JP6375615B2 - Letterpress for printing and method for producing printed matter - Google Patents

Description

  The present invention relates to a relief printing plate for producing a high-definition pattern by a printing method, and a method for producing a printed matter relating to printed electronics using the same to produce an electronic device or the like.

In general, printed electronics means that an electronic circuit, a sensor, an element, or the like is manufactured by utilizing a printing (printing) technique. Until now, it was said to be printable electronics from the viewpoint that “the printing method will be possible in the future”.
However, recently, it has come to be referred to as printed electronics from the viewpoint that “it is technically possible”.

Currently, in most semiconductors, displays, and electronic products, a fine pattern of an electronic circuit is produced (patterned) by using a photolithography technique. In silicon semiconductors, in order to increase price competitiveness, a method of forming a large number of semiconductor chips on a large-area silicon wafer is employed.
However, this method has limitations in the manufacture of inexpensive products, and in the manufacture of electronic products that aim to increase the area, it is difficult to reduce the manufacturing cost if the manufacturing method using photolithography technology is used. ing.
In printed electronics technology, the production of semiconductors and displays as well as electronic products by printing eliminates the need for exposure and etching used in normal semiconductor manufacturing processes. It is also attracting attention as a friendly manufacturing process.

  As an example of printed electronics, a method for manufacturing an organic EL element will be described below.

  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 electrodes, and light is emitted by passing a current through the organic light emitting layer. The film thickness 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 a 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, etc., but in order to pattern with high definition or to separate the RGB three colors, It is difficult to use these wet coating methods, and it is considered that thin film formation by a printing method that is good at coating patterning is most effective.

Furthermore, among various printing methods, organic EL elements and displays often use a glass substrate as a substrate, so a method using a hard plate such as a metal printing plate such as a gravure printing method is unsuitable, An offset printing method using an elastic rubber plate 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 (for example, see Patent Document 1), a method by letterpress printing (for example, see Patent Document 2), and the like have been proposed.

  In the case of a small display such as a mobile phone, the pattern of the organic light emitting layer in the organic EL element is, for example, 2 inches diagonal and mainstream QVGA (320 × 240 pixels), the pixel pitch is 120 μm, and the width of the subpixel of each color element Is 40 μm. When such a high-definition display element is to be formed by the relief printing method, a very high printing pattern accuracy of 5 μm or less is required.

  In addition, the organic light-emitting material changes the electrical and optical characteristics depending on the film thickness of the layer to be formed, the effluent from the printing plate during the printing process, and the foreign matter. Required.

  However, for example, in order to manufacture a display having the pixel size of QVGA, lines and spaces having a pitch of about 40 μm per subpixel are required. For this reason, if foreign matter adheres to the printing pattern on the plate surface immediately after plate making, a pattern defect occurs, adjacent organic light emitting layers are mixed, and printing failure such as color mixing or transfer failure such as film thickness variation occurs. Further, in a general plate making method, drying and post-exposure processes are performed after development, so that there is a high possibility that foreign matter will adhere.

  In such a relief printing plate having a fine pattern that requires high accuracy, there has been a case where a foreign matter size that has not been a problem in the conventional method of making a printing relief printing plate has become a problem.

  In addition, since various organic solvents are used when an organic light emitting material is made into an ink, a printing plate having solvent resistance has been demanded.

  The problem of printing defects such as printing pattern accuracy and transfer defects of such plates is also observed in printed electronics that require fine pattern formation, such as color filters, circuit substrates, thin film transistors, microlenses, and biochips. It is the same.

JP 2001-093668 A JP 2001-155858 A

  In printed electronics using letterpress printing, such as organic EL displays, the letterpress used to form a high-definition pattern with a uniform film thickness causes print defects and transfer defects even with the smallest foreign matter on the pattern on the plate surface. there is a possibility.

  Therefore, the present invention is capable of printing a high-definition pattern with a uniform film thickness and high definition by preventing printing defects and elution from the plate material due to foreign matter adhering to the plate surface, and preventing uneven transfer of ink on the plate. Is an issue.

In order to solve the above-mentioned problem, the invention according to claim 1 of the present invention is a printing relief plate in which dot-like or stripe-like periodic projections corresponding to a printing pattern are formed, Constructed by sequentially laminating an adhesive layer, a solvent-resistant layer, and a photosensitive resin layer on one surface of the substrate, and at least the top surface of the convex portion is polyvinyl carbazole or a derivative thereof, side chain or main chain is aromatic Protection composed of materials containing one or more selected from polyarylene derivatives having amines, arylamine derivatives, polymers containing aromatic amines of triphenyldiamine derivatives, polybiphenols containing siloxane crosslinkers, polystyrene A relief printing plate characterized in that a layer is formed.

The invention according to claim 1 of the present invention is a printing relief plate in which dot-like or stripe-like periodic projections corresponding to a printing pattern are formed, and the relief plate is bonded to one surface of a substrate. Layer, a solvent-resistant layer, and a photosensitive resin layer are sequentially laminated. Polyvinyl carbazole or a derivative thereof, a polyarylene derivative having an aromatic amine in the side chain or main chain, aryl on at least the top surface of the convex portion Since a protective layer made of a material containing one or more selected from amine derivatives, polymers containing aromatic amines of triphenyldiamine derivatives, polybiphenols containing siloxane crosslinkers, and polystyrene is formed, Solvent resistance with respect to the solvent of the coating ink to be used, characteristic deterioration due to penetration of the plate material, and mixing of foreign substances derived from the plate can be prevented. Furthermore, by forming a cross-linkable material in the coating ink to be printed, it prevents the plate-derived foreign matter and the plate material from being melted by the ink solvent, and is lyophilic with the coating ink to be printed. By increasing the thickness, formation of root snow on the plate can be stabilized, and variations in film thickness due to poor transfer of ink on the plate and uneven light emission can be reduced.

  In the invention according to claim 3 of the present invention, the protective layer is more compatible with the coating ink than the top surface of the convex portion without the protective layer, and the contact angle of the coating ink is 3. The relief printing plate according to claim 1, wherein the relief printing plate is 5 ° or more smaller than a top surface of the projection without the protective layer.

  In the invention according to claim 3 of the present invention, the protective layer is more compatible with the coating ink than the top surface of the convex portion without the protective layer, and the contact angle of the coating ink is the protective layer. Since it is 5 degrees or more smaller than the top surface of the convex part without a layer, the amount of ink transfer becomes even more uniform, and the variation in the thickness of the layer formed by printing can be significantly reduced. For example, the number of abnormal light emitting pixels of the organic EL element can be drastically reduced.

  The invention according to claim 4 of the present invention is the relief printing plate according to any one of claims 1 to 3, wherein the protective layer has a thickness of 10 nm to 10 μm.

  In the invention according to claim 4 of the present invention, since the thickness of the protective layer is 10 nm or more and 10 μm or less, the top surface of the convex part is completely coated to protect the convex pattern from damage due to foreign matter or impact. Moreover, the shape of the convex pattern is not blurred.

  In the invention according to claim 5 of the present invention, the layer under the protective layer is a photosensitive resin layer, and the thickness of the photosensitive resin layer is 20 μm or more and 100 μm including the thickness of the protective layer. It is the following, The relief printing plate in any one of Claims 1-4 characterized by the above-mentioned.

  In the invention according to claim 5 of the present invention, the layer under the protective layer is a photosensitive resin layer, and the thickness of the photosensitive resin layer is 20 μm or more and 100 μm or less including the thickness of the protective layer. Therefore, even when the substrate to be printed is a high-hardness material such as glass or metal, the pattern on the substrate to be printed or the substrate to be printed is not damaged, and the printing relief plate substrate and the photosensitivity In the vicinity of the interface of the resin layer or in the photosensitive resin layer, no mechanical deformation or destruction occurs, and the degree of swelling of the photosensitive resin layer by the solvent is small.

  The invention according to claim 6 of the present invention is a method for producing a printed matter, wherein the printed matter is produced by a printing machine using the relief printing plate according to any one of claims 1 to 5.

  Since the invention according to claim 6 of the present invention is manufactured by a printing press using the printing relief printing plate according to any one of claims 1 to 5, high-quality printed electronics with extremely few defects can be realized.

  As described above, the present invention can print a high-definition pattern with a uniform film thickness and high definition by preventing printing defects and elution from the plate material due to foreign matter adhering to the plate surface, and preventing uneven transfer of ink on the plate. There is an effect.

(A) is the plate base material before patterning, (b) is the cross-sectional schematic which shows the structure of the conventional printing relief plate after patterning about the conventional printing relief plate. In the printing relief plate of the present invention, (a) is a printing relief plate in which a protective layer is formed only on the convex portion, and (b) is a cross section showing the configuration of the printing relief plate in which a protective layer is formed on the entire plate. Schematic. The perspective view which shows schematically the structure of the printed matter manufacturing apparatus (printing machine) which manufactures printed matter using the relief printing plate of this invention. The cross-sectional schematic diagram which shows typically the structure of the organic EL element manufactured using the relief printing plate of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention can be utilized suitably as printed electronics which manufactures the display screen of a display. Examples of printed electronics include the production of organic EL elements and organic transistors. The use of the present invention is not limited to these.

  As shown in FIGS. 2A and 2B, the printing relief plate according to the embodiment of the present invention is formed on at least the photosensitive resin layer 104 of the conventional printing relief plate shown in FIG. A protective layer 205 is provided. Therefore, first, a conventional relief printing plate will be described.

  FIG. 1 schematically shows a configuration of a conventional printing relief plate and a plate substrate of this conventional printing relief plate. FIG. 1 (a) shows a plate substrate before plate making (convex pattern formation). FIG. 1B is a schematic cross-sectional view of the configuration, and FIG. 1B is a schematic cross-sectional view of a conventional relief printing plate after plate making. As shown in FIG. 1A, a conventional relief printing plate base material has a structure in which an adhesive layer 102, a solvent-resistant layer 103, and a photosensitive resin layer 104 are sequentially laminated on one surface of a base material 101. . The conventional relief printing plate shown in FIG. 1B is obtained by patterning the photosensitive resin layer 104 by a photolithography method.

As the substrate 101, a metal or a resin film can be used. By using a metal, since the whole base material 101 does not swell with respect to the solvent in the coating liquid, it can be suitably used as a plate having good dimensional stability. Examples of the metal used include Fe, Ni, Cu, and Zn. Further, an alloy of these metals such as stainless steel may be used.
When using a resin film, a plastic film such as a polyester film can be used.

  The adhesive layer 102 is a layer intended to enhance the adhesion between the solvent-resistant layer 103 and the substrate 101, and is not particularly limited as long as it is a resin material that is water-resistant and has good adhesion to a metal. As a resin satisfying these conditions, an epoxy-based or polyester urethane-based thermosetting resin is preferable.

  Since the solvent-resistant layer 103 is a layer for the purpose of protecting the adhesive layer 102, it is not particularly limited as long as it is a resin material having both solvent resistance and adhesiveness. As the resin, a resin in which the same material as the main component of the photosensitive resin layer 104 is added to the resin material of the adhesive layer 102 is preferable. While having solvent resistance, compatibility at the interface with the photosensitive resin layer 104 is improved, and adhesion can be improved.

  The photosensitive resin layer 104 only needs to have solvent resistance to the ink to be used. Nitrile rubber, silicone rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprene rubber, butyl rubber, acrylonitrile rubber, ethylene propylene rubber, urethane rubber In addition to rubber such as polyethylene, polystyrene, polybutadiene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyamide, polyethersulfone, polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyvinyl alcohol and the like and those Copolymers, natural polymers such as cellulose, fluoroelastomers, polytetrafluoroethylene, polyvinylidene fluoride, poly (vinylidene fluoride) and their copolymers. And although one or more of a fluorine resin can be selected from the viewpoint such as ease of processing, it is desirable to use a photosensitive resin.

  When an organic solvent is used as the coating solution, a water-developable photosensitive resin is preferable because of its high resistance to organic solvents. The water-developable photosensitive resin may be a known one, and examples thereof include a type having a hydrophilic polymer, a monomer containing an unsaturated bond, and a photopolymerization initiator as constituent elements. In this type, polyamide, polyvinyl alcohol and cellulose derivatives can be used as the hydrophilic polymer.

  In addition, 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. Of these, polyamide-based water-developable photosensitive resins are suitable from the viewpoint of printability.

  Moreover, it is preferable that the thickness of the photosensitive resin layer 104 is 20 micrometers or more and 100 micrometers or less including the thickness of the protective layer 205. FIG. When the thickness is less than 20 μm, the substrate to be printed or the pattern on the substrate to be printed may be damaged when the substrate to be printed is a material having high hardness such as glass or metal. When the thickness exceeds 100 μm, mechanical deformation or destruction occurs in the vicinity of the interface between the base material 101 and the photosensitive resin layer 104 or in the photosensitive resin layer 104, and the degree of swelling of the photosensitive resin layer 104 by the solvent Will become bigger.

  FIG. 2 is an explanatory view schematically showing the configuration of the printing relief plate according to the embodiment of the present invention. FIG. 2A is a schematic cross-sectional view of a printing relief plate in which a protective layer 205 is provided only on a convex portion immediately after a convex pattern is formed by a photolithography method. FIG. 2B is a schematic cross-sectional view of a printing relief plate in which the protective layer 205 is provided on the entire plate. When there is a large amount of ink and there is a concern about the ink flowing into the plate bottom (concave portion), it is desirable that the protective layer 205 is formed into a convex pattern only on the convex portion as shown in FIG. When there is no concern about the amount of ink flowing into the plate bottom (concave portion), a printing relief plate may be formed as shown in FIG.

The protective layer 205 is a coating ink used for forming this film on the layer above the solvent-resistant layer 103 before forming a crosslinkable film containing a crosslinkable group by a relief printing method. In order to form a film using the same organic material, in consideration of the influence of heat of the layer below the protective layer 205, photocrosslinking is desirable, but the present invention is not limited thereto.
Moreover, the crosslinkable group described here means a group having a “part having a crosslinking performance” by heat, light, acid, electron beam or the like such as a known unsaturated double bond, epoxy group, or octacene.
As a material used for the protective layer 205, when printing a polymer organic EL element, polyvinylcarbazole or a derivative thereof, a polyarylene derivative having an aromatic amine in a side chain or a main chain, an arylamine derivative, a triphenyldiamine derivative, or the like And polymers containing aromatic amines.
In the case of printing the gate insulating film of the organic TFT, polybiphenol containing a siloxane cross-linking agent, polystyrene, and the like are exemplified, but not limited thereto.

The protective layer 205 is generated after the development process until the printing plate is started to be used. The protective layer 205 has a protective layer thickness of 10 nm because it is one of the purposes to protect the adhered foreign matter and the convex pattern from damage due to impact. The thickness is preferably 10 μm or less. In the case of 10 nm or less, since the surface roughness of the photosensitive resin layer 104 is about 10 nm, it cannot be completely covered. Scratches due to foreign matters cannot be protected, and the convex pattern can be sufficiently protected with a thickness of 10 μm or more. However, the convex pattern is blurred and the influence of the line width is increased in high-definition printing. In addition, when only a thin film can be formed by a single film formation, it is necessary to form the film multiple times, which requires cost and time.
In addition, since the protective layer 205 is intended to increase the affinity with the coating ink and make the amount of ink transfer on the plate uniform, the contact angle on the protective layer is smaller than that without the protective layer. It is preferable that the angle is smaller than 5 degrees. When the difference is 5 degrees or less, there is almost no difference in affinity, so the effect of making the ink transfer amount uniform cannot be expected.

  As a method for producing a relief printing plate according to an embodiment of the present invention, a photosensitive resin layer of a resin plate material is pattern-exposed using a photomask to cure the resin, and the uncured portion of the resin is washed away and developed. A publicly known method such as a photolithographic method for forming a relief having a predetermined pattern by performing drying and post-exposure after development and laser ablation or cutting can be used. It is desirable to use a photolithography method using a resin.

In the method for producing a relief printing plate according to the embodiment of the present invention, the protective layer 205 is formed after the development step.
When the protective layer 205 is formed on the convex portion, a film is formed only on the convex portion by a relief printing method, a thermal crosslinking or photocrosslinking method, a spin coating method, a spray method, or a die coating method as a direct coating. After a film is uniformly formed by a coating method, it can be selectively formed by a photolithography method, laser ablation or cutting.

  Next, the manufacturing method of the printed matter using the relief printing plate concerning embodiment of this invention is demonstrated.

  FIG. 3 schematically shows a configuration of a printed material manufacturing apparatus (printing machine) using the relief printing plate according to the embodiment of the present invention. For example, as shown in FIG. 3, the coating liquid is supplied to the anilox roll 303 which is an inking device to the printing relief plate 301 from the ink replenishing device 306 through the liquid passing portion 307, and is supplied to the anilox roll 303. Excessive coating liquid is removed by a doctor device (not shown).

In addition to the drop-type replenishing device, the ink replenishing device 306 may be a coater such as a fountain roll, a slit coater, a die coater, or a cap coater, or a combination thereof. In addition to the doctor roll, a doctor blade can be used for the doctor device.

  After the excess coating liquid is removed by the doctor device, inking to the printing relief plate 301 according to the embodiment of the present invention is performed. The coating liquid inked into the printing relief plate 301 attached to the side surface portion of the plate cylinder 302 is printed on the printing substrate 305 on the surface plate 304. In addition, although the material of the to-be-printed base material 305 is not ask | required, paper, a plastic film, glass, a metal etc. can be mentioned, for example. The coating liquid printed on the substrate to be printed 305 is dried as necessary to form a printed matter.

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 relief printing plate according to the embodiment of the present invention, but the present invention is not limited to this.
First, the structure of an organic EL element is demonstrated using the cross-sectional schematic diagram of the organic EL element of FIG. In addition, as a driving method of the organic EL element, there are a passive matrix method and an active matrix method. In the manufacturing method using the printing relief plate according to the embodiment of the present invention, both the passive matrix method and the active matrix method are used. Applicable.

  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. 4, the organic EL element manufactured by this invention has the 1st electrode 402 in the stripe form as an anode on the board | substrate 401. As shown in FIG. The partition wall 403 is provided between the first electrodes, and preferably covers the end portion of the first electrode 402 for the purpose of preventing a short circuit due to burrs at the end portion of the first electrode.

  The organic EL element manufactured according to the present invention is an organic EL layer that is formed on the first electrode 402 and includes an organic light emitting layer and a light emission auxiliary layer in a region (light emitting region L, pixel portion) partitioned by the partition 403. have. 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. FIG. 4 shows a structure having a stacked structure of a hole injection layer 404 that is a light emission auxiliary layer, an interlayer 405, and an organic light emitting layer 406 as an organic EL layer.

  Next, a second electrode 407 is disposed on the organic light emitting layer 406 as a cathode so as to face the first electrode 402 that is an anode. 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, 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, a sealing body 408 with a glass cap or the like is provided on the entire effective pixel, and an adhesive. It is attached to the substrate 401 via 409.

  The organic EL device produced according to 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. Contrary to FIG. 4, 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. In addition, sealing with a passivation layer and / or a protective layer that protects against external stress to protect the organic light emitting layer and electrodes from the ingress of external oxygen and moisture instead of a sealing body such as a glass cap. A substrate may be provided.

  Next, a method for manufacturing an organic EL element according to an embodiment of the present invention will be described.

  As the substrate 401 of the organic EL element, 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 401. 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. These plastic films and sheets have a metal oxide thin film, a metal fluoride thin film, a metal nitride thin film, a metal oxynitride thin film, or a polymer resin film for the purpose of preventing moisture from entering the organic light emitting layer. A stacked layer may be used as the substrate 401.

  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.

  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 403 can be controlled by conditions such as the number of rotations when spin coating is performed, but there is a limit height in one coating, and if it is higher than that, the spin coating is performed multiple times. Is used.

  When the partition 403 is formed by a photolithography method using a photosensitive material, the shape of the partition 403 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 403, the end of the partition wall 403 has a forward tapered shape. The type, concentration, temperature, or development time of a certain developer may be controlled. If the developer is thinned, the temperature is about room temperature, and the development time is increased, the end of the partition wall 403 becomes a forward taper shape, and the development conditions are such that the concentration of the developer is high, the temperature is high, and the development time is shortened. In this case, the end of the partition wall 403 has 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.

After the partition 403 is formed as described above, the hole injection layer 404 is formed next. Examples of the hole injection material for forming the hole injection layer 404 include polyaniline derivatives, polythiophene derivatives, polyvinylcarbazole (PVK) derivatives, poly (3,4-ethylenedioxythiophene) (PEDOT), and the like. These materials are dissolved or dispersed in a solvent to form a hole transport material ink, which is formed using the relief printing method according to the present embodiment.
In that case, it is important that the selected hole transport material has compatibility with the light emitting material, and the hole transport material has an ionization potential (IP) difference of 0.2 eV or less with respect to the light emitting material. is there.
Note that the volume resistivity of the formed hole injection layer 404 is 1 × 10 ⁶ Ω · c from the viewpoint of luminous efficiency.
m or less is preferable.
When an inorganic material is used as the hole injecting material, the inorganic materials include Cu ₂ O, Cr ₂ O ₃ , Mn ₂ O ₃ , FeOx (x ≧ 0.1), NiO, CoO, Pr ₂ O ₃ , Inorganic materials such as Ag ₂ O, MoO ₂ , Bi ₂ O ₃ , ZnO, TiO ₂ , SnO ₂ , ThO ₂ , V ₂ O ₅ , Nb ₂ O ₅ , Ta ₂ O ₅ , MoO ₃ , WO ₃ , MnO ₂ Is formed by vapor deposition or sputtering. However, the material is not limited to these.

Examples of the solvent for dissolving or dispersing the hole injection material include toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, isopropanol, ethylene glycol, propylene glycol, polyethylene glycol, glycerin, and ethyl acetate. , Butyl acetate, isopropyl acetate, methyl cellosolve, ethyl cellosolve, methyl cellosolve, ethyl cellosolve, butyl cellosolve, ethyl lactate, ethylene glycol diethyl ether, 1-propanol, methoxypropanol, ethoxypropanol, water, etc. Etc.
Moreover, surfactant, antioxidant, a viscosity modifier, a ultraviolet absorber, etc. may be added as needed.

Further, when printing, the viscosity of the hole injection layer ink is preferably 5 to 200 mPa · s.
In the relief printing method used in the present embodiment, the ink is first transferred from the anilox to the relief plate, but at a viscosity of 200 mPa · s or more, after the ink is transferred from the anilox to the relief plate, Insufficient ink leveling causes unevenness.
In addition, when the pressure is 5 mPa · s or less, the mottling unevenness is likely to occur in the pixel, causing the unevenness.

  The solid content concentration of the hole injection layer ink is preferably 0.5 to 4.0%. This is because, in the hole transport ink used in the present embodiment, when the concentration is 4.0% or more, the stability of the ink is deteriorated, which causes ink aggregation and unevenness of the hole transport layer.

Next, after forming the hole injection layer 404 as described above, an interlayer 405 is formed.
Examples of the material used for the interlayer 405 include polymers containing aromatic amines such as polyvinyl carbazole or derivatives thereof, polyarylene derivatives having aromatic amines in the side chain or main chain, arylamine derivatives, and triphenyldiamine derivatives. Each material contains a cross-linking group for laminating the organic light emitting layer 406 above.

These interlayer materials are dissolved or stably dispersed in a solvent to form an interlayer ink. First, on the convex portions of the printing relief plate, the coating is uniformly applied by a spin coating method, a spray method, or a direct coating method such as a die coating method. After the film is formed, it is formed by a relief printing method using a relief printing plate on which a protective layer 205 crosslinked by baking, light irradiation sintering or the like is formed.
Examples of the solvent for dissolving or dispersing the interlayer material include toluene, xylene, acetone, anisole, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, or a mixed solvent thereof. Among these, aromatic organic solvents such as toluene, xylene, and anisole are preferable from the viewpoint of solubility of the organic light emitting material.

Next, the organic light emitting layer 406 is formed. The organic light emitting layer 406 is a layer that emits light by passing an electric current. The organic light emitting material forming the organic light emitting layer 406 is, for example, a coumarin type, a perylene type, a pyran type, an anthrone type, a porphyrene type, a quinacridone type, N, N'-dialkyl-substituted quinacridone-based, naphthalimide-based, N, N'-diaryl-substituted pyrrolopyrrole-based, iridium complex-based luminescent dyes dispersed in polymers such as polystyrene, polymethyl methacrylate, polyvinyl carbazole, etc. And polyarylene-based, polyarylene vinylene-based, and polyfluorene-based polymer materials.

  These organic light emitting materials are dissolved or stably dispersed in a solvent to form 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 these, aromatic organic solvents such as toluene, xylene, and anisole are preferable from the viewpoint of solubility of the organic light emitting material. Moreover, surfactant, antioxidant, a viscosity modifier, a ultraviolet absorber, etc. may be added to organic luminescent ink as needed.

  The organic light emitting layer 406 is formed by a relief printing method using the same printing plate as that used for forming the interlayer.

The viscosity of the organic light emitting ink is preferably 5 to 100 mPa · s.
In the relief printing method used in the present embodiment, the ink is first transferred from the anilox to the relief plate. However, at a viscosity of 100 mPa · s or more, after the ink is transferred from the anilox to the relief plate, Insufficient ink leveling causes unevenness.
In addition, when the pressure is 5 mPa · s or less, the mottling unevenness is likely to occur in the pixel, causing the unevenness.

Next, after forming the organic light emitting layer 406 as described above, the cathode layer 407 is formed in a line pattern orthogonal to the line pattern of the pixel electrode 402. As the material of the cathode layer 407, a material corresponding to the light emission characteristics of the organic light emitting layer 405 can be used. For example, simple metals such as lithium, magnesium, calcium, ytterbium, and aluminum, and stable metals such as gold and silver can be used. And alloys thereof.
Alternatively, a conductive oxide such as indium, zinc, or tin can be used. Examples of the method for forming the cathode layer include a method using a vacuum vapor deposition method using a mask.

Note that the organic EL element of this embodiment has a structure in which a hole injection layer 404, an interlayer 405, and an organic light emitting layer 406 are stacked from the anode layer side between a pixel electrode 402 that is an anode and a cathode layer 407. In addition to the hole injection layer 404 and the organic light emitting layer 406, a layered structure in which layers such as a hole blocking layer, an electron transport layer, and an electron injection layer are selected as necessary can be formed between the anode layer and the cathode layer.
The formation method of the present invention can also be used when forming these layers.

  Finally, in order to protect these organic EL constituents from external oxygen and moisture, an organic EL element can be obtained by hermetically sealing with a glass cap 408 and an adhesive 409. In the case where the substrate 401 has flexibility, sealing may be performed using a sealing body including a sealing material and a flexible film (resin layer).

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 1 × 10 ⁻⁶ g / m ² / day or less.

Examples of the resin layer include a photo-curing adhesive resin made of an epoxy resin, an acrylic resin, a silicone resin, a thermosetting adhesive resin, a two-component curable adhesive resin, and an ethylene ethyl acrylate (EA) polymer. 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 402, the organic light emitting layer 406, the light emission auxiliary layer, and the second electrode 407 are formed is bonded to the sealing body 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 of the present invention will be specifically described below.

[Example 1]

<Method for forming letterpress for printing>
A steel material having a thickness of 0.3 mm is used as the base material 101, a photosensitive resin layer 104 having a polyamide resin as a main component and a thickness of 0.03 mm, and 0 formed between the photosensitive resin layer 104 and the base material 101. A plate substrate for letterpress printing is prepared which comprises a 0.03 mm thick epoxy resin adhesive layer 102 and a 0.03 mm thick epoxy resin thermosetting solvent-resistant layer 103 containing 10% polyamide resin component. did. The plate base material was exposed through a photomask having a negative pattern formed thereon, developed with water, and post-exposed to produce a relief printing plate having a desired pattern. The convex pattern was an independent pattern with a 106 μm pitch having a line width of 60 μm and a space of 46 μm in a central 5-inch diagonal region.
After that, a 5-inch diagonal patterning is performed by using a slit coater with an ink in which a polyvinyl carbazole derivative, which is a cross-linkable interlayer 405 material, used in the production of an organic EL element is dissolved in toluene to a concentration of 3%. After coating on the formed region, only the convex pattern was cross-linked by xenon pulse irradiation through a photomask, and the periphery was rinsed with toluene, thereby forming 40 nm of the protective layer 205 only on the convex pattern.

<Organic EL device manufacturing method>
As the substrate 401, an active matrix substrate including a thin film transistor functioning as a switching element provided on a support was used. The size of the substrate is 200 mm x 200 mm, and a display with a diagonal of 5 inches and a pixel count of 240 x 320 (equivalent to QVGA) is arranged in the center, the pixel aperture is 80 x 318 μm, and the partition wall height is 3 μm.

As a hole injection layer 504 on the substrate surface, molybdenum oxide (MoOx) having a thickness of 20 nm.
Was formed by sputtering.

  Next, this substrate is set in a printing machine using an ink obtained by dissolving a polyvinyl carbazole derivative, which is a material of the interlayer 405, in toluene so as to have a concentration of 0.5%. The substrate is set directly above the pixel electrode 402 partitioned by the insulating layer. The interlayer was printed by letterpress printing according to the line pattern. At this time, the printing plate used was the plate prepared above, and the anilox roll was 300 lines / inch. The film thickness of the interlayer 405 after printing and drying was 30 nm.

  Next, an organic light-emitting ink in which a polyphenylene vinylene derivative, which is a blue organic light-emitting material, is dissolved in toluene so as to have a concentration of 1% is used, this substrate is set in a printing machine, and a pixel electrode 402 sandwiched between insulating layers. The blue organic light-emitting layer 405 was printed by letterpress printing with the line pattern aligned directly above. At this time, the printing plate used was the same plate as that used for printing with the interlayer 405, and the anilox roll used 150 lines / inch. The thickness of the organic light emitting layer 405 after printing and drying was 60 nm.

  Next, by vacuum evaporation, an electron injection layer (not shown) was continuously formed so as to cover the entire pixel with a Ba film of 4 nm and a second electrode (cathode) 407 of an Al film of 200 nm.

  Thereafter, a cap glass 408 and an adhesive 409 were placed so as to cover the light emitting region, and the adhesive was heat-cured at about 90 ° C. for 1 hour and hermetically sealed to produce an active matrix driving type organic EL panel.

[Comparative Example 1]

<Method for forming letterpress for printing>
A steel material having a thickness of 0.3 mm is used as the base material, a 0.03 mm-thick photosensitive resin layer 104 mainly composed of a polyamide-based resin, and an intermediate portion between the photosensitive resin layer 104 and the base material 101 is formed. A plate base plate for letterpress printing comprising an adhesive layer 102 of an epoxy resin having a thickness of 03 mm and a thermosetting solvent-resistant layer 103 containing a polyamide resin component of 10% in an epoxy resin having a thickness of 0.03 mm was prepared. . The plate base material was exposed through a photomask having a negative pattern formed thereon, developed with water, and post-exposed to produce a relief printing plate having a desired pattern. The convex pattern was an independent pattern with a 106 μm pitch having a line width of 60 μm and a space of 46 μm in a central 5-inch diagonal region.

<Organic EL device manufacturing method>
The production method was the same as in Example 1 except that the printing relief plate used was different.

(Evaluation for Example 1 and Comparative Example 1)
After producing 10 organic EL panels as in Example 1 and Comparative Example 1, the number of foreign matters is evaluated by microscopic observation, the pixels having an abnormality in the light emission shape in the display state, and the peripheral pixels are measured by luminance measurement. On the other hand, pixels having a luminance difference of 20% or more and those having the highest luminance emission location off the center of the pixel were regarded as abnormal emission pixels, and the average number per pixel was compared. The results are shown in Table 1, and after measuring several film thicknesses of 10 panels in a plane with a step gauge, the average film thickness in the plane and the variation 3σ were evaluated. The results are shown in Table 2. It was.
As shown in Table 1, the number of foreign matters in Example 1 is about half that in Comparative Example 1, and the number of short pixels due to foreign matters is reduced to one-eighth or less. I understand that It can also be seen that the number of abnormal light emitting pixels is also greatly reduced. The cause of abnormal light emission is the deviation of the film thickness of the deposited organic film and the difference in film thickness, and the fact that abnormal light emission due to foreign matter is small is obtained from the previous knowledge. Since there was no foreign matter and the variation in the film thickness of Example 1 was small from the results of Table 2, the formation of an organic film with little variation in Example 1 reduced abnormal light emission. it is conceivable that.
That is, abnormal light emission can be suppressed by forming the organic film with little variation in Example 1.

DESCRIPTION OF SYMBOLS 101 ... Base material 102 ... Adhesive layer 103 ... Solvent-resistant layer 104 ... Photosensitive resin layer 205 ... Protective layer 301 ... Printing Top plate 302 ... Plate cylinder 303 ... Anilox roll 304 ... Surface plate 305 ... Substrate for printing 306 ... Ink replenisher (ink chamber)
307: Liquid passing part 401: Substrate (substrate with TFT)
402... Pixel electrode (first electrode)
403... Partition 404... Hole injection layer 405... Interlayer 406... Organic light emitting layer 407... Second electrode 408. Cap 409: Adhesive

Claims (4)

A printing relief plate having dot-like or stripe-like periodic projections corresponding to the printing pattern, wherein the relief plate has an adhesive layer, a solvent resistant layer, a photosensitive resin layer on one surface of the substrate. It is configured by sequentially laminating, and at least the top surface of the convex portion has polyvinyl carbazole or a derivative thereof, a polyarylene derivative having an aromatic amine in a side chain or a main chain, an arylamine derivative, an aromatic amine of a triphenyldiamine derivative. A relief printing plate comprising a protective layer made of a material containing one or more selected from a polymer containing siloxane, a polybiphenol containing a siloxane crosslinking agent, and polystyrene .   2. The relief printing plate according to claim 1, wherein the protective layer has a thickness of 10 nm to 10 μm.   The layer under the protective layer is a photosensitive resin layer, and the thickness of the photosensitive resin layer is 20 μm or more and 100 μm or less including the thickness of the protective layer. The letterpress for printing described in 1. It manufactures with the printing machine using the relief printing plate in any one of Claim 1 to 3, The manufacturing method of the printed matter characterized by the above-mentioned.