JP2014061653A - Letterpress printer and method of producing polymer organic el display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a letterpress printer capable of forming a printing pattern free of printing defects stably on a substrate without inspection of the substrate and a method of producing a polymer organic EL display element.SOLUTION: A letterpress printer prints a pattern on a printing substrate to be printed (hereafter abbreviated as 'a substrate') by using a letterpress and is provided with printing means and pattern inspection means. The printing means includes the letterpress, a plate cylinder mounted on the surface of the letterpress, an ink supply device supplying an ink to the surface of the letterpress and a movable platen loaded with and carrying the substrate. The pattern inspection means includes a roll for inspection arranged in a moving mechanism for the movable platen and an inspection device inspecting a pattern printed on the roll for inspection.

Description

  The present invention relates to a printing apparatus for manufacturing a polymer organic EL display panel and a method for manufacturing a polymer organic EL display element.

  An organic electroluminescence (hereinafter EL) element is a light-emitting element having a structure in which an organic light-emitting layer made of an organic light-emitting material is formed between an anode and a cathode that face each other. In order to obtain efficient light emission, the film thickness of the organic light emitting layer is an important factor for obtaining efficient light emission. Therefore, it is necessary to control the film thickness at about several tens of nm. Further, in order to make this a display, it is necessary to pattern it with high definition.

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

  In general, a low molecular weight material forms a thin film on a substrate by resistance heating vapor deposition (vacuum vapor deposition) or the like. In the case of full-color organic EL display elements, a method is employed in which a luminescent material having a different emission color is deposited on each pixel using a mask having a pattern corresponding to the pixel shape of each color. Although this method is an excellent method for uniformly forming a thin film shape, there is a problem in that the mask pattern accuracy is difficult to be obtained when the deposited substrate becomes large.

  On the other hand, in the case of polymer materials, a method in which an organic light emitting material is dissolved or dispersed in a solvent to form an ink and a thin film is formed by a wet coating method is mainly used. As the wet coating method, there are a spin coating method, a bar coating method, a protruding coating method, a dip coating method, etc., but it is difficult to use these methods for high-definition patterning and color separation for full color. . Therefore, it is considered that pattern printing by an ink jet method or a printing method is effective as a means for patterning the organic light emitting material layer for full color.

  As one of high-definition patterning methods, for example, there is an ink jet method in which an organic light emitting material dissolved in a solvent is jetted onto a substrate from an ink jet nozzle and dried on the substrate (Patent Document 1). In this method, since the ink droplets ejected from the nozzle are spherical, the ink spreads in a circular shape when landing on the substrate, and the formed pattern shape is not linear or has landed. There is a problem that the linearity of the pattern cannot be obtained due to poor accuracy.

  On the other hand, letterpress printing, reversal printing, screen printing, and the like have been proposed as pattern forming methods by printing. In organic EL display elements and displays, a glass substrate is often used as a base material, and a method using a hard printing plate made of metal such as a gravure printing method is not suitable. Therefore, a printing method using a rubber printing plate having elasticity, an offset printing method using a rubber printing blanket, a relief printing plate using a photosensitive resin plate mainly composed of elastic rubber or other resin. The printing method is considered an appropriate printing method. Actually, as a trial of these printing methods, a pattern printing method by offset printing (Patent Document 2), a pattern printing method by letterpress printing (Patent Document 3), and the like have been proposed. In particular, the method by letterpress printing is excellent in pattern formation accuracy and film thickness uniformity, and is most suitable as a method for producing an organic EL display element by printing.

  FIG. 1 illustrates an example of a printing apparatus for forming a light emitting portion of an organic EL display element by a relief printing method. Ink is stored in the ink pan 3 shown in FIG. After the ink is supplied to the anilox roll 4 in the ink pan 3, excess ink on the roll surface is scraped off by the doctor 5, and the ink is stored only in the inside of the hole. The ink inside the hole is transferred onto the image forming portion of the relief plate 1 wound around the plate cylinder 2 that rotates relative to the anilox roll 4, and forms a thin film of ink there. Further, the thin film formed on the image forming unit is transferred onto a substrate (hereinafter referred to as a substrate) 6 that moves relative to the plate cylinder 2.

  When an organic EL display element is manufactured by a relief printing method, the transfer pattern on the printing plate has a plurality of transfer patterns for forming the same color light emitting part among a plurality of light emitting parts constituting each pixel of the organic EL display element. The organic light emitting layer pattern is obtained by sequentially printing each light emitting portion.

  As described above, in the letterpress printing method, the ink is transferred from the anilox roll to the resin letterpress, and further the ink on the resin letterpress is transferred to the substrate to obtain a desired organic light emitting layer pattern. Here, it is formed on the resin letterpress. The resin pattern to be formed needs to be a pattern opposite to a desired organic light emitting layer pattern formed on the substrate. However, if the resin pattern formed on the resin relief plate has chips, protrusions, or adhered foreign matter, a print defect caused by them occurs in the pattern formed on the substrate, and further, the print defect is There was a problem that it occurred as a common defect in all the substrates printed continuously.

  For this reason, a method for preventing the occurrence of continuous print defects by removing the printed substrate and carrying out the inspection is adopted, but the characteristics of the organic light emitting layer deteriorate due to the inspection light during the inspection or the inspection environment. Will be treated as defective. For this reason, there exists a subject of leading to a yield fall, cost increase, etc.

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

  The present invention has been made to solve the above problems, and a relief printing apparatus and a polymer organic EL display capable of stably forming a print pattern free from printing defects on a substrate without inspecting the substrate. It is an object to provide an element manufacturing method.

As means for solving the above problems, the invention according to claim 1
A relief printing apparatus for printing a pattern on a substrate to be printed (hereinafter referred to as a substrate) using a relief plate,
The relief printing apparatus includes a printing unit and a pattern inspection unit.
The printing means includes the relief plate, a plate cylinder on which the relief plate is mounted, an ink supply unit that supplies ink to the surface of the relief plate, and a moving surface plate that places and conveys the substrate.
In the relief printing apparatus, the pattern inspection means includes: an inspection roll provided in a moving mechanism of the movable surface plate; and an inspection apparatus that inspects a pattern printed on the inspection roll. is there.

According to a second aspect of the present invention, the inspection apparatus includes an illumination unit that irradiates the inspection roll with illumination light for inspection, and an inspection camera that captures an image of a pattern printed on the inspection roll. The relief printing apparatus according to claim 1, wherein:

  According to a third aspect of the present invention, when the pattern printed on the inspection roll is determined to be normal by the pattern inspection means, printing on the substrate is started. It is a letterpress printing apparatus.

  According to a fourth aspect of the present invention, in the relief printing apparatus according to any one of the first to third aspects, the pattern inspection by the pattern inspection means is performed every preset number of printed inspection cycles. is there.

  The invention according to claim 5 is provided with a cleaning means for cleaning the pattern printed on the inspection roll with a cleaning liquid, and a drying means for drying the cleaning liquid adhered on the inspection roll. Item 5. The relief printing apparatus according to any one of Items 1 to 4.

  A sixth aspect of the present invention is a polymer organic EL display element manufacturing method for manufacturing a polymer organic EL display element using the relief printing apparatus according to any one of the first to fifth aspects. .

  According to the relief printing apparatus and the polymer organic EL display element manufacturing method according to the present invention, since the pattern printed on the inspection roll is not inspected directly on the substrate, the conventional method is obtained. Yield can be improved compared to.

The figure which shows an example of the printing apparatus for forming a light emission part by a relief printing method. The figure which shows the relief printing apparatus by this invention. The figure which shows the cross section of the letterpress which concerns on embodiment of this invention. The figure which shows the pattern inspection means which concerns on embodiment of this invention in detail. The figure which shows the inspection roll washing | cleaning means and inspection roll drying means of the relief printing apparatus of this invention in a cross section. The flowchart which shows the operation | movement of the whole relief printing apparatus of this invention.

  FIG. 2 shows a relief printing apparatus according to the present invention. The relief printing apparatus of the present invention comprises printing means and pattern inspection means. The printing means 100 includes a relief plate 101, a rotary plate cylinder 102 having the relief plate 101 mounted on the surface, an ink supply unit 108 that supplies ink to the surface of the relief plate 101, and a light emission pattern formed around the plate cylinder 102. And a moving surface plate 107 that conveys the forming substrate 106. The ink supply unit 108 includes an anilox roll 104, an ink pan 103 that supplies ink to the anilox roll 104, and a doctor 105 that removes excess ink on the anilox roll 104. The pattern inspection unit 202 includes an inspection roll 200 and an inspection apparatus 201 that inspects a pattern printed on the inspection roll.

  Next, each configuration of the present invention will be described in detail. The plate cylinder 102 is disposed on the movable surface plate 107 and is supported rotatably at a fixed position. The relief plate 101 is mounted on the peripheral surface of the plate cylinder 102. The anilox roll 104 is installed so as to be parallel to the rotational axis of the plate cylinder 102 and to be in contact with the plate surface of the surface of the relief plate 101. The ink pan 103 is filled with ink, and the anilox roll 104 is installed so as to be immersed in the ink inside the ink pan 103. The substrate 106 is placed on the moving surface plate 107. The moving surface plate 107 is installed so as to move horizontally in a direction perpendicular to the rotation axis of the plate cylinder 102 and in a direction indicated by an arrow 107a.

  Further, the printing apparatus according to the embodiment of the present invention includes an inspection roll 200 and an inspection apparatus 201 that move along with the movable surface plate 107. A support base 400 is positioned horizontally below the plate cylinder 102, and the movable surface plate 107, the inspection roll 200, and the inspection apparatus 201 are arranged on the support base 400 via a guide with a rotation axis of the plate cylinder 102. It is installed so that it can move in the horizontal direction 107a perpendicular to the axis.

  In the printing apparatus having the above-described configuration, as the anilox roll 104 rotates, the ink supplied from the ink pan 103 is uniformly held on the surface of the anilox roll 104 and then transferred to the plate surface of the relief plate 101 mounted on the plate cylinder 102. The The substrate 106 is fixed on the moving surface plate 107 and moved to the printing start position while adjusting the position by a position adjusting mechanism (not shown) between the pattern of the relief plate 101 and the pattern forming position of the substrate 106. From the printing start position, the substrate 106 contacts the convex portion of the relief plate 101 and moves in synchronization with the rotation of the plate cylinder 102, and ink is transferred from the relief plate 101 to a predetermined position on the substrate 106 and patterned. After the ink pattern is formed on the substrate 106, it is dried by an oven or the like as necessary.

  The anilox roll 104 according to the embodiment of the present invention supplies ink to the relief plate 101 while rotating at the same peripheral speed as the peripheral speed of the plate cylinder 102. The anilox roll 104 may be made of chrome or ceramics, and fine holes, recesses, and cellular patterns for holding ink are formed on the outer peripheral surface of the anilox roll 104.

  The ink pan 103 according to the embodiment of the present invention includes an ink reservoir that immerses the lower peripheral surface portion of the anilox roll 104, a coater such as a dripping type inking unit, a fountain roll, a die coater, and a cap coater, or a combination thereof. Things can be used. Further, an ink replenishing device (not shown) for replenishing ink to the ink pan 103 and an ink tank (not shown) for storing ink are connected.

  A doctor 105 is also provided in order to uniformly supply ink onto the anilox roll 104. The doctor 105 has a blade shape or a roll shape, and any of them may be used. When the ink pan 103 is an ink reservoir, the doctor 105 is positioned between the ink reservoir and the contact point between the anilox roll 104 and the relief plate 101 in the rotational direction of the anilox roll 104. It is preferable to fall into the pool.

  FIG. 3 is a view showing a cross section of the relief plate 101 according to the embodiment of the present invention. The relief plate 101 is composed of a surface layer 101a and a base material layer 101b.

  The material of the surface layer 101a used for the relief plate 101 according to the embodiment of the present invention is only required to have mechanical strength against printing, and is made of polyethylene, polystyrene, polybutadiene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyamide. , Known synthetic resins such as polyethersulfone, polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, and polyvinyl alcohol, known metals such as iron, copper, and aluminum, or laminates thereof.

As the base material layer 101b constituting the relief plate 101, one that maintains high dimensional stability is desirable, and a metal is suitably used as a material used as the base material. Examples of the metal used as the base material include iron, aluminum, copper, zinc, nickel, titanium, chromium, gold, silver, alloys thereof, and laminates. In particular, iron is the main component in terms of workability and economy. The steel base material and aluminum base material which can be used can be used suitably.

  The surface layer 101a of the relief plate 101 is a resin layer, and as a method of forming a convex portion on the surface, a photolithography method using a positive photosensitive resin, a photolithography method using a negative photosensitive resin, injection molding, Various pattern molding methods such as letterpress printing method, intaglio printing method, lithographic printing method, stencil printing method and laser ablation method can be used, but from the viewpoint of high definition of pattern, photolithography using photosensitive resin In order to form a relief plate that satisfies the required accuracy, a photolithography method using a negative photosensitive resin is most desirable.

  When the photolithographic method using a photosensitive resin is applied as the convex pattern forming method, the convex of the relief plate 101 is formed from a plate-shaped photosensitive resin laminate in which a base material layer, a reflection suppressing layer, and a photosensitive resin layer are sequentially laminated. It is most desirable to form the part. As a method for molding the photosensitive resin layer, a known method such as an injection molding method, a protruding molding method, a laminating method, a bar coating method, a slit coating method, or a comma coating method can be used.

  The resin layer of the surface layer 101a of the relief plate 101 only needs to have a solvent resistance to ink as a resin to be used. In addition to rubbers such as propylene rubber and urethane rubber, polyethylene, polystyrene, polybutadiene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyamide, polyether sulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polyvinyl alcohol, etc. Synthetic resins, their copolymers, cellulose derivatives, etc., fluoroelastomers, polytetrafluoroethylene, polyvinylidene fluoride, poly (vinylidene fluoride) and their It is possible to select one or more of a fluorine-based resin such as polymer.

  The relief plate 101 according to the embodiment of the present invention is used by mounting the relief plate 101 having the projection pattern formed on the substrate as described above on the plate cylinder 102. A convex pattern may be formed on the plate cylinder 102.

  The ink to be used is adjusted to a suitable viscosity in consideration of the coating from the ink pan 103 to the anilox roll 104 and the transfer from the anilox roll 104 to the relief plate 101, and the viscosity of the ink should be 5 to 180 mPa · s. desirable. In the relief printing apparatus used in the present embodiment, the ink is first transferred from the anilox roll 104 onto the relief plate 101, but after the ink is transferred from the anilox roll 104 to the relief plate 101 at a viscosity of 180 mPa · s or more, Ink is not leveled sufficiently on the relief plate 101, causing unevenness. In addition, at 5 mPa · s or less, when the image is transferred to the substrate 106, unevenness is likely to occur in the pixel, causing unevenness.

  The amount of ink transferred from the anilox roll 104 onto the relief plate 101 is determined by the film thickness to be formed on the substrate 106, but the ink transferred onto the relief plate 101 by adjusting the ink density and the cell volume of the anilox roll 104. It is desirable to keep the amount constant.

  FIG. 4 is a diagram showing in detail the pattern inspection means 202 according to the embodiment of the present invention. The inspection roll 200 comes into contact with the convex portion of the relief plate 101 from the printing start position in which ink is supplied to the relief plate 101. It is configured to rotate in synchronization with the rotation of the plate cylinder 102 and to transfer ink from the relief plate 101 to the peripheral surface of the inspection roll 200 to obtain an ink pattern. The transferred ink pattern is detected for defects and foreign matter in the ink pattern by an inspection apparatus 200 having an illumination means 203 and an inspection camera 204 installed toward the surface of the inspection roll 201.

  The inspection roll 200 according to the embodiment of the present invention preferably has a smooth surface such as a chrome plating roll, but is not limited to this unless the surface shape or surface material adversely affects the inspection of the ink pattern. In addition, the inspection roll 200 is desirably an outer shape that can provide a circumferential length and a width that can have a surface area larger than the area of the transferred ink pattern, but is not limited thereto.

  The pattern inspection unit 202 according to the embodiment of the present invention irradiates the illumination light for inspection from above the inspection roll 200 by the illumination unit 203, and also by the inspection camera 204 installed above the inspection roll 200, The printing pattern formed on the inspection roll is imaged by rotating the inspection roll 200. The inspection camera 204 performs continuous imaging using, for example, a line sensor camera, but the imaging range of the camera in the width direction of the substrate is insufficient with respect to the width direction of the substrate, and all the ink on the inspection roll is captured in one imaging. If the pattern cannot be imaged, it may be selected as appropriate, such as imaging two or more cameras side by side.

  As for the defect detection size, since foreign matter such as dust of several tens of nm to several tens of μm is not lit, the detection capability corresponding to the defect is, for example, a camera capable of detecting 100 nm. The detection size may be appropriately selected in consideration of the product manufacturing environment, the defect size to be detected, the number of productions, etc.

    Using the captured image, a defect is detected by inspection using a pattern matching method or a comparative inspection method, and is recorded as data in the XY coordinate system. The data format is not particularly limited, but a file format (data file format, text file format, CSV file format, etc.) that can be recorded by a general personal computer is preferably used. The recorded contents include, for example, defect position information (X coordinate, Y coordinate), defect size, detection type (white defect, black defect, transmission defect, reflection defect), and the like.

  In the conventional method, a desired ink pattern is obtained by transferring ink from the anilox roll 104 to the relief plate 101 and further to the substrate 106. At this time, a chip, a protrusion, Alternatively, when there is an attached foreign matter or the like, there is a problem that a printing defect due to them occurs on all the substrates 106 to be printed. Therefore, before the ink pattern is formed on the substrate 106 by using the pattern inspection means 202 that includes the inspection roll 200 of the present invention and inspects defects generated in the ink pattern transferred onto the inspection roll 200, An ink pattern is transferred and formed on the inspection roll 200, and the ink pattern is inspected by the pattern inspection means 202, so that a chip or protrusion on the convex pattern of the plate 101 or an attached foreign matter is not printed on the substrate 106. It is possible to prevent defects in the ink pattern that occur due to the above.

  FIG. 5 shows the inspection roll cleaning means and the inspection roll drying means according to the embodiment of the present invention. The inspection roll cleaning means includes a liquid storage tank 302 installed so that the lower surface of the inspection roll is immersed in the cleaning liquid stored therein, and the surface of the inspection roll 200 in the liquid storage tank 302 as the roll rotates. This is an inspection roll cleaning apparatus 300 provided with a cleaning liquid supply nozzle 303 disposed so as to spray the cleaning liquid onto the surface of the inspection roll 200 at a place exposed from the cleaning liquid after being immersed in the stored cleaning liquid. The inspection roll drying means is an inspection roll drying nozzle 301, which is arranged so as to blow nitrogen or clean air on the cleaning liquid sprayed and adhered to the inspection roll 201. The surface of the inspection roll 200 is kept clean by the inspection roll cleaning device 300 and the inspection roll drying nozzle 301. In the present embodiment, the configuration of the liquid storage tank 302, the cleaning liquid supply nozzle 303, and the drying nozzle 304 is shown. However, the present invention is not limited to these, and means that can clean the surface of the inspection roll 200. If there is, it is not limited to the said structure, The structure without either the liquid storage layer 302 and the washing | cleaning liquid supply nozzle 303 may be sufficient, for example, scraping by a doctor, wiping by a cloth, etc. may be sufficient.

  FIG. 6 is a flowchart showing the overall operation of the relief printing apparatus of the present invention. After the start (S1), the inspection roller is washed and dried (S2). Next, after the ink is transferred to the relief printing plate by the anilox roll (S3), the pattern is transferred from the relief printing plate to the inspection roll (S4), and the transferred inspection roll pattern is inspected (S5). If the pattern is normal as a result of the pattern inspection (YES in S6), printing on the substrate is started (S7). If the pattern is not normal (NO in S6), printing on the substrate cannot be performed. After correcting the defective portion, the process proceeds to step (S2), and the inspection roll is cleaned and dried. When printing is performed on the substrate in step (S7) and the set inspection cycle is reached (in this case, the set inspection cycle refers to a cycle in which, for example, every 10 sheets are washed and dried, and the number of printed cycles is preset. (YES in S8), the process proceeds to step (S2) again, and the inspection roll is cleaned and dried. This is because, when printing is continued, foreign matter may adhere to the relief printing plate during the printing process, or chipping of the pattern may occur. This is to prevent pattern defects. If the set inspection cycle has not been reached (NO in S8), then it is checked whether the set number of prints has been reached (points to the number of prints and is set in advance), and if the set number of prints has been reached ( Printing is terminated in S9 (YES) (S10). On the other hand, if the set number of prints has not been reached (NO in S9), the process proceeds to step (S7) and printing is continued.

  In the above description, the case of producing a polymer organic EL display element has been exemplified. However, the present invention is not limited to this, and high-definition patterning formed by a relief printing method, for example, wiring printing with metal ink, printing of colored ink such as a color filter, etc. It is possible to apply to.

  As described above, according to the relief printing apparatus and the polymer organic EL display element manufacturing method of the present invention, ink pattern defects generated due to chippings, protrusions, and attached foreign matters on the projection pattern of the plate are confirmed before printing. Since it does not inspect directly on the substrate, the characteristics of the organic light-emitting layer may deteriorate due to the inspection light at the time of inspection or the inspection environment. The problem of being unable to play back can be solved. As a result, the yield can be improved.

DESCRIPTION OF SYMBOLS 100 ... Printing means 101 ... Letterpress 101a ... Surface layer 101b ... Base material layer 102 ... Plate cylinder 103 ... Ink pan 104 ... Anilox roll 105 ... Doctor 106 ... Substrate 107 ... Moving surface plate 107a ... Arrow 108 indicating the direction in which the moving surface plate moves ... Ink supply unit 200 ... Inspection roll 201 ... Inspection device 202 ... Pattern inspection means 203 ... Lighting means 204 ... Inspection camera 300 ... Inspection roll cleaning device 301 ... Inspection roll drying nozzle 302 ... Storage tank 303 ... Cleaning liquid supply nozzle 400 ... Support base Stand

Claims (6)

A relief printing apparatus for printing a pattern on a substrate to be printed (hereinafter referred to as a substrate) using a relief plate,
The relief printing apparatus includes a printing unit and a pattern inspection unit.
The printing means includes the relief plate, a plate cylinder on which the relief plate is mounted, an ink supply unit that supplies ink to the surface of the relief plate, and a moving surface plate that places and conveys the substrate.
The letterpress printing apparatus, wherein the pattern inspection means includes an inspection roll provided in a moving mechanism of the moving surface plate, and an inspection apparatus that inspects a pattern printed on the inspection roll.   2. The inspection apparatus includes: illumination means for irradiating the inspection roll with illumination light for inspection; and an inspection camera for imaging a pattern printed on the inspection roll. Letterpress printing equipment.   3. The relief printing apparatus according to claim 1, wherein printing on the substrate is started when the pattern printed on the inspection roll is determined to be normal by the pattern inspection means.   The letterpress printing apparatus according to any one of claims 1 to 3, wherein the pattern inspection by the pattern inspection unit is performed every preset number of printed inspection cycles.   5. The apparatus according to claim 1, further comprising: a cleaning unit that cleans the pattern printed on the inspection roll with a cleaning liquid; and a drying unit that dries the cleaning liquid attached on the inspection roll. Letterpress printing equipment.   A polymer organic EL display element manufacturing method comprising manufacturing a polymer organic EL display element using the relief printing apparatus according to claim 1.

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