Patent Publication Number: US-2015075425-A1

Title: Coating System Using Spray Nozzle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority under 35 U.S.C. §119(a) of Korean Patent Application No. 10-2013-0110716, filed on Sep. 13, 2013, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes. 
     BACKGROUND 
     1. Field 
     The following description relates to a coating system using a spray nozzle, and more particularly to a spray nozzle capable of effectively coating a substrate through droplets of a uniform size and applicable to mass production processes, and a coating system thereof. 
     2. Description of Related Art 
     A coating process is essential in not only traditional industrial areas such as automobile and construction, but also in manufacturing areas such as display and solar cell etc. Especially, when manufacturing displays such as organic solar cells and organic light emitting diodes (OLED) etc., there is required a precise coating of a thickness of tens to hundreds nanometers. In addition, since the roughness and uniformity of a coating surface have a significant effect on the performance of a product, it should be possible to use ultrafine droplets, and to coat the product quickly for mass production. 
     Recently, as application of touch screens increases, anti-fingerprint coating or anti-reflecting coating method for application on the surfaces of touch window surfaces such as smart phones, tablets, notebook computers etc. are being converted into wet coating processes instead of conventional vacuum coating processes. 
     The technology of atomizing liquid for conventional spray coating processes may be broadly classified into methods using pressure energy, gas energy, centrifugal energy, mechanical energy, and electrical energy. 
     Herein, the method of using pressure energy is a method of using pressure injection valves, wherein the liquid to be atomized is passed through single hole or porous injection nozzles, or vortex injection valves (simplex, duplex, dual orifice, and reflux types etc.) to form spray. This is a method generally used to spray liquid fuel injected into a gas turbine burner, randomly creating droplets of approximately 20˜250 μm. Therefore, in such a method of using pressure energy, there is a problem that it is difficult to be applied to a complicated coating technology. 
     In addition, the method that uses centrifugal energy utilizing a wheel atomizer or rotary cup atomizer is a method of randomly creating droplets of a range of 10˜200 μm. It is a method mainly used in cleaning and agriculture areas. In this method, it is impossible to coat the central portion, and thus there is a problem that it is difficult to be applied to a uniform coating technology. 
     Meanwhile, there is a gas bombardment atomizer method which is method of using gas energy, wherein a great quantity of gas in a low speed and low pressure state is injected towards a jet of liquid that is being injected using a two-fluid injection valve to atomize the liquid, and a gas assisted atomizer method wherein a small amount of gas in a high speed state is injected towards a liquid jet. This method is mainly used in thin film wet coating, but in this method, the droplets would be formed to have a random size between 15˜200 μm, thus making it difficult to form a fine thin film coating, and stains may occur on the coating surface, and further, due to the high fluid speed when injecting the gas at a high speed, the fast fluid speed may make the atomized droplets collide with the substrate, causing the droplets to bounce back. In addition, there may be too much coating liquid coming off the substrate, causing a waste of the coating liquid, thereby increasing manufacturing costs, and since the viscosity of the liquid that can be used is limited to less than 50 cp, there may be limitations in the coating technology in developing or applying functional materials, causing difficulty in developing various types of coating technologies. 
     Furthermore, the most representative method of using mechanical energy is the ultrasound spray technology wherein liquid is atomized by high frequency signals applied by a piezoelectric actuator. In this method, droplets may be further atomized than when using gas energy, but droplets are formed to have a random size between 1˜200 μm, making it difficult to secure uniformity in the size of droplets, and there is also a limitation in the amount of injection of droplets, thereby causing a problem of difficulty in utilizing in mass production processes. 
     Meanwhile, as a method of using electrical energy, there is the electrospray method wherein droplets are drawn towards a strong electric field and then atomized. An advantage of this method is that it is possible to produce fine and uniform droplets having a size range of hundreds nm to 5 μm. However, there are limitations that there needs to be at least 10 −4  S/m of electrical conductivity, and that the amount of liquid sprayed is limited to 10 −10  to 10 −9  m 3 /sec, thereby making it difficult to be applied to mass product processes. 
     Furthermore, there occurs a problem where according the features of the droplets being sprayed towards a substrate and the conditions of the substrate, the droplets being sprayed may not be shot to the substrate uniformly. 
     SUMMARY 
     Therefore, the purpose of the present disclosure is to resolve the aforementioned problems of prior art, that is to provide a coating system using a spray nozzle capable of controlling the size of droplets to be fine and uniform so as to coat a substrate effectively, and applicable to mass production processes. 
     In a general aspect, there is provided a coating system using a spray nozzle, the coating system comprising: a support where a substrate is disposed; a spray nozzle injecting liquid that has gone through a primary atomization by collision with gas, towards the substrate; a voltage applier applying voltage to the spray nozzle so that the liquid injected from the spray nozzle includes electric charge, and generating an electric field between the support and the spray nozzle by the voltage applied to the spray nozzle and performing a secondary atomization of the liquid injected from the spray nozzle; and a transferrer transferring at least one of the support and the spray nozzle. 
     In the general aspect of the coating system, it is desirable that the support is made of conductive material. 
     In the general aspect of the coating system, it is desirable that the support is provided with a coating layer of non-conductive material on an external surface thereof. 
     In the general aspect of the coating system, it is desirable that the support receives voltage or is grounded selectively depending on its location. 
     In the general aspect of the coating system, it is desirable that the coating system further comprises a plasma processor configured to plasma process the substrate; and that the spray nozzle is provided with a substrate plasma processed through the plasma processor. 
     In the general aspect of the coating system, it is desirable that the plasma processor cleans a surface of the substrate, or processes the surface of the substrate to be hydrophilic or hydrophobic depending on the liquid injected from the spray nozzle. 
     In the general aspect of the coating system, it is desirable that the plasma processor performs at least one of charging and discharging the substrate, and the spray nozzle is spaced by 500 mm or less from the plasma processor along a transferring path of the substrate. 
     In the general aspect of the coating system, it is desirable that the transferrer comprises a first transferrer configured to transfer the support; and a second transferrer configured to move the spray nozzle in a direction approaching or distancing from the support. 
     In the general aspect of the coating system, it is desirable that the coating system further comprises a container accommodating a spray nozzle inside thereof, the container comprising an inlet and outlet for entering/exiting of the substrate. 
     In the general aspect of the coating system, it is desirable that the the container is provided with a gas channel for injecting nitrogen or inert gas inside thereof or discharging the nitrogen or inert gas. 
     In the general aspect of the coating system, it is desirable that at least one of a certain gas concentration, temperature and humidity is maintained inside the container. 
     In the general aspect of the coating system, it is desirable that the coating system further comprises a sensor configured to obtain location information of the support; and a controller configured to receive the location information of the support through the sensor and control operations of at least one of the plasma processor, spray nozzle, voltage applier and transferrer. 
     In the general aspect of the coating system, it is desirable that the controller comprises: an electric field control module configured to control an intensity of an electric field formed between the spray nozzle and the support by adjusting a voltage amount applied to the spray nozzle; a pressure control module configured to control a pressure of the gas that collides with the liquid in the spray nozzle; a transfer control module configured to control a movement of the transferrer; and a flow rate control module configured to control a flow rate of the liquid injected form the spray nozzle. 
     In the general aspect of the coating system, it is desirable that the spray nozzle comprises: a liquid injector configured to inject liquid; and a gas injector configured to have the gas collide with ink on an injection path of the liquid so that a primary atomization is performed of the liquid. 
     In the general aspect of the coating system, it is desirable that the gas vertically collides with a movement path of the ink. 
     In the general aspect of the coating system, it is desirable that the spray nozzle further comprises a case accommodating the liquid injector and the gas injector inside thereof, and a gas path configured to guide a flow direction of the gas so that the gas injected from the gas injector collides with the liquid on the injection path of the gas. 
     According to the present disclosure, there is provided a coating system using a spray nozzle capable of coating a surface of a substrate uniformly according to the present disclosure. 
     In addition, it is possible to apply a process of coating a substrate to mass production processes. 
     In addition, it is possible to improve a substrate shooting rate of droplets by plasma processing a surface of the substrate according to features of droplets to be coated on the surface of the substrate. 
     In addition, it is possible to divide a precoated area and an area not coated prior to performing a coating process by plasma processing the area to be coated, in consideration of features of droplets coated on a surface of a substrate. 
     In addition, it is possible to easily shoot droplets injected from a spray nozzle by charging or discharging a surface of a substrate through a plasma processing. 
     In addition, it is possible to easily adjust conditions for coating a substrate by closing a spray nozzle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Throughout the drawings and the detailed description, unless otherwise described, the same drawing reference numerals will be understood to refer to the same elements, features, and structures. The relative size and depiction of these elements may be exaggerated for clarity, illustrating, and convenience. 
         FIG. 1  is a schematic skewed view of a coating system using a spray nozzle according to an exemplary embodiment of the present disclosure. 
         FIG. 2  is a schematic skewed view of inside a container in a coating system using a spray nozzle according to  FIG. 1 . 
         FIG. 3  is a schematic cross-sectional view of two types of spray nozzle used in a coating system using a spray nozzle according to  FIG. 1 . 
         FIG. 4  is a schematic conceptual view of a controller in a coating system using a spray nozzle according to  FIG. 1 . 
         FIG. 5  is a schematic plane view of inside a container in a coating system using a spray nozzle according to  FIG. 1 . 
         FIG. 6  is a schematic view of a substrate plasma processed by a plasma processor in a coating system using a spray nozzle according to  FIG. 1 . 
         FIG. 7  is a schematic skewed view of coating a plasma processed substrate through a spray nozzle in a coating system using a spray nozzle according to  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses, and/or systems described herein. Accordingly, various changes, modifications, and equivalents of the systems, apparatuses and/or methods described herein will be suggested to those of ordinary skill in the art. Also, descriptions of well-known functions and constructions may be omitted for increased clarity and conciseness. 
       FIG. 1  is a schematic skewed view of a coating system using a spray nozzle according to an exemplary embodiment of the present disclosure, and  FIG. 2  is a schematic skewed view of inside a container in a coating system using a spray nozzle according to  FIG. 1 . 
     With reference to  FIG. 1  or  FIG. 2 , a coating system using a spray nozzle according to an exemplary embodiment of the present disclosure is capable of coating a substrate with uniformly atomized droplets and improving a substrate shooting rate of atomized droplets by plasma processing a surface of the substrate prior to coating the substrate. Herein, the coating system using a spray nozzle comprises a support  110 , plasma processor  120 , spray nozzle  130 , voltage applier  140 , transferrer  150 , container  160 , sensor  170 , and controller  180 . 
     The support  110  is where a substrate S is disposed, the support  110  being provided by a flat panel type material. In an exemplary embodiment of the present disclosure, the support  110  is moveable through a first transferrer  151  that will be explained hereinafter, and guides a movement of the substrate S so as to sequentially process a plasma processing and coating process. 
     Meanwhile, the support  110  according to an exemplary embodiment of the present disclosure receives voltage or is grounded according to each process of processing the substrate, and for this purpose, the support  110  is provided by a conductive material. 
     In addition, in order to prevent direct affect on the substrate S, an outer surface that contacts the substrate S is preferably provided with a coating layer  111  of nonconductive material. 
     Meanwhile, according to an exemplary embodiment of the present disclosure, in an example of voltage being applied to the support  110 , as a polarity other than the polarity of plasma is applied to the support  110 , the plasma may move towards the substrate S when a surface of the substrate S is plasma processed as it passes the plasma processor  120 . 
     In addition, in an example of the support  110  being grounded, the support  110  is grounded so that plasma is stably formed when a surface of the substrate S is plasma processed as it passes the plasma processor  120 . 
     Furthermore, in another example of the support  110  being grounded, a potential difference may be generated between a spray nozzle  130  and a support  110  so as to form a strong electric field between the spray nozzle  130  and the support  110  when the substrate S is coated as it passes the spray nozzle  130 . 
     Of course, there is no limitation to the aforementioned, and thus if necessary, voltage may be applied to the support  110  or the support  110  may be grounded. 
     The plasma processor  120  is configured to plasma process an outer surface of the substrate S being transferred through a first transferrer  151  that will be explained hereinafter. 
     According to an exemplary embodiment of the present disclosure, the plasma processor  120  may clean a coated surface of the substrate S, or process the surface of the substrate S to be coated to be hydrophilic or hydrophobic. 
     Herein, the hydrophilic or hydrophobic features are determined in consideration of the liquid used in a spray nozzle  130  that will be explained hereinafter. 
     That is, if the liquid used in the spray nozzle  130  is hydrophilic, an outer surface of the substrate S is plasma processed to be hydrophilic so that the liquid can be effectively shot to the outer surface of the substrate S. On the contrary, if the liquid used in the spray nozzle  130  is hydrophobic, the outer surface of the substrate S is plasma processed to be hydrophobic. 
     Furthermore, a portion of the substrate S may be processed to be hydrophilic while the remaining portion of the substrate S is processed to be hydrophobic. That is, in a case of coating an outer surface of the substrate S to have a certain pattern, a certain area of an outer surface of the substrate S may be plasma processed to have same features as the liquid, while the remaining area besides the certain area of the outer surface of the substrate S is plasma processed to have different features from the liquid, thereby coating the substrate such that the liquid is concentrated on the certain area. 
     In addition, in an exemplary embodiment of the present disclosure, the plasma processor  120  may perform a process of charging or discharging the substrate S. Herein, a discharging of the substrate S is performed when charges on the substrate S are distributed non-uniformly, whereas a charging of the substrate S is performed when charges on the substrate S are distributed uniformly. 
     That is, by discharging or charging the substrate S through the plasma processor  120 , it is possible to shoot atomized droplets from the spray nozzle  130  that will be explained hereinafter even more effectively. 
     Meanwhile, as aforementioned, in the present exemplary embodiment of the present disclosure, the substrate S is processed to be hydrophilic or hydrophobic or discharged or charged through the plasma processor  120 , but without limitation. 
     In addition, in an exemplary embodiment of the present disclosure, the plasma processor  120  may be an atmospheric-pressure plasma, but without limitation. 
       FIG. 3  is a schematic cross-sectional view of two types of spray nozzle used in a coating system using a spray nozzle according to  FIG. 1 . 
     With reference to  FIG. 3 , the spray nozzle  130  receives the substrate S plasma processed through the aforementioned plasma processor  120 , and injects towards the substrate the droplets that have gone through primary atomization by colliding with gas. Herein, the spray nozzle  130  comprises a liquid injector  131  and gas injector  132 . 
     The liquid injector  131  is a path where ink flows, and it also injects the ink towards the plasma processed substrate S. 
     The gas injector  132  is configured to inject gas, and the gas injected from the gas injector  132  vertically collides with an injection path of the ink, thereby performing a primary atomization of the liquid. 
     Herein, for a primary atomization of the ink, collision of the gas and ink is a very important factor, and in order to stably atomize the ink, the gas must collide vertically with the injection path of the ink. 
     That is, if the gas fails to vertically collide with the injection path of the ink, the gas may have an effect in the injection direction of the ink or in the opposition direction thereof. When collision of the gas and ink applies a force in the injection direction of the ink, the atomized ink may collide with the substrate S at an excessive speed thereby causing the ink to rebound. And when collision of the gas and ink applies a force in the opposite direction of the injection direction of the ink, the injection of the ink may be interrupted by the gas, thereby having a negative effect on the injection speed or injection flow rate of the ink. 
     Therefore, in order to prevent these problems, it is preferable without limitation that the gas vertically collides with the injection path of the ink, but these problems may be resolved instead by adjusting the injection speed of the ink. 
     Meanwhile, as illustrated in  FIG. 3(   a ), the liquid injected through the liquid injector  131  and the gas injected through the gas injector  132  may collide with each other in an area between the spray nozzle  130  and the support  110 . 
     In such a case, in order to minimize the effect of other factors when the liquid collides with the gas, it is desirable that an area that is coated by the spray nozzle  130  is provided with an additional chamber and be closed. 
     In addition, it is desirable that there is further provided a case  133  that accommodates a liquid injector  131  and gas injector  132  inside thereof so that the collision of the liquid and the gas can be made in a sealed space as illustrated in  FIG. 3(   b ), thereby the spray nozzle  130  injecting liquid that has been almost atomized or preferably completely atomized. 
     Herein, inside the case, there may be further provided without limitation a gas path  134  where the gas injected from the gas injector  132  flows and that guides the flowing direction of the gas so that the gas vertically collides with the injection path of the liquid. 
     The voltage applier  140  applies voltage to the spray nozzle  130  so that the liquid injected from the spray nozzle  130  can include electric charge, and creates an electric field between the spray nozzle  130  and the support  110  by the voltage applied to the spray nozzle to perform a secondary atomization of the liquid injected from the spray nozzle  130  through the electric field. 
     Meanwhile, in an exemplary embodiment of the present disclosure, the spray nozzle  130  is situated, without limitation, to be close to the plasma processor  120 , and the spray nozzle  130  and the plasma processor  120  are spaced from each other by a distance of 500 mm or below so that the liquid having electric charge when the substrate S is charged or discharged through the plasma processor  120  can be easily shot to the substrate S. 
     That is, it is desirable that the spray nozzle  130  and the plasma processor  120  are close to each other so as to prevent the electric charge on the charged or discharged substrate S dissipating before the liquid is shot to the substrate S, and in an exemplary embodiment of the present disclosure, the spray nozzle  130  and the plasma processor  120  are spaced from each other by 500 mm or below. 
     Meanwhile, when voltage is applied to the liquid injector  131  through the voltage applier  140 , the liquid injected to the substrate S through the liquid injector  131  would include electric charge by the voltage applied from the voltage applier  140 , and a potential difference would be generated between the support  110  and the spray nozzle  130  thereby forming an electric field for performing a secondary atomization of the liquid that has gone through a primary atomization. 
     By sequentially atomizing liquid through collision with gas and through an electric field as aforementioned, it is possible to form fine droplets of a uniform size and inject a large amount of liquid. Furthermore, by guiding the atomized liquid to be injected towards the substrate S using the electric field, it is possible to prevent the droplets from rebounding and reduce the amount of consumption of the material. 
     The transferrer  150  transfers at least one of the aforementioned support  110  and spray nozzle  130 . The transferrer  150  comprises a first transferrer  151  configured to transfer the support  110  and a second transferrer  155  configured to transfer the spray nozzle  130 . 
     The first transferrer  151  transfers the support  110 , and in an exemplary embodiment of the present disclosure, the first transferrer  151  comprises a rail  152  and an electrode  153 . 
     The rail  152  consists of a pair of rail members facing each other. The support  110  is mounted onto an upper side of the rail members so that the support  110  can slide along the rail  152 . 
     In addition, besides transferring the support  110  along the rail  152 , the first transferrer  151  may be provided, but without limitation, such that it rotates the support  110  on the upper side of the rail  152  or transfer the support  110  on a virtual plane that is parallel to the support  110 . 
     The electrode  153  is provided between the pair of  152 . In response to reaching a certain position of the support  110 , the electrode  153  contacts the support  110  and applies voltage to the support or grounds the support  110 . 
     Herein, the electrode  153  has a shape of a roll, a portion of the roll being provided with voltage while the remaining portion being grounded. By rotation, the electrode  153  selectively applies voltage to the support  110  or grounds the support  110 . 
     Meanwhile, the electrode  153  may have a shape of a spring, which applies voltage to the support  110  or grounds the support  110  as it contacts or is distanced from the support  110  by elasticity. 
     The second transferrer  155  is connected to the spray nozzle  130  to transfer the spray nozzle  130  in a direction either approaching or distancing from the support  110  or in a direction parallel to the support  110 . 
     That is, defining the directions parallel to the support  110  are x and y axis directions, and the direction approaching or distancing from the support  110  is z axis direction, the second transferrer  155  transfers the spray nozzle  130  in at least one direction of x, y, and z axis directions. 
     Meanwhile, the transferrer  150  may further comprise, without limitation, a third transferrer (not illustrated) configured to move the plasma processor  120  in a direction approaching or distancing from the support  110  or in a direction parallel to the support  110 . 
     The container  160  accommodates the plasma processor  120  and spray nozzle  130  inside thereof, and isolates the substrate S from outside during processing so as to maintain certain processing conditions. 
     In exemplary embodiment of the present disclosure, there is formed an inlet  161  to which the substrate S is provided and an outlet  162  to which the substrate S is output, and the first transferrer  151  is extended towards the inlet  161  and the outlet  162 . 
     In addition, the inlet  161  and the outlet  162  are provided such that they may be open/closed to close the inside of the container  160  during plasma processing and coating processing. 
     Furthermore, the container  160  may be provided with a gas channel  163  through which nitrogen or inert gas may be injected inside the container  160 . 
     Meanwhile, for an effective coating process, a certain gas concentration, humidity and temperature may be maintained, without limitation, inside the container  160 . 
     In other words, it is possible to measure the gas concentration, humidity and temperature inside the container  160 , and adjust the opening time etc. of the gas channel  163  to maintain the optimal gas concentration, humidity and temperature inside the container  160  based on the measurement results. 
     The sensor  170  measures location information of the support  110 . 
     In an exemplary embodiment of the present disclosure, the sensor  170  is provided in plural number, each spaced from one another along the rail  152 . The sensor  170  divides the location of the support  110  into an inlet section, a section being affected by the plasma processor  120 , a section being affected by the spray nozzle  130 , and an outlet section, and measures where the support  110  is located. 
       FIG. 4  is a schematic conceptual view of a controller in a coating system using a spray nozzle according to  FIG. 1 . 
     The controller  180  receives location information of the support  110  from the aforementioned sensor  170 , and controls operations of at least one of the plasma processor  120 , spray nozzle  130 , voltage applier  140  and transferrer  150 . The controller  180  comprises an electric field control module  181 , pressure control module  182 , transfer control module  183 , and flow rate control module  184 . 
     The electric field control module  181  adjusts the voltage applied to the liquid injector  131  through the voltage applier  140  to control the intensity of the electric field generated between the support  110  and the spray nozzle  130 . 
     As aforementioned, the intensity of the electric field is related to the secondary atomization of liquid, and thus it is possible to control the speed of the secondary atomization of liquid by adjusting the intensity of the electric field by the electric field control module  181 . 
     The pressure control module  182  adjusts the pressure of the gas supplied to the gas injector  132 . As aforementioned, the gas performs a primary atomization of liquid by colliding with the liquid being injected, and thus it is possible to control the primary atomization of the liquid by adjusting the pressure of the gas flowing along the gas injector  132 . 
     The transfer control module  183  controls the movement of the transferrer  150  so as to control the location and transferring speed of the support  110 , and the location and transferring speed of the spray nozzle  130 . 
     That is, the transfer control module  183  may control, without limitation, the first transferrer  151  so that the substrate S disposed on the support  110  performs a certain process, and may control, without limitation, the second transferrer  152  to change the initial injection location of the spray nozzle  130 . 
     The spray nozzle  130  may be transferred, without limitation, even when the liquid is being injected, and the transferring speed may be controlled, without limitation, such that it does not affect the injection state of the liquid. 
     The flow rate control module  184  controls the flow rate of the liquid injected from the spray nozzle  130  by adjusting the flow rate of the liquid supplied to the liquid injector  131 . 
     That is, the liquid density and diameter of the liquid injector  131  being the same, the injection speed of the liquid is proportionate to the mass flow rate or volumetric flow rate of the liquid, and thus it is possible to control the injection speed of the liquid by adjusting the mass flow rate or volumetric flow rate of the liquid. 
     Herein, the injection speed of the liquid affects the time it takes for the injected liquid to arrive at the substrate S, and if this time is significantly short, the liquid would arrive at the substrate S without having gone through a sufficient secondary atomization, thereby increasing the roughness and non-uniformity of the coating surface of the substrate S. Therefore, the injection speed is controlled by the flow rate control module  184 . 
     Hereinbelow is explanation on operations of an exemplary embodiment of a coating system using the aforementioned spray nozzle. 
       FIG. 5  is a schematic plane view of inside a container in a coating system using a spray nozzle according to  FIG. 1 . 
     Hereinbelow is explanation on operations of a coating system using a spray nozzle according to an exemplary embodiment of the present disclosure  100  based on the transferring direction of the substrate S with reference to  FIG. 5 . 
     The substrate S is fixated to the support  110  disposed outside the container  160 , and then the support  110  is moved inside the container  160  through the first transferrer  151 . 
     Herein, when the support  110  moves inside the container  160  through the inlet  161  of the container  160 , the inlet  161  closes, and the support  110  moves to a processing area of the plasma processor  120 . 
     Meanwhile, when the support  110  arrives at a lower side of the plasma processor  120 , the controller  180 , having acknowledged the location of the support  110  through the sensor  170 , controls operations of the plasma processor  120  to output plasma towards the support, more particularly towards the substrate S. 
       FIG. 6  is a schematic view of a substrate plasma processed by a plasma processor in a coating system using a spray nozzle according to  FIG. 1 . 
     With reference to  FIG. 6 , by the plasma being output towards the substrate S, the substrate S is processed to be hydrophilic or hydrophobic, or charged or discharged. And to improve the effectiveness of the processings, the support  110  is provided with voltage or is grounded by the electrode  153 . 
     In an exemplary embodiment of the present disclosure, in order to coat the substrate S with letters ‘ENJET’, the letter part of ‘ENJET’ is processed to be hydrophobic while the background part is processed to be hydrophilic through the plasma processor  120 . 
     Meanwhile, the plasma processed substrate S moves to the lower side of the spray nozzle  130  by the first transferrer  151 , the sensor acknowledges the location of the support  110 , and the controller  180  controls the operations of the spray nozzle  130 . 
       FIG. 7  is a schematic skewed view of coating a plasma processed substrate through a spray nozzle in a coating system using a spray nozzle according to  FIG. 1 . 
     With reference to  FIG. 7 , the spray nozzle  130  injects liquid towards the plasma processed substrate S, the liquid injected towards the substrate S collides with the gas injected from the gas injector  131  between the support  110  and the spray nozzle  130 , and thus a primary atomization of the liquid occurs. By such collision with the gas, the liquid surface becomes unstable, and due to this instability of the liquid surface, a secondary atomization of the liquid by the electric field occurs actively even when the nonpolarity or electrical conductivity of the liquid is extremely low. 
     Herein, in order to prevent the collision with the gas affecting the injection speed of the liquid, the gas collides vertically, without limitation, with the gas. 
     The liquid that has been unstabilized while going through a primary atomization by collision with the gas goes through a secondary atomization by the electric field that occurs between the spray nozzle  130  and the support  110 . Since the liquid has already gone through the primary atomization by collision with the gas, the flow rate of the liquid that can be atomized increases significantly than in the case of atomizing the liquid simply using the electric field only, and this leads the increase of processing speed. 
     Discharging ink in such a method achieves both the advantage of a gas assisted atomizer, that is increase of ink spray amount, and the advantage of electric spraying, that is creation of fine and uniform droplets. Furthermore, guiding the path of the droplets that have gone through a secondary atomization by the electric field between the spray nozzle  130  and the support  110  may resolve all the problems including the rebounding of droplets and increase of ink consumption. Moreover, since it is not a process wherein the liquid surface is changed to taylor-cone on the nozzle and spray is produced at the end, it is possible to perform a secondary atomization on ink made of low electric conductivity material or nonconductive (dielectric) material regardless of the polarity of the ink. Such a principle is based on the mathematical equation below. 
     
       
         
           
             
               
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     Herein,  e  indicates free electron on liquid surface, e dielectric constant, e 0  dielectric constant in vacuum, and E electric field. 
     Herein, in the case of dielectric liquid, in the above equation, the second and third forces will be applied, while in the case of a non-polar liquid, in the above equation, an electric force of the second section will be applied. This is called a dielectrophoretic force. Herein, since there exists only an electric force that acts on the vertical direction of the liquid surface and not in the direction tangent to the liquid surface, there won&#39;t be formed a liquid surface having a conical shape called the taylor-cone, and thus atomizing the liquid will not be easy with only an electric field. 
     However, by making droplets unstable at the same time of performing a primary atomization by inducing collision with gas as in a spray nozzle according to a first exemplary embodiment of the present disclosure  130 , a secondary atomization may occur in spite of a weak dielectrophoretic force. 
     Accordingly, by utilizing a spray nozzle according to an exemplary embodiment of the present disclosure  130 , it is possible to easily induce atomization of even nonconductive liquid regardless of the polarity of the liquid. 
     As aforementioned, the liquid that has gone through the secondary atomization flows towards the substrate S. 
     Herein, depending on the features of the atomized liquid, more particularly depending on whether the atomized liquid is hydrophilic or hydrophobic, coating of the atomized liquid may be concentrated on letters ‘ENJET’, or on the background part of ‘ENJET’. 
     Since the liquid used in an exemplary embodiment of the present disclosure is hydrophobic, the substrate S is coated and a pattern is formed such that the coating of the atomized liquid is concentrated on the letters ‘ENJET’. 
     Meanwhile, when the substrate S which has completed being coated through the spray nozzle  130  is transferred to the outlet  162 , the sensor  170  measures the location the substrate S and opens the outlet  162 , and transfers the substrate S outside the container  160 . 
     A number of examples have been described above. Nevertheless, it will be understood that various modifications may be made. For example, suitable results may be achieved if the described techniques are performed in a different order and/or if components in a described system, architecture, device, or circuit are combined in a different matter and/or replaced or supplemented by other components or their equivalents. Accordingly, other implementations are within the scope of the following claims. 
     DESCRIPTION OF REFERENCE NUMERALS 
     
         
           100 : COATING SYSTEM USING SPRAY NOZZLE 
         S: SUBSTRATE 
           110 : SUPPORT 
           120 : PLASMA PROCESSOR 
           130 : SPRAY NOZZLE 
           140 : VOLTAGE APPLIER 
           150 : TRANSFERRER 
           160 : CONTAINER 
           170 : SENSOR 
           180 : CONTROLLER