JP2011104475A - Method and apparatus for ejecting droplet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and apparatus for ejecting droplets whereby a measurement time can be shortened and productivity can be enhanced. <P>SOLUTION: The method of ejecting droplets includes a process of acquiring the difference of the amount of ejected liquid by each nozzle based on the amount of the ejected liquid by each nozzle in a first all-out ejection pattern wherein the liquid is ejected from all of a plurality of nozzles, relative to the amount of the ejected liquid by each nozzle in the first to the N-th ejection pattern, as the first to the N-th coefficient; a process of memorizing the first to the N-th coefficient; a process of measuring the amount of the ejected liquid by each nozzle in a second all-out ejection pattern which is new relative to the first all-out ejection pattern; a process of memorizing the mount of the ejected liquid by each nozzle in the second all-out ejection pattern; a process of calculating an estimated ejection amount of the liquid by each nozzle corresponding to the first to the N-th ejection pattern respectively based on the first to the N-th coefficient and on the amount of the ejected liquid by each nozzle in the second all-out ejection pattern; a process of memorizing the estimated ejection amount of the liquid by each nozzle corresponding to the first to the N-th ejection pattern; and a process of controlling the ejecting action of a droplet ejection head based on the estimated ejection amount of the liquid by each nozzle. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a droplet discharge method and a droplet discharge device.

  In recent years, a film forming technique using a droplet discharge method has attracted attention. According to this droplet discharge method, it is possible to arrange a minute liquid containing a film forming material at a desired position. Thereby, a fine film pattern can be formed, and patterning is facilitated as compared with the case of using a photolithography method. Further, waste of the film forming material can be reduced, the yield can be improved, and the manufacturing cost can be reduced.

  For example, a droplet discharge head used in the droplet discharge method includes a plurality of discharge units arranged in the X direction. Each discharge unit includes a liquid reservoir, a nozzle, and a piezo element that pressurizes the liquid and pushes it out of the nozzle. The liquid material is arranged by discharging the liquid material from the discharge unit while searching the film formation surface in the Y direction with such a droplet discharge head.

  In the droplet discharge head, it is important to make the discharge amount of the liquid material uniform in the plurality of discharge units. This is because if the discharge amount varies, the film thickness varies in the scanning direction. For example, when a color filter such as an image display device is manufactured by a droplet discharge method, if a variation in film thickness occurs in the color filter, this is visually recognized as stripes along the scanning direction, and display quality is impaired.

  As a method for reducing the variation in the discharge amount, a method for controlling the discharge amount of each discharge unit has been proposed. For example, in Patent Document 1, the discharge operation of a discharge unit whose droplet discharge amount is significantly different from a set value is regulated to reduce the variation in the discharge amount. In applying such a technique, it is extremely important to accurately know the discharge amount of each discharge unit. This is because knowing how much the discharge amount differs from the set value makes it possible to control the discharge amount satisfactorily.

  As one method for evaluating the discharge amount, a method of calculating the volume from the shape of the discharged liquid material is known. In this method, first, a liquid material is arranged on a test substrate by a droplet discharge head. Next, a liquid component such as a solvent or a dispersion medium contained in the arranged liquid material is evaporated to convert the solid component contained in the liquid material into a solid material. Then, the contour of the solid body on the measurement surface parallel to the inspection substrate is measured by the optical interference method. This measurement is performed on a plurality of measurement surfaces by changing the distance between the inspection substrate and the measurement surface.

  By calculating the area surrounded by the outline of the solid body on each measurement surface, the cross-sectional area of the solid body on this measurement surface is obtained. Thereby, the cross-sectional area of the solid body with respect to the distance (height) from the bottom surface of the solid body is obtained, and the volume of the solid body is obtained by integrating the cross-sectional area with the height. Since the composition of the discharged liquid is known, the volume of the liquid can be calculated backward from the volume of the solid. Thereby, the discharge amount of each discharge unit can be evaluated.

JP 2003-159787 A

However, it is difficult to efficiently evaluate the discharge amount of each discharge unit by this method for the following reason.
In this evaluation method, in order to measure the volume of the liquid material ejected from each ejection unit, an inspection pattern is drawn with the same ejection pattern as when actual drawing is performed, and the ejection amount of each ejection unit is measured. For this reason, when the discharge amount of each discharge unit fluctuates, specifically, when maintenance (head maintenance) such as a replacement operation of a droplet discharge head is performed, a test pattern must be drawn each time. Measurement takes time. In addition, when there are a plurality of ejection patterns used at the time of actual drawing, since the ejection amount varies for each ejection pattern, a plurality of measurements are required, and the measurement takes time.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a droplet discharge method and a droplet discharge device that can shorten the measurement time and improve the production efficiency. .

  In order to solve the above problems, a droplet discharge method of the present invention is a droplet discharge method using a droplet discharge head having a plurality of nozzles for discharging a liquid material, and includes all the nozzles of the plurality of nozzles. A step of measuring the discharge amount of each first nozzle in the first full discharge pattern by discharging the liquid, a step of storing the discharge amount of each nozzle in the first full discharge pattern, and the plurality of nozzles A step of measuring the discharge amount in each of the first to Nth discharge patterns by discharging the liquid material from the predetermined nozzle and storing the discharge amount for each nozzle in the first to Nth discharge patterns. The difference between the discharge amounts of the respective nozzles is determined based on the step, the discharge amount for each nozzle in the first full discharge pattern, and the discharge amount for each nozzle in the first to Nth discharge patterns. A step of calculating as a number, a step of storing the first to Nth coefficients, a step of measuring a discharge amount in a new second full discharge pattern with respect to the first full discharge pattern for each nozzle, and the first The first to N-th nozzles based on the step of storing the discharge amount for each nozzle in the two total discharge patterns, the first to N-th coefficients, and the discharge amount for each nozzle in the second total discharge pattern. Based on the step of calculating the estimated discharge amount of each nozzle corresponding to the discharge pattern, the step of storing the estimated discharge amount for each nozzle corresponding to the first to Nth discharge patterns, and the estimated discharge amount of each nozzle And a step of controlling the discharge operation of the droplet discharge head.

  According to this droplet discharge method, before actual drawing in advance, based on the discharge amount for each nozzle in the first all discharge patterns and the discharge amount for each nozzle in the first to Nth discharge patterns, the first The difference between the discharge amounts of the nozzles corresponding to the first to Nth discharge patterns among all the discharge patterns is obtained as the first coefficient. By the way, when the discharge amount changes, for example, when maintenance such as replacement of the droplet discharge head is performed at the time of actual drawing, it is necessary to draw an inspection pattern each time. However, in the present invention, the estimation of each nozzle corresponding to the first to Nth discharge patterns is based on the first to Nth coefficients and the discharge amount for each nozzle in the second all discharge pattern after maintenance. The discharge amount can be obtained. That is, it is only necessary to perform ejection from each nozzle in the entire ejection pattern and the first to Nth ejection patterns only once before drawing, and it is not necessary to measure the ejection pattern used in actual drawing. Therefore, measurement time can be shortened and production efficiency can be improved. Further, even when there are a plurality of ejection patterns used for actual drawing, a plurality of measurements are not required, the measurement time can be shortened, and the production efficiency can be improved.

  Further, in the droplet discharge method, the droplet discharge head includes a plurality of piezoelectric drive elements provided corresponding to the plurality of nozzles, and the step of controlling the discharge operation of the droplet discharge head includes: The pulse width input to the plurality of piezoelectric drive elements may be adjusted.

  According to this droplet discharge method, the discharge amount can be finely adjusted as compared with the case of adjusting the drive voltage applied to the plurality of piezoelectric drive elements. Therefore, the discharge amount from each nozzle corresponding to a predetermined discharge pattern can be made uniform.

  The droplet discharge device of the present invention has a droplet discharge head having a plurality of nozzles for discharging a liquid material, and discharges the liquid material from all nozzles of the plurality of nozzles to reduce the discharge amount in the first total discharge pattern. A first measurement unit that measures each nozzle, a first storage unit that stores a measurement result of the first measurement unit, and a first nozzle that discharges the liquid material from a predetermined nozzle of the plurality of nozzles. A second measurement unit that measures the discharge amount in each of the first to Nth discharge patterns for each nozzle, a second storage unit that stores the measurement results of the second measurement unit, and the first all discharge patterns A first calculation unit that obtains a difference in discharge amount of each nozzle as a first to Nth coefficient based on a discharge amount for each nozzle and a discharge amount for each nozzle in the first to Nth discharge patterns; A third unit for storing a calculation result of the first calculation unit; A storage unit; a third measurement unit that measures, for each nozzle, a discharge amount in a new second total discharge pattern with respect to the first total discharge pattern; and a fourth unit that stores measurement results of the third measurement unit. The estimated discharge amount of each nozzle corresponding to the first to Nth discharge patterns based on the storage unit, the first to Nth coefficients, and the discharge amount for each nozzle in the second all discharge patterns. A second calculation unit for calculating, a fifth storage unit for storing the calculation result of the second calculation unit, and a drive unit for controlling the discharge operation of the droplet discharge head based on the estimated discharge amount of each nozzle And a control device that controls the first to third measurement units, the first to fifth storage units, the first to second calculation units, and the drive unit.

  According to the droplet discharge device of the present invention, the discharge amount for each nozzle in the first all discharge patterns and the discharge for each nozzle in the first to Nth discharge patterns are controlled in advance by the control device before actual drawing. Based on the amount, the first calculation unit performs a calculation to obtain, as a first coefficient, the difference in the discharge amount of each nozzle corresponding to the first to Nth discharge patterns among the first all discharge patterns. By the way, when the discharge amount changes, for example, when maintenance such as replacement of the droplet discharge head is performed at the time of actual drawing, it is necessary to draw an inspection pattern each time. However, in the present invention, the estimation of each nozzle corresponding to the first to Nth discharge patterns is based on the first to Nth coefficients and the discharge amount for each nozzle in the second all discharge pattern after maintenance. The calculation for obtaining the discharge amount is performed by the second calculation unit. That is, it is only necessary to perform ejection from each nozzle in the entire ejection pattern and the first to Nth ejection patterns only once before drawing, and it is not necessary to measure the ejection pattern used in actual drawing. For this reason, measurement time can be shortened compared with the case where a discharge pattern is measured for every maintenance. Accordingly, it is possible to provide a droplet discharge device with excellent production efficiency. Further, even when there are a plurality of ejection patterns used for actual drawing, it is possible to provide a droplet ejection apparatus excellent in production efficiency that does not require a plurality of measurements and can shorten the measurement time.

  In the droplet discharge device, the droplet discharge head includes a plurality of piezoelectric drive elements provided corresponding to the plurality of nozzles, and the control device inputs to the plurality of piezoelectric drive elements. Control for adjusting the pulse width may be performed.

  According to this configuration, the discharge amount can be finely adjusted as compared with the case of adjusting the drive voltage applied to the plurality of piezoelectric drive elements. Therefore, the discharge amount from each nozzle corresponding to a predetermined discharge pattern can be made uniform.

It is a top view which shows schematic structure of the droplet discharge apparatus which concerns on this invention. It is a figure which shows schematic structure of a droplet discharge head. It is a block diagram of the evaluation apparatus of discharge amount. It is a block diagram which shows the control system of a droplet discharge apparatus. It is a flowchart which shows the process of the droplet discharge method which concerns on this invention. It is a figure which shows the discharge characteristic of the droplet discharge head before the variation correction of discharge amount. It is a figure which shows the discharge characteristic of the droplet discharge head before and after dispersion | variation correction | amendment of discharge amount.

  Embodiments of the present invention will be described below with reference to the drawings. This embodiment shows one aspect of the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each structure easy to understand, an actual structure and a scale, a number, and the like in each structure are different.

  FIG. 1 is a schematic plan view showing an example of a droplet discharge device according to the present invention. In this droplet discharge device, a liquid material is disposed on a workpiece (substrate to be processed) by a droplet discharge method. The liquid body to be disposed contains a solid component such as a membrane material, and the solid component remains when dried. The liquid is a dispersion (solution) or the like in which a solid component is dispersed (dissolved) in a dispersion medium (solvent). Specific examples of the liquid include color filter materials containing pigments and dyes, colloidal solutions containing metal particles that are conductive film pattern forming materials such as UV inks and metal wirings. The droplet discharge device 1 performs the droplet discharge method according to the present invention.

  As shown in FIG. 1, the droplet discharge device 1 includes a work stage 11 provided on a support base (not shown), a carriage 13 provided at a position higher than the work stage 11, and an analysis device (not shown). A storage device and a control device.

  A droplet discharge head 12 (see FIG. 2) is provided under the carriage 13 (a position overlapping the carriage 13 in plan view). Further, the work W can be placed on the upper surface of the work stage 11. The work stage 11 and the droplet discharge head 12 are electrically connected to a control device (not shown) and are controlled in position. The control device controls the discharge operation of the droplet discharge head 12. With such a configuration, it is possible to dispose a liquid material in a predetermined region of the work W from the droplet discharge head 12 while scanning the work W.

  Hereinafter, description will be made based on the XYZ orthogonal coordinate system shown in FIG. In this XYZ orthogonal coordinate system, the X direction and the Y direction are parallel to the surface direction of the work stage 11, and the Z direction is orthogonal to the surface direction of the work stage 11. Actually, the XY plane is set to a plane parallel to the horizontal plane, and the Z direction is set to the vertically upward direction. At the time of film formation, for example, after the liquid material is arranged along the main scanning direction, the position in the sub-scanning direction is adjusted, and the liquid material is arranged again along the main scanning direction. Here, the Y direction which is the moving direction of the work stage 11 is set as the main scanning direction, and the X direction which is the moving direction of the droplet discharge head 12 is set as the sub scanning direction.

  The work stage 11 includes a vacuum suction device (not shown) and the like, and can detachably fix the mounted work W. The work stage 11 is provided with a stage moving device 111. The stage moving device 111 includes a bearing mechanism such as a ball screw or a linear guide, and moves the work stage 11 in the Y direction based on a control signal input from the control device. Thereby, the mounted work W can be moved to a predetermined position in the Y direction.

  The droplet discharge device 1 includes three droplet discharge heads 12 corresponding to each of three types of color filter materials (red, green, and blue). All of the three liquid droplet ejection heads 12 are attached to the carriage 13, and the carriage 13 is provided with a carriage moving device 131. The carriage moving device 131 moves the carriage 13 in the X direction on the basis of a control signal input from the control device, or moves around the Z axis (specifically, the arrow Θ around the carriage rotation shaft 13a). Can be rotated). As a result, the droplet discharge head 12 can be moved to a predetermined position.

  Each of the three droplet discharge heads 12 includes a large number of discharge units U (see FIG. 2). Each of the discharge units U discharges a liquid based on drawing data and control signals from the control device. Three types of liquid materials that are three types of color filter materials are respectively stored in tanks (not shown). The stored liquid material is supplied to the corresponding droplet discharge head 12 through a tube (not shown) for each type.

  FIG. 2 is a diagram showing a schematic configuration of the droplet discharge head 12. 2A is a plan view showing a surface facing the workpiece W in the droplet discharge head 12, and FIG. 2B is a cross-sectional view taken along line AA in FIG. 2A.

  As shown in FIG. 2A, the droplet discharge head 12 includes a plurality of discharge units U arranged substantially orthogonal to the main scanning direction (Y direction). Here, two discharge unit groups are arranged apart from each other in the Y direction. Each of the two discharge unit groups includes a plurality (for example, 180) of discharge units U arranged along the X direction. The discharge units U constituting one discharge unit group are arranged between the discharge units U constituting the other discharge unit group. A common nozzle plate 121 is provided for the plurality of discharge units U. The nozzle plate 121 is provided with a nozzle 125 for each discharge unit U. The nozzles 125 are arranged along the arrangement direction (X direction) of the discharge units U.

  The nozzle 125 communicates with the liquid storage chamber 122. The storage chamber 122 communicates with a common reservoir 124 in a plurality of discharge units U via a liquid supply path 123. Although the detailed shape of the supply path 123 is not illustrated, the liquid material does not flow backward from the storage chamber 122 to the reservoir 124. The reservoir 124 is connected to a tube (not shown). The liquid material discharged from the discharge unit U is filled into the storage chamber 122 from a tank (not shown) via a tube, a reservoir 124, and a supply path 123.

  As illustrated in FIG. 2B, the discharge unit U includes a nozzle plate 121, a diaphragm 128, and a flow path forming substrate 127. In a region surrounded by the nozzle plate 121, the vibration plate 128, and the flow path forming substrate 127, a liquid storage chamber 122 and a supply path 123 are formed. That is, the diaphragm 128 is a part of the wall surface of the storage chamber 122.

  The diaphragm 128 is provided with a piezoelectric drive element 129 for each discharge unit U. The piezoelectric drive element 129 includes a pair of electrodes (not shown) and a piezoelectric body sandwiched between these electrodes. The control device described above supplies a drive voltage waveform to the piezoelectric drive element 129 in each of the plurality of discharge units U at a predetermined timing. The piezoelectric drive element 129 is, for example, a piezo drive element.

  When a drive voltage waveform is supplied to the piezoelectric drive element 129, due to the expansion and contraction of the piezoelectric body, a part of the diaphragm 128 on the wall surface of the storage chamber 122 is displaced in the surface direction, and the volume of the storage chamber 122 changes. When the volume of the storage chamber 122 is minimized, the liquid material corresponding to the reduced volume is pushed out from the nozzle 125 toward the workpiece W and discharged. The discharge amount of the liquid material is based on the volume change amount of the storage chamber 122, and can be adjusted by the displacement amount of the piezoelectric body, that is, the voltage value applied between the pair of electrodes or the input pulse width.

  Examples of the method for adjusting the discharge amount include a method for individually adjusting each discharge unit U, and a method for dividing a plurality of discharge units U into a plurality of groups and adjusting each group. If the adjustment is made for each group, it is not necessary to provide a drive circuit such as a circuit for generating a drive signal for each discharge unit U, and the apparatus cost can be reduced and the apparatus can be downsized.

  Further, when a plurality of ejection operations are performed on a predetermined area of the workpiece W, the total amount of the liquid material arranged in the predetermined area can be adjusted by a method of adjusting the number of ejections. As a discharge unit U that performs a discharge operation on a predetermined region, a combination of a relatively large discharge amount and a relatively small discharge amount is used to adjust the total amount of the liquid material arranged in the predetermined region. You can also.

  FIG. 3 is a diagram showing a method for evaluating the ejection amount of the droplet ejection head based on the droplet ejection apparatus 1 having the above-described configuration. FIG. 3A is a schematic diagram illustrating the configuration of the evaluation device 17 and the test piece 2 used for evaluating the discharge amount, and FIG. 3B is an enlarged view of the test piece 2.

  As shown in FIG. 3A, in the present embodiment, the ejection amount is evaluated using the test piece 2 and the evaluation device 17. The evaluation device 17 is attached to the carriage 13 of the droplet discharge device 1. The test piece 2 is fixed to the workpiece W, and the workpiece W is detachably fixed to the workpiece stage 11.

  The evaluation device 17 includes an imaging unit (CCD camera) 171, an optical system 172, an illumination unit 173, a control unit 174, and a storage unit 175. A part of the illumination light emitted from the illumination unit 173 is reflected by the surface of the imaging object arranged on the test piece 2 and enters the CCD camera 171 through the optical system 172.

  The CCD camera 171 includes a light receiving element that converts received light into electric charge, a charge coupled element that reads out the electric charge, and the like. The optical system 172 includes a single lens group or a plurality of lens groups. An image picked up by the CCD camera 171 is enlarged by, for example, about 6 to 10 times the image pickup object by the optical system 172. The illumination unit 173 is configured by ring illumination that surrounds the optical axis between the imaging object and the CCD camera 171 in an annular shape.

  As shown in FIG. 3 (b), the test piece 2 is composed of a receiving layer 21 and a base layer 22. The receiving layer 21 is provided in contact with the base layer 22, and the base layer 22 is a portion fixed to the workpiece W.

  The receiving layer 21 is made of a material that absorbs at least a part of the liquid component contained in the liquid discharged from the droplet discharge head 12. The liquid component contained in the liquid is a solvent for dissolving the solid component, a dispersion medium for dispersing the solid component, or the like. For example, when a dispersion liquid in which a solid component is dispersed in a dispersion medium is used as the liquid material, the receiving layer 21 is made of a material that absorbs the dispersion medium. When a liquid mixture of a dispersion in which a solid component is dispersed in a dispersion medium and a solution in which a solid component that is the same as or different from this solid component is dissolved in a solvent is used as the liquid material, the receiving layer 21 is A material that absorbs at least one of the dispersion and the solvent is selected. The receiving layer 21 has a substantially uniform thickness, and the thickness of the receiving layer 21 is appropriately set according to the discharge amount. For example, the evaluation accuracy can be increased by reducing the thickness of the receiving layer 21 as the discharge amount is smaller. Specifically, when the discharge amount is about several picoliters, the thickness of the receiving layer 21 can be about 10 μm.

  The base layer 22 is made of a material that does not absorb the absorbing component absorbed by the receiving layer 21 of the discharged liquid. For example, as a material for forming the base layer 22, PET (polyethylene terephthalate) can be used. The thickness of the base layer 22 is preferably set to such a thickness that the base layer 22 does not allow the absorption component to the receiving layer 21 to pass, and is preferably set to a thickness that can be stably fixed to the workpiece W. From such a viewpoint, the thickness of the base layer 22 of the present embodiment is set to about several hundred μm to several mm (here, 120 μm). With such a configuration, the liquid material is discharged from the discharge unit U of the droplet discharge head 12 toward the test piece 2, and based on the area of the liquid material arranged on the test piece 2 and the thickness of the receiving layer 21, the liquid is discharged. The discharge amount of the droplet discharge head 12 can be obtained.

  FIG. 4 is a block diagram showing a control system of the droplet discharge device. The control system of the droplet discharge device 1 includes an image processing unit (measurement unit) having various inspection cameras such as a CCD camera provided in the evaluation device 17, and a storage unit that stores various discharge amount data obtained by the image processing unit. A calculation unit that performs calculation processing based on various types of data stored in the storage unit, a drive unit that includes various drivers that drive the droplet discharge head 12, the stage moving device 111, the carriage moving device 131, and the like. And a control device for overall control of the droplet discharge device 1.

  The drive unit includes a head driver that controls the ejection operation of the droplet ejection head 12 and a motor driver that drives and controls each drive motor such as the stage moving device 111 and the carriage moving device 131. The head driver generates and applies a predetermined drive waveform in accordance with an instruction from the control device, and controls the ejection of the droplet ejection head 12. The motor driver includes, for example, an X-axis motor driver, a Y-axis motor driver, a head Θ-axis motor driver, and the like. These drive motors such as the stage moving device 111 and the carriage moving device 131 according to instructions from the control device. Drive control.

  Here, a series of actual drawing processes on the workpiece W by the droplet discharge device 1 will be briefly described. First, the workpiece W is set on the workpiece stage 11 moved to the workpiece carry-in / out area. At this time, as preparation before discharging the liquid material, a workpiece alignment operation is performed based on the image recognition result of the workpiece alignment mark by the workpiece recognition camera included in the image processing unit.

  Then, the liquid material is discharged while moving the droplet discharge head 12 relative to the workpiece W. Specifically, while moving the workpiece W in the Y direction by the stage moving device 111, main scanning for discharging and landing a liquid material from the droplet discharging head 12 on the workpiece W, and droplet discharging by the carriage moving device 131. The sub-scan that moves the head 12 in the X direction is repeatedly performed to draw the liquid material over the entire area of the work W.

(Droplet ejection method)
FIG. 5 is a flowchart showing the steps of the droplet discharge method according to the present invention. In this droplet discharge method, the amount of liquid discharged from each nozzle 125 of the droplet discharge head 12 is inspected before actual drawing processing, and maintenance (head maintenance) such as replacement work of the droplet discharge head 12 is performed. In the case of failure, the discharge amount of each nozzle 125 is estimated thereafter. When head maintenance is not performed by this droplet discharge method, the discharge amount of each nozzle at the time of actual drawing is corrected based on the discharge amount of each nozzle 125 inspected before the actual drawing process. On the other hand, when head maintenance is performed, the ejection amount of each nozzle at the time of actual drawing is corrected based on the estimated ejection amount of each nozzle 125 after the head maintenance.

  In this droplet discharge method, first, the apparatus is positioned at a predetermined position to align the apparatus. Specifically, by moving the carriage 13 in the X-axis direction by the carriage moving device 131 or by moving the work stage 11 in the Y-axis direction by the stage moving device 111, the workpiece W is removed from the droplet discharge head 12. Place directly below. Thereby, the test specimen 2 for inspection fixed on the workpiece is disposed so as to face the plurality of nozzles 125 of the droplet discharge head 12.

  Next, the liquid material is discharged from all the nozzles 125 to the test specimen 2 for inspection, and the discharge amount in the total discharge pattern (first total discharge pattern) is measured for each nozzle (step in FIG. 5). S1).

  Specifically, a drive signal is supplied to all the drive piezoelectric elements 129 corresponding to all the discharge units of the discharge units U1 to U180. As a result, the liquid material is discharged from all nozzles of the droplet discharge head 12. And the discharge amount for every nozzle in the pattern (1st all discharge pattern) by which the liquid material was discharged from all the nozzles by using the evaluation apparatus 17 is obtained.

  Next, the discharge amount for each nozzle in the first full discharge pattern is stored (step S2 in FIG. 5).

  Next, a liquid material is discharged from a predetermined nozzle among the plurality of nozzles 125 to the test specimen 2 for inspection, and the discharge amount in the first to Nth discharge patterns is measured for each nozzle (step in FIG. 5). S3). In the present embodiment, measurement is performed in the first to third ejection patterns.

  Specifically, after the total discharge amount measuring step, the carriage 13 is moved in the X-axis direction by the carriage moving device 131, or the work stage 11 is moved in the Y-axis direction by the stage moving device 111. Accordingly, a new test piece 2 on which no liquid material is disposed is disposed so as to face the plurality of nozzles 125 of the droplet discharge head 12. Next, a drive signal is supplied to the drive piezoelectric element corresponding to a predetermined discharge unit among the discharge units U1 to U180. Accordingly, the liquid material is discharged from a predetermined nozzle among the plurality of nozzles 125 of the droplet discharge head 12. Then, by using the evaluation device 17, the discharge amount for each nozzle in the pattern in which the liquid material is discharged from the predetermined nozzle (first discharge pattern, a ← 1) is obtained.

  Next, the discharge amount for each nozzle in the first discharge pattern is stored (step S4 in FIG. 5).

  FIG. 6 is a diagram showing the ejection characteristics of the droplet ejection head before the ejection amount variation correction. 6A shows the relationship between the nozzle number and the discharge amount in the first discharge pattern, FIG. 6B shows the relationship between the nozzle number and the discharge amount in the second discharge pattern, and FIG. 6C shows the third. The relationship between the nozzle number and the discharge amount in the discharge pattern is shown. In FIG. 6, the horizontal axis indicates the nozzle numbers 1 to 40 of the nozzle row, and the vertical axis indicates the discharge amount of the nozzle corresponding to each nozzle number. In addition, in FIG. 6, illustration of the nozzle numbers 41-180 is abbreviate | omitted for convenience. Further, the discharge amount of the liquid material from all the nozzles in all the discharge patterns is discrete data, but is shown by a smooth line for convenience. In this figure, as an example of the ejection characteristics of the droplet ejection head before the ejection amount variation correction, the ejection amount for each nozzle in the first to third types of ejection patterns is shown.

  As shown in FIG. 6, when the solid line before correction of the variation in the discharge amount is seen, it can be seen that the discharge amount at the left end tends to be relatively large. It can also be seen that the discharge amount for each nozzle in the predetermined discharge pattern varies. For example, when looking at a nozzle (for example, nozzle number 20 in FIG. 6A) adjacent to a nozzle that has not discharged the liquid material (for example, nozzle number 19 in FIG. 6A), the discharge amount of the liquid material increases. ing. This is because the storage chamber 122 communicates in the droplet discharge head, and no negative pressure is generated when the liquid material is discharged from the nozzle adjacent to the nozzle that does not discharge the liquid material. For this reason, it is thought that the discharge amount of a liquid material increases from the nozzle adjacent to the nozzle which has not discharged the liquid material. Further, it can be seen that when there are a plurality of ejection patterns used in actual drawing, the ejection amount varies for each ejection pattern.

  As shown in FIG. 6A, the first discharge pattern is a discharge pattern in which a liquid material is discharged from a predetermined nozzle number (for example, nozzle numbers 1 to 10, 20 to 30) among a plurality of nozzles. ing. In the first discharge pattern, a drive signal is supplied to a drive piezoelectric element corresponding to a predetermined discharge unit (for example, U1 to U10, U20 to U30) among the discharge units U1 to U180. Thereby, the liquid material is discharged from the nozzles in the first discharge pattern. Then, by using the evaluation device 17, the discharge amount for each nozzle in the first discharge pattern can be obtained.

  As shown in FIG. 6B, the second discharge pattern is a discharge pattern in which the liquid material is discharged from a predetermined nozzle number (for example, nozzle numbers 5 to 15 and 25 to 35) of the plurality of nozzles. ing. In the second discharge pattern, a drive signal is supplied to the drive piezoelectric element corresponding to a predetermined discharge unit (for example, U5 to U15, U25 to U35) among the discharge units U1 to U180. Thereby, the liquid material is discharged from the nozzles in the second discharge pattern. Then, by using the evaluation device 17, the discharge amount for each nozzle in the second discharge pattern can be obtained.

  As shown in FIG. 6C, the third discharge pattern is a discharge pattern in which a liquid material is discharged from a predetermined nozzle number (for example, nozzle numbers 10 to 20, 30 to 40) among a plurality of nozzles. Yes. In the third discharge pattern, a drive signal is supplied to drive piezoelectric elements corresponding to predetermined discharge units (for example, U10 to U20, U30 to U40) among the discharge units U1 to U180. Thereby, the liquid material is discharged from the predetermined nozzle in the third discharge pattern. Then, by using the evaluation device 17, the discharge amount for each nozzle in the third discharge pattern can be obtained.

Next, on the basis of the discharge amount for each nozzle in the first all discharge pattern and the discharge amount for each nozzle in the first discharge pattern, each nozzle corresponding to the first discharge pattern among the first all discharge patterns. The difference in discharge amount is obtained as a coefficient (first coefficient) (step S5 in FIG. 5). The equation for obtaining the coefficient (here, the first coefficient) is expressed by the following equation (1), for example.
Coefficient = INP / INA (1)
In Expression (1), INA is the discharge amount for each nozzle in the entire discharge pattern (here, the first total discharge pattern), and INP is for each nozzle in the predetermined discharge pattern (here, the first discharge pattern). Discharge amount.

  In Expression (1), the first coefficient corresponding to the first discharge pattern is obtained by substituting the discharge amount for each nozzle in the first entire discharge pattern and the discharge amount for each nozzle in the first discharge pattern. can get.

  Next, the coefficient in the first ejection pattern is stored (step S5 in FIG. 5).

  Similarly, by substituting the discharge amount for each nozzle in the second discharge pattern and the discharge amount for each nozzle in the third discharge pattern, the second coefficient corresponding to the second discharge pattern, the third A third coefficient corresponding to the ejection pattern can be obtained.

  Next, the control device determines whether or not the inspection of the first to Nth ejection patterns to be actually drawn is finished (b> N?) (Step S7 in FIG. 5). In this embodiment, since the first to third ejection patterns are inspected, when b (b ← a + 1) is 4, it is determined that the inspection of the first to third ejection patterns is completed.

  When the determination is possible, that is, when it is determined that the inspection of the first to third ejection patterns that are the actual drawing targets is completed, the control device determines whether or not the ejection amount has changed. (Step S8 in FIG. 5).

  On the other hand, when the determination is negative, that is, when it is determined that the inspection of the first to third ejection patterns to be actually drawn is not completed (for example, the second ejection pattern and the third ejection pattern When it is determined that at least one of them is insufficient), the control device causes the liquid material from each nozzle corresponding to a new ejection pattern (for example, the second ejection pattern, the third ejection pattern) with respect to the first ejection pattern. The drive control is performed so as to discharge. Then, the liquid material is discharged from the nozzle different from the nozzle corresponding to the first discharge pattern onto the test specimen 2 for inspection, and the discharge amount for each nozzle in the second discharge pattern and the nozzle in the third discharge pattern Is measured (step S3 in FIG. 5).

  Next, the discharge amount for each nozzle in the second discharge pattern and the discharge amount for each nozzle in the third discharge pattern are stored (step S4 in FIG. 5).

  Next, based on the discharge amount for each nozzle in the first all discharge pattern stored and stored in the storage unit and the discharge amount for each nozzle in the second discharge pattern, the second of the first all discharge patterns. A difference in the discharge amount of each nozzle corresponding to the discharge pattern is obtained as a coefficient (second coefficient). Further, based on the discharge amount for each nozzle in the first full discharge pattern and the discharge amount for each nozzle in the third discharge pattern, the discharge of each nozzle corresponding to the third discharge pattern in the first full discharge pattern The amount difference is obtained as a coefficient (third coefficient) (step S5 in FIG. 5). Note that the second coefficient and the third coefficient are obtained by Expression (1).

  Next, the second coefficient in the second ejection pattern and the third coefficient in the third ejection pattern are stored (step S6 in FIG. 5). Through the above steps, the discharge amount for each nozzle in the estimated discharge pattern that has been insufficient is stored, and all of the discharge patterns to be actually drawn are stored.

  By the way, when maintenance (head maintenance) such as replacement work of the droplet discharge head 12 is performed at the time of actual drawing, the discharge amount for each nozzle in all discharge patterns varies before and after the head maintenance. For this reason, in the conventional droplet discharge method, it is necessary to draw an inspection pattern every time the head maintenance is performed, and the measurement takes time. Further, when there are a plurality of ejection patterns used at the time of actual drawing, since the ejection amount varies for each ejection pattern, a plurality of measurements are required for each head maintenance, and the measurement takes time.

  Therefore, in the droplet discharge method according to the present invention, when head maintenance is not performed, the discharge of each nozzle at the time of actual drawing is performed based on the first to third coefficients obtained before the actual drawing process. The amount is corrected. On the other hand, when head maintenance is performed, the ejection amount of each nozzle at the time of actual drawing is corrected based on the ejection amount for each nozzle estimated after the head maintenance. Specifically, in the present embodiment, the control device determines whether or not the ejection amount has changed (whether or not head maintenance has been performed) (step S8 in FIG. 5).

  When the determination is negative, that is, when it is determined that head maintenance is not performed, the control device causes the discharge amount at each nozzle to approach a predetermined appropriate amount based on the first to third coefficients. The ejection operation of the droplet ejection head 12 is controlled (step S13 in FIG. 5).

  On the other hand, when the determination is made, that is, when it is determined that the head maintenance has been performed, the control device performs drive control so that the liquid material is discharged from all the nozzles of the droplet discharge head after the head maintenance. Then, the liquid material is discharged from all of the plurality of nozzles 125 of the droplet discharge head 12 after the head maintenance to the test specimen 2 for inspection, and the discharge amount in the total discharge pattern (second total discharge pattern) is set to the nozzle. Measurement is performed every time (step S9 in FIG. 5).

  Specifically, a drive signal is supplied to all the drive piezoelectric elements 129 corresponding to all the discharge units of the discharge units U1 to U180 after the head maintenance. Thereby, the liquid material is discharged from all the nozzles of the droplet discharge head 12 after the head maintenance. And the discharge amount for every nozzle in the pattern (2nd all discharge pattern) by which the liquid material was discharged from all the nozzles by using the evaluation apparatus 17 is obtained. The discharge amount for each nozzle in the second full discharge pattern is different from the discharge amount for each nozzle in the first full discharge pattern measured before head maintenance.

  Next, the discharge amount for each nozzle in the second entire discharge pattern is stored (step S10 in FIG. 5).

  Next, the nozzles corresponding to the first to third ejection patterns are estimated without ejecting the liquid material from the predetermined nozzles of the plurality of nozzles 125 after the head maintenance to the test specimen 2 for inspection. The discharge amount is calculated (step S11 in FIG. 5).

  Specifically, based on the first to third coefficients stored in the storage unit by the driving signal from the control device and the discharge amount for each nozzle in the second total discharge pattern, the first to first The estimated discharge amount of each nozzle corresponding to the discharge pattern 3 is calculated.

Next, the estimated discharge amount for each nozzle corresponding to the first to third discharge patterns is stored (step S12 in FIG. 5).
Through the above steps, the estimated discharge amount for each nozzle corresponding to the insufficient discharge pattern is stored, and all the estimated discharge amounts corresponding to the first to third discharge patterns to be actually drawn are stored.

  Then, the control device controls the discharge operation of the droplet discharge head 12 based on the estimated discharge amount of each nozzle so that the discharge amount at each nozzle approaches a predetermined appropriate amount (step S13 in FIG. 5).

  Specifically, based on the estimated discharge amount for each nozzle corresponding to the first discharge pattern, the second discharge pattern, and the third discharge pattern, the discharge amount at the plurality of nozzles approaches a predetermined appropriate value. The drive voltage applied to the piezoelectric drive element and the input pulse width are adjusted. That is, when the discharge amount at each nozzle is larger than a predetermined appropriate value, adjustment is performed to reduce the drive voltage applied to the piezoelectric drive element and the input pulse width. On the other hand, when the discharge amount at each nozzle is smaller than a predetermined appropriate value, adjustment is performed to increase the drive voltage applied to the piezoelectric drive element and the input pulse width.

  FIG. 7 is a diagram showing the ejection characteristics of the droplet ejection head before and after correcting the variation in ejection amount. In FIG. 7, the horizontal axis indicates nozzle numbers 1 to 180 of the nozzle row, and the vertical axis indicates the discharge amount from the nozzle corresponding to each nozzle number. As shown in FIG. 7, when the solid line before the correction of the variation in the ink discharge amount is seen, it can be seen that the ink discharge amount tends to be relatively large at the nozzles at both ends and the central portion.

  As shown in FIG. 7, after the correction, the variation in the discharge amount of the entire droplet discharge head is significantly reduced after the correction. If the droplet discharge head with the corrected discharge amount is used for forming a color filter, a color filter with a uniform film thickness can be formed, and unevenness due to film thickness variations can be prevented.

  According to the droplet discharge method and the droplet discharge apparatus 1 of the present invention, the discharge amount for each nozzle in the first full discharge pattern and the first to third before the actual drawing in advance and before the actual drawing in advance. Based on the discharge amount for each nozzle in the discharge pattern, the difference between the discharge amounts of the nozzles corresponding to the first to third discharge patterns among the first all discharge patterns is obtained as the first coefficient. By the way, when the discharge amount changes, for example, when maintenance such as replacement of the droplet discharge head is performed at the time of actual drawing, it is necessary to draw an inspection pattern each time. However, in the present invention, the estimation of each nozzle corresponding to the first to third ejection patterns is based on the first to third coefficients and the ejection amount for each nozzle in the second entire ejection pattern after maintenance. The discharge amount can be obtained. That is, it is only necessary to perform ejection from each nozzle in the entire ejection pattern and the first to third ejection patterns only once before drawing, and it is not necessary to measure the ejection pattern used at the time of actual drawing. Therefore, measurement time can be shortened and production efficiency can be improved. Further, even when there are a plurality of ejection patterns used for actual drawing, a plurality of measurements are not required, the measurement time can be shortened, and the production efficiency can be improved.

  In the above-described embodiment, as the control of the discharge operation of the droplet discharge head performed by the control device, the drive voltage applied to the piezoelectric drive element or the input pulse width is adjusted. Is preferably adjusted using the input pulse width. Thereby, compared with the case where the drive voltage to be applied is adjusted, the discharge amount can be finely adjusted, so that the discharge amount from each nozzle corresponding to the predetermined discharge pattern can be made uniform.

  In the above embodiment, an example of the second discharge pattern and the third discharge pattern in addition to the first discharge pattern has been described. However, the present invention is not limited to this. Furthermore, more discharge patterns such as a fourth discharge pattern and a fifth discharge pattern may be added. Thus, even when a discharge pattern equal to or greater than the fourth discharge pattern is used, the present invention can shorten the measurement time and improve the production efficiency.

  In the above embodiment, an example in which a dispersion in which a solid component is dispersed in a dispersion medium is used as a liquid, but a solution in which a solid component is dissolved in a solvent may be used as the liquid. As the liquid, a mixed liquid of a dispersion obtained by dispersing a solid component in a dispersion medium and a solution obtained by dissolving the same or different solid component in a solvent may be used. Even when such a liquid material is used, it is possible to measure the discharge amount of a predetermined pattern with high efficiency according to the present invention.

DESCRIPTION OF SYMBOLS 1 ... Droplet discharge apparatus, 12 ... Droplet discharge head, 125 ... Nozzle, 129 ... Piezoelectric drive element

Claims (4)

A droplet discharge method using a droplet discharge head having a plurality of nozzles for discharging a liquid material,
A step of discharging the liquid material from all nozzles of the plurality of nozzles and measuring a discharge amount in the first total discharge pattern for each nozzle;
Storing a discharge amount for each nozzle in the first total discharge pattern;
A step of discharging the liquid material from a predetermined nozzle of the plurality of nozzles and measuring a discharge amount in the first to Nth discharge patterns for each nozzle;
Storing a discharge amount for each nozzle in the first to Nth discharge patterns;
Based on the discharge amount for each nozzle in the first all discharge pattern and the discharge amount for each nozzle in the first to Nth discharge patterns, the difference in discharge amount of each nozzle is obtained as the first to Nth coefficients. Process,
Storing the first to Nth coefficients;
Measuring a discharge amount in a new second full discharge pattern with respect to the first full discharge pattern for each nozzle;
Storing a discharge amount for each nozzle in the second total discharge pattern;
Calculating an estimated discharge amount of each nozzle corresponding to the first to Nth discharge patterns based on the first to Nth coefficients and the discharge amount for each nozzle in the second all discharge pattern;
Storing an estimated discharge amount for each nozzle corresponding to the first to Nth discharge patterns;
Controlling the discharge operation of the droplet discharge head based on the estimated discharge amount of each nozzle;
A droplet discharge method comprising: The droplet discharge head is provided with a plurality of piezoelectric drive elements provided corresponding to the plurality of nozzles,
2. The droplet discharge method according to claim 1, wherein, in the step of controlling the discharge operation of the droplet discharge head, a pulse width input to the plurality of piezoelectric drive elements is adjusted. A droplet discharge head having a plurality of nozzles for discharging a liquid;
A first measurement unit that discharges the liquid material from all nozzles of the plurality of nozzles and measures the discharge amount in the first total discharge pattern for each nozzle;
A first storage unit for storing a measurement result of the first measurement unit;
A second measuring unit that discharges the liquid material from a predetermined nozzle of the plurality of nozzles and measures the discharge amount in the first to Nth discharge patterns for each nozzle;
A second storage unit for storing a measurement result of the second measurement unit;
Based on the discharge amount for each nozzle in the first all discharge pattern and the discharge amount for each nozzle in the first to Nth discharge patterns, the difference in discharge amount of each nozzle is obtained as the first to Nth coefficients. A first computing unit;
A third storage unit for storing a calculation result of the first calculation unit;
A third measuring unit that measures, for each nozzle, a discharge amount in a new second full discharge pattern with respect to the first full discharge pattern;
A fourth storage unit for storing a measurement result of the third measurement unit;
A second for calculating an estimated discharge amount of each nozzle corresponding to the first to Nth discharge patterns based on the first to Nth coefficients and the discharge amount for each nozzle in the second all discharge patterns; An arithmetic unit;
A fifth storage unit for storing a calculation result of the second calculation unit;
A drive unit that controls the discharge operation of the droplet discharge head based on the estimated discharge amount of each nozzle;
A control device for controlling the first to third measurement units, the first to fifth storage units, the first to second calculation units, and the drive unit;
A droplet discharge apparatus comprising: The droplet discharge head is provided with a plurality of piezoelectric drive elements provided corresponding to the plurality of nozzles,
The liquid droplet ejection apparatus according to claim 3, wherein the control device performs control to adjust a pulse width input to the plurality of piezoelectric driving elements.

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