JPS5931548B2 - display material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display material for a display element.
The present invention relates to a display material for display elements that develops or changes color through an electrochemical redox reaction consisting of one or more 2'-dipyridyl derivatives.

In recent years, as the digitalization of display devices has progressed, various display materials have been developed, including liquid crystals, light emitting diodes, and materials exhibiting the so-called electrothalomism phenomenon that develops or changes color through electrochemical redox reactions. There are display elements using EC materials (hereinafter referred to as EC materials).

Conventionally, such EC substances include viologen represented by the general formula [wherein R is an alkyl group and X- is a monovalent anion] or Soviet Patent No. 324
583 specification or Japanese Patent Laid-Open No. 51-107151 are known.

However, viologen has the disadvantage that even if the type of alkyl group is changed, the color of the colored substance remains purple or reddish-purple, with almost no change in color, and therefore only a single-color display element can be obtained. On the other hand, the above-mentioned Soviet Patent No. 324583 or Japanese Patent Application Laid-Open No. 5110715
The EC material disclosed in Publication No. 1 has physical operating characteristics such as operational response and adhesion of color to electrodes during operation, which are inferior to 4,4'-dipyridyl-based EC materials typified by viologen. This poses a problem in use even though green display is possible. In view of the above, the present inventors have provided an EC material that has good physical operating characteristics, is capable of green display, has low power consumption for display, and can be widely applied to small to large display elements. The present invention was completed as a result of various researches.

That is, the present invention can be applied to the general formula: or [in both formulas, R and ~R8 each represent either a hydrogen atom or a lower alkyl group, and This is a display material for a display element that develops or changes color through an electrochemical redox reaction consisting of one or more 2,27-dipyridyl derivatives represented by the following anion.

To use the EC material according to the present invention as a display element,
It is used for display elements that are sealed in a accommodating cell and equipped with two or more electrodes and driven by applying a voltage.
It is sealed in a cell as an aqueous solution with a concentration of 1.

However, in this case, an inert organic solvent that dissolves the supporting electrolyte and the display material according to the present invention may be used, and is not limited to an aqueous solution. Such organic solvents include methyl alcohol, ethyl alcohol, dimethyl sulfoxide,
Dimethylformamide and the like can be mentioned. The EC substance of the present invention is colorless when dissolved in water, but when reduced, it is represented by the following structural formula: [In both formulas, R1 to R8 and X- have the same meanings as above.] It becomes a green substance that is insoluble in water. Therefore, the green color of the electrode surface and the color of the solution have a very good contrast, making it possible to display a vivid green color.

Furthermore, the EC substance according to the present invention can be synthesized by the following method.

That is, a theoretical amount to a slight excess of 1,3-dihalogeno n-propane or a derivative thereof or 1,2-dihalogenocyclohexane or a derivative thereof per mole of 2,2/-dipyridyl is heated at 100 to 200°C in an inert solvent. At 1
Heat for 0 to 30 hours. The precipitated crystals are filtered out.

Thereafter, it is washed by a conventional method and, if necessary, purified by a recrystallization operation or the like. The method of measuring the operational response is to use a device that measures the rising slope of the reduction current as shown in FIG. 1 in order to determine whether the operational response is good or bad.

In Fig. 1, 1 is a cell for measuring the rising slope of reduction current, 2 is an electrode for measuring the rising slope of reduction current, 3 is a resistor for converting current to voltage, and 4 is an X-Y synchroscope (or X-Y recorder → , 5 is a voltage sweeper.For measurement, a solution of 0.05 mol/l EC substance is placed between the electrodes 2 and 2 in the cell 1, and the voltage sweeper 5 is used to apply a voltage of 10V/S.
Apply voltage up to 1.5 depending on the sweep speed of ec. The rising state of the reduction current at that time was measured with an X-Y synchroscope (or It was measured by determining the rising slope θ. By this measurement method, the 2,2'-dipyridyl-based EC substances disclosed in Soviet Patent No. 324,583 or Japanese Patent Application Laid-open No. 107151/1980 can be measured from 118 to
While it shows an operational response of 680 μA/V, that of the 2,2'-dipyridyl series according to the present invention has an operating response of 891-10 μA/V.
A voltage of 67 μA/V was obtained, and the operational response was greatly improved.

Thus, according to the present invention, physical operating characteristics are better than conventional 2,2'-dipyridyl-based EC materials, green display is possible, power consumption for display is low, and display elements from small to large sizes can be used. This provided an EC substance that can be widely applied.

The present invention will be specifically explained below with reference to Examples. In order to actually perform driving experiments on the display materials shown in each example, the experimental driving cells shown in FIGS. 3 and 4 were used. FIG. 3 is a plan view thereof, and FIG. 4 is a sectional view taken along the line -' in FIG. (e.g. SnO2 or In2O3 film), T is a spacer,
9 is a separator (for example, an inorganic or organic material with micropores), 10 is an injection part for a solution of a test display material, 11 is an electrode (for example, Ag, Pt, Ni, etc.), 12 is a substrate (for example, glass), and 13 is a polarity The changeover switch 14 is a battery. In the first experiment, a solution of the test display material was poured into the test display material solution injection part 10 of the experimental drive cell shown in FIGS. 3 and 4, and the transparent electrode 6 and the electrode 11 to drive the experimental drive cell and observe the display results, and further observe the erasing results by passing the current in the opposite direction by switching the polarity switch 13. I went there. Example 1 A 0.05 mol/l aqueous solution of an EC substance represented by the chemical structural formula: was prepared, and 0.1 mol/10
) One drop of KBr aqueous solution was added as a supporting electrolyte, and then (
The display material was prepared by adjusting the pH to 3 using HC2 (1:1).

When this display material was driven using the experimental drive cell shown in Figures 3 and 4, the operational response was good and a green display was shown, and erasing was possible when a reverse voltage was applied. .

Further, when this display material was placed in a cell using an apparatus for measuring the rising slope of the reduction current shown in FIG. 1, the rising slope of the reduction current was determined to be 891 μA/.

Example 2 A 0.1 mol/l aqueous solution of an EC substance represented by the chemical structural formula: was used as a display material.

When a voltage was applied to this display material in the same manner as in Example 1, it operated in the same manner as in Example 1, had a good response, and was able to obtain a green display.

Example 3 In Example 1, a green display with good operational response was obtained even when a solvent such as ethanol, methanol, dimethyl sulfoxide, or dimethyl formamide was used instead of water.

Example 4 A 0.1 mol/l aqueous solution of the EC substance shown in the chemical structural formula: was prepared,
Further, one drop of 0.1 mol/l KCI as a supporting electrolyte was added to 2 CC of this solution, and the pH was further adjusted to 4 with (1:1) HCI to prepare a display material.

When this display material was driven using the experimental drive cell shown in Figures 3 and 4, the operational response was good and a green display was shown, and erasing was possible when a reverse voltage was applied. .

Further, when this display material was placed in a cell using the device shown in FIG. 1 for measuring the rising slope of the reduction current, the rising slope of the reduction current was determined to be 913 μA/.

Example 5 A 0.1 mol/l aqueous solution of the EC substance shown in the chemical structural formula: was prepared,
Furthermore, one drop of 0.1 mol/l KBr aqueous solution was added as a supporting electrolyte to 2 CC of this solution, and then (1:1) H
CI was adjusted to pH 4 and used as a display material.

When this display material was sealed in the experimental drive cell shown in FIGS. 3 and 4 and a voltage (0.85) was applied, the operational response was good and a green display appeared.

Further, when this display material was placed in a cell using an apparatus for measuring the rising slope of the reduction current shown in FIG. 1, the rising slope of the reduction current was determined to be 1067 μA/.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an apparatus for measuring the rising slope of a reduction current for measuring the operational response of a display material for a display element that develops or changes color due to an electrochemical redox reaction of the present invention, and FIG. Figure 3 is a voltage-current characteristic diagram obtained by measuring the rising state of the reduction current with an X-Y syntaroscope or an X-Y recorder using the device of the present invention. FIG. 4 is a plan view of an experimental drive cell for conducting actual drive experiments on display materials, and is a cross-sectional view taken along line 17 of FIG. 3, showing an additional mechanism required for operation. 1...Cell for measuring the rising slope of reduction current, 2
...... Electrode for measuring the rising slope of reduction current, 3.
...Resistance for current-voltage conversion, 4...X-
Y synchronoscope (or X-Y recorder), 5...
...Voltage sweep device, 6...Transparent electrode, 7.
...Spacer 8...Glass substrate, 9
Separator 10... Test display material solution injection part, 11... Electrode, 12...
... Board, 13 ... Polarity switch, 1
4...Battery.

Claims (1)

[Claims] 1 General formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) or ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(II) [In both formulas, R_1 to R_8 are Each represents either a hydrogen atom or a lower alkyl group, and X^- represents a monovalent anion such as a halide, perchloric acid, or boron tetrafluoride. A display material for display elements that develops or changes color through an electrochemical redox reaction consisting of one or more types. 2. The display according to claim 1, which is used in a display element that is encapsulated in a cell capable of containing a 2,2'-dipyridyl derivative, is provided with two or more electrodes, and is driven by applying a voltage. Display materials for devices. 3. The display material for a display element according to claim 1 or 2, wherein the 2,2'-dipyridyl derivative is in the form of a solution. 4 Claim 3 in which the solution is water or an organic solvent
Display materials for display elements as described in Section 1. 5 The organic solvent is methyl alcohol, ethyl alcohol,
The display material for display elements according to claim 4, which is one or more of dimethyl sulfoxide and dimethyl formamide.