WO2012140924A1

WO2012140924A1 - Organic electroluminescence device and method for manufacturing organic electroluminescence device

Info

Publication number: WO2012140924A1
Application number: PCT/JP2012/050826
Authority: WO
Inventors: 崇人小山田
Original assignee: パイオニア株式会社
Priority date: 2011-04-12
Filing date: 2012-01-17
Publication date: 2012-10-18
Also published as: WO2012140736A1

Abstract

This organic electroluminescence device includes: a first electrode disposed on a substrate; an organic functional layer comprising at least one layer disposed on the first electrode; a second electrode disposed on the organic functional layer; a low-melting-point material layer, which is disposed on the second electrode, and which comprises an insulator that takes on a solid state at normal temperature and has a lower melting point than the glass transition temperature of the organic material constituting the organic functional layer; and a sealing layer for sealing a laminate comprising the first electrode, the organic functional layer, the second electrode and the low-melting-point material layer.

Description

ORGANIC ELECTROLUMINESCENT DEVICE AND METHOD FOR PRODUCING ORGANIC ELECTROLUMINESCENT DEVICE

The present invention relates to an organic electroluminescence device and a manufacturing method thereof.

Conventional technology

An organic electroluminescence device (hereinafter referred to as an organic EL device) is a self-luminous surface light-emitting device, and has high visibility, can be driven at a low voltage, and has a broad emission spectrum. Research into the practical use of this is being actively conducted. The organic EL device is configured, for example, by sequentially laminating a first electrode (anode), a hole transport layer, a light emitting layer, an electron transport layer, and a second electrode (cathode) on a glass substrate. An organic EL device is a device that obtains electroluminescence by current injection, and requires a larger current to flow than an electric field device such as a liquid crystal display.

問題 Dark spot defects are a problem with organic EL devices. A dark spot is an irreversible non-light emitting portion that occurs in a light emitting area when an organic EL device is used for a long time. The dark spot is considered to be generated by partial deactivation of the organic EL element due to moisture and oxygen entering from the outside, and outgas emitted from the constituent material of the device. Such intrusion and outgas such as moisture and oxygen from the outside are dealt with by adopting a hollow sealing structure in which the organic EL element is sealed with a metal can together with an adsorption desiccant (Patent Document 1). reference).

Another problem with organic EL devices is current leakage between electrodes. In the organic EL device, since the thickness of the organic functional layer provided between the anode and the cathode is on the order of submicron, current leakage may occur due to minute dust or defects in the organic functional layer. For example, when a foreign substance is mixed between the anode and the cathode, the foreign substance may form a leak path, or the pattern may be lost in the electrode due to the foreign substance, resulting in contact between the anode and the cathode. When a current leak occurs, a non-light emitting portion may be generated, or damage may spread to surrounding cells due to heat generation.

Patent Documents

2 and 3 disclose a technique for repairing a short-circuit portion by applying a reverse bias voltage between electrodes to melt and evaporate an electrode material that forms a leak portion.

In Patent Document 4, a peeling suppression film made of an organic conductive material is formed between a lower electrode and an organic light emitting layer, and the peeling suppression layer is evaporated by laser irradiation to form a cavity, thereby repairing a short circuit portion. Techniques for performing are disclosed.

Japanese Patent Laid-Open No. 9-148066 Japanese Patent Laid-Open No. 11-305727 JP 2003-229262 A JP 2006-269108 A

The above-described repair of the short-circuit portion by reverse bias or laser irradiation is considered to be effective when the sealing structure of the organic EL device is a hollow sealing structure. This is because, in the case of the hollow sealing structure, there is a space for evaporating and scattering the electrode material (metal) and foreign matter to be removed by laser irradiation. However, in recent years, demands for thinner and more flexible devices are increasing, and it is difficult to meet these requirements with a hollow sealing structure.

A solid sealing structure is known as a sealing structure that can reduce the thickness of a device. Some solid sealing structures are sealed with a plate made of glass, metal, or the like, and others are sealed with a thin film made of an inorganic material such as SiO ₂ or SiN _x . In the solid sealing structure, since the sealing layer is in intimate contact with the upper electrode, it is possible to reduce the thickness, and there is an advantage that the device has high heat dissipation, while the electrode is interposed between the upper electrode and the sealing layer. Since there is no space for evaporating and scattering the material, it is difficult to repair the short-circuit portion by reverse bias or laser irradiation. When such a repair is performed in the solid sealing structure, the sealing layer may be destroyed by an impact accompanying the fracture of the upper electrode, and the sealing function may be impaired. Moreover, even when such a repair is performed and the current leak is resolved, there is a possibility that the current leak may reoccur due to the upper electrode and the lower electrode coming into contact again by pressing from the sealing layer that is in close contact with the upper electrode.

As described above, the solid sealing structure has advantages such as thinning of the device and improvement of heat dissipation, but it is difficult to execute the repair method performed in the hollow sealing structure such as reverse bias and laser irradiation. ing.

The present invention has been made in view of the above points, and even in a device having a solid sealing structure, it is possible to easily and effectively repair a short-circuit portion generated between the upper electrode and the lower electrode. An object of the present invention is to provide an organic electroluminescent device and a method for producing such an organic electroluminescent device.

An organic electroluminescence device according to the present invention includes a first electrode provided on a substrate, an organic functional layer including at least one layer provided on the first electrode, and a first electrode provided on the organic functional layer. An organic EL structure including two electrodes, and an insulation provided on the second electrode and having a melting point lower than a glass transition temperature of an organic material that exhibits a solid state at room temperature and constitutes the organic functional layer A low-melting-point material layer, and a sealing layer that seals the laminate composed of the organic EL structure and the low-melting-point material layer, and the low-melting-point material layer has a general formula of C _n F _{2n + 2} It is characterized by comprising a compound containing a chain saturated fluorine represented by the formula:

Another organic electroluminescence device according to the present invention includes a first electrode provided on a substrate, an organic functional layer including at least one layer provided on the first electrode, and the organic functional layer. An organic EL structure including the second electrode provided; a cover layer made of an inorganic material that covers the organic EL structure; provided on the cover layer; and exhibiting a solid state at room temperature; Sealing a low-melting-point material layer made of an insulator having a melting point lower than the glass transition temperature of the organic material constituting the organic functional layer, and a laminate comprising the organic EL structure, the cover layer, and the low-melting-point material layer And a sealing layer.

In addition, the organic electroluminescence device manufacturing method according to the present invention includes a step of forming a first electrode on a substrate, a step of forming an organic functional layer including at least one layer on the first electrode, and the organic function. A step of forming a second electrode on the layer, and a low-resistance comprising an insulator that exhibits a solid state at room temperature on the second electrode and has a melting point lower than the glass transition temperature of the organic material constituting the organic functional layer Forming a melting point material layer; and forming an intermediate device by forming a sealing layer that seals a laminate including the first electrode, the organic functional layer, the second electrode, and the low melting point material layer; And heating the intermediate device at a temperature higher than the melting point of the low melting point material constituting the low melting point material layer.

In addition, another method of manufacturing an organic electroluminescence device according to the present invention includes a step of forming a first electrode on a substrate, a step of forming an organic functional layer including at least one layer on the first electrode, A step of forming a second electrode on the organic functional layer; and an insulator that exhibits a solid state at room temperature on the second electrode and has a melting point lower than the glass transition temperature of the organic material constituting the organic functional layer Forming a low-melting-point material layer, and forming a sealing layer that seals the laminate composed of the first electrode, the organic functional layer, the second electrode, and the low-melting-point material layer to obtain an intermediate device A step of identifying a short-circuit portion between the first and second electrodes, and a step of irradiating the short-circuit portion with a laser to remove the short-circuit portion.

Another method for manufacturing an organic electroluminescent device according to the present invention is a method for manufacturing an organic electroluminescent device, comprising: forming a first electrode on a substrate; and at least one layer on the first electrode. A step of forming an organic functional layer, a step of forming a second electrode on the organic functional layer, a glass of an organic material that forms a solid state on the second electrode at room temperature and constitutes the organic functional layer A step of forming a low-melting-point material layer made of an insulator having a melting point lower than a transition temperature, and a laminate made up of the first electrode, the organic functional layer, the second electrode, and the low-melting-point material layer; Forming a sealing layer to obtain an intermediate device; identifying a short-circuit location between the first and second electrodes; and passing the first and second currents through the short-circuit location. It is characterized in that it comprises a step of removing the short-circuit portion by applying a power, the between 2 electrodes.

It is sectional drawing which shows the structure of the organic electroluminescent device which concerns on the Example of this invention. 2A is a cross-sectional view of an organic electroluminescence device according to an embodiment of the present invention in which a short circuit has occurred, and FIG. 2B is a cross-sectional view of the organic electroluminescence device according to an embodiment of the present invention after the repair of the short circuit portion. It is sectional drawing. 3A is a cross-sectional view of an organic electroluminescence device according to an embodiment of the present invention in which a short circuit has occurred, and FIG. 3B is a cross-sectional view of the organic electroluminescence device according to an embodiment of the present invention after the repair of the short circuit portion. It is sectional drawing. FIG. 4 is a manufacturing process flow diagram of an organic electroluminescence device according to an embodiment of the present invention. FIG. 5 is a manufacturing process flow diagram of an organic electroluminescence device according to an embodiment of the present invention. FIG. 6 is a manufacturing process flow diagram of an organic electroluminescence device according to an embodiment of the present invention. FIG. 7 is a cross-sectional view showing a configuration of an organic electroluminescence device according to another embodiment of the present invention. FIG. 8 is a cross-sectional view showing a configuration of an organic electroluminescence device according to another embodiment of the present invention. FIG. 9 is a cross-sectional view showing a configuration of an organic electroluminescence device according to another embodiment of the present invention. FIG. 10 is a diagram showing a specific example of the fluorinated alkane constituting the low melting point material layer according to the example of the present invention. It is a figure which shows the characteristic evaluation result after high temperature leaving of the organic electroluminescent device which concerns on the Example of this invention.

An organic electroluminescence device according to the present invention includes a first electrode provided on a substrate, an organic functional layer including at least one layer provided on the first electrode, and a second electrode provided on the organic functional layer. A low-melting-point material layer made of an insulator provided on the second electrode and having a melting point lower than the glass transition temperature of the organic material that exhibits a solid state at room temperature and constitutes the organic functional layer, and the first electrode, And a sealing layer that seals the laminate composed of the organic functional layer, the second electrode, and the low-melting-point material layer.

According to the configuration of the organic electroluminescence device of the present invention, it is possible to easily and effectively repair the short circuit portion. That is, when the foreign matter mixed between the first electrode and the second electrode forms a current leak path, the foreign matter is reduced by heating the organic electroluminescence device and melting the low melting point material layer. It is embedded with an insulator constituting the melting point material layer. Thereafter, the temperature is lowered to solidify the low-melting-point material layer, so that the state where the foreign matter is embedded with the insulator is maintained. Therefore, current leakage between the first electrode and the second electrode can be prevented.

In addition, by heating the organic electroluminescence device to melt the low melting point material layer, the second electrode can be broken so as to open toward the low melting point material layer. However, it is possible to remove the short-circuit portion by laser irradiation, power application, or the like.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings shown below, substantially the same or equivalent components and parts are denoted by the same reference numerals.

FIG. 1 is a cross-sectional view showing the structure of an organic EL device 1 according to an embodiment of the present invention. The organic EL device 1 is formed by sequentially laminating a first electrode (lower electrode) 12, an organic functional layer 14, a second electrode (upper electrode) 16, a low melting point material layer 18, and a sealing layer 20 on a substrate 10. Is done. The organic EL device 1 is a so-called bottom emission type light emitting device that extracts light generated in the organic functional layer 14 from the substrate 10 side.

The substrate 10 is made of a light transmissive material such as glass. For the first electrode 12 as an anode, a conductive oxide having a light transmission property such as ITO (Indium （Tin Oxide) or IZO (Indium Zinc Oxide) having a thickness of about 100 nm is formed on the substrate 10 by sputtering, for example. Thereafter, it is formed by patterning by etching.

The organic functional layer 14 is configured by laminating a hole injection layer, a hole transport layer, a light emitting layer, and an electron injection layer in this order so as to cover the first electrode 12 on the substrate 10. The hole injection layer is made of, for example, copper phthalocyanine (CuPc) having a thickness of about 25 nm, and the hole transport layer is made of, for example, α-NPD (Bis [N- (1-naphthyl) -N-pheny] benzidine) having a thickness of about 40 nm. The light emitting layer is made of, for example, Alq3 (tris- (8-hydroxyquinoline) aluminum) having a thickness of about 60 nm, and the electron injection layer is made of, for example, lithium oxide (Li ₂ O) having a thickness of about 0.5 nm. The Each of the layers constituting the organic functional layer 14 can be formed by, for example, a mask vapor deposition method or an ink jet method.

The second electrode 16 serving as a cathode is formed by depositing Al having a thickness of about 100 nm on the substrate 10 so as to cover the organic functional layer 14 by a mask vapor deposition method or the like. As another material of the second electrode 16, an alloy having a relatively low work function such as Mg—Ag or Al—Li is preferable. Further, by making the second electrode 16 have a laminated structure of Al and Ag, it is possible to improve the light extraction efficiency while maintaining high adhesion to the organic functional layer 14 regardless of the lamination order. An organic EL structure is formed by the first electrode 12, the organic functional layer 14, and the second electrode 16.

The low melting point material layer 18 is made of an insulator that exhibits a solid state at room temperature (about room temperature, for example, around 25 ° C.) and has a melting point lower than the glass transition temperature Tg of each of the above materials constituting the organic functional layer 14. . The low melting point material layer 18 can be made of, for example, a material (for example, wax) mainly composed of paraffin. Paraffin is a mixture of methane-based hydrocarbons having 16 to 40 carbon atoms, and has a melting point of about 50 to 75 ° C. As another material of the low melting point material layer 18, for example, tri-p-tolylamine can be used. Tri-p-tolylamine has a melting point of 117 ° C. and is an organic polymer soluble in an organic solvent, and can form a film using an organic solvent solution as a coating solution. The low melting point material layer 18 is formed so as to cover the entire upper surface of the second electrode 16.

The sealing layer 20 is composed of a thin film made of an inorganic material such as SiNx, SiON, SiOx, AlOx, or AlN. The sealing layer 20 is provided in close contact with the low-melting-point material layer 18 and seals a laminate including the first electrode 12, the organic functional layer 14, the second electrode 16, and the low-melting-point material layer 18 on the substrate 10. Stop. The sealing layer 20 plays a role of preventing entry of oxygen and moisture from the outside. Examples of the method for forming the sealing layer 20 include vapor deposition, sputtering, and CVD. In particular, the CVD method has good coverage and can easily form a highly moisture-proof film.

Hereinafter, a method for repairing the short-circuit portion in the organic EL device 1 according to the present embodiment will be described. In the organic EL device 1 according to the present embodiment, the short-circuit portion can be repaired by two repair methods. First, the first repair method will be described.

FIG. 2A shows that the organic functional layer 14 between the first electrode 12 and the second electrode 14 is mixed with the conductive foreign matter 30, thereby causing a pattern defect in the organic functional layer 14 and the second electrode 16. It is sectional drawing which illustrates the state which exists. In such a state, the second electrode 16 can be electrically connected to the first electrode 12 through the conductive foreign material 30. That is, in the case shown in FIG. 2A, the conductive foreign material 30 can be a short-circuit portion that forms a current leak path. When a current leak path is formed between the first electrode 12 and the second electrode 16, current injection into the organic function 14 is hindered, resulting in a decrease in light emission luminance or no light emission.

First, the organic EL device 1 in the state shown in FIG. The heating temperature is set to be not less than the melting point of the low melting point material constituting the low melting point material layer 18 and not more than the glass transition temperature Tg of each material constituting the organic functional layer 14. For the heat treatment, a hot plate, a constant temperature layer, a belt furnace, or the like can be used. By performing such heat treatment, the low melting point material constituting the low melting point material layer 18 is melted to become a liquid. The liquid low melting point material is impregnated into the gap between the conductive foreign matter 30 and the organic functional layer 14 and the second electrode 14 to embed the conductive foreign matter 30.

Next, the organic EL device 1 is returned to room temperature (about room temperature). Thereby, the low melting point material is solidified in a state where the conductive foreign material 30 is embedded. Since the conductive foreign material 30 is covered with a low melting point material which is an insulator and does not function as a current leak path, it is possible to prevent current leakage. FIG. 2B is a cross-sectional view of the organic EL device 1 repaired by the first repairing method. After the low melting point material is solidified, as long as the organic EL device 1 is used in a room temperature environment, the state shown in FIG. Further, since the heating temperature is set to be equal to or lower than the glass transition temperature Tg of each material constituting the organic functional layer 14, the organic functional layer 14 is not damaged.

As described above, in the first repair method, the low melting point material layer 18 is melted by heating the organic EL device 1, and the foreign matter mixed between the first electrode 12 and the second electrode 16 is removed from the low melting point material. By covering with the insulator constituting the layer 18, the occurrence of current leakage is prevented. In the first repair method, the repair of the short circuit portion is completed only by the heat treatment of the organic EL device 1. The low melting point material layer 18 is generated by applying a power so as to be forward biased or reverse biased between the first electrode 12 and the second electrode 16 so as to cause a local current to flow through the shorted part to generate heat. May be melted. Such power application can be performed instead of the above heat treatment or together with the heat treatment.

Next, a second method for repairing the short circuit portion will be described. FIG. 3A is a cross-sectional view showing a state in which the second electrode 16 has entered a defect (pinhole) or the like generated in the organic functional layer 14 and the first electrode 12 and the second electrode 16 are short-circuited. is there.

First, the organic EL device 1 in the state shown in FIG. The heating temperature is set to be not less than the melting point of the low melting point material constituting the low melting point material layer 18 and not more than the glass transition temperature Tg of each material constituting the organic functional layer 14. For the heat treatment, a hot plate, a constant temperature layer, a belt furnace, or the like can be used. By performing such heat treatment, the low melting point material constituting the low melting point material layer 18 is melted to become a liquid.

Next, the short-circuit part 31 is irradiated with laser light while the organic EL device 1 is heated at the above heating temperature. The position of the short-circuit portion 31 can be specified by digitizing an output image of a camera that captures the light emitting area of the organic EL device 1 and performing image processing on the digital image. The laser beam is irradiated from the substrate 10 side with a power for melting and evaporating the second electrode 16. The metal that is the constituent material of the second electrode 16 forming the short-circuit portion 31 absorbs the laser beam and generates heat to melt and evaporate. At this time, since the low melting point material layer 18 is melted by the heat treatment, the second electrode 16 is positioned upward (low melting point material layer as shown in FIG. 3B while avoiding the destruction of the sealing layer 20. It can be broken and deformed so as to open toward the side. The short-circuit portion 31 is removed by melting and evaporation together with the second electrode 16 by laser irradiation. The defective portion of the organic functional layer 14 from which the short-circuit portion 31 has been removed is impregnated with a liquid low melting point material.

Next, the organic EL device 1 is returned to room temperature (about room temperature). The low-melting-point material constituting the low-melting-point material layer 18 is solidified in a state of embedding the broken portion of the second electrode 16 that is broken so as to open upward (low-melting-point material layer side). The defective portion of the organic functional layer 14 is filled with a low-melting material in a solid state. As a result, occurrence and recurrence of current leakage can be prevented. FIG. 3B is a cross-sectional view of the organic EL device 1 repaired by the second repair method. After the low melting point material is solidified, as long as the organic EL device 1 is used in a room temperature environment, the state shown in FIG. Further, since the heating temperature is set to be equal to or lower than the glass transition temperature Tg of each material constituting the organic functional layer 14, the organic functional layer 14 is not damaged. Further, since the laser irradiation is performed while heating the organic EL device 1, the impact due to the fracture of the second electrode is absorbed by the liquid low-melting-point material layer 18. Thereby, destruction of the sealing layer 20 is prevented.

As described above, in the second repairing method, the organic EL device 1 is heated to melt the low melting point material layer 18 so that the second electrode 16 is opened upward (low melting point material layer side). While maintaining the obtained state, the short circuit part is melted and evaporated together with the second electrode 16 to remove the short circuit part. In addition, by applying electric power so that the first electrode 12 and the second electrode 16 are forward-biased or reverse-biased while the organic EL device 1 is heated, a current is caused to flow locally in the short-circuit portion 31 and the short-circuit portion 31. It is also possible to remove this by melting and evaporating. Such power application can be performed in place of or with the laser irradiation described above. In the above description, the case where the short-circuit portion formed by the electrode material invading the defect portion generated in the organic functional layer 14 is illustrated as an example. As illustrated in FIG. Even when the foreign matter mixed between the electrode 12 and the second electrode 16 is removed, the repair by the second repair method is possible. In the above description, the laser irradiation is performed while heating the organic EL device. However, the laser irradiation can be performed alone. Also in this case, since the low melting point material layer 18 is heated and melted by the laser irradiation, it is possible to remove the short-circuit portion as in the case involving the heat treatment described above.

Hereinafter, a method for manufacturing the organic EL device 1 according to an embodiment of the present invention will be described. FIG. 4 is a manufacturing process flow chart of the organic EL device according to the embodiment of the present invention including the repair process of the short circuit portion by the first repair method described above.

A light-transmitting conductive oxide such as ITO or IZO is deposited on the light-transmitting substrate 10 made of glass or the like by a sputtering method, for example, to a thickness of about 100 nm, and this is patterned into a desired shape by etching. The electrode 12 is formed (step S1).

Next, an organic functional layer 14 is formed by sequentially forming a hole injection layer, a hole transport layer, a light emitting layer, and an electron injection layer on the first electrode 12 by an inkjet method, a mask vapor deposition method, or the like. The hole injection layer is made of, for example, copper phthalocyanine (CuPc) having a thickness of about 25 nm, and the hole transport layer is made of, for example, α-NPD (Bis [N- (1-naphthyl) -N-pheny] benzidine) having a thickness of about 40 nm. The light emitting layer is made of, for example, Alq3 (tris- (8-hydroxyquinoline) aluminum) having a thickness of about 60 nm, and the electron injection layer is made of, for example, lithium oxide (Li ₂ O) having a thickness of about 0.5 nm. (Step S2).

Next, a resist mask having an opening is formed in the formation region of the second electrode, and Al as an electrode material is deposited on the structure obtained through each of the above steps by vapor deposition or the like. Thereafter, the resist mask is removed together with unnecessary portions of Al to pattern the Al film, thereby forming the second electrode 16 on the organic functional layer 14 (step S3).

Next, a low melting point material layer 18 is formed on the second electrode 16. Specifically, paraffin, which is a low melting point material, is heated and melted, and liquid paraffin is applied and formed on the second electrode 16. At this time, by heating the structure through the above steps at a temperature higher than the melting point of paraffin, the liquid paraffin uniformly spreads on the second electrode 16 and the layer thickness of the low melting point material layer 18 is uniform. (Step S4).

Another method for forming the low melting point material layer 18 is a method in which powder paraffin is dispersed on the second electrode 16 and then the substrate 10 is heated to melt the powder paraffin to form a film.

Tri-p-tolylamine can also be used as the material of the low melting point material layer 18. In this case, a film formed by dissolving tri-p-tolylamine in an organic solvent is applied onto the second electrode 16 as a coating solution. Thereafter, a heat treatment at about 50 ° C. is performed to dry the coating solution.

Next, it is made of an inorganic material such as SiNx, SiON, SiOx, AlOx, AlN so as to entirely cover the structure obtained through each of the above steps by a plasma CVD method capable of isotropic film formation. The sealing layer 20 is formed (Step S5).

Next, the intermediate device obtained through the above steps is heated. The heating temperature is set to a temperature not lower than the melting point of the low melting point material constituting the low melting point material layer 18 and not higher than the glass transition temperature Tg of each material constituting the organic functional layer 14. For the heat treatment, a hot plate, a thermostatic layer, a belt furnace, or the like that can heat the intermediate device as a whole can be used. When the low-melting-point material layer 18 is made of, for example, paraffin, for example, heat treatment at 80 ° C. for 30 minutes is performed on the intermediate device. The low melting point material constituting the low melting point material layer 18 is melted into a liquid by this heat treatment. The low-melting-point material that has become liquid can be embedded when conductive foreign matter is mixed between the first electrode 12 and the second electrode 16 (step S6).

Next, leave the intermediate device at room temperature (about room temperature). Thereby, the low melting point material is solidified in a state where the conductive foreign matter is embedded. Since the conductive foreign matter is covered with a low-melting-point material that is an insulator and does not function as a current leak path, current leak can be prevented in advance. Through the above steps, the organic EL device is completed (step S7).

As described above, in the method of manufacturing the organic EL device according to this example, the current leakage between the first and second electrodes is prevented in advance by performing the heat treatment after forming each component of the organic EL device. ing. Such heat treatment can be performed on all products regardless of the presence or absence of conductive foreign matter. In the heating process, batch processing of a large number of products is relatively easy, so productivity can be improved by making all products subject to heat treatment without checking the presence or absence of conductive foreign matter in the inspection process. It is possible to improve.

FIG. 5 is a flow chart of the manufacturing process of the organic EL device according to the embodiment of the present invention including the repair process of the short circuit part by the above-described second repair method. The process of forming each component of the organic EL device (steps S11 to S15) is the same as the above-described steps S1 to S5, and the description thereof is omitted.

After each component of the organic EL device 1 is formed, an inspection is performed to confirm the presence or absence of a short circuit between the first and second electrodes. And when it is confirmed that the short circuit has arisen, the short circuit location is specified. The identification of the short-circuit location can be realized by using, for example, an image recognition technique (step S16).

Next, the intermediate device obtained through steps S11 to S15 is heated. The heating temperature is set to be not less than the melting point of the low melting point material constituting the low melting point material layer 18 and not more than the glass transition temperature Tg of each material constituting the organic functional layer 14. For the heat treatment, a hot plate, a constant temperature layer, a belt furnace, or the like can be used. By performing such heat treatment, the low melting point material constituting the low melting point material layer 18 is melted to become a liquid. While the intermediate device is heated at the heating temperature, the laser beam is irradiated to the short-circuit portion specified in step S16. The laser beam is irradiated from the substrate 10 side with power that melts and evaporates the short-circuited portion. The metal or the like that forms the short circuit part absorbs the laser beam and generates heat to melt and evaporate. At this time, since the low melting point material layer 18 is melted by heating, the second electrode 16 is located upward (on the low melting point material layer side) as shown in FIG. Can be broken and deformed to open toward The short-circuit portion is removed by melting and evaporation together with the second electrode 16 by laser irradiation. The defective portion of the organic functional layer 14 from which the short-circuit portion has been removed is impregnated with a liquid low-melting-point material (step S17). In the above description, the laser irradiation is performed while heating the intermediate device. However, the laser irradiation can be performed independently. Also in this case, since the low melting point material layer 18 is heated and melted by laser irradiation, the short-circuit portion can be removed in the same manner as in the case with heat treatment.

Next, leave the intermediate device at room temperature (about room temperature). The low-melting-point material constituting the low-melting-point material layer 18 is solidified in a state where the fracture portion of the second electrode 16 is embedded. The defective portion of the organic functional layer 14 is filled with a low-melting material in a solid state. The organic EL device is completed through the above steps.

It should be noted that after step S17, it is checked whether or not the short circuit between the first and second electrodes has been resolved. If it is confirmed that the short circuit has not been resolved, the process of step S17 is repeated. It is good.

FIG. 6 is a manufacturing process flow chart of the organic EL device according to the embodiment of the present invention including the repair process of the short-circuit portion by the second repair method described above. Since the steps of forming each component of the organic EL device (steps S21 to S25) are the same as steps S1 to S5 described above, the description thereof is omitted.

After each component of the organic EL device 1 is formed, an inspection is performed to confirm the presence or absence of a short circuit between the first and second electrodes. And when it is confirmed that the short circuit has arisen, the short circuit location is specified. The identification of the short-circuited location can be realized by using, for example, an image recognition technique (step S26).

Next, the intermediate device obtained through steps S21 to S25 is heated. The heating temperature is set to be not less than the melting point of the low melting point material constituting the low melting point material layer 18 and not more than the glass transition temperature Tg of each material constituting the organic functional layer 14. For the heat treatment, a hot plate, a constant temperature layer, a belt furnace, or the like can be used. By performing such heat treatment, the low melting point material constituting the low melting point material layer 18 is melted to become a liquid. While heating the intermediate device at the above heating temperature, electric power is applied between the first and second electrodes so that a current flows through the short-circuited part specified in step S26. The applied power is set to a power at which the short circuit part can be melted and evaporated. At this time, since the low melting point material layer 18 is melted by heating, the second electrode 16 is located upward (on the low melting point material layer side) as shown in FIG. Can be broken and deformed to open toward The short-circuit portion is removed by melting and evaporation together with the second electrode 16 by applying electric power. The defective portion of the organic functional layer 14 from which the short-circuit portion has been removed is impregnated with a liquid low melting point material (step S27). In the above description, the power application is performed while heating the intermediate device. However, the power application can be performed independently. Also in this case, since the low melting point material layer 18 is heated and melted by application of electric power, it is possible to remove the short-circuit portion in the same manner as when heat treatment is involved.

In addition, after step S27, an inspection is performed to determine whether or not the short circuit between the first and second electrodes has been eliminated. If it is confirmed that the short circuit has not been eliminated, the process of step S27 is repeated. It is good.

As is clear from the above description, the organic EL device 1 according to the embodiment of the present invention is an organic that exhibits a solid state at room temperature between the second electrode 16 and the sealing layer 20 and constitutes an organic functional layer. A low melting point material layer 18 made of an insulator having a melting point lower than the glass transition temperature of the material is interposed. Since the organic EL device 1 has a solid sealing structure, the organic EL device 1 can be reduced in thickness as compared with a device having a hollow sealing structure, and high heat dissipation can be obtained.

Moreover, when a foreign material mixes between the 1st electrode 12 and the 2nd electrode 16, the low melting-point material layer 18 is comprised by heating the organic EL device 1 and melting the low-melting-point material layer 18. Foreign materials can be embedded with an insulator. As a result, it is possible to prevent the occurrence of current leakage due to foreign matter contamination. According to such a method for repairing a short-circuit portion, since the repair of the short-circuit portion is completed only by heat treatment, the number of steps in the repair process of the short-circuit portion can be significantly reduced as compared with the conventional method.

Further, by heating the organic EL device 1 to melt the low melting point material layer 18, the second electrode 16 can be ruptured so as to open upward (low melting point material layer side). Even in the stop structure, it is possible to remove the short-circuit portion by laser irradiation, power application, or the like. That is, since the impact due to the breakage of the second electrode 16 is absorbed by the liquid low-melting-point material layer 18, the sealing layer 20 can be prevented from being broken. Further, since the low melting point material layer 18 is in a solid state at room temperature, the low melting point material layer 18 is solidified to maintain the state after the repair of the short-circuit portion. Therefore, recurrence of current leak can be prevented. Thus, according to the organic EL device 1 according to the present embodiment, it is possible to easily and effectively repair the short circuit portion in the organic EL device having the solid sealing structure.

FIG. 7 is a cross-sectional view showing a configuration of an organic EL device 2 according to Example 2 of the present invention. The organic EL device 2 is different from the organic EL device 1 according to Example 1 in which sealing is performed with a thin film in that a sealing plate 22 that is a plate material is used as a sealing member. That is, on the substrate 10, a laminated body including the first electrode 12, the organic functional layer 14, and the second electrode 16 is provided, and a low melting point material layer 18 is provided so as to cover the laminated body. The material and forming method of each layer are the same as those of the organic EL device 1 described above. A sealing plate 22 is provided on the substrate 10 via an adhesive 24. The adhesive 24 is made of, for example, a thermosetting or ultraviolet curable silicone resin. The sealing plate 22 is a plate material such as a glass plate, a plastic plate, or a metal plate. Even in such a device using a plate-shaped sealing member, it is possible to repair the short-circuit portion as in the case of the organic EL device 1 having the inorganic sealing film described above. A sealing layer made of a thin film of an inorganic material may be further provided between the sealing plate 22 and the low melting point material layer 18.

FIG. 8 is a cross-sectional view showing the configuration of the organic EL device 3 according to Example 3 of the present invention. The organic EL device 3 is different from the organic EL device 1 according to Example 1 described above in that the solid sealing structure has a hollow sealing structure. That is, on the substrate 10, a laminated body including the first electrode 12, the organic functional layer 14, and the second electrode 16 is provided, and a low melting point material layer 18 is provided so as to cover the laminated body. The material and forming method of each layer are the same as those of the organic EL device 1 described above. On the substrate 10, a metal can 26 is provided that seals a laminate including the first electrode 12, the organic functional layer 14, the second electrode 16, and the low-melting-point material layer through a gap. That is, the hollow portion 40 extends above the low melting point material layer 18. The metal can 26 is bonded to the substrate 10 by an adhesive 28 made of an ultraviolet curable epoxy resin or the like. In the hollow portion 40, an adsorption drying agent made of BaO or CaO may be provided. Even in the device having such a hollow sealing structure, it is possible to repair the short-circuit portion as in the case of the organic EL device 1 having the solid sealing structure. By applying the present invention to a device having a hollow sealing structure, a foreign material mixed between the first electrode 12 and the second electrode 16 or a fracture portion of the second electrode caused by laser irradiation or the like can be used as a low melting point material layer. Therefore, it is possible to ensure the prevention of recurrence of current leakage.

FIG. 9 is a cross-sectional view illustrating a configuration of an organic EL device 4 according to Example 4 of the invention. The organic EL device 4 is different from the organic EL device 1 according to Example 1 described above in that a cover layer 50 is provided between the second electrode 16 and the low melting point material layer 18. The cover layer 50 covers the upper surface and the side surface of the laminate including the first electrode 12, the organic functional layer 14, and the second electrode 16. If the cover layer 50 is not present, a portion where the low melting point material layer 18 and the organic functional layer 14 are in direct contact may be formed depending on the pattern of the second electrode 16. Paraffin and tri-p-tolylamine exemplified above as constituent materials of the low-melting-point material layer 18 are organic materials, and thus have a property of being mixed with the organic materials constituting the organic functional layer 14. For this reason, when the low melting point material layer 18 and the organic functional layer 14 are in direct contact, the organic functional layer 14 is dissolved, and as a result, the second electrode 16 may be peeled off from the organic functional layer 14. The cover layer 50 covers the second electrode 16, and the low melting point material layer 18 and the organic functional layer 14 are not in direct contact with each other in the absence region of the second electrode 16. Is intervening. Thereby, peeling of the 2nd electrode 16 is prevented. The cover layer 50 is made of an inorganic material such as MoO ₃ , Al ₂ O ₃ , SiO ₂ , MgF ₂ , or AlF, and is formed using a sputtering method or the like. The cover layer 50 is formed with a thickness that can be broken together with the second electrode 16 by laser irradiation for repairing the short-circuit portion. The sealing layer 20 is provided so as to cover the stacked body including the cover layer 50.

<Other candidate materials for low melting point material layer>
In addition to paraffin and tri-p-tolylamine, some examples of other suitable materials constituting the low melting point material layer 18 are given. Since paraffin and tri-p-tolylamine exemplified above as constituent materials of the low melting point material layer 18 are organic materials, the organic material 14 is dissolved and the second electrode 16 may be peeled off from the organic functional layer 14. There is. Accordingly, the material constituting the low melting point material layer 18 is preferably a material that is difficult to mix with the organic functional layer 14 and does not dissolve the organic functional layer 14 from the viewpoint of preventing electrode peeling. Examples of such a material include a compound containing or combined with a chain saturated fluorocarbon whose general formula can be represented by C _n F _{2n + 2} . Hereinafter, such a compound will be referred to as a fluorinated alkane derivative.

FIG. 10 shows a specific example of a fluorinated alkane derivative suitable as a material for the low melting point material layer 18. 2- (Henicosafluorodecyl) ethyl acrylate (C ₁₅ H ₇ F ₂₁ O ₂ , melting point: 48-53 ° C.), heneicosafluorodecyl iodide (C ₁₀ F ₂₁ I, melting point: 65-67 ° C.) , Henicosafluoroundecanoic acid (C ₁₁ HF ₂₁ O ₂ , melting point: 96-101 ° C.), 1,1,1,2,2,3,3,4,4,5,5,6,6,7, 7,8,8,9,9,9,10,10-Henicosafluorodecane (C ₁₀ HF ₂₁ , melting point: 31 ° C.), 4,4,5,5,6,6,7,7,8, 8,9,9,10,10,11,11,12,12,13,13,13-Henicosafluoro-1,2-epoxytridecane (C ₁₃ H ₅ F ₂₁ O, melting point: 61-62 ° C.), etc. Can be suitably used as the material of the low-melting-point material layer 18. These fluorinated alkane derivatives are materials that exhibit liquid repellency with respect to the organic functional layer 14 in a liquid state, and the organic functional layer 14 is not dissolved by these materials, and thus prevents the second electrode 16 from being peeled off. Can do. Further, these materials are in a solid state at room temperature (about room temperature, for example, around 25 ° C.) and have a melting point lower than the glass transition temperature Tg of each material constituting the organic functional layer 14. Repair processing of the short-circuited portion is possible.

In the case of forming the low melting point material layer 18 using these fluorinated alkane derivatives, as in the case of using paraffin, a method of coating the fluorinated alkane derivative as a liquid by heating, or forming a powdered fluorinated alkane derivative is used. After spraying on the two electrodes 16, a method of forming a film by heating the substrate 10 to melt the powdered fluorinated alkane derivative can be used.

<High temperature durability evaluation>
As a specific example of the fluorinated alkane derivative, an organic EL device having a solid sealing structure having the low-melting-point material layer 18 made of 2- (henicosfluorodecyl) ethyl acrylate described above was manufactured and subjected to a high temperature durability test. Specifically, after four samples of organic EL devices having different configurations of the second electrode (cathode) 16 are left in an atmosphere at 100 ° C. for 50 hours, the presence or absence of peeling of the second electrode 16, electrical characteristics, and The light emission characteristics were evaluated. The configuration of the second electrode 16 includes an Al single layer, an Ag single layer, a stack of Ag and Al (the side in contact with the organic functional layer is Ag), and a stack of Al and Ag (organic functional layer). There are four types of Al) on the side in contact with. FIG. 11 shows the evaluation results of each sample.

After leaving it in an atmosphere of 100 ° C. for 50 hours, no electrode peeling was confirmed in any of the electrode configurations. The electrical characteristics were good with no change from the initial stage before leaving at high temperature in any electrode configuration. Luminous spots (brightness unevenness) were confirmed in the case where the second electrode 16 was composed of an Ag single layer, and the light emission characteristics were good for the other electrode configurations.

From the above results, the use of 2- (henikosafluorodecyl) ethyl acrylate as the material of the low-melting-point material layer 18 can prevent the second electrode 16 from being peeled off and is effective in improving the reliability. confirmed. In addition, in what comprised the 2nd electrode by Ag single layer, it was thought that the luminance spot was originated in the adhesive force of Ag and the organic functional layer 14 being small. However, it has been confirmed that the luminance unevenness is eliminated regardless of the stacking order when the second electrode has a stacked structure of Ag and Al. Since Ag has a relatively high reflectance, it is effective for improving the light extraction efficiency of the organic EL device. By making the second electrode a laminated structure of Ag and Al, it is possible to improve the light extraction efficiency of the organic EL device while ensuring high adhesion to the organic functional layer 14. Examples of the electrode material having high adhesion to the organic functional layer 14 include easily oxidized Al and MgAg alloy.

1-4 Organic EL devices 10 Substrate 12 First electrode 14 Organic functional layer 16 Second electrode 18 Low melting point material layer 20 Sealing layer 22 Sealing plate 26 Metal can 30 Conductive foreign matter 31 Short-circuited part 50 Cover layer

Claims

An organic EL structure including a first electrode provided on a substrate, an organic functional layer including at least one layer provided on the first electrode, and a second electrode provided on the organic functional layer When,
A low-melting-point material layer that is provided on the second electrode and is made of an insulator that exhibits a solid state at room temperature and has a melting point lower than the glass transition temperature of the organic material constituting the organic functional layer;
A sealing layer that seals the laminate composed of the organic EL structure and the low-melting-point material layer,
The low-melting-point material layer is made of a compound containing or combined with a chain saturated fluorine represented by a general formula of C n F 2n + 2 .
2. The organic electroluminescence device according to claim 1, wherein the low-melting-point material layer contains 2- (henicosafluorodecyl) ethyl acrylate.
The organic electroluminescence device according to claim 1, further comprising a cover layer made of an inorganic material interposed between the organic EL structure and the low-melting-point material layer.
An organic EL structure including a first electrode provided on a substrate, an organic functional layer including at least one layer provided on the first electrode, and a second electrode provided on the organic functional layer When,
A cover layer made of an inorganic material covering the organic EL structure;
A low-melting-point material layer made of an insulator provided on the cover layer and having a melting point lower than a glass transition temperature of an organic material that exhibits a solid state at room temperature and constitutes the organic functional layer;
An organic electroluminescent device comprising: a sealing layer that seals a laminate including the organic EL structure, the cover layer, and the low-melting-point material layer.
The organic electroluminescence device according to claim 4, wherein the low melting point material layer includes paraffin.
The organic electroluminescence device according to claim 4, wherein the low melting point material layer contains tri-p-tolylamine.
The organic electroluminescence device according to any one of claims 1 to 6, wherein the second electrode is configured by laminating Al and Ag.
The organic electroluminescence device according to any one of claims 1 to 6, wherein the sealing layer includes a thin film made of an inorganic material.
The organic electroluminescent device according to any one of claims 1 to 6, wherein the sealing layer includes a plate material made of metal or glass.
A method for producing an organic electroluminescent device, comprising:
Forming a first electrode on a substrate;
Forming an organic functional layer comprising at least one layer on the first electrode;
Forming a second electrode on the organic functional layer;
Forming a low melting point material layer made of an insulator that exhibits a solid state at room temperature on the second electrode and has a melting point lower than the glass transition temperature of the organic material constituting the organic functional layer;
Forming an intermediate device by forming a sealing layer that seals the laminate composed of the first electrode, the organic functional layer, the second electrode, and the low-melting-point material layer;
A heating step of heating the intermediate device at a temperature higher than the melting point of the low-melting-point material constituting the low-melting-point material layer.
A method for producing an organic electroluminescent device, comprising:
Forming a first electrode on a substrate;
Forming an organic functional layer comprising at least one layer on the first electrode;
Forming a second electrode on the organic functional layer;
Forming a low melting point material layer made of an insulator that exhibits a solid state at room temperature on the second electrode and has a melting point lower than the glass transition temperature of the organic material constituting the organic functional layer;
Forming an intermediate device by forming a sealing layer that seals the laminate composed of the first electrode, the organic functional layer, the second electrode, and the low-melting-point material layer;
Identifying a short-circuit location between the first and second electrodes;
And a step of irradiating the short-circuit portion with a laser to remove the short-circuit portion.
In the step of irradiating the laser to the short-circuited portion, the intermediate device is heated at a temperature higher than the melting point of the low-melting-point material constituting the low-melting-point material layer in parallel with the laser irradiation to the short-circuited portion. The manufacturing method according to claim 11.
A method for producing an organic electroluminescent device, comprising:
Forming a first electrode on a substrate;
Forming an organic functional layer comprising at least one layer on the first electrode;
Forming a second electrode on the organic functional layer;
Forming a low melting point material layer made of an insulator that exhibits a solid state at room temperature on the second electrode and has a melting point lower than the glass transition temperature of the organic material constituting the organic functional layer;
Forming an intermediate device by forming a sealing layer that seals the laminate composed of the first electrode, the organic functional layer, the second electrode, and the low-melting-point material layer;
Identifying a short-circuit location between the first and second electrodes;
And applying a power between the first and second electrodes to remove the short-circuit portion in order to pass a current through the short-circuit portion.
In the step of applying power between the first and second electrodes, the melting point of the low-melting-point material constituting the low-melting-point material layer in parallel with the application of power between the first and second electrodes. The manufacturing method according to claim 13, wherein heating is performed at a higher temperature.