JP2008161741A - Coating apparatus and coating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To uniformize the film thickness distribution of a coating solution inclusive of a final coating position, which is applied to a member to be coated, easy to adjust and hard to get out of order over a long period of time. <P>SOLUTION: A coating solution supply device 2 is driven while moving a coating solution discharge device 3 in a relatively horizontal direction with respect to the member 13 to be coated placed on a support stand to supply the coating solution to the coating solution discharge device 3 and the coating solution is applied to the member 13 to be coated through the nozzle of the coating solution discharge device 3. This coating apparatus is equipped with the branch pipe 19 communicating on the way of the piping reaching the nozzle of the coating solution discharge device 3, a coating solution suction device 5 for sucking the coating solution from the nozzle through the branch pipe 19 and a control device 6 for starting the sucking operation of the coating solution by the coating solution sucking device 5 when the leading end opening part of the nozzle of the coating solution discharge device 3 reaches the final coating region of the member 13 to be coated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a coating apparatus and a coating method for forming a coating film on a surface of a member to be coated such as a liquid crystal display or a PDP (Plasma Display Panel) with a coating liquid.

2. Description of the Related Art Conventionally, as a coating device, a configuration is disclosed in which a pump is reversely rotated while a slit nozzle is relatively lowered at a coating end position or just before a coating end to suck a coating liquid (for example, a patent) Reference 1).
JP 2002-113411 A

  However, in the conventional coating apparatus, even if the pump is rotated in the reverse direction, since the piping from the pump to the slit nozzle is relatively long, the discharge of the coating liquid from the slit nozzle is immediately stopped by the residual pressure in the piping. Can not. For this reason, it is very difficult to control the thickness of the coating liquid at the coating end position. In addition, in order to reversely rotate the pump in advance in consideration of the residual pressure, it is necessary to consider the influence of various parameters such as the viscosity of the coating liquid and the friction with the inner surface of the pipe, which is substantially impossible. Furthermore, there is a problem that an unreasonable load is applied by rotating the pump in the reverse direction and the product life is short.

  Therefore, the present invention is easy to adjust, is less likely to fail over a long period of time, and can provide a coating apparatus and a coating that can make the film thickness distribution of the coating solution applied to the coated member uniform including the final coating position. It is an object to provide a method.

As a means for solving the above problems, the present invention provides:
While moving the coating liquid discharge device in the horizontal direction relative to the member to be coated placed on the support base, the coating liquid supply device is driven to supply the coating liquid to the coating liquid discharge device, A coating apparatus that applies a coating liquid to the coated member through a nozzle of a coating liquid discharge apparatus,
A branch pipe communicating in the middle of the pipe from the coating liquid discharge device to the nozzle;
A coating liquid suction device for sucking a coating liquid from the nozzle through the branch pipe;
A control device for starting the suction operation of the coating liquid by the coating liquid suction device when the tip opening of the nozzle of the coating liquid discharge device reaches the final coating region of the coated member;
It is set as the structure provided with.

  Here, the final application region is a concept including not only the final end but also the position immediately before it in the region where the tip opening of the nozzle moves on the surface of the member to be applied from the start end to the final end. . In short, if the coating liquid is applied as it is, it is a region where the film thickness becomes large, the speed at which the coating liquid discharge device is moved in the horizontal direction relative to the member to be coated, and the type of coating liquid (particularly, viscosity) Etc., and an appropriate position can be determined by experiments or the like.

  With this configuration, when the coating liquid discharge device reaches the final application region of the member to be coated, the dedicated coating liquid suction device passes through a branch pipe branched in the middle of the pipe from the coating liquid discharge device to the nozzle. Since the coating liquid is sucked, it can be made less susceptible to the residual pressure in the pipe. For this reason, drive sources, such as a pump, and collection members, such as a syringe, used for a coating liquid suction device can be made small and inexpensive. In this case, if a pulse motor or a servo motor is used as the drive source, the suction amount can be finely controlled.

Further, the present invention provides a means for solving the above-described problems,
While moving the coating liquid discharge device in the horizontal direction relative to the member to be coated placed on the support base, the coating liquid supply device is driven to supply the coating liquid to the coating liquid discharge device, A coating apparatus that applies a coating liquid to the coated member through a nozzle of a coating liquid discharge apparatus,
A branch pipe communicating in the middle of the pipe from the coating liquid discharge device to the nozzle;
Opening and closing means that allows the branch pipe to be opened to the outside air;
A control device for opening the branch pipe to the open air by the opening and closing means when the tip opening of the nozzle of the coating liquid discharge device reaches the final coating region of the coated member;
It is set as the structure provided with.

  With this configuration, when the coating liquid discharge device reaches the final application region of the member to be coated, the branch pipe is opened to the outside air by the opening / closing means, so that the coating liquid in the nozzle is covered by the adverse effect of the residual pressure in the pipe. A good application state can be obtained in the final application region without being pushed out to the surface of the application member.

  The opening position of the branch pipe to the atmosphere is preferably below the tip opening of the nozzle of the coating liquid discharge apparatus.

  With this configuration, the siphon effect can be exhibited, and the coating liquid can be sucked smoothly without using a separate drive source.

  More preferably, the opening position of the branch pipe to the atmosphere is adjustable in the vertical direction.

  With this configuration, by adjusting the opening position, the suction force can be set to an appropriate value according to the use situation.

Further, the present invention provides a means for solving the above-described problems,
While moving the coating liquid discharge device in the horizontal direction relative to the member to be coated placed on the support base, the coating liquid supply device is driven to supply the coating liquid to the coating liquid discharge device, A coating method in which a coating liquid is applied to the coated member via a nozzle of a coating liquid discharge device,
When the tip opening of the nozzle of the coating liquid discharge device reaches the final application region of the member to be coated, the nozzle is connected via a branch pipe that communicates with the pipe extending from the coating liquid discharge device to the nozzle. The suction operation of the inner coating liquid is started.

Further, the present invention provides a means for solving the above-described problems,
While moving the coating liquid discharge device in the horizontal direction relative to the member to be coated placed on the support base, the coating liquid supply device is driven to supply the coating liquid to the coating liquid discharge device, A coating method in which a coating liquid is applied to the coated member via a nozzle of a coating liquid discharge device,
The tip opening of the nozzle of the coating liquid discharge device reaches the final coating region of the member to be coated, so that the branch pipe communicating with the pipe extending from the coating liquid discharge device to the nozzle is opened to the atmosphere. It is a thing.

  According to the present invention, since the coating liquid is sucked through the branch pipe branched in the middle of the pipe from the coating liquid discharge device to the nozzle, it is difficult to be affected by the residual pressure in the pipe. As a result, it is possible to use a small and inexpensive coating liquid suction device, and it is possible to reliably suction with a desired suction amount and to have excellent reproducibility.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a schematic explanatory diagram of a coating apparatus according to the present embodiment. The coating apparatus generally includes a coating liquid tank 1, a coating liquid supply apparatus 2, a coating liquid discharge apparatus 3, a support base 4, a coating liquid suction apparatus 5, and a control apparatus 6.

  The coating liquid is stored in the coating liquid tank 1 and can be supplied to the coating liquid supply device 2 at any time. As the coating solution, for example, a glass paste for PDP applied on a glass substrate can be used. However, the present invention is not limited to this, and an appropriate one may be selected from conventionally known various coating liquids according to the type of the member to be coated 13.

  The coating liquid supply device 2 includes a cylindrical first cylinder 7, a first piston 8 that reciprocates while sliding inside the first cylinder 7, and a first drive for driving the first piston 8. And a mechanism 9. The first cylinder 7 is made of glass in order to improve the internal visibility, but may be formed of a metal material such as stainless steel. However, it is necessary to keep the surface roughness small by mirror finishing or the like on the inner surface. Further, as the first drive mechanism 9, a direct acting motor or a servo motor can be used. In the direct acting motor, a screw is formed on the rotation shaft thereof, and the first piston 8 can be directly reciprocated. In the servo motor, the first piston 8 can be reciprocated along the ball screw through a support portion screwed into the ball screw. Here, the inner diameter of the first cylinder 7 is 28 mm. The lead of the screw for reciprocating the first piston 8 is 6 mm.

  The coating liquid supply device 2 is connected to a first pipe 10 extending from the coating liquid tank 1 in the vicinity of the coating liquid tank 1 via a first three-way valve 11. By switching the first three-way valve 11 and moving the first piston 8 in the first cylinder 7, the coating liquid in the coating liquid tank 1 can be sucked into the first cylinder 7. The sucked coating liquid can be discharged to the coating liquid discharge device 3 side.

  The coating liquid discharge device 3 has a conventionally known configuration and applies the coating liquid to a coating member 13 such as a PDP (Plasma Display Panel) mounted on the support base 4 via the slit nozzle 12. 14 (see, for example, JP-A Nos. 2002-113411 and 8-229497). The coating liquid discharge device 3 is moved up and down by a lifting device (not shown).

  The support base 4 is made of, for example, a stone surface plate or the like, and the height of the support base 4 can be adjusted by a support jack 15 that supports four corners of the lower surface. A member to be coated 13 is placed on the support base 4, and the coating liquid supply device 2 is driven while the coating liquid discharge device 3 is translated along the member to be coated 13. A coating solution is applied to the surface of the member 13 to form a coating film 14.

  Similar to the coating liquid supply apparatus 2, the coating liquid suction apparatus 5 includes a cylindrical second cylinder 16, a second piston 17 that reciprocates while sliding inside the second cylinder 16, and the second And a second drive mechanism 18 for driving the piston 17. However, the second cylinder 16 is smaller than that used for the coating liquid supply device 2 and has an inner diameter of 4 mm. The lead of the screw for reciprocating the second piston 17 is 2 mm.

  Thus, the reason why the coating liquid suction device 5 can be made very small as compared with the coating liquid supply device 2 is as follows. That is, the ability required for the coating liquid suction device 5 is to pull back a small amount of coating liquid from the tip opening of the slit nozzle 12 to prevent the coating liquid from remaining on the surface of the member to be coated 13. It is only the suction power that can be. Moreover, the distance from the coating liquid suction device 5 to the tip opening of the slit nozzle 12 can be significantly shortened compared to the conventional one (see, for example, Japanese Patent Application Laid-Open No. 2002-113411 described in the background art) (in the drawing). Although it is difficult to discriminate, it is actually as described above.) Accordingly, the sucked coating liquid is not easily subjected to frictional resistance from the inner peripheral surface of the pipe, and a large force is not required for pulling the second piston 17 by the second drive mechanism 18. Further, unlike the conventional case where the discharge and suction of the coating liquid are used together, a large force required to apply the coating liquid from the slit nozzle 12 is not required. Therefore, as described above, the small coating liquid suction device 5 can be used.

  The coating liquid suction device 5 is connected to the branch pipe 19 through a second three-way valve 20. One end of the branch pipe 19 is connected to a pipe that supplies the coating liquid to the slit nozzle 12 in the vicinity of the coating liquid discharge device 3. The other end of the branch pipe 19 is connected to a waste liquid pot 22 through a U-shaped pipe 21. Thereby, by switching the second three-way valve 20 and moving the second piston 17 in the second cylinder 16, the coating liquid can be sucked into the second cylinder 16 from the slit nozzle 12, and the sucked coating liquid is It can be discharged to the waste liquid pot 22.

  The control device 6 performs switching of the three-way valves 11 and 20, drive control of the drive mechanisms 9 and 18, etc., and supplies the coating solution stored in the coating solution tank 1 to the coating solution discharge device 3 to apply the member 13 to be coated. In the final application region, the coating solution is sucked to prevent a partial increase in film thickness.

  Next, the operation of the coating apparatus having the above configuration will be described.

  First, the member 13 to be coated is disposed on the support base 4. The to-be-coated member 13 is accurately positioned at a predetermined position of the support base 4, or the mounting position is not so much care, and the position is detected by a sensor (not shown) after the mounting and stored as coordinate data. Then, the coating liquid discharge device 3 is moved to a position calculated based on a predetermined position or coordinate data (hereinafter referred to as an initial position), and the tip opening of the slit nozzle 12 is moved to one end side of the member to be coated 13. Opposite the edge. At this time, the first three-way valve 11 is switched, the first piston 8 is moved backward by the drive mechanism, and the coating liquid is sucked into the first cylinder 7 of the coating liquid supply apparatus 2 from the coating liquid tank. When a predetermined amount of coating liquid is sucked into the first cylinder 7, the first piston 8 is stopped.

  Subsequently, the coating liquid discharge device 3 is lowered at the initial position (here, the coating liquid discharge device 3 is lowered, but even if the support base 4 is raised, the support base 4 is raised to The discharge device 3 may be lowered), and the gap between the tip opening of the slit nozzle 12 and the surface of the member to be coated 13 is brought close to a predetermined value (here, 100 μm). Further, the first three-way valve 11 is switched, the first drive mechanism 9 is driven in the reverse direction to advance the first piston 8, and thereby the coating liquid in the first cylinder 7 is supplied to the coating liquid discharge device 3. Then, the coating liquid discharge device 3 is translated along the surface of the member 13 to be coated from the initial position at one end to the final coating position at the other end. Thereby, the coating film 14 is sequentially formed on the surface of the member 13 to be coated.

  When the coating liquid discharge device 3 reaches a position immediately before the end (here, the final immediately preceding position is 5 mm before the final coating position), the supply of the coating liquid from the coating liquid supply device 2 is stopped. Then, at a point of time when a predetermined dimension (3 mm in this case) is moved from the position immediately before the end, the coating liquid suction device 5 is driven, and the suction operation of the coating liquid from the slit nozzle 12 is started. That is, the motor of the second drive mechanism 18 is driven, and the second piston 17 is moved backward. As a result, the coating liquid is sucked into the second cylinder 16 from the slit nozzle 12 via the branch pipe 19. When a certain amount of the sucked coating liquid is accumulated in the second cylinder 16, the second three-way valve 20 is switched, the second drive mechanism 18 is reversed, and the second piston 17 is advanced, whereby the second cylinder 16 is discharged. The discharged coating liquid is collected in the waste liquid pot 22. In addition, the distance from the 2nd cylinder 16 to the slit nozzle 12 is short, and the influence of the frictional resistance which a coating liquid receives from the internal peripheral surface of piping is small. Therefore, at the same time as the driving of the coating liquid supply device 2 is stopped, a suction force can be applied to the coating liquid also at the tip opening of the slit nozzle 12, and the time lag between the suction start time and the time when the suction force actually acts Can be suppressed. Further, since the coating liquid suction device 5 is mainly used for suction of the coating liquid from the slit nozzle 12, the conventional reverse drive is unnecessary except for the periodic discharging operation, and there is little failure and long-term operation. A good driving state can be maintained throughout.

  By the way, the final application region is a region up to a position immediately before the end just before reaching the final application position where the tip opening of the slit nozzle 12 is the final end. The position immediately before the end is set as a limit position where the film thickness increases when the coating liquid is continuously supplied beyond this position. Further, this position may be determined as follows, for example, by experiment.

  That is, before the tip opening of the slit nozzle 12 reaches the final application position, the position where the supply of the application liquid from the application liquid supply device 2 is stopped and the position where the application liquid is started to be sucked are changed. Observe the formation state. And based on the result, the position where the coating film 14 having the most appropriate film thickness is obtained is determined as the position immediately before the end. The experimental results are stored as a database, and if there are similar conditions from the next application, the position immediately before the end may be determined based on the stored past data. In addition, the position immediately before the end may be determined by repeating the experiment while adjusting the suction amount of the coating liquid per unit time.

  At the same time as the suction of the coating liquid is started, it is preferable that the coating liquid discharge device 3 is gradually lowered so that the tip opening of the slit nozzle 12 approaches the surface of the member to be coated 13. And it should just make it approach most at the last application position (for example, 70 micrometers). This makes it possible to stabilize the film thickness of the coating film 14 in the final application region on the surface of the member 13 to be applied, and to make it uniform with other parts.

  By the way, in order to replace the suction of the coating liquid performed by the coating liquid suction apparatus 5 with the coating liquid supply apparatus 2 as in the prior art, it is necessary to reversely rotate the motor. When the suction amount is 0.2 cc, the piston stroke (suction stroke) must be 0.32 mm, and the rotation speed of the motor for obtaining the suction stroke must be 0.053. On the other hand, according to the coating liquid suction device 5, when the suction amount is 0.2 cc, the suction stroke is 16.7 mm, and the rotation speed of the motor for obtaining this suction stroke is 8.35. Thus, a necessary amount of coating liquid can be sucked from the slit nozzle 12. For example, if an error of 1/100 rotation occurs in the rotation speed of the motor, it will appear as an error in the suction amount that cannot be ignored by the former conventional method, so it is necessary to control the rotation of the motor with high accuracy, which is expensive. However, if the latter is related to this embodiment, the error range can be neglected, and it is possible to cope with an inexpensive configuration.

(Second Embodiment)
FIG. 2 shows a coating apparatus according to the second embodiment. This coating apparatus is different from that according to the first embodiment in that the coating liquid suction apparatus 5 is not provided. In the second embodiment, descriptions of parts other than those different from the first embodiment are omitted.

  In FIG. 2, instead of the coating liquid suction device 5, the tip of the branch pipe 19 is indicated by a predetermined dimension (A in FIG. 2) than the coating position, that is, the position of the tip opening of the slit nozzle 12 that is coating. ) It is positioned below and opened to the atmosphere. An on-off valve 23 is provided in the middle of the branch pipe 19. Thereby, the coating liquid is sucked from the slit nozzle 12 by the siphon principle only by opening the opening / closing valve 23, and the film of the coating film 14 at the final coating position of the member to be coated 13 is the same as in the first embodiment. It is possible to prevent the thickness from increasing.

  The tip position of the branch pipe 19 may be adjustable in the vertical direction. This position adjustment may be performed based on a suction amount variation parameter such as the type of coating liquid used and the distance from the open position to the coating position. Moreover, you may make it provide the structure which can raise / lower automatically based on this suction amount fluctuation | variation parameter.

It is a schematic explanatory drawing of the coating device which concerns on 1st Embodiment. It is the schematic which shows the support stand part of the coating device which concerns on 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Coating liquid tank 2 ... Coating liquid supply apparatus 3 ... Coating liquid discharge apparatus 4 ... Support stand 5 ... Coating liquid suction apparatus 6 ... Control apparatus 7 ... 1st cylinder 8 ... 1st piston 9 ... 1st drive mechanism 10 ... 1st DESCRIPTION OF SYMBOLS 1 piping 11 ... 1st three-way valve 12 ... slit nozzle 13 ... coated member 14 ... coating film 15 ... support jack 16 ... 2nd cylinder 17 ... 2nd piston 18 ... 2nd drive mechanism 19 ... branch pipe 20 ... 2nd 3 way Valve 21 ... U-shaped tube 22 ... Waste liquid pot 23 ... Open / close valve

Claims (6)

While moving the coating liquid discharge device in the horizontal direction relative to the member to be coated placed on the support base, the coating liquid supply device is driven to supply the coating liquid to the coating liquid discharge device, A coating apparatus that applies a coating liquid to the coated member through a nozzle of a coating liquid discharge apparatus,
A branch pipe communicating in the middle of the pipe from the coating liquid discharge device to the nozzle;
A coating liquid suction device for sucking a coating liquid from the nozzle through the branch pipe;
A control device for starting the suction operation of the coating liquid by the coating liquid suction device when the tip opening of the nozzle of the coating liquid discharge device reaches the final coating region of the coated member;
A coating apparatus comprising: While moving the coating liquid discharge device in the horizontal direction relative to the member to be coated placed on the support base, the coating liquid supply device is driven to supply the coating liquid to the coating liquid discharge device, A coating apparatus that applies a coating liquid to the coated member through a nozzle of a coating liquid discharge apparatus,
A branch pipe communicating in the middle of the pipe from the coating liquid discharge device to the nozzle;
Opening and closing means that allows the branch pipe to be opened to the outside air;
A control device for opening the branch pipe to the open air by the opening and closing means when the tip opening of the nozzle of the coating liquid discharge device reaches the final coating region of the coated member;
A coating apparatus comprising:   The coating apparatus according to claim 2, wherein an opening position of the branch pipe to the atmosphere is below a tip opening of a nozzle of the coating liquid discharge apparatus.   The coating apparatus according to claim 2, wherein the opening position of the branch pipe to the atmosphere is adjustable in the vertical direction. While moving the coating liquid discharge device in the horizontal direction relative to the member to be coated placed on the support base, the coating liquid supply device is driven to supply the coating liquid to the coating liquid discharge device, A coating method in which a coating liquid is applied to the coated member via a nozzle of a coating liquid discharge device,
The nozzle opening of the coating liquid discharge device reaches the final application region of the member to be coated, so that the nozzle passes through a branch pipe that communicates with the pipe extending from the coating liquid discharge device to the nozzle. A coating method characterized by starting a suction operation of the coating liquid inside. While moving the coating liquid discharge device in the horizontal direction relative to the member to be coated placed on the support base, the coating liquid supply device is driven to supply the coating liquid to the coating liquid discharge device, A coating method in which a coating liquid is applied to the coated member via a nozzle of a coating liquid discharge device,
When the tip opening of the nozzle of the coating liquid discharge device reaches the final coating region of the member to be coated, the branch pipe communicating with the pipe extending from the coating liquid discharge device to the nozzle is opened to the atmosphere. A coating method characterized by the above.

Images