JPS60198521A - Electrochromic display element - Google Patents

Abstract

PURPOSE:To provide a wider applicable temp. range, longer life and reduced electric power consumption by providing two electrodes for impressing an electric field to a conductive layer consisting of a specific compd. and a voltage source for impressing a voltage between these electrodes. CONSTITUTION:Transparent electrode layers 4, 5 are respectively deposited on transparent glass substrates 2, 3 and both substrates 2, 3 are adhered to an L shape by an epoxy resin 6 with the layers 4, 5 positioned on the inside to form an electrode 1. The electrode 1 is inserted into a quartz cell 7 and a conductive acrylonitrile soln. is put therein; thereafter, the layers 4, 5 are connected to a DC power source 8 and silver paste is coated on the contact parts from the voltage source 8 with the layers 4, 5. When a voltage is impressed to the layer 5 as cathode, the heptyl biologen reductant changed from colorless heptyl viologen to a blue color is formed on the layer 5 side.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to electrochromic display devices (hereinafter referred to as ECDs).
).

BACKGROUND TECHNOLOGY AND PROBLEMS Various types of ECDs are known that utilize a phenomenon (electrochromism) in which color changes are caused by the application of an electric field. For example, in a solution type BCD, an aqueous solution or an organic solvent solution containing an electrochromic substance is used as the guide W and the waste.

Since organic solvent solutions have lower freezing points than aqueous solutions, ECUs using organic solvent solutions are advantageous in that they have a wider applicable temperature range and a higher voltage at which electrolysis of the solution begins. However, organic solvents have lower conductivity than water, so HCs constructed using organic solvents as the solvent for the conductive layer
In order to obtain a comprehensive response speed, the voltage applied to the electrodes must be higher than in the case of an aqueous solution.

A high applied voltage is unfavorable in terms of HCD life span, power consumption, dielectric breakdown, and the like. In the case of an aqueous solution, it is effective to add potassium ferrocyanide to lower the applied voltage and pressure. However, this compound is insoluble in organic solvents. Therefore, there has been a need for a suitable material for lowering the applied voltage in ECDs using organic solvent solutions in the conductive layer.

reactions need to occur simultaneously. The applied voltage for causing this redox reaction is approximately equal to the difference between the oxidation potential of the oxidation reaction and the reduction potential of the reduction reaction.

Therefore, substances that develop color or change color upon reduction (
In a BCD using a reduced EC substance (hereinafter referred to as a reduced EC substance), in order to lower the applied voltage, it is necessary to select a substance that has a low oxidation potential in the oxidation reaction.

Various reduced EC substances that can be used in organic solvents are known, but for example, heptyl viologen has a concentration of about -500
It starts to be reduced at mV (vs. 880 W).

Usually, the oxidation potential of an electrolyte in an organic solvent is 2 to 3 V.
Quaternary ammonium salts such as tetraethylammonium verchlorate are used. Therefore, the applied voltage necessary to cause dielectrochromism is determined by the oxidation potential of the quaternary ammonium salt, and a voltage of 2V or more is required.

OBJECTS OF THE INVENTION In view of the above-mentioned points, the present invention provides an ROD in which the conductive layer is a solvent or an organic solvent and the applied voltage is 1y or less.

Summary of the Invention The present inventors have investigated various materials that can be used in a conductive layer consisting of an organic solvent-reduced EC material-electrolyte system to lower the applied voltage that causes electrochromism to 1 V or less, and have found that the oxidation potential is appropriate.

It was discovered that it has good reversibility, is stable in the system when no voltage is applied, and that derivatives thereof are suitable, and have completed the present invention.

That is, 5 the present invention comprises a reduced EC substance, an electrolyte, a compound selected from the group consisting of ferrocene and its derivatives,
A conductive layer made of a specific solvent, two electrodes for applying an electric field to this conductive layer, and a voltage source for applying a voltage between these electrodes, and by applying an electric field between the electrodes. , relates to an ECD characterized in that the color tone of the conductive layer is changed. With this configuration, it is possible to obtain an ECD in which the applied voltage required to cause electrochromism is 1 V or less.

Examples of ferrocene derivatives include the following compounds and ferrocene polymers.

Examples of ferrocenylamine i, i'-ferrocenedicarboxylic acid and reduced Be substances include viologens such as heptyl viologen and polyxyl viologen, 2-ter
anthraquinones such as t-butyl-anthraquinone,
and a3. Examples include metal oxides such as MoO, and [J205.゛As an electrolyte, a tetraalkylammonium salt such as tetraethylammonium perchloride [(C2
H5)4NCno04], Tetraethylammonium tetrafluoroborate ((C2H5)4NBF4), Tetra7" + Lua 7 Mon'nia A Bar 01
y −) ((C41(9)4NCA'U4) and tetrabutylammonium tetrafluoroborate [(C
aHp)4NBF''4).

Examples of organic solvents include acetonitrile, propion carbonate, dimethyl sulfoxide, dimethylformamide, ethanol, and the like.

The electrolyte is used after being dissolved in an organic solvent. .

Although it is preferable to use ferrocene and its derivatives by dissolving them in an organic solvent, they can also be used by dispersing them in a polymer membrane and fixing this polymer membrane to the electrode surface on the anode side. Alternatively, a reduced EC substance can be applied and fixed on the cathode side electrode surface.

In the present invention, when the conductive layer is a solution, reduced EC
Substance 5810~1×10 M, Fz.

Sen or its derivatives at I x 10-5M to saturation and electrolyte at I x 10-' to 1. It can be used at concentrations in the OM range.

Embodiment 1 of the ECD of the present invention will be described below with reference to the drawings.

Example 1 This example was conducted to demonstrate the electrochromic properties of the conductive layer in the BCD of the present invention.

Figure 1 shows the electrode 1 used in this example, 9 mm x 5
Transparent i'ro on each Dmm transparent glass substrate 2.3
11IL pole layers 4 and 5 were applied, and both glass substrates 2.degree. 3 were bonded in an L-shape with epoxy resin 6, with each electrode layer 4I5 facing inside. Therefore, the electrode layers 4 and 5 are insulated with the epoxy resin 6. Bottom surface 10mm x 10mm,
Electrode 1 was inserted into a quartz cell having a height of 40 mm, and a conductive acrylonitrile solution having the following composition was added.

Hepnal viologen 0.01M Tetraethylammonium verchlorate 0.5M Ferrocene 0.01M Next, each electrode layer 4, 5 was connected to a DC voltage source 8. The contacts from the voltage source 8 to the electrode layers 4, 5 were coated with a silver base.

With this configuration, changes in the absorption spectrum and coloring response of the conductive solution due to voltage application were measured.

(1) Change in absorption spectrum In FIG. 2, a voltage was applied using the 'rL electrode layer 5 as a cathode. On the taNs side, a reduced heptyl viologen that turned blue was generated from colorless heptyl viologen. As a result of measuring the absorption spectrum of this reduced heptyl viologen, it has an absorption maximum at 600 nm, and ssonm and 6
(2) color responsiveness with a shoulder near 60 nm Based on the results of the absorption spectrum, the absorption maximum wavelength (starting voltage of absorbance change at 3QQnm,
That is, the coloring start voltage was measured. A double beam spectrophotometer was used for this measurement, and the cell shown in FIG. 2 containing the conductive solution was placed on the sample side, and the cell containing only acetonitrile was placed on the reference side. In this measurement, a case where no change in absorbance appeared even after applying a predetermined voltage and voltage for 10 seconds was determined to be no coloring response.

For comparison, coloring responsiveness was measured under the same conditions as in this example except that ferrocene was not used.

Therefore, by adding ferrocene, the coloring initiation voltage could be reduced by o, ssv. The oxidation potential at the anode is approximately 1.
2V (vs. 5aE), while ferrocene is 0.4V (vs. 8aE).
CE), and it is thought that this difference in potential caused the decrease in the applied voltage.

In this Example I, the L-shaped electrode was used because
This is to facilitate observation of changes on both electrode surfaces, and both electrode surfaces may be arranged in correspondence with each other.

Example 2 The ECD of this example is shown in FIG. In FIG. 4, a transparent glass substrate 1 on which transparent ITU electrode layers 9 and 10 are attached.
1.12 is fixed with an adhesive 13 through a spacer 14 to form a cell, and the electrode layers 9 and 10 are connected to a DC voltage source 15.
It is connected to the.

The spacing between the electrode layers 9.10 was 1 mm. An acrylonitrile solution having a composition of 0.01 M heptyl viologen, 0.5 M Oyo IJ ferrocene (j, 01 M) is sealed as a conductive layer 16 in the cell.The electrode layer 10 is used as a cathode (display electrode). ), and when an electric field was applied to the conductive layer 16 at a voltage of 0.8 V, the display electrode side turned blue with a coloring response time of 120 m5ec.
I was able to change this and display it. Furthermore, by applying a voltage in the opposite direction, this blue display reversibly changed to colorless.

Effects of the Invention According to the present invention, the coloring start applied voltage of the ECD is set to IVIM.
Therefore, it is possible to provide an ECD that has a wide applicable temperature range, a long life, reduced power consumption, and eliminates problems such as side reactions and dielectric breakdown caused by the applied voltage i.

[Brief explanation of the drawing]

Figures 1 and 2 show the electrode used in the first embodiment and the cell containing this electrode, respectively, Figure 3 shows the absorption spectrum of the colored species in the first embodiment, and Figure 4 shows the absorption spectrum of the colored species in the first embodiment. 2
An example is shown below. In addition, in the symbols used in the drawing ζ, 1...
...... Electrode 2.3... Glass substrate 4.5... Electrode layer 9.10... Electrode layer 11, 12... Glass substrate 16... Conductive layer. Agent Masaru Ueya Yoshio Tsuneko (Voluntary) Procedural Amendment 1, Indication of Case Patent Application No. 55763 of 1982 (218) Sony Corporation 5, Date of amendment order (date of optical transmission) 1972 month day 6,
Number of inventions increased by amendment 7, subject of amendment (1), rMoos on page 6 of the specification, second line from the bottom, U2
Correct O5J to [Mo0y,,V2O5J. (2), rIXlo ~1.0MJ on page 8, line 1
is corrected to "NX10-2M ~ saturation". (3) "Acrylonitrile" on page 8, lines 15 to 16 is corrected to "acetonitrile." (4), page 10, lines 7 to 3 from the bottom, "It is thought that ...... at the anode."
・(5) Correct "acrylonitrile" on page 11, lines 12 to 13 to read "acetonitrile". −1 above

Claims (1)

[Claims] A conductive layer consisting of a substance that develops or changes color upon reduction, an electrolyte, a compound selected from the group consisting of ferrocene and its derivatives, and an organic solvent, and two electrodes for applying an electric field to the conductive layer. and a voltage source that applies a voltage between these electrodes, and is configured to change the color tone of the conductive layer by applying an electric field between the electrodes. .