JP2012216534A - Organic el element manufacturing method and organic el element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an organic EL element in which an organic light-emitting layer is formed by a printing method and an organic EL element, which cause less occurrence of film defect such as a difference in film thickness between pixels and awkward film shape, and no emission unevenness.SOLUTION: In a manufacturing method of an organic EL element, in which pixel electrodes on a substrate, barriers for defining the neighboring pixel electrodes from one another as a pixel that is a subpixel, and at least one layer of an organic EL layer composed of an organic compound for the pixel are formed by a letterpress printing method, a letterpress pattern for printing used in patterning is a striped pattern or a dot pattern and an acute angle θ among angles between a direction of a long side of the pattern and a printing direction is 45° or more and 90° or less.

Description

  The present invention relates to a method for manufacturing an organic EL element in which an organic electroluminescence (hereinafter abbreviated as EL) material film is formed by a relief printing method, and an organic EL element manufactured thereby, and is particularly used for manufacturing an organic EL element. It relates to a letterpress for printing.

  An organic EL element is a light emitting element having a structure in which an organic light emitting layer having an organic EL material is formed between two opposing electrodes, and emits light when a voltage is applied. In order to obtain efficient light emission, the film thickness of the organic light emitting layer is an important factor, and it is necessary to control the film thickness from several nm to several tens of nm.

  The organic EL material used for the organic light emitting layer is classified into a low molecular material and a high molecular material, and the formation method of the organic light emitting layer differs depending on the type of the material.

  Generally, a low molecular weight material is formed into a thin film on a substrate by resistance heating vapor deposition (vacuum vapor deposition) or the like. Although this method is an excellent method for forming a uniform thin film, there is a problem that it becomes difficult to maintain pattern accuracy when the substrate becomes large.

  On the other hand, in a polymer material, an organic light emitting material is dissolved or dispersed in a solvent to form an ink, and a thin film is formed by a wet coating method. As the wet coating method, there are a spin coating method, a bar coating method, a protruding coating method, a dip coating method, etc., but it is difficult to use for patterning and color coating, and in order to perform high-definition patterning, etc. It is necessary to use pattern printing by an ink jet method or a printing method.

  For example, Patent Document 1 discloses a pattern forming method using an ink jet method. In this method, a pattern is formed by ejecting an organic light emitting material dissolved in a solvent from an ink jet nozzle onto a substrate and drying it on the substrate. However, since the ink droplets ejected from the nozzle are spherical, the ink spreads in a circular shape when landing on the substrate, and the shape of the formed pattern lacks linearity or the landing accuracy is poor. Therefore, there is a problem that the linearity of the pattern cannot be obtained.

  In addition, there are various types of pattern forming methods by printing methods. For organic EL elements that often use glass substrates as substrates, offset printing methods using rubber printing blankets, rubber and other A letterpress printing method using a photosensitive resin plate mainly composed of a resin is considered an appropriate printing method. For example, Patent Document 2 discloses a pattern printing method using offset printing, and Patent Document 3 discloses a pattern printing method using relief printing. Among them, the method by letterpress printing is excellent in pattern formation accuracy and film thickness uniformity, and is most suitable as a method for producing an organic EL element by printing.

  As an example of the step of forming the organic light emitting layer of the organic EL element by the relief printing method, first, an organic EL material is dissolved or dispersed in a solvent to form an ink, which is applied to the roll surface of an anilox roll having fine holes. Next, excess ink on the surface of the anilox roll is scraped off with a doctor blade, so that the amount of ink applied per unit area of the anilox roll is made uniform. Then, the ink on the anilox roll is transferred to the image forming portion of the printing plate having the image forming portion provided corresponding to the shape of the pixel of the organic EL element, and finally the ink on the image forming portion of this printing plate. The organic light emitting layer of the organic EL element is formed on the substrate by transferring the thin film.

  FIG. 1 is a schematic view showing in cross section an example of a printing process for forming a light emitting portion by a relief printing method. Ink 5 obtained by dissolving or dispersing an organic EL material or the like in a solvent is transferred in the order of anilox roll 6, image forming portion of printing relief plate 8, and substrate 2, and desired light emission is formed on the light emitting portion formed thereon. Part is formed.

  FIG. 2 is a schematic view showing an example of a partition wall substrate used in a color display device such as a display in a plan view. In the partition substrate, a partition region is provided on the substrate, and pixel regions are defined as light emitting regions of the respective colors. Usually, a set of red light emitting pixel area 10, green light emitting pixel area 11, and blue light emitting pixel area 12 is arranged in a matrix as pixels 13. The pixel area of each color is arranged in the short side direction of the pixel area, and the pixel area for light emission of the same color is arranged in the long side direction.

When producing an organic EL element on a partition substrate, usually, a relief plate having a stripe pattern composed of a plurality of linear patterns is used, and the long side direction of the pixel region, that is, the direction in which the printing direction and the stripe pattern are parallel to each other. By transferring the organic EL material, an organic EL film is formed in the same color light emitting pixel region row. FIG. 3 is a schematic diagram for explaining how printing is performed. 4A is a schematic diagram of the partition wall substrate after printing, FIG. 4B is a cross-sectional view of the partition wall substrate after printing, and FIG.
Shows the film thickness of the pixel region.

  The transfer of the organic EL material by the printing method is significantly affected by the surface properties of the transferred portion. Therefore, when printing is performed with a relief plate having a stripe pattern on a partition wall substrate having different surface properties between the partition walls and the pixel region, defects in film thickness and film shape are likely to occur. FIG. 5 is a schematic diagram for explaining the defect phenomenon. 5A is a schematic diagram of the partition wall substrate after printing, FIG. 5B is a cross-sectional view of the partition wall substrate after printing, and FIG. 5C shows the film thickness shape in the pixel. When the surface properties are greatly different between the partition walls and the pixel region, as shown in FIG. 5A, a difference occurs in the way in which the ink spreads between the pixels and the partition walls. As a result, as shown in FIG. 5B, the amount of ink transferred between the partition walls and adjacent pixels varies, and defects such as film thickness differences and film shape deviations occur between pixel areas. When the film formation is normally performed on the partition substrate, as shown in FIG. 4C, the film shape becomes the thinnest concave shape at the center, but when the above defects occur, As shown in FIG. 5C, the position of the thinnest part changes for each pixel.

  In addition, the above-described printing failure occurs more remarkably when the difference in height between the pixel area and the partition wall is large, because the influence of the difference in wetting and spreading of the ink increases. Further, when such a film defect occurs in a pixel, a difference occurs in the light emission intensity and life of each pixel, so that light emission unevenness is observed.

Japanese Patent Laid-Open No. 10-12377 JP 2001-93668 A JP 2001-155858 A

  The present invention has been made in order to solve the above-described problems, and relates to a method for manufacturing an organic EL element in which an organic light emitting layer is formed using a printing method. It is an object of the present invention to provide an organic EL device manufacturing method and an organic EL device that are less likely to cause film defects such as unevenness of light and have no light emission unevenness.

According to a first aspect of the present invention, there is provided at least one layer of a pixel electrode on a substrate, a partition wall defining the adjacent element electrodes as pixels which are subpixels, and an organic EL layer made of an organic compound in the pixel. In the method of manufacturing an organic EL element formed by letterpress printing,
The pattern of the printing relief plate used for the patterning is a stripe or dot pattern, and the acute angle θ is 45 ° or more and 90 ° or less among the angles formed by the direction of the long side of the pattern and the printing direction. It is the manufacturing method of the organic EL element which makes it.

  The invention according to claim 2 of the present invention is the method for manufacturing an organic EL element according to claim 1, wherein the short side direction of the pattern is parallel to the short side direction of the pixel. is there.

  The invention according to claim 3 of the present invention is characterized in that the organic EL layer transferred in the pattern is formed to be connected in the long side direction of at least two or more pixels. 2 is a method for producing an organic EL device described in 2.

  In the invention according to claim 4 of the present invention, the organic EL layer transferred in the pattern is formed on both the partition and the pixel. It is a manufacturing method of the organic EL element described in item 1.

  Further, in the invention according to claim 5 of the present invention, the short side width of the previous pattern is 20 μm or more and 100 μm or less, The manufacture of the organic EL element according to any one of claims 1 to 4 Is the method.

  The invention according to claim 6 of the present invention is characterized in that the partition width in the long side direction of the adjacent pixels is 10 μm or more and not more than the pixel long side distance. It is a manufacturing method of the organic EL element to describe.

  In the invention according to claim 7 of the present invention, a difference in height between the partition wall and the pixel electrode is 0.1 μm or more and 5 μm or less. It is a manufacturing method of an organic EL element.

  The invention according to claim 8 of the present invention is characterized in that at least one of the organic EL layers to be printed is the lowest layer of the organic EL layers formed by a wet coating method. It is a manufacturing method of the organic EL element as described in 1-4.

  Next, an invention according to claim 9 of the present invention is an organic EL element manufactured by using the method for manufacturing an organic EL element according to any one of claims 1 to 8.

  Next, an invention according to claim 10 of the present invention is an organic EL display including the organic EL element according to claim 9.

  The invention according to claim 11 of the present invention is an organic EL illumination comprising the organic EL element according to claim 9.

  According to a twelfth aspect of the present invention, there is provided a pixel electrode on a substrate, a partition that defines the adjacent element electrodes as pixels that are subpixels, and an organic EL layer made of an organic compound in the pixel. In the method of manufacturing an organic EL element, in which at least one layer is formed by a relief printing method, the printing relief pattern used for the patterning is a stripe or a dot pattern, and a long side of the pattern and a printing direction are formed. Among the angles, the acute angle θ is 45 ° or more and 90 ° or less, and the organic EL device manufacturing apparatus is characterized in that

  According to the present invention, an organic EL film can be formed on a pixel and a partition having different surface properties without causing film defects such as film thickness differences and film shape deviations between pixels. The EL element can be manufactured by a printing method.

It is a schematic sectional drawing which shows an example of the printing apparatus used by the relief printing method based on this invention. It is explanatory drawing which shows an example of the partition board | substrate based on this invention in the plane. It is explanatory drawing which shows the mode of an example of the conventional printing process. It is explanatory drawing which shows an example of the partition board | substrate after the conventional printing. It is explanatory drawing which shows an example of the defect phenomenon of the partition board | substrate after the conventional printing. It is a schematic diagram which shows one embodiment of the relief printing plate concerning this invention in a cross section. It is explanatory drawing which shows the mode of an example of the printing process which concerns on this invention. It is explanatory drawing which shows a mode by the top view of an example of the printing process which concerns on this invention. It is explanatory drawing which shows one embodiment of the partition board | substrate printed by the manufacturing method of this invention. It is explanatory drawing which shows one embodiment of the board | substrate which printed with the manufacturing method of this invention. It is explanatory drawing which shows the other example of one Embodiment of the board | substrate which printed by the manufacturing method of this invention. It is sectional drawing which shows one Embodiment of the organic EL element which concerns on this invention. 1 is a cross-sectional view of an embodiment of an active matrix substrate used for manufacturing an organic EL element according to the present invention.

  Hereinafter, the manufacturing method of the organic EL element of this invention is demonstrated with reference to drawings based on the one embodiment. The present invention is not limited to this.

  The organic EL device manufacturing method of the present invention uses an ink in which at least one of a light emitting layer made of an organic material and a light emitting auxiliary layer made of an organic material is dissolved or dispersed in a solvent. It can be applied when forming by a relief printing method using a resin relief plate having a projection pattern made of a resin as a printing plate. As the light emission auxiliary layer, a hole transport layer, a hole injection layer, an electron transport layer, an electron injection layer, a charge generation layer, and the like are stacked and used. Hereinafter, in the present invention, a case where an organic EL material ink in which an organic EL material is dissolved or dispersed in a solvent is used will be described.

  An example of a conventional printing process is shown in FIG. 3, and an example of a printing process according to the present invention is shown in FIG. The letterpress for printing uses either a letterpress having a stripe pattern corresponding to a plurality of pixel arrangements (hereinafter simply referred to as a letterpress stripe pattern) or a dot pattern version having a plurality of short stripe patterns. can do.

  However, the dot pattern has a higher level of unevenness when supplying ink due to the high alignment accuracy required for each pattern and the inability to flow ink on the protrusions compared to the case of using a stripe pattern. There are disadvantages such as appearing.

  When the stripe pattern is used, a plurality of pixels can be printed in one pattern, which is advantageous in comparison with the dot pattern in terms of alignment accuracy and ink uniformity on the convex portion. However, the transfer of the organic EL material by the printing method is remarkably affected by the surface properties of the transferred portion, and when printing is performed on the partition substrate, there is a difference in how the ink spreads between the pixel and the partition, and the pixel Differences in film thickness between regions and uneven film shapes are likely to occur.

Here, the partition wall is formed so as to partition a light emitting region corresponding to a pixel (subpixel) by surrounding the periphery of the pixel electrode. That is, in the present invention, subpixel = (light emitting area + partition defining the light emitting area). In order to obtain a high-definition display, the short side width of the pixel (subpixel) is in the range of 20 μm to 100 μm. If it is less than 20 μm, it is difficult to manufacture with the relief printing method with accuracy, and if it exceeds 100 μm, the desired display quality cannot be obtained. The partition wall is formed so as to cover the end portion (side surface) of the pixel electrode so that each pixel occupies as large an area as possible. The partition wall width is 10 μm or more and less than the distance in the long side direction of the pixel. Within range. If the partition wall width is less than 10 μm, the pixel separation is insufficient and the display contrast is insufficient, and if the distance in the long side direction of the pixel is exceeded, the light emitting pixel region is narrowed. Moreover, the suitable height of a partition is in the range of 0.1 micrometer or more and 5 micrometers or less, More preferably, it exists in the range of 0.5 micrometer or more and 2 micrometers or less. The reason is that if the height of the partition wall is too high, formation and sealing of the second electrode (counter electrode) is hindered, and if the height of the partition wall is too low, the end of the pixel electrode cannot be covered, Further, this is because the adjacent pixels are mixed when forming the light emitting medium layer.

Here, the applicant of the present application has the effect of reducing the occurrence of unevenness due to the deviation due to the difference in wetting and spreading of the ink when the acute angle θ is 45 ° or more and 90 ° or less among the angles formed by the printing direction and the stripe pattern direction. I found it to work. This is because the ink transferred onto the substrate is leveled with the ink already applied, but if the angle between the printing direction and the stripe pattern direction is almost parallel, the ink in the vicinity where the stripe pattern and the substrate are in contact with each other Can only be leveled. On the other hand, when the angle formed by the printing direction and the stripe pattern direction is close to orthogonal, the portion where the stripe pattern and the substrate are in contact is equal to the entire length of the transfer pattern, so that the entire transfer pattern can be leveled.
In addition, when the angle between the printing direction and the stripe pattern direction is almost parallel, the ink on the stripe pattern is gradually pushed out as printing progresses, so a larger amount is printed on the plate just before the end of printing than at the start of printing. Remains, and is recognized as uneven light emission due to the film thickness becoming thicker on the printing end side. On the other hand, when the angle formed by the printing direction and the stripe pattern direction is close to orthogonal, the above-described ink is not gradually pushed out, so that unevenness does not occur.

As described above, in the present invention, by forming an angle (45 ° or more and 90 ° or less) in the stripe pattern direction with respect to the printing direction, a film thickness difference between pixel regions due to the influence of a partition wall or a deviation in film shape is defective. This is to mitigate the occurrence. A top view of an example of the printing process according to the present invention is shown in FIG. However, the closer the printing direction and the stripe pattern direction are to the orthogonality (90 °), the stronger the effect of the present invention appears.
On the other hand, when the acute angle θ is less than 45 ° among the angles formed by the print direction and the stripe pattern direction, the print direction and the stripe pattern are close to each other as shown in FIG. 3, which is the conventional print direction. Therefore, it becomes difficult to obtain the effect of reducing the unevenness of the present invention.

  Furthermore, in the present invention, FIG. 10 is an explanatory diagram of printing when the short side width of the stripe pattern is narrow, and FIG. 11 is an explanatory diagram when the short side width is wide. When the short side width of the pattern is wide, a film thickness difference occurs from the front side to the rear side with respect to the printing direction. Therefore, in the present invention, it is desirable that the short side width of the stripe pattern is 100 μm or less in combination with the above-described pixel definition. However, there is no need to limit if the above-mentioned defects can be prevented by adjusting process parameters, materials, and ink.

  FIG. 1 shows a schematic diagram of an example relief printing apparatus used for producing printed matter according to the present invention. The printing substrate 2 is fixed to the stage 1, the printing relief plate 8 patterned according to the present invention is fixed to the plate cylinder 7, and the printing relief plate is in contact with the anilox roll 6 which is an ink supply, The anilox roll includes an ink replenishing device 3 and a doctor 4.

  First, the ink 5 is replenished from the ink replenishing device 3 to the anilox roll 6, and excess ink out of the ink 5 supplied to the anilox roll 6 is removed by the doctor 4. Any ink replenishing device 3 may be selected as long as the anilox roll is appropriately refilled with ink. Moreover, as long as the excess ink is appropriately removed, the doctor 4 may be selected from a doctor roll or the like.

  The ink 5 uniformly held by the doctor 4 on the surface of the anilox roll which is an ink supply body to the printing relief plate 8 is transferred and supplied to the convex pattern of the printing relief plate 8 attached to the plate cylinder 7. Then, the convex pattern of the printing relief plate 8 and the substrate 2 move relatively in contact with the rotation of the plate cylinder, and the ink 5 is transferred to a predetermined position of the printing substrate 2 on the stage 1 to be printed. Then, a transfer pattern 9 is formed. After the pattern formation, a drying process using an oven or the like can be provided as necessary.

  FIG. 1 shows a sheet-fed letterpress printing apparatus that forms an ink pattern on a substrate to be printed one by one. However, if the substrate to be printed is compatible, a roll-to-roll letterpress printing apparatus is used. It can also be used. Further, the printing relief plate may be used in the form of a flat relief plate instead of being wound around the plate cylinder.

  FIG. 6 shows an explanatory cross-sectional view of one embodiment of the relief printing plate according to the present invention. A convex pattern 15 formed of a resin layer is formed on the plate substrate 16. The plate base material may be a laminate by adding a layer for imparting functionality such as a visible light reflection preventing effect between the convex pattern and the plate base material as necessary.

  In the plate material used for the printing relief plate according to the present invention, as the plate substrate on which the convex pattern is formed, it is only necessary to have mechanical strength against printing, and a synthetic resin, a metal, or a laminate thereof is used. Among them, those that maintain dimensional stability are desirable.

  The polymer that is one component of the resin that forms the convex pattern of the printing relief printing plate according to the present invention can be selected from one or more types of synthetic resins, copolymers thereof, natural polymers such as cellulose, etc. When applying a coating solution such as an organic light emitting material, a fluororesin is desirable from the viewpoint of solvent resistance to organic solvents.

  In addition, by containing at least one kind soluble in water-soluble solvents such as polyvinyl alcohol, polyamide, polyurethane, cellulose acetate succinate, partially saponified polyvinyl acetate, cationic piperazine-containing polyamide and derivatives thereof Since it is possible to impart solvent resistance, it is also desirable to select and use one or more of these.

  For the convex pattern by the resin layer in the production method of the present invention, various pattern molding methods such as a photolithography method and a printing method can be used. From the viewpoint of high definition of the pattern, photolithography using a photosensitive resin is possible. The law is desirable.

  When applying a photolithographic method using a photosensitive resin as a method for forming convex portions, a convex pattern of a relief printing plate is formed from a plate-shaped photosensitive resin laminate in which a base material layer and a photosensitive resin layer are sequentially laminated. It is most desirable to do. A known method can be used as a method for molding the photosensitive resin layer.

  The molding method of the plate-shaped photosensitive resin laminated body which concerns on this invention is shown. When an antireflection layer or the like is formed on a substrate, a film is formed by a wet coating method or a dry coating method to form a laminate. Next, a photosensitive resin layer is formed on the laminate or substrate by a known method to obtain a plate-like photosensitive resin laminate.

  A photolithography method is used for the formed plate-shaped photosensitive resin laminate, and a desired convex pattern is formed through known exposure and development processes.

Next, an example of the manufacturing process of the organic EL element using the partition board | substrate by this invention is demonstrated. FIG. 12 shows an example of an organic EL element according to the present invention, and FIG. 13 shows an explanatory sectional view of an example of a partition wall substrate according to the present invention. Note that the present invention is not limited to this, and by forming a thin transistor (TFT) 34 on a substrate, an active matrix organic EL element substrate can be obtained. The drive system of the present invention is not limited to the active matrix.

  The TFT and its upper layer are supported by a support 25. The support is preferably excellent in mechanical strength and dimensional stability. Any substrate can be used as the support as long as it is an insulating substrate. In the case of a bottom emission type organic EL device that extracts light from the support side, it is necessary to use a transparent support.

  For example, a glass substrate or a quartz substrate can be used as the support. Further, when demanding flexibility, a plastic film or sheet may be used. A metal oxide thin film, a polymer resin film, or the like may be laminated for the purpose of preventing moisture and the like from entering these.

  As the TFT provided on the support, a known thin film transistor can be used. Specifically, a thin film transistor composed mainly of an active layer 26 in which a source / drain region and a channel region are formed, a gate insulating film 27 and a gate electrode 28 can be mentioned. The structure of the thin film transistor is not particularly limited.

  As the partition substrate for the organic EL element of the present invention, the planarization layer 31 is formed on the TFT, the lower electrode (first electrode 17) of the organic EL element is provided on the planarization layer, and It is preferable that the TFT and the first electrode 17 are electrically connected via a contact hole 32 provided in the planarization layer 31. By comprising in this way, the outstanding electroconductivity can be obtained between TFT and an organic EL element.

  The active layer 26 is not particularly limited, and can be formed of, for example, an inorganic semiconductor material such as amorphous silicon or polycrystalline silicon, or an organic semiconductor material such as thiophene oligomer.

As the gate insulating film 27, a film normally used as a gate insulating film can be used. For example, the gate insulating film 27 is obtained by thermally oxidizing a SiN, SiO ₂ or polysilicon film formed by a PECVD method, an LPCVD method or the like. SiO ₂ or the like can be used.

  As the gate electrode 28, those usually used as the gate electrode can be used, and examples thereof include aluminum, copper, titanium, tantalum, tungsten, polysilicon, silicide, and polycide.

  The display device needs to be connected so that the thin film transistor (TFT) functions as a switching element of the organic EL element, and the drain electrode 30 of the transistor and the pixel electrode (first electrode 17) of the organic EL element are electrically connected. Has been.

  The TFT, the drain electrode 30, and the pixel electrode (first electrode 17) of the organic EL element are connected through a connection wiring formed in a contact hole 32 that penetrates the planarization film 31.

Regarding the material of the planarizing film, inorganic materials such as SiO ₂ , spin-on glass, SiN (Si ₃ N ₄ ), TaO (Ta ₂ O ₅ ), organic materials such as polyimide resin, acrylic resin, photoresist material, and black matrix material Etc. can be used. The formation method is selected according to the material.

  A first electrode as a pixel electrode is provided on the substrate. When the first electrode is used as an anode, the material is a single layer or stacked layers of metal composite oxides such as ITO (indium tin composite oxide) and IZO (indium zinc composite oxide), and gold and chromium. Any of these can be used. The method for forming the first electrode is selected according to the material.

  ITO is preferably used because of its low resistance, solvent resistance, and high transparency when the bottom mission method is adopted. ITO is formed on a glass substrate by a sputtering method, and is patterned by a photolithography method to form a first electrode.

After the first electrode 17 is formed, the partition wall 14 is formed so as to cover the first electrode edge. The partition wall needs to have insulating properties, and a photosensitive material or the like can be used. The photosensitive material may be a positive type or a negative type, a photo-curing resin of a photo radical polymerization system, a photo cationic polymerization system, or a copolymer containing an acrylonitrile component, polyvinyl phenol, polyvinyl alcohol. , Novolac resin, polyimide resin, cyanoethyl pullulan, and the like can be used. Further, as a partition wall forming _material, it is also possible to use SiO 2, SiN, TiO ₂ or the like.

  When the partition wall forming material is a photosensitive material, the entire surface of the forming material solution is coated by a slit coating method or a spin coating method, and then patterning is performed by a photolithography method such as exposure and development. When the partition is formed by a photolithography method using a photosensitive material, its shape can be controlled by exposure and development conditions.

Further, when the partition wall forming material is SiO ₂ , SiN, TiO ₂ , it can be formed by a dry film forming method such as a sputtering method or a CVD method. In this case, patterning of the partition walls can be performed by a mask or a photolithography method.

  Next, an organic EL layer including a light emitting layer and a light emission auxiliary layer is formed. The organic EL layer sandwiched between the electrodes may be composed of a light emitting layer alone, or a light emission assisting layer such as a hole transport layer, a hole injection layer, an electron transport layer, an electron injection layer, or a charge generation layer. It is good also as a laminated structure which added the layer. In addition, the presence or absence of the light emission auxiliary layer is appropriately selected as necessary. The material used for each can be selected according to the characteristics.

  The organic EL material and the solvent for dissolving or dispersing the organic EL material may be any combination that can be converted into an ink, and are used alone or in combination depending on the characteristics. Moreover, you may add surfactant, a viscosity modifier, etc. to a solvent as needed.

  Next, the second electrode 22 is formed. When the second electrode is a cathode, a material having a high electron injection efficiency is used as the material. As a forming method, a dry film forming method such as a resistance heating evaporation method, an electron beam evaporation method, or a sputtering method can be used depending on the material. Moreover, when it is necessary to make a 2nd electrode into a pattern, it can pattern by a mask etc. In the present invention, the first electrode can be a cathode and the second electrode can be an anode.

  As an organic EL element, it is possible to emit light by sandwiching a light emitting layer between electrodes and passing an electric current. However, some organic EL materials and electrode forming materials are easily deteriorated by moisture and oxygen in the atmosphere. For this reason, a sealing body 24 is usually provided for shielding from the outside.

  The sealing body 24 includes, for example, a first electrode, an organic EL layer, a glass cap having a recess, and a metal cap with respect to the substrate on which the first electrode, the light emitting layer, the light emission auxiliary layer, and the second electrode are formed. Sealing is performed by adhering the glass cap and the substrate 2 with an adhesive 23 around the periphery of the second electrode so that the recess is in the air. As a passivation film, a silicon nitride film or the like is formed using a CVD method or the like, whereby a sealing body made of an inorganic thin film can be formed, or these can be combined.

  Specific examples of the present invention will be described below. The present invention is not limited to this.

<Example 1>
(Preparation of photosensitive resin letterpress)
A 42-mm nickel material with a thickness of 250 μm was used as a relief printing plate base material, and an acrylic binder resin solution kneaded with a black pigment was applied on the base material so as to have a dry film thickness of 10 μm and dried. A prevention layer was formed.

  Mainly water-soluble polyamide, dipentaerythritol hexakisacrylate as radical polymerizable monomer, 2,2-dimethoxy-1,2-diphenylethane-1-one as photopolymerization initiator (manufactured by Ciba Specialty Chemicals) ) Was kneaded and applied to the surface of the base material so that the total thickness of the plate material was 310 μm, which was used as the photosensitive resin layer. A polyethylene terephthalate film (film thickness 125 μm: manufactured by Teijin DuPont Films) coated with a polyvinyl alcohol solution so as to have a dry film thickness of 1 μm was laminated thereon.

  The resin relief printing plate was exposed using a synthetic quartz substrate chromium mask as the original plate of the resin relief pattern, and this mask was set in a proximity exposure apparatus, and a relief printing plate having a pattern shape as shown in FIG. 6 was produced. The produced convex width is 30 μm.

(Preparation of printed substrate)
As a substrate to be printed, a thin film transistor functioning as a switching element provided on a support, a planarization layer formed thereabove, and a pixel electrode that is connected to the thin film transistor by a contact hole in the form of a planarization layer An active matrix substrate provided with One side of the pixel size is 150 μm square, and the size of the RGB sub-pixel is 50 × 150 μm.

  A partition wall was formed so as to cover the end of the pixel electrode provided on the active matrix substrate and partition the pixel. The partition is formed by applying a positive resist ZWD6216-6 manufactured by ZEON Corporation on the entire surface of the active matrix substrate with a spin coater so that the dry thickness is 2 μm, and then by photolithography in the short side direction of each adjacent subpixel. A partition wall having a line width of 25 μm and a line width of 75 μm was formed in the long side direction. At this time, the aperture ratio is 25%.

  A poly- (3,4) -ethylenedioxythiophene / polystyrene sulfonic acid (PEDOT / PSS) 1.5 mass% aqueous solution is applied as a hole transport layer on the pixel electrode by a spin coat method, and the film thickness is 100 nm. The film was formed. Further, the PEDOT / PSS thin film thus formed was dried at 100 ° C. for 1 hour under reduced pressure to produce a substrate to be printed.

(Preparation of ink for forming an organic light emitting layer)
The following organic luminescent inks consisting of three colors of red, green and blue (R, G, B) were prepared by dissolving in xylene. The red light-emitting ink (R) is a toluene solution of a polyfluorene derivative (red light-emitting material manufactured by Sumitomo Chemical Co., Ltd., trade name Red 1100). The green light emitting ink (G) is a toluene solution of a polyfluorene derivative (green light emitting material manufactured by Sumitomo Chemical Co., Ltd., trade name Green 1300). The blue light emitting ink (B) is a toluene solution of a polyfluorene derivative (blue light emitting material manufactured by Sumitomo Chemical Co., Ltd., trade name Blue 1100). The viscosity of each ink solution is approximately 40 mPa · s.

(Printing process)
The relief printing plate was fixed to the plate cylinder of a sheet-fed relief printing press. Next, the organic light-emitting ink is supplied to an ink tank of a relief printing press, coated on a 600 line / 2.54 cm honeycomb anilox roll from the ink discharge section, scraped with a doctor, and then printed on the relief printing plate. The convex part was inked. Further, the inked printing relief plate was pressed against the substrate to be printed and rolled to print a stripe pattern on the substrate to be printed. At that time, the stripe pattern was orthogonal to the printing direction. By repeating this step for each of the red organic light emitting layer, the green organic light emitting layer, and the blue organic light emitting layer, an organic light emitting layer pattern was obtained. After printing for each color, drying was performed in an oven at 130 ° C. for 1 hour.

  After drying, a 10 nm calcium film is formed on the organic light-emitting layer formed by printing, and then silver is vacuum-deposited by 300 nm thereon, and finally sealing is performed using a glass cap. Was made.

<Example 2>
As Example 2, an organic EL element was produced in the same manner as Example 1 except that the angle θ between the stripe pattern and the printing direction was 45 °.

<Example 3>
As Example 3, an organic EL element was produced in the same manner as Example 1 except that the angle θ between the stripe pattern and the printing direction was 60 °.

<Example 4>
As Example 4, an organic EL device was produced in the same manner as in Example 1 except that the partition wall width in the long side direction of adjacent subpixels was set to 5 μm.
An element was produced.

<Example 5>
As Example 5, an organic EL element was produced in the same manner as in Example 1 except that the partition wall height was 0.05 μm.

<Comparative Example 1>
As Comparative Example 1, an organic EL element was produced in the same manner as in Example 1 except that the stripe pattern was parallel to the printing direction.

<Comparative example 2>
As Comparative Example 2, an organic EL element was produced in the same manner as in Example 1 except that the stripe pattern and the printing direction angle θ were 30 °.

  Tables 1 to 5 and Comparative Examples 1 and 2 show the results of measurement of film thickness measurement results at 10 points in the panel surface of the manufactured organic EL elements, film shape observation results, and lighting display characteristics. Shown in

  According to Table 1, when the acute angle θ is not 45 ° or more and 90 ° or less among the angles formed by the printing direction and the stripe pattern direction from the comparison between Examples 1 to 5 and Comparative Examples 1 and 2, the film thickness variation value is It can be seen that deterioration and film shape defects occur, resulting in uneven light emission. Further, from the comparison of the results of the examples, it is desirable that the acute angle θ is closer to 90 °, the short side width of the stripe pattern is desirably 100 μm or less, the wider partition wall is desirable, and the partition wall height is higher. It turns out that is better.

1 ... Stage
2 ... Board
3 ... Ink replenisher
4 ... Doctor
5 ... Ink
6 ... Anilox roll
7 ... plate cylinder
8 ... Letter for printing
9 ... Transfer pattern
10 ... 1st pixel
11 ... second pixel
12 ... Third pixel
13 ... Pixel 14 ... Partition
15 ... Plate base material
16 ... convex part
17 ... 1st electrode
18 ... Hole transport layer
19 ... Red light emitting layer
20 ... Green light emitting layer
21 ... Blue light emitting layer
22 ... Second electrode
23 ... Adhesive
24 ... Sealing body
25 ... Support
26 ... Active layer
27 ... Gate insulating film
28 ... Gate electrode
29 ... Transistor insulating film
30 ... Drain electrode
31 ... Planarization layer
32 ... Contact hole
33 Scanning line
34 ... TFT

Claims (12)

An organic material formed by forming a pixel electrode on a substrate, at least one layer of an organic EL layer made of an organic compound on the pixel by a relief printing method, and a partition wall that defines the adjacent element electrodes as sub-pixel pixels. In the method for manufacturing an EL element,
The pattern of the relief printing plate used for the patterning is a stripe or dot pattern,
Of the angles formed by the direction of the long side of the pattern and the printing direction, the acute angle θ is 45 ° or more and 90 ° or less, and the method for manufacturing an organic EL element.   2. The method of manufacturing an organic EL element according to claim 1, wherein a short side direction of the pattern is parallel to a short side direction of the pixel.   3. The method of manufacturing an organic EL element according to claim 1, wherein the organic EL layer transferred in the pattern is formed to be connected in a long side direction of at least two or more pixels. 4.   4. The method of manufacturing an organic EL element according to claim 1, wherein the organic EL layer transferred in the pattern is formed on both the partition and the pixel. 5.   5. The method of manufacturing an organic EL element according to claim 1, wherein a short side width of the pattern is 20 μm or more and 100 μm or less.   6. The method of manufacturing an organic EL element according to claim 1, wherein a partition wall width in a long side direction of the adjacent pixels is 10 μm or more and a pixel long side distance or less.   7. The method of manufacturing an organic EL element according to claim 1, wherein a difference in height between the partition wall and the pixel electrode is 0.1 μm or more and 5 μm or less.   5. The method of manufacturing an organic EL element according to claim 1, wherein at least one layer of the organic EL layer to be printed is a lowermost layer of the organic EL layers formed by a wet coat method.   An organic EL device manufactured using the method for manufacturing an organic EL device according to claim 1.   An organic EL display comprising the organic EL element according to claim 9.   An organic EL illumination comprising the organic EL element according to claim 9. An organic material formed by forming a pixel electrode on a substrate, at least one layer of an organic EL layer made of an organic compound on the pixel by a relief printing method, and a partition wall that defines the adjacent element electrodes as sub-pixel pixels. In the method for manufacturing an EL element,
The pattern of the relief printing plate used for the patterning is a stripe or dot pattern,
Of the angles formed by the long side of the pattern and the printing direction, the acute angle θ is 45 ° or more and 90 ° or less, and the organic EL element manufacturing apparatus.

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