JPH0143933B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of manufacturing an electrochromic display. In recent years, electrochromic materials such as _WO3 ,
Electrochromic display devices (hereinafter referred to as ECDs) that utilize electrochemical redox reactions of transition metal oxides such as MoO ₃ have been developed. It takes
The general structure of an ECD is to form a transparent conductive film 2 of indium oxide or tin oxide on a transparent substrate 1, as shown in FIG. A tungsten oxide (WO ₃ ) film 3 is deposited to form a display electrode. Further, as shown in FIG. 1B, in order to protect the transparent conductive film 2, an insulating protective film 4 may be provided on the conductive film other than the display area (WO ₃ ). Conventionally, the display part of such an ECD display pole (e.g.
Patterning of WO ₃ ) is generally done during vapor deposition using a metal mask, but in this case,
It has the disadvantage that the mechanical mask overlay error is large, and the film thickness around the pattern is not uniform, resulting in display blur. Therefore, when a highly accurate pattern is required, a method is used in which an electrochromic material is deposited on the entire surface and then patterned by etching. Methods for etching transition metal oxides (eg, WO ₃ , MoO ₃ ) mainly include chemical methods, plasma methods, and reactive sputtering methods. Chemical etching is a method that is easier to mass produce and is cheaper than other methods, but it has traditionally been difficult to use due to the large side etching (shown at 6 in Figure 1b) and the fact that the substrate is contaminated with metal residue from the etching material. It was difficult. The present invention has discovered an etching material that causes less side etching and no metal residue after etching in a chemical etching method for patterning a display area. It provides ECD. Hereinafter, one embodiment of the present invention will be described with reference to the drawings. (Example 1) Figure 2e shows a cross section of essential parts of an example of an EC cell manufactured by the manufacturing method of the present invention. In the figure, 1 is a transparent substrate, 2 is a transparent conductive film such as In ₂ O ₃ or SnO ₂ , 3 is teeth
A transition metal oxide EC layer such as WO ₃ or MoO ₃ , 4 an insulating protective film such as silicon oxide or MgF ₂ , and 5 a resist. Figures 2a to 2e are WO ₃ membranes according to an example of the present invention.
FIG. 3 is an explanatory diagram for explaining a display electrode creation process when using ECD. Each step will be explained below. (a) First, a transparent conductive film 2 made of In ₂ O ₃ is formed on a glass substrate 1, and a WO ₃ film 3 of about 3000 Å is formed on the substrate surface by a vapor deposition method. (b) Furthermore, a resist 5 such as a screen resin resist or a photo-etching resist is created in the shape of a display pattern. Preferably, the resist 5 is a positive type resist that can be easily subjected to a subsequent peeling process. (c) This step is an etching step to pattern the WO ₃ film. Etching material is NH ₄ Cl―
This is done using a mixed aqueous solution of NH ₄ OH (about PH10). The side etching at this time was about 1 μm. After etching, the substrate is washed with running water. (d) Insulating film coating process. Form SiO by a vapor deposition method. (e) This step is a step in which the resist is removed and the insulating protective film is lift-off etched at the same time. In the above steps (a) to (e), it is possible to control the side etching (overetch) of the WO ₃ film to about 1 μm, there is no metal residue in the WO ₃ etching process, and the display has good display memory properties. The pole was obtained. (Example 2) Table 1 shows the degree of side etching of the WO ₃ film and the degree of display memory due to metal residue by changing the etching material in the same display electrode manufacturing process as in Example 1.

[Table] As is clear from Table 1, when WO ₃ was etched using an alkaline organic compound aqueous solution (No. 5 to No. 10) as an etching material, when a conventional alkali metal base was used (No. 1 to No. 4), it was found that side etching could be controlled to 1 μm or less, and a display electrode with good display memory properties could be obtained without contaminating the substrate with metal residue. A similar effect was also observed in the patterning of the display electrode when MoO ₃ was used as the EC material. As explained above, the present invention enables patterning of display electrodes to be performed with high precision using chemical etching, thereby eliminating problems with display quality.
This provides an inexpensive ECD that is highly mass-producible.

[Brief explanation of drawings]

Figures 1a and 1b are cross-sectional views of the main parts of a conventional EC cell.
FIGS. 2a to 2e are explanatory diagrams of the manufacturing process of an EC cell according to the ECD of the present invention. 1...Transparent substrate, 2...Transparent conductive film, 3...EC layer,
4... Insulating protective film, 5... Resist.

Claims (1)

[Claims] 1. An electrochromic layer is provided on a transparent conductive film provided on a transparent substrate, and the electrochromic layer is selectively etched with a solution containing ammonium ions or amines, and the remaining electrochromic layer is used as a display electrode. A method of manufacturing an electrochromic display device, characterized by: