JP6299075B2 - Organic EL device and manufacturing method thereof - Google Patents

Description

  The present invention relates to an organic EL (Electroluminescence) device and a method for manufacturing the same, and more specifically, an electronic device such as a flat panel display used for a portable terminal such as a television, a personal computer monitor, and a cellular phone. In addition to the above, the present invention relates to an organic EL device using an organic EL element that may be employed in a surface-emitting light source, illumination, a light-emitting advertising body, and the like, and a manufacturing method thereof.

An organic EL element is expected as a flat panel display (hereinafter collectively referred to as an organic EL device) 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.
FIG. 1 is a cross-sectional view showing a conventional organic EL device. As shown in FIG. 1, a conventional organic EL element includes a first electrode layer 12, an organic light emitting medium layer 13, and a second electrode layer 14 on an EL element substrate (hereinafter also simply referred to as a substrate) 11. The adhesive 15 layer, the desiccant 16, the sealing substrate 17, and the partition 18 are comprised. The main part of the organic EL element is at least one of two electrode layers having translucency (an anode layer and a cathode layer, also simply referred to as an electrode), that is, a first electrode layer 12 and a second electrode layer. The organic light emitting medium layer 13 is sandwiched between the electrode layer 14 and the electrode layer 14. The organic light emitting medium layer 13 emits light by applying a voltage between both the electrodes 12 and 14 and passing a current. That is, the organic EL element is a self-luminous display element.

However, this organic EL element has a problem that it deteriorates when affected by moisture and oxygen in the atmosphere. In view of this, an organic EL element is known in which a moisture absorption layer is included in the main part of the organic EL element to prevent deterioration due to the influence of moisture and oxygen in the atmosphere. More specifically, in this organic EL element, a space by a digging portion is provided at an appropriate position of a main portion made of metal or glass, and a moisture absorption layer is formed in the digging portion.
The following technique is disclosed regarding the moisture absorption layer provided so that it may be included in the principal part of an organic EL element as mentioned above.
For example, the thing of patent document 1 knead | mixes the particle | grains which have a moisture absorption function in binder resin, and the thing processed into the sheet form is affixed on the principal part of an organic EL element.

  For example, the thing of patent document 2 has arrange | positioned the moisture absorption member in the state which does not contact the laminated body on the opposing surface with the laminated body by a translucent electrode. The hygroscopic member is a viscous inert liquid or inert gel-like member containing an adsorbent. However, in any of the methods, in order to make the surface of the hygroscopic agent a hollow structure that does not contact the second electrode, it is necessary to form a digging portion so that the hygroscopic agent is accommodated therein. . As a result, the processing process and the cost of the dug portion are excessively generated, and there is a problem that the thermal conductivity is lowered due to the hollow structure. Furthermore, this decrease in thermal conductivity has a problem that it is difficult to increase the size of the organic EL element.

  In addition, for example, the one described in Patent Document 3 is provided on a flat plate in order to solve the problem caused by the dug portion in which the hygroscopic agent disclosed in Patent Documents 1 and 2 described above has a hollow structure. An organic filling layer is provided, a hygroscopic layer is formed by dispersing and blending particles having a hygroscopic function therein, and bonded to the EL element substrate on which the second cathode is formed to form a solid sealing structure. is there.

JP 2002-280166 A JP 2003-163076 A JP 2009-037808 A

  However, as shown in the organic EL device and the manufacturing method of Patent Document 3 described above, when the sealing structure is formed by bonding the substrate formed with the hygroscopic agent and the EL element substrate formed up to the second electrode, the moisture absorbing function is achieved. The second electrode receives a local stress due to the pressure of the upper and lower substrates when the held particles absorb moisture and deform or are bonded together in a reduced pressure atmosphere, causing a problem. The problem is that the organic EL (display) device causes a display defect due to a dielectric breakdown (short) caused by local stress between the first electrode and the second electrode.

  The present invention has been made in view of such problems. The object of the present invention is to absorb moisture from a hygroscopic substance disposed in an organic filling layer in a solid sealing structure of an organic EL element. An organic EL device in which dielectric breakdown does not occur between the first electrode and the second electrode even when the second electrode is subjected to local stress due to deformation or pressure of the upper and lower substrates when bonded in a reduced pressure atmosphere And a manufacturing method thereof.

The present invention has been made to achieve such an object. The invention according to claim 1 includes at least a first electrode layer (22) and an organic light emitting layer on a flat substrate (21). An organic light emitting medium layer (23), a second electrode layer (24), an organic filling layer (27) containing a hygroscopic substance (29) having hygroscopic performance, an adhesive layer (28), a sealing substrate ( 32) and a cushion layer (26) for relieving local stress of the hygroscopic substance (29), the second electrode layer (24) and the organic EL device Provided between the organic filling layer (27), the organic filling layer (27) further contains a photo-curable material, and the cushion layer (26) has a mesh structure. This is an organic EL device.

The invention according to claim 2 of the present invention is the organic EL device according to claim 1, wherein the cushion layer (26) contains at least a photocurable material.
In the invention according to claim 3 of the present invention, the second electrode layer (24) is covered with the cushion layer (26), and the cushion layer (26) and the organic filling layer (27) The organic EL device according to claim 1 or 2 , wherein the periphery is surrounded by an adhesive layer (28) .

Further, in the invention according to claim 4 of the present invention, the hardness of the cushion layer (26) is Shore E90 or less including softness below a measurement limit. The organic EL device described in 1.
The invention according to claim 5 of the present invention is characterized in that the moisture vapor transmission rate of the cushion layer (26) is 50 g / m ² · day or more. The organic EL device according to any one of the above.

In the invention according to claim 6 of the present invention, the cushion layer (26) is made of a water-repellent or hydrophobic material, according to any one of claims 1 to 5. This is an organic EL device.
The invention according to claim 7 of the present invention is characterized in that the cushion layer (26) is made of a gel-like or rubber-like material. This is an organic EL device.

The invention according to claim 8 of the present invention is a method of manufacturing an organic EL device having a step of sequentially laminating functional layers on a flat substrate, and at least the first electrode layer (22) is formed. A step (S10), a step (S20) of forming an organic light emitting medium layer (27) including an organic light emitting layer, a step (S30) of forming a second electrode layer (24), a photocurable material, Between the step (S40) of forming an organic filling layer (27) containing a hygroscopic substance (29) having hygroscopic performance, and between the second electrode layer (24) and the organic filling layer (27). A step (S50) of forming a cushion layer (26) having a mesh structure and covering the second electrode layer (24), and surrounding the organic filling layer (27) and the cushion layer (26) By forming the adhesive layer (28), the hygroscopic substance ( A step (S60) that enables mitigating local stress of 9), a method of manufacturing an organic EL device characterized by having a step (S70) of forming a sealing substrate (32).

  According to the present invention, in the solid sealing structure of the organic EL element, the hygroscopic substance disposed in the organic filling layer absorbs moisture and deforms, or the pressure of the upper and lower substrates when bonded in a reduced pressure atmosphere, It is possible to provide an organic EL device that does not cause dielectric breakdown between the first electrode and the second electrode even when the second electrode receives local stress, and a method for manufacturing the same.

It is sectional drawing which shows the conventional organic EL apparatus. It is sectional drawing which shows the organic EL apparatus which concerns on Examples 1-5 of this invention. It is a top view which shows the mother substrate by which multiple organic EL devices of this invention were laid out. It is a flowchart for demonstrating the manufacturing method of the organic electroluminescent apparatus concerning this embodiment. It is sectional drawing which shows the comparative example of an organic electroluminescent apparatus.

Embodiments of the present invention will be described below with reference to the drawings. In the first embodiment, a top emission type organic EL display is described as an example. However, the present invention is not limited to this. That is, the top emission structure is exemplified as the organic EL device, but the organic EL device can also be applied to an organic EL device having a double emission structure or a bottom emission structure.
FIG. 2 is a cross-sectional view showing the organic EL devices according to the first to fifth embodiments of the present invention. The organic EL device of this embodiment includes at least a first electrode layer (hereinafter also simply referred to as a first electrode) 22, an organic light emitting medium layer 23, and a second electrode on an EL element substrate (hereinafter also simply referred to as a substrate) 21. A plurality of organic EL elements each including a layer (hereinafter also simply referred to as a second electrode) 24 are provided.

  More specifically, a plurality of first electrode layers 22 patterned on the substrate 21, a plurality of organic light emitting medium layers 23 formed on the plurality of first electrode layers 22, and a plurality of organic light emitting medium layers 23. Organic filling containing a second electrode layer 24 formed so as to cover the surface, a cushion layer 26 formed so as to cover the second electrode layer 24, and a hygroscopic material 29 disposed so as to contact the cushion layer 26 The layer 27, the adhesive layer 28 formed for bonding the substrate 21 and the sealing substrate 32 together, and the sealing substrate 32 are configured. Further, the organic filling layer 27 exhibits a function of absorbing the organic light emitting medium layer 23 with water vapor and other gases. The hygroscopic substance 29 has a hygroscopic property.

  As described above, the organic EL device according to the embodiment of the present invention includes at least the first electrode layer 22, the organic light emitting medium layer 23 including the organic light emitting layer, and the second electrode layer 24 on the flat substrate 21. The organic EL device is formed by laminating an organic filling layer 27 containing a hygroscopic substance 29 having hygroscopic performance, an adhesive layer 28, and a sealing substrate 32, and is a local stress of the hygroscopic substance 29. A cushion layer 26 for relaxing the above is provided between the second electrode layer 24 and the organic filling layer 27. The second electrode layer 24 was covered with a cushion layer and provided with an adhesive layer 28 surrounding the organic filling layer 27 and the cushion layer 26. The material of the organic filling layer 27 contains at least a thermosetting material or a photocurable material, and contains a hygroscopic substance 29 having hygroscopicity.

  As the board | substrate 21 which concerns on this invention, the board | substrate which has insulation, such as glass and a plastic film, can be used, for example. In particular, in the case of a bottom emission type in which light emission is extracted from the substrate side, a light-transmitting material is used as the material of the substrate. As a material for the translucent base material, it is only necessary that at least a first electrode layer 22 described later is formed on a plastic film such as glass, quartz, polyethersulfone, or polycarbonate.

In the case of forming an active matrix organic EL element, a driving substrate on which a thin film transistor (TFT) is formed is used as a substrate, and a known thin film transistor can be used as a thin film transistor to be used.
Specifically, a thin film transistor mainly including an active layer in which a source / drain region and a channel region are formed, a gate insulating film, and a gate electrode can be given. 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.

As a material for the semiconductor layer of the thin film transistor, a material such as polythiophene, polyaniline, copper phthalocyanine, or perylene derivative may be used. Alternatively, amorphous silicon, polysilicon, or metal oxide may be used as the material of the semiconductor layer. Further, a color filter layer, a light scattering layer, a light polarizing layer, or the like may be provided on either surface of the driving substrate on which the above-described thin film transistor (TFT) is formed.
These substrates 21 are preferably used after heat treatment is performed in advance to reduce moisture inside or on the surface of the substrate 21 as much as possible. Further, in order to improve the adhesion depending on the material laminated on the substrate 21, it is preferable to use after performing surface treatment such as ultrasonic cleaning treatment, corona discharge treatment, plasma treatment, or UV ozone treatment. .

Next, the first electrode layer 22 is formed on the substrate.
The thin film transistor is connected so as to function as a switching element of the organic EL display. For this purpose, the drain electrode of the thin film transistor and the first electrode layer 22 of the organic EL element constituting each pixel of the organic EL display are electrically connected. The thin film transistor, the drain electrode, and the first electrode layer 22 of the organic EL display are connected through a connection wiring formed in the contact hole through the planarization film (not shown).

  The first electrode layer 22 is partitioned by the partition walls 25 and serves as a pixel electrode corresponding to each pixel. As a material of the first electrode layer 22, it is preferable to select a material having a high work function such as ITO. As the material of the first electrode layer 12, a metal composite oxide such as ITO (indium tin composite oxide), indium zinc composite oxide, zinc aluminum composite oxide, or a metal material such as gold or platinum is used as it is. Can do. Alternatively, a material in which a fine particle dispersion film in which fine particles of these metal oxides or metal materials are dispersed in an epoxy resin, an acrylic resin, or the like can be used as a material for the first electrode layer 22.

  As described above, the organic EL device according to this embodiment is a top emission type organic EL display. Therefore, the first electrode layer 22 is formed by laminating an ITO film on a metal material such as Ag or Al that requires hole injection and reflectivity. The film thickness of the first electrode layer 22 varies depending on the element configuration of the organic EL display. The film thickness of the first electrode layer 22 is 10 nm or more and 1000 nm or less, more preferably 300 nm or less, regardless of whether it is a single layer or a stacked layer.

As a method for forming the first electrode layer 22, depending on the material, 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, a sputtering method, a gravure printing method, A wet film forming method such as a screen printing method can be used.
After the first electrode layer 22 is formed, partition walls 28 are formed between adjacent anode patterns by photolithography. More specifically, it includes at least a step of applying the photosensitive resin composition to the substrate 21 and a step of forming a partition pattern by pattern exposure, development, and baking.

  The partition wall 25 is formed so as to partition the light emitting region corresponding to the pixel. In general, in an active matrix drive display device, a first electrode layer 22 is formed for each pixel. A partition wall 25 is formed so as to cover an end of the first electrode layer 22 so that each pixel of the first electrode layer 22 can secure as large an area as possible. It is the most basic and preferable shape that the partition wall 25 has a lattice shape.

Moreover, the partition 25 can also be comprised in multistage shape. In that case, an insulating inorganic film formed of SiO ₂ or SiN on the entire surface of the substrate 21 is formed in a lattice shape separating pixels by a photolithography process, and becomes a first-stage partition wall. A second-stage partition made of a photosensitive resin is formed on the first-stage partition by photolithography.
The photosensitive material for forming the partition wall 25 may be either a positive type resist or a negative type resist, and may be a commercially available one, but it needs to have insulating properties. When the partition wall 25 does not have sufficient insulation, a current flows to the adjacent pixel electrode through the partition wall 25 (leakage current), and a display defect occurs. Also, proper display may not be possible due to TFT malfunction.

Specific examples of the photosensitive material for forming the partition wall 25 include polyimide, acrylic resin, novolac resin, and fluorene materials. However, the present invention is not limited to this.
Further, for the purpose of improving the display quality of the organic EL display, a light shielding material may be included in the photosensitive material. Furthermore, you may add a water repellent to the light-shielding material as needed. In addition, the light-shielding material may be formed by irradiating with plasma or UV (ultraviolet) and then imparting liquid repellency to the ink.

  In the step of forming the partition walls 25, the photosensitive resin is applied by a known application method such as a spin coater, a bar coater, a roll coater, a die coater, or a gravure coater. Next, in a step of forming a partition wall pattern by pattern exposure and development, a partition wall pattern is formed by a conventionally known exposure and development method. Regarding firing, firing can be performed by a conventionally known method using an oven, a hot plate or the like.

The thickness of the partition wall 25 is preferably in the range of 0.5 μm to 5.0 μm. By doing so, even when organic light-emitting materials having different emission colors are separately applied to each pixel using an organic light-emitting ink dissolved or dispersed in a solvent, color mixing with adjacent pixels is prevented. It becomes possible. On the other hand, if the partition wall 25 is too low, there is a high risk that problems such as dielectric breakdown, leakage current, and color mixing of the organic light-emitting ink will occur between adjacent pixels.
Subsequently, the organic light emitting medium layer 23 includes an organic light emitting layer that emits light upon application of a voltage. Although it may be constituted by a single layer composed of the organic light emitting layer, it may be constituted by a laminated structure in which a light emitting auxiliary layer for improving luminous efficiency is laminated in addition to the light emitting layer. Examples of the light emission auxiliary layer include a hole transport layer, a hole injection layer, an electron transport layer, and an electron injection layer.

Examples of hole transport materials include metal phthalocyanines such as copper phthalocyanine and tetra (t-butyl) copper phthalocyanine and metal-free phthalocyanines, 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, Aromatic amine low molecular hole injection and transport materials such as N′-diphenyl-1,1′-biphenyl-4,4′-diamine, polyaniline, polythiophene, polyvinylcarbazole, poly (3,4-ethylenedioxythiophene) ) and polymer hole transport materials such as a mixture of polystyrene sulfonic acid, polythiophene oligomer _{materials, Cu 2 O, Cr 2 O} 3, Mn 2 O 3 _{FeOx (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.

  In the case of a polymer EL display, an interlayer layer is preferably formed on the hole transport material. Examples of the material used for the interlayer layer include polymers containing aromatic amines such as polyvinyl carbazole or derivatives thereof, polyarylene derivatives having an aromatic amine in the side chain or main chain, arylamine derivatives, and triphenyldiamine derivatives. These materials can be dissolved or dispersed in a solvent and formed using various coating methods such as spin coating or letterpress printing.

  As the light-emitting material, 9,10-diarylanthracene derivatives, pyrene, coronene, perylene, rubrene, 1,1,4,4-tetraphenylbutadiene, tris (8-quinolinolato) 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, tri (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'-dialkyl-substituted quinacridone phosphor , Naphthalimide-based phosphors, N, N′-diaryl-substituted pyrrolopyrrole-based phosphors, phosphorescent phosphors such as Ir complexes, and other low-molecular light-emitting materials, polyfluorene, polyparaphenylene vinylene, polythiophene, polyspiro, etc. High molecular weight materials, and dispersion or low molecular weight materials in these high molecular weight materials. Copolymerized materials and can be used other conventional fluorescent light emitting material or phosphorescent material.

  Examples of electron transport materials include 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (1-naphthyl) -1 , 3,4-oxadiazole, oxadiazole derivatives, bis (10-hydroxybenzo [h] quinolinolato) beryllium complexes, triazole compounds, and the like can be used. Alternatively, an electron injection layer may be formed by doping a small amount of an alkali metal or alkaline earth metal having a low work function such as sodium, barium, or lithium into these electron transport materials. The organic light emitting medium layer 23 may be laminated with a metal oxide such as ITO by doping a small amount of a metal such as Li or Ca having a low work function.

  The film thickness of the organic light emitting medium layer 23 is 1000 nm or less, preferably about 50 to 200 nm, even when formed by a single layer or a stacked layer. As a method for forming the organic light emitting medium layer 23, depending on the material, a vacuum deposition method, a coating method such as slit coating, spin coating, spray coating, nozzle coating, flexographic printing, gravure printing, intaglio offset printing, letterpress offset printing, etc. Or a printing method, an inkjet method, or the like can be used.

  Subsequently, the second electrode layer 24 is formed. As the material for the second electrode layer 24, a substance having a high electron injection efficiency into the organic light emitting medium layer 23 and a low work function is used. Specifically, a single metal such as Mg, Al, Yb can be used. Further, as the material of the second electrode layer 24, about 1 nm of compounds such as Ba, Ca, Li, oxides thereof, and fluorides are sandwiched at the interface in contact with the light emitting medium, thereby improving the stability and conductivity. Al and Cu can be laminated and used. Alternatively, when the second electrode layer 24 is formed, Li, Mg, Ca, Sr, La, Ce, Er, Eu, Sc, Y, Yb having a low work function are used in order to achieve both electron injection efficiency and stability. An alloy system of one or more metals such as Ag and a stable metal element such as Ag, Al, or Cu may be used. More specifically, alloys such as MgAg, AlLi, and CuLi can be used.

  In the case of a so-called top emission structure in which light is extracted from the second electrode side, it is necessary to select a material having translucency. In this case, after thinly providing Li and Ca having a low work function, a metal composite oxide such as ITO (indium tin composite oxide), indium zinc composite oxide, or zinc aluminum composite oxide may be laminated.

  As described above, the organic light emitting medium layer 23 may be laminated with a metal oxide such as ITO by doping a small amount of a metal such as Li or Ca having a low work function. As a method for forming the second electrode 24, 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 can be used depending on the material. Although there is no restriction | limiting in particular in the thickness of the 2nd electrode 24, About 10 nm-1000 nm are preferable. Moreover, when using the 2nd electrode 24 as a translucent electrode layer, when using metal materials, such as Ca and Li, about 0.1-10 nm is preferable.

  Subsequently, the entire surface of the second electrode 24 is covered with the cushion layer 26. The cushion layer 26 protects the second electrode 24 from local stress due to the hygroscopic material 29. Further, the cushion layer 26 is pasted on the entire surface of the second electrode 24 in the form of a sheet. Alternatively, the liquid cushion layer 26 may be applied by a dispenser application method, a screen printing method, or the like. The liquid material is preferably in the form of a gel or rubber, and the hardness of the cured product coated with a sheet or liquid is preferably soft in order to protect the second electrode 24 from the hygroscopic material 29, It is preferable that it is less than Shore E90 of Association Standard (SRIS). In addition, about the hardness below Shore E90, even the softness below a measurement limit shall be included. That is, it is preferable that the hardness of the cushion layer 26 is not more than Shore E90 including softness below the measurement limit.

When the cushion layer 26 is cured, a thermosetting material can be used, but a photocurable material can also be used.
Further, the cushion layer 26 preferably has a high water vapor transmission rate so that water vapor can quickly reach the organic filling layer 27 containing the hygroscopic material 29 having hygroscopicity thereon. It is preferable that the moisture vapor transmission rate of the cushion layer 26 is 50 g / m ² · day or more.

In addition, a material having water repellency or hydrophobicity is used for the cushion layer 26 so that the cushion layer 26 itself does not retain water. Therefore, as a material of the cushion layer 26, for example, a silicone resin or a fluorine resin is preferable. Further, the thickness of the cushion layer 26 is preferably about twice as large as the particle diameter of the hygroscopic substance 29 in order to ensure cushioning properties. However, the thickness is not limited.
As described above, the material of the cushion layer 26 is preferably a water repellent or hydrophobic material. The cushion layer 26 is preferably in the form of a gel or rubber.

Subsequently, an organic filling layer 27 containing a hygroscopic material 29 having a hygroscopic property is formed on the cushion 26 in order to protect the organic EL element from air and moisture. The hygroscopic substance 29 contained in the organic filling layer 27 includes a chemical hygroscopic substance or a physical hygroscopic substance. Examples of the chemical hygroscopic substance include diphosphorus pentoxide (P ₂ O ₅ ) and calcium oxide (CaO). Examples of the physical hygroscopic substance include aluminum oxide (Al ₂ O ₃ ) and zeolite (alumina silicate). Moreover, as a particle size, it is 0.01-1000um, Preferably, it is 0.1-100um. The content of the hygroscopic substance 29 in the organic filling layer 27 is 1% to 90% by weight, preferably 15% to 65% by weight. One or several types of chemical hygroscopic substances may be used, and the same applies to physical hygroscopic substances.

  The organic filler is preferably chemically and thermally stable and preferably has water repellency or hydrophobicity, and examples thereof include silicone resins. The organic filling layer 27 containing the hygroscopic substance 29 having hygroscopicity is preferably formed so as to cover the entire surface of the panel, and examples of the forming method include a dispenser coating method and a screen printing method. The formed can be used in liquid form, but it is preferably cured. Therefore, the organic filler forming the organic filler layer 27 is preferably a thermosetting type or a photocurable type.

Subsequently, an adhesive layer 28 is formed so as to surround the cushion layer 26 and the organic filling layer 27 containing the hygroscopic substance 29, and a sealing substrate 32 is laminated thereon and sealed. A thermosetting material can be used as the material of the adhesive layer 28. However, considering the influence of heat on the organic EL device, the adhesive layer 28 is preferably formed of a photo-curing material. As the adhesive layer 28 formed of a photocurable material, for example, radical systems using various acrylates such as ester acrylate, urethane acrylate, epoxy acrylate, melamine acrylate, acrylic resin acrylate, and the like, and resins such as urethane polyester Examples thereof include an adhesive layer, a cationic adhesive layer using a resin such as epoxy and vinyl ether, and a thiol / ene-added resin adhesive layer. Among these, a cationic adhesive layer that is not inhibited by oxygen and that undergoes a polymerization reaction even after light irradiation is preferable. As the cationic curable type, an ultraviolet curable epoxy resin adhesive layer is preferable. More preferably, it is an ultraviolet curable adhesive layer that cures within 10 seconds to 90 seconds when irradiated with ultraviolet rays of 100 mW / cm ² or more. By curing within this time range, the ultraviolet curable adhesive layer can be sufficiently cured and provided with appropriate adhesive strength without causing adverse effects on other components due to ultraviolet irradiation. Also, from the viewpoint of the efficiency of the production process, it is preferable to cure the ultraviolet curable adhesive layer in the above-described time range within 10 seconds to 90 seconds. Regardless of the type of the adhesive layer 28, a material having low moisture permeability and high adhesion is preferable. As an example of a method for forming the adhesive layer 28 on the sealing substrate 32, a dispenser coating method, a screen printing method, and the like can be given.

  It is preferable to mix a spacer 30 for controlling the distance (also referred to as a gap) between the sealing substrate 32 and the EL element substrate 21 into the adhesive layer 28. By mixing the spacer 30 in the adhesive layer 28, the distance between the sealing substrate 32 and the EL element substrate 21 can be made uniform. In addition, by mixing the spacer 30 in the adhesive layer 28, it is possible to prevent the organic filling layer 27 and the cushion layer 26 from being pushed out of the scribe region by pressing when the substrates are bonded together. As the shape of the spacer 30, a spherical shape can be used. However, if the gap between the substrates can be controlled, the shape of the spacer 30 is not limited to a spherical shape. In addition, if it is the spherical spacer 30, a thing with a diameter of 1.0 micrometer or more and 100 micrometers or less can be used. However, the spherical spacer 30 preferably has a diameter equal to or less than the thickness of the cushion layer 26 and the organic filling layer 27 combined. When the thickness is larger than the total thickness of the cushion layer 26 and the organic filling layer 27, it is not preferable because a gap is hindered when the substrates are bonded to each other. As the material of the spacer 30, resin, glass, or the like can be used, but it is not particularly limited as long as the material can withstand pressing during bonding.

  As the sealing substrate 32, a plastic film such as glass, polyethylene terephthalate (PET), polyethersulfone (PES), polyethylene naphthalate (PEN) is used in the case of a top emission type organic EL element that requires transparency. Can be used. In the case of a bottom emission type organic EL element that does not particularly require transparency, a metal material such as stainless steel or aluminum, an opaque glass, or a plastic material may be used as the sealing substrate 32 in addition to the above materials. it can.

Next, an example of the application transfer process of the organic filling layer 26 containing the hygroscopic substance 29 having the hygroscopic property, the cushion layer 26 and the adhesive layer 28 formed so as to surround them will be described.
First, an organic filling layer 27 containing a hygroscopic substance 29 having a hygroscopic property is formed on the sealing substrate 32, and a cushion layer 26 is formed thereon so as to cover the organic filling layer 27. Thereafter, the adhesive layer 28 is formed so as to surround the one or more organic filling layers 27 and the cushion layer 26. Examples of the forming method include a dispenser coating method and a screen printing method. Further, the adhesive layer 28 may be formed on the EL element substrate side after the second electrode 24 is formed.

  You may form so that it may have a space between the laminated body of the cushion layer 26 and the organic filling layer 27, and the contact bonding layer 28. FIG. Since there is a space between the laminate of the adhesive layer 28, the cushion layer 26, and the organic filling layer 27, the cushion layer 26 or the organic filling layer 27 is heated by heating because it is pressed at atmospheric pressure after bonding. Can spread wet. On the other hand, the adhesive layer 28 may be formed so as to be in contact with the laminated body of the cushion layer 26 and the organic filling layer 27, and the laminated body of the adhesive layer 28, the cushion layer 26, and the organic filling layer 27 is in contact with the air. It is possible to eliminate the space to enter and improve the sealing performance.

FIG. 3 is a plan view showing a mother substrate on which a plurality of organic EL devices of the present invention are laid out.
After the sealing substrate 32 and the EL element substrate 21 are bonded together in a reduced pressure atmosphere, when the bonded substrate is taken out into the atmosphere, the laminate of the cushion layer 26 and the organic filling layer 27 and the adhesive layer 28 are 3, the sealing substrate 32 and the substrate 21 are bonded to each other with a uniform thickness by receiving a uniform pressure from the outside via the sealing substrate 32 and the EL element substrate 21. It becomes.

Next, a case where a plurality of EL element substrates 21 each serving as an organic EL device are formed on the mother substrate as shown in FIG. 3 will be described.
A closed loop outer peripheral seal 31 formed so as to surround each EL element substrate is preferably formed on the end portion of the mother substrate or a sealing substrate having a size corresponding to the end portion of the mother substrate. Since the sealing substrate 32 and the EL element substrate 21 are bonded to each other under a reduced pressure atmosphere, the outer peripheral seal 31 has a negative pressure by forming the outer peripheral seal 31. Then, since the adhesive layer 28 is not cured, it can be bonded with a uniform pressure at atmospheric pressure, and the gap of the adhesive layer 28 can be made uniform. Further, it is possible to prevent the sealing substrate 32 and the element substrate 21 from peeling off or air from entering the inside of the bonding unit from the outside.

As the outer peripheral sealant, the same material as that of the adhesive layer 28 can be used, and the spacer 30 is preferably mixed in the same manner as the adhesive layer 28. Further, the outer peripheral seal 31 may be formed by a dispenser coating method, a screen printing method, or the like, similar to the adhesive layer 28, and may be formed at the same time as the adhesive layer 28.
After the adhesive layer 27 and the outer peripheral seal 31 are formed, the unit bonded under reduced pressure is taken out into the atmosphere, irradiated with light, and the gap between the adhesive layer 28 and the outer peripheral seal 31 is formed and cured. The adhesive layer 28 and the outer peripheral seal 31 are formed so as to be in contact with both the sealing substrate 32 and the element substrate 21 by the pressure at the time of bonding, and the unit is completed.

Next, with reference to FIG. 4, the manufacturing method of the organic EL device according to this embodiment will be described.
FIG. 4 is a flowchart for explaining a method of manufacturing the organic EL device according to this embodiment. As shown in FIG. 4, the manufacturing method of the organic EL device according to this embodiment includes steps (S10) to (S70). That is, a step (S20) of forming an organic light emitting medium layer (13) including an organic light emitting layer, a step (S30) of forming a second electrode layer (24), and a hygroscopic substance (29) having hygroscopic performance. A step (S40) of forming an organic filling layer (27) containing, a step (S50) of forming a cushion layer (26) covering the second electrode (24), and a step of forming an adhesive layer (28) (S60). And a step (S70) of forming the sealing substrate (32).

  Then, in the step (S50) of forming the adhesive layer (28), the organic filler layer (27) and the cushion layer (26) are surrounded by the adhesive layer (28), so that the hygroscopic substance ( 29) It is characterized by relieving local stress.

  The second embodiment will also be described with reference to FIG. 2 used for the description of the first embodiment. In Example 1, it was explained that the cushion layer 26 should have high water vapor permeability and good hygroscopicity. The reason is that if the water vapor permeability of the cushion layer 26 is high, the water vapor that has entered from the outside quickly reaches the hygroscopic material 29 due to its good hygroscopicity, so that the organic EL device can be protected from the water vapor. Further, when the cushion layer 26 is formed in a sheet shape, a gel shape, or a cured product, the cushion layer 26 is porous and has cushioning properties. Because of the cushion layer 26, the organic EL device can easily avoid dielectric breakdown over and below the first electrode 22 even when subjected to local stress on the second electrode 24 by the hygroscopic substance 29 having hygroscopicity. Become.

  A third embodiment will also be described with reference to FIG. 2 used to describe the first embodiment. In Example 2, the cushion layer 26 itself was made of a porous material. In this regard, the third embodiment employs a manufacturing method in which fine hole processing is performed on the cushion layer 26. As a result, the organic EL device can cause water vapor entering from the outside to quickly reach the hygroscopic substance 29. That is, the getter effect is not reduced. In addition, since the cushion layer 26 itself has a cushioning property, it is easy to avoid dielectric breakdown over and below the first electrode 22 even when subjected to local stress on the second electrode 24 by the hygroscopic substance 29.

  Example 4 will also be described with reference to FIG. 2 used to explain Example 1. FIG. In Example 3, a fine hole was formed in the cushion layer. However, in Example 4, by using a mesh (mesh structure) for the cushion layer, moisture entering from the outside is quickly absorbed by moisture. The first electrode 22 against the local stress applied to the second electrode 24 by the hygroscopic substance 29 having hygroscopicity, because it can reach the active substance 29, has no cushioning effect, and has a cushioning property. It is possible to suppress dielectric breakdown across the top and bottom.

Example 5 will also be described with reference to FIG. 2 used to explain Example 1. FIG. Example 5 is another frame provided in order to explain each requirement in more detail in Example 1. In Example 5, the comparison result with the comparative example is also described. In addition, this invention is not limited to these Examples 1-5.
First, an organic EL device of Example 5 shown in FIG. 2 was produced. The substrate 21 already includes a first electrode layer 22, an extraction electrode, an inorganic insulating layer made of a SiNx layer for protecting the TFT circuit, and a resin insulating layer made of polyimide on the inorganic insulating layer, and the insulating layer is a partition wall for partitioning pixels. The TFT substrate 21 formed as 25 was used. In addition, since FIG. 2 is shared by Examples 1-5, the code | symbol 21 of FIG. 2 is called the TFT substrate 21 as it is.

Next, a hole transport layer made of a mixture of poly (3,4 ethylenedioxythiophene) and polystyrenesulfonic acid was formed on the first electrode layer 22 with a thickness of 20 nm by spin coating.
Next, poly [2-methoxy-5- (2′-ethyl-hexyloxy) -1,4-phenyleneburene], which is an organic light-emitting material, is dissolved in toluene on the hole transport layer, and organic by spin coating. A light emitting layer was formed, and an organic light emitting medium layer 23 having a thickness of 80 nm was formed together with the hole transport layer.

Next, the 2nd electrode layer 24 which consists of Ba and Al was formed with thickness of 5 nm and 2 nm by the resistance heating vapor deposition method by the vapor deposition method, respectively.
Subsequently, an organic filling layer containing zeolite was applied to a flat sealing substrate by a screen printing method, and annealed in an inert gas at 250 ° C. for 2 hours to form an organic filling layer 27.

Next, a cushion layer having a water vapor transmission rate of 50 g / m ² · day and a thickness of 100 μm is pasted on the organic filling layer 27, an adhesive layer 28 is applied around the cushion layer, and a TFT substrate formed to Ba and Al is pasted together. A sealed organic EL device was produced by irradiation with 5000 mJ of ultraviolet rays.
When the organic electroluminescence panel thus obtained was put into a 60 ° C. and 90% standing test, black spots, dark areas, and dark spots due to vertical dielectric breakdown were not seen even after 1000 hours.

(Comparative example)
FIG. 5 is a cross-sectional view showing a comparative example of an organic EL device. In addition, the same code | symbol is attached | subjected to the location of the same effect as each part shown in FIG. 2, and description is abbreviate | omitted.
An organic EL device excluding the cushion layer described in Example 5 was produced, and a 60 ° C. and 90% standing test was performed in the same manner. As a result, black spots caused by dielectric breakdown over 240 hours were observed. Dark areas and dark spots were not seen.
From the above results, it was confirmed that Example 5 was superior to Comparative Example 1 in that there was no defect due to dielectric breakdown over the top and bottom.

  As described above, according to the present invention, by providing a cushion layer between the second electrode and the organic filling tank containing the hygroscopic substance having hygroscopic performance, in the solid sealing structure of the organic EL element, As the hygroscopic substance disposed in the organic filling layer absorbs moisture and deforms, even if the second electrode receives local stress, dielectric breakdown does not occur between the first electrode and the second electrode. An organic EL device and a manufacturing method thereof can be provided.

11, 21 ... EL element substrate (flat substrate, TFT substrate)
DESCRIPTION OF SYMBOLS 12, 22 ... 1st electrode layer 13, 23 ... Organic luminescent medium layer 14, 24 ... 2nd electrode layer 15, 28 ... Adhesive layer 16 ... Desiccant 17, 32 ... Sealing board | substrates 18 and 25 ... Partition 26 ... Cushion layer 27 ... Organic filling layer 29 ... Hygroscopic material 30 ... Spacer 31 ... Outer seal

Claims (8)

On a flat substrate, at least a first electrode layer, an organic light emitting medium layer including an organic light emitting layer, a second electrode layer, an organic filling layer containing a hygroscopic material having a hygroscopic performance, an adhesive layer, a sealing layer, An organic EL device configured by laminating a stop substrate,
A cushion layer for relieving local stress of the hygroscopic substance is provided between the second electrode layer and the organic filling layer,
The organic filling layer further contains a photocurable material ,
The organic EL device according to claim 1, wherein the cushion layer has a mesh structure .   The organic EL device according to claim 1, wherein the cushion layer contains at least a photocurable material.   The organic EL device according to claim 1, wherein the second electrode layer is covered with the cushion layer, and the cushion layer and the organic filling layer are surrounded by an adhesive layer. .   The organic EL device according to any one of claims 1 to 3, wherein the hardness of the cushion layer is Shore E90 or less including softness below a measurement limit. 5. The organic EL device according to claim 1, wherein the cushion layer has a moisture vapor transmission rate of 50 g / m ² · day or more.   The organic EL device according to claim 1, wherein the cushion layer is made of a water repellent or hydrophobic material.   The organic EL device according to claim 1, wherein the cushion layer is made of a gel-like or rubber-like material. A method of manufacturing an organic EL device having a step of sequentially stacking functional layers on a flat substrate,
At least a step of forming a first electrode layer;
Forming an organic light emitting medium layer including an organic light emitting layer;
Forming a second electrode layer;
Forming an organic filling layer containing a photocurable material and a hygroscopic substance having hygroscopic performance;
Forming a cushion layer between the second electrode layer and the organic filling layer and having a mesh structure and covering the second electrode layer;
Allowing the local stress of the hygroscopic substance to be relaxed by forming an adhesive layer surrounding the organic filling layer and the cushion layer; and
Forming a sealing substrate;
A method for producing an organic EL device, comprising:

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