JPS6147778A - Electrochromic display device - Google Patents

Abstract

PURPOSE:To obtain proper display color and high operation stability, by using a solution having dessolved a specific organic material and a support electrolyte and electrode substrates sandwiching the solution. CONSTITUTION:The aimed display device comprising the electrochromic solution 5 having dissolved a compound shown by the formula (R1 is H, alkyl, or aralkyl; R2, R3, R4, and R5 are H, alkyl, aralkyl, aryl, or cycloalkyl; in R1-R5, alkyl chain or aryl ring may be replaced) as an organic material capable of coloring and losing its color electrochemically reversibly and a support electrolyte, and a pair of the electrode plates 3 and 4 to sandwich the solution. The concentration of the organic material and the support electrolyte are preferably 0.01-1.0mol/l.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a display device, particularly an organic electrochromic (
The present invention relates to electrochromic display devices (hereinafter abbreviated as ECD) using EC materials.

(Prior art and its problems) Organic ECDs using organic EC materials can be multi-colored,
Although it is expected to be put into practical use because of its theoretical advantages such as clear images, it has not yet been put into practical use. The first main reason for this is insufficient operational stability. Typical organic ECDs that have been proposed and currently under development use viologen as the EC material (see literature
Letters (Appl, Phys, Lett, 23
(1973), P64) is a stable operating 0N-
According to our test results, the OFF cycle life is only about 10 times, which is insufficient compared to the minimum practical life of 106 times. The cause of this operational deterioration is the coloring-decoloring (ON-OF)
It is said that this is due to incomplete reversibility of the biosegen precipitation-redissolution phenomenon associated with F), but the exact details are unknown. The second reason is that the displayed color is purple, which is unique to the viologen type.
This is the point where it is not possible to fully meet the market demand for diversification of display colors. Furthermore, the purple color of viologen is not necessarily appropriate as a standard display color, which is one of the reasons why it is not accepted by the market.

(Objective of the Invention) An object of the present invention is to provide a novel organic ECD which has a display color suitable for a display device and also has stable reversible coloring and decoloring operations.

(Structure of the Invention) The electrochromic display device of the present invention includes an electrochromic display device that includes a solution in which an organic material and a supporting electrolyte that can be electrochemically reversibly colored and erased are dissolved, and a pair of electrode substrates that sandwich the solution. In the indicated amount, the organic material is the following compound (I) [wherein R□ is a hydrogen atom, an alkyl group, an aralkyl group,
R, I R,, R41R, are hydrogen atoms and alkyl groups.

Indicates an aralkyl group, an aryl group, and a cycloalkyl group.

In the substituents Rt, Rt, Rs, and R4-Rs, the alkyl chain and aryl ring may be substituted.

] It is distinctive in that it includes.

(Example 1) The present invention will be described below based on examples together with drawings. The figure is a sectional view showing an embodiment of the display device of the present invention.

In the figure, 1 and 2 are glass substrates, 3 is a display electrode made of an ITO (indium tin oxide) film or a tin oxide (Snow) film, and 4 is a metal film such as ITO, 5nOz or stainless steel, platinum, or carbon or iron complex. 5 is a counter electrode consisting of a pressed film of a mixture of
C is an EC solution in which material and supporting salt are dissolved; 6 is a porous light scattering material such as a ceramic thin plate such as alumina or a polymer thin plate. The electrode substrate consists of a glass substrate and an electrode. As the porous light scattering material, titanium oxide ('
An insulating or semiconducting white powder such as e-alumina (AA!, O,) may also be used. As the EC solution material, any solvent can be used as long as it has high polarity and is electrochemically stable. In addition to water, propylene carbonate, dimethylformamide, N-methyl-2
- A non-aqueous solvent such as pyrrolidone is used.

In the present invention, non-aqueous solvents are particularly suitable, and in this example,
Propylene carbonate was used. The supporting salt is an alkali metal for non-aqueous solvents.

Quaternary ammonium and perchloric acid CZO, halogen.

Fluoroborate BF4. Fluorophosphate PF
A salt with a is used. For water, ordinary inorganic salts can be used. In an example of the present invention, tetrabutyl fluoroborate (N(nu)4BF'4) was added at a concentration of g, 5 m
oJ/A! It was used to a certain degree. As the EC material, the following compound A was used at a concentration of 0.2 no/l. The above EC materials,
The concentration of the supporting salt is not limited to the above concentration, and may vary depending on the solvent used, the characteristics of the electrolyte, and the required display performance.
．． It can be selected within a range of about 0.01 to 1.0 mol/l.

Display electrode 3 and counter electrode 4 of a display device having such a configuration
In between, a voltage of 1.2 to 1.0 is applied so that the display electrode 3 side becomes positive voltage.
When 5V is applied, the display surface shows a clear green color on a white background. Moreover, when the applied voltage was increased to +1.8 to 2.2 V, a clear bluish-green color was developed. Further increase the voltage to Ov
Or, if you reverse the polarity, the color will disappear.

As mentioned above, the ECD using the present compound A has an applied voltage of 1
．． 2-1.5V, 1.8-2. Green by changing it to OV.

It also has the feature of being able to obtain two different display colors, including blue-green. When this device was tested for repeated coloring and decoloring operations, almost no electrochemical deterioration was observed even after being used for at least 106 times.
The stability of the solution was found to be very high. (Example 2) The procedure was the same as in Example 1 except that 4,4'-bis(dimethyl)-N-methyldiphenylamine was used as the EC material. The results were similar to Example 1.

(Example 3) 4,4'-bis(isopropylamino) as EC material
The procedure was the same as in Example 1 except that diphenylamine was used. Similar results to Example 1 were obtained.

ECs that can be used in the present invention in addition to the above embodiments
Examples of materials include 4,4″-bis(phenylamino)diphenylamine, 4-(dimethylamino)-4′-(isopropylamine)-N-methyldiphenylamine, 4-(
(dimethylamino)-4'1(1-methylhexylamino)diphenylamine and the like.

(Effects of the Invention) As described above, the ECD of Example 0 can display green and patina, which are the display colors generally requested by customers, and has high operational stability and excellent reliability. ECD
It becomes possible to provide the following.

[Brief explanation of the drawing]

The figure shows an embodiment of the present invention. In the figure, 1°2 is a glass substrate, 3 is a display electrode, and 4 is a counter electrode. 5 is an EC solution, and 6 is a porous light scatterer. 12...Glass substrate 3...Display electrode 4...Counter electrode 5...EC solution 6...Porous metal

Claims (1)

[Scope of Claims] An electrochromic display device comprising a solution in which an organic material capable of electrochemically reversibly coloring and decoloring and a supporting electrolyte are dissolved, and a pair of electrode substrates sandwiching the solution, wherein the organic material An electrochromic display device comprising the following compound (I). (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [In the formula, R_1 is a hydrogen atom, an alkyl group, an aralkyl group, R_2, R_3, R_4, R_5 are a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, a cycloalkyl group. Indicates the group. Substituents R_1, R_2, R_3, R_4, R_5
In the above, the alkyl chain and aryl ring may be substituted. ]