JPH0294286A - Thin film el panel - Google Patents

Abstract

PURPOSE:To improve productivity without causing the reliability reduction of an element by using dry gas as the inner atmosphere of an envelope and arranging a sheet-shaped moisture absorber between a back plate and the thin film EL element. CONSTITUTION:Band-shaped lower electrodes 22 are aligned in parallel on a front base 21, a lower insulating layer 23, a light emitting layer 24 and an upper insulating layer 25 are laminated in sequence, and band-shaped upper electrodes 26 are aligned in parallel in the direction perpendicular to the direction of the lower electrodes 22 to form an EL element 27. A sheet-shaped moisture absorber 28 is arranged on the upper electrodes 26 of the EL element 27, the degassing of the EL element 27 is thoroughly performed by heating and vacuuming to remove the residual moisture to the extent possible, then a back plate 30 and the front base 21 are stuck together in the dry gas atmosphere consisting of dry N2 gas or dry air. A thin film EL panel with the dry gas atmosphere 29 inside is obtained, and productivity can be improved without causing reliability reduction.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a thin film EL panel used in display devices such as personal computers and word processors.

<Prior Art> As shown in FIG. 4, a conventional thin film EL panel has a lower transparent electrode 3 on a glass substrate 2. Lower insulating layer 4. Light emitting layer 5.
Upper insulating layer 6. After sequentially forming the upper electrode 7 and the upper electrode 7, the EL
In order to prevent moisture from entering the element 1, a backing glass 8 was bonded to the back surface of the substrate 2 with an epoxy resin adhesive 9. In order to further ensure high reliability, the inside of the envelope is evacuated through the hole 12 of the back glass 8 to remove residual moisture, and then silica gel powder is applied to the space 10 between the EL element 1 and the back glass 8. and silicone oil 13 in which black powder was dispersed, and the hole 12 was sealed with a tall seal 11.

<Problems to be Solved by the Invention> Many steps and time are required to inject and seal silicone oil in which silica gel powder and black powder are dispersed into an envelope. Therefore, this has been a major obstacle to reducing the cost of thin film EL panels.

Means for Solving the Problems> The present invention has been made to solve the above problems, and includes a thin film E in an envelope consisting of a translucent front substrate and a back plate.
In a thin-film EL panel that incorporates an L element and performs display through the light-transmitting front substrate, the internal atmosphere of the envelope is dry gas, and a sheet-shaped EL panel is provided between the back plate and the thin-film EL element. The present invention provides a thin film EL panel in which a moisture absorber is arranged.

As described above, by filling the inside of the envelope with dry gas and placing a sheet-like moisture absorber between the back plate and the thin film EL element, the envelope can be bonded in a dry gas atmosphere. In addition, the sheet-like moisture absorber can be placed by simply inserting it between the front board and the back board during this bonding process, so the manufacturing process can be completed while maintaining the high reliability of the thin-film EL panel. It becomes possible to greatly simplify the process.

<Example> Hereinafter, the present invention will be described in detail based on the example shown in the drawings, but the present invention is not limited thereto. FIG. 1 is a configuration explanatory diagram showing an example of the present invention. be. In the figure, 21 is a transparent front substrate made of glass, 22 is a lower transparent electrode, 23 is a lower insulating layer, 24 is a light emitting layer, 25 is an upper insulating layer, 26 is an upper electrode, 28 is a sheet-like moisture absorber, 3
0 is a back plate made of glass.

Strip-shaped lower electrodes 22 are arranged in parallel at regular intervals on the front substrate 21, then a lower insulating layer 23, a light emitting layer 24, and an upper insulating layer 25 are sequentially laminated on the substrate 21, and then on the upper insulating layer 25. A strip-shaped upper electrode 26 is connected to the lower electrode 2.
arranged in parallel at regular intervals in two directions orthogonal to each other,
EL element 27 is configured. A sheet-like moisture absorber 28 is placed on the upper electrode of the EL element 27, and the temperature is raised (about 200° C.) and vacuum is drawn to ensure sufficient outgassing of the EL element 27 and remove as much residual moisture as possible. When the back plate 30 and the front substrate 21 are bonded together in a dry gas atmosphere consisting of dry N2 gas or dry air, a thin film EL panel having a dry gas atmosphere 29 inside is completed.

The sheet-like moisture absorber 28 is made of a sheet of organic polymers such as cellulose, polyethylene, polypropylene, polyester, polyvinyl alcohol, polyamide, droxyethyl cellulose, and carboquine methyl cellulose, and silica (SiCh) powder. 10-5
Typically, the sheet is dispersed at an areal density of 0.00 or 4'.Furthermore, the sheet may be in any form such as film, paper, nonwoven fabric, or woven fabric.

In the above embodiment, a dry gas atmosphere 29 is formed between the moisture absorber 28 and the back plate 30 or the upper electrode 26, but the present invention is not limited to this.
The moisture absorber 28 may be attached to the back plate 30 in advance, and the atmosphere 29 may be formed only on the upper electrode 26 side.
Also, the thickness of the moisture absorber 28 is the same as that of the upper electrode 26 and the back plate 30.
The moisture absorber 2 is configured to have a thickness equal to or slightly thicker than the minimum gap between the
8 may be held by the upper electrode 26 and the back plate 30.

FIGS. 2(a) to 2(c) show typical structural examples of the sheet-like moisture absorber used in the present invention. Figure 2 (
a) is an organic polymer nonwoven fabric 31 in which silica powder 32 is dispersed; FIG. 2(b) is an organic polymer film 33 bonded to the moisture absorber shown in FIG. 2(a);
FIG. 2(C) shows silica powder 3 on organic polymer film 33.
4 was applied. Figure 2(b) or Figure 2(
When using the sheet-like moisture absorber shown in c), if the organic polymer film 33 is placed on the EL element 27 side, the effect of moisture absorbed by the moisture absorber will be on the EL element 27 side.
effective.

In addition, the back plate 30 and the sheet-like moisture absorber 28 are colored black or a color close to black so that the background of the display surface appears black or a color close to black when viewed from the translucent front substrate 21 side. This improves contrast and improves display quality.

Figure 3 shows the characteristics of deterioration when thin-film EL panels with different amounts of silica (area density) contained in the sheet moisture absorber were manufactured as shown in Figure 1 and subjected to accelerated tests in a heated and humid atmosphere. It is a diagram. (d) in the figure is when there is no moisture absorber (silica powder), (e) in the figure is when the areal density of the silica powder is 12/i, and (f) in the figure is when the areal density of the silica powder is 10 r. /
lT? In the case of , the areal density of the silica powder is 500.
This is a deterioration curve in the case of light/silence. Furthermore, the broken line indicated by (h) in the figure indicates the limit at which the display quality begins to deteriorate. From this test result, it can be seen that when there is silica powder with an areal density of 1 (1/l/or more), the display quality life of the thin film EL panel is greatly extended. It is currently technically difficult to disperse powder, and it is not expected to be very effective.Therefore, the areal density of silica powder is 10 to 500?/rr?
It was confirmed that the amount was sufficient.

Although the case where the EL element is a dot matrix type element has been described in the above embodiment, the present invention is not limited thereto, and other types of EL elements such as a segment type EL element may be used.

<Effects of the Invention> The present invention eliminates the need for complicated processes such as oil filling, making the manufacturing process of thin film EL panels simple and short, making it possible to improve productivity and reduce costs. In addition, in this case, the reliability of the device does not deteriorate.

[Brief explanation of drawings]

FIG. 1 is an enlarged vertical cross-sectional view of essential parts of an embodiment of the present invention, FIGS. The figure is a characteristic diagram showing the state of deterioration of a thin film EL panel with respect to the amount of silica contained in the moisture absorber, and FIG. 4 is an enlarged vertical cross-sectional view of the main part of a conventional example.

Claims (1)

[Claims] 1. In a thin-film EL panel in which a thin-film EL element is built in an envelope consisting of a translucent front substrate and a back plate, and display is performed via the translucent front substrate, the internal atmosphere of the envelope is dry. A thin film EL panel characterized in that the gas is used as a gas, and a sheet-like moisture absorber is disposed between the back plate and the thin film EL element.