JPS61228422A - Electrochromic display element - Google Patents

Abstract

PURPOSE:To obtain an electrochromic display element having good optical characteristics by forming an thin org. film having electrochromic characteristics and a proton donor between transparent electrodes. CONSTITUTION:An electrolytic soln. is prepared by dissolving 5ml of aniline in an aq. soln. of 1M sulfuric acid, a quartz electrode coated with a 20nm thick vapor-deposited gold film is used for an anode, a tantalum metal plate is used for a cathode, and 0.3 A current is conducted at a voltage of 1.5 V. After conducting the current an about 0.5mum thick deep green film is formed on the anode in about 2sec, then, current is likewise conducted in an aq. soln. of 1M HCl by using the gold quartz electrode having this thin org. film as the cathode and the tantalum plate as the anode, resulting in changing color tone form the deep green to yellow in about 20msec, and, on the contrary, the color tone is restored from the yellow to the deep green in about 20msec by reversing the current direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to display devices, and particularly to electrochromic devices.

[Background of the invention]

They are classified into those that emit light themselves and those that do not emit light but modulate the surrounding light. The latter non-emissive type element has the advantage that it can be manufactured with low power consumption and can be directly driven by an integrated circuit. Incidentally, a non-emissive display element has a structure in which a liquid is sandwiched between two substrates. The devices currently in practical use are mainly liquid crystal display devices (LCD) and electrochromic display devices (ECD). Nematake type LCDs currently in use use polarized transmitted light due to the molecular orientation of liquid crystals, so they have poor display contrast due to brightness and darkness, have a narrow field of view that can be recognized, and can be used at low temperatures. There are problems such as insufficient response speed. On the other hand, there are organic and inorganic types of ECD, and the organic type uses viologen.
0-136000, and in inorganic systems, Wo
The most well-known one is the one using
46098), L is liberated, making it difficult to decolor, and the service life is too short for practical use. On the other hand, in the case of using Wo3, the ion diffusion speed in the W03 crystal is slow, and the response speed is essentially slow.

There is a drawback that the WO2 layer is electrolytically corroded by writing and erasing. There is a need for new display elements that do not have these drawbacks.

[Purpose of the invention]

An object of the present invention is to improve the above-mentioned drawbacks and provide an electrochromic display element having good optical properties.

[Summary of the invention]

Generating a Mohilner (D, M, Mohil)
ner) et al. in the Journal of the American Chemical Society (J, Aller, Chew,
Soc, 84 (1962) 3618).

On the other hand, in a basic solution, it has been found that a polymer film is formed on the anode electrode along with similar radicals (Bull et al. 1 Journal of Japanese and European Culture Studies).

Chew, Sac, Japan, ) 44. (1
971) 2960) The present inventor has discovered that a polymer thin film can be formed by an anodic reaction of aniline and aniline derivatives using tantalum, gold, or platinum electrodes even in weak acidity. Furthermore, after drying the formed electrode film, a negative charge of 0.5 to 1.5 V was applied in a protic electrolyte solution that did not contain aniline or aniline derivatives.
The absorption color changed from a deep green film to a yellow transparent film in a few tens of milliseconds. That is, electrochromic properties were observed. It was confirmed that this property has a memory effect and causes a change in color tone at low power. A similar effect is
(■) mentioned below.

It was also observed in aniline derivatives with structures such as (II) and (m). This reaction exhibiting electrochromic properties is caused by the polymer film 1b generated by anodic oxidation and its protons (
H4) The main reaction is an isomerization reaction with IC, which is an adduct.

Reaction (1) Hough 000A in 0.5 N hydrochloric acid solution
(7) When fabricated with a film thickness, stable operation was performed over 60,000 times with a switching time of 20 m5 ec.

This switching time is similar to that of conventional LCDs (100 to 30
0m5ec), ECD (100-500m5ec)
) is several times to an order of magnitude faster. Next, we attempted to create a solid-state device. An example of the element structure is shown in FIG.

This device uses a reaction between an immobilized enzyme membrane and a substrate dispersed and dissolved in the membrane as a proton supply source.

This reaction is a technology that has already been established as an enzyme sensor, for example, and is known to be highly reliable.The present invention is also characterized in that it is used as a proton supply source for display elements.

Preferred examples of organic substances used in the present invention include those represented by the general formula in addition to aniline. Examples of substituents for R1 and R2 are -H, -NH,,
-N)ICH, -N〆(CL)z --GO,H-8
o, H, -OCH, etc. In this case, both cases in which the substituents have the same substituent and cases in which they have different substituents are included. Specific examples include the following.

In addition, the compound of general formula (1) having one aromatic ring is R1
, R, one of which is preferably H, the general formula (
In the compound II) R1, R.

are shown attached to the same aromatic ring, but they may be attached one by one to different aromatic rings. Also, general formula (m)
In the compound, Rx -Rx are described as attached to separate aromatic rings, but it is also possible for R1, R, to be present on the - aromatic ring.

Moreover, the number of substituents may be three or more instead of two.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described, but the present invention is not limited thereto.

Example 1 5 cc of aniline is dissolved in a 1M sulfuric acid aqueous solution to prepare an electrolyte solution. In this solution, a quartz electrode with gold vapor deposited to a thickness of 200 mm was used as an anode, and a tantalum metal plate was used as a cathode.
V, a current of 0.3 A is applied.

As a result, a dark green film having a thickness of 0.5 μm was formed on the anode plate in about 2 seconds after the start of current application.

This membrane can be used for infrared absorption spectrum, ultraviolet-visible absorption spectrum, thin film chromatography and C,H.

N [By elementary analysis, mainly produced by the following reaction,
It is considered to be a polymer thin film having the structure 1b (R
=H).

几　　　　　　R shaku b In this reaction, R is CH, SO, H, OCH.

The same thing happened in other cases as well.

Next, the formed organic thin film was placed in a 1M hydrochloric acid aqueous solution at 1.5 V using the Au/quartz electrode having the organic film as a cathode and the tantalum plate as an anode.

When a current of 0.3 V was applied, a color change from deep green to yellow was observed at a speed of about 20 m5 ec.
FIG. 2 shows the spectral change of tone 0, in which the tone recovered from yellow to deep green at a speed of ec.

1b is a spectrum of 9 and 1c is a spectrum of 10.

Since this reversible change does not proceed in a neutral or basic atmosphere, the main reaction mechanism is thought to be the aforementioned H0. When the operating voltage was increased to 4V (0.5A), the switching time was increased to 20m5ec. However, the film became more likely to peel off.

Example 2 An example of an element structure is shown in FIG. 1 is CMOS/LSI
2 is a passivation film. 3
6 is a tantalum electrode, 6 is an Au/glass electrode with a film thickness of 200 mm, and 5 is an Au electrode by dissolving 3 cc of ortho-sulfanilic acid in 1 M sulfuric acid and applying currents of 1.5 V and 0.3 V. This is an organic electrochromic film formed on top of the organic electrochromic film. The film thickness is 7,000 people. 4 is a proton supply layer, which is formed of the following. A lipase enzyme, which is a lipolytic enzyme, is immobilized in a collagen gel membrane having a thickness of 1.3 mm, and at the same time, 10-''M of C3 R5 (COOCH3), a neutral lipid, is immobilized in a 0.2 cc aqueous solution.
) 3 was dispersed and included in a collagen gel membrane and used as a proton source. It is known that protons are generated in this membrane through the following reaction. An element having the structure shown in Fig. 1 was fabricated, and when a driving wave voltage of 2V was applied from the drive circuit 1 as shown in Fig. 3 for ΔT2 = 10 seconds, the deep It showed a color tone change between green and yellow. At this time, no gas was observed near both the Au/glass and tantalum electrodes. This is because the power consumption of the reaction is low, and therefore no gas is generated near the electrodes. This is thought to be because the amount of gas such as CH1 is small and dispersed and dissolved in the electrolyte layer.

In addition, similar devices were obtained when the aniline derivative was carried out not only with a compound having one aromatic ring but also with a compound having two or three aromatic rings as described above.

〔Effect of the invention〕

According to the present invention, it has a wide viewing angle, the color tone changes from deep green to light yellow, and is clear and beautiful, and the color changes can be performed at high speed in 50 milliseconds or less.
Further, it is possible to drive at a low voltage of 5 V or less, and has the effect of providing an inexpensive electrochromic display element.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of an electrochromic element, Fig.
The figure is an absorption spectrum diagram showing color tone change, No. 31iif
f is a periodic voltage waveform diagram. 1... Drive circuit, 2... Moisture-resistant membrane, 3... Electrode, 4
...Hydrogen ion supply source, 5...Organic thin film, 6...
Transparent electrode, 7...Glass carrier plate, 8...Transmitted light, 9,
10...Absorption spectrum. Part 1 t z ro 514 (Amendment to Gap Procedures)
Supplementary Showa 6% July 2981 ``0 Director General of the Patent Office Indication of 2 cases and supplementary 1985
Patent Application No. 68978 Relationship with the case of the person making the 3 amendments Patent applicant name (510)
Manufactured by Hitachi Co., Ltd. Shinshiki Ri Residence Address: 5-1 Marunouchi-chome, Chiyoda-ku, Tokyo 100 Hitachi Co., Ltd. Address: 212-1111 Tokyo (main representative) True content, No. 8 of the specification of the present application Correct rlMJ in line 3 of the page to "IN". , correct "IM" in the last line of page 8 to ro, INJ. , correct "IM" in the second line of page 10 by ro, lNJ.

Claims (1)

[Scope of Claims] 1. An electrochromic display characterized in that an organic thin film exhibiting electrochromic characteristics formed by electrolytic polymerization and a proton supply source is provided between electrode plates each having a transparent electrode on at least one side. element. 2. The organic thin film is an organic thin film formed by electrolytically polymerizing organic compound molecules having an aminobenzene ring structure with hydrogen at the para position in a protic electrolyte atmosphere. The electrochromic display element according to scope 1. 3. The electrochromic display element according to claim 1 or 2, wherein the proton supply source comprises an immobilized enzyme and a substrate.