JP2006281021A - Filtering device, coater and coating method using the device, and method of manufacturing member for display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filtering device equipped with a filtering means which captures bubbles formed in a coating solution supplying passage to the die thoroughly and removes the bubbles out of the device, and has an excellent capability of removing impurities in the coating solution, being free of coating defects and capable of retaining high precision of the coating thickness for a long period, a coater and a coating method using the device and a method of manufacturing a member for displays utilizing the coating method. <P>SOLUTION: The filtering device has a primary and a secondary chamber separated with a plane filtering material and capable of storing a liquid. The first inflow passage for a liquid to flow into the primary chamber and the first outflow passage for the liquid to flow out of the primary chamber are connected respectively with the primary chamber, and the second outflow passage for the liquid to flow out of the secondary chamber is connected with the secondary chamber. The first outflow passage is connected with the primary chamber at a position including the uppermost point of the primary chamber in the gravity direction, and the second outflow passage is connected with the secondary chamber at a position in the uppermost line within the secondary chamber in the gravity direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is used, for example, in the field of manufacturing color filters for color liquid crystal displays, array substrates for TFTs, optical filters, printed circuit boards, integrated circuits, semiconductors, and the like. A coating apparatus and coating method for forming a coating film while discharging a coating liquid onto a surface of a coated member such as a glass substrate by using the above, and manufacture of display members such as a color filter and an array substrate for TFT using these apparatuses and methods It relates to the improvement of the method.

  For color liquid crystal displays, it is roughly divided into color filters and TFT substrates. A color filter has a fine lattice pattern of three primary colors on a glass substrate. After such a lattice pattern forms a black paint film on the glass substrate, a red, blue, green paint film is formed. Are sequentially formed. Also, a thin resist film is formed on the TFT substrate.

  Therefore, in the manufacture of color liquid crystal display substrates and TFT substrates, coating film formation is performed by coating black, red, blue, and green coating solutions and resist solutions on glass substrates. A process becomes indispensable. In this type of forming process, spinners can be used to easily form uniform coatings, but they have been used a lot. Recently, however, the consumption of expensive coating liquids has been reduced, and the width exceeds 1 m. It has become a decisive factor that it can be easily applied even on glass substrates and can improve productivity, and die coaters are increasingly introduced.

  As an example of this type of die coater, there is a type equipped with a reciprocable table, a coating head (die), and a supply device for supplying a coating liquid to the coating head. (For example, patent document 1).

  The die coater is usually provided with a filtration device for removing foreign substances contained in the coating liquid on the upstream side of the die in order to prevent the formation of coating film projections and foreign substance defects (for example, Patent Document 2). ). Foreign substances contained in the coating liquid include environmental foreign substances mixed from the manufacturing process of the coating liquid, and when the coating liquid is a polymer solution or a polymer precursor solution, foreign substances such as polymer gel and monomer residue insoluble matter, coating In the case where the liquid is a slurry, there may be a particle aggregate or the like or a binder resin (polymer or polymer precursor, precursor when a photosensitive binder is used).

  Filter media usually used for filtering these foreign substances include resin filter media such as polypropylene, polyethylene, and tetrafluoroethylene that are processed into a non-woven fabric to form a disk, or a non-woven fabric that is pleated or wound. Depending on the selection of the filtration diameter, 0.1 to 5 μm of foreign matter can be filtered. In addition, a sintered metal filter using a stainless fiber having a higher Young's modulus than the resin and having no deformation of the filtration part is also suitably used (for example, Patent Document 3).

In addition, air is normally dissolved in the coating solution, and there is a narrow gap such as an orifice in the flow path through which the coating solution flows, or negative pressure is generated by the rapid suction operation of the metering pump that supplies the coating solution to the die. Then, dissolved air may appear and become bubbles. Furthermore, if there is a defect in the seal part of the piping or metering pump, air will also enter from there and become bubbles. There is an air trap that traps these bubbles and excludes them to the outside, and fills the container with a coating solution and eliminates bubbles that accumulate on the top by buoyancy. Similarly, there is a deaeration device as one that excludes bubbles and air dissolved in the coating solution (for example, Patent Document 4).
Further, the filtration device itself is provided with an outlet for discharging the coating liquid on the primary side, that is, the upstream side of the filter medium, to have an air vent function, so that bubbles bubbled up to the filtration device are excluded to the outside. Some have been made (for example, Patent Document 5). However, 100% air bubbles cannot be eliminated with an air vent of a normal filtration device, and when the air bubbles that have passed through the filtration device are directly applied to the substrate, a spot-like portion that is not applied is generated. Furthermore, if bubbles that pass through the filtration device accumulate in the die, streaky coating defects occur, or if the bubble accumulation capacity exceeds a certain level, a change in capacity occurs due to compression when the coating solution is supplied to the die. The timing at which the die discharges the coating liquid at the application start part is delayed, and a problem occurs that the film thickness at the application start part is reduced. Furthermore, in a filtering device using a pleated or roll-shaped filter medium, bubbles coming from the upstream side are easily absorbed into the filter medium, and the absorbed bubbles are discharged downstream to cause a coating defect. On the other hand, when the amount of bubbles absorbed in the filter medium increases, a problem occurs that the film thickness of the coating start portion becomes thin as described above.

Further, as a means for eliminating bubbles, there is a configuration in which a coating liquid outlet is provided in the final die so that bubbles can be removed together with the coating liquid (for example, Patent Document 6). This has the merit that air bubbles can be captured at the end, but the die is subjected to complicated processing to generate a staying portion, and sacrifices the original performance of the die. In addition, there is a problem that sufficient bubbles cannot be captured and eliminated, such that fine bubbles cannot be captured and flow out of the discharge port and applied to the substrate, resulting in spot-shaped bubble defects. If there is a high-performance filtration device that can block the bubbles in the coating liquid, like foreign substances, and exclude them outside, there is no need to add extra equipment to eliminate bubbles, and the performance is reduced due to side effects. Therefore, realization is desired in terms of quality, production cost, and maintainability.
JP-A-6-339656 (5th column 18th line to 7th column 25th line, FIG. 1) JP 2000-334355 A (column 7, line 40 to column 8, line 16, FIG. 2) JP 2002-219396 (3rd column 50th line to 4th column 41st line, 8th column 37th line to 10th column 17th line, FIG. 4) JP 2000-350902 A (3rd column 7th line to 4th column 25th line, FIG. 1) Japanese Patent Laid-Open No. 11-28323 (second column 17th line to third column 5th line, FIG. 1) JP-A-6-339655 (6th column, 22nd line to 8th column, 12th line, FIGS. 6 and 7)

  The present invention has been made based on the above-mentioned circumstances, and the object thereof is not only to completely capture bubbles generated in the coating liquid supply path to the die, but to discharge and remove them to the outside. A filtration device that provides a filtration means excellent in the removal performance of liquid foreign matters, has no coating defects, and can maintain high coating film thickness accuracy over a long period of time, a coating device and a coating method using the same, and It is providing the manufacturing method of the member for a display using this method.

The above object is achieved by the means described below.
The filtration device of the present invention has a primary chamber and a secondary chamber that are separated by a planar filter medium and can store a liquid, a first inflow passage through which liquid flows into the primary chamber, and a primary chamber A first outflow passage through which liquid flows out of the chamber is connected to the primary chamber, and a second outflow passage through which liquid flows out of the secondary chamber is connected to the secondary chamber; The first outflow passage is connected to a position including the highest point in the gravity direction of the primary chamber, and the second outflow passage is connected to a position on a line that is the highest in the gravity direction in the secondary chamber. To do.

  Here, the planar filter medium is disposed so that an angle between a normal line of the filter surface and a horizontal line is 0 to 80 degrees, and the first outflow passage and the second outflow passage are in a downstream direction. The passage cross-sectional center line connecting the center of the passage cross-section seen in the above in the downstream direction forms an angle of 5 to 90 degrees with respect to the horizontal line, and the passage cross-sectional center line is directed upward in the gravity direction toward the downstream direction. It is preferable that a switching device capable of passing / stopping the liquid and a flow rate adjusting valve are further connected to the downstream side of the first outflow passage.

  The coating apparatus according to the present invention is a coating apparatus that applies the coating liquid supplied from the coating liquid supply apparatus through the filtration apparatus to the substrate, the coating liquid supply apparatus that supplies the coating liquid to the filtration apparatus, and the coating liquid. And a recovery device for recovering the coating liquid discharged from the first outflow passage of the filtration device.

  Furthermore, the coating method according to the present invention is a coating method in which a coating solution is supplied from a coating solution supply device to the coating device via the filtering device, and the coating solution is applied to the substrate by the coating device. A part of the coating liquid supplied from the apparatus to the filtration device is discharged from the first outflow passage by a predetermined amount, and then the coating liquid is applied to the substrate by the applicator.

  The method for producing a display member according to the present invention is characterized in that the display liquid is produced by filtering the coating solution with the above-described filtration device.

  Another display member manufacturing method according to the present invention is characterized in that a display member is manufactured by the coating method described above.

  If the filtration device, the coating device, and the coating method according to the present invention are used, a planar filter medium that does not absorb and accumulate bubbles is used, and the highest point in the gravity direction where the most bubbles in the primary chamber on the upstream side in the flow direction accumulate. Since an outflow passage capable of air venting is connected and provided at a position including the air bubbles, bubbles larger than the filtration diameter are blocked by the filter medium and captured 100%, and can be discharged from the outflow passage. Furthermore, since the outflow passage is also provided on the uppermost line of the secondary chamber on the downstream side in the flow direction of the filter medium, all the air in the secondary chamber is easily exhausted, and the gas-liquid at the time of the first liquid passage The replacement can be performed in a short time without changing the posture of the filtration device. In addition, by using a flat filter medium with a fine filtration degree, it is possible to completely capture fine bubbles as well as fine foreign matters, so that it is possible to completely eliminate the coating defects due to foreign matters and bubbles, and there are bubbles in the filtration device. Therefore, a coating film with high film thickness accuracy can be obtained without causing any inconvenience that the supply of the coating liquid at the coating start portion is delayed and the film thickness becomes thin. Further, by connecting a flow rate adjusting valve and a switching device capable of passing / stopping liquid to the downstream side of the first outflow passage attached to the primary chamber, the bubbles accumulated in the primary chamber can be removed at an arbitrary timing, and Since the coating liquid can be discharged while being supplied to the secondary chamber via the flat filter medium, it is possible to continue the production of coating while eliminating the influence of the bubbles over a long period of time by removing the bubbles between the application operations.

  According to the method for manufacturing a display member according to the present invention, the display member is manufactured by using the above-described excellent coating method. Can be manufactured over a long period of time.

  Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic front view of a die coater 1 which is a coating apparatus according to the present invention, FIG. 2 is a schematic front sectional view of the filtration device, FIG. 3 is a schematic plan view of the filtration device according to the present invention, and FIG. FIG. 5 is a schematic plan view of a downstream support member which is one member constituting the filtration device.

  Referring first to FIG. 1, a die coater 1 of the present invention is shown. The die coater 1 includes a base 2, and a pair of guide rails 4 are provided on the base 2. On the guide rail 4, a mounting table for the substrate A as a member to be coated, that is, a stage 6 is arranged. The stage 6 is driven by a linear motor (not shown) and reciprocates freely in the X direction indicated by an arrow in FIG. The upper surface of the stage 6 is a vacuum suction surface made of suction holes, and can hold the substrate A by suction.

  Looking at the center of the base 2, there is a gate-shaped column 10. On both sides of the support column 10, an up-and-down lift unit 70 is provided, and a die 20 that performs coating is attached to the up-and-down lift unit 70.

  The die 20 includes a front lip 22 and a rear lip 24 that extend in a direction perpendicular to the X direction (a direction perpendicular to the paper surface), overlapped in the X direction via shims 32, and are integrally formed by a plurality of connection bolts (not shown). Are combined. A manifold 26 is formed at the center of the die 20, and this manifold 26 also extends in the longitudinal direction of the die 20 (direction orthogonal to the X direction). A slit 28 is formed below the manifold 26 so as to communicate therewith. The slit 28 also extends in the longitudinal direction of the die 20, and the lower end thereof opens at the discharge port surface 36 that is the lowermost end surface of the die 20 to form the discharge port 34. Since the slit 28 is formed by the shim 32, the slit gap (measured in the X direction) is equal to the thickness of the shim 32.

  The vertical lifting / lowering device unit 70 that lifts and lowers the die 20 includes a suspension holding base 80 that holds the die 20 in a suspended form, a lifting base 78 that lifts and lowers the suspension holding base 80, and a guide that guides the lifting base 78 in the vertical direction. 74, and a ball screw 76 that converts the rotational motion of the motor 72 into the linear motion of the lifting platform 78. The vertical lift unit 70 has a pair of left and right so as to support both ends of the die 20 in the longitudinal direction, and each can be lifted and lowered independently, so that the tilt angle with respect to the horizontal in the longitudinal direction of the die 20 can be arbitrarily set. Thereby, the discharge port surface 36 of the die 20 and the substrate A can be made substantially parallel over the longitudinal direction of the die 20. Further, the vertical lift unit 70 can provide a clearance, that is, a clearance of any size between the substrate A on the stage 6 and the discharge port surface 36 of the die 20.

  Further, when the right end portion of the base 2 is viewed in FIG. 1, the wiping unit 90 is mounted on the guide rail 4 so as to be movable in the X direction. In the wiping unit 90, a wiping head 92 having a shape that engages with the periphery of the discharge port 34 of the die 20 is attached to the slider 96 via a bracket 94. The slider 96 is freely moved by the drive unit 98 in the longitudinal direction of the die 20, that is, in a direction orthogonal to the X direction. The drive unit 98 and the tray 100 are fixed on the carriage 102. Since the carriage 102 is on the guide rail 4 and is guided by the guide rail 4 and can freely reciprocate in the X direction by a linear motor (not shown), the entire wiping unit 90 can reciprocate in the X direction. When wiping is performed, the entire wiping unit 90 is moved in the X direction to a position where the wiping head 92 is engaged with the die 20, and the die 20 is lowered and engaged with the wiping head 92. When the driving unit 98 is driven to slide the wiping head 92 in the longitudinal direction of the die 20, the coating liquid and other contaminants remaining in the vicinity of the discharge port 34 of the die 20 can be removed and cleaned. . The removed coating liquid and the like are collected in the tray 100. The tray 100 is connected to a discharge line (not shown) and can discharge and collect a liquid such as a coating liquid accumulated inside. The tray 100 can also be used for collecting a coating solution discharged from the die 20 by air bleeding or the like. The wiping head 92 is preferably an elastic body such as rubber or a synthetic resin so that it can be engaged with the die 20 evenly.

  Further, when viewing the left side of the base 2, a thickness sensor 120 for measuring the thickness of the substrate A is attached to the support base 122. The thickness sensor 120 preferably uses a laser. By measuring the thickness of the substrate A with the thickness sensor 120, the clearance that is the gap between the discharge port surface 36 of the die 20 and the substrate A is always constant for the substrate A of any thickness. be able to.

  Looking again at the die 20, the upstream side of the manifold 26 of the die 20 is always connected to a supply hose 60 connected to the coating liquid supply device 40 via an internal passage (not shown). The coating liquid can be supplied from the coating liquid supply apparatus 40. The coating liquid that has entered the manifold 26 is uniformly widened in the longitudinal direction of the die 20 and is discharged from the discharge port 34 through the slit 28.

  The coating liquid supply device 40 includes a filtration unit 200, a supply valve 42, a syringe pump 50, a suction valve 44, a suction hose 62, and a tank 64 on the upstream side of the supply hose 60. A coating liquid 66 is stored in the tank 64, and a back pressure of an arbitrary magnitude can be applied to the coating liquid 66 by being connected to a pressure air source 68. The coating liquid 66 in the tank 64 is supplied to the syringe pump 50 through the suction hose 62. In the syringe pump 50, a syringe 52 and a piston 54 are attached to the main body 56. Here, the piston 54 can reciprocate freely in the vertical direction by a drive source (not shown). The syringe pump 50 is a constant capacity type pump that fills a syringe 52 having a constant inner diameter with a coating liquid, pushes it out by a piston 54, and supplies a single substrate A to the die 20. When filling the syringe 52 with the coating liquid 66, the suction valve 44 is opened, the supply valve 42 is closed, and the piston 54 is moved downward. When supplying the coating liquid filled in the syringe 52 toward the die 20, the suction valve 44 is closed, the supply valve 42 is opened, and the piston 54 is moved upward so that the piston 54 moves inside the syringe 52. The coating liquid is pushed up and discharged.

  The filtration unit 200 includes a filtration device 202 according to the present invention, a switching valve 240 and a throttle device 242 connected to the upstream side of the filtration device 202. As shown in FIG. 2, the filtering device 202 filters the coating liquid through the filter medium 204 inside and supplies the filtered liquid to the die 20, and at the same time removes bubbles and coating liquid accumulated on the upstream side partitioned by the filter medium 204. The switching valve 240 can be opened / closed at an arbitrary timing, and discharged to the collecting device 250 connected to the downstream side of the switching valve 240 and the expansion device 242. The recovery device 250 includes a suction pump 252 that sucks / discharges air bubbles and coating liquid from the filtration device 202, and a recovery tank 254 that stores the discharged liquid. Although the discharge amount can be adjusted by the suction force of the suction pump 252, the suction pump may be eliminated, the collection tank 254 may be opened to the atmosphere, and the liquid in the filtration device 202 may be discharged using gravity. The expansion device 242 is for adjusting the passage amount of the coating liquid and bubbles by changing the passage area of the liquid such as a needle valve, and while supplying the coating liquid to the die 20 by adjusting the squeezing degree, The flow rate of the coating liquid passing through the expansion device 242 can be changed. The arrangement in which the coating liquid is made to flow from the filtering device 202 in the order of the switching valve 240 and the throttling device 242 prevents bubbles and foreign matters that may be generated in the throttling device 242 from entering the filtering device 202 by the switching valve 240. Although it is possible, the arrangement may be such that the coating liquid flows in the order from the filtering device 202 to the expansion device 242 and the switching valve 240. Further, the expansion device 242 may be an orifice having a coating liquid passage hole having a fixed diameter.

  Note that the linear motor, the motor 72, the coating liquid supply device 40, and the like that are operated by the control signal are all electrically connected to the control device 130. Then, a control command signal is transmitted to each device in accordance with an automatic operation program incorporated in the control device, and a predetermined operation is performed. When changing the conditions, if an appropriate change parameter is input to the operation panel 132, the change parameter is transmitted to the control device 130, and a change in driving operation can be realized. In particular, in the coating liquid supply device 40, the syringe pump 50, the supply valve 42, the suction valve 44, and the switching valve 240 are electrically connected, and the control device 130 receives the electrical signal from the control device 130. Any operation can be performed according to the command. By using the control device 130, the operations of the coating liquid supply device 40, the up / down lifting unit 70, and the stage 6 can be freely controlled, so that the coating film profile at the coating start portion and the coating end portion can be arbitrarily set. The operation of the part can be controlled.

  Referring again to FIG. 2, a schematic front cross-sectional view showing details of the filtration device 202 is shown. The filtration device 202 includes a planar filter medium 204, an upstream support member 224 that sandwiches the filter medium 204 without deformation, a downstream support member 226, and seal materials 210A and B that seal one side of each of the upstream support member 224 and the downstream support member 226. The main body A206 and the main body B208 sandwich the sealing materials 210A and B, respectively. Here, the upstream support member 224 may be omitted, and the filter medium 204 may be directly pressed and sealed with the sealant 210A. The main body A206 and the main body B208 are fastened by a clamp fitting 228, and by this fastening force, a force for sandwiching the filter medium 204, the upstream support member 224, the downstream support member 226, and the sealing materials 210A and B is applied by the main body A206 and the main body B208. , Sealability is ensured. As fastening means other than the clamp fitting 228, there are a bolt, a nut, a vise, and the like. As shown in FIG. 3, a clamp fitting that can be fastened with one touch is preferable. An upstream chamber 218 which is a primary chamber is formed between the main body A 206 and the upstream support member 224, and a downstream chamber 220 which is a secondary chamber is formed between the main body B 208 and the downstream support member 226. An upstream outflow passage 212 is connected to a position including the uppermost point in the gravity direction of the upstream chamber 218, and an inflow passage 216 is connected to a position including the lowermost point. There are a plurality of uppermost points in the gravity direction of the upstream chamber 218, and when these are connected, a line is formed, and the position is indicated by an upstream uppermost point indicating line 234 which is a dotted line. The upstream outflow passage 212 is actually connected to the upstream chamber 218 on the line including the uppermost point in the gravitational direction indicated by the upstream uppermost point indicating line 234, and the connecting portion is connected to the inlet of the upstream outflow passage 212. Forming. On the other hand, the downstream outflow passage 214 is connected in the vertical direction in the downstream chamber 220, that is, on the line that is the highest in the direction of gravity. The position of the uppermost line in the downstream chamber 220 is indicated by a downstream uppermost line indicating line 232 which is a dotted line. Here, the uppermost line in the gravitational direction in the downstream chamber 220 is a downstream side obtained by intersecting a plane that includes a line parallel to the filter surface and is perpendicular to the entire wall surface in the downstream chamber 220. In the set of cut surfaces of the chamber 220, it is a line obtained as a set of uppermost points or lines in each cut surface. Depending on the structure of the downstream chamber 220, it may be a single continuous line or a plurality of discontinuous lines. The downstream outflow passage 214 is actually connected to the downstream chamber 220 on the uppermost line in the direction of gravity indicated by the downstream uppermost line indicating line 232, and the connecting portion forms the inlet of the downstream outflow passage 214. is doing. A switching valve 240 and a throttle device 242 are connected downstream of the upstream outflow passage 212. The bubbles naturally move and accumulate at the uppermost position of the upstream chamber 218 and the downstream chamber 220, that is, the position of the uppermost point in the direction of gravity. It can be easily discharged from the outflow passage 212 and the downstream outflow passage 214.

Here, the shape of the planar filter medium 204 may be any of a circle, a quadrangle, and a pentagon or more, but a circle is preferable because of the ease of manufacturing the filter medium and the filter device and exchanging the filter medium.
The filter used for the filter medium 204 is made of a resin such as polypropylene, polyethylene, or tetrafluoroethylene into a non-woven fabric to form a disk, a sintered metal such as stainless steel, or a powder such as stainless steel. There are sintered metal, porous ceramic, glass fiber, etc., any of which may be used. Filter media with Young's modulus of 200 MPa or more, such as sintered fiber metals such as stainless steel, sintered powder metals such as stainless steel, porous ceramics, etc. The foreign matter and bubbles are captured without changing the pore size of the filter medium, and the dispersion / crushing effect of the polymer gel, the pigment agglomerate and the mixture thereof provides a high-quality coating film free from foreign matter and bubble defects. This is preferable. In addition, the same effect can be expected even when a polymer gel is generated in an abnormal retention portion inside the filtration device 202. The higher the Young's modulus of the filter medium is, the better.

As for the pore diameter of the filter medium, the size of the passing foreign matter and bubbles is determined by the pore diameter, and therefore it is preferable to use a filter medium having a diameter of 0.05 μm or more and 10 μm or less. When the pore diameter is less than 0.05 μm, the pressure loss of the filter medium becomes too high and liquid feeding becomes difficult, and when the pore diameter is larger than 10 μm, the passing foreign substances and bubbles have a size that causes a coating defect. The pore size of the filter medium is more preferably 0.5 μm or more and 6 μm or less. The filter medium pore diameter is a pore diameter obtained from measurement by a bubble point described in JIS K3832.
Since the pressure loss and the liquid holding capacity generated when the coating liquid passes through the filter medium increase in proportion to the thickness of the filter medium, the thickness of the filter medium is preferably 3 mm or less, more preferably 1 mm or less. Since the pressure loss is inversely proportional to the cube of the pore size of the filter medium, the thickness of the filter medium is reduced when the pore diameter is small, and the thickness of the filter medium is increased when the pore diameter is large. It is preferable to adjust the thickness of the filter medium so as to be constant.

As the size of the filter medium 204, it is preferable that the filtration area is large because the flow velocity of the filter medium is small, so that foreign substances and bubbles are easily captured. However, in view of practicality, φ20 to φ300 mm, more preferably φ40 to There is φ120mm. If the diameter is smaller than φ20 mm, the passage flow velocity is too large and the effect of trapping foreign matter / bubbles is greatly reduced. This is not preferable because the filtration area is small and the exchange cycle is shortened. On the other hand, when the diameter is larger than 300 mm, it becomes difficult to evenly distribute the coating liquid to the filter surface, and it becomes difficult to handle the filter medium when the filter medium is exchanged.
Although the filter medium 204 can eliminate bubbles larger than the hole diameter, the filter medium 204 is flat and thin, so that the capacity to hold the bubbles smaller than the hole diameter is pleated or wound (so-called cartridge type). It is much smaller than the filter medium of the above, and when the coating liquid is supplied to the die due to the accumulation of a large amount of bubbles, the capacity changes due to compression, the timing at which the die discharges the coating liquid at the coating start section is delayed, and the coating start section The defect that the film thickness becomes thin does not occur at all. Therefore, it can be said that the planar filter medium has a higher bubble elimination capability in the sense that bubbles are not stored inside than a pleated or roll-shaped (so-called cartridge type) filter medium. Therefore, in order to achieve both high foreign matter removal performance and bubble removal performance, it is necessary to use a planar filter medium.

  Since the filter medium 204 is preferably thin with a thickness of 1 mm or less and low in rigidity, the upstream support member 224 and the downstream support member 226 sandwiching the filter medium 204 are made of a thin and highly rigid metal such as stainless steel, and the pressure of the filter medium 204 is reduced. It is preferable to prevent deformation due to fluctuation or the like. The upstream support member 224 and the downstream support member 226 may have a circular flat plate shape. However, as shown in FIG. 2, either one of the upstream support member 224 and the downstream support member 226 has a concave surface as a surface in contact with the filter medium 204, and the filter medium 204 serves as the upstream support member 224 and the downstream support. Preferably, the member 226 is confined. With this configuration, the portion other than the filter medium 204 coating liquid passage surface is sealed, and there is no foreign matter or bubbles passing through the path passing through the filter medium 204 from the upstream side to the downstream side. The surface of the upstream support member 224 and the downstream support member 226 that faces the coating liquid passage surface of the filter medium 204 may have a small hole of 0.5 to 3 mm provided with a hole area ratio of 10 to 90%. The contact plane having a width of 0.5 to 2 mm may be of any configuration such as linearly crossing or forming a concentric circle, but the coating liquid passage area is increased and deformation of the filter medium 204 is prevented. In order to do so, it is preferable that the contacting portions are appropriately arranged.

  The sealing material 210A may be any material as long as the sealing properties of the upstream support member 224 and the main body A206, and the sealing material 210B is the downstream support member 226 and the main body B208, respectively, but an O-ring having appropriate elasticity, A concentric flat packing or the like is preferable. In particular, a concentric flat packing is more preferable because the staying portion can be minimized by making the shape of the coating liquid passage surface substantially the same as the shape of the coating liquid passage surface of the circular filter medium 204.

As the material used for the sealing materials 210A and B, in consideration of chemical resistance, in addition to synthetic rubber such as silicon rubber, ethylene propylene rubber and perfluoro rubber, soft and easily deformable such as Teflon (registered trademark) and polyethylene. Resins and soft metals such as aluminum are preferred.
The upstream chamber 218, which is the primary chamber, and the downstream chamber 220, which is the secondary chamber provided with the filter medium 204 therebetween, may have any shape such as a cylinder or a cone. It is preferable to increase the volume of the upstream chamber 218 and to be larger than the volume of the downstream chamber 220 so that the average flow velocity in the chamber can be increased in order to eliminate the generation of stagnant foreign matter after filtration. When the large bubbles trapped in the upstream chamber 218 contact the filter medium 204 for a long time, and the surface of the filter medium 204 dries, the coating liquid does not hinder the flow of air, so that the large bubbles easily pass through the filter medium 204. Resulting in. Therefore, the period in which the bubbles that have accumulated above the upstream chamber 218 from the upstream outflow passage 212 are discharged together with the coating liquid is shortened so that the time for the large bubbles to contact the filter medium 204 is shortened as much as possible. It is more preferable to provide a space for accumulating air bubbles upward so as not to come into contact with the surface. Also, as shown in FIG. 4, in order to prevent the large bubbles 230 accumulated above the upstream chamber from contacting the filter medium 204, the length of the upstream chamber 218 in the direction perpendicular to the surface of the filter medium 204 is increased. Further, the filtration device 202 itself is tilted so that the upstream chamber 218 is above the downstream chamber 220, and the inlet of the upstream outlet passage 212 provided at the upper end includes the position of the uppermost point P1 in the gravity direction. In addition, it is preferable that the outflow direction of the coating liquid in the upstream outflow passage 212, that is, the downstream direction is upward. When the upstream outflow passage 212 is viewed in the downstream direction in which the liquid flows and the center of the passage cross section is connected in the downstream direction, a line is formed. This line is referred to as a passage cross section center line. As described above, in order to make the outflow direction of the coating liquid in the upstream outflow passage 212, that is, the downstream direction upward, the passage cross-sectional center line needs to be upward in the gravity direction toward the downstream direction. Regarding the inclination angle of the entire filtration device 202 at this time, the angle θ formed by the normal line of the filtration surface of the filter medium 204 and the horizontal line is preferably 0 to 80 degrees, more preferably 30 to 60 degrees. Here, the horizontal line means a line drawn at right angles to the direction of gravity. If a level using water or the like is placed on this horizontal line, the inclination angle is zero. When the angle θ is smaller than 0 degrees, that is, when the upstream chamber 218 is inclined so as to be lower than the downstream chamber 220, the upstream outflow passage 212 is located at a position including the uppermost point in the gravity direction in the upstream chamber 218. Since the sealing material 210A and the upstream support member 224 are obstructed and the connection cannot be made, there arises a disadvantage that bubbles that are not discharged from the upstream chamber 218 are generated. On the other hand, when the angle is greater than 80 degrees, the liquid flow direction of the downstream outflow passage 214 on the downstream side is downward from the horizontal, and the discharge of air in the downstream chamber does not change the tilt angle of the filtration device 202, that is, the posture. This is because there is an inconvenience that cannot be achieved.

  Further, as described above, the downstream chamber 220 is formed into a conical shape having a small volume in consideration of ease of processing in order to increase the average flow velocity in the chamber, and indicates the uppermost line in the gravitational direction, that is, the downstream uppermost line indication. The downstream outflow passage 214 is connected to a position on the line indicated by the line 232, and the outflow direction of the coating liquid in the passage is directed upward, that is, the passage cross-sectional center line is in the gravity direction toward the downstream direction. It is preferable to face upward. As a result, the coating liquid that has passed through the filter medium 204 flows out from the downstream outflow passage 214 toward the die 20 without stagnation. Also, thanks to this configuration, the first liquid is passed, that is, when there is no liquid such as the coating liquid in the filtering device 202 and there is only air, the liquid such as the coating liquid is flowed to turn the air into the liquid such as the coating liquid. In the gas-liquid replacement to be replaced, the air in the downstream chamber 220 moves along the uppermost line in the gravity direction of the downstream chamber 220 while being pushed by the coating liquid. By simply flowing the coating liquid without changing the angle, that is, the posture, it is easily discharged out of the downstream chamber 220 through the downstream outflow passage 214. The inflow passage 216 connected to the position including the lowest point in the gravity direction of the upstream chamber 218 also has the outflow direction of the coating liquid upward, that is, the passage cross-sectional center line of the inflow passage 216 is directed toward the downstream direction. Since the air flow is directed upward in the direction of gravity, air bubbles in front of the filtration device 202 smoothly enter the filtration device 202, and a unidirectional flow is created from the position of the lowest point of the upstream chamber 218, so that the upstream Retention in the side chamber 218 is also difficult to occur. The connection position of the inflow passage 216 with the upstream chamber 218 may be a place other than the lowest point in the gravitational direction, for example, the central portion, and the inflow direction of the coating liquid may be horizontal. In this case, it is preferable to make the bubbles easily enter the upstream chamber 218 by increasing the flow velocity in the inflow passage 216.

As described above, the upstream outflow passage 212 and the downstream outflow passage 214 have the flow line direction of the coating liquid passing therethrough upward in the gravity direction, that is, the passage cross-sectional center line of each outflow passage is directed in the downstream direction. And upward in the direction of gravity. Specifically, the passage cross-sectional center line of each outflow passage preferably forms an angle of 5 to 90 degrees, more preferably 20 to 80 degrees with respect to the horizontal line, and the downstream direction of the passage cross-section center line is upward. Thus, each outflow passage is provided. If the angle is less than 5 degrees, there is a problem that bubbles do not move when the flow velocity in each passage is small. If the angle is greater than 20 degrees, it is preferable that the bubbles naturally move even when the coating solution is stopped. If the angle is less than 80 degrees, there is an advantage that the location of each passage is not restricted.
The inflow passage 216 also has a flow line direction of the coating liquid in the passage, that is, the passage cross-sectional center line is preferably at an angle of 0 to 80 degrees, more preferably 30 to 60 degrees with respect to the horizontal line, and the passage cross section. Make the downstream direction of the center line upward. As a result, it is possible to efficiently introduce the bubbles into the filtering device 202 in a short time.
Furthermore, the inner diameters of the portions of the upstream outflow passage 212, the inflow passage 216, and the downstream flow passage 214 through which the coating liquid passes are preferably φ1 to φ20 mm, more preferably φ2 to φ8 mm. If it is too small, the flow rate will be high and bubbles will be generated by cavitation. If it is too large, the discharge speed of the bubbles will be small, and if it takes time, the small bubbles on the wall side will not move.

Further, the lower outflow passage 214 is preferably arranged as far as possible from the filtration surface of the filter medium 204. Preferably, the shortest distance L between the filtration surface of the filter medium 204 and the inlet center of the lower outflow passage 214 shown in FIG. 5mm or more. When the coating liquid flows out into the lower outflow passage 214, the maximum suction force acts on the nearest filtration surface. However, if L is smaller than 5 mm, the suction force acting on the filtration surface increases, which is extremely serious. This is because air bubbles accumulated at the uppermost portion of the upstream chamber 218 on the upstream side of the filter medium 202 pass through the filter medium 202 and pass into the downstream chamber 220.
As a means for setting the shortest distance L to 5 mm or more, in addition to placing the inlet of the lower outflow passage 214 at a position of L = 5 mm or more, a shield is provided on the filtration surface near the downstream outflow passage 214, and coating is performed. The shortest distance between the position of the filtration surface through which the liquid actually passes and the inlet of the downstream outflow passage 214 may be increased.

  The material of the main body A206 and the main body B208 may be any material such as a metal such as stainless steel, a resin such as Teflon (registered trademark), polypropylene, etc. as long as it has rigidity and chemical resistance. Stainless steel that can be securely and securely fastened by the metal fitting 228 is preferable. In addition, the surface roughness of the wetted surfaces constituting the upstream chamber 218 and the downstream chamber 220 of the main body A 206 and the main body B 208 is preferably small, and the maximum height Rz is 1 μm or less, more preferably 0.1 μm or less. If it is smaller than this value, the coating liquid hardly adheres and long-term stable use is possible.

  The filtration device 202 may be installed on either the upstream side or the downstream side of the syringe pump 50 that is a metering pump. However, the filtration device 202 is installed on the downstream side of the syringe pump 50 for the purpose of increasing the chance of capturing foreign substances and bubbles. Is more preferable.

  The first liquid using the above filtration device 202 is passed, that is, the liquid such as the coating liquid is not present in the filtration device 202 and there is only air. There are the following two methods for replacing with (gas-liquid replacement).

  In the first method, first, when the suction pump 252 of the recovery device 250 is operated, the switching valve 240 is opened, and the coating solution is supplied to the inflow passage 216 of the filtering device 202, a small amount of coating solution passes through the lower portion of the filter medium 204. As a result, most of the coating liquid flows toward the upstream chamber 218 while being accumulated in the downstream chamber 220 a little, so that the coating liquid gradually accumulates in the upstream chamber 218 from the lower side, and finally the upstream side. Air in the upstream chamber 218 is discharged from the outflow passage 212. When the switching valve 240 is closed when only the coating liquid is discharged from the upstream side outflow passage 212, all the coating liquid passes through the filter medium 204 and flows toward the downstream chamber 220. The coating liquid is stored from the lower side, and finally, all the air in the downstream chamber 220 is discharged from the downstream flow passage 214, and the gas-liquid replacement is completed.

In the second method, when the switching valve 240 is closed and the coating liquid is supplied to the inflow passage 216 of the filtration device 202, the coating liquid is slightly accumulated in the lower portion of the upstream chamber 218, and then passes through the filter medium 204 to the downstream side. The coating solution is sequentially stored from the lower side of the chamber 220. As time passes, the air in the downstream chamber 220 is gradually discharged from the downstream outlet passage 214, and finally all the air in the downstream chamber 220 is discharged from the downstream outlet passage 214 to discharge only the coating liquid. Will come to do. At this time, the switching valve 240 is opened, and the suction pump 252 of the recovery device 250 is operated. As a result, all of the supplied coating liquid flows toward the upstream chamber 218, the coating liquid is stored from the lower side of the upstream chamber 218, and the air in the upstream chamber 218 is gradually removed from the upstream outflow passage 212. Discharge. Finally, when all the air in the upstream chamber 218 is exhausted from the upstream outflow passage 212 and only the coating liquid is discharged from the upstream outflow passage 212, the switching valve 240 is closed, and the gas liquid Replacement is complete.
Next, the elimination of the air bubbles after passing the liquid that completely fills the filtration device 202 is performed as follows.

  First, the suction pump 252 of the recovery device 250 is operated with the switching valve 240 closed. The flow rate of the coating liquid flowing out from the upstream-side outflow passage 212 is adjusted to a desired amount by adjusting the opening of the orifice in advance with a throttle device 242 using a needle valve. At this time, it is necessary to adjust so that the coating liquid flows out from both the upstream outflow passage 212 and the downstream outflow passage 214. This is because if the coating liquid does not flow out from the downstream side outflow passage 214, the coating liquid flows backward from the die 20 and air enters from the downstream side. Next, after a predetermined time when a predetermined amount of coating liquid is supplied from the syringe pump 50 to the filtration device 202 and discharged from the die 20, the switching valve 240 is opened and the coating liquid mixed with bubbles is discharged from the upstream outflow passage 212. To do. After the switching valve 240 is closed after a predetermined time, the supply of the coating liquid from the syringe pump 50 to the filtration device 202 is terminated. The above bubble elimination is not performed during coating, but is always performed before or after coating. Further, the bubble removal may be performed before each application, or may be performed after applying several sheets. Further, the number of coatings may be determined periodically. Appropriately performing this bubble elimination operation can eliminate the coating defects caused by bubbles, and also completely eliminates the problem that the film thickness of the coating start portion caused by the accumulation of bubbles in the upstream chamber 218 becomes thin. Can be eliminated.

  The amount of the coating solution discharged from the upstream side outflow passage 212 for removing bubbles is better, but it is preferably 0.5 to 20 cc, more preferably 1 to 5 cc. The liquid feed rate from the syringe pump 50 to the filtration device 202 when removing bubbles is preferably 1 to 10 cc / s, more preferably 2 to 6 cc / s. If it is smaller than this range, bubbles staying in the horizontal pipe or the like on the upstream side of the filtration device 202 are difficult to eliminate, and conversely if larger, foaming may occur in a narrow part of the pipe.

  The size of bubbles trapped / excluded by the filter device 202 is larger than the filter pore diameter of the filter medium 204. Bubbles smaller than the filter pore diameter of the filter medium 204 and bubbles dissolved in the coating solution cannot be excluded. Therefore, it is preferable to install a device for foaming dissolved bubbles or collecting bubbles that are smaller than the diameter of the filtering pores on the upstream side of the filtering device 202 because the bubble eliminating ability is improved. An apparatus having a function of foaming bubbles or collecting small bubbles includes an orifice having a diameter of 0.5 mm or less.

  In this embodiment, an example is shown in which the recovery device 250 using the suction pump 252 is connected to the downstream side of the upstream outflow passage 212. However, the suction pump is not used with the downstream side from the expansion device 242 being open to the atmosphere. You may do it. In this case, since there is no suction unevenness of the suction pump, it is possible to discharge the coating liquid in which bubbles and bubbles are mixed, and further, the coating liquid from the upstream outflow passage 212 more stably.

  Further, the same effect can be obtained even when the application liquid is supplied to the filtration device 202 by pressurizing the tank 64 without using the syringe pump 50.

  Next, a detailed description will be given of an application method when the above filtration method with bubble elimination is applied to single-wafer application in the die coater 1.

  First, when the origin of each operation unit of the die coater 1 is returned, each moving unit moves to the standby position. That is, the stage 6 moves to the left end of FIG. 1 (a position indicated by a broken line), the die 20 moves to the top, and the wiping unit 90 moves so that the tray 100 is positioned below the die 20. Here, from the tank 64 to the die 20, the coating liquid 66 including the filtration device 202 is already filled, and the operation of discharging the residual air inside the die 20 has already been completed. At this time, the coating liquid supply device 40 is in a state where the syringe 52 is filled with the coating liquid 66, the suction valve 44 is closed, the supply valve 42 is opened, and the piston 54 is in the lowermost position. 20 can be supplied. The suction pump 252 of the recovery device 250 is also started to operate.

  First, lift pins (not shown) are raised on the surface of the stage 6, and the substrate A is placed on the lift pins from a loader (not shown). Next, the lift pins are lowered to place the substrate A on the upper surface of the stage 6 and simultaneously hold it by suction. In parallel with this, the coating liquid supply device 40 is operated to eliminate bubbles accumulated in the bubble filtering device 202 so far, and the vicinity of the discharge port 34 of the die 20 is completely seen with the coating liquid. In order to initialize, a predetermined amount of coating liquid 66 is supplied from the syringe pump 50 to the die 20. At this time, after the supply of the coating liquid 66 from the syringe pump 50 is started, the switching valve 240 is opened, the coating liquid 66 in which bubbles are mixed is sent toward the recovery device 250, and the switching valve is closed after a predetermined time. Thereafter, the coating liquid 66 continues to be supplied to the die 20, and the coating liquid 66 is discharged from the die 20 toward the tray 100. After the supply of the coating liquid 66 is stopped, the wiping unit 90 is moved so that the wiping head 92 is positioned just below the discharge port 34 of the die 20. Then, the die 20 is lowered and the discharge port surface 36 of the die 20 is engaged with the wiping head 92, and then the wiping head is slid in the longitudinal direction of the die 20 to clean the vicinity of the discharge port 34 of the die 20 over the longitudinal direction of the die. To do. After the cleaning is completed, the wiping unit 90 returns to the original place (the right end in FIG. 1).

  When it is confirmed that the wiping unit 90 has moved to the right end of the base 2, the stage 6 on which the substrate A is placed starts to move. At this time, the die 20 is in the wiping position far above the position where application is performed in the vertical direction, while the syringe pump 50 is stopped and stands by. Then, the substrate thickness is measured when the substrate A passes under the thickness sensor 120, and the stage 6 is stopped when the coating start portion of the substrate A reaches just below the discharge port 34 of the die 20. At this time, using the measured thickness data of the substrate A, the vertical lift unit 70 is driven so that the clearance between the discharge port surface 36 of the die 20 and the substrate A, that is, the clearance becomes a predetermined value. Lower. Then, the syringe pump 50 is driven to start discharging the coating liquid 66 from the die 20 after filtering through the filtering device 202. After a certain waiting time, the bead grows to a predetermined size, and then the stage 6 starts to move at a predetermined speed to start application of the coating liquid 66 onto the substrate A to form the coating film C.

  When the position slightly before the application end position of the substrate A comes directly below the discharge port 34 of the die 20, the piston 54 is stopped to stop the supply of the application liquid 66, and then the application end position of the substrate A is set to the die position. When it comes directly below the twenty outlets 34, the vertical lift unit 70 is driven to raise the die 20. As a result, the bead formed between the substrate A and the die 20 is cut off, and the application is completed.

  During this time, the stage 6 continues to operate, stops when it reaches the end point position, releases the suction of the substrate A, raises the lift pins, and lifts the substrate A. At this time, the lower surface of the substrate A is held by an unloader (not shown), and the substrate A is transported to the next step. When the substrate A is delivered to the unloader, the stage 6 lowers the lift pins and returns to the origin position. After returning to the origin position of the stage 6, the wiping unit 90 is moved so that the tray 100 is disposed below the discharge port 34 of the die 20.

  After the movement is completed, the suction valve 44 is opened, the supply valve 42 is closed, the piston 54 is lowered, and the application liquid 66 is filled into the syringe 52. After the filling is completed, the piston 54 is stopped, the suction valve 44 is closed, the supply valve 42 is opened, the next substrate A is waited for, and the same operation is repeated. The bubble removal operation of the filtration device 202 described above may be performed every time one sheet is applied, or may be performed every several to several tens of sheets.

  In addition, as a coating liquid which can apply this invention, a viscosity is 1-100 mPaS, More desirably, it is 1-50 mPaS, Although it is preferable from a coating property that it is Newtonian, it is applicable also to the coating liquid which has thixotropy. In particular, it is effective when a coating solution using a solvent having high volatility such as PGMEA, butyl acetate, ethyl lactate or the like is applied. Specific examples of the coating solution that can be applied include a resist solution, an overcoat material, a column forming material, and the like, in addition to the above-described black matrix for color filter and coating solution for forming RGB color pixels. As a member to be coated which is a substrate, a metal plate such as aluminum, a ceramic plate, a silicon wafer or the like may be used in addition to glass. Further, the coating state and coating speed to be used are 0.1 m / min to 10 m / min, more preferably 0.5 m / min to 6 m / min, the die lip gap is 50 to 1000 μm, more preferably 80 to 200 μm, and the coating thickness. Is 1 to 50 μm, more preferably 2 to 20 μm in a wet state.

Example 1
A non-alkali glass substrate having a thickness of 370 × 470 mm and a thickness of 0.7 mm was washed and then coated using the die coater 1. The die had a length of 370 mm in the longitudinal direction of the discharge port and a gap of 100 μm, and a coating film having a width of 370 mm could be formed on the substrate. The coating speed was 100 mm / s. A syringe pump 50 having an inner diameter of φ16 mm was used. Further, the filtration device 202 was as follows. First, a sintered metal filter having an outer diameter of 90 mm, a sintered pore diameter of 3 μm, and a thickness of 0.5 mm was used as the filter medium 204. As shown in FIG. 5, the downstream support member is made of stainless steel having an outer diameter d1 = φ96 mm and a thickness of 2 mm, and has a recess having d2 = φ90.1 mm and a depth of 0.5 mm for accommodating the sintered metal filter. In addition, as shown in FIG. 5, the portion of the sintered metal filter that contacts the filtration surface is provided with a 2 mm edge on the outer periphery of the recess, and a linear support with a width of h = 1 mm at a portion of d3 = φ86 mm every 45 degrees. The parts were connected. The upstream support member 224 is made of stainless steel having an outer diameter of φ96 mm and a thickness of 2 mm, and the portions that come into contact with the filtration surface of the sintered metal filter are 1 mm wide at portions of φ86 mm every 45 degrees, like the downstream support member 226. A linear support portion was connected and provided. By sandwiching the sintered metal filter with the upstream support member 224 and the downstream support member 226, the sintered metal filter is stored in a sealed state in the recess of the downstream support member 226, and there is no inconvenience such as liquid leakage. It was.

  As the sealing materials 210A and B, a circular packing made of perfluoro rubber having an outer diameter of 96 mm, an inner diameter of 86 mm, and a thickness of 2 mm and having a rubber hardness of 80 degrees was used. The main body A206 and the main body 208B are made of stainless steel, and the surface roughness of the liquid contact portion is finished to a maximum height Rz = 0.1 μm. In the sintered metal filter, the arrangement of the filtration device 202 was determined so that the angle between the normal line of the filtration surface and the horizontal line was 0 degrees, that is, the filtration surface was substantially parallel to the vertical line. Accordingly, the upstream outflow passage 212, the downstream outflow passage 214, and the inflow passage 216 have a circular shape with a passage cross section of φ4 mm viewed in the downstream direction. Further, the liquid stream direction of each passage, that is, the passage section center line is 60 degrees with respect to the horizontal line, and the downstream direction of the passage section center line is upward. The upstream chamber 218 has a cylindrical shape with a diameter of 86 mm and a depth of 20 mm, and the downstream chamber has a 220 cone shape with a bottom surface of 86 mm and a depth of 5 mm. The shortest distance between the filtration surface of the sintered metal filter and the inlet center of the downstream outflow passage 214 was 5.5 mm. An air operated type diaphragm valve was used as the switching valve 240, and a needle valve was used as the expansion device 242. Further, in the recovery device 250, a process pump having a vacuum degree of 6.5 kPa is used as the suction pump 252. When the switching valve 240 is open, half of the coating liquid supplied from the syringe pump 50 to the filtration device 202 is the upstream outlet passage. The opening degree of the needle valve was adjusted so as to go to the recovery device 250 via 212.

  Next, the coating solution was a positive resist used for liquid crystal TFT production, having a solid content concentration of 23% and a viscosity of 5 mPaS. The operating speed of the piston 52 of the syringe pump 50 was set to 1.2 mm / s so that the thickness after vacuum drying was 1.5 μm. First, the die 20 was brought close to the application start portion of the stopped substrate, and the clearance between the discharge port surface 36 of the die 20 and the substrate was set to 150 μm. After setting the clearance, the piston 52 started to operate at 1.2 mm / s. Then, after the waiting time t = 0.1 seconds from the start of the piston operation, the operation of the stage 6 is also started to perform coating, and when the discharge port 34 of the die 20 comes to the position of the glass substrate 465 mm from the substrate end (coating start position). The syringe pump 50 was stopped. Thereafter, when the glass substrate position of 470 mm from the edge of the substrate came directly below the discharge port 34, the die 20 was pulled up to finish coating. After the above application, vacuum drying with an ultimate vacuum of 65 Pa was performed in 27 seconds. After drying, the film thickness distribution in the coating direction was measured with an optical interference type film thickness meter, and the film thickness distribution was checked.

When 100 sheets were continuously applied under the above conditions, it was observed that the film thickness at the coating start part was thinner than before, so 10 cc of the coating solution was supplied from the syringe pump 50 at a speed of 1 cc / s. When the switching valve 240 is opened after 1 second and the switching valve 240 is closed after 6 seconds, the coating liquid mixed with bubbles passes through the tube connected to the upstream outlet 212 of the filtration device 202. Was observed. Thereafter, when application was resumed, it was confirmed that the film thickness at the application start part was restored.
Then, every 50 sheets, 10 cc of coating liquid was supplied from the syringe pump 50 at a speed of 1 cc / s, and after 1 second of supply, the switching valve 240 was opened for 5 seconds and then closed to eliminate bubbles. Even when 1000 sheets were applied, the film thickness did not decrease at the start of application. Furthermore, no defects due to bubbles and foreign matters occurred.

Example 2
A color filter was manufactured using the die coater 1 of Example 1.

  First, after cleaning an alkali-free glass substrate having a thickness of 360 mm × 465 mm and a thickness of 0.7 mm, a black matrix coating solution was applied at a thickness of 10 μm and a clearance of 100 μm between the die and the substrate at 3 m / min. Coating is performed by wiping the vicinity of the die discharge port with silicon rubber having the same shape as the discharge port shape, and then bringing the die close to the coating start portion of the substrate with 100 μm clearance, and a coating solution corresponding to a wet thickness of 10 μm. Was sent from a syringe pump, and the movement of the substrate A was started 0.08 seconds after the start of pumping. In order to finish the application, the discharge of the application liquid from the syringe pump is ended when the die reaches a position 5 mm from the application end position, and when the die reaches the application end position, the die is raised at a speed of 3 m / min. I also went there. As the black matrix coating solution applied at this time, a photosensitive one having a solid content concentration adjusted to 10% and a viscosity adjusted to 10 mPaS using titanium oxynitride as a light shielding material, acrylic resin as a binder, and PGMEA as a solvent, respectively. It was. The tact time for coating was 30 seconds. The coated substrate was vacuum-dried to reach 65 Pa in 30 seconds for 60 seconds, and further dried on a hot plate at 100 ° C. for 10 minutes. Next, after performing exposure, development, and peeling, the substrate is heated on a hot plate at 260 ° C. for 30 minutes to cure, and the pitch is 254 μm in the width direction of the substrate, the pitch is 85 μm in the longitudinal direction of the substrate, the line width is 20 μm, The lattice shape is 4800 (substrate longitudinal direction) × 1200 (substrate width direction), diagonal length is 20 inches (305 mm in the substrate width direction and 406 mm in the substrate longitudinal direction), and the thickness is 1 μm. A black matrix film was prepared. In addition, when the coating thickness was measured before forming the lattice pattern of the substrate coated on the first sheet, it was unevenness of ± 3% or less in both the substrate running direction and the width direction except for 10 mm at the end.

  Next, after wet cleaning, an R color coating solution was applied at a thickness of 20 μm, a clearance between the die and the substrate of 100 μm, a discharge speed of 0.36 cc / s, and a stage moving speed of 3 m / min. The coating solution for R color was a photosensitive solution prepared by mixing an acrylic resin as a binder, PGMEA as a solvent, and Pigment Red 177 as a pigment, mixing them at a solid concentration of 10%, and adjusting the viscosity to 5 mPaS. The coated substrate was vacuum-dried to reach 65 Pa in 30 seconds for 60 seconds, and further dried on a hot plate at 90 ° C. for 10 minutes. Next, exposure, development, and peeling were performed to leave an R color coating film having a thickness of 2 μm only on the R pixel portion, and the plate was heated on a hot plate at 260 ° C. for 30 minutes for curing. Next, on the substrate on which the black matrix and the R color coating film are formed, the coating solution for G color is 20 μm thick, the clearance between the die and the substrate is 100 μm, the discharge speed is 360 cc / s, and the stage moving speed is 3 m / min. After coating, vacuum drying was performed for 60 seconds, which reached 65 Pa in 30 seconds, and then further dried on a hot plate at 100 ° C. for 10 minutes.

  Next, exposure, development, and peeling were performed to leave a G-color coating film having a thickness of 2 μm only on the G-color pixel portion, and curing was performed by heating on a 260 ° C. hot plate for 30 minutes. Furthermore, on the substrate on which the black matrix, R color, and G color coating films are formed, the coating solution for B color is 20 μm thick, the clearance between the die and the substrate is 100 μm, the pump discharge speed is 0.36 cc / s, and the stage is moved. The coating was applied at a speed of 3 m / min, and vacuum drying was performed for 60 seconds to reach 65 Pa in 30 seconds. Next, exposure, development, and peeling were performed to leave a 2 μm-thick B-color coating film only on the B-color pixel portion, and curing was performed by heating on a hot plate at 260 ° C. for 30 minutes. The G-color coating solution is an R-color coating solution and the pigment is Pigment Green 36 and the viscosity is adjusted to 10 mPaS at a solid content concentration of 10%. The B-color coating solution is an R-color coating solution. Pigment Blue 15 having a solid concentration of 10% and a viscosity adjusted to 10 mPaS. All of the R, G, and B color coating solutions are applied by wiping the vicinity of the die outlet with silicon rubber, and then approaching the coating start portion of the substrate where the die is stopped with a clearance of 100 μm, and a wet thickness of 20 μm. The coating solution corresponding to was sent from the syringe pump, and the movement of the substrate A was started 0.13 seconds after the pumping was started. In both cases, the discharge of the coating liquid was finished 6 mm before the application end position, and the die was raised at the application end position to complete the application. The tact time for coating was 30 seconds. The coating quality was satisfactory with no pinholes or foreign matter defects caused by bubbles. For each coating solution, every 10 sheets, 10cc of coating solution is supplied from the syringe pump at a speed of 2cc / s. After 1 second from the start of supply, the switching valve is opened for 3 seconds and then closed to eliminate bubbles. As a result, the film thickness distribution at the coating start portion does not drop every time the number of sheets is increased, and the unevenness in the coating direction and the width direction is ± 3% or less excluding the end 10 mm. It was.

  Finally, ITO was deposited by sputtering. With this manufacturing method, 1000 color filters were produced. The obtained color filter had no coating unevenness, the chromaticity was uniform over the entire surface of the substrate, and the quality was satisfactory.

  For example, in the manufacturing field of color filters for color liquid crystal displays, array substrates for TFTs, optical filters, printed boards, integrated circuits, semiconductors, etc. Can be used to produce a high-quality product that does not cause coating defects or film thickness defects due to foreign matters or bubbles. It is also used for manufacturing display members such as color filters and TFT array substrates that require a highly accurate film thickness distribution.

1 is a schematic front view schematically showing a die coater 1 according to an embodiment of the present invention. It is a schematic front sectional view showing details of a filtration device according to an embodiment of the present invention. It is a schematic plan view of a filtration apparatus. It is a schematic front sectional view in another embodiment of the filtration device of the present invention. It is a schematic plan view of one Example of a downstream support member.

Explanation of symbols

1 Die coater 2 Base 4 Guide rail 6 Stage 10 Prop 20 Die (applicator)
22 Front lip 24 Rear lip 26 Manifold 28 Slit 32 Shim 34 Discharge port 36 Discharge port surface 40 Coating liquid supply device 42 Supply valve 44 Suction valve 50 Syringe pump 52 Syringe 54 Piston 56 Main body
60 Supply hose 62 Suction hose 64 Tank 66 Coating liquid 68 Air pressure source
70 Vertical Lifting Unit 72 Motor 74 Guide 76 Ball Screw 78 Lifting Base 80 Suspension Holding Base 90 Wiping Unit 92 Wiping Head 94 Bracket 96 Slider 98 Drive Unit 100 Tray 102 Carriage 120 Thickness Sensor 122 Supporting Base
130 Control Device 132 Operation Panel 200 Filtration Unit 202 Filtration Device 204 Filter Material 206 Main Body A
208 Body B
210A, B Sealing material 212 Upstream outflow passage 214 Downstream outflow passage 216 Inflow passage 218 Upstream chamber 220 Downstream chamber 230 Bubble 224 Upstream support member 226 Downstream support member 228 Clamp fitting 230 Bubble 232 Downstream uppermost line indicating line 234 Upstream Side uppermost point indicating line 240 switching valve 242 throttle device 250 recovery device 252 suction pump 254 recovery tank A substrate (member to be coated)
C Coating film L Shortest distance between the filtration surface of the filter medium 204 and the center of the inlet of the lower outflow passage 214 P1 The highest point in the direction of gravity θ The angle between the normal line of the filtration surface of the filter medium 204 and the horizontal line

Claims (8)

A primary chamber and a secondary chamber, which are separated by a planar filter medium and can store liquid, have a first inflow passage through which liquid flows into the primary chamber, and a first through which liquid flows out of the primary chamber. Each of the outflow passages is connected to the primary chamber, and the secondary chamber is connected to a second outflow passage through which liquid flows out of the secondary chamber. The first outflow passage is connected to the primary chamber. And a second outflow passage is connected to a position on the uppermost line in the gravitational direction in the secondary chamber. The filtration device according to claim 1, wherein the planar filter medium is arranged such that an angle between a normal line of the filtration surface and a horizontal line is 0 to 80 degrees. The first outflow passage and the second outflow passage are configured such that a passage cross-sectional center line obtained by connecting a center of a passage cross section viewed in the downstream direction in the downstream direction forms an angle of 5 to 90 degrees with respect to a horizontal line, and The filtration apparatus according to claim 1 or 2, wherein the center line is provided so as to be directed upward in the gravity direction toward the downstream direction. The filtration device according to any one of claims 1 to 3, wherein a switching device capable of passing / stopping liquid and a flow rate adjusting valve are further connected downstream of the first outflow passage. The filtration device according to any one of claims 1 to 4, a coating solution supply device that supplies a coating solution to the filtration device, and a coating solution that is supplied from the coating solution supply device via the filtration device is applied to a substrate. An applicator comprising: an applicator; and a recovery device for recovering the coating liquid discharged from the first outflow passage of the filtration device. A coating method in which a coating liquid is supplied from a coating liquid supply device to a coating device via the filtration device according to claim 4 and the coating solution is applied to a substrate by the coating device, the coating device supplying the coating solution from the coating liquid supply device A coating method comprising applying a coating solution to a substrate with a coating device after discharging a predetermined amount of the coating solution supplied to the substrate from the first outflow passage. A display member is produced by filtering a coating solution using the filtration device according to claim 1. A display member is manufactured by the coating method according to claim 6.

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