JP2011206715A - Coating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating apparatus which can apply a coating liquid uniformly keeping a flow rate of the coating liquid constant even when the coating liquid is sent to a reciprocatingly moving nozzle by a flexible coating liquid supply tube from a coating liquid storage part.SOLUTION: The coating apparatus includes a plurality of nozzles 23 discharging the coating liquid to a glass substrate, a main scanning direction moving mechanism reciprocating the nozzles 23 in a main scanning direction parallel to the surface of the glass substrate, the flexible coating liquid supply tube 64 for sending the coating liquid from the coating liquid storage part 24 to a plurality of nozzles 23, and a pressure fluctuation absorption mechanism 70 arranged between each nozzle 23 and the coating liquid supply tube 64, moving with the nozzle 23 in an integrated manner, and at the same time, sorbing the pressure fluctuation of the coating liquid passing therethrough.

Description

  The present invention is a coating that applies a coating solution to a substrate such as a glass substrate for an organic EL display device, a glass substrate for a liquid crystal display device, a glass substrate for a PDP, a substrate for a solar cell, a substrate for electronic paper, or a mask substrate for a semiconductor manufacturing apparatus. Relates to the device.

  For example, when manufacturing an active matrix driving type organic EL display device using a polymer organic EL (Electro Luminescence) material, a TFT (Thin Film Transistor) circuit is formed on a glass substrate, and an ITO (anode) is used as an anode. Indium Tin Oxide) electrode forming step, partition wall forming step, flowable material coating step including hole transport material, hole transport layer forming step by heat treatment, flowable material including organic EL material coating step, An organic EL layer forming step by heat treatment, a cathode forming step, and a sealing step by forming an insulating film are sequentially performed.

  When manufacturing such an organic EL display device, the coating liquid is continuously discharged as a coating apparatus that applies a coating liquid such as a fluid material containing a hole transport material or a fluid material containing an organic EL material to a substrate. An apparatus is known in which a plurality of nozzles are moved relative to a substrate in a main scanning direction and a sub-scanning direction to apply a coating solution onto a coating region on the substrate in a stripe shape.

  Patent Document 1 discloses a head moving mechanism that reciprocally moves a coating head having a plurality of nozzles in the main scanning direction, and ejects air between the guide portion and the guide portion extending in the main scanning direction. Thus, there has been proposed a slider that is supported by the guide portion in a non-contact state. In the coating apparatus described in Patent Document 1, air is supplied to the slider via an air supply pipe. In addition, the coating liquid is supplied to a plurality of nozzles in the coating head attached to the slider via a flexible coating liquid supply pipe connected to the coating liquid reservoir.

JP 2009-131735 A

  In such a coating apparatus, the uniformity of the coating film thickness is required. Thus, in order to make the film thickness of the coating liquid uniform, it is necessary to make the flow rate of the coating liquid discharged from the nozzle uniform.

  However, if the coating liquid is supplied to a nozzle that reciprocates at high speed with a plurality of nozzles in the coating head connected to the coating liquid reservoir through a flexible coating liquid supply pipe, the nozzle moves. It is difficult to keep the flow rate of the coating liquid discharged from the nozzle constant due to the deformation of the coating liquid supply pipe and the influence of inertia force applied to the coating liquid in the coating liquid supply pipe.

  The present invention has been made to solve the above-described problems. Even when the coating liquid is fed from the coating liquid reservoir to the reciprocating nozzle by a flexible coating liquid supply tube, the coating liquid is An object of the present invention is to provide a coating apparatus capable of uniformly applying a coating liquid while maintaining a constant flow rate.

  The invention described in claim 1 is a coating apparatus that applies a coating liquid to a substrate, a substrate holding unit that holds the substrate, and a nozzle that discharges the coating liquid to the substrate held by the substrate holding unit. A main scanning direction moving mechanism for reciprocating the nozzle in a main scanning direction parallel to the surface of the substrate, and the substrate holding portion orthogonal to the main scanning direction and parallel to the surface of the substrate. A sub-scanning direction moving mechanism that moves relative to the nozzle in a sub-scanning direction, and a flexible coating liquid supply pipe for feeding the coating liquid from the coating liquid reservoir to the nozzle; And a pressure fluctuation absorbing mechanism that is disposed between the nozzle and the coating liquid supply pipe, moves together with the nozzle, and absorbs pressure fluctuations of the coating liquid passing therethrough. Features.

  According to a second aspect of the present invention, in the first aspect of the invention, the pressure fluctuation absorbing mechanism is in a state of being in communication with the liquid feeding path of the coating liquid communicating with the nozzle and the liquid feeding path of the coating liquid. It is comprised from the T-shaped pipe line provided with the tubular member branched and the edge part closed.

  The invention according to claim 3 is the invention according to claim 1, wherein the pressure fluctuation absorbing mechanism includes a chamber having an opening and communicating with the nozzle, and an elastically deformable thin film disposed in the opening. With.

  According to a fourth aspect of the present invention, in the first aspect of the invention, the pressure fluctuation absorbing mechanism is composed of a soft tube that communicates with the nozzle and is elastically deformed by its internal pressure.

  According to a fifth aspect of the present invention, in the first aspect of the present invention, the pressure fluctuation absorbing mechanism includes a pipe line having a micro-orifice communicated with the nozzle.

  The invention according to claim 6 is the invention according to claim 5, wherein the pressure fluctuation absorbing mechanism has a labyrinth structure.

  A seventh aspect of the present invention is the invention according to any one of the first to sixth aspects, wherein a plurality of the nozzles are arranged at a predetermined pitch in the sub-scanning direction, and the coating liquid supply The pipe and the pressure fluctuation absorbing mechanism are arranged corresponding to each nozzle, and the plurality of coating liquid supply pipes are respectively connected via a pump and a mass flow controller for pumping the coating liquid from the coating liquid reservoir. It is connected.

  According to the first to sixth aspects of the present invention, even when the coating liquid is fed from the coating liquid reservoir to the reciprocating nozzle by the flexible coating liquid supply pipe, the flow rate of the coating liquid It is possible to uniformly apply the coating liquid while maintaining a constant.

  According to the seventh aspect of the present invention, even when the coating liquid is pumped to the plurality of nozzles by the action of the pump, the flow rate of the coating liquid discharged from each nozzle is kept constant and the coating liquid is made uniform. It becomes possible to apply to.

It is a top view of the coating device concerning this invention. It is a front view of the coating device concerning this invention. 4 is a cross-sectional view of the vicinity of a slider 31 in the head moving mechanism 21. FIG. FIG. 4 is a schematic diagram showing a connection relationship between a coating liquid storage unit 24 and a plurality of nozzles 23. 1 is a schematic diagram of a pressure fluctuation absorbing mechanism 70 according to a first embodiment of the present invention. It is a schematic diagram of the pressure fluctuation absorption mechanism 70 which concerns on 2nd Embodiment of this invention. It is a schematic diagram of the pressure fluctuation absorption mechanism 70 which concerns on 3rd Embodiment of this invention. It is explanatory drawing which shows the relationship between a micro orifice and a pressure fluctuation. It is a schematic diagram of the pressure fluctuation absorption mechanism 70 concerning 4th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of a coating apparatus according to the present invention, and FIG. 2 is a front view thereof.

  This coating apparatus is for coating a coating solution on a rectangular glass substrate 100. In more detail, this coating apparatus is made of a volatile solvent (in this embodiment, one of aromatic organic solvents) on a glass substrate 100 for an active matrix driving type organic EL (Electro Luminescence) display device. It is for applying a coating liquid containing a certain 4-methylanisole) and an organic EL material as a light emitting material.

  This coating apparatus includes a substrate moving mechanism 11 for moving the glass substrate 100. As shown in FIG. 2, the substrate moving mechanism 11 includes a substrate holding unit 10 that holds the glass substrate 100 from its back surface. The substrate holding unit 10 is supported by a base 13 that moves along a pair of rails 12 and a turntable 14 disposed on the base 13. For this reason, this board | substrate holding | maintenance part 10 can move in parallel with the surface of the glass substrate 100 in the Y direction shown in FIG. This Y direction is a direction orthogonal to a main scanning direction (X direction in FIG. 1) which is a reciprocating direction of the coating head 20 described later. Hereinafter, this Y direction is also referred to as “sub-scanning direction”. The substrate holding unit 10 is rotatable about an axis that faces in the vertical direction (Z direction in FIG. 1).

  The substrate holding unit 10 includes a heater for heating the glass substrate 100 from below. On the surface of the glass substrate 100, a plurality of application regions each extending in the X direction are arranged and formed in the Y direction at a pitch of, for example, 100 to 150 μm. This application region is formed by, for example, partition walls arranged in the X direction.

  In addition, the coating apparatus includes a pair of left and right imaging units 15 for imaging and detecting an alignment mark (not shown) formed on the glass substrate 100 and imaging a coating locus to be described later. Each of the pair of imaging units 15 is provided with a CCD camera. In addition, the coating apparatus includes a pair of left and right test coating stage units 16 used for the trial coating of the coating locus.

  The coating head 20 that discharges the coating liquid toward the surface of the glass substrate 100 held by the substrate holding unit 10 is main-scanned parallel to the surface of the glass substrate 100 along the pair of guide portions 22 by the head moving mechanism 21. It is reciprocated in the direction (X direction in FIG. 1). In the coating head 20, a plurality of nozzles 23 for continuously discharging the same type of coating liquid are disposed at equal intervals in the sub-scanning direction. In FIG. 1 and FIG. 2, only five nozzles 23 are illustrated for convenience of illustration, but the number of nozzles 23 may be larger or may be one. Further, the arrangement of the nozzles 23 may not be equal as long as it has a predetermined pitch.

  The coating head 20 is connected to the coating liquid storage unit 24 and the air supply source 25 via a supply pipe group 26 in which a later-described air supply pipe and a plurality of later-described coating liquid supply pipes 64 are gathered together. On both sides of the substrate holding unit 10 with respect to the reciprocating movement direction (X direction) of the coating head 20, two liquid receiving portions 17 and 18 that receive the coating liquid from the nozzles 23 in the coating head 20 are disposed. Further, a nozzle pitch adjusting mechanism 19 for adjusting the pitch of the plurality of nozzles 23 in the sub-scanning direction is arranged on the side of one liquid receiving unit 18 in the reciprocating movement direction (X direction) of the coating head 20. It is installed.

  FIG. 3 is a sectional view of the vicinity of the slider 31 in the head moving mechanism 21.

  A slider 31 is slidably disposed on the guide member 22 in the head moving mechanism 21 shown in FIG. A through hole 32 through which the guide member 22 passes is formed in the slider 31. As shown in FIG. 1, air of a constant pressure is supplied to the slider 31 from an air supply source 25 through an air supply pipe included in the supply pipe group 26. For this reason, as shown in FIG. 3, air is jetted between the inner peripheral surface of the through hole 32 and the outer peripheral surface of the guide portion 22. In FIG. 3, the air ejection direction is indicated by an arrow denoted by reference numeral A <b> 1. Thereby, the slider 31 is supported so as to be movable in the main scanning direction while being engaged with the guide portion 22 in a non-contact state.

  Referring to FIG. 1, a pair of pulleys 33 that are rotatable around an axis that faces the Z-axis direction are disposed near both ends of the pair of guide portions 22. An endless synchronous belt 34 is wound around the pair of pulleys 33. One end of the slider 31 is fixed to the synchronization belt 34. On the other hand, the application head 20 described above is fixed to the other end of the slider 31. Therefore, the application head 20 can be reciprocated in the (−X) direction or the (+ X) direction by rotating the synchronous belt 34 clockwise or counterclockwise by driving a motor (not shown). At this time, since the slider 31 can be supported in a non-contact state with respect to the guide portion 22 by the action of the gas described above, the reciprocating movement of the coating head 20 can be made fast and smooth. .

  In this coating apparatus, the head moving mechanism 21 becomes a main scanning direction moving mechanism for moving the coating head 20 in the main scanning direction, and the substrate moving mechanism 11 moves in the sub scanning direction for moving the substrate holding portion in the sub scanning direction. It becomes a mechanism. In this coating apparatus, each time the movement of the coating head 20 in the main scanning direction is completed, the glass substrate 100 is moved in the sub-scanning direction, whereby the coating liquid is applied to the coating region on the surface of the glass substrate 100. Execute. During main scanning of the coating head 20, acceleration or deceleration is completed in the vicinity of the liquid receiving portions 17 and 18, and the coating head 20 is, for example, at a constant speed of about 3 to 5 m per second above the glass substrate 100. Move with.

  FIG. 4 is a schematic diagram showing a connection relationship between the coating liquid reservoir 24 and the plurality of nozzles 23 shown in FIG.

  The coating liquid reservoir 24 described above is connected to a single pump 61 for pumping the coating liquid. This pump is connected to a plurality of mass flow controllers 62 through branch pipes. A plurality of nozzles 23 arranged at equal intervals in the sub-scanning direction in the coating head 20 are each a pressure fluctuation absorbing mechanism 70 which is a characteristic part of the present invention, the flexible coating liquid supply pipe 64 described above, It is connected to the mass flow controller 62 via the electromagnetic opening / closing valve 63.

  Each nozzle 23 and the pressure fluctuation absorbing mechanism 70 are arranged in the coating head 20, and the plurality of nozzles 23 and the pressure fluctuation absorbing mechanism 70 are configured to reciprocate in the main scanning direction as a unit. ing.

  The coating liquid stored in the coating liquid storage unit 24 by the action of the pump 61 is pumped toward the mass flow controller 62. Then, after the flow rate of the coating liquid is adjusted by the mass flow controller 62, the coating liquid is sent to the pressure fluctuation absorbing mechanism 70 via the electromagnetic on-off valve 63 and the flexible coating liquid supply pipe 64. At this time, the coating head 20 is fed by the coating liquid supply pipe 64 due to the deformation of the coating liquid supply pipe 64 due to the reciprocating movement of the coating head 20 at high speed or the influence of the inertial force applied to the coating liquid in the coating liquid supply pipe 64. The pressure of the applied coating liquid fluctuates, and it becomes difficult to keep the flow rate constant. For this reason, the pressure fluctuation absorbing mechanism 70 absorbs the fluctuation in the pressure of the coating liquid, and the flow rate of the coating liquid discharged from each nozzle 23 is constant.

  Next, the configuration of the pressure fluctuation absorbing mechanism 70 will be described. FIG. 5 is a schematic diagram of the pressure fluctuation absorbing mechanism 70 according to the first embodiment of the present invention.

  The pressure fluctuation absorbing mechanism 70 according to the first embodiment has a coating liquid feed path 71 whose one end communicates with the coating liquid supply pipe 64 and the other end communicates with the nozzle 23, and a liquid feeding path for the coating liquid. 71 is formed of a T-shaped pipe line provided with a tubular member 72 which is erected upward in a state where it communicates with 71 and whose upper end is closed by a closing member 73. In this pressure fluctuation absorbing mechanism 70, gas is sealed in a region 74 formed in the upper part of the coating liquid in the tubular member 72. And by this gas volume fluctuation | variation, the pressure fluctuation | variation of a coating liquid can be absorbed.

  That is, when the pressure of the coating liquid supplied to the nozzle 23 increases, as shown in FIG. 5A, the gas sealed in the region 74 formed in the upper part of the coating liquid in the tubular member 72 is compressed. When the volume of the region 74 is reduced and the pressure of the coating liquid supplied to the nozzle 23 decreases, the region formed on the upper part of the coating solution in the tubular member 72 as shown in FIG. The gas sealed in 74 is released, and the volume of the region 74 increases. As a result, the pressure fluctuation absorbing mechanism 70 absorbs the fluctuation in the pressure of the coating liquid, and the flow rate of the coating liquid discharged from each nozzle 23 can be made constant. In FIG. 5, the tubular member 72 is erected upward. However, when the enclosed gas does not affect the liquid feeding path 71, the tubular member 72 is not limited to the upper side, and may be in the lateral direction. It may not be orthogonal to the liquid feeding direction.

  FIG. 6 is a schematic diagram of a pressure fluctuation absorbing mechanism 70 according to the second embodiment of the present invention.

  In the pressure fluctuation absorbing mechanism 70 according to the second embodiment, one end of the pressure fluctuation absorbing mechanism 70 communicates with the coating liquid supply pipe 64, and the other end communicates with the nozzle 23, and an opening is formed in the upper part thereof. In addition, the chamber 75 is provided with a coating liquid reservoir 77 and an elastically deformable thin film 78 disposed in an opening in the chamber 75. In the pressure fluctuation absorbing mechanism 70, the pressure fluctuation of the coating liquid can be absorbed by the action of the elastically deformable thin film 78.

  That is, when the pressure of the coating liquid supplied to the nozzle 23 increases, the thin film 78 expands upward as shown in FIG. 6B, the thin film 78 is recessed downward to reduce the volume of the coating liquid storage portion 77, as shown in FIG. 6 (b). As a result, the pressure fluctuation absorbing mechanism 70 absorbs the fluctuation in the pressure of the coating liquid, and the flow rate of the coating liquid discharged from each nozzle 23 can be made constant.

  As in the embodiment shown in FIG. 6, instead of absorbing pressure fluctuations by the action of the elastically deformable thin film 78 disposed in the opening in the chamber 75, the coating liquid communicating with the coating liquid supply pipe 64 is used. The flow path itself may be constituted by a tube that can be elastically deformed, and the pressure variation of the coating liquid may be absorbed by the elastic deformation of the tube itself.

  FIG. 7 is a schematic diagram of a pressure fluctuation absorbing mechanism 70 according to the third embodiment of the present invention.

  The pressure fluctuation absorbing mechanism 70 shown in FIG. 7A has one end communicating with the coating liquid supply pipe 64 and the other end communicating with the nozzle 23, and a pipe line 81 in which a micro orifice by a partition wall 82 is formed. It is made up of. Further, the pressure fluctuation absorbing mechanism 70 shown in FIG. 7B has one end communicating with the coating liquid supply pipe 64 and the other end communicating with the nozzle 23, and a plurality of partition walls 84 in the inside thereof make a minute labyrinth structure. The pipe 83 is formed with an orifice. In this pressure fluctuation absorbing mechanism 70, the pressure fluctuation of the coating liquid can be absorbed by the action of the micro orifice.

  FIG. 8 is an explanatory diagram showing the relationship between the micro-orifice and the pressure fluctuation. 8A shows the relationship between the inner diameter of the pipe and the flow velocity, and FIG. 8B shows the pressure fluctuation at that time.

  As shown in FIG. 8 (a), when the inner diameter of the pipe line decreases from a certain value and then returns to the original inner diameter again, the average flow rate of the coating liquid passing therethrough is from V1. Once, it becomes V2 earlier than V1, and then becomes V1 again. At this time, the pressure loss of the coating liquid flowing through the pipe line due to the friction between the coating liquid and the inner wall of the pipe line is proportional to the square of the flow velocity. For this reason, by providing a micro-orifice in the pipe line, pressure fluctuations can be absorbed by pressure loss. For this reason, the pressure fluctuation absorbing mechanism 70 absorbs the fluctuation of the pressure of the coating liquid, and the flow rate of the coating liquid discharged from each nozzle 23 can be made constant.

  FIG. 9 is a schematic view of a pressure fluctuation absorbing mechanism 70 according to the fourth embodiment of the present invention.

  The pressure fluctuation absorbing mechanism 70 according to the fourth embodiment includes a plurality of soft tubes 85 whose one end communicates with the coating liquid supply pipe 64 and whose other end communicates with the nozzle 23. A large number of these soft tubes 85 are grouped together by a soft outer tube 86. In this pressure fluctuation absorbing mechanism 70, as in the third embodiment described above, the small diameter soft tube 85 constitutes a micro-orifice, and the pressure fluctuation of the coating liquid is caused by the pipe resistance of the small diameter soft tube 85. Can be absorbed.

  In the coating apparatus having the above-described configuration, when the application of the coating liquid is started, the glass substrate 100 is first held by the substrate holding unit 10. And the alignment mark formed in the glass substrate 100 by the imaging part 15 is detected, the substrate holding | maintenance part 10 moves and rotates based on the detection result, and the glass substrate 100 is in the application | coating start position shown as a continuous line in FIG. Be placed. In this state, discharge of the coating liquid is started from the plurality of nozzles 23 in the coating head 20 and the coating head 20 is moved in the main scanning direction by the head moving mechanism 21.

  Then, the coating liquid is continuously discharged from each of the plurality of nozzles 23 toward the surface of the glass substrate 100 at a constant flow rate, and the coating head 20 continuously moves at a constant speed in the main scanning direction. Then, the coating liquid is applied in stripes to a plurality of linear regions in the coating region of the glass substrate 100. At this time, since the pressure fluctuation of the coating liquid is absorbed by the pressure fluctuation absorbing mechanism 70, the flow rate of the coating liquid discharged from each nozzle 23 can be made constant.

  Then, the coating head 20 moves to a standby position facing the liquid receiving unit 18 indicated by a two-dot chain line in FIGS. 1 and 2, thereby forming a stripe pattern by the coating liquid. When the coating head 20 moves to the standby position, the substrate moving mechanism 11 is driven, and the glass substrate 100 moves in the sub-scanning direction together with the substrate holding unit 10. At this time, in the coating head 20, the coating liquid is continuously discharged from the plurality of nozzles 23 toward the liquid receiving unit 18.

  The above operation is continued until the necessary application operation is completed. When the glass substrate 100 moves to the application end position, the discharge of the application liquid from the plurality of nozzles 23 is stopped, and the application operation of the application liquid to the glass substrate 100 by the application apparatus is completed. The glass substrate 100 that has been coated is transported to another coating apparatus or the like, and coating liquids of two colors other than the coating liquid coated by the coating apparatus are coated. And after a predetermined application | coating process is performed with respect to the glass substrate 100, it combines with another component and an organic electroluminescent display apparatus is manufactured.

DESCRIPTION OF SYMBOLS 10 Substrate holding part 11 Substrate moving mechanism 12 Rail 13 Base 14 Rotating table 15 Imaging part 16 Test application stage part 17 Liquid receiving part 18 Liquid receiving part 19 Nozzle pitch adjusting mechanism 20 Coating head 21 Head moving mechanism 22 Guide part 23 Nozzle 24 Coating liquid reservoir 25 Air supply source 31 Slider 32 Through hole 33 Pulley 34 Synchronous belt 61 Pump 62 Mass flow controller 63 Electromagnetic on-off valve 64 Coating liquid supply pipe 70 Pressure fluctuation absorbing mechanism 71 Liquid feed path 72 Tubular member 73 Closing member 75 Chamber 76 Flow path 77 Storage section 78 Thin film 81 Pipe line 82 Bulkhead 83 Pipeline 84 Bulkhead 85 Soft tube 86 Outer tube 100 Glass substrate

Claims (7)

A coating apparatus for applying a coating liquid to a substrate,
A substrate holder for holding the substrate;
A nozzle for discharging a coating liquid to the substrate held by the substrate holding unit;
A main scanning direction moving mechanism for reciprocating the nozzle in the main scanning direction parallel to the surface of the substrate;
A sub-scanning direction moving mechanism that moves the substrate holder relative to the nozzle in a sub-scanning direction that is orthogonal to the main scanning direction and parallel to the surface of the substrate;
A flexible coating liquid supply pipe for feeding the coating liquid from the coating liquid reservoir to the nozzle;
A pressure fluctuation absorbing mechanism that is disposed between the nozzle and the coating liquid supply pipe, moves integrally with the nozzle, and absorbs pressure fluctuations of the coating liquid passing therethrough;
A coating apparatus comprising: The coating apparatus according to claim 1,
The pressure fluctuation absorbing mechanism is
It is constituted by a T-shaped pipe line provided with a liquid feed path for the coating liquid communicating with the nozzle and a tubular member branched in a state communicating with the liquid feed path for the coating liquid and closed at its end. Coating device. The coating apparatus according to claim 1,
The pressure fluctuation absorbing mechanism is
A chamber having an opening and communicating with the nozzle;
An elastically deformable thin film disposed in the opening;
A coating apparatus comprising: The coating apparatus according to claim 1,
The pressure fluctuation absorbing mechanism is
An applicator comprising a soft tube communicating with the nozzle and elastically deforming by its internal pressure. The coating apparatus according to claim 1,
The pressure fluctuation absorbing mechanism is
An applicator comprising a pipe having a fine orifice communicated with the nozzle. The coating apparatus according to claim 5, wherein
A coating apparatus in which the pressure fluctuation absorbing mechanism has a labyrinth structure. In the coating device in any one of Claims 1 thru | or 6,
A plurality of the nozzles are arranged at a predetermined pitch in the sub-scanning direction, and the coating liquid supply pipe and the pressure fluctuation absorbing mechanism are arranged corresponding to each nozzle,
Each of the plurality of coating liquid supply pipes is connected through a mass flow controller and a pump that pumps the coating liquid from the coating liquid reservoir.

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