Liquid ejection device, printing method, and liquid ejection program

Abstract

The goal is to shorten the cycle time. [Solution] The liquid discharge device of the embodiment comprises a liquid discharge head and a control unit. The liquid discharge head comprises a nozzle that communicates with a pressure chamber and discharges liquid droplets, a pressure chamber that communicates with the nozzle, and a piezoelectric element that changes the pressure inside the pressure chamber via a diaphragm that forms part of the wall of the pressure chamber. The control unit controls the liquid discharge head. The control unit applies a drive waveform 50 to the piezoelectric element that causes liquid droplets to be discharged from the nozzle two or more times in one cycle.

Description

Technical Field

[0001] Embodiments of the present invention relate to a liquid ejection device, a printing method, and a liquid ejection program.

Background Art

[0002] In the production of a production target having a fine structure such as an electronic device, an inkjet liquid ejection device is used (for example, see Patent Document 1). In such a liquid ejection device, by repeatedly scanning a head provided with nozzles in the scanning direction with respect to a discharge target substrate a plurality of times, the total discharge amount with respect to cells provided on the discharge target substrate is controlled to be a discharge amount that realizes a target film thickness.

[0003] However, in the prior art, an increase in the tact time of manufacturing the production target may be a problem.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention has been made in view of the above, and an object thereof is to provide a liquid ejection device, a printing method, and a liquid ejection program capable of shortening the tact time.

Means for Solving the Problems

[0006] The liquid dispensing device of the embodiment comprises a liquid dispensing head and a control unit. The liquid dispensing head comprises a nozzle that communicates with a pressure chamber and dispenses droplets, a pressure chamber that communicates with the nozzle, and a piezoelectric element that changes the pressure inside the pressure chamber via a diaphragm that forms part of the wall of the pressure chamber. The control unit controls the liquid dispensing head. The control unit applies a drive waveform to the piezoelectric element that causes droplets to be dispensed from the nozzle two or more times in one cycle. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is an explanatory diagram of the system according to the embodiment. [Figure 2] Figure 2 is a schematic diagram of an example of a liquid dispensing head. [Figure 3] Figure 3 is a schematic diagram of an example of a substrate to be extruded. [Figure 4] Figure 4 is an explanatory diagram of an example of a drive waveform in the embodiment. [Figure 5] Figure 5 is a flowchart showing an example of the information processing flow performed by the control unit of the liquid dispensing device in the embodiment. [Figure 6] Figure 6 is a schematic diagram of an example of a conventional drive waveform. [Figure 7A] Figure 7A is an explanatory diagram of the liquid film formed by applying a conventional drive waveform. [Figure 7B] Figure 7B is an explanatory diagram of the liquid film formed by the application of a conventional drive waveform. [Figure 7C] Figure 7C is an explanatory diagram of a liquid film formed by the application of a conventional drive waveform. [Figure 7D] Figure 7D is an explanatory diagram of a liquid film formed by the application of a conventional drive waveform. [Figure 8A] Figure 8A is an explanatory diagram of the liquid film formed by applying the drive waveform of the embodiment. [Figure 8B] Figure 8B is an explanatory diagram of the liquid film formed by applying the drive waveform of the embodiment. [Figure 9A] Figure 9A shows the evaluation results of the discharge speed. [Figure 9B]FIG. 9B is a diagram showing the evaluation results of the ejection speed. [Figure 9C] FIG. 9C is a diagram showing the evaluation results of the ejection speed. [Figure 9D] FIG. 9D is a diagram showing the evaluation results of the ejection speed. [Figure 10A] FIG. 10A is a diagram showing the evaluation results of the allowable range of the difference in ejection volume. [Figure 10B] FIG. 10B is a diagram showing the evaluation results of the allowable range of the difference in ejection speed. [Figure 10C] FIG. 10C is a diagram showing the evaluation results of the difference in droplet landing time. [Figure 11] FIG. 11 is a diagram showing the evaluation results of conventional ejection using a conventional drive waveform and embodiment ejection using the drive waveform of the embodiment. [Figure 12] FIG. 12 is a diagram showing the evaluation results of conventional ejection using a conventional drive waveform and embodiment ejection using the drive waveform of the embodiment. [Figure 13] FIG. 13 is a diagram showing the evaluation results of droplet landing by droplets ejected from a nozzle by applying a drive waveform. [Figure 14] FIG. 14 is a hardware configuration diagram.

MODE FOR CARRYING OUT THE INVENTION

[0008] Embodiments of a liquid ejection device, a printing method, and a liquid ejection program will be described in detail below with reference to the accompanying drawings.

[0009] FIG. 1 is an explanatory diagram of an example of the system 1 of the present embodiment.

[0010] The system 1 includes a liquid ejection device 10 and a stage 42. The drive units of the liquid ejection device 10 and the stage 42 are communicably connected.

[0011] The liquid ejection device 10 is an inkjet type liquid ejection device that ejects droplets 24 from a nozzle 23 onto a discharge target substrate 40.

[0012] The liquid dispensing device 10 comprises a control unit 21 and a liquid dispensing head 22. The control unit 21 and the liquid dispensing head 22 are communicated with each other.

[0013] The liquid ejection head 22 comprises one or more nozzles 23 for ejecting liquid droplets 24. Figure 1 shows one nozzle 23 for simplification. The liquid ejection head 22 is an inkjet type head that ejects liquid droplets 24 from the nozzles 23.

[0014] Figure 2 is a schematic diagram of an example of a liquid discharge head 22.

[0015] The liquid discharge head 22 comprises a nozzle 23, a pressure chamber 26, a diaphragm 27, and a piezoelectric element 28. The nozzle 23 communicates with the pressure chamber 26 and discharges liquid droplets 24. Liquid 29 is supplied to the pressure chamber 26 from a common channel (not shown) or the like. The diaphragm 27 forms part of the wall of the pressure chamber 26. The piezoelectric element 28 changes volume by voltage application control by a control unit 21 (described later). The pressure caused by the volume change of the piezoelectric element 28 is applied to the pressure chamber 26 via the diaphragm 27, causing the pressure chamber 26 to expand and contract in accordance with the volume change, and liquid droplets 24 of liquid 29 are discharged from the nozzle 23. The nozzle 23 and the piezoelectric element 28 that contributes to the discharge of liquid droplets 24 from the nozzle 23 are arranged in a one-to-one relationship. Therefore, the discharge of liquid droplets 24 by the nozzle 23 corresponding to the piezoelectric element 28 is controlled by voltage application control to the piezoelectric element 28. In the following, the nozzle 23 and the piezoelectric element 28 that contributes to the discharge of droplets 24 from the nozzle 23 may be described as the piezoelectric element 28 corresponding to the nozzle 23, the nozzle 23 corresponding to the piezoelectric element 28, and so on.

[0016] Returning to Figure 1, we continue the explanation.

[0017] The substrate 40 to be dispensed is the target of liquid droplets 24 dispensed by the liquid dispensing device 10.

[0018] The manufacturing target is produced by ejecting droplets 24 onto the target substrate 40. Examples of manufacturing targets include printed materials, electronic devices such as display panels, color filters, micro-LEDs (Light Emitting Diodes), battery separators, herovskite-type solar cells, semiconductor substrates, etc. The target substrate 40 and the liquid 29 can be pre-adjusted according to the manufacturing target.

[0019] The substrate 40 to be dispensed is placed on the stage 42. The stage 42 is configured to be scannable relative to the liquid dispensing head 22 in the scanning direction X by control of the control unit 21. For example, the control unit 21 controls the drive unit of the stage 42 to scan the stage 42 in the scanning direction X relative to the liquid dispensing head 22. Note that the substrate 40 to be dispensed and the stage 42 only need to be configured to be scannable relative to the scanning direction X. Therefore, the control unit 21 may scan the liquid dispensing head 22 in the scanning direction X by scanning the liquid dispensing head 22 in the scanning direction X relative to the substrate 40 on the stage 42.

[0020] In this embodiment, as an example, the stage 42 is scanned in the scanning direction X relative to the liquid discharge head 22 by the control of the control unit 21, which will be described later, so that the discharge target substrate 40 placed on the stage 42 is scanned in the scanning direction X relative to the liquid discharge head 22. In this embodiment, droplets 24 are discharged onto the discharge target substrate 40, which is being scanned at a constant speed in the scanning direction X.

[0021] Figure 3 is a schematic diagram of an example of a substrate 40 to be ejected.

[0022] Multiple cells S are provided on the substrate 40 to be extruded.

[0023] Cell S is the area on the substrate 40 to which the liquid droplets 24 are ejected. When the liquid droplets 24 are ejected into cell S, a liquid film is formed on cell S. The substrate 40 on which the liquid film of the liquid droplets 24 has been formed on cell S then undergoes various processes to function as a manufactured object such as a display panel.

[0024] The size, shape, and arrangement of cell S may be pre-adjusted according to the object to be manufactured and are not limited to the form shown in Figure 3. If the object to be manufactured has a fine structure such as a display panel, for example, the long side or diameter of cell S may be 20 μm to 40 μm in size. Preferably, an effective droplet area EA is pre-set in cell S. The effective droplet area EA is the area within cell S that allows droplets 24 to adhere. By discharging droplets 24 into the effective droplet area EA, splashing of droplets 24 to the outside of cell S or to other cells S is suppressed. The range of the effective droplet area EA in cell S may be calculated by a known method and pre-set.

[0025] Returning to Figure 1, we continue the explanation.

[0026] The control unit 21 controls the scanning of the liquid discharge head 22 and the stage 42 in the scanning direction X, etc.

[0027] The control unit 21 is implemented by one or more processors. For example, the control unit 21 may be implemented by having a processor such as a CPU (Central Processing Unit) execute a program, i.e., by software.

[0028] The control unit 21 may be implemented by a dedicated IC (Integrated Circuit) or other processor, i.e., hardware. The control unit 21 may also be implemented using a combination of software and hardware. When multiple processors are used, each processor may implement one of the parts, or two or more of the parts. Furthermore, at least one of the one or more functional parts included in the control unit 21 may be mounted on an external information processing device that is communicably connected to the liquid dispensing device 10 via a network or the like.

[0029] The control unit 21 applies a drive waveform to the piezoelectric element 28 based on the print data. When a voltage represented by the drive waveform is applied, the piezoelectric element 28 undergoes a volume change in accordance with the drive waveform, and the pressure caused by the volume change of the piezoelectric element 28 is applied to the pressure chamber 26 via the diaphragm 27. As pressure corresponding to the drive waveform is applied to the pressure chamber 26, the pressure chamber 26 expands and contracts, and droplets 24 of liquid 29 are discharged from the nozzle 23 connected to the pressure chamber 26.

[0030] The print data consists of specified data for each of the multiple nozzles 23 provided on the liquid ejection head 22, such as whether or not ejection occurs, the amount ejected, and the ejection position. The data format of the print data can be any known format usable with an inkjet liquid ejection device 10.

[0031] The control unit 21 generates a drive waveform to be applied to each of the piezoelectric elements 28 corresponding to the multiple nozzles 23 provided on the liquid ejection head 22, according to the print data. The control unit 21 then scans the stage 42 and applies the drive waveform to the piezoelectric elements 28 so that droplets 24 are ejected from the nozzles 23 to each cell S of the ejection target substrate 40, which is being scanned at a constant speed in the scanning direction X.

[0032] The drive waveform is a waveform that represents the change in voltage (potential) applied to the piezoelectric element 28 over one cycle. In other words, the drive waveform is a waveform that represents the change in voltage (potential) required to eject droplets 24 from the nozzle 23 over one cycle.

[0033] One period, which is the unit of the drive waveform, is the unit of repetition of the repeating wave element. In this embodiment, one example is described in which one period is the period of movement in the scanning direction X during which a droplet 24 can be ejected from one cell S on the substrate 40 by one nozzle 23. In other words, in this embodiment, one period is the period during which a droplet 24 can be ejected from one cell S on the substrate 40 by one nozzle 23 provided on the liquid ejection head 22 when the liquid ejection head 22 is scanned relative to the substrate 40 in the scanning direction X. In other words, in this embodiment, one example is described in which one period is the period during which one nozzle 23 passes over the droplet effective area EA of one cell S on the substrate 40 in the scanning direction X.

[0034] The drive waveform of this embodiment is a waveform that causes droplets 24 to be ejected from the nozzle 23 two or more times in one cycle.

[0035] Therefore, in this embodiment, two or more droplets 24 are ejected from the nozzle 23 corresponding to the piezoelectric element 28 to which the drive waveform is applied, with a single application of the drive waveform. Specifically, for example, in this embodiment, two or more droplets 24 are ejected from the nozzle 23 corresponding to the piezoelectric element 28 to which the drive waveform is applied, to one cell S during a single scan in the scanning direction X.

[0036] The control unit 21 should calculate a number of droplets 24 to be ejected in one cycle, which should be two or more, according to the print data, the characteristics of the liquid 29 to be ejected, the size of the cell S, the target film thickness, etc. Then, the control unit 21 should generate a drive waveform that ejects the calculated number of droplets 24 (two or more) from the nozzle 23 in one cycle, and apply it to the piezoelectric element 28.

[0037] Figure 4 is an explanatory diagram of an example of the drive waveform 50 in this embodiment.

[0038] In Figure 4, the horizontal axis represents time, and the vertical axis represents voltage. Figure 4 shows an example of a drive waveform 50 that ejects two droplets 24 from the nozzle 23 in one cycle.

[0039] The drive waveform 50 has, in this order, a reference maintenance element P1, a preliminary expansion element P2, a preliminary expansion maintenance element P3, a preliminary contraction element P4, a preliminary maintenance element P5, an expansion element P6, an expansion maintenance element P7, a contraction element P8, a contraction maintenance element P9, an expansion element P10, an expansion maintenance element P11, a contraction element P12, a contraction maintenance element P13, an expansion element P14, and a reference maintenance element P15.

[0040] The reference maintenance element P1 is a waveform element that maintains the application of the reference voltage Vbs. The reference voltage Vbs is the applied voltage to maintain the pressure chamber 26 at a reference volume. The pre-expansion element P2 is a waveform element that expands the volume of the pressure chamber 26 from its reference volume by decreasing the voltage from the state where the reference voltage Vbs is applied toward a second voltage V2 which is less than the reference voltage Vbs. The pre-expansion maintenance element P3 is a waveform element that maintains the application of the second voltage V2 for a predetermined time. The pre-contraction element P4 is a waveform element that contracts the volume of the pressure chamber 26 to its reference volume by increasing the voltage from the state where the second voltage V2 is applied toward the reference voltage Vbs. The pre-maintenance element P5 is a waveform element that maintains the application of the reference voltage Vbs.

[0041] The expansion element P6 is a waveform element that expands the volume of the pressure chamber 26 from its reference volume by decreasing the voltage from a state where a reference voltage Vbs is applied to a first voltage V1 which is less than the second voltage V2. The expansion element P6 draws the meniscus of the liquid 29 formed in the nozzle 23 into the pressure chamber 26, and liquid 29 is supplied into the pressure chamber 26 from a common flow path (not shown in the figure).

[0042] The expansion maintenance element P7 is a waveform element that maintains the volume of the pressure chamber 26, which has been expanded by the expansion element P6, in an expanded state for a certain period of time.

[0043] The contraction element P8 is a waveform element that contracts the volume inside the pressure chamber 26 by increasing the voltage from the state where the first voltage V1 is applied to the third voltage V3 which is higher than the reference voltage Vbs. The volume inside the pressure chamber 26 is rapidly contracted by the contraction element P8, the liquid 29 inside the pressure chamber 26 is pressurized, and the first droplet 24 is discharged from the nozzle 23 at timing t1, which is the end of the contraction element P8. Hereafter, the first droplet 24 discharged by the application of the drive waveform 50 for one cycle may be referred to as droplet 24a. Droplet 24a is an example of droplet 24.

[0044] The contraction maintenance element P9 is a waveform element that maintains the volume of the pressure chamber 26, which has been contracted by the contraction element P8, for a certain period of time.

[0045] The expansion element P10 is a waveform element that expands the volume of the pressure chamber 26 to the reference volume by decreasing the voltage from the state where the third voltage V3 is applied toward the reference voltage Vbs. The expansion element P10 draws the meniscus of the liquid 29 formed in the nozzle 23 toward the pressure chamber 26, and liquid 29 is supplied into the pressure chamber 26 from a common flow path (not shown in the figure).

[0046] The expansion maintenance element P11 is a waveform element that maintains the volume of the pressure chamber 26, which has been expanded by the expansion element P10, at a reference volume for a certain period of time.

[0047] The contraction element P12 is a waveform element that contracts the volume inside the pressure chamber 26 by increasing the voltage from the state where the reference voltage Vbs is applied toward the third voltage V3. The volume inside the pressure chamber 26 is rapidly contracted by the contraction element P12, the liquid 29 inside the pressure chamber 26 is pressurized, and at timing t2, which is the end of the contraction element P12, the second droplet 24 is discharged from the nozzle 23. Hereafter, the second droplet 24 discharged by the application of the drive waveform 50 for one cycle may be referred to as droplet 24b. Droplet 24b is an example of droplet 24.

[0048] The contraction maintenance element P13 is a waveform element that maintains the volume of the pressure chamber 26, which has been contracted by the contraction element P12, for a certain period of time.

[0049] The expansion element P14 is a waveform element that expands the volume of the pressure chamber 26 to the reference volume by decreasing the voltage from the state where the third voltage V3 is applied toward the reference voltage Vbs. The expansion element P14 draws the meniscus of the liquid 29 formed in the nozzle 23 toward the pressure chamber 26, and liquid 29 is supplied into the pressure chamber 26 from a common flow path (not shown in the figure).

[0050] The reference maintenance element P15 is a waveform element that maintains the volume of the pressure chamber 26, which has been expanded by the expansion element P14, at a reference volume for a certain period of time.

[0051] The control unit 21 generates a drive waveform 50, as shown in Figure 4, which ejects, for example, two droplets 24 per cycle, according to the print data, and applies it to the piezoelectric element 28.

[0052] Furthermore, it is preferable that the control unit 21 applies a drive waveform 50 to the piezoelectric element 28 that causes multiple droplets 24 discharged from the nozzle 23 in one cycle to land at mutually different positions in the scanning direction X. That is, it is preferable that the drive waveform 50 is a waveform that causes multiple droplets 24 discharged from the nozzle 23 in one cycle to land at mutually different positions in the scanning direction X. More specifically, it is preferable that the drive waveform 50 is a waveform that causes multiple droplets 24 to land at mutually different positions in the scanning direction X within the effective droplet area EA of one cell S.

[0053] Furthermore, it is preferable that the control unit 21 applies a drive waveform 50 to the piezoelectric element 28 that is adjusted so that the multiple droplets 24 ejected from the nozzle 23 in one cycle do not merge between ejection and droplet placement. In other words, it is preferable that the drive waveform 50 is a waveform adjusted so that the multiple droplets 24 ejected from the nozzle 23 in one cycle do not merge between ejection and droplet placement. More specifically, it is preferable that the drive waveform 50 is a waveform adjusted so that the multiple droplets 24 ejected from the nozzle 23 in one cycle do not merge before they land in the effective droplet placement area EA of a single cell S.

[0054] Furthermore, it is preferable that the control unit 21 applies a drive waveform 50 to the piezoelectric element 28 such that at least one of the discharge speed and discharge amount of the multiple droplets 24 discharged from the nozzle 23 in one cycle is the same among the multiple droplets 24. In other words, it is preferable that the drive waveform 50 is a waveform such that at least one of the discharge speed and discharge amount of the multiple droplets 24 discharged from the nozzle 23 in one cycle is the same among the multiple droplets 24.

[0055] In detail, the difference in discharge speed of the multiple droplets 24 discharged from the nozzle 23 in one cycle by the application of the drive waveform 50 is preferably 10% or less, and particularly preferably zero. A difference in discharge speed of zero means that the discharge speeds of the multiple droplets 24 are the same.

[0056] More specifically, the difference in discharge volume between the multiple droplets 24 ejected from the nozzle 23 in one cycle by the application of the drive waveform 50 is preferably 35% or less, more preferably 20% or less, and particularly preferably zero. A difference in discharge volume of zero means that the discharge volume between the multiple droplets 24 is the same.

[0057] Note that by adjusting the drive waveform 50 so that either the discharge speed or discharge volume of the multiple droplets 24 discharged from the nozzle 23 in one cycle is the same among the multiple droplets 24, the other may end up being different values ​​among the multiple droplets 24. In this case, the control unit 21 should adjust the drive waveform 50 so that, among the discharge speed and discharge volume of the multiple droplets 24, the discharge speed is given priority in being the same among the multiple droplets 24.

[0058] Furthermore, it is preferable that the control unit 21 satisfies the above conditions and adjusts so that the difference in the time between the droplets 24 ejected from the nozzle 23 in one cycle and their placement on each target substrate 40 becomes shorter.

[0059] Furthermore, it is preferable that the control unit 21 applies a drive waveform 50 to the piezoelectric element 28, which adjusts the discharge amount of each of the multiple droplets 24 so that the thickness of the liquid film formed by the deposition of multiple droplets 24 discharged from the nozzle 23 in one cycle reaches the target thickness.

[0060] The control unit 21 should adjust the amount dispensed per drop so that the thickness of the partial liquid film formed in the cell S of the substrate 40 by each of the multiple droplets 24 dispensed from the nozzle 23 in one cycle is equal to the thickness obtained by dividing the target film thickness in the cell S by the number of droplets dispensed in one cycle.

[0061] The control unit 21 can calculate the target film thickness using known methods, such as analyzing the print data. For example, the control unit 21 can determine the area of ​​each cell S and the target total amount of liquid 29 to be discharged per cell S based on the print data, and then calculate the thickness of the liquid 29 in the cell S when the target total amount of liquid 29 is discharged into the cell S of that area as the target film thickness.

[0062] The control unit 21 then adjusts the drive waveform 50 to satisfy at least one of the velocity conditions of the multiple droplets 24 discharged in one cycle, and the discharge volume conditions of the multiple droplets 24, and applies it to the piezoelectric element 28. As described above, the application of the drive waveform 50 to the piezoelectric element 28 by the control unit 21 should be performed when the substrate 40 to be discharged is being scanned at a constant speed in the scanning direction X relative to the liquid discharge head 22.

[0063] The velocity conditions are at least one of the following: multiple droplets 24 ejected from the nozzle 23 in one cycle are deposited at different positions in the scanning direction X; these multiple droplets 24 do not merge between ejection and deposition; and the ejection velocities of these multiple droplets 24 are the same.

[0064] The discharge volume conditions are at least one of the following: the discharge volume of multiple droplets 24 discharged from the nozzle 23 in one cycle is the same, and the thickness of the liquid film formed by the deposition of multiple droplets 24 discharged from the nozzle 23 in one cycle is equal to the target thickness.

[0065] The method for adjusting the drive waveform 50 that satisfies the above speed and discharge volume conditions will be specifically explained using Figure 4. As shown in Figure 4, the explanation will assume a configuration in which 2 droplets 24 are discharged in one cycle.

[0066] The position of the droplet 25 in the scanning direction X of the ejected droplet 24 is adjusted by the ejection speed of the droplet 24. Furthermore, adjustments to prevent the first droplet 24a and the second droplet 24b from merging between ejection and landing are also achieved by adjusting the ejection speed of the droplet 24.

[0067] The discharge speed of the droplet 24 is adjusted by the slopes of the contraction elements P8 and P12, which discharge each of the multiple droplets 24 (the first droplet 24a, the second droplet 24b) at the respective discharge timings (timing t1, timing t2) in the drive waveform 50. The larger the slope of the contraction element P8, the faster the discharge speed of the first droplet 24. Similarly, the larger the slope of the contraction element P12, the faster the discharge speed of the second droplet 24.

[0068] Furthermore, the discharge speeds of the multiple droplets 24 (the first droplet 24a, the second droplet 24b) can also be adjusted by adjusting the periods T5 and T6 in the drive waveform 50. Period T5 is the total time of the contraction element P8 and the contraction maintenance element P9. Period T6 is the total time of the expansion element P10 and the expansion maintenance element P11.

[0069] In detail, the discharge rate of the first droplet 24a is adjusted by adjusting the inclination of the contraction element P8 and the duration T5. The discharge rate of the second droplet 24b is adjusted by adjusting duration T5, duration T6, and the inclination of the contraction element P12.

[0070] The discharge volume of the droplet 24 is adjusted by the voltage difference between the start and end points of the contraction elements P8 and P12, which discharge each of the multiple droplets 24 (the first droplet 24a, the second droplet 24b) at the discharge timings (timing t1, timing t2) in the drive waveform 50.

[0071] Furthermore, the discharge volume of the first droplet 24a is also influenced by the adjustment of the waveform elements before the discharge of the first droplet 24a: the reference maintenance element P1, the pre-expansion element P2, the pre-expansion maintenance element P3, the pre-contraction element P4, the pre-maintenance element P5, the expansion element P6, and the expansion maintenance element P7. These reference maintenance elements P1, the pre-expansion element P2, the pre-expansion maintenance element P3, the pre-contraction element P4, the pre-maintenance element P5, the expansion element P6, and the expansion maintenance element P7 correspond to the pre-resonance elements before the discharge of the first droplet 24a.

[0072] Furthermore, the discharge volume of the second droplet 24a is also influenced by adjusting the timing of the start of the contraction element P12 to resonate with the residual vibrations in the pressure chamber 26 caused by the discharge of the first droplet 24a.

[0073] The control unit 21 can adjust the drive waveform 50 by combining these adjustments to satisfy at least one of the above-mentioned velocity conditions for the multiple droplets 24 discharged in one cycle, and the above-mentioned discharge volume conditions for the multiple droplets 24, and then apply it to the piezoelectric element 28.

[0074] Furthermore, if the liquid dispensing device 10 is equipped with multiple nozzles 23, the dispensing characteristics may differ for each nozzle 23. For this reason, the control unit 21 should adjust the drive waveform 50 for each nozzle 23 to satisfy at least one of the above-mentioned velocity conditions for the multiple liquid droplets 24 dispensed in one cycle and the above-mentioned dispensing volume conditions for the multiple liquid droplets 24, according to the dispensing and configuration of the nozzle 23, and apply it to the piezoelectric element 28 corresponding to the nozzle 23. The control unit 21 can acquire the dispensing characteristics for each nozzle 23 by a known method.

[0075] Returning to Figure 3, we continue the explanation.

[0076] The control unit 21 applies a drive waveform 50 to the piezoelectric element 28 of the liquid discharge head 22, which is scanned at a constant speed in the scanning direction X relative to the substrate 40 to be discharged. As a result, with one scan in the scanning direction X, droplets 24a (droplet 25a) and 24b (droplet 25b) are formed at different positions in the scanning direction X on one cell S from one nozzle 23.

[0077] Therefore, in the liquid dispensing device 10 of this embodiment, the number of scans of the nozzle 23 (liquid dispensing head 22) in the scanning direction X relative to the substrate 40 can be reduced in order to set the total amount of liquid 29 dispensed to the cells S provided on the substrate 40 to the amount that achieves the target film thickness.

[0078] For example, as described above, by applying a drive waveform 50 to the piezoelectric element 28 such that the thickness of the liquid film formed by the deposition of multiple droplets 24 ejected from the nozzle 23 in one cycle becomes the target thickness, it becomes possible to control the total amount of multiple droplets 24 ejected onto the cells S provided on the substrate 40 to achieve the target thickness in a single scan in the scanning direction X.

[0079] Next, an example of the information processing flow performed by the control unit 21 of this embodiment will be described.

[0080] Figure 5 is a flowchart showing an example of the information processing flow performed by the control unit 21 of the liquid dispensing device 10 in this embodiment.

[0081] The control unit 21 of the liquid dispensing device 10 acquires print data (step S100). For example, the control unit 21 acquires print data by generating print data using a known method. Alternatively, the control unit 21 may acquire print data by receiving print data from an external information processing device or storage device that is connected to it via a network or the like.

[0082] Based on the print data acquired in step S100, the control unit 21 generates a drive waveform 50 to be applied to each of the piezoelectric elements 28 corresponding to the plurality of nozzles 23 provided in the liquid ejection device 10 (step S102).

[0083] The control unit 21 scans the stage 42 with respect to the liquid ejection head 22 in the scanning direction X at a constant speed and applies the drive waveform 50 generated in step S102 to the corresponding piezoelectric element 28 to perform printing control (step S104). As a result of the process in step S104, two or more droplets 24 are ejected from the nozzle 23 in one cycle, and droplets 25 are formed by multiple nozzles 23 at different positions in the scanning direction X within one cell S, forming a liquid film with multiple droplets 25.

[0084] Then, this routine ends.

[0085] As described above, the liquid discharge device 10 of this embodiment comprises a liquid discharge head 22 and a control unit 21. The liquid discharge head 22 comprises a nozzle 23 that communicates with a pressure chamber 26 and discharges liquid droplets 24, a pressure chamber 26 that communicates with the nozzle 23, and a piezoelectric element 28 that changes the pressure inside the pressure chamber 26 via a diaphragm 27 that forms part of the wall of the pressure chamber 26. The control unit 21 controls the liquid discharge head 22. The control unit 21 applies a drive waveform 50 to the piezoelectric element 28 that causes the nozzle 23 to discharge liquid droplets 24 two or more times in one cycle.

[0086] In this case, when the conventional drive waveform was applied to the piezoelectric element 28, an increase in cycle time was a problem.

[0087] Figure 6 is a schematic diagram of an example of a conventional drive waveform 500.

[0088] The conventional drive waveform 500 is a waveform that represents the voltage (potential) transition required to eject one droplet 24 from the nozzle 23 in one cycle. The conventional drive waveform 500 does not include the expansion maintenance element P11, contraction element P12, contraction maintenance element P13, and expansion element P14 required to eject the second droplet 24b in the drive waveform 50 of this embodiment shown in Figure 4.

[0089] Therefore, one droplet 24 is ejected per cycle from the nozzle 23 corresponding to the piezoelectric element 28 to which the conventional drive waveform 500 is applied.

[0090] Therefore, when the conventional drive waveform 500 was applied to the piezoelectric element 28, it was necessary to perform numerous scans of the nozzle 23 (liquid discharge head 22) in the scanning direction X relative to the substrate 40 to be discharged. For this reason, in the conventional technology, an increase in the cycle time for manufacturing the workpiece was sometimes a problem.

[0091] On the other hand, in the liquid dispensing device 10 of this embodiment, a drive waveform 50 is applied to the piezoelectric element 28 to dispense droplets 24 from the nozzle 23 two or more times per cycle. Therefore, in the liquid dispensing device 10 of this embodiment, it is possible to reduce the number of scans in the scanning direction X required to achieve the desired film thickness.

[0092] Therefore, the liquid dispensing device 10 of this embodiment can shorten the cycle time.

[0093] Furthermore, in this embodiment, the liquid discharge head 22 is scanned relative to the discharge target substrate 40 in the scanning direction X. One cycle is the period of movement in the scanning direction X on the discharge target substrate 40 during which one nozzle 23 can discharge a droplet 24 from one cell S. More specifically, one cycle is the period during which one nozzle 23 passes over the droplet placement effective area EA of one cell S on the discharge target substrate 40 in the scanning direction X.

[0094] Therefore, in the liquid dispensing device 10 of this embodiment, by applying a drive waveform 50 to the liquid dispensing head 22 which is scanned relative to the substrate 40 to be dispensed in the scanning direction X, the dispensing of droplets 24 onto the cells S can be completed in a single scan in the scanning direction X. Thus, in the liquid dispensing device 10 of this embodiment, the number of scans in the scanning direction X required to achieve a total dispensing amount of liquid 29 onto the cells S provided on the substrate 40 to be dispensed can be reduced.

[0095] Furthermore, the control unit 21 of the liquid dispensing device 10 in this embodiment applies a drive waveform 50 to the piezoelectric element 28, which causes multiple liquid droplets 24 dispensed from the nozzle 23 in one cycle to land at different positions in the scanning direction X.

[0096] Therefore, multiple droplets 24 ejected from the nozzle 23 in one cycle land on different positions in the scanning direction X of the substrate 40 to be ejected. This improves the uniformity of the film thickness of the liquid film formed by the ejection of multiple droplets 24 in one cycle.

[0097] Furthermore, in the liquid dispensing device 10 of this embodiment, the uniformity of the film thickness of the liquid film formed by the dispensing of droplets 24 can be improved. Therefore, when the manufactured object produced by dispensing droplets 24 onto the substrate 40 is a display panel, brightness unevenness of the display panel can be suppressed.

[0098] Furthermore, the control unit 21 of this embodiment applies a drive waveform 50 to the piezoelectric element 28 that is adjusted so that the multiple droplets 24 ejected from the nozzle 23 in one cycle do not merge between ejection and landing.

[0099] Therefore, multiple droplets 24 ejected from the nozzle 23 in one cycle fly toward the substrate 40 as separate droplets 24 and land on the substrate 40. As a result, the uniformity of the film thickness of the liquid film formed by the ejection of multiple droplets 24 in one cycle can be improved.

[0100] Furthermore, in the liquid dispensing device 10 of this embodiment, a drive waveform 50 is applied to the piezoelectric element 28 to dispensing droplets 24 from the nozzle 23 two or more times per cycle. This makes it possible to ensure uniformity of the thickness of the liquid film formed by the deposition 25 of the droplets 24.

[0101] Figures 7A to 7D are explanatory diagrams of the liquid film 30 formed by applying a conventional drive waveform 500. Figures 7A to 7D show the state in which the conventional drive waveform 500 is applied to the piezoelectric element 28 and the liquid discharge head 22 is scanned multiple times in the scanning direction X so that a liquid film 30 of the target thickness is formed in the cell S. The conventional drive waveform 500 is the conventional drive waveform 500 shown in Figure 6.

[0102] As shown in Figure 7A, when the conventional drive waveform 500 is applied to the piezoelectric element 28, one droplet 24 is ejected with each scan of the cell S in the scanning direction X, and a droplet 25 is formed inside the cell S. The droplet 25 inside the cell S spreads and wets, forming a liquid film 30 inside the cell S (Figure 7B). Next, the liquid ejection head 22 is scanned again in the scanning direction X, and the conventional drive waveform 500 is applied to the piezoelectric element 28, causing one droplet 24 to be ejected onto the liquid film 30 inside the cell S, and a droplet 25 is formed on the liquid film 30 (Figure 7C). Then, the liquid film 30 formed by the droplet 25 ejected during the current scan in the scanning direction X is layered on top of the liquid film 30 formed by the droplet 25 ejected during the previous scan in the scanning direction X (see Figures 7C and 7D).

[0103] Therefore, as shown in Figure 7D, in the conventional technology, one drop 25 is deposited on the cell S for each of the multiple scanning directions X. As a result, the shape of the liquid film 30 becomes irregular and the film thickness becomes non-uniform due to the influence of wettability between the liquid films 30 caused by the deposition 25 in each scanning direction X.

[0104] Figures 8A to 8B are explanatory diagrams of the liquid film 30 formed by the application of the drive waveform 50 in this embodiment. Figures 8A to 8B are explanatory diagrams in which multiple droplets 24 are ejected in one cycle so that a liquid film 30 of the target thickness is formed in the cell S by applying the drive waveform 50 to the piezoelectric element 28 during one scan of the liquid ejection head 22 in the scanning direction X.

[0105] As shown in Figure 8A, when the drive waveform 50 is applied to the piezoelectric element 28, multiple droplets 24 are ejected to different locations within the cell S during a single scan in the scanning direction X relative to the cell S, forming droplets 25. The multiple droplets 25, which are deposited at different locations within the cell S, spread out to form a liquid film 30 (Figure 8B).

[0106] As shown in Figure 8B, in this embodiment, multiple droplets 25 are deposited at different positions within the cell S in a single scanning direction X, thereby improving the uniformity of the film thickness of the liquid film 30 formed by the multiple droplets 25.

[0107] Furthermore, the control unit 21 applies a drive waveform 50 to the piezoelectric element 28 such that at least one of the discharge speed and discharge amount of the plurality of droplets 24 discharged from the nozzle 23 in one cycle is the same among the plurality of droplets 24.

[0108] Therefore, the position of the droplet 25 formed by each of the multiple droplets 24 discharged in one cycle, and the thickness of the liquid film formed by the droplets 25, can be efficiently adjusted.

[0109] Furthermore, the control unit 21 applies a drive waveform 50 to the piezoelectric element 28, adjusting the discharge amount of each of the multiple droplets 24 so that the thickness of the liquid film formed by the deposition 25 of the multiple droplets 24 discharged from the nozzle 23 in one cycle reaches the target thickness.

[0110] Therefore, the liquid dispensing device 10 of this embodiment can dispense droplets 24 that achieve the target film thickness with a single scan in the scanning direction X, thereby reducing the number of scans in the scanning direction X. [Examples]

[0111] The liquid dispensing device 10 of this embodiment will be described in detail below with reference to examples. However, the liquid dispensing device 10 of this embodiment is not limited to the following examples.

[0112] Figures 9A to 9D show the evaluation results of the discharge speeds of the first droplet 24a and the second droplet 24b, respectively. Figures 9A to 9D show the evaluation results of the discharge speeds of the first droplet 24a and the second droplet 24b, respectively, when the periods T5, T6, and T7 are adjusted in the drive waveform 50 shown in Figure 4. Period T4 is the total time of the expansion element P6 and the expansion maintenance element P7. Period T7 is the total time of the contraction element P12 and the contraction maintenance element P13.

[0113] Figure 9A is an explanatory diagram showing the measurement results of the discharge speeds of the first droplet 24a and the second droplet 24b when the period T5 in the drive waveform 50 is varied. In Figure 9A, the horizontal axis represents the period T5, and the vertical axis represents the discharge speed of the droplet 24. Figure 9A shows the measurement results of the discharge speeds of the first droplet 24a and the second droplet 24b discharged from the nozzle 23 corresponding to the piezoelectric element 28 when the drive waveform 50, in which only the period T5 is varied while all other conditions are kept constant, is applied to the piezoelectric element 28.

[0114] As shown in Figure 9A, varying the period T5 changed the respective dispensing velocities of the first droplet 24a and the second droplet 24b. In the evaluation results shown in Figure 9A, when the period T5 was 1.5 × period T4, the velocities of the first droplet 24a and the second droplet 24b became approximately the same.

[0115] Figure 9B is an explanatory diagram showing the evaluation results of the discharge speeds of the first droplet 24a and the second droplet 24b when the period T6 in the drive waveform 50 is varied. In Figure 9B, the horizontal axis represents the period T6, and the vertical axis represents the discharge speed of the droplet 24. Figure 9B shows the measurement results of the discharge speeds of the first droplet 24a and the second droplet 24b discharged from the nozzle 23 corresponding to the piezoelectric element 28 when the drive waveform 50, in which only the period T6 is varied while all other conditions are kept constant, is applied to the piezoelectric element 28.

[0116] As shown in Figure 9B, changing the period T6 mainly altered the discharge velocity of the second droplet 24b. In the evaluation results shown in Figure 9B, when period T6 was 0.9 × period T4, the velocities of the first droplet 24a and the second droplet 24b were approximately the same and the fastest.

[0117] Figure 9C is an explanatory diagram showing the evaluation results of the discharge speeds of the first droplet 24a and the second droplet 24b when the period T7 in the drive waveform 50 is varied. In Figure 9C, the horizontal axis represents the period T7, and the vertical axis represents the discharge speed of the droplet 24. Figure 9C shows the measurement results of the discharge speeds of the first droplet 24a and the second droplet 24b discharged from the nozzle 23 corresponding to the piezoelectric element 28 when the drive waveform 50, in which only the period T7 is varied while all other conditions are kept constant, is applied to the piezoelectric element 28.

[0118] As shown in Figure 9C, changing the period T7 did not change the discharge velocity of either the first droplet 24a or the second droplet 24b. Therefore, it can be said that adjusting the period T7 does not contribute to the discharge velocity of the first droplet 24a or the second droplet 24b. However, when the period T7 was adjusted to 2.3 × period T4, the residual vibration generated in the pressure chamber 26 due to the discharge of the first droplet 24a and the second droplet 24b was minimized. Therefore, it can be said that adjusting the period T7 contributes to the adjustment of residual vibration.

[0119] Figure 9D is an explanatory diagram showing the measurement results of the discharge amounts of the first droplet 24a and the second droplet 24b when the period T7 in the drive waveform 50 is varied. In Figure 9D, the horizontal axis represents the period T7, and the vertical axis represents the discharge amount of droplet 24. Figure 9D shows the measurement results of the discharge amounts of the first droplet 24a and the second droplet 24b discharged from the nozzle 23 corresponding to the piezoelectric element 28 when the drive waveform 50, in which only the period T7 is varied while all other conditions are kept constant, is applied to the piezoelectric element 28.

[0120] As shown in Figure 9D, even when the period T7 was changed, there was no change in the discharge volume of both the first droplet 24a and the second droplet 24b. However, the discharge volume of the second droplet 24b was greater than that of the first droplet 24a. Therefore, it can be said that if the relationship between the velocities of the first droplet 24a and the second droplet 24b is adjusted to satisfy the above velocity conditions, the volumes of the first droplet 24a and the second droplet 24b may not be the same, and the discharge volume of the second droplet 24b may be greater.

[0121] Here, the ejection speeds of droplets 24a and 24b also contribute to the placement of each droplet 24a and 24b on the target substrate 40. Therefore, as described above, the control unit 21 should generate a drive waveform 50 by adjusting the inclination of the contraction element P8, the period T5, the period T6, and the inclination of the contraction element P12, etc., so as to preferentially satisfy the speed condition over the ejection volume condition, and apply it to the piezoelectric element 28.

[0122] Figures 10A to 10C show the evaluation results of the allowable ranges for the difference in discharge speed and the difference in discharge volume.

[0123] Figure 10A shows the evaluation results when the drive waveform 50 shown in Figure 4 is applied to each of the 150 nozzles 23 provided on the liquid discharge head 22, representing the discharge volume of each droplet 24a and droplet 24b discharged from each nozzle 23, as well as the total discharge volume for each nozzle 23. In Figure 10A, the horizontal axis represents the identification number of the nozzle 23, and the vertical axis represents the discharge volume of the droplet 24. The discharge volume is expressed in volume.

[0124] As shown in Figure 10A, the discharge volume of the first droplet 24a ejected from each of the multiple nozzles 23 was within the range of 2.2 pl ± 7.5%. The discharge volume of the second droplet 24b ejected from each of the multiple nozzles 23 was within the range of 2.6 pl ± 5.1%. The total discharge volume of droplets 24a and 24b ejected from each of the multiple nozzles 23 was 4.8 pl ± 2.6%. Therefore, the acceptable range for the difference in discharge volume between the first droplet 24a and the second droplet 24b was 10% to 35%.

[0125] In other words, as described in the above embodiment, the difference in discharge volume between multiple droplets 24 discharged from the nozzle 23 in one cycle, which is included in the discharge volume conditions, is preferably 35% or less, more preferably 20% or less, and particularly preferably zero.

[0126] Figure 10B shows the evaluation results representing the discharge speeds of droplets 24a and 24b discharged from each of the 150 nozzles 23 provided on the liquid discharge head 22, when the drive waveform 50 shown in Figure 4 is applied to each of the piezoelectric elements 28 corresponding to each of the nozzles 23. In Figure 10B, the horizontal axis represents the identification number of the nozzle 23, and the vertical axis represents the discharge speed of the droplet 24.

[0127] As shown in Figure 10B, the discharge velocity of the first droplet 24a ejected from each of the multiple nozzles 23 was within the range of 6.0 m / s ± 18%. The discharge velocity of the second droplet 24b ejected from each of the multiple nozzles 23 was within the range of 4.9 m / s ± 20%.

[0128] Figure 10C shows the evaluation results representing the time difference (deposition time difference) between droplet 24a and droplet 24b ejected from each nozzle 23 and their placement on the target substrate 40, when the drive waveform 50 shown in Figure 4 is applied to each of the piezoelectric elements 28 corresponding to each of the 150 nozzles 23 provided on the liquid ejection head 22. In Figure 10C, the horizontal axis represents the identification number of the nozzle 23, and the vertical axis represents the deposition time difference. The evaluation shown in Figure 10C was performed with a distance of 0.45 mm between the nozzle 23 and the target substrate 40. Figure 10C shows the results for when the length of one period of the drive waveform 50 shown in Figure 4 is 40 μsec (frequency 25 kHz) and when the length of one period is 33 μsec (frequency 30 kHz).

[0129] As shown in Figure 10C, when the drive waveform 50 with a period of 40 μsec (frequency 25 kHz) was applied, there was a sufficient difference in the droplet placement time between droplet 24a and droplet 24b, and it can be said that no merging occurred between droplet 24a and droplet 24b before droplet placement. On the other hand, when the drive waveform 50 with a period of 33 μsec (frequency 30 kHz) was applied, there was zero difference in the droplet placement time between droplet 24a and droplet 24b. Therefore, from the results in Figures 10B and 10C, it can be said that when the drive waveform 50 with a period of 33 μsec (frequency 30 kHz) is applied, merging between droplet 24a and droplet 24b is suppressed if the difference in discharge speed between droplet 24a and droplet 24b is 10% or less.

[0130] Therefore, the allowable range for the difference in discharge speed between the first droplet 24a and the second droplet 24b is 10% or less. In other words, as described in the above embodiment, the difference in discharge speed of the multiple droplets 24 discharged from the nozzle 23 in one cycle, which is included in the speed condition, is preferably 10% or less among the multiple droplets 24, and is particularly preferably zero.

[0131] Figure 11 shows the evaluation results of conventional discharge using the conventional drive waveform 500 and discharge using the drive waveform 50 of this embodiment.

[0132] Figure 11 shows the evaluation results of droplet deposition 25 by droplets 24 ejected from a nozzle 23 corresponding to a piezoelectric element 28, when the conventional drive waveform 500 shown in Figure 6 is applied to a substrate 40 to be ejected, which is scanned at a constant speed in the scanning direction X, as a conventional ejection method.

[0133] Furthermore, Figure 11 shows the evaluation results of droplet deposition 25 by droplets 24 ejected from a nozzle 23 corresponding to a piezoelectric element 28, when the drive waveform 50 shown in Figure 4 is applied to the piezoelectric element 28 on a substrate 40 to be ejected, which is scanned at a constant speed in the scanning direction X, as part of the ejection method in this embodiment.

[0134] Furthermore, Figure 11 shows the evaluation results of droplet deposition 25 by droplets 24 discharged from each of the two nozzles 23 when a drive waveform 50 is applied to the piezoelectric element 28 corresponding to each of the two nozzles 23 as the discharge method of this embodiment.

[0135] As shown in Figure 11, it was confirmed that the discharge speeds of the first droplet 24a and the second droplet 24b discharged from the nozzle 23 corresponding to the piezoelectric element 28 to which the drive waveform 50 of this embodiment is applied are approximately the same as the discharge speed of a single droplet 24 discharged from the nozzle 23 corresponding to the piezoelectric element 28 to which the conventional drive waveform 500 is applied.

[0136] Furthermore, as shown in Figure 11, even when the same drive waveform 50 was applied to each of the two piezoelectric elements 28, the difference in droplet placement time and droplet placement position between droplets 25a and 25b of droplets 24a and 24b discharged from nozzles 23 corresponding to each of the two piezoelectric elements 28 differed between the nozzles 23.

[0137] Therefore, it is preferable to adjust the drive waveform 50 for each nozzle 23 so as to satisfy at least one of the above speed conditions and discharge volume conditions according to the characteristics of the nozzle 23.

[0138] Figure 12 shows the evaluation results of conventional discharge using the conventional drive waveform 500 and discharge using the drive waveform 50 of this embodiment.

[0139] Figure 12 shows the evaluation results of the ejection speed and ejection angle of droplets 24 ejected from a nozzle 23 corresponding to a piezoelectric element 28 by applying the conventional drive waveform 500 shown in Figure 6 to a substrate 40 to be ejected, which is scanned at a constant speed in the scanning direction X, as a conventional ejection method.

[0140] Furthermore, Figure 12 shows the evaluation results of the ejection speed and ejection angle of droplets 24 ejected from the nozzle 23 corresponding to the piezoelectric element 28 by applying the drive waveform 50 shown in Figure 4 to the piezoelectric element 28 on the ejection target substrate 40 which is scanned in the scanning direction X at a constant speed, as is the ejection method of this embodiment.

[0141] In Figure 12, the horizontal axis of the graph represents the identification number of nozzle 23. The vertical axis of the upper graph in Figure 12 represents the discharge speed. The vertical axis of the lower graph in Figure 12 represents the discharge angle.

[0142] As shown in Figure 12, it was confirmed that the discharge speed and discharge angle of the first droplet 24a and the second droplet 24b discharged from the nozzle 23 corresponding to the piezoelectric element 28 to which the drive waveform 50 of this embodiment is applied are substantially the same as the discharge speed and discharge angle of the first droplet 24 discharged from the nozzle 23 corresponding to the piezoelectric element 28 to which the conventional drive waveform 500 is applied.

[0143] Figure 13 shows the evaluation results of droplet deposition 25 by droplets 24 discharged from nozzle 23 upon application of drive waveform 50.

[0144] Figure 13 shows the evaluation results of droplet deposition 25 by droplets 24 ejected from nozzle 23 corresponding to piezoelectric element 28 when the drive waveform 50 shown in Figure 4 is applied to the piezoelectric element 28 twice in succession in a time series. As shown in Figure 13, when the target substrate 40 is scanned at a constant speed in the scanning direction X and the drive waveform 50 is applied to the piezoelectric element 28 twice in succession, droplets 25a and 25b corresponding to droplets 24a and 24b from the first drive waveform 50, and droplets 25c and 25d corresponding to droplets 24a and 24b from the second drive waveform 50, are formed at different positions in the scanning direction X on the target substrate 40.

[0145] The difference in droplet placement time between droplet placement 25a and droplet placement 25b in the scanning direction X was 11 μsec. Furthermore, the difference in droplet placement time between droplet placement 25a and droplet placement 25d in the scanning direction X was 33 μsec. Also, the difference in droplet placement time between droplet placement 25c and droplet placement 25d in the scanning direction X was 11 μsec.

[0146] Therefore, by applying the drive waveform 50 of this embodiment to the piezoelectric element 28, it is possible to eject multiple droplets 24 within one cycle at a high frequency of 90 kHz or higher.

[0147] Next, an example of the hardware configuration of the control unit 21 of the liquid dispensing device 10 in this embodiment will be described.

[0148] Figure 14 is a hardware configuration diagram of an example of the control unit 21 of the liquid dispensing device 10 in this embodiment.

[0149] The control unit 21 of the liquid dispensing device 10 in this embodiment has a CPU 10A, ROM (Read Only Memory) 10B, RAM (Random Access Memory) 10C, and I / F unit 10D, etc., all interconnected by a bus 10E, and has a hardware configuration that uses a normal computer.

[0150] The CPU 10A is an arithmetic unit that controls the control unit 21 of the liquid dispensing device 10 in this embodiment. The ROM 10B stores programs and the like that realize information processing by the CPU 10A. The RAM 10C stores data necessary for various processes performed by the CPU 10A. The I / F unit 10D is an interface for sending and receiving data.

[0151] In the control unit 21 of the liquid dispensing device 10 of this embodiment, the CPU 10A reads a program from the ROM 10B onto the RAM 10C and executes it, thereby realizing each of the above-mentioned functional units on the computer. The program for executing each of the above-mentioned processes performed by the control unit 21 of the liquid dispensing device 10 of this embodiment may be stored in the HDD (hard disk drive). Alternatively, the program for executing each of the processes described later, performed by the control unit 21 of the liquid dispensing device 10 of this embodiment, may be pre-installed and provided in the ROM 10B.

[0152] Furthermore, the program for executing the information processing performed by the control unit 21 of the liquid dispensing device 10 in this embodiment may be provided as a computer program product by being stored in an installable or executable file format on a computer-readable storage medium such as a CD-ROM, CD-R, memory card, DVD (Digital Versatile Disk), or flexible disk (FD). Alternatively, the program for executing the information processing performed by the control unit 21 of the liquid dispensing device 10 in this embodiment may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Alternatively, the program for executing the information processing performed by the control unit 21 of the liquid dispensing device 10 in this embodiment may be provided or distributed via a network such as the Internet.

[0153] Although embodiments of this disclosure have been described above, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents.

[0154] Furthermore, this technology can also be configured as follows. <Note> (1) A liquid discharge head comprising a nozzle that communicates with a pressure chamber and discharges droplets, a pressure chamber that communicates with the nozzle, and a piezoelectric element that changes the pressure inside the pressure chamber via a diaphragm that forms part of the wall of the pressure chamber, A control unit for controlling the liquid discharge head, Equipped with, The control unit, A drive waveform is applied to the piezoelectric element that causes droplets to be ejected from the nozzle two or more times in one cycle. Liquid discharge device. (2) The liquid discharge head is scanned relative to the discharge target substrate on which the cells, which are the discharge target area, are provided, in the scanning direction. The aforementioned period is, The period of movement in the scanning direction on the substrate to be ejected, during which a droplet can be ejected from one cell by one nozzle. The liquid dispensing device described in (1) above. (3) The control unit, The drive waveform, which causes multiple droplets ejected from the nozzle in one cycle to land at different positions in the scanning direction, is applied to the piezoelectric element. A liquid dispensing device as described in (1) or (2) above. (4) The control unit, The drive waveform, which is adjusted so that the multiple droplets ejected from the nozzle in one cycle do not merge between ejection and contact with the surface, is applied to the piezoelectric element. A liquid dispensing device as described in any one of the above (1) to (3). (5) The control unit, The driving waveform applied to the piezoelectric element is such that at least one of the discharge speed and discharge volume of the plurality of droplets discharged from the nozzle in one cycle is the same among the plurality of droplets. A liquid dispensing device as described in any one of the above (1) to (4). (6) The control unit, The drive waveform is applied to the piezoelectric element, adjusting the discharge amount of each of the multiple droplets so that the thickness of the liquid film formed by the deposition of multiple droplets discharged from the nozzle in one cycle reaches the target thickness. A liquid dispensing device as described in any one of the above (1) to (5). (7) A printing method performed by a liquid dispensing device comprising a liquid dispensing head that includes a nozzle communicating with a pressure chamber for dispensing droplets, a pressure chamber communicating with the nozzle, and a piezoelectric element that changes the pressure inside the pressure chamber via a diaphragm constituting part of the wall of the pressure chamber, A drive waveform is applied to the piezoelectric element that causes droplets to be ejected from the nozzle two or more times in one cycle. Printing method. (8) A liquid discharge program to be executed by a computer that controls a liquid discharge head comprising a nozzle that communicates with a pressure chamber and discharges liquid droplets, a pressure chamber that communicates with the nozzle, and a piezoelectric element that changes the pressure inside the pressure chamber via a diaphragm that forms part of the wall of the pressure chamber, The process includes the step of applying a drive waveform to the piezoelectric element that causes droplets to be ejected from the nozzle two or more times in one cycle, Liquid dispensing program. [Explanation of Symbols]

[0155] 10 Liquid dispensing device 21 Control Unit 23 nozzles 26 Pressure chamber 27 Diaphragm 28 Piezoelectric element 24 droplets 25 Droplet 40. Substrates to be dispensed 50 Drive waveform S cell

Claims

1. A liquid discharge head comprising a nozzle that communicates with a pressure chamber and discharges droplets, a pressure chamber that communicates with the nozzle, and a piezoelectric element that changes the pressure inside the pressure chamber via a diaphragm that forms part of the wall of the pressure chamber, A control unit for controlling the liquid discharge head, Equipped with, The control unit, A drive waveform is applied to the piezoelectric element that causes droplets to be ejected from the nozzle two or more times in one cycle. Liquid discharge device.

2. The liquid discharge head is scanned relative to the discharge target substrate on which the cells, which are the discharge target area, are provided, in the scanning direction. The aforementioned period is, The period of movement in the scanning direction on the substrate to be ejected is such that a droplet can be ejected from one cell by one nozzle. The liquid dispensing device according to claim 1.

3. The control unit, The drive waveform, which causes multiple droplets ejected from the nozzle in one cycle to land at different positions in the scanning direction, is applied to the piezoelectric element. The liquid dispensing device according to claim 1.

4. The control unit, The drive waveform, which is adjusted so that the multiple droplets ejected from the nozzle in one cycle do not merge between ejection and contact with the surface, is applied to the piezoelectric element. The liquid dispensing device according to claim 1.

5. The control unit, The driving waveform applied to the piezoelectric element is such that at least one of the discharge speed and discharge volume of the plurality of droplets discharged from the nozzle in one cycle is the same among the plurality of droplets. The liquid dispensing device according to claim 1.

6. The control unit, The drive waveform is applied to the piezoelectric element, adjusting the discharge amount of each of the multiple droplets so that the thickness of the liquid film formed by the deposition of multiple droplets discharged from the nozzle in one cycle reaches the target thickness. The liquid dispensing device according to claim 1.

7. A printing method performed by a liquid dispensing device comprising a liquid dispensing head that includes a nozzle communicating with a pressure chamber for dispensing droplets, a pressure chamber communicating with the nozzle, and a piezoelectric element that changes the pressure inside the pressure chamber via a diaphragm constituting part of the wall of the pressure chamber, A drive waveform is applied to the piezoelectric element that causes droplets to be ejected from the nozzle two or more times in one cycle. Printing method.

8. A liquid discharge program to be executed by a computer that controls a liquid discharge head comprising a nozzle that communicates with a pressure chamber and discharges liquid droplets, a pressure chamber that communicates with the nozzle, and a piezoelectric element that changes the pressure inside the pressure chamber via a diaphragm that forms part of the wall of the pressure chamber, The process includes the step of applying a drive waveform to the piezoelectric element that causes droplets to be ejected from the nozzle two or more times in one cycle, Liquid dispensing program.

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