JP2010279865A - Coating liquid applicator and method of adjusting discharge amount - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correctly measure the discharge amount of each nozzle of a coating head, even under the state that a plurality of piezoelectric elements of all the available nozzles or a plurality of nozzles are driven simultaneously. <P>SOLUTION: The coating liquid applicator 10 discharges a coating liquid, in the form of liquid droplets, to the surface of a substrate 1 from a plurality of nozzles arranged at a specified interval and thus, makes an application of the coating liquid. In addition, the coating liquid applicator 10 has a container 21 which makes storing per nozzle of the liquid droplets of the coating liquid discharged from each nozzle, and a weight measuring device which measures the weight of the coating liquid stored per nozzle in the container 21. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a coating liquid coating apparatus for a substrate.

  In a manufacturing process of a liquid crystal display device or the like, an ink jet type coating apparatus for forming a functional thin film on a substrate is used in a film forming process for forming a circuit pattern on a glass substrate.

  As described in Patent Document 1, this coating apparatus has a mounting table for transporting a substrate. Above the mounting table, a plurality of coating heads are in a direction substantially perpendicular to the transport direction of the substrate. Are arranged along. A coating liquid discharged from a plurality of nozzles provided in each coating head is applied to the upper surface of the substrate to be transported at a predetermined interval. Each coating head is provided with a piezoelectric element facing each nozzle through a flexible plate. When a voltage is applied to the piezoelectric element, the flexible plate is deformed, and the coating liquid is discharged from the corresponding nozzle. Even if the same voltage is applied to each piezoelectric element facing each nozzle, each coating head has different characteristics depending on the piping resistance from the supply source of the coating liquid, manufacturing accuracy, assembly accuracy, etc. A difference occurs in the discharge amount of the liquid. As a result, the thickness of the functional thin film formed on the substrate is not uniform.

  Therefore, in the coating apparatus described in Patent Document 1, droplets of the coating liquid discharged from a plurality of nozzles of the coating head are stored in a container, and the weight of the coating liquid stored in the container is measured with a scale, and the measurement is performed. Based on the result, the voltage applied to the piezoelectric element corresponding to each nozzle of each coating head is adjusted.

JP2007-136450

  The coating apparatus described in Patent Document 1 is configured to store coating liquid droplets discharged from a plurality of nozzles provided in one coating head in a single container, and to be applied from a plurality of nozzles. It only measures the total amount of liquid. Therefore, the discharge amount of the coating liquid for each nozzle cannot be measured, and it is difficult to control the discharge amount of each nozzle for each nozzle and adjust the discharge amount from each nozzle to be equal to each other.

  In addition, in the coating apparatus described in Patent Document 1, when measuring the discharge amount of the coating liquid discharged from the coating head for each nozzle, it is assumed that one container is used for one coating head. Only the piezoelectric element of one nozzle of all nozzles provided in one coating head is driven, the coating liquid discharged from the nozzle is accommodated in one container, and its weight is measured. However, in the inkjet type coating head, due to its structure, the discharge amount from one nozzle corresponds to the discharge amount when all the piezoelectric elements of the nozzles are driven at the same time, and when only the piezoelectric element of the one nozzle is driven. The discharge amount may not be the same. Therefore, in this case, the discharge amount for each nozzle of the coating head cannot be measured correctly in a state where the piezoelectric elements of all nozzles or a plurality of nozzles are driven simultaneously. That is, when a functional thin film is formed on the substrate, all the nozzles of the coating head or the piezoelectric elements facing a plurality of selected nozzles are driven simultaneously, and the coating liquid is discharged from the individual nozzles in such a state. It is difficult to measure the amount correctly.

  An object of the present invention is to correctly measure the discharge amount for each nozzle of the coating head even under the state where the piezoelectric elements of all nozzles or a plurality of nozzles are driven simultaneously.

  According to a first aspect of the present invention, there is provided a coating liquid coating apparatus in which a coating liquid is ejected as droplets from a plurality of nozzles arranged at predetermined intervals, and the coating liquid droplets ejected from each nozzle. Is provided for each nozzle, and a weight measuring device for measuring the weight of the coating liquid stored in the container for each nozzle.

  According to a second aspect of the present invention, in the first aspect of the present invention, a plurality of containers are provided corresponding to each nozzle, and the weight measuring device individually measures the weight of each container containing the coating liquid. Is.

  According to a third aspect of the present invention, in the second aspect of the present invention, a plurality of containers are arranged at intervals of a plurality of nozzles, and are provided in a discharge table and a weight measuring device that allow the respective containers to be arranged below the nozzles. And a measuring table that arranges the containers at intervals from each other, and a transfer unit that transfers the containers from the discharge table to the measuring table.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the plurality of containers have a rectangular parallelepiped shape and have a width that is the same as the nozzle arrangement interval in the arrangement direction to the discharge table. .

  According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the plurality of containers further have pins perpendicular to the bottom thereof, and the discharge table has a plurality of nozzles arranged with holes for inserting the pins of the respective containers. The measurement table has holes for inserting the pins of each container at intervals wider than the arrangement interval of the plurality of nozzles, and the discharge table and the measurement table have the holes in each container. Each container is arranged by inserting a pin.

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the transfer means further includes a pair of arms that sandwich the plurality of containers arranged at intervals of the plurality of nozzles from the direction orthogonal to the arrangement direction on the discharge table. Each container is operated by moving the pair of arm parts so as to narrow the relative distance while shifting each other in the arrangement direction of the containers, and horizontally rotating the containers sandwiched by the arm parts by the same angle. The distance between the pins is adjusted to the distance between the holes in the measurement table.

  According to a seventh aspect of the present invention, there is provided a control device for controlling the discharge amount of the coating liquid discharged from each nozzle for each nozzle based on the measurement result of the weight measuring device in any of the first to sixth aspects. It is intended to provide.

  The invention according to claim 8 adjusts the discharge amount of droplets from each nozzle in a coating solution coating apparatus that applies coating liquid onto a substrate by discharging the coating solution from a plurality of nozzles arranged at predetermined intervals. In the discharge amount adjustment method, the droplets of the coating liquid discharged from each nozzle are stored for each nozzle, the weight of the coating liquid for each nozzle stored is measured, and based on the measured weight of the coating liquid for each nozzle This is a discharge amount adjustment method for controlling the discharge amount of the coating liquid discharged from each nozzle for each nozzle.

  According to the present invention, it is possible to correctly measure the discharge amount for each nozzle of the coating head in a normal operation state in which the piezoelectric elements of all the nozzles are driven simultaneously.

FIG. 1 is a front view showing a coating apparatus. FIG. 2 is a plan view showing the coating apparatus. FIG. 3 is a side view showing the coating apparatus. FIG. 4 is a schematic plan view showing the transfer means. FIG. 5 is a schematic plan view showing the container on the coating liquid storage device. FIG. 6 is a schematic front view showing the process of receiving the container into the transfer means. 7A and 7B show a state in which the container is received in the transfer means, where FIG. 7A is a schematic plan view and FIG. 7B is a schematic front view. FIG. 8 is a schematic plan view showing an inclined arrangement state of the container by the transfer means. FIG. 9 is a schematic front view showing the transfer process of the container from the transfer means to the weight measuring device. 10A and 10B show a process of dropping the container onto the measuring table of the weight measuring device, where FIG. 10A is a schematic plan view and FIG. 10B is a schematic side view. FIG. 11 shows a state in which the container is dropped onto the measuring table of the weight measuring device, (A) is a schematic plan view, and (B) is a schematic side view. 12A and 12B show a state where the container is carried into the weight measuring device, where FIG. 12A is a schematic plan view, FIG. 12B is a schematic side view, and FIG. 12C is a schematic front view. FIG. 13 shows the weight measurement state of the container by the weight measuring device, (A) is a schematic side view, and (B) is a schematic front view.

  1 to 3 includes a substrate stage 13 mounted on a Y-axis direction moving guide 12 on the upper surface of a base 11, and the substrate stage 13 is moved in the Y-axis direction by a Y-axis direction moving actuator (not shown). enable. On the substrate stage 13, a glass substrate 1 used for manufacturing a liquid crystal display device is placed.

  The coating device 10 is provided with a portal frame 14 straddling the Y-axis direction moving guide 12 at a substantially central portion of the upper surface of the base 11 in the Y-axis direction. In the example, three coating heads 16 are arranged in a staggered manner along the X-axis direction orthogonal to the Y-axis direction, as shown in FIG. The coating head 16 is a functional thin film formed by an ink jet method, for example, a plurality of nozzles that discharge droplets of a coating liquid (polyimide solution) for forming an alignment film in a dot shape are arranged at predetermined intervals along the X-axis direction. is doing. The coating head 16 is provided with a piezoelectric element facing each nozzle through a flexible plate. The flexible plate is deformed by applying a voltage to each piezoelectric element, and droplets of the coating liquid are applied from the corresponding nozzle. Discharge. The coating apparatus 10 applies a voltage to all the piezoelectric elements of each coating head 16 at the same time, and the droplets of the coating liquid ejected from the nozzles corresponding to the piezoelectric elements move along with the substrate stage 13 on the substrate 1. It is applied to the upper surface at predetermined intervals.

  In the coating apparatus 10, the coating liquid discharged from each nozzle in order to uniformize the thickness of the functional thin film formed on the upper surface of the substrate 1 by the droplets of the coating liquid discharged from all the nozzles of each coating head 16. It is necessary to adjust the voltage applied to the piezoelectric element corresponding to each nozzle so that the discharge amount is measured and the discharge amount becomes equal. Therefore, the coating apparatus 10 sets the ejection amount for each nozzle of each coating head 16 in a state in which the piezoelectric elements of all the nozzles are driven simultaneously, that is, in the operation state of the same piezoelectric element as when the functional thin film is formed on the substrate 1. (This is referred to as “normal operation state”).

  The coating apparatus 10 stores a coating liquid droplet discharged from each nozzle of each coating head 16 in a container 21 for each nozzle, and stores the coating liquid storage apparatus 20 in each container 21 for each nozzle. And a weight measuring device 40 for measuring the weight of the applied coating solution. In the coating apparatus 10, the transfer means 30 is arranged between the coating liquid storage apparatus 20 and the weight measurement apparatus 40, and the container 21 is moved from the discharge base 26 of the coating liquid storage apparatus 20 to the measurement base 44 of the weight measurement apparatus 40 by the transfer means 30. Transfer to The coating device 10 includes a control device 50 that controls the discharge amount of the coating liquid discharged from each nozzle of each coating head 16 for each nozzle based on the measurement result of the weight measuring device 40. Hereinafter, the coating liquid storage device 20, the transfer means 30, the weight measuring device 40, and the control device 50 will be described in detail.

(A) Coating liquid container 20
The coating liquid storage device 20 includes an X-axis moving device 24 mounted on an X-axis direction moving guide 23 on the upper surface of the mounting bracket 22 fixed to the Y-axis direction end surface (the right end surface in FIG. 1) of the substrate stage 13, and is not shown. The X-axis moving device 24 can be moved in the X-axis direction by an X-axis direction moving actuator. A lifting device 25 is mounted on the upper surface of the X-axis moving device 24, and a discharge table 26 is installed on the lifting device 25.

  As shown in FIG. 1, the coating liquid storage device 20 has a discharge table 26 installed on the lifting device 25 having a generally inverted U-shape when viewed from the front. The number of nozzles provided is assumed to be four (in this embodiment, temporarily four). In the present embodiment, a plurality (four) of each container 21 is provided corresponding to each nozzle of one coating head 16, each container 21 is disposed at an arrangement interval of each nozzle in one coating head 16, Each container 21 can be arranged below the nozzle. In the present embodiment, the containers 21 are arranged on the discharge table 26 without a gap, and therefore have the same width (outer width) as the arrangement interval of the nozzles in the arrangement direction on the discharge table 26. The container 21 has a rectangular parallelepiped shape having a rectangular opening.

  The coating liquid storage device 20 has a vertical pin 21 </ b> A protruding downward from the bottom of each container 21, and has a through hole 26 </ b> A for inserting the pin 21 </ b> A of each container 21 on the upper surface of the discharge table 26. The discharge table 26 has the through holes 26 </ b> A at intervals of the plurality of nozzles in the coating head 16. By inserting the pins 21 </ b> A of the containers 21 into the through holes 26 </ b> A of the discharge table 26, the plurality of containers 21 are arranged on the discharge table 26 while being in contact with each other in the width direction. Here, it is assumed that the operator sets the container 21 with respect to the discharge table 26.

  As described above, the coating liquid storage device 20 is provided on the lifting device 25 that moves the discharge table 26 on the X-axis moving device 24 in the X-axis direction. Accordingly, the discharge table 26 is reciprocated in the X-axis direction by the X-axis moving device 24 and moved up and down by the lifting device 25. In the standby state, the lifting device 25 positions the discharge table 26 at the lower limit (position indicated by a solid line in FIG. 1).

  When the coating liquid storage device 20 stores the coating liquid in each container 21, the substrate stage 13 is moved in the Y-axis direction to the position indicated by the broken line in FIG. 1, and each container 21 is directly below the coating head 16 in the Y-axis direction. Position to. Simultaneously with or following this operation, the X-axis moving device 24 is driven, and each container 21 is positioned at one of the three coating heads 16, for example, one end in the X-axis direction. Directly below the coating head 16, each nozzle of the coating head 16 and each container 21 are positioned so as to face each other vertically. Here, since four containers 21 are provided, the number of nozzles of the coating head 16 is also four.

  The coating liquid storage device 20 drives the elevating device 25 while positioning each container 21 directly below the coating head 16, raises each container 21 together with the discharge table 26, and places each container 21 on the nozzle formation surface of the coating head 16. The upper ends are brought close to each other (indicated by a broken line in FIG. 3). In this state, the piezoelectric elements of all (four) nozzles of the coating head 16 are driven at the same time, and droplets of the coating liquid are ejected from each nozzle at a preset number of times simultaneously, and the coating liquid is stored in each container 21. To do. When the discharge of the coating liquid from the coating head 16 is completed, the substrate stage 13 is returned to the position shown by the solid line in FIGS. 1 and 2, and each container 21 on the coating liquid storage device 20 is transferred to the weight measuring device 40 by the transfer means 30. Transport. The operation of storing the droplets of the coating liquid discharged from the nozzles of the other coating heads 16 in each container 21 for each nozzle corresponds to the above-described operation of storing the containers 21 in the containers 21 corresponding to the nozzles of the coating head 16 this time. The measurement can be performed after the completion of the measurement of the weight of the droplet or in parallel with the measurement of the weight.

(B) Transfer means 30
As shown in FIG. 4, the transfer means 30 enables an XYZ axis moving device 31 to move in the XYZ axis direction by an XYZ axis direction moving actuator (not shown), and a fixed link 32A is fixed to the XYZ axis moving device 31. Each end of the first swing link 33A and the second swing link 33B is rotatably coupled to 32A, and the movable link 32B can be rotated to the other end of the first swing link 33A and the second swing link 33B. A parallel link mechanism is formed by the fixed link 32A, the movable link 32B, and the first and second swing links 33A and 33B. The transfer means 30 fixes the swing motor 34 to the fixed link 32A, connects the pivot 33P of the first swing link 33A pin-coupled to the fixed link 32A to the rotation shaft of the swing motor 34, and transfers the first swing. The movable link 33A and the second swing link 33B are made swingable. The transfer means 30 is fixedly provided with a pair of rearrangement arms 35 and 36 at the distal ends of the fixed link 32A and the movable link 32B. The rearrangement arms 35 and 36 are provided with air cylinders 35A and 36A, respectively. Arm portions 37 and 38 that move toward and away from each other by the air cylinders 35A and 36A are provided.

  The transfer means 30 is a pair of arm portions that sandwich a plurality of containers 21 arranged at intervals of a plurality of nozzles of the application head 16 from the direction orthogonal to the arrangement direction on the discharge table 26 of the application liquid storage device 20. 37, 38, and the pair of arm portions 37, 38 are operated so as to narrow the relative distance while being shifted from each other in the arrangement direction of the containers 21, and the containers 21 sandwiched by the arm portions 37, 38 are the same as each other. By horizontally rotating by an angle, the interval between the pins 21A of each container 21 can be adjusted to the interval between the through holes 44A provided in the measurement table 44 of the weight measuring device 40.

  In other words, the transfer means 30 swings the first swing link 33A by the swing motor 34, so that the relative positions in the longitudinal direction of the arm portions 37, 38 of the rearrangement arms 35, 36 are shifted from each other. While expanding and contracting the distance, the air cylinders 35A and 36A move the arm portions 37 and 38 only in the direction in which the facing distance is expanded and contracted, thereby expanding and contracting the facing distance.

  The transfer means 30 has the arm portions 37 and 38 of the rearrangement arms 35 and 36 as long bodies having a continuous L-shaped cross section, and supports the bottom surface of the container 21 by the L-shaped adjacent horizontal surfaces of both arm portions 37 and 38. Then, the side surface of the container 21 is sandwiched between the L-shaped opposing vertical surfaces. Elastic members 37A, 38A such as sponge and rubber are provided on the L-shaped vertical surfaces of both arm portions 37, 38.

  As shown in FIGS. 5 and 6, the transfer means 30 receives and takes out a plurality of containers 21 aligned and held on the discharge table 26 of the coating liquid storage device 20 from the discharge table 26 at a time. The operation of transferring to the measuring table 44 of the weight measuring device 40 is as follows.

  As will be described in detail later, the weight measuring device 40 enables an X-axis direction moving device 42 provided on the upper surface of the gantry 41 to be moved in the X-axis direction by an X-axis direction moving actuator (not shown). A Z-axis direction moving device 43 provided in the device 42 can be moved in the Z-axis direction by a Z-axis direction moving actuator (not shown), and a measuring table 44 is provided in the Z-axis direction moving device 43 (FIGS. 12 and 13). ). The measuring table 44 includes a plurality of grooves 45 into which the containers 21 are inserted, and has a through hole 44 </ b> A for inserting the pin 21 </ b> A of each container 21 at the center of the bottom of each groove 45. The measurement table 44 has the through holes 44 </ b> A at intervals wider than the arrangement intervals of the plurality of nozzles in the coating head 16. By inserting the pins 21 </ b> A of the container 21 into the through holes 44 </ b> A of the measurement table 44, the plurality of containers 21 are arranged on the measurement table 44 with a gap in the width direction.

  (1) The arms 37 and 38 of the rearrangement arms 35 and 36 in the transfer means 30 are in an expanded state (the first and second swing links 33A and 33B are in the state shown in FIG. The state where the portions 37 and 38 are slightly retracted from the state shown in FIG. By the XYZ axis moving device 31, the arm portions 37 and 38 of the rearrangement arms 35 and 36 are arranged below the containers 21 aligned and held on the discharge table 26 of the coating liquid storage device 20. (Fig. 6).

  Next, the arm portions 37 and 38 are raised by a predetermined distance by the XYZ axis moving device 31 to support the containers 21 on the horizontal surfaces of the arm sections 37 and 38, and the pins 21 </ b> A of the containers 21 are connected to the discharge table 26. Pull out from each through hole 26A. When the pin 21A of each container 21 is pulled out, as shown in FIG. 7, the intervals between the arm portions 37, 38 are narrowed by the air cylinders 35A, 36A, and the elastic members 37A, 38A on the vertical surfaces of the arm portions 37, 38 facing each other. The containers 21 are held in contact with the side surfaces of the containers 21. At this time, the surface with which the elastic members 37A, 38A of the arm portions 37, 38 abut against each container 21 substantially coincides with a straight extension line passing through the pivot 33P of the swing links 33A, 33B. These elastic members 37 </ b> A and 38 </ b> A constitute a part of the parallel link mechanism of the transfer means 30.

  (2) With the containers 21 held by the rearrangement arms 35 and 36 of the transfer means 30 as described in (1) above, the containers 21 are placed at the standby position of the weight measuring device 40 by the XYZ axis moving device 31. It is transferred directly above the measuring table 44.

(3) The first swing link 33A in the transfer means 30 is rotated clockwise by a predetermined amount by the swing motor 34, and the arm portions 37 and 38 of the rearrangement arms 35 and 36 are shifted as shown in FIG. The containers 21 sandwiched between the portions 37 and 38 are inclined and arranged immediately above the measurement table 44. Here, when the width of the container 21 is d and the distance between the grooves 45 of the measurement table 44 is K, the distance between the pins 21A between the adjacent containers 21 is made to coincide with the distance between the grooves 45 of the measurement table 44. The inclination angle θ of the container 21 required for the container 21 can be determined by θ = cos ⁻¹ d / K. The above-described operation of tilting each container 21 may be performed while each container 21 is transferred directly above the measurement table 44 in (2) above.

  (4) If each container 21 is inclined as described in (3) above by the arm portions 37 and 38 of the rearrangement arms 35 and 36 of the transfer means 30, the arm portions 37 and 38 are moved by the XYZ axis moving device 31. As shown in FIG. 9, the pin 21 </ b> A of each container 21 is inserted into the through-hole 44 </ b> A at the bottom of each groove 45 of the measurement table 44. Even after the pin 21A of each container 21 is inserted into the through hole 44A of the measurement table 44, the arm portions 37 and 38 continue to descend. Eventually, the lower surface of each container 21 comes into contact with the upper surface of the measurement table 44, and each container 21 is supported on the upper surface of the measurement table 44. As the arms 37 and 38 are further lowered, the containers 21 come out between the arms 37 and 38. The lowering of the arm portions 37 and 38 by the XYZ axis moving device 31 is stopped at the timing when each container 21 is completely removed from the arm portions 37 and 38. When each container 21 is supported on the upper surface of the measuring table 44 in the weight measuring device 40, the rearranging arms 35 and 36 are retracted by the XYZ axis moving device 31. The rearrangement arms 35 and 36 may stand by on the side of the coating apparatus 10 in order to take out the next container 21 from the discharge table 26 of the coating liquid storage apparatus 20.

(C) Weight measuring device 40
The weight measuring device 40 individually measures the weight of each container 21 containing the coating liquid.
As described above, the weight measuring device 40 is provided with the X-axis direction moving device 42 and the Z-axis direction moving device 43 on the gantry 41, and the Z-axis direction moving device 43 is provided with the measuring table 44. The containers 21 are just spaced apart from each other, and are provided with grooves 45 that are slightly larger in width than the containers 21 so that the containers 21 are arranged, and the pins 21A of the containers 21 enter the center of the bottoms of the grooves 45. It has a through hole 44A. Each groove 45 is formed along a direction orthogonal to the arrangement direction of the containers 21.

  The weight measuring device 40 includes an electronic balance 46 arranged below the movable range of the measuring table 44 by the X-axis direction moving device 42, and a container support table 47 arranged on the weighing table of the electronic balance 46. The container support 47 includes a pair of square pillar members 47B and 47B on both sides of the pedestal 47A, and is opened upward so that the measurement table 44 that is moved up and down by the Z-axis direction moving device 43 can enter between the pillar members 47B and 47B. A U-shape is formed, and the upper end surface of each column member 47B is provided with a rectangular cutout for receiving and supporting the lower end corner of the container 21.

  The operation of the weight measuring device 40 measuring the weight of each container 21 supported on the upper surface of the measuring table 44 is as follows.

  (1) The direction of each container 21 (FIG. 10) in an inclined arrangement supported on the upper surface of the measurement table 44 by the transfer means 30 is aligned with the direction of each groove 45 of the measurement table 44, and each container 21 is shown in FIG. As described above, it is dropped into each groove 45 of the measuring table 44.

  For this purpose, the elastic body 48 disposed on the opposite side of the X-axis direction moving device 42 across the moving path of the measuring table 44 by the X-axis direction moving device 42 shown in FIG. 12 is used (FIG. 10). That is, the elastic body 48 arranged on the movement locus of each container 21 supported on the upper surface of the measurement table 44 by the movement of the measurement table 44 in the X-axis direction by the X-axis direction moving device 42. Contact. At this time, due to the frictional force that the elastic body 48 gives to each container 21, each container 21 rotates around the pin 21 </ b> A inserted through the through hole 44 </ b> A of the measurement table 44 and changes its direction. When the direction coincides with the direction of each groove 45 of the measuring table 44, each container 21 falls into each groove 45 as shown in FIG.

  (2) When each container 21 is arranged in each groove 45 of the measuring table 44, the weight of each container 21 is measured by the electronic balance 46.

  The weight measuring device 40 measures the weight of each container 21 accommodated in each groove 45 of the measurement table 44 in order from the container 21 located at one end. Therefore, the measuring table 44 is pitch-shifted by the X-axis direction moving device 42, and the containers 21 are sequentially positioned above the container support 47 on the electronic balance 46 (FIG. 12 shows the container 21 supporting the second container 21 from the right. The state positioned above the base 47 is shown).

  When the container 21 accommodated in the groove 45 with the measurement table 44 is positioned above the container support table 47 on the electronic balance 46, the measurement table 44 is lowered by a predetermined distance by the Z-axis direction moving device 43, and FIG. As shown in FIG. 3, the container 21 is supported by the notch portion on the upper end surface of the both pillar members 47B of the container support base 47. The pin 21A of the container 21 comes out of the through hole 44A of the measuring table 44.

  When the container 21 is supported on the container support 47, its weight is measured by the electronic balance 46. The weight of the empty container 21 is measured in advance and stored in the storage unit or the like of the control device 50, and is stored in the container 21 by subtracting the stored empty weight of the container 21 from the measured value of the electronic balance 46. The weight of the applied coating solution can be calculated. Further, the calculated weight of the coating liquid is divided by the number of droplets (number of times of ejection) of the coating liquid ejected to the container 21 by the nozzle corresponding to the coating head 16 to be ejected from the nozzle corresponding to the container 21. The weight of one drop of the coating solution can be obtained.

  When the weight of the second container 21 from the right is measured, the measuring table 44 is raised by a predetermined distance by the Z-axis direction moving device 43, and the container 21 is accommodated again in the groove 45 of the measuring table 44. Further, the measuring table 44 is pitch-moved by the X-axis direction moving device 42, and the next container 21 (the third container 21 from the right) is positioned above the container support 47 on the electronic balance 46, and its weight is measured. To do. By repeating this operation, the weight of the coating solution contained in all the containers 21 is measured in order.

  (3) When the measurement of the weight of all the containers 21 is completed, the measuring table 44 is moved to the standby position (the delivery position of each container 21 by the rearrangement arms 35 and 36 of the transfer means 30) by the X-axis direction moving device 42. Let

  The rearrangement arms 35 and 36 of the transfer means 30 receive the weight-measured containers 21 in the same manner as when the containers 21 are taken out from the discharge table 26, and containers not shown for cleaning the containers 21. Transfer to discharge table. The container discharge table has a structure for supporting each container 21 in the same manner as the measurement table 44 and accommodates these containers 21. The operator takes out the container 21 accommodated in the container discharge stand and performs cleaning such as washing and drying.

  In the coating device 10, while the weight measuring device 40 measures the weight of each container 21 as described above, the operator sets a new container 21 on the discharge table 26 of the coating liquid storage device 20. Then, using the set new container 21, the droplets of the coating liquid discharged from each nozzle of the next coating head 16 are accommodated. This operation is repeated, and the discharge amount is measured for all the coating heads 16 (three coating heads 16).

(D) Control device 50
The control device 50 compares the discharge amount for each nozzle of each coating head 16 thus obtained with the discharge amount to be discharged from the nozzle, and corresponds to each nozzle so as to eliminate the difference. The drive voltage applied to the provided piezoelectric elements is individually corrected and adjusted so that the amount of the liquid droplets of the coating liquid ejected from all the nozzles of all the coating heads 16 becomes equal.

Such a coating apparatus 10 has the following effects.
A container 21 that stores droplets of the coating liquid discharged from a plurality of nozzles is provided for each nozzle, and the weight of the coating liquid stored in each container 21 is measured for each container 21 using the electronic balance 46 of the weight measuring device 40. Since the measurement is performed, even when the coating liquid is simultaneously ejected from a plurality of nozzles of the coating head 16, the ejection amount from each nozzle can be measured individually and accurately. Therefore, even under normal operating conditions, the discharge amount can be accurately adjusted for each nozzle, the uniformity of the thickness of the functional thin film formed on the substrate 1 can be improved, and the manufactured liquid crystal The quality of the display device can be improved.

  Further, when the solution discharged from the nozzles of the coating head 16 is accommodated in each container 21, the piezoelectric elements of all the nozzles are driven simultaneously as in the normal operation state. Therefore, the discharge amount of the coating liquid from each nozzle is measured under the same conditions as in the normal operation state, and the discharge amount of the coating liquid from each nozzle (drive voltage applied to each piezoelectric element) is adjusted based on this measurement result. Therefore, the discharge amount from each nozzle can be adjusted in a state where the influence of the discharge amount error caused by the difference in the operation state of the piezoelectric element is suppressed. This also makes it possible to adjust the discharge amount with high accuracy and further improve the coating accuracy.

  Further, the container 21 is transported from the coating liquid storage device 20 to the weight measuring device 40 using the transfer means 30. Thereby, since the conveyance of the container 21 from the coating liquid storage device 20 to the weight measuring device 40 is automated, the operations from the storage of the coating liquid into the container 21 to the measurement of the weight of the coating liquid stored in the container 21 are performed. Can be easily and efficiently performed. Therefore, the workability of adjusting the discharge amount from each nozzle can be improved.

  Further, the transfer device 30 takes out a plurality of solutions 21 arranged on the discharge table 26 of the coating liquid storage device 20 in a lump and delivers them together on the measurement table 44 of the weight measuring device 40. As a result, the plurality of containers 21 can be quickly transferred from the coating liquid storage device 20 to the weight measuring device 40, and the workability of adjusting the discharge amount from each nozzle can be further improved. .

  Further, the container 21 is a rectangular parallelepiped having a short opening, and the outer dimension in the width direction is formed to be the same as the arrangement interval of the nozzles. For this reason, it is possible to arrange a plurality of containers 21 at nozzle arrangement intervals simply by arranging the same number of containers 21 as the number of nozzles in contact in the width direction, thereby improving the workability of arranging the containers 21. It becomes possible.

  Further, a parallel link mechanism is adopted as the transfer means 30 and the pair of arms 37 and 38 sandwiching the plurality of containers 21 in contact with each other in the width direction are shifted relative to each other in the arrangement direction of the containers 21. It was made to operate to narrow down. By this operation, the plurality of sandwiched containers 21 are horizontally rotated by the same angle, and as a result, the interval in the arrangement direction of the pins 21A of each container 21 is widened. Accordingly, the pins 21A arranged at the same intervals as the nozzle arrangement intervals can be easily matched with the intervals between the through holes 44A provided on the measurement table 44 at intervals wider than the nozzle arrangement intervals. Therefore, the transfer of the plurality of containers 21 from the coating liquid storage device 20 to the weight measuring device 40 can be performed with good workability.

  Also, a pin 21A extending vertically downward is provided at the bottom of the container 21, a through hole 26A for inserting the pin 21A at the same interval as the arrangement interval of the plurality of nozzles is provided in the discharge table 26, and the measurement table 44 is provided in the measurement table 44. A through hole 44A for inserting the pin 21A at an interval wider than the arrangement interval of the plurality of nozzles was provided. Therefore, by simply inserting the pin 21A of the container 21 into the through holes 26A and 44A of the respective bases 26 and 44, the arrangement interval of the plurality of containers 21 can be set to a desired arrangement interval on the bases 26 and 44. Therefore, it becomes possible to arrange the plurality of containers 21 easily and quickly, and the efficiency of arranging the plurality of containers 21 can be improved.

  Further, the plurality of containers 21 were arranged on the measurement table 44 of the weight measuring device 40 so as to be separated from each other in the width direction. This makes it possible to easily measure the weight of each container 21 using the electronic balance 46, and to efficiently measure the weight of the plurality of containers 21.

  In addition, a groove 45 into which each container 21 just enters is provided in the measurement table 44, and a through hole 44A into which a pin 21A provided at the center of the bottom of each container 21 is provided in the center of the bottom of each groove 45. Thus, the container 21 can be dropped into the groove 45 simply by inserting the pin 21A of the container 21 into the through hole 44A of the measurement table 44 and rotating the container 21 around the pin 21A. Moreover, since each groove | channel 45 is formed along the direction orthogonal to the arrangement direction of the container 21 on the measurement stand 44, each container 21 dropped into each groove | channel 45 aligns along the arrangement direction. Is done. Therefore, the containers 21 can be easily and quickly aligned on the measurement table 44, and the work of measuring the weight of the coating liquid in each container 21 and, consequently, the efficiency of adjusting the discharge amount from each nozzle can be improved. be able to.

  In the above-described embodiment, when droplets of the coating liquid are ejected from the nozzles of the coating head 16 toward the container 21, all the nozzles are driven by simultaneously driving the piezoelectric elements facing all the nozzles of the coating head 16. However, the present invention is not limited to this, and the piezoelectric elements facing a plurality of nozzles selected from all the nozzles of the coating head 16 are driven simultaneously. Also good. In short, the piezoelectric elements that are simultaneously driven in the normal operation state may be driven simultaneously.

  The container 21 used for measuring the weight by the weight measuring device 40 is discharged and washed. However, the present invention is not limited to this. If the container 21 has a sufficient capacity, the container 21 can be applied. The solution may be returned to the discharge table 26 of the liquid storage device 20 and stored again by pouring the solution discharged from the nozzle into the stored coating solution. In this case, the previous weight measurement result by the weight measuring device 40 is stored in the storage unit or the like of the control device 50 for each container 21 and poured into the container 21 with the difference from the current measurement result. It is preferable to calculate the weight of the applied coating liquid.

  The present invention can correctly measure the discharge amount for each nozzle of the coating head in a normal operation state in which the piezoelectric elements of all the nozzles are driven simultaneously.

DESCRIPTION OF SYMBOLS 1 Substrate 10 Coating device 16 Coating head 20 Coating liquid storage device 21 Container 21A Pin 26 Discharge table 26A Hole 30 Transfer means 35, 36 Rearrangement arms 37, 38 Arm unit 40 Weight measuring device 44 Measuring table 44A Hole 50 Control device

Claims (8)

In a coating liquid coating apparatus that discharges coating liquid from a plurality of nozzles arranged at predetermined intervals as droplets and coats the substrate,
A container for storing droplets of the coating liquid discharged from each nozzle for each nozzle;
A coating liquid coating apparatus comprising: a weight measuring device that measures the weight of the coating liquid stored in a container for each nozzle. A plurality of containers are provided corresponding to each nozzle,
2. The coating liquid coating apparatus according to claim 1, wherein the weight measuring device individually measures the weight of each container containing the coating liquid. A plurality of containers arranged at intervals of a plurality of nozzles, and a discharge table that enables each container to be arranged below each nozzle;
The coating liquid coating apparatus according to claim 2, further comprising: a measuring table provided in the weight measuring device for arranging the containers at intervals from each other; and a transfer unit configured to transfer the containers from the discharge table to the measuring table.   The coating liquid coating apparatus according to claim 3, wherein the plurality of containers have a rectangular parallelepiped shape and have a width that is the same as the nozzle arrangement interval in the arrangement direction to the discharge table. A plurality of containers have pins perpendicular to the bottom thereof;
The discharge table has holes for inserting the pins of each container at intervals of a plurality of nozzles,
The measurement table has holes for inserting the pins of each container at intervals wider than the arrangement interval of the plurality of nozzles,
5. The coating liquid application apparatus according to claim 4, wherein the discharge table and the measurement table are configured such that the containers are arranged by inserting the pins of the containers through the holes. The transfer means includes a pair of arm portions that sandwich a plurality of containers arranged at intervals of a plurality of nozzles on the discharge table from a direction orthogonal to the arrangement direction,
The pair of arm portions are operated so as to narrow their relative distance while being shifted from each other in the arrangement direction of the containers, and the containers sandwiched by the arm portions are horizontally rotated by the same angle to each other, thereby separating the pins between the containers. The coating liquid coating apparatus according to claim 5, wherein the distance is adjusted to the interval between the holes of the measurement table.   The coating liquid coating apparatus according to any one of claims 1 to 6, further comprising a control device that controls a discharge amount of the coating liquid discharged from each nozzle for each nozzle based on a measurement result of the weight measuring apparatus. In a discharge amount adjusting method for adjusting a discharge amount of droplets from each nozzle in a coating liquid coating apparatus that discharges coating liquid as droplets from a plurality of nozzles arranged at a predetermined interval and applies them onto a substrate.
A droplet of the coating liquid discharged from each nozzle is stored for each nozzle,
Measure the weight of the coating solution for each nozzle stored,
A discharge amount adjusting method for controlling the discharge amount of the coating liquid discharged from each nozzle for each nozzle based on the measured weight of the coating liquid for each nozzle.

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