WO2011033865A1

WO2011033865A1 - Coating device and coating method

Info

Publication number: WO2011033865A1
Application number: PCT/JP2010/062794
Authority: WO
Inventors: 宏晃新畑; 唯史塩崎; 向井　健一; 勇夫一尾; 佐々木　俊幸; 昭宏重山
Original assignee: シャープ株式会社; 芝浦メカトロニクス株式会社
Priority date: 2009-09-18
Filing date: 2010-07-29
Publication date: 2011-03-24
Also published as: JP5470395B2; JPWO2011033865A1

Abstract

Disclosed is a coating device that can stably execute a coating step even if an ink tank is exchanged. The coating device (100) that coats a substrate (90) with a solution by means of an inkjet method is provided with a supply tank (25) that supplies the solution to an inkjet head that includes a nozzle (12), and a first ink tank (21) and a second ink tank (22) that replenish the supply tank (25) with the solution. A common ink ductwork (35) connected to the supply tank (25) is connected to the first ink tank (21) with a first ink ductwork (31) therebetween, and is connected to the second ink tank (22) with a second ink ductwork (32) therebetween. When replenishing the supply tank (25) with the solution from the first ink tank (21), a control device (60) controls a second flow rate adjustment valve (34) so as to interrupt the replenishing of the first ink tank (21) with the solution from the second ink tank (22), and when replenishing the first ink tank (21) with the solution from the second ink tank (22), the control device (60) controls a first flow rate adjustment valve (33) so as to interrupt the replenishing of the supply tank (25) with the solution from the first ink tank (21).

Description

Coating apparatus and coating method

The present invention relates to a coating apparatus and a coating method, and more particularly to a coating apparatus and a coating method for coating a solution on a substrate by an inkjet method. Furthermore, the present invention relates to a coating apparatus and a coating method for forming an alignment film or the like of a liquid crystal panel by an ink jet method.
Note that this application claims priority based on Japanese Patent Application No. 2009-216868 filed on Sep. 18, 2009, the entire contents of which are incorporated herein by reference. .

A liquid crystal panel, which is a component of a liquid crystal display device, has a structure in which a pair of substrates are opposed to each other with a predetermined gap secured. A liquid crystal layer containing liquid crystal molecules is sealed in the gap between the substrates. In addition, an alignment film for aligning liquid crystal molecules is formed on the surfaces of both substrates on the liquid crystal layer side.

This alignment film is formed by applying a solution containing polyimide onto the surface of the substrate. As a method for applying the polyimide solution to the substrate, an inkjet method has been proposed in addition to the spin coating method and the spray method (for example, Patent Documents 1 and 2).

JP 2007-264597 A JP 2006-248102 A

When the alignment film is formed by the inkjet method, the alignment film is applied by discharging a coating liquid (for example, a polyimide solution) from the inkjet coating apparatus onto the surface of the substrate. A coating liquid is supplied from the ink tank to the head of the ink jet coating apparatus. If there is only one ink tank, the ink tank must be replaced when the coating liquid in the ink tank runs out. During the replacement of the ink tank, the coating process for forming the alignment film cannot be executed, so that the throughput for forming the alignment film is reduced.

In order to prevent such a problem from occurring, the present inventor examined the operation of an ink jet coating apparatus provided with two pressurized ink tanks. FIG. 1 is a diagram showing a configuration of an ink jet coating apparatus 1000 studied by the present inventors.

1 is provided with an inkjet head 110 having a nozzle 111 for discharging a coating liquid (for example, a polyimide solution) onto a substrate 190. The inkjet coating apparatus 1000 shown in FIG. Here, the coating liquid is discharged from the nozzle 111 of the inkjet head 110, and an alignment film is formed on the surface of the substrate 190.

The coating liquid supplied to the inkjet head 110 is stored in the first ink tank 121 and the second ink tank 122. The first ink tank 121 and the second ink tank 122 are pressurized tanks, and are connected to the intermediate tank 125 via

ink pipes

131 and 132, respectively. The supply tank (intermediate tank) 125 is connected to the inkjet head 110 via an ink pipe 137. The

ink pipes

131 and 132 are provided with flow rate adjustment valves (electromagnetic valves) 133 and 134, respectively.

In the illustrated inkjet coating apparatus 1000, the coating liquid is supplied from the supply tank 125 to the inkjet head 110, so that the first ink tank 121 or the second ink tank is reduced if the amount of the coating liquid stored in the supply tank 125 decreases. From 122, the supply liquid can be replenished to the supply tank 125.

Furthermore, when the application liquid in the first ink tank 121 runs out, the application liquid can be replenished from the second ink tank 122, so that the first ink tank 121 can be replaced during that time. . Similarly, when the application liquid in the second ink tank 122 runs out, the application liquid can be replenished from the first ink tank 121, so that the second ink tank 122 is replaced during that time. be able to. Therefore, in the ink jet coating apparatus 1000, the coating process for forming the alignment film can be continued even during the replacement of the ink tank, so that the problem of a decrease in throughput can be avoided.

However, the present inventor has found that the following problems occur in the inkjet coating apparatus 1000. That is, while the coating liquid is being supplied from the first ink tank 121 to the supply tank 125, the coating liquid in the second ink tank 122 and the ink pipe 132 may be in a state that does not flow for several hours (a neglected state). There is. At that time, if the solvent is volatilized from the coating liquid in the second ink tank 122, there is a possibility that a change in concentration or a change in viscosity may occur. When switching from the first ink tank 121 to the second ink tank 122, the concentration and viscosity are changed. There is a possibility that the changed coating liquid may be supplied to the supply tank 125. If such an application liquid is ejected by the inkjet head 110 to form an alignment film, the quality and yield may be adversely affected.

The present invention has been made in view of such a point, and a main object thereof is to provide a coating apparatus and a coating method capable of stably performing a coating process even when an ink tank is replaced. .

The coating apparatus according to the present invention is a coating apparatus that applies a solution to a substrate by an inkjet method, an inkjet head including a nozzle that discharges the solution to the substrate, a supply tank that supplies the solution to the inkjet head, The supply tank includes a first ink tank and a second ink tank for replenishing the solution, and the supply tank is connected to a common ink pipe, and the common ink pipe is connected to the common ink pipe via the first ink pipe. A first flow rate adjustment that is connected to the first ink tank and is connected to the second ink tank via a second ink pipe, and that adjusts the flow rate of the solution to the supply tank. A valve is provided, and the second ink pipe has a solution flow rate from the second ink tank to the first ink tank. A second flow rate regulating valve is provided, and the first flow rate regulating valve and the second flow rate regulating valve are connected to a control device that controls each of the first and second flow rate regulating valves, The control device replenishes the supply tank with the solution from the first ink tank by controlling the first flow rate adjustment valve, and the control device controls the second flow rate adjustment valve, The second ink tank replenishes the first ink tank with the solution, and the control device refills the solution from the first ink tank to the supply tank with the second ink tank. When the second flow rate adjusting valve is controlled so as to interrupt the replenishment of the solution to the first ink tank and the solution is replenished from the second ink tank to the first ink tank, And controlling the first flow rate regulation valve to interrupt replenishment of the solution into the supply tank from the tank.
In a preferred embodiment, the first ink tank and the second ink tank are pressurized tanks in which the solution is stored.
In a preferable embodiment, a stage unit that holds the substrate is further provided, the substrate is a glass substrate for a liquid crystal panel, and the solution is a polyimide solution.
An application method according to the present invention is an application method in which a solution is applied to a substrate by an inkjet method, and includes a step of discharging the solution to the substrate using a nozzle and a step of supplying the solution to the nozzle. The step of supplying the solution to the nozzle includes a step (a) of supplying the solution from a first ink tank to a supply tank connected to the nozzle, and a step of sending the solution from the supply tank to the nozzle. The step (a) includes a step (a-1) of moving the solution from the first ink tank to the supply tank, and a second ink tank different from the first ink tank. And (a-2) moving the solution to the first ink tank.
In a preferred embodiment, after the step (a-2) is executed, a step of replacing the second ink tank is executed.
In a preferred embodiment, the step (a-2) is executed at least once each time the application of one of the substrates is completed by the step of discharging the solution to the substrate using the nozzle. .
In a preferred embodiment, the step (a-2) is performed during a wiping operation for wiping the nozzle.
In a preferred embodiment, the first ink tank and the second ink tank are pressurized tanks in which the solution is stored, and the steps (a-1) and (a-2) include the first ink tank and the second ink tank. A first electromagnetic valve provided in a common ink pipe connecting the ink tank and the supply tank; and a second electromagnetic valve provided in an ink pipe connecting the first ink tank and the second ink tank. It is executed by controlling.
In a preferred embodiment, the substrate is a glass substrate for a liquid crystal panel, and an alignment film is formed in a step of discharging to the substrate.

According to the present invention, when replenishing the supply tank connected to the nozzle from the first ink tank with the solution, the step of moving the solution from the first ink tank to the supply tank; and the second ink tank to the first ink Moving the solution to the tank. Therefore, compared with the case where the first ink tank and the second ink tank are used until they are used up, the period in which the solution in the second ink tank is left is shortened. Therefore, the concentration change of the solution in the second ink tank is reduced. And viscosity change can be suppressed. As a result, the application process can be stably performed even when the ink tank is replaced, and thus a thin film (for example, an alignment film) can be formed satisfactorily.

It is a figure for demonstrating the structure of the inkjet coating apparatus 1000. FIG. It is a figure for demonstrating the structure of the coating device 100 which concerns on embodiment of this invention. (A) And (b) is a figure for demonstrating the operation | movement of the ink supply in the coating device 100. FIG. It is a figure which shows typically an example of a structure of the coating device 100 which concerns on embodiment of this invention. (A) And (b) is process drawing explaining the coating method which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, components having substantially the same function are denoted by the same reference numerals for the sake of brevity. In addition, this invention is not limited to the following embodiment.

FIG. 2 schematically shows the configuration of the coating apparatus 100 of the present embodiment. The coating apparatus 100 of the present embodiment is an apparatus (inkjet coating apparatus) that applies a solution to a substrate by an inkjet method.

The coating apparatus 100 of this embodiment includes a head unit 10 including a nozzle 12 that discharges a solution (droplet) to a substrate 90, and a tank unit 20 that supplies the solution to the head unit 10. The head unit 10 includes a head (inkjet head) 11 in which nozzles 12 for discharging a solution are formed on a substrate 90. The tank unit 20 includes a supply tank 25 that supplies a solution to the inkjet head 11, and a first ink tank 21 and a second ink tank 22 that replenish the supply tank 25 with the solution.

The inkjet head 11 is formed with one or a plurality of nozzles 12, and the example shown in FIG. 2 shows a structure in which two heads 11 are accommodated in a head cover 13. The solution (application liquid) discharged from the nozzle 12 is, for example, a polyimide solution. Further, the first ink tank 21 and the second ink tank 22 of the present embodiment are pressurized tanks in which the solution (polyimide solution) is stored. When forming a thin film (for example, an alignment film) using the coating apparatus 100 of this embodiment, the solution discharged from the nozzle 12 is applied to the surface of a substrate (for example, a glass substrate) 90 placed on the stage 52. Applied. The stage 52 can move in the horizontal direction (arrow 51), but the inkjet head 11 can also be configured to be movable.

The solution discharged from the nozzle 12 is supplied from the supply tank 25 of the tank unit 20. When the solution in the supply tank 25 decreases, the solution is replenished from the first ink tank 21. Furthermore, in this embodiment, when the solution is replenished from the second ink tank 22 to the first ink tank 21 and the solution in the second ink tank 22 becomes empty, the second ink tank 22 is replaced with a new one. become.

The supply tank 25 of this embodiment is connected to the inkjet head 11 via an ink pipe 37. The supply tank 25 is connected to a common ink pipe 35. The common ink pipe 35 is connected to the first ink tank 21 and the second ink tank 22 at two branches (31, 32). Specifically, the common ink pipe 35 is connected to the first ink tank 21 via the first ink pipe 31 and is connected to the second ink tank 22 via the second ink pipe 32.

The common ink pipe 35 is provided with a first flow rate adjusting valve 33 for adjusting the flow rate of the solution to the supply tank 25. The second ink pipe 32 is provided with a second flow rate adjustment valve 34 that adjusts the flow rate of the solution from the second ink tank 22 to the first ink tank 21. In other words, the second flow rate adjustment valve 34 is provided in the ink pipe (32) that connects the first ink tank 21 and the second ink tank 22.

The first flow rate adjustment valve 33 and the second flow rate adjustment valve 34 are connected to the control device 60. The first flow rate adjustment valve 33 and the second flow rate adjustment valve 34 of the present embodiment are electromagnetic valves, respectively, and the control device 60 can control the first flow rate adjustment valve 33 and the second flow rate adjustment valve 34, respectively. is there.

The control device 60 replenishes the supply tank 25 with the solution from the first ink tank 21 by controlling the first flow rate adjustment valve 33. Specifically, the control device 60 changes the first flow rate adjustment valve 33 from the closed state to the open state while keeping the second flow rate adjustment valve 34 closed, so that the first ink tank 21 changes to the supply tank 25. A solution is introduced. Further, the control device 60 replenishes the solution from the second ink tank 22 to the first ink tank 21 by controlling the second flow rate adjustment valve 34. Specifically, the control device 60 closes the first flow rate adjustment valve 33 and changes the second flow rate adjustment valve 34 from the closed state to the open state, whereby the first ink is discharged from the second ink tank 22. A solution is introduced into the tank 21.

In the configuration of the present embodiment, the step of moving the solution from the first ink tank 21 to the supply tank 25 and the first ink from the second ink tank 22 within a predetermined period (for example, every time the application of the substrate 90 is completed). Moving the solution to the tank 21. By performing these steps, the period in which the solution in the second ink tank 22 is left is shorter than when the first ink tank 121 and the second ink tank 122 shown in FIG. Therefore, it is possible to suppress a change in the concentration or viscosity of the solution in the second ink tank 22.

Further details will be described with reference to FIGS. 3 (a) and 3 (b). 3A and 3B are block diagrams for explaining the operation of solution supply (ink supply) in the coating apparatus 100 of the present embodiment.

First, as shown in FIG. 3A, the solution is replenished from the first ink tank 21 to the supply tank 25 corresponding to the consumption of the solution in the supply tank 25 (arrow 41). Here, when the solution in the first ink tank 21 is exhausted and then switched to the second ink tank 22, the solution in the second ink tank 22 has not been flowing for several hours, for example (becomes left unattended). Therefore, the solvent of the solution may volatilize, causing a change in concentration or a change in viscosity.

Therefore, as shown in FIG. 3B, when replenishing the supply tank 25 from the first ink tank 21, replenishment of the solution from the first ink tank 21 to the supply tank 25 is interrupted at least once. The solution is replenished from the second ink tank 22 to the first ink tank 21 (arrow 42). Here, using the period during which the application of the substrate 90 is not executed (particularly, the period between the application process of the substrate 90 and the next application process), the second ink tank 22 moves to the first ink tank 21. The solution is replenished (arrow 42). The conditions (number of times, delivery time, interval time, etc.) for sending the solution from the second ink tank 22 to the first ink tank 21 are the solutions (coating solutions) present in the second ink tank 22 and the second ink pipe 32. What is necessary is just to determine by using as an index whether the solution may be denatured (concentration / viscosity change) if left for more than a minute.

According to this embodiment, when supplying a solution to the nozzle 12, the solution is replenished from the first ink tank 21 to the supply tank 25, and the solution is sent from the supply tank 25 to the nozzle 12. It can discharge continuously. That is, since there are a plurality of ink tanks for replenishing the solution in the supply tank 25, the solution is supplied to the supply tank 25 by the first ink tank 21 even when one of the second ink tanks 22 is replaced. It is possible to replenish. Therefore, in the configuration of the present embodiment, the application process by ejection from the nozzle 12 can be continued even if the ink tank needs to be replaced.

The step of moving the solution from the second ink tank 22 to the first ink tank 21 based on the step of moving the solution from the first ink tank 21 to the supply tank 25 (see FIG. 3A) (FIG. 3). How many times (or every few minutes) (see (b)) should be executed is the upper limit of the standing time for the solution (coating liquid) existing in the second ink tank 22 and the second ink pipe 32 (for example, 10 minutes). Of course, within the time when the solution is not denatured by leaving, for example, the step of moving the solution from the second ink tank 22 can be executed in accordance with the end of the application of one substrate. .

Replenishment from the first ink tank 21 to the supply tank 25 (see arrow 41 in FIG. 3A) while executing the flow from the second ink tank 22 (see arrow 42 in FIG. 3B) at least once. Will continue. Then, the storage amount of the solution in the second ink tank 22 decreases, and finally, the storage amount of the solution in the second ink tank 22 disappears or falls below the reference amount to be replaced. Here, in a state in which the solution remains in the first ink tank 21, the second ink tank 22 is supplied during the period of replenishment from the first ink tank 21 to the supply tank 25 (see arrow 41 in FIG. 3A). Exchange. Thereafter, similar steps are executed, and when the solution in the second ink tank 22 runs out again, the second ink tank 22 is replaced again.

In the present embodiment, the first ink tank 21 and the second ink tank 22 are pressurized tanks. However, a flow pump is provided in the coating apparatus 100, and the first ink tank 21 and the second ink tank 22 are provided by the flow pump. The solution may be fluidized. The control device 60 that controls the first flow rate adjustment valve 33 and the second flow rate adjustment valve 34 is, for example, an MPU (micro processor unit), and the control device 60 is constructed by a personal computer (PC). May be. In addition, the control device 60 can be configured to have a built-in program for executing the ink replenishment step of the present embodiment.

Next, an example of the configuration of the coating apparatus 100 of the present embodiment will be further described with reference to FIG. FIG. 4 is a diagram schematically showing an example of the configuration of the inkjet coating apparatus 100 of the present embodiment.

The head unit 10 shown in FIG. 4 includes an inkjet head 11 having nozzles 12 for discharging a solution on a substrate. The head 11 has a surface (discharge surface) on which a solution (droplet) is discharged from the nozzle 12. One head 11 is formed with one or a plurality of nozzles 12. In the example shown in FIG. 4, two heads 11 are formed in the head unit 10.

The inkjet head 11 in the head unit 10 can discharge a solution (coating liquid) from the nozzle 12. When forming an alignment film on the substrate 90, a solution (coating solution) to be used is, for example, a polyimide solution. The solution to be used is changed depending on the film (functional film) formed on the substrate 90. Examples of the film (functional film) formed on the substrate 90 include a resist film, a conductive film, and an insulating film, and a necessary solution for the film is used.

The head unit 10 is connected to the tank unit 20, and a solution (coating liquid) is supplied from the tank unit 20 to the head unit 10. As described above, the tank unit 20 includes the supply tank 25 that supplies the solution to the inkjet head 11, and the first ink tank 21 and the second ink tank 22 that replenish the supply tank 25 with the solution.

The substrate 90 formed with the solution from the nozzle 12 is placed on the stage 52 of the stage unit 50. The stage 52 is provided with lift pins 54 for the substrate 90, and the substrate 90 can be moved by the lift pins 54. The stage unit 50 includes a stage moving mechanism 55 that can move while the substrate 90 is placed on the stage 52. The substrate 90 can be moved directly below the nozzles 12 of the inkjet head 11 by the stage moving mechanism 55 (see arrow 51).

The substrate 90 is, for example, a glass substrate, and the substrate 90 in the present embodiment is a glass substrate for a liquid crystal panel. The substrate 90 may be a mother glass before being cut out to the dimensions of the liquid crystal panel, or may be a glass having the size of the liquid crystal panel after being cut out. Further, the substrate 90 may be an array substrate on which a thin film transistor (TFT) is manufactured (or an intermediate product), or a CF substrate on which a color filter (CF) is formed (or an intermediate product). It may be. The substrate 90 may be a glass substrate, a resin substrate, or another thin plate such as a wafer. In addition, the substrate 90 is not limited to the liquid crystal panel 90, and may be a thin substrate for manufacturing a PDP, an organic EL panel, other flat panel displays, or electronic devices.

In this example, a wiping portion 57 (for example, an elastic blade) for wiping the nozzle 12 of the head 11 is provided. The wiping portion 57 removes a coating liquid (for example, a polyimide solution) remaining on the ejection surface of the inkjet head 11 by wiping. More specifically, if the solution (coating liquid) remains on the discharge surface of the nozzle 12 of the inkjet head 11, the liquid surface of the discharge port (orifice) of the nozzle 12 becomes uneven. The discharged liquid droplet becomes unstable. Therefore, when the previous coating process is completed, the wiping of the nozzle 12 is performed before the next coating process is performed. The wiping portion 57 is not limited to an elastic blade, and a water absorbent sheet that can absorb the coating liquid can also be used. The wiping portion 57 of this embodiment is connected to the stage moving mechanism 55 and can be moved by the stage moving mechanism 55. It is one of preferred embodiments to execute the solution flow (arrow 42) step shown in FIG. 3B in accordance with the period of the wiping operation.

In this embodiment, the head unit 10 and the stage unit 50 are installed in a clean room with a filter. In addition, the coating process of the inkjet coating apparatus 100 can be controlled by a computer (for example, a personal computer) 62 disposed outside the clean room.

In addition, the control device 60 of the present embodiment can also be constructed by a computer 62. In this case, the computer 62 stores the ink replenishment step program of this embodiment, and the solution flow step (for example, see FIGS. 3A and 3B) can be executed by the ink replenishment program. it can. Since such a program can be exchanged through a communication line (for example, a LAN line or an Internet line), it may not be stored in the computer 62. Further, such a program can be stored in a storage medium (for example, a semiconductor memory, an optical recording disk, a hard disk, etc.) and moved.

Next, the coating method of this embodiment will be described with reference to FIGS. 5 (a) and 5 (b). FIGS. 5A and 5B are process diagrams for explaining the coating method of the present embodiment.

First, as shown in FIG. 5A, a substrate 90 to be coated is placed on the stage 52. In the state where this substrate 90 is prepared, if necessary, the inkjet head 11 is wiped using a wiping portion 57 for wiping the nozzle 12, and the solution (coating liquid) remaining on the ejection surface of the nozzle 12 is removed. Wipe off.

Next, as shown in FIG. 5B, a functional film (for example, an alignment film made of polyimide) is formed on the substrate 90 by discharging the solution 16 from the nozzle 12 of the inkjet head 11. Specifically, the substrate 90 disposed on the stage 52 is moved (see arrow 51) to form a functional film in a predetermined region. Note that the functional film may be formed by moving the inkjet head 11 without being limited to the method of moving the substrate 90. Further, when the next film forming process is executed after the formation of the functional film by the ink jet head 11, the state shown in FIG. 5A is obtained again, and then shown in FIG. 5B. The coating process is executed.

According to the coating method of this embodiment, the step of discharging the solution (coating solution) 16 to the substrate 90 using the nozzle 12 and the step of supplying the solution 16 to the nozzle 12 are executed. The step of supplying the solution to the nozzle 12 includes a step (a) of replenishing the supply tank 25 connected to the nozzle 12 with the solution from the first ink tank 21 and a step of sending the solution from the supply tank 25 to the nozzle 12. (B). Further, when the solution is supplied from the first ink tank 21 to the supply tank 25, a step of moving the solution from the first ink tank 21 to the supply tank 25 (see an arrow 41 in FIG. 3A), During the step, the step of moving the solution from the second ink tank 22 to the first ink tank 21 (see the arrow 42 in FIG. 3B) is performed.

Therefore, even if the steps of FIGS. 5A and 5B are repeatedly executed, the storage of the solution in the first ink tank 21 is always kept at a constant level, so the second ink tank 22 is periodically replaced. If this is continued, the solution can be replenished. Therefore, the application process does not have to be interrupted when replacing the ink tank, and a decrease in throughput can be suppressed. Furthermore, the solution in the second ink tank 22 is not allowed to stand for a predetermined time or longer (for example, 10 minutes or longer). Therefore, it is possible to prevent the concentration change or viscosity change of the solution in the second ink tank 22 from occurring. can do. As a result, the application process can be stably performed even when the ink tank is replaced, and thus a thin film (for example, an alignment film) can be formed satisfactorily. Specifically, a decrease in the yield of the alignment film can be suppressed, and consequently an increase in manufacturing cost of the liquid crystal panel can be suppressed.

As mentioned above, although this invention has been demonstrated by suitable embodiment, such description is not a limitation matter and, of course, various modifications are possible.

Although the configuration is essentially different from the technical contents of the embodiment of the present invention, as a related technology, there is a technology disclosed in JP-A-2002-52731. The technique disclosed in this publication relates to an ink jet plotter in a textile printing operation in which a figure or pattern is drawn on a cloth or the like. This ink jet plotter has two ink tanks for replenishing ink in an intermediate tank. However, in this publication, when an alignment film or the like is formed, the solution in one of the ink tanks (22) is made to flow to suppress the change in the concentration or viscosity of the solution, thereby stably applying the solution. The technical idea that the process can be performed is not disclosed, and the inkjet plotter disclosed in the publication is essentially different from the embodiment of the present invention.

Further, it is disclosed in the same publication that ink is replenished alternately from two ink tanks to an intermediate tank. However, if this is used as it is for forming an alignment film, the following problems arise. That is, when the ink is simply replenished alternately from the two tanks, the solutions from the two tanks are mixed in the intermediate tank, and the state of the solution is shaken little by little. Therefore, in the case of applying to a large substrate using an alignment film coating solution (for example, polyimide solution), there may be a problem that the alignment film varies in the plane of the substrate.

On the other hand, in the technique according to the embodiment of the present invention, mixing of the solution in the supply tank 25 can be avoided, that is, by once mixing the solution in the second ink tank 22 in the first ink tank 21. In addition, it is possible to efficiently replace and clean the replenishment ink tank 22 while suppressing a change in the state of the coating liquid (for example, a polyimide solution). As a result, it is possible to suppress variations in the state of the alignment film in the plane of the large substrate.

According to the present invention, it is possible to provide a coating apparatus and a coating method capable of stably performing a coating process even when an ink tank is replaced.

10 head unit 11 head (inkjet head)
12 Nozzle 13 Head cover 16 Solution (Coating solution)
20 Tank unit 21 First ink tank 22 Second ink tank 25 Supply tank 31 First ink pipe 32 Second ink pipe 33 First flow adjustment valve 34 Second flow adjustment valve 35 Common ink pipe 37 Ink pipe 50 Stage unit 52 Stage 54 lift pin 55 stage moving mechanism 57 wiping unit 60 control device 62 computer 90 substrate 100 coating device (inkjet coating device)
1000 Inkjet coating device

Claims

An application apparatus for applying a solution to a substrate by an inkjet method,
An inkjet head including a nozzle that discharges the solution onto the substrate;
A supply tank for supplying the solution to the inkjet head;
A first ink tank and a second ink tank for replenishing the solution to the supply tank;
The supply tank is connected to a common ink pipe;
The common ink pipe is connected to the first ink tank via a first ink pipe, and is connected to the second ink tank via a second ink pipe;
The common ink pipe is provided with a first flow rate adjustment valve for adjusting the flow rate of the solution to the supply tank, and the second ink pipe is provided with the first ink tank from the second ink tank. A second flow rate adjustment valve for adjusting the flow rate of the solution to the
The first flow rate adjustment valve and the second flow rate adjustment valve are connected to a control device that controls each of the first and second flow rate adjustment valves,
The controller replenishes the supply tank with the solution from the first ink tank by controlling the first flow rate regulating valve; and
The control device replenishes the solution from the second ink tank to the first ink tank by controlling the second flow rate adjustment valve;
The control device includes:
When replenishing the solution from the first ink tank to the supply tank, the second flow rate adjustment valve is controlled to interrupt replenishment of the solution from the second ink tank to the first ink tank; And,
When replenishing the solution from the second ink tank to the first ink tank, the first flow rate adjustment valve is controlled so as to interrupt the replenishment of the solution from the first ink tank to the supply tank. An applicator that is characterized.
The coating device according to claim 1, wherein the first ink tank and the second ink tank are pressurized tanks in which the solution is stored.
Furthermore, a stage unit for holding the substrate is provided,
The substrate is a glass substrate for a liquid crystal panel,
The coating apparatus according to claim 1, wherein the solution is a polyimide liquid.
An application method for applying a solution to a substrate by an inkjet method,
Discharging the solution to the substrate using a nozzle;
Supplying the solution to the nozzle,
Supplying the solution to the nozzle comprises:
Replenishing the supply tank connected to the nozzle from the first ink tank with the solution (a);
And (b) delivering the solution from the supply tank to the nozzle,
The step (a)
Moving the solution from the first ink tank to the supply tank (a-1);
And a step (a-2) of moving the solution from a second ink tank different from the first ink tank to the first ink tank.
The coating method according to claim 4, wherein after the step (a-2) is executed, a step of replacing the second ink tank is executed.
6. The step (a-2) is performed at least once each time the application of one substrate is completed by the step of discharging a solution to the substrate using the nozzle. The coating method as described.
The coating method according to claim 4 or 5, wherein the step (a-2) is executed during a wiping operation period for wiping the nozzle.
The first ink tank and the second ink tank are pressurized tanks in which the solution is stored,
The steps (a-1) and (a-2) include a first electromagnetic valve provided in a common ink pipe connecting the first ink tank and the supply tank, and the first ink tank and the first ink tank. The coating method according to claim 4, wherein the coating method is executed by controlling a second electromagnetic valve provided in an ink pipe connecting the two ink tanks.
The substrate is a glass substrate for a liquid crystal panel,
The coating method according to claim 4, wherein an alignment film is formed in the step of discharging to the substrate.