WO2008062645A1

WO2008062645A1 - Organic electroluminescent panel and sealing member

Info

Publication number: WO2008062645A1
Application number: PCT/JP2007/071308
Authority: WO
Inventors: Yuichi Iketsu
Original assignee: Konica Minolta Holdings, Inc.
Priority date: 2006-11-21
Filing date: 2007-11-01
Publication date: 2008-05-29
Also published as: JPWO2008062645A1; JP5298856B2

Abstract

A large area organic EL panel especially for use in illumination, or the like, in which uneven luminance resulting from unevenness of the applying voltage due to wiring resistance of the electrode is reduced and sealing performance for intrusion of moisture or oxygen from the outside is enhanced. The organic EL panel comprising an organic EL element having a first electrode, one or more organic thin films and a second electrode on a substrate in this order, and a sealing member covering the organic EL element has first bonding terminals in at least two first regions led out from the first electrode, and second bonding terminals in at least two second regions led out from the second electrode not overlapping the first region. In this organic EL panel, the first bonding terminals and the second bonding terminals are connected electrically with each other and have a function for bonding the sealing member to the organic EL element.

Description

Specification

Organic electoluminescence panel and sealing member

Technical field

[0001] The present invention relates to a large area light emitting organic electoluminescence (E

The present invention relates to an organic electoluminescence panel that can reduce luminance unevenness due to the wiring resistance of the electrode itself.

Background art

[0002] Organic electoluminescence (EU panel has a structure in which an organic functional thin film having carrier transport and light emission ability is sandwiched between a pair of electrodes on a substrate, and at least one of the substrate and the pair of electrodes. On the other hand, a light-transmitting material is used, and the light-transmitting electrode is made of a metal oxide typified by ITO or ZnO, and its electric resistance is lower than that of a general metal. Due to the large size, there is a problem that when the organic EL is driven, the voltage is not applied evenly, resulting in uneven brightness and a large amount of heat generation.

[0003] For this purpose, it is known to provide an auxiliary electrode on a translucent electrode (for example, Patent Document 1).

[0004] In lighting applications where the required luminance is high and the light emitting area is large, the drive current also increases, and the problems of voltage drop and heat generation due to wiring resistance are more serious. In recent years, the performance of organic EL itself has improved, and the unevenness in the applied voltage caused by the wiring resistance is directly linked to the unevenness in brightness. Therefore, only the wiring resistance reduction means in the prior art is insufficient.

[0005] In the prior art, the organic material used for the panel deteriorates by reacting with moisture and oxygen in the atmosphere. Therefore, in order to block these atmospheres, the organic EL structure portion is formed as a concave surface. It is protected by hermetically sealing with a cover having water or by attaching a film having a barrier property against moisture and oxygen (for example, Patent Document 2)

[0006] With regard to the sealing technology, the entry of moisture 'oxygen from the outside is an issue of penetration from the adhesive interface of the sealing member rather than through the sealing member itself. I was able to overcome this problem! Patent Document 1: JP 2002-156633 A

Patent Document 2: Japanese Patent Laid-Open No. 2006-228519

Disclosure of the invention

Problems to be solved by the invention

[0007] The present invention reduces unevenness in luminance caused by unevenness in applied voltage due to the wiring resistance of the electrode, and at the same time, improves sealing performance against the ingress of moisture 'oxygen from the outside, and is used particularly for illumination. The object is to obtain a large-area light emitting organic electoluminescence panel. Means for solving the problem

[0008] The above object of the present invention is achieved by the following means.

[0009] 1. On a substrate, an organic electoluminescence element having a first electrode, one or more organic thin films, and a second electrode in this order, and a sealing member that covers the organic electoluminescence element In an organic electoluminescence panel having

The first junction terminals are respectively provided in at least two first regions drawn from the first electrode, and the first junction terminals are electrically connected to each other. Each having at least two second joint terminals drawn from the two electrodes in a second region that does not overlap the first region, and each of the second joint terminals is electrically connected to each other. ,

The organic electroluminescence panel, wherein the first joint terminal and the second joint terminal also have a function of adhering the sealing member to the organic electoluminescence element.

[0010] 2. The organic element according to 1 above, wherein the joining terminal of each of the first region and the second region and the sealing member are joined by soldering or welding. Tatronore Reminescence Panerole.

[0011] 3. Resin is used to seal the sealing member and the substrate at a peripheral portion of the sealing member other than a portion to be joined to the first joining terminal and a portion to be joined to the second joining terminal. 3. The organic electoluminescence panel as described in 1 or 2 above, which is used for adhesion.

[0012] 4. a first junction terminal in the first region and a second junction terminal in the second region; The bonding of the sealing member or the bonding of the sealing member and the substrate with a resin is performed in an atmosphere with reduced moisture or oxygen concentration. The organic-elect mouth luminescence panel described in 1.

[0013] 5. A sealing member for use in the organic electoluminescence panel according to any one of 1 to 4, wherein each of the junction terminals of the first region or the second region A sealing member, wherein a terminal connected to an external power supply circuit or a circuit for controlling light emission of organic-electric-mouth luminescence is incorporated in a structure for electrically connecting the two to each other.

The invention's effect

[0014] According to the present invention, there can be obtained an organic electoluminescence panel with improved sealing performance that can suppress uneven brightness and heat generation and can sufficiently block moisture and oxygen from the outside. Brief Description of Drawings

[0015] [FIG. 1] A cross-sectional view of an example of a sealed organic EL panel.

[FIG. 2] An example of an organic EL panel according to the present invention is shown in a sectional view and a plan view.

FIG. 3 shows an example of the manufacturing process of the organic EL panel according to the present invention.

FIG. 4 is a view showing a variation example of electrode arrangement.

FIG. 5 is an explanatory diagram of a sealing method.

Explanation of symbols

[0016] 1 substrate

2 Anode

3 Organic layer

4 Cathode

5 Sealing material

6 Adhesive

7 Junction terminal

8, 9 Metal thin film layer

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the best mode for carrying out the present invention will be described in detail.

[0018] In an organic electoluminescence (EL) panel, for example, lighting applications with high required luminance and a large light-emitting area, the drive current becomes large, and the problems of voltage drop and heat generation due to wiring resistance are more serious. is there. In recent years, the performance of the organic EL panel itself has improved, and unevenness in applied voltage caused by wiring resistance is directly related to unevenness in luminance. Therefore, only the wiring resistance reducing means used in the prior art is insufficient.

[0019] On the other hand, regarding the sealing technology, the ingress of moisture 'oxygen from the outside is a problem of intrusion from the adhesive interface of the sealing member rather than through the sealing member itself. Oh! / I couldn't overcome this problem! /

[0020] In the present invention, the pair of electrodes constituting the organic EL element structure includes at least two first regions (first regions) on two opposing edges of each electrode on the substrate. From the electrode), at least two second regions (from the second electrode) are drawn. This drawn area is coated with a metal material to form a junction terminal.

[0021] Positions that match at least four edge portions so as to electrically connect the drawn first regions and the second regions, that is, the opposing regions on the same electrode. A sealing member having a connection terminal and having a short-circuit wiring for electrically connecting the opposing regions is prepared as a sealing member, and the joining terminal and the sealing member formed by coating the metal material Are joined by soldering or welding to electrically connect both ends of the first electrode and the second electrode.

[0022] The sealing member has a joint terminal at a position matching the first region and the second region, and the joint terminal is formed in the first region on the substrate. Since the first joint terminal is joined to the second joint terminal formed in the second region by welding, the joint terminal portion facing the first region of the sealing member and the The edge part other than the joining terminal part corresponding to the second region is sealed! /, N! /, And the part is sealed, and the sealing member and the substrate are bonded using, for example, a UV curable resin. By adhering, an organic EL panel with the entire periphery sealed can be obtained.

[0023] By using such a sealing member (sealing cover), both ends of the electrodes constituting the organic EL element structure can be short-circuited externally. 4 to suppress uneven brightness and heat generation. In particular, a transparent electrode made of a metal oxide such as ITO used for the anode is preferable for making the luminance uniform because the potential gradient is relaxed.

[0024] In addition, soldering, welding, and the like in the first region and the second region are performed on the portion of the edge of the substrate and the sealing member (that is, the organic EL panel) where the region is formed. Since it will be covered with metal and sealed, the part can completely block moisture and oxygen from the outside, and other parts with high sealing performance can be bonded using a resin sealing material or adhesive, By sealing, an organic EL panel with higher sealing performance compared to sealing using only a resin sealing material or adhesive can be obtained.

[0025] In addition, power can be supplied to the panel through a sealing member (sealing cover), and the sealing cover can emit light from terminals connected to the power supply circuit, fuse, booster circuit, and other organic EL. Mounting the control circuit (drive circuit) here can reduce the mounting space.

Hereinafter, embodiments of the organic EL panel of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing an example of a conventional sealed organic EL panel.

[0028] On a substrate 1 such as glass, a transparent anode 2, an organic layer 3 including a light-emitting layer that emits light by applying a potential between the electrodes, and then a cathode 4 are sequentially formed, and the organic EL device structure is further formed. An organic EL panel in which the organic EL element structure portion is sealed is obtained by adhering a sealing member 5 made of, for example, glass having a concave surface to the structure portion with an adhesive 6 around the substrate. The anode and cathode that make up the organic EL element structure are each equipped with a metal auxiliary electrode 7a at the edge of the substrate! /, Or even! /.

FIG. 2 shows an example of the organic EL panel according to the present invention in a cross-sectional view and a plan view.

[0030] After the anode 2 made of ITO, the organic layer 3, and the cathode 4 made of a metal such as aluminum are sequentially formed on the substrate 1, the two edges of the edge on the anode are directly above the lead-out portions ^. Thus, the connection terminal 7 made of a metal material is formed. The lead-out portion 2 ′ here is the first region. The lead portion ^ is a portion on the anode 2 that protrudes outward from the sealing member 5 and is provided with the auxiliary electrode 7a immediately above it. In FIG. 2, the force S, which has two locations in the first region, is not limited to this depending on the design of the auxiliary electrode, and may be four locations as described later.

[0031] The junction terminal 7 is a metal as a short-circuit means provided on the anode 2 and a sealing member 5 described later. The thin film 8 is electrically connected, and at the same time functions as an adhesive for bonding the sealing member 5 to the substrate 1. Therefore, it is preferable that the junction terminal 7 be formed of a metal material having high conductivity. Preferably, the method is not limited. However, the method is not limited. However, the connection terminal 7 is formed of solder or a sealing material. (Silver paste) containing conductive fine particles, for example, silver fine particles or the like, may be formed by applying a conductive adhesive as it is to a desired shape as a metal material, or by sputtering, vapor deposition, etc. using a mask. A slightly thick (several hundred nm to several μm) metal thin film can be formed! / ,.

[0032] In assembling the sealing member (sealing cover) 5, first, the edge portion (first region) of the anode 2 or the edge portion (second region) of the cathode 4 and the sealing member 5 are joined to each other by the joining terminal 7, and the same electrodes are connected to each other through the metal thin film layer 8 (anode short-circuit wiring) and the metal thin film layer 9 (cathode short-circuit wiring) formed on the front and back surfaces of the sealing member 5. Connect electrically.

[0033] In Fig. 2 (a), the anode 2 constituting the organic EL element structure is provided with metal junction terminals 7 at two positions of the leading edge ^ of the cathode edge on the substrate, respectively. Na

[0034] On the inner surface of the glass sealing member 5, as shown in the sectional view, a metal thin film layer 8 having an auxiliary electrode width that crosses the sealing member 5 so that the junction terminals 7 can be electrically connected to each other. The opposite end portions of the anode 2 and the metal thin film layer 8 are joined together by soldering or sealing joining terminals 7, and both ends of the joining terminals are electrically connected (anode short-circuit wiring). .

Further, another metal thin film layer 9 is formed on the outer surface side of the sealing member opposite to the inner side provided with the metal thin film layer 8 so as to be orthogonal to the metal thin film layer 8, as shown in FIG. Although not shown in the cross-sectional view, a lead-out portion (second region) provided at two ends of the side of the cathode 4 where the auxiliary electrode of the anode is not formed, and the metal thin film layer 9 are Again, they are joined by soldering or sealing joint terminals 7 and are electrically connected (cathode short-circuit wiring).

[0036] The form (shape) of the metal thin film layer 8 is not specified. As long as conduction can be achieved, the lead wire need not be a thin film, or a connection consisting of a plurality of lead wires may be used. However, the connection between the junction terminals of the anode short-circuit wiring and cathode short-circuit wiring and the respective auxiliary electrodes by soldering or sealing forms a continuous end to seal a predetermined area around the substrate. Therefore, it is preferable that the short-circuit wiring is composed of a metal thin film layer having a predetermined area. Therefore, it is preferable that the sealing member (sealing cover) 5 covers most of the front and back surfaces of the base material with the metal thin film layer so that the opposite edge portions are electrically connected to each other.

[0038] The metal thin film 8 or 9 serving as the short-circuit wiring of the anode 2 or! / Is the conductive metal, for example, a metal thin film such as silver, gold, platinum, copper or nickel, and is sputtered or deposited. It is possible to form a desired pattern on the sealing member by a method such as the above, or by forming a metal fine particle paste. In addition, a metal thin film may be produced by a plating method.

[0039] resistivity of the metal thin film 8 or 9 is desirably less 1 Χ 10_ ⁷ Ω πι.

[0040] The area of each metal thin film layer 8 or 9 is preferably 30% or more of the area of the connecting portion of the sealing member 5, preferably 50% or more, more preferably 70% or more. Most preferably. The width of the metal thin film 8 or 9 is preferably 30% or more, more preferably 50% or more, more preferably 70% of the length of one side of the connecting portion of the sealing member 5 70% The above is most preferable.

[0041] The sealing member 5 having the metal thin film 8 or 9 and the joining terminal 7 formed on the edge of the panel are provided by joining by soldering or fusion of the respective metals themselves. Is preferred.

[0042] Since the joining terminal 7 at the edge of the panel is joined or sealed with metal, the other part, that is, the part where the metals are not joined (the shoulder part in the plan view of FIG. 2). Seal the organic EL panel with adhesive at 4 locations.

[0043] As the adhesive, a heat or light (UV) curable adhesive such as epoxy or acrylic is used with a force S.

[0044] Since the organic EL panel sealed in this way is bonded with a metal material in most of the surroundings (for example, the four sides), the airtightness of this part is high. Since it has high sealing performance against gases such as air, oxygen, and water vapor, an organic EL panel with high sealing performance that can sufficiently block moisture and oxygen from the outside as a whole can be obtained.

FIG. 2 (b) is the same as FIG. 2 (a), except that the junction terminal 7, the metal auxiliary electrode 7a, and the binding member.

It consists of 7b. The metal auxiliary electrode 7a is produced by processing a metal tape or the like on a lead-out portion on the anode 2, and then, as a binding member 7b, a solder or conductive contact Seal with adhesive and join with sealing member 5. By adopting such a configuration, the electrical resistance can be further lowered and the sealing effect can be enhanced.

[0046] The rest of the configuration is the same as FIG. 2 (a).

Hereinafter, embodiments of the present invention will also be described with reference to the drawings.

FIG. 3 shows the manufacturing process of the organic EL panel according to the present invention.

FIG. 3 (a) shows a state where a transparent electrode (anode) is formed on the substrate.

[0050] Substrates may be glass that is transparent, and materials other than glass, such as polycarbonate (PC), polyethylene terephthalate (PET), polyethylene naphthalate (PE

N) or other plastic may be used. There is no limitation on the size and thickness of the substrate.

[0051] For example, an anode (first electrode) 2 is fabricated on an anoleic glass (100 X 100mm, tO. 7mm) (Fig. 3 (a)).

That is, ITO was formed as a transparent electrode with a thickness of 120 nm by a sputtering method. Next, Ni is sputtered to a thickness of 500 nm by sputtering to both ends of the ITO pattern (first region) and the second region that does not contact the ITO pattern (Fig. 1, both left and right ends). Formed as junction terminal 7. For ITO and Ni patterning, a mask was used during film formation (Fig. 3 (a)).

[0053] The transparent electrode may be a metal thin film such as IZO, Nesa film or Au! /. The material of the auxiliary electrode may be a metal such as Fe, Cu, Pb, Zn, Sn, Al, or an alloy or laminated film thereof. The method of film formation is not limited for both transparent electrodes and junction terminals, and PVD, CVD, printing, etc. may be used. Further, the patterning method and the film thickness are not limited.

[0054] Fig. 4 (a) shows a variation (example) of the transparent electrode and the joining terminal arrangement pattern.

Next, an organic layer 3 is formed on the anode 2. The hole transport layer is αnmPD as a layer with a thickness of 15 nm and the light emission layer as Alq with a thickness of 30 nm as a pattern by vapor deposition using a mask (Fig. 3 (b)).

[0056] [Chemical 1]

FIG. 4 (b) shows an example in which an organic layer is formed as an example in which the electrode arrangement pattern is changed.

[0058] The configuration of the organic layer 3 is not particularly limited except that it includes at least one light emitting layer. That is, in the simplest case, only the light emitting layer is provided, and for example, a charge injection layer / transport layer, a charge blocking layer, etc. may be added. Each layer may be a mixed layer (co-deposited layer) made of a plurality of materials. Also, there are no particular limitations on the film thickness and film formation method of each layer, such as vapor deposition and coating.

After the organic layer is formed, a cathode (second electrode) 4 is formed (FIG. 3 (c)).

[0059] As the cathode 4, A1 is deposited to a thickness of 200 nm by resistance heating vapor deposition. Further, the cathode is formed so as to be in contact with and electrically connected to the junction terminal of the second region formed previously. Use a mask for patterning.

[0060] Before forming the cathode, Li, Ca, Cs, or an oxide or fluoride thereof may be formed as a buffer layer. Further, co-evaporation of the above material and the cathode material may be used. As a material for the cathode, a metal having a work function smaller than 4 eV is suitable. Magnesium, aluminum, and the like, and magnesium / silver, lithium / aluminum, etc., are typical examples of alloys. The film thickness and the film forming method can be mask vapor deposition, photolitho patterning, plating, printing, etc., but are not limited.

Next, a sealing member (sealing cover) was prepared.

[0062] One side of a glass substrate having a thickness of 1 · 1 mm is cut into a cap shape by cutting a depth of 0.5 · 5 mm by the sand blast method. Figure 3 (d) shows a cross-sectional view.

[0063] On the outer side (outer surface) and inner side (inner surface) of the sealing member, anode junction terminals (provided in the first region) and cathode junction terminals (provided in the second region), respectively. ) Electrically A pattern of Ni short-circuit wiring (anode short-circuit wiring, cathode short-circuit wiring) that can be connected was provided.

[0064] The method for forming the short-circuit wiring was the same as the junction terminal, using the sputtering method (thickness 500nm).

. The short-circuit wiring pattern was also formed on the cross-section of the sealing member as shown in Fig. 3 (d).

[0065] The material of the sealing member is not limited to glass, and a cap-like structure is not essential. In this case, care must be taken that the short-circuit wiring (anode short-circuit wiring) that connects the junction terminals formed on the sealing member does not contact the cathode of the organic EL!

[0066] If the junction terminals are arranged as shown in Fig. 4 (c), the short-circuit wires of the anode and the cathode do not intersect (Fig. 4 (d), left), so that both short-circuit wires are connected to the same surface, for example, outside (Outer surface) can be formed.

[0067] The material of the short-circuit wiring is not necessarily limited to Ni, and the same material and forming method as those of the above-mentioned junction terminal can be used as they are. Of course, the parts that will be joined to the junction terminals later and the material that short-circuits them are different.

[0068] Further, the sealing member (sealing cover) itself may be an FPC (flexible printed circuit board) or COF (Chip on Film) on which a power supply terminal or an organic EL drive circuit is mounted.

[0069] The right figure of FIG. 4 (d) shows an example using an FPC (flexible printed circuit board) as a sealing member corresponding to the electrode arrangement of the right figure of FIG. 4 (c). A copper electrode is formed at the position where it is connected to the junction terminal, and an IC chip with a built-in drive circuit (boost circuit, low current circuit, overcurrent protection circuit, etc.) is mounted on the substrate. Using multi-layer FPC, connection to each junction terminal can be realized inside the FPC.

Next, the sealing method will be described with reference to FIG.

[0071] Sealing of the element having the electrode and junction terminal arrangement shown in Figs. 3 (a) to (c) will be described.

[0072] As shown in Fig. 5 (1), the organic EL element substrate and the sealing member are held together, and the joint connected to the junction terminal of the anode short-circuit wiring, and the position where the junction terminal is indicated by the dotted line in the solder bath Immerse until joining. The other side of the anode short-circuit wiring is bonded in the same manner, and the cathode is also bonded in the same manner by immersing each side in the solder bath.

[0073] Fig. 5 (2) shows a cross-sectional view of the soldered organic EL panel. [0074] Cannot be soldered! /, Where UV curing resin (for example, photo-curing resin (WorldRock Model No. 72A14: manufactured by Kyoritsu Chemical Industry Co., Ltd.)) is potted with a dispenser, and UV irradiation device Then, cure with UV irradiation and seal (Fig. 5 (3)).

[0075] These processes are preferably carried out under an inert gas atmosphere of deoxygenated and dehydrated, for example, nitrogen.

[0076] When the substrate of the organic EL panel or the sealing member is formed into a film, the joining terminal 7 of the cathode 4 and the joining terminal of the anode short-circuit line of the sealing member are made using a solder (YAG laser). , High power semiconductor laser, etc.) and alloying and welding may be performed seamlessly by resistance heating (Fig. 5 (4)). The figure shows an example in which the cathode short-circuit wiring and the junction terminal are welded. The resin that fills the gap is not limited to UV curable resin!

Although the organic EL panel according to the present invention has been described above with respect to its structure and manufacturing method, the present invention is of course not limited thereto. According to the present invention, by providing anode short-circuit wiring or cathode short-circuit wiring, luminance unevenness due to applied voltage unevenness due to electrode wiring resistance can be reduced, and connection of junction terminals by short-circuit wiring can be used from the outside. This improves the sealing performance against the intrusion of moisture and oxygen, and this reduces the brightness unevenness especially in large-area organic EL panels, improving the sealing performance. Can be obtained.

Claims

The scope of the claims

[1] An organic electoluminescence element having a first electrode, one or more organic thin films, and a second electrode in this order on a substrate, and a sealing member that covers the organic electoluminescence element, In the organic electoluminescence panel having

[2] The first aspect of the invention according to claim 1, wherein the joining terminal of each of the first region and the second region and the sealing member are joined by soldering or welding. Organic Elect Mouth Luminescence Panel.

[3] The sealing member and the substrate are bonded using a resin at a peripheral portion of the sealing member other than a portion to be joined to the first joining terminal and a portion to be joined to the second joining terminal. The organic electoluminescence panel according to claim 1 or 2, wherein the organic electroluminescence panel according to claim 1 or 2 is used.

[4] The bonding between the first bonding terminal in the first region and the second bonding terminal in the second region and the sealing member, or the bonding between the sealing member and the substrate by resin is moisture or The organic electoluminescence panel according to any one of claims 1 to 3, which is performed in an atmosphere with a reduced oxygen concentration.

[5] A sealing member for use in the organic electoluminescence panel according to any one of claims 1 to 4, wherein each of the first region and the second region is used. A sealing member in which a terminal connected to an external power supply circuit or a circuit for controlling light emission of organic electroluminescence is incorporated in a structure in which the joint terminals are electrically connected to each other.