Liquid dispensing device, method for controlling a liquid dispensing device, substrate processing device, and method for manufacturing articles

Abstract

This technology offers advantages in reducing the time required for recovery processing of faulty nozzles and the amount of liquid used. [Solution] The liquid dispensing device comprises a dispensing element that dispenses liquid, a driver that applies a drive signal to the dispensing element to drive the dispensing element, and a control unit that controls the driver. The drive signal includes a plurality of data sets having pulse patterns in which the frequency decreases in steps for each time segment of a predetermined length. Based on the dispensing failure state of the dispensing element, the control unit selects a data set from the plurality of data sets and controls the driver to supply it to the dispensing element in order from the one with the highest pulse frequency to perform preliminary dispensing.

Description

Technical Field

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[0001] The present invention relates to a liquid ejection device, a control method for a liquid ejection device, a substrate processing device, and an article manufacturing method.

Background Art

[0002] In recent years, when manufacturing various functional elements, attempts have been made to form patterns or films by applying a material for a functional element onto a substrate using an inkjet device (patterning). Patterning using an inkjet device has advantages such as high material usage efficiency because on-demand patterning is possible, being a non-vacuum process and thus the manufacturing device being relatively small, and being able to coat a large area at high speed.

[0003] By the way, in the above-described inkjet device, during dot pattern formation or standby, troubles such as ejection failures and quality disturbances may occur due to foreign matter adhering in the flow path or near the nozzle opening, thickening of the ink, sedimentation of ink components, electrophoresis phenomena, etc.

[0004] Patent Document 1 discloses a technique of starting with a small amount of preliminary ejection and performing medium and large amounts of preliminary ejection until recovery can be confirmed. Patent Document 2 discloses performing ink ejection while increasing and decreasing the driving frequency of a recording head in order to remove bubbles in the recording head.

Prior Art Documents

Patent Documents

[0007] The present invention provides a technology that is advantageous in reducing the time required and the amount of liquid used for recovery processing of faulty nozzles. [Means for solving the problem]

[0008] According to one aspect of the present invention, a liquid dispensing device is provided, comprising: a dispensing element for dispensing liquid; a driver for applying a drive signal to the dispensing element to drive the dispensing element; and a control unit for controlling the driver, wherein the drive signal includes a plurality of types of datasets having pulse patterns in which the frequency decreases in steps for each time segment of a predetermined length, and the control unit controls the driver to select a dataset from the plurality of types of datasets based on the dispensing failure state of the dispensing element and supply it to the dispensing element in order from the one with the highest pulse frequency to perform preliminary dispensing. [Effects of the Invention]

[0009] According to the present invention, for example, it is possible to provide a technology that is advantageous in reducing the time required for recovery processing of defective nozzles and the amount of liquid used. [Brief explanation of the drawing]

[0010] [Figure 1] A diagram showing the configuration of an inkjet printer. [Figure 2] A diagram showing an example of a control configuration for a single dispensing head. [Figure 3] A diagram illustrating the relationship between residual signal waveforms and ejection failure conditions. [Figure 4] This diagram illustrates a method for determining nozzle dispensing defects using residual signal waveforms. [Figure 5]A diagram illustrating the recovery process using preliminary vomiting. [Figure 6] A diagram showing an example of a pulse pattern supplied to the nozzle. [Figure 7] A diagram illustrating examples of multiple types of datasets. [Figure 8] A flowchart showing the operation sequence of an inkjet printer. [Figure 9] A schematic diagram showing an example of material application for a functional element. [Modes for carrying out the invention]

[0011] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0012] Referring to Figure 1, the configuration and operating principle of the inkjet apparatus 1 (substrate processing apparatus) will be explained. The inkjet apparatus 1, which can function as a substrate processing apparatus for processing substrates such as display panels and semiconductors, applies material for functional elements onto the substrate to form patterns and films. In the specification and drawings, as shown in Figure 1, directions are indicated in an XYZ coordinate system in which the plane parallel to the plane on which the substrate 2 is placed is the XY plane. The inkjet apparatus 1 includes a substrate stage 3 that holds and moves a substrate 2, for example, a display panel substrate 2. The substrate 2 may be appropriately selected from glass substrates, plastic substrates, etc., depending on the product to be manufactured. The substrate 2 is typically a plate-shaped member, but is not limited to a specific shape as long as it can function as a substrate. For example, the substrate 2 may be a deformable film or a circular substrate. The substrate 2 on the substrate stage 3 has a pixel area 201 for applying ink to form an array of display pixels. An evaluation area 202 is located on the substrate stage 3, where ink is experimentally ejected to evaluate the state of the ink. Alternatively, the evaluation area 202 may be provided in a specific region of the substrate 2. In this specification, "ink" refers to a liquid used to form patterns or films on the substrate 2. While there are no particular limitations on the components of the ink in this specification, for example, a liquid containing a solute and a solvent for forming an organic film can be used.

[0013] The inkjet device 1 includes an ejection head 5 (liquid ejection device) capable of ejecting ink droplets 4 toward predetermined positions on a substrate 2, and an ink supply system 6 that supplies ink from an ink tank 7 to the ejection head 5. The ejection head 5 is equipped with a plurality of nozzles 19 (ejection elements) for ejecting ink. The ink tank 7 may be located inside the inkjet device 1 or outside the inkjet device 1. The inkjet device 1 may also include a recovery unit 8 that performs cleaning or other processes on the ejection nozzles of the ejection head 5 to restore the ejection characteristics.

[0014] When substrate 2 is mounted on substrate stage 3, placement errors may occur. Also, due to various manufacturing processes, substrate 2 may experience shape distortion in the XY direction. Therefore, the inkjet device 1 may be equipped with an alignment scope 9 to measure the position of substrate 2 and the amount of distortion of substrate 2. In order to perform alignment measurement over the entire surface of substrate 2, the alignment scope 9 and substrate stage 3 are driven relative to each other in the XY direction. That is, the alignment scope 9 and / or substrate stage 3 are driven in the XY direction. In addition, there are variations in the thickness of the substrates mounted on substrate stage 3. Therefore, when ink is ejected by the ejection head 5 while scanning substrate stage 3 in the Y direction, variations in the landing position of ink droplets on substrate 2 may occur due to variations in the thickness of substrate 2. Therefore, the inkjet device 1 may also be equipped with a height sensor 10 to measure the position (height) of substrate 2 in the Z direction. In order to perform height measurement over the entire surface of substrate 2, the height sensor 10 and substrate stage 3 are driven relative to each other in the XY direction. In other words, the height sensor 10 and / or the substrate stage 3 are driven in the XY direction.

[0015] The main control unit 11 controls each part of the inkjet device 1 to oversee the patterning on the substrate 2. The main control unit 11 may be composed of, for example, a PLD (Programmable Logic Device) such as an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), a general-purpose computer with a program installed, or a combination of all or part of these.

[0016] In one example, a plurality of ejection heads 5 are arranged in the X direction and the Y direction respectively, and by individually controlling the ejection of ink droplets from each ejection head, ink can be applied to the pixel area 201 on the substrate 2 in a desired distribution. FIG. 2 shows an example of the control configuration of one ejection head 5. The ejection head 5 may include a plurality of nozzles 19. Each of the plurality of nozzles 19 constitutes an ejection element including a piezoelectric element (ejection energy generating element). Each of the plurality of nozzles 19 is connected to a driver D that drives the piezoelectric element via a flexible cable F. The driver D is connected to an ejection control unit C (control unit). The ejection control unit C sends a command (recovery processing command) for recovering an abnormal nozzle among the plurality of nozzles 19 to the driver D. The driver D applies a drive signal to the piezoelectric element of the abnormal nozzle according to the received command and executes a recovery process. Note that the function of the ejection control unit C may be realized by the main control unit 11.

[0017] During the formation or standby of a dot pattern using a plurality of nozzles 19, troubles such as ejection failure and quality disturbance may occur due to foreign matter adhering in the flow path or near the nozzle opening, thickening of the ink, sedimentation of ink components, electrophoresis phenomenon, etc. This trouble is caused by the comprehensive action of various factors such as ejection time, flow path shape, distance from the electrode, and standby time without ejection. The degree of trouble may vary for each nozzle.

[0018] For the recovery process from problems such as air sucking or severe nozzle clogging that cannot be recovered by preliminary ejection, the recovery unit 8 is used. However, the recovery process using the recovery unit 8 requires a long time and the amount of ink used in the recovery process becomes very large. Therefore, the recovery process using the recovery unit 8 is only carried out at the timing set as regular maintenance. In normal operation, preliminary ejection from a plurality of nozzles 19 is appropriately carried out in the preliminary ejection area 20 to recover the ejection failure nozzles to a normal state.

[0019] The ejection failure status of each nozzle can be confirmed using the associated signal (residual signal waveform) measured after the generation of a specific pressure wave. Specifically, the ejection control unit C activates the piezoelectric element by applying a specific pulse signal to the piezoelectric element via the driver D. A specific pressure wave is generated in the piezoelectric element as it is activated. If the piezoelectric element is functioning correctly, this pressure wave will cause ink to drip from the nozzle. At this time, the pressure wave generated in the piezoelectric element causes distortion in the piezoelectric element, and an electrical signal corresponding to that distortion is generated. This electrical signal is called the "residual signal". The ejection control unit C detects this electrical signal and determines the ejection failure status of the piezoelectric element based on the detected electrical signal.

[0020] Figure 3(a) shows an example of a residual signal waveform. The horizontal axis represents time, and the vertical axis represents potential. The residual signal waveform shown in Figure 3(a) is a reference signal waveform that indicates the state of a nozzle capable of stable discharge. If a signal waveform equivalent to this is obtained, the nozzle is judged to be in a normal state. As the nozzle's discharge malfunction progresses, this waveform changes as shown below.

[0021] As the nozzle's dispensing failure progresses, the residual signal waveform changes from the solid line state to the dashed line state, as shown in Figure 3(b). Specifically, the initial peak position shifts from T0 to T1 and T2, and the signal period also lengthens. As the dispensing failure progresses, the residual signal waveform transitions from dashed line 1 to dashed line 2. When a pre-dispensing at an appropriate frequency is performed on this nozzle in the dispensing failure state to return it to a normal state, the residual signal waveform returns to the original reference waveform (solid line waveform) in Figure 3(a).

[0022] The recovery process using pre-discharge will be explained with reference to Figures 4(a) to 4(d). Figure 4(a) shows the residual signal waveforms indicating a discharge failure state for each of the five nozzles A to E. The discharge failure state differs for each nozzle, and as shown in Figure 4(a), the residual signal waveforms also differ for each nozzle. The process to recover from the different discharge failure states for each nozzle, as shown in Figure 4(a), to the normal state (reference waveform) shown in Figure 3(a) is performed using pre-discharge according to the following procedure. (1) Determine a preliminary discharge frequency that is suitable for the defective state of the nozzle, and apply a pulse signal of that frequency to the nozzle. (2) Apply the pre-discharge frequencies in order, starting with the one that best suits the nozzle with the worst condition.

[0023] By performing the two steps described above, a nozzle with a dispensing defect can be restored. In one example, if there are multiple nozzles with different dispensing defects as shown in Figure 4(a), the dispensing control unit C classifies the dispensing defects into multiple (three) groups as shown in Figures 4(b), (c), and (d). Subsequently, the dispensing control unit C performs preliminary dispensing at a frequency appropriate to the dispensing defect for each group via the driver D. For example, as shown in Figure 4(d), if the first peak is within area I including T2, the dispensing control unit C determines that nozzle E is in a severe dispensing defect state. As shown in Figure 4(c), if the first peak is within area II including T1, the dispensing control unit C determines that nozzle D is in a moderate dispensing defect state. Also, as shown in Figure 4(b), if the first peak is within area III including T0, the dispensing control unit C determines that nozzles A, B, and C are in a mild dispensing defect state. Note that since nozzle A is in a normal state, the waveform of nozzle A in Figure 4(b) is the same as the reference waveform in Figure 4(a).

[0024] In this way, the discharge control unit C determines the discharge failure state based on the position of the first peak in the residual signal waveform and controls the driver D to perform a preliminary discharge by supplying a pulse signal of a frequency appropriate for the discharge failure state to the nozzle. For severely discharge-failed nozzles where the first peak of the residual signal waveform is in area I, a high-frequency preliminary discharge is appropriate. For moderately discharge-failed nozzles where the first peak of the residual signal waveform is in area II, a medium-frequency preliminary discharge is appropriate. For mildly discharge-failed nozzles where the first peak of the residual signal waveform is in area III, a low-frequency preliminary discharge is appropriate. In one example, high frequency refers to a frequency in the range of 10kHz to 50kHz. Medium frequency refers to a frequency in the range of 1kHz to 10kHz. Low frequency refers to a frequency in the range of 100Hz to 1kHz.

[0025] Referring to Figures 5(a) to 5(d), the procedure for recovering nozzle E, which is in a severe dispensing failure state as shown in Figure 4(d), will be explained. Figure 5(a) shows the same signal waveform as Figure 4(d). As shown in Figure 5(a), the first peak position of the signal waveform indicating the failure state of nozzle E is in area I, so first, a high-frequency pre-discharge is performed. As a result of this high-frequency pre-discharge, the residual signal waveform, as shown in Figure 5(b), has a shorter signal period and the first peak position is earlier, transitioning to area II. In response to the transition of the first peak position to area II, a medium-frequency pre-discharge is performed. As a result of this medium-frequency pre-discharge, the residual signal waveform, as shown in Figure 5(c), has a further shortened signal period and the first peak position is even earlier, transitioning to area III. In response to the transition of the first peak position to area III, a low-frequency pre-discharge is performed. As a result of this low-frequency pre-discharge, the residual signal waveform returns to the reference waveform as shown in Figure 5(d), and the recovery process is completed.

[0026] According to the recovery processes shown in Figures 5(a) to (d) above, the degree of recovery by each recovery process can be predicted without checking the residual signal waveform. For example, driver D may perform preliminary discharge using a dataset (a combination of high-frequency, medium-frequency, and low-frequency discharge frequencies) that has a pulse pattern in which the frequency decreases in steps for each time segment of a predetermined length, as shown in Figure 6. In the example in Figure 6, the pulse pattern may include the following pulse sequence. (1) A first pulse train of high frequency (e.g., 50 kHz) in the first time segment to address severe nozzle dispensing failure, (2) In the second time segment following the first time segment, a second pulse train of medium frequency (e.g., 5 kHz) corresponding to moderate nozzle discharge failure, (3) A third pulse train of low frequency (e.g., 500 Hz) in the third time segment following the second time segment to address minor nozzle dispensing failures.

[0027] However, when applying the same dataset shown in Figure 6 to multiple nozzles with different discharge failure conditions, the recovery capability is low, especially for nozzles where the discharge failure condition and the pre-discharge frequency do not match. To obtain the same recovery effect for multiple nozzles with different discharge failure conditions, as shown in Figure 7, the driver D prepares multiple types of datasets with different frequencies in advance. That is, the pulse pattern frequencies differ among the multiple types of datasets. Each dataset may be stored in the driver D's internal or external memory and read out for use, or each dataset may be generated as needed. The discharge control unit C controls the driver D to supply each of the multiple types of datasets to the nozzle in order from the highest pulse pattern frequency to the highest to perform pre-discharge. In the example in Figure 7, set 1 includes a 50kHz pulse train in the first time segment, a 5kHz pulse train in the second time segment, and a 500Hz pulse train in the third time segment. Set 2 includes a 30kHz pulse train in the first time segment, a 3kHz pulse train in the second time segment, and a 300Hz pulse train in the third time segment. Set 3 includes a 10kHz pulse train in the first time segment, a 1kHz pulse train in the second time segment, and a 100Hz pulse train in the third time segment. By supplying the pulse patterns to the nozzle in order from the highest frequency, i.e., Set 1, Set 2, and Set 3, to perform a preliminary discharge, the nozzle can be reliably restored in a short time.

[0028] Note that in the examples in Figures 6 and 7, the frequencies of the signals constituting each set are set to three types, but this is not limited to this. The frequencies of the signals constituting each set may be set to two types, or four or more types. The recovery status of the nozzles may be checked, and if multiple unrecovered nozzles occur, the number of types of signals constituting each set may be increased.

[0029] Referring to Figure 8, the operation sequence of the inkjet device 1 will be explained. In S801, the main control unit 11 controls a substrate transport device (not shown) to load the substrate 2 into the inkjet device 1. In S802, the ejection control unit C performs a recovery determination of the multiple nozzles 19 of the ejection head 5. The recovery determination is performed by determining whether the first peak position of the residual signal waveform is equivalent to that of the reference waveform. Specifically, the ejection control unit C applies a specific pulse signal to the nozzle via the driver D to operate the nozzle, and detects an electrical signal corresponding to the distortion of the nozzle caused by the pressure wave generated as a result of the nozzle's operation as a residual signal. Subsequently, the ejection control unit C determines the nozzle's ejection failure state based on a comparison between the first peak position of the residual signal waveform and the peak position of the reference waveform. Note that the recovery determination of the multiple nozzles 19 may be performed before ink ejection. If any nozzle is determined to have an ejection failure in this recovery determination, in S803, the ejection control unit C performs the above-described nozzle recovery process on that nozzle. In other words, during the nozzle recovery process, the discharge control unit C acquires multiple types of datasets, each having a pulse pattern with a progressively lower frequency for each predetermined time segment. Here, the pulse patterns differ among the multiple types of datasets. Subsequently, the discharge control unit C supplies each of the multiple types of datasets to the nozzle in order from the one with the highest pulse frequency to perform preliminary discharge. Note that the nozzle recovery determination and recovery process described above may be performed by the main control unit 11.

[0030] In S804, the main control unit 11 controls the substrate stage 3 and the alignment scope 9 to measure the alignment of the substrate 2. In S805, the main control unit 11 controls the substrate stage 3 and the height sensor 10 to measure the height of the substrate 2. Note that the order of the alignment measurement in S804 and the height measurement in S805 may be reversed. Information regarding the position, amount of strain, and height of the substrate 2 obtained from the alignment measurement and height measurement is stored, for example, in the memory of the main control unit 11. The main control unit 11 obtains ejection control information based on pixel data that includes information such as the pixel arrangement and size of pixels formed on the substrate 2. The ejection control information includes information indicating the target ink coating distribution in the pixel area 201 and evaluation area 202 on the substrate 2.

[0031] In S806, the discharge control unit C performs a recovery determination on the multiple nozzles 19 of the discharge head 5. The recovery determination is performed by determining whether the first peak position of the residual signal waveform is equivalent to that of the reference waveform, as described above. If any nozzle is determined to be defective in this recovery determination, in S807, the discharge control unit C performs the nozzle recovery process described above on the nozzle in question.

[0032] In step S808, the main control unit 11 drives the ejection head 5 and the substrate stage 3 synchronously, and controls the ejection of ink droplets by the ejection head 5 based on the target coating distribution via the ejection control unit C. To form a large number of functional elements on the substrate using the inkjet device 1, the coating area to be coated with ink and the ejection head 5 are scanned relative to each other to coat the material for the functional elements. Figure 9 shows a schematic diagram illustrating the coating of such functional element material. In Figure 9, the substrate surface 101 is the surface of the substrate 2 on which the functional elements 102 are formed. The arrows 103, 104, 105, and 106 indicate the scanning direction. Since Figure 9 is a schematic diagram, only 7 × 5 functional elements 102 are shown, but in reality, a very large number of functional elements can be formed.

[0033] In S809, the main control unit 11 determines whether or not ejection to the target coating distribution has been completed based on the ejection control information. If ejection is not completed, the process returns to S806; if ejection is completed, the process proceeds to S810. In S810, the main control unit 11 controls a substrate transport device (not shown) to remove the substrate 2 from the inkjet device 1.

[0034] <Embodiment of Article Manufacturing Method> The article manufacturing method in the embodiment of the present invention is suitable for manufacturing articles such as display panels for organic ELs, microdevices such as semiconductor devices, and elements having fine structures. The article manufacturing method of this embodiment includes the steps of: ejecting a liquid onto a substrate using the above-mentioned inkjet apparatus to form an ejected liquid film; drying the substrate on which the ejected liquid film has been formed to obtain a substrate on which a dried film has been formed; and manufacturing an article from the substrate on which the dried film has been formed. Furthermore, such an article manufacturing method includes other well-known steps (such as firing, cooling, washing, oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.). The article manufacturing method of this embodiment is advantageous over conventional methods in at least one of the performance, quality, productivity, and production cost of the article.

[0035] The disclosures herein include at least the following: a liquid dispensing device, a method for controlling a liquid dispensing device, a substrate processing device, and a method for manufacturing articles. (Item 1) A dispensing element that dispenses liquid, A driver that drives the ejection element, A control unit that controls the driver, Equipped with, The driver is configured to provide multiple types of datasets, each having a pulse pattern in which the frequency decreases in steps for each time segment of a predetermined length, wherein the frequencies of the pulse patterns differ among the multiple types of datasets. The control unit controls the driver to supply each of the multiple types of datasets to the discharge element in order from the one with the highest pulse pattern frequency to the one with the highest frequency to perform preliminary discharge. A liquid dispensing device characterized by the following features. (Item 2) The aforementioned multiple types of datasets are A first dataset having a pulse pattern in which the frequency decreases in steps for each time segment of a predetermined length, A second dataset having a pulse pattern in which the frequency decreases in steps for each time segment of a predetermined length, wherein the frequency in each time segment is lower than the frequency of the first dataset, A third dataset having a pulse pattern in which the frequency decreases in steps for each time segment of a predetermined length, wherein the frequency in each time segment is lower than the frequency of the second dataset, A liquid dispensing device according to item 1, characterized by including the following: (Item 3) The aforementioned pulse pattern is A high-frequency first pulse train corresponding to a severe ejection failure of the ejection element in the first time segment, In the second time segment following the first time segment, a second pulse train of medium frequency corresponding to a moderate discharge failure of the discharge element, In the third time segment following the second time segment, a low-frequency third pulse train corresponding to a minor ejection failure of the ejection element, A liquid dispensing device according to item 1 or 2, characterized by including the following: (Item 4) The liquid dispensing device according to item 3, characterized in that the high frequency is a frequency in the range of 10 kHz to 50 kHz, the medium frequency is a frequency in the range of 1 kHz to 10 kHz, and the low frequency is a frequency in the range of 100 Hz to 1 kHz. (Item 5) The aforementioned ejection element includes a piezoelectric element, The control unit, A specific pulse signal is applied to the piezoelectric element via the driver to activate the piezoelectric element, and an electrical signal corresponding to the strain of the piezoelectric element caused by the pressure wave generated as a result of the operation of the piezoelectric element is detected. If it is determined that the ejection element is malfunctioning based on the detected electrical signal, the driver is controlled to perform preliminary ejection using the multiple types of datasets. A liquid dispensing device according to any one of items 1 to 4, characterized by the above. (Item 6) A control method for a liquid dispensing device equipped with a dispensing element that dispenses liquid, A step of acquiring multiple types of datasets having pulse patterns in which the frequency decreases in steps for each time segment of a predetermined length, wherein the frequencies of the pulse patterns in the multiple types of datasets are different from each other. A step of supplying each of the aforementioned multiple types of datasets to the discharge element in order from the highest pulse frequency of the pulse pattern to the discharge element to perform preliminary discharge, A control method characterized by having the following features. (Item 7) A substrate processing apparatus for processing substrates, A stage that holds and moves the substrate, A liquid dispensing device according to any one of items 1 to 5, which dispenses liquid onto the substrate held by the stage, A substrate processing apparatus characterized by including (Item 8) The process involves discharging a liquid onto a substrate using the substrate processing apparatus described in item 7, A process of processing the substrate from which the liquid has been discharged, A method for manufacturing articles, comprising manufacturing an article from the processed substrate.

[0036] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of symbols]

[0037] 1: Inkjet device (substrate processing device), 2: Substrate, 3: Substrate stage, 5: Discharge head (liquid discharging device), 9: Alignment scope, 10: Height sensor, 11: Main control unit, 19: Nozzle (discharge element)

Claims

1. A dispensing element that dispenses liquid, The ejection element is provided with a driver that applies a drive signal to drive the ejection element, A control unit that controls the driver, Equipped with, The drive signal includes multiple types of datasets having pulse patterns in which the frequency decreases in steps for each time segment of a predetermined length. The control unit, based on the discharge failure state of the discharge element, selects a dataset from the plurality of datasets and controls the driver to supply the pulse patterns to the discharge element in order from the highest frequency to the lowest frequency to perform preliminary discharge. A liquid dispensing device characterized by the following features.

2. The aforementioned ejection element includes a piezoelectric element, The control unit, A specific pulse signal is applied to the piezoelectric element via the driver to activate the piezoelectric element, and an electrical signal corresponding to the strain of the piezoelectric element caused by the pressure wave generated as a result of the operation of the piezoelectric element is detected. Based on the detected electrical signal, the discharge element determines whether there is a discharge malfunction. The liquid dispensing device according to feature 1.

3. The aforementioned multiple types of datasets are A first dataset having a pulse pattern in which the frequency decreases in steps for each time segment of a predetermined length, A second dataset having a pulse pattern in which the frequency decreases in steps for each time segment of a predetermined length, wherein the frequency of the second dataset is lower than the frequency of the first dataset in each time segment, The liquid dispensing device according to claim 1, characterized by including the following:

4. The aforementioned multiple types of datasets are further, A third dataset having a pulse pattern in which the frequency decreases in steps for each time segment of a predetermined length, the third dataset including a third dataset in which the frequency in each time segment is lower than the frequency of the second dataset, The liquid dispensing device according to feature 3.

5. The aforementioned pulse pattern is In the first time segment, the first pulse train and, In the second time segment following the first time segment, a second pulse train having a frequency lower than the frequency of the first pulse train, A liquid dispensing device according to claim 1, characterized by including the following:

6. The aforementioned pulse pattern is The third time segment following the second time segment includes a third pulse train having a frequency lower than the frequency of the second pulse train. The liquid dispensing device according to feature 5.

7. The liquid dispensing device according to claim 6, characterized in that the frequency of the first pulse train is in the range of 10 kHz to 50 kHz, the frequency of the second pulse train is in the range of 1 kHz to 10 kHz, and the frequency of the third pulse train is in the range of 100 Hz to 1 kHz.

8. The liquid dispensing device is a device capable of dispensing the liquid onto a substrate. The control unit controls the driver to perform preliminary discharge in areas where the substrate is not provided. The liquid dispensing device according to feature 1.

9. A control method for a liquid dispensing device equipped with a dispensing element that dispenses liquid, A process of acquiring multiple types of datasets having pulse patterns in which the frequency decreases in stages for each time segment of a predetermined length, A step of selecting a dataset from the multiple types of datasets based on the discharge failure state of the discharge element, A step of supplying the pulse patterns of the selected dataset to the discharge element in order from the highest frequency to the highest frequency to perform preliminary discharge, A control method characterized by having the following features.

10. A substrate processing apparatus for processing substrates, A stage that holds and moves the substrate, A liquid dispensing device according to any one of claims 1 to 8, which dispenses liquid onto the substrate held by the stage, A substrate processing apparatus characterized by including

11. A step of forming a liquid film on a substrate by discharging a liquid onto a substrate using the substrate processing apparatus described in claim 10, A step of drying the substrate on which the liquid film has been formed to obtain the substrate on which a dried film has been formed, A method for manufacturing an article, comprising manufacturing an article from the substrate on which the dried film is formed.

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