JP5246122B2 - Coating liquid coating method, plasma display member manufacturing method, and coating liquid coating apparatus - Google Patents

Description

The present invention provides a coating liquid that efficiently cleans the periphery of a coating liquid discharge port of a coating head such as a die or a nozzle that discharges the coating liquid after the coating liquid is applied in a manufacturing process of a color filter, a plasma display, a printed circuit board, and the like. And a plasma display member, for example, a method for producing a light emitting substrate for plasma display, and a coating liquid coating apparatus.

  2. Description of the Related Art Conventionally, a coating liquid coating apparatus using a coating head such as a die or a nozzle is known as a coating liquid coating apparatus on a substrate. In the coating method of the coating liquid using the conventional coating apparatus, there is a problem that the coating head is soiled by the residual coating liquid after coating. This problem is particularly noticeable when a high-viscosity paste is used as the coating liquid. FIG. 2 is a schematic diagram showing a coating liquid coating method using a nozzle head which is an example of a coating head in a coating apparatus using a paste as a coating liquid. In FIG. 2, the paste 203 is supplied from the paste supply port 206 into the housing 207 of the nozzle head 200, and a plurality of discharge ports 202 are formed in a straight line on the lower surface of the nozzle head 200. . Here, a gas pressure such as compressed air is supplied from the gas pressure supply port 205, and the paste can be discharged and applied onto the substrate 1 placed so as to face the discharge port 202. In FIG. 2, stripe-shaped partition walls parallel to the coating direction are provided on the surface of the substrate 1, and high-precision coating is performed by applying paste between the partition walls. Such coating is used when a phosphor paste containing a large amount of phosphor powder is applied to a plasma display member, particularly a light emitting substrate for plasma display.

  However, in the coating liquid coating apparatus using the nozzle head 200, residual paste tends to adhere to the periphery of the discharge port 202 due to the discharge and stop of the paste from the discharge port 202. When the paste is discharged onto the substrate 1 placed so as to face the discharge port 202 in a state where the residual paste is attached to the peripheral portion of the discharge port 202 in this way, the paste discharge flow from the discharge port 202 becomes vertical. Therefore, it becomes difficult to apply the paste with high accuracy, that is, apply the paste on the substrate 1 in a straight line with a uniform thickness. Furthermore, since the amount of paste that adheres to the discharge port 202 as a residual paste is not constant and is not uniform over the longitudinal direction of the nozzle head 200, when the residual paste adheres to the substrate 1, a uniform thickness is applied over the entire region. It becomes impossible to do. In particular, when a high-viscosity paste having a viscosity exceeding 5000 mPa · s is used, the occurrence of the above problems becomes remarkable. In order to solve this problem, it is essential to reliably remove and clean the residual paste adhering to the discharge port 202 of the nozzle head 200 and its periphery before discharging the paste.

  As a conventional technique for cleaning the periphery of the discharge port of the coating head, the wiping member wetted with a solvent is pressed against the periphery of the paste discharge port with an elastic roll such as rubber, and then the coating head and the wiping member are relatively There is known a method of sliding and wiping off a residual paste adhering (for example, Patent Document 1). As shown in FIG. 3, the wiping member 104 made of a woven or knitted fabric is pressed against the discharge port 202 and the periphery of the discharge port by the pressing member 102 and is slid in a certain sliding direction 110 while being discharged by friction. This is a method of wiping off the residual paste 203a adhering to the outlet 202 and the periphery of the discharge port.

JP 2002-126599 A JP 2002-042651 A

  However, in this method, when the residual paste adhered in a large amount in the longitudinal direction of the coating head is wiped off by the wiping member, hard inorganic powder such as phosphor powder contained in the paste is removed around the discharge port of the coating head. There is a problem that the scratch 112 shown in FIG. 4 is generated on the surface of the coating head by sliding in a state where it is in contact with the portion. When such a flaw occurs in the coating head, the behavior of the paste discharge flow at the start of coating tends to become unstable, and it becomes difficult to apply a uniform thickness on the substrate, resulting in a significant loss of coating quality. For this reason, when a scratch occurs on the coating head, the coating head must be replaced with a scratch-free coating head. However, in order to replace the coating head, it is necessary to stop the coating device, which reduces productivity. . In addition, since such a coating head is processed with high accuracy and is very expensive, replacement of such a coating head due to generation of scratches reduces the manufacturing cost of a product manufactured by coating, for example, a plasma display panel. It will increase significantly.

  Therefore, the problem of the present invention is to pay attention to the above-mentioned problems and to reduce the residual coating liquid at the discharge port of the coating head and the peripheral portion of the discharge port, thereby enabling efficient removal while preventing the occurrence of scratches. Another object of the present invention is to provide a coating liquid coating method, a plasma display member manufacturing method, and a coating liquid coating apparatus.

  In order to solve the above-mentioned problems, the invention of claim 1 is characterized in that a coating liquid is ejected from the ejection port and applied onto the substrate while the coating head having the ejection port is moved relative to the substrate. When the discharge of the coating liquid from the discharge port is stopped and the discharge of the coating liquid is stopped, or after the discharge of the coating liquid is stopped, the relative movement of the coating head and the substrate is further stopped, and then the relative movement is stopped. A coating liquid coating method for separating a head from the substrate, wherein the substrate is charged at least before the coating head is separated from the substrate, and a potential difference between the substrate and the coating head at a coating liquid coating end position is obtained. It separates in the state of 200V or more, It is characterized by the above-mentioned.

  According to a second aspect of the present invention, the relative movement of the coating head and the substrate is relatively accelerated from the relatively stopped state to the constant relative movement speed V, and then the relative movement is performed at the relative movement speed V. It is divided into a constant speed period and then a deceleration period in which the relative movement speed V decelerates to a relatively stopped state, and discharge of the coating liquid from the discharge port is started in the acceleration period or constant speed period. Then, charging to the substrate is started in a constant speed period, discharge of the coating liquid from the discharge port is stopped in a deceleration period, and after the deceleration period, the coating head is separated from the substrate. It is characterized in that the charging to is stopped.

  According to a third aspect of the present invention, when the time from the start of charging to the substrate until the stable charging is obtained on the substrate is T1 (seconds), T1 (seconds) from the start of the deceleration period. ) The charging of the substrate is started before the above.

  According to a fourth aspect of the present invention, the coating head is ungrounded during the deceleration period and after the coating head and the substrate are relatively stopped until the coating head is separated from the substrate. And

  The invention of claim 5 is characterized in that at least the entire coated surface of the substrate is neutralized before the substrate is charged.

  The invention of claim 6 is characterized in that a charging means for charging the substrate is moved integrally with the coating head.

  According to a seventh aspect of the present invention, the discharge port of the coating head is composed of a plurality of discharge holes formed in a row at a predetermined pitch, and coating is performed over the entire width of the substrate by the single relative movement. It is characterized by.

  In the invention according to claim 8, the substrate includes a plurality of stripe-shaped partition walls parallel to the coating direction, a plurality of stripe-shaped main partition walls parallel to the coating direction, and a plurality of auxiliary partition walls substantially orthogonal to the main partition wall. A paste having a grid-like partition wall and containing a phosphor of any one color of red, green, or blue from a discharge port of a coating head in a recess formed between the partition walls using the coating liquid coating method according to claim 7 Is discharged as a coating liquid.

  Further, the invention of claim 9 includes a coating head for discharging a coating liquid, a mounting table for mounting a substrate to which a coating liquid discharged from the coating head is applied, and the coating head and the mounting table. A coating liquid coating apparatus comprising: a moving unit that relatively moves in a direction parallel to the surface of the mounting table; and a separating unit that separates the coating head from the mounting table, and a charging unit that charges the substrate. It is characterized by comprising a charge control means for controlling the charging timing to the substrate by the charging means, and a ground switching means for switching the coating head between a ground state and a non-ground state.

  In the invention according to any one of claims 1 to 9, by charging the substrate until the coating head is separated from the substrate after coating, the potential difference between the substrate and the coating head at the coating end position is separated in a state of 200 V or more, By drawing the coating liquid onto the substrate and sufficiently reducing the diameter of the discharge flow, the coating liquid is cut off at a position closer to the application head discharge opening. The liquid will only adhere to the residue.

  As a similar conventional technique, in Patent Document 2 described above, the electrostatic generator is moved integrally with the substrate, and is moved relative to each of the plurality of nozzles, and is opposite to the electrostatic pole on which the phosphor liquid is tinged. A method is described in which a fluorescent paste is smoothly injected into a concave portion of a substrate by applying a static electricity to the substrate and attracting the substrate by attracting and injecting the phosphor liquid into the concave portion of the substrate. However, in the phosphor film forming method of Patent Document 2, it is described that the substrate is charged during the coating operation, but a potential difference is applied between the substrate and the coating head even after the discharge of the coating liquid is stopped. Is not described, and the residual coating liquid adhering to the discharge port of the coating head and the periphery of the discharge port cannot be reduced.

  According to the second aspect of the present invention, when the coating head is separated from the substrate by stopping the charging of the substrate after separating the coating head from the substrate, it is ensured that the potential difference between the substrate and the coating head is 200 V or more. Can be retained.

  In the invention of claim 3, stable charging can be obtained at the coating end position on the substrate by starting charging the substrate at least T1 (seconds) before the start of the deceleration period.

  Further, in the invention of claim 4, it is possible to prevent the charge on the substrate from being attenuated by making the coating head ungrounded during the deceleration period and until the coating head is separated from the substrate. The potential difference is stable.

  Further, in the invention of claim 5, charging is obtained on the substrate with good reproducibility by removing the charge before charging the substrate.

  In the invention of claim 6, the vicinity of the coating end position can be charged by moving the charging means integrally with the coating head.

  Further, in the invention of claim 7, the coating method according to any one of claims 1 to 6 is provided, and the entire width of the substrate is applied by one discharge by using an application head composed of a plurality of discharge ports. Therefore, productivity can be improved.

  Moreover, in invention of Claim 8, a plasma display member is manufactured using the coating method of Claim 7.

1 is a schematic side view of a coating liquid coating apparatus according to an embodiment of the present invention. It is the schematic diagram which showed the coating method of the coating liquid using an example of a coating head. It is the schematic diagram which showed the cleaning method of the application head. It is the schematic diagram which showed the state of the abrasion of a discharge port peripheral part. It is the schematic diagram which showed the adhesion state of the residual coating liquid of a discharge port and a discharge port peripheral part. It is the schematic diagram which showed the state which spaced apart the coating head from the board | substrate. It is the camera image which caught the state which separated the coating head from the board | substrate with the camera. It is a time chart of the application | coating operation | movement in one embodiment of this invention. It is a schematic diagram explaining the coating method of the coating liquid by this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Hereinafter, a description will be given using a nozzle head which is an example of a phosphor coating nozzle for manufacturing a plasma display as a coating head and using a phosphor paste as a coating liquid. The present invention is not limited to this.

The configuration of the coating liquid coating apparatus A will be described with reference to FIG. First, a mounting table 10 on which a substrate 1 is mounted is guided freely in the X-axis direction by an X-axis moving rail 11 on a machine base 12, and is also passed through a ball screw (not shown) by an X-axis motor (not shown). Driven. Although not shown, the mounting table 10 has a mechanism for sucking and fixing the substrate 1 by vacuum suction.
A gate-shaped support machine base 13 is installed in the center of the machine base 12 in the width direction (direction perpendicular to the paper surface) of the substrate 1 on the mounting table 10. The support machine table 13 has a Z-axis moving rail 15 installed in a direction perpendicular to the substrate mounting surface of the mounting table 10, and is insulated from a holder 16 that freely moves up and down along the Z-axis moving rail 15. A nozzle head 200 is attached via the member 17. The longitudinal direction of the nozzle head 200 is arranged to coincide with the width direction of the substrate 1. The holder 16 and the nozzle head 200 are driven by a Z-axis motor 14 via a ball screw (not shown) and can freely reciprocate in the Z-axis direction (vertical direction). The insulating member 17 may be any member such as a sheet or a spacer. However, when the nozzle head 200 is attached to the holder 16 via the insulating member 17, the upper surface of the substrate 1 and the lower surface of the nozzle head 200 are not deformed. It is desirable that the distance can be obtained with high reproducibility when facing each other at a predetermined distance. As a material of the insulating member 17, for example, a known material such as rubber or resin can be used. Further, the resistance between the nozzle head 200 and the ground is preferably 1 × 10 ¹⁰ Ω or more, and more preferably 1 × 10 ¹² Ω or more. The nozzle head 200 is connected to the ground via the ground switching means 31. Thus, when the ground switching means 31 is operated, the nozzle head 200 can be switched between a ground state having the same potential as the ground and a non-ground state in which the ground is floated.

  Further, charging means 20a and 20b are provided via brackets on the downstream side (right side of the paper surface) and the upstream side (left side of the paper surface) so as to sandwich the nozzle head 200. The arrangement of the charging means 20a and 20b is preferable because the portion near the discharge port 202 of the nozzle head 200 can be efficiently charged near the position where the paste 203 is cut off when the nozzle head 200 is separated from the substrate 1. Further, by integrating the charging means 20a and 20b with the nozzle head 200, the position where the nozzle head 200 is separated from the substrate 1, that is, the vicinity of the position where the paste 203 is cut off can be effectively charged. Therefore, when the nozzle head 200 is separated from the substrate 1, it is preferable because the paste 203 is attracted to the substrate 1 and the diameter of the discharge flow becomes sufficiently thin. The charging units 20a and 20b are integrated with the nozzle head 200. However, the present invention is not limited to this. When the nozzle head 200 is separated from the substrate 1, the potential difference between the substrate 1 and the nozzle head 200 is a predetermined value or more. The charging means 20a and 20b may be provided at any position as long as they are stable.

When the charging means is moved integrally with the substrate and relative to the nozzle, it tends to be difficult to uniformly apply the charge to the coating surface. For this reason, when the charging means is disposed in the vicinity of the application start position when applying in one direction, the substrate is sufficiently charged and the discharge flow is stable, but the discharge flow is stabilized near the application end position. Insufficient charging is likely to cause a problem that the discharge flow becomes unstable. In this state, even if the nozzle is separated from the substrate, the discharge flow is hardly attracted to the substrate, and it is difficult to make the discharge flow sufficiently thin.
As the charging means 20a and 20b, it is sufficient to charge static electricity having only one of positive and negative polarities. Therefore, a corona discharge type static eliminator (for example, SJ-H132 manufactured by Keyence Corporation) can be used. Having an effective length that is equal to or longer than the longitudinal direction of the head 200 is advantageous because the charging effect can be imparted to all the discharge ports 202 and the peripheral portions of the discharge ports. In addition, when applying the charge, if the charge applying position of the charging unit 20b does not deviate from the substrate 1, using the charging unit 20a can increase the amount of charge. The charging means 20b can also be used when charging the vicinity of the coating start position of the substrate 1. The desired charge amount can be appropriately adjusted according to the paste type and substrate type.

  Further, when the distance between the substrate 1 and the ejection port 202 of the nozzle head 200 is opposed to a predetermined value, the distance between the substrate 1 and the charging means 20a and 20b is set to a predetermined value (for example, 50 mm). It has become. The charging units 20 a and 20 b are connected to the charging control unit 30. The charging control means 30 controls the start / stop timing of charging the substrate 1.

  The neutralizing means 21 a and 21 b for neutralizing the substrate 1 are provided on the downstream side (right side of the paper surface) and the upstream side (left side of the paper surface) of the nozzle head 200. By passing the substrate 1 below the neutralizing means 21b, at least the entire coated surface of the substrate 1 is neutralized. When the substrate 1 is placed on the mounting table 10, the substrate 1 is often charged non-uniformly to either the positive electrode or the negative electrode, and neutralizing the substrate 1 by neutralizing the electrode stabilizes the coating. In addition, in the case where the substrate 1 is charged, it is preferable because a desired charge amount can be easily obtained on the surface of the substrate 1 with good reproducibility. In addition, it is preferable that, after the coating, the substrate 1 passes under the static elimination means 21a, so that it is possible to prevent the charged substrate 1 from being carried out to the next process. The static elimination means 21a is not essential, and may be determined in view of the amount of remaining charge of the substrate 1 after coating and the equipment of the next process. As the static elimination means 21a and 21b, a corona discharge type static eliminator (for example, SJ-R132 manufactured by Keyence Corporation) can be used. The effective length is preferably equal to or greater than the width direction of the substrate 1 (direction perpendicular to the paper surface). The distance between the substrate 1 and the static elimination means 21a and 21b is set to a predetermined value (for example, 500 mm).

  A wiping device 100 configured as a cleaning device for a nozzle head 200 described later is provided on the downstream side of the machine base 12 in FIG. The wiping device 100 is moved along the X-axis moving rail 11 from a position J shown in FIG. 1 (hereinafter referred to as a standby position J) to a nozzle head wiping position H that is located immediately below the nozzle head 200 (the wiping device 100 is indicated by a broken line). Can be freely reciprocated independently of the mounting table 10.

  Next, after the preparatory work described later, when the coating work is started, the mounting table 10 starts moving toward the nozzle head 200 and is provided on the upstream side (left side of the paper surface) of the nozzle head 200. The mounting table 10 passes under the static eliminating means 21b. When the mounting table 10 reaches the image processing position of the substrate 1 by an alignment apparatus (not shown), the movement of the mounting table 10 is stopped and image processing of the substrate 1 is performed.

  Thereafter, a coating operation as shown in FIG. 8 is started. First, the mounting table 10 is in a speed-up period in which the movement is stopped to a constant speed V (coating speed), then in a constant speed period in which the stage 10 is moved at the moving speed V (coating speed), and then in the moving speed V ( It moves in the deceleration period in which it decelerates from the coating speed to the stopped state.

  In the speed-up period, as shown in FIG. 9 and FIG. 2, slightly before the application start position of the substrate 1 reaches just below the discharge port 202 of the nozzle head 200 (for example, 10 mm) or at the same time, the lower surface of the nozzle head 200 and the substrate The Z-axis motor 14 is operated so that the distance to the top of one partition wall or the bottom between the partition walls becomes a predetermined value, and the nozzle head 200 is lowered. When the application start position of the substrate 1 reaches just below the discharge port 202 of the nozzle head 200, compressed air is supplied to the gas pressure supply port 205 of the nozzle head 200, and gas is pressurized to discharge the nozzle head 200. The paste 203 is discharged from the outlet 202, and the paste 203 is applied between the partition walls of the substrate 1. Then, the mounting table 10 shifts to the constant speed period. Although application to the substrate 1 is started in the acceleration period of the mounting table 10, the present invention is not limited to this. For example, in a plasma display, if the non-display area can secure a sufficient width, the mounting table Application may be started in a constant speed period when 10 reaches the moving speed V (application speed).

  In the constant speed period, the charging control unit 30 is operated to start charging the substrate 1 using the charging unit 20a and / or 20b. When the time from the start of charging to the substrate 1 until the stable charging on the substrate 1 is obtained is T1 (seconds), the charging can be started at least T1 (seconds) before the start of the deceleration period. It is important to obtain a stable charge in the deceleration period. The time T1 (seconds) from the start of charging to the time when stable charging is obtained on the substrate is preliminarily applied to the substrate by using this apparatus, and a potential sensor for monitoring the amount of charging is set as a nozzle. It is preferable to provide the value near the head 200 to obtain the value. Or you may use the reference value of a corona discharge type static eliminator (for example, Keyence Corporation) maker.

  The amount of charge applied to the substrate is preferably 200 V or more, more preferably 400 V or more, and even more preferably 600 V or more with respect to the coating head. Furthermore, the charge amount is preferably 2000 V or less, and the time until the charge amount is reached is preferably 2 seconds or less, more preferably 1 second or less. If the potential difference between the substrate and the nozzle head 200 exceeds 2000 V, discharge is likely to occur between the substrate and the nozzle head 200, which is not preferable.

  The smaller the fluctuation of the moving speed V (coating speed) in the constant speed period, the better. For example, when the moving speed V (coating speed) is 100 mm / second, the speed fluctuation is preferably 0.5% or less, more preferably 0.3% or less. If the speed fluctuation is large, problems such as uneven coating and adhesion of the paste 203 to the top of the partition wall are not preferable. Further, the acceleration and deceleration of the mounting table 10 need not be performed at a constant acceleration, and may be performed in multiple stages. Note that if the start of charging is made more than T1 (seconds) before the start of the deceleration period, excessive charge will be applied to the substrate 1, and it will take time to remove static electricity when the substrate 1 is carried out to the next process. Is not preferable because it extends.

  Furthermore, some pastes carry electricity. Therefore, when the charging control unit 30 is operated to start charging the substrate 1, or before starting charging (for example, 1 second), the ground switching unit 31 is used to place the nozzle head 200 in the ground state having the same potential as the ground. Switch to the ungrounded state with the ground floating. By this operation, it is possible to prevent static electricity applied on the substrate 1 from being transferred to the ground 203 via the nozzle head 200 through the paste 203 being applied, so that even when the nozzle head 200 is separated from the substrate 1, 1 and the nozzle head 200 are stabilized when the potential difference is 200 V or more.

  When the application end position of the substrate 1 comes under the discharge port 202 of the nozzle head 200 in the deceleration period, the supply of compressed air to the nozzle head 200 is stopped, and the time until the end of the deceleration period or the stop is stabilized After a lapse of time (for example, 1 second), the Z-axis motor 14 is operated to separate the nozzle head 200 from the substrate 1 and completely cut off the paste 203. Even after the nozzle head 200 is separated from the substrate 1, the charging is continued (for example, 1 second), and then the charging control unit 30 is operated to stop the charging to the substrate 1. Further, simultaneously with the stop of charging of the substrate 1 or after a predetermined time (for example, 1 second), the ground switching means 31 is operated to ground the nozzle head 200 from the non-ground state in which the ground is floated to the same potential as the ground. Switch to state. By this operation, the static electricity charged in the nozzle head 200 including the paste 203 can be released to the ground, so that the influence of charging on the next application can be reduced.

  By continuing charging and non-grounding of the nozzle head 200 until the nozzle head 200 is separated from the substrate 1, a stable potential difference is obtained between the substrate 1 and the nozzle head 200 until the separation is completed.

  As described above, at least during the deceleration period and until the nozzle head 200 is separated from the substrate 1, the nozzle head 200 is in a non-grounded state in which the ground is floated. However, the present invention is not limited to this. As long as the potential difference between the substrate 1 and the nozzle head 200 can be stably secured at 200 V or more in the vicinity of the position where the coating is finished and the position where the paste 203 is cut off, the nozzle head 200 does not necessarily have to be ungrounded.

When the substrate 1 is charged, the leakage resistance of the mounting table 10 is preferably 1 × 10 ⁶ Ω or more, more preferably 1 × 10 ¹⁰ Ω or more and 1 × 10 ¹⁴ Ω or less. If the leakage resistance is low, the decay rate of static electricity charged on the substrate 1 is high, and it is difficult to secure a potential difference of 200 V or more in the vicinity of the position where the nozzle head 200 is separated from the substrate 1. On the other hand, if the leakage resistance is 1 × 10 ¹⁴ Ω or more, the static electricity charged on the mounting table 10 is difficult to attenuate, and the static electricity remains until the next step, which is not preferable. The leakage resistance is a resistance between the surface of the mounting table 10 and the ground.

  In FIG. 1, when the coating operation is completed, the mounting table 10 further moves to the downstream side (the right side of the paper surface) and passes under the static elimination means 21 a to neutralize the charge on the substrate 1. Then, the mounting table 10 moves to a substrate discharge position (not shown) and stops. Thereafter, the vacuum suction of the mounting table 10 is released, and the substrate 1 is raised by lift pins (not shown). And the board | substrate 1 is carried out to the following process by the transfer machine which is not shown in figure. After the lift pins are lowered, the mounting table 10 returns to the preparation position (the position of the mounting table 10 in FIG. 1) to complete the coating operation.

  When the above coating operation is repeated, unless the discharge port 202 and the periphery of the discharge port of the nozzle head 200 are cleaned before coating, variations in the discharge amount occur and the behavior of the discharge flow is disturbed, resulting in unstable coating. Therefore, cleaning of the nozzle head 200 is essential. However, if the potential difference between the substrate 1 and the nozzle head 200 in the vicinity of the coating end position and the position where the paste 203 is cut off is 200 V or more and the optimum conditions for separating the nozzle head 200 from the substrate 1 can be found, the discharge port 202 of the nozzle head 200 is detected. In addition, since the residual paste hardly adheres to the periphery of the discharge port, even when the coating operation is repeated, cleaning of the nozzle head 200 before the coating is not essential and the cleaning time can be shortened, which is preferable.

  Further, the static elimination means 21a and 21b may be in an always operating state to neutralize the substrate 1 passing under the static elimination means, but when the substrate 1 is charged using the charging means 20a and / or 20b. The arrangement of the static elimination means 21a and 21b must be taken into consideration so that the charging of the substrate 1 is not attenuated due to the influence of the static elimination means, or discharge is not generated between the static electricity and the charging means.

  Further, a mechanism for monitoring the amount of charge on the substrate is provided, and if the timing for starting charging or the time until charging ends and the grounding state of the nozzle head 200 are manipulated so that the monitored value becomes substantially constant, Effective charging is obtained.

  As the movement drive mechanism for each of the X-axis, Z-axis, and other axes in FIG. 1, in addition to a system that converts a rotary motion into a linear motion using a servo motor and a ball screw, a system that performs a linear motion directly such as a linear motor or an air cylinder. However, any method may be used as long as the positioning accuracy and speed accuracy required for the coating liquid coating apparatus can be achieved. Further, as a guide for guiding linear motion, an air bearing may be used in addition to a normal linear guide. Each axis is provided with a position sensor (not shown) for detecting the movement position. Instead of using the position sensor, the position of each shaft may be detected by using a motor in which an encoder is incorporated.

  Next, the configuration of the nozzle head 200 shown in FIG. 2 will be described. The nozzle head 200 includes a housing 207 and a top plate 204. A reservoir portion of the paste 203 and an air chamber 201 are formed inside the housing 207, and a plurality of paste discharge ports 202 are formed in a straight line on the bottom surface of the housing 207. The upper surface plate 204 is provided with a gas pressure supply port 205 and a paste supply port 206. The paste 203 is supplied from the paste supply port 206, stored in the air chamber 201, and then pressurized by a gas pressure such as compressed air from the gas pressure supply port 205, and placed so as to face the discharge port 202. The paste 203 is applied between the partition walls of the substrate 1 by discharging. Here, as a paste discharging method, in addition to a method of pressurizing with a gas pressure, a method of supplying a fixed amount by a constant capacity pump such as a syringe pump or a gear pump may be used, and an optimum method is selected according to paste characteristics and application conditions. It is desirable.

  The discharge port 202 may be singular or plural, and may have any shape such as a slit, a circle, an ellipse, or a polygon, but a phosphor layer necessary for one screen in a plasma display The number of circular discharge ports 202 (for example, about 50 to 200 μm in diameter) equal to or greater than the number of pixels in the scanning direction (for example, about 1000 to 4000) can be applied at least once for each color. The nozzle head 200 is preferably provided by being drilled in a straight line in the longitudinal direction.

  As the substrate 1, a type having a plurality of stripe-shaped partition walls parallel to the coating direction, or a cross-beam shape including a plurality of stripe-shaped main partition walls parallel to the coating direction and a plurality of auxiliary partition walls perpendicular to the main partition wall is formed. The type etc. currently used can be used. The board | substrate 1 is not limited to this, The board | substrate with the partition of a complicated shape may be sufficient. When applying to a substrate having a partition wall using the nozzle head 200 described above, it is necessary to apply with very high accuracy, so that a problem easily occurs when residual paste is adhered, and the present invention is particularly preferable. Can be used.

  The paste applied to the substrate 1 may be a paste containing phosphors of any one of red, green, and blue having a high viscosity of 1000 to 100,000 mPa · s.

  Next, with reference to FIG. 3, the wiping apparatus 100 which is the cleaning apparatus of the nozzle head 200 is demonstrated. An unwinding member roll 101 for unwinding the wiping member 104, a pressing member 102 around which the unwound wiping member 104 is wound, and a winding member roll 103 for winding the wiping member 104 that has passed through the pressing member 102 are provided. Here, as shown in FIG. 1, the pressing member 102 can press the wiping member 104 against the nozzle head 200 at the nozzle head wiping position H. The pressing member 102 is formed on a roll by fixing an elastic body to a fixed core shaft. The elastic body is suitable to have an appropriate softness and flexibility that conforms to the shape of the pressed counterpart, and it is preferable to use foaming sponge, synthetic rubber or the like. Specifically, silicon sponge, polyethylene sponge, fluorine sponge, silicon rubber and the like are preferable. In addition, about the shape of the pressing member 102, the rectangular parallelepiped whose contact surface becomes a plane other than a cylindrical shape may be sufficient.

  The unwinding member roll 101 and the winding member roll 103 are driven by an unwinding motor (not shown) and a winding motor (not shown). It is preferable that tension is always applied to the wiping member 104 so that the wiping member 104 does not wrinkle on the pressing member 102. A cloth material is used for the wiping member 104. Although there are many types of cloth materials, those having a high effect of removing dirt by wiping, and having no fluff and the like and not generating dust are preferable. As a specific example, a nonwoven fabric using ultrafine fibers is preferable.

  Further, in order to surely wipe off the paste and solvent adhering to the nozzle head 200, when the wiping member 104 is pressed against the nozzle head 200 by the pressing member 102, the wiping member 104 is sufficiently adhered to the nozzle head 200. It is necessary to be. Therefore, the pressing member 102 is required to have an appropriate flexibility. Specifically, when the elastic bodies of the wiping member 104 and the pressing member 102 are overlapped and collectively measured with a rubber hardness meter (conforming to JIS K6351), the rubber hardness is set to 15 to 60 degrees. It is preferable to realize.

  In addition, when a solvent is sprayed on the wiping member 104 on the pressing member 102 for the purpose of improving the wiping effect, the solvent to be sprayed is a highly volatile solvent having a boiling point of 80 ° C. or less and substantially equal to the longitudinal direction of the nozzle head 200. It is preferable to apply this length. Specific examples include acetone, ethanol, methanol and the like. Then, the nozzle head 200 is cleaned by sliding the wiping device 100 in the direction of the arrow 110.

  Here, it is preferable that the pressing amount of the nozzle head 200 to the pressing member 102 is 0.1 to 1 mm. If the amount of pressing is insufficient, the nozzle head 200 and the wiping member 104 do not contact evenly, and the residual paste 203a and the solvent around the discharge port 202 and the discharge port cannot be wiped off reliably. Further, if the pushing amount is excessive, a large load is applied to the nozzle head 200 and the pressing member 102 during the wiping operation, and the pressing member 102 is damaged. Further, the wiping device 100 is moved in the direction of the arrow 110 at a speed of 10 to 40 mm / second.

  Preparatory work is performed before the application work is started. First, as a preparatory work, the nozzle head 200 is filled with paste. The paste is supplied from the paste supply source through the paste supply port 206 using gas pressure, and is filled in the nozzle head 200. Then, when a predetermined amount of paste is filled and the air removal from the nozzle head 200 is completed, the supply of the paste is stopped. Thereafter, when the origin of each operating part in the coating device is returned, the mounting table 10 and the nozzle head 200 are respectively prepared in the X-axis and Z-axis preparation positions (the mounting table is the position of the mounting table 10 in FIG. 1, and the nozzle head is not shown). ) The wiping device 100 also moves to the standby position J. Then, lift pins (not shown) rise on the surface of the mounting table 10, and the substrate 1 is placed on the top of the lift pins from a transfer machine (not shown).

Next, the lift pins are lowered to place the substrate 1 on the upper surface of the mounting table 10, the substrate 1 is positioned by a substrate positioning device (not shown), and the substrate 1 is suction-fixed.
Next, the residual paste 203a adhering to the discharge port 202 and the periphery of the discharge port of the nozzle head 200 is removed and cleaned using the wiping device 100. First, the wiping device 100 located at the standby position J in FIG. 1 sends the wiping member 104 from the unwinding member roll 101 to the winding member roll 103, and removes the wiping member 104 in contact with the nozzle head 200 from an unused clean part. Update to Then, the nozzle head wiping position H (a position indicated by a broken line of the wiping device 100) located immediately below the nozzle head 200 from the standby position J in FIG. . The nozzle head wiping position H is a position where the wiping member 104 contacts the nozzle head 200. Then, the wiping device 100 is moved along the X-axis moving rail 11 to the downstream side (the right side of the drawing). When the pressing member 102 passes under the nozzle head 200, that is, when the nozzle head wiping position H is reached, the wiping member 104 is pressed against the discharge port 202 and the discharge port peripheral portion of the nozzle head 200 and slides. Therefore, the residual paste 203a adhering to the discharge port 202 and the periphery of the discharge port can be removed and cleaned. Thereafter, the wiping device 100 moves to the standby position J in FIG.

When the residual paste 203a is adhering in a large amount and non-uniformly to the discharge port 202 and the periphery of the discharge port of the nozzle head 200, it is difficult to reliably remove and clean the residual paste 203a with a single slide. There is a case. At this time, it is necessary to increase the number of times of sliding or to increase the amount of pressing of the nozzle head 200 into the pressing member 102. As a result, the generation of scratches becomes prominent at the discharge port 202 and the periphery of the discharge port of the nozzle head 200. Further, when the number of sliding times increases, efficient cleaning cannot be performed, resulting in a problem that productivity is lowered. Therefore, the residual paste adhering to the discharge port 202 and the periphery of the discharge port of the nozzle head 200 must always be small and uniform.
Next, the mounting table 10 is moved toward the nozzle head 200 on the downstream side (the right side of the paper), and the center position of the groove between the partition walls of the substrate 1 and the representative discharge port of the nozzle head 200 are aligned by an alignment device (not shown). Alignment control to match is performed. This alignment control may be performed once in the preparatory work, but by performing it every predetermined number of times, the center of the groove between the partition walls of the substrate and the representative discharge port of the nozzle head 200 can be matched each time. This is preferable because it is possible to prevent the substrate and the nozzle head 200 from being displaced in the direction orthogonal to the application direction, and to realize application with high accuracy. Moreover, since application can be performed with high accuracy, excess paste does not adhere to the lower surface of the nozzle 200 during application. Thereafter, the mounting table 10 moves to a preparation position (position of the mounting table 10 in FIG. 1) provided on the upstream side (left side of the paper surface). In this way, the preparation work is completed.

  In the above description, the mounting of the substrate 1 on the mounting table 10 and the wiping operation of the nozzle head 200 are separated. However, the present invention is not limited to this, and the nozzle head 200 is mounted in parallel with the mounting of the substrate 1. You may wipe off. It is preferable because the tact can be shortened by working in parallel.

  As is clear from the above description, the potential difference between the substrate and the nozzle head in the vicinity of the paste application end position and the position where the paste is cut off by charging the substrate before the nozzle head is separated from the substrate and continuing the charging after the separation. Since the nozzle head is separated from the substrate while reliably holding 200 V or higher, the paste can be cut off at a location closer to the nozzle head outlet as shown in FIG. A small amount of uniform paste remains only on the discharge port and the periphery of the discharge port. Therefore, even when the attached residual paste is wiped off using the wiping member, it is possible to suppress the occurrence of scratches, and the residual paste can be removed in a short time, thereby improving productivity.

  On the other hand, when the nozzle head is separated from the substrate, the potential difference between the substrate and the nozzle head in the vicinity of the paste application end position and the position where the paste is cut off is not sufficiently secured. As shown in (a), a large amount of residual paste adheres.

Comparative Example 1
In the coating apparatus shown in FIG. 1, first, as a preparatory work, a nozzle head, which is an example of a coating head, is filled with a paste (viscosity of about 30 Pa · s) containing a red (R) phosphor, Cleaning was performed with a wiping device. A solvent hexanol for wiping (boiling point 157.1 ° C., flash point 63 ° C.) was used, and a solvent coating amount of 0.5 cc was applied to a coating width of 10 mm and a coating length of about 970 mm. The nozzle head used was a nozzle head having 1280 nozzles with a diameter of 150 μm and a pitch of 750 μm. In parallel with the cleaning, a substrate having a substrate size of 990 × 600 mm on the mounting table, a substrate having a height of 100 μm and a top width of 70 μm formed on a substrate surface with 3841 pitches at a pitch of 250 μm (groove width of 180 μm) is transferred. The substrate was positioned by a substrate positioning device and then fixed by suction. After that, alignment control was performed by the alignment device so that the representative inter-partition groove center position coincided with the representative ejection port of the nozzle head. The neutralization means 21a and 21b were operated, the charging means 20a and 20b were stopped, and the mounting table passed under the neutralization means 21b, so that at least the entire coated surface of the substrate was neutralized. The static elimination means 21a and 21b were made into the normal operation state using a commercially available 1320 mm corona discharge type static eliminator (manufactured by Keyence Corporation, SJ-R132). Then, at the same time when the substrate application start position reached directly below the nozzle head discharge port, the distance between the nozzle head lower surface and the partition wall apex of the substrate was set to 100 μm, and application was started by applying a pressure of about 300 KPa to the nozzle head. The moving speed at the start of application of the mounting table was 20 mm / second, and when the moving speed moved 20 mm from the start of application, the moving speed V (coating speed) was increased to 80 mm / second to shift to the constant speed period. When the application end position of the substrate provided in the deceleration period reaches directly below the nozzle head discharge port, the discharge is stopped, and the movement of the mounting table is stopped almost simultaneously, and wait 0.5 seconds for the stop to stabilize. The nozzle head was separated from the substrate.

As a result, as shown in FIG. 5A, residual paste 203a could be confirmed at the discharge port of the nozzle head and the periphery of the discharge port. This residual paste 203a adhered in a large amount unevenly in the longitudinal direction of the nozzle head. Further, when the state in which the nozzle head was separated from the substrate was observed, as shown in FIG. 6A, the paste was cut off from the substrate below the discharge port of the nozzle head, and the paste became a residual paste around the discharge port. It was attached to. FIG. 7A shows the result of capturing the situation with a camera.
Example 1
The charging unit 20a was in an operating state. The time from the start of charging until the stable charging was obtained on the substrate was measured in advance, and it was about 1 second. The start and end timing of charging was input to the charging control means. First, the start of charging was 1.5 seconds before the start of the deceleration period, and the end of charging was 2 seconds after the nozzle head was separated from the substrate. Further, the timing for setting the nozzle head to ground / non-ground was input to the ground switching means. Switching from the grounded state to the non-grounded state was made 1 second before the start of charging, and switching from the non-grounded state to the grounded state was made 1 second after the end of charging. As the charging means 20a, a commercially available 1320 mm corona discharge static eliminator (manufactured by Keyence Corporation, SJ-H132) was used to charge the substrate to the negative electrode. In order to monitor the charge amount of the substrate, a potential sensor was installed in the vicinity of the nozzle head. In addition, the trek Japan company make (MODEL533C-S) was used for the electric potential sensor. Other than that, the same application as in Comparative Example 1 was performed.

As a result, as shown in FIG. 5 (b), the residual paste 203a adhered uniformly in a small amount in a concentric manner at the nozzle head discharge port. When the diameter of the residual paste 203a was measured with a CCD camera, it was about 210 μm. If this diameter exceeds about 470 μm, not only the residual paste can be removed in a short time, but also when the nozzle head discharge port and the periphery of the discharge port are cleaned using the above-described wiping device in this state for a long time, scratches are generated. It has been experimentally found that it becomes difficult to suppress this. A similar small amount and uniform residual paste 203a was also adhered in the longitudinal direction of the nozzle head. When each recorded waveform was confirmed, it was confirmed that each means was operating according to the set value. Further, the potential difference between the substrate and the nozzle head at the time of separation was about 900V. When the coated substrate was confirmed, the coating was not disturbed in the vicinity of the coating start position and the coating end position. Furthermore, when the state in which the nozzle head was separated from the substrate was observed, as shown in FIG. 6B, the paste was cut off from the substrate at a location closer to the discharge port of the nozzle head. Only a small amount of residual paste adhered. FIG. 7B shows the result of capturing the situation with a camera.
The coating was repeated 10 times, but the potential difference between the substrate and the nozzle head was around 900 V in all 10 times, and the residual paste around the nozzle head discharge port and the discharge port was small and uniform. Also, the coated substrate was not aligned in a uniform manner and was aligned in a horizontal line.
Example 2
Next, a potential sensor that monitors the charge amount of the substrate provided in the vicinity of the nozzle head so that the potential difference between the substrate and the coating head in the vicinity of the coating end position and in the vicinity of the position where the paste is cut off is 200 V with the charging unit 20a in the operating state. While confirming, the charging start position of the charging means 20a, the time to stop charging, and the mounting height of the charging means were operated. The ground switching means was not operated, and the nozzle head was kept in the ground state. Other than that, the same application as in Example 1 was performed.

As a result, when the end of application of the substrate was confirmed, it was perfectly aligned horizontally. When the concentric residual paste 203a at the nozzle head discharge port after application was confirmed by a CCD camera, the diameter was about 390 μm, which was larger than that in Example 1, but the adhesion amount was uniform. The coating was repeated 10 times. When the coating start position and the vicinity of the coating end position were confirmed on all the substrates, they were neatly aligned in a horizontal line. Moreover, the potential difference between the substrate and the nozzle head at the time of separation in the recording waveform showed 200 V or more for all 10 times.
Example 3
After the application of Example 1 was repeated and the application was continuously performed on 2,000 substrates, the occurrence of scratches on the nozzle head discharge port and the periphery of the discharge port was confirmed. The generation | occurrence | production of the very slight damage | wound was confirmed to the discharge port periphery part.
Comparative Example 2
After the application of Comparative Example 1 was repeated and the application was continuously performed on 2,000 substrates, the occurrence of scratches on the nozzle head discharge port and the periphery of the discharge port was confirmed. Many scratches could be confirmed around the discharge port.

  The present invention is suitable as a coating method and a coating apparatus for coating a high-viscosity coating liquid in the production of color filters, plasma displays, printed boards and the like.

DESCRIPTION OF SYMBOLS 1 Board | substrate 10 Mounting base 11 X-axis moving rail 12 Machine base 13 Supporting machine base 14 Z-axis motor 15 Z-axis moving rail 16 Holder 17 Insulating member 30 Charging control means 31 Ground switching means 20a, 20b Charging means 21a, 21b Static elimination means 100 Wiping device 101 Unwinding member roll 102 Pushing member 103 Winding member roll 104 Wiping member 110 Sliding direction 112 Scratch 200 Nozzle head 201 Air chamber 202 Discharge port 203 Paste 204 Upper surface plate 205 Gas pressure supply port 206 Paste supply port 207 Housing Body 203a Residual paste H Nozzle head wiping position J Standby position

Claims (9)

  A coating liquid having a discharge port is moved relative to the substrate while being moved relative to the substrate, a coating liquid is discharged from the discharge port and applied onto the substrate, and the discharge of the coating liquid from the discharge port is stopped. At the same time or after stopping the discharge of the coating liquid, the relative movement of the coating head and the substrate is stopped, and then the relative movement is stopped, and then the coating head is separated from the substrate. The coating liquid is charged at least before the coating head is separated from the substrate, and the coating liquid is separated in a state where the potential difference between the substrate and the coating head at the coating liquid coating end position is 200 V or more. Application method.   The relative movement between the coating head and the substrate is accelerated during a period from a relatively stopped state to a constant relative movement speed V, followed by a constant speed period during which relative movement is performed at the relative movement speed V, and then the relative movement. It is divided into a deceleration period in which the speed is gradually reduced from the speed V to a relatively stopped state, and the discharge of the coating liquid from the discharge port is started in the acceleration period or the constant speed period, and to the substrate in the constant speed period. Charging is stopped, discharging of the coating liquid from the discharge port is stopped during the deceleration period, and charging of the substrate is stopped after the coating head is separated from the substrate after the deceleration period. The coating method of the coating liquid according to claim 1.   When the time from the start of charging to the substrate until stable charging is obtained on the substrate is T1 (seconds), the charging of the substrate is performed at least T1 (seconds) before the start of the deceleration period. 3. The coating liquid coating method according to claim 2, wherein the coating liquid is applied.   The coating head is ungrounded during the deceleration period and after the coating head and the substrate are relatively stopped until the coating head is separated from the substrate. How to apply the coating liquid.   5. The coating liquid coating method according to claim 1, wherein at least the entire coated surface of the substrate is neutralized before the substrate is charged. 6.   The coating method of a coating liquid according to claim 1, wherein charging means for charging the substrate is moved integrally with the coating head.   The discharge port of the coating head is composed of a plurality of discharge holes formed in a row at a predetermined pitch, and coating is performed over the entire width of the substrate by the single relative movement. How to apply the coating liquid.   The substrate has a plurality of stripe-shaped partition walls parallel to the coating direction or a plurality of stripe-shaped main partition walls parallel to the coating direction and a plurality of auxiliary partition walls substantially perpendicular to the main partition wall; The paste containing the phosphor of any one color of red, green, or blue is discharged as a coating liquid from the discharge port of the coating head into the recess formed between the partition walls using the coating liquid coating method according to Item 7. A method for producing a plasma display member. A coating head for discharging a coating liquid, a mounting table for mounting a substrate to which a coating liquid discharged from the coating head is applied, and the coating head and the mounting table in a direction parallel to the mounting table surface. A coating liquid coating apparatus having a moving means for moving the coating head and a separating means for separating the coating head from the mounting table, a charging means for charging the substrate, and charging the substrate by the charging means A coating liquid coating apparatus, comprising: a charging control means for controlling the application timing of the coating liquid; and a ground switching means for switching the coating head between a grounded state and a non-grounded state.