JP6098090B2 - Method for manufacturing organic electroluminescence panel - Google Patents

Description

The present invention uses an organic EL element expected to be widely used as a flat panel display used in a portable terminal such as a television, a personal computer monitor, a cellular phone, a surface emitting light source, an illumination, a light emitting advertising body, and the like. the method for producing an organic electroluminescent panel.

An organic EL (Electro-Luminescence) element is expected as a flat panel display that replaces a cathode ray tube or a liquid crystal display because of advantages such as a wide viewing angle, a high response speed, and low power consumption.
An organic EL element has a structure in which an organic light emitting medium layer is sandwiched between two electrode layers (an anode layer and a cathode layer), at least one of which has translucency, and a voltage is applied between both electrodes. It is a self-luminous display element in which light is emitted from the organic light emitting medium layer when an electric current is passed. However, the organic EL element has a problem that it deteriorates due to the influence of moisture and oxygen in the atmosphere. For this reason, a sealing method (cap sealing) in which the organic EL element is covered with a metal can or glass cap containing a desiccant and shielded from the atmosphere is generally used.

However, cap sealing with the above-described hollow structure has disadvantages such as low mechanical strength, difficulty in increasing the size, and processing cost increases in the case of a glass cap. For this reason, solid sealing has been proposed in which a space between a flat sealing substrate and an element substrate on which an organic EL element is formed is filled with a resin.
In cap sealing, sealing performance is ensured by a desiccant attached inside a metal can or glass cap. On the other hand, in solid sealing, by forming an inorganic sealing layer on the organic EL element, deterioration of the EL element due to moisture entering from the outside is prevented. The properties required for the inorganic sealing layer include low moisture permeability, low film stress so as not to damage the organic EL element, pinholes in the inorganic sealing layer itself, and foreign matter on the organic EL element. In the case where the organic EL element is a top emission type, the transmittance is high.

In order to satisfy such requirements, attempts have been made to use silicon nitride or silicon oxynitride formed by plasma CVD (Chemical Vapor Deposition) as an inorganic sealing layer. Desired sealing performance can be obtained by the inorganic sealing layer formed by CVD. However, in order to obtain a desired sealing performance, it is generally necessary to form an inorganic sealing layer with a thickness of about 3 to 5 μm, which is not necessarily preferable from the viewpoint of productivity and cost.
As another method for blocking the moisture from the outside and preventing the deterioration of the organic EL element, a method of forming an inorganic sealing layer on the side surface of the organic EL panel has been proposed (see Patent Documents 1 and 2 below). ).

  FIG. 4 is a cross-sectional view illustrating a configuration example of an electroluminescent element (hereinafter appropriately referred to as an organic EL element 30) disclosed in Patent Document 1. The organic EL element 30 includes an element substrate 31, an organic electroluminescent layer 35, an organic filling layer 36, and a sealing substrate 37 in which a first electrode layer 32, an organic light emitting medium layer 33, and a second electrode layer 34 are sequentially stacked. It is described that it is provided. Further, it is described that the organic EL element 30 includes an inorganic sealing layer 38 formed so as to cover the side surface of the organic filling layer 36.

  In the organic EL element 30 of Patent Document 1, it is described that the intrusion of moisture from the side surface is suppressed by the inorganic sealing layer 38 formed so as to cover the side surface of the organic filling layer 36. In addition, in the cross section perpendicular to the element substrate 31, the inorganic sealing layer 38 has a bow-shaped surface that protrudes toward the organic filling layer 36, so that the stress on the inorganic sealing layer 38 accompanying the expansion of the organic filling layer 36 is exerted. It is described that the damage to the inorganic sealing layer 38 is suppressed by being dispersed.

  FIG. 5 is a cross-sectional view illustrating a configuration example of an organic EL device (hereinafter, appropriately referred to as an organic EL device 40) disclosed in Patent Document 2. The organic EL device 40 is formed so as to cover the element substrate 41, the organic EL element 42, the first sealing layer 43 covering the organic EL element 42, the organic filling layer 44 and the sealing substrate 45, and the side surface of the organic filling layer 44. It is described that the second sealing layer 46 is provided.

  In the organic EL device 40 of Patent Document 2, the first sealing layer 43 is formed on the organic EL element 42 using plasma CVD. Similarly to Patent Document 1, the second sealing layer 46 is formed on the side surface of the organic filling layer 44 by applying a polysilazane solution. Since the second sealing layer 46 is formed by a coating process, defects are relatively less likely to occur than the first sealing layer 43 formed by a vacuum process. For this reason, in the organic EL device 40, even if the film thickness of the first sealing layer 43 is thin and a defect occurs in the first sealing layer 43, it is doubled with the second sealing layer 46. It is described that by protecting, deterioration of the organic EL element 42 due to moisture can be suppressed.

JP 2009-259690 A JP2011-40347A

In the organic EL element 30 of Patent Document 1, the inorganic sealing layer 38 is organically filled with a liquid prepared by dissolving polysilazane in an arbitrary organic solvent (hereinafter referred to as polysilazane solution) with an arbitrary film forming apparatus such as a syringe. It is formed by applying the coating so as to be in contact with the side surface of the layer 36, the element substrate 31 and the sealing substrate 37, and then drying and curing. However, when the inorganic sealing layer 38 is formed by such a method, repelling occurs, pinholes are generated in the inorganic sealing layer 38, and moisture may enter from there to cause deterioration of the organic EL element. is there.
Further, after the unit before the formation of the inorganic sealing layer 38 is cut and before the polysilazane solution is applied to the side surface of the organic filling layer 36, moisture enters from the side surface of the organic filling layer 36, and the organic filling layer 36. There is a possibility that moisture taken into the inside may affect the reliability of the organic EL element 30.

Furthermore, in the organic EL device 40 of Patent Document 2, the first sealing layer 43 is formed by a vacuum process, which is not preferable in terms of productivity and cost. Further, when the organic filling layer 44 is cured, mechanical damage due to curing shrinkage is caused on the first sealing layer 40 and the cathode on the organic EL element 42, and moisture taken into the organic filling layer 44 is organic EL. The reliability of the device 40 may be affected.
The present invention has been made in view of the above problems, to suppress the infiltration of water into the interior, there is provided a method of manufacturing an organic electroluminescence panel for display performance and decrease in reliability is suppressed .

To the above problem, the invention according to claim 1 of the present invention, the surface of the insulating substrate, forming an organic electroluminescence device,
Applying or printing a hygroscopic adhesive material composed of a moisture absorbent and a resin material in a closed loop shape on the surface of the sealing substrate;
Applying or dropping an organic filler in a closed region surrounded by the moisture-absorbing adhesive material; and
The organic electroluminescence element forming surface of the insulating substrate and the organic filler adhering surface of the sealing substrate are opposed to each other so that the organic electroluminescence element is covered with the organic filler, and the element substrate and Bonding the sealing substrate; and
Curing the moisture-absorbing adhesive material to form a moisture-absorbing seal layer, and fixing the element substrate and the sealing substrate;
Applying a solution containing an inorganic material to a side surface of the cured moisture-absorbing adhesive material exposed from the insulating substrate and the sealing substrate, and curing the solution containing the inorganic material to form an inorganic sealing layer;
It is a manufacturing method of the organic electroluminescent panel characterized by including.
In the invention according to claim 2 of the present invention, the solution containing the inorganic material is a solution containing polysilazane, and the inorganic sealing layer is formed by drying the solution containing polysilazane. It is characterized by doing.

According to the method for producing an organic electroluminescence panel of the present invention, an organic electroluminescence panel having a high moisture infiltration suppressing effect can be produced without going through complicated steps such as forming a protective film under vacuum.

  ADVANTAGE OF THE INVENTION According to this invention, deterioration of an organic electroluminescent element can be prevented and the organic electroluminescent panel which has high display performance and high reliability can be obtained.

It is sectional drawing which shows one structural example of the organic electroluminescent panel of this invention. It is the top view and sectional drawing which show an example of the manufacturing process of the organic electroluminescent panel of this invention. It is the top view and sectional drawing which show an example of the manufacturing process of the organic electroluminescent panel of this invention. It is sectional drawing which shows the structure of the electroluminescent element described in patent document 1. FIG. It is sectional drawing which shows the structure of the organic electroluminescent apparatus described in patent document 2. FIG.

1. Configuration of Organic Electroluminescence Panel Hereinafter, the configuration of the organic electroluminescence panel according to the present invention (hereinafter appropriately referred to as an organic EL panel) will be described based on an embodiment using FIG. In the following embodiment, an organic EL panel 10 having a top emission structure shown in FIG. 1 will be described. However, the configuration of the organic EL panel according to the present invention is not limited to this. The organic EL panel according to the present invention may have a bottom emission structure or a double-sided light emitting structure.
FIG. 1 is a cross-sectional view showing an embodiment of an organic EL panel 10 according to an embodiment of the present invention. The organic EL panel 10 of the present invention includes an element substrate 11, a plurality of organic EL elements each including a first electrode layer 12, an organic light emitting medium layer 13, and a second electrode layer 14 provided on the element substrate 11, and an organic EL panel. A filling layer 16, a hygroscopic sealing layer 18, and an inorganic sealing layer 19 are provided.

  The second electrode layer 14 is formed so as to cover the plurality of first electrode layers 12 patterned on the element substrate 11 and the plurality of organic light emitting medium layers 13 formed on the first electrode layer 12. . Further, the first electrode layer 12 and the organic light emitting medium layer 13 are partitioned by the partition wall 15 and become pixel electrodes corresponding to the respective pixels. The organic filling layer 16 is a layer for blocking the organic EL element including the first electrode layer 12, the organic light emitting medium layer 13, and the second electrode layer 14 from the atmosphere. The moisture-absorbing seal layer 18 fixes the element substrate 11 and the sealing substrate 17, suppresses the penetration of moisture into the organic EL panel 10, and organically adheres to the element substrate 11 and the sealing substrate 17 during vacuum bonding. This is a layer that becomes the dam material of the filling layer 16. The inorganic sealing layer 19 is a protective layer for covering the side surface of the moisture-absorbing seal layer 18 and blocking the organic EL element from the outside air.

  The element substrate 11 is made of an insulating substrate such as glass or plastic film. In FIG. 1, the top emission type organic EL panel 10 is described. However, in the case of the bottom emission type in which the organic EL panel 10 extracts light emission from the substrate side, a light-transmitting material is used as the material of the element substrate 11. Used. As a material of the light-transmitting element substrate 11, glass, quartz, or a plastic film such as polyethersulfone or polycarbonate is used.

When the active matrix organic EL panel 10 is formed, a drive substrate on which a thin film transistor (TFT) is formed is used as the element substrate 11. A known thin film transistor is used as the thin film transistor. Specific examples of the thin film transistor include a thin film transistor mainly including an active layer in which a source / drain region and a channel region are formed, a semiconductor layer, a gate insulating film, and a gate electrode. The semiconductor layer of the thin film transistor is made of, for example, polythiophene, polyaniline, copper phthalocyanine, perylene derivative, amorphous silicon, polysilicon, or metal oxide.
The structure of the thin film transistor is not particularly limited, and examples thereof include a staggered type, an inverted staggered type, a bottom gate type, a top gate type, and a coplanar type. In addition, a color filter layer, a light scattering layer, a light polarizing layer, or the like may be provided on either surface of the element substrate 11.

The first electrode layer 12 is preferably formed of a material having a high work function, and is a metal composite oxide such as ITO (indium tin composite oxide) or indium zinc composite oxide, or zinc aluminum composite oxide, gold or It consists of a metal material such as platinum, a resin material in which fine particles of these metal oxides or metal materials are dispersed in an epoxy resin, an acrylic resin, or the like. The first electrode layer 12 may have a single layer structure made of any one of the above materials, or may have a laminated structure in which a plurality of layers made of any one of the above materials are stacked. Since the organic EL panel 10 is a top emission type, the first electrode layer 12 is made of a metal material having a high reflectance such as silver (Ag) in order to have the hole injection property and the reflection property as the first electrode layer 12. It is preferable that an ITO film is laminated thereon.
The optimum value of the film thickness of the first electrode layer 12 varies depending on the element configuration of the organic EL panel 10, but it is preferably 10 nm or more and 1000 nm or less, more preferably 10 nm or more and 300 nm or less, regardless of single layer or stacked layers. is there.

  The partition wall 15 is made of an insulating photosensitive material. The photosensitive material may be either a positive resist or a negative resist. The partition 15 is made of, for example, a polyimide material, an acrylic resin material, a novolac resin material, a fluorene material, or the like. Further, the partition wall 15 may be formed of a material obtained by adding a light shielding material or a water repellent to the above-described photosensitive material for the purpose of improving the display quality of the organic EL panel 10. Further, after the partition wall 15 is formed, plasma or ultraviolet light may be irradiated to impart liquid repellency to the ink to the partition wall 15. If the partition wall 15 does not have sufficient insulation, a current flows through the pixel electrode including the first electrode layer 12 and the organic light emitting medium layer 13 that are adjacent to each other through the partition wall 15, and the display is performed on the organic EL panel 10. Defects may occur or proper display may not be possible due to TFT malfunction.

The thickness of the partition wall 15 is preferably 0.5 μm or more and 5.0 μm or less. If the partition wall 15 is too thin, a leak current or a short circuit is likely to occur between adjacent pixels. In addition, when an organic light emitting ink having different light emission colors dissolved or dispersed in a solvent is used for each pixel, it is difficult to obtain an effect of preventing color mixing of the organic light emitting ink. If the partition wall 15 is too thick, the thickness of the organic EL panel 10 becomes larger than necessary.
The organic light emitting medium layer 13 includes an organic light emitting layer that emits light upon application of a voltage. The organic light emitting medium layer 13 may have a single layer structure composed of an organic light emitting layer, or may have a laminated structure in which a light emission auxiliary layer for improving light emission efficiency is laminated on the surface of the organic light emitting layer. The light emission auxiliary layer is, for example, a hole transport layer, a hole injection layer, an electron transport layer, or an electron injection layer.

  The organic light emitting layer may be an existing fluorescent light emitting material or phosphorescent light emitting material, such as 9,10-diarylanthracene derivative, pyrene, coronene, perylene, rubrene, 1,1,4,4-tetraphenylbutadiene, tris (8-quinolinolate). ) Aluminum complex, tris (4-methyl-8-quinolinolato) aluminum complex, bis (8-quinolinolato) zinc complex, tris (4-methyl-5-trifluoromethyl-8-quinolinolato) aluminum complex, tris (4-methyl) -5-cyano-8-quinolinolato) aluminum complex, bis (2-methyl-5-trifluoromethyl-8-quinolinolato) [4- (4-cyanophenyl) phenolate] aluminum complex, bis (2-methyl-5- Cyano-8-quinolinolato) [4- (4-cyanophenyl) Phenolate] aluminum complex, tris (8-quinolinolato) scandium complex, bis [8- (para-tosyl) aminoquinoline] zinc complex and cadmium complex, 1,2,3,4-tetraphenylcyclopentadiene, pentaphenylcyclopentadiene, Poly-2,5-diheptyloxy-para-phenylene vinylene, coumarin phosphor, perylene phosphor, pyran phosphor, anthrone phosphor, porphyrin phosphor, quinacridone phosphor, N, N'- Low molecular light emitting materials such as dialkyl-substituted quinacridone phosphors, naphthalimide phosphors, N, N′-diaryl-substituted pyrrolopyrrole phosphors, phosphorescent phosphors such as Ir complexes, polyfluorenes, polyparaphenylene vinylenes , Polymer materials such as polythiophene and polyspiro, Wherein these polymeric materials consisting of dispersed or copolymerized materials of low molecular weight material.

The hole transport layer is composed of metal phthalocyanines and metal-free phthalocyanines such as copper phthalocyanine and tetra-tert-butyl phthalocyanine copper, quinacridone compounds, 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane, N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-biphenyl-4,4′-diamine, N, N′-di (1-naphthyl) -N, N′-diphenyl −1,1′-biphenyl-4,4′-diamine and other aromatic amine-based low-molecular hole injection / transport materials, polyaniline, polythiophene, polyvinylcarbazole, poly (3,4-ethylenedioxythiophene) and polystyrenesulfonic acid Hole transport material such as a mixture thereof, polythiophene oligomer material, Cu ₂ O, Cr ₂ O ₃ , Mn ₂ O ₃ , FeO _x (x˜0.1), NiO, CoO, Pr ₂ O ₃ , Ag ₂ O, MoO ₂ , Bi ₂ O ₃ , ZnO, TiO ₂ , SnO ₂ , ThO ₂ , V ₂ O ₅ , Nb ₂ O ₅ , Ta ₂ O ₅ , MoO ₃ , WO ₃ , MnO ₂ and other inorganic materials, and other existing hole transport materials.

The organic light emitting medium layer 13 may be one in which an interlayer layer is formed between the organic light emitting layer and the hole transport layer. The interlayer layer is a layer that functions as an electronic block layer. By forming the interlayer layer between the organic light emitting layer and the hole transport layer, the light emission lifetime of the organic EL element is improved. In the top emission type organic EL panel 10, a hole transport layer, an interlayer layer, and an organic light emitting layer are sequentially laminated on the first electrode layer 12 to form an organic light emitting medium layer 13.
The interlayer layer is made of a polymer containing an aromatic amine such as polyvinyl carbazole or a derivative thereof, a polyarylene derivative having an aromatic amine in the side chain or main chain, an arylamine derivative, or a triphenyldiamine derivative.

The electron transport layer comprises 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (1-naphthyl) -1,3, It consists of electron transport materials such as 4-oxadiazole, oxadiazole derivatives, bis (10-hydroxybenzo [h] quinolinolato) beryllium complexes, and triazole compounds.
The electron injection layer is made of a material obtained by doping the above-described electron transport material with a small amount of alkali metal or alkaline earth metal having a low work function such as sodium, barium, or lithium.
The film thickness of the organic light-emitting medium layer 13 is 1000 nm or less, preferably about 50 to 200 nm, even when formed by a single layer or a stacked layer.

  The second electrode layer 14 is made of a material having a high electron injection efficiency into the organic light emitting medium layer 13 and a low work function. Specifically, the second electrode layer 14 is made of a single metal such as Mg, Al, Yb, Ba, Ca, Li or an oxide thereof on the side of the organic light emitting medium layer 13 of Al or Cu having high stability and conductivity. It is formed of a metal laminate in which a layer made of a compound such as fluoride and having a thickness of about 1 nm is formed. Further, in order to achieve both the efficiency of electron injection into the organic light emitting medium layer 13 and the stability of the second electrode layer 14, the second electrode layer 14 is made of Li, Mg, Ca, Sr, La, Ce having a low work function. , Er, Eu, Sc, Y, Yb and the like, and may be formed of an alloy made of a stable metal element such as Ag, Al, or Cu. Specifically, MgAg, AlLi, CuLi, etc. can be used as such an alloy.

In the so-called top emission type organic EL panel 10 in which light is extracted from the second electrode layer 14 side, the second electrode layer 14 is preferably formed of a light-transmitting material. In this case, the second electrode layer 14 has a metal composite oxide such as ITO (indium tin composite oxide), indium zinc composite oxide, or zinc aluminum composite oxide on the surface of a thin film layer made of Li and Ca having a low work function. The organic light emitting medium layer 13 may be doped with a small amount of a metal such as Li or Ca having a low work function, and a metal oxide such as ITO may be laminated.
The thickness of the second electrode layer 14 is not particularly limited, but is preferably about 10 nm to 1000 nm. In addition, when the second electrode layer 14 is used as a translucent electrode layer, the thickness of the second electrode layer 14 when using a metal material such as Ca or Li is about 0.1 nm to 10 nm. preferable.

The organic filling layer 16 is preferably made of liquid or grease-like silicon oil, fluorine oil, or the like.
The same material as that of the element substrate 11 can be used for the sealing substrate 17. The sealing substrate 17 used for the top emission type organic EL panel 10 is preferably made of a transparent material. Further, in the case of transmitting laser light for heating the frit glass, it is necessary to use a material that is transparent to the wavelength of the laser to be used.

  The moisture-absorbing seal layer 18 is made of a moisture-absorbing adhesive material in which a water absorbent is mixed with an acrylic resin combined with ultraviolet curing and heat curing. The moisture absorbent is preferably, for example, calcium oxide or barium oxide that chemically adsorbs moisture, or silica gel or zeolite that physically adsorbs moisture. These water absorbents can be used alone or in admixture of two or more. The particle diameter of the moisture absorbent is preferably about 1 μm or more and 5 μm or less.

  The inorganic sealing layer 19 is a protective layer for protecting the organic EL element from the outside air. The inorganic sealing layer 19 is made of an inorganic material, for example, a metal oxide such as silicon oxide or aluminum oxide, a metal fluoride such as aluminum fluoride or magnesium fluoride, or a metal nitride such as silicon nitride, aluminum nitride, or carbon nitride. Metal oxynitrides such as silicon oxynitride and metal carbides such as silicon carbide are used. In particular, it is preferable to use silicon nitride, silicon oxide, or silicon oxynitride having excellent moisture barrier properties as the inorganic sealing layer 19. In addition, as the inorganic sealing layer 19, a laminated film of a polymer resin film such as an acrylic resin, an epoxy resin, a silicon resin, or a polyester resin and an inorganic material film may be used. Furthermore, as the inorganic sealing layer 19, a laminated film in which a metal film such as aluminum, titanium, or gold is laminated together with a polymer resin film and an inorganic material film may be used.

2. Manufacturing method of organic electroluminescence panel The above-described manufacturing method of the organic EL panel 10 according to the present invention is implemented using FIGS. 2 (a) to 2 (f) and FIGS. 3 (a) to 3 (d). It demonstrates based on a form. 2A to 2F show an example of a manufacturing method in the case where four organic EL panels 10 are manufactured at the same time.

First, the element substrate 11 is prepared. At this time, it is preferable to reduce the moisture inside or on the surface of the element substrate 11 as much as possible by performing a heat treatment on the element substrate 11 in advance. Further, in order to improve the adhesion of the material laminated on the element substrate 11, the element substrate 11 is subjected to surface treatment such as ultrasonic cleaning treatment, corona discharge treatment, plasma treatment, ultraviolet ozone treatment according to the material. It is preferable to use after applying.
When the active matrix type organic EL panel 10 is formed, a driving substrate (not shown) in which a thin film transistor is formed on a substrate is used as the element substrate 11. In the case of forming a thin film transistor, a planarization layer is formed over the thin film transistor. The lower electrode (first electrode layer 12) of the organic EL element is formed on the planarization layer.

Subsequently, the first electrode layer 12 is formed on the element substrate 11. Depending on the material, the first electrode layer 12 may be a dry film forming method such as a resistance heating vapor deposition method, an electron beam vapor deposition method, a reactive vapor deposition method, an ion plating method, or a sputtering method, a gravure printing method, a screen printing method, or the like. It is formed by the wet film forming method.
When the thin film transistor is formed on the substrate, the drain electrode of the thin film transistor and the first electrode layer 12 of the organic EL element constituting each pixel of the organic EL panel so that the thin film transistor functions as a switching element of the organic EL panel 10. And electrically connect. The thin film transistor, the drain electrode, and the first electrode layer 12 of the organic EL panel are preferably connected through a connection wiring formed in the contact hole by forming a contact hole that penetrates the planarization layer.

After the first electrode layer 12 is formed, partition walls 15 are formed between adjacent anode patterns by photolithography. More specifically, the photosensitive resin composition is applied to a substrate, the photosensitive resin composition is pattern-exposed in a desired shape, the photosensitive resin composition is developed, and the remaining photosensitive resin composition is baked to form a partition wall. 15 is formed.
The photosensitive resin composition forming the partition 15 can be applied using a known coating method such as a spin coater, bar coater, roll coater, die coater, or gravure coater. Conventionally known exposure and development methods can be used for pattern exposure and development of the photosensitive resin composition. For firing the photosensitive resin composition formed in a desired pattern, a conventionally known firing method using an oven, a hot plate, or the like can be used.

The partition 15 is formed so as to partition the light emitting region corresponding to the pixel. In general, in an active matrix drive type display device, a first electrode layer 12 is formed for each pixel, and each pixel tries to occupy as wide an area as possible, so that the end of the first electrode layer 12 is covered. It is most preferable to form the partition walls 15 formed in a lattice shape.
Moreover, you may form the partition 15 in multistep shape. In that case, an insulating inorganic film made of SiO ₂ or SiN formed on the entire surface of the substrate is formed in a lattice shape for partitioning pixels by photolithography to form a first-stage partition wall 15. Then, a second-stage partition wall 15 made of a photosensitive resin composition is formed on the first-stage partition wall 15 by photolithography to form a second-stage partition wall 15.

Subsequently, the organic light emitting medium layer 13 is formed on the first electrode layer 12. Depending on the material, the organic light-emitting medium layer 13 is formed by a vacuum deposition method, a slit coating, a spin coating, a spray coating, a nozzle coating, a flexographic printing, a gravure printing, an intaglio offset printing, a relief printing, a coating method such as a relief printing, It can be formed by an inkjet method or the like.
Subsequently, the second electrode layer 14 is formed. The second electrode layer 14 can be formed using a resistance heating vapor deposition method, an electron beam vapor deposition method, a reactive vapor deposition method, an ion plating method, or a sputtering method depending on the material.

Next, using FIG. 2A to FIG. 2F and FIG. 3A to FIG. 3D, an organic material composed of the first electrode layer 12, the organic light emitting medium layer 13, and the second electrode layer 14 is used. A method for bonding the element substrate 11 provided with the EL element and the sealing substrate 17 will be described. In the following steps, the element substrate 11 and the sealing substrate 17 are bonded together via the organic filling layer 16 and the moisture absorption seal layer 18.
As shown in FIGS. 2 (a) and 2 (b), first, a hygroscopic adhesive material 18a made of an acrylic adhesive in which a moisture absorbent is mixed on the sealing substrate 17 is formed in a closed loop shape by dispenser or screen printing. Apply or print with. FIG. 2B is a cross-sectional view showing an AA ′ cross section of the sealing substrate 17 provided with the hygroscopic adhesive material 18a shown in FIG.

Next, as shown in FIG. 2C and FIG. 2D, an organic filler 16a such as fluorine oil is applied to the closed region surrounded by the hygroscopic adhesive material 18a applied or printed in a closed loop shape. Or dripping. FIG.2 (d) is sectional drawing which shows the BB 'cross section of the sealing substrate 17 after application | coating of the organic filler 16a shown in FIG.2 (c).
Subsequently, as shown in FIGS. 2E and 2F, the element substrate 11 on which the organic EL element is formed and the sealing substrate 17 are bonded together in a vacuum. At this time, the element substrate 11 and the sealing substrate 17 are bonded so that the organic EL element forming region of the element substrate 11 and the organic filler 16a application region of the sealing substrate 17 face each other. Thereafter, the unit in which the element substrate 11 and the sealing substrate 17 are bonded together is taken out into the atmosphere, and the hygroscopic adhesive material 18a is cured by heating and ultraviolet irradiation. Thereby, the hygroscopic seal layer 18 is formed.

The organic filler 16 a enclosed in the space sealed by the element substrate 11 on which the organic EL element is formed, the sealing substrate 17, and the hygroscopic seal layer 18 corresponds to the organic filler layer 16. Since the organic filler 16a is made of a liquid or grease-like material such as silicon oil or fluorine oil, the organic filler layer 16 is liquid or grease-like even after the hygroscopic seal layer 18 is formed. Thus, since the organic filling layer 16 is made of a material that does not harden, the adhesive strength of the moisture-absorbing seal layer 18 is important in order to ensure sufficient adhesion strength of the panel, but the epoxy adhesive material has low moisture permeability. Although excellent, the adhesive strength is inferior to acrylic adhesive materials. Therefore, as a material used for the moisture-absorbing seal layer 18, an acrylic ultraviolet-thermosetting adhesive that is an acrylic resin having excellent adhesive strength is used, and in order to achieve both adhesive strength and low moisture permeability, a moisture absorbent. Is used.
Subsequently, as shown in FIG. 3A, a unit obtained by curing the moisture-absorbing adhesive material 18a is divided to obtain a panel. The panel is obtained by cutting (scribing) and dividing (breaking) the units shown in FIGS. 2 (e) and 2 (f). FIG.3 (b) is sectional drawing which shows the DD 'cross section of the panel shown to Fig.3 (a).

  A polysilazane solution obtained by dissolving alkoxysilane and perhydropolysilazane in an inert organic solvent is applied to the side surface of the moisture-absorbing seal layer 18 formed on the panel of FIG. As the polysilazane solution, for example, OlamZ or OlamOZ manufactured by Art Breed Co., Ltd. is suitable. The polysilazane solution enters between the element substrate 11 and the sealing substrate 17 by capillary action. In this state, the inorganic sealing layer 19 shown in FIGS. 3C and 3D is formed by allowing the panel to stand at room temperature or heating in the atmosphere. The polysilazane solution is cured by hydrolysis due to absorption of moisture in the air, whereby a silica (SiOx) film that is the inorganic sealing layer 19 is formed. For this reason, you may make it promote volatilization of the solvent in a polysilazane solution by heating a panel. Here, FIG. 3D is a cross-sectional view showing an E-E ′ cross section of the panel shown in FIG.

In the organic EL panel 10 according to one embodiment of the present invention produced as described above, the side surface of the organic filling layer 16 sandwiched between the element substrate 11 and the sealing substrate 17 has a moisture absorption seal layer containing a moisture absorbent. 18. It is covered with an inorganic sealing layer 19 having an excellent moisture barrier property. For this reason, the inorganic sealing layer 19 prevents moisture from entering into the organic EL panel 10, and even if moisture enters from a small pinhole or crack generated in the inorganic sealing layer 19, the moisture absorption sealing layer The moisture absorbent in 18 adsorbs moisture chemically or physically. Therefore, in the organic EL panel 10 according to an embodiment of the present invention, deterioration of the organic EL element is prevented due to the influence of moisture.
In addition, in the organic EL panel 10 according to an embodiment of the present invention, a complicated vacuum process is performed in forming the inorganic sealing layer 19 having excellent moisture barrier properties and the moisture absorbing seal layer 18 having excellent moisture absorbing properties. High display performance and reliability can be obtained without any problems.

Hereinafter, the organic EL panel of the present invention will be further described with reference to examples and comparative examples, but the present invention is not limited to the following examples [Example 1].
A substrate on which a first electrode layer, an extraction electrode, an inorganic insulating layer made of a SiNx layer for protecting the TFT circuit, and a partition made of polyimide for partitioning pixels formed on the inorganic insulating layer are formed as an element substrate. Was used.

On the first electrode layer, a hole transport layer made of a mixture of poly (3,4-ethylenedioxythiophene) and polystyrenesulfonic acid was formed with a thickness of 20 nm by a spin coating method.
An organic light-emitting solution in which poly [2-methoxy-5- (2′-ethyl-hexyloxy) -1,4-phenyleneburene], which is an organic light-emitting material, is dissolved in toluene on a hole transport layer is spin-coated. Was applied. Subsequently, toluene was volatilized to form an organic light emitting layer with a thickness of 80 nm in combination with the hole transport layer to form an organic light emitting medium layer composed of the organic light emitting layer and the hole transport layer.

On the organic light emitting medium layer, a metal film made of Ba and Al was sequentially formed with a thickness of 5 nm and 100 nm by a resistance heating vapor deposition method to form a second electrode layer.
An acrylic UV-thermosetting combined adhesive mixed with calcium oxide, a moisture-absorbing adhesive material, is applied to the sealing substrate in a closed loop shape, and then a fluorine oil is applied in the UV-thermosetting combined adhesive applied in a closed loop shape. Was applied. The acrylic UV-thermosetting adhesive and fluorine oil were applied using a dispenser.

Using a vacuum bonding machine, the organic EL element forming surface of the element substrate and the fluorine oil application surface of the sealing substrate are opposed to each other so that the organic EL element is covered with fluorine oil, and then the element substrate and the sealing substrate are Bonding was performed at a chamber pressure of 30 Pa. Then, after irradiating ultraviolet rays with an ultraviolet ray dose of 3000 mJ / cm ² with an ultraviolet irradiation device, the acrylic ultraviolet / thermosetting adhesive is cured by heating at 120 ° C. for 1 hour in a clean oven, The sealing substrate was fixed.

The organic EL panel was cut out by scribing and breaking the vacuum bonding unit in which the acrylic ultraviolet-heat curing combined adhesive was cured. Subsequently, after applying the polysilazane solution to the outer peripheral portion of the sealing substrate with a dispenser, the polysilazane solution was naturally dried in the air.
When the thus obtained organic EL panel of Example 1 (number of pixels: 960 × 540) was stored in an environment at a temperature of 60 ° C. and a relative humidity of 90% for 1000 hours, generation of bubbles and pixel defects was observed. There wasn't.

[Comparative Example 1]
In the same manner as in Example 1, except that an acrylic UV-thermosetting adhesive without mixing calcium oxide was used instead of the calcium oxide-mixing acrylic UV-thermosetting adhesive that is a moisture-absorbing adhesive material. An EL panel was produced. When the organic EL panel of Comparative Example 1 was stored in an environment of a temperature of 60 ° C. and a relative humidity of 90% for 700 hours, dark spots were observed in pixels near the moisture-absorbing seal layer 18 where the moisture-absorbing adhesive material was cured. It was. In addition, after 1000 hours of storage time, the dark spot expanded to the adjacent pixels.

[Comparative Example 2]
An organic EL panel was produced in the same manner as in Example 1 except that the polysilazane solution was not applied. When the organic EL panel of Comparative Example 2 was stored in an environment of a temperature of 60 ° C. and a relative humidity of 90% for 500 hours, a defect (dark area) that appeared to be intrusion of water from the outside occurred from the corner of the light emitting display area. . Moreover, after 1000 hours of storage time, the dark area further expanded.

10. Organic EL element (present invention)
DESCRIPTION OF SYMBOLS 11 ... Element board | substrate 12 ... 1st electrode layer 13 ... Organic luminescent medium layer 14 ... 2nd electrode layer 15 ... Partition 16 ... Organic filler layer 16a ... Organic filler 17 ... Sealing substrate 18 ... Hygroscopic sealing layer 18a ... Hygroscopic adhesive material 19 ... inorganic sealing layer 20 ... dispenser 30 ... organic EL element (conventional example)
31 ... element substrate 32 ... first electrode layer 33 ... organic light emitting medium layer 34 ... second electrode layer 35 ... organic electroluminescent layer 36 ... organic filling layer 37 ... sealing substrate 38 ... inorganic sealing layer 40 ... organic EL device ( Conventional example)
41 ... element substrate 42 ... organic EL element 43 ... first sealing layer 44 ... organic filling layer 45 ... sealing substrate 46 ... second sealing layer

Claims (2)

Forming an organic electroluminescence element on the surface of the insulating substrate;
Applying or printing a hygroscopic adhesive material composed of a moisture absorbent and a resin material in a closed loop shape on the surface of the sealing substrate;
Applying or dropping an organic filler in a closed region surrounded by the moisture-absorbing adhesive material; and
The organic electroluminescence element forming surface of the insulating substrate and the organic filler adhering surface of the sealing substrate are opposed to each other so that the organic electroluminescence element is covered with the organic filler, and the element substrate and Bonding the sealing substrate; and
Curing the moisture-absorbing adhesive material to form a moisture-absorbing seal layer, and fixing the element substrate and the sealing substrate;
Applying a solution containing an inorganic material to a side surface of the cured moisture-absorbing adhesive material exposed from the insulating substrate and the sealing substrate, and curing the solution containing the inorganic material to form an inorganic sealing layer;
A method for producing an organic electroluminescence panel, comprising: The solution containing the inorganic material is a solution containing polysilazane, the organic electroluminescent panel according to claim 1, characterized by forming the inorganic sealing layer by drying the solution containing the polysilazane Production method.

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