JP2007253447A - Relief printing plate for printing and printed matter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a relief printing plate for a highly precise printing capable of forming an ink pattern requiring an extremely high printing accuracy represented by a case where an organic light emitting layer in an organic EL element is formed by using an organic light emitting ink by a relief printing process. <P>SOLUTION: In the relief printing plate 104 for printing in which an ink 108 is fed on a projecting part pattern of the relief printing plate 104, the ink 108 on the projecting part pattern is transferred on a body 106 to be printed, and an ink pattern 108a is formed on the surface of the body 106 to be printed, the relief printing plate for the highly precise printing is characterized in that a mean roughness Rz of ten points on the surface of the projecting part pattern of the relief printing plate 104 for printing is ≤25% of the length of the shortest side of the projecting part pattern. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a printing relief plate used in a relief printing method, and a printed matter produced using the printing relief plate. As this printed matter, an organic electroluminescence element (hereinafter referred to as an organic EL element) can be exemplified, and at least one layer of organic EL layers such as an organic light emitting layer of the organic EL element can be formed by a relief printing method. Moreover, as said printed matter, a color filter, a circuit base material, a thin-film transistor, a microlens, a biochip etc. other than an organic EL element can be illustrated as printed matter.

  An organic electroluminescence element (hereinafter referred to as an organic EL element) is an element in which an organic light emitting layer made of an organic light emitting material is formed between two opposing electrodes, and light is emitted by passing a current through the organic light emitting layer. In order to emit light efficiently, the thickness of the light emitting layer is important, and it is necessary to form a thin film of about 100 nm. Further, in order to make this a display, it is necessary to pattern it with high definition.

  Organic light-emitting materials include low-molecular materials and high-molecular materials. In general, low-molecular materials are formed into thin films by resistance heating vapor deposition or the like, and then patterned using a fine pattern mask. There is a problem that the patterning accuracy is less likely to increase as the size increases.

  Therefore, recently, a method of using a polymer material as an organic light emitting material, dissolving the organic light emitting material in a solvent to form a coating liquid, and forming a thin film by a wet coating method has been tried. As the wet coating method for forming a thin film, there are a spin coating method, a bar coating method, a protruding coating method, a dip coating method, and the like. However, it is considered difficult to form a thin film by a printing method that is good at coating patterning.

Furthermore, among various printing methods, organic EL elements and displays often use a glass substrate as a substrate, and therefore methods such as gravure printing that use hard plates such as metal printing plates are unsuitable and elastic. An offset printing method using a rubber plate having a stencil and a relief printing method using a photosensitive resin plate mainly composed of rubber or other resin are appropriate. Actually, as a trial of these printing methods, a method by offset printing (Patent Document 1), a method by letterpress printing (Patent Document 2) and the like have been proposed.
JP 2001-93668 A JP 2001-155858 A

  In the case of a large display for television use, the pattern of the organic light emitting layer in the organic EL element has a line width of 100 μm and a pixel pitch of 500 μm, for example, in a wide display with a diagonal of 40 inches. In the case of a small display such as a mobile phone, for example, in a mainstream QVGA (320 × 240 pixels) with a diagonal size of 2 inches, the width of one corner subpixel is 40 μm and the pixel pitch is 120 μm. When a high-definition display is to be formed by a relief printing method using an organic light-emitting ink in which an organic light-emitting material is dissolved or dispersed in a solvent, a very high printing accuracy of ± 5 μm is required. At this time, when the pattern accuracy of the formed organic light emitting layer is poor, a short circuit due to direct contact with the electrode transport layer such as the electrode layer or the hole transport layer or the electron transport layer, or an organic light emitting layer having a different light emission color. Color mixing will occur.

  Moreover, the film thickness of the organic light emitting layer to be formed is a very thin layer of about 50 to 150 nm. The formed organic light emitting layer is required to have a uniform film thickness and high smoothness. If the thickness of the formed organic light emitting layer is not uniform, current will not flow easily at the thick part, and current leakage will occur at the thin part, resulting in uneven light emission. Uneven light emission occurs.

  Therefore, in the present invention, it is possible to form an ink pattern that requires a very high printing accuracy, as typified by forming an organic light emitting layer in an organic EL element by a relief printing method using an organic light emitting ink. An object is to provide a relief printing plate for high-definition printing.

  The present inventors have found that the surface roughness of a printing relief plate used for relief printing is greatly related to obtaining a highly accurate printing pattern in the ink pattern obtained by the relief printing method.

  Accordingly, the invention according to claim 1 is for printing used when supplying ink to a convex pattern of a relief plate, transferring the ink in the convex pattern to the printing medium, and forming an ink pattern on the surface of the printing medium. In the relief plate, a ten-point average roughness Rz of the convex pattern surface of the printing relief plate is 25% or less of the length of the shortest side of the convex pattern.

  The invention according to claim 2 is the printing relief plate according to claim 1, wherein the convex pattern of the printing relief plate is made of a resin.

  The invention according to claim 3 is the method for producing a printing relief plate according to claim 1 or 2, wherein the convex pattern of the printing relief plate contains a water-soluble polymer.

  According to a fourth aspect of the present invention, a plate material having a photosensitive resin layer provided on a substrate is used, and the plate material is exposed by using a photomask, and the exposed plate material is developed to develop the projection. 4. A method for producing a relief printing plate according to claim 1, wherein a part pattern is formed.

  The invention according to claim 5 is the step of supplying ink from the ink supply to the convex pattern of the printing relief plate according to any one of claims 1 to 3, and the convex pattern of the printing relief plate It was set as the manufacturing method of the printed matter characterized by having the process of transferring ink to the to-be-printed body surface, and forming an ink pattern in the to-be-printed body surface.

  The invention according to claim 6 comprises an organic EL layer including at least a first electrode, a second electrode, and an organic light emitting layer, and causes the organic light emitting layer to emit light by passing a current from both electrodes to the organic light emitting layer. In the luminescence element, a step of supplying an ink obtained by dissolving or dispersing an organic EL layer forming material in a solvent to the convex pattern of the printing relief plate according to any one of claims 1 to 3, and a convexity of the printing relief plate A method for producing an organic EL device comprising the steps of: transferring the ink in a partial pattern onto a surface of a substrate to be printed, and forming at least one layer of the organic EL layer on the surface of the substrate to be printed.

  The invention according to claim 7 comprises an organic EL layer comprising at least a first electrode, a second electrode, and an organic light emitting layer, and causing the organic light emitting layer to emit light by passing a current from both electrodes to the organic light emitting layer. A step of supplying an organic light emitting ink obtained by dissolving or dispersing an organic light emitting material in a solvent to the convex pattern of the printing relief plate according to any one of claims 1 to 3, and a convexity of the printing relief plate An organic electroluminescent element manufacturing method comprising a step of transferring an organic light emitting ink in a partial pattern onto a surface of a substrate to be printed and forming an organic light emitting layer on the surface of the substrate to be printed.

  The printing relief plate used for printing by a general relief printing method has a good inking amount when the surface roughness is rough in order to obtain a sufficient inking amount on the relief plate surface. Is said to be high. However, for example, in the case of an organic EL layer including an organic light emitting layer in an organic EL element, the thickness of the layer to be formed is on the order of submicrons, and a printing relief plate made of a convex pattern having a smooth surface is used. However, there is no shortage of inking.

  In the present invention, the ten-point average roughness Rz of the convex pattern surface of the relief printing plate is 25% or less of the length of the shortest side of the convex pattern. It was possible to form a uniform ink pattern with respect to the planar shape, and a high-definition printed matter could be obtained.

  In addition, by using a resin for the convex pattern of the printing relief plate, it has become possible to obtain a printed matter having a good ink pattern without damaging the substrate to be printed even on a hard substrate such as a glass substrate. .

  In addition, since the convex pattern of the printing relief plate contains a water-soluble polymer, the water-soluble polymer is highly resistant to organic solvents, so that the plate is less likely to swell or deform when an organic solvent is used in the ink. Therefore, it became possible to obtain high-definition printed matter.

  Further, in a printing relief plate, a printing relief plate having a high-definition projection pattern can be obtained by using a printing plate having a photosensitive resin layer on a substrate and forming a projection pattern by a photolithography method. did it.

  In addition, by forming an ink pattern on a substrate to be printed by a relief printing method using these relief printing plates of the present invention, it has become possible to produce an inexpensive and high-definition printed matter.

  Moreover, it became possible to manufacture a high-definition organic EL element at low cost by forming at least one of the organic EL layers of the organic EL element using the printing relief plate of the present invention.

  In addition, among organic EL layers, by forming an organic light emitting layer that needs to be applied to RGB three colors, it has become possible to manufacture a high-definition organic EL element at low cost.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to this.

  FIG. 1 shows an explanatory sectional view of an example of the relief printing plate of the present invention. A convex pattern 201 is formed on the substrate 200 in both FIG. In FIG.1 (b), the convex part pattern is formed on the base material independently with respect to the adjacent convex part pattern. In the present invention, any of the printing relief plates shown in FIGS. 1A and 1B may be used. However, as shown in FIG. It is preferable to use a letterpress. In a printing relief plate, a resin is suitably used for the convex pattern, but by forming the pattern independently, deformation of the resin used for the convex pattern due to the solvent or heat of the ink can be suppressed. In particular, when a metal material instead of a resin material is used as the base material, the deformation of the plate can be suppressed during printing, which can be suitably used.

  The relief printing plate of the present invention is characterized in that the ten-point average roughness Rz of the convex pattern surface is 25% or less of the length of the shortest side of the convex pattern. FIG. 2 shows an explanatory schematic diagram of the convex pattern and the shortest side in the printing relief plate of the present invention. The shortest side L is the width of the stripe if the convex pattern 222 is striped (FIG. 2A), and the shortest side L is the length of the short side if the convex pattern 222 is rectangular (FIG. 2). 2 (b)), if the convex pattern 222 is a circle, the shortest side L is the length of the diameter, and if the convex pattern 222 is an ellipse, the shortest side L is the short axis length L (FIG. 2). (C)).

  In the present invention, by setting the ten-point average roughness Rz of the convex pattern surface to 25% or less of the length of the shortest side of the convex pattern, the resulting ink pattern has a uniform film thickness, and the pattern shape is also It will be good. The relief printing plate having a smooth surface shape of the present invention requires that the formed layer has a very thin film thickness of 50 to 150 nm, and that the formed layer has a uniform film thickness. It can be suitably used for forming an organic EL layer in an organic EL element.

  The ten-point average roughness Rz on the convex pattern surface can be measured with an apparatus such as an atomic force microscope (AFM), a contact surface shape measuring device, or a non-contact surface shape measuring device.

  For the relief printing plate of the present invention, a plate material in which a resin layer is provided on a substrate can be suitably used. By using such a plate material and making the convex part pattern made of resin, an ink pattern can be formed on a hard printed material such as a glass substrate without damaging the printed material.

  In the plate material used for the relief printing plate of the present invention, the substrate on which the projection pattern is formed is only required to have mechanical strength against printing, such as polyethylene, polystyrene, polybutadiene, polyvinyl chloride, polyvinylidene chloride, Known synthetic resins such as polyvinyl acetate, polyamide, polyethersulfone, polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, and polyvinyl alcohol, known metals such as iron, copper, and aluminum, or laminates thereof can be used. .

  In addition, as a base material which comprises the 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 solvent contained in ink is desirable. Therefore, a metal is preferably used as the material used as the substrate. Moreover, among the base materials made of a metal material, a steel base material or an aluminum base material can be suitably used in terms of workability and economy.

  In the plate material used for the printing relief plate of the present invention, the resin layer provided on the substrate is nitrile rubber, silicone rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprene rubber, butyl rubber, acrylonitrile rubber, ethylene propylene rubber. In addition to rubber such as urethane rubber, polyethylene, polystyrene, polybutadiene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyamide, polyurethane, polyethersulfone, polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyvinyl alcohol, etc. One or more types can be selected from these synthetic resins, copolymers thereof, natural polymers such as cellulose, and the like.

  When manufacturing an organic EL element, when printing using an organic light-emitting ink in which an organic light-emitting material is dissolved or dispersed in a solvent, fluorine elastomer or polytetrafluoroethylene is used from the viewpoint of solvent resistance to the organic solvent. Water-soluble solvents such as fluorinated resins such as polyvinylidene fluoride, poly (vinylidene fluoride) and copolymers thereof, polyamides, polyvinyl alcohol, cellulose acetate succinate, partially saponified polyvinyl acetate, and cationic piperazine-containing polyamides It is desirable to use a polymer that is soluble in water. In particular, since aromatic organic solvents such as toluene and xylene are used as solvents for organic light-emitting inks, they exhibit high solvent resistance to aromatic organic solvents and are highly hydrophilic and soluble in water-soluble solvents. Can be suitably used.

  In addition, it is desirable to use a photosensitive resin as the resin layer used in the plate material because a high-definition convex pattern can be easily processed. For example, a monomer containing a polymer and an unsaturated bond and a photopolymerization initiator are formed. A photosensitive resin as an element can be mentioned. At this time, the polymer can be appropriately selected from the resin materials shown above. In addition, as the polymer, a water-soluble polymer can be suitably used in the same manner as described above in that it has high resistance to an organic solvent. In the case where a water-soluble polymer is used, water is used as a developer in a development step described later. 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 the case where a convex pattern is formed by photolithography using a photosensitive resin, a method for producing a relief printing plate of the present invention will be described. FIG. 3 shows an explanatory cross-sectional view of a method for producing a printing relief plate. First, as shown in FIG. 3A, a plate material in which a photosensitive resin is formed on one surface on a base material 200 is prepared. Next, as shown in FIG. 3B, a photomask 206 having a light shielding portion 205 and a light transmitting portion and having a pattern formed by the light transmitting portion is disposed on the photosensitive resin. The photomask has a structure in which a light shielding portion 205 made of, for example, a chrome thin film is patterned on a light-transmitting glass 104, and the light shielding portion 205 and the chrome thin film are formed at a portion where the chromium thin film is formed. The part where there is no light becomes the translucent part.

  Next, as shown in FIG. 3C, exposure is performed by irradiating an active energy ray 207 typified by ultraviolet light through the photomask. At this time, the portion irradiated with the active energy ray through the light transmitting portion of the photomask is cured.

  Next, the photomask is removed from the resin relief printing and development is performed. The uncured portion that is not irradiated with light by exposure is removed by development, and the resin relief printing plate of the present invention as shown in FIG. At this time, when using a water-developing type resin relief plate in which the uncured portion can be dissolved and removed with water, water is used as the developer. Further, after the development, baking or post-exposure may be performed for the purpose of further curing the resin layer. In addition to the exposure method using a photomask, a light-impermeable layer such as carbon or aluminum is formed on the surface of the photosensitive resin layer, and this is ablated by a laser to form the light-shielding portion 205, followed by exposure. It is also possible to do.

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

  Next, the manufacturing method of the printed matter which forms an ink pattern on the to-be-printed substrate surface by a relief printing method using the relief printing plate of this invention is shown. FIG. 4 shows a schematic diagram of a relief printing apparatus used for producing the printed material of the present invention. The printing substrate 106 is fixed to the stage 107, the printing relief plate 104 is fixed to the plate cylinder 105, the printing relief plate 104 is in contact with the anilox roll 103 which is an ink supply body, and the anilox roll 103 is replenished with ink. A device 101 and a doctor 102 are provided.

  First, ink is replenished from the ink replenishing device 101 to the anilox roll 103, and excess ink out of the ink 108 supplied to the anilox roll 103 is removed by the doctor 102. The ink replenishing device 101 may be a dripping type ink replenishing device, a fountain roll, a slit coater, a die coater, a cap coater such as a cap coater, or a combination thereof. For the doctor 102, a known object such as a doctor roll can be used in addition to the doctor blade. Further, the anilox roll 103 can be made of chromium or ceramics. Further, instead of the cylindrical anilox roll, it is also possible to use a flat anilox plate as the ink supply to the printing relief plate. The flat anilox plate is disposed, for example, at the position of the printing substrate 106 in FIG. 4. After the ink is replenished to the entire surface of the anilox plate by an ink replenishing device, the ink is supplied to the printing substrate by rotating the plate cylinder. Can be done.

  The ink uniformly held by the doctor on the surface of the anilox roll 103 which is an ink supply body to the printing relief plate is transferred and supplied to the projection pattern of the printing relief plate 104 attached to the plate cylinder 105. Then, as the plate cylinder 105 rotates, the convex pattern of the printing relief plate 104 and the substrate move relatively while in contact with each other, and the ink 108 is transferred to a predetermined position on the printing substrate 106 on the stage 107 to be printed substrate. An ink pattern 108a is formed on the substrate. After the ink pattern is provided on the substrate to be printed, a drying step using an oven or the like can be provided as necessary.

  Note that when printing the ink on the printing relief plate on the printing substrate, the stage 17 to which the printing substrate 106 is fixed may be moved in accordance with the rotation of the plate cylinder 105. FIG. A printing unit including the upper plate cylinder 105, the printing relief plate 104, the anilox roll 103, and the ink replenishing device 101 may be moved in accordance with the rotation of the plate cylinder. In the printing relief plate of the present invention, a resin layer may be formed on the plate cylinder 15 and directly plate-making to form a projection pattern.

  FIG. 4 shows a sheet-fed relief printing apparatus that forms an ink pattern on the substrate to be printed one by one. However, in the method for producing a printed material according to the present invention, the substrate to be printed can be wound in a web shape. In some cases, a roll-to-roll relief printing apparatus can be used. When a roll-to-roll type letterpress printing apparatus is used, it is possible to continuously form an ink pattern and to reduce the manufacturing cost.

  Next, a method for manufacturing an organic EL element will be described as an example of a method for manufacturing a printed matter using the high-definition resin relief plate in the present invention. The present invention is not limited to this. FIG. 5 shows an explanatory cross-sectional view of the organic EL element of the present invention. There are a passive matrix type and an active matrix type as a driving method of the organic EL element, but the organic EL element of the present invention can be applied to either a passive matrix type organic EL element or an active matrix type organic EL element. .

  The passive matrix method is a method in which stripe-shaped electrodes are opposed to each other so as to be orthogonal to each other, and light is emitted at the intersection, whereas the active matrix method uses a so-called thin film transistor (TFT) substrate in which a transistor is formed for each pixel. Thus, the light is emitted independently for each pixel.

  As shown in FIG. 5, the organic EL element of the present invention has a first electrode 2 in a stripe shape as an anode on a substrate 1. The partition wall is provided between the first electrodes, and preferably covers the first electrode end portion for the purpose of preventing a short circuit due to burrs or the like at the first electrode end portion.

  And the organic EL element of this invention has the organic EL layer which consists of an organic light emitting layer and a light emission auxiliary layer in the area | region (light emission area | region L, pixel part) on the 1st electrode 2 and divided by the partition 7. ing. The organic EL 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, an electron injection layer, and a charge generation layer. In FIG. 5, 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.

  Next, the 2nd electrode 5 is arrange | positioned as a cathode so as to oppose the 1st electrode 2 which is an anode on an organic luminescent medium layer. In the case of the passive matrix method, the second electrode is provided in a stripe shape so as to be orthogonal to the first electrode having a stripe shape. In the case of the active matrix method, the second electrode is formed on the entire surface of the organic EL element. Further, although not shown, a sealing body such as a glass cap is provided on the entire effective pixel in order to prevent moisture and oxygen in the environment from entering the first electrode, the organic light emitting layer, the light emitting auxiliary layer, and the second electrode. It is provided and bonded to the substrate via an adhesive.

  The organic EL device of the present invention includes at least a substrate, a patterned first electrode supported by the substrate, an organic light emitting layer, and a second electrode. The organic EL element of the present invention may have a structure in which the first electrode is a cathode and the second electrode is an anode, contrary to FIG. In addition, in order to protect the organic light emitting medium layer and the electrode from the ingress of external oxygen and moisture in place of a sealing body such as a glass cap, a sealing layer having a function of a passivation layer and a protective layer for protecting from external stress, or both, is provided. You may provide a stop base material.

  Next, the manufacturing method of an organic EL element is demonstrated.

  As the substrate according to the present invention, any substrate can be used as long as it has an insulating property. In the case of a bottom emission type organic EL element that extracts light from the substrate side, it is necessary to use a transparent substrate.

  For example, a glass substrate or a quartz substrate can be used as the substrate. Further, it may be a plastic film or sheet such as polypropylene, polyethersulfone, polycarbonate, cycloolefin polymer, polyacrylate, polyamide, polymethyl methacrylate, polyethylene terephthalate, or 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 these as a board | substrate.

  In addition, it is more preferable to reduce the moisture adsorbed on the inside or the surface of the substrate as much as possible by performing a heat treatment on these substrates in advance. Further, in order to improve the adhesion depending on the material to be laminated on the substrate, it is preferable to use after performing surface treatment such as ultrasonic cleaning treatment, corona discharge treatment, plasma treatment, UV ozone treatment.

  Further, a thin film transistor (TFT) can be formed on these to form a substrate for an active matrix organic EL element. FIG. 6 shows an explanatory cross-sectional view of an example of the active matrix substrate of the present invention. In the case of the organic EL element substrate of the present invention, the planarization layer 117 is formed on the TFT 120, and the lower electrode (first electrode 2) of the organic EL element is provided on the planarization layer 117. In addition, the TFT and the lower electrode are preferably electrically connected through a contact hole 118 provided in the planarization layer 117. By comprising in this way, the outstanding electrical insulation can be obtained between TFT and an organic EL element.

  The TFT 120 and the organic EL element formed above the TFT 120 are supported by a support 111. The support is preferably excellent in mechanical strength and dimensional stability. Specifically, the materials described above as the substrate can be used.

  As the TFT 120 provided on the support, a known thin film transistor can be used. Specifically, a thin film transistor mainly including an active layer in which a source / drain region and a channel region are formed, a gate insulating film, and a gate electrode can be given. The structure of the thin film transistor is not particularly limited, and examples thereof include a staggered type, an inverted staggered type, a top gate type, and a coplanar type.

The active layer 112 is not particularly limited, and examples thereof include amorphous semiconductor materials such as amorphous silicon, polycrystalline silicon, microcrystalline silicon, cadmium selenide, thiophene oligomers, poly (p-ferylene vinylene), and the like. It can be formed of an organic semiconductor material. These active layers are formed by, for example, depositing amorphous silicon by plasma CVD, ion doping, forming amorphous silicon by LPCVD using SiH ₄ gas, and crystallizing amorphous silicon by solid phase growth. After obtaining silicon, ion doping is performed by ion implantation, LPCVD using Si ₂ H ₆ gas, and amorphous silicon is formed by PECVD using SiH ₄ gas, and laser such as excimer laser is used. After annealing and crystallizing amorphous silicon to obtain polysilicon, polysilicon is deposited by ion doping (low temperature process), low pressure CVD or LPCVD, and thermally oxidized at 1000 ° C. or higher. Gate break Film is formed, an n + polysilicon gate electrode 114 is formed thereon, then, a method of ion doping (high temperature process), and the like by an ion implantation method.

As the gate insulating film 113, a film normally used as a gate insulating film can be used. For example, SiO ₂ formed by PECVD, LPCVD, etc., SiO obtained by thermally oxidizing a polysilicon film ₂ 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 display device of the present invention 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 116 of the transistor and the pixel electrode (first electrode 2) of the organic EL element are electrically connected. Connected. 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 element are connected through a connection wiring formed in a contact hole 118 that penetrates the planarizing 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, a contact hole 118 is 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 the 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.

  A first electrode 2 is provided on the substrate. When the first electrode is used as an anode, the material is a metal composite such as ITO (indium tin composite oxide), IZO (indium zinc composite oxide), tin oxide, zinc oxide, indium oxide, zinc aluminum composite oxide. A single layer or a stacked layer of metal materials such as oxide, gold, platinum, and chromium can be used. As a method for forming the first electrode, a dry film forming method such as a resistance heating vapor deposition method, an electron beam vapor deposition method, a reactive vapor deposition method, an ion plating method, or a sputtering method can be used.

  In addition, 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 the glass substrate by sputtering, and is patterned by photolithography to form the first electrode 2.

After the first electrode 2 is formed, the partition wall 7 is formed so as to cover the first electrode edge. The partition 7 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, and is a photo-curing resin of a photo radical polymerization system, a photo cation 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, 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. In the case of the spin coating method, the height of the partition wall can be controlled by conditions such as the number of rotations when spin coating, but there is a limit height in one coating, and if it is higher than that, multiple spin coatings are performed. Use an iterative approach.

  When the barrier rib is formed by a photolithography method using a photosensitive material, its shape can be controlled by exposure conditions and development conditions. For example, when a negative photosensitive resin is applied, exposed and developed, and then post-baked to obtain a partition wall, if the partition wall end portion has a forward taper shape, the development under this development condition is required. The type, concentration, temperature, or development time of the liquid may be controlled. If the development conditions are mild, the partition wall ends have a forward taper shape, and if the development conditions are severe, the partition wall ends have a reverse taper shape.

Further, when the partition wall forming material is SiO ₂ or 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 composed of an organic light emitting layer and a light emission auxiliary layer is formed. The organic EL layer sandwiched between the electrodes may be composed of an organic light emitting layer alone, an organic light emitting layer and a hole transport layer, a hole injection layer, an electron transport layer, an electron injection layer, a charge generation layer, etc. It is good also as a laminated structure with the light emission auxiliary layer for assisting light emission. The hole transport layer, hole injection layer, electron transport layer, electron injection layer, and charge generation layer are appropriately selected as necessary.

  In the present invention, at least one of the organic EL layers composed of a light emitting auxiliary layer such as an organic light emitting layer, a hole transport layer, a hole injection layer, an electron transport layer, an electron injection layer, and a charge generation layer is used as an organic EL layer material. Is formed by printing above the first electrode by a relief printing method using a resin relief plate having a projection pattern made of resin on a substrate and using a resin dissolved or dispersed in a solvent. Can be applied. Hereinafter, in the present invention, a case where an organic light emitting ink in which an organic light emitting material is dissolved or dispersed in a solvent is used will be described.

  The organic light emitting layer is a layer that emits light when an electric current is passed. Organic light-emitting materials formed by the organic light-emitting layer include 9,10-diarylanthracene derivatives, pyrene, coronene, perylene, rubrene, 1,1,4,4-tetraphenylbutadiene, tris (8-quinolato) aluminum complex, tris (4-methyl-8-quinolato) aluminum complex, bis (8-quinolato) zinc complex, tris (4-methyl-5-trifluoromethyl-8-quinolato) aluminum complex, tris (4-methyl-5-cyano-) 8-quinolate) aluminum complex, bis (2-methyl-5-trifluoromethyl-8-quinolinolate) [4- (4-cyanophenyl) phenolate] aluminum complex, bis (2-methyl-5-cyano-8-quinolinolate) [4- (4-cyanophenyl) phenolate] aluminum complex, Lis (8-quinolinolato) scandium complex, bis [8- (para-tosyl) aminoquinoline] zinc complex and cadmium complex, 1,2,3,4-tetraphenylcyclopentadiene, poly-2,5-diheptyloxy- A low molecular weight light emitting material such as para-phenylene vinylene can be used.

  Also, coumarin phosphors, perylene phosphors, pyran phosphors, anthrone phosphors, polyphyrin phosphors, quinacridone phosphors, N, N′-dialkyl-substituted quinacridone phosphors, naphthalimide phosphors, A material obtained by dispersing a low molecular weight light emitting material such as an N, N′-diaryl-substituted pyrrolopyrrole fluorescent material or a phosphorescent light emitting material such as an Ir complex in a polymer can be used. As the polymer, polystyrene, polymethyl methacrylate, polyvinyl carbazole and the like can be used.

  Further, poly (2-decyloxy-1,4-phenylene) (DO-PPP) and poly [2,5-bis- [2- (N, N, N-triethylammonium) ethoxy] -1,4-phenyl- PPP derivatives such as alto-1,4-phenylylene] dibromide, poly [2- (2′-ethylhexyloxy) -5-methoxy-1,4-phenylenevinylene] (MEH-PPV), poly [5-methoxy -(2-propanoxysulfonide) -1,4-phenylenevinylene] (MPS-PPV), poly [2,5-bis- (hexyloxy) -1,4-phenylene- (1-cyanovinylene)] ( CN-PPV), poly (9,9-dioctylfluorene) (PDAF), and polyspirofluorene may be used. Examples thereof include polymer precursors such as a PPV precursor and a PPP precursor. Other existing light emitting materials can also be used.

  Examples of the hole transport material forming the hole transport layer include metal phthalocyanines such as copper phthalocyanine and tetra (t-butyl) copper phthalocyanine, and metal-free phthalocyanines, quinacridone compounds, 1,1-bis (4-di-p -Tolylaminophenyl) cyclohexane, N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-biphenyl-4,4′-diamine, N, N′-di (1- Naphthyl) -N, N′-diphenyl-1,1′-biphenyl-4,4′-diamine and other aromatic amine-based low molecular hole injection transport materials, polyaniline, polythiophene, polyvinylcarbazole, poly (3,4 -Ethylenedioxythiophene) and polymer hole transport materials such as polystyrene sulfonic acid mixtures, thiophene oligomer materials, and other existing positive It can be selected from among transport material.

  Examples of the electron transport material for forming the electron transport layer include 2- (4-bifinylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (1 -Naphtyl) -1,3,4-oxadiazole, oxadiazole derivatives, bis (10-hydroxybenzo [h] quinolinolato) beryllium complexes, triazole compounds, and the like can be used.

  Solvents that dissolve or disperse the organic light emitting material include toluene, xylene, acetone, hexane, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, isopropyl alcohol, ethyl acetate, butyl acetate, 2-methyl- (t-butyl) Benzene, 1,2,3,4-tetramethylbenzene, pentylbenzene, 1,3,5-triethylbenzene, cyclohexylbenzene, 1,3,5-tri-isopropylbenzene and the like can be used alone or in combination. . Moreover, surfactant, antioxidant, a viscosity modifier, a ultraviolet absorber, etc. may be added to organic luminescent ink as needed.

  Examples of the solvent for dissolving or dispersing the hole transport material and the electron transport material include, for example, toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, isopropyl alcohol, ethyl acetate, butyl acetate, water and the like Alternatively, a mixed solvent thereof can be used. In particular, water or alcohols are suitable when forming a hole transport material into an ink.

  The organic light emitting layer and the light emission auxiliary layer are formed by a wet film forming method. Note that in the case where these layers have a laminated structure, it is not necessary to form all of the layers by a wet film formation method. As the wet film forming method, spin coating method, die coating method, dip coating method, discharge coating method, pre-coating method, roll coating method, bar coating method and the like, relief printing method, inkjet printing method, offset printing method, Examples of the printing method include a gravure printing method. In particular, when patterning organic light emitting layers of three colors of RGB, it can be selectively formed on the pixel portion by a printing method, and an organic EL element capable of color display can be manufactured. The film thickness of the organic light emitting medium layer is 1000 nm or less, preferably 50 nm to 150 nm, even when formed by a single layer or stacked layers.

  Again, the present invention is not only for forming an organic light emitting layer by a relief printing method using an organic light emitting ink, but also for a hole transport layer or an electron transport layer by a relief printing method using a hole transport ink or an electron transport ink. It can also be used when forming a light emission auxiliary layer.

  Next, a second electrode is formed. When the second electrode is a cathode, a material having high electron injection efficiency is used as the material. Specifically, a single metal such as Mg, Al, or Yb is used, or a compound such as Li, oxidized Li, or LiF is sandwiched by about 1 nm at the interface in contact with the light emitting medium, and Al or Cu having high stability and conductivity is laminated. And use. Or, in order to achieve both electron injection efficiency and stability, one or more metals such as Li, Mg, Ca, Sr, La, Ce, Er, Eu, Sc, Y, Yb, etc., which have low work function, and stable Ag, Al An alloy system with a metal element such as Cu is used. Specifically, alloys such as MgAg, AlLi, and CuLi can be used. Further, in the case of a top emission type organic EL device, the cathode needs to have transparency, and for example, transparency can be achieved by a combination of these metals and a transparent conductive layer such as ITO.

  As a method for forming the second electrode, a dry film formation method such as a resistance heating vapor deposition method, an electron beam vapor deposition method, a reactive vapor deposition method, an ion plating method, or a sputtering method can be used. Moreover, when it is necessary to make a 2nd electrode into a pattern, it can pattern by a mask etc. The thickness of the second electrode is preferably 10 nm to 1000 nm. 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 an organic light emitting layer between electrodes and letting an electric current flow. However, some of the organic light emitting material, the light emission auxiliary layer forming material, and the electrode forming material contain moisture in the atmosphere. Since it is easily deteriorated by oxygen, a sealing body is usually provided for shielding from the outside.

  For example, the sealing body includes a first electrode, an organic light emitting layer, a light emitting auxiliary layer, and a substrate on which the second electrode is formed. Then, sealing is performed by adhering the cap and the substrate with an adhesive around the peripheral portion so that the concave portion hits the second electrode.

  In addition, the sealing body is provided with a resin layer on a sealing material with respect to the substrate on which, for example, the first electrode, the organic light emitting layer, the light emission auxiliary layer, and the second electrode are formed. It is also possible to carry out by bonding the substrates.

At this time, the sealing material needs to be a base material having low moisture and oxygen permeability. Examples of the material include ceramics such as alumina, silicon nitride, and boron nitride, glass such as alkali-free glass and alkali glass, metal foil such as quartz, aluminum, and stainless steel, and moisture-resistant film. Examples of moisture-resistant films include films formed by CVD of SiOx on both sides of plastic substrates, films with low permeability and water-absorbing films, or polymer films coated with a water-absorbing agent. The water vapor transmission rate is preferably 10 ⁻⁶ g / m ² / day or less.

  Examples of the resin layer include photo-curing adhesive resins made of epoxy resins, acrylic resins, silicone resins, thermosetting adhesive resins, two-component curable adhesive resins, and ethylene ethyl acrylate (EEA) polymers. Examples thereof include acrylic resins, vinyl resins such as ethylene vinyl acetate (EVA), thermoplastic resins such as polyamide and synthetic rubber, and thermoplastic adhesive resins such as acid-modified products of polyethylene and polypropylene. Examples of methods for forming a resin layer on a sealing material include solvent solution method, extrusion lamination method, melting / hot melt method, calendar method, nozzle coating method, screen printing method, vacuum laminating method, hot roll laminating method, etc. Can be mentioned. A material having a hygroscopic property or an oxygen absorbing property may be contained as necessary. Although the thickness of the resin layer formed on a sealing material is arbitrarily determined by the magnitude | size and shape of the organic EL element to seal, about 5-500 micrometers is desirable.

  The substrate on which the first electrode, the organic light emitting layer, the light emission auxiliary layer, and the second electrode are formed and the sealing body are bonded together in a sealing chamber. When the sealing body has a two-layer structure of a sealing material and a resin layer, and a thermoplastic resin is used for the resin layer, it is preferable to perform only pressure bonding with a heated roll. When a thermosetting adhesive resin is used, it is preferable to perform heat curing at a curing temperature after pressure bonding with a heated roll. In the case where a photocurable adhesive resin is used, curing can be performed by further irradiating light after pressure bonding with a roll. Note that although the resin layer is formed over the sealing material here, the resin layer can be formed over the substrate and bonded to the sealing material.

  Before or instead of sealing with a sealing body, for example, as a passivation film, it is also possible to form a sealing body with an inorganic thin film, such as a silicon nitride film having a thickness of 150 nm using a CVD method. It is also possible to combine these.

Examples will be described below.
(Preparation of printed substrate)
An ITO film was formed on a 300 mm square glass substrate by sputtering, and the ITO film was patterned in a stripe shape by photolithography and etching with an acid solution. The line pattern of ITO as the anode was a pattern in which the line width was 100 μm, the space was 50 μm, and the line was formed with 192 lines. A 1.5 wt% aqueous solution of poly (3,4) ethylenedioxythiophene / polystyrene sulfonic acid (PEDOT / PSS) was formed to a thickness of 100 nm as a hole transport layer using a spin coater. 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 organic light emitting layer forming ink)
The following organic light-emitting inks comprising three colors of red, green, and blue (RGB) were prepared.
Red light emitting ink (R): 1% by weight toluene solution of polyfluorene derivative (Red light emitting material trade name Red1100 manufactured by Sumitomo Chemical Co., Ltd.)
Green light emitting ink (G): 1% by weight toluene solution of polyfluorene derivative (Green light emitting material, trade name Green 1300, manufactured by Sumitomo Chemical Co., Ltd.)
Blue luminescent ink (B): 1% by weight toluene solution of polyfluorene derivative (blue luminescent material, trade name Blue 1100 manufactured by Sumitomo Chemical Co., Ltd.)

(Preparation of printing letterpress)
A photosensitive resin material which is a base for letterpress by melt-coating a solvent-resistant photosensitive resin mainly composed of polyamide on the surface of a PET substrate having a thickness of 200 μm so that the total thickness becomes 1.4 mm. Formed. At that time, a PEN film having a 10-point average roughness Rz of 0.005 μm on the surface was laminated and solidified by cooling at room temperature. When the PEN film was peeled off after cooling, a plate material made of a plate-like photosensitive resin having a 10-point average roughness Rz of 0.005 μm on the surface could be formed. Thereafter, a negative film mask having a line width of 100 μm and a pitch of 350 μm was superimposed on this plate material, and a relief printing plate for printing was obtained through known exposure, development, drying, and post-exposure steps.

(Manufacture of organic EL elements)
The relief printing plate for high-definition printing was fixed to a cylinder of a sheet-fed printing press. Using this and the above-described organic light emitting ink, printing was performed for each color on the substrate to be printed. The organic light emitting layer was printed so that the red organic light emitting layer, the green organic light emitting layer, and the blue organic light emitting layer were arranged in a stripe pattern. After printing for each color, drying was performed in an oven at 130 ° C. for 1 hour. The film thickness of the formed pattern is 102 nm, the ten-point average roughness of the surface of the printed pattern is less than the detection lower limit of 0.005 μm, and the linearity of the printed pattern is calculated by the arithmetic average roughness. When measured, it was less than the detection lower limit of 0.007 μm. After drying, a 10 nm film of calcium was formed on the organic light emitting layer formed by printing, and then silver was vacuum deposited on the film by 300 nm, and finally sealed using a glass cap to produce the organic EL device of the present invention. . When the light emission characteristics of this organic EL element were observed, uniform light emission of 103 cd / m ² was obtained at 5 V over the entire surface in the pattern portion.

(Comparative example)
As a comparative example, a case where a relief printing plate having a smooth surface (conventional printing relief plate) is used will be described.

  A plate material (ten-point average roughness Rz on the surface is 7 μm) used for a relief printing plate for cardboard printing is overlaid with a negative film mask having a line width of 100 μm and a space of 350 μm, and is exposed by a known exposure and development process. Made a plate. The printing relief plate was fixed to a cylinder of a sheet-fed printing machine, printed on each color ink using the same substrate to be printed and organic light emitting ink as in the example, and then dried at 130 ° C. for 1 hour. . The thickness of the organic light-emitting layer pattern formed by printing was 152 nm, but the 10-point average roughness of the surface of the organic light-emitting layer pattern was 0.7 μm, and the linearity of the printed pattern was the arithmetic average roughness. As a result of measurement, it was 12 μm. After drying, in the same manner as in Example 1, calcium and silver were vacuum deposited on the formed organic light emitting layer to produce an organic EL device. When the light emission characteristics of the organic EL element were observed, nonuniform light emission due to nonuniform voltage application was observed.

  Note that the ten-point average roughness of the printing plate surface of the present invention, the ten-point average roughness of the surface of the organic light emitting layer pattern, and the arithmetic average roughness which is the linearity of the pattern of the organic light emitting layer are non-contact type. A surface shape measuring device (WYKO-NT8000, manufactured by Nihon Beco) was used. The measurement result which measured the shape of the plate material surface of an Example and a comparative example using the non-contact-type surface shape measuring apparatus in FIG. 7 was shown. FIG. 7A is a plan view (Rz = 0.005 μm) of the surface shape of the printing plate surface of the printing relief plate used in the examples, and FIG. 7B is the printing relief plate material used in the comparative example. It is a surface shape top view (Rz = 7 micrometer) of the surface.

FIG. 1 is an explanatory sectional view of an example of a relief printing plate according to the present invention. FIG. 2 is an explanatory schematic diagram of the convex pattern and the shortest side in the relief printing plate of the present invention. FIG. 3 is an explanatory sectional view of the method for producing a relief printing plate of the present invention. FIG. 4 is a schematic view of a relief printing apparatus used for producing the printed matter of the present invention. FIG. 5 is an explanatory cross-sectional view of the organic EL device of the present invention. FIG. 6 is an explanatory cross-sectional view of an example of an active matrix substrate. FIG. 7A is a plan view (Rz = 0.005 μm) of the surface shape of the printing plate surface of the printing relief plate used in the examples, and FIG. 7B is the printing relief plate material used in the comparative example. It is a surface shape top view (Rz = 7 micrometer) of the surface.

Explanation of symbols

200: base material 201: convex pattern 222: convex pattern L: shortest side 202a: photosensitive resin (uncured)
202b: convex pattern 204 made of photosensitive resin 204: glass 205: light shielding portion 206: photomask 207: active energy ray 11: ink replenishing device 12: doctor 13: anilox roll 14: letterpress for printing 15: plate cylinder 16: covered Print substrate 17: Stage 18: Ink 18a: Ink pattern 1: Substrate 2: First electrode 3: Hole transport layer 41: Red (R) organic light emitting layer 42: Green (G) Organic light emitting layer 43: Blue (B) Organic light emitting layer 5: second electrode 7: partition wall 8: glass cap 9: adhesive 111: support 112: active layer 113: gate insulating film 114: gate electrode 115: interlayer insulating film 116: drain electrode 117: planarization layer 118: Contact hole
119: Data line 120: TFT

Claims (7)

In the printing relief plate used when supplying the ink to the relief pattern of the relief plate, transferring the ink in the relief pattern to the printing material, and forming the ink pattern on the printing material surface,
The high-definition relief printing plate, wherein the ten-point average roughness Rz of the convex pattern surface of the relief printing plate is 25% or less of the length of the shortest side of the convexity pattern.   2. The relief printing plate according to claim 1, wherein the projection pattern of the relief printing plate is made of a resin.   The method for producing a printing relief plate according to claim 1 or 2, wherein the convex pattern of the printing relief plate contains a water-soluble polymer.   Using a plate material provided with a photosensitive resin layer on a substrate, exposing the plate material using a photomask, and developing the exposed plate material to form a convex pattern The manufacturing method of the relief printing plate in any one of Claims 1 thru | or 3.   Supplying the ink from the ink supply to the convex pattern of the printing relief plate according to any one of claims 1 to 3, and transferring the ink in the convex pattern of the printing relief plate to the surface of the printing medium; A method for producing a printed material, comprising a step of forming an ink pattern on the surface of the printing material. In an organic electroluminescence device comprising an organic EL layer including at least a first electrode, a second electrode, and an organic light emitting layer, and causing the organic light emitting layer to emit light by passing a current from both electrodes to the organic light emitting layer,
The step of supplying an ink obtained by dissolving or dispersing the organic EL layer forming material in a solvent to the convex pattern of the printing relief plate according to any one of claims 1 to 3, and the convex pattern of the printing relief plate A method for producing an organic EL device, comprising: transferring the ink to a surface of a substrate to be printed, and forming at least one layer of the organic EL layer on the surface of the substrate to be printed. In an organic electroluminescence device comprising an organic EL layer including at least a first electrode, a second electrode, and an organic light emitting layer, and causing the organic light emitting layer to emit light by passing a current from both electrodes to the organic light emitting layer,
A step of supplying an organic light emitting ink obtained by dissolving or dispersing an organic light emitting material in a solvent to the convex pattern of the printing relief plate according to any one of claims 1 to 3, and the convex pattern of the printing relief plate A method for producing an organic electroluminescence device, comprising: transferring an organic light emitting ink to a surface of a substrate to be printed, and forming an organic light emitting layer on the surface of the substrate to be printed.