JP2013202507A - Stripe coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stripe coating method for reducing a coating width of pixels formed between banks to be 100 μm or less, in the stripe coating method by a bead method using a nozzle having a discharge port distal end part for which the periphery of a plurality of discharge ports provided in a nozzle longitudinal direction is projected in a coating liquid discharge direction.SOLUTION: In a stripe coating method, when a fixed coating speed of performing relative movement and coating is in a suitable range of 2.8 Pa or more and 35.0 Pa or less in terms of shearing force in a relative movement direction generated within a bead, by fixing a space amount of a gap without correcting or adjusting it for stable maintenance of the bead 52 and continuing coating at the fixed coating speed, the formation of the bead 52 is maintained, and the stripe of a coating film of a fixed width can be coated. Also, when the fixed coating speed is accelerated within the suitable range, the coating width can be reduced.

Description

  The present invention is an invention in the field of manufacturing a display member, and more particularly, relates to a coating method in which a large number of parallel coating films having a predetermined pitch are formed on a surface of a member to be coated such as a glass substrate.

  As conventionally known, for example, in the manufacturing process of a display panel using a material called an organic EL (Electro Luminescence) material, partitions (hereinafter referred to as banks) arranged in parallel at a predetermined pitch are used. The pixels formed in between are filled with a common layer such as R (red), G (green), and B (blue) coating liquids, HIL (Hole Injection Layers), HTL (Hole Transfer Layers), etc., and dried. There is a step of forming a coating film.

  As a general means for forming such a pixel coating film by filling a groove between parallel banks arranged at a predetermined pitch on a glass substrate, for example, a whole surface coating method such as a slit coating method. And pixel coating methods such as screen printing are known.

  In the entire surface coating method such as the slit coating method, an unnecessary portion is removed after applying a coating solution of a certain color to the entire surface of the substrate, and then, similarly, the entire surface coating of the next color and the removal of the unnecessary portion are repeated twice. I need it. However, since the organic EL material is a self-luminous material, there is a problem that an exposure technique cannot be used in the process of removing the unnecessary portion.

  In the screen printing method, pixels can be applied separately, but a material such as a screen is required separately, and it is necessary to replace the material whenever the material deteriorates.

  For this reason, a pixel coating method that can form a coating film with only a necessary amount of an expensive coating liquid, particularly an inkjet method and a continuous discharge nozzle method that do not require materials are drawing attention.

  The ink jet method is a method of filling a pixel formed between banks with a coating solution, and is divided into a method of driving a piezo and a method of intermittently ejecting the coating solution from a nozzle by applying heat.

  In the inkjet method, since the ejection of the coating liquid can be controlled for each of a large number of ejection ports provided in the nozzle, the selection of the ejection ports to be ejected, the number of ejection times, the amount of the coating liquid, and the like can be set according to the pixel width shape and the coating film thickness. Although there are advantages that can be set according to the thickness, it is difficult to eject from all the nozzles with a uniform discharge amount, and there are problems in the stability of discharge and the uniformity of the thickness of the coating film.

  In addition, it is necessary to adjust the viscosity of the coating liquid that can be sprayed from the discharge port of the nozzle, and there is a limitation on the applicable coating liquid.

  On the other hand, in the continuous discharge nozzle method, since the coating liquid is continuously discharged from a large number of discharge ports provided in the longitudinal direction of the nozzle, the member to be coated is relatively moved in a direction perpendicular to the longitudinal direction of the nozzle. Thus, the coating liquid can be applied simultaneously to the pixels formed between the banks. Since the ejection stability and the uniformity of the coating film thickness are superior to those of the ink jet method, they are widely used (for example, Patent Document 1).

  For example, as shown in Patent Document 2, in manufacturing a back plate of a plasma display panel, it is used in a step of applying a phosphor paste to a groove between predetermined banks.

  According to Patent Document 2, generally, the viscosity of the phosphor paste used for manufacturing the back plate of the plasma display panel is 10 Pa · s or less, and the shape of the bank provided on the member to be coated is about 20 in width. ˜120 μm and height 50 to 250 μm.

  Furthermore, also in the continuous discharge nozzle method, the amount of clearance between the nozzle discharge port and the member to be coated (hereinafter referred to as a gap) is relatively large so that the coating liquid flows from the nozzle discharge port. A columnar flow method (e.g., Patent Document 3) in which the coated member is moved relative to a direction perpendicular to the longitudinal direction of the nozzle while discharging a columnar flow (for example, Patent Document 3), and the gap gap A relatively small amount is formed to form a bead as a liquid pool between the nozzle outlet and the coated member, and the coated member is relatively moved in a direction perpendicular to the longitudinal direction of the nozzle while forming the bead. There is a bead method in which a coating film is applied by applying the coating method.

  The bead method has a feature that the range of the viscosity of the coating liquid and the coating film thickness that can be applied is wider than that of the columnar flow method, and is easy to use.

  In Patent Document 4, when the bead method is applied, the bead formed between the discharge port of the nozzle and the member to be coated spreads in the longitudinal direction of the nozzle (direction perpendicular to the coating direction) due to the capillary phenomenon of the coating liquid. On the other hand, a nozzle outlet suitable for stripe coating in which a peripheral portion of the nozzle outlet is discharged to form a coating film is disclosed.

  The nozzle suitable for the stripe coating of Patent Document 4 has a plurality of discharge ports, and further has a discharge port front end portion in which the periphery of each discharge port protrudes in the coating liquid discharge direction. Is applied close to the member to be coated, the presence of the tip of the discharge port prevents the bead from widening due to the capillary action of the coating liquid, and the bead having a constant width formed in the gap stabilizes the coating liquid in a stripe shape. It can be applied to the color pixel portion between the black matrixes of the color filter.

  In Patent Document 5, in order to make the application width of the pixels formed between the banks 100 μm or less, the shape of the discharge port of the nozzle disclosed in Patent Document 4, more specifically, the periphery of the discharge port of the nozzle is defined. The shape of the discharge port formed to protrude in the coating liquid discharge direction is improved, and a pair of opposed planes for guiding the coating liquid discharged from the protruding portion in the coating liquid discharge direction is provided. A technique related to the shape of the discharge port of a nozzle formed so as to be parallel to a direction substantially orthogonal to the nozzle longitudinal direction is disclosed.

  However, precise processing of the discharge port of the nozzle with a stripe coating width of 100 μm or less is difficult due to processing limitations, and when the shape of the discharge port becomes complicated, it becomes difficult to form and maintain beads at the start of coating.

JP 2007-313417 A JP 2010-29836 A Japanese Patent No. 3808728 JP 2007-187948 A JP 2011-183291 A

  Even if the bead method is applied and a nozzle suitable for stripe coating disclosed in Patent Document 4 is used, it is difficult to reduce the coating width formed between the banks to 100 μm or less.

  The first problem is that when the coating liquid is stably applied to the surface of the member to be coated by the bead having a certain width formed in the gap, the width of the formed bead at the front end of the discharge port is longer than the width in the nozzle direction. Since a large coating width on the surface of the coated member is a stable condition of the bead, in order to reduce the coating width to 100 μm or less, a large number of nozzles are formed by projecting the periphery of the nozzle outlet in the coating liquid discharge direction. The need arises for precision processing to make the width in the longitudinal direction of the nozzle at the front end of the discharge port smaller than the coating width of 100 μm or less.

  However, it is difficult to precisely process a large number of the ejected discharge tip portions in the longitudinal direction of the nozzle smaller than the coating width of 100 μm or less because it approaches the accuracy limit of manufacturing processing.

  On the other hand, as shown in Patent Document 4, when the bead is formed and applied, when the application width formed between the banks is smaller than the width in the nozzle longitudinal direction at the tip of the nozzle outlet, Since it is determined that the formation of the bead is unstable, the coating width formed between the banks is the same or slightly larger than the width in the longitudinal direction of the tip of the nozzle outlet by reducing the gap clearance. It is said that it is preferable to return to a large state so that a stable bead is formed.

  For this reason, if the bead formation becomes unstable, it becomes necessary to correct the gap gap to a smaller value and restore the bead formation to a stable state. However, the coating width formed between the banks becomes 100 μm or less. Since the gap clearance is originally set to be smaller than 100 μm, the tip of the discharge port is not attached to the member to be coated or the above-mentioned attachment due to the deflection or thickness unevenness of the member to be coated, unnecessary deposits, etc. Since there is an increased risk of collision with the kimono, there is a problem that the gap amount of the gap cannot be reduced and adjusted.

  In other words, the first problem is that when the coating width formed between the banks is reduced to 100 μm or less, the width in the longitudinal direction of the nozzle discharge port tip is obtained from the viewpoint of stable bead formation of the coating liquid. Although it is necessary to process the coating width smaller than the coating width, there is a problem that there is a limit to accurately processing the width in the longitudinal direction of the discharge port tip of the nozzle to 100 μm or less due to processing accuracy limitations.

  The second problem is that when the coating width formed between the banks is reduced to 100 μm or less, the gap amount is originally set to be small, so that the deflection or thickness unevenness of the member to be coated is unnecessary. Due to the risk of the tip of the discharge port colliding with the coated member or unnecessary deposits due to the kimono, etc., the gap clearance cannot be corrected and adjusted smaller in order to maintain stable bead formation of the coating liquid. It is a problem.

  In response to these problems, the present invention applies the bead method and uses the nozzle shape having the discharge port front end portion disclosed in Patent Document 4 to make the gap clearance constant without correction adjustment. Thus, the present invention provides a coating method capable of stably forming a coating width having a width equivalent to the width in the longitudinal direction of the tip of the discharge port of the nozzle while maintaining the bead formation of the coating liquid at a constant coating speed.

  In view of the above-mentioned problem that arises from the application width formed between the banks of 100 μm or less, the inventors pay attention to the application speed at which application is performed by relatively moving the nozzle and the member to be applied, A coating test was conducted on the effect of the coating speed on maintaining stable bead formation of the coating solution.

  From the results of various coating tests, if the coating speed is within a suitable range, the gap gap amount is kept constant without correction adjustment, and by continuing the coating at a constant coating speed, the bead formation is maintained, and the discharge port It has been found that a coating film having a width equal to the width in the nozzle longitudinal direction of the tip can be stably formed.

  In addition, when the constant application speed applied by relatively moving is increased, the application width can be reduced to a width equal to the width in the nozzle longitudinal direction of the nozzle outlet, and further, the application speed is increased. After that, the coating film having a width equal to or less than the width in the nozzle longitudinal direction at the tip of the discharge port tends to be dotted, and it has been found that there is an upper limit coating speed at which beads can be stably formed.

  The present invention has been made based on such knowledge. In the invention according to claim 1, the nozzle has a plurality of discharge ports in the longitudinal direction, and the periphery of each of the discharge ports from the nozzle in the coating liquid discharge direction. A plurality of discharge port tip portions formed so as to protrude; the discharge port tip portions are opposed to and close to the surface of the application member in the coating liquid discharge direction; and a gap between the discharge port tip portion and the application member A stripe coating method in which a coating liquid bead is formed and then the nozzle and the member to be coated are moved relative to each other in a direction perpendicular to the longitudinal direction of the nozzle. And a constant coating speed for coating by moving relative to each other with a shearing force in the relative movement direction generated in the bead applied at 2.8 Pa or more and 35.0 Pa or less. Stra It is a flop application method.

  Further, the invention according to claim 2 of the present invention increases the constant application speed by applying a relative movement of 35.0 Pa to the upper limit by the shear force in the relative movement direction generated in the bead, 2. The stripe coating method according to claim 1, wherein the coating width is reduced to a width equivalent to the width in the nozzle longitudinal direction of the discharge port tip.

  The invention according to claim 3 of the present invention is the stripe coating method according to claim 2, wherein the coating is applied to the surface of the coating member having a plurality of banks provided in parallel at a predetermined pitch. The stripe coating method is characterized in that a constant coating speed is set by applying relative movement so that a coating width applied to each pixel becomes a bank width between the banks.

  According to the first aspect of the present invention, from the result of a later-described coating test in which coating is performed while relatively moving, the coating speed is 2.8 Pa or more and 35.0 Pa or less in terms of shearing force generated in the relative movement direction in the bead. The bead formation is maintained at a constant application speed, and stripe application with a constant application width can be achieved.

  According to the second aspect of the present invention, when a constant coating speed is increased by applying a relative movement of 35.0 Pa to the upper limit by the shearing force generated in the bead in the relative movement direction, a result of a coating test described later. Thus, stripe coating having a coating width equal to the width in the nozzle longitudinal direction of the discharge port tip can be performed.

  According to the third aspect of the present invention, when coating is performed on the surface of the coating member having a plurality of banks provided in parallel with a predetermined pitch using the stripe coating method according to the second aspect, the coating is performed by relatively moving. The constant application speed is set so that the application width applied to the pixels formed between the banks is the bank width between the banks based on the result of the application test using the raw glass. This is a preferred stripe coating method with no overflow.

1 is a perspective view showing a coating apparatus 1 according to an embodiment of the present invention. A nozzle 20 which is a main part of the coating apparatus 1 shown in FIG. 1 is placed on the base 10 and is applied to a member 14 having a plurality of banks provided in parallel to a predetermined pitch. It is the schematic which shows the state of. It is a conceptual diagram showing the state which has applied the nozzle 20 relatively moving at a fixed speed, forming the bead of a coating liquid in a gap.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated in detail with reference to drawings.

  The coating apparatus 1 according to the embodiment of the present invention fills a pixel formed between banks of a predetermined length arranged in parallel with a predetermined pitch on the surface of a member to be applied such as a glass substrate, and dries the coating liquid. Thus, it is used in a process of manufacturing a display panel by forming a stripe-shaped coating film.

  FIG. 1 is a perspective view showing a coating apparatus 1 according to an embodiment of the present invention. As shown in FIG. 1, the coating apparatus 1 includes a base unit 10, a suction stage 13 for mounting and holding a member to be coated 14 on the base unit 10, and a suction stage 13. The stage drive unit 12 is configured to be movable at a predetermined speed in the X-axis direction.

  Here, the direction in which the suction stage 13 moves at a predetermined speed is the X-axis direction, the direction orthogonal to this on the horizontal plane is the Y-axis direction, and the vertical direction orthogonal to the X-axis and Y-axis is the Z-axis direction. .

  A plurality of suction holes (not shown) are provided on the surface of the suction stage 13 and are connected to a suction pump (not shown) via an intake pipe. When the suction pump is operated, the coated member 14 is sucked and held on the surface of the suction stage 13 by the negative pressure.

  Further, in the coating apparatus 1, a coating unit 30 for coating a coating solution on the coating target member 14 is arranged in a gate shape on the base unit 10 so as to straddle the suction stage 13 movable in the X-axis direction. Has been.

  The portal-shaped application unit 30 is configured to support the nozzle 20 that discharges and applies the application liquid to a predetermined position of the member to be coated 14 from above the suction stage 13 so as to support the member to be coated 14. The two column portions 31 on both sides, the beam portion 32 connecting the two column portions at the upper portion of the column portion, and the nozzle 20 is moved up and down in the Z-axis direction and the Y-axis direction substantially at the center of the beam portion 32. The nozzle drive part 21 comprised so that a movement is possible, and the nozzle 20 fixed to the lower part of the nozzle drive part 21 are provided.

  The nozzle drive unit 21 has a height detection means (not shown) for detecting the height from the surface of the member 14 to be applied that is sucked and held by the suction stage 13 and the nozzle 20 at a predetermined position in the Y-axis direction. Alignment adjusting means (not shown) for adjusting the alignment. Based on the height information from the height detection means of the nozzle 20, the nozzle drive unit 21 that moves up and down in the Z-axis direction is controlled by a control device to be described later. It is possible to set the clearance with the surface, that is, the gap (also called clearance), to a predetermined height.

  Further, when applying to the surface of the coating member having a plurality of banks provided in parallel to a predetermined pitch, the center of the nozzle discharge port tip can be aligned and adjusted to the center of the groove between the predetermined bank. It is like that.

  The coating apparatus 1 further includes a coating liquid supply unit 40 that supplies the coating liquid to the nozzle 20. The coating liquid supply unit 40 includes a coating liquid supply pump 41, a coating liquid supply pipe 42, and a coating liquid tank 43, and the coating liquid tank 43 is connected to the nozzle 20 via the coating liquid supply pipe 42.

  A coating liquid supply pump 41 for supplying and supplying the coating liquid is disposed on the coating liquid tank 43 side of the coating liquid supply pipe 42, and the coating liquid is supplied to the nozzle 20 at a predetermined time by being controlled by a control device described later. A predetermined amount can be supplied.

  Furthermore, the operation of each part described above constituting the coating apparatus 1 according to the embodiment of the present invention, that is, the suction fixing of the member 14 to be applied to the suction stage 13, the movement of the nozzle drive unit 21 in the Y-axis direction, the nozzle 20 Related to coating of the coating apparatus 1, such as raising and lowering in the Z-axis direction and setting a predetermined height of the gap clearance, feeding the coating liquid of the coating liquid supply pump 41, and moving the suction stage 13 at a predetermined speed in the X-axis direction. The coating apparatus 1 includes a control device (not shown) that controls a series of operations.

  The control device is composed of a computer including arithmetic means comprising a CPU, storage means such as a ROM, RAM, and HDD for storing programs and data, an input / output interface for inputting and outputting signals to the outside, and the like stored in the storage means The various programs thus executed are executed by the calculation means so that the nozzle 20 can be applied to the application target member 14.

  FIG. 2 shows a case where a nozzle 20, which is a main part of the coating apparatus 1 shown in FIG. 1, is applied to a coated member 14 having a bank which is held on a base 10 and is provided in parallel with a predetermined pitch. FIG.

  As shown in FIGS. 1 and 2, the longitudinal direction of the nozzle 20 is fixed to the nozzle driving unit 21 so as to coincide with the Y-axis direction.

  The nozzle 20 is a column-shaped hollow container-like member having a shape extending long in the longitudinal direction, and a plurality of discharge ports for discharging the coating liquid are predetermined in the Y-axis direction on the side facing the surface of the coated member 14. With a pitch interval of. Each discharge port of the nozzle 20 has a discharge port front end portion 22 formed by protruding the periphery of the discharge port in the coating liquid discharge direction.

  Further, a plurality of banks arranged in parallel at the same pitch as the predetermined pitch of the plurality of discharge ports of the nozzle 20 are applied to the member to be coated 14 disposed in the direction in which the coating liquid is discharged from the discharge port front end portion 22. Pixels formed between them are formed.

  By adjusting the alignment of the nozzle drive unit 21 in the Y-axis direction and raising and lowering in the Z-axis direction, the discharge port front end portion 22 of the nozzle 20 is brought close to the pixel of the member 14 to be coated, and the gap with the pixel of the member 14 to be coated is increased. While maintaining the gap amount at a predetermined height, the coating liquid is supplied from the coating liquid supply unit 40 to the discharge port front end portion 22 of the nozzle 20 to be discharged, and the gap between the discharge port front end portion 22 and the pixel of the coated member 14 After forming the bead of the coating liquid in (gap), when the suction stage 13 that sucks and supports the member 14 to be coated is relatively moved a predetermined length in the X-axis direction perpendicular to the longitudinal direction of the base 20 at a predetermined constant speed, A coating liquid is applied to the pixels of the member to be coated 14.

  The step of drying the coating liquid applied to the pixels of the member 14 to be coated to form a stripe-shaped coating film is completed.

The inventors performed a coating test using the coating device 1 described above.
In the coating test, a 0.7 mm thick glass plate (100 mm × 100 mm) is used as a member to be coated, the coating length is 80 mm, and the coating film thickness before drying is 4 μm.

  The nozzle 20 used in the coating test has a length in the longitudinal direction that can be applied of 30 mm, has 101 discharge ports with a pitch interval of 300 μm, and is formed by protruding in the coating liquid discharge direction around each discharge port. The width in the nozzle longitudinal direction of the discharge port front end portion 22 is 60 μm.

  The purpose of the coating test is to stably form a fine stripe-shaped coating film having a coating width of 100 μm or less. Therefore, the nozzle 20 is not provided on the surface of the raw glass as the member to be coated. The coating solution was applied and dried so as to be a parallel straight line having a coating length of 80 mm with a pitch of 300 μm, and the coating width was measured.

  The coating liquid for organic EL used in the coating test has a viscosity of 0.035 Pa · s.

  If the gap clearance is small, the risk of collision between the discharge port tip 22 and the coated member 14 due to deflection, thickness unevenness, deposits, etc. of the coated member 14 increases, and if the gap clearance is large, it is economical. In the coating test with a viscosity of 0.035 Pa · s, the gap clearance is changed in the range of 70 μm to 40 μm, and the coating speed by moving the suction stage 13 is not possible. Was changed in the range of 4.2 mm / s to 66.8 mm / s, and the coating test was performed.

  Table 1 shows the results of the coating test. In addition, in Table 1, in addition to the test conditions of the above-described coating test, the gap amount of the gap with a coating solution having a different viscosity in the range of 0.005 Pa · s to 0.014 Pa · s for the organic EL coating solution. Is shown together with additional experiment data of 40 μm to 30 μm.

  As shown in Table 1, in the coating test results, the gap clearance was determined from four experimental data in which the gap clearance amount was reduced from 70 μm to 40 μm in the same 16.7 mm / s coating test. When the amount was 60 μm, the coating width was the widest, and when the gap clearance was 40 μm, the coating width tended to approach 100 μm.

  From this, it is considered that the coating width can be reduced to 100 μm or less by further reducing the gap clearance for the coated member 14 having no deposit and small deflection and uneven thickness. There is a need to note that the risk of collision between the portion 22 and the member to be coated 14 increases.

  Furthermore, as shown in Table 1, in the results of the application test, from the six experimental data with the gap gap amount of 60 μm being the same and the application speed being different in the range of 4.2 mm / s to 66.8 mm / s, When the coating speed increases, the tendency of the coating width to decrease is recognized, and the possibility of stably forming a fine stripe-shaped coating film having a coating width of 100 μm or less is found.

  Further, in the result of the coating test, when the gap speed is 60 μm and the coating speed is increased to 66.8 mm / s, a plurality of striped parallel straight lines do not have a constant coating width, and some of them are dotted lines. It became a situation.

  When the gap clearance is 60 μm and the coating speed is lower than 66.8 mm / s, a plurality of stripe-like parallel straight lines are formed with a constant coating width. However, the coating speed is 66 with the same gap clearance of 60 μm. When the speed is increased to 8 mm / s, the striped parallel straight lines do not have a constant coating width, and a part of the strips are becoming dotted lines. This is considered to be because there is an upper limit allowed for the shearing force τ in the direction.

  In FIG. 3, the discharge port tip 22 of the nozzle 20 is brought close to the member to be coated 14 to maintain the gap amount with the stripe-shaped groove of the member to be coated 14 at a predetermined height. This represents a state where the coating liquid is discharged from the discharge port tip 22 to form a bead of the coating liquid in the gap and the nozzle 20 is relatively moved at a constant speed for coating.

  The shearing force τ in the relative movement direction generated in the bead is generally expressed by an equation based on the shear rate and the viscosity of the coating solution, τ = μU / h.

  Here, τ is the shearing force in the relative movement direction generated in the coating liquid, μ is the viscosity of the coating liquid, U is the moving speed (coating speed) of the adsorption stage 13, and h is the gap clearance.

  The results of calculating the shearing force τ represented by the above formula are also shown in Table 1.

  From the value of the shearing force τ shown in Table 1, when the shearing force due to the relatively moving coating speed is small, a plurality of stripe-like parallel straight lines stick to each other between adjacent coating lines, making it impossible to measure the coating width. Also, when the shearing force due to the coating speed exceeds the upper limit value, a plurality of stripe-like parallel straight lines do not have a constant coating width, and some coating widths become narrower and become dotted lines. It became a situation.

  In other words, if the shearing force in the relative movement direction generated in the bead is 2.8 Pa or more, a plurality of striped parallel straight lines can be applied without adhering to each other between adjacent application lines, When the generated shearing force in the relative movement direction was 35.0 Pa or less, a plurality of stripe-like parallel straight lines could be applied with a constant application width.

  That is, it can be said that the preferred application condition for stripe application is that the application speed applied by relative movement is within the range of 2.8 Pa or more and 35.0 Pa or less by the shear force in the relative movement direction generated in the bead.

  Further, as shown in Table 1, when the application speed is increased by relatively moving the upper limit of 35.0 Pa with the shear force in the relative movement direction generated in the bead, the application width becomes the width of the tip of the discharge port. An equivalent thin coating width of 65 μm within 10% with respect to 60 μm was achieved.

  Until now, as shown in Patent Document 4, in a state where a stable bead is formed and applied, a stripe-like shape formed between banks from the width in the nozzle longitudinal direction of the discharge tip portion 22 of the nozzle. It has been said that the coating width becomes larger.

  In addition, when the application width applied by relative movement becomes smaller than the width in the nozzle longitudinal direction of the nozzle outlet, the bead formation is determined to be unstable, and therefore the gap clearance is made smaller. Therefore, it is preferable to return the coating width formed between the banks to the same or slightly larger than the width in the longitudinal direction of the discharge tip 22 of the nozzle so that a stable bead is formed. It was.

  However, from the results of various coating tests, the width of the coating formed between the banks is smaller than the width in the nozzle longitudinal direction of the discharge tip of the nozzle, and the situation where it is determined that the formation of beads is unstable is approached. If the coating speed is within a suitable range, bead formation is maintained by continuing coating at a constant coating speed, and a coating film having a width equivalent to the width in the nozzle longitudinal direction of the discharge port tip can be stably formed. Could be formed.

  This means that when the shearing force due to the coating speed exceeds the upper limit value, the striped parallel straight lines do not have a constant coating width, and some of the coating width becomes narrower and becomes almost dotted. When combined with the phenomenon that has become a situation, because the bead coating liquid on the surface of the coated member is pulled in the coating direction by the shear force in the relative movement direction inside the bead caused by giving a constant coating speed, It was inferred to be balanced with the coating width.

  Therefore, the gap gap amount is made constant without correction adjustment, and the formation of beads is maintained by continuing the application at a constant application speed within a suitable range, which is equivalent to the width in the nozzle longitudinal direction of the discharge tip of the nozzle. A thin coating film up to the coating width can be stably formed.

  As an example using the coating apparatus 1 described above, coating was performed on the surface of the coated member 14 having a plurality of banks 51 provided in parallel at a predetermined pitch.

  The nozzle 20 used in the example has a length of 30 mm in the longitudinal direction as in the coating test, has 101 discharge ports with a pitch interval of 300 μm, and protrudes in the coating liquid discharge direction around each discharge port. The width in the nozzle longitudinal direction of the discharge port tip 22 formed in this way is 60 μm. The coating liquid for organic EL used in the examples has a viscosity of 0.014 Pa · s.

  On the surface of the member to be coated 14 used in the example, a plurality of banks 51 having a height of 2 μm, a width of 20 μm, and a length of 80 mm are provided in parallel at a pitch interval of 100 μm.

  The front end surface of the discharge port front end portion 22 of the nozzle used in the example is opposed and brought close to the center of a pixel (every three columns) having a bank width of 80 μm between the bank 51 and the adjacent bank 51, After forming a bead of coating liquid with a gap amount of 35 μm between the discharge port front end portion 22 and the coated member 14, the nozzle and the coated member are arranged in the X-axis direction perpendicular to the longitudinal direction of the nozzle 20. Stripe coating was carried out by relatively moving at a constant coating speed.

  In this embodiment, the constant coating speed for relatively moving the nozzle 20 and the member to be coated 14 is selected to be 50 mm / s, and the shearing force generated in the bead 52 in the relative movement direction is 20.0 Pa. This is because, based on the result of the application test using the above-described raw glass, the constant application speed at which application can be performed by relative movement is set so that the application width to be applied becomes the bank width between the banks 51. It is.

  The coating thickness obtained by drying after coating was 80 nm, and the coating was applied to the pixels between the banks without overflowing from between the banks 51.

  Similarly, the front end surface of the discharge port front end portion 22 of the nozzle used in the example is opposed to the center of a pixel having a bank width of 65 μm (every three columns) between the bank 51 and the adjacent bank 51, The gap between the discharge port tip 22 and the member 14 to be coated is 40 μm, and after forming a bead of coating liquid, the nozzle and the coating in the X-axis direction perpendicular to the longitudinal direction of the nozzle 20 are formed. Even in the result of performing stripe coating in which the member is moved relative to the member at a constant coating speed of 100 mm / s, there is no overflow from between the banks 51, and the coating is applied to the pixels between the banks 51.

  As described above, the stripe coating method of the present invention is such that the coating speed applied by relative movement is applied in a preferred range of 2.8 Pa or more and 35.0 Pa or less by the shear force in the relative movement direction generated in the bead. , The coating width is set at the discharge tip of the nozzle by applying a constant coating speed by applying a relative movement of 35.0 Pa to the upper limit by the shear force in the relative movement direction generated in the bead. The coating width can be reduced to the same width as the nozzle longitudinal direction.

  Therefore, as in this example, the gap width between the discharge port tip and the member to be coated is set appropriately, and the coating width to be coated is determined from the result of the coating test using the raw glass in advance. A strife coating method in which a constant coating speed is set so as to be relatively moved so as to have a bank width between the banks, and is a suitable stripe coating method in which there is no overflow from between the banks.

  Note that the appropriate gap clearance between the front end of the discharge port and the member to be coated is set based on the situation such as the deflection and thickness unevenness of the member to be coated with stripes, unnecessary deposits, and the like.

  By using the stripe coating method of the present invention, it is possible to provide a display member manufacturing apparatus capable of manufacturing a high-quality display member at low cost.

DESCRIPTION OF SYMBOLS 1 Application | coating apparatus 10 Base part 12 Stage drive part 13 Adsorption stage 14 Application | coating member 20 Nozzle 21 Nozzle drive part 22 Discharge port front-end | tip part 30 Application | coating unit 31 Support | pillar part 32 Beam part 40 Application liquid supply part 41 Application liquid supply pump 42 Application Liquid supply piping 43 Coating liquid tank 51 Bank 52 Bead 53 Discharge port 54 Width in the longitudinal direction of the discharge tip of the nozzle 55 Bank width

Claims (3)

  The nozzle has a plurality of discharge ports in the longitudinal direction, and further has a plurality of discharge port tip portions formed by projecting the periphery of each of the discharge ports from the nozzle in the coating liquid discharge direction. The bead of the coating liquid is formed in the gap between the tip of the discharge port and the member to be coated, facing the surface of the member to be coated in the coating liquid discharge direction and in the vicinity thereof, and then in the direction orthogonal to the longitudinal direction of the nozzle A stripe coating method for coating by moving the nozzle and the member to be coated relative to each other, wherein the gap amount between the tip of the discharge port and the member to be coated is constant, and the coating is performed by moving the nozzle relative to the coating member. A stripe coating method, wherein coating is performed at 2.8 Pa or more and 35.0 Pa or less by a shearing force in a relative movement direction generated in the bead.   A constant coating speed is increased by applying a relative movement of 35.0 Pa to the upper limit by the shearing force generated in the bead in the relative movement direction, and is equivalent to the width in the nozzle longitudinal direction of the nozzle discharge port tip. 2. The stripe coating method according to claim 1, wherein the coating width is reduced to the width.   3. The stripe coating method according to claim 2, wherein the coating is applied to the surface of the coating member having a plurality of banks provided in parallel at a predetermined pitch, and a coating width applied to pixels formed between the banks is between the banks. A stripe coating method characterized in that a constant coating speed is set so as to be relatively moved so as to have a bank width of 2.

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