WO2007029586A1

WO2007029586A1 - Method for manufacturing organic electroluminescent device

Info

Publication number: WO2007029586A1
Application number: PCT/JP2006/317168
Authority: WO
Inventors: Kazuo Genda
Original assignee: Konica Minolta Holdings, Inc.
Priority date: 2005-09-08
Filing date: 2006-08-31
Publication date: 2007-03-15
Also published as: JPWO2007029586A1

Abstract

Disclosed is a method for manufacturing an organic EL device wherein production load during formation of a protective film is decreased without lowering the protective resistance to moisture or oxygen. Specifically disclosed is a method for manufacturing an organic electroluminescent device wherein a protective film is formed over an organic electroluminescent device which is formed on a substrate. In this method, the step for forming the protective film is composed of a step (103) for forming a first protective film in a vacuum environment, and a step (104) for forming a second protective film in an atmospheric pressure environment.

Description

Specification

Method of manufacturing organic electoluminescence device

Technical field

The present invention relates to a method for manufacturing an organic EL element in which a protective film is formed on an organic electoluminescence (EL) element.

Background art

In recent years, organic EL elements have attracted attention as self-luminous elements. An organic EL element is an element that emits light when an electric current is supplied between electrodes, in which a light-emitting layer having a thin film strength of an organic compound is sandwiched between electrodes on a substrate such as glass.

[0003] Organic EL elements are easily deteriorated by oxygen and moisture, and their presence shortens the product life. Therefore, as a protective film (also called a barrier film) immediately after forming the organic EL element from the viewpoint of reliability, It is desirable to cover it with a stable protective film against oxygen and water to completely block it from the outside air. Examples of the protective film include a metal nitride film and an oxide film. In the case of a so-called top emission configuration in which the light emission of the organic EL element is extracted in a direction that transmits the protective film force, a protective film with high transparency is required.

On the other hand, the protective film is formed by using a thin film manufacturing method such as an electron beam method, a sputtering method, a plasma CVD method, or an ion plating method. These thin film forming methods can form a film relatively easily even in a high-melting-point material under a vacuum environment.

[0005] As a conventional protective film forming technique, a technique using a facing target type sputtering apparatus has been disclosed (for example, refer to Patent Document 1). However, in these conventional thin film deposition methods, the protective film has a single-layer structure, so that the effect on moisture permeation in a high-temperature and high-humidity environment is insufficient, and the surface of the organic EL element is At the protrusions and steps, cracks were generated in the protective film, and the resistance to moisture and oxygen was insufficient.

[0006] Thus, a technique is disclosed in which a plurality of inorganic protective films sandwiching a thermosetting resin are laminated to form a protective film (see, for example, Patent Document 2). Lamination of the protective film improves resistance to moisture and oxygen, and the thermosetting resin reduces the occurrence of cracks due to steps. [0007] However, with this protective film configuration, a plurality of protective films must be formed in a vacuum environment in the manufacturing process, and the cost of the manufacturing apparatus is lower than that of a single-layer protective film forming process. Rising was an issue.

[0008] On the other hand, as a protective film, a technique is disclosed in which a sheet-like sealing member in which a protective film is formed on an organic EL element is bonded (for example, see Patent Document 3).

[0009] However, it is difficult to realize the working environment of the technique for holding the organic EL element by vacuum suction and the technique for applying the resin material by the syringe in a vacuum environment. For this reason, deterioration due to moisture and oxygen of the organic EL element before sealing in an atmospheric pressure environment has become a problem.

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-332567

Patent Document 2: Japanese Patent Application Laid-Open No. 2004-119138

Patent Document 3: Japanese Patent Laid-Open No. 2005-4063

Disclosure of the invention

Problems to be solved by the invention

[0010] The present invention has been made in view of the above problems, and an object of the present invention is an organic EL element in which the manufacturing load at the time of forming a protective film without reducing the protection resistance against moisture and oxygen is reduced. It is to provide a manufacturing method.

Means for solving the problem

The above object of the present invention has been achieved by the following constitution.

[0012] 1. A first protective film was formed in a vacuum environment in accordance with a manufacturing method of an organic electoluminescence element that forms a protective film on an organic electroluminescence element formed on a substrate. Then, the manufacturing method of the organic electroluminescent luminescence element characterized by forming a 2nd protective film in atmospheric pressure environment.

[0013] 2. The organic electo according to 1 above, wherein the first protective film is formed by using an electron beam method, a sputtering method, a plasma CVD method, or an ion plating method. A method for manufacturing an oral luminescence element.

[0014] 3. The method of manufacturing an organic electoluminescence device according to the above 1 or 2, wherein the first protective film is either silicon nitride oxide or silicon nitride. [0015] 4. The formation of the second protective film is carried out under an atmospheric pressure environment and an environment with a dew point temperature of 10 ° C or lower. The manufacturing method of the organic electoluminous element of description.

[0016] 5. The method for producing an organic-electric-luminescence device according to any one of 1 to 4, wherein the second protective film is a resin film.

[0017] 6. A protective film is formed in advance on the resin film.

6. The method for producing an organic electoluminescence device according to any one of 5 above.

[0018] 7. The force described in any one of 1 to 6 above, wherein an intermediate layer is provided between the first protective film and the second protective film under an atmospheric pressure environment. Manufacturing method of organic electroluminescence device.

The invention's effect

[0019] According to the present invention, it is possible to provide a method for manufacturing an organic EL element in which the manufacturing load at the time of forming a protective film is reduced without reducing the protection resistance against moisture and oxygen.

Brief Description of Drawings

FIG. 1 is a schematic diagram showing a configuration of an organic EL element 10.

FIG. 2 is a block diagram showing a manufacturing process when forming a protective film.

FIG. 3 is a schematic diagram of a magnetron sputtering apparatus for forming a first protective film.

FIG. 4 is a schematic view of a laminating apparatus for forming a second protective film.

FIG. 5 is a schematic cross-sectional view of an organic EL device sealed with a glass material sealing material.

Explanation of symbols

[0021] 10 Organic EL device

11 Board

12 Anode

13 Organic layer

14 Cathode

20 Vacuum chamber

21 Exhaust vent 30 targets

31 Power Sword

32 Magnet

50 power supply

50a matching unit

51 Pasting means

52 Laminating means

53 Cutting means

54 Curing means

55 Sealing film

60 Transport means

100 magnetron sputtering equipment

200 Laminating equipment

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode for carrying out the present invention will be described in detail.

[0023] An example showing an embodiment of the present invention will be described below with reference to the drawings.

First, the organic EL element will be described below.

FIG. 1 is a schematic diagram showing a configuration of the organic EL element 10.

In the figure, an organic EL element 10 is an element in which an anode 12, an organic layer 13, and a cathode 14 are stacked on a substrate 11.

[0027] The anode 12 is a transparent electrode made of a conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), gold, tin oxide, and zinc oxide having a work function of 4 eV or more and a transmittance of 40% or more. is there.

The organic layer 13 is composed of a single layer or a plurality of layers containing an organic compound or complex of several nm to several μm including the light emitting layer. For example, it is typically an element composed of three layers, such as a hole transport layer in contact with the anode, a light emitting layer containing a light emitting material, and an electron transport layer in contact with the cathode, a lithium fluoride layer, an inorganic metal salt layer, Alternatively, a layer containing them may be arranged at an arbitrary position. [0029] The cathode 14 is a reflective electrode made of a metal material having a work function of less than 4 eV and a reflectivity of 60% or more, such as ananolium, sodium, lithium, magnesium, silver, and calcium.

[0030] The substrate 11 may be a substrate for a solid substrate such as glass or quartz, or polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether sulphone (PES), polyether as the base material. Imide, polyether ether ketone, polyphenylene sulfide

, Base material for flexible substrates such as polyarylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC), cellulose acetate propionate (CAP)

[0031] The organic EL element 10 in the present invention utilizes the excitation energy generated by the combination of electrons and holes in the organic layer 13 due to the current supplied from the outside via the anode 12 and the cathode 14 in the organic layer 13. In the device that emits light, light from the organic layer 13 is extracted through the anode 12 in this case. Examples of light emission that uses excitation energy include fluorescence that uses singlet excitation energy for light emission, or phosphorescence that uses triplet excitation energy for light emission.

[0032] In particular, phosphorescence is desirable light emission as a light source because triplet excitons contribute to light emission, so that high light emission efficiency is obtained compared to fluorescence.

Light emission from the light emitting layer of the organic EL element 10 is emitted through the anode 12 and the substrate 11 (bottom emission and remission), but a thin film cathode material and a highly transparent anode material are used. A top emission configuration in which light is emitted from a laminated substantially transparent cathode may be used.

Next, a manufacturing process for forming a protective film on these organic EL elements will be described.

FIG. 2 is a block diagram showing a manufacturing process when forming the protective film.

[0036] In the method of manufacturing an organic EL element of the present invention, the substrate cleaned in the cleaning step 101 is formed in an organic EL element forming step 102 in a vacuum environment. After the organic EL element is formed, In the first protective film forming step 103, the first protective film is formed in the same vacuum environment. Thereafter, the process proceeds to the second protective film forming step 104 from the vacuum environment, and the second protective film is formed under the atmospheric pressure environment.

[0037] Details of each manufacturing process will be described below. [0038] In the cleaning step 101, the substrate on which the anode has been patterned in advance is wet-cleaned by ultrasonic waves using various cleaning liquids and rinse agents, UV irradiation, oxygen plasma cleaning under a predetermined pressure, etc. This is a step of performing dry cleaning by the method. The substrate is preferably a matrix of TFT in advance.

[0039] The cleaned substrate is then transferred to the organic EL element forming step 102. Here, in a vacuum environment at a pressure of 10 ⁻³ Pa or lower, an organic EL element is formed by laminating an organic layer and a negative electrode on the anode of the substrate by vapor deposition.

[0040] The substrate on which the organic EL element is formed is transferred to the first protective film forming step 103, and 10-

Well-known electron beam method and sputtering method in a vacuum environment at a pressure of Pa or less

Then, the first protective film is formed so as to cover the organic EL element by a thin film fabrication method such as plasma CVD method or ion plating method.

[0041] The substrate on which the first protective film is formed is transferred to the second protective film forming step 104. The second protective film formation process is controlled in a dry environment with a dew point temperature of 10 ° C or lower in addition to the atmospheric pressure environment of approximately tens of thousands Pa to several tens of thousands Pa from the vacuum environment described above. The lower limit of the dew point temperature according to the invention is preferably -30 ° C.

[0042] Since the first protective film is already used as a protective film, sufficient protection resistance against moisture is secured in this dry environment, and the second protective film is formed by the second protective film forming step 104. The environment to be formed need not be a vacuum environment.

Next, the protection forming apparatus in the organic EL manufacturing method of the present invention will be described below.

[0044] In the first protective film forming step of the present invention, the protective film forming method for forming the first protective film may be an electron beam method, a sputtering method, a plasma CVD method, or an ion plating method. Use either of them.

[0045] All of these methods are methods capable of forming a thin film under vacuum. By using these methods, the influence of water and oxygen is reduced on the organic EL element formed by the vacuum evaporation method. The protective film can be formed in a vacuum environment (under reduced pressure).

[0046] For example, the electron beam method (vacuum evaporation method) is a material for forming a thin film under vacuum. The film is irradiated with an electron beam, heated and evaporated, and the evaporated material is deposited (deposited) on a substrate to form a thin film. There are special features such as high deposition rate and little damage to the substrate.

[0047] In the plasma CVD method, RF gas (for example, 13.56MHz) is used to excite a gas material introduced into a certain vacuum environment to generate plasma, which is purified by reaction and decomposition of the material molecules on the substrate. The thin film forming component is deposited to form a thin film.

[0048] The ion plating method is a method for producing a thin film by evaporating a material desired to be a thin film, ionizing the material by radio frequency (RF), and depositing it on a substrate.

[0049] In addition, in the sputtering method, a material (target material) to be formed into a thin film is collided with plasma, ions, or the like generated by plasma discharge, so that the material is splashed (sputtering). This splashed material is deposited on a substrate to produce a thin film.

[0050] The sputtering method has fewer target material constraints than the plasma CVD method, ion plating method, etc., which require introduction of the raw materials necessary for thin film formation, as well as the electron beam method, etc. Of these, a sputtering method is a particularly preferable method in the present invention because a thin film can be formed relatively easily even with a high melting point material.

Hereinafter, a magnetron sputtering apparatus will be described as the first protective film forming step 103.

FIG. 3 is a schematic diagram of a sputtering apparatus for forming the first protective film.

[0053] The magnetron sputtering apparatus 100 includes a vacuum chamber 20, an exhaust port 21, a target 30, and a force sword 31.

, Magnet 32, Substrate 11, Power supply 500, Matching unit 510, etc.

The vacuum tank 20 is a tank that provides a decompressed space that is blocked from outside air, and the inside of the tank is decompressed by a vacuum pump (not shown) connected to the exhaust port 21.

[0055] The target 30 is the same material as the constituent material of the protective film formed on the organic EL element, or the same material as the constituent material by reaction with the sputtering gas. The protective film is a film containing at least one kind of metal oxide film, nitride film, metal thin film, and diamond-like carbon film, and is a thin film having a thickness of 50 nm to 50 μm.

[0056] The target 30 is connected to the force sword 31. When a voltage is applied from the power source 50 via the force sword 31, and a sputtering gas is introduced from the gas supply port 33, the target 30 has a true gas pressure. In an empty or depressurized environment, plasma is generated in the space inside the target 30 to perform the shooting.

[0057] The magnet 32 is, for example, a Fe_Nd_B or Sm_Co based rare earth sintered magnet, a Ba based or Sr based sintered ferrite magnet, a bonded magnet such as a ferrite based magnet, a forged magnet such as an alnico based permanent magnet, or an electromagnet. And a magnetic field generating means for generating a predetermined magnetic field. The magnet 32 may be arranged at a position where a predetermined magnetic field is generated in the plasma generation space. However, as shown in the figure, the arrangement of the magnet 32 on the surface opposite to the inner surface of the target 30 where the sputtering is performed has a magnetic field strength. From the viewpoint of storage efficiency in the vacuum chamber 20, this is a preferable configuration.

[0058] Further, a cooling means (not shown) may be provided so as to be in contact with the magnet 32 to reduce the magnet 32 from being heated to a high temperature due to sputtering.

The substrate 11 is a substrate on which the target 30 is sputtered and a protective film is formed thereon. The substrate 11 is a substrate for the organic EL element 10 or the like described above. In order to improve the uniformity of the protective film thickness distribution, it is preferable to rotate the substrate 11 during sputtering by the rotation support member 42. However, the substrate 11 is not limited to the substrate rotation, and the substrate 11 is fixedly supported without rotating. You may do it.

[0060] The power supply 50 is a power supply that applies a voltage to the target 30, and generates direct current, alternating current, or alternating current to which a direct current bias is applied depending on the conductivity of the material. When an AC voltage is applied, impedance matching with the target 30 is achieved by the matching unit 50a.

[0061] The matching unit is normally used as a set in an RF magnetron sputtering apparatus that applies an AC voltage when using a high frequency power source for plasma. The high frequency power output from the high frequency power source for plasma is This is a device that efficiently feeds into the chamber where the air is generated.

Next, the apparatus in the second protective film forming step 104 will be described below.

FIG. 4 is a schematic diagram of a laminating apparatus for forming a second protective film.

[0064] The laminating apparatus 200 includes a conveying means 50, an attaching means 51, a laminating means 52, a cutting means 53, a curing means 54, a sealing film 55, and the like.

The transport means 50 is a transport means for forming a second protective film on the organic EL element 10 on which the first protective film is formed by the first protective film forming means, using a laminating apparatus. Here, the force S that conveys a sheet of organic EL elements by a conveyor S, a continuous film-like mouth The substrate wound in a roll may be conveyed by a roller.

[0066] Affixing means 51 is a means for affixing an adhesive layer for forming a second protective film on the organic EL element. In FIG. 4, it is applied to the first protective film of the organic EL element 10 with a syringe. Adhesive that is cured by ultraviolet rays is attached.

[0067] As the sealing film, a thin resin film having flexibility, for example, a resin film such as polyethylene terephthalate, polyethylene naphthalate, polycarbonate, ethylene polyvinyl alcohol, ethylene butyl acetate, and ETFE is used. A laminated film may also be used.

[0068] Further, as the adhesive, for example, an ultraviolet curable resin such as an epoxy-based resin, an acrylic resin, and an acrylic urethane-based resin can be used. Further, a thermosetting resin may be used. The adhesive may be applied to the sealing portion using a commercially available dispenser or printing such as screen printing.

[0069] Not limited to this, an adhesive sheet as disclosed in Japanese Patent Application Laid-Open No. 2004-139977 may be attached to the sealing film.

The laminating means 52 is a means for laminating the sealing film 55 fed out by the long roller force onto the organic EL element 10. In the figure, the sealing film 55 is laminated on the organic EL element 10 by pressing and heating the upper and lower rollers.

The cutting means 53 is a means for cutting an excess portion of the sealing film 55 laminated on the organic EL element 10. In the figure, the sealing film is cut along the edge of the organic EL element 10 by a cutter. The cutting means is not limited to a cutter, and if a circular rotating cutter with vibration is used, cutting waste is good.

The curing means 54 is a means for curing the adhesive layer attached by the attaching means 51. Fig. 4 shows an example in which an ultraviolet curable resin is used as the adhesive layer, which is irradiated with a UV light source and cured by photoreaction.

[0073] In the manufacturing method of the present invention, since the first protective film is formed in advance, damage to the organic EL element due to moisture and oxygen is reduced in the step of forming the second protective film. Therefore, the work environment does not need to be in a vacuum environment.

Accordingly, the apparatus in the second protective film forming step for forming the second protective film is vacuumed. The cost of manufacturing equipment that does not need to be reduced is reduced. In addition, the process of forming the second protective film can be performed in an environment under atmospheric pressure, for example, repair work of a sheet failure that has occurred in the bonding process and maintenance work such as replacing the cutter used in the cutting process. Compared to working from a vacuum environment to an atmospheric pressure environment, work efficiency can be improved and process stop time can be shortened.

Example

[0075] Next, the present invention will be described more specifically, but the present invention is not limited thereto.

Hereinafter, specific conditions for forming the protective film will be described.

[0077] Example 1

First, as an example of a method for producing an organic EL element, production of an organic EL element having an anode / hole transport layer / light emitting layer / cathode force will be described.

[0078] << Production of Organic EL Element 1 >>: Present Invention

Installing a substrate of washed glass 100mm angle deposition vacuum chamber maintained under a vacuum environment at a pressure of vacuum degree of 10- ⁵ Pa. In the vapor deposition vacuum chamber, an anode was prepared by forming an anode material ITO by an electron beam method to a thickness of 100 OA. Next, _NPD, which is an organic EL device material, was vapor-deposited at a rate of 2 A / sec as a hole transport layer to form a thickness of 500 A. Next, Alq was deposited as a light emitting layer at a rate of 2AZ seconds to form a thickness of 600A. After forming these layers, the cathode material was formed by vapor-depositing aluminum, which is a cathode material, at a rate of 3 A / second so as to have a film thickness of 2 000 A. Thus, an organic EL device 1 was produced. .

[0079] [Chemical 1]

[0080] Next, the produced organic EL element 1 was transported to a sputtering apparatus which is a first protective film forming step in order to form a first protective film while maintaining a vacuum environment. The sputtering equipment shown in Fig. 2 was used.

[0081] Using silicon nitride (Si N) as a target material, a target is formed in a cylindrical shape,

3 4

The distance between the upper end of the cylindrical target and the substrate of the organic EL element was 7 cm. Using argon containing oxygen 2% by volume of the sputtering gas was a gas pressure 1. a 33 X 10- ² Pa.

[0082] The power source was an AC power source with a frequency of 13.56 MHz, and the film forming rate when the input power was 100 W was 1 A / second when monitored by a crystal resonator. Under these conditions, a protective film (also referred to as a barrier film) having a thickness of 5000 A was formed on the organic EL element 1 to produce an organic EL element 1 having a first protective film.

[0083] Next, the organic EL element 1 having the first protective film is transported from the vacuum environment to the second protective film forming step in the dry air atmospheric pressure environment with a dew point temperature of 10 ° C, A protective film was formed.

[0084] After applying 5516XNR made by Nagase Chemtech as an ultraviolet curable resin on the organic EL element by the laminating apparatus in the second protective film forming step, the sealing film was heated and pressure-bonded by a roller at 100 ° C. Laminated to EL element. The sealing film is a film that is made by bonding together the EVA film made by Pridestone (ethylene vinyl acetate thickness 0.4 mm) and the weather resistant resin made by Asahi Glass ETFE (aflex thickness 25 μm). It was.

[0085] After that, after cutting off the unnecessary portion of the sealing film, the laminate was completed by irradiating with a UV light source until the integrated irradiation energy became 6000mjZcm ² to produce the organic EL device 1 having the second protective film. did.

[0086] << Preparation of organic EL elements 1-12, >>: Comparative example

Installing a substrate of washed glass 100mm angle deposition vacuum chamber maintained under a vacuum environment at a pressure of vacuum degree of 10- ⁵ Pa. In the vapor deposition vacuum chamber, an anode was prepared by forming an anode material ITO by an electron beam method to a thickness of 100 OA.

[0087] Next, _NPD, which is an organic EL element material, was vapor-deposited at a rate of 2 AZ seconds as a hole transporting layer to form a thickness of 500A. Next, using Alq as the light-emitting layer

3 Vapor deposited at a rate of 2AZ seconds to form a thickness of 600A. After these layers are formed, a cathode material is formed thereon. An organic EL device was fabricated by forming a cathode by depositing aluminum at a rate of 3 A / second to a thickness of 2000 A.

[0088] As shown in the schematic cross-sectional view of FIG. 5, the fabricated organic EL element is covered with a glass material sealing material 15 so that the organic EL material is shielded from the outside air in an atmosphere of dry nitrogen. A comparative sample was prepared by adhering the sealing material to the substrate with an adhesive 16 of UV curable resin and sealing it.

[0089] << Evaluation results >>

Each of the sealed organic EL device samples thus produced was driven at a constant current of ^2.5 mA / cm ² to evaluate each sample.

[0090] The organic EL device 11 of the present invention immediately after fabrication has the same external extraction efficiency and drive voltage as compared with the organic EL device 12 of the comparative example, and is organic when forming the protective film. Show less damage to the EL element.

[0091] The external extraction efficiency was measured by using a spectral radiance meter CS-1000 (manufactured by Konica Minolta) to measure the light emission when each sample was driven at a constant current of ^2.5 mA / cm ² to emit light. For each, the external extraction efficiency (%) was calculated and compared. As for the driving voltage, we compared the voltages when driving at a constant current of ^2.5 mA / cm2.

[0092] Further, for each of the fabricated sealed elements, after being stored for 500 hours at a high temperature and high humidity of 60 ° C and 90% RH, it was driven at a constant current of ^2.5 mA / cm ² , As described above, the external extraction efficiency, the driving voltage, and the power of comparing the number of non-light-emitting points (dark spots) that can be visually confirmed in the range of 2 mm × 2 mm square between each sampnole are as follows. Compared with the organic EL device 1-2 of the comparative example (organic EL device sealed with glass), the same storage characteristics were confirmed for the external extraction efficiency, drive voltage, and dark spot.

Claims

The scope of the claims

[1] In the method for manufacturing an organic electroluminescent element in which a protective film is formed on an organic electroluminescent element formed on a substrate, the second protective film is formed after the first protective film is formed in a vacuum environment. Is formed under an atmospheric pressure environment, and a method for producing an organic electroluminescent element.

[2] The organic electrification opening according to claim 1, wherein the first protective film is formed using any one of an electron beam method, a sputtering method, a plasma CVD method, and an ion plating method. Manufacturing method of luminescence element.

[3] The manufacturing of the organic electroluminescent element according to claim 1 or 2, wherein the first protective film is either silicon nitride oxide or silicon nitride. Method.

[4] The formation of the second protective film is carried out under an atmospheric pressure environment and an environment with a dew point temperature of 10 ° C. or lower. The manufacturing method of the organic electoluminescence device of any one of 4.

[5] The method for producing an organic electoluminescence device according to any one of claims 1 to 4, wherein the second protective film is a resin film.

[6] The protective film is formed in advance on the resin film. The power of the organic electoluminescence device according to any one of claims 1 to 5, Production method.

[7] An intermediate layer is provided between the first protective film and the second protective film under an atmospheric pressure environment. The manufacturing method of the organic electoluminescence device of any one term.