JP2007265850A - Method and device of manufacturing organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device of manufacturing an organic EL element capable of obtaining an organic EL element having a uniform luminance in the element. <P>SOLUTION: Before manufacture of an organic EL element, luminance distribution in the substrate of an element manufactured by a test vapor deposition is measured, and based on the result, the position of the substrate at the time of vapor deposition is adjusted and the thickness of an organic layer being the luminous layer is adjusted. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  As a light emitting element used for a display device, an electroluminescence element (hereinafter referred to as an EL element) is known. This EL element is classified into an organic EL element using an organic material as a light emitting layer and an inorganic EL element using an inorganic material as a light emitting layer. Among these, the organic EL element has a configuration in which an organic layer composed of one or more layers containing an organic material is sandwiched between a cathode and an anode. When a voltage is applied between the cathode and the anode, electrons are injected from the cathode and holes are injected from the anode into the organic layer to recombine to generate excitons. The organic EL element is a light emitting element utilizing light emission (fluorescence or phosphorescence) when the exciton is deactivated.

  In order to drive the inorganic EL element, an alternating high voltage is required, whereas the organic EL element can emit light at a voltage of about several volts to several tens of volts. Furthermore, the organic EL element has many advantages such as being self-luminous and having a wide viewing angle, high visibility, and being a thin-film type complete solid-state element that can easily save space and improve portability. In recent years, it has attracted particular attention.

  Another major feature of the organic EL element is that it is a surface light emitting element, unlike main light sources that have been conventionally used in practice, such as light emitting diodes and cold cathode tubes. One application that can effectively utilize this characteristic is a display backlight. In particular, in recent years, it is also suitable as a backlight for liquid crystal full-color displays, for which demand has increased significantly. Thus, when using an organic EL element as a backlight for a display, it is calculated | required that emission luminance is as uniform as possible in a surface.

  On the other hand, as an organic EL element manufacturing method, a vapor deposition method, an ink jet coating method, a flexographic printing method, and the like have been proposed. Among them, the vapor deposition method is mainly used because it is easy to sequentially stack an organic layer (a hole transport layer, a light emitting layer, an electron transport layer, etc.) composed of one layer or a plurality of layers on a substrate. Widely used. Above all, a so-called roll-to-roll method is very productive, in which a belt-like substrate using a flexible base material such as a resin film is unwound from a roll and wound up on a roll after forming an organic layer or electrode. It is highly attractive and has attracted particular attention (see, for example, Patent Document 1).

However, when manufacturing an organic EL element by a vapor deposition method, the film thickness of the organic layer which is a light emitting layer may become non-uniform | heterogenous. If the film thickness of the organic layer which is a light emitting layer becomes non-uniform | heterogenous, it will become a problem since the light emission luminance of an organic EL element becomes non-uniform | heterogenous. For this reason, a method has been proposed in which the substrate is rotated during vapor deposition to keep the film thickness in the substrate constant (see, for example, Patent Document 2). In addition, a method of making the film thickness in the substrate constant by optimizing the arrangement of a plurality of vapor deposition sources has been proposed (see, for example, Patent Document 3).
JP 2003-133068 A JP 2003-313655 A JP 2003-321767 A

  However, even when the film thickness uniformity of the organic layer, which is the light emitting layer, can be secured by the methods proposed in Patent Document 2 and Patent Document 3, the light emission luminance of the obtained organic EL element is uniform. There was a case that it did not become a problem.

  This invention is made | formed in view of the above technical subjects, and the objective of this invention is providing the manufacturing method and manufacturing apparatus with which the organic electroluminescent element with uniform light-emitting luminance in an element is obtained. .

  In order to solve the above problems, the present invention has the following features.

  1. A vapor deposition step of forming a plurality of layers including one or more organic layers as a light emitting layer and a second electrode on a surface of the substrate provided with the first electrode by a vapor deposition method; In the method of manufacturing an organic electroluminescent element, prior to the vapor deposition step, the surface of the substrate on which the first electrode is provided includes one or more organic layers as the light emitting layer and a second electrode by vapor deposition. Based on a test vapor deposition step of forming a plurality of layers, a luminance distribution measurement step of measuring an emission luminance distribution by emitting light from the element formed by the test vapor deposition step, and a measurement result in the luminance distribution measurement step, A substrate position adjusting step for adjusting a relative position of the substrate for manufacturing the organic electroluminescent element with respect to a vapor deposition source for vapor-depositing one or more organic layers as a light emitting layer; Method of manufacturing an organic electroluminescent device characterized.

  2. 2. The organic electroluminescence device according to 1, wherein the substrate for manufacturing the organic electroluminescence device is a flexible substrate, and the substrate position adjusting step includes a step of bending and holding the flexible substrate. Manufacturing method.

  3. A step of feeding out the flexible strip-shaped substrate wound up in a roll, and a surface of the fed-out strip substrate on which the first electrode is provided, the organic layer having one or more light-emitting layers and the second electrode And a step of forming a plurality of layers by a vapor deposition method, wherein a plurality of layers including one or more organic layers that are the light-emitting layers and a second electrode in the belt-like substrate are formed. A luminance distribution measuring step of measuring emission luminance distribution by causing at least a portion of the emitted light to emit light, and depositing one or more organic layers as the light emitting layer based on a measurement result in the luminance distribution measuring step The manufacturing method of the organic electroluminescent element characterized by having the board | substrate position adjustment process which adjusts the relative position of a vapor deposition source and the said strip | belt-shaped board | substrate.

  4). Means for feeding out a flexible strip-shaped substrate wound up in a roll, and one or more organic layers as light-emitting layers and a second electrode on the surface of the fed-out strip-shaped substrate provided with the first electrode In an apparatus for manufacturing an organic electroluminescence device having a means for forming a plurality of layers by vapor deposition, a plurality of layers including one or more organic layers that are the light emitting layers in the strip substrate and a second electrode are formed. A luminance distribution measuring means for measuring at least a part of the emitted light and measuring a light emission luminance distribution, and at least one organic layer as the light emitting layer is deposited based on a measurement result by the luminance distribution measuring means. An apparatus for manufacturing an organic electroluminescence element, comprising substrate position adjusting means for adjusting a relative position between an evaporation source for forming the film and the belt-like substrate.

  According to the present invention, based on the measurement result of the emission luminance distribution in the substrate of the element manufactured earlier, the film thickness distribution of the electrode is adjusted by adjusting the film thickness of the organic layer that is the light emitting layer of the element manufactured later. Provided are an organic EL element manufacturing method and a manufacturing apparatus capable of obtaining an organic EL element having uniform light emission luminance in an element by correcting a light emission luminance distribution due to a shape or the like with a film thickness of an organic layer which is a light emitting layer. be able to.

  Hereinafter, embodiments of the present invention will be described in detail.

  As described above, conventionally, even if the thickness of the organic layer as the light emitting layer is uniform, the light emission luminance of the obtained organic EL element may not be uniform, which has been a problem. As a result of the present inventors diligently examining the cause, the light emission luminance of the organic EL element is not only the thickness of the organic layer as the light emitting layer, but also the shape of the electrode pattern, the film thickness of the electrode, and the relationship between the organic layer and the electrode. It has been estimated that it is influenced by the state of the interface. Further, prior to the manufacture of the organic EL element, the emission luminance distribution in the substrate of the element manufactured by the test vapor deposition is measured, and based on the result, the position of the substrate at the time of vapor deposition is adjusted to adjust the organic layer as the light emitting layer. It has been found that by adjusting the film thickness, the light emission luminance distribution due to the shape of the electrode pattern and the like is corrected by the film thickness of the organic layer, and an organic EL device having uniform light emission luminance in the device can be obtained.

  In general, the light emission luminance of an organic EL element varies depending on the film thickness of an organic layer that is a light emitting layer. On the other hand, the film thickness of the organic layer varies depending on the distance between the vapor deposition source and the substrate. Therefore, prior to the manufacture of the organic EL element, the emission luminance can be made uniform by adjusting the position of the substrate with respect to the vapor deposition source based on the measured value of the emission luminance distribution of the element manufactured by the test vapor deposition. In other words, the emission luminance distribution generated by the shape of the electrode pattern, the film thickness of the electrode, the state of the interface between the organic layer and the electrode, etc. is canceled by providing the distribution in the film thickness of the organic layer as the light emitting layer. Thus, an organic EL element having uniform emission luminance can be obtained.

The organic EL device produced by the method of the present invention may be a single color light emitting device comprising a single light emitting layer or a white light emitting device having a plurality of light emitting layers. In any case, it is possible to make the light emission luminance uniform by adjusting the position of the substrate with respect to the vapor deposition source based on the measured value of the light emission luminance distribution. Furthermore, the organic EL element having a plurality of light emitting layers In this case, the distribution of light emission luminance differs for each light emission color and may appear as color unevenness. Also in this case, the color unevenness can be eliminated by adjusting the thickness of the corresponding light emitting layer based on the measured value of the light emission luminance distribution for each color and canceling it.

  Hereinafter, the structure of the organic EL element manufactured by the method of the present invention will be described in detail.

  Although the typical example of a structure of the organic EL element manufactured by the method of this invention is shown below, it is not limited to these.

(I) Substrate / anode / light emitting layer / electron transport layer / cathode (ii) Substrate / anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) Substrate / anode / hole transport layer / light emitting layer / Hole blocking layer / electron transport layer / cathode (iv) Substrate / anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode (v) Substrate / anode / hole injection layer / Hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode Here, the light emitting layer includes at least one organic layer, and may include a plurality of organic layers. In the case where the light emitting layer includes a plurality of organic layers, it may have a non-light emitting intermediate layer.

  There is no particular limitation on the material of the substrate, which may be transparent or opaque. However, when light is extracted from the substrate side, the substrate is preferably transparent. As the transparent substrate, glass, quartz, transparent resin film or the like can be used. As the opaque substrate, metals such as aluminum or stainless steel, opaque resin films, various ceramics, or the like can be used. Among them, the resin film is particularly suitable for the method of the present invention because it is flexible.

  Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate (CAP), Cellulose esters such as cellulose acetate phthalate (TAC) and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones, Cycloforms such as polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR Corporation) or Appel (trade name, manufactured by Mitsui Chemicals, Inc.) Examples include olefin resins.

Moreover, you may use the barrier film in which the barrier film which consists of a film | membrane which consists of the film | membrane which consists of a film | membrane which consists of an inorganic material or an organic material, or both of them on the surface of a resin film is used. In this case, it is preferably a barrier film having a water vapor permeability measured by a method according to JIS K 7129-1992 of 0.01 g / m ² · day · atm or less, and further, a water vapor permeability of 10 ^{− 5} g / m ² · day · atm or less, and the oxygen permeability measured by a method based on JIS K 7126-1992 is 10 ^-3 g / m ² · day · atm or less high barrier film. Is preferred.

  As a material for forming the 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. Furthermore, in order to improve the brittleness of the barrier film, it is more preferable to have a laminated structure of these inorganic layers and layers made of organic materials. Although there is no restriction | limiting in particular about the lamination order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

  There is no particular limitation on the method for forming the barrier film. For example, vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, 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. Among them, the method using an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

The anode material can be appropriately selected from metals, alloys, electrically conductive compounds, mixtures thereof, and the like, but a material having a high work function (4 eV or more) is preferable. Examples thereof 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 IZO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used.

  The anode can be produced by forming a thin film of these anode materials on a substrate by a method such as vapor deposition or sputtering, and then forming an anode pattern having a desired shape by a photolithography method. Further, when forming a thin film of an anode material on a substrate by a method such as vapor deposition or sputtering, it can be produced by forming an anode pattern by forming a film through a mask having a desired shape. Furthermore, when a material that can be applied, such as an organic conductive compound, is used as the anode material, it can also be produced by a wet film forming method such as a printing method or a coating method.

  When light is extracted from the substrate side through the anode, it is desirable that the transmittance of the anode be greater than 10%, and the sheet resistance of the anode is preferably several hundred Ω / □ or less. Although the film thickness of an anode is based also on material, it can select suitably in 10-1000 nm normally, Preferably it is the range of 10-200 nm.

On the other hand, the cathode material can be appropriately selected from metals, alloys, electrically conductive compounds, and mixtures thereof, but a material having a small work function (less than 4 eV) is preferable. For example, aluminum, sodium, sodium-potassium alloy, magnesium, lithium, indium, rare earth metal, etc. are mentioned. Furthermore, from the viewpoint of durability against electron injection and oxidation, it is more preferable to use a mixture of a metal having a low work function and a second metal, which is a stable metal having a larger work function value than that, as the electrode material. . Examples thereof include a magnesium / copper mixture, a magnesium / silver mixture, a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, and a lithium / aluminum mixture.

  The cathode can be produced by forming a thin film of these cathode materials by vapor deposition. The sheet resistance of the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 to 5000 nm, preferably 50 to 200 nm.

  The light emitting layer is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport 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.

  The light emitting layer preferably contains a host compound and a phosphorescent compound which is a light emitting dopant. As the host compound and the phosphorescent compound, known compounds generally used in organic EL elements can be used. Further, a plurality of known host compounds and phosphorescent 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 superimpose light having different wavelengths, 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.

  Specific examples of known host compounds include compounds described in the following documents.

  JP 2001-257076 A, JP 2002-308855 A, JP 2001-313179 A, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445 gazette, 2002-343568 gazette, 2002-141173 gazette, 2002-352957 gazette, 2002-203683 gazette, 2002-363227 gazette, 2002-231453 gazette, No. 003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060, No. 2002. -302516, 2002-305083, 2002-305084, 2002-308837, and the like.

  As the phosphorescent compound, known compounds generally used in organic EL devices can be used as described above. For example, an iridium compound, an osmium compound, a platinum compound (platinum complex compound), a rare earth complex, or the like can be used. Specific examples of the phosphorescent compound include compounds described in the following documents.

  International Publication No. 00/70655 pamphlet, JP 2002-280178 A, 2001-181616, 2002-280179, 2001-181617, 2002-280180, 2001-247859. Gazette, 2002-299060, 2001-313178, 2002-302671, 2001-345183, 2002-324679, WO 02/15645, JP 2002 No. 332291, No. 2002-50484, No. 2002-332292, No. 2002-83684, No. 2002-540572, No. 2002-117978, No. 2002-338588, 002-170684, 2002-352960, WO 01/93642, JP 2002-50483, 2002-1000047, 2002-173684, 2002-35982 No. 2002-175844, No. 2002-363552, No. 2002-184582, No. 2003-7469, No. 2002-525808, No. 2003-7471, No. 2002-525833. Publication No. 2003-31366 Publication No. 2002-226495 Publication No. 2002-234894 Publication No. 2002-2335076 Publication No. 2002-241751 Publication No. 2001-319779 Publication No. 2001-3197 0, JP same 2002-62824, JP same 2002-100474, JP same 2002-203679, JP same 2002-343572, JP same 2002-203678 Patent Publication.

The hole transport layer is a layer made of a material having a function of transporting holes. The material used for the hole transport layer may be any material that has either hole injection or transport or 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, conductive polymer oligomers, thiophene oligomers, etc. The hole transport layer can be produced by depositing the above materials by vapor deposition. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, about 5-5000 nm, Preferably it is 5-200 nm. The hole transport layer may have a multilayer structure composed of two or more of the above materials.

  The electron transport layer is a layer made of a material having a function of transporting electrons. The material used for the electron transport layer only needs to have a function of transmitting electrons injected from the cathode to the light emitting layer, and any one of known compounds can be selected and used. Examples include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, and the like. Moreover, in the said oxadiazole derivative, the thiadiazole derivative which substituted the oxygen atom of the oxadiazole ring by the sulfur atom, and the quinoxaline derivative which has a quinoxaline ring known as an electron withdrawing group can also be used. 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.

  The electron transport layer can be produced by depositing the above material by vapor deposition. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, about 5-5000 nm, Preferably it is 5-200 nm. The electron transport layer may have a multilayer structure composed of two or more of the above materials.

  The hole blocking layer has a function of an electron transport layer in a broad sense. It is made of a material that has a function of transporting electrons and has an extremely small ability to transport holes, and is provided for the purpose of improving the recombination probability of electrons and holes. The material of the hole blocking layer can be appropriately selected from the materials used for the above-described electron transport layer as necessary. For example, Japanese Patent Application Laid-Open Nos. 11-204258 and 11-204359, “Organic EL elements and the forefront of industrialization”, NTS, Nov. 30, 1998, p. The hole blocking layer described in 237 can be used.

  The injection layer is a layer provided for lowering the voltage required for driving and improving light emission luminance, and is divided into a hole injection layer and an electron injection layer. The injection layer is preferably a very thin film, and the film thickness is preferably in the range of 0.1 to 5000 nm, although it depends on the material. In addition, regarding the injection layer, “Organic EL element and its industrialization front line”, NTS, November 30, 1998, p. 123-166.

  The details of the hole injection layer are described, for example, in JP-A-9-45479, JP-A-9-260062, and JP-A-8-288069. Specific examples include phthalocyanine represented by copper phthalocyanine. Examples include a buffer layer, an oxide buffer layer typified by vanadium oxide, an amorphous carbon buffer layer, a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene, and the like.

  The details of the electron injection layer are described in, for example, JP-A-6-325871, JP-A-9-17574, and JP-A-10-74586, and specifically represented by strontium, aluminum, and the like. Examples thereof include a metal buffer layer, an alkali metal compound buffer layer typified by lithium fluoride, an alkaline earth metal compound buffer layer typified by magnesium fluoride, and an oxide buffer layer typified by aluminum oxide.

  The outline of the process of the manufacturing method which is one embodiment of this invention is shown in FIG. This process is a process of a manufacturing method based on a method of processing relatively small substrates one by one (hereinafter referred to as “single wafer method”). Hereinafter, each step will be described in order.

  The substrate setting step S101 is a step of carrying a substrate on which the first electrode is provided in advance into the vapor deposition chamber and holding the substrate at a predetermined position in the vapor deposition chamber. After the substrate is carried in, the inside of the vapor deposition chamber is depressurized by a vacuum pump and adjusted to a predetermined degree of vacuum.

  The test vapor deposition step S102 is a step of forming a plurality of layers including at least one organic layer and a second electrode on the surface of the set substrate on which the first electrode is provided by a vapor deposition method. A hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, a cathode, and the like are sequentially formed in accordance with the configuration of the organic EL element to be manufactured. Formation of these layers by a vapor deposition method can be appropriately selected according to the material from generally widely used methods such as a resistance heating method, an electron beam heating method, and an indirect heating method. Further, all the layers to be formed may be formed in one vapor deposition chamber, or may be divided into a plurality of vapor deposition chambers.

  The luminance distribution measurement step S103 is a step of measuring the emission luminance distribution by causing the organic EL element formed in the test vapor deposition step S102 to emit light. There is no particular limitation on the measurement method. For example, the organic EL element formed in the test vapor deposition step S102 can be transferred to a luminance distribution measurement chamber, the organic EL element can emit light in the luminance distribution measurement chamber, and the luminance can be measured using a luminance meter. A luminance meter that is generally widely used can be used as appropriate. In order to prevent the deterioration of the organic EL element, the luminance distribution measurement chamber is preferably an inert gas atmosphere. As the inert gas, argon or nitrogen is particularly preferable.

  In the luminance distribution measuring step S103, the power source for causing the organic EL element to emit light is preferably a constant voltage power source. The organic EL element is a current-driven element. However, as described later, the luminance distribution is caused by a difference in electric field strength applied to the organic layer. Therefore, the luminance distribution can be measured more accurately by making the electric field strength applied to the organic layer of each element constant. In addition, in order to more accurately correct the light emission luminance distribution due to the film thickness distribution and shape of the electrodes, the light emission luminance distribution is measured by emitting light with a luminance close to that when the organic EL element to be manufactured is actually used. It is preferable to do.

  In order to obtain the luminance distribution, it is preferable to measure the emission luminance at two or more locations per substrate. In order to measure the emission luminance at a plurality of locations on one substrate, the position of the luminance meter may be fixed and the organic EL element may be moved, or the position of the organic EL element may be fixed and the luminance meter moved. May be. Moreover, you may move and measure both a luminance meter and an organic EL element.

  The substrate position adjustment amount determination step S104 is a step of determining the substrate position adjustment amount necessary for correcting the light emission luminance distribution based on the measurement result of the light emission luminance distribution of the organic EL element in the luminance distribution measurement step S103. .

  The relationship between the film thickness of the light emitting layer and the light emission luminance (hereinafter referred to as “the relationship between the film thickness and the luminance”) and the relationship between the distance from the vapor deposition source to the substrate and the film thickness of the light emitting layer (hereinafter, “ The relationship between the distance and the film thickness "is investigated, and the relationship between the distance from the evaporation source to the substrate and the light emission luminance (hereinafter referred to as" the relationship between the distance and the luminance ") is obtained from these two relationships. Keep it.

  First, the relationship between film thickness and luminance will be described. Under a certain voltage, the intensity of the electric field applied to the light emitting layer changes depending on the film thickness of the light emitting layer, and the light emission luminance changes when the intensity of the electric field changes. Although the film thickness and the electric field strength are in an inversely proportional relationship, the relationship between the electric field strength and the light emission luminance differs depending on the configuration and material of the organic EL element. Therefore, the relationship between the film thickness and the luminance is obtained for each configuration and material of the organic EL element to be manufactured. It is preferable that a plurality of organic EL elements in which the film thickness of the light emitting layer is actually changed are manufactured and the relationship between the film thickness and luminance is obtained by measuring the luminance. An example of a general relationship between film thickness and luminance under a certain voltage is shown in FIG.

  Next, the relationship between distance and film thickness will be described. In the vapor deposition method, it is known that the film thickness is inversely proportional to the square of the distance between the vapor deposition source and the substrate. An example of the relationship between the distance and the film thickness is shown in FIG.

  From the relationship between the film thickness and the luminance and the relationship between the distance and the film thickness obtained in this way, the relationship between the distance and the luminance can be obtained. An example of the relationship between distance and luminance is shown in FIG. By applying the result of the luminance distribution measurement in the luminance distribution measuring step S103 to the relationship between the distance and the luminance obtained here, the adjustment amount of the substrate position necessary for correcting the light emission luminance distribution can be determined. .

  In the substrate position adjustment step S105, a substrate for manufacturing an organic EL element provided with the first electrode in advance is carried into the vapor deposition chamber, and the substrate is held at the position determined in the substrate position adjustment amount determination step S104. It is. The substrate position can be adjusted, for example, by tilting and holding the substrate with respect to the vapor deposition source. Further, when a flexible substrate such as a resin film is used, the position can be adjusted not only by tilting the substrate but also by bending the substrate, so that the light emission luminance distribution can be corrected with higher accuracy.

  The vapor deposition step S106 is a step of forming a plurality of layers including at least one organic layer and the second electrode by a vapor deposition method on the surface of the substrate for manufacturing the organic EL element provided with the first electrode. is there. It can be performed by the same method as the test vapor deposition step S102.

  When all the layers constituting the organic EL element are formed in the vapor deposition step S106, the organic EL element is completed. Depending on the configuration of the organic EL element to be manufactured, a sealing step for preventing the deterioration of the organic EL element can be further performed. In addition, by using the obtained organic EL element, the luminance distribution distribution can be corrected with higher accuracy by repeating the luminance distribution measurement step S103 to the vapor deposition step S106 again. The luminance distribution measuring step S103 to the vapor deposition step S106 may be repeated every time an organic EL element is obtained in the vapor deposition step S106.

  Next, a manufacturing method called a roll-to-roll method which is another embodiment of the present invention will be described. An outline of the roll-to-roll process is shown in FIG.

  The roll-to-roll method is a method in which an organic EL element is formed by evaporation while a flexible belt-like substrate such as a resin film previously wound in a roll shape is unwound from a roll and continuously or intermittently conveyed. After forming the organic EL element, it may be wound up again in a roll shape, or may be cut and stocked. In this roll-to-roll method, the tendency of the light emission luminance distribution of the organic EL element often changes constantly or continuously within the roll, so that a particularly high effect can be obtained by the method of the present invention.

  In this roll-to-roll system, the process performed between the time when the substrate is unwound and the time when it is wound up again or until it is cut and stocked is called an in-line process, and the organic EL element is formed on the substrate. A process performed after the substrate is wound again or after the substrate is cut and stocked is referred to as an off-line process.

  Substrate unwinding step S201 is a step of unrolling a belt-shaped substrate wound in advance in a roll shape and transporting it to a region where vapor deposition steps S202 and S206 are performed.

  A substrate in which the first electrode is provided in advance may be used in a roll shape, or the first electrode may be formed in-line using a substrate on which the first electrode is not provided. From the viewpoint of preventing a short circuit between the electrodes of the organic EL element due to scattering of metal powder during electrode formation, it is preferable to use a substrate on which a first electrode is provided in advance.

  Further, a substrate cleaning step may be provided in-line before the vapor deposition step S202. The cleaning method is not particularly limited, and can be appropriately selected from dry cleaning such as plasma cleaning, wet cleaning such as drying after being immersed in an ultrasonic cleaning tank, or a combination of these dry cleaning and wet cleaning.

  The vapor deposition step S202 is a step of forming a plurality of layers including at least one organic layer and the second electrode on the surface of the transported belt-like substrate on which the first electrode is provided by a vapor deposition method. It can be performed by the same method as the single wafer deposition process S107. FIG. 6 shows a schematic diagram of the positional relationship between the vapor deposition source and the substrate. In order to make the film thickness in the width direction of the belt-like substrate 1 uniform, it is preferable to use a linear evaporation source in which the evaporation material is distributed linearly as the evaporation source 2.

  In the luminance distribution measurement step S203, at least a part of the portion where the plurality of layers including the one or more organic layers and the second electrode, which are light emitting layers in the vapor deposition step S202, are formed in the belt-like substrate is caused to emit light. This is a step of measuring the distribution. It can be performed by the same method as in the single wafer luminance distribution measurement step S103.

  The substrate position adjustment amount determination step S204 is a step of determining the substrate position adjustment amount necessary for correcting the light emission luminance distribution based on the measurement result of the light emission luminance distribution in the luminance distribution measurement step S203. It can be performed by the same method as the single-wafer type substrate position adjustment amount determination step S104.

  The substrate position adjustment step S205 is a step of adjusting the substrate position of the band-shaped substrate in the region where the vapor deposition step S202 is performed based on the adjustment amount determined in the substrate position adjustment amount determination step S204. FIG. 7 shows a schematic diagram of the substrate position adjusting method. FIG. 7 is a view of the belt-like substrate 1 and the vapor deposition source 2 as viewed from the longitudinal direction (transport direction) of the belt-like substrate 1, and the area where the material evaporated by the vapor deposition source 2 rises toward the belt-like substrate 1 is shaded. Is shown. FIG. 7A shows a state before adjustment, a state in which the belt-like substrate 1 is held horizontally with respect to the vapor deposition source 2, FIG. 7B shows a state in which the belt-like substrate 1 is tilted and adjusted with respect to the vapor deposition source 2, and FIG. The state which bent and adjusted the strip | belt-shaped board | substrate 1 is each shown. FIG. 8 shows a schematic view of an example of a holding means for bending and adjusting the substrate. While pulling the strip-shaped substrate 1 in the width direction by the substrate pulling jig 4, the position of the strip-shaped substrate 1 is adjusted by bending the guide 3 provided outside the deposition range 5.

  When the substrate position of the belt-like substrate is adjusted by the substrate position adjusting step S205, the organic EL element is formed by the vapor deposition step S206. The portion of the belt-like substrate where the formation of the organic EL element in the vapor deposition step S206 is completed is sequentially sent to the substrate winding step S207 and wound up again in a roll shape.

  The steps from the luminance distribution measurement step S203 to the substrate position adjustment step S205 need to be performed at least once for one roll-shaped substrate, and are preferably performed near the top of the substrate fed out from the roll. Further, it may be repeated every predetermined interval of the substrate or every predetermined time.

  Moreover, you may perform another other process in-line after a vapor deposition process. For example, a barrier film for preventing deterioration of the organic EL element, a protective film, or the like can be applied. In addition, other processes may be performed in-line or offline as long as the object of the present invention is not hindered.

Example 1
Using a glass substrate, an organic EL element was produced by a single wafer method. FIG. 9 shows the configuration of the produced organic EL element. On the surface of the substrate 11, an anode 12 made of ITO, a hole transport layer 13 made of α-NPD (4,4′-bis [N- (naphthyl) -N-phenyl] -amino-biphenyl), CBP (4, A light-emitting layer 14 made of a mixture of 4′-Dicarbazol-1,1′diphenyl) and IR-1, and a hole blocking layer 15 made of BCP (2,9-dimethy-4,7-diphenyl-1,10-phenthroline). , An electron transport layer 16 made of Alq ₃ (Tris- (8-hydroxyquinoline) aluminum), an electron injection layer 17 made of lithium fluoride, and a cathode 18 made of aluminum are sequentially laminated.

  A schematic view of the apparatus used in this example is shown in FIG. A substrate storage chamber 101, a first vapor deposition chamber 102, a second vapor deposition chamber 103, and a delivery chamber 104 are connected around the substrate transport chamber 100 via vacuum valves 111, 112, 113, and 114, respectively. The delivery chamber 104 is connected to the luminance distribution measurement chamber 105 via a further vacuum valve 115. The substrate transport chamber 100 is provided with a substrate moving device 106 for moving the substrate stored in the substrate storage chamber 101 to each of the first vapor deposition chamber 102, the second vapor deposition chamber 103, and the delivery chamber 104. Yes. Each of the substrate transport chamber 100, the substrate storage chamber 101, the first vapor deposition chamber 102, the second vapor deposition chamber 103, and the delivery chamber 104 is provided with a vacuum pump (not shown), and the inside is kept in a predetermined vacuum state. I'm leaning.

  As the substrate, a glass substrate (NH Techno Glass, NA-45) on which an ITO thin film (thickness 150 nm) was previously formed was used. The size of the substrate was 75 mm × 75 mm. The ITO film was patterned into the shape shown in FIG. The substrate was ultrasonically cleaned with iso-propyl alcohol, dried with dry nitrogen gas, and then UV ozone cleaned. The cleaned substrate was stored in the substrate storage chamber 101.

Each of the first vapor deposition chamber 102 and the second vapor deposition chamber 103 is provided with a resistance heating type vapor deposition source. The deposition source of the first deposition chamber 102 includes α-NPD that is a material of the hole transport layer 13, CBP that is a host compound of the light emitting layer 14, Ir-1 that is a light emitting dopant of the light emitting layer 14, and a hole blocking layer. BCP, which is a material of 15, and Alq ₃ which is a material of the electron transport layer 16, were each placed in a resistance heating boat made of tantalum. As the vapor deposition source of the second vapor deposition chamber 103, lithium fluoride, which is the material of the electron injection layer 17, was placed in a tantalum resistance heating boat, and aluminum, which was the material of the cathode 18, was placed in a tungsten resistance heating boat. I attached something.

  In the first vapor deposition chamber 102 and the second vapor deposition chamber 103, a stainless steel rectangular perforated mask for regulating the film formation region was attached. The mask was prepared so that the film formation size was 50 mm × 50 mm.

  The substrate stored in the substrate storage chamber 101 was transferred to the first vapor deposition chamber 102 by the substrate moving device 106. The distance from the central position of the two vapor deposition sources in the first vapor deposition chamber 102 to the measurement point E of the substrate shown in FIG. 12 is 500 mm, and 4 from the central position of the two vapor deposition sources to AD of the substrate shown in FIG. The substrate was fixed so that the distances to the two measurement points were equal.

  The first vapor deposition chamber 102 was sealed by closing the vacuum valve 112, and the pressure was reduced to 4 × 10 −4 Pa by a vacuum pump. Thereafter, the resistance heating boat containing α-NPD is energized and heated, and vapor deposition is performed at a deposition rate of 0.1 nm / second to 0.2 nm / second to a thickness of 25 nm. Formed.

  Next, the resistance heating boat containing CBP and the resistance heating boat containing Ir-1 are energized and heated so that the ratio between the CBP deposition rate and the Ir-1 deposition rate is 100: 7. Then, film formation was performed simultaneously to form a light emitting layer 14 having a thickness of 30 nm.

Subsequently, the resistance heating boat containing BCP was energized and heated to provide a hole blocking layer 15 having a thickness of 10 nm at a deposition rate of 0.1 nm / second to 0.2 nm / second. Further, a resistance heating boat containing Alq ₃ was heated by energization to provide an electron transport layer 16 having a film thickness of 40 nm at a deposition rate of 0.1 nm / second to 0.2 nm / second.

  A substrate in which the hole transport layer 13, the light emitting layer 14, the hole blocking layer 15, and the electron transport layer 16 were sequentially laminated on the anode 12 was transported to the second vapor deposition chamber 103 by the substrate moving device 106 and fixed. The first vapor deposition chamber 102, the substrate transport chamber 100, and the second vapor deposition chamber 103 were depressurized and transported while the substrate was not exposed to the atmosphere. An electric current is passed through a resistance heating boat containing lithium fluoride in a state where the pressure in the second vapor deposition chamber 103 is reduced to 2 × 10 −4 Pa, and an electron having a film thickness of 0.5 nm at a vapor deposition rate of 0.01 nm / second to 0.02 nm / second. An injection layer 17 was formed. Next, electricity was passed through a resistance heating boat containing aluminum, and a cathode 18 having a film thickness of 150 nm was formed at a deposition rate of 1 nm / second to 2 nm / second to obtain an organic EL element 10A.

  The obtained organic EL element 10A was transported to the luminance distribution measurement chamber 105 without being exposed to the atmosphere. The luminance distribution measurement chamber 105 is maintained in a nitrogen atmosphere having a residual oxygen concentration of 1 ppm or less. Here, a voltage of 6 V was applied to the organic EL element 10A to emit light, and the light emission luminance distribution was measured using a luminance meter (CS1000A) manufactured by Konica Minolta Sensing. There were five measurement points A to E shown in FIG.

  The relative luminance at each measurement point when the luminance at measurement point A is 100 is shown in Table 1 (Comparative Example 1). The luminance uniformity of the organic EL element 90 (a) was 60%.

Brightness uniformity [%] = (minimum luminance [cd / m ² ] / maximum luminance [cd / m ² ]) × 100

  The adjustment amount of the substrate position necessary for correcting the light emission luminance distribution was calculated from the result of the luminance distribution measurement shown in Table 1 and the relationship between the distance and the luminance obtained in advance shown in FIG. The distance from the central position of the two vapor deposition sources in the vapor deposition chamber 102 to the measurement point E is not changed, and the distance from the central position of the two vapor deposition sources to the measurement point C and the measurement point D is 2 mm away. It was found that the luminance distribution can be corrected by tilting the substrate so that the distance to the measurement point B approaches 2 mm.

  Therefore, a new substrate is transferred to the first vapor deposition chamber 102, the distance from the center position of the two vapor deposition sources in the first vapor deposition chamber 102 to the measurement point E is set to 500 mm, and the measurement point is measured from the central position of the two vapor deposition sources. The substrate was tilted and fixed so that the distance to C and measurement point D was 2 mm away, and the distance to measurement point A and measurement point B was closer to 2 mm. After forming the light emitting layer 13 in this state, it was conveyed to the 2nd vapor deposition chamber 103, the electron injection layer 14 and the cathode 15 were formed, and the organic EL element 10B was obtained.

  The results of measuring the luminance distribution of the obtained organic EL element 10B are shown in Table 2 (Example 1). The luminance uniformity was improved to 80%, and an organic EL device having practically sufficient performance could be obtained.

(Example 2)
An organic EL element 10C was produced with the same configuration and conditions as in Example 1 except that a 100 μm thick polyethylene naphthalate film (a film made by Teijin and Deyupon) (hereinafter referred to as “PEN film”) was used as the substrate. . The obtained organic EL element 10C was conveyed to the luminance distribution measurement chamber 105, and the emission luminance distribution was measured. Table 3 shows the relative luminance at each measurement point when the luminance at the measurement point A is 100 (Comparative Example 2). The luminance uniformity of the organic EL element 10C was 61%.

  The adjustment amount of the substrate position necessary for correcting the light emission luminance distribution was calculated from the result of the luminance distribution measurement shown in Table 3 and the relationship between the distance and the luminance obtained in advance shown in FIG. The substrate is tilted while being bent so that the deposition source side has a concave shape, and the distance from the center position of the two deposition sources in the first deposition chamber 102 to the measurement point E is not changed, but to the measurement point A and the measurement point B. It has been found that the luminance distribution can be corrected by bringing the distance of 8mm closer to 8 mm and the distance to the measurement point C and the measurement point D closer to 4 mm.

  Therefore, a new substrate is transported to the first vapor deposition chamber 102 and tilted while bending the substrate so that the vapor deposition source side has a concave shape, and from the center position of the two vapor deposition sources in the first vapor deposition chamber 102 to each measurement point. The distance was fixed at the position adjusted as described above. After forming the light emitting layer 13 in this state, it was conveyed to the 2nd vapor deposition chamber 103, the electron injection layer 14 and the cathode 15 were formed, and organic EL element 10D was obtained.

  The result of measuring the luminance distribution of the obtained organic EL element 10D is shown in Table 4 (Example 2). The luminance uniformity was improved to 92%, and an organic EL device having practically sufficient performance could be obtained. Since the position is adjusted not only by tilting but also by bending the substrate, even higher effects can be obtained than in Example 1.

(Example 3)
A schematic diagram of the roll-to-roll manufacturing apparatus used in this example is shown in FIG. An ITO film as the anode 12 having a shape shown in FIG. 15 was formed on the surface of a PEN film having a width of 240 mm, a length of 20 m, and a thickness of 100 μm, and then wound into a roll to form a substrate 200. The configuration of the organic EL element to be manufactured is the same as that of Example 1.

14 includes a substrate feeding device 201, an ultrasonic cleaning device 202 using iso-propyl alcohol, a drying device 203 using dry nitrogen gas, gate valves 204 and 205, a vapor deposition device 206, a luminance distribution measuring device 207, and a substrate winding device. A take-off device 208 is provided. Further, α-NPD, CBP, Ir-1, BCP, Alq ₃ , lithium fluoride, and aluminum were respectively attached to the evaporation source of the evaporation apparatus 206 in a resistance heating boat.

The substrate 200 fed out by the substrate feed-out 201 is cleaned and dried by the ultrasonic cleaning device 202 and the drying device 203 and then transferred to the vapor deposition device 206 through the gate valve 204. With respect to the substrate transported to the vapor deposition apparatus 206, the hole transport layer 13 (α-NPD), the light emitting layer 14 (CBP + Ir-1), the hole blocking layer 15 (BCP), and the electrons under the same conditions as in Example 1. A transport layer 16 (Alq ₃ ), an electron injection layer 17 (lithium fluoride), and a cathode 18 (aluminum) were sequentially formed to obtain an organic EL device 20.

  The substrate after film formation was transferred to the luminance distribution measuring apparatus 207, and the luminance distribution was measured for the three elements in the fifth row and the three elements in the tenth row. The three elements in the fifth row are viewed from the substrate feed-out side, and the organic EL elements 20A, 20B, and 20C are arranged in order from the right. 20F.

  In the same manner as in Example 1, the light emission luminance was measured at five locations for each element, and the luminance uniformity was calculated. Moreover, the relative value (element relative luminance) of the five-point average luminance of each element based on the five-point average luminance of the organic EL element 20A was obtained as follows. The results are shown in Table 5 (Comparative Example 3).

Element relative luminance [%] = (5 element average luminance [cd / m ² ] / element 20A average luminance [cd / m ² ]) × 100

  Based on this measurement result, the position of the substrate in the vapor deposition apparatus 205 was adjusted by tilting while bending the substrate. The luminance distribution was measured for the three elements in the fifth column and the tenth column formed after adjusting the substrate position. The three elements in the fifth row are viewed from the substrate feed-out side, and the organic EL elements 21A, 21B, and 21C are arranged in order from the right side. 21F. Table 6 shows the luminance uniformity and element relative luminance of each element (Example 3). An organic EL element having good luminance uniformity and element relative luminance could be obtained.

Schematic of the process of the manufacturing method which is one embodiment of this invention. Schematic diagram of the relationship between film thickness and brightness Schematic diagram of the relationship between distance and film thickness Schematic diagram of the relationship between distance and brightness Schematic of the process of the manufacturing method which is another embodiment of this invention. Schematic diagram of positional relationship between deposition source and substrate Schematic diagram of substrate position adjustment method Schematic diagram of an example of holding means for bending and adjusting the substrate Configuration diagram of organic EL device fabricated in Example Schematic diagram of the apparatus used in Examples 1 and 2 The figure which shows the pattern shape of the ITO film | membrane of Examples 1 and 2 Diagram showing measurement points of emission luminance The figure which shows the relationship between the distance of the organic electroluminescent element produced in the Example, and a brightness | luminance Schematic diagram of the apparatus used in Example 3 The figure which shows the patterning shape of the ITO film | membrane of Example 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Strip | belt-shaped board | substrate 2 Evaporation source 3 Guide 4 Substrate tension jig | tool 5 Deposition range 11 Substrate 12 Anode 13 Hole transport layer 14 Light emitting layer 15 Hole blocking layer 16 Electron transport layer 17 Electron injection layer 18 Cathode 100 Substrate transport chamber 101 Substrate accommodation Chamber 102 First vapor deposition chamber 103 Second vapor deposition chamber 104 Delivery chamber 105 Brightness distribution measurement chamber 106 Substrate moving device 200 Roll substrate 201 Substrate feeding device 202 Ultrasonic cleaning device 203 Drying device 206 Vapor deposition device 207 Brightness distribution measurement device 208 Substrate winding Removing device

Claims (4)

A vapor deposition step of forming a plurality of layers including one or more organic layers as a light emitting layer and a second electrode on a surface of the substrate provided with the first electrode by a vapor deposition method; In the method of manufacturing an organic electroluminescence element,
Prior to the vapor deposition step,
A test vapor deposition step of forming a plurality of layers including one or more organic layers as the light emitting layer and a second electrode on the surface of the substrate on which the first electrode is provided;
Luminance distribution measurement step of measuring the emission luminance distribution by emitting light from the element formed by the test vapor deposition step,
A substrate position for adjusting a relative position of the substrate for manufacturing the organic electroluminescence element with respect to a vapor deposition source for vapor-depositing one or more organic layers as the light emitting layer based on a measurement result in the luminance distribution measurement step The manufacturing method of the organic electroluminescent element characterized by having an adjustment process. 2. The organic electroluminescence device according to claim 1, wherein the substrate for manufacturing the organic electroluminescence element is a flexible substrate, and the substrate position adjusting step includes a step of bending and holding the flexible substrate. Manufacturing method of luminescence element. A step of feeding out the flexible strip-shaped substrate wound up in a roll, and a surface of the fed-out strip substrate on which the first electrode is provided, the organic layer having one or more light-emitting layers and the second electrode In the method of manufacturing an organic electroluminescence device having a step of forming a plurality of layers by vapor deposition,
A luminance distribution measuring step of measuring a light emission luminance distribution by emitting at least a part of a portion where a plurality of layers including one or more organic layers as the light emitting layer and a second electrode are formed on the belt-shaped substrate; ,
And a substrate position adjusting step of adjusting a relative position between a deposition source for depositing one or more organic layers as the light emitting layer and the strip substrate based on a measurement result in the luminance distribution measuring step. A method for manufacturing an organic electroluminescence element. Means for feeding out a flexible strip-shaped substrate wound up in a roll, and one or more organic layers as light-emitting layers and a second electrode on the surface of the fed-out strip-shaped substrate provided with the first electrode In an apparatus for manufacturing an organic electroluminescence element having a means for forming a plurality of layers by vapor deposition,
Luminance distribution measuring means for measuring emission luminance distribution by emitting at least part of a portion of the belt-shaped substrate where a plurality of layers including one or more organic layers as the light emitting layer and a second electrode are formed. When,
And a substrate position adjusting means for adjusting a relative position between the deposition source for depositing one or more organic layers as the light emitting layer and the belt-like substrate based on a measurement result by the luminance distribution measuring means. An apparatus for manufacturing an organic electroluminescence element.

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