JPWO2014104102A1 - Organic electroluminescence device manufacturing method and organic electroluminescence device - Google Patents

Abstract

Provided are an organic electroluminescence element manufacturing method and an organic electroluminescence element capable of sufficiently removing minute foreign substances adhering to a base material and preventing impregnation of moisture. The organic electroluminescent element manufacturing method according to the present invention is characterized in that the base material (11) is washed by dry ice blasting using dry ice particles (D) having a particle size of 1 to 200 μm. Moreover, the organic electroluminescent element which concerns on this invention was manufactured by the above-mentioned organic electroluminescent element manufacturing method.

Description

  The present invention relates to an organic electroluminescence element manufacturing method and an organic electroluminescence element.

  Since the organic EL layer constituting the organic electroluminescence (also simply referred to as “organic EL”) element is a very thin film, minute foreign matter adhering to a substrate such as a film causes a leak or the like. In addition, the organic EL layer is weak against moisture, and when impregnated with moisture, the light emission life is shortened, the watermark is generated, the film thickness is changed, the luminance unevenness is increased, and the dark spots are caused by the charge concentration after use over time. May occur.

  In addition to these circumstances, in recent years, improvement in the productivity of organic EL elements is also desired. In order to raise productivity, the process by roll-to-roll conveyance is desirable, and in order to process by roll-to-roll conveyance, it is desirable to use a resin film for the base material. Precision cleaning is necessary to remove the minute foreign matter adhering to the substrate, but wet cleaning impregnates the resin film with water, which may cause the above-mentioned problems, which is not preferable.

As background art of this technical field, for example, there are Patent Documents 1 to 3.
In Patent Document 1, the gas barrier film is dry-cleaned, the dry cleaning is performed by removing foreign matter using an adhesive sheet, the dry cleaning is performed by UV ozone treatment or plasma treatment, and the dry cleaning is performed by an adhesive sheet. It is described that it is carried out by both foreign matter removal using a UV and ozone treatment or plasma treatment.

  Patent Document 2 describes a gas barrier film cleaning method characterized by having at least one dry cleaning step using ultraviolet rays before the wet cleaning step of the gas barrier film.

  Patent Document 3 describes that dry cleaning is performed by foreign matter removal cleaning using an adhesive material.

JP 2009-81124 A JP 2012-67193 A JP 2007-87852 A

  However, the inventions described in Patent Documents 1 and 3 have a problem that the minute foreign matter attached to the base material cannot be sufficiently removed. Further, in the invention described in Patent Document 2, the substrate is impregnated with moisture during wet cleaning, and the light emission life is shortened, the watermark is generated, the film thickness is changed, and the luminance unevenness is increased. Or dark spots may occur due to charge concentration after use over time.

  The present invention has been made in view of the above circumstances, and can sufficiently remove fine foreign substances adhering to a base material, and can prevent impregnation of moisture and an organic electroluminescence element manufacturing method and organic electroluminescence It is an object to provide an element.

The object of the present invention is achieved by the following means.
1. A method for producing an organic electroluminescence device, comprising: performing dry ice blasting using dry ice particles having a particle size of 1 to 200 µm to wash a substrate.
2. 2. The method for producing an organic electroluminescent element according to 1, wherein at least one of ultraviolet irradiation and plasma treatment is performed before the dry ice blasting.
3. 3. The method for producing an organic electroluminescent element according to 1 or 2, wherein the dry ice blasting is performed by roll-to-roll conveyance.
4). An organic electroluminescence device manufactured by the method for manufacturing an organic electroluminescence device according to any one of 1 to 3 above.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to fully remove the micro foreign material adhering to a base material, the organic electroluminescent element manufacturing method and organic electroluminescent element which can prevent a water impregnation can be provided.

It is a schematic diagram explaining a mode that dry ice blasting is performed with the organic EL element manufacturing method which concerns on this embodiment. It is a conceptual sectional view explaining the composition of the organic EL element concerning this embodiment. It is a schematic diagram explaining a mode that an organic EL element is manufactured by roll-to-roll conveyance.

Hereinafter, an organic EL device manufacturing method and an embodiment for carrying out the organic EL device according to the present invention (embodiment) will be described in detail.
First, the organic EL element manufacturing method according to the present invention will be described.

[Organic EL device manufacturing method]
As shown in FIG. 1, the organic EL device manufacturing method according to the present embodiment performs dry ice blasting using dry ice particles D having a particle size of 1 to 200 μm to clean the substrate 11. is there. The substrate 11 may be the one before the electrode (first electrode layer) is formed on the surface of the substrate 11, or after the electrode (first electrode layer 12 (see FIG. 2)) is formed. It may be a thing. FIG. 1 shows a state where dry ice blasting is performed on the base material 11. The substrate 11 will be described in detail later.

Thus, by performing dry ice blasting using the dry ice particles D having a particle size of 1 to 200 μm, it is possible to perform dry cleaning without impregnating the substrate 11 with moisture. By spraying the dry ice particles D on the base material 11, it is possible to remove minute foreign matters attached to the base material 11 by physical action and / or chemical action. The physical action means that the dry ice particles D physically collide with a foreign object. In addition, the chemical action means that when dry ice particles D physically collide with the fine foreign matter, CO ₂ is partially liquefied and behaves like a supercritical fluid to melt the fine foreign matter. .

  When the particle size of the dry ice particles D is less than 1 μm, the particles are too small and the cleaning properties are deteriorated. Therefore, a leak due to minute foreign matters remaining on the surface of the base material 11 occurs. On the other hand, when the particle size of the dry ice particles D exceeds 200 μm, since the particles are too large, damage to the substrate 11 increases. Therefore, the light emission lifetime of the organic EL element is shortened. Considering the damage given to the base material 11, the particle size of the dry ice particles D is preferably 1 to 100 μm. The particle size of the dry ice particles D can be measured by photographing with a high speed camera.

The particle size of the dry ice particles D can be adjusted by changing the setting of the dry ice blasting device. For example, it can be adjusted by changing the ejection speed (flow velocity) and the gas pressure. The flow velocity of the dry ice particles D can be measured with an anemometer. The flow rate of the dry ice particles D can be set to 300 to 400 m / sec, for example.
Examples of the dry ice blasting device that can be used in the present embodiment include a dry ice blasting device described in JP 2010-227741 A.

  The time for performing dry ice blasting can be appropriately changed according to the particle size and flow rate of the dry ice particles D, but is approximately 10 to 30 seconds when the particle size of the dry ice particles D is in the numerical range described above. By doing so, it is possible to sufficiently remove minute foreign matters.

  In this embodiment, it is preferable to perform at least one of ultraviolet irradiation and plasma treatment before performing dry ice blasting. If it does in this way, the fine foreign material containing organic substance can be decomposed | disassembled efficiently.

  The ultraviolet irradiation is preferably performed using a lamp having an emission wavelength of 200 nm or less. Specific examples of such a lamp include a low-pressure mercury lamp (185 nm), a Xe excimer lamp (172 nm), and an Ar excimer lamp (126 nm). Among these, it is preferable to use an Xe excimer lamp from the viewpoint of shortening the processing time, luminous efficiency, and lamp life.

  The atmosphere at the time of ultraviolet irradiation is not particularly limited as long as the desired cleaning can be achieved, but in general, the oxygen concentration is adjusted in order to obtain an effect according to the purpose. It is said that oxygen is excited by ultraviolet rays to generate oxygen active species and ozone in amounts determined by the oxygen concentration, ultraviolet wavelength, and illuminance, and these promote the decomposition of organic foreign matters. When a low-pressure mercury lamp is used, it is preferably performed in the atmosphere (oxygen concentration 21%). However, when vacuum ultraviolet rays such as Xe excimer and Ar excimer are used, oxygen absorption is large and oxygen active species and ozone are high. While it can be generated by concentration, vacuum ultraviolet light cannot reach the gas barrier film surface. In the present invention, irradiation is preferably performed at an oxygen concentration of 0.01 to 5%, more preferably 0.1 to 3%. As the gas other than oxygen in the atmosphere, an inert gas is preferably used. From the viewpoints of cost and discharge voltage, nitrogen gas is preferably used, and dry nitrogen gas is more preferably used.

  The plasma treatment is preferably performed using a radio frequency (RF) plasma apparatus. The atmosphere during the plasma treatment is preferably performed by introducing oxygen gas into the vacuum chamber, adjusting the degree of vacuum to about 6 Pa, and adjusting the RF power to 20 W, but is not limited thereto.

  And in this embodiment, it is preferable to perform the said dry ice blasting by roll-to-roll conveyance. In this way, productivity can be improved reliably. Needless to say, the organic EL element manufacturing method according to the present embodiment is also applicable to roll-to-sheet conveyance.

  In the organic EL element manufactured by the organic EL element manufacturing method according to the present embodiment, almost all the fine foreign matters are removed, so that no leakage due to the fine foreign matters occurs and dry cleaning does not use water. Therefore, it is difficult to shorten the lifetime of light emission due to moisture, and dark spots and luminance unevenness do not occur.

  In the organic EL device manufacturing method according to the present embodiment, after dry ice blasting is performed on the substrate 11 using dry ice particles D having a predetermined particle size, the organic EL device is manufactured using known materials and processes. Can do. Hereinafter, the description will be continued with reference to FIG.

(Base material)
As shown in FIG. 2, the base material 11 is also called a substrate, a transparent substrate, or the like, and is a member that becomes a base of the organic EL element 10. As the base material 11, a synthetic resin having a long belt shape and flexibility, preferably a transparent resin film is used.
Examples of the base material 11 include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane (registered trademark), cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, and cellulose acetate. Cellulose esters such as propionate (CAP), cellulose acetate phthalate, cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, poly Ether ketone, polyimide, polyethersulfone (PES), polyphenylene sulfide, polysulfones Cycloolefin resins such as polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Can be formed.

The base material 11 is preferably formed with a gas barrier film (not shown) that prevents the passage of gas on the surface on which the first electrode layer 12 is formed and / or the back surface thereof. Examples of the gas barrier film include an inorganic film, an organic film, or a hybrid film of both. As a characteristic of the gas barrier film, the water vapor permeability is preferably 0.01 g / m ² · day · atm or less. Furthermore, a high barrier film having an oxygen permeability of 10 ⁻³ ml / m ² / day or less and a water vapor permeability of 10 ⁻⁵ g / m ² / day or less is preferable.

  As a material for forming the gas barrier film, any material may be used as long as it has a function of suppressing intrusion of an element such as moisture or oxygen that causes deterioration of the element. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and organic material layers. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times. The method for forming the gas barrier film is not particularly limited. For example, the vacuum deposition method, the sputtering method, the reactive sputtering method, the molecular beam epitaxy method, the cluster ion beam method, the ion plating method, the plasma polymerization method, the atmospheric pressure plasma polymerization method. A plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used, but an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

(First electrode layer)
The first electrode layer 12 is connected to a power source and functions as, for example, an anode. As such a first electrode layer 12, a material having a work function (4 eV or more) of a metal, an alloy, an electrically conductive compound and a mixture thereof is preferably used. Specific examples of such an electrode substance include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ .ZnO) capable of forming a transparent conductive film may be used. The first electrode layer 12 may be formed by forming a thin film by depositing these electrode materials by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method. (About 100 μm or more), a pattern may be formed through a mask having a desired shape when the electrode material is deposited or sputtered. Or when using the substance which can be apply | coated like an organic electroconductive compound, wet film-forming methods, such as a printing system and a coating system, can also be used. When light emission is taken out from the anode, it is desirable that the transmittance is greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

(Second electrode layer)
The second electrode layer 14 is connected to a power source and functions as, for example, a cathode. As the second electrode layer 14, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Suitable are a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, a lithium / aluminum mixture, aluminum and the like. The second electrode layer 14 can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. Further, the sheet resistance as the second electrode layer 14 is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm. In order to transmit the emitted light, if either the anode (first electrode layer 12) or the cathode (second electrode layer 14) of the organic EL element is transparent or translucent, the emission luminance is improved. It is convenient.

  Moreover, after producing the said metal with the film thickness of 1-20 nm in the 2nd electrode layer 14, by producing the electroconductive transparent material quoted by description of the 1st electrode layer 12 on it, it is transparent or half A transparent second electrode layer 14 (cathode) can be produced, and by applying this, both the first electrode layer 12 (anode) and the second electrode layer 14 (cathode) have transparency. An element can be manufactured.

(Organic EL layer)
The organic EL layer 13 includes a light emitting layer (not shown) that emits light by recombination of holes injected from the anode and electrons injected from the cathode. In addition to the light emitting layer, the organic EL layer 13 includes an electron transport layer, a hole transport layer, a hole injection layer (anode buffer layer), an electron injection layer (cathode buffer layer), a hole blocking layer, an electron blocking layer, and the like ( Any of them can be appropriately laminated.

Examples of the configuration of the organic EL layer 13 include the following.
(1) Light emitting layer (2) Hole transport layer / light emitting layer (3) Light emitting layer / electron transport layer (4) Hole transport layer / light emitting layer / electron transport layer (5) Hole transport layer / light emitting layer / positive Hole blocking layer / electron transport layer (6) hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer (7) anode buffer layer / hole transport layer / light emitting layer / hole blocking layer / Electron transport layer / cathode buffer layer (8) hole transport layer / anode buffer layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer (9) anode buffer layer / hole transport layer / light emitting layer / electron Transport layer / cathode buffer layer

(Light emitting layer)
As described above, the light emitting layer is a layer that emits light by recombination of holes injected from the anode and electrons injected from the cathode. The light emitting layer may be a single layer or may be a multilayer using a plurality of light emitting layers. In the case of a multilayer structure, a non-light emitting intermediate layer may be provided between the light emitting layers. In addition, among the layer configurations, an organic compound layer including a light emitting layer can be used as one light emitting unit, and a plurality of light emitting units can be stacked. The plurality of stacked light emitting units may have a non-light emitting intermediate layer between the light emitting units, and the intermediate layer may further include a charge generation layer. When the light emitting layer is multi-layered, it is necessary to dispose a vapor deposition unit and a coating / drying unit according to the number of layers to be stacked.

  The light emitting layer is made of at least one selected from, for example, a blue light emitting layer, a green light emitting layer, and a red light emitting layer. A white element can be manufactured by stacking the blue light emitting layer, the green light emitting layer, and the red light emitting layer. There is no restriction | limiting in particular as a lamination order in the case of laminating | stacking a light emitting layer. In the present invention, it is preferable that at least one blue light emitting layer is provided at a position closest to the anode in all the light emitting layers. When four or more light emitting layers are provided, for example, blue light emitting layer / green light emitting layer / red light emitting layer / blue light emitting layer, blue light emitting layer / green light emitting layer / red light emitting layer / blue from the order close to the anode. A blue light-emitting layer, a green light-emitting layer, a green light-emitting layer, a red light-emitting layer, a blue light-emitting layer, a green light-emitting layer, and a red light-emitting layer may be stacked in this order. It is preferable for improving luminance stability.

  The total thickness of the light emitting layer is not particularly limited, but is usually selected in the range of 2 nm to 5 μm, preferably 2 to 200 nm in consideration of the uniformity of the film and the voltage required for light emission. Furthermore, it is preferable that it exists in the range of 10-20 nm. A film thickness of 20 nm or less is preferable because it has the effect of improving the stability of the emission color with respect to the driving current as well as the voltage surface. The thickness of each light emitting layer is preferably selected in the range of 2 to 100 nm, and more preferably in the range of 2 to 20 nm. Although there is no restriction | limiting in particular about the film thickness relationship of each light emitting layer of blue, green, and red, It is preferable that the blue light emitting layer (the sum total when there are two or more layers) is the thickest among three light emitting layers.

  The light emitting layer includes at least three layers having different emission spectra, each having an emission maximum wavelength in the range of 430 to 480 nm, 510 to 550 nm, and 600 to 640 nm. If it is three or more layers, there will be no restriction | limiting in particular. When there are more than four layers, there may be a plurality of layers having the same emission spectrum. A layer having an emission maximum wavelength in the range of 430 to 480 nm is referred to as a blue light emitting layer, a layer in the range of 510 to 550 nm is referred to as a green light emitting layer, and a layer in the range of 600 to 640 nm is referred to as a red light emitting layer. Moreover, in the range which maintains the said maximum wavelength, you may mix a several luminescent compound in each light emitting layer. For example, the blue light emitting layer may be used by mixing a blue light emitting compound having a maximum wavelength of 430 to 480 nm and a green light emitting compound having the same wavelength of 510 to 550 nm.

The material (light emitting material) that can be used for the light emitting layer is not particularly limited. For example, Toray Research Center, Inc. The latest trend of flat panel displays The current state of EL displays and the latest technological trends Various materials as described on pages 228 to 332 Can be mentioned.
In addition, in the organic EL element 10 which concerns on this invention, even if it is a low molecular light-emitting material, it can be used conveniently. A low-molecular light-emitting material refers to a light-emitting material having a weight average molecular weight of 5000 or less, preferably 3000 or less, more preferably 2000 or less. In addition, a high-molecular light-emitting material having a weight average molecular weight larger than 5000 can also be suitably used.

  The light emitting layer can be formed by a vapor deposition method performed by arranging an arbitrary vapor deposition source in a vacuum film formation chamber. Examples of the vapor deposition method include a sputtering method, a mask vapor deposition method, and a photolithography patterning method. The light emitting layer can also be formed by applying a light emitting layer forming coating solution and drying. As described above, the light emitting layer is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron injection layer, or the hole transport layer. The portion that emits light may be within the layer of the light emitting layer or at the interface between the light emitting layer and the adjacent layer.

  Here, as a wet coating machine for applying the light emitting layer forming coating solution, for example, a die coating method, a screen printing method, a flexographic printing method, an ink jet method, a Mayer bar method, a cap coating method, a spray coating method, a casting method, a roll An applicator used for a coating method, a bar coating method, a gravure coating method, or the like can be used. The use of these wet coaters can be appropriately selected according to the material of the organic compound layer.

(Hole transport layer (hole injection layer, electron blocking layer))
The hole transport layer has a role of moving holes to an effective recombination region and a role of blocking electrons locally as an energy barrier to strengthen light emission. The hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers. These are described in detail in “Organic EL devices and their forefront of industrialization” (issued on November 30, 1998 by NTS).

  The hole transport material has any of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

  The above-mentioned materials can be used as the hole transport material, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound. Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ', N'-tetraphenyl-4,4'-diaminophenyl; N, N'-diphenyl-N, N'- Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4'-N, N-diphenylaminostilbenzene; N-phenylcarbazole, as well as two of those described in US Pat. No. 5,061,569 Having a condensed aromatic ring in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-308 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 88 are linked in a starburst type ( MTDATA) and the like.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

  JP-A-11-251067, J. Org. Huang et. al. It is also possible to use so-called p-type hole transport materials as described in the literature (Applied Physics Letters 80 (2002), p. 139). In the present invention, it is preferable to use these materials because a light-emitting element with higher efficiency can be obtained.

  Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5-200 nm. This hole transport layer may have a single layer structure composed of one or more of the above materials. Alternatively, a hole transport layer having a high p property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like. It is preferable to use a hole transport layer having such a high p property because an organic EL element with lower power consumption can be produced.

(Electron transport layer (electron injection layer, hole blocking layer))
The electron transport layer has a role of moving electrons to an effective recombination region and a role of blocking holes as an energy barrier and locally retaining light to enhance light emission. The electron transport layer is made of a material having a function of transporting electrons (electron transport material), and includes an electron injection layer and a hole blocking layer in a broad sense. The electron transport layer can be provided as a single layer or a plurality of layers. These are described in detail in “Organic EL devices and their forefront of industrialization” (issued on November 30, 1998 by NTS).

  Conventionally, it is used for an electron transport layer adjacent to the light-emitting layer on the cathode side when the electron transport material (also serves as a hole blocking material) used for a single electron transport layer or a plurality of electron transport layers are used. Any electron transporting material may be used as long as it has a function of transmitting electrons injected from the cathode to the light emitting layer, and any of known materials can be selected and used as the material. . Examples include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane, anthrone derivatives, and oxadiazole derivatives. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron-withdrawing group can also be used as a material for the electron transport layer. it can. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq ₃ ), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) Aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and the central metals of these metal complexes are In, Mg Metal complexes replaced with Cu, Ca, Sn, Ga, or Pb can also be used as the material for the electron transport layer.

  In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the material for the electron transport layer. Further, distyrylpyrazine derivatives exemplified as the material of the light emitting layer can also be used as the material of the electron transport layer, and n-type-Si, n-type-SiC, etc. as well as the hole injection layer and the hole transport layer. These inorganic semiconductors can also be used as a material for the electron transport layer.

The electron transport layer can be formed by thinning the above material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an inkjet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.
In addition, the electron transport layer can be doped with impurities to increase the n property. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like. Furthermore, in the present invention, the electron transport layer may contain potassium or a potassium compound. As the potassium compound, for example, potassium fluoride can be used. Thus, it is preferable to increase the n property of the electron transport layer because an element with lower power consumption can be manufactured.

  The details of the electron injection layer (cathode buffer layer) are also described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium, aluminum, etc. Metal buffer layer typified by lithium, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide, etc. . The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm although it depends on the material.

  The hole blocking layer has a function of an electron transport layer in a broad sense. The hole blocking layer is made of a hole blocking material that has a function of transporting electrons but has a very small ability to transport holes, and recombines electrons and holes by blocking holes while transporting electrons. Probability can be improved. The hole blocking layer can be implemented using the one described in the electron transport layer. The hole blocking layer is preferably provided adjacent to the light emitting layer. The film thickness of the hole blocking layer is preferably 3 to 100 nm, more preferably 5 to 30 nm.

(Sealing)
On the 2nd electrode layer 14, it seals using the sealing layer or the sealing film (all are not shown in figure).
As the sealing film to be used, a barrier film and a metal film made of the same material as the gas barrier film can be used. For example, the sealing film can be bonded to the substrate 11 with an adhesive. Specific examples of the adhesive include photo-curing and thermosetting adhesives having reactive vinyl groups such as acrylic acid oligomers and methacrylic acid oligomers, moisture-curing adhesives such as 2-cyanoacrylates, and epoxy. Heat- and chemical-curing type (two-component mixed) adhesives such as polyamide-based, polyamide-based, polyester-based, polyolefin-based hot-melt adhesives, and cationic-curing type UV-curable epoxy resin adhesives it can.

  In addition, since the organic EL layer 13 which comprises the organic EL element 10 may deteriorate with heat processing, what can be adhesively cured from room temperature to 80 degreeC is preferable. A desiccant may be dispersed in the adhesive. Application | coating of the adhesive agent to a sealing part may use commercially available dispenser, and may print it like screen printing.

  In the case of forming the sealing layer, it can be formed on the second electrode layer 14 by using the materials and methods described in the gas barrier film of the substrate 11.

  In the gap between the sealing member (sealing layer, sealing film) and the display area of the organic EL element 10, in the gas phase and liquid phase, inert gas such as nitrogen and argon, fluorinated hydrocarbon, silicon oil It is preferable to inject an inert liquid such as A vacuum can also be used. Moreover, a hygroscopic compound can also be enclosed inside. Examples of the hygroscopic compound include metal oxides (eg, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide), sulfates (eg, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate, etc.). Metal halides (eg, calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchloric acids (eg, barium perchlorate, In particular, anhydrous salts are preferably used in sulfates, metal halides and perchloric acids.

  In the light emitting layer constituting the organic EL layer 13 in the organic EL element 10, a known host compound and a known phosphorescent compound (also referred to as a phosphorescent compound) are used to increase the light emission efficiency of the light emitting layer. It is preferable to contain.

  The host compound is a compound contained in the light-emitting layer, the mass ratio in the layer is 20% or more, and the phosphorescence quantum yield of phosphorescence emission is 0.1 at room temperature (25 ° C.). Is defined as less than a compound. The phosphorescence quantum yield is preferably less than 0.01. A plurality of host compounds may be used in combination. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. In addition, by using a plurality of phosphorescent compounds, it is possible to mix different light emission, thereby obtaining an arbitrary emission color. White light emission is possible by adjusting the kind of phosphorescent compound and the amount of doping, and can also be applied to illumination and backlight.

  As these host compounds, compounds having a hole transporting ability and an electron transporting ability, preventing emission light from being increased in wavelength, and having a high Tg (glass transition temperature) are preferable. Known host compounds include, for example, JP-A Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, and 2002-334786. Gazette, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645 2002-338579, 2002-105445, 2002-343568, 2002-141173, 2002-352957, 2002-203683, 2002-363227 2002-231453, 2003-3165, 2002-234888, 2003-27048, 2002-255934, 2002-260861, 2002-280183, Examples thereof include compounds described in 2002-299060, 2002-302516, 2002-305083, 2002-305084, 2002-308837 and the like.

  In the case of having a plurality of light emitting layers, it is preferable that 50% by mass or more of the host compound in each layer is the same compound because it is easy to obtain uniform film properties over the entire organic EL layer 13, and further, the host compound It is more preferable that the phosphorescence emission energy of is 2.9 eV or more because it is advantageous in efficiently suppressing energy transfer from the dopant and obtaining high luminance. Phosphorescence emission energy means the peak energy of the 0-0 band of the phosphorescence emission when a host compound is formed as a deposited film with a thickness of 100 nm on a substrate and the photoluminescence is measured.

  The host compound has a phosphorescence emission energy of 2.9 eV or more and a Tg of 90 ° C. or more in consideration of deterioration of the organic EL element 10 over time (decrease in luminance, film property deterioration), market needs as a light source, etc. It is preferable that That is, in order to satisfy both luminance and durability, it is preferable that phosphorescence emission energy is 2.9 eV or more and Tg is 90 ° C. or more. Tg is more preferably 100 ° C. or higher.

  A phosphorescent compound (phosphorescent compound) is a compound in which light emission from an excited triplet is observed, is a compound that emits phosphorescence at room temperature (25 ° C.), and has a phosphorescence quantum yield of 25. The compound is 0.01 or more at ° C. By using it together with the host compound described above, the organic EL device 10 with higher luminous efficiency can be obtained.

  The phosphorescent compound in the present invention preferably has a phosphorescence quantum yield of 0.1 or more. The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence quantum yield used in the present invention only needs to achieve the above phosphorescence quantum yield in any solvent.

  There are two types of light emission of the phosphorescent compound in principle. One is the recombination of the carrier on the host compound to which the carrier is transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent compound. The energy transfer type is to obtain light emission from the phosphorescent compound by moving to the other, and the other is that the phosphorescent compound becomes a carrier trap, and carrier recombination occurs on the phosphorescent compound, and the phosphorescent compound emits light. Although it is a carrier trap type in which light emission is obtained, in any case, it is a condition that the excited state energy of the phosphorescent compound is lower than the excited state energy of the host compound.

  The phosphorescent compound can be appropriately selected from known compounds used for the light emitting layer of the organic EL element 10. The phosphorescent compound is preferably a complex compound containing a group 8-10 metal in the periodic table of elements, more preferably an iridium compound, an osmium compound, or a platinum compound (platinum complex compound), rare earth Of these, iridium compounds are the most preferred.

  In the present invention, the phosphorescence emission maximum wavelength of the phosphorescent compound is not particularly limited, and can be obtained in principle by selecting a central metal, a ligand, a ligand substituent, and the like. The emission wavelength can be changed.

  The light emission color of the organic EL device 10 of the present invention and the compound according to the present invention is shown in FIG. 4.16 on page 108 of “New Color Science Handbook” (edited by the Japan Color Society, University of Tokyo Press, 1985). It is determined by the color when the result measured with a luminance meter CS-1000 (manufactured by Konica Minolta Optics) is applied to the CIE chromaticity coordinates.

The white element referred to in the present invention means that the chromaticity in the CIE 1931 color system at 1000 cd / m ² is X = 0.33 ± 0.07 when the front luminance at 2 ° viewing angle is measured by the above method. It is in the region of Y = 0.33 ± 0.07.

  The external extraction efficiency at room temperature of light emission of the organic EL device 10 of the present invention is preferably 1% or more, more preferably 5% or more. Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element 10 / the number of electrons sent to the organic EL element 10 × 100.

  In addition, a hue improvement filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element 10 into multiple colors using a phosphor may be used in combination. In the case of using a color conversion filter, the λmax of light emission of the organic EL element 10 is preferably 480 nm or less.

  The organic EL device 10 of the present invention preferably uses the following method in combination in order to efficiently extract light generated in the light emitting layer. Generally, an organic EL element emits light inside a layer having a refractive index higher than that of air (refractive index is about 1.7 to 2.1), and about 15% to 20% of light generated in the light emitting layer. It is said that only the light can be extracted. This is because light incident on the interface (interface between the transparent substrate and air) at an angle θ greater than the critical angle causes total reflection and cannot be taken out of the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the side surface of the device.

  As a method for improving the light extraction efficiency, for example, a method of forming irregularities on the transparent substrate surface to prevent total reflection at the interface between the transparent substrate and the air (US Pat. No. 4,774,435). A method for improving efficiency by imparting a light collecting property to a substrate (Japanese Patent Laid-Open No. 63-134795). A method of forming a reflective surface on the side surface of an element (Japanese Patent Laid-Open No. 1-220394). A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between a substrate and a light emitter (Japanese Patent Laid-Open No. 62-172691). A method of introducing a flat layer having a lower refractive index than the substrate between the base material and the light emitter (Japanese Patent Laid-Open No. 2001-202827). There is a method of forming a diffraction grating between any one of the substrate, the transparent electrode layer and the light emitting layer (including between the substrate and the outside) (Japanese Patent Laid-Open No. 11-283951).

  In the present invention, these methods can be used in combination with the organic EL element 10, but a method of introducing a flat layer having a lower refractive index than the base material between the base material and the light emitting layer, or a base material, A method of forming a diffraction grating between any layers of the transparent electrode layer and the light emitting layer (including between the substrate and the outside) can be suitably used. In the present invention, by combining these means, it is possible to obtain an element having higher brightness or durability.

  When a low refractive index medium is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light extracted from the transparent electrode has a higher extraction efficiency to the outside as the refractive index of the medium is lower. . Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Further, it is preferably 1.35 or less. The thickness of the low refractive index medium is preferably at least twice the wavelength in the medium. This is because the effect of the low refractive index layer is diminished when the thickness of the low refractive index medium is about the wavelength of light and the electromagnetic wave that has exuded by evanescent enters the substrate. The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving light extraction efficiency. This method is generated from the light emitting layer by utilizing the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction such as first-order diffraction or second-order diffraction. Of the light, the light that cannot go out due to total reflection between layers, etc. is diffracted by introducing a diffraction grating in any layer or medium (inside a transparent substrate or transparent electrode) It tries to take out light. The introduced diffraction grating desirably has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction is diffracted. The light extraction efficiency does not increase so much. However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and light extraction efficiency is increased.

  As described above, the position where the diffraction grating is introduced may be in any of the layers or in the medium (in the transparent substrate or in the transparent electrode), but is preferably in the vicinity of the light emitting layer where light is generated. At this time, the period of the diffraction grating is preferably about 1/2 to 3 times the wavelength of light in the medium. The arrangement of the diffraction gratings is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

  Furthermore, the organic EL element 10 of the present invention is processed so as to provide, for example, a structure on the microlens array on the light extraction side of the base material in order to efficiently extract the light generated in the light emitting layer, or so-called By combining with a condensing sheet, it can condense in a specific direction, for example, a front direction with respect to the element light emitting surface. Thereby, the brightness | luminance in a specific direction can be raised. As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 μm to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

  As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used. As the shape of the prism sheet, for example, a substrate may be formed with a Δ-shaped stripe having an apex angle of 90 degrees and a pitch of 50 μm, or the apex angle is rounded and the pitch is changed randomly. Other shapes may be used. Moreover, in order to control the light emission angle from a light emitting element, you may use together a light diffusing plate and a film with a condensing sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

(Manufacturing by roll-to-roll conveyance)
The organic EL element 10 according to the first embodiment described above can perform most of the steps by roll-to-roll conveyance. Hereafter, with reference to FIG. 3, a mode that the organic EL element 10 is manufactured by roll-to-roll conveyance is demonstrated. FIG. 3 is a schematic diagram illustrating a configuration example of a series of manufacturing apparatuses 100 that manufacture organic EL elements used for illumination.

  The manufacturing apparatus 100 includes an unwinding chamber 110 for unwinding the substrate 11 from a flexible belt-shaped substrate roll 11c (hereinafter simply referred to as “roll 11c”) on which the first electrode layer 12 (anode) is formed, A mechanism that does not cause a positional shift in a direction perpendicular to the transport direction of the base material 11, a transport auxiliary chamber 120 in which a movement distance correction mechanism in the transport direction, and the like are disposed.

  In addition, the manufacturing apparatus 100 is provided with a first film forming chamber 130 for depositing a material constituting each functional layer such as the organic EL layer 13 on the base material 11, and a transport having the same configuration as the transport auxiliary chamber 120. An auxiliary chamber 140 and a second film forming chamber 150 for forming another functional layer on the functional layer formed in the first film forming chamber 130 are provided.

  Furthermore, the manufacturing apparatus 100 affixes a transfer auxiliary chamber 160 having the same configuration as the transfer auxiliary chambers 120 and 140 and a protective film 172 from a roll 171 for protecting the film formed on the substrate 11. Laminating chamber 170.

  Further, the manufacturing apparatus 100 includes a transfer auxiliary chamber 180 having the same configuration as the transfer auxiliary chambers 120, 140, and 160, and an organic EL sheet 11e (organic EL element 10) obtained by laminating a protective film 172. A winding chamber 190 that winds around the roll 11d.

  Here, for simplification of description, the number of chambers in which the functional layers are formed is two chambers, the first deposition chamber 130 and the second deposition chamber 150. However, this can be changed as appropriate according to the number and type of functional layers to be formed.

  In each of the above-described chambers 110 to 190, in this embodiment, the atmosphere is controlled according to the processing performed in the chamber. Specifically, the first film formation chamber 130 and the second film formation chamber 150 in which the functional layer is formed are in a vacuum. Further, the auxiliary transfer chambers 120, 140, 160, and 180 in which the base material 11 is transferred are also in a vacuum. The laminating chamber 170 has an inert atmosphere (for example, under nitrogen gas). Further, the unwinding chamber 110 and the winding chamber 190 are under the atmosphere.

  The base material 11 unwound from the roll 11c is changed in the traveling direction by a plurality of rolls and is given an appropriate tension until it is wound around the roll 11d via the respective chambers 110 to 190. The number of installations and installation positions of a plurality of rolls can be arbitrarily set.

  The core of the roll 11c provided in the unwind chamber 110 and the core of the roll 11d provided in the take-up chamber 190 are not deformed when the substrate 11 is taken up, and the atmosphere is about 150 ° C. Those that do not deform even when exposed are preferred. Further, it is preferable that the winding core does not generate dust when being attached to and detached from the manufacturing apparatus 100 or transferred to the decompression chamber or the like. Furthermore, it is preferable that the part which the base material 11 touches is smooth among the surface parts of a winding core, and specifically, it is preferable that surface roughness Ra is 30 nm or less, and Rt is 100 nm or less. The material of the winding core is preferably glass fiber reinforced plastic or stainless steel.

  Furthermore, in order to prevent the web surface on the core and the back surface of the web overlapping therewith from rubbing against each other at both ends in the axial direction of the winding core of the base material 11, You may give a knurling process (it is also called embossing). This height is preferably about 2 to 50 μm, for example.

  Hereinafter, it demonstrates in order. First, the base material 11 is unwound from a roll 11 c installed in the unwinding chamber 110. As already described, anode (electrode) patterning may be performed on the base material 11 in advance.

  The base material 11 unwound from the roll 11 c is cleaned by dry ice blasting using dry ice particles D having a particle size of 1 to 200 μm before entering the first film forming chamber 130. Although FIG. 3 shows a state in which the dry ice blasting device 111 is provided in the unwinding chamber 110 and the base material 11 is cleaned, the present invention is not limited to this. A blasting device 111 can also be provided.

  The base material 11 cleaned by dry ice blasting is transferred to the first film forming chamber 130 via the transfer auxiliary chamber 120. Then, the transported base material 11 is stopped at a predetermined position in the first film formation chamber 130, and a functional layer is formed (that is, film formation) in the first film formation chamber 130.

  As shown in FIG. 3, the functional layer is formed at a predetermined position in the first film forming chamber 130 by a vapor deposition source 131 from which a vapor deposition material for forming the functional layer is released, and the vapor deposition source 131 and the base layer. A fine-tunable pattern forming mask 132 (hereinafter referred to as “mask 132”) for forming a functional layer having a desired pattern is disposed between the material 11 and the material 11. Further, a temperature adjustment plate 133 for maintaining the temperature of the base material 11 during vapor deposition is disposed at a position facing the mask 132 with the base material 11 interposed therebetween.

  Deposition on the substrate 11 is performed as follows. That is, first, the vapor deposition source 131 is adjusted and maintained so that the vapor deposition material is discharged at a predetermined vapor deposition rate, and is blocked by a shutter (not shown) or the like so as not to adhere to the base material 11 unintentionally. Yes. The substrate 11 is marked with an alignment mark (not shown). The first film forming chamber 130 is provided with a camera (not shown) and the like for reading the marks. Thereby, the base material 11 stops after being conveyed at an arbitrary speed to a predetermined position where the camera can read the alignment mark.

  Next, the alignment mark is read by the camera, and the mask 132 is finely adjusted to match the position of the alignment mark. Thereafter, while the temperature adjustment plate 133 approaches the base material 11 and comes into close contact, the mask 132 also comes close to the base material 11 and stops at a position where it comes into close contact or has a slight gap.

  Then, the shutter of the vapor deposition source 131 is opened, and the functional layer is formed in a pattern on the substrate 11. At this time, the deposition time and the like are controlled so that the determined film thickness is obtained, and the shutter is closed when the determined film thickness is obtained. Thereafter, while the mask 132 is separated from the substrate 11 and returned to the reference position, the temperature adjustment plate 133 is also separated from the substrate 11 and returned to the reference position. Thereafter, the conveyance of the base material 11 is resumed.

  When the transfer is resumed, the substrate 11 is transferred to the second film formation chamber 150 via the transfer auxiliary chamber 140. Then, in the second film formation chamber 150, metal deposition is performed in the same manner as the film formation in the first film formation chamber 130, and a cathode is formed. That is, a process of forming a cathode is performed on the base material 11.

  Thereafter, the base material 11 on which the functional layer and the cathode are formed is sent to the laminating chamber 170 through the auxiliary conveyance chamber 160. In the laminating chamber 170, the protective film 172 is attached so as to cover the cathode surface while the base material 11 is conveyed. Thereby, the organic EL sheet 11e is obtained. And the organic EL sheet 11e obtained by laminating is conveyed to the winding chamber 190 via the conveyance auxiliary chamber 180, and is wound up by the roll 11d. Finally, the organic EL element 10 is obtained by unwinding from the roll 11d as necessary and cutting it into a predetermined size.

  In the above description, the case where the organic EL element is manufactured by roll-to-roll conveyance has been described. However, after the organic EL sheet 11e is obtained, the roll-to-sheet conveyance is performed in a sheet-like state by cutting or the like. Needless to say, the substrate 11 can be cleaned by dry ice blasting using dry ice particles D having a particle size of 1 to 200 μm.

  Hereinafter, the content of the present invention will be specifically described with reference to an example that exhibits the effect of the present invention and a comparative example that is not.

<Production of organic EL element>
An organic EL element was manufactured using the manufacturing apparatus 100 shown in FIG.
First, a gas barrier layer having a thickness of 80 nm was formed on a strip-like polyethylene terephthalate film (PET film) having a width of 1000 mm and a thickness of 100 μm by plasma under atmospheric pressure according to a conventional method. Further, a transparent conductive film (first electrode layer) made of ITO having a thickness of 130 nm was formed on the gas barrier layer in an argon atmosphere. The size of the transparent conductive film was 280 mm as the length in the transport direction and 280 mm as the length (width direction) perpendicular to the transport direction. The surface specific resistance of this transparent conductive film was 40Ω / □.

  Next, on the transparent conductive film, a photolithographic resin that was polymerized with ultraviolet light was applied in a rectangular region having a width direction of 670 mm and a longitudinal direction of 720 mm, and passed through a drying oven at 90 ° C. After aligning with the transparent electrode film, exposing, transporting, developing, etching, alkali treatment, washing with ion-exchanged water, blowing with clean air, and then winding it around the winding shaft It was. Thereby, the roll 11c by which the film which gave the electrode pattern of ITO on the PET film surface was wound was obtained. The distance between the electrode patterns was set at a distance of 60 mm in order to secure in advance a portion sandwiched between gates for forming a differential pressure in each chamber of the manufacturing apparatus 100.

  The obtained roll 11c was set in the unwinding chamber 110 of the manufacturing apparatus 100 shown in FIG. 3, applied with tension to the base material 11 of the roll 11c, and started to operate the manufacturing apparatus 100.

Various cleanings including dry ice blasting shown in Table 1 were performed on the base material 11 unwound from the roll 11c.
The dry ice blasting was performed so that the particle size (mode) of the dry ice particles was adjusted to the size shown in Table 1 described later. The dry ice blasting was performed under the condition that the flow rate of dry ice particles was 350 m / sec and the cleaning time was 30 seconds.
As the adhesive sheet, a cleaning roller manufactured by TECNEC was used.
The UV was performed under the condition that excimer UV (172 nm) was irradiated for 30 sec under 35 mW / cm ² conditions.
The plasma was performed under the conditions of 13.56 MHz, 50 W, 0.3 mmHg, and an oxygen gas flow rate of 20 mL / min.
The wet cleaning was performed under the condition that after immersion ultrasonic cleaning using an alkaline detergent, immersion ultrasonic cleaning with ultrapure water was performed and drying was performed with an air knife.

Subsequently, the material which comprises a functional layer was vapor-deposited in the 1st film-forming chamber 130 shown in FIG. As the deposited material, α-NPD (thickness 40 nm), CBP (containing 6 mass% of Ir (ppy) ₃ as a co-deposition component) (thickness 35 nm), BAlq (thickness 5 nm), Alq ₃ (thickness) 40 nm) and lithium fluoride (thickness 0.5 nm), which were deposited on the substrate 11 in this order. The structural formula of the material used for vapor deposition is shown below.

  Next, 110 nm of aluminum was deposited in the second film formation chamber 150. In the formation of the electrode in the second film formation chamber 150, the material constituting the functional layer was deposited in the same manner as the formation of the functional layer in the first film formation chamber 130.

  Then, in the laminating chamber 170, a PET film having a gas barrier layer applied with a sealing resin (adhesive) having a thickness of 40 μm (80 μm as the thickness of the PET film) was laminated in a nitrogen stream. The gas barrier layer formed on the PET film is the same as the gas barrier layer formed on the PET film wound around the roll 11c. Thereby, the organic EL sheet 11e is obtained, and the obtained organic EL sheet 11e is wound around the roll 11d in the winding chamber 190 and emits green phosphorescence. Organic EL elements according to 1 to 11 were produced.

  No. produced Using the organic EL elements according to 1 to 11, the light emission uniformity (luminance unevenness), leakage current characteristics, and half-life / dark spot (DS) with time were evaluated. Evaluation of light emission uniformity (luminance unevenness), leakage current characteristics, half-life and time-lapse DS was performed as follows.

(Emission uniformity)
For light emission uniformity, a KEITHLEY source measure unit 2400 type was used to apply a DC voltage to the organic EL element to emit light. No. 1 emitted at 1000 cd / m ² . About the organic EL element which concerns on 1-11, each light emission luminance nonuniformity was observed with the 50 time microscope. No. After heating the organic EL elements according to 1 to 11 in an oven at 60% RH and 80 ° C. for 2 hours, and then adjusting the humidity again in the environment of 23 ± 3 ° C. and 55 ± 3% RH for 1 hour or more, similarly Luminescence uniformity was observed.

(Evaluation rank of light emission uniformity)
○: Uniform light emission, no problem.
(Triangle | delta): Although light emission nonuniformity is seen partially, it is permissible.
X: Uneven light emission is observed over the entire surface, which is not acceptable.

(Leakage current characteristics)
Using a constant voltage power source, a reverse voltage (reverse bias) of 5 V was applied for 5 seconds, and the current flowing through the organic EL element at that time was measured. No. Measurement was performed for 10 light emitting regions for each of the organic EL elements according to 1 to 11, and the maximum current value was set as a leakage current, which was used as a substitute characteristic of leakage.

(Leakage current characteristic evaluation rank)
○: Maximum current value is less than 1 × 10 ⁻⁵ A Δ: Maximum current value is 1 × 10 ⁻⁵ A or more, less than 1 × 10 ⁻³ A ×: Maximum current value is 1 × 10 ⁻³ A or more

(Half life / Time DS)
The drive life was evaluated according to the following method using a drive life evaluation apparatus prepared by combining the produced organic EL element with a commercially available constant current power supply and a spectral radiance meter (CS-2000 manufactured by Konica Minolta). .

A current of 10 mA / cm ² was applied to each organic EL element, and the change in luminance over time was measured with a spectral radiance meter. Next, each organic EL element when the luminance of each organic EL element is half the lifetime immediately after driving is defined as a half-life, and the lifetime of the organic EL element fabricated on the glass substrate is defined as 100. The relative lifetime was obtained and used as a measure of the driving lifetime.
Similarly, the ratio of the total area of the DS (dark spots) with respect to the light emission area in the same test at the current application time of 100 h was also evaluated.

(Evaluation rank for half-life and time-lapse DS)
○: Relative life of 80 or more and DS area ratio within 0.1% Δ: Relative life of 70 or more and DS area ratio within 0.3% ×: Relative life of 70 or less or DS area ratio of 0.3% that's all

  Evaluation results of emission uniformity (luminance unevenness), leakage current characteristics, and half-life / time-lapse DS are No. It shows with the washing | cleaning conditions of the organic EL element concerning 1-11. In Table 1, “-” indicates that the evaluation of leakage current characteristics was poor, and therefore it was judged that there was no need to evaluate the light emission uniformity, half-life, and time-lapse DS, and evaluation was not performed.

  As shown in Table 1, no. The organic EL elements according to 6 to 9 sufficiently clean the substrate with dry ice blast and sufficiently remove the fine foreign matter adhering to the substrate because the dry ice particles used in the dry ice blast had an appropriate particle size. Moreover, since the base material was washed by dry ice blasting, moisture was not impregnated in the functional layer formed thereafter. As a result, the evaluation results of light emission uniformity, leakage current characteristics, and half-life / time-lapse DS were all excellent (◯).

On the other hand, no. In the organic EL elements according to 1 to 3, since the cleaning method was not dry ice blasting, the evaluation result of the leakage current characteristics was bad (×). No. In the organic EL device according to No. 4, since the cleaning method was wet cleaning, the substrate and the organic EL layer were impregnated with moisture, and the evaluation results of the light emission uniformity, half-life and time-lapse DS were poor (×).
No. In the organic EL device according to No. 5, although the cleaning method was dry ice blasting, the particle size of the dry ice particles was too small, so that the removal of minute foreign matters was not sufficiently performed, and the evaluation result of the leakage current characteristics was poor (× ).
No. The organic EL devices according to 10 and 11 had a dry ice blast cleaning method, but the dry ice particle size was too large, so that the evaluation results of half-life and time-lapse DS were poor (×).

No. except that the cleaning time by dry ice blasting was reduced from 30 seconds to 10 seconds. No. 7 produced under the same conditions as in No. 7. No. 12 and the cleaning time by dry ice blasting were reduced from 30 seconds to 10 seconds, and Xe excimer lamp having a wavelength of 172 nm was irradiated for 30 seconds under the condition of 35 mW / cm ² before dry ice blasting. 13 was used to evaluate leakage current characteristics under the same conditions as described above. As a result, no. The organic EL device according to No. 13 is No. 13. The leakage current characteristics were superior to those of the organic EL device according to No. 12.
From this, it was confirmed that cleaning by dry ice blasting can be performed more effectively by UV irradiation. This is considered to be due to the fact that minute foreign substances including organic substances can be efficiently decomposed by UV irradiation. Further, from this, it is considered that a similar result can be obtained by performing a plasma treatment capable of efficiently decomposing minute foreign matters including organic matter prior to dry ice blasting.

D Dry ice particles 10 Organic electroluminescence device (organic EL device)
DESCRIPTION OF SYMBOLS 11 Base material 12 1st electrode layer 13 Organic electroluminescent layer 14 2nd electrode layer

Claims (4)

A method for producing an organic electroluminescence device, comprising:
A method for producing an organic electroluminescence device, comprising performing dry ice blasting using dry ice particles having a particle diameter of 1 to 200 µm to wash a substrate.   The method for producing an organic electroluminescent element according to claim 1, wherein at least one of ultraviolet irradiation and plasma treatment is performed before the dry ice blasting.   The method for producing an organic electroluminescence element according to claim 1, wherein the dry ice blasting is performed by roll-to-roll conveyance.   An organic electroluminescence device manufactured by the method for manufacturing an organic electroluminescence device according to any one of claims 1 to 3.

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