JPS63231896A - Manufacture of electrochromic display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrochromic display element that utilizes electrochemical coloring/decoloring phenomenon.

[Conventional technology]

Electrochromic display element (FSelectroch)
-romic Display Devices (hereinafter abbreviated as ECD) are used in so-called electrochromic displays, and they reversibly change color by applying a voltage to a substance and through an oxidation-reduction reaction that occurs on the electrode surface or near the electrode interface. This is a display element that applies the so-called electrochromism phenomenon in which light transmittance changes. Displays can be roughly divided into self-luminous types such as light-emitting diodes and non-luminescent types such as liquid crystals, and ECDs belong to the non-luminous type.

Although ECDs are visible from any angle and have good display quality, they consume less power than LCDs (Liquid Crystal Display Elements*).
The lifetime depends on the number of on-off cycles. Since multiplex drive (time-division drive) is difficult, applications such as transportation-related destination information boards, fare displays, hospital counter information, and various measuring instruments are being considered.

Materials that exhibit electrochromism include metal oxides such as WO3, and progress is being made in elucidating the mechanism of coloring and fading. On the other hand, organic electrochromic materials have also been widely studied, and for example, rare earth compounds such as sifthalodianine have features such as the ability to produce multiple colors.

ECD applies a voltage between a display electrode and a counter electrode that performs electrochromic operation, and repeats coloring and decoloring by controlling the applied voltage. In Japanese Patent Application No. 61-010622 previously filed by the applicant, there is an ITO (Indium Ti) film formed on a glass substrate.
(n 0xide) A BCD is shown in which a display electrode with an iron phthalocyanine electrochromic coloring layer deposited on a transparent electrode is arranged opposite to a counter electrode, and a liquid electrolyte made of, for example, a saturated KCI aqueous solution is arranged between the two electrodes. has been done.

Although solid electrolytes are also available as electrolytes, ECDs using liquid electrolytes have the advantage of excellent responsiveness.

[Problem that the invention seeks to solve]

However, in such a conventional BCD, since the electrochromic coloring layer 3 is in direct contact with the liquid electrolyte 5,
There was a problem in that the electrochromic color forming layer 3 swelled and the iron phthalocyanine easily peeled off, resulting in a shortened cycle life of the ECD.

The purpose of this invention is to
By improving the adhesion to the TO transparent electrode 2, the repeat life of the ECD can be improved.

[Means for solving problems]

According to the present invention, the above object is achieved by treating iron phthalocyanine with IT.
In the process of vapor deposition on the O transparent electrode 2, the substrate temperature of the ITO transparent electrode 2 is set to 100 to 200°C, preferably 150 to 200°C.
This is achieved by controlling the temperature to 170°C.

[Effect]

In the step of vapor depositing iron phthalocyanine on the ITO transparent electrode 2, by controlling the substrate temperature of the ITO transparent electrode 2 in this way, the phase state of the iron phthalocyanine vapor deposited layer deposited on the ITO transparent electrode 2 can be controlled. Iron phthalocyanine electrochromic coloring layer 3 and ITO
Adhesion with the transparent electrode 2 is improved, and the repeat life of the ECD can be improved.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings. FIG. 1 is a schematic sectional view of an ECD according to an embodiment of the present invention. In FIG. 1, 1 is a glass substrate. 2 is IT
(Indium Tin Oxide) Transparent. 3 is an electrochromic coloring layer consisting of a deposited layer of iron phthalocyanine (FePc). Glass substrate 1 and IT
The O transparent electrode 2 and the electrochromic coloring layer 3 constitute a display electrode 8.

4 is a counter electrode, 5 is a liquid electrolyte made of a saturated KCI aqueous solution, 6 is a spacer, and 7 is a seal portion for sealing between the display electrode 8, the counter electrode 4, and the spacer 6.

Such an ECD is manufactured as follows. A TO transparent electrode 2 is formed on a glass substrate 1 by sputtering. FePc is deposited to a thickness of about 100 OA on the ITO transparent electrode 2 by a vapor deposition method to form an electrochromic coloring layer 3. A display electrode 8 consisting of a glass substrate 1, a TO transparent electrode 2, and an electrochromic color forming layer 3 and a counter electrode 4 are opposed to each other via a spacer 6, and a liquid electrolyte 5 consisting of a saturated KCI aqueous solution is injected into the gap.

In the ECD manufactured in this way, an electrode potential of -2.5 V and 0V is applied to the display electrode 8 with respect to the counter electrode 4 between the display electrode 8 and the counter electrode 4.

When −2.5 V is applied, the electrochromic coloring layer 3 becomes red. When set to Ov, it returns to blue. In this way, by controlling the applied voltage, it is possible to repeatedly display red and blue. It is estimated that the following electrochemical reaction (1) occurs at the display electrode 8 due to the applied voltage.

FePc-)-nH+-1-ne = HnFePc-
・－・－－－－－・－－－－－－(11 (Blue: QV
) (Red: -2.5V) The color change of the ECD described above decreases with the number of repetitions, and its repetition life characteristics are largely related to the adhesion between the iron phthalocyanine electrochromic coloring layer 3 and the TO transparent electrode 2. This is related to the peeling of iron phthalocyanine from the ITO transparent electrode 2 as the iron phthalocyanine electrochromic color forming layer swells due to the saturated KCI aqueous solution passing through the display electrode 8 and the counter electrode 4. Therefore, it is estimated that it is possible to control the phase state of the iron phthalocyanine deposited layer by controlling the substrate temperature of the ITO transparent electrode 2 during the iron phthalocyanine deposition, and thereby the iron phthalocyanine electrochromic color forming layer 3 and the ITO transparent electrode 2 It can be expected that the adhesion will be improved and the repeat life of the ECD will be improved.

Therefore, the repeat life characteristics of ECD are determined as follows.
The repeated life characteristics of ECD with respect to the substrate temperature of the ITO transparent electrode 2 were evaluated.

That is, the repeated life characteristic of the ECD is such that the display electrode 8 of the ECD is held at -2.5 V and OV with respect to the counter electrode 4 for 2 seconds each, and the change in visible absorbance at a wavelength of 550 nm in one cycle is 0.7. The evaluation was based on the number of repetitions until the test was completed. Table 1 shows the results of the above-mentioned repeated life characteristics.

Table 1 As shown in Table 1, the substrate temperature of the TO transparent electrode 2 is 100°C to 200°C, preferably 150°C to 17°C.
It can be seen that the electrochromic color forming layer in which iron phthalocyanine is deposited at 0°C has excellent repeat life characteristics.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in a BCD having a liquid electrolyte between a display electrode and a counter electrode, the substrate temperature of the TO transparent electrode is adjusted to ~
By controlling the temperature to 200° C., the phase state of the iron phthalocyanine vapor deposited layer can be controlled, the adhesion between the iron phthalocyanine electrochromic coloring layer 3 and the ITO transparent electrode 2 can be improved, and the repeat life of ECD can be improved.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of an ECD according to an embodiment of the present invention. 1 glass substrate, 2: ITO transparent electrode, 3: electrochromic coloring layer, 4: counter electrode, 5: saturated KCI aqueous solution, 6: spacer, 7: sealing part, 8: display electrode. 1st (2)

Claims (1)

[Claims] A method for manufacturing an electrochromic display element, characterized in that in the step of vapor depositing iron phthalocyanine on the display electrode substrate, the substrate temperature of the display electrode substrate is set at 100 to 200°C.