JP2009099440A - Manufacturing method of organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method capable of stably forming a printing pattern of excellent pattern accuracy by easily clarifying a relation between a pixel shape of a barrier-rib substrate suited for printing conditions and a printing method, in forming an organic functional element by a letterpress printing method. <P>SOLUTION: In the manufacturing method of an organic electroluminescent element with an organic light-emitting medium layer formed at an opening of barrier ribs, at least one layer of the organic light-emitting medium layer with a pixel area of the substrate surrounding a periphery of the pixels with the barrier ribs in a lattice shape of a rectangular shape having long sides and short sides is sequentially formed in printing in a long-side direction of the pixel area by rotating a plate cylinder with the letterpress arranged. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a high-definition display, and more specifically, an ink material is patterned on a printing medium such as a substrate for producing precision parts such as organic electroluminescence (EL) elements by a relief printing method. The present invention relates to a method for printing and manufacturing a high-definition display.

  In general, an organic EL element is one in which an organic light-emitting layer made of an organic light-emitting material is formed between two opposing electrode substrates, and light is emitted by passing a current through the organic light-emitting layer. In order to achieve this, it is important to control the film thickness of the organic light emitting layer. For example, it is necessary to form a very thin film with a film thickness of about 100 nm. Furthermore, in order to make this a display, it is necessary to pattern with high definition.

  Organic light-emitting materials formed on a substrate or the like include a low molecular material and a polymer material. In general, a low molecular material is formed into a thin film on a substrate by resistance heating vapor deposition (vacuum vapor deposition) or the like. Patterning is performed using a mask, but this method has a problem that patterning accuracy is difficult to obtain as the substrate becomes larger.

  Therefore, recently, there is a method in which a polymer material is used as an organic light emitting material to be formed on a substrate, etc., this organic light emitting material is dissolved in a solvent to form an ink and then a coating ink liquid is formed, and then a thin film is formed by a wet coating method. Attempts are being made. The wet coating method for forming a thin film includes a spin coating method, a bar coating method, a protruding coating method, a dip coating method, etc., but patterning with high definition, red (R), green (G), blue ( In order to separate the three colors B), it is difficult to use these wet coating methods, and it is considered most effective to form a thin film by pattern printing using a printing method that specializes in separate patterning.

  On the other hand, as a means for patterning an organic light emitting layer in order to achieve full color using a polymer light emitting material, a pattern forming method using an ink jet method and a pattern forming method using a printing plate are mainly employed. For example, in the pattern forming method by the ink jet method disclosed in JP-A-10-12377, a light emitting layer forming material dissolved in a solvent is ejected from an ink jet nozzle onto a substrate and dried on the substrate. This is a method for obtaining a desired pattern.

  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.

  On the other hand, for example, in Japanese Patent Laid-Open No. 2002-305077, a bank is formed in advance on a substrate by a material having ink repellency by photolithography and the like, and ink droplets are landed on the bank, thereby Discloses a method in which ink is repelled to obtain a linear pattern. However, when the ink repelled in the bank portion returns to the inside of the pixel, there is a problem that the thickness of the organic light emitting layer in the pixel varies depending on the inside of the pixel.

  Therefore, instead of low-molecular-weight organic light-emitting materials, polymer-based organic light-emitting materials are dissolved or dispersed in a solvent to make ink, and this ink is used for printing methods such as letterpress printing, reverse printing, and screen printing. A patterning method has been proposed. In particular, the method using relief printing is excellent in pattern formation accuracy, film thickness uniformity, and the like, and is suitable as a method for producing an organic electroluminescence element by printing.

  Furthermore, among various printing methods, organic EL elements and displays often use a glass substrate as a substrate, so that a method using a hard plate such as a metal printing plate such as a gravure printing method is not suitable. For this purpose, printing methods using elastic rubber printing plates, offset printing methods using rubber printing blankets, and photosensitive resin plates based on elastic rubber and other resins are used. The letterpress printing method used can be adopted as an appropriate printing method. Actually, as a trial of these printing methods, a pattern printing method by offset printing (Patent Literature 1), a pattern printing method by letterpress printing (Patent Literatures 2 and 3), and the like have been proposed.

  Production of an organic electroluminescence element by such a relief printing method is performed as follows. That is, first, a high molecular weight organic light emitting material is dissolved or dispersed in a solvent to form an ink, which is then applied to the roll surface of an anilox roll having fine square or hexagonal lattice matrix regular holes. Next, the ink amount per unit area of the anilox roll is made uniform by scraping off the excess ink on the surface of the anilox roll with a doctor blade. Then, the ink on the anilox roll is transferred to the convex portion of the plate 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 electroluminescence element, and finally, this printing plate The organic light emitting layer is formed by transferring the ink thin film on the image forming part of the substrate onto the substrate.

  Next, the board | substrate used as a to-be-printed material is demonstrated. The substrate already includes a pixel electrode (first electrode 2), an extraction electrode, an insulating layer made of a SiNx film for protecting the TFT circuit, and an insulating layer made of polyimide, and the insulating layer made of polyimide partitions the pixels. Is formed.

  The pixel portion of the substrate is surrounded by steps with an insulating layer made of polyimide, and when an organic functional material is formed into a high-definition stripe of 50 to 400 ppi by a printing method, it is in a direction perpendicular to the printing direction. If the partition walls are high and the pixel width is narrow with respect to the printing direction, the convex portions of the plate do not contact the pixel portions of the substrate, and ink transfer becomes impossible. In addition, the height of the partition wall is sufficient for the pixels to come into contact, and even if the relief plate is in contact with the substrate pixel portion, the area and time of contact between the pixel portion and the plate are not sufficient to some extent in the printing progress direction. Therefore, it is difficult to uniformly pattern the pixels.

  On the other hand, in the method of printing the pattern on the plate in the form of dots and printing directly only on the pixel part, it can be transferred only to the pixel part, but with high-definition patterning, the amount of ink on the plate after the transfer from the anilox to the plate is reduced. Since it is reduced, it is greatly affected by drying and the like, and the shape of the inner film of the pixel is deteriorated, so that the uniformity of the entire panel does not appear.

  In addition, there is a method of slowing the rolling speed of the plate cylinder in order to lengthen the transfer time, but there has been a problem that the production throughput is slowed and the productivity efficiency is lowered.

Related patent documents are listed below.
JP 2001-189192 A JP 2007-258145 A

  When organic functional elements are formed by letterpress printing, the relationship between the printing method and the pixel shape of the barrier rib substrate that is suitable for printing conditions is easily clarified to form a stable and highly accurate printing pattern. A manufacturing method is provided.

  The invention according to claim 1, which has been made to solve the above-mentioned problems, is a method of manufacturing an organic electroluminescent element in which an organic light emitting medium layer is formed in an opening of a partition, wherein the periphery of the pixel is formed on the lattice by the partition The pixel region of the substrate surrounded by the rectangle is a rectangle having a long side and a short side, and at least one organic light emitting medium layer is sequentially printed in the long side direction of the pixel region by rotating the plate cylinder on which the relief plate is arranged. This is a method for producing an organic electroluminescence element. By printing along the long side direction of the pixel, the contact time between the substrate and the plate can be maintained longer, and when printing is performed by rotating the plate cylinder on a flat plate, the longer the width of the opening, the more the plate surface and print Since the distance to the surface can be reduced, good transfer can be performed.

  The invention according to claim 2 is the method for manufacturing an electroluminescent element according to claim 1, wherein the relief plate has a striped surface pattern parallel to the long side direction. Since the partition is included, the organic layer can be formed only in the opening, and the surface pattern is striped, so that the alignment is easy.

  According to a third aspect of the present invention, when the length of the short side of the pixel region is a and the width of the partition wall in the short side direction is c, the line width x of the relief plate satisfies a <x <a + c. It is a manufacturing method of the electroluminescent element of Claim 2 characterized by the above-mentioned. As a result, a sufficient amount of ink is secured, so that a uniform pattern can be formed over the entire pixel area.In addition, even when the plate is shifted to the margin of the pixel width on one of the adjacent pixels, ink is applied to the adjacent pixels. Since it does not flow in, the tolerance of alignment spreads and alignment becomes easy.

  According to a fourth aspect of the present invention, in the organic electroluminescence device according to any one of the first to third aspects, the height of the partition perpendicular to the printing direction of the substrate is 0.5 to 5 μm. Is the method. Thereby, the contact between the pixel of the substrate and the convex portion of the plate can be sufficiently achieved.

  The invention according to claim 5 is a method for producing an organic EL display, wherein the resolution of the display using the organic electroluminescent element according to any one of claims 1 to 4 is in the range of 50 ppi to 400 ppi. It is. Thereby, an organic EL display having excellent quality can be manufactured.

  According to the manufacturing method of the present invention, since the long side and the short side of the pixel are appropriately set and the printing direction and the long side direction of the pixel are parallel, the top surface of the convex portion of the printing relief printing plate is drawn. Make sufficient contact with the part. For this reason, the ink can be uniformly patterned in the pixel with high definition without unevenness, and there is an effect that high-definition organic electroluminescence excellent in uniformity without defects can be obtained.

<Organic EL device>
The organic EL element of the present invention will be described. In addition, the organic EL element which concerns on this invention, and its manufacturing method are not limited to implementation demonstrated below. Hereinafter, an example in which the present embodiment is applied to an active matrix driving type organic EL display panel will be described. As a driving method of the organic EL element, there are a passive matrix and an active matrix. However, the organic EL element in this embodiment can be applied to either a passive matrix type or an active matrix type organic EL element.

  Moreover, the organic EL element of the present invention can be applied to both the substrate side and the sealing side in the light extraction direction. That is, the organic EL element of the present invention can be applied to both a bottom emission type organic EL element that extracts light emitted from the substrate side and a top emission type organic EL element that extracts light emitted from the opposite side of the substrate. is there. Furthermore, the organic EL element of the present invention can also be applied to a transparent organic EL element that extracts light emitted from both sides.

In the present invention, an organic EL element substrate is provided with a substrate, a pixel electrode, an organic light emitting medium layer including an organic light emitting layer, and a counter electrode on the substrate. Moreover, what was sealed by providing a water vapor | steam barrier layer etc. on this organic EL element board | substrate as needed, and sticking the sealing base material and the organic EL element board | substrate through the adhesive agent with an organic EL element. To do. FIG. 1 shows an explanatory cross-sectional view of the organic EL element substrate of the present invention.

  As shown in FIG. 1, the organic EL display panel has a first electrode 2 as an anode on a TFT substrate 1. The partition wall 7 is provided between the first electrodes 2 and preferably covers the end portion of the first electrode 2 for the purpose of preventing a short circuit due to burrs or the like at the end portion of the first electrode 2.

  The organic EL display panel has an organic light emitting layer and a light emission auxiliary layer on the first electrode 2 and in a region (light emitting region L, pixel portion) partitioned by the partition walls 7. The layer sandwiched between the electrodes may be composed of an organic light emitting layer alone, or may be composed of a laminated structure of an organic light emitting layer and a light emission auxiliary layer. Examples of the light emission auxiliary layer include a hole transport layer, a hole injection layer, an electron transport layer, and an electron injection layer. In FIG. 1, the structure which consists of a laminated structure of the positive hole transport layer 3 which is a light emission auxiliary layer, and an organic light emitting layer (41, 42, 43) is shown. A hole transport layer 3 is provided on the first electrode 2, and a red (R) organic light-emitting layer 41, a green (G) organic light-emitting layer 42, and a blue (B) organic light-emitting layer 43 are provided on the hole transport layer 3. Is provided. In the present embodiment, the plurality (three in the example) of organic light emitting layers 41, 42, and 43 can be formed by the pattern forming method according to the present invention as described later.

  Next, the 2nd electrode 5 is arrange | positioned as a cathode (cathode layer) so as to oppose the 1st electrode 2 which is an anode on an organic luminescent medium layer. The second electrode 5 is formed on the entire surface of the organic EL display panel. Further, in order to prevent moisture and oxygen in the environment from entering the first electrode 2, the organic light emitting layers 41, 42, 43, the light emitting auxiliary layer, and the second electrode 5, the entire effective pixel is sealed with a glass cap 8 or the like. A body is provided and bonded to the TFT substrate 1 via an adhesive 9.

Next, the TFT substrate 1 will be described.
FIG. 2 is an explanatory cross-sectional view of the TFT substrate 1. The TFT substrate 1 has a planarization layer 117 formed on a TFT (thin film transistor) 120, and a lower electrode (first electrode 2) of an organic EL display panel is provided on the planarization layer 117, and The TFT 120 and the lower electrode are preferably electrically connected via a contact hole 118 provided in the planarization layer 117. With this configuration, excellent electrical insulation can be obtained between the TFT 120 and the organic light emitting medium layer (hole transport layer 3, organic light emitting layers 41, 42, 43).

  The TFT 120 and the portion formed above the TFT 120 are supported by a support 111. The support is preferably excellent in mechanical strength and dimensional stability. As a material of the support 111, for example, a glass substrate or a quartz substrate can be used. Further, it may be a plastic film or sheet such as polypropylene, polyethersulfone, polycarbonate, cycloolefin polymer, polyarylate, polyamide, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate. Metal oxide thin film, metal fluoride thin film, metal nitride thin film, metal oxynitride thin film, or polymer resin film for the purpose of preventing moisture from entering the organic light emitting medium layer in these plastic films and sheets You may utilize what laminated | stacked.

  As the gate insulating film 113, a film normally used as a gate insulating film can be used. For example, SiO2 formed by PECVD, LPCVD, etc., SiO2 obtained by thermally oxidizing a polysilicon film, etc. Can be used.

  As the gate electrode 114, those normally used as the gate electrode can be used. For example, metals such as aluminum and copper, refractory metals such as titanium, tantalum and tungsten, polysilicon, silicide of refractory metals And polycide.

  The TFT 120 may have a single gate structure, a double gate structure, or a multi-gate structure having three or more gate electrodes. Moreover, you may have a LDD structure and an offset structure. Further, two or more thin film transistors may be arranged in one pixel.

  The thin film transistor (TFT) needs to be connected so as to function as a switching element of the organic EL display panel, and the drain electrode 116 of the transistor and the pixel electrode (first electrode 2) of the organic EL display panel are electrically connected. Has been. Further, it is generally necessary to use a metal that reflects light as a pixel electrode for taking a top emission structure.

  The TFT 120, the drain electrode 116, and the pixel electrode (first electrode 2) of the organic EL display panel are connected through a connection wiring formed in a contact hole 118 that penetrates the planarization film 117.

Regarding the material of the planarizing film 117, 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 are used. Materials and the like can be used. Spin coating, CVD, vapor deposition, etc. can be selected according to these materials. If necessary, contact holes 118 are formed by dry etching, wet etching, or the like at a position corresponding to the lower TFT 120 after photolithography using a photosensitive resin as a planarizing layer, or once the planarizing layer is formed on the entire surface. Form. The contact hole is then filled with a conductive material to establish conduction with the pixel electrode formed in the upper layer of the planarization layer. The thickness of the planarizing layer is not limited as long as it can cover the lower TFT, capacitor, wiring, etc., and the thickness may be several μm, for example, about 3 μm.

  As shown in FIG. 3, the aperture pixel is a rectangle whose peripheral portion is surrounded by a partition wall 7 on the lattice. When the short side and the long side are a and b, respectively, a / b is 0.95 to 0. It is preferable to have a pixel pattern that is in the range of 1. Moreover, it is preferable that the height of the partition wall 7 orthogonal to the printing direction of the substrate is 0.5 to 5 μm. This is because the contact between the pixel of the substrate and the convex portion of the plate can be sufficiently achieved.

<Method for forming organic EL element>
Next, a method for forming an organic EL element by forming an organic light emitting medium layer, a cathode, and a sealing layer on the TFT substrate 1 will be described.

  In the TFT substrate 1 used in the present invention, each pixel is partitioned by a partition 7 made of an insulating material such as polyimide, and thus has an independent matrix-like opening on the pixel electrode (first electrode 2). Become. In the present invention, at least one organic light emitting medium layer is formed on the opening pixel using a relief printing method.

  One of the features of the method for producing an organic EL element of the present invention is that the organic layer is sequentially printed in the long side direction of the pixel as shown in FIG. This is because printing can be continued for a longer time by printing along the long side direction of the pixel, and when printing is performed by rotating the plate cylinder on a flat plate, the width of the opening is longer. This is because a good transfer can be performed because the distance between the printing plate and the printing surface can be reduced. In other words, in producing a high-definition display in the range of 50 to 400 ppi, in order to transfer a sufficient amount uniformly from the relief plate to the pixels, when the plate rolls and contacts the substrate, This is achieved by maintaining the contact time and distance with the pixel to some extent. For this purpose, the shape of a rectangular pixel having a long side parallel to the printing direction is considered to be the best.

  Furthermore, in the present invention, as shown in FIG. 3 (a), an organic light emitting medium layer pattern is printed and formed on the matrix-shaped opening pixel with a relief plate having a striped surface pattern. . Since the partition is included, the organic layer can be formed only in the opening, and the surface pattern is striped, so that the alignment is easy. In particular, when a full-color organic EL display is manufactured, the organic light-emitting layer needs to be separately applied to each color pixel, so that the method of the present invention is effective. FIG. 4 shows the above aspect of the present invention.

  Further, when the width a of the short side of the pixel, the partition wall width c in the direction of the short side, and the line width x of the striped relief pattern, the line width x has a relationship of a <x <a + c. Is desirable. Since the line width is larger than the pixel width in the printing direction, a sufficient amount of ink is secured, so that a uniform pattern can be formed over the entire pixel area. If the line width is smaller than the sum of the pixel width in the printing direction and the partition wall width in the printing direction, as shown in FIG. 5B, the plate and the pixel are completely aligned at the center as shown in FIG. Needless to say, as shown in (b), even when the plate is shifted to the edge of one of the adjacent pixels, the ink does not flow into the adjacent pixels, so that the alignment tolerance is widened and alignment is easy. Become.

  Next, a method for forming the organic light emitting medium layer will be described in detail. In the following description, the case where the above-described method for forming an organic light-emitting medium layer is applied to a light-emitting layer is shown, but any organic light-emitting medium layer such as a hole transport layer or an electron transport layer can be used. .

  First, a hole transport layer is formed using the TFT substrate 1 shown in FIG. As the hole transport material for forming the hole transport layer, polyaniline derivatives, polythiophene derivatives, polyvinylcarbazole (PVK) derivatives, poly (3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS) are used. A mixture (PEDOT / PSS) is mentioned. These materials can be dissolved or dispersed in a solvent to form a hole transport material ink, and can be applied to the entire surface by spin coating to form a thin film.

After forming the hole transport layer, an organic light emitting layer is formed.
Organic light-emitting materials forming the organic light-emitting layer are, for example, coumarin-based, perylene-based, pyran-based, anthrone-based, porphyrene-based, quinacridin-based, N, N′-dialkyl-substituted quinacdolin-based, naphthalimide-based, N, N′-diaryl. Dispersed luminescent dyes such as substituted pyrrolopyrrole and iridium complexes in polymers such as polystyrene, polymethylmethacrylate, and polyvinylcarbazole, and polyarylene, polyarylene vinylene, and polyolefin polymer materials Is mentioned. These organic light emitting materials can be dissolved or dispersed in a solvent to obtain an organic light emitting ink. Examples of the solvent for dissolving or dispersing the organic light emitting material include toluene, xylene, acetone, anisole, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, or a mixed solvent thereof. Among them, aromatic organic solvents such as toluene, xylene, and anisole are preferable from the viewpoint of the solubility of the organic light emitting material.

  The organic light-emitting layer can be formed by a relief printing method using a water development type resin relief (letter plate). Examples of the water-developable photosensitive resin constituting the resin plate in the present invention include a type having a hydrophilic polymer and a monomer containing an unsaturated bond, a so-called crosslinkable monomer and a photopolymerization initiator as constituent elements. In this type, polyamide, polyvinyl alcohol, cellulose derivatives and the like are used as hydrophilic polymers. Examples of the crosslinkable monomer include methacrylates having a vinyl bond, and examples of the photopolymerization initiator include aromatic carbonyl compounds. Of these, a polyamide-based water-developable photosensitive resin is preferable from the viewpoint of printing suitability.

  The base material used for the resin relief printing plate is formed of a material different from the synthetic resin material forming the projections. As a substrate, it is sufficient to have mechanical strength for printing, and polyethylene, polystyrene, polybutadiene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyamide, polyethersulfone, polyethylene terephthalate, polyethylene naphthalate, polyethersulfone. A known synthetic resin such as polyvinyl alcohol, a known metal such as iron, copper, or aluminum, or a laminate thereof can be used. In addition, as a base material which comprises the resin relief printing plate used for this invention, it is requested | required that it should have sufficient rigidity to suppress the dimensional change of a resin part, and that a base material itself cannot change a dimension easily. Moreover, the thing with high tolerance with respect to the organic solvent contained in organic luminescent ink is desirable. Therefore, a metal material is preferably used as the material used as the substrate. Among the base materials made of metal, a steel base material and an aluminum base material are preferable from the viewpoint of processability and economy.

  In addition, dimensional changes due to temperature changes can be considered as a factor causing dimensional changes in resin plates. However, if the substrate itself is less likely to cause dimensional changes due to temperature, it is also possible to suppress dimensional changes as plates. Therefore, it is desirable that the base material used has a small thermal expansion coefficient. The thermal expansion coefficient of the material used for the substrate is preferably 2.0 × 10 −5 / K or less, and more preferably 3.0 × 10 −6 / K or less. A metal such as iron exhibits a sufficiently low thermal expansion coefficient as compared with a polyester film having a thermal expansion coefficient of 1.0 × 10 −4 / K or more, and from this point, it is also suitable as the substrate 200 of the resin plate of the present invention. Incidentally, the thermal expansion coefficient of iron is 1.2 × 10 −5 / K. Furthermore, iron and nickel alloys exhibit a lower coefficient of thermal expansion than iron. Among them, alloys having a ratio of 64% iron and 36% nickel have a coefficient of thermal expansion less than one-tenth that of iron and general metals. The most preferred alloy shown.

  As the solvent used in the organic light emitting ink, an aromatic organic solvent is preferably used. The solubility parameter (hereinafter referred to as SP value) of toluene representing an aromatic organic solvent is 8.9, and the SP value of xylene is 8.8. In contrast, the SP value of polyamide (nylon) which is a water-soluble resin material is 13.6, the SP value of polyvinyl alcohol is 12.6, the SP value of cellulose is 15.7, and the SP values of toluene and xylene are It is clear that these water-soluble resins are sufficiently resistant to aromatic organic solvents such as toluene and xylene because they are sufficiently separated.

  Further, it is desirable to use a photosensitive resin as the resin material because it is easy to process. For example, the photosensitive resin which has a polymer and the monomer containing an unsaturated bond, and a photoinitiator as a component is mentioned. At this time, as the polymer, it is preferable that the polymer is water-soluble for the same reason as described above, and polyamide, polyvinyl alcohol, cellulose derivative, and acrylic resin can be used. Further, as the monomer containing an unsaturated bond, for example, methacrylates having a vinyl bond can be used, and as the photopolymerization initiator, for example, an aromatic carbonyl compound can be used.

  In addition to the photolithography method, the convex portion can be formed by laser ablation or cutting as a method for forming the convex portion in the resin relief printing plate of the present invention.

  The printing machine used for forming the organic light emitting layer can be any letterpress printing machine that prints on a flat plate, but a printing machine as shown below is desirable. The letterpress printing machine has a plate cylinder on which an ink tank, an ink chamber, an anilox roll, and a resin letterpress are attached. The ink tank contains organic luminescent ink diluted with a solvent, and the organic luminescent ink is fed into the ink chamber from the ink tank. The anilox roll rotates in contact with the ink supply part of the ink chamber and the plate cylinder.

  As the anilox roll rotates, the organic light-emitting ink supplied from the ink chamber is uniformly held on the surface of the anilox roll, and then transferred to the convex portion of the resin relief plate attached to the plate cylinder with a uniform film thickness. Furthermore, the substrate to be printed (TFT substrate 1) is fixed on a slidable substrate fixing base and moved to the printing start position while adjusting the position by the pattern adjustment mechanism of the convex pattern of the resin relief plate and the pattern of the substrate to be printed. Then, in accordance with the rotation of the plate cylinder, the convex portion of the resin relief printing plate further moves while being in contact with the substrate to be printed, and the organic light emitting ink is transferred by patterning to a predetermined position on the substrate to be printed on the stage.

  At that time, by printing in a state in which the rolling direction of the plate cylinder and the stripe direction of the plate, and the long side direction of the pixel are parallel, the time and distance of contact with the pixel are maintained in the traveling direction to some extent. This enables the uniformity of the film thickness within the pixel and the uniformity of the entire pattern surface.

As shown in FIG. 1, after forming the organic light emitting layer (red (R) organic light emitting layer 41, green (G) organic light emitting layer 42, blue (B) organic light emitting layer 43), the cathode layer (second electrode 5). Form.
As a material for the cathode layer (second electrode 5), a material according to the light emitting characteristics of the organic light emitting layer can be used. For example, simple metals such as lithium, magnesium, calcium, ytterbium, aluminum, and these, gold, silver, etc. Examples include alloys with stable metals. Alternatively, a conductive oxide such as indium, zinc, or tin can be used. Examples of the method for forming the cathode layer (second electrode 5) include a method for forming by a vacuum vapor deposition method using a mask. Finally, in order to protect these organic EL constituents from external oxygen and moisture, a glass cap 8 and an adhesive 9 are hermetically sealed to obtain an organic EL display panel.

Next, examples of the present invention will be described.
In this embodiment, the pixel electrode (first electrode 2), the extraction electrode, an insulating layer made of SiNx film for protecting the TFT circuit, and an insulating layer made of polyimide are already provided. Using a TFT substrate 1 that is formed so as to partition, and thus also functions as a partition wall 7 of each pixel, a hole transport layer 3, a light emitting layer, and a cathode (second electrode 5) are sequentially formed thereon. Thus, an active matrix type organic EL display panel was prepared.

  At this time, the bottom surface of the pixel opening P1 partitioned by the partition walls 7 was a rectangular shape with a = 30 μm and b = 120 μm. That is, the ratio of the long side to the short side of the pixel was 0.4.

The hole transport layer 3 was formed by applying a PEDOT / PSS aqueous dispersion on the TFT substrate 1 by spin coating to obtain a thin film having a thickness of 50 nm. The light emitting layer is an organic light emitting material made of polyfluorene-based R material, G material, and B material dissolved in toluene so as to have a concentration of 1%. R, G, and B were separately applied to each pixel and printed by the relief printing method. At this time, a water-developing type photosensitive resin plate was used for printing of the light emitting layer. The contact angle of the luminescent material ink with respect to the plate surface was 10 degrees or less.
The plate cylinder around which the relief plate was wound was rolled in the stripe direction of the stripe-like relief image forming portion and printed parallel to the long side of the pixel, and the convex portion of the stripe was transferred to the center of the pixel shape.

A cathode layer (second electrode 5) made of Ca and Al was formed thereon by vacuum vapor deposition using a resistance heating vapor deposition method. Finally, in order to protect these organic EL constituents from external oxygen and moisture, they were hermetically sealed using a glass cap 8 and an adhesive 9 to produce an organic EL display element panel.

At the peripheral part of the display part of the obtained panel, there are anode-side and cathode-side extraction electrodes connected to each pixel electrode, and the panel lighting display is made by connecting to the driving device through these drivers Confirmation was performed to check the light emission state. The film thickness within the pixel was good and the panel was lit evenly.

(Comparative Example 1)
The operation method is the same as in practical example 1, but when the pixel width of the TFT substrate is 120 μm for a and 30 μm for b. a / b = 4 As shown in FIG.

(Comparative Example 2)
The operating method is the same as in Example 1, but the partition of the TFT substrate is 50 μm.

<Comparison result>
Comparative example 1 The convex part of the plate was not in contact with the substrate, and there were places where transfer was impossible. The panel lighting was uneven.
Comparative Example 2 A transfer failure due to the plate not touching the substrate on the partition wall. The panel lighting was uneven.

It is an explanatory sectional view of an organic EL display panel. 2 is an explanatory sectional view of a TFT substrate 1. FIG. It is a stripe arrangement explanatory drawing of a pixel, a short side and a long side are indicated by a and b, respectively, a partition wall around the pixel, and (a) the printing direction of Example 1 and (b) Comparative Example 1. It is explanatory drawing explaining the printing process in this invention. It is explanatory drawing which shows the relationship between the line width of a letterpress in this invention, and a pixel width.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... TFT substrate, 2 ... Cathode, 3 ... Hole transport layer, 5 ... Anode, 7 ... Partition, 14a ... Organic luminescent ink, 41 ... Red organic luminescent layer, 42 ... Green organic luminescent layer, 43 ... Blue organic luminescent layer

Claims (5)

A method of manufacturing an organic electroluminescent element in which an organic light emitting medium layer is formed in an opening of a partition wall,
The pixel region of the substrate, in which the periphery of the pixel is surrounded by a partition on a lattice, is a rectangle having a long side and a short side, and at least one organic light emitting medium layer is rotated by rotating a plate cylinder on which a relief plate is disposed. A method for producing an organic electroluminescent element, comprising sequentially printing in the long side direction.   2. The method of manufacturing an electroluminescent element according to claim 1, wherein the relief plate has a striped surface pattern parallel to the long side direction.   The length of the short side of the pixel region is a, and the width of the partition wall in the short side direction is c, and the line width x of the relief plate satisfies a <x <a + c. Manufacturing method of electroluminescent element.   The method of manufacturing an organic electroluminescent element according to any one of claims 1 to 3, wherein a height of the partition wall perpendicular to the printing direction of the substrate is 0.5 to 5 µm.   A method for producing an organic EL display panel, wherein the resolution of a display using the organic electroluminescent element according to claim 1 is in a range of 50 ppi to 400 ppi.