Liquid discharge device, method of manufacturing article, control method, information processing device, generation method, and program

Abstract

To provide a technique advantageous for accurately controlling a plurality of discharge parts of a liquid discharge device.SOLUTION: A liquid discharge device includes: a liquid chamber having a discharge port; a plurality of discharge units each having a piezoelectric element that applies pressure to the inside of the liquid chamber to discharge liquid droplets from the discharge port; a detection unit that detects, for each of the plurality of discharge units, a signal representing vibration in the liquid chamber caused by operating the piezoelectric elements; and a control unit for controlling each of the plurality of discharge units, wherein in the plurality of discharge units, the signals detected by the detection unit are different from each other, and discharge states of droplets are different from each other according to the difference between the signals, the control unit generates correlation information between the signal and the discharge state in advance from a difference between the plurality of discharge units with respect to the set of the signal and the discharge state, and the discharge state changed due to the temporal deterioration is estimated for each discharge unit from the detection result of the detection unit by using the correlation information in common in the plurality of discharge units.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a liquid ejection device, an article manufacturing method, a control method, an information processing device, a generation method, and a program. [Background technology]

[0002] In recent years, when manufacturing various functional elements, attempts have been made to form patterns on a substrate (patterning) using a liquid ejection device that ejects (supplies) the liquid that will be the material of the functional element as droplets onto the substrate by the inkjet method. Such patterning using a liquid ejection device has the advantages of being highly efficient in the use of materials because it allows on-demand patterning, being a non-vacuum process that allows the manufacturing equipment to be relatively small, and being able to coat a large area at high speed.

[0003] Meanwhile, various display methods have been proposed for display devices, and in recent years, the development of display devices using organic EL elements has been actively promoted. Since the organic EL material for producing the organic EL elements is expensive, a liquid ejection device that is efficient in material usage and capable of coating a large area at high speed may be used. Recently, a color conversion section containing a quantum dot material or a display device equipped with quantum dots as a light-emitting element has been attracting attention. For example, a liquid ejection device having a liquid ejection head that ejects liquid such as ink may be used to produce a color conversion section containing a quantum dot material. The liquid ejection head is provided with a plurality of ejection sections each having a pressure chamber (liquid chamber) having an ejection hole and a pressure generating element (piezoelectric element) that generates pressure in the liquid chamber to eject droplets from the ejection hole. In such a liquid ejection head, the piezoelectric element deteriorates due to repeated driving of the piezoelectric element or an applied voltage that maintains the piezoelectric element in a displaced state for a long time and causes a state in which stress is continuously applied. The deterioration of the piezoelectric element leads to a decrease in the amount of displacement of the piezoelectric element, and therefore, even if the same applied voltage is applied, the ejection speed and ejection volume of droplets decrease, resulting in a problem of deterioration in print quality.

[0004] To solve this problem, Patent Document 1 describes a method of detecting residual vibrations in a pressure chamber that occur when an inspection signal is supplied to a pressure generating element, and correcting the ejection signal that is supplied to the pressure generating element to eject liquid based on the detection results. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-32622 A Summary of the Invention [Problem to be solved by the invention]

[0006] Conventionally, information showing the correlation between the residual vibration and the ejection speed or ejection volume of droplets was generated individually for each of the multiple ejection parts. However, in order to generate the information for one of the multiple ejection parts, it is necessary to obtain a set of the residual vibration and the ejection speed or ejection volume of droplets at least twice at a time interval during which the pressure generating element of the one ejection part deteriorates with time to a certain extent. In this case, the ejection signal cannot be corrected until the pressure generating element of the one ejection part deteriorates with time to a certain extent and the information can be generated, making it difficult to control the multiple ejection parts with high accuracy.

[0007] SUMMARY OF THE PRESENT EMBODIMENTS In view of the above, an object of the present invention is to provide an advantageous technique for controlling a plurality of ejection sections in a liquid ejection device with high precision. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, a liquid ejection device as one aspect of the present invention comprises a plurality of ejection sections, each having a liquid chamber with an ejection hole and a piezoelectric element that applies pressure into the liquid chamber to eject droplets from the ejection hole, a detection section that detects, for each of the plurality of ejection sections, a signal representing vibrations in the liquid chamber caused by operating the piezoelectric element, and a control section that controls each of the plurality of ejection sections, wherein the signals detected by the detection section are different from each other in the plurality of ejection sections, and the ejection states of droplets from the ejection holes are different from each other depending on the differences in the signals, and the control section generates correlation information in advance indicating a correlation between the signal and the ejection state from the differences between the plurality of ejection sections regarding the pairs of the signal and the ejection state, uses the correlation information in common to the plurality of ejection sections, estimates the ejection state that has changed due to deterioration over time for each ejection section from the detection results of the detection section, and controls each of the plurality of ejection sections based on the estimated result of the ejection state.

[0009] Further objects and other aspects of the present invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings. Effect of the Invention

[0010] According to the present invention, for example, it is possible to provide an advantageous technique for precisely controlling a plurality of ejection sections in a liquid ejection device. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing an example of the configuration of a liquid ejection device according to an embodiment of the present invention; [Diagram 2] 1 is a flowchart showing an operation sequence of a liquid ejection device. [Diagram 3] Schematic diagram showing an example of coating of materials for functional elements [Figure 4] 2A and 2B are schematic diagrams illustrating an example of the configuration of a discharge head. [Diagram 5] A diagram showing the waveform of the vibration signal (voltage) detected by the detection unit. [Figure 6]FIG. 13 is a diagram for explaining the correlation between the amplitude of a vibration signal and the ejection state in one ejection section; [Figure 7] FIG. 13 is a diagram showing correlation information generated from differences among a plurality of ejection units with respect to group data. [Figure 8] 1 is a flowchart showing an example of control of a plurality of ejection units in an ejection head. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0013] In this specification and the accompanying drawings, directions are shown in an XYZ coordinate system in which a plane parallel to a surface on which a substrate is placed is the XY plane. The directions parallel to the X-axis, Y-axis, and Z-axis in the XYZ coordinate system are the X direction, the Y direction, and the Z direction, respectively, and the rotation around the X-axis, the Y axis, and the Z axis are θX, θY, and θZ, respectively. Control and drive (movement) regarding the X-axis, Y-axis, and Z-axis respectively mean control or drive (movement) regarding the direction parallel to the X-axis, the direction parallel to the Y axis, and the direction parallel to the Z axis. In addition, control or drive regarding the θX-axis, θY-axis, and θZ-axis respectively mean control or drive regarding the rotation around an axis parallel to the X-axis, the rotation around an axis parallel to the Y axis, and the rotation around an axis parallel to the Z axis.

[0014] <Liquid discharge device> With reference to FIG. 1, the basic configuration and operation principle of the liquid ejection device 1 will be described. The liquid ejection device 1 is a device that ejects (supplies, applies) a liquid, which is a material of a functional element, onto a substrate to form a pattern, and functions as a substrate processing device that processes substrates such as display panels and semiconductors. For example, the liquid ejection device 1 can be used to manufacture display devices such as flat panel displays and OLED (Organic Light Emitting Diode) devices. In this specification, the term "ink" refers to a liquid that is ejected onto a substrate by the liquid ejection device 1 to form a pattern or film on the substrate. In this specification, there is no particular limitation on the components of the ink, but for example, a liquid containing a solute and a solvent for forming an organic film can be used as the ink.

[0015] The liquid ejection device 1 includes a substrate stage 3 that holds and moves a substrate 2 of, for example, a display panel. The substrate 2 may be a glass substrate, a plastic substrate, or the like, appropriately selected depending on the target 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 base. For example, the substrate 2 may be a deformable film or a disk-shaped substrate. In addition, the substrate 2 on the substrate stage 3 is provided with a pixel area 201 for applying ink to form an array of a large number of display pixels, and an evaluation area 202 into which ink is test-ejected to evaluate the state of the ink.

[0016] The liquid ejection device 1 includes an ejection head 5 capable of ejecting ink droplets 4 toward the substrate 2, an ink tank 7 for storing ink, and an ink supply system 6 for supplying ink from the ink tank 7 to the ejection head 5. The ejection head 5 includes a plurality of ejection units 20 for ejecting ink droplets 4 in accordance with a drive signal, and the ejection of the ink droplets 4 in each ejection unit 20 is individually controlled by a control unit 11. This allows ink to be supplied (applied) to a pixel area 201 on the substrate 2 in a desired distribution. A detailed configuration of the ejection head 5 will be described later. Here, the ink tank 7 may be disposed inside the liquid ejection device 1, or may be disposed outside the liquid ejection device 1. The liquid ejection device 1 may also include a recovery unit 8 for performing a cleaning process or the like on the ejection head 5 to recover the ejection characteristics.

[0017] When the substrate 2 is mounted on the substrate stage 3, a placement error may occur. Furthermore, as the substrate 2 undergoes various manufacturing processes, shape distortion may occur in the substrate 2 in the XY directions. For this reason, the liquid ejection device 1 is provided with an alignment scope 9 that measures the position of the substrate 2 and the amount of distortion of the substrate 2. In order to perform alignment measurement for the entire surface of the substrate 2, the alignment scope 9 and the substrate stage 3 are driven relatively in the XY directions. Furthermore, the substrate 2 mounted on the substrate stage 3 has a variation in thickness. Therefore, when ink is ejected from the ejection head 5 while scanning the substrate stage 3 in the Y direction, the adhesion position (landing position) of the ink droplets 4 on the substrate 2 may vary due to the variation in thickness of the substrate 2. For this reason, the liquid ejection device 1 may also have a height sensor 10 that measures the position (height) of the substrate 2 in the Z direction. In order to perform height measurement for the entire surface of the substrate 2, the height sensor 10 and the substrate stage 3 are driven relatively in the XY directions.

[0018] The liquid ejection device 1 of this embodiment may further include a detection unit 14 and a droplet measurement unit 15. The detection unit 14 detects a signal representing vibrations in the liquid chamber caused by operating the piezoelectric element for each ejection unit 20 of the ejection head 5. A detailed configuration of the detection unit 14 will be described later. The droplet measurement unit 15 measures the ejection state of the ink droplet 4 in each ejection unit 20 of the ejection head 5. The ejection state of the ink droplet 4 may include at least one of the ejection speed and the ejection volume of the ink droplet 4 ejected from the ejection hole of each ejection unit 20. The ejection state of the droplet may include the twist angle when the ink droplet 4 is ejected.

[0019] Here, an example will be described in which the droplet measuring unit 15 measures the discharge speed of the ink droplets 4 discharged from each discharge unit 20 as a discharge state. In this case, the droplet measuring unit 15 images the ink droplets 4 multiple times with different timings during flight of the ink droplets 4 discharged from each discharge unit 20, and can measure the discharge speed from the difference in the position (height) of the ink droplets 4 in the multiple images obtained thereby. Alternatively, the droplet measuring unit 15 images the ink droplets 4 attached to the substrate 2 by scan discharge, which causes each discharge unit 20 to discharge the ink droplets 4 while scanning the substrate 2, and can measure the discharge speed from the amount of deviation between the attached position of the ink droplets 4 on the substrate 2 and the target position. The example in which the droplet measuring unit 15 measures the discharge volume of the ink droplets 4 discharged from each discharge unit 20 as a discharge state is similar to the example in which the discharge speed of the ink droplets 4 is measured. That is, the droplet measuring unit 15 may measure the ejection volume by capturing an image of the ink droplet 4 ejected from each ejection unit 20 while the ink droplet 4 is in flight, or may measure the ejection volume by capturing an image of the ink droplet 4 adhered to the substrate 2.

[0020] The control unit 11 is configured by a computer (information processing device) having a processor such as a CPU (Central Processing Unit) and a storage unit such as a memory, and controls each unit of the liquid ejection device 1 to centrally control patterning on the substrate 2. The control unit 11 may be configured by, for example, a PLD (abbreviation for Programmable Logic Device) such as an FPGA (abbreviation for Field Programmable Gate Array), an ASIC (abbreviation for Application Specific Integrated Circuit), a general-purpose computer with a built-in program, or a combination of all or part of these.

[0021] <Operation sequence of liquid ejection device> Next, the operation sequence of the liquid ejection device 1 will be described with reference to FIG. 2. In step S101, the control unit 11 controls a substrate transport device (not shown) to load the substrate 2 into the liquid ejection device 1. Specifically, the control unit 11 controls a substrate transport device (not shown) to load the substrate 2 onto the substrate stage 3, and causes the substrate stage 3 to hold the substrate 2. Next, in step S102, the control unit 11 performs recovery determination for each ejection unit 20 of the ejection head 5. The recovery determination is to determine whether or not an ejection abnormality occurs in each ejection unit 20 of the ejection head 5, that is, whether or not a recovery process needs to be performed for each ejection unit 20. If there is an ejection unit 20 that is determined to have an ejection abnormality in this recovery determination, the process proceeds to step S103, and the control unit 11 executes a recovery process for each ejection unit 20 of the ejection head 5. The recovery process may include, for example, a process of recovering the ejection characteristics of the ejection head 5 by performing a cleaning process or the like on the ejection head 5 by the recovery unit 8.

[0022] In step S104, the control unit 11 performs alignment measurement of the substrate 2 by controlling the substrate stage 3 and the alignment scope 9. In step S105, the control unit 11 performs height measurement of the substrate 2 by controlling the substrate stage 3 and the height sensor 10. The alignment measurement in step S104 and the height measurement in step S105 may be performed in reverse order. Information on the position, distortion amount, and height of the substrate 2 obtained by the alignment measurement and the height measurement is stored in, for example, a memory in the control unit 11. The control unit 11 obtains ejection control information based on pixel data including information such as pixel arrangement and pixel size formed on the substrate. The ejection control information includes information indicating a target ink application distribution in the pixel area 201 and the evaluation area 202 on the substrate 2.

[0023] In step S106, the control unit 11 performs a recovery determination for each ejection unit 20 of the ejection head 5. If any ejection unit 20 is determined to have an ejection abnormality in this recovery determination, the process proceeds to step S107, where the control unit 11 executes a recovery process for each ejection unit 20 of the ejection head 5. Steps S106 to S107 are the same processes as steps S102 to S103 described above.

[0024] In step S108, the control unit 11 performs discharge control (discharge process) of the ink droplets 4 by the discharge head 5 based on the target application distribution while synchronously scanning (driving) the discharge head 5 and the substrate stage 3. In order to form a large number of functional elements on the substrate 2 using the liquid discharge device 1, the control unit 11 discharges the material of the functional element (ink droplets 4) from each discharge unit 20 of the discharge head 5 while relatively scanning the application area where the ink is applied and the discharge head 5 in the discharge process. FIG. 3 shows a schematic diagram for explaining the application of the material of such a functional element. In FIG. 3, the substrate surface 101 is the surface of the substrate 2 on which the functional elements 102 are formed. Since FIG. 3 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.

[0025] In step S109, the control unit 11 determines whether or not the discharge process has been completed for the substrate 2. If the discharge process for the substrate 2 has not been completed, the process returns to step S106, and if the discharge process for the substrate 2 has been completed, the process proceeds to step S110. In step S110, the control unit 11 controls a substrate transport device (not shown) to transport the substrate 2 out of the liquid discharge device 1 (on the substrate stage 3).

[0026] <Discharge head> Next, a configuration example of the ejection head 5 will be described. Fig. 4 is a schematic cross-sectional view showing an enlarged portion of the ejection head 5. The ejection head 5 of this embodiment includes a common liquid chamber 51 and a module substrate 52. The common liquid chamber 51 is a liquid chamber that stores ink 53 to be supplied to a plurality of ejection sections 20 provided in the module substrate 52. The ink 53 is supplied to the common liquid chamber 51 from an ink tank 7 via an ink supply system 6. The module substrate 52 has a plurality of ejection sections 20 formed thereon, arranged along a direction (e.g., X direction) intersecting (orthogonal to) the scanning direction (Y direction) of the substrate 2.

[0027] Each of the multiple ejection units 20 includes a liquid chamber 22 having an ejection hole 21, and a piezoelectric element 23 that applies pressure to the liquid chamber 22 to eject ink droplets 4 from the ejection hole 21. The liquid chamber 22 of each ejection unit 20 is provided with a communication hole 24 that communicates with a common liquid chamber 51, and ink 53 stored in the common liquid chamber 51 is supplied through the communication hole 24. The opening area of ​​the ejection hole 21 in each ejection unit 20 is smaller than the opening area of ​​the communication hole 24, and the opening area (cross-sectional area) is the smallest in the flow path of the ink 53 in the ejection head 5. In each ejection unit 20 configured in this manner, the control unit 11 provides a predetermined drive signal (e.g., a pulse signal) to the piezoelectric element 23 to operate the piezoelectric element 23, so that the ink 53 in the liquid chamber 22 is ejected from the ejection hole 21 as ink droplets 4.

[0028] Here, the multiple ejection units 20 may be understood to be configured as one structure (module substrate 52). Furthermore, the ejection head 5 including the common liquid chamber 51 and the module substrate 52 configured by the multiple ejection units 20 is replaceable. Furthermore, the number of the multiple ejection units 20 can be set appropriately.

[0029] <Detection section> Next, a configuration example of the detection unit 14 will be described. The detection unit 14 detects a signal (hereinafter, sometimes referred to as a vibration signal) representing vibration in the liquid chamber 22 caused by actuating the piezoelectric element 23 by applying a predetermined inspection signal (e.g., a pulse signal) to the piezoelectric element 23 for each ejection unit 20. Specifically, when pressure is generated in the liquid chamber 22 by applying an inspection signal to the piezoelectric element 23 to actuate the piezoelectric element 23, vibration occurs in the liquid chamber 22 due to the pressure, and the vibration remains in the liquid chamber 22 for a while. The vibration remaining in the liquid chamber 22 in this way is called "residual vibration," and the detection unit 14 detects the back electromotive force (voltage, current) generated in the piezoelectric element 23 by the residual vibration in the liquid chamber 22 for each ejection unit 20 as a vibration signal. That is, the detection unit 14 may include a voltage sensor or a current sensor provided for each ejection unit 20. The vibration signal detected by the detection unit 14 correlates with the ejection state of the ink droplets 4 from the ejection holes 21, and is used to estimate the ejection state of the ink droplets 4 that has changed due to deterioration over time of the piezoelectric elements 23 for each ejection unit 20. Although omitted in Fig. 4, the detection unit 14 is configured to detect the vibration signal for each of the multiple ejection units 20 individually.

[0030] <Method of estimating discharge state> Next, a method for estimating the ejection state of the ink droplets 4 that has changed due to the aging deterioration of the piezoelectric element 23 based on the detection result of the detection unit 14 will be described. For example, the control unit 11 operates the piezoelectric element 23 by providing a predetermined test signal (e.g., a pulse signal) to each ejection unit 20, and causes the detection unit 14 to detect a vibration signal obtained from the piezoelectric element 23. Then, the control unit 11 can estimate the ejection state of the ink droplets 4 that has changed due to the aging deterioration of the piezoelectric element 23 based on an evaluation value of the vibration signal detected by the detection unit 14. Here, as the predetermined test signal, a signal for operating the piezoelectric element 23 so as to eject the ink droplets 4 from the ejection hole 21 may be used, or a signal for operating the piezoelectric element 23 so as not to eject the ink droplets 4 from the ejection hole 21 may be used. In addition, the evaluation value of the vibration signal detected by the detection unit 14 is an index for evaluating the waveform of the vibration signal, and may be, for example, the maximum amplitude or period in the waveform of the vibration signal. In this embodiment, an example in which the maximum amplitude in the waveform of the vibration signal detected by the detection unit 14 is used as the evaluation value will be described. In the following, the maximum amplitude in the waveform of the vibration signal detected by the detection unit 14 may be simply referred to as the "amplitude of the vibration signal."

[0031] Fig. 5 shows the waveform of the vibration signal (voltage) detected by the detection unit 14. The solid line in Fig. 5 shows the waveform of the vibration signal detected by the detection unit 14 at a first timing, which is indicated as "initial signal" in the figure. The first timing may be understood as the timing when the ejection head 5 is used for the first time after maintenance of the ejection head 5 (after replacement, as an example). The dashed line in Fig. 5 shows the waveform of the vibration signal detected by the detection unit 14 at a second timing when time has passed since the first timing and the piezoelectric element 23 has deteriorated over time, which is indicated as "detection signal" in the figure.

[0032] At the second timing when the deterioration of the piezoelectric element 23 has progressed, even if the same predetermined inspection signal (e.g., voltage) as at the first timing is applied to the piezoelectric element 23, the amount of displacement generated by the piezoelectric element 23 decreases, and the pressure applied to the liquid chamber 22 also decreases. As a result, the residual vibration in the liquid chamber 22 also decreases, and as shown in Fig. 5, the amplitude (detected amplitude) of the vibration signal detected by the detection unit 14 at the second timing becomes smaller than the amplitude (initial amplitude) of the vibration signal detected by the detection unit 14 at the first timing. In other words, the more the deterioration of the piezoelectric element 23 progresses over time, the smaller the amplitude of the vibration signal detected by the detection unit 14 becomes.

[0033] Furthermore, when the pressure that the piezoelectric element 23 applies to the liquid chamber 22 decreases due to deterioration of the piezoelectric element 23 over time, the ejection state of the ink droplet 4 ejected from the ejection hole 21 may change accordingly. Specifically, as deterioration of the piezoelectric element 23 over time progresses, the ejection speed and ejection volume of the ink droplet 4 ejected from the ejection hole 21 may decrease accordingly. In other words, there is a correlation between the amplitude (evaluation value) of the vibration signal detected by the detection unit 14 and the ejection state of the ink droplet 4. Therefore, the ejection state of the ink droplet 4 ejected from the ejection hole 21 can be estimated based on the amplitude of the vibration signal detected by the detection unit 14. In the following, the ejection speed of the ink droplet 4 will be described as an example of the ejection state of the ink droplet 4.

[0034] FIG. 6(a) shows the discharge velocity of the ink droplet 4 measured by the droplet measuring unit 15 at regular intervals for a certain period in one discharge unit 20 out of the multiple discharge units 20, i.e., the change over time in the discharge velocity of the ink droplet 4 measured by the droplet measuring unit 15. FIG. 6(b) shows the amplitude of the vibration signal detected by the detection unit 14 at regular intervals for a certain period in the one discharge unit 20, i.e., the change over time in the amplitude of the vibration signal detected by the detection unit 14. FIG. 6(c) shows the discharge velocity of the ink droplet 4 measured by the droplet measuring unit 15 at the one discharge unit 20 on the vertical axis and the amplitude of the vibration signal detected by the detection unit 14 on the horizontal axis. As shown in FIG. 6(c), it can be seen that a correlation can be obtained between the amplitude of the vibration signal and the discharge velocity of the ink droplet 4.

[0035] Since it takes a considerable amount of time for the droplet measuring unit 15 to measure the ejection state (e.g., the ejection speed) of the piezoelectric element 23, it may be disadvantageous in terms of the throughput of the liquid ejection device 1 to have the droplet measuring unit 15 sequentially measure the ejection state that has changed due to deterioration over time of the piezoelectric element 23. Therefore, by generating in advance information showing the correlation between the amplitude of the vibration signal and the ejection speed of the ink droplet 4 as shown in Fig. 6(c), the ejection state of the ink droplet 4 can be estimated from the detection result of the detection unit 14 using this information. By estimating the ejection state of the ink droplet 4 in this way, the drive signal provided to the piezoelectric element 23 can be corrected based on the estimation result so that the ejection state of the ink droplet 4 becomes a desired state.

[0036] Conventionally, information indicating the correlation between the amplitude of the vibration signal and the ejection speed of the ink droplets 4 is generated individually for each of the multiple ejection sections 20. However, in order to generate the information individually for one ejection section 20, it is necessary to obtain a set of the amplitude of the vibration signal and the ejection state of the ink droplets 4 at least twice at a time interval that allows the piezoelectric element 23 of that one ejection section 20 to deteriorate over time to a certain extent. In this case, the drive signal cannot be corrected until the piezoelectric element 23 of that one ejection section 20 deteriorates over time to a certain extent and the information can be generated, making it difficult to accurately control the multiple ejection sections 20.

[0037] As a result of intensive research, the inventors of the present application have found that the vibration signals (amplitudes) detected by the detection unit 14 are different from one another in the multiple ejection units 20, and that the ejection states of the ink droplets 4 are different from one another depending on the differences in the vibration signals. The inventors have also found that the "information indicating the correlation between the vibration signal and the ejection state" generated from the differences between the multiple ejection units regarding the pairs of the vibration signal and the ejection state indicates the tendency of the change in the ejection state with respect to the change in the vibration signal due to deterioration over time for each ejection unit 20. This means that if the pairs of the vibration signal and the ejection state are first acquired for each of the multiple ejection units 20, it is possible to generate the "information indicating the correlation between the vibration signal and the ejection state" without waiting for the piezoelectric element 23 of each ejection unit 20 to deteriorate over time. Then, by commonly using the "information indicating the correlation between the vibration signal and the ejection state" generated in this way for the multiple ejection units 20, it becomes possible to estimate the ejection state of the ink droplets 4 for each ejection unit 20 from the detection result at the detection unit 14. In the following, "information indicating the correlation between the vibration signal and the ejection state" generated from the differences between a plurality of ejection sections regarding the pairs of the vibration signal and the ejection state may be referred to as "correlation information".

[0038] FIG. 7(a) shows "a set of the amplitude of the vibration signal and the ejection speed of the ink droplet 4" acquired by each of the ejection parts A to E selected from the multiple ejection parts 20. In FIG. 7(a), the amplitude of the vibration signal is plotted on the horizontal axis, and the ejection speed of the ink droplet 4 is plotted on the vertical axis. Here, the "set of the amplitude of the vibration signal and the ejection speed of the ink droplet 4" is data indicating a set of the amplitude of the vibration signal detected by the detection part 14 and the ejection speed of the ink droplet 4 measured by the droplet measurement part 15, and may be referred to as "set data" below. Also, at least one set of set data in FIG. 7(a) is acquired for each of the ejection parts A to E. For example, the set data may be obtained by a single detection / measurement performed for the first time for each ejection part 20 after maintenance of the ejection head 5 (after replacement, for example). Alternatively, the set data may be a representative value (for example, an average value, a median value) of a plurality of detection / measurements in order to reduce the variation in the detection / measurement.

[0039] As shown in FIG. 7(a), the amplitudes of the vibration signals detected by the detection unit 14 are different from each other in the multiple ejection units 20 (ejection units A to E), and the ejection speeds of the ink droplets 4 are different from each other according to the difference in the amplitudes. Therefore, correlation information can be generated from the differences between the multiple ejection units regarding the group data. The correlation information may be generated as a calculation formula (function) for calculating the ejection speed of the ink droplets 4 from the amplitude of the vibration signal, or may be generated as a table showing the relationship between the amplitude of the vibration signal and the ejection speed of the ink droplets 4. As an example, the correlation information may be generated as a function of an approximation line 30 (for example, an approximation straight line) obtained for the multiple group data obtained by each of the ejection units A to E, as shown by the dashed line in FIG. 7(a). The correlation information generated in this manner is used in common by the multiple ejection units 20 to estimate the ejection speed of the ink droplets 4 from the detection result of the detection unit 14 for each ejection unit 20.

[0040] FIG. 7(b) shows a plot of the amplitude of the vibration signal detected by the detection unit 14 at regular intervals for a certain period of time and the ejection speed of the ink droplet 4 measured by the droplet measurement unit 15 for each of the ejection units A to E. In FIG. 7(b), the approximation line 30 generated as the correlation information as described above is shown. As shown in FIG. 7(b), it can be seen that the "change tendency of the ejection speed with respect to the amplitude of the vibration signal" due to deterioration over time for each of the ejection units A to E follows the "change tendency of the ejection speed with respect to the amplitude of the vibration signal" in the correlation information (approximation line 30). This means that it can be assumed that the "change tendency of the ejection speed with respect to the amplitude of the vibration signal" due to deterioration over time for each of the ejection units 20 follows the "change tendency of the ejection speed with respect to the amplitude of the vibration signal" in the correlation information. Therefore, in this embodiment, under such an assumption, the correlation information is commonly used for the multiple ejection units 20, and the ejection speed of the ink droplet 4 that has changed due to deterioration over time is estimated for each of the ejection units 20 from the detection result of the detection unit 14. Here, in the above, the ejection speed has been exemplified as an ejection state of the ink droplets 4, but the same applies to the ejection volume.

[0041] Fig. 8 is a flowchart showing an example of control of the multiple ejection units 20 in the ejection head 5. Each step of the flowchart in Fig. 8 can be executed by the control unit 11. Note that the flowchart in Fig. 8 may be understood as a flowchart showing a method of controlling the liquid ejection device 1.

[0042] In step S201, the control unit 11 determines whether correlation information commonly used by a plurality of ejection units 20 has already been generated for the currently used ejection head 5. If correlation information has already been generated, the process proceeds to step S203, and if correlation information has not yet been generated, the process proceeds to step S202.

[0043] In step S202, the control unit 11 generates correlation information for the ejection head 5 currently being used. Specifically, as described above, the control unit 11 acquires group data indicating a pair of the amplitude of the vibration signal and the ejection state (ejection speed, ejection volume) of the ink droplet 4 for each ejection unit 20. Then, the control unit 11 generates correlation information from the difference between the plurality of ejection units regarding the group data, using the plurality of group data acquired for each of the plurality of ejection units 20. The generation of correlation information can be performed in advance, for example, when the liquid ejection device 1 starts operating or when the operation is resumed after the completion of maintenance. Here, the amplitude of the vibration signal is acquired based on the detection result of the detection unit 14 when a predetermined inspection signal is applied to the piezoelectric element 23. In addition, the ejection state of the ink droplet 4 can be acquired based on the measurement result of the droplet measurement unit 15, but may also be acquired by an external device that measures the ejection state of the ink droplet 4.

[0044] In step S203, the control unit 11 judges whether it is time to detect a vibration signal by the detection unit 14 (detection timing). This judgment can be determined, for example, based on the cumulative time for which the piezoelectric element 23 of each ejection unit 20 has been driven. As described above, the longer the cumulative time for which the piezoelectric element 23 is driven by a predetermined drive signal (for example, an applied voltage), the more its displacement decreases due to deterioration over time. Therefore, it is desirable that the detection of the vibration signal by the detection unit 14 is repeatedly performed at regular intervals, and further at a timing after the liquid ejection device 1 has performed the same action, for example, at a timing for each scan operation of the substrate stage 3. In this embodiment, the control unit 11 judges that it is the detection timing when the elapsed time since the previous detection of the vibration signal by the detection unit 14 is equal to or greater than a threshold value.

[0045] In step S204, the control unit 11 detects the vibration signal by the detection unit 14. Specifically, the control unit 11 provides a predetermined test signal to the piezoelectric element 23 for each ejection unit 20 to operate the piezoelectric element 23, and causes the detection unit 14 to detect a vibration signal representing the vibration in the liquid chamber 22 caused by the operation. The control unit 11 then stores in memory the vibration signal detected by the detection unit 14 for each ejection unit 20. At this time, the control unit 11 may also determine the amplitude (e.g., maximum amplitude) of the waveform of the vibration signal detected by the detection unit 14 for each ejection unit 20, and store the determined amplitude in memory.

[0046] In step S205, the control unit 11 determines whether or not to correct the drive signal provided to the piezoelectric element 23 to eject the ink droplet 4 from the ejection hole 21 for each ejection unit 20, based on the amplitude of the vibration signal detected in step S204. For example, the control unit 11 determines whether or not the difference between the amplitude of the vibration signal detected in step S204 and the amplitude of the vibration signal detected previously is equal to or greater than a specified value. If the difference is equal to or greater than the specified value, it determines that the drive signal is to be corrected, and proceeds to step S206. On the other hand, if the difference is less than the specified value, it determines that the drive signal is not to be corrected, and returns to step S203. Here, in this step S205, the control unit 11 may determine whether or not to correct the drive signal, based on a preset setting, such as once a day.

[0047] In step S206, the control unit 11 estimates the ejection state (ejection speed, ejection volume) of the ink droplet 4 for each ejection unit 20 based on the amplitude of the vibration signal detected in step S24. Specifically, the control unit 11 estimates the ejection state (ejection speed, ejection volume) converted from the amplitude of the vibration signal detected in step S204 based on correlation information for each ejection unit 20 as the ejection state of the ink droplet 4 changed due to the deterioration over time of the piezoelectric element 23. Explaining with reference to FIG. 7(a), the control unit 11 can estimate the ejection speed Vt from the amplitude At of the vibration signal detected by the detection unit 14 based on the correlation information (function of the approximation line 30). Such an estimation of the ejection speed is performed for each ejection unit 20 by using the correlation information (function of the approximation line 30) in common for the multiple ejection units 20. In addition, the control unit 11 stores the result of estimating the ejection state for each ejection unit 20 in a memory.

[0048] In step S207, the control unit 11 corrects the drive signal given to the piezoelectric element 23 for each ejection unit 20. Specifically, the control unit 11 corrects the drive signal for each ejection unit 20 based on the estimation result of the ejection state of the ink droplet 4 obtained in step S206 so that the ejection state of the ink droplet 4 from the ejection hole 21 becomes a desired ejection state (target ejection speed, target ejection volume). When correcting the ejection speed of the ink droplet 4, the control unit 11 can correct the ejection timing of the ink droplet 4 so that the ink droplet 4 adheres to the target position on the substrate 2 according to the difference between the ejection speed of the ink droplet 4 estimated in step S206 and the target ejection speed. The correction of the ejection timing of the ink droplet 4 may be understood as correcting the timing of giving the drive signal (e.g., pulse signal) to the piezoelectric element 23. Furthermore, when correcting the ejection volume of the ink droplets 4, the control unit 11 may correct the waveform of the drive signal (e.g., the amplitude of the pulse signal) provided to the piezoelectric element 23 so as to reduce the difference between the ejection volume of the ink droplets 4 estimated in step S206 and the target ejection volume. Alternatively, the control unit 11 may correct (change) the combination of ejection units 20 used to eject the ink droplets 4 onto the substrate 2 based on the ejection volume of the ink droplets 4 estimated for each ejection unit 20 so that the total amount of ink ejected onto the substrate 2 becomes the target amount.

[0049] In step S208, the control unit 11 determines whether or not the liquid ejection device 1 is stopped for maintenance or the like. Maintenance of the liquid ejection device 1 may include replacement of the ejection head 5. If the liquid ejection device 1 is not stopped, the process returns to step S203, and steps S203 to S208 are repeatedly executed. On the other hand, if the liquid ejection device 1 is stopped, the process ends. In this case, when the liquid ejection device 1 is restarted, the flowchart in FIG. 8 may start again from step S201.

[0050] As described above, the liquid ejection device 1 of the present embodiment generates correlation information indicating the correlation between the vibration signal and the ejection state of the ink droplets 4 in advance from the differences between the multiple ejection units regarding the pair of the vibration signal (amplitude) and the ejection state of the ink droplets 4. Then, the correlation information is used in common by the multiple ejection units 20, and the ejection state of the ink droplets 4 that has changed due to deterioration over time of the piezoelectric element 23 is estimated for each ejection unit 20 from the detection result of the detection unit 14. This makes it possible to reduce the time required to generate the correlation information compared to the conventional method in which correlation information is generated for each ejection unit 20, and therefore makes it possible to accurately control the multiple ejection units 20 using the correlation information.

[0051] Here, in the present embodiment, an example has been described in which the correlation information commonly used by the multiple ejection units 20 is generated by the control unit 11 of the liquid ejection device 1, but it may also be generated by an information processing device provided outside the liquid ejection device 1. That is, step S202 in the flowchart of Fig. 8 may be performed by an information processing device external to the liquid ejection device 1. In this case, the external information processing device generates the correlation information by acquiring "pairs of vibration signals and ejection states of ink droplets 4" for each ejection unit 20, and the liquid ejection device 1 may acquire the correlation information generated by the external information processing device from the information processing device.

[0052] <Embodiment of the article manufacturing method> The article manufacturing method according to the embodiment of the present invention is suitable for manufacturing articles such as display panels for organic EL displays, microdevices such as semiconductor devices, and elements having fine structures. The article manufacturing method according to the present embodiment includes a discharge step of discharging (supplying) liquid onto a substrate using the above-mentioned liquid supply device (liquid supply method), a processing step of processing the substrate to which the liquid has been supplied in the discharge step, and a step of manufacturing an article from the substrate processed in the processing step. Furthermore, the article manufacturing method includes other well-known steps (firing, cooling, cleaning, oxidation, film formation, deposition, doping, flattening, etching, resist stripping, dicing, bonding, packaging, etc.). The article manufacturing method according to the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article compared to conventional methods.

[0053] <Other embodiments> The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0054] <Summary of the embodiment> The disclosure of this specification includes at least the following liquid ejection device, article manufacturing method, control method, information processing device, generation method, and program. (Item 1) a plurality of ejection units each including a liquid chamber having an ejection hole and a piezoelectric element for applying pressure to the liquid chamber to eject droplets from the ejection hole; a detection unit that detects a signal representing vibration in the liquid chamber caused by actuation of the piezoelectric element for each of the plurality of ejection units; A control unit that controls each of the plurality of ejection units; Equipped with In the plurality of ejection sections, the signals detected by the detection section are different from one another, and ejection states of droplets from the ejection holes are different from one another in response to the difference in the signals, The control unit is generating correlation information indicating a correlation between the signal and the ejection state in advance from a difference between the plurality of ejection sections regarding a pair of the signal and the ejection state; using the correlation information in common to the plurality of ejection units, and estimating the ejection state that has changed due to deterioration over time for each ejection unit from the detection result of the detection unit; controlling each of the plurality of ejection units based on the result of the ejection state estimation; A liquid ejection device comprising: (Item 2) The liquid ejection device described in item 1, characterized in that the control unit estimates the ejection state converted from the signal detected by the detection unit based on the correlation information as the ejection state that has changed due to deterioration over time for each ejection unit. (Item 3) The liquid ejection device described in item 2, characterized in that the control unit estimates the ejection state that has changed due to deterioration over time for each ejection unit by assuming that the change trend of the ejection state for the signal due to deterioration over time of each ejection unit follows the change trend of the ejection state for the signal in the correlation information. (Item 4) 4. The liquid ejection device according to any one of items 1 to 3, wherein the control unit generates the correlation information based on at least one of the sets obtained for each ejection unit. (Item 5) The liquid ejection device described in any one of items 1 to 4, characterized in that the detection unit detects the signal when the piezoelectric element is operated to eject droplets from the ejection hole for each of the multiple ejection units. (Item 6) The liquid ejection device described in any one of items 1 to 5, characterized in that the detection unit detects the signal when the piezoelectric element is activated so as not to eject droplets from the ejection hole for each of the multiple ejection units. (Item 7) a measuring unit that measures the ejection state of each of the plurality of ejection units, the control unit generates the correlation information by acquiring, for each ejection unit, a pair of the signal detected by the detection unit and the ejection state measured by the measurement unit. 7. The liquid ejection device according to any one of items 1 to 6, (Item 8) The liquid ejection device described in any one of items 1 to 6, characterized in that the control unit generates the correlation information by acquiring, for each ejection unit, a pair of the signal detected by the detection unit and the ejection state measured by an external device. (Item 9) 9. The liquid ejection device according to any one of items 1 to 8, wherein the ejection state includes at least one of a speed and a volume of the liquid droplets ejected from the ejection hole. (Item 10) 10. The liquid ejection device according to any one of items 1 to 9, wherein the plurality of ejection sections are configured as one structure. (Item 11) A discharge step of discharging a liquid onto a substrate using the liquid discharge device according to any one of items 1 to 10; a processing step of processing the substrate onto which the liquid has been discharged in the discharging step; a manufacturing process for manufacturing an article from the substrate processed in the processing process; A method for manufacturing an article, comprising: (Item 12) A method for controlling a liquid ejection device having a plurality of ejection units, each of which has a liquid chamber having an ejection hole and a piezoelectric element that applies pressure to the liquid chamber to eject liquid droplets from the ejection hole, comprising the steps of: In the plurality of ejection sections, signals representing vibrations in the liquid chambers caused by actuation of the piezoelectric elements are different from one another, and ejection states of droplets from the ejection holes are different from one another in accordance with the differences in the signals. The control method includes: an acquisition step of acquiring a pair of the signal and the ejection state for each ejection unit; a generating step of generating correlation information indicating a correlation between the signal and the ejection state from differences among the plurality of ejection units regarding the sets, using the sets acquired for each ejection unit in the acquiring step; an estimation step of estimating the ejection state that has changed due to deterioration over time for each ejection part from the detection result of the signal by using the correlation information in common to the plurality of ejection parts; a control step of controlling the plurality of ejection units based on an estimation result in the estimation step; A control method comprising: (Item 13) 1. An information processing device for generating information used in a liquid ejection device including a plurality of ejection units each having a liquid chamber having an ejection hole and a piezoelectric element that applies pressure to the liquid chamber to eject liquid droplets from the ejection hole, In the plurality of ejection sections, signals representing vibrations in the liquid chambers caused by actuation of the piezoelectric elements are different from one another, and ejection states of droplets from the ejection holes are different from one another in accordance with the differences in the signals. The information processing device includes: A pair of the signal and the ejection state is acquired for each ejection unit; generating correlation information indicating a correlation between the signal and the ejection state from differences among the plurality of ejection units regarding the sets using the sets obtained for each ejection unit; The correlation information is information commonly used by the plurality of ejection units in order to estimate the ejection state that has changed due to deterioration over time for each ejection unit from the detection result of the signal. 23. An information processing apparatus comprising: (Item 14) A method for generating information used in a liquid ejection device having a plurality of ejection units, each of which has a liquid chamber having an ejection hole and a piezoelectric element that applies pressure to the liquid chamber to eject liquid droplets from the ejection hole, by using an information processing device, comprising: In the plurality of ejection sections, signals representing vibrations in the liquid chambers caused by actuation of the piezoelectric elements are different from one another, and ejection states of droplets from the ejection holes are different from one another in accordance with the differences in the signals. The method for producing the same comprises: an acquisition step of acquiring a pair of the signal and the ejection state for each ejection unit; a generating step of generating correlation information indicating a correlation between the signal and the ejection state from differences between the plurality of ejection units regarding the sets, using the sets acquired for each ejection unit in the acquiring step, The correlation information is information commonly used by the plurality of ejection units in order to estimate the ejection state that has changed due to deterioration over time for each ejection unit from the detection result of the signal. A generating method comprising: (Item 15) Item 15. A program for causing a computer to execute the generating method according to item 14.

[0055] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0056] 1: liquid supply device, 2: substrate, 3: substrate stage, 4: ink droplets, 5: ejection head, 11: control unit, 14: detection unit, 15: droplet measurement unit, 20: ejection unit, 21: ejection hole, 22: liquid chamber, 23: piezoelectric element

Claims

1. a plurality of ejection units each including a liquid chamber having an ejection hole and a piezoelectric element for applying pressure to the liquid chamber to eject droplets from the ejection hole; a detection unit that detects a signal representing vibration in the liquid chamber caused by actuation of the piezoelectric element for each of the plurality of ejection units; A control unit that controls each of the plurality of ejection units; Equipped with In the plurality of ejection sections, the signals detected by the detection section are different from one another, and ejection states of droplets from the ejection holes are different from one another in response to the difference in the signals, The control unit is generating correlation information indicating a correlation between the signal and the ejection state in advance from a difference between the plurality of ejection sections regarding a pair of the signal and the ejection state; using the correlation information in common to the plurality of ejection units, and estimating the ejection state that has changed due to deterioration over time for each ejection unit from the detection result of the detection unit; controlling each of the plurality of ejection units based on the result of the ejection state estimation; A liquid ejection device comprising:

2. The liquid ejection device according to claim 1 , wherein the control unit estimates, for each ejection unit, the ejection state converted based on the correlation information from the signal detected by the detection unit as the ejection state that has changed due to deterioration over time.

3. The liquid ejection device described in claim 2, characterized in that the control unit estimates the ejection state that has changed due to deterioration over time for each ejection unit by assuming that the trend of change in the ejection state for the signal due to deterioration over time of each ejection unit follows the trend of change in the ejection state for the signal in the correlation information.

4. The liquid ejection device according to claim 1 , wherein the control unit generates the correlation information based on at least one of the sets obtained for each ejection unit.

5. 2. The liquid ejection device according to claim 1, wherein the detection section detects the signal when the piezoelectric element is actuated so as to eject liquid droplets from the ejection hole for each of the plurality of ejection sections.

6. 2. The liquid ejection device according to claim 1, wherein the detection section detects the signal when the piezoelectric element is operated so as not to eject droplets from the ejection hole for each of the plurality of ejection sections.

7. a measuring unit that measures the ejection state of each of the plurality of ejection units, the control unit generates the correlation information by acquiring, for each ejection unit, a pair of the signal detected by the detection unit and the ejection state measured by the measurement unit. The liquid ejection device according to claim 1 .

8. The liquid ejection device according to claim 1 , wherein the control unit generates the correlation information by acquiring, for each ejection unit, a pair of the signal detected by the detection unit and the ejection state measured by an external device.

9. The liquid ejection device according to claim 1 , wherein the ejection state includes at least one of a speed and a volume of the liquid droplets ejected from the ejection hole.

10. The liquid ejection device according to claim 1 , wherein the plurality of ejection sections are configured as a single structure.

11. A discharge step of discharging liquid onto a substrate using the liquid discharge device according to claim 1 ; a processing step of processing the substrate onto which the liquid has been discharged in the discharging step; a manufacturing process for manufacturing an article from the substrate processed in the processing process; A method for manufacturing an article, comprising:

12. A method for controlling a liquid ejection device having a plurality of ejection units, each of which has a liquid chamber having an ejection hole and a piezoelectric element that applies pressure to the liquid chamber to eject liquid droplets from the ejection hole, comprising the steps of: In the plurality of ejection sections, signals representing vibrations in the liquid chambers caused by actuation of the piezoelectric elements are different from one another, and ejection states of droplets from the ejection holes are different from one another in accordance with the differences in the signals. The control method includes: an acquisition step of acquiring a pair of the signal and the ejection state for each ejection unit; a generating step of generating correlation information indicating a correlation between the signal and the ejection state from differences among the plurality of ejection units regarding the sets, using the sets acquired for each ejection unit in the acquiring step; an estimation step of estimating the ejection state that has changed due to deterioration over time for each ejection part from the detection result of the signal by using the correlation information in common to the plurality of ejection parts; a control step of controlling the plurality of ejection units based on an estimation result in the estimation step; A control method comprising:

13. 1. An information processing device for generating information used in a liquid ejection device including a plurality of ejection units each having a liquid chamber having an ejection hole and a piezoelectric element that applies pressure to the liquid chamber to eject liquid droplets from the ejection hole, In the plurality of ejection sections, signals representing vibrations in the liquid chambers caused by actuation of the piezoelectric elements are different from one another, and ejection states of droplets from the ejection holes are different from one another in accordance with the differences in the signals. The information processing device includes: A pair of the signal and the ejection state is acquired for each ejection unit; generating correlation information indicating a correlation between the signal and the ejection state from differences among the plurality of ejection units regarding the sets using the sets obtained for each ejection unit; The correlation information is information commonly used by the plurality of ejection units in order to estimate the ejection state that has changed due to deterioration over time for each ejection unit from the detection result of the signal.

23. An information processing apparatus comprising:

14. A method for generating information used in a liquid ejection device having a plurality of ejection units, each of which has a liquid chamber having an ejection hole and a piezoelectric element that applies pressure to the liquid chamber to eject liquid droplets from the ejection hole, by using an information processing device, comprising: In the plurality of ejection sections, signals representing vibrations in the liquid chambers caused by actuation of the piezoelectric elements are different from one another, and ejection states of droplets from the ejection holes are different from one another in accordance with the differences in the signals. The method for producing the same comprises: an acquisition step of acquiring a pair of the signal and the ejection state for each ejection unit; a generating step of generating correlation information indicating a correlation between the signal and the ejection state from differences among the plurality of ejection units regarding the sets, using the sets acquired for each ejection unit in the acquiring step, The correlation information is information commonly used by the plurality of ejection units in order to estimate the ejection state that has changed due to deterioration over time for each ejection unit from the detection result of the signal. A generating method comprising:

15. A program for causing a computer to execute the generating method according to claim 14.

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