JPS5963692A - Thin film el panel - 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 The present invention relates to a thin film EL/< channel having a double insulating film structure.

FIG. 1 shows a cross-sectional view of a thin film EL panel with a double insulating film structure. In FIG. 1, 1 is a transparent glass substrate, and a transparent electrode layer 2 is formed on the surface of this glass substrate 1. In FIG. This transparent electrode layer 2 is patterned into i number of electrode elements by an etching method such as In2O3. A first insulating layer 3 is formed on such a transparent electrode layer 2.
, a light emitting layer 4 and a second insulating layer 5 are sequentially formed. Then, a back electrode layer 6 is formed on the second insulating layer 5.

The back electrode layer 6 is made of aluminum and is patterned into a plurality of linear electrodes that intersect with the electrodes of the transparent electrode layer 2 by an etching method or a lift-off method. Note that 7 is a sealing plate that covers layers 3 to 6. By injecting moisture-proof oil 8 into the sealing plate 7 to make the thin-film EL panel moisture-proof, the thin-film EL panel is prevented from dielectric breakdown due to moisture.

In such a thin film EL panel, when a charge is applied between predetermined electrodes of the transparent electrode layer 2 and the back electrode layer 6, light is emitted at the intersections of the electrodes. The color of the emitted light varies depending on the material of the light emitting layer 4. For example, a light-emitting layer 4 made of ZnS as a matrix and with Mn as the light-emitting center emits yellow-orange light. The luminance of light emission varies depending on the charge applied to the transparent electrode layer 2 and the back electrode layer 6, that is, the potential difference.

In the thin film EI and panel as described above, the thickness of the first insulating layer 3, the light emitting layer 4, and the second insulating layer 5 is at most 1.
Very thin, 100 to 200 μm thick, on both sides of the thin layer.
Since a potential difference of V is applied, there is a risk of dielectric breakdown.

Therefore, it is necessary to form thin films of the first and second insulating layers 3 and 5 with good film quality and few defects.

By forming the first and second insulating layers 3.5 using a material with a high dielectric constant, a potential difference, that is, a driving voltage (hereinafter referred to as driving voltage) applied between the transparent electrode layer 2 and the back electrode layer 6 is created. can be lowered. Therefore, Y2O3 or Ta20. They used materials with high dielectric constants, such as According to these materials, the first and second insulating layers 3 and 5 can be formed using an electron beam evaporation apparatus and in the same vacuum as the light emitting layer 4. However, it is assumed that a defect 9 has occurred in the second insulating layer 5, as shown in FIG. 2, as shown in FIG. When this defect 9 occurs, the second insulating layer 5
When forming the back electrode layer 6 made of AJ on the surface of the third
As shown in the figure, Al enters the defect 9, and the light emitting layer 4 made of a semiconductor material such as ZnS and the back electrode layer 6 become electrically conductive. Further, if a defect similarly occurs in the first insulation N3, the material of the light emitting layer 4 enters the defect, and the light emitting layer 4 and the transparent electrode layer 2 become electrically connected. Eventually, if defects occur in the first and second insulating layers 3 and 5, the transparent electrode layer 2
The back electrode layer 6 becomes conductive. When a current flows, the defect 9 has a small cross-sectional area and a large resistance value, so that the electrode element of the back electrode layer 6 is damaged by Joule heat.

As a solution to this problem, the first and second insulating layers 3
, 5, it is conceivable to use Si, N, or the like, which can yield a thin film with relatively few defects.

However, Si and N4 have a small dielectric constant and have the disadvantage that the driving voltage cannot be lowered. Also, S i 3
Since N4 cannot be formed into a thin film without using the sputtering method, it cannot be formed in the same vacuum as the light emitting layer 4 formed by the steron beam evaporation method, which has the drawback of increasing the number of vacuum operations.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a thin film EL panel that can solve all of the conventional drawbacks.

Embodiments of the present invention will be described below with reference to the drawings. Fourth
The figure shows an embodiment of the invention.

In this figure, 11 is a transparent glass substrate (transparent substrate)
A transparent electrode layer 12 is formed on the surface of this glass substrate 110. This transparent electrode layer 12 is formed by a vapor deposition method.
For example, In2O formed to a film thickness of 00 to 3000
3 yoshi naru. Moreover, this transparent electrode layer 12 has a line width of 10
A plurality of linear electrode elements having a diameter of 0 to 400 .mu.m and a plurality of electrode elements arranged at equal pitches are patterned using an etching method.

A first insulating layer 13 is formed on such a transparent electrode layer 12. This first insulating layer 13 is made of, for example, Y2O,
Alternatively, if the film is made of a material having a high dielectric constant such as Ta205, the film thickness is 1 soo~6000.

A light emitting layer 14 is formed on the first insulating layer 13. This light-emitting layer 14 is made of, for example, Zns as a matrix and M
A light-emitting layer with n as the emission center, and 1500 to 5oo
It is formed to a film thickness of 100 mm. A second insulating layer 15 is formed on such a light emitting layer 14. This second insulating layer 15
is the same thin film as the first insulating layer 13. A metal oxide 16 is formed on this second insulating layer J5. moreover,
A back electrode layer 17 is formed on the metal oxide 16. This back electrode layer 17 is made of AII, for example. Further, this back electrode layer 17 includes a linear electrode element having a line width of 100 to 400 μm, which intersects the electrode element of the transparent electrode layer 12 at right angles;
Moreover, a plurality of electrode elements arranged at equal pitches are patterned using an etching method or a lift-off method.

In such a thin film EL panel, the layers from the transparent electrode layer 12 to the second insulating layer 15 can be formed using conventionally used forming methods. Moreover, the first insulating layer 13, the light-emitting layer 14, and the second insulating layer 15 can be successively formed in the same center using an electron beam evaporation device or the like.

After the formation of the second insulating layer 15 is completed in this manner, the metal oxide 16 and the back electrode layer 17 are then formed. These are created as follows. ' If the back electrode layer 17 is made of Al, A7I
The target is deposited by sputtering in a mixed gas atmosphere of O2 and Ar. As a result, the metal oxide 16 made of Al203 is formed to a thickness of several tens to hundreds of layers. Next, 0. Gas injection is stopped and A/ is sputtered in an Ar gas atmosphere. For this, Al120. Aj? A back electrode J consisting of
Form @17.

In this way, the metal oxide 16 and the back electrode layer 17 are formed. When forming the metal oxide 16 consisting of 20 g of AA by vapor-depositing AA in a mixed gas atmosphere of 02 and Ar, this metal oxide 16 As shown in FIG. 5, it is injected into a defect 18 formed in the second insulating layer 15. The metal oxide 16 made of Al2O3 is an insulating material. Therefore, even if a defective portion 18 occurs in the second insulating layer 15, by forming the metal oxide 16 as described above, the back electrode layer 17 and the light emitting layer 14 are completely insulated. .

As is clear from the above description, the metal oxide 1!5 is composed of an oxide of a metal material used as the back electrode layer 17. Therefore, the back electrode layer 17 has a small specific resistance value,
In addition, it is necessary to use a metal whose oxide is an insulating material.

Furthermore, the metal oxide 16 may be formed only between the second insulating layer 15 and the back electrode layer 17 as shown in FIGS. Insulating layer 1
It may be formed on the entire surface of 5.

Therefore, in the thin film EL channel as described above, when a voltage is applied between predetermined electrodes of the transparent electrode layer 12 and the back electrode layer 17, the luminescent center of the light emitting layer 140 is excited at the intersection of the electrodes. Emits light.

In addition, in FIG. 1, 1.19 is a sealing plate, and layer 1
3 to 15.17 and metal oxide 16. By injecting moisture-proof oil 20 into this sealing plate 19, the thin-film EL panel is made moisture-proof.

As is clear from the above embodiments, in the thin film EL panel of the present invention, the first and second insulating layers are formed of an insulating material with a high dielectric constant, and there is a gap between the second insulating layer and the back electrode layer. , an oxide of the metal material used as the back electrode layer is provided. Therefore, when an insulating material with a high dielectric constant is formed as a thin film, it is difficult to obtain a high-quality insulating film with few defects.However, in the present invention, even if defects occur in the second insulating layer, The oxide of the metal material used as the back electrode layer can reliably prevent conduction between the back electrode layer and the light emitting layer. Therefore, the conduction between the back electrode layer and the transparent electrode layer,
Furthermore, damage to the electrode elements of these electrode layers due to Joule heat can be prevented.

Furthermore, when forming the back electrode layer, 02 gas is injected as an atmospheric gas for sputtering, and 0, Ar and
It can be formed by a simple operation of creating a mixed gas atmosphere.

Further, in the present invention, the first and insulating layers are formed of an insulating material with a high dielectric constant. Therefore, the insulating layer is Si3
Compared to the case of forming with N, etc., manufacturing workability is improved and the driving voltage can be lowered.

The thin film E'L panel of the present invention having such effects can be used, for example, as a display panel.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional thin film EL panel, Fig. 2 is a partially enlarged view showing a defective part of the edge layer, and Fig. 3 is a partially enlarged view showing a part of the back electrode layer injected into the defective part. 4 is a cross-sectional view showing an example of the thin J1% EL panel of the present invention,
FIGS. 5 and 6 are partially enlarged views showing the state of formation of metal oxides. 11...Glass substrate, 12...Transparent electrode layer, 13.
...first insulating layer, 14...light emitting layer, 15...second
16... Metal oxide, 17... Back electrode layer. 1st WJ Figure 2 Figure 3 Figure 5 Figure 7 Figure 6 7

Claims (1)

[Claims] A transparent electrode layer including a plurality of electrode elements is formed on a transparent substrate, a first insulating layer, a light emitting layer, and a second insulating layer are sequentially formed on this transparent electrode layer, and the second insulating layer is In a thin-film EL panel having a double insulating film structure, in which a back electrode layer is formed on the layer and has a plurality of electrode elements patterned to intersect with the electrode elements of the transparent electrode layer, the first and second A thin film characterized in that the insulating layer is formed of an insulating material with a high dielectric constant, and an oxide of the metal material used as the back electrode layer is provided between the second insulating layer and the back electrode layer. EL panel.