Substrate processing apparatus and method of controlling a substrate processing apparatus

Abstract

The present invention provides a substrate processing apparatus. The substrate processing apparatus includes: a head unit configured to discharge ink onto a substrate; a supply unit configured to supply the ink to the head unit and including a reservoir having an internal space; and a pressure adjustment unit configured to adjust the pressure of the internal space, wherein the pressure adjustment unit includes: a first pressure adjustment unit; and a second pressure adjustment unit, wherein the second pressure adjustment unit changes the pressure of the internal space by a greater amount per unit time than the first pressure adjustment unit.

Description

Background Technology

[0001] The embodiments of the inventive concept described herein relate to a substrate processing apparatus and a method for controlling the substrate processing apparatus.

[0002] Recently, there has been a need to manufacture display devices with high resolution, such as liquid crystal displays and organic EL displays. In order to manufacture display devices with high resolution, more pixels per unit area should be formed on a substrate such as glass, and it is important to place ink droplets in precise amounts at precise positions at each of the closely arranged pixels.

[0003] It is necessary to prevent ink from flowing downwards onto the ink-discharging nozzle surface of the printhead, or to prevent ink from forming at the tip of the printhead. This is because if ink flows downwards onto the nozzle surface, or if ink forms at the tip of the nozzle, the ink may solidify due to exposure to outside air. Solidified ink may travel onto substrates such as glass and contaminate them. In some cases, solidified ink may clog the nozzles of the printhead. To address this issue, it is important to maintain the ink in a meniscus state, forming a concave liquid film facing inwards towards the tip of the nozzle, by applying a slight negative pressure to the internal space of the ink reservoir in an atmospheric state when no ink is being discharged.

[0004] On the other hand, if ink is supplied to the head, the internal space of the reservoir is pressurized, and then depressurized to maintain a meniscus shape. That is, the internal space of the reservoir switches between positive and negative pressure. If the pressure of the internal space is switched from positive to negative for a long time, wetting of the ink at the tip of the nozzle may occur due to gravity.

[0005] To reduce the time required to change the pressure in the internal space, one approach could be to increase the orifice size of the servo valve in the pressure controller that controls the pressure in the internal space of the reservoir. However, if the orifice size of the servo valve is increased, it becomes difficult for the pressure controller to accurately control the pressure in the internal space of the reservoir. Summary of the Invention

[0006] Embodiments of the present invention provide a substrate processing apparatus and a substrate processing method for effectively controlling the pressure inside a storage device.

[0007] Embodiments of the present invention provide a substrate processing apparatus and a substrate processing method for reducing the time required to change pressure when changing the pressure inside a storage space between positive and negative pressure.

[0008] Embodiments of the present invention provide a substrate processing apparatus and a substrate processing method for minimizing the wetting phenomenon of ink formed on the nozzle surface of the head.

[0009] The technical objectives of this invention are not limited to those described above, and other unmentioned technical objectives will become apparent to those skilled in the art from the following description.

[0010] The present invention provides a substrate processing apparatus. The substrate processing apparatus includes: a head unit configured to discharge ink onto a substrate; a supply unit configured to supply the ink to the head unit and including a reservoir having an internal space; and a pressure adjustment unit configured to adjust the pressure of the internal space, wherein the pressure adjustment unit includes: a first pressure adjustment unit; and a second pressure adjustment unit, wherein the second pressure adjustment unit changes the pressure of the internal space by a greater amount per unit time than the first pressure adjustment unit.

[0011] In one embodiment, the substrate processing apparatus further includes: a controller for controlling the pressure adjustment unit, wherein after the first pressure adjustment unit changes the pressure of the internal space, the controller controls the pressure adjustment unit such that the second pressure adjustment unit changes the pressure of the internal space, and the pressure of the internal space changes from a first pressure to a second pressure different from the first pressure.

[0012] In one embodiment, after the first pressure adjustment unit changes the pressure of the internal space, the controller controls the pressure adjustment unit to cause the second pressure adjustment unit to change the pressure of the internal space, and the pressure of the internal space changes from atmospheric pressure or positive pressure to negative pressure.

[0013] In one embodiment, the supply unit further includes a pressure measurement sensor for measuring the pressure of the interior space.

[0014] In one embodiment, if the second pressure adjustment unit adjusts the pressure of the internal space and the pressure of the internal space measured by the pressure measuring sensor reaches a predetermined pressure, then the controller controls the pressure adjustment unit so that the first pressure adjustment unit adjusts the pressure of the internal space.

[0015] In one embodiment, the second pressure regulating unit includes: a pressure reducing member that continuously reduces pressure during operation; a pressure reducing line for transmitting the pressure reduction provided by the pressure reducing member to the internal space; and a pressure reducing valve installed at the pressure reducing line.

[0016] In one embodiment, the first pressure adjustment unit includes: a positive pressure providing member configured to provide positive pressure to the interior space; a negative pressure providing member configured to provide negative pressure to the interior space; and a pressure line that transmits pressure provided by the positive pressure providing member or the negative pressure providing member to the interior space.

[0017] In one embodiment, the first pressure adjustment unit further includes a servo valve installed between the positive pressure providing member and / or the negative pressure providing member and the reservoir.

[0018] The present invention provides a method for controlling a substrate processing apparatus. The method includes: pressurizing an internal space of a reservoir storing ink discharged by a head unit, thereby increasing the pressure of the internal space; adjusting the pressure of the internal space to a first pressure after pressurization; and after adjusting the pressure of the internal space to the first pressure, adjusting the pressure of the internal space to a second pressure different from the first pressure, wherein the pressure change per unit time of the internal space when adjusting the pressure to the first pressure is different from the pressure change per unit time of the internal space when adjusting the pressure to the second pressure.

[0019] In one embodiment, the pressure change per unit time of the internal space when the pressure of the internal space is adjusted to the first pressure is less than the pressure change per unit time of the internal space when the pressure of the internal space is adjusted to the second pressure.

[0020] In one embodiment, the pressurization increases the pressure in the interior space from negative pressure to atmospheric pressure, or from negative pressure to positive pressure.

[0021] In one embodiment, the pressurization pressurizes the internal space, causing the pressure in the internal space to become positive, so as to clean the head unit by delivering ink stored in the internal space to the head unit.

[0022] In one embodiment, the pressurization opens the interior space to the atmosphere, causing the pressure in the interior space to become atmospheric pressure to supply the ink from the container into the interior space.

[0023] According to embodiments of the present invention, the pressure inside the storage space can be effectively controlled.

[0024] According to embodiments of the present invention, the time required for pressure change can be reduced when the pressure inside the reservoir is changed between positive and negative pressure.

[0025] According to embodiments of the present invention, wetting of ink formed on the nozzle surface of the head can be minimized.

[0026] The effects of this invention are not limited to those described above, and other effects not mentioned will become apparent to those skilled in the art from the following description. Attached Figure Description

[0027] The above and other objects and features will become apparent from the following description with reference to the accompanying drawings, wherein, unless otherwise stated, the same reference numerals in the various drawings refer to the same parts, and wherein:

[0028] Figure 1 A substrate processing apparatus according to an embodiment of the present invention is shown.

[0029] Figure 2 yes Figure 1 Bottom view of the nozzle surface of the head.

[0030] Figure 3 It is a schematic display Figure 1 A block diagram of the head unit, supply unit, and pressure adjustment unit.

[0031] Figure 4 This is a flowchart illustrating a control method for a substrate processing apparatus according to an embodiment of the present invention.

[0032] Figure 5 The demonstration shows how to adjust the pressure of the interior space. Figure 4 The status of the head unit, supply unit, and pressure adjustment unit under the first pressure.

[0033] Figure 6 The demonstration shows how to adjust the pressure of the interior space. Figure 4 The status of the head unit, supply unit, and pressure adjustment unit during the first time period of the second pressure.

[0034] Figure 7 The demonstration shows how to adjust the pressure of the interior space. Figure 4 The status of the head unit, supply unit, and pressure adjustment unit during the second time period of the second pressure.

[0035] Figure 8 and Figure 9The demonstration shows how the ink at the tip of the nozzle transforms into a meniscus state when the pressure in the internal space is adjusted to the second pressure.

[0036] Figure 10 The demonstration shows how to adjust the pressure of the interior space. Figure 4 Another example of the head unit, supply unit, and pressure adjustment unit under first pressure. Detailed Implementation

[0037] The inventive concept can be modified and taken in various forms, and specific embodiments of the inventive concept will be shown and described in detail in the accompanying drawings. However, the embodiments of the inventive concept are not intended to limit the specific forms disclosed, and it should be understood that the inventive concept includes all variations, equivalents, and substitutions included within the spirit and scope of the inventive concept. In the description of the inventive concept, detailed descriptions of relevant prior art may be omitted where it may obscure the essence of the inventive concept.

[0038] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the inventive concept. As used herein, the word “the” is intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that, when used in this specification, the terms “comprise” and / or “comprising” specify the presence of the stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof. As used herein, the terms “and / or” include any and all combinations of one or more of the associated listed items. Furthermore, the term “exemplary” is intended to refer to an example or illustration.

[0039] It should be understood that although the terms "first," "second," "third," etc., may be used herein to describe various elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another region, layer, or section. Therefore, without departing from the teachings of the inventive concept, the first element, first component, first region, first layer, or first section discussed below may be referred to as a second element, second component, second region, second layer, or second section.

[0040] It should be understood that when a component or layer is referred to as "connected to" or "attached to" another component or layer, it may be directly connected to, attached to, or cover the other component or layer, or there may be intermediate components or layers. Conversely, when a component is referred to as "directly connected to" or "directly attached to" another component, there are no intermediate components or layers. Other terms such as "between," "adjacent," or "nearby" should be interpreted in the same manner.

[0041] Unless otherwise defined, all terms used herein (including technical or scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which the inventive concept pertains. Terms such as those defined in common dictionaries shall be interpreted in accordance with the context of the relevant art and shall not be interpreted as ideal or overly formal, unless clearly defined in this application.

[0042] In the following text, reference will be made to Figures 1 to 10 Embodiments of the present invention are described.

[0043] Figure 1 A substrate processing apparatus according to an embodiment of the present invention is shown.

[0044] refer to Figure 1 According to an embodiment of the present invention, the substrate processing apparatus 100 can be an inkjet printer that processes a substrate by supplying a processing liquid, such as ink, onto a substrate S. The substrate S may include: a first substrate S1, which is the substrate to be processed; and a second substrate S2, which is a dummy substrate used to correct the landing position, emission time, etc., of ink I in the form of droplets emitted onto the first substrate S1. Alternatively, the substrate S may be glass. The substrate processing apparatus 100 can perform a printing process on the substrate S by emitting ink droplets onto the substrate S.

[0045] The substrate processing equipment 100 may include a printing unit 10, a maintenance unit 20, a frame 30, a head unit 40, a nozzle alignment unit 50, a supply unit 60, a pressure adjustment unit 70, a tank 80, and a controller 90.

[0046] When viewed from above, the printing unit 10 can be configured such that its longitudinal direction is in the first direction X. Hereinafter, when viewed from above, the direction perpendicular to the first direction X is referred to as the second direction Y, and the direction perpendicular to both the first and second directions Y is referred to as the third direction Z. The third direction Z can be a direction perpendicular to the ground. Alternatively, the first direction X can be the direction in which the first substrate S1, described later, is conveyed by the conveying member 12. In the printing unit 10, the printing process on the first substrate S1 can be performed by discharging ink from the head unit 40, described later, onto the first substrate S1.

[0047] Furthermore, the first substrate S1 transported from the printing unit 10 can be maintained in a floating state. Therefore, the printing unit 10 can be provided with a floating stage capable of floating the first substrate S1 during transport. The floating stage can supply air to the bottom surface of the first substrate S1 to allow the first substrate S1 to float.

[0048] The transfer member 12 can grip one or both sides of the first substrate S1 in the printing unit 10 to move the first substrate S1 along the first direction X. The transfer member 12 can grip the bottom surface of the edge region of the first substrate S1 using a vacuum suction method. The transfer member 12 can move along a guide rail provided in the longitudinal direction of the printing unit 10. That is, the transfer unit 70 may include a guide rail provided along one or both sides of the floating stage, and a gripper that slides along the guide rail when gripping one or both sides of the first substrate S1.

[0049] In addition, the maintenance unit 20 is also provided with a transfer member having the same structure and / or similar function as the transfer member 12 provided to the printing unit 10, and therefore the maintenance unit 20 can move the second substrate S2 in the first direction X.

[0050] Maintenance of the head unit 40, which will be described later, is primarily performed at the maintenance unit 20. For example, the maintenance unit 20 may check the condition of the head unit 40 or perform cleaning of the head unit 40. When viewed from above, the maintenance unit 20 may be positioned such that its longitudinal direction is in the first direction X. Furthermore, the maintenance unit 20 may be arranged side-by-side with the printing unit 10. For example, the maintenance unit 20 and the printing unit 10 may be arranged parallel to each other in the second direction Y.

[0051] Furthermore, in the case of maintenance unit 20, since ink in the form of droplets can be discharged to perform the correction of the landing position of the droplet ink discharged by the head unit 40 (described later), the volume adjustment of ink I, and the control of the discharge volume of ink I, maintenance unit 20 can have the same or similar process environment as printing unit 10.

[0052] The frame 30 can be configured such that the head unit 40, described later, or the fourth vision unit 60, described later, can reciprocate in a straight line. The frame 30 may include a first frame 31, a second frame 32, and a third frame 33. The first frame 31 and the second frame 32 can be configured to extend along the printing unit 10 and the maintenance unit 20. Furthermore, the first frame 31 and the second frame 32 can be spaced apart from each other in a first direction X. That is, the first frame 31 and the second frame 32 can be configured to extend in a second direction Y, wherein the printing unit 10 and the maintenance unit 20 are configured such that the head unit 40, described later, can move in the second direction Y.

[0053] Additionally, the third frame 33 can be configured with the printing unit 10 extending along the second direction Y. That is, the third frame 33 can be configured with a fourth vision unit 33a extending to move along the second direction Y. The fourth vision unit 33a can reciprocate along the third frame 33 to obtain images capable of confirming the landing position and volume of the droplets of ink discharged from the maintenance unit 20. For example, the head unit 40 can discharge ink droplets onto a calibration plate (e.g., the second substrate S2), which can be positioned on the maintenance unit 20. The second substrate S2 can move to the bottom region of the fourth vision unit 33a, and the fourth vision unit 33a can acquire an image of the second substrate S2 from which ink droplets are discharged. The image acquired by the fourth vision unit 33a can be transmitted to the controller 90. The fourth vision unit 33a can be a camera including an image acquisition module.

[0054] Figure 2 exhibit Figure 1 The nozzle plate at the head.

[0055] refer to Figures 1 to 2 The head unit 40 can discharge ink in droplet form onto the substrate S. The head unit 40 can perform a printing process on the substrate S by discharging ink I onto the substrate S. For example, the head unit 40 can perform a printing process on the substrate S by discharging ink I onto the substrate S while reciprocating along the second direction Y. For example, the head unit 40 can discharge ink I onto a first substrate S1 that is moving in the first direction X. If the first substrate S1 enters a region below the head unit 40 and then deviates from the region below the head unit 40, the head unit 40 can move along the second direction Y to change the discharge position of ink I. If the discharge position of ink I of the head unit 40 is changed, the first substrate S1 can move along the first direction X, but it can also move in the opposite direction to the previous movement. When the first substrate S1 moves in the opposite direction, the head unit 40 can discharge ink I.

[0056] The head unit 40 may include an ink storage member 41, a head 42, an emission member 43, a head frame 44, a head interface plate 45, a first vision unit 46, and a second vision unit 48. The head unit 40 can emit ink in the form of droplets onto the substrate S that is moving at a certain speed by the aforementioned conveying unit 70.

[0057] Multiple heads 42 can be provided. The multiple heads 42 can be arranged side by side along the first direction X. The multiple heads 42 can be assembled to the head frame 44. In addition, at least one nozzle 42b can be formed at the head 42. The nozzle surface 41a on which the nozzle 42b is formed can be parallel to the top surface of the substrate S.

[0058] In addition, the head unit 40 may include a discharge member (not shown) for discharging ink I. The discharge member may be a piezoelectric element. The discharge member 43 may receive a droplet discharge signal from the controller 90 to realize the liquid discharge operation of the head unit 40.

[0059] The first visual unit 46 and the second visual unit 48 can be mounted at the head frame 44. Additionally, when viewed from above, the first visual unit 46 and the second visual unit 48 can be connected to one side of the head 42. The first visual unit 46 and the second visual unit 48 can acquire images capable of identifying the landing position and volume of ink droplets discharged from the head unit 40 onto the substrate S. For example, when the head unit 40 discharges ink droplets onto the substrate S disposed at the printing unit 10, the first visual unit 46 and the second visual unit 48 can take a picture of the substrate S, and the captured image can be transmitted to the controller 90. The user can check the landing position or volume of the ink droplets discharged onto the substrate S by the images captured by the first visual unit 46 and the second visual unit 48 and transmitted to the controller 90. The first visual unit 46 and the second visual unit 48 can be arranged side-by-side in the first direction X. The first visual unit 46 and the second visual unit 48 can be cameras capable of identifying ink droplets discharged from the head 42.

[0060] The head 42 can be movably connected to the first frame 31 and the second frame 32 via the head frame 44. For example, the head 42 can be configured to move along a second direction Y, which is the longitudinal direction of the first frame 31 and the second frame 32. In addition, the head 42 can reciprocate between the printing unit 10 and the maintenance unit 20 along the second direction Y, which is the longitudinal direction of the first frame 31 and the second frame 32.

[0061] Return to reference Figure 1 The nozzle alignment unit 50 can be disposed within the maintenance unit 20. When viewed from above, the nozzle alignment unit 50 can be positioned between the first frame 31 and the second frame 32. Therefore, the nozzle alignment unit 50 can inspect the state of the nozzles 42b formed at the head 42. For example, the nozzle alignment unit 50 may include a moving track 52 and a third vision unit 54. The longitudinal direction of the moving track 52 may be a first direction X. The third vision unit 54 can reciprocate along the first direction X, which is the longitudinal direction of the moving track 52. The third vision unit 54 can take pictures of the nozzles 42b of the head 42 while moving along the longitudinal direction of the moving track 52.

[0062] Figure 3 It is a schematic display Figure 1 A block diagram of the head unit, supply unit, and pressure adjustment unit.

[0063] refer to Figure 3The supply unit 60 can supply ink I to the head unit 40. The supply unit 60 may include a reservoir 61, a pressure measuring sensor 63, a supply line 64, and a supply valve 65.

[0064] The reservoir 61 may have an internal space 62. The reservoir 61 can store ink I delivered to the head unit 40. The reservoir 61 may be disposed between the head unit 40 and the tank 80, which will be described later. A pressure measuring sensor 63 may be disposed within the internal space 62 of the reservoir 61. The pressure measuring sensor 63 can measure the pressure of the internal space 62. The pressure measuring sensor 63 can measure the pressure of the internal space 62 and transmit the measured pressure value of the internal space 62 to the controller 90, which will be described later. Additionally, a flow member (not shown) for maintaining the fluidity of the ink I may be installed within the internal space 62. If the ink I does not flow within the internal space 62, it may solidify within the internal space 62, and the flow member can minimize the occurrence of ink I solidification by ensuring that the ink I flows within the internal space 62.

[0065] The supply line 64 can deliver ink I stored / retained in the internal space 62 of the reservoir 61 to the head unit 40. The supply line 64 can deliver ink I stored / retained in the internal space 62 to the head unit 40, and the head unit 40, having received ink I, can discharge ink I onto the substrate S. A supply valve 65 can be installed at the supply line 64. The supply valve 65 can be an on / off valve or a flow control valve capable of adjusting the amount of ink delivered to the head unit 40 per unit time via the supply line 64.

[0066] The pressure adjustment unit 70 can adjust the pressure of the internal space 62. The pressure adjustment unit 70 can increase the pressure of the internal space 62 by supplying an inert gas (such as nitrogen) to the internal space 62. Alternatively, the pressure adjustment unit 70 can reduce the pressure of the internal space 62 by vacuum suction. Furthermore, the pressure adjustment unit 70 can open the internal space 62 to atmospheric pressure, allowing the pressure of the internal space 62 to reach atmospheric pressure. The pressure adjustment unit 70 can switch the pressure of the internal space 62 between positive and negative pressure. For example, the pressure adjustment unit 70 can pressurize the internal space 62 during cleaning to care for the head unit 40. For example, when cleaning the head unit 40, the pressure adjustment unit 70 can pressurize the internal space 62 to a pressure of 200 kPa. Alternatively, the pressure adjustment unit 70 can depressurize the internal space 62 to maintain a meniscus shape at the end portion of the nozzle 42b. For example, the pressure adjustment unit 70 can depressurize the internal space 62 to a pressure of -5 kPa.

[0067] The pressure adjustment unit 70 may include a first pressure adjustment unit 71 and a second pressure adjustment unit 76. The first pressure adjustment unit 71 can adjust the pressure of the internal space 62. The first pressure adjustment unit 71 can provide positive or negative pressure to the internal space 62. The second pressure adjustment unit 76 can adjust the pressure of the internal space 62. The second pressure adjustment unit 71 can provide negative pressure, either positive or negative, to the internal space 62. The first pressure adjustment unit 71 can adjust the pressure of the internal space 62 more precisely than the second pressure adjustment unit 76. For example, the second pressure adjustment unit 76 can change the pressure of the internal space 62 by a greater amount per unit time than the first pressure adjustment unit 71. The first pressure adjustment unit 71 may be an element for maintaining the meniscus state of the end portion of the nozzle 41b, which will be described later. For example, the first pressure adjustment unit 71 may be referred to as a meniscus pressure controller (MPC). The second pressure adjustment unit 76 may be referred to as an electronic regulator. Additionally, the first pressure adjustment unit 71 can open the internal space 62 to the atmosphere, allowing the pressure in the internal space 62 to reach atmospheric pressure.

[0068] The first pressure adjustment unit 71 may include a positive pressure supply component 72, a negative pressure supply component 73, a pressure line 74, and a servo valve 75.

[0069] Positive pressure supply member 72 can provide positive pressure to the internal space 62. Positive pressure supply member 72 can pressurize the internal space 62 by supplying an inert gas (e.g., nitrogen) to the internal space 62. Negative pressure supply member 73 can provide negative pressure to the internal space 62. Negative pressure supply member 73 can provide negative pressure to the internal space 62 by vacuum suction. Pressure line 74 can transmit the pressure (positive or negative) provided by positive pressure supply member 72 or negative pressure supply member 73 to the internal space 62. Servo valve 75 can be installed at pressure line 74. The orifice size of servo valve 75 can be from approximately Φ0.4 mm to Φ1.5 mm. For example, the orifice size of servo valve 75 can be approximately Φ0.4 mm. As the orifice size of servo valve 75 decreases, the pressure provided by the first pressure adjustment unit 71 can be precisely controlled. The accuracy of the pressure provided by the first pressure adjustment unit 71 can be approximately ±15 Pa.

[0070] The second pressure regulating unit 76 can reduce the pressure in the internal space 62. The second pressure regulating unit 76 may include a pressure reducing member 77, a pressure reducing line 78, and a pressure reducing valve 79. The pressure reducing member 77 can reduce the pressure in the internal space 62 by vacuum suction. The pressure reducing member 77 may include a vacuum pump. The pressure reducing member 77 can continuously provide pressure reduction during operation. The pressure provided by the pressure reducing member 77 can be transmitted to the internal space 62 through the pressure reducing line 78. The pressure reducing valve 79 can be installed in the pressure reducing line 78. The pressure reducing valve 79 can be an on / off valve. Since the pressure reducing member 77 always provides pressure reduction during operation, whether the pressure reduction generated by the pressure reducing member 77 is transmitted to the internal space 62 varies depending on whether the pressure reducing valve 79 is open or closed. For example, if the pressure reducing valve 79 is open, the pressure reduction generated by the pressure reducing member 77 can be transmitted to the internal space 62. On the other hand, if the pressure reducing valve 79 is closed, the pressure reduction generated by the pressure reducing valve 79 may not be transmitted to the internal space 62 and may be blocked.

[0071] Furthermore, as described above, the second pressure adjustment unit 76 can change the pressure of the internal space 62 by a greater amount per unit time than the first pressure adjustment unit 71. Additionally, the first pressure adjustment unit 71 can achieve higher control precision for the pressure control of the internal space 62 compared to the second pressure adjustment unit 76.

[0072] The canister 80 can be configured to supply ink I to the internal space 62. The canister 80, used to supply ink I to the reservoir 61, can be configured to have a structure similar to a storage tank for storing ink I. Since the canister 80 has the same structure as a storage tank, it can be positioned at a location slightly spaced from the reservoir 61. Furthermore, since the canister 80 is positioned slightly spaced from the reservoir 61, it can be configured to supply ink I to the reservoir 61 using pressure.

[0073] The tank 80 can supply ink to the internal space 62 via the transfer line 82. The tank 80 can directly supply ink I to the internal space 62. Optionally, a buffer reservoir (not shown) is disposed between the tank 80 and the reservoir 61, and the tank 80 can indirectly supply ink I to the internal space 62. The tank 80 can supply ink I to the buffer reservoir, and the buffer reservoir can supply ink to the reservoir 61.

[0074] The controller 90 can control the substrate processing apparatus 100. The controller 90 can control the substrate processing apparatus 100 so that the substrate processing apparatus 100 can perform a printing process on the substrate S. In addition, the controller 90 can control the head unit 40 so that the head unit 40 of the substrate processing apparatus 100 can discharge ink droplets onto the substrate S to perform a printing process on the substrate S (e.g., the first substrate S1).

[0075] The controller 90 may also be configured as a computer program stored in a computer-readable medium, the computer-readable medium including at least one processor that performs control of the substrate processing apparatus 100, including instructions for such processor to execute for controlling the operation of the substrate processing apparatus 100. Additionally, the controller 90 may include a user interface formed by a keyboard, wherein an operator performs command input operations to manage the substrate processing apparatus 100, a display for visualizing and displaying the operating status of the substrate processing apparatus 100, etc. Furthermore, the user interface and a storage unit may be connected to the processor.

[0076] Figure 4 This is a flowchart illustrating a control method for a substrate processing apparatus according to an embodiment of the present invention. In order to execute the control method for the substrate processing apparatus 100 described below, the controller 90 can control the components of the substrate processing apparatus 100.

[0077] refer to Figure 4 The control method of the substrate processing apparatus according to an embodiment of the present invention may include a pressurization step S00, a first pressure adjustment step S10, and a second pressure adjustment step S20. The pressurization step S00, the first pressure adjustment step S10, and the second pressure adjustment step may be executed sequentially.

[0078] The pressurization step S00 can be a step of increasing the pressure of the internal space 62. In the pressurization step S00, the pressure of the internal space 62 can be increased from negative pressure to atmospheric pressure. For example, if ink I is supplied from the container 80 to the internal space 62, it is necessary to change the internal space 62 from negative pressure (e.g., about -5 kPa, to maintain the meniscus state described later) to atmospheric pressure. The first pressure adjustment unit 71 can increase the pressure of the internal space 62 from negative pressure to atmospheric pressure by opening the internal space 62 to atmospheric pressure (see [link to relevant documentation]). Figure 5 ).

[0079] In the first pressure adjustment step S10, the pressure of the internal space 62 can be adjusted to a first pressure. The first pressure adjustment step S10 can be executed by the second pressure adjustment unit 76 described above. In the first pressure adjustment step S10, the pressure of the internal space 62 can be adjusted from an initial pressure (e.g., atmospheric pressure) to a first pressure that is lower than the initial pressure. The first pressure can be positive or negative. The pressure change per unit time of the internal space 62 in the first pressure adjustment step S10 can be greater than the pressure change per unit time of the internal space 62 in the second pressure adjustment step S20, which will be described later. That is, in the first pressure adjustment step S10, the first pressure, which is lower than the initial pressure, can be reached quickly (see...). Figure 6 ).

[0080] The second pressure adjustment step S20 can be executed after the first pressure adjustment step S10. The transition from the first pressure adjustment step (S10) to the second pressure adjustment step S20 can be based on the pressure value measured by the pressure sensor 63. For example, if the pressure value measured by the pressure sensor 63 reaches a predetermined pressure (e.g., -3 kPa), the open and closed states of the pressure reducing valve 79 and the servo valve 75 can be switched. The controller 90 can generate a control signal for switching the open and closed states of the pressure reducing valve 79 and the servo valve 75 based on the pressure value measured by the pressure sensor 63.

[0081] In the second pressure adjustment step S20, the pressure in the internal space 62 can be adjusted from the first pressure to the second pressure. The second pressure can be different from both the first pressure and the initial pressure. The second pressure can be lower than the first pressure. The second pressure can be negative. For example, the second pressure can be approximately -5 kPa. The second pressure adjustment step S20 can be performed by the first pressure adjustment unit 71. The pressure change per unit time in the internal space 62 during the second pressure adjustment step S20 can be less than the pressure change per unit time in the internal space 62 during the first pressure adjustment step S10. Furthermore, as described above, the second pressure adjustment step S20 is performed by the first pressure adjustment unit 71, which has relatively high pressure control accuracy (see [link]). Figure 7 Therefore, in the second pressure adjustment step S20, the pressure in the internal space 62 can be precisely controlled.

[0082] If the pressure in the internal space 62 reaches a negative pressure, the ink I at the end portion of the nozzle 42b is drawn upward, thereby maintaining the ink I in a meniscus state, forming a concave liquid film facing inward toward the nozzle 42b (see...). Figure 8 and Figure 9 ).

[0083] Furthermore, if it takes a long time for the pressure in the internal space 62 to change from positive to negative, the ink I will be pulled downwards under the influence of gravity, thereby solidifying at the end portion of the nozzle 42b or flowing downwards along the nozzle 42a. However, the present invention can minimize the occurrence of the above problems by using two systems to control the pressure in the internal space 62: a second pressure adjustment unit 76 that can quickly change the pressure and a first pressure adjustment unit 71 that can precisely control the pressure.

[0084] Additionally, in the above example, the pressurization step S00 has been described as an example of changing the pressure in the internal space 62 from negative pressure to atmospheric pressure, but it is not limited to this. For example, the head unit 40 may need to be cleaned if necessary. In order for the head unit 40 to expel unused ink I remaining in the nozzle 42b of the head unit 40, it may be necessary to clean the head unit 40. Cleaning can be performed by transferring ink stored in the internal space 62 to the head unit 40. For example, cleaning can be performed by providing positive pressure to the internal space 62 through the first pressure adjustment unit 71, or by the tank 80 pressurizing the internal space 62 by supplying ink to the internal space 62.

[0085] The head unit 40 can be cleaned by supplying an inert gas (such as nitrogen) to the internal space 62 and pressurizing the internal space 62 to a high pressure of approximately 200 kPa (see [link]). Figure 10 After the internal space 62 is pressurized to a high pressure of approximately 200 kPa, it may take a long time to switch back to a negative pressure of approximately -5 kPa. However, the present invention can effectively shorten the time required for large pressure changes by providing a second pressure adjustment unit 76 with a large pressure change per unit time.

[0086] In the above example, the substrate S is conveyed by the transfer unit 70 and the position of the head unit 40 is fixed relative to the substrate S during the printing process, but the inventive concept is not limited thereto. For example, the position of the substrate S may be fixed during the printing process, and the position of the head unit 40 may be changed. That is, the movement of the substrate S should be understood as a change in the relative position between the substrate S and the head unit 40.

[0087] The effects of this invention are not limited to those described above, and those skilled in the art to which this invention pertains can clearly understand any effects not mentioned from the specification and drawings.

[0088] Although preferred embodiments of the inventive concept have been shown and described up to now, the inventive concept is not limited to the specific embodiments described above, and it should be noted that those skilled in the art to which the inventive concept relates can implement the inventive concept differently without departing from the essence of the inventive concept as claimed in the claims, and should not be interpreted or modified separately from the technical spirit or prospect of the inventive concept.

Claims

1. A substrate processing apparatus, comprising: A head unit configured to discharge ink onto a substrate; A supply unit configured to supply ink to the head unit and including a reservoir with an internal space; as well as A pressure adjustment unit, configured to adjust the pressure of the internal space, and The pressure adjustment unit includes: A first pressure adjustment unit, the first pressure adjustment unit comprising: A positive pressure providing member, configured to provide positive pressure to the interior space; and A negative pressure providing member configured to provide negative pressure to the interior space; and A second pressure adjustment unit, wherein the pressure change of the internal space per unit time is greater than that of the first pressure adjustment unit, wherein the second pressure adjustment unit includes a pressure reduction component that continuously reduces pressure during operation.

2. The substrate processing apparatus according to claim 1 further includes a controller, the controller being used to control the pressure adjustment unit, and After the first pressure adjustment unit changes the pressure of the internal space, the controller controls the pressure adjustment unit to cause the second pressure adjustment unit to change the pressure of the internal space, and the pressure of the internal space changes from a first pressure to a second pressure different from the first pressure.

3. The substrate processing apparatus according to claim 2, wherein after the first pressure adjustment unit changes the pressure of the internal space, the controller controls the pressure adjustment unit to cause the second pressure adjustment unit to change the pressure of the internal space, and the pressure of the internal space changes from atmospheric pressure or positive pressure to negative pressure.

4. The substrate processing apparatus according to claim 2 or claim 3, wherein the supply unit further comprises a pressure measuring sensor for measuring the pressure of the internal space.

5. The substrate processing apparatus according to claim 4, wherein if the second pressure adjustment unit adjusts the pressure of the internal space and the pressure of the internal space measured by the pressure measuring sensor reaches a predetermined pressure, the controller controls the pressure adjustment unit such that the first pressure adjustment unit adjusts the pressure of the internal space.

6. The substrate processing apparatus according to any one of claims 1 to 3, wherein the second pressure adjustment unit further comprises: A pressure-reducing line for transmitting the pressure reduction provided by the pressure-reducing component to the internal space; as well as A pressure reducing valve is installed at the pressure reducing line.

7. The substrate processing apparatus according to any one of claims 1 to 3, wherein the first pressure adjustment unit further comprises: A pressure line that transmits pressure provided by the positive pressure supplying member or the negative pressure supplying member to the internal space.

8. The substrate processing apparatus of claim 7, wherein the first pressure adjustment unit further comprises a servo valve installed between the positive pressure providing member and / or the negative pressure providing member and the reservoir.

9. A method for controlling a substrate processing apparatus as described in any one of claims 1 to 8, comprising: The first pressure adjustment unit pressurizes the internal space of the reservoir storing ink discharged from the head unit, thereby increasing the pressure in the internal space. After pressurization, the pressure in the internal space is adjusted to a first pressure via a second pressure adjustment unit; and After adjusting the pressure of the internal space to the first pressure, the pressure of the internal space is adjusted to a second pressure different from the first pressure by the first pressure adjustment unit, and Wherein, when the pressure of the internal space is adjusted to the first pressure, the pressure change per unit time of the internal space is greater than when the pressure of the internal space is adjusted to the second pressure.

10. The method of claim 9, wherein the pressurization increases the pressure in the interior space from negative pressure to atmospheric pressure, or from negative pressure to positive pressure.

11. The method of claim 10, wherein the pressurization pressurizes the internal space such that the pressure in the internal space becomes the positive pressure, so as to clean the head unit by transferring ink stored in the internal space to the head unit.

12. The method of claim 10, wherein the pressurization opens the interior space to the atmosphere, such that the pressure in the interior space becomes atmospheric pressure to supply the ink from the container into the interior space.

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