JP2002117972A - Organic el display device and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic EL(electroluminescent) display device preventing steam from infiltrating into the inner space from a connecting portion of a sealing member and a transparent substrate. SOLUTION: This organic EL display device 1 is provided with a transparent substrate 6, an organic element 17 formed on the transparent substrate 6, with its extracting electrodes 14 and 15 formed on the transparent substrate 6, the sealing member 19 coated and arranged on the organic EL element 17, an insulating layer 29 formed over the sealing region on the transparent substrate 6 sealed with the sealing member 19, covering the portion crossing the sealing region of the extracting electrodes 14 and 15 in an insulated state, and made of a moisture-nonpermeable material, and a low-melting point metal layer 31 provided between the lower face of the peripheral edge section of the sealing member 19 and the upper face of the insulating layer 29 to stick and fix the sealing member 19 and the insulating layer 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic EL display device used for various displays, wherein a non-light emitting portion (dark spot) is formed on an organic EL element by water vapor or oxygen in the air.
TECHNICAL FIELD The present invention relates to an organic EL display device capable of preventing occurrence and expansion of an image and a method of manufacturing the same.

[0002]

2. Description of the Related Art Generally, an organic EL device has at least one element.
A thin film layer composed of at least one organic layer is formed as a thin film element by sandwiching at least one from both sides thereof with a transparent electrode layer. This organic EL element has the advantage of being capable of realizing a high-contrast display in a self-luminous type. However, there is a disadvantage that a non-light-emitting portion (dark spot) is generated and further enlarged. This is thought to be because the electrode layer (back electrode layer) deposited on the organic layer has defects such as pinholes, and oxygen and water enter the organic layer through the pinholes. Therefore, it is necessary to seal the organic EL element in order to prevent such a situation.

In order to solve this sealing problem, a conventional organic EL display device 100 is, as shown in FIG.
A transparent electrode layer 8, an organic layer 10, and a back electrode layer 12 are sequentially laminated on the transparent electrode layer 8, and an extraction electrode 14, 15 is formed on the transparent substrate 6 from each of the transparent electrode layer 8 and the back electrode layer 12 by pattern formation. An EL element 17 is formed. In this state, the extraction electrodes 14 and 15 are exposed to
An encapsulating member 19 is hermetically adhered and fixed to the transparent substrate 6 with an adhesive 27 made of an organic material so as to cover the L element 17.

[0004] The organic EL display device 1 configured as described above.
In the case of 00, water vapor permeates the internal space little by little through the adhesive 27 made of an organic material, and as a result, a dark spot may be enlarged after a long time,
A moisture absorbent 21 such as silica gel or barium oxide is fixed on the inner surface side of the sealing member 19 with a film 23 and sealed in the internal space, and the moisture absorbent 21 penetrates the adhesive 27 and absorbs water vapor that has entered the internal space. I was trying to make it.

[0005]

However, in the organic EL display device 100, since the penetration of the water vapor into the internal space through the layer of the adhesive 27 is not fundamentally prevented, the organic EL display device 100 is completely dark. I could not suppress the spot expansion.

An object of the present invention is to provide an organic EL display device in which water vapor is prevented from entering an internal space through a joint between a sealing member and a transparent substrate.

[0007]

According to a first aspect of the present invention, there is provided a transparent substrate, and an electrode formed on the transparent substrate and having an extraction electrode formed on the transparent substrate. The formed organic EL element and the organic E
A sealing member covered and arranged on the L element, and a portion formed at least along the bonding region on the transparent substrate to which the sealing member is bonded and crossing the bonding region of the extraction electrode in an insulating state. An insulating layer made of a non-moisture-permeable material to be coated, and interposed between the lower surface of the peripheral portion of the sealing member and the upper surface of the transparent substrate so as to cross over the extraction electrode via the insulating layer. A metal bonding layer for bonding a sealing member on the transparent substrate.

According to a second aspect of the present invention, the metal bonding layer is formed of a metal such as indium, gallium, or lead, or an alloy such as an aluminum-germanium alloy or a gallium-indium alloy.

[0009] The invention described in claim 3 is based on claim 1.
Or a manufacturing method for manufacturing an organic EL display device according to claim 2, wherein a first step of pattern-forming the transparent electrode layer forming the extraction electrode and the organic EL element on the transparent substrate; A second step of forming the insulating layer so as to cover at least a portion of the extraction electrode crossing the bonding region along the bonding region on the transparent substrate in an insulating manner; and forming the insulating layer on the transparent substrate. A third step of forming a remaining layer constituting the organic EL element on the transparent electrode layer, and a lower surface of a peripheral portion of the sealing member on the transparent substrate via the insulating layer by the metal bonding layer. And a fourth step of bonding.

Further, in the invention according to claim 4, the insulating layer is formed of a glass material, and the third step is performed after the second step.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an organic EL display according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic cross-sectional view of an organic EL display device according to this embodiment, and FIGS. 2 and 3 are diagrams illustrating manufacturing steps of the organic EL display device according to this embodiment.

As shown in FIG. 1, an organic EL display device 1 according to this embodiment includes a transparent substrate 6 formed of a glass material or a resin material, and an organic EL element 17 formed on the transparent substrate 6. An insulating layer 29 formed on a sealing region (joining region) around the organic EL element 17;
A sealing member 19 formed of a glass material or a metal material covered on the element 17, and interposed between the lower surface of the peripheral portion of the sealing member 19 and the upper surface of the insulating layer 29 to insulate the sealing member 19; A low melting point metal layer (metal bonding layer) 31 for bonding and fixing (joining) to the layer 29, and the sealing member 19 is placed on the transparent substrate 6 by the insulating layer 29 and the low melting point metal layer 31 functioning as a sealing layer. It is configured to be hermetically sealed.

The organic EL element 17 has a transparent electrode layer 8 made of, for example, ITO, an insulating film 9 defining a display pattern, an organic layer 10, and a back electrode layer 12 made of, for example, an aluminum material. Along with being laminated,
The extraction electrodes 14 and 15 are formed by patterning on the transparent substrate 6 so as to be extracted outward from the electrode layers 8 and 12 respectively.

The organic layer 10 is not shown, for example,
In order from the transparent electrode layer 8 side, a hole injection layer made of copper phthalocyanine or the like, a hole transport layer made of α-NPD or the like, an electron transporting light emitting layer formed by adding dimethylquinacridone to an aluminum quinoline complex (Alq3), and lithium fluoride And the like are stacked.

The insulating layer 29 is made of an insulating and non-moisture-permeable inorganic material such as a glass material.
15 is formed so as to cover a portion crossing a sealing region (a region on the transparent substrate 6 to which the sealing member 19 is sealed) in an insulating state. As a result, the insulating layer 29 prevents the permeation of the extraction electrode 14, while preventing the penetration of water vapor and oxygen from the insulating layer 29 into the internal space sealed by the sealing member 19.
15 prevents short circuit due to electrical contact with the low melting point metal layer 31.

The low melting point metal layer 31 is formed of a low melting point metal or a low melting point alloy which melts at a temperature at which the film structure of the organic layer 10 is not destroyed, preferably at a temperature lower than the melting point of the organic material forming the organic layer 10. . Thereby, the low melting point metal layer 31 is adhered so that the sealing member 19 and the insulating layer 29 are bonded and fixed.
When is heated and melted between the sealing member 19 and the insulating layer 29, the heat can prevent the film structure of the organic layer 10 from being destroyed.

When the insulating layer 29 is formed of a glass material, the low melting point metal layer 31 is further formed of a low melting point metal or a low melting point alloy having a melting point not exceeding the glass transition point. Is desirable. In order to ensure the high-temperature durability of the formed low-melting-point metal layer 31, the low-melting-point metal or the low-melting-point alloy desirably has a melting point as high as possible within the above-mentioned melting point range.

Examples of such low melting point metals or low melting point alloys include, for example, indium, gallium, lead and the like, and low melting point alloys include, for example, aluminum-germanium alloys, indium-gallium alloys and the like. Is applicable.

The low-melting-point metal layer 31 is formed of a metal material, so that the low-melting-point metal layer 31 is sealed with the sealing member 19 while the sealing member 19 and the insulating layer 29 are bonded and fixed. Water vapor and oxygen can be prevented from entering the stopped internal space.

Next, a procedure for sealing the organic EL element 17 with the sealing member 19 in the organic EL display device 1 will be described with reference to FIGS.

First, as shown in FIG. 2, a transparent substrate 6 having a transparent electrode layer 8 and extraction electrodes 14 and 15 patterned thereon is prepared. Then, before forming the organic EL element 17 on the transparent electrode layer 8, an insulating layer 29 made of, for example, a glass material is formed on a sealing region around the transparent electrode layer 8. Here, for example, a low melting point powder glass paste 30 as a glass material is applied on the sealing region on the transparent substrate 6 and then fired to form a glass film as the insulating layer 29. Thereby, the insulating layer 2 formed as a glass coating
By 9, portions of the extraction electrodes 14 and 15 that cross the sealing region are covered in an insulating state. Here, as the low-melting-point powder glass paste 30, a mixture obtained by kneading glass powder with a binder may be used.

As described above, by forming the glass coating as the insulating layer 29 before forming the organic EL element 17, the heat of firing when forming the glass coating (the firing temperature is 4 ° C.).
(The temperature is relatively high, such as 00 ° C. or higher.)
7 can be prevented from being destroyed.

Then, as shown in FIG. 3, the transparent electrode layer 8
An insulating film 9 and an organic layer 10 that sequentially define a display pattern
Then, the back electrode layer 12 is laminated so as to be electrically connected to the extraction electrode 15 to form the organic EL element 17.

Then, as shown in FIG. 1, a low-melting-point metal or a low-melting-point alloy (hereinafter referred to as low-melting-point metal 33) is applied over the upper surface of the insulating layer 29 or the lower surface of the peripheral portion of the sealing member 19. The sealing member 19 is disposed on the insulating layer 29 in an atmosphere of dry nitrogen and dry inert gas. In this state, the gap between the sealing member 19 and the insulating layer 29 is sealed without gap by the applied low melting point metal 33 or the like.

Here, as a method of applying the low-melting point metal 33, etc., the low-melting point metal 33, etc. may be heated above the melting point and printed in a liquid state, or may be applied with a dispenser. The powder may be mixed with an organic solvent such as xylene or hexane to form a paste and applied, and then the solvent may be dried.

Then, the low melting point metal or the like 33 is heated at a temperature higher than the melting point and melted so that the lower surface of the peripheral portion of the sealing member 19 and the upper surface of the insulating layer 29 are adhered without any gap. The layer 31 is formed. Thereby, the sealing member 19 is hermetically sealed on the transparent substrate 6 by the insulating layer 29 and the low melting point metal layer 31, and the sealing member 19 is sealed by the non-moisture permeable insulating layer 29 and the low melting point metal layer 31. Water vapor or oxygen is prevented from entering the internal space sealed by the sealing member 19 from the sealing layer between the insulating layer 29 and the sealing layer.

In the organic EL display device 1 according to this embodiment, the outer peripheral side surfaces of the sealing layer (the insulating layer 29 and the low melting point metal layer 31) for sealing the sealing member 19 and the transparent substrate 6 are further formed. A moisture-proof resin may be applied so as to cover. This can prevent the low melting point metal layer 31 from being oxidized in an external environment.

Further, in the organic EL display device 1 according to this embodiment, a small amount of a moisture absorbent may be further sealed in the internal space sealed by the sealing member 19. In this way, when the sealing member 19 is sealed on the transparent substrate 6, a very small amount of water adsorbed on the sealing member 19 and entering the internal space can be removed.

In this embodiment, the case where the insulating layer 29 is formed of a glass material has been described. However, the material of the insulating layer 29 may be an insulating and non-moisture permeable inorganic material. Any material may be used. Furthermore,
Although the insulating layer 29 is limited to an inorganic material, an organic material may be used as long as the material has an insulating property and is impermeable to moisture.

<Example> Next, the above-mentioned organic EL display device 1
An example will now be described.

In this embodiment, a glass substrate (hereinafter, referred to as a glass substrate 6) is used as the transparent substrate 6. On this glass substrate 6, the wiring pattern of the transparent electrode layer 8 and the patterns of the extraction electrodes 14 and 15 are formed. It was formed by means of etching or the like using photolithography with ITO (indium tin oxide).

Then, a low-melting glass paste (here, a low-melting glass paste of ASF2300A manufactured by Asahi Glass Co., Ltd. was used) was applied as an insulating layer 29 on the sealing region of the glass substrate 6 with a transparent electrode. At 380 ° C. for 10 minutes and further at 430 ° C. for 10 minutes to form a glass film.

After the glass substrate 6 is washed by boiling using a surfactant, isopropanol, etc., copper phthalocyanine is formed as a hole injection layer on the transparent electrode layer 8 as an organic layer 10 in order from the transparent electrode layer 8 side. 400 Å, α-NPD 400 as hole transport layer
Angstrom, dimethylquinacridone 0.4% (volume percent or volume fraction) as electron transporting light emitting layer
The added aluminum quinoline complex (Alq3) was 600 Å, and lithium fluoride was 10
A film having a thickness of Å is formed by vacuum deposition by resistance heating, and the back electrode layer 1 is formed thereon.
As No. 2, a film of aluminum (Al) was formed in a thickness of 1000 angstroms by the vacuum evaporation method using resistance heating.

Then, an indium-gallium alloy (atomic ratio 9: 1, melting point 130 ° C.) as a low melting point metal 33 is applied on a glass film, and a glass plate as a sealing member 19 is disposed thereon. Then, the indium-gallium alloy was heated and melted at 140 ° C. for 3 minutes to form a low-melting-point metal layer 31 so that the glass plate and the glass coating were bonded and fixed.

When the organic EL device 1 thus manufactured was allowed to stand in the air for one week, no enlargement of a dark spot was observed in the organic layer 10.

As can be seen from the results, according to the organic EL display device 1 formed as described above, the transparent substrate 6 and the sealing member 19 are made of the insulating layer 29 made of a moisture-impermeable inorganic material and the low Since it is configured to be sealed by the sealing layer made of the melting point metal layer 31, the invasion of water vapor and oxygen from the sealing layer into the internal space is prevented, thereby increasing the reliability of the sealing function. .

At this time, since the sealing layer is formed such that the insulating layer 29 made of a non-moisture permeable inorganic material is interposed between the transparent substrate 6 and the low melting point metal layer 31, water vapor or oxygen Low melting point metal layer 3 made of a metal material to prevent the penetration of water
1 is the extraction electrodes 14 and 15 formed on the transparent substrate 6
Short circuit can be prevented.

[0038]

According to the first and second aspects of the present invention, the transparent substrate and the sealing member are configured by being sealed by the insulating layer and the metal bonding layer made of a moisture-impermeable material. In addition, the invasion of water vapor and oxygen from the insulating layer and the metal bonding layer into the internal space is prevented, so that the reliability of the sealing function can be improved.

At this time, since an insulating layer made of a non-moisture permeable material is interposed between the transparent substrate and the metal bonding layer, the metal bonding layer formed of a metal material to prevent the penetration of water vapor or oxygen is used. It is possible to prevent a short circuit with the extraction electrode formed on the transparent substrate.

Further, when the sealing member and the insulating layer or the transparent substrate are bonded by a metal bonding layer made of a metal material having a relatively low melting point, such as a metal or an alloy according to the second aspect of the present invention. Further, it is possible to prevent the film structure of the organic EL element from being destroyed by the heat generated when the metal bonding layer is formed between the sealing member and the insulating layer.

According to the invention described in claim 3, according to claim 1
Alternatively, the organic EL display device according to claim 2 can be provided.

According to the fourth aspect of the invention, when the insulating layer is formed of a glass material, at least a portion of the extraction electrode crossing the bonding region along the bonding region on the transparent substrate is insulated. After the step of forming the insulating layer, the step of forming the remaining layers constituting the organic EL element on the transparent electrode layer formed on the transparent substrate is performed. Therefore, the insulating layer is formed of a glass material. The organic layer constituting the organic EL element can be prevented from being destroyed by the heat generated at that time.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an organic EL display device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a manufacturing process of the organic EL display device according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating another manufacturing process of the organic EL display device according to the first embodiment of the present invention.

FIG. 4 is a schematic sectional view of a conventional organic EL display device.

[Explanation of symbols]

 Reference Signs List 1 organic EL display device 6 transparent substrate 8 transparent electrode layer 10 organic layer 14, 15 extraction electrode 17 organic EL element 19 sealing member 29 insulating layer 30 low melting point powder glass paste 31 low melting point metal layer 33 low melting point metal, etc.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Junichi Ono 1-7-10 Kikuzumi, Minami-ku, Nagoya-shi, Aichi F-term in Harness Research Institute, Inc. (reference) 3K007 AB11 AB13 AB18 BB01 CA01 CB01 DA01 DB03 EB00 FA02

Claims (4)

[Claims] A transparent substrate; an organic EL element formed on the transparent substrate, and an extraction electrode thereof is patterned on the transparent substrate; and a sealing member covered and disposed on the organic EL element. An insulating layer made of a non-moisture-permeable material that is formed along a bonding region on the transparent substrate to which the sealing member is bonded and covers at least a portion of the extraction electrode that crosses the bonding region in an insulating manner; Metal bonding for interposing the sealing member on the transparent substrate by interposing between the lower surface of the peripheral portion of the sealing member and the upper surface of the transparent substrate so as to cross over the extraction electrode via the insulating layer And an organic EL layer comprising:
Display device. 2. The organic EL device according to claim 1, wherein the metal bonding layer is formed of a metal such as indium, gallium, and lead, or an alloy such as an aluminum-germanium alloy and a gallium-indium alloy. Display device. 3. The organic EL according to claim 1 or claim 2.
A method of manufacturing a display device, comprising: a first step of pattern-forming the extraction electrode and a transparent electrode layer constituting the organic EL element on the transparent substrate; A second step of forming the insulating layer so as to cover at least a portion of the extraction electrode crossing the bonding region in an insulating manner; and forming the organic EL on the transparent electrode layer formed on the transparent substrate. A third step of forming the remaining layers constituting the element, and a fourth step of joining the lower surface of the peripheral portion of the sealing member to the transparent substrate via the insulating layer by the metal joining layer. A method for manufacturing an organic EL display device, comprising: 4. The insulating layer is formed of a glass material,
4. The method according to claim 3, wherein the third step is performed after the second step.