JP2010264381A - Ink discharge control method, method of manufacturing functional element ink discharge device and manufacturing device for functional element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the detection sensitivity of an ink discharge by prolonging the residence time of liquid droplets between electrodes and inhibiting the contamination of the electrodes, in the detection of an electrical discharge failure to determine whether or not ink is discharged from a nozzle by a change of an electrostatic capacity. <P>SOLUTION: An electrostatic capacity detection part 5 operates to measure the electrostatic capacity between a first electrode 3 formed at a coating head 1 and a second electrode 4 arranged opposite to the first electrode 3 in the liquid droplet discharge direction. Further, the detection part 5 detects the change of the electrostatic capacity of ink liquid droplets 30 to be discharged in response to the output of a discharge signal 8 from a nozzle 2. In addition, a discharge determination part 7 determines whether or not the ink droplets 30 are discharged from the nozzle 2, according to the detection results. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an ink discharge control method for discharging ink droplets onto a substrate in accordance with an ejection signal from a nozzle and applying the ink onto a substrate, an ink jet device, and a functional material into an ink droplet. The present invention relates to a manufacturing method and a manufacturing apparatus for a functional element applied on a substrate by a discharge means.

  An ink jet apparatus or the like is used as a printing means for forming a device by forming an organic semiconductor material or an electrode material into ink, printing the ink on a substrate, and curing the ink.

  In an inkjet apparatus, even if a signal for ejecting ink is given, a non-ejection state where ink is not ejected may occur depending on the state in the vicinity of the nozzle. Causes of non-ejection due to clogging of foreign matter in the nozzle, clogging due to agglomeration of functionalized ink material, biting of air bubbles, high viscosity of ink near the nozzle hole when ink solvent is easy to dry, etc. It becomes.

  If the non-ejection nozzle is not detected before coating and coating is performed without taking any countermeasures, a coating defect occurs, and as a result, the characteristics of the formed device may be seriously adversely affected. From such a background, a method for detecting a non-ejection nozzle of an ink jet apparatus has been proposed.

  For example, a method of optically observing ink droplets ejected from an inkjet head from a direction orthogonal to the ejection direction has been proposed. When the droplet passes through the optical path between the light emitting unit and the light receiving unit arranged with the droplet passing position interposed therebetween, the optical path is shielded and the amount of received light is reduced, thereby detecting the ejection of the droplet.

  This detection method is effective when the size of the ink jet head is relatively small, about several tens of millimeters, and the number of nozzles is small. However, if the inkjet head becomes larger than that, it is necessary to detect all nozzles in accordance with the size of the inkjet head. For this reason, it becomes necessary to arrange a plurality of optical systems, move the optical system or the ink jet head, or the distance between the optical system and the liquid drop becomes long, so a long focal point optical system is required. Will be greatly complicated.

  In addition, the diameter of inkjet droplets is as small as several tens of μm, and there is a problem that it is necessary to use a highly accurate and expensive optical system in order to detect minute droplets.

  As described above, since the conventional optical non-discharge detection method has a problem that the optical system becomes excessive, an electric non-discharge detection method has been proposed.

  FIG. 4 is a configuration diagram of a main part of a conventional electrical droplet non-ejection detection device.

  In FIG. 4, a pair of electrodes 102 is provided for each nozzle 101 in a plurality of nozzles 101, and a capacitance detection circuit including an AC power supply 103 and a current detector 104 is connected. When the ink droplet 105 is ejected from the nozzle 101, the capacitance between the electrodes 102 changes, and the current detected by the current detector 104 changes. This change in current is detected to detect ejection / non-ejection of the ink droplet 105 (see Patent Document 1).

JP 2000-318178 A

  However, the conventional configuration has a problem that the detection sensitivity is low because the change in capacitance cannot be detected only at the moment when the ink droplet passes between the electrodes.

  Further, the electrode shape is complicated, and it is difficult to recover when the surface of the nozzle or electrode is contaminated by adhesion of ink or the like, and there is a problem that the detection sensitivity is lowered due to contamination of the electrode.

  The present invention solves the above-described conventional problem, and in the electrical non-ejection detection that detects the presence or absence of ink ejection from the nozzle based on the change in capacitance, the dwell time of the droplet between the electrodes is lengthened. An object of the present invention is to provide an ink discharge control method, a functional element manufacturing method, an ink discharge apparatus, and a functional element manufacturing apparatus that improve the detection sensitivity of ink discharge by suppressing electrode contamination. .

  In order to achieve the above object, an invention according to claim 1 is an ink ejection control method for ejecting ink droplets from nozzles formed on a coating head, wherein the ink droplets are formed outside the nozzle opening of the coating head. The electrostatic capacitance between the first electrode formed and the second electrode disposed in the droplet discharge direction of the first electrode is measured, and the capacitance according to the output of the ink droplet discharge signal By detecting this change, it is determined whether or not droplets are ejected from the nozzle. By this method, the residence time of the ink droplets between the electrodes is increased, and the detection sensitivity of whether or not the ink droplets are ejected from the nozzles is improved.

  According to a second aspect of the present invention, in the ink ejection control method according to the first aspect, the second electrode has a convex shape toward the first electrode. This method increases the residence time of the liquid droplets between the electrodes and makes it difficult for the ink liquid droplets to remain on the second electrode, so that the second electrode is kept clean. Sensitivity is further improved.

  According to a third aspect of the present invention, in the ink ejection control method according to the first or second aspect, the surface of the second electrode is subjected to a water repellent treatment. This method increases the residence time of the liquid droplets between the electrodes and makes it difficult for the ink liquid droplets to remain on the second electrode, so that the second electrode is kept clean. Sensitivity is further improved.

  According to a fourth aspect of the present invention, in the ink ejection control method according to any one of the first to third aspects, the reference first electrode formed on the coating head faces the liquid droplet ejection direction of the reference first electrode. By detecting the difference between the reference capacitance between the second reference electrode and the reference capacitance between the first electrode and the second electrode, the presence or absence of droplet discharge from the nozzle is detected. It is characterized by detecting. According to this method, the staying time of the droplets between the electrodes becomes long, and a minute change in capacitance can be detected, so that the detection sensitivity of whether or not ink is ejected is further improved.

  According to a fifth aspect of the present invention, there is provided a functional element manufacturing method in which an ink droplet of a functional material is ejected from a nozzle formed on a coating head to apply the functional material on a substrate. In this case, the ink discharge control method according to any one of claims 1 to 4 is used. By this method, it is possible to manufacture a functional element having no functional material application defect and stable characteristics.

  According to a sixth aspect of the present invention, in the ink ejection device for ejecting ink droplets from the nozzle formed on the coating head, the first electrode formed outside the opening of the nozzle in the coating head; A second electrode disposed opposite to the droplet discharge direction of the first electrode, a detection unit for detecting a change in capacitance between the first electrode and the second electrode, and detection by the detection unit And a determination unit for determining the presence or absence of a droplet from the nozzle according to the result. With this device, the residence time of the ink droplets between the electrodes is increased, and the detection sensitivity of whether ink droplets are ejected from the nozzles is improved.

  According to a seventh aspect of the present invention, in the ink ejection device according to the sixth aspect, the second electrode has a convex shape toward the first electrode. This device increases the residence time of the liquid droplets between the electrodes and makes it difficult for the ink liquid droplets to remain on the second electrode, so that the second electrode is kept clean. Sensitivity is further improved.

  According to an eighth aspect of the present invention, in the ink ejection device according to the sixth or seventh aspect, the surface of the second electrode is subjected to a water repellent treatment. This device increases the residence time of the liquid droplets between the electrodes and makes it difficult for the ink liquid droplets to remain on the second electrode, so that the second electrode is kept clean. Sensitivity is further improved.

  According to a ninth aspect of the present invention, in the ink ejection device according to any one of the sixth to eighth aspects, the reference first electrode formed on the coating head is opposed to the liquid droplet ejection direction of the reference first electrode. And a reference capacitance between the reference first electrode and the reference second electrode, and a capacitance between the first electrode and the second electrode. It is characterized by detecting the difference between the two. With this device, the staying time of the liquid droplets between the electrodes is increased, and a minute electrostatic capacitance change can be detected, so that the detection sensitivity of whether or not ink is ejected is further improved.

  According to a tenth aspect of the present invention, there is provided a functional element manufacturing apparatus that ejects ink droplets of a functional material from a nozzle formed on a coating head and applies the functional material onto a substrate. The ink ejection device according to any one of claims 6 to 9 is installed in the section. With this apparatus, it is possible to manufacture a functional element having no characteristic application failure and stable characteristics.

  According to the present invention, the capacitance between the first electrode and the second electrode arranged opposite to the droplet discharge direction is measured, and the capacitance according to the output of the ink droplet discharge signal is measured. By detecting whether or not droplets are ejected from the nozzles by detecting changes in the ink, the staying time of the ink droplets between the electrodes is lengthened, and the detection sensitivity of whether or not the ink droplets are ejected from the nozzles is improved. can do.

  In addition, by implementing the present invention in the functional element manufacturing process, the occurrence of defective coating defects can be predicted in advance, and there is no defective coating of functional materials, and the manufacturing of functional elements with stable characteristics. Is realized.

The perspective view for demonstrating the manufacturing method and manufacturing apparatus of a functional element which are Embodiment 1 of this invention. 2A and 2B are explanatory diagrams of a droplet non-ejection detection function according to the first embodiment, in which FIG. 3A is a block diagram illustrating a configuration of a main part, and FIG. Explanatory drawing of the droplet non-ejection detection function in the manufacturing method and manufacturing apparatus of a functional element which are Embodiment 2 of this invention Configuration diagram of main parts of a conventional electrical droplet non-ejection detection device

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

(Embodiment 1)
FIG. 1 is a perspective view for explaining a functional element manufacturing method and manufacturing apparatus according to Embodiment 1 of the present invention.

  In FIG. 1, an application head 1 is an ink jet type application head having a plurality of nozzles (described later), and an ink liquid made of a functional material supplied to the application head 1 by an arbitrary ejection signal to each nozzle. Drops 30 can be discharged.

  There are various configurations of the application head 1. In this embodiment, ink is stored in an ink chamber communicating with a nozzle, and the ink chamber wall is vibrated by a piezoelectric element to thereby generate ink. The system that discharges is adopted. The viscosity of ink ejected by inkjet is preferably 50 mPa · sec or less. In particular, ink of about 10 mPa · sec is common.

  The substrate stage 10 is disposed to face the nozzles of the coating head 1 and moves relative to the coating head 1. On the substrate stage 10, a functional element substrate 20 is fixed by vacuum suction. For example, when different functional materials are applied in the horizontal direction as shown in the figure on the substrate 20 and the same functional material is to be applied intermittently in the depth direction, the horizontal direction of the drawing of the application head 1 is shown. By ejecting different functional material inks from the nozzles in the direction and moving the substrate stage 10 toward the front of the drawing, it is possible to apply the functional material in a desired pattern.

  The moving speed of the substrate stage 10 is determined from the total amount of ink applied to a desired location and the inkjet ejection cycle. In many cases, the discharge period is set to 100 kHz or less, and in particular, about 0.1 to 10 kHz is relatively stable regardless of ink characteristics. The ink droplet ejection speed is 5 to 10 m / s.

  As the gap between the coating head 1 and the substrate 20 is smaller, the landing accuracy is improved because it is less affected by the flying bend of the ejected ink droplet 30. The gap is set to about 0.5 mm in consideration of the parallelism of the coating head 1 and the substrate 20 and the risk in the event of foreign matter in the gap.

  As shown by the dotted line in FIG. 1, when there are non-ejection nozzles among the plurality of nozzles of the coating head 1, the coating defect A occurs, so that the performance of the functional element is impaired. Therefore, before applying ink to the substrate 20, the droplet non-ejection detection unit 40 identifies the location of the non-ejection nozzles in the nozzles of the coating head 1.

  After detecting non-ejecting nozzles, depending on the number and location of non-ejecting nozzles, perform recovery work for non-ejecting nozzles or supplement the application with other ejectable nozzles to improve the performance of functional elements. It is possible to apply an ink made of a functional material that satisfies the above.

  Next, the non-ejection detection unit 40 according to the first embodiment will be described in detail.

  2A and 2B are explanatory diagrams of a droplet non-ejection detection function according to the first embodiment. FIG. 2A is a block diagram illustrating a configuration of a main part, and FIG.

  In FIG. 2A, a plurality of nozzles 2 are formed on the coating head 1, and a first electrode 3 is formed in the vicinity of the ink ejection port of the nozzle 2. The first electrode 3 disposed outside the opening of the nozzle 2 is electrically connected although it is separated in the drawing. The second electrode 4 is installed on the droplet non-ejection detection unit 40 facing the coating head 1.

  The surface of the second electrode 4 is subjected to water repellent treatment. By this water repellent treatment, the contact angle of the ink droplet 30 is expanded to about 20 to 70 degrees, and even if the droplet adheres to the water repellent treated surface, it becomes easy to remove.

  The first electrode 3 and the second electrode 4 are arranged close to each other with a certain gap. In this embodiment, the diameter of the hole diameter of the nozzle 2 is about 20 μm. The diameter of the ejected ink droplet 30 is equal to the nozzle hole diameter, and the ink droplet 30 having a diameter of 20 μm is applied. The area of the electrodes 3 and 4 facing each other depends on the diameter of the ink droplet 30 and the gap between the first electrode 3 and the second electrode 4. In this case, the area is set to 10,000 square μm. Designing. The gap was 50 μm.

  The capacitance detection unit 5 is electrically connected to the first electrode 3 and the second electrode 4, and can measure the capacitance from the impedance between the first electrode 3 and the second electrode 4. The impedance between the electrodes 3 and 4 is measured by applying an alternating current of 1 V and 5 MHz.

  The droplet discharge control unit 6 gives a discharge signal 8 to each nozzle 2 at an arbitrary timing. In this case, the ejection signal 8 may be the drive waveform itself applied to the piezoelectric element of the ink jet, but in this embodiment, a trigger signal for generating the drive waveform is used. The length of the ejection signal 8 is 10 to 100 μs. The discharge frequency at the time of discharge determination may be several Hz, but in this embodiment, the discharge frequency is set to 10 kHz in order to shorten the inspection time.

  When the ejection signal 8 is input to the nozzle 2, the ink droplet 30 is ejected from the nozzle 2 toward the second electrode 4. When the ink droplet 30 is not ejected, the dielectric constant of the space between the first electrode 3 and the second electrode 4 is the dielectric constant of the atmosphere, but when the ink droplet 30 is ejected, the ink droplet in the atmosphere The dielectric constant changes by the amount of 30 existing. For this reason, the value of the capacitance detected by the capacitance detector 5 changes.

  As shown in FIG. 2B, the discharge determination unit 7 monitors the capacitance detected by the capacitance detection unit 5 in accordance with the discharge signal 8 transmitted from the droplet discharge control unit 6. Since a time lag occurs from the ejection signal 8 until the ink droplet 30 is actually ejected and the capacitance changes, the capacitance is monitored after a certain time after the ejection signal 8 is input. If the capacitance exceeds the threshold value, it is determined that the ink droplet 30 has been ejected from the nozzle 2. If the change in capacitance cannot be detected below the threshold, it is determined that the nozzle 2 is a non-ejection nozzle.

  By repeating the above determination for each nozzle 2 of the coating head 1, it is possible to determine the presence or absence of droplet ejection for all the nozzles 2 in the coating head 1.

  In the droplet non-ejection detection unit 40, the ejected ink adheres particularly to the periphery of the second electrode 4, but since the surface of the second electrode 4 has been subjected to water repellent treatment, it is easy to use with a cleaning unit such as a wiper. Can be washed.

  At this time, when the gap between the first electrode 3 and the second electrode 4 becomes smaller, the absolute value of the detectable capacitance becomes larger, and the ink droplet 30 with respect to the space between the first electrode 3 and the second electrode 4. Therefore, the difference in electrostatic capacitance becomes large depending on whether or not ink is ejected, which makes it easy to detect. On the other hand, since the time during which the ink droplet 30 exists between the electrodes 3 and 4 is shortened, the high-speed response of the capacitance detection unit 5 is required.

  According to the configuration of the first embodiment, the electrostatic capacitance between the first electrode 3 formed on the coating head 1 and the second electrode 4 arranged to face the droplet discharge direction of the first electrode 3. By detecting this change and determining whether or not droplets are ejected from the nozzle 2, the time during which droplets are present between the electrodes 3 and 4 is lengthened, and the detection sensitivity is improved.

(Embodiment 2)
FIG. 3 is an explanatory diagram of a droplet non-ejection detection function in the functional element manufacturing method and manufacturing apparatus according to the second embodiment of the present invention.

  In FIG. 3, the 1st electrode 3 and the 2nd electrode 4 are arrange | positioned similarly to the structure of Embodiment 1 shown in FIG. The second electrode 4 has a convex shape with a flat top surface, and the surface is water-repellent. The height of the convex shape in the second electrode 4 was 50 μm, and the area of the circular top surface was 10,000 square μm.

  In addition, a pair of reference first electrodes 13 is arranged at a location where the nozzle 2 of the coating head 1 is not formed, and the reference second electrode 14 is located at a position facing the reference first electrode 13 on the droplet non-ejection detection unit 40. Is arranged. The reference first electrode 13 and the reference second electrode 14 have the same shape as the first electrode 3 and the second electrode 4, respectively.

  The capacitance difference detection unit 15 detects a difference between the capacitance between the first electrode 3 and the second electrode 4 and the capacitance between the reference first electrode 13 and the reference second electrode 14. To do. When the ink droplets 30 are not ejected, the electrode shapes are the same, so the respective capacitances are the same, and almost no difference occurs. When the ink droplet 30 is ejected from the nozzle 2 by the ejection signal 8 from the droplet ejection controller 6, the capacitance between the first electrode 3 and the second electrode 4 changes. There is a difference between the capacitance between the reference second electrodes 14.

  The ejection determination unit 7 monitors the capacitance difference signal detected by the capacitance difference detection unit 15 in accordance with the ejection signal 8 transmitted from the droplet ejection control unit 6. If a change in capacitance difference is detected during monitoring, it is determined that the ink droplet 30 has been ejected from the nozzle 2. If no change in capacitance difference can be detected, it is determined that the nozzle 2 is a non-ejection nozzle.

  By repeating the above determination for each nozzle 2 of the coating head 1, it is possible to determine the presence or absence of ejection for all the nozzles 2 in the coating head 1.

  Since the second electrode 4 has a convex shape that is water-repellent on the surface, the ink droplet 30 that has landed on the second electrode 4 slides down the surface of the second electrode 4. By setting the structure around the second electrode 4 to a water absorption structure or a mesh structure, contamination of the second electrode 4 by the ejected ink droplets 30 can be suppressed.

  According to the configuration of the second embodiment, since the second electrode 4 has a convex shape, contamination of the second electrode 4 by the ink droplets 30 can be suppressed, so that deterioration in detection sensitivity can be prevented. Can do. In addition, by providing the reference electrodes 13 and 14, it is possible to determine the presence or absence of droplet discharge based on the difference in capacitance, and the detection sensitivity can be improved.

  The present invention can detect ejection / non-ejection of ink droplets from nozzles with high sensitivity, and can be applied not only to ink jet ink ejection but also to die coating and other coating means.

DESCRIPTION OF SYMBOLS 1 Application | coating head 2 Nozzle 3 1st electrode 4 2nd electrode 5 Capacitance detection part 6 Droplet discharge control part 7 Discharge determination part 8 Discharge signal 10 Substrate stage 13 Reference 1st electrode 14 Reference 2nd electrode 15 Capacitance difference Detection unit 20 Substrate 30 Ink droplet 40 Droplet non-ejection detection unit A Application defect

Claims (10)

  In an ink discharge control method for discharging ink droplets from nozzles formed on a coating head, a first electrode formed outside the nozzle opening of the coating head and a droplet discharge direction of the first electrode By measuring the capacitance between the second electrode and the second electrode disposed in the nozzle, and detecting a change in the capacitance according to the output of the ejection signal of the ink droplet. An ink discharge control method characterized by determining presence or absence.   The ink ejection control method according to claim 1, wherein the second electrode has a convex shape toward the first electrode.   The ink discharge control method according to claim 1, wherein the surface of the second electrode is subjected to water repellent treatment.   A reference capacitance between a reference first electrode formed on the coating head and a reference second electrode disposed facing the droplet discharge direction of the reference first electrode, the first electrode, and the reference electrode The ink ejection control according to any one of claims 1 to 3, wherein the presence or absence of droplet ejection from the nozzle is detected by detecting a difference from the capacitance with the second electrode. Method.   5. The method of manufacturing a functional element that ejects ink droplets of a functional material from a nozzle formed in an application head and applies the functional material onto a substrate, wherein the ink is applied in any one of claims 1 to 4. A method for producing a functional element, comprising using the ink ejection control method according to the item.   In an ink discharge apparatus that discharges ink droplets from nozzles formed on a coating head, a first electrode formed outside the nozzle opening of the coating head and a droplet discharge direction of the first electrode A second electrode disposed oppositely, a detection unit for detecting a change in capacitance between the first electrode and the second electrode, and the presence or absence of a droplet from the nozzle based on a detection result of the detection unit An ink ejection apparatus comprising: a determination unit that determines   The ink ejection apparatus according to claim 6, wherein the second electrode has a convex shape toward the first electrode.   8. The ink ejection apparatus according to claim 6, wherein the surface of the second electrode is subjected to a water repellent treatment.   A reference first electrode formed on the coating head; and a reference second electrode disposed opposite to the droplet discharge direction of the reference first electrode; and the detection unit includes the reference first electrode The difference between the reference capacitance between the reference second electrode and the capacitance between the first electrode and the second electrode is detected. 9. The ink ejection device according to item.   In a functional element manufacturing apparatus that discharges ink droplets of a functional material from a nozzle formed in an application head and applies the functional material onto a substrate, the ink discharge unit is provided with any one of claims 6 to 9. An apparatus for manufacturing a functional element, comprising the ink discharge device according to claim 1.

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