JPH0217091B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrochromic coloring/eliminating device, and more particularly to an electrochromic coloring/eliminating device using a so-called electrochromic (hereinafter abbreviated as EC) substance.

[Prior Art] In recent years, electrochromic and decolorizing devices using EC substances have begun to be used as anti-glare mirrors, dimming windows, various display elements, and the like.

Such an electrochromic/erasable device is usually constructed by interposing an EC substance such as WO ₃ or MoO ₃ between electrode substrates and an electrolyte solution containing ions capable of coloring the EC substance.

As the electrolyte solution mentioned above, various compositions have been studied as systems containing H ⁺ or Li ⁺ with good conductivity, but typically, for example,
As described in Publication No. 138720, LiClO ₄
It is known that Li ⁺ ion source materials such as
Those using Li ₃ N and LiI are also known.

[Problems to be solved by the invention] The present inventors have proposed an invention that has already been applied for (Japanese Patent Application Laid-Open No.
30729) showed that a light control body using a transparent electrode as a counter electrode could be obtained by adding a redox agent to the electrolyte, but among the redox agents used in this study, an iodine ion source that ionized iodine ions It has been found that the material exhibits properties superior to other redox agents in terms of responsiveness and durability. However, when LiI is used as an iodine ion source material in the form of a solution,
When PC is used, CO ₂ gas is generated at high temperatures and further
Li ₂ CO ₃ precipitates and also when exposed to light
The drawback was that CO ₂ gas was generated. Also,
When an alcoholic solvent such as butyl alcohol (hereinafter abbreviated as BuOH) is used, the flat band potential of the surface of the EC substance, such as WO ₃ , in contact with the electrolyte solution changes in the positive direction when irradiated with light. The disadvantages were that it shifted and was easily colored by light, and that H ₂ gas was generated.

The present invention was made in order to eliminate the above-mentioned drawbacks of conventional electro-coloring and decoloring devices, and it is an electrolytic solution that uses an electrolyte solution that is thermally stable and does not cause phenomena such as foaming and coloring due to light. The purpose of the present invention is to provide a color erasing device.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and includes an EC material layer and an EC material layer between opposing electrode substrates.
In an electrochromic/erasing device comprising an electrolyte solution containing cation which colors an EC material layer,
An object of the present invention is to provide an electrochromic/erasing device characterized in that an electrolyte solution contains at least a lactone solvent and an iodine ion source substance.

The present invention will be explained in detail below.

The electrode substrate is made by coating, vapor depositing, or depositing a conductive transparent film such as SnO ₂ , In ₂ O ₃ or indium tin oxide (ITO) on the surface of a substrate such as glass or plastic.
An electrode formed by a known method such as sputtering is used. Note that in applications such as light control mirrors that do not require light to pass through the electrochromic/erasable device, one of the substrates does not need to be transparent and may be made of ceramic or metal such as Al. Alternatively, a reflective electrode such as TiN, ZrN, or HfN may be used as the electrode. Furthermore, when used as a light control mirror, both of the electrode substrates may be transparent, and a mirror surface may be formed on the back surface of one of the electrode substrates.

As the EC substance, known substances such as WO ₃ , MoO ₃ , TiO ₂ , Ir ₂ O ₃ and the like are used, but WO ₃ -based substances are preferable.

An iodine ion source substance is used as a redox agent for the electrolyte solution, and examples of the iodine ion source substance include metal iodides such as LiI and NaI, NH ₄ ,
Ammonium-based iodides such as (C ₂ H ₅ ) ₄ NI are used. When using ammonium-based iodide, etc. that does not contain cation, which develops the color of the EC material layer, it is necessary to add cations such as H ⁺ or Li ⁺ , which develop the color of the EC material layer, for ion implantation into the EC material layer. There is.

Such redox agents require a transparent or reflective counter electrode, and are used in electroluminescent devices such as dimming mirrors and dimming windows where opaque counter electrodes cannot be formed like normal display elements. Particularly effective results are obtained when used in decolorizing devices. Furthermore, when used as a small display, the electric coloring/decolorizing device of the present invention has a cycle life of more than 10 ⁶ coloring/decolorizing cycles, and is sufficiently durable for practical use as a display due to the ingenuity of the drive system. obtain.

As a solvent for dissolving the redox agent, lactone-based substances such as β-lactone, γ-lactone, and δ-lactone are used. An electrolyte solution is prepared by adding the above-mentioned iodine ion source substance from 0.001 M to saturation to this solvent. Among these lactone-based substances, lactones have a high boiling point and can be used at high temperatures, a high dielectric constant that dissolves a large amount of solutes and good conductivity, and a low freezing point that allows them to be used at low temperatures. γ-Butyrolactone (hereinafter abbreviated as γ-BL) has all the desirable properties as a solvent, such as being
is particularly desirable.

In addition, a thickener such as polyvinyl butyral (PVB), urethane, or acrylic polymer may be added to the electrolyte solution to gel the electrolyte solution.

[Example] Hereinafter, an electric coloring/decoloring device according to an example of the present invention will be described with reference to the cross-sectional view of FIG.

By vapor deposition method on a 10 cm square glass back substrate 3
A transparent electrode 4 is formed by coating an ITO film to a thickness of 1500 Å. Furthermore, a film thickness is formed on the transparent electrode 4 on the back substrate 3.
A 5000 Å thick WO ₃ film is deposited to form an EC material layer 5 .

Further, an ITO film is vapor-deposited to a thickness of 1500 Å on a 10 cm square glass front substrate 1 to form a transparent electrode 2.

A cell is formed by facing the front substrate 1 and the back substrate 3 so that the distance between the ITO film and the WO ₃ film is 200 μm.
An electrolyte solution 6 in which LiI was dissolved was injected and sealed with a sealing material 7 to produce a light control element 8.

The response speed of this light control element 8 from 80% to 20% coloring is 10 seconds at 0°C.
It also showed excellent characteristics in the cycle test and heat resistance tests shown in the figure.

That is, Fig. 2 is a graph showing data after a cycle test in which a voltage of ±1 V is applied to the electrodes of the dimming element for 1 minute each to repeat coloring and decoloring, and the vertical axis is the data after applying a voltage of 1 V for 1 minute. The amount of electricity injected, the horizontal axis shows the number of cycles, the data marked with 〇 is the data of the above example, and the data marked with △ is the data obtained by using PC as the solvent.
Data for a light control element using an electrolyte solution containing 0.5M/LiI dissolved, data marked with □ are for the solvent.
This is data for a light control element that uses BuOH and an electrolyte solution in which 0.5M/LiI is dissolved in BuOH. Note that the measurement was performed at room temperature, and the unit of the amount of electricity injected was [mC/cm ² ].

As is clear from the figure, as a redox agent
The light control device of this example using LiI and γ-BL as a solvent exhibited stable and high-speed response characteristics compared to devices using other solvents, and withstood a cycle test of 10 ⁵ times.

Figure 3 shows how the light control element is left outdoors and
This is a graph showing data from a test to examine resistance to use in natural environments such as rain, and is referred to as an outdoor exposure cycle test. The specimen, test method, etc. are the same as the cycle test shown in FIG.

In this test, the light control element using BuOH as a solvent foamed and stopped discoloring after ¹⁰³ cycles. Furthermore, in the light control element using PC as a solvent, the amount of electricity injected decreased extremely after 10 ² to 10 ³ cycles, and foaming occurred after 10 ⁵ cycles. Compared to these, the light control element of this example using γ-BL as a solvent showed a slight decrease in the amount of injected electricity after 10 ⁵ cycles, and exhibited sufficient practical characteristics without foaming. Ta.

Figure 4 shows the Weather O meter (hereinafter referred to as
(abbreviated as WOM), the horizontal axis is the WOM test time, the vertical axis is ±1V,
The amount of electricity injected when voltage is applied for 1 minute is shown. In this test, the light control elements using BuOH and PC as solvents foamed and stopped discoloring after 500 hours of testing. Compared to these, γ−
The light control element of this example using BL withstood a test of 2000 hours without foaming, and showed sufficient practicality.

Figure 5 is a graph showing heat resistance test data, and the horizontal axis shows the number of days left in an environment of 60°C.
The vertical axis shows the amount of electricity injected when a voltage of ±1 V is applied for 1 minute.

In this test, the light control element using PC as a solvent precipitated white powder after being left for 10 days and became unusable. In this test as well, the light control element of this example using γ-BL as a solvent exhibited high-speed response characteristics and was sufficiently practical to withstand heating for 30 days.

[Effects of the Invention] As explained above, the electrolytic coloring and decoloring device of the present invention uses an electrolyte solution in which an iodine ion source material is dissolved as a redox agent in a lactone solvent, so the response speed is fast and light It does not foam or reduce response speed even under adverse environments such as irradiation with ultraviolet rays, high temperatures, etc. It also withstands ¹⁰⁶ cycle tests and has sufficient weather resistance and durability.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
5 through 5 are graphs showing various test results of the embodiment shown in FIG. 1. DESCRIPTION OF SYMBOLS 1, 3... Substrate, 2, 4... Transparent electrode, 5... EC material layer, 6... Electrolyte solution, 7... Seal material, 8... Light control element.

Claims (1)

[Claims] 1. In an electrochromic/decolorizing device comprising an electrochromic material layer and an electrolyte solution containing cations that color the electrochromic material layer interposed between opposing electrode substrates, the electrolyte solution is small. 1. An electrochromic and decolorizing device characterized by containing a lactone-based solvent and an iodine ion source substance. 2. The electrochromic/erasable device according to claim 1, wherein the lactone solvent is γ-butyrolactone. 3. The electrochromic/decolorizing device according to claim 1 or 2, wherein the iodine ion source material is a metal iodide. 4. The electrochromic coloring and erasing device according to claim 3, wherein the metal iodide is lithium iodide. 5. The electrochromic and decolorizing device according to claim 1 or 2, wherein the iodine ion source material is an ammonium-based iodide.