JP2012204137A - Method for manufacturing polymer el element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a polymer EL element high in quality and less in foreign matters.SOLUTION: A polymer EL element holds an organic light emitting layer, which includes a polymer light emitting material, between two electrodes formed on a base material, at least one of the two electrodes being transparent or translucent. In a method for manufacturing the polymer EL element, the organic light emitting layer is formed by coating or printing using a roll coat method, an ink doctor is used for the coating or printing, and the ink doctor is a rubber roll and an air knife.

Description

  The present invention relates to a method for producing a high-quality polymer EL device.

  FIG. 1 is a cross-sectional view showing an example of a polymer EL element. The polymer EL element is composed of a glass substrate 1, at least one of transparent or translucent electrode layers 2 and 4, and an organic light emitting layer 3 sandwiched between both electrodes.

  In recent years, attempts have been made to use a known printing method that is excellent in mass productivity and can reduce the manufacturing cost in forming a fine thin film pattern. In particular, in the display field, in order to cope with an increase in screen size and cost, studies are being made to form a functional thin film by a printing method.

  As specific printing methods, offset printing, gravure printing, gravure offset printing, letterpress printing, and the like are being studied.

  Among these various printing methods, the resin relief printing method uses a resin relief printing plate, an ink roll engraved with fine recesses (called cells) on the surface called an anilox roll, and solvent-dried ink. It has been widely used for printed materials such as wrapping paper. This resin relief printing method is particularly suitable for forming a thin and stable printing layer having a film thickness of about 0.01 to 0.2 μm. In addition, since the resin relief printing method can be printed at a very low printing pressure called kiss touch, it can be applied to a glass substrate or a substrate on which a transparent electrode or the like whose characteristics are easily destroyed by applying high pressure is formed. It is also suitable for printing, and is a printing method particularly suitable for pattern formation of electronic parts such as displays.

  Next, a commonly used relief printing apparatus will be described with reference to FIG. In this relief printing apparatus, an anilox roll 201 having a cell for supplying ink to the plate surface of the relief plate 204, an ink chamber 208 for supplying ink to the anilox roll, and a relief cushion 204 for pattern formation via an under-cushion cushion 203 are provided. A rotary plate cylinder 205 to be mounted, a substrate surface plate 206 on which a substrate 207 to be printed is placed, and a doctor blade 202 that performs doctoring to scrape off ink are configured.

  Next, the flow of printing when using the printing machine of FIG. 2 will be described. First, after a substrate to be printed is placed on the substrate surface plate 206, it moves to a position directly below the plate cylinder 205. When the substrate surface plate 206 moves, the plate cylinder 205 rotates synchronously with the operation of the substrate surface plate 206, and ink is supplied to the relief plate 204 from the anilox roll 201 operating at the same speed as the plate cylinder 205. After the ink is supplied to the relief plate 204, the relief-form ink is quickly transferred to the printing substrate 207 and the printing operation is completed.

  Here, the doctor blade 202 is generally pushed to the anilox roll with a pressure of about 20 kPa in order to uniformly push the ink into the anilox roll cell by scraping off excess ink from the ink applied on the anilox roll 201. Hit. For this reason, both the anilox roll and the doctor blade are worn, and there is a problem that the scraped portion is mixed into the ink.

  Since an anilox roll and a doctor blade are generally made of a metal oxide or a resin, they are mixed into the ink as foreign matters.

  If it is a general printed matter in the conventional resin letterpress printing method, it will not be a big problem, but in the printing for electronic materials for the purpose of fine patterning of functional thin films such as organic semiconductor thin films and organic EL thin films, scraped foreign matter If the product is defective due to this, or if the foreign material is metal, problems such as short-circuiting due to electrical conduction may occur.

  As described above, as a means for scraping off the ink on the anilox roll, a doctor blade is mainly used. However, as shown in Patent Document 1, a doctor roll technique in which rubber or the like is processed on the roll is also used. ing. By using the doctor roll method, the generation of foreign matter as generated by the doctor blade method can be suppressed to a low level, but the scratching property is inferior to that of the doctor blade, and sufficient ink is applied to the anilox roll cell. It was impossible to push in, and it was difficult to pattern fine thin films with high quality.

JP 2001-083495 A

  As described above, the conventional resin relief printing method is a printing method having excellent characteristics, but to obtain a high-quality printed material, such as doctoring and reducing the occurrence of foreign matter affecting the printed material, It did not meet the required characteristics.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for producing a polymer EL element that solves such problems and has high quality and few foreign substances.

The present invention has been made in view of the above problems, and the invention according to claim 1 is a method of manufacturing a polymer EL element,
In a polymer EL device in which an organic light emitting layer containing a polymer light emitting material is sandwiched between two electrodes, at least one of which is transparent or translucent, formed on a substrate, the organic light emitting layer is coated by a roll coating method Or it is a manufacturing method of the polymer EL element characterized by forming by printing.

  The invention according to claim 2 is the method for producing a polymer EL element according to claim 1, wherein an ink doctor is used for the coating or printing, and the ink doctor is a rubber roll and an air knife.

  The invention according to claim 3 is the method for producing a polymer EL element according to claim 1, wherein the plate used for the coating or printing is made of resin.

  According to the manufacturing method of the present invention, it is possible to easily form a printed pattern having a uniform film thickness without unevenness, and to reduce the generation of foreign matters that impair the function of the thin film.

The figure which shows an example of a polymer EL element in a cross section. The figure for demonstrating the outline of the relief printing apparatus which has a doctor roll generally used. The figure for demonstrating the ink supply part in a resin relief printing press. The figure which shows having provided the air knife in the ink supply part of FIG. The figure which showed the ink supply part in detail.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  An embodiment of the present invention will be described focusing on the ink supply unit 110 in the resin relief printing press shown in FIG. The resin relief printing press applied to the method for producing the polymer EL element of the present invention shown in FIG. 3 supplies a cylinder type copper plate 105 on which a relief forming plate 104 for pattern formation is mounted and ink in contact with the relief plate 104. An ink supply unit 110 having a cylindrical anilox roll 101, an ink chamber 108 for supplying ink to the anilox roll, and a cylindrical doctor roll 102 for scraping off excess ink on the anilox roll 101, and a substrate are placed thereon The printing apparatus includes a substrate surface plate 106.

  In addition, as shown in FIG. 4, it is desirable to provide an air knife 109 so that air is ejected toward a portion where excess ink on the anilox roll 101 is scraped off by the doctor roll 102. FIG. 5 is a detailed view of the ink supply unit 110 of FIG. Here, the air knife 109 is installed so as to eject air toward both ends of the anilox roll 101, and further, air is ejected from the side after the excess ink is scraped off by the doctor roll 102. Installed. By installing in this way, it is possible to prevent surplus ink from flowing around the anilox roll 101 after surplus ink is scraped off along the end of the doctor roll 102.

  As a means for supplying ink, in addition to the ink chamber, a drop type coater such as a fountain roll, a slit coater, a die coater, a cap coater, or a combination thereof may be used.

  As an anilox roll 101 that can be used for resin relief printing according to the present invention, a chromium oxide film formed by plasma spraying chromium oxide on a core roll made of SUS material or the like was patterned by laser engraving. Either a ceramic roll or a chrome roll in which a resin is applied after copper plating is applied to the core roll, followed by laser patterning, followed by corrosion treatment, and chrome plating on the resulting pattern can be used.

  Moreover, as a pattern formed on an anilocle roll, any patterns, such as a helical pattern, FM (frequency mosaic) pattern, a honeycomb pattern, a diamond pattern, and an ART pattern (dot pattern), can be used.

  These patterns are preferably formed at an appropriate angle in order to prevent moire. After these patterns are formed, the surface of the anilox roll 101 is desirably polished in order to prevent scratching the doctor roll 102 side. Specifically, it is desirable that the anilox roll pattern is polished so as to eliminate protrusions of 4 μm or more.

  As a mechanism for rotating the anilox roll 101, it is desirable to perform direct drive with a servo motor capable of controlling rotation with high accuracy because uneven rotation speed greatly affects printed matter. Further, when a speed reduction mechanism is used to obtain a necessary torque, it is desirable to use a backlashless mechanism.

  Next, as a doctor roll 102 that can be used, a core roll made of SUS material, etc., nitrile rubber, silicone rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprene rubber, butyl rubber, acrylonitrile rubber, ethylene propylene A rubber, urethane rubber, or the like may be wound around the rubber roller, or a PFA heat shrinkable tube wound around these rubber rollers may be used. These rubber materials are selected from the resistance to the solvent used as the ink.

  The surfaces of these rubber rolls preferably have an arithmetic average roughness Ra of 0.1 μm or less and a maximum height Rz of 1 μm or less. By satisfying these conditions, a low dust generation and smooth doctoring surface can be obtained.

  Next, as the hardness of the doctor roll 102 which can be used, any can be used in the range of 30 degrees-70 degrees in JIS-A hardness.

  As the mechanism for rotating the doctor roll 102, it is desirable to use a servo motor that can control the rotation with high accuracy and to perform the direct drive because uneven rotation speed has a large effect on the printed matter, and is synchronized with the rotation of the anilox roll. It is desirable to have a system that can be controlled in a rotatable manner.

  Next, the air knife 109 that can be used is designed so that the sprayed air does not diffuse but keeps a constant pressure from the hole and goes straight. In addition, the air knife is designed to be adjustable to any angle so that the air injection angle can be changed.

  Next, the operation when this printing machine is used will be described. After placing the glass substrate 107 on the substrate surface plate 106, a printing operation is started by a print start instruction. During this time, ink is supplied onto the anilox roll 101 and doctoring is continuously performed, so that a smooth doctored surface is always held. Next, after the substrate surface plate moves just below the plate cylinder, the ink is transferred onto the plate from the anilox roll 101, and then to the glass substrate 107 placed on the substrate surface plate 106 that moves in synchronization with the plate cylinder rotation. Printing is performed.

  The speed at which the ink is transferred from the anilox roll 101 onto the plate may be equal to the doctoring speed. However, when the doctoring speed is low, it takes time to transfer, so the transfer speed may be increased. However, when the transfer speed is increased, it is necessary to adjust so that the doctoring surface obtained under the doctoring condition of the present invention is transferred to the plate. By performing the above operation, a high-quality printed material can be obtained.

Example 1
Examples of the present invention will be described. In addition, this invention is not limited to an Example, The improvement, deformation | transformation, etc. in the range which can achieve this invention do not deviate from the meaning of this invention.

  In this embodiment, an example in which a polymer type organic light emitting material is printed on glass is shown.

  As the printing machine, the printing machine shown in FIG. 4 is used.

  A chrome roll was used as the anilox roll used in this example. The pattern formed on the roll is a diamond pattern in which square cells each having a side of 65 μm are formed at a pitch of 72.5 μm, and these patterns are formed inclined by 60 ° from the horizontal line of the roll.

Next, as a doctor roll to be used, urethane rubber having a hardness of JIS-A 50 degrees was wound on a SUS core and processed into a columnar shape so as to be within 0.5 mm with respect to the target diameter. After winding the PFA heat shrinkable tube on the processed urethane rubber roll, polishing was carried out so that Ra was 0.05 μm and Rz was 1 μm.

  The doctor roll was installed in the form of pressing 50 μm against the above anilox roll. The installed anilox roll and doctor roll are each driven by a servo motor.

  Next, the plate material used will be described.

  A black oil-based dye was applied to the surface of a SUS304 plate having a thickness of 0.2 mm as a reflection suppressing layer by a die coating method so as to have a thickness of 1.5 μm. A negative photosensitive resin mainly composed of polyamide was applied on the surface of this laminate so that the total thickness was 0.1 mm, and used as a base of the plate.

  After that, a negative pattern having a pattern on the stripe (effective area opening 106 μm × 50 mm, non-opening space 392 μm × 50 mm, total effective number of 64 lines as a group, 1 cm horizontally, 2 cm vertically A proximity gap of 50 μm was opened using a chromium mask of 6 × 2), and exposure was performed with an aligner. After the exposure, development was performed while pouring warm water to form a relief plate having a convex portion height of 90 μm, a convex portion line width of 104 μm, and a space of 392 μm. The prepared relief plate was attached to the plate cylinder of a printing machine using a printing cushion tape having a thickness of 0.5 mm.

  Next, the luminescent ink will be described.

  An organic light-emitting ink was prepared by dissolving a polyphenylene vinylene derivative, which is a high-molecular organic light-emitting material, in anisole so as to have a concentration of 2%. When the viscosity of the prepared ink was measured, it was 60 mPa.s. s, and the surface tension was 34 mN / m. Thereafter, the ink was put into the ink chamber of the printing machine.

  Printing was performed on soda glass having a size of 300 mm square and t = 0.7 mm using the above apparatus, plate, and luminescent material ink. Printing was performed at a tact time of 60 sec (seconds), the doctoring speed was 5 mm / sec, and the printing speed was 100 mm / sec.

(Comparative Example 1)
In Comparative Example 1, printing was performed in the same manner as in Example 1 except that the doctoring speed in Example 1 was 100 mm / sec.

(Comparative Example 2)
In Comparative Example 2, a doctor blade was used without using the doctor roll in Example 1, and the doctoring speed was 100 mm / sec. Otherwise, printing was performed in the same manner as in Example 1.

  The following evaluation was performed about the board | substrate with which the organic light emitting layer obtained in Example 1 and Comparative Examples 1 and 2 was formed. As evaluation items, PL emission intensity in-plane variation evaluation in a state where the printed matter was caused to emit PL light, evaluation of unevenness by visual inspection, and foreign matter evaluation in one panel were performed.

  The results of evaluation are shown in Table 1.

  In Example 1, the in-plane emission intensity variation was as small as 8%, and no specific unevenness was observed. Furthermore, the number of foreign matters was as small as 13 pieces.

  In Comparative Example 1, although the number of foreign matters was relatively good, oblique stripe unevenness was confirmed throughout, and the emission intensity variation was very large.

  In Comparative Example 2, unevenness and light emission intensity variation were the same as in Example 1, but the number of foreign matters was increased.

  From the above results, Example 1 was evaluated better than Comparative Examples 1 and 2. Printing could be performed by coating or printing by a roll coating method, and the ink doctor was a rubber roll and an air knife, and the plate was made of resin.

  As described above, according to the method for producing a polymer EL element according to the present invention, a high-quality polymer EL element can be easily formed with a uniform film thickness with little in-plane variation and no unevenness. Can be manufactured.

DESCRIPTION OF SYMBOLS 1 ... Glass substrate 2 ... Electrode layer 3 ... Organic light emitting layer 4 ... Electrode layer 101 ... Anilox roll 102 ... Doctor roll 103 ... Underlay cushion 104 ... Letterpress 105 ... Plate cylinder 106 ... Substrate surface plate 107 ... Print substrate 108 ... Ink chamber 109 ... Air knife 110 ... Ink supply unit 201 ... Anilox roll 202 ... Doctor blade 203 ... Underside plate cushion 204 ... Letter plate 205 ... Plate cylinder 206 ... Substrate surface plate 207 ... Printed substrate 208 ... Ink chamber 209 ... Ink supply unit 210 ... Ink Supply section

Claims (3)

A method for producing a polymer EL device, comprising:
In a polymer EL device in which an organic light emitting layer containing a polymer light emitting material is sandwiched between two electrodes, at least one of which is transparent or translucent, formed on a substrate, the organic light emitting layer is coated by a roll coating method Alternatively, a method for producing a polymer EL element, which is formed by printing.   The method for producing a polymer EL device according to claim 1, wherein an ink doctor is used for the coating or printing, and the ink doctor is a rubber roll and an air knife.   2. The method for producing a polymer EL element according to claim 1, wherein the plate used for the coating or printing is made of a resin.

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