JP4922989B2 - Coating device - Google Patents

Description

  The present invention relates to a coating apparatus, and more particularly to a coating apparatus that prints and applies a coating liquid onto a substrate placed on a stage.

  An organic EL device is actively used for illumination and display. When manufacturing these organic EL devices, an organic EL material, a hole transport material, an electron transport material, or the like is applied to the substrate in a relatively large-sized thin film, or red, green, blue, and white. It is necessary to coat organic EL materials such as light emission in fine stripes. By repeating these coating operations and stacking the layers, a light emitting layer, a hole transport layer, an electron transport layer, and the like of the organic EL device are formed.

  As an organic EL material used as a material of a light emitting layer, there are a high molecular material and a low molecular material formed into a thin film by coating (hereinafter simply referred to as an organic EL material). And the manufacturing method which forms the thin film of organic EL material on a board | substrate using various printing methods and a special coating method is tried. In general, in such a manufacturing method, an aromatic solvent is used as a main solvent for forming an organic EL material into an ink.

For example, a method of printing and applying an organic EL material using a flexographic plate adopting an anilox roller method for inking is conceivable. However, when inking into the flexographic plate using the anilox roller method, the organic EL material to be printed and applied changes drastically with time, so that the dried organic EL material may remain in the cells (recesses) of the anilox roller. As a result, the coating amount of the organic EL material to be printed and coated becomes unstable, leading to a reduction in quality. In order to prevent such organic EL material from remaining, a printing apparatus that inks a flexographic plate using a flat roller having a smooth circumferential surface is disclosed (for example, see Patent Document 1). In the printing apparatus disclosed in Patent Document 1, an organic EL material is printed on a substrate using a printing plate wound around a plate cylinder to form a thin film of the organic EL material.
JP 2008-6705 A

  Here, the thin film of the organic EL material is required to have a uniform film thickness in order to prevent light emission unevenness and electric field concentration. In order to improve such uniformity, the printing apparatus disclosed in Patent Document 1 described above requires low viscosity (for example, several tens of cP (centipoise)) in order to perform leveling for smoothing and uniforming the organic EL material. The following organic EL material must be used.

  However, when the organic EL material is printed and applied by the printing apparatus disclosed in Patent Document 1, there are two processes in which the organic EL material is transferred from the flat roller to the flexographic plate and from the flexographic plate to the substrate. In the printing apparatus, at the stage of transferring the organic EL material from the flat roller to the flexographic plate, the amount of the organic EL material held tends to increase toward the back of the flexographic plate. Further, in the printing apparatus, at the stage of transferring the organic EL material from the flexographic plate to the substrate, the transfer amount of the organic EL material tends to increase toward the rear of the substrate to be printed and applied. This can be attributed to a phenomenon in which the organic EL material is pushed backward when the low-viscosity organic EL material is contact-transferred. For this reason, in the said printing apparatus, since the nonuniformity arises in the transfer amount of the organic EL material printed and applied to the substrate, it becomes difficult to form a thin film with high film thickness uniformity.

  Therefore, an object of the present invention is to provide a coating apparatus that improves the film thickness uniformity when a coating liquid containing an organic EL material is applied by printing.

In order to achieve the above object, the present invention has the following features.
1st invention is the coating device which print-coats the coating liquid containing organic EL material on a board | substrate. The coating apparatus includes a mounting table, a plate cylinder, a printing plate, a coating liquid supply unit, and a relative movement unit. The mounting table places the substrate on the upper surface thereof. The printing plate is wound around the outer peripheral surface of the plate cylinder, and a convex pattern corresponding to the pattern to be printed and applied on the surface thereof and a dot-like uneven surface holding the coating liquid on the upper surface of the convex pattern are formed. The The coating liquid supply unit supplies the coating liquid to the surface of the printing plate. The relative movement means moves the mounting table and the plate cylinder relative to each other while rotating the plate cylinder about the axis while the substrate upper surface and the printing plate are opposed to each other in close proximity or in contact with each other. The concavo-convex surface is formed so that the holding amount for holding the coating liquid gradually decreases with respect to the printing direction of the printing plate that the relative moving means sequentially faces the upper surface of the substrate.

  In a second aspect based on the first aspect, the concavo-convex surface has a plurality of convex portions arranged in a dot pattern and concave portions formed around the convex portions. The concavo-convex surface is formed so that the holding amount for holding the coating liquid is gradually reduced by gradually reducing the size of the concave portion with respect to the printing direction.

  In a third aspect based on the second aspect, the uneven surface gradually decreases the size of the concave portion with respect to the printing direction by gradually increasing the size of the convex portion with respect to the printing direction.

  In a fourth aspect based on the second aspect, the concavo-convex surface gradually decreases the size of the concave portions with respect to the printing direction by gradually shortening the arrangement interval of the convex portions with respect to the printing direction.

  In a fifth aspect based on the first aspect or the second aspect, the concavo-convex surface has a plurality of convex portions arranged in a dot pattern and concave portions formed around the convex portions. The concavo-convex surface is formed such that the holding amount for holding the coating liquid gradually decreases by gradually decreasing the depth of the concave portion with respect to the printing direction.

  In a sixth aspect based on the second aspect, the concavo-convex surface is formed such that the holding amount for holding the coating liquid is linearly decreased by linearly decreasing the size of the concave portion with respect to the printing direction. The

  In a seventh aspect based on the second aspect, the concavo-convex surface is formed such that the holding amount for holding the coating liquid gradually decreases by gradually decreasing the size of the concave portion with respect to the printing direction. The

  According to the first invention, by using a printing plate having a concavo-convex surface formed so that the holding amount for holding the coating liquid gradually decreases with respect to the printing direction of the printing plate that sequentially faces the upper surface of the substrate, Since the uniformity of the transfer amount of the coating liquid printed on the substrate is improved, it is possible to form a thin film with high film thickness uniformity. For example, the holding amount of the coating liquid on the upper surface of the convex pattern is increased from the back to the top so as to complement the transfer amount that is reduced by the coating liquid pushed from the top to the back in the printing direction. Since the increase in the holding amount can cancel out the transfer amount that decreases, it is possible to prevent a phenomenon in which the transfer amount of the coating liquid increases toward the back of the printing application.

  According to the second aspect of the invention, when supplying the coating liquid to the printing plate, the coating liquid is mainly held in the concave portion of the concavo-convex surface. Therefore, by gradually reducing the size of the concave portion with respect to the printing direction, The holding amount for holding the coating liquid with respect to the printing direction can be easily gradually reduced.

  According to the third aspect, by gradually increasing the size of the convex portion of the concavo-convex surface with respect to the printing direction, the size of the concave portion with respect to the printing direction can be gradually decreased.

  According to the fourth aspect of the invention, by gradually increasing the arrangement pitch of the convex portions of the concavo-convex surface with respect to the printing direction, the size of the concave portions with respect to the printing direction can be easily reduced.

  According to the fifth aspect of the invention, when supplying the coating liquid to the printing plate, the coating liquid is mainly held in the concave portion of the uneven surface. Therefore, by gradually reducing the depth of the concave portion with respect to the printing direction, The holding amount for holding the coating liquid with respect to the printing direction can be easily gradually reduced.

  According to the sixth aspect of the invention, it is possible to increase the holding amount of the coating liquid so as to supplement the transfer amount that linearly decreases with the coating liquid pushed from the top to the back in the printing direction.

  According to the seventh aspect, it becomes easy to form an uneven surface on the upper surface of the convex pattern of the printing plate.

  Hereinafter, with reference to FIG. 1, the coating device 1 which concerns on one Embodiment of this invention is demonstrated. In order to make the description more specific, the application apparatus 1 is applied to an application apparatus that manufactures an organic EL device that uses an organic EL material, a hole transport material, an electron transport material, and the like as a coating liquid. Will be explained. The coating apparatus 1 forms an organic EL material, a hole transport material, an electron transport material, and the like in a thin film shape of, for example, 150 mm square or 300 mm square on an object to be coated (for example, a glass substrate) placed on a stage. An organic EL device is manufactured by printing and coating. In addition, the coating apparatus 1 uses a plurality of coating liquids such as an organic EL material, a hole transport material, and an electron transport material as described above. An example in which a molecular material (hereinafter referred to as a polymer organic EL material) is used as a coating solution will be described. FIG. 1 is a perspective view illustrating a schematic configuration of a main part of the coating apparatus 1.

  In FIG. 1, the coating apparatus 1 generally includes a plate cylinder 11 around which a printing plate 12 is wound, a coating liquid supply unit 20, a substrate transport mechanism 50, and a lifting mechanism 60. In FIG. 1, as a configuration of the coating liquid supply unit 20, a coating liquid supply roller 21, a slit nozzle 22, a first motor 28, and a second motor 29 are illustrated. The substrate transport mechanism 50 includes a base 51, a pair of transport guide members 52, a transport drive unit 53, and a transport table 54. The elevating mechanism 60 includes an elevating table 61, a pair of elevating guide members 62, an elevating drive unit 63, and a support side plate 64.

  The pair of transport guide members 52 are fixed to the upper surface of the base 51 so as to extend in a horizontal direction perpendicular to the axis of the plate cylinder 11. The transport driving unit 53 is configured by, for example, a linear motor whose driving direction is the extending direction of the pair of transport guide members 52. The transfer table 54 places a substrate P, which is an example of an object to be coated, on the upper surface thereof. The transport table 54 is connected to the pair of transport guide members 52 and the transport drive unit 53, receives the driving force of the transport drive unit 53, and moves the substrate P in the horizontal direction perpendicular to the axis of the plate cylinder 11. Is moved back and forth.

  The support side plates 64 are configured as a pair of left and right with respect to the lifting table 61 and are fixed to the lifting table 61, respectively. On the other hand, on the base 51, a pair of elevating guide members 62 are extended in the vertical direction. The raising / lowering drive part 63 makes the extending direction of the raising / lowering guide member 62 a drive direction, for example, is comprised by the ball screw provided in the said extending direction, and the motor which rotates the said ball screw. A plate cylinder 11 and a coating liquid supply unit 20 are mounted on the lifting table 61. The support side plate 64 fixed to the elevating table 61 is connected to the elevating guide member 62 and the elevating drive unit 63, and can be moved up and down along the elevating guide member 62 by receiving a driving force from the elevating drive unit 63. It becomes. Therefore, the plate cylinder 11 and the coating liquid supply unit 20 can move up and down together with the lifting table 61 by receiving the driving force of the lifting drive unit 63. Moreover, the 1st motor 28 and the 2nd motor 29 raise / lower the slit nozzle 22 according to those drive.

  Next, basic configurations of the plate cylinder 11 and the coating liquid supply unit 20 will be described with reference to FIG. FIG. 2 is a schematic diagram showing the main part of the coating apparatus 1.

  In FIG. 2, a printing plate 12 is wound around and fixed to the outer circumferential surface of the plate cylinder 11, and its axis is arranged in the horizontal direction. On the surface of the printing plate 12, a pattern of a coating liquid to be transferred to the substrate P (for example, a 150 mm square plane) is formed in a convex shape. Specifically, the printing plate 12 has a base portion 121 and a pattern portion 122. The base portion 121 is supported by the plate cylinder 11 in contact with the outer circumferential surface of the plate cylinder 11. The pattern portion 122 is formed in a convex shape corresponding to the pattern shape to be transferred to the substrate P on the outside of the base portion 121 in contact with the plate cylinder 11. Fine irregularities are formed on the upper surface of the pattern portion 122 (that is, the upper surface of the convex pattern). For example, the printing plate 12 is a flexographic plate and is made of a flexible material such as a photosensitive material. The detailed shape of the printing plate 12 will be described later.

  The plate cylinder 11 is provided so as to be rotatable in the direction of the arrow A in the drawing centered on the axis while the printing plate 12 is supported on the outer circumferential surface, and receives a driving force from a rotation driving mechanism (not shown) at a predetermined rotation speed. Rotate. A transport table 54 is disposed in the lower space of the plate cylinder 11. As described above, the substrate P is placed on the upper surface of the transfer table 54 so as to be horizontally movable, and receives the driving force from the transfer drive unit 53 and moves horizontally at a predetermined moving speed. The transport table 54 passes through the lower space of the plate cylinder 11 by horizontally moving in the direction of the arrow B, which is the horizontal direction perpendicular to the axis of the plate cylinder 11. At this time, the elevating table 61 is set so that the gap generated between the substrate P previously placed on the transport table 54 and the printing plate 12 fixed to the plate cylinder 11 or the amount of pressing against the substrate P is within a predetermined range. The position of (see FIG. 1) is adjusted.

  A control unit (not shown) of the coating apparatus 1 controls the transport driving unit 53 to horizontally move the transport table 54 on which the substrate P is placed in the direction of the arrow B in the drawing so as to pass through the lower space of the plate cylinder 11. At this time, the plate cylinder 11 is rotated in the direction of the arrow A in the figure so as not to cause a difference in speed according to the horizontal movement speed of the transport table 54 by controlling the rotation driving mechanism. Thus, the coating liquid (polymer organic EL material) supplied to the printing plate 12 is applied to the substrate P while the substrate P placed on the transport table 54 and the printing plate 12 face each other while maintaining a predetermined gap. It will be transcribed. In the following description, when the polymer organic EL material is printed on the substrate P by rotating the plate cylinder 11 in the direction of the arrow A, the pattern portion 122 of the printing plate 12 and the substrate P first face each other. The part is set as a printing front end position 122 s of the pattern unit 122. Further, a portion where the pattern portion 122 of the printing plate 12 and the substrate P finally face each other is set as a printing rear end position 122 e of the pattern portion 122.

  The coating liquid supply roller 21 is arranged such that its axis is parallel to the axis of the plate cylinder 11. For example, the coating liquid supply roller 21 is configured by a flat roller having a smooth circumferential surface. The coating liquid supply roller 21 rotates in opposite directions (in the direction of the arrow C in the figure) while the circumferential surface thereof is in contact with the printing plate 12 wound around the plate cylinder 11, so that the surface of the printing plate 12. Is supplied with a coating solution (polymer organic EL material).

  The coating liquid supply roller 21 is pivotally supported by a pair of left and right roller support portions. The plate cylinder 11 is also pivotally supported by a pair of left and right plate cylinder supports. The roller support portion is configured to be able to contact and separate from the plate cylinder support portion.

  The coating liquid supply unit 20 includes a cleaning mechanism 23 and a supply source 24 in addition to the configuration shown in FIG. The supply source 24 stores a polymer organic EL material to be printed and applied to the substrate P, and supplies a predetermined amount of the polymer organic EL material to the slit nozzle 22. The slit nozzle 22 has a slit whose longitudinal direction is the axial direction of the coating liquid supply roller 21. The slit nozzle 22 ejects the polymer organic EL material supplied from the supply source 24 from the slit onto the circumferential surface of the coating liquid supply roller 21 at a predetermined flow rate, and the polymer on the circumferential surface. A thin film of organic EL material is formed. The slit of the slit nozzle 22 is spaced from the circumferential surface of the coating liquid supply roller 21 by a predetermined distance, and the distance drives the first motor 28 and the second motor 29 (see FIG. 1), respectively. Adjusted by. Then, the circumferential surface of the coating liquid supply roller 21 after the polymer organic EL material is supplied to the surface of the printing plate 12 is cleaned by the cleaning mechanism 23. A structural example of the cleaning mechanism 23 will be described later. In addition, the surface of the printing plate 12 after the polymer organic EL material is transferred to the substrate P may be cleaned by a cleaning mechanism (not shown).

  Thus, in the coating apparatus 1, the polymer organic EL material is supplied from the slit nozzle 22 to the surface of the coating liquid supply roller 21, and a thin film of the polymer organic EL material is formed on the surface of the coating liquid supply roller 21. . The polymer organic EL material is transferred to a convex pattern formed on the printing plate 12, and a thin film pattern of the polymer organic EL material is formed on the printing plate 12. A thin film pattern of the polymer organic EL material formed on the printing plate 12 is printed on the substrate P. For example, by forming a convex planar pattern as the pattern portion 122 of the printing plate 12, the polymer organic EL material can be printed and applied on the substrate P in a thin film state corresponding to the planar pattern.

  Next, a configuration example of the cleaning mechanism 23 will be described with reference to FIG. FIG. 3 is a schematic diagram illustrating an example of the cleaning mechanism 23.

  In FIG. 3, when the polymer organic EL material remains on the surface of the coating liquid supply roller 21, the polymer organic EL material is further supplied from the slit nozzle 22 from above. In this case, the film thickness of the polymer organic EL material on the surface of the coating liquid supply roller 21 increases and becomes non-uniform. As a result, the polymer organic EL material having poor uniformity is printed and applied to the substrate P. In order to prevent such unevenness of the polymer organic EL material, the surface of the coating liquid supply roller 21 after the polymer organic EL material is supplied to the surface of the printing plate 12 is cleaned by the cleaning mechanism 23. The cleaning mechanism 23 includes a cleaning liquid container 231, a first blade 232, a second blade 233, and a recovery conduit 234.

  The first blade 232 scrapes off the main polymer organic EL material remaining on the surface of the coating liquid supply roller 21 after supplying the polymer organic EL material to the surface of the printing plate 12. The recovery conduit 234 recovers the polymer organic EL material scraped off by the first blade 232. Before the polymer organic EL material is scraped off by the first blade 232, a rinse liquid (for example, polymer organic EL) is applied to the surface of the coating liquid supply roller 21 after the polymer organic EL material is supplied to the surface of the printing plate 12. The solvent for the EL material may be supplied. In this case, the first blade 232 scrapes off the main polymer organic EL material remaining on the surface of the coating liquid supply roller 21 together with the rinse liquid, and the recovery pipe 234 is scraped off by the first blade 232. The polymer organic EL material and the rinse liquid are collected. By supplying the rinsing liquid in this way, the remaining polymer organic EL material can be prevented from solidifying.

  The cleaning liquid container 231 is a container whose upper surface is opened, and stores the cleaning liquid C (for example, a solvent of the polymer organic EL material) therein. The cleaning liquid container 231 removes a part (specifically, the lowermost surface) of the surface of the coating liquid supply roller 21 after the main polymer organic EL material is scraped off by the first blade 232. Immerse in C. Then, the second blade 233 scrapes off the cleaning liquid C remaining on the surface of the coating liquid supply roller 21 after being immersed in the cleaning liquid C.

  Next, the shape of the printing plate 12 will be described with reference to FIGS. FIG. 4 is a side view showing an example of the shape of the printing plate 12 developed in a planar shape. FIG. 5 is a top view showing an example of the shape of the printing plate 12 developed in a planar shape. FIG. 6 is a plan view showing an example of a halftone dot pattern M formed on the surface of the pattern portion 122. FIG. 7 is a cross-sectional view of the halftone dot pattern M when the cross-section AA of FIG. 6 is viewed from the B direction. FIG. 8 is a cross-sectional view of the halftone dot pattern M when the cross-section CC of FIG. 6 is viewed from the D direction. FIG. 9 is a diagram illustrating an example of changing the specifications of the halftone dot pattern M by changing the halftone dot diameter Dm from the printing leading edge position 122s to the printing trailing edge position 122e.

  4 and 5, the printing plate 12 has a base portion 121 and a pattern portion 122. In FIGS. 4 and 5, the printing leading edge position 122s of the pattern portion 122 is arranged on the left side, and the printing trailing edge position 122e is arranged on the right side. Therefore, when the printing plate 12 is wound around the plate cylinder 11, the printing plate 12 faces the substrate P in order from the left side to the right side of the upper surface of the pattern portion 122 shown in FIGS. 4 and 5 (printing direction in the drawing). The base portion 121 is supported by the plate cylinder 11 with its lower surface abutting on the outer circumferential surface of the plate cylinder 11. Further, the pattern part 122 is formed in a convex shape with respect to the upper surface of the base part 121 in a shape corresponding to the pattern shape to be transferred to the substrate P. A halftone dot pattern M having a fine concavo-convex shape is formed on the entire upper surface of the pattern portion 122 (that is, the surface facing the substrate P). Note that the base portion 121 and the pattern portion 122 may be formed by being integrally formed, or may be formed by bonding to each other using adhesion or mechanical bonding.

  5 and 6, the halftone dot pattern M has fine convex dots (hereinafter referred to as halftone dots) formed in a lattice pattern at predetermined intervals. In other words, the upper surface of the pattern portion 122 is not a smooth surface but has fine irregularities formed by a pattern of convex halftone dots. For example, the halftone dot pattern M is finely processed on the upper surface of the pattern portion 122 by exposing the photosensitive material according to the halftone dot pattern.

  As shown in FIGS. 7 and 8, the convex halftone dot has a circular plane having a diameter Dm (hereinafter referred to as a halftone dot diameter Dm) formed at the topmost part Mt. The halftone dots are formed in a shape (conical shape in which a flat portion is formed at the tip) that gradually spreads toward the deepest portion of the concave portion R while gradually spreading from the circular plane as the top. That is, the concave portion R is formed around the halftone dot. In the following description, the interval between adjacent halftone dots is defined as a halftone dot pitch Pm. Specifically, as shown in FIG. 6 and FIG. 7, in the halftone dots arranged in a grid, the halftone dots adjacent in the vertical or horizontal direction are closest to the grid, and A center-to-center pitch between adjacent topmost parts Mt is defined as a halftone dot pitch Pm. In the following description, the deepest depth of the recess R is defined as the deepest relief depth Rd. Specifically, as shown in FIGS. 6 and 8, in the halftone dots arranged in a lattice pattern, the deepest concave portion R is the intermediate position between the halftone dots that are obliquely adjacent to the lattice. Therefore, the depth of the concave portion R at the intermediate position is the deepest relief depth Rd.

  In the present embodiment, the halftone dot diameter M of the halftone dot pattern M on the upper surface of the pattern portion 122 gradually changes between the printing leading edge position 122s and the printing trailing edge position 122e. For example, as shown in FIGS. 5 and 9, the halftone dot pattern M on the upper surface of the pattern portion 122 has a halftone dot diameter Dm from the minimum halftone dot diameter Dms to the maximum between the printing leading edge position 122s and the printing trailing edge position 122e. The dot pitch Pm is made constant so as to change linearly up to the dot diameter Dml.

  In this way, when the halftone dot pitch Pm is kept constant and the halftone dot diameter Dm is changed, the width of the concave portion R also changes in accordance with the change, so the depth of the deepest relief depth Rd also changes. Specifically, as shown in FIG. 9, as the halftone dot diameter Dm gradually increases from the minimum halftone dot diameter Dms to the maximum halftone dot diameter Dml, the deepest relief depth Rd is a relatively deep relief depth. It gradually decreases from Rdd to a relatively shallow relief depth Rds. Accordingly, in the halftone dot pattern M on the upper surface of the pattern portion 122, the deepest relief depth Rd linearly changes from the relief depth Rdd to the relief depth Rds (Rdd> Rds) between the printing leading edge position 122s and the printing trailing edge position 122e. .

  In this way, the specification of the halftone dot pattern M formed on the upper surface of the pattern portion 122 is changed from the print leading edge position 122s to the printing rear edge position 122e, thereby holding the polymer organic EL material held on the upper surface of the pattern portion 122. The amount can be varied. Specifically, when the coating liquid supply roller 21 supplies the polymer organic EL material to the surface of the printing plate 12, the polymer organic EL material is held by the concave portion R or the topmost portion Mt of the halftone dot pattern M. Typically, the polymer organic EL material is held at least by the recesses R of the halftone dot pattern M. Therefore, if the volume of the recesses R formed around the halftone dots is large, the height held by the recesses R is high. The amount of molecular organic EL material held increases. The deepest relief depth Rd gradually decreases from the printing leading end position 122s on the upper surface of the pattern portion 122 toward the printing trailing end position 122e. Therefore, the holding amount of the polymer organic EL material gradually decreases from the printing leading edge position 122s on the upper surface of the pattern portion 122 toward the printing trailing edge position 122e.

  On the other hand, when the coating apparatus 1 contacts and transfers the polymer organic EL material, a phenomenon occurs in which the polymer organic EL material is pushed backward. As an example, in the coating apparatus 1, at the stage of transferring the polymer organic EL material from the coating liquid supply roller 21 to the printing plate 12, the back of the printing plate 12 (that is, the printing rear end position 122 e side on the upper surface of the pattern unit 122) There is a tendency that the holding amount of the polymer organic EL material is increased. As another example, in the coating apparatus 1, at the stage of transferring the polymer organic EL material from the printing plate 12 to the substrate P, the rear side of the substrate P to be printed and coated (that is, the printing rear end position 122e side on the upper surface of the pattern portion 122). There is a tendency that the transfer amount of the polymer organic EL material increases.

  However, such a tendency can be offset by changing the specification of the halftone dot pattern M formed on the upper surface of the pattern portion 122 from the printing leading edge position 122s to the printing trailing edge position 122e. For example, holding the polymer organic EL material on the upper surface of the pattern portion 122 from the back to the top so as to complement the transfer amount reduced by the polymer organic EL material pushed back from the top of printing due to the phenomenon described above. Increase the amount. That is, the amount of the polymer organic EL material is gradually decreased from the printing leading end position 122s on the upper surface of the pattern portion 122 toward the printing trailing end position 122e, thereby transferring the polymer organic EL material toward the rear side where printing is applied. It becomes possible to prevent the phenomenon that the amount increases. Therefore, since the uniformity of the transfer amount of the polymer organic EL material printed and applied to the substrate P is improved, it is possible to form a thin film with high film thickness uniformity. In addition, about the edge part of the pattern part 122 upper surface, you may form a halftone dot with the halftone dot diameter Dm relatively larger than the halftone dot diameter Dm currently formed in the inner upper surface.

  Here, consider a case where a polymer organic EL material is printed and coated on the substrate P in a thin film shape of 150 mm square by the coating apparatus 1. Then, on the upper surface of the pattern portion 122, a halftone dot pattern P is constant at a halftone dot pitch Pm = 85 μm (micrometer) (screen line number 300 lpi), a constant halftone dot diameter Dm = 66 μm, and a maximum relief depth Rd = 20 μm. Form. When the polymer organic EL material is printed and applied to the substrate P using the printing plate 12 created under these conditions, the average film thickness at the top part of the print application is about 60 nm (nanometer), and the average film thickness at the central part of the print application Was about 80 nm, and the average film thickness at the end portion after printing was about 100 nm. That is, the film thickness of the polymer organic EL material tends to be thicker toward the back of the substrate P to be printed (that is, the print rear end position 122e side of the upper surface of the pattern portion 122).

  On the other hand, on the upper surface of the pattern portion 122, the halftone dot pitch Pm = 85 μm is constant (screen line number 300 lpi), and the halftone dot diameter Dm is linearly changed from 66 μm to 80 μm from the printing leading edge position 122s to the printing trailing edge position 122e. A dot pattern M is formed by linearly changing from a printing leading edge position 122s to a printing trailing edge position 122e from 20 μm to 12 μm. When the polymer organic EL material is printed and applied to the substrate P using the printing plate 12 created under these conditions, the average film thickness of the print application head part is about 60 nm, the average film thickness of the print application center part is about 60 nm, The average film thickness at the end portion after printing was about 60 nm. That is, by changing the specification of the halftone dot pattern M formed on the upper surface of the pattern portion 122 from the printing leading edge position 122s to the printing trailing edge position 122e, the film thickness is uniform over the entire surface of the substrate P to be printed. A polymer organic EL material can be printed and applied.

  In the above description, the holding amount of the polymer organic EL material on the upper surface of the pattern portion 122 is changed by changing the dot diameter Dm while keeping the dot pitch Pm constant, but other dot specifications are used. It may be changed to change the holding amount. For example, the holding amount of the polymer organic EL material on the upper surface of the pattern portion 122 may be changed by changing the dot pitch Pm while keeping the dot diameter Dm constant.

  FIG. 10 is a diagram showing an example of changing the specifications of the halftone dot pattern M by changing the halftone dot pitch Pm from the printing leading edge position 122s to the printing trailing edge position 122e. In FIG. 10, in the halftone dot pattern M on the upper surface of the pattern portion 122, the halftone dot pitch Pm gradually decreases between the printing leading edge position 122s and the printing trailing edge position 122e. For example, as shown in FIG. 10, the halftone dot pattern M on the upper surface of the pattern portion 122 has a halftone dot pitch Pm from the maximum halftone dot pitch Pml to the minimum halftone dot pitch between the printing leading edge position 122s and the printing trailing edge position 122e. The dot diameter Dm is constant so as to change linearly up to Pms.

  As described above, when the halftone dot diameter Dm is kept constant and the halftone dot pitch Pm is changed, the width of the concave portion R also changes in accordance with the change, so that the depth of the deepest relief depth Rd also changes. Specifically, as shown in FIG. 10, the deepest relief depth Rd is a relatively deep relief depth in response to the halftone dot pitch Pm gradually decreasing from the maximum halftone dot pitch Pml to the minimum halftone dot pitch Pms. It gradually decreases from Rdd to a relatively shallow relief depth Rds. Therefore, the halftone dot pattern M on the upper surface of the pattern portion 122 has the deepest relief depth Rd from the relief depth Rdd to the relief depth Rds (Rdd> Rds) between the printing leading edge position 122s and the printing trailing edge position 122e, as in FIG. ) Linearly. Thus, even if the dot pattern P is changed by changing the dot pitch Pm, the polymer organic EL material gradually decreases from the print leading edge position 122s on the upper surface of the pattern portion 122 toward the printing trailing edge position 122e. The holding amount of can be reduced. As for the end portion of the upper surface of the pattern portion 122, halftone dots may be formed with a halftone dot pitch Pm relatively shorter than the halftone dot pitch Pm formed on the inner upper surface thereof.

  Further, the specification of the halftone dot pattern M may be changed by adding the change of the halftone dot pitch Pm to the change of the halftone dot diameter Dm. Specifically, the halftone dot pitch Pm is gradually changed while the halftone dot diameter Dm is gradually changed from the printing leading edge position 122s to the printing trailing edge position 122e. Thus, even when both the halftone dot diameter Dm and the halftone dot pitch Pm are changed from the printing leading edge position 122s to the printing trailing edge position 122e, the deepest relief depth Rd can be gradually changed. The holding amount of the polymer organic EL material can be gradually reduced from the printing leading end position 122s on the upper surface of the pattern portion 122 toward the printing trailing end position 122e.

  In the above description, the halftone dot pattern M on the upper surface of the pattern portion 122 linearly changes the halftone dot diameter Dm and / or the halftone dot pitch Pm between the printing leading edge position 122s and the printing trailing edge position 122e. However, the halftone dot pattern M may be formed by other changes.

  As a first example, the halftone dot pattern M is formed by gradually changing the halftone dot diameter Dm and / or the halftone dot pitch Pm from the printing leading edge position 122s to the printing trailing edge position 122e. For example, as shown in FIG. 11, the halftone dot diameter Dm is gradually changed from the minimum halftone dot diameter Dms to the maximum halftone dot diameter Dml between the printing leading end position 122s and the printing trailing end position 122e. Thus, a halftone dot pattern M is formed. As a result, the deepest relief depth Rd changes stepwise (five steps) from a relatively deep relief depth Rdd to a relatively shallow relief depth Rds. That is, when the specification of the halftone dot pattern M formed on the upper surface of the pattern portion 122 is changed stepwise, the polymer organic EL material is moved from the print leading end position 122s on the upper surface of the pattern portion 122 toward the printing rear end position 122e. The holding amount decreases step by step. As described above, even if the amount of the polymer organic EL material retained is changed stepwise, it is possible to prevent a phenomenon in which the amount of the polymer organic EL material transferred increases toward the back of the printing application.

  As a second example, the halftone dot pattern M is formed by changing the halftone dot diameter Dm and / or the halftone dot pitch Pm nonlinearly between the printing leading edge position 122s and the printing trailing edge position 122e. For example, by changing the halftone dot diameter Dm from the minimum halftone dot diameter Dms to the maximum halftone dot diameter Dml between the printing leading end position 122s and the printing trailing end position 122e, A pattern M is formed.

  Further, each setting value and relational expression described above are merely examples, and it goes without saying that the present invention can be realized even with other setting values and relational expressions. For example, the relational expression for changing the dot diameter Dm and / or the dot pitch Pm and the setting of the minimum value / maximum value are the properties of the coating liquid (material, solvent, viscosity, etc.), printing coating amount (coating flow rate, target film). Thickness, printing application area, etc.), printing application speed, transfer conditions (transfer interval, pressing force, each material, shape, etc. of application liquid supply roller 21, printing plate 12, and substrate P), application environment (temperature, humidity, etc.) ), Etc., may be set as appropriate.

  In the above description, the halftone dot pattern M is formed by arranging the halftone dots in a square lattice pattern, but the halftone dots may be arranged in other arrangement patterns. For example, a halftone dot pattern M may be formed by arranging halftone dots in a so-called honeycomb arrangement in which the halftone dot arrangement position is shifted in the arrangement direction by 1/2 of the halftone dot pitch Pm for each arrangement line. Absent.

  In the above description, the halftone dot pattern M is formed using a halftone dot having a circular plane formed at the topmost part Mt, but a halftone dot having another shape may be used. For example, the halftone dot pattern M may be formed using a halftone dot in which an ellipse or a polygonal plane is formed at the topmost part Mt. Further, the halftone dot pattern M may be formed using a halftone dot in which a flat surface is not formed on the topmost part Mt, such as a dome shape or a conical shape.

  In the above-described embodiment, the example in which the coating apparatus 1 prints and applies the polymer organic EL material forming the light emitting layer onto the substrate P as the coating liquid is used. It goes without saying that the polymer organic EL material, the blue light emitting polymer organic EL material, and the white light emitting polymer organic EL material can be printed and applied as coating solutions, respectively. The coating apparatus of the present invention can also be used when other coating liquids such as a hole transport material and an electron transport material are printed and applied. In the coating apparatus of the present invention, a low molecular material may be used as the coating liquid as the organic EL material for forming the light emitting layer.

  Specifically, when the coating apparatus 1 in the embodiment described above prints and applies a hole transport material, this coating process is an intermediate process for manufacturing an organic EL device. When manufacturing organic EL devices, hole transport material (eg, PEDOT) printing coating, red light emitting polymer organic EL material printing coating, green light emitting polymer organic EL material printing coating, blue light emitting polymer organic EL There are coating processes such as material printing and coating, white light emitting polymer organic EL material printing and electron transport material printing, and the coating apparatus of the present invention can be used in any printing coating process.

  Examples of the red, green, blue, and white light emitting organic light emitting materials used by the coating apparatus 1 in the embodiment described above include, for example, quinolinol metal complexes, benzoquinolinol metal complexes, benzoxazole metal complexes, phthalocyanines, and polyferrins. , Azomethine-based metal complexes, phenanthroline europium complexes, styryl and distyryl compounds, condensed aromatic compounds such as pyrene, rubrene, coronene, chrysene, diphenylanthracene, heteroaromatic compounds such as oxadiazoles, thiadiazoles, triazoles, quinacridone And π-conjugated compounds such as polyphenylene, polypyridine, polythiophene, polyfluorene, polyphenylene vinylene, and the like can be used. However, the organic light emitting material used in the coating apparatus 1 is not limited to these exemplified materials, and other materials may be used.

  Examples of the hole transport material used by the coating apparatus 1 in the above-described embodiment include, for example, polyvinyl carbazole and derivatives thereof, polythiophene and derivatives thereof, polyphenylene and derivatives thereof, polyphenylene vinylene and derivatives thereof, and polyolefin having a triarylamine skeleton. Polyacrylic, polyarylate, polycarbonate, polyester, polyamide, polyurethane, polyimide and the like can be used. However, the hole transport material used in the coating apparatus 1 is not limited to these exemplified materials, and other materials may be used.

  Moreover, in embodiment mentioned above, although the glass substrate was used as an example of a to-be-coated body, another member can also be used as a to-be-coated body. For example, a flexible substrate made of polyethylene terephthalate (PET), polycarbonate (PC), or the like may be used as the coating object of the coating apparatus 1.

  In the above description, the printing cylinder 11 is rotated while horizontally moving the conveyance table 54 on which the substrate P is placed, and printing is applied. However, the conveyance table 54 is fixed and the plate cylinder 11 itself is placed in the horizontal direction. It may be rotated while moving in the horizontal direction opposite to the moving direction. Needless to say, if at least one of the plate cylinder 11 and the transport table 54 moves relatively in the horizontal direction, the same printing application is possible.

  In the embodiment described above, the slit nozzle 22 having a slit whose longitudinal direction is the axial direction of the coating liquid supply roller 21 is used as a nozzle for supplying the coating liquid to the surface of the coating liquid supply roller 21. However, other nozzles may be used. A nozzle having a plurality of discharge ports may be used as long as the polymer organic EL material at a predetermined flow rate can be supplied to the surface of the coating liquid supply roller 21 along the axial direction of the coating liquid supply roller 21. . For example, a nozzle in which a large number of discharge ports are arranged in the axial direction of the coating liquid supply roller 21 may be used.

  The coating apparatus and the coating method according to the present invention can improve the film thickness uniformity when printing and coating a coating liquid containing an organic EL material, and manufactures an organic EL device used for illumination, a display, or the like. It is useful as a method and the like.

The perspective view which shows the principal part schematic structure of the coating device 1 which concerns on one Embodiment of this invention. Schematic diagram showing the main part of the coating apparatus 1 of the coating apparatus 1 of FIG. Schematic diagram showing an example of the cleaning mechanism 23 of FIG. The side view which shows an example of the shape which expand | deployed the printing plate 12 of FIG. 1 planarly 1 is a top view showing an example of a shape in which the printing plate 12 of FIG. The top view which shows an example of the halftone dot pattern M formed in the surface of the pattern part 122 of FIG. Sectional view of the halftone dot pattern M when the section AA of FIG. Sectional drawing of the halftone dot pattern M which looked at the cross section CC of FIG. 6 from D direction The figure which shows an example which changes the specification of the halftone dot pattern M by changing the halftone dot diameter Dm from the printing leading end position 122s to the printing rear end position 122e. The figure which shows an example which changes the specification of the halftone dot pattern M by changing the halftone dot pitch Pm from the printing leading end position 122s to the printing rear end position 122e. The figure which shows an example which changes the specification of the halftone dot pattern M by changing the halftone dot diameter Dm from the printing leading end position 122s to the printing rear end position 122e stepwise.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Coating apparatus 11 ... Plate cylinder 12 ... Printing plate 121 ... Base part 122 ... Pattern part 20 ... Coating liquid supply part 21 ... Coating liquid supply roller 22 ... Slit nozzle 23 ... Cleaning mechanism 231 ... Cleaning liquid container 232 ... 1st blade 233 ... second blade 234 ... recovery pipeline 24 ... supply source 28 ... first motor 29 ... second motor 50 ... substrate transport mechanism 51 ... base 52 ... transport guide member 53 ... transport drive unit 54 ... transport table 60 ... lifting mechanism 61 ... Lifting table 62 ... Lifting guide member 63 ... Lifting drive unit 64 ... Support side plate

Claims (7)

A coating apparatus that prints and applies a coating liquid containing an organic EL material on a substrate,
A mounting table on which the substrate is mounted;
Plate cylinder,
Printing in which a convex pattern corresponding to a pattern to be printed and applied on the surface of the plate cylinder is formed on the outer peripheral surface of the plate cylinder, and a dot-shaped uneven surface for holding the coating liquid is formed on the upper surface of the convex pattern Edition,
A coating solution supply section for supplying the coating solution to the surface of the printing plate;
Relative moving means for relatively moving the mounting table and the plate cylinder while rotating the plate cylinder around an axis center in a state where the upper surface of the substrate and the printing plate are brought close to or in contact with each other. Prepared,
The concavo-convex surface is formed by a coating apparatus such that a holding amount for holding the coating liquid gradually decreases with respect to a printing direction of the printing plate that the relative moving unit sequentially faces the upper surface of the substrate. The uneven surface has a plurality of convex portions arranged in a dot pattern and concave portions formed around the convex portions,
2. The coating apparatus according to claim 1, wherein the uneven surface is formed such that a holding amount for holding the coating liquid is gradually decreased by gradually decreasing a size of the recess with respect to the printing direction.   The coating apparatus according to claim 2, wherein the uneven surface gradually decreases the size of the concave portion with respect to the printing direction by gradually increasing the size of the convex portion with respect to the printing direction.   The said uneven | corrugated surface is a coating device of Claim 2 which reduces the magnitude | size of the said recessed part with respect to the said printing direction by shortening the arrangement space | interval of the said convex part with respect to the said printing direction gradually. The uneven surface has a plurality of convex portions arranged in a dot pattern and concave portions formed around the convex portions,
The coating apparatus according to claim 1, wherein the uneven surface is formed such that a holding amount for holding the coating liquid is gradually decreased by gradually decreasing a depth of the recess with respect to the printing direction.   3. The coating according to claim 2, wherein the uneven surface is formed such that a holding amount for holding the coating liquid is linearly decreased by linearly decreasing a size of the concave portion with respect to the printing direction. apparatus.   The coating according to claim 2, wherein the uneven surface is formed such that a holding amount for holding the coating liquid gradually decreases by gradually decreasing the size of the recess with respect to the printing direction. apparatus.

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