JPS58114019A - Solid-state complementary type electrochromic display element - Google Patents

Abstract

PURPOSE:To make the display of the second of a time piece sufficiently possible and to increase the scale of integration of display patterns by disposing and laminating electrochromic layers, dielectric layers and electrodes symmetrically around the intermediate transparent electrode. CONSTITUTION:A lower transparent electrode 2 consisting of indium-tin oxide (ITO) of 2,000Angstrom film thickness and a WO3 layer 3 of 5,000Angstrom film thickness are laminated successively on a transparent electrode 1 consisting of soda lime glass of 0.7mm. thickness, and further a tantalum pentaoxide layer 4 (Ta2O5) of 4,000Angstrom film thickness, an Ir(OH)n layer 5 of 2,000Angstrom film thickness and an intermediate transparent electrode 6 consisting of ITO of 2,000Angstrom film thickness are laminated thereon by ion plating (IP), whereby the 1st display part is formed. Further, an Ir(OH)n layer 7, a Ta2O5 layer 9, a WO3 layer 9 and an upper transparent electrode 10 are laminated similarly thereon, whereby the 2nd display part is formed. The layers 3, 9 and the layer 5, 7 are formed to the same display pattern shapes.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display element to which an electrochemical coloring/decoloring phenomenon, that is, a gorectrochroming (hereinafter abbreviated as EC) phenomenon is applied, and more specifically, a reduction coloring type EC layer and an oxidation coloring type E.
The present invention relates to a solid-state complementary type GC display element characterized in that a dielectric layer is interposed between the C layers and the colored states of both EC layers are displayed in an overlapping manner when an external driving voltage is applied.

The structure of a conventional solid-state complementary EC display element has been proposed as follows. That is, after forming a lower transparent electrode on a transparent substrate, tungsten trioxide (hereinafter abbreviated as WO3) was formed.
A reduction coloring type EC layer mainly made of In(OH)n, a dielectric layer, an oxidation coloring type EC layer mainly made of iridium oxide (hereinafter abbreviated as In(OH)n), and a transparent electrode are sequentially laminated by vapor deposition or the like. By applying a voltage between the upper and lower transparent electrodes, both EC layers are simultaneously colored and erased. With this structure, compared to EC display elements using WO5 or [Ir(OH)n alone, it is possible to improve response speed, increase color density, and improve reliability. The application of is still not satisfactory. Furthermore, since the EC display element is originally driven by current, the pattern must be formed taking into account the resistance values of the upper and lower transparent electrodes, which has the disadvantage of poor display pattern integration.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks, and to provide a practical EC display element that is sufficiently capable of displaying seconds on a clock and has a high degree of display pattern integration. The present invention diversifies displays, improves color density, and extends life by arranging and laminating EC layers, dielectric layers, and electrodes symmetrically around an intermediate transparent electrode to form a dual complementary EC display section. This guarantees that This will be explained in detail below using examples.

Example 1 FIG. 1 shows a schematic cross-sectional view of the structure. A film with a thickness of 2000 mm was deposited on a transparent electrode 1 made of soda lime glass with a thickness of 0.7 m.
A lower transparent electrode 2 made of indium-tin oxide (hereinafter abbreviated as ITO), a layer 3 of WO with a thickness of 5000A, and a layer 3 of WO with a thickness of 5000A were successively laminated by vapor deposition, and further on top of this a layer 3 of WO with a thickness of 4000A was formed.
A tantalum pentoxide layer 4 (hereinafter abbreviated as Ta205), an Ir(OH)n layer 5 with a film thickness of 200A, and an intermediate transparent electrode 6 made of ITO with a film thickness of 200A are ion plated (hereinafter referred to as IP and abbreviated as "j"). The layers are laminated to form a first display section.Furthermore, the upper transparent electrode 10 is laminated in the same manner to form a second display section.
OH) n layer '5, T are formed in the same display pattern shape. By making the lower electrode 2 and the upper electrode 1o common and applying a driving voltage between them and the intermediate electrode 6, the first and second display sections can be colored and bleached simultaneously under exactly the same conditions. In this example, in the decolored state, all the constituent layers are transparent, and in the colored state, the two complementary EC display parts overlap, resulting in twice the coloration under the same driving conditions compared to the conventional complementary display element. concentration is obtained. Furthermore, in order to obtain the conventional coloring density according to this embodiment, the amount of charge injected into the first and second display sections may be 1/2 that of the conventional example. This situation is shown in FIG. FIG. 2 shows the relationship between the color density (optical density) and the amount of injected charge in a complementary EC display element. In the figure (A) is the driving condition of the conventional complementary EC display element,
(B) is the driving condition according to this embodiment. In order to extend the life of the device, it is desirable to drive the device in a range where the coloring density and the amount of charge injected are proportional. In this example, a completely proportional relationship was established, and there was no deterioration at all even after 107 cycles with IH7 drive. is not observed, and a significantly longer life can be achieved. Furthermore, a remarkable improvement was observed in response speed, and the relationship between coloring density and application time when a coloring voltage of 1.5 V was applied is shown in FIG.

In the figure, (A) shows the driving conditions of the conventional example, and (B) shows the driving conditions of the present embodiment.

In the conventional example, it takes 500 m5 to obtain a coloring density of 0.4'e.
According to this embodiment, 100 m5e is required compared to the required
Equivalent color density can be obtained with c. The response speed during decolorization also shows a similar tendency. Furthermore, since it is possible to drive in a low injection charge region compared to conventional methods, the applied voltage can be lowered, and ±I
Even V can display seconds with sufficient response speed.

Example 2 The device structure is shown in FIG. Transparent substrate 2 as in Example 1
1, a lower electrode 22, an intermediate electrode 26, an upper 8 electrode 30,
The WO layer 23.29, the Ta2Q5 layer 24.28, and the (r(OH)n layer 25.21) are laminated to form a first display section and a second display section to constitute a display element. In this example, The difference from the first embodiment is that the display pattern positions and shapes of the first display section and the second display section are not the same.In this embodiment, between the lower electrode 22 and the intermediate electrode 260, and between the intermediate electrode 26 and the upper electrode 30, By applying voltage to each, different patterns can be displayed.For example, the first display section can display the normal time, and by switching to the second display section, it is possible to display functions such as alarm settings and timer display. This substantially improves the degree of integration.Also, since the image display sections are simultaneously driven and there are sections where coloring is layered and sections where only one display section is displayed, it is possible to display gradations, making it possible to diversify the display. .

As stated above, according to the present invention, the solid-state complementary type E can improve the degree of display integration, achieve diversification, and guarantee a long life.
A C display element can be provided. In the example of the present invention, the element was constructed by laminating three WO layers on the lower electrode, but a complementary EC display element having exactly the same function could also be obtained with a structure in which (r(OH)n) layers were laminated. It will be done.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an element structure showing an example according to the present invention, FIG. 2 is a coloring density-injected charge characteristic diagram, FIG. 3 is a coloring concentration response characteristic diagram, and FIG. 4 is a diagram showing another example according to the present invention. FIG. 2 is a schematic cross-sectional view of an element structure showing an example. 3.9.23.29...WO, layer 6.26......
Intermediate electrode 5.7.25.27 ・= Ir(OH) n-layer Tomoe side Ekanomon Figure 4

Claims (1)

[Claims] A lower transparent electrode, one electrochromic layer of the reduction coloring type or the oxidation coloring type, a dielectric layer, the other electrochromic layer of the reduction coloring type or the oxidation coloring type, an intermediate transparent electrode, and the other electrochromic layer of the reduction coloring type or the oxidation coloring type are formed on a transparent substrate. The other electrochromic layer of the oxidation coloring type, a dielectric layer, a strong electrochromic layer of the reduction coloring type or oxidation coloring type, and an upper transparent electrode are laminated in order, and are formed between the lower transparent electrode and the intermediate transparent electrode. A solid-state complementary electrochromic display element comprising a complementary electrochromic display section and a second complementary electrochromic display section formed between an intermediate transparent electrode and an upper transparent electrode.