Patent Publication Number: US-11376847-B2

Title: Liquid droplet ejection device and liquid droplet ejection method

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application (bypass route) based upon PCT/JP2020/010368 filed on Mar. 10, 2020 and claims the benefit of priority to Japanese Patent Application No. 2019-084568 filed on Apr. 25, 2019, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to a liquid droplet ejection device and a liquid droplet ejection method. 
     BACKGROUND 
     In recent years, inkjet printing technology has been applied to industrial processes. For example, a color filter manufacturing process for a liquid crystal display is an example. As an inkjet printing technique, a so-called piezo type head, which ejects a liquid droplet by mechanical pressure or vibration, has been conventionally used, but an electrostatic ejection type inkjet heads, which can eject a finer liquid droplet, is drawing attention. Japanese Unexamined Patent Application Publication No. H10-34967 discloses an electrostatic ejection type inkjet recording device. 
     SUMMARY 
     According to an embodiment of the present disclosure, a liquid droplet ejection device includes at least one first liquid droplet ejection unit including a first liquid holding unit and a first tip, the first liquid holding unit configured to hold a first liquid, and the first tip configured to eject a first liquid in the first liquid holding unit as a first liquid droplet onto an object; at least one second liquid droplet ejection unit including a second liquid holding unit and a second tip, the second liquid holding unit configured to hold a second liquid, and the second tip configured to eject the second liquid in the second liquid holding unit as a second liquid droplet differing from the first liquid droplet onto the object; an object holding unit configured to hold the object; and a driving unit configured to move the first tip and the second tip in a first direction relative to the object holding unit. The first tip is arranged in the first direction relative to the second tip. 
     In the above liquid droplet ejection device, the at least one first liquid droplet ejection unit includes a plurality of first liquid droplet ejection units arranged in a direction intersecting with respect to a direction in which the first liquid droplet ejection unit moves. 
     In the above liquid droplet ejection device, the at least one first liquid droplet ejection unit extends in a direction intersecting with respect to a direction in which the at least one first liquid droplet ejection unit moves. 
     In the above liquid droplet ejection device, the at least one second liquid droplet ejection unit includes a plurality of second liquid droplet ejection units arranged in a direction intersecting with respect to a direction in which the at least one first liquid droplet ejection unit moves. 
     In the above liquid droplet ejection device, an inner diameter of the first tip in the at least one first liquid droplet ejection unit is larger than an inner diameter of the second tip in the at least one second liquid droplet ejection unit. 
     In the above liquid droplet ejection device, the at least one first liquid droplet ejection unit has a piezo type nozzle head, and the at least one second liquid droplet ejection unit has an electrostatic ejection type nozzle head. 
     According to an embodiment of the present disclosure, a liquid droplet ejection method includes ejecting a first liquid droplet for surface treatment from a first liquid droplet ejection unit onto a first region of an object; ejecting a second liquid droplet for forming a pattern from a second liquid droplet ejection unit onto the first region, the second liquid droplet being more viscous than the first liquid droplet, and the second liquid droplet ejection unit different from the first liquid droplet ejection unit; and ejecting the first liquid droplet from the first liquid droplet ejection unit onto a second region in synchronized with ejecting the second liquid droplet from the second liquid droplet ejection unit, the second region being different from the first region. 
     In the above liquid droplet ejection method, the second liquid droplet is ejected in a response to a predetermined condition being satisfied. 
     In the above liquid droplet ejection method, the predetermined condition includes an information related to an elapsed time after the first liquid droplet was ejected to the first region, or an information related to a thickness of the first liquid droplet. 
     In the above liquid droplet ejection method, the region in which the first liquid droplet is ejected is larger than a pattern size formed by the second liquid droplet. 
     In the above liquid droplet ejection method, the pattern size formed by the second liquid droplet is 100 nm or more and 500 μm or less. 
     In the above liquid droplet ejection method, the first liquid droplet has volatility. 
     In the above liquid droplet ejection method, a surface resistance of the first liquid droplet is 10 6 Ω/sq or more and 10 11 Ω/sq or less. 
     By using an embodiment of the present disclosure, it is possible to eject liquid droplets easily and stably onto the object surface. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic view of a liquid droplet ejection device according to an embodiment of the present disclosure; 
         FIG. 2  is a cross-sectional view of a liquid droplet ejection method according to an embodiment of the present disclosure; 
         FIG. 3  is a cross-sectional view of a liquid droplet ejection method according to an embodiment of the present disclosure; 
         FIG. 4  is a cross-sectional view of a liquid droplet ejection method according to an embodiment of the present disclosure; 
         FIG. 5  is a cross-sectional view of a liquid droplet ejection method according to an embodiment of the present disclosure; 
         FIG. 6  is a top view of patterns formed by a liquid droplet ejection method according to an embodiment of the present disclosure; 
         FIG. 7  is a cross-sectional view of a liquid droplet ejection method according to an embodiment of the present disclosure; 
         FIG. 8  is a cross-sectional view of a liquid droplet ejection method according to an embodiment of the present disclosure; 
         FIG. 9  is a cross-sectional view of a liquid droplet ejection method according to an embodiment of the present disclosure; 
         FIG. 10  is a cross-sectional view of a liquid droplet ejection method according to an embodiment of the present disclosure; 
         FIG. 11  is a top view of patterns formed by a liquid droplet ejection method according to an embodiment of the present disclosure; 
         FIG. 12  is a schematic view of a liquid droplet ejection device according to an embodiment of the present disclosure; 
         FIG. 13  is a schematic view of a liquid droplet ejection device according to an embodiment of the present disclosure; 
         FIG. 14  is a top view of patterns formed by a liquid droplet ejection method according to an embodiment of the present disclosure; 
         FIG. 15  is a top view of a second liquid droplet nozzle according to an embodiment of the present disclosure; and 
         FIG. 16A  is an enlarged top view of a second liquid droplet nozzle according to an embodiment of the present disclosure; and 
         FIG. 16B  is a cross-sectional view of a second liquid droplet nozzle according to an embodiment of the present disclosure. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the present disclosure disclosed in the present application will be described with reference to the drawings. However, the present disclosure can be implemented in various forms without departing from the gist thereof, and should not be construed as being limited to the description of the following exemplary embodiments. 
     In the drawings referred to in the present exemplary embodiments, the same portions or portions having similar functions are denoted by the identical signs or similar signs (signs each formed simply by adding A, B, etc. to the end of a number), and a repetitive description thereof may be omitted. For the convenience of description, the dimensional ratio of the drawings may be different from the actual ratio, or a part of the configuration may be omitted from the drawings. 
     Furthermore, in the detailed description of the present disclosure, in defining the positional relationship between one component and another, the terms “above” and “below” include not only the case of being positioned directly above or below one component, but also the case of interposing another component therebetween, unless otherwise specified. 
     In the case of the electrostatic ejection type inkjet head, there are cases in which it is difficult to eject the ink due to the electrostatic charging of an object, or the ink does not land at a desired position because it is affected by the effect of the electric field strength distributions due to an unevenness on the object. 
     In particular, in the case of the charging of the object itself or the pattern applied to the object affects the charging, or in the case of there is a difference of the energy between the pattern surface and the object surface, the ink may not fit well. 
     The present disclosure is to eject liquid droplets easily and stably onto an object surface. 
     First Embodiment 
     [1-1. Configuration of Liquid Droplet Ejection Device  100 ] 
       FIG. 1  is a schematic view of a liquid droplet ejection device  100  according to an embodiment of the present disclosure. 
     The liquid droplet ejection device  100  includes a control unit  110 , a storage unit  115 , a power supply unit  120 , a driving unit  130 , a first liquid droplet ejection unit  140 , a second liquid droplet ejection unit  150 , and an object holding unit  160 . 
     The control unit  110  includes CPU (Central Processing Unit), ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), or other calculation processing circuitry. The control unit  110  controls the ejection processes of the first liquid droplet ejection unit  140  and the second liquid droplet ejection unit  150  by using preset liquid droplet ejection programs. 
     The control unit  110  controls an ejection timing of a first liquid droplet  147  (see  FIG. 3 ) from the first liquid droplet ejection unit  140  and an ejection timing of the second liquid droplet  157  (see  FIG. 5 ) of the second liquid droplet ejection unit  150 . As described in detail later, the ejection of the first liquid droplet  147  by the first liquid droplet ejection unit  140  and the ejection of the second liquid droplet  157  by the second liquid droplet ejection unit  150  are synchronized with each other. “Synchronizing” in the present embodiment means that the first liquid droplet  147  and the second liquid droplet  157  are ejected at a prescribed time period. In this example, the first liquid droplet  147  and the second liquid droplet  157  are ejected simultaneously. The control unit  110  controls the second liquid droplet ejection unit  150  to eject the second liquid droplet  157  in the first region when the first liquid droplet ejection unit  140  moves from the first region of an object  200  to the second region of the object  200 , on which the first liquid droplet  147  is ejected. 
     The storage unit  115  has a function as a data base for storing a liquid droplet ejecting program and various types of data used in the liquid droplet ejecting program. Memories, SSDs, or storable elements are used for the storage unit  115 . 
     The power supply unit  120  is connected to the control unit  110 , the driving unit  130 , the first liquid droplet ejection unit  140 , and the second liquid droplet ejection unit  150 . The power supply unit  120  applies a voltage to the first liquid droplet ejection unit  140  and the second liquid droplet ejection unit  150  based on a signal input from the control unit  110 . In this example, the power supply unit  120  applies a pulsed voltage to the second liquid droplet ejection unit  150 . The voltage is not limited to the pulse voltage, and a constant voltage may be applied at all times. 
     The driving unit  130  includes a driving member such as a motor, a belt, and a gear. Based on an instruction from the control unit  110 , the driving unit  130  moves the first liquid droplet ejection unit  140  and the second liquid droplet ejection unit  150  (more specifically, a nozzle tip  141   a  of a first liquid droplet nozzle  141  and a nozzle tip  151   a  of a second liquid droplet nozzle  151  described later) in one direction (in this example, first direction D 1 ) with respective to the object holding unit  160 . 
     The first liquid droplet ejection unit  140  includes the first liquid droplet nozzle  141  and a first ink tank  143  (also referred to as a first liquid holding unit). In this embodiment, a piezo type ink jet nozzle is used as the first liquid droplet nozzle  141 . A piezoelectric element  145  is provided at the top of the first liquid droplet nozzle  141 . The piezoelectric element  145  is electrically connected to the power supply unit  120 . The piezoelectric element  145  ejects the first liquid droplet  147  from the nozzle tip  141   a  (also referred to as a first tip) of the first liquid droplet nozzle  141  with the first liquid held in the first ink tank  143  by pressing the first liquid droplet  147  by the voltage applied from the power supply unit  120 . 
     The first liquid droplet nozzle  141  in the first liquid droplet ejection unit  140  is provided perpendicularly to the front face of the object  200 . 
     The inner diameter of the nozzle tip  141   a  in the first liquid droplet nozzle  141  is desirably larger than the inner diameter of the nozzle tip  151   a  in the second liquid droplet nozzle  151 . This makes it possible to eject the first liquid droplet  147  in a wide region while suppressing clogging of the nozzle. 
     The second liquid droplet ejection unit  150  includes the second liquid droplet nozzle  151  and a second ink tank  153  (also referred to as a second liquid holding unit). An electrostatic ejection type inkjet nozzle is used for the second liquid droplet nozzle  151 . The inner diameter of the nozzle tip  151   a  in the second liquid droplet nozzle  151  is several hundred nanometers or more and 20 μm or less, preferably 1 μm or more and 15 μm or less, more preferably 5 μm or more and 12 μm or less. 
     The second liquid droplet nozzle  151  has a glass tube, and an electrode  155  is provided inside the glass tube. In this example, a fine wire formed of tungsten is used as the electrode  155 . The electrode  155  is not limited to tungsten, and nickel, molybdenum, titanium, gold, silver, copper, platinum, or the like may be provided. 
     The electrode  155  in the second liquid droplet nozzle  151  is electrically connected to the power supply unit  120 . The second liquid held in the second ink tank  153  is ejected as a second liquid droplet  157  (see  FIG. 5 ) from the nozzle tip  151   a  (also referred to as a second tip) of the second liquid droplet nozzle  151  by voltages (in this example, 1000V) applied from the power supply unit  120  to the inside of the second liquid droplet nozzle  151  and the electrode  155 . By controlling the voltage applied from the power supply unit  120 , the shapes of the liquid droplet (patterns) formed by the second liquid droplet  157  can be controlled. 
     The first liquid droplet ejection unit  140  and the second liquid droplet ejection unit  150  are arranged along a direction in which the first liquid droplet ejection unit  140  and the second liquid droplet ejection unit  150  move relative to the object holding unit  160  (in this example, the direction D 1 ). Specifically, the first liquid droplet ejection unit  140  (specifically, the nozzle tip  141   a  of the first liquid droplet nozzle  141 ) is arranged in front of the second liquid droplet ejection unit  150  (specifically, the nozzle tip  151   a  of the second liquid droplet nozzle  151 ) with respect to the directions in which the first liquid droplet ejection unit  140  and the second liquid droplet ejection unit  150  move. The distances L between the first liquid droplet ejection unit  140  and the second liquid droplet ejection unit  150  can be appropriately adjusted. 
     The object holding unit  160  has a function of holding the object  200 . For the object holding unit  160 , a stage is used in this instance. The mechanism by which the object holding unit  160  holds the object  200  is not particularly limited, and a common holding mechanism is used. In this example, the object  200  is vacuum-adsorbed to the object holding unit  160 . In addition, it is not limited thereto, the object holding unit  160  may hold the object  200  using a fixture. 
     [1-2. Liquid Droplet Ejection Method] 
     Next, a liquid droplet ejection method is described with reference to the drawings. 
     First, the first liquid droplet ejection unit  140  and the second control unit  150  move onto the object  200  prepared in the liquid droplet ejection device  100  by the control unit  110  and the driving unit  130 . At this time, as shown in  FIG. 2 , the first liquid droplet ejection unit  140  is arranged on the first region R 1  of the object  200  at a certain distance from the surface of the first region R 1 . 
     The object  200  refers to a member in which the first liquid droplet  147  and the second liquid droplet  157  are ejected. In this embodiment, a flat glass plate is used for the object  200 . The object  200  is not limited to the flat glass plate. For example, the object  200  may be a metallic plate or an organic member. The object  200  may include a counter electrode for the liquid droplet ejection. 
     Next, as shown in  FIG. 3 , the first liquid droplet ejection unit  140  ejects the first liquid droplet  147  to the first region R 1 . 
     Surface treatment liquid is used for the first liquid droplet  147 . It is desirable that the surface treatment liquid is highly wettable with respect to the object  200 . It is desirable that the surface treatment liquid remains on the object  200  in a certain period of time after being ejected. Specifically, it is desirable that the surface treatment liquid has a high boiling point and a low vapor pressure property. It is desirable that the surface treatment liquid has conductivity (10 6 Ω/sq or more and 10 11 Ω/sq or less) to the extent that static electricity can be removed. Thus, it is possible to have a charge removing effect on the surface of the object  200 . In addition, it is desirable that the surface treatment liquid does not leave solids or the like after volatilization. 
     In this example, a volatile material is used for the first liquid droplet  147 . Specifically, a mixed liquid of ethanol and water is used for the first liquid droplet  147 . By using the first liquid droplet  147 , the surface of the object  200  can be appropriately neutralized, and the wettability for the surface of the object  200  can be improved. 
     The first liquid droplet  147  may include various kinds of alcohols, a mixed solution of the various kinds of alcohols and water, or a ketone and ether-based organic solvents with volatile properties other than alcohol in addition to water, ethanol, and a mixture of ethanol and water as a volatile material. 
     The ejection amount of the first liquid droplet  147  is not particularly limited, but is preferably such that the wettability in the object  200  can be improved and the charge on the surface of the object  200  can be removed. Specifically, in the case of a mixed liquid in which ethanol and water are mixed at 1:1, it is preferable that a coating amount per 1 square centimeters is 0.01 μl or more and 1 μl or less as. In this case, thickness of the formed first liquid droplet  147  is 0.1 μm or more and 10 μm or less. 
     The region in which the first liquid droplet  147  is ejected is desirably larger than size of the pattern formed by the second liquid droplet  157 . This allows the second liquid droplet  157  to adhere more stably to the object  200 . 
     Next, as shown in  FIG. 4 , the first liquid droplet ejection unit  140  moves from the first region R 1  to a second region R 2  on the object  200 . The second liquid droplet ejection unit  150  moves onto the first region R 1  on which the first liquid droplet  147  is ejected, in accordance with the movement of the first liquid droplet ejection unit  140 . The moving speeds of the first liquid droplet ejection unit  140  and the second liquid droplet ejection unit  150  are desirably set in advance to such an extent that the wettability on the subject can be maintained considering an elapsed time after the first liquid droplet  147  is ejected, an drying speed of the first liquid droplet  147 , a distance between the first liquid droplet ejection unit  140  and the second liquid droplet ejection unit  150 , and the like. In this case, it can be said that the first liquid droplet ejection unit  140  and the second liquid droplet ejection unit  150  move in the direction D 1 . 
     Next, as shown in  FIG. 5 , the first liquid droplet ejection unit  140  ejects the first liquid droplet  147  onto the second region R 2  on the object  200  in the same manner as the first region R 1 . The second liquid droplet ejection unit  150  ejects the second liquid droplet  157  onto the first region R 1  in synchronization with the first liquid droplet ejection unit  140 . In this example, the second liquid droplet ejection unit  150  ejects the second liquid droplet  157  at the same time as the first liquid droplet ejection unit  140  ejects the first liquid droplet  147 . 
     A material with a higher viscosity than the first liquid droplet  147  is used for the second liquid droplet  157 . Specifically, an ink (also referred to as a second liquid) for forming a pattern containing a pigment is used for the second liquid droplet  157 . The second liquid droplet  157  may include a conductive grain. The second liquid droplet ejection unit  150  includes an electrostatic ejection type inkjet, and the ejection amount of the second liquid droplet  157  is controlled by a voltage applied from the power supply unit  120 . It is desirable that the ejection amount of the second liquid droplet  157  is 0.1 fl or more and 100 μpl or less. The pattern size in the present embodiment is 100 nm or more and 500 μm or less. 
     The first region R 1  in which the second liquid droplet  157  is ejected is in a state in which the first liquid droplet  147  is volatilized, and does not remain or remains slightly on the surface of the object. In this case, the surface of the first region R 1  is electrostatically discharged and have good wettability (lyophilic). Thus, when the second liquid droplet  157  is ejected onto the first region R 1 , it is possible to have good adhesion to the surface of the object  200 . Therefore, the second liquid droplet  157  is disposed at a predetermined position. 
     The first liquid droplet ejection unit  140  and the second liquid droplet ejection unit  150  repeat the above processes to perform the desired liquid droplet ejection.  FIG. 6  is a top view of the object  200  after the liquid droplet ejection. As shown in  FIG. 6 , the pattern (second liquid droplet  157 ) is disposed at a desired position on the object  200 . In this case, the first liquid droplet  147  may be volatilized or may remain partially. 
     Here, comparing the present disclosure with the prior art, in the prior art, a plasma treatment or a UV ozone treatment has been used to eliminate static electricity on the surface of the object  200 . However, by using this embodiment, the second liquid droplet  157  can be stably deposited at a predetermined position on the surface of the object  200 . In other words, the liquid droplets can be easily and stably ejected onto the surfaces of the object  200 . By using this embodiment, it is not necessary to perform the plasma treatment, so that the damage to object can be reduced. 
     Second Embodiment 
     In the present embodiment, examples in which a step  170  is provided on the surface of the object  200  is described with reference to the drawings. 
     First, as shown in  FIG. 7 , the first liquid droplet ejection unit  140  and the second liquid droplet ejection unit  150  are moved and disposed on the object  200  having the step  170 . The step  170  (also referred to as a pattern or convex part) on the surface of the object  200  is provided as an organic insulating layer. The organic insulating layer used for the step  170  is not particularly limited. In this example, a polyimide resin is used for the step  170 . The organic insulating layer may be formed of other organic resin such as an acrylic resin or an epoxy resin, or an inorganic material. In this embodiment, the step  170  is provided in the shape of a grid (also referred to as a parallel cross structure) so as to expose a part of the surface on the object  200 . Each of the first region R 1  and the second region R 2  is surrounded by the step  170 . 
     In this case, the first liquid droplet ejection unit  140  is arranged on the first region R 1 . The first liquid droplet ejection unit  140  ejects the first liquid droplet  147  onto the first region R 1  (more specifically, at a predetermined position within the first region R 1 ). As shown in  FIG. 8 , the first liquid droplets  147  are ejected onto the surfaces of the step  170  and the object  200 . 
     Next, the first liquid droplet ejection unit  140  moves from the first region R 1  to the second region R 2  on the object  200 . The second liquid droplet ejection unit  150  moves onto the first region R 1  where the first liquid droplet  147  was ejected. In this case, the first liquid droplet  147  attempts to minimize the surface area by surface tension. When there is a region surrounded by such a parallel cross structure, the first liquid droplet  147  attempts to minimize the area of the interface with the air by retracting into the region. Further, the evaporation rate of the first liquid droplet  147  is faster as the thickness of the first liquid droplet  147  is thinner. Therefore, the first liquid droplet  147  of the region (inside of the parallel cross structure) surrounded by the step evaporates slowly, and the liquid on the step  170  dries quickly. Therefore, as shown in  FIG. 9 , after a predetermined period of time has elapsed, the first liquid droplet  147  exists only in the region (inside of the parallel cross structure) surrounded by the step  170 . The first liquid droplet  147  is repelled from the step  170  in the first region R 1  and remains only on the object  200 . 
     Similar to the first region R 1 , the first liquid droplet ejection unit  140  ejects the first liquid droplet  147  onto the second region R 2  of the object  200 . The second liquid droplet ejection unit  150  ejects the second liquid droplet  157  onto the first region R 1  in synchronized with the first liquid droplet ejection unit  140 . In this example, the second liquid droplet ejection unit  150  ejects the second liquid droplet at the same time as the first liquid droplet ejection unit  140  ejects the first liquid droplet. In this case, the second liquid droplet  157  may be ejected in the situation in which the first liquid droplet  147  remains on the surface of the first region R 1  in the object  200 . 
     The first liquid droplet ejection unit  140  and the second liquid droplet ejection unit  150  repeat the above-described process. As shown in  FIG. 10 , the second droplets  157  are ejected not on the step  170 , but only on the surface of the object  200 . 
     In the present embodiment, when the second liquid droplet  157  is ejected, the first liquid droplet  147  remains only on the surface (specifically, inside the parallel cross structure) of the object  200 . This suppresses electrostatic charging on the object  200  and improves the wettability on the surface of the object  200 . Therefore, the second liquid droplet  157  is easily landed on the surface of the object  200  preferentially, and the second liquid droplet  157  can be stably ejected without being affected by the step  170 . 
     Also, when there is the first liquid droplet  147  having the conductive inside of the parallel cross structure, an electric field line is concentrated in the portion. This makes it easier for the second liquid droplet  157  (ink) to land on the inside of the parallel cross structure. That is, the second liquid droplet  157  can be ejected to a desired position. 
     From the above, by using the present embodiment, the electrostatic charging of the object itself is removed, and the effect of the step  170  applied to the object is alleviated. Thus, as shown in  FIG. 11 , in the case in which the step  170  is provided on the surface of object  200 , the second liquid droplet  157  can be stably ejected and desired patterns can be formed. The first liquid droplet  147  may remain on the object  200  after patterning by the second liquid droplet  157 . 
     Third Embodiment 
     In the present embodiment, a liquid droplet ejection device differing from the first embodiment is described. Specifically, an example in which a liquid droplet ejection device includes a plurality of first liquid droplet nozzles  141  and a plurality of second liquid droplet nozzles  151  will be described. For the sake of explanation, members thereof is omitted as appropriate. 
     [3-1. Configuration of the Liquid Droplet Ejection Device  100 ] 
       FIG. 12  is a schematic view of a liquid droplet ejection device  100 A according to an embodiment of the present disclosure. The liquid droplet ejection device  100 A includes the control unit  110 , the storage unit  115 , the power supply unit  120 , the driving unit  130 , a first liquid droplet ejection unit  140 A, and a second liquid droplet ejection unit  150 A. 
     In the present embodiment, a plurality of first liquid droplet ejection unit  140 A are provided in direction (specifically, D 3  direction orthogonal to the D 1  direction) intersecting with respect to the direction (in this case, the D 1  direction) in which the first liquid droplet ejection unit  140 A moves (specifically, the first liquid droplet ejection unit  140 A includes a first liquid droplet nozzle  141 A- 1 ,  141 A- 2 ,  141 A- 3 , and  141 A- 4 , each arranged independently). Similarly, a plurality of second liquid droplet ejection unit  150 A are provided in direction intersecting with respect to the direction in which the first liquid droplet ejection unit  140 A and the second liquid droplet ejection unit  150 A move (more specifically, the second liquid droplet ejection unit  150 A includes a second liquid droplet nozzle  151 A- 1 ,  151 A- 2 ,  151 A- 3 , and  151 A- 4 , each arranged independently). In the present embodiment, by having the first liquid droplet ejection unit  140 A and the second liquid droplet ejection unit  150 A, the process duration of the liquid droplet ejection can be shortened. 
     In the present embodiment, an example in which the plurality of first liquid droplet ejection unit  140 A is shown, but the present disclosure is not limited thereto. The first liquid droplet ejection unit  140 A does not need to have a precise positional accuracy, and thus may have different shape. 
       FIG. 13  is a schematic view of a liquid droplet ejection device  100 B according to an embodiment of the present disclosure. In the liquid droplet ejection device  100 B, a first liquid droplet nozzle  141 B in a first liquid droplet ejection unit  140 B may extend in a direction (specifically D 3  direction) intersecting the direction in which the first liquid droplet ejection unit  140 B moves (in this case D 1  direction). Specifically, as shown in  FIG. 13 , the first liquid droplet nozzle  141  may have a slit-shape. In this instance, the first liquid droplets  147  are ejected from the first liquid droplet nozzle  141  in a row. In this case, in the top view of patterns to be formed, as shown in  FIG. 14 , the first liquid droplets  147  may be provided in a row, and the second liquid droplets  157  may be provided at predetermined positions apart from each other. 
     In the present embodiment, an example in which a plurality of second liquid droplet nozzle  151 A are independently each provided in the second liquid droplet ejection unit  150  A is shown, but the present disclosure is not limited thereto.  FIG. 15  is a top view of a second liquid droplet nozzle  151 C.  FIG. 16A  is an enlarged top view of a part in the second liquid droplet nozzle  151 C.  FIG. 16B  is a cross-sectional view of a part in the second liquid droplet nozzle  151 C. As shown in  FIGS. 15 and 16 , the second liquid droplet nozzle  151 C has a plurality of nozzle units  151 Cb and plate units  151 Cc. In this example, a plurality of nozzle units  151 Cb are arranged in a row but may be arranged in a plurality of rows. 
     A metal material such as nickel is used for the nozzle unit  151 Cb. The nozzle unit  151 Cb is formed to be tapered by, for example, an electroforming process. A metal material such as stainless steel is used for the plate unit  151 Cc. The plate unit  151 Cc has a hole having an inner diameter r 151 Cc larger than the inner diameter r 151 Ca of the ejection port (nozzle tip  151 Ca) in the nozzle unit  151 Cb in a portion overlapping with the nozzle unit  151 Cb. The nozzle unit  151 Cb may be welded to the plate unit  151 Cc or may be fixed by an adhesive. When the second liquid droplet nozzle  151 C is used, a voltage may be applied to the nozzle  151 Cb, or a voltage may be applied to the plate unit  151 Cc (or the second ink tank  153 ). 
     A person of ordinary skill in the art would readily conceive various alterations or modifications of the present disclosure, and such alterations and modifications are construed as being encompassed in the scope of the present disclosure. For example, the devices in the above-described embodiments may have an element added thereto, or deleted therefrom, or may be changed in design optionally by a person of ordinary skill in the art. The methods in the above-described embodiments may have a step added thereto, or deleted therefrom, or may be changed in the condition optionally by a person of ordinary skill in the art. Such devices and methods are encompassed in the scope of the present disclosure as long as including the gist of the present disclosure. 
     [Modification] 
     In the first embodiment of the present disclosure, an example in which the first liquid droplet ejection unit  140  and the second liquid droplet ejection unit  150  move on the object  200  by the driving unit  130  is shown, but the present disclosure is not limited thereto. For example, in the liquid droplet ejection device, the driving unit  130  may move the object  200 . In this instance, the first liquid droplet ejection unit  140  and the second liquid droplet ejection unit  150  may be fixed in the same position. 
     In the first embodiment, the piezo type inkjet nozzle is used for the first liquid droplet nozzle  141  of the first liquid droplet ejection unit  140 , but the present disclosure is not limited thereto. A spraying nozzle may be used for the first liquid droplet ejection unit  140 . When the spray nozzle is used, the first liquid droplet  147  can be ejected or sprayed over a wide area of the object  200 . 
     In the first embodiment of the present disclosure, an example in which the first liquid droplet nozzle  141  is provided perpendicularly to the surface of the object  200  is shown, but the present disclosure is not limited thereto. The first liquid droplet nozzle  141  may have an inclination with respect to the direction perpendicular to the object  200 . The same applies to the second liquid droplet nozzle  151  of the second liquid droplet ejection unit  150 . 
     In the first embodiment of the present disclosure, an example has been shown in which a material having volatility is used for the first liquid droplet  147 , but the present disclosure is not limited thereto. For example, an antistatic agent may be used for the first liquid droplet  147 . In this case, it is desirable that the surface resistance value of the first liquid droplet  147  is 10 6 Ω/sq or more and 10 11 Ω/sq or less. The antistatic agent may not have volatility and may remain partially on the surface of the object  200   
     In the first embodiment of the present disclosure, an example in which the organic insulating layer is used as a step is shown, but the present disclosure is not limited thereto. For example, the step may be a wiring pattern, or an inorganic material may be used as the step. The object  200  itself may be processed to provide a step. The object  200  may be a wiring substrate in which wiring is laminated. 
     When the second liquid droplet  157  is ejected in the first embodiment of the present disclosure, an image may be taken by using an imaging device. In this instance, the imaging result may be determined by the control unit  110 . When the control unit  110  determines that there is an ejection failure, the control unit  110  may eject the first liquid droplet  147  and the second liquid droplet  157  again on the failure occurrence region. As a result, it is possible to suppress the liquid droplet ejection failure. 
     In the first embodiment of the present disclosure, an example has been described in which the first liquid droplet and the second liquid droplet are simultaneously ejected when the first liquid droplet and the second liquid droplet are synchronously ejected, but the present disclosure is not limited thereto. For example, the first liquid droplet and the second liquid droplet may not be ejected simultaneously, but the second liquid droplet may be ejected after the first liquid droplet has been ejected and a predetermined period of time elapsed. The first liquid droplet and the second liquid droplet may be ejected in conjunction with each other.