JP2003264064A - Luminescence display device, organic el display device and manufacturing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform a good signal supply by lowering electric resistance of a connection portion with an electrode of a light emitting element and an extraction electrode. <P>SOLUTION: By laminating a first electrode 2, an organic layer 3, and a second electrode 4 one by one on a transparent substrate 1, an organic EL element is formed, and by forming the connection portion S of a metal electrode 4L, with which the second electrode 4 is formed in a sealing component 8, and the metal extraction electrode layer 6, a melting joint portion 9a is formed in this connection portion S by laser beam irradiation. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting display device in which an extraction electrode for supplying a display signal is connected to an electrode in a light emitting element, an organic EL display device which is one of the light emitting display devices, and its manufacture. It is about the method.

[0002]

2. Description of the Related Art Various types of self-luminous light emitting display devices have been developed in recent years, but the basic structure is such that a light emitting element that can be driven with or without lighting is used as an element. It is arranged in a plane. Examples of such a light emitting display device include a VDP (Vacuum Fluorescence Display) including a PDP (Plasma Display Panel) using cells divided by a discharge space as light emitting elements,
EL (Electroluminescence), LED (Light Emittin)
g Diode), FED (Field Emission Display) and the like can be cited as examples. Among such light-emitting display devices, an organic EL device that can particularly obtain high-luminance surface light emission at a low voltage and can obtain RGB light emission with high color purity by selecting a material.
Organic EL display devices that use elements as elements have been attracting attention as display devices that enable ultra-thin, lightweight, and full-color display.

In this organic EL element, an organic layer including a light emitting functional layer is interposed between a pair of electrodes consisting of an anode to which a positive voltage is applied and a cathode to which a negative voltage is applied.
By applying a voltage between the electrodes, electrons are injected from the cathode into the organic layer and holes from the anode into the organic layer, and electron-hole recombination occurs in the organic layer, whereby light emission occurs. A conventional example of an organic EL display device including such an organic EL element will be described with reference to FIG.

The organic EL display device has a first electrode (anode) made of a transparent electrode such as ITO on one side surface of the transparent substrate 1.
2, an organic layer 3 including a light emitting functional layer made of a light emitting material such as Alq _{3 and a} second electrode (cathode) 4 made of a metal electrode such as Al
The organic EL element is formed by sequentially stacking the above. In the first electrode 2 and the second electrode 4 of this organic EL element, extraction electrodes 5A and 5B for supplying a display signal are formed.

Here, the extraction electrode 5A on the first electrode 2 side
Forms a metal extraction electrode layer 6 for lowering the wiring resistance on the transparent electrode layer 2L when forming the first electrode 2, and an insulating film 7A is formed between the extraction electrode 5A and the second electrode 4. By forming it, the short circuit is prevented. The extraction electrode 5B on the second electrode side has the metal extraction electrode layer 6 formed on the patterned transparent electrode layer 2L and the metal electrode layer 4L connected to the second electrode 4 formed thereon. An insulating film 7B is formed between the lead electrode 5B and the first electrode 2 to prevent short circuit. Since this organic EL element is significantly deteriorated when it comes into contact with the outside air, the sealing member 8 is provided to hermetically seal the vicinity of the light emitting region L of the organic EL element.

In the manufacturing process of such an organic EL display device, first, the transparent electrode layer 2L is formed on the transparent substrate 1, and then the transparent electrode layer 2L is patterned into a pattern required for display to form the first electrode 2. At the same time, the transparent electrode layer 2L forms a base of the extraction electrodes 5A and 5B. Next, Cr
After forming a metal extraction electrode layer 6 made of, for example, etc. on the transparent electrode layer 2L, this is patterned to form the extraction electrode 5
A and 5B are formed. Then, after the light emitting region L is opened to form the insulating films 7A and 7B, the organic layer 3 is formed on the exposed surface of the first electrode 2, and the organic layer 3 and the extraction electrode 5B are formed.
The second electrode 4 is formed on the organic layer 3 by forming the metal electrode layer 4L on the metal extraction electrode layer 6. Then, the sealing member 8 is covered thereon so as to cover the light emitting region L, and the sealing process is performed.

[0007]

In the extraction electrode 5B on the side of the second electrode 4 of this conventional example, the metal electrode layer 4L made of Al or the like is exposed to the outside of the sealing member 8, and the exposed metal electrode layer 4L is exposed. The metal extraction electrode layer 6 is interposed between the transparent electrode layer 2L made of ITO and the like.

The reason for adopting such a structure is that the metal electrode layer 4L made of Al or the like is directly formed on the transparent electrode layer 2L made of ITO or the like.
This is because the metal electrode layer 4L is apt to corrode when contacted with, but in such a structure of the extraction electrode 5B, the surface of the metal electrode layer 4L is exposed to the outside.
There is a problem that the exposed portion of the metal electrode layer 4L deteriorates due to the influence of heat and humidity, which hinders the supply of electricity to the second electrode 4. Further, when forming the metal electrode layer 4L forming the second electrode 4 on the extraction electrode 5B, different patterns are formed in the portion functioning as the second electrode and the portion functioning as the extraction electrode. There is another problem that two masks are required for forming and the process is complicated because different patterns are formed, resulting in high cost.

As another conventional example which copes with this, a structure as shown in FIG. 5 is adopted (the same parts as those in the above-mentioned conventional example are designated by the same reference numerals, and a duplicated explanation will be partially omitted. .). In this conventional example, the second electrode 4 is formed only on the organic layer 3 and on the connecting portion S that extends over a part of the metal extraction electrode layer 6 in the extraction electrode 5B, and the entire second electrode is inside the sealing member 8. And is hermetically sealed. That is, the extraction electrode 5B has a structure in which the metal extraction electrode layer 6 is simply formed on the transparent electrode layer 2L.

In this conventional example, the metal electrode layer 4L has a second
Since it is only necessary to form the pattern as the electrode 4, it can be formed by using a single mask, and the process can be simplified, which is advantageous in terms of cost, and the metal electrode layer 4L forming the second electrode 4 can be completely formed. Since it is sealed in, the electrode is not deteriorated and the electricity supply is not hindered.

However, the second electrode 4 and the extraction electrode 5B have a connection portion S which is a junction between different metals and has a small contact area, and the metal electrode layer 4L is formed on the extraction electrode 5B. Since a normal heat treatment step is used until that time, there is a problem that an oxide film is likely to be formed on the surface of the extraction electrode 5B and the contact resistance cannot be sufficiently reduced.

Although the organic EL display device has been described here as an example, the invention is not limited to this, and other light emitting display devices having a light emitting element as an element also have electrodes of the light emitting element and lead electrodes. The same problem occurs in the case of having a connecting portion between them.

The present invention has been proposed in order to deal with such a situation, and is composed of a light emitting element having an electrode to which a display signal is supplied, and a display signal is supplied to this electrode. In the light-emitting display device to which the extraction electrode of is connected, the organic EL display device which is one of such light-emitting display devices, and the manufacturing method thereof, the electrical resistance in the connection portion between the electrode and the extraction electrode is reduced to obtain a good signal. The challenge is to supply.

[0014]

In order to solve such a problem, the present invention has the following features.

According to a first aspect of the present invention, a first electrode formed on a transparent substrate, at least one or more light emitting functional layers formed on the first electrode, and a light emitting functional layer formed on the first electrode. A light emitting display device comprising a light emitting element having a second electrode, and connecting a lead electrode for supplying a display signal to the second electrode, wherein at least a connecting portion between the second electrode and the lead electrode is provided. It is characterized in that one or more places are fusion-bonded.

According to a second aspect of the present invention, a first electrode formed on a transparent substrate, at least one or more light emitting functional layers formed on the first electrode, and a light emitting functional layer formed on the first electrode. A light emitting display device comprising a light emitting element having a second electrode, and connecting a lead electrode for supplying a display signal to the second electrode, wherein a sealing member for covering the light emitting element is provided. Sealing the entire electrode with the sealing member, forming a connecting portion for connecting the second electrode and the extraction electrode in the sealing member, and melting and joining at least one place of the connecting portion. Characterize.

The invention according to claim 3 is based on the light emitting display device according to claims 1 and 2, and the extraction electrode is formed of a metal different from that of the second electrode.

The invention according to claim 4 is based on the light emitting display device according to claim 3, wherein the first electrode is a transparent electrode,
The second electrode is a metal electrode.

The invention according to claim 5 is based on the light emitting display device according to any one of claims 1 to 4, and is characterized in that the fusion bonding of the connection portion is performed by irradiation of laser light.

The invention according to claim 6 is based on the light emitting display device according to claims 1 to 5, wherein the light emitting element is an organic EL element.

An organic EL display device according to a seventh aspect of the present invention comprises a first electrode composed of a transparent electrode layer formed on a transparent substrate, and at least one light emitting functional layer formed on the first electrode. And an organic EL element having a second electrode formed of a metal electrode layer formed on the organic layer, and a lead-out electrode for supplying a display signal is connected to the second electrode. In an organic EL display device,
The extraction electrode comprises a metal extraction electrode layer formed on the transparent electrode layer insulated from the first electrode,
A connection part with the second electrode is formed on a part of the metal extraction electrode layer, and the second electrode and the connection part are formed in a sealing member to hermetically seal the connection part. It is characterized in that a melted joint portion is formed by laser light irradiation at at least one place.

According to an eighth aspect of the present invention, there is provided a method of manufacturing an organic EL display device, which comprises a step of forming a transparent electrode layer having a required pattern on a transparent substrate, and a step of patterning the transparent electrode layer to form a first electrode. A step of forming a metal extraction electrode layer on the transparent electrode layer or the transparent substrate; a step of forming an organic layer including at least one light emitting functional layer on the exposed surface of the first electrode; Second on exposed surface of layer
The method includes a step of forming an electrode and a metal electrode layer forming a connection portion on the metal extraction electrode layer, and a sealing step of sealing at least the entire metal electrode layer with a sealing member. Before or after the stopping step, the metal extraction electrode layer and the metal electrode layer in the connection portion are melt-bonded by irradiation of laser light.

The present invention having such characteristics has the following functions.

According to the light emitting display device of each claim, since the connection portion of the electrode to which the display signal is supplied in the light emitting element and the extraction electrode are fusion-bonded, even when there is a problem in the contact state of the connection portion during formation. Since the melt-bonding is performed thereafter, the electrical connection of the connection portion is surely performed and the electrical resistance can be reduced. Thereby, it is possible to favorably supply the signal to the light emitting element.

In the light emitting display device according to the second aspect, a sealing member for covering the light emitting element is provided, the entire second electrode is sealed with this sealing member, and the connecting portion is formed in the sealing member. Therefore, the deterioration of the second electrode and the connection portion can be prevented, and the electric resistance of the connection portion can be further reduced. Further, since the second electrode may be formed on the light emitting functional layer and the connecting portion of the extraction electrode, it is only necessary to form a single mask pattern and the process can be simplified, so that the cost can be reduced.

Further, in the light emitting display device according to claims 3 and 4,
Since the extraction electrode is formed of a metal electrode different from the second electrode, the extraction electrode may be interposed between the transparent electrode layer (first electrode layer) and the second electrode layer to form a buffer layer. it can. As a result, even when the second electrode is formed on the transparent electrode layer, the transparent electrode layer and the second electrode do not come into direct contact with each other, and the corrosion or deterioration of the second electrode due to this direct contact is prevented. You can

Further, in the present invention, the connecting portion between the second electrode and the extraction electrode is a connection between different kinds of metals, but since this connecting portion is fusion-bonded, even if the connection between different kinds of metal is made, the electrical resistance is high. Can be reduced. Thus, when patterning the transparent electrode layer, a layer of the extraction electrode can be formed on the transparent electrode layer while leaving a part of the layer, and a connection portion with the second electrode can be formed thereon.
The electrode patterning process can be simplified.

In the light-emitting display device according to the fifth aspect of the present invention, the fusion-bonding of the connection portion is performed by irradiating the laser beam, so that the spot-shaped fusion-bonding portion can be formed with respect to the connection portion. Even in the portion, the electric resistance can be surely reduced.

Even when the connecting portion is formed in the sealing member, the connecting portion can be irradiated with the laser beam through the transparent substrate after the sealing member is used for sealing. It is possible to perform the fusion bonding of the connection portion without changing the intermediate stage of the manufacturing process. When the sealing member is a transparent member such as glass, it is possible to irradiate the connecting portion with laser light through the sealing member.
Further, even when the extraction electrode is made of a metal different from that of the second electrode, the connection portion between different kinds of metals is melted and synthesized by the irradiation of the laser beam, so that the electric resistance of the connection portion is surely lowered. be able to.

In the light-emitting display device according to the sixth aspect, since the above-mentioned characteristics can be applied to the organic EL element, the second electrode not directly formed on the transparent substrate is surely connected to the extraction electrode and has low resistance. Withdrawal becomes possible. Also, the second
When the electrode and the connecting portion are sealed with a sealing member, electricity can be reliably supplied to the second electrode without deterioration of the electrode, and the light emitting functional layer of the organic EL is shielded from the outside air. Therefore, the life of the light emitting display device can be extended.

In the organic EL display device and the manufacturing method thereof according to claims 7 and 8, since the metal lead electrode layer connected to the second electrode is formed on the transparent electrode layer formed on the transparent substrate, The metal extraction electrode layer can be formed on a part of the transparent electrode layer, and the patterning of the transparent electrode layer can be simplified. In addition, since the connection portion is formed on the metal extraction electrode layer in the second electrode composed of the metal electrode layer, there is no possibility that the metal electrode layer and the transparent electrode layer are in direct contact with each other to cause corrosion of the electrode. Further, since the metal electrode layer including the connecting portion is formed in the sealing member and hermetically sealed, there is no fear of deterioration of the metal electrode layer, and the electricity is reliably supplied to the second electrode. be able to. Further, since the metal electrode layer may be formed on the organic layer forming the second electrode and a part of the metal extraction electrode layer, it is only necessary to form a single mask pattern for forming the second electrode, which simplifies the forming process. The cost can be reduced as well.

At the connection portion, the metal electrode layer and the metal extraction electrode layer made of a different kind of metal are connected. However, since a fusion joint is formed by laser light irradiation at this connection portion, a connection between different kinds of metal is made. Even if there is a problem with the adhesion at the time of formation, a connection with low electric resistance can be obtained. Further, since the fusion bonding process by laser light irradiation can be performed after the sealing step by the sealing member by irradiating the connecting portion with laser light through the transparent substrate or the transparent sealing member, the organic EL Necessary processing can be performed without changing the steps in the manufacturing process of the display device.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings (the same parts as those in the prior art will be designated by the same reference numerals and the description thereof will be partially omitted). In the following embodiments, an organic EL display device will be described as an example, but the present invention can also be applied to another light emitting display device having a structure of an electrode and a lead electrode in a similar light emitting element.

FIG. 1 shows an organic EL according to one embodiment of the present invention.
It is explanatory drawing which shows a display device. The organic EL display device includes, on one side surface of a transparent substrate 1 made of glass or the like, a first electrode (anode) 2 made of a transparent electrode layer 2L made of ITO or the like, and light emission of at least one layer made of a luminescent material such as Alq _3. An organic EL element in which a functional layer-containing organic layer 3 and a second electrode (cathode) 4 composed of a metal electrode layer such as Al are sequentially laminated. In the first electrode 2 and the second electrode 4 of this organic EL element, Is an extraction electrode 5A for supplying a display signal,
5B is formed.

Here, the extraction electrode 5A on the first electrode 2 side
Forms a metal extraction electrode layer 6 to serve as a barrier layer on the transparent electrode layer 2L when forming the first electrode 2, and an insulating film 7A is formed between the extraction electrode 5A and the second electrode 4. Therefore, the lead electrode 5B on the second electrode side is formed with a metal lead electrode layer 6 serving as a barrier layer on a part of the patterned transparent electrode layer 2L to prevent a short circuit. An insulating film 7B is formed between the first and second electrodes to prevent short circuit.

The material of the metal extraction electrode layer 6 is a conductive metal material different from the metal electrode layer 4L or the transparent electrode layer 2L forming the second electrode 4, and a material such as Cr is used. The entire 4L is sealed with a sealing member 8 made of metal or glass, and a connecting portion S between the metal extraction electrode layer 6 and the metal electrode layer 4L is formed in the sealing member 8. Then, the connecting portion S is irradiated with the laser beam La through the transparent substrate 1 to form a spot-shaped fusion-bonded portion 9a.
Is formed in at least one place and a plurality of places as required. When the sealing member 8 is formed of a transparent member such as glass, the fusion-bonded portion 9a can also be formed by irradiating the laser beam La'through the sealing member 8.

According to the organic EL display device of such an embodiment, since the metal extraction electrode layer 6 and the metal electrode layer 4L of different metals are melt-bonded at the connection portion S by local heating with laser light, It becomes possible to reduce the electric resistance at the connection portion S. Further, since the entire metal electrode layer 4L including the connecting portion S is sealed by the sealing member 8, the metal electrode layer 4L forming the second electrode 4 is formed.
Does not deteriorate when exposed to heat or moisture. This makes it possible to satisfactorily supply electricity to the second electrode.

A method of manufacturing the organic EL display device according to this embodiment will be described. In the first step, the transparent electrode layer 2L is formed on the transparent substrate 1, and patterning required for display is performed to form the first electrode 2. At this time, the patterning process can be simplified by minimizing the patterning and leaving the transparent electrode layer 2L as a base of the extraction electrodes 5A and 5B.

As the next step, the extraction electrodes 5A, 5B
A metal lead electrode layer 6 is formed on the upper surface, and subsequently, the light emitting region L is masked to form insulating films 7A and 7B in necessary regions. Then, after the organic layer 3 is formed on the exposed surface of the first electrode 2 by vapor deposition or the like, the metal electrode layer 4L to be the second electrode 4 is formed on the connection portion S between the organic layer 3 and the metal extraction electrode layer 6. To form.

Then, after a sealing step of providing the sealing member 8 covering the entire metal electrode layer 4L, the fusion bonding portion 9a is formed by irradiation with the laser beam La or La '. A light source used in this laser light irradiation is a laser such as a YAG laser that can obtain a desired output, and the output light is condensed in a spot shape by an optical system and is transmitted through the transparent substrate 1 or the transparent sealing member 8. Irradiate the connection part.

According to such a manufacturing method, even when the transparent electrode layer 2L is left as a base of the extraction electrode 5B,
Since the metal extraction electrode 6 does not directly contact the transparent electrode layer 2L and the second electrode 4 with each other, the corrosion of the electrode does not occur. In addition, since the formation of the fusion-bonded portion 9a by laser light irradiation is performed after the sealing step is completed, it is not necessary to change the series of manufacturing steps of the organic EL display device.

FIG. 2 is an explanatory view showing another embodiment of the present invention. The same parts as those in the above-described embodiment are designated by the same reference numerals, and a duplicate description will be partially omitted. In this embodiment, the fusion-bonded portion 9b formed in the connection portion S is a spot hole formed by laser light irradiation. This also allows the metal extraction electrode layer 6 and the metal electrode layer 4L to be formed on the inner surface of the spot hole.
Since the fusion-bonded portion is formed, it is possible to obtain the same effect as that of the above-described embodiment. Further, the manufacturing method can be performed in the same steps as those in the above-described embodiment.

FIG. 3 is an explanatory view showing another embodiment of the present invention. The same parts as those in the above-described embodiment are designated by the same reference numerals, and a duplicate description will be partially omitted. In this embodiment, when patterning the transparent electrode layer 2L, the extraction electrode 5
The base layer in B is removed. According to this, the extraction electrode 5B on the second electrode 4 side is formed only by the metal extraction electrode layer 6 made of Cr or the like, and the metal electrode layer 4L forming the second electrode 4 at the connection portion S in the sealing member 8. Connected with. Also in this embodiment, by forming the fusion-bonded portion 9b at the connection portion S in the sealing member 8, the same operation as that of the above-described embodiment is achieved. Also, the manufacturing method of this embodiment can be performed in the same steps as those of the above-described embodiments except for the patterning of the transparent electrode layer 2L.

1 to 5 show a light emitting display device having a single light emitting region L for easy understanding of the invention, the light emitting display device of the present invention has such a structure. The shape is not limited, and a light emitting display device in which a plurality of light emitting regions L are arranged in a dot matrix can be targeted.

[0045]

Since the present invention is constructed in this way,
Consisting of a light-emitting element having an electrode to which a display signal is supplied,
A light emitting display device in which a lead electrode for supplying a display signal to the electrode is connected, an organic EL display device which is one of such light emitting display devices, and a method of manufacturing the same, the connection between the electrode and the lead electrode Good electrical signal supply can be achieved by reducing the electric resistance in the portion.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an organic EL display device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing another embodiment of the present invention.

FIG. 3 is an explanatory diagram showing another embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a conventional organic EL display device.

FIG. 5 is an explanatory diagram showing a conventional organic EL display device.

[Explanation of symbols]

1 transparent substrate 2 First electrode 3 organic layers 4 Second electrode 5A, 5B extraction electrode 6 Metal extraction electrode layer 7A, 7B insulating film 8 Sealing member 9a, 9b fused joint L luminous area S connection part

Claims (8)

[Claims] 1. A first electrode formed on a transparent substrate, at least one light-emitting functional layer formed on the first electrode, and a second electrode formed on the light-emitting functional layer. A light-emitting display device having a lead-out electrode for supplying a display signal to the second electrode, wherein at least one or more connecting portions of the second electrode and the lead-out electrode are melt-bonded to each other. A light emitting display device characterized by the above. 2. A first electrode formed on a transparent substrate, at least one or more light emitting functional layers formed on the first electrode, and a second electrode formed on the light emitting functional layer. A light emitting display device in which a lead electrode for supplying a display signal to the second electrode is connected, a sealing member covering the light emitting element is provided, and the entire second electrode is sealed. A light-emitting display device characterized in that a connection part for connecting the second electrode and the extraction electrode is formed in the sealing member while being sealed with a member, and at least one or more of the connection parts are melt-bonded. . 3. The lead electrode is formed of a metal different from that of the second electrode.
The light emitting display device according to. 4. The light emitting display device according to claim 3, wherein the first electrode is a transparent electrode and the second electrode is a metal electrode. 5. The light emitting display device according to claim 1, wherein fusion bonding of the connection portion is performed by irradiation with laser light. 6. The light emitting display device according to claim 1, wherein the light emitting element is an organic EL element. 7. A first electrode formed of a transparent electrode layer formed on a transparent substrate, an organic layer formed of at least one light-emitting functional layer formed on the first electrode, and formed on the organic layer. An organic EL display device having an extraction electrode for supplying a display signal to the second electrode, the extraction electrode comprising: A metal extraction electrode layer formed on the transparent electrode layer insulated from the first electrode,
A connection part with the second electrode is formed on a part of the metal extraction electrode layer, and the second electrode and the connection part are formed in a sealing member to hermetically seal the connection part. An organic EL display device, characterized in that a fusion-bonded portion is formed by laser irradiation at at least one location. 8. A step of forming a transparent electrode layer having a required pattern on a transparent substrate, a step of patterning the transparent electrode layer to form a first electrode, and a metal extraction electrode on the transparent electrode layer or the transparent substrate. Forming a layer, and the first
Forming an organic layer including at least one light emitting functional layer on the exposed surface of the electrode; forming a second electrode on the exposed surface of the organic layer; and forming a connection portion on the metal extraction electrode layer And a sealing step of sealing at least the entire metal electrode layer with a sealing member, and before or after the sealing step, a metal lead electrode layer in the connection portion. A method for manufacturing an organic EL display device, characterized in that the metal electrode layer and the metal electrode layer are melt-bonded by irradiation with laser light.