JP2008135326A - Manufacturing method of high definition display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a high definition display in which problems such as collapse of pattern shape, membrane thickness fluctuations or the like due to increase or decrease of ink transition amount do not occur, and a display having a high definition pattern can be formed in an accurate size pattern shape and with superior reproducibility. <P>SOLUTION: The manufacturing method of the high definition display has a process in which printing of the high definition patterns of 100 to 210 ppi on a printed body 7 is carried out by a relief printing method, using an electronic material ink 4a, and in the manufacturing method of the high definition display, the line number of anilox rolls 5 used in the relief printing is arranged to be 150 to 600 lines/inch. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

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

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

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

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

  The letterpress printing method includes, for example, a printing machine as shown in FIG. 2 as a circular pressure letterpress printing machine. As shown in the figure, an ink tank 2 and an ink discharge part 3 (chamber) which is an ink supply part, and an anilox roll 5 rotating in the direction of the arrow (metal or resin hard roll, or hard roll having moderate elasticity) And a plate cylinder 6 that rotates in the direction of the arrow so that the printing relief plate 1a can be mounted on the peripheral surface. Below the plate cylinder 6, a printing medium fixing surface plate 8 that repeatedly moves in the horizontal direction (arrow direction) is provided, and the printing medium 7 is mounted and fixed on the surface plate 8.

  Ink is accommodated in the ink tank 2, and ink is sent from the ink tank 2 to the ink discharge unit 3. The anilox roll 5 is close to the ink discharge unit 4 and rotates in contact with the printing relief plate of the plate cylinder 6.

  As the anilox roll 5 rotates, the ink 4 a discharged from the ink discharge unit 3 to the peripheral surface of the anilox roll 5 is scraped to a uniform film thickness by the doctor 9 or the like, and the uniform film thickness is formed on the peripheral surface of the anilox roll 5. Transfer as an ink film. Thereafter, the ink 4a on the circumferential surface of the anilox roll 5 is transferred to the top surface of the convex portion (the relief plate 1b) of the printing relief plate 1a attached to the plate cylinder 6 with a uniform film thickness.

  Furthermore, the printing body 7 (printing substrate) on the printing body fixing surface plate 8 is adjusted by a position adjusting mechanism that adjusts the phase position between the convex pattern of the convex portion 1b of the printing relief plate 1a and the printing body 7. While adjusting the phase position, as shown in FIG. 2, it moves horizontally to the printing start position in the left direction of the drawing.

  After that, the printing substrate fixing surface plate 8 matches the rotational speed of the plate cylinder 6 while bringing the convex portion 1b of the printing relief plate 1a of the printing cylinder 6 into contact with the surface of the printing substrate 7 with a predetermined printing pressure. Then, it moves horizontally in the left direction of the drawing, and a convex pattern of ink 4a on the top surface of the convex portion 1b of the printing relief plate 1a is printed on the surface of the printing medium 7.

  After the printing, the printed material 7 is removed from the printed material fixed surface plate 8, and then the next printed material 7 is mounted and fixed on the printed material fixed surface plate 8. Printing is performed by repeating this operation.

  Further, although not shown in the figure, a circular pressure type letterpress printing machine includes a printing machine using a cylindrical rotating blanket cylinder and a flat pressure platen fixed at a fixed position. This is a flat plate-fixing platen for placing and fixing a flat printing relief plate horizontally, and a flat printing substrate-fixing platen for placing and fixing a printing material (printing substrate) horizontally. (Pressure platen), an ink supply roller for circumferentially moving (rolling) the upper surface of the printing relief plate placed and fixed on the plate fixing platen, and depositing ink on the top surface, and an ink supply roller During the standby, the upper surface of the printing relief printing plate is circumferentially moved (rolled) to transfer the ink adhering to the top surface to the blanket surface made of rubber, and the ink that has been rolled and transferred to the blanket surface. A blanket cylinder is provided that transfers and prints on a printed body (printing substrate) placed and fixed on a fixed body for printing.

  On the other hand, it is known that viscous (or thixotropic) ink or liquid ink (ink liquid) for coating in letterpress printing has optimum viscosity and surface tension. In general, a viscosity modifier such as a thickener, a surfactant for adjusting the surface tension, or the like is added.

  When printing an electronic material, its solubility may be limited, impurities may be disliked, and ink physical properties may be greatly limited.

  In particular, when an organic light-emitting material is printed by a printing method to form a film, the organic light-emitting material is printed by being dispersed or dissolved in a solvent (binder resin as necessary) such as water, alcohol, or an organic solvent. Ink is used as an ink liquid for coating.

  When an organic light emitting material is formed into a pattern and driven as an element, it is said that the durability of the element is better when the film formed of the organic light emitting material has a higher purity. Residual thickeners cannot be added because they cause a decrease in purity. For this reason as well, it is possible to adjust the ink composition of the organic light-emitting material to obtain the ink transferability of the printed matter and the stability of the pattern shape. The range of various physical properties is limited.

  Furthermore, when pattern-printing the above organic light emitting material to make a display, when the definition is low (when the definition is less than 100 ppi), the width of the convex portion of the plate is 40 μm or more, and the height of the plate is Even if it is about 100 μm, the strength of the convex portion can be kept sufficiently. However, in the case of a high-definition pattern of 100 ppi or more, the width of the convex portion of the plate is 40 μm or less. In order to maintain the shape of the convex portion of the plate, it is necessary to reduce the height to about 50 μm.

For this reason, ink enters the recess and it becomes difficult to print a normal pattern.
JP 2001-93668 A Japanese Patent Laid-Open No. 2001-155858 JP 2001-155861 A

  The present invention solves the above-mentioned problems, and does not cause various problems such as a collapse of the pattern shape and a film thickness variation due to a decrease or an increase in the amount of transferred ink. An object of the present invention is to provide a method for manufacturing a high-definition display that can be formed with good reproducibility by shape.

  The invention according to claim 1 is a method for manufacturing a high-definition display having a step of printing a high-definition pattern of 100 to 210 ppi on a printing material using an electronic material ink by a letterpress printing method. A high-definition display manufacturing method characterized in that the number of lines of anilox roll used for printing is 150 to 600 lines / inch.

  The invention according to claim 2 is characterized in that when the viscosity of the electronic material ink is 10 to 50 mPa · s, the number of lines of the anilox roll is set to 300 to 600 lines / inch. The manufacturing method according to claim 1 of the high-definition display.

  The invention according to claim 3 is characterized in that when the viscosity of the electronic material ink is 50 to 150 mPa · s, the number of lines of the anilox roll is set to 150 to 400 lines / inch. It is a manufacturing method of the high-definition display as described.

  According to the production method of the present invention, since the number of lines of the anilox roll is appropriately set, ink does not flow into the low-order part and the concave part which are non-image parts other than the top face of the convex part of the printing relief printing plate. . Therefore, it is possible to form a display having a high-definition pattern with an accurate sized pattern shape with good reproducibility without causing problems such as collapse of the pattern shape and film thickness fluctuation due to decrease or increase in the amount of transferred ink. Can do.

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

  FIG. 1 is a side sectional view of a relief printing plate for producing an organic EL device according to an embodiment of the present invention, 10a is a relief base substrate layer, and 10b is a relief on the base substrate layer 10a. It is a shape part formation material layer (it may only be called a convex part hereafter).

  In addition to rubbers such as nitrile rubber, silicone rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprene rubber, butyl rubber, acrylonitrile rubber, ethylene propylene rubber, and urethane rubber, the convex portion forming material layer includes polyethylene, polystyrene, Synthetic resins such as polybutadiene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyamide, polyether sulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, and polyvinyl alcohol, copolymers thereof, and natural polymers such as cellulose Can be used.

  In particular, a material containing a water-soluble polymer as a main component has high resistance to an organic solvent that constitutes a solution or dispersion of an organic light-emitting material that is a component of electronic material ink.

  Here, for example, as an electronic material ink of an organic light emitting material, which is one of electronic materials, there is an advantage that the lower the boiling point, the easier the drying process becomes. However, considering the printing process time, the boiling point is too low. When a low solvent is used, the ink is dried at the convex portions. Therefore, it is preferable to appropriately mix a solvent having a boiling point of 130 ° C. or higher with the ink to prevent the ink from drying.

  Examples of the solvent having a boiling point of 130 ° C. or higher include 2,3-dimethylanisole, 2,5-dimethylanisole, 2,6-dimethylanisole, trimethylanisole, tetralin, methyl benzoate, ethyl benzoate, cyclohexylbenzene, n- One or more kinds can be selected from amylbenzene, tert-amylbenzene, diphenyl ether, and dimethyl sulfoxide.

  Organic light-emitting materials include polymers in which low-molecular fluorescent dyes are dissolved in polymers such as polystyrene, polymethyl methacrylate, and polyvinyl carbazole, and polymers such as polyphenylene vinylene derivatives (PPV) and polyalkylfluorene derivatives (PAF). A light emitter is used. These high-molecular organic light-emitting materials (light-emitting materials for polymer EL devices) can be dissolved or stably dispersed in a solvent, and can be formed into a film by a coating method or a printing method when converted into an ink. Compared to the production of an organic EL element using a material, there is an advantage that film formation under atmospheric pressure is possible and the equipment cost is low.

  As the relief plate S, the materials described above can be used, but a commercially available flexographic plate or resin relief plate can be used.

  The printing relief plate of the present invention can be printed by being mounted on a printing press using a relief printing method (a method of printing using a printing relief plate), for example, a circular pressure relief printing press or a circular pressure relief printing offset. It can be mounted on a printing machine and printed.

The production method of the present invention includes a step of printing a high-definition pattern of 100 to 210 ppi on a printing medium using the above relief printing method and electronic material ink. Here, the number of anilox rolls used for letterpress printing needs to be 150 to 600 lines / inch. Outside this range, various problems such as collapse of the pattern shape and film thickness variation due to decrease or increase in the amount of ink transfer occur.
Moreover, when the viscosity of electronic material ink is 10-50 mPa * s, it is preferable to set the number of lines of an anilox roll to 300-600 line / inch. More preferably, it is 300 to 400 lines / inch. On the other hand, when the viscosity of the electronic material ink is 50 to 150 mPa · s, it is preferable to set the number of lines of the anilox roll to 150 to 400 lines / inch. More preferably, it is 250 to 400 lines / inch. In the present invention, the viscosity of the ink is a value measured at 25 ° C., and a rheometer is used as the viscosity measuring instrument.

  EXAMPLES The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

<Example 1> Printing of 180 ppi pattern (Preparation of electronic material ink for forming organic light emitting layer)
The polymeric fluorescent substance was dissolved in a solvent so as to have a concentration of 2.0% by weight to prepare an electronic material ink liquid 4a for forming an organic light emitting layer. The viscosity of the ink was 38.3 mPa · s. Here, the polymeric fluorescent substance refers to a light emitting material made of a poly (paraphenylene vinylene) derivative. The ink solvent composition was 88% by weight of xylene (boiling point 139 ° C.) and 10% by weight of tetralin (boiling point 202 ° C.).

(Preparation of printed material)
Spin on the ITO film surface of a substrate for transparent electrode production (manufactured by Geomatic Co., Ltd.) in which an ITO film with a surface resistivity of 15Ω is formed in a circuit pattern on a 150 mm square, 0.4 mm thick glass substrate. Using a coater, poly (3,4) ethylenedioxythiophene / polystyrene sulfonic acid (PEDOT / PSS) was deposited to a thickness of 100 nm as a hole transport layer. Further, the PEDOT / PSS thin film thus formed was dried at 180 ° C. under reduced pressure for 1 hour, thereby producing a substrate 7 (printing substrate).

(Preparation of printing letterpress)
The base substrate layer 10a is obtained by spin-coating a polyethylene terephthalate (PET) substrate having a thickness of 0.3 mm and a photosensitive water-soluble polymer (water-soluble resin) heated at 150 ° C. as a convex portion 10b. A layer having a thickness of 0.1 μm was formed by the method, and the formation layer of the convex portion 10b was laminated.

(Forming letterpress patterns for printing)
The plate was formed with convex portions and concave portions by L / S = 20/121 μm by photolithography. (Equivalent to 180 ppi)

(Printing of light-emitting layer forming coating ink liquid by printing letterpress S)
First, a printing relief plate as shown in FIG. 1 is mounted and fixed on the peripheral surface of the plate cylinder 6 of a pressure relief printing machine (see FIG. 2) by the relief printing method, and the substrate 7 (printing substrate) is attached to the substrate. It was placed and fixed on the printing plate fixing surface plate 8.

  Then, the anilox roll 5 having a number of lines of 500 lines / inch and the plate cylinder 6 are rotated, and the electronic material ink 4a for forming the light emitting layer is supplied to the peripheral surface of the anilox roll 5 (ink supply roller) as a uniform film, The ink liquid 4a was supplied to the top surface of the convex portion of the relief printing plate through the anilox roll 5. Thereafter, the printed electronic material ink 4a was printed on the top surface in alignment with the ITO film pattern on the printed film 7 (printing substrate) side of the ITO film pattern.

  The printed material 7 (printed substrate) after printing is dried in an environment of 150 ° C. for 5 hours to dry the electronic material ink 4a, and then the calcium 7 nm is formed on the light emitting layer by the ink liquid 4a. Then, 80 nm of aluminum was laminated to form an organic EL element having a cathode.

<Comparative Example 1>
In Example 1, an experiment similar to that in Example 1 was performed, except that an anilox roll having a line number of 120 lines / inch was used.

<Comparison result>
When the organic EL device produced in Example 1 was applied with a voltage through the ITO film and the light emission state was confirmed, the film thickness of the light emitting layer was uniform and no light emission unevenness was observed. When the organic EL element produced by Example 1 applied a voltage through the ITO film | membrane and confirmed the light emission state, the light emission nonuniformity by the nonuniform thickness of the light emitting layer was seen. This is because the ink has entered the adjacent pixels and the film thickness distribution has deteriorated due to excessive ink on the plate. In normal printing (Example 1), the film thickness was 80 nm, but the average value of the film thickness in Comparative Example 2 was 130 nm and was not uniform.

<Example 2> Printing of 180 ppi pattern The type of polymeric fluorescent substance in Example 1 was changed to obtain an ink having a viscosity of 87 mPa · s.
The number of anilox rolls in Example 1 was 150 lines / inch. Otherwise, the same procedure as in Example 1 was performed.

<Comparative example 2>
In Example 2, the number of anilox rolls was 800 lines / inch. Otherwise, the same procedure as in Example 2 was performed.

<Comparison result>
When the organic EL device produced in Example 2 was applied with a voltage through the ITO film and the light emission state was confirmed, the film thickness of the light emitting layer was uniform and no light emission unevenness was observed. When the organic EL device produced in Example 2 was applied with a voltage through the ITO film and the light emitting state was confirmed, light emission unevenness and short-circuit due to the non-uniform thickness of the light emitting layer were observed. This is because the film thickness has become extremely thin due to insufficient transfer of ink to the plate. In normal printing (Example 2), the film thickness was 80 nm, but the film thickness of Comparative Example 2 was 20 nm and was not uniform.

  According to the manufacturing method of the present invention, a display having a high-definition pattern can be formed with an accurate size pattern shape without causing problems such as collapse of the pattern shape, film thickness fluctuation due to decrease or increase in the amount of ink transfer. Thus, it can be formed with good reproducibility.

It is a general | schematic side sectional view of the relief printing plate of this invention. It is a schematic diagram of the printing machine in a relief printing method.

Explanation of symbols

4a Ink 5 Anilox roll 6 Plate cylinder 7 Printed body 10a Base substrate layer 10b Convex part forming material layer S Letterpress for printing

Claims (3)

  A method of manufacturing a high-definition display having a step of printing a high-definition pattern of 100 to 210 ppi on a substrate using electronic material ink by a letterpress printing method, wherein the number of anilox rolls used for letterpress printing is determined. 150 to 600 lines / inch, a method for manufacturing a high-definition display.   2. The high-definition display according to claim 1, wherein when the viscosity of the electronic material ink is 10 to 50 mPa · s, the number of lines of the anilox roll is set to 300 to 600 lines / inch. Manufacturing method.   2. The method of manufacturing a high-definition display according to claim 1, wherein when the viscosity of the electronic material ink is 50 to 150 mPa · s, the number of lines of the anilox roll is set to 150 to 400 lines / inch.

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