example, an anti-glare mirror for a vehicle.

In the second embodiment, the substrate 42 is made of a glass plate. The reflective film / electrode film 72 is made of Cr (chromium). The solid electrolyte membrane 46 is made of a porous TaOx (x is 2.10 to 2.45, preferably 2.30 to 2.45) having electron leakage. The EC film 48 is composed of a WO ₃ film having electron leakage. The transparent conductive film 50 is made of ITO. The hygroscopic transparent sealing material 52 is made of an epoxy resin. The transparent sealing substrate 54 is made of a transparent glass plate.

If the leak current value between the TaOx film 46 and the WO ₃ film 48 of the EC element 70 is too large, the memory performance is greatly reduced and the power consumption is large. Since the photochromic phenomenon cannot be prevented, 0.1 to 0.2 mA is preferable at an erasing voltage of 1 V per 100 cm ² area.

An example of a manufacturing process of the EC element 70 in FIG. 7 will be described.
(Step 1) On the surface of the substrate 42 formed of a glass plate having a size of 100 mm × 100 mm, a Cr film is formed as a reflective film and electrode film 72 to a film thickness of 80 to 150 nm by a sputtering method. The reflective film / electrode film 72 may be composed of an Rh film or the like instead of the Cr film. In addition, as a method for forming the reflective film and electrode film 72, a vapor deposition method, an ion plating method, or the like can be employed instead of the sputtering method.

(Step 2) After that, the same steps as (Step 2) to (Step 8) described in the first embodiment are sequentially performed to complete the EC element 70 of FIG. The leakage current between the TaOx film 46 and the WO ₃ film 48 of the obtained EC element 70 was 0.2 mA at an erasing voltage of 1 V per 100 cm ² area.

The EC element 70 in FIG. 7 can be driven in the same manner as in FIG. 6 by using a drive circuit having the same configuration as in FIG. However, since the EC element 40 in FIG. 1 includes both the first transparent conductive film 44 and the second transparent conductive film 50 made of metal oxide and has a higher electric resistance than metal,
Initial coloring voltage application: +1.8 V × 30 seconds Subsequent coloring voltage application: 0 V × 0.5 seconds + 1.8 V × 2 seconds repeated Decoloring voltage application: −1.0 V × 15 seconds In the case of the EC element 70 of FIG. 7, the reflective film / electrode film 72 is made of metal, and the electric resistance is lower than that of the metal oxide.
Initial coloring voltage application: +1.8 V × 15 seconds Subsequent coloring voltage application: 0 V × 0.5 seconds + 1.8 V × 2 seconds repeated Decoloring voltage application: −1.0 V × 10 seconds. With this drive,
Reflectivity during coloring: 10-15%
Reflectivity during decolorization: 50-55%
Is obtained. When the reflection film / electrode film 72 is formed of an Rh film instead of the Cr film, the reflectance is higher than this.

(Embodiment 3)
Embodiment 3 of the EC element of the present invention is shown in FIG. The same reference numerals are used for portions common to those in Embodiment Mode 1 (FIG. 1). In this EC element 74, a transparent conductive film 44, a solid electrolyte film 46, an EC film 48, and a reflective film / electrode film 76 are sequentially laminated on the transparent substrate 42, and further on the reflective film / electrode film 76. A sealing substrate 54 (not necessarily transparent) is bonded via a hygroscopic sealing material 52 (not necessarily transparent), and the reflective EC having the transparent substrate 42 side as a surface side as a whole is bonded. The element is configured. Clip electrodes 56 and 58 are mounted on two opposing sides of the EC element 74. The clip electrode 56 is electrically connected to the transparent conductive film 44, and the clip electrode 58 is electrically connected to the reflective film / electrode film 76. A lead wire 60 is connected to the clip electrode 56 with a bonding material 61 such as solder or conductive adhesive, and a lead wire 62 is connected to the clip electrode 58 with a bonding material 63 such as solder or conductive adhesive. The EC element 74 can be configured as an anti-glare mirror for a vehicle, for example.

In this Embodiment 3, the transparent substrate 42 is comprised with the transparent glass plate. The transparent conductive film 44 is made of ITO. The solid electrolyte membrane 46 is made of a porous TaOx (x is 2.10 to 2.45, preferably 2.30 to 2.45) having electron leakage. The EC film 48 is composed of a WO ₃ film having electron leakage. The reflective film / electrode film 76 is made of Al (aluminum). The hygroscopic sealing material 52 is made of an epoxy resin. The sealing substrate 54 is made of a glass plate.

If the leak current value between the TaOx film 46 and the WO ₃ film 48 of the EC element 74 is too large, the memory performance is greatly reduced and the power consumption is large. Since the photochromic phenomenon cannot be prevented, 0.1 to 0.2 mA is preferable at an erasing voltage of 1 V per 100 cm ² area.

An example of the manufacturing process of the EC element 74 in FIG. 8 will be described.
(Step 1) An ITO film is formed as the transparent conductive film 44 by the same step as (Step 1) described in the first embodiment.

  (Step 2) The edge portion 44a is separated from the transparent conductive film 44 by cutting the vicinity of the edge portion of the formed transparent conductive film 44 on the side where the clip electrode 58 is mounted by a photoetching method, a laser scribing method, or the like.

(Step 3) By performing the same steps as (Step 3) to (Step 4) described in the first embodiment, the TaOx film 46 and the WO ₃ film 48 are formed.

(Step 4) On the WO ₃ film 48, an Al film is formed as a reflective film and electrode film 76 to a film thickness of 100 nm by setting the substrate temperature to room temperature by an ion plating method. The edge 76 a on the side where the clip electrode 58 of the Al film 76 is attached is connected to the edge 44 a separated from the transparent conductive film 44. In addition, as a film-forming method of the reflective film and electrode film 76, an evaporation method, an ion plating method, or the like can be employed instead of the sputtering method.

(Step 5) Thereafter, the same steps as (Step 6) to (Step 8) described in the first embodiment are sequentially performed, whereby the EC element 74 of FIG. 8 is completed. The leakage current between the TaOx film 46 and the WO ₃ film 48 of the obtained EC element 74 was 0.2 mA at an erasing voltage of 1 V per 100 cm ² area.

The EC element 74 in FIG. 8 can be driven in the same manner as in FIG. 6 by using a drive circuit having the same configuration as in FIG. However, since the EC element 40 in FIG. 1 includes both the first transparent conductive film 44 and the second transparent conductive film 50 made of metal oxide and has a higher electric resistance than metal,
Application of coloring voltage at the beginning of the coloring instruction: +1.8 V × 30 seconds Application of subsequent coloring voltage: repetition of 0 V × 0.5 seconds + 1.8 V × 2 seconds Application of decoloring voltage: −1.0 V × 15 seconds However, in the case of the EC element 74 of FIG. 8, the reflective film / electrode film 76 is made of metal, and the electric resistance is lower than that of the metal oxide.
Application of coloring voltage at the beginning of the coloring instruction: +1.8 V × 15 seconds Application of subsequent coloring voltage: repetition of 0 V × 0.5 seconds + 1.8 V × 2 seconds Application of decoloring voltage: −1.0 V × 10 seconds To do. With this drive,
Reflectivity during coloring: 15-20%
Reflectivity during decolorization: 60-70%
Is obtained.

It is the top view and sectional drawing which show Embodiment 1 of EC element of this invention. It is the perspective view which shows the structure of the conventional EC element, and its drive circuit diagram. FIG. 3 is an equivalent circuit diagram of the EC element in FIG. 2. FIG. 2 is an equivalent circuit diagram of the EC element in FIG. 1. It is a figure which shows an example of the drive circuit of EC element of FIG. FIG. 6 is an operation waveform diagram showing an example of coloring / decoloring operation of the EC element 40 by the drive circuit of FIG. 5. It is sectional drawing which shows Embodiment 2 of EC element of this invention. It is sectional drawing which shows Embodiment 3 of EC element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 40 ... Transmission type | mold EC element, 42 ... Board | substrate, transparent substrate, 44 ... Transparent conductive film, 1st transparent conductive film, 46 ... Porous and electron leaking solid electrolyte membrane (TaOx film), 48 ... Electron leaking EC film (WO ₃ film), 50 ... transparent conductive film, second transparent conductive film, 52 ... sealing material, transparent sealing material, 54 ... sealing substrate, transparent sealing substrate, 70, 74 ... reflective EC element 72, 76: Reflecting film and electrode film.

Claims (8)

On the transparent substrate, a first transparent conductive film, a porous, electron-leakable solid electrolyte film, an electron-leakable electrochromic film, and a second transparent conductive film are sequentially laminated, and the second transparent conductive film An electrochromic element comprising a transparent encapsulating substrate and a transparent encapsulating material on the substrate, wherein a leakage current value between the solid electrolyte film and the electrochromic film is an area. It is 0.1 to 0.2 mA per 100 cm ² when the erasing voltage is 1 V, and is generated in the electrochromic film when receiving sunlight when erasing the application of the driving voltage. Electrons are discharged due to electron leakage of the solid electrolyte film and the electrochromic film, so that coloring of the electrochromic film due to a photochromic phenomenon is prevented. An electrochromic device in which the electron leakage property of the solid electrolyte membrane and the electrochromic membrane is set. A reflective film and electrode film, a porous, electron-leakable solid electrolyte film, an electron-leakage electrochromic film, and a transparent conductive film are sequentially laminated on the substrate, and a transparent film is formed on the transparent conductive film. An electrochromic element formed by attaching a transparent sealing substrate through a sealing material and configured to be a reflection type having the transparent sealing substrate side as a surface side, and between the solid electrolyte film and the electrochromic film The leakage current value is 0.1 to 0.2 mA at an erasing voltage of 1 V per area of 100 cm ² , and when the application of the driving voltage is stopped, the electro Electrons generated in the chromic film are discharged due to the electron leakage of the solid electrolyte film and the electrochromic film, and the electrochromic film is deposited by a photochromic phenomenon. An electrochromic device in which electron leakage of the solid electrolyte membrane and the electrochromic membrane is set so that color is prevented. On the transparent substrate, a transparent conductive film, a porous, electron-leakable solid electrolyte film, an electron-leakage electrochromic film, and a reflective film / electrode film are sequentially laminated, and the top of the reflective film / electrode film is formed. An electrochromic element comprising a sealing substrate and a reflective substrate with the transparent substrate side as a surface side, and a leak between the solid electrolyte film and the electrochromic film The electrochromic film has a current value of 0.1 to 0.2 mA at an erasing voltage of 1 V per area of 100 cm ² and is irradiated with sunlight during erasing when the application of the driving voltage is stopped. Electrons generated inside are discharged due to electron leakage of the solid electrolyte film and the electrochromic film, and the electrochromic film is colored by a photochromic phenomenon. An electrochromic element in which electron leakage of the solid electrolyte film and the electrochromic film is set so as to be prevented. The porous and electron-leakable solid electrolyte membrane is a TaOx (x is 2.10 to 2.45, preferably 2.30 to 2.45) film, and the thickness of the TaOx film is 500 to 900 nm, the electrochromic device according to preferably any one of claims 1-3 which is 700 to 900 nm. The electronic leakage of the electrochromic film is a WO ₃ film, the thickness of the WO ₃ film is 300 to 700 nm, preferably electrochromic device according to any one of the four claims 1 is 500~700nm . The sealing material is a sealing material having a hygroscopic property, the thickness of the sealing material is 50μm or more, electrochromic device according to preferably any one of claims 1-5 which is 50 to 500 [mu] m.   The electrochromic device according to claim 6, wherein the hygroscopic sealing material is an epoxy resin, PVA, or PVB. A method of driving according to the coloring instruction or decoloring command an electrochromic device according to any one of claims 1 to 7,
When a coloring command is issued, the driving voltage is continuously applied in the coloring direction for a predetermined time, and then the intermittent driving operation in which the driving of the driving voltage is stopped and then driven in the coloring direction is set to the predetermined period. Repeated in a cycle shorter than time,
A method for driving an electrochromic device, in which, when a decoloring command is subsequently issued, a driving voltage is continuously applied in a decoloring direction for a predetermined time and then the application of the driving voltage is stopped.

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