JP2003272832A - Organic el element, and manufacturing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL element of which, generation of a residual of the electrode forming material formed to a display area, is properly prevented at low cost. <P>SOLUTION: For the organic EL element S1, a laminate 5, formed by successively laminating a positive electrode 2, an organic layer including a light emitting layer made of organic EL material, and a negative electrode 4, is formed on a substrate 1. A positive electrode terminal 2a for connecting the positive terminal 2 to an external circuit, and a negative electrode terminal 2b for connecting the negative terminal 4 to the external circuit, are formed to part of the substrate 1 where the laminate 5 is not formed. The positive electrode terminal 2a and the negative electrode terminal 2b are made of a sintered compact formed by sintering an organic metal compound. <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 an organic EL (electro-luminescent) device in which a lower electrode, an organic layer and an upper electrode are sequentially laminated on a substrate and a terminal portion for connecting each electrode to an external circuit is formed. TECHNICAL FIELD The present invention relates to a luminescence device and a manufacturing method thereof.

[0002]

2. Description of the Related Art In this type of organic EL element, a laminated body is formed by sequentially laminating a lower electrode, an organic layer including a light emitting layer made of an organic EL material, and an upper electrode on a substrate. In the non-formed portion of the laminated body, a lower electrode terminal portion for connecting the lower electrode to the external circuit and an upper electrode terminal portion for connecting the upper electrode to the external circuit are formed. Is.

In such an organic EL device, a transparent conductive film of indium and tin oxide, that is, a film of ITO is generally used as a lower electrode. Then, this ITO film is formed on the substrate and patterned to form the lower electrode and the above-mentioned electrode terminal portions. Then, an organic EL element is manufactured by forming a film of the organic layer and the upper electrode by vacuum vapor deposition or the like.

In such an organic EL element, an electric field is applied between the lower electrode and the upper electrode from an external circuit via each terminal portion so that the light emitting layer in the laminate as a pixel emits light. It has become.

[0005]

By the way, the ITO described above is used.
Resistivity is as high as about e.g. 1.4 × 10- ⁸ Ω · cm of. Therefore, the necessary current is not applied to each pixel, and the luminance is particularly insufficient in a pixel having a long wiring length, that is, a pixel far from the terminal portion, and the display quality is degraded.

Therefore, conventionally, in the terminal portion of each electrode, a film made of Cr or the like is formed on the substrate on ITO,
By patterning this using a photolithographic technique, an auxiliary wiring made of Cr or the like is formed to reduce the wiring resistance of the terminal portion.

However, in the formation of this auxiliary wiring, the film formation of Cr or the like and the photolithographic technique require expensive equipment and expensive processing costs. Further, since the film of Cr or the like is formed over the entire area of the substrate and then patterned, a residue of Cr may remain in the display region due to a photo defect due to a foreign substance or the like. The presence of such a residue in the display region causes a short circuit between the electrodes, which causes a defect such as a non-lighted pixel.

To solve the problem of residues in the display area, Japanese Patent Laid-Open No. 2001-185363 discloses that the display area where film formation is not required is covered with a resist material in advance, and the auxiliary wiring such as Cr is formed. At the time of film formation, the display area is protected by the resist material so that the residue is not left in the display area.

However, such a method requires steps such as formation of a resist material and subsequent peeling of the resist material, which is troublesome.
As a result, the cost is increased.

Therefore, in view of the above problems, the present invention is an organic EL device in which a lower electrode, an organic layer, and an upper electrode are sequentially laminated on a substrate and a terminal portion for connecting each electrode to an external circuit is formed. It is an object of the present invention to appropriately prevent the residue of the forming material of the terminal portion in the display region from remaining in the element at low cost.

[0011]

In order to achieve the above object, the present inventors first mixed silver particles with a binder as a method for producing the terminal portion at a low cost without leaving the above residue in the display area. A method of forming a terminal portion by screen printing a silver paste was examined. However, it was found that this method causes the following problems.

Usually, in an organic EL element, by covering the element substrate on which the element is formed with a sealing substrate such as metal or glass to protect the element, an organic film is formed by moisture in the air. It is designed to prevent deterioration.

In this case, the terminal portion needs to be exposed to the outside from the sealing substrate, and the sealing substrate forms a sealing material on the terminal portion and on the element substrate between the terminal portions, and the sealing material is interposed therebetween. To be bonded to the element substrate. here,
The thickness of the sealing material is usually designed to be 20 μm or less in consideration of the permeation amount of moisture from the outside air.

However, since the wiring thickness of the terminal portion made of silver paste is as thick as, for example, about 10 μm, the thickness of the sealing material arranged on the element substrate where there is no terminal portion, that is, between the terminal portions, is considerably thick. Therefore, due to the flow of the sealing material in this portion, sufficient adhesion between the element substrate and the sealing substrate cannot be obtained, moisture enters from this portion, the organic layer deteriorates, and light emission stops. The problem arises.

Therefore, the inventors of the present invention have made earnest studies in consideration of the fact that the wiring thickness of the terminal portion is likely to be large in the method using the silver paste, so that a thinner wiring thickness is possible. As a result, the present invention has been created.

That is, in the invention described in claims 1 to 3, the lower electrode (2), the organic layer (3) including the light emitting layer (3b) made of an organic EL material, and the upper part are provided on the substrate (1). A laminated body formed by sequentially laminating electrodes (4) is formed,
On the non-formed portion of the laminated body on the substrate, a lower electrode terminal portion (2a) for connecting the lower electrode to an external circuit and an upper electrode terminal portion (2b) for connecting the upper electrode to the external circuit. In the organic EL element in which is formed, at least one of the lower electrode terminal portion and the upper electrode terminal portion is made of a sintered body obtained by sintering an organic metal compound. And

According to this, after the organometallic compound is placed on the substrate (1) by a screen printing method or a dispense coating method, the terminal portion (2a, 2b) as a sintered body is easily formed by curing the organometallic compound. can do. Therefore, it is possible to appropriately prevent the residue of the material forming the terminal portion in the display area from remaining at a low cost.

Further, when the organometallic compound is sintered, the organic component in the compound is discharged as a decomposition gas during the sintering to form a terminal portion as a sintered body.
The terminal portions (2a, 2b) having a thinner wiring thickness and a sufficient wiring resistance can be obtained as compared with the method using the above silver paste.

The reference numerals in parentheses for each means described above are examples showing the correspondence with specific means described in the embodiments described later.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention shown in the drawings will be described. FIG. 1 is a schematic plan view of an organic EL element S1 according to an embodiment of the present invention, and FIG. 2 is A in FIG.
FIG. 3 is a schematic cross-sectional view taken along line A, and FIG. 3 shows B- in FIG.
It is a schematic sectional drawing along the B line. Note that, in FIG. 1, various hatchings are provided for the sake of convenience for easy identification, but these are not cross sections.

The organic EL element S1 comprises a substrate 1 made of a transparent glass substrate, a resin substrate or the like, and an organic material including an anode 2 as a lower electrode and a light emitting layer 3b made of an organic EL material on the substrate 1. A layered product (organic EL layer) 5 is formed by sequentially layering the layer 3 and the cathode 4 as the upper electrode.

The arrangement of the laminate 5 in this embodiment is as follows. A plurality of anodes 2 and a plurality of cathodes 4 are provided, and the plurality of anodes 2 and the plurality of cathodes 4 are arranged in stripes extending in directions orthogonal to each other (see FIG. 1). The organic layer 3 sandwiched between the electrodes 2 and 4 is patterned in the same stripe shape as the cathode 4.

The portion of the laminated body 5 where the anode 2 and the cathode 4 intersect and overlap each other forms a pixel as a light emitting portion. In this example, as shown in FIG. 1, the central portion of the substrate 1 is formed. To the periphery, a plurality of pixels (laminated body 5) are arranged in a grid pattern.

The display area is a region on the substrate 1 where a plurality of pixels (laminated body 5) are formed.
Here, as shown in FIGS. 2 and 3, a pixel separation layer 6 made of an electrically insulating insulating film is formed between the stripes of the anode 2 and between the stripes of the organic layer 3 and the cathode 4. .

A plurality of partition layers 7 are formed in stripes on the portion of the pixel separation layer 6 located between the stripes of the organic layer 3 and the cathode 4. As a result, each pixel, that is, the stacked body 5 is partitioned and separated by the grid-shaped pixel separation layer 6 and the partition wall layer 7 formed along the stripe direction of the cathode 4.

Here, the materials of the layers 2 to 7 formed on the substrate 1 will be described. First, the anode 2 is a transparent electrode film made of ITO (oxide of indium and tin) or the like, which is formed by a sputtering method or the like and patterned by using a photolithographic technique.

The organic layer 3 is formed by a vacuum vapor deposition method. The hole transporting layer 3a made of a hole transporting organic material, the hole transporting organic material, and the electron are sequentially formed from the anode 2 side. A light emitting layer 3b made of an organic EL material obtained by doping a transporting organic material with a fluorescent dye, and an electron transporting layer 3c made of an electron transporting organic material are laminated.

The cathode 4 is made of a metal material such as Al vapor-deposited. Further, the pixel separation layer 6 is made of an electrically insulating resin material such as photosensitive polyimide, and the partition layer 7
Is made of a negative photosensitive resin resist material or the like.

Further, in the peripheral portion of the display area on the substrate 1, that is, in the non-formation portion of the plurality of pixels (the laminated body 5),
An anode terminal 2a electrically connected to the anode 2 and a cathode terminal 2b electrically connected to the cathode 4 are formed in a stripe shape corresponding to the anode 2 and the cathode 4.

These terminal portions 2a and 2b are for connecting the anode 2 and the cathode 4 to an external circuit (not shown), and the anode terminal 2a is a lower electrode terminal portion and a cathode terminal 2.
b is configured as an upper electrode terminal portion. For example,
The terminal portions 2a and 2b and the external circuit are electrically connected to each other using a technique such as anisotropic conductive adhesive tape or wire bonding.

In this example, the anode terminal 2a is laminated on the anode 2 extended to the peripheral portion on the substrate 1, and the cathode terminal 2b is on the substrate 1 on substantially the same plane as the anode 2. Has been formed. These terminal portions 2a and 2b are made of silver,
The sintered body is formed by sintering an organometallic compound such as an organometallic complex containing gold or copper.

For example, the organometallic compound is prepared from a mixture of a fatty acid silver-amine coordination structure with an organic acid. Specifically, 35% of fatty acid silver
45%, dihydroterpineol 10% to 20%, 1,
2-diaminocyclohexane 10% to 20%, cyclohexanecarboxylic acid 10% to 20%, acetic acid 1% to 10%,
It is composed of 1% to 5% phthalic anhydride. Fatty acid silver is represented by R-COOAg, and R is composed of an alkyl group, and examples thereof include a methyl group, an ethyl group and a propyl group.

Then, the organometallic compound is selectively applied to a predetermined portion of the substrate 1 by a screen printing method or a dispense coating method and cured (baked), so that the organic component in the organometallic compound becomes a decomposition gas. Is discharged and becomes a sintered body in which metal is deposited.

Although not shown, in the organic EL element S1, by covering the substrate 1 with a sealing substrate made of metal, glass, or the like, the organic layer 3 in the element S1 can be removed by moisture in the atmosphere. It is designed to prevent deterioration. In this case, a sealing material is formed on the terminal portions 2a and 2b and the substrate 1 between the terminal portions 2a and 2b, and the substrate 1 and the sealing substrate are bonded to each other via the sealing material.

Next, a method of manufacturing the above-mentioned organic EL element S1 will be described with reference to specific examples. FIG. 4 is a diagram showing a manufacturing process flow of the present manufacturing method. First, the anode 2 is formed at a predetermined position on the substrate 1 made of a glass substrate (anode forming step). In this example, the anode 2 is formed by forming a film of ITO by a sputtering method or the like and patterning it by a normal photolithography method.

Next, the substrate 1 is formed in the portion between the pixels.
The pixel separation layer 6 is formed on the anode and the anode 2 (pixel separation layer forming step). In this example, a resin (resist) such as photosensitive polyimide is spin-coated to form a film on the entire surface of the substrate 1. After baking the film, the pixel separation layer 6 is formed by exposing and developing.

Further, a partition layer 7 for dividing the organic layer 3 and the cathode 4 is formed on the pixel separating layer 6 by a photolithography method (partition layer forming step). In this example, a negative photosensitive resin resist that will be the partition layer 7 is spin-coated on the entire surface of the substrate 1, baked, and then exposed and developed to form the partition layer 7.

Next, the terminal portions 2a and 2b are formed. First, a wiring material made of an organometallic compound is printed on a predetermined portion of the substrate 1 by a screen printing method (terminal portion wiring material forming step). The thickness of the printed wiring material was about 10 μm. In this example, as the organometallic compound, a product name XE102-25 manufactured by NAMICS CO., LTD. Was used as an organometallic compound prepared by mixing an organic acid with the coordination structure of the above-described fatty acid silver and amine.

Subsequently, the substrate 1 on which the wiring material is printed is set to 1
After drying at 50 ° C. for 10 minutes, baking is performed at 280 ° C. for 60 minutes (terminal portion wiring material baking step). By these drying and firing steps, the coordination compound of the wiring material is decomposed and silver is deposited. Also,
By discharging amine and organic acid as decomposition gas, the film thickness of the wiring material after firing, that is, the terminal portions 2a and 2b becomes 1 μm or less, which is 1/10 or less of the film thickness (10 μm) immediately after printing, and the ratio thereof resistance value became 8 × 10- ⁶ Ω · cm.

After that, the substrate 1 is washed (substrate washing step), the organic layer 3 is formed on the anode 2 by a vacuum deposition method or the like and laminated (organic layer forming step), and the organic layer 3 is placed on the organic layer 3. Then, the cathode 4 is formed into a film by a vacuum deposition method or the like and laminated (cathode film forming step).

As a result, the partition layer 7 is formed on the substrate 1.
The organic layer 3 and the cathode 4 are laminated in stripes on the anode 2 and the substrate 1 which are located between. In this way, the laminated body 5 that constitutes the above-mentioned lattice-shaped pixel is formed.
Although not shown in FIGS. 1 to 3, in practice, a film similar to the organic layer 3 and the cathode 4 is laminated on the upper end surface of the partition layer 7 by such a film forming method.

Further, a sealing substrate is prepared in which engraving is formed and a moisture absorbent is held inside the engraving, and the terminal portion 2
The substrate 1 and the sealing substrate are bonded to each other via an adhesive (sealing material) on the substrates a and 2b and between the terminals 2a and 2b. In addition, in order to control the thickness of the adhesive to be constant, an adhesive mixed with resin beads having a diameter of 6 μm was used. In this way, the organic EL element S1 is manufactured.

By the way, according to this embodiment, the anode terminal 2a and the cathode terminal 2b are made of a sintered body obtained by sintering an organometallic compound. According to this, as shown in the above-mentioned manufacturing method, after the organometallic compound is arranged on the substrate 1 by the screen printing method, it is cured to easily form the terminal portions 2a, 2b as the sintered body. You can

Therefore, the patterning using the photolithographic technique or the like, which is necessary for the film formation of the conventional terminal portion, and the resist material for preventing the residual residue are unnecessary. Therefore,
According to the present embodiment, it is possible to appropriately prevent the residual residue of the forming material of the terminal portions 2a and 2b in the display area at low cost.

Further, by sintering the organometallic compound, the organic components in the compound are discharged as a decomposition gas at the time of sintering and the terminal portions 2a, 2b as the sintered body are formed. As compared with the method using the silver paste, the terminal portion having a thinner wiring thickness and a sufficient wiring resistance can be obtained.

(Other Embodiments) The anode terminal 2a is
It does not have to be a sintered body laminated on the anode 2 extended to the peripheral portion on the substrate 1. For example, the anode terminal 2a may be a sintered body formed on the same plane as the anode 2 in the peripheral portion of the substrate 1, and the extended anode 2 may be connected to this sintered body.

Further, either one of the anode terminal 2a and the cathode terminal 2b may be made of a sintered body obtained by sintering an organometallic compound. For example, the anode terminal 2a may be the anode 2 itself extended to the peripheral portion on the substrate 1.

The placement of the organometallic compound on the substrate 1 may be performed by a dispense coating method other than the screen printing method.

[Brief description of drawings]

FIG. 1 is a schematic plan view of an organic EL element according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view taken along the line AA in FIG.

3 is a schematic cross-sectional view taken along the line BB in FIG.

FIG. 4 is a diagram showing a process flow of a method for manufacturing an organic EL device according to the above embodiment.

[Explanation of symbols]

1 ... Substrate, 2 ... Anode, 2a ... Anode terminal, 2b ... Cathode terminal, 3 ... Organic layer, 3b ... Light emitting layer, 4 ... Cathode.

Claims (3)

[Claims] 1. A lower electrode (2), an organic layer (3) including a light emitting layer (3b) made of an organic EL material, on a substrate (1),
A laminated body formed by sequentially laminating upper electrodes (4) is formed, and a lower electrode terminal portion for connecting the lower electrode to an external circuit is formed on a portion of the substrate where the laminated body is not formed. (2
a) and an upper electrode terminal portion (2b) for connecting the upper electrode to an external circuit are formed, wherein at least one of the lower electrode terminal portion and the upper electrode terminal portion is formed. The organic EL element is characterized in that the terminal portion is made of a sintered body obtained by sintering an organometallic compound. 2. The method for manufacturing an organic EL device according to claim 1, wherein the organometallic compound is placed on the substrate (1) by a screen printing method and then cured to form the sintered body. A method for manufacturing an organic EL device, comprising: 3. The method for manufacturing an organic EL device according to claim 1, wherein the organometallic compound is arranged on the substrate (1) by a dispense coating method and then cured to form the sintered body. A method for manufacturing an organic EL device, comprising: