JPH09161970A - Dot matrix type organic LED element - Google Patents

Abstract

(57) Abstract: In a conventional dot matrix type organic LED element, an anode electrode is laid in parallel on a transparent substrate, and a step larger than the film thickness of the light emitting organic layer is generated.
There is a problem that a short circuit accident occurs due to a break in the light emitting organic layer. According to the present invention, the film thickness t3 is [(thickness t1 of the anode electrode 3−insulating film 6 between the anode electrodes 3 and between the anode electrodes 3 and the end portion on the outer side in the longitudinal direction of the anode electrode 3). Film thickness t
3) absolute value] <(thickness t2 of light-emitting organic layer 4), the dot-matrix organic LE provided with the insulating film 6
Since the D element 1 is used, the step of the transparent substrate 2 and the anode electrode 3 generated on the laying surface of the luminescent organic layer 4 that exceeds the film thickness of the luminescent organic layer 4 is caused by the insulating film 6. The problem is solved by relaxing within the range of the film thickness of the layer 4 to prevent the film surface of the light emitting organic layer 4 from being interrupted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is also called injection electroluminescence (EL) and is an organic thin film EL.
The present invention relates to an organic LED element that emits light by injecting electrons and holes into a substance and recombining them. Specifically, the organic LED element has an electrode arrangement capable of driving in a dot matrix form to have a display function. It is related to.

[0002]

2. Description of the Related Art FIGS. 4 and 5 show examples of the structure of a conventional dot matrix type organic LED element 90 of this type.
On a transparent substrate 91 formed of a transparent member such as glass or resin, a plurality of anode electrodes 92 made of a transparent conductive member such as ITO are formed in parallel by a photolithography method or a screen printing method.

The anode electrode 92 of the transparent substrate 91
A luminescent organic layer 93 is formed by a screen printing method or the like on the surface on which the luminescent organic layer 93 is laid.
A plurality of cathode electrodes 94 made of a metal having a small work function, for example, a mixture of Mg: Ag, are laid on the upper surface of the above in parallel with each other in a direction orthogonal to the anode electrode 92.

Here, the light-emitting organic layer 93 is not necessarily a single layer, and may be any of a hole-injecting layer, a hole-transporting layer, a light-emitting layer, and an electron-injecting layer, each of which is made of an organic material. A functional layer is selected and configured as a layer including at least a light emitting layer.

[0005]

However, the dot-matrix organic LED element 90 having the above-described conventional structure is provided.
In the above, if the anode electrode 92 has an excessively high resistance, the voltage drop in the anode electrode 92 becomes remarkable and the efficiency as a whole is lowered.
It is usually formed as a film thickness of 000Å.

On the other hand, the luminescent organic layer 93 is 100
Since a film thickness of about 0 Å is common, the luminescent organic layer 93 is laid on an uneven surface that exceeds the film thickness of the luminescent organic layer 93 itself, as is clear from the sectional view shown in FIG. As a result, the cathode electrode 94 is also laid on the uneven surface.

At this time, if there is a portion on the side of the luminescent organic layer 93 where the film is not formed due to the above-mentioned unevenness of the surface, as shown in FIG. 6, the anode electrode 92 and the cathode are formed. The electrodes 94 come into contact with each other and cause a short circuit accident,
Further, as shown in FIG. 7, when a portion where the film is not formed is formed on the cathode electrode 94 side, a disconnection accident occurs in the cathode electrode 94, and in any case, the dot matrix type organic LED element. 90 is a defective product, which causes a problem that hinders productivity such as a reduction in yield, and it has been a problem to solve this problem.

[0008]

As a concrete means for solving the above-mentioned conventional problems, the present invention is a transparent substrate in which a plurality of anode electrodes are laid in parallel in one direction of either row or column. A dot-matrix organic LED device comprising: a light-emitting organic layer formed on the light-emitting organic layer; and a plurality of cathode electrodes arranged in parallel on the light-emitting organic layer in a direction orthogonal to the positive electrode. Of the thickness of the anode electrode and the end portion on the outer side in the longitudinal direction of the anode electrode.
An absolute value of (thickness of insulating film)] <(thickness of light emitting organic layer) is provided to provide a dot matrix type organic LED element, which solves the problem. Is.

[0009]

Next, the present invention will be described in detail with reference to an embodiment shown in the drawings. Reference numeral 1 in FIGS. 1 and 2
Indicates the dot matrix type organic L according to the present invention.
The organic LED element 1 is an ED element (hereinafter abbreviated as an organic LED element 1), and a plurality of anode electrodes 3 made of ITO or the like are formed on a transparent substrate 2 formed of a transparent member such as glass or resin of the organic LED element 1. It is the same as that of the conventional example in that it is laid in parallel with one of the rows.

A luminescent organic layer 4 is formed on the anode electrode 3, and a plurality of cathode electrodes 5 are formed on the upper surface of the luminescent organic layer 4 in a direction orthogonal to the anode electrode 3. However, according to the present invention, the gap between the respective anode electrodes 3 and the end portion of the outermost portion of the anode electrodes 3 on the outer side in the longitudinal direction are formed according to the present invention. The insulating film 6 is provided.

Here, when forming the insulating film 6, it is necessary to lay it in a relatively narrow space between the anode electrodes 3 with high precision, so it is preferable to form the insulating film 6 by a photolithography method or the like. Thus, a photosensitive resin such as photolithography can be SiO ₂ or ultraviolet curing is employed as a member of the insulating film 6. If the anode electrode 3 has a sufficiently large distance of 0.1 mm or more, it can be formed by a mask vapor deposition method. In this case, the insulating film 6 can be selected from a wider range. It will be possible.

Further, in the present invention, the film thickness t3 of the insulating film 6 is
The film thickness t3 of the insulating film 6 depends on the film thickness t1 of the anode electrode and the film thickness t2 of the light emitting organic layer 4 [(film thickness t1 of anode electrode-film of insulating film The absolute value of thickness t3)] <(thickness t2 of light-emitting organic layer) is satisfied.

Under the above conditions, the thickness t1 of the anode electrode 3 is 2
000Å, and the film thickness t2 of the luminescent organic layer 4 is 1000
More specifically, assuming that Å, the absolute value of the value obtained by subtracting the film thickness t3 of the insulating film 6 from the film thickness t1 of the anode electrode 3 (that is, 2000Å) is the luminescent organic layer 4 Does not exceed the film thickness t2 (that is, 1000Å) of the insulating film 6, that is, the film thickness t3 of the insulating film 6 is 1 under the above conditions.
More than 000Å and less than 3000Å.

In actual practice, the anode electrode 3
In consideration of variations in manufacturing the luminescent organic layer 4 and the like, a sufficient margin is expected, and the film thickness t3 of the insulating film 6 is 150.
It is preferable to set it to 0 Å or more and 2500 Å or less, and for example, as described later, for example, 18
The smaller the difference from the anode electrode 3, such as 00 Å or more and 2200 Å or less, the more preferable results can be obtained.

Next, the operation and effect of the present invention having the above-mentioned structure will be described. Between the anode electrodes 3 having a film thickness t1, the difference in level between the surface of the transparent substrate 2 and the top surface of the anode electrodes 3 emits light. The film thickness t that is smaller than the film thickness t2 of the organic layer 4
By providing the insulating film 6 of No. 3, in the organic LED element 1 of the present invention, the luminescent organic layer 4 laid on the upper surface of the anode electrode 3
Will be laid on an uneven surface having a film thickness t2 or less.

Therefore, even when the thickness t3 of the insulating film 6 is thinner than the thickness t1 of the anode electrode 3 as shown in FIG. 2, or as shown in FIG. Even when the film thickness t3 of the insulating film 6 is large, there is no portion where the film thickness is interrupted and the film is not formed due to the above-mentioned unevenness, whereby the anode electrode 3 and the cathode electrode 3 are not formed. Short-circuit accident with 5 can be completely prevented.

The fact that the unevenness of the uneven surface is reduced by the insulating film 6 eliminates the discontinuity of the film surface with respect to the light emitting organic layer 4 as described above, and further increases the upper surface of the light emitting organic layer 4. The unevenness of the surface of the cathode electrode 5 to be formed on the cathode electrode 5 is reduced, so that the film surface of the cathode electrode 5 is not interrupted and the disconnection accident of the cathode electrode 5 is prevented. Become.

[0018]

As described above, according to the present invention, the film thickness is defined as [(thickness of anode electrode-insulation- Absolute value of film thickness] <(film thickness of light emitting organic layer) The dot matrix type organic LED element provided with the insulating film is generated on the laying surface of the light emitting organic layer. The step difference between the transparent substrate and the anode electrode, which exceeds the film thickness of the light emitting organic layer, is mitigated within the range of the film thickness of the light emitting organic layer by the insulating film, which causes a break in the film surface of the light emitting organic layer. This prevents the occurrence of a short circuit accident between the anode electrode and the cathode electrode, or a breakage of the film surface of the cathode electrode, resulting in a disconnection accident. As a result, this kind of dot matrix type organic LED element is provided. It has an extremely excellent effect in improving the productivity and productivity. It is intended to.

[Brief description of the drawings]

FIG. 1 is a dot-matrix organic LED according to the present invention.
It is a top view showing one embodiment of an element.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view showing another embodiment of the dot-matrix organic LED element according to the present invention as a main part.

FIG. 4 is a plan view showing a conventional example.

FIG. 5 is a sectional view taken along line BB of FIG. 4;

FIG. 6 is an explanatory diagram showing an example of a short circuit accident that occurs in a conventional example.

FIG. 7 is an explanatory diagram showing an example of a disconnection accident that occurs in a conventional example.

[Explanation of symbols]

 1 ... Dot matrix type organic LED element 2 ... Transparent substrate 3 ... Anode electrode 4 ... Luminescent organic layer 5 ... Cathode electrode 6 ... Insulating film t1 ... Anode film thickness t2 ... Luminescent organic Thickness of layer t3 ... Thickness of insulating film

Claims (1)

[Claims] 1. A luminescent organic layer is formed on a transparent substrate on which a plurality of anode electrodes are laid in parallel in one direction of rows or columns, and the positive electrode is further formed on the luminescent organic layer. In a dot matrix type organic LED element in which a plurality of cathode electrodes are laid parallel to each other in a direction orthogonal to, a film thickness is set between each of the anode electrodes and an end portion on the outer side in the longitudinal direction of the anode electrodes. Absolute value of (thickness of anode electrode-thickness of insulating film)] <
The dot matrix type organic LED element is characterized in that an insulating film having a thickness (thickness of the light emitting organic layer) is provided.