Inkjet printing device and manufacturing method of display panel

Abstract

An inkjet printing device may include a head unit, a waste ink collection module, a first storage unit in which a first material containing a plurality of particles is stored, a first particle separation unit that discharges a first separation material containing a first particle of a predetermined size or larger among the plurality of particles to the waste ink collection module and discharges a second separation material containing a second particle of a predetermined size or smaller among the plurality of particles to the head unit, and a second particle separation unit that discharges a third separation material containing a third particle of a predetermined size or larger among the plurality of particles to the waste ink collection module and discharges a fourth separation material containing a fourth particle of a predetermined size or smaller among the plurality of particles to the first storage unit.

Description

Technology Field

[0001] The present invention relates to an inkjet printing device with improved productivity and a method for manufacturing a display panel using the same. Background Technology

[0002] An optical pattern, color filter, or light-emitting layer of a display panel can be formed using an inkjet printing device. For example, an inkjet printing device can form components constituting a display panel by discharging ink containing a base material and particles dispersed in the base material onto a target substrate. The problem to be solved

[0003] One objective of the present invention is to provide an inkjet printing device with improved productivity.

[0004] One objective of the present invention is to provide a method for manufacturing a display panel using an inkjet printing device with improved productivity. means of solving the problem

[0005] An inkjet printing device according to one embodiment of the present invention may include a head unit including a nozzle for discharging ink, a waste ink collection module, a first storage unit in which a first material including a plurality of particles is stored, a first particle separation unit into which the first material discharged from the first storage unit is introduced, a first separation material including a first particle of a first predetermined size or larger among the plurality of particles is discharged to the waste ink collection module, and a second separation material including a second particle of a second size or smaller among the plurality of particles is discharged to the head unit, and a second particle separation unit into which the first material discharged from the first storage unit is introduced, a third separation material including a third particle of a second predetermined size or larger among the plurality of particles is discharged to the waste ink collection module, and a fourth separation material including a fourth particle of a second predetermined size or smaller among the plurality of particles is discharged to the first storage unit.

[0006] The inkjet printing device further includes a second storage unit in which a second material is stored, and the first material and the second material may be introduced into each of the first particle separation unit and the second particle separation unit.

[0007] The first material further comprises a base material in which the plurality of particles are dispersed, and the second material may comprise the base material.

[0008] The first particle separation unit includes a first internal passage and a first surface elastic wave generating unit adjacent to the first internal passage, and the second particle separation unit may include a second internal passage and a second surface elastic wave generating unit adjacent to the second internal passage.

[0009] The first internal passage may include a first conduit connected to the first storage unit, a second conduit connected to the second storage unit, a third conduit connected to the head unit, and a fourth conduit connected to the waste ink collection module. The second internal passage may include a fifth conduit connected to the first storage unit through which the first substance flows, a sixth conduit connected to the second storage unit, a seventh conduit connected to the first storage unit through which the fourth separated substance is discharged, and an eighth conduit connected to the waste ink collection module.

[0010] The inkjet printing device may further include a control unit that controls the wavelength and intensity of each of the first surface acoustic wave and the second surface acoustic wave.

[0011] The inkjet printing device may further include a first supply unit that supplies the first material to the first storage unit and a second supply unit that supplies the second material to the second storage unit.

[0012] The inkjet printing device may further include a first pump disposed between the first storage unit and the second particle separation unit to move the first material, and may further include a second pump disposed between the second storage unit and the second particle separation unit to move the second material.

[0013] The inkjet printing device may include a plurality of the first particle separation units and a plurality of the second particle separation units.

[0014] The inkjet printing device may further include a valve disposed between the first storage unit and the first particle separation unit to control the movement of the first material.

[0015] The inkjet printing device may further include a pump disposed between the head unit and the first storage unit to move the second separated material, and the head unit may discharge a portion of the second separated material to the first storage unit.

[0016] The inkjet printing device may further include a valve disposed between the head unit and the first storage unit to control the movement of the second separated material.

[0017] The inkjet printing device may further include a concentration measuring unit that measures the concentration of the second separated substance moving from the head unit to the first storage unit, and a base substance supply unit that provides a base substance to the first storage unit based on the concentration.

[0018] The inkjet printing device may further include a grinding unit that grinds the first particles contained in the first separation material and the third particles contained in the third separation material stored in the waste ink collection module.

[0019] An inkjet printing device according to one embodiment of the present invention may include a first storage unit in which a first material comprising a plurality of particles and a base material in which the plurality of particles are dispersed is stored; a second storage unit in which the base material is stored; a first particle separation unit into which the first material discharged from the first storage unit and the base material discharged from the second storage unit are introduced, and which separates a first particle of a predetermined size or larger among the plurality of particles; a second particle separation unit into which the first material discharged from the first storage unit and the base material discharged from the second storage unit are introduced, and which separates a third particle of a predetermined size or larger among the plurality of particles; a waste ink collection module that receives the first particle and the third particle; and a head unit into which ink from which the first particle and the third particle have been removed from the first material and the base material is introduced.

[0020] Each of the first particle separation unit and the second particle separation unit may be a surface elastic wave module.

[0021] According to one embodiment of the present invention, the method may include the steps of: providing a base material and a plurality of particles stored in a storage unit to a first particle separation unit; providing the base material and the plurality of particles stored in the storage unit to a second particle separation unit; separating the plurality of particles introduced into the first particle separation unit into a first particle having a size greater than or equal to a first predetermined size and a second particle having a size less than or equal to the first predetermined size using surface elastic waves; separating the plurality of particles introduced into the second particle separation unit into a third particle having a size greater than or equal to a second predetermined size and a fourth particle having a size less than or equal to the second predetermined size using surface elastic waves; and discharging the ink from which the first particle and the third particle have been removed onto a substrate using a head unit.

[0022] The step of separating the first particle and the second particle may include providing the first particle to a waste ink collection module and providing the second particle to the head unit. The step of separating the third particle and the fourth particle may include providing the third particle to the waste ink collection module and providing the fourth particle to the storage unit.

[0023] The above storage unit may include a first storage section in which a portion of the base material and the plurality of particles are stored, and a second storage section in which a portion of the base material is stored. Each of the first particle separation section and the second particle separation section may receive the base material and the plurality of particles from the first storage section and the second storage section.

[0024] In the method for manufacturing the display device above, each of the step of separating the first particle and the second particle, and the step of separating the third particle and the fourth particle, may include the step of adjusting the wavelength and intensity of the surface elastic wave according to the first predetermined size or the second predetermined size. Effects of the invention

[0025] As described above, the inkjet printing device may include a first particle separation unit and a second particle separation unit. By a circulation process using the second particle separation unit, the concentration of particles larger than a predetermined size that move to the head unit can be reduced. As a result, the amount of particles that need to be separated in the first particle separation unit is reduced, and the purity of particles smaller than a predetermined size of the ink moving to the head unit can be increased.

[0026] In addition, the first particle separation unit and the second particle separation unit may each be a surface acoustic wave module. Using a surface acoustic wave module eliminates the need for filters that must be periodically discarded, thereby preventing environmental pollution. Furthermore, the elimination of filter replacement work reduces costs associated with replacement and increases production time, which can improve productivity. Brief explanation of the drawing

[0027] FIG. 1 is a cross-sectional view of an inkjet printing device according to one embodiment of the invention. FIG. 2a is a cross-sectional view of a first particle separation section according to one embodiment of the present invention. FIG. 2b is a cross-sectional view of a second particle separation unit according to one embodiment of the present invention. FIG. 3a is a diagram illustrating the connection relationship between a first storage unit and a first particle separation unit according to an embodiment of the present invention. FIG. 3b is a diagram illustrating the connection relationship between a second storage unit and a first particle separation unit according to an embodiment of the present invention. FIG. 3c is a diagram illustrating the connection relationship between the first particle separation unit and the head unit according to one embodiment of the present invention. FIG. 3d is a diagram illustrating the connection relationship between a first particle separation unit and a waste ink collection module according to one embodiment of the present invention. FIG. 3e is a diagram illustrating the connection relationship between the second particle separation unit and the first storage unit according to one embodiment of the present invention. FIG. 4 is a cross-sectional view of an inkjet printing device according to an embodiment of the invention. FIG. 5 is a cross-sectional view of an inkjet printing device according to one embodiment of the invention. FIG. 6 is a cross-sectional view of an inkjet printing device according to one embodiment of the invention. FIG. 7 is a cross-sectional view of an inkjet printing device according to one embodiment of the invention. FIG. 8a is a flowchart of a method for manufacturing a display device according to one embodiment of the present invention. FIG. 8b is a flowchart illustrating the operation of a first particle separation unit according to an embodiment of the present invention. FIG. 8c is a flowchart illustrating the operation of a second particle separation unit according to an embodiment of the present invention. FIG. 9 is a cross-sectional view illustrating a display device formed according to one embodiment of the present invention. Figure 10 is a drawing illustrating some of the processes of the manufacturing method of the display panel shown in Figure 9. Specific details for implementing the invention

[0028] In this specification, where a component (or region, layer, part, etc.) is described as being “on,” “connected,” or “joined” another component, it means that it may be directly placed / connected / joined on the other component, or that a third component may be placed between them.

[0029] Identical reference numerals denote identical components. Additionally, in the drawings, the thicknesses, proportions, and dimensions of components are exaggerated for the effective illustration of the technical content. “And / or” includes all one or more combinations that the associated components may define.

[0030] Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component. A singular expression includes a plural expression unless the context clearly indicates otherwise.

[0031] Additionally, terms such as “below,” “lower,” “above,” and “upper” are used to describe the relationships between the components depicted in the drawings. These terms are relative concepts and are described based on the directions indicated in the drawings.

[0032] Terms such as "include" or "have" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0033] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Furthermore, terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an overly ideal or overly formal sense unless explicitly defined herein.

[0034] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0035] FIG. 1 is a cross-sectional view of an inkjet printing device according to one embodiment of the invention.

[0036] Referring to FIG. 1, an inkjet printing device (IPD) is a device that discharges ink onto a printing target using an inkjet printing method. The printing target may be, for example, a substrate (TS) of a display panel. Examples of the display panel include an organic light-emitting display panel, a micro LED display panel, a nano LED display panel, or a quantum dot light-emitting display panel. Below, as an example of a display panel, a case where a quantum dot light-emitting display panel is applied is exemplified, but it is not limited thereto, and if the same technical concept is applicable, it can be applied to other display panels.

[0037] The inkjet printing device (IPD) may include a first storage unit (RV1), a second storage unit (RV2), a first particle separation unit (PS1), a second particle separation unit (PS2), a waste ink collection module (TIC), a head unit (IH), a first pump (PU1), a second pump (PU2), a third pump (PU3), a first valve (V1), a second valve (V2), a third valve (V3), a control unit (CL), and a plurality of inlet passages (PP1, PP2, PP3, PP4, PP5, PP6, PP7, PP8, PP9).

[0038] The first storage unit (RV1) can store a first material (MT1). The first material (MT1) may include a plurality of particles (PT) and a base material (BM) in which the plurality of particles (PT) are dispersed. The second storage unit (RV2) can store a second material (MT2). ​​The second material (MT2) may be a base material.

[0039] The base material (BM) and the second material (MT2) included in the first material (MT1) may be the same material. The base material (BM) may be a solvent in which a plurality of particles (PT) are dispersed. The base material (BM) may be a medium in which dyes and / or pigments are dispersed, and may consist of various resin compositions that can generally be referred to as binders. For example, the base material (BM) may be an acrylic resin, a urethane resin, a silicone resin, or an epoxy resin, etc. However, the base material is not limited thereto. For example, depending on the type of ink, the base material (BM) may be water.

[0040] A plurality of particles (PT) may include different materials depending on the configuration formed by extruding them onto the substrate of a display panel using an inkjet printing method. For example, if the configuration formed on the substrate of the display panel is a wavelength conversion pattern, the plurality of particles (PT) may include at least one of quantum dots, quantum rods, phosphors, and scattering particles. Alternatively, if the configuration formed on the substrate of the display panel is a light transmission pattern, the plurality of particles (PT) may include scattering particles.

[0041] The first particle separation unit (PS1) can separate particles of a first predetermined size or larger among a plurality of particles (PT). The second particle separation unit (PS2) can separate particles of a second predetermined size or larger among a plurality of particles (PT). An inkjet printing device (IPD) may include a plurality of particle separation units, such as the first particle separation unit (PS1) and the second particle separation unit (PS2). The predetermined size may refer to the diameter of the particle or the width of the particle.

[0042] The first particle separation unit (PS1) and the second particle separation unit (PS2) may operate simultaneously or separately. For example, the first particle separation unit (PS1) may operate to separate particles larger than a predetermined size during the process of ink ejection. In this case, the second particle separation unit (PS2) may operate simultaneously with the first particle separation unit (PS1), or the operation of the second particle separation unit (PS2) may be stopped. Additionally, during the process where ink is not ejected, the first particle separation unit (PS1) may stop operating. In this case, the second particle separation unit (PS2) may operate to separate particles larger than a predetermined size. The operation of the second particle separation unit (PS2) can maintain the first material (MT1) in a state where it is available for ink ejection by removing particles larger than a predetermined size within the first storage unit (PS1) even when there is no ink circulation to the head unit (IH).

[0043] The concentration of particles larger than a predetermined size that move to the head unit (IH) can be reduced by a circulation process using the second particle separation unit (PS2). As a result, the amount of particles (PT) that need to be separated in the first particle separation unit (PS1) is reduced, and the purity of particles smaller than a predetermined size of the second separation material (SMT2, see FIG. 2) that move to the head unit (IH) can be increased. A detailed description of the first particle separation unit (PS1) and the second particle separation unit (PS2) will be provided later.

[0044] The waste ink collection module (TIC) can accommodate materials separated from the first particle separation unit (PS1) and the second particle separation unit (PS2). For example, the waste ink collection module (TIC) can accommodate a base material (BM) and particles of a predetermined size or larger separated from the first and second particle separation units (PS1, PS2).

[0045] The head unit (IH) can discharge material provided from the first particle separation unit (PS1) onto a printing target through at least one nozzle. Some of the material provided from the first particle separation unit (PS1) is discharged onto the printing target, and the remaining portion that is not discharged can be introduced into the first storage unit (RV1).

[0046] A plurality of inflow passages (PP1, PP2, PP3, PP4, PP5, PP6, PP7, PP8, PP9) may include a first inflow passage (PP1), a second inflow passage (PP2), a third inflow passage (PP3), a fourth inflow passage (PP4), a fifth inflow passage (PP5), a sixth inflow passage (PP6), a seventh inflow passage (PP7), an eighth inflow passage (PP8), and a ninth inflow passage (PP9).

[0047] The first inlet passage (PP1) can be connected to the first storage unit (RV1) and the first particle separation unit (PS1). The second inlet passage (PP2) can be connected to the second storage unit (RV2) and the first particle separation unit (PS1). The third inlet passage (PP3) can be connected to the first particle separation unit (PS1) and the head unit (IH). The fourth inlet passage (PP4) can be connected to the first particle separation unit (PS1) and the waste ink collection module (TIC). The fifth inlet passage (PP5) can be connected to the first storage unit (RV1) and the second particle separation unit (PS2). The sixth inlet passage (PP6) can be connected to the second storage unit (RV2) and the second particle separation unit (PS2). The seventh inlet passage (PP7) can be connected to the second particle separation unit (PS2) and the first storage unit (RV1). The 8th inlet passage (PP8) can be connected to the 2nd particle separation unit (PS2) and the waste ink collection module (TIC). The 9th inlet passage (PP9) can be connected to the head unit (IH) and the 1st storage unit (RV1).

[0048] Each of the first, second, and third pumps (PU1, PU2, PU3) can control the movement of matter. For example, the matter may move in a direction opposite to the direction of gravity or the speed of movement of the matter may be controlled by the first, second, and third pumps (PU1, PU2, PU3).

[0049] The first pump (PU1) may be located between the first storage unit (RV1) and the second particle separation unit (PS2). The second pump (PU2) may be located between the second storage unit (RV2) and the second particle separation unit (PS2). The third pump (PU3) may be located between the head unit (IH) and the first storage unit (RV1). The first pump (PU1) may supply the first material (MT1) from the first storage unit (RV1) to the second particle separation unit (PS2). The second pump (PU2) may supply the second material (MT2) from the second storage unit (RV2) to the second particle separation unit (PS2). The third pump (PU3) may supply the remaining ink that is not discharged from the head unit (IH) to the first storage unit (RV1).

[0050] The first, second, and third valves (V1, V2, V3) can control the movement of material. The first valve (V1) may be located between the first storage unit (RV1) and the first particle separation unit (PS1). The second valve (V2) may be located between the second storage unit (RV2) and the first particle separation unit (PS1). The third valve (V3) may be located between the head unit (IH) and the first storage unit (RV1).

[0051] FIG. 2a is a cross-sectional view of a first particle separation section according to one embodiment of the present invention.

[0052] Referring to FIGS. 1 and FIGS. 2a, the first particle separation unit (PS1) may be a surface acoustic wave module. The first particle separation unit (PS1) may be referred to as the first surface acoustic wave module (PS1) below. The first surface acoustic wave module (PS1) may include a first surface acoustic wave generator (IDT1) and a first internal passage (IP1). The first surface acoustic wave generator (IDT1) and the first internal passage (IP1) may be spaced apart in a first direction (DR1).

[0053] The first surface acoustic wave generating unit (IDT1) may include a piezo substrate (PZ), a first electrode (E1), and a second electrode (E2). When viewed from a second direction (DR2), the first electrode (E1) and the second electrode (E2) may overlap with the piezo substrate (PZ). The second direction (DR2) may be a direction that intersects the first direction (DR1).

[0054] The piezo substrate (PZ) may be a piezoelectric substrate. The piezoelectric substrate may include a piezoelectric material that deforms according to a driving voltage applied to the first electrode (E1) and the second electrode (E2).

[0055] The first electrode (E1) may include a first portion (WE1) and first branch portions (BE1) extending from the first portion (WE1) toward the second electrode (E2). The first portion (WE1) and the first branch portions (BE1) may have an integral shape connected to each other.

[0056] The second electrode (E2) may include a second part (WE2) and second branch parts (BE2) extending from the second part (WE2) toward the first electrode (E1). The second part (WE2) and the second branch parts (BE2) may have an integral shape connected to each other.

[0057] The first part (WE1) of the first electrode (E1) and the second part (WE2) of the second electrode (E2) may be spaced apart in a third direction (DR3). The first branch parts (BE1) and the second branch parts (BE2) may be arranged alternately, one by one, along the first direction (DR1). The third direction (DR3) may be a direction perpendicular to the plane defined by the first direction (DR1) and the second direction (DR2).

[0058] The piezo substrate (PZ) may contract or expand depending on the difference between the driving voltage applied to the first electrode (E1) and the driving voltage applied to the second electrode (E2), thereby generating a surface acoustic wave that propagates in a direction from the first surface acoustic wave generator (IDT1) toward the first internal passage (IP1). The surface acoustic wave may be a sound wave.

[0059] The first internal passage (IP1) may include a first conduit (IPP1), a second conduit (IPP2), a third conduit (IPP3), a fourth conduit (IPP4), and a first bonded conduit (IPPM1). The first bonded conduit (IPPM1) may be connected to the first conduit (IPP1), the second conduit (IPP2), the third conduit (IPP3), and the fourth conduit (IPP4).

[0060] The first conduit (IPP1) can be connected to the first inflow passage (PP1), and the second conduit (IPP2) can be connected to the second inflow passage (PP2). Accordingly, the first substance (MT1) provided from the first storage unit (RV1) can be introduced into the first conduit (IPP1) through the first inflow passage (PP1), and the second substance (MT2) provided from the second storage unit (RV2) can be introduced into the second conduit (IPP2) through the second inflow passage (PP2).

[0061] The first material (MT1) introduced through the first conduit (IPP1) and the second material (MT2) introduced through the second conduit (IPP2) may meet in the first lamination conduit (IPPM1) and mix with each other to form an ink mixture. The ink mixture may flow along the fourth direction (DR4). The fourth direction (DR4) may be the direction of gravity, but is not specifically limited thereto.

[0062] The particles (PT) contained in the first material (MT1) may have various particle diameters. For example, the particles (PT) may include raw particles and aggregated particles. Aggregated particles may be formed by some of the raw particles of a predetermined size aggregating together. The diameter (or size) of the aggregated particles may be larger than the diameter (or size) of the raw particles.

[0063] The first surface elastic wave generator (IDT1) can provide surface elastic waves to the first material (MT1) and the second material (MT2) that meet and are mixed in the first composite conduit (IPPM1) to separate the first particle (PT1) of a first predetermined size or larger and the second particle (PT2) of a first predetermined size or smaller. The first surface elastic wave generator (IDT1) can move the first particle (PT1), which has a larger particle diameter than the second particle (PT2), in the direction of surface elastic wave propagation. The second particle (PT2), which has a relatively smaller particle diameter, may be pushed almost or not pushed at all in the direction of surface elastic wave propagation compared to the first particles (PT1). The first particle (PT1) may be a clumped particle, and the second particle (PT2) may be a raw particle. The first particle (PT1) may include not only the clumped particle but also the raw particle of a size greater than the predetermined size.

[0064] In addition, as the first material (MT1) containing multiple particles (PT) flows into the area adjacent to the first surface elastic wave generator (IDT1), the first particle (PT1) can be separated from the second particle (PT2) more effectively. Therefore, the first material (MT1) can be introduced through the first conduit (IPP1) adjacent to the first surface elastic wave generator (IDT1). More specifically, the first conduit (IPP1) through which the first material (MT1) flows can be closer to the first surface elastic wave generator (IDT1) than the second conduit (IPP2) through which the second material (MT2) flows.

[0065] If the second material (MT2) is not provided to the first particle separation unit (PS1), the concentration of the second particle (PT2) contained in the second separation material (SMT2) may be higher than the concentration of the plurality of particles (PT) contained in the first material (MT1). In this embodiment, since the second material (MT2), which consists only of a base material, is provided to the first particle separation unit (PS1), the difference between the concentration of the plurality of particles (PT) contained in the first material (MT1) and the concentration of the second particle (PT2) contained in the second separation material (SMT2) may be reduced.

[0066] A second separation material (SMT2) comprising a second particle (PT2) of a first predetermined size or smaller and a base material (BMp) can be discharged through a third conduit (IPP3), and the third conduit (IPP3) can be connected to a third inlet passage (PP3). A first separation material (SMT1) comprising a first particle (PT1) of a first predetermined size or larger and a base material (BMp) can be discharged through a fourth conduit (IPP4), and the fourth conduit (IPP4) can be connected to a fourth inlet passage (PP4). The base material (BMp) may include a portion of the base material (BM) of the first material (MT1) and a portion of the second material (MT2).

[0067] A second separation material (SMT2) comprising a second particle (PT2) and a base material (BMp) can be discharged from the first particle separation unit (PS1) to the head unit (IH) through the third inlet passage (PP3). Some of the second separation material (SMT2) introduced into the head unit (IH) is discharged to a printing target, and the remaining portion that is not discharged can be discharged to the first storage unit (RV1) through the ninth inlet passage (PP9). The first separation material (SMT1) can be discharged to the waste ink collection module (TIC) through the fourth inlet passage (PP4).

[0068] Unlike the present invention, when particles of a predetermined size are separated using a filter, the contaminated filter must be removed from the equipment and disposed of, and additional work is required to replace the filter. Therefore, productivity may be reduced as the operation of the inkjet printing device is periodically stopped to replace the filter, and there is also a problem that additional processing is required to dispose of the filter.

[0069] However, according to an embodiment of the present invention, particles of a predetermined size can be separated using a surface acoustic wave module. By using a surface acoustic wave module, environmental pollution can be eliminated as filters that need to be periodically discarded are not generated. Furthermore, as filter replacement work is eliminated, costs associated with filter replacement are reduced, and productivity can be improved by extending the time available for product production.

[0070] In addition, according to an embodiment of the present invention, since the first separation materials (SMT1) are supplied to the waste ink collection module (TIC) through the fourth inlet passage (PP4), particles larger than a predetermined size do not accumulate in the first particle separation unit (PS1). Therefore, the pressure drop between the first storage unit (RV1) and the head unit (IH) can be reduced compared to the case where particles are separated using a filter. In the case of using a conventional filter, a high-capacity pump had to be used to offset the pressure drop, but according to an embodiment of the present invention, since the pressure drop is reduced or eliminated, a low-capacity pump can be used or the pump can be omitted. For example, if a pump is provided, the pump can be provided to the first and second inlet passages (PP1, PP2).

[0071] FIG. 2b is a cross-sectional view of a second particle separation unit according to an embodiment of the present invention. In describing FIG. 2b, the parts that differ from FIG. 2a are described in detail, and substantially identical components are given the same reference numerals as in FIG. 2a, and descriptions thereof are omitted.

[0072] Referring to FIG. 1 and FIG. 2b, the second particle separation unit (PS2) may be a surface acoustic wave module. The second particle separation unit (PS2) may be referred to as the second surface acoustic wave module (PS2) below. The second surface acoustic wave module (PS2) may include a second surface acoustic wave generation unit (IDT2) and a second internal passage (IP2).

[0073] The second particle separation unit (PS2) can operate for the circulation of the first material (MT1) and the second material (MT2) even when ink is not ejected from the head unit (IH). The second particle separation unit (PS2) can operate when the first particle separation unit (PS1) is operating, and the second particle separation unit (PS2) can operate even when the first particle separation unit (PS1) is not operating.

[0074] The second internal passage (IP2) may include the fifth conduit (IPP5), the sixth conduit (IPP6), the seventh conduit (IPP7), the eighth conduit (IPP8), and the second combined conduit (IPPM2). The second combined conduit (IPPM2) may be connected to the fifth conduit (IPP5), the sixth conduit (IPP6), the seventh conduit (IPP7), and the eighth conduit (IPP8).

[0075] The fifth conduit (IPP5) can be connected to the fifth inflow passage (PP5), and the sixth conduit (IPP6) can be connected to the sixth inflow passage (PP6). Accordingly, the first substance (MT1) provided from the first storage unit (RV1) can be introduced into the fifth conduit (IPP5) through the fifth inflow passage (PP5), and the second substance (MT2) provided from the second storage unit (RV2) can be introduced into the sixth conduit (IPP6) through the sixth inflow passage (PP6).

[0076] The first substance (MT1) introduced through the fifth conduit (IPP5) and the second substance (MT2) introduced through the sixth conduit (IPP6) may meet in the second lamination conduit (IPPM2) and mix with each other to form an ink mixture. The ink mixture may flow along the third direction (DR3). The third direction (DR3) may be the opposite direction to the fourth direction (DR4), that is, the opposite direction to the direction of gravity, but is not specifically limited thereto.

[0077] The second surface acoustic wave generator (IDT2) can provide surface acoustic waves to the first material (MT1) and the second material (MT2) that meet and are mixed in the second composite conduit (IPPM2) to separate the third particle (PT3) of a second predetermined size or larger and the fourth particle (PT4) of a second predetermined size or smaller. The second surface acoustic wave generator (IDT2) can move the third particle (PT3), which has a larger particle diameter than the fourth particle (PT4), in the direction of surface acoustic wave propagation. For the fourth particle (PT4), which has a relatively smaller particle diameter, it may hardly be pushed in the direction of surface acoustic wave propagation or not pushed at all compared to the third particle (PT3).

[0078] Additionally, as the first material (MT1), containing multiple particles (PT), flows into the area adjacent to the second surface elastic wave generator (IDT2), the third particle (PT3) can be effectively separated from the fourth particle (PT4). Therefore, the first material (MT1) can be introduced through the fifth conduit (IPP5) adjacent to the second surface elastic wave generator (IDT2). More specifically, the fifth conduit (IPP5), through which the first material (MT1) flows, can be closer to the second surface elastic wave generator (IDT2) than the sixth conduit (IPP6), through which the second material (MT2) flows.

[0079] A fourth separation material (SMT4) containing a base material and a fourth particle (PT4) of a second predetermined size or smaller can be discharged through a seventh conduit (IPP7), and the seventh conduit (IPP7) can be connected to a seventh inlet passage (PP7). A third separation material (SMT3) containing a base material and a third particle (PT3) of a second predetermined size or larger can be discharged through an eighth conduit (IPP8), and the eighth conduit (IPP8) can be connected to an eighth inlet passage (PP8).

[0080] The fourth separated material (SMT4) can be discharged to the first storage unit (RV1) through the seventh inlet passage (PP7), and the third separated material (SMT3) can be discharged to the waste ink collection module (TIC) through the eighth inlet passage (PP8).

[0081] Referring to FIGS. 2a and 2b, the first particle separation unit (PS1) can separate particles of a first predetermined size or larger, and the second particle separation unit (PS2) can separate particles of a second predetermined size or larger. The size of the first particle (PT1) may be greater than the first predetermined size, and the size of the third particle (PT3) may be greater than the second predetermined size. The first predetermined size and the second predetermined size may be the same or different from each other.

[0082] According to the first predetermined size and the second predetermined size, the wavelength and intensity of the elastic wave output from the first surface elastic wave generator (IDT1) and the wavelength and intensity of the elastic wave output from the second surface elastic wave generator (IDT2) can be determined. The wavelength and intensity of the elastic wave can be controlled by the control unit (CL).

[0083] For example, to separate particles larger than 2 micrometers, the wavelength of the surface acoustic wave can be adjusted to 25 micrometers or less, and the intensity of the surface acoustic wave can be adjusted to 10 dBm or more. To separate particles larger than 3 micrometers, the wavelength of the surface acoustic wave can be adjusted to 28 micrometers or less, and the intensity of the surface acoustic wave can be adjusted to 2.5 dBm or more.

[0084] FIG. 3a is a diagram illustrating the connection relationship between a first storage unit (RV1) and a first particle separation unit (PS1) according to an embodiment of the present invention. FIG. 3b is a diagram illustrating the connection relationship between a second storage unit (RV2) and a first particle separation unit (PS1) according to an embodiment of the present invention. FIG. 3c is a diagram illustrating the connection relationship between a first particle separation unit (PS1) and a head unit (IH) according to an embodiment of the present invention. FIG. 3d is a diagram illustrating the connection relationship between a first particle separation unit (PS1) and a waste ink collection module (TIC) according to an embodiment of the present invention. FIG. 3e is a diagram illustrating the connection relationship between a second particle separation unit (PS2) and a first storage unit (RV1) according to an embodiment of the present invention.

[0085] Compared to FIG. 1, each of the first particle separation units (PS1-1) shown in FIG. 3a to 3d and the second particle separation units (PS2-1) shown in FIG. 3e may be provided in multiple numbers.

[0086] Referring to FIG. 3a, the first storage unit (RV1) can be connected to a plurality of first particle separation units (PS1-1). A first material (MT1, see FIG. 1) discharged from the first storage unit (RV1) can be supplied to the plurality of first particle separation units (PS1-1) through a first inlet passage (PP1-1).

[0087] The first inlet passage (PP1-1) may include microchannels. One end of the first inlet passage (PP1-1) may be provided to a single conduit (IPC1), and the other end of the first inlet passage (PP1-1) may be provided to a plurality of branch conduits (OPC1). The first inlet passage (PP1-1) may branch from a single conduit (IPC1) into a plurality of branch conduits (OPC1). For example, a single conduit (IPC1) may be connected to a first storage unit (RV1), and a plurality of branch conduits (OPC1) may each be connected to a first particle separation unit (PS1-1). A first substance (MT1, see FIG. 1) may be introduced into a single conduit (IPC1) and provided to a plurality of first particle separation units (PS1-1) through a plurality of branch conduits (OPC1).

[0088] Referring to FIG. 3b, the second storage unit (RV2) can be connected to a plurality of first particle separation units (PS1-1). A second material (MT2, see FIG. 1) discharged from the second storage unit (RV2) can be supplied to the plurality of first particle separation units (PS1-1) through a second inlet passage (PP2-1).

[0089] The second inlet passage (PP2-1) may include microchannels. One end of the second inlet passage (PP2-1) may be provided to a single conduit (IPC2), and the other end of the second inlet passage (PP2-1) may be provided to a plurality of branch conduits (OPC2). The second inlet passage (PP2-1) may branch from a single conduit (IPC2) into a plurality of branch conduits (OPC2). For example, a single conduit (IPC2) may be connected to a second storage unit (RV2), and a plurality of branch conduits (OPC2) may each be connected to a first particle separation unit (PS1-1). A second substance (MT2, see FIG. 1) may be introduced into a single conduit (IPC2) and provided to a plurality of first particle separation units (PS1-1) through a plurality of branch conduits (OPC2).

[0090] Referring to FIG. 3c, a plurality of first particle separation units (PS1-1) can be connected to a head unit (IH). A second separated material (SMT2, see FIG. 2a) discharged from the plurality of first particle separation units (PS1-1) can be supplied to the head unit (IH) through a third inlet passage (PP3-1).

[0091] The third inlet passage (PP3-1) may include microchannels. One end of the third inlet passage (PP3-1) may be provided to a plurality of branch channels (IPC3), and the other end of the third inlet passage (PP3-1) may be provided to a single channel (OPC3). The third inlet passage (PP3-1) may be combined from the plurality of branch channels (IPC3) into a single channel (OPC3). For example, the plurality of branch channels (IPC3) may each be connected to a plurality of first particle separation units (PS1-1), and a single channel (OPC3) may be connected to a head unit (IH). A second separated material (SMT2, see FIG. 2a) discharged from the plurality of first particle separation units (PS1-1) may be introduced through the plurality of branch channels (IPC3) and provided to the head unit (IH) through the combined channel (OPC3).

[0092] Referring to FIG. 3d, a plurality of first particle separation units (PS1-1) can be connected to a waste ink collection module (TIC). A first separated material (SMT1, see FIG. 2a) discharged from the plurality of first particle separation units (PS1-1) can be supplied to the waste ink collection module (TIC) through a fourth inlet passage (PP4-1).

[0093] The fourth inlet passage (PP4-1) may include microchannels. One end of the fourth inlet passage (PP4-1) may be provided with a plurality of branch channels (IPC4), and the other end of the fourth inlet passage (PP4-1) may be provided with a single channel (OPC4). The fourth inlet passage (PP4-1) may be combined from the plurality of branch channels (IPC4) into a single channel (OPC4). For example, the plurality of branch channels (IPC4) may each be connected to a plurality of first particle separation units (PS1-1), and the single channel (OPC4) may be connected to a waste ink collection module (TIC). The first separated material (SMT1, see FIG. 2a) discharged from the plurality of first particle separation units (PS1-1) can be fed through the plurality of branched conduits (IPC4) and supplied to the waste ink collection module (TIC) through the combined conduit (OPC4).

[0094] Referring to FIG. 3e, a plurality of second particle separation units (PS2-1) can be connected to a first storage unit (RV1). A fourth separated material (SMT4, see FIG. 2b) discharged from the plurality of second particle separation units (PS2-1) can be supplied to the first storage unit (RV1) through a seventh inlet passage (PP7-1).

[0095] The seventh inlet passage (PP7-1) may include microchannels. One end of the seventh inlet passage (PP7-1) may be provided with a plurality of branch channels (IPC7), and the other end of the seventh inlet passage (PP7-1) may be provided with a single channel (OPC7). The seventh inlet passage (PP7-1) may be combined from the plurality of branch channels (IPC7) into a single channel (OPC7). For example, the plurality of branch channels (IPC7) may each be connected to a plurality of second particle separation units (PS2-1), and the single channel (OPC7) may be connected to a first storage unit (RV1). The fourth separated material (SMT4, see FIG. 2b) discharged from the plurality of second particle separation units (PS2-1) can be introduced through the plurality of branched conduits (IPC7) and supplied to the first storage unit (RV1) through the combined conduit (OPC7).

[0096] An inlet passage connected to a first storage unit (RV1) and a plurality of second particle separation units (PS2-1), which supplies a first substance (MT1, see FIG. 1) from the first storage unit (RV1) to the plurality of second particle separation units (PS2-1), may have a structure substantially identical to that illustrated in FIG. 3a. An inlet passage connected to a second storage unit (RV2) and the second particle separation units (PS2-1), which supplies a second substance (MT2, see FIG. 1) from the second storage unit (RV2) to the plurality of second particle separation units (PS2-1), may have a structure substantially identical to that illustrated in FIG. 3b. An inlet passage connected to a plurality of second particle separation units (PS2-1) and a waste ink collection module (TIC), which supplies a third separation substance (SMT3, see FIG. 2b) to the waste ink collection module (TIC), may have a structure substantially identical to that illustrated in FIG. 3d. Therefore, a description thereof is omitted.

[0097] In FIGS. 3a through 3d, eight first particle separation units (PS1-1) are illustrated as an example, and in FIG. 3e, eight second particle separation units (PS2-1) are illustrated as an example. However, the number of first particle separation units (PS1-1) and second particle separation units (PS2-1) is not limited thereto. For example, two or more first particle separation units (PS1-1) and two or more second particle separation units (PS2-1) may be provided.

[0098] Additionally, in FIGS. 3a, 3b, 3c, and 3d, the number of first particle separation units (PS1-1) and the number of second particle separation units (PS2-1) are given as examples, but are not limited thereto. For example, the number of first particle separation units (PS1-1) may be greater or less than the number of second particle separation units (PS2-1).

[0099] FIG. 4 is a cross-sectional view of an inkjet printing device according to one embodiment of the invention.

[0100] Referring to FIG. 4, an inkjet printing device (IPD-1) may include a first storage unit (RV1), a second storage unit (RV2), a first particle separation unit (PS1), a second particle separation unit (PS2), a waste ink collection module (TIC), a head unit (IH), a first supply unit (FZ1), a second supply unit (FZ2), and a plurality of inlet passages (PP1, PP2, PP3, PP4, PP5, PP6, PP7, PP8, PP9).

[0101] The first supply unit (FZ1) can supply the first substance (MT1) to the first storage unit (RV1). The second supply unit (FZ2) can supply the second substance (MT2) to the second storage unit (RV2).

[0102] When the amount of the first substance (MT1) stored in the first storage unit (RV1) is below a certain level, the first substance (MT1) can be supplied from the first supply unit (FZ1) to the first storage unit (RV1). The first supply unit (FZ1) may be an ink supply unit.

[0103] When the amount of the second substance (MT2) in the second storage unit (RV2) is below a certain level, the second supply unit (FZ2) can supply the second substance (MT2) to the second storage unit (RV2). The second supply unit (FZ2) may be a base substance supply unit.

[0104] The first particle separation unit (PS1) may be provided with a plurality of first particle separation units (PS1-1) as described in FIGS. 3a to 3d, and the second particle separation unit (PS2) may be provided with a plurality of second particle separation units (PS2-1) as described in FIG. 3e.

[0105] FIG. 5 is a cross-sectional view of an inkjet printing device according to one embodiment of the invention.

[0106] Referring to FIG. 5, the inkjet printing device (IPD-2) may include a first storage unit (RV1), a first particle separation unit (PS1), a second particle separation unit (PS2), a waste ink collection module (TIC), a head unit (IH), and a plurality of inlet passages (PP1, PP3, PP4, PP5, PP7, PP8, PP9).

[0107] The first storage unit (RV1) can store the first material (MT1). The first material (MT1) may include a plurality of particles (PT) and a base material (BM) in which the plurality of particles (PT) are dispersed.

[0108] The inkjet printing device (IPD-2) may not include a second storage unit (RV2, see FIG. 1). Without supplying a second material (MT2, see FIG. 2), the first particle separation unit (PS1) and the second particle separation unit (PS2) can separate particles of a predetermined size or larger from the first material (MT1) introduced from the first storage unit (RV1).

[0109] The first particle separation unit (PS1) may be provided with a plurality of first particle separation units (PS1-1) as described in FIGS. 3a to 3d, and the second particle separation unit (PS2) may be provided with a plurality of second particle separation units (PS2-1) as described in FIG. 3e.

[0110] FIG. 6 is a cross-sectional view of an inkjet printing device according to one embodiment of the invention.

[0111] Referring to FIG. 6, the inkjet printing device (IPD-3) may include a first storage unit (RV1), a concentration meter (CM), a base material supply unit (BMFZ), a first particle separation unit (PS1), a second particle separation unit (PS2), a waste ink collection module (TIC), a head unit (IH), and a plurality of inlet passages (PP1, PP3, PP4, PP5, PP7, PP8, PP9).

[0112] The concentration meter (CM) can measure the concentration of the second separated substance (SMT2-1) moving from the head section (IH) to the first storage section (RV1). The concentration meter (CM) can be located between the ninth inlet passage (PP9) connecting the head section (IH) and the first storage section (RV1).

[0113] The base material supply unit (BMFZ) can be connected to the first storage unit (RV1). The base material supply unit (BMFZ) can supply the base material (BM) to the first storage unit (RV1). For example, the base material (BM) can be supplied according to the concentration of particles contained in the second separated material (SMT2-1) measured by the concentration meter (CM).

[0114] The inkjet printing device (IPD-3) can discharge the first and third particles (PT1, PT3, see FIG. 2a and 2b) among the first to fourth particles (PT1, PT2, PT3, PT4, see FIG. 2a and 2b) to the waste ink collection module (TIC) and discharge the second and fourth particles (PT2, PT4, see FIG. 2a and 2b) to the head unit (IH). In this case, some of the base material (BM) may be discharged to the waste ink collection module (TIC), and other parts of the base material (BM) may be discharged to the head unit (IH). Accordingly, as the operation of the first particle separation unit (PS1) and the second particle separation unit (PS2) continues, the concentration of particles contained in the second separation material (SMT2-1) provided through the head unit (IH) may change.

[0115] If the concentration of particles (PT) contained in the second separated material (SMT2-1) measured by the concentration meter (CM) falls outside the reference concentration range, the base material supply unit (BMFZ) can supply base material (BM) to the first storage unit (RV1) to maintain the reference concentration range. If the concentration of particles (PT) measured by the concentration meter (CM) falls within the reference concentration range, the base material supply unit (BMFZ) may not supply base material (BM) to the first storage unit (RV1).

[0116] The first particle separation unit (PS1) may be provided with a plurality of first particle separation units (PS1-1) as described in FIGS. 3a to 3d, and the second particle separation unit (PS2) may be provided with a plurality of second particle separation units (PS2-1) as described in FIG. 3e.

[0117] FIG. 7 is a cross-sectional view of an inkjet printing device according to one embodiment of the invention.

[0118] Referring to FIG. 7, the inkjet printing device (IPD-4) may include a first storage unit (RV1), a first particle separation unit (PS1), a second particle separation unit (PS2), a waste ink collection module (TIC), a crushing unit (CP), a head unit (IH), and a plurality of inlet passages (PP1, PP3, PP4, PP5, PP7, PP8, PP9, PP10).

[0119] The first particle (PT1, see FIG. 2a) contained in the first separated material (SMT1, see FIG. 2a) and the third particle (PT3, see FIG. 2b) contained in the third separated material (SMT3, see FIG. 2b) stored in the waste ink collection module (TIC) can be crushed in the crushing unit (CP). The crushing unit (CP) can be connected to the waste ink collection module (TIC) and can be connected to the first storage unit (RV1) through the 10th inlet passage (PP10).

[0120] In the grinding section (CP), the first particle (PT1, see FIG. 2a) and the third particle (PT3, see FIG. 2b) can be ground to a size smaller than that of the second particle (PT2, see FIG. 2a) and the fourth particle (PT4, see FIG. 2b). The ground particles, with reduced particle size, can be introduced into the first storage section (RV1) through the tenth inlet passage (PP10). Although FIG. 7 illustrates an example where the grinding section (CP) supplies the ground particles directly to the first storage section (RV1), the present invention is not limited thereto.

[0121] Waste ink recycling can be made possible through the crushing process in the crushing unit (CP). Therefore, environmental pollution caused by ink disposal can be reduced, and ink disposal costs can be reduced. The crushing unit (CP) described in Fig. 7 can also be applied to the inkjet printing devices (IPD, IPD-1, IPD-2, IPD-3) described earlier with reference to Figs. 1, 4, 5, and 6.

[0122] The first particle separation unit (PS1) may be provided with a plurality of first particle separation units (PS1-1) as described in FIGS. 3a to 3d, and the second particle separation unit (PS2) may be provided with a plurality of second particle separation units (PS2-1) as described in FIG. 3e.

[0123] FIG. 8a is a flowchart of a method for manufacturing a display device according to an embodiment of the present invention. FIG. 8b is a flowchart illustrating the operation of a first particle separation unit (PS1) according to an embodiment of the present invention. FIG. 8c is a flowchart illustrating the operation of a second particle separation unit (PS2) according to an embodiment of the present invention.

[0124] Referring to FIGS. 1, FIGS. 2a, FIGS. 2b, and FIGS. 8a, a base material (BM) and a plurality of particles (PT) stored in a storage unit may be provided to a first particle separation unit (PS1) and a second particle separation unit (PS2) (S100). The storage unit may include a first storage unit (RV1) and a second storage unit (RV2). In one embodiment of the present invention, the storage unit may include only the first storage unit (RV1, see FIGS. 5, 6, or 7).

[0125] Particles of a size larger than a predetermined size (or reference size) can be removed by the first particle separation unit (PS1) and the second particle separation unit (PS2) (S200). The size of the first particle (PT1) of a size larger than a predetermined size separated by the first particle separation unit (PS1) and the size of the third particle (PT3) of a size larger than a second predetermined size separated by the second particle separation unit (PS2) may be the same or different.

[0126] The first particle separation unit (PS1) and the second particle separation unit (PS2) may operate simultaneously or selectively. For example, when the first particle separation unit (PS1) is not operating, the second particle separation unit (PS2) may be operated. That is, even when the ink ejection operation is not in progress, the material stored in the storage unit may be circulated by the second particle separation unit (PS2), and particles of a predetermined size may be separated. Additionally, when the first particle separation unit (PS1) is operating, the second particle separation unit (PS2) may operate simultaneously with the first particle separation unit (PS1) or stop operating.

[0127] Ink from which particles larger than a predetermined size have been removed can be supplied to the head unit (IH) (S300). The fourth separated material (SMT4) from which the third particle (PT3) has been removed can be introduced into the storage unit. For example, the fourth separated material (SMT4) can be introduced back into the first storage unit (RV1) of the storage unit. The second separated material (SMT2) from which the first particle (PT1) has been removed can be supplied to the head unit (IH) through the third inflow passage (PP3).

[0128] Ink introduced into the head unit (IH) can be discharged onto the substrate (TS) (S400). The head unit (IH) may include at least one nozzle. The ink can be discharged onto the substrate (TS) through the nozzle. Ink remaining in the head unit (IH) without being discharged can be introduced into the first storage unit (RV1) through the ninth inflow channel (PP9).

[0129] Referring to FIGS. 1, FIGS. 2a, FIGS. 2b, and FIGS. 8b, a base material (BM) and a plurality of particles (PT) stored in a storage unit can be introduced into a first particle separation unit (PS1) (S210-1).

[0130] A first particle (PT1) having a size greater than or equal to a first predetermined size among a plurality of particles (PT) and a second particle (PT2) having a size less than the first predetermined size among a plurality of particles (PT) can be separated by a surface elastic wave (S220-1). The first predetermined size can be determined by the wavelength and intensity of the elastic wave output from the first surface elastic wave generator (IDT1). The wavelength and intensity of the elastic wave can be controlled by a control unit (CL).

[0131] A first separation material (SMT1) containing a first particle (PT1) can be provided to a waste ink collection module (TIC). A second separation material (SMT2) from which the first particle (PT1) has been removed can be provided to a head unit (IH) (S230-1).

[0132] Referring to FIGS. 1, 2 and 8c, a base material (BM) and a plurality of particles (PT) stored in a storage unit can be introduced into a second particle separation unit (PS2) (S210-2).

[0133] A third particle (PT3) having a size greater than or equal to a second predetermined size among a plurality of particles (PT) and a fourth particle (MT4) having a size less than or equal to a second predetermined size among a plurality of particles (PT) can be separated by a surface elastic wave (S220-2). The second predetermined size can be determined by the wavelength and intensity of the elastic wave output from the second surface elastic wave generator (IDT2). The wavelength and intensity of the elastic wave can be controlled by a control unit (CL).

[0134] The third separation material (SMT3) containing the third particle (PT3) can be provided to a waste ink collection module (TIC). The fourth separation material (SMT4) from which the third particle (PT3) has been removed can be provided to a storage unit (S230-2).

[0135] FIG. 9 is a cross-sectional view illustrating a display device formed according to one embodiment of the present invention.

[0136] Referring to FIG. 9, the display panel (DP) may be a configuration that substantially generates an image. The display panel (DP) may be a light-emitting display panel or a light-receiving display panel. For example, the display panel (DP) may be any one of an organic light-emitting display panel, a quantum dot light-emitting display panel, a micro LED display panel, a nano LED display panel, a liquid crystal display panel, an electrophoretic display panel, an electrowetting display panel, and a MEMS display panel, and is not particularly limited.

[0137] A display panel (DP) may include a first substrate (100, or lower substrate) and a second substrate (200, or upper substrate) spaced apart from and facing the first substrate (100). A predetermined cell gap may be formed between the first substrate (100) and the second substrate (200). The cell gap may be maintained by a sealant that joins the first substrate (100) and the second substrate (200). An insulating material may be filled into the cell gap.

[0138] The first substrate (100) may include a first base substrate (BS1), a circuit element layer (DP-CL), a display element layer (DP-OLED), and an upper insulating layer (TFL). The stacked structure of the first substrate (100) is not particularly limited. The circuit element layer (DP-CL) may be disposed on the first base substrate (BS1). The circuit element layer (DP-CL) may include a plurality of insulating layers, a plurality of conductive layers, and a semiconductor layer. The display element layer (DP-OLED) may be disposed on the circuit element layer (DP-CL). The upper insulating layer (TFL) is disposed on the display element layer (DP-OLED) and may seal the display element layer (DP-OLED).

[0139] The first substrate (100) may include a plurality of insulating layers and a semiconductor pattern, a conductive pattern, a signal line, etc. An insulating layer, a semiconductor layer, and a conductive layer are formed by methods such as coating or deposition. Subsequently, the insulating layer, the semiconductor layer, and the conductive layer can be selectively patterned by photolithography. In this way, the semiconductor pattern, the conductive pattern, the signal line, etc. included in the circuit element layer (DP-CL) and the display element layer (DP-OLED) are formed.

[0140] The first base substrate (BS1) may be a silicon substrate, a plastic substrate, a glass substrate, an insulating film, or a laminated structure including a plurality of insulating layers. In this embodiment, the circuit element layer (DP-CL) may include a buffer film (BFL), a first insulating layer (10), a second insulating layer (20), and a third insulating layer (30).

[0141] The buffer film (BFL) may be a barrier layer that protects the lower surfaces of the active (AD), source (SD), and drain (DD). In this case, the buffer film (BFL) may block contamination or moisture, etc., introduced through the first base substrate (BS1) itself or through the first base substrate (BS1) from penetrating into the active (AD), source (SD), and drain (DD). Alternatively, the buffer film (BFL) may be a light-blocking layer that blocks external light incident through the first base substrate (BS1) from entering the active (AD). In this case, the buffer film (BFL) may further include a light-blocking material.

[0142] FIG. 9 illustrates an exemplary arrangement of the active (AD), source (SD), drain (DD), and gate (GD) constituting the driving transistor (TD). The active (AD), source (SD), and drain (DD) may be regions distinguished according to the doping concentration or conductivity of the semiconductor pattern.

[0143] The first insulating layer (10) is placed on the buffer membrane (BFL) and can cover the active (AD), source (SD), and drain (DD). The first insulating layer (10) may include an inorganic material. The inorganic material may include at least one of silicon nitride, silicon oxynitride, silicon oxide, titanium oxide, and aluminum oxide.

[0144] A gate (GD) may be placed on the first insulating layer (10). A second insulating layer (20) may be placed on the first insulating layer (10) and may cover the gate (GD). The second insulating layer (20) may be composed of a single layer or multiple layers. For example, the single layer may include an inorganic layer. The multiple layers may include an organic layer and an inorganic layer.

[0145] A third insulating layer (30) may be placed on top of a second insulating layer (20). The third insulating layer (30) may be composed of a single layer or multiple layers. For example, the single layer may include an organic layer. The multiple layers may include an organic layer and an inorganic layer. The third insulating layer (30) may be a flattening layer that provides a flat surface on top.

[0146] A display element layer (DP-OLED) may be disposed on a third insulating layer (30). The display element layer (DP-OLED) may include a light-emitting element (OLED) and a pixel defining layer (PDL). In this embodiment, the light-emitting elements (OLED) may be organic light-emitting diodes, but are not limited thereto. For example, the light-emitting elements (OLED) may be micro-LED elements or nano-LED elements. The pixel defining layer (PDL) may be an organic layer.

[0147] Light-emitting elements (OLEDs) can generate source light. The light-emitting element (OLED) may include a first electrode (AE), a hole control layer (HCL), a light-emitting layer (EML), an electronic control layer (ECL), and a second electrode (CE).

[0148] The first electrode (AE) is placed on the third insulating layer (30). The first electrode (AE) is connected directly or indirectly to the driving transistor (TD), and the connection structure between the first electrode (AE) and the driving transistor (TD) is not shown in FIG. 9. A light-emitting opening (OP) is defined in the pixel defining film (PDL). The light-emitting opening (OP) exposes at least a portion of the first electrode (AE). The light-emitting opening (OP) can define light-emitting regions corresponding to pixel regions (PXA) on the first substrate (100). Here, "corresponds" means to overlap and is not limited to the same area.

[0149] The hole control layer (HCL), the light-emitting layer (EML), and the electronic control layer (ECL) can be placed commonly in the pixel region (PXA) and the peripheral region (NPXA). The hole control layer (HCL), the light-emitting layer (EML), and the electronic control layer (ECL) can be placed commonly in the pixel regions (PXA).

[0150] A hole control layer (HCL) may be disposed on the first electrode (AE). The hole control layer (HCL) includes a hole transport layer and may further include a hole injection layer. An emission layer (EML) may be disposed on the hole control layer (HCL).

[0151] The emitting layer (EML) can generate blue light as a source light. The blue light may include wavelengths ranging from 410 nm to 480 nm. The emission spectrum of the blue light may have a peak wavelength in the range of 440 nm to 460 nm. The emitting layer (EML) may be placed independently in the pixel regions (PXA). Being placed independently means that the pixel region (PXA) is separated from the emitting layer (EML). However, it is not limited thereto, and the emitting layer (EML) may be placed commonly in the pixel region (PXA) and may be placed commonly in the pixel region (PXA) and the surrounding region (NPXA).

[0152] An electronic control layer (ECL) may be placed on top of an emissive layer (EML). The electronic control layer (ECL) includes an electron transport layer and may further include an electron injection layer. The electronic control layer (ECL) may be placed in common in the pixel area (PXA) and the peripheral area (NPXA).

[0153] The second electrode (CE) can be placed on the electronic control layer (ECL). The second electrode (CE) can be placed in common in the pixel area (PXA) and the peripheral area (NPXA).

[0154] The upper insulating layer (TFL) may be placed on the second electrode (CE). The upper insulating layer (TFL) may contain an organic or inorganic material. The upper insulating layer (TFL) may have a multilayer structure in which an inorganic layer and an organic layer are repeated. The upper insulating layer (TFL) may have a sealed structure of an inorganic layer, an organic layer, and an inorganic layer.

[0155] A second substrate (200) may be placed on a first substrate (100). The second substrate (200) may include a second base substrate (BS2), a color filter (CF), an optical pattern (CCF), a partition wall (BW), a partition opening (BW-OP), and a partition pattern (BP).

[0156] The second base substrate (BS2) may be a silicon substrate, a plastic substrate, a glass substrate, an insulating film, or a laminated structure comprising a plurality of insulating layers (200-1, 200-2, 200-3). The plurality of insulating layers (200-1, 200-2, 200-3) may be organic layers or inorganic layers.

[0157] The segmented pattern (BP) may be disposed on the lower surface of the second base substrate (BS2) and may be disposed in the peripheral region (NPXA). The segmented pattern (BP) may have a multilayer structure. The first layer (BP-1) may include a material identical to a color filter that transmits blue light. The second layer (BP-2) may include a conventional black coloring agent. The second layer (BP-2) may include a black dye or a black pigment mixed in the base resin. In one embodiment, the black coloring agent may include carbon black, or a metal such as chromium or an oxide thereof. The second layer (BP-2) may be, for example, a black matrix.

[0158] A color filter (CF) may be superimposed on a pixel area (PXA). The color filter (CF) transmits light within a specific wavelength range and blocks light outside that wavelength range. Each color filter (CF) comprises a base resin and a dye and / or pigment dispersed in the base resin. The base resin is a medium in which the dye and / or pigment is dispersed and may consist of various resin compositions that can generally be referred to as a binder. The color filter (CF) may be a color filter that transmits red light (or a red color filter), a color filter that transmits green light (or a green color filter), or a color filter that transmits blue light (or a blue color filter).

[0159] A color filter (CF) may be disposed on one side of the second base substrate (BS2). For example, a color filter (CF) may be disposed on the lower surface of the second base substrate (BS2). The color filter (CF) may be disposed in the peripheral area (NPXA) and the pixel area (PXA). A first insulating layer (200-1) is disposed below the color filter (CF). A second insulating layer (200-2) providing a flat surface may be disposed below the first insulating layer (200-1). The first insulating layer (200-1) may be an inorganic film, and the second insulating layer (200-2) may be an organic film. Even if the same terms are used in this specification, it is clear that the first to third insulating layers (200-1, 200-2, 200-3) of the second substrate (200) are distinguished from the first to third insulating layers (10, 20, 30) of the circuit element layer (DP-CL) described above.

[0160] A partition wall (BW) is disposed on the lower side of the second insulating layer (200-2). In this embodiment, the partition wall (BW) may include a base resin with high light transmittance and an additive. The base resin may consist of various resin compositions that can generally be referred to as binders. The additive may include a coupling agent and / or a photoinitiator. The additive may further include a dispersant.

[0161] A partition wall (BW) can be placed below a color filter (CF). A partition aperture (BW-OP) corresponding to a pixel area (PXA) can be defined in the partition wall (BW).

[0162] An optical pattern (CCF) can be placed between a color filter (CF) and a light-emitting element (OLED). An optical pattern (CCF) can be placed inside a split aperture (BW-OP). The optical pattern (CCF) receives source light from an emitting layer (EML) and can provide light of a predetermined color. For example, the optical pattern (CCF) can be a wavelength conversion pattern or a light transmission pattern.

[0163] When the optical pattern (CCF) is a wavelength conversion pattern, the optical pattern (CCF) may include a base resin and quantum dots mixed (or dispersed) in the base resin. In this case, the optical pattern (CCF) may further include scattering particles mixed in the base resin. The scattering particles may be titanium oxide (TiO2) or silica-based nanoparticles, etc. In this case, the optical pattern (CCF) may receive source light and output light of a different color from the source light, for example, red light or green light.

[0164] The base resin serves as a medium in which quantum dots are dispersed and may consist of various resin compositions that can generally be referred to as binders. However, it is not limited thereto; any medium capable of dispersing quantum dots in this specification may be referred to as a base resin regardless of its name, additional functions, constituent materials, etc. The base resin may be a polymer resin. For example, the base resin may be an acrylic resin, a urethane resin, a silicone resin, an epoxy resin, etc. The base resin may be a transparent resin. Quantum dots may be particles that convert the wavelength of incident light. Quantum dots are materials with a crystal structure of several nanometers in size, composed of hundreds to thousands of atoms, and exhibit a quantum confinement effect in which the energy band gap increases due to their small size. When light with a wavelength having energy higher than the band gap is incident on quantum dots, the quantum dots absorb the light to become excited, and then fall back to the ground state while emitting light of a specific wavelength. The energy of the emitted light has a value corresponding to the band gap. Quantum dots can have their luminescence characteristics due to quantum confinement effects controlled by adjusting their size and composition.

[0165] When the optical pattern (CCF) is a light transmission pattern, the optical pattern (CCF) may include a base resin and scattering particles mixed in the base resin. In this case, the optical pattern (CCF) receives source light and can output light of the same color as the source light.

[0166] The third insulating layer (200-3) may be an inorganic film that seals the partition wall (BW) and the optical pattern (CCF).

[0167] Figure 10 is a drawing illustrating some of the processes of the manufacturing method of the display panel shown in Figure 9.

[0168] Referring to FIGS. 9 and 10, a head portion (IH) of an inkjet printing device (IPD, see FIG. 1) is illustrated. The head portion (IH) may include at least one nozzle (NZ). The inkjet printing device (IPD, see FIG. 1) may discharge ink (INK) onto a substrate (TS) through the nozzle (NZ). The ink (INK) may be a second separated material (SMT2, see FIG. 2a) from which particles larger than a predetermined size among a plurality of particles (PT) have been removed.

[0169] An optical pattern (CCF) can be formed on the inner side of a split aperture (BW-OP) using an inkjet printing device (IPD, see FIG. 1). If the optical pattern (CCF) is a wavelength conversion pattern, the ink (INK) may include a base resin and quantum dots mixed (or dispersed) in the base resin. Alternatively, if the optical pattern (CCF) is a light transmission pattern, the ink may include a base resin and scattering particles mixed (or dispersed) in the base resin.

[0170] FIGS. 9 and 10 illustrate an exemplary example of forming an optical pattern (CCF) using an inkjet printing device (IPD, see FIG. 1), but the configurations that can be formed using the inkjet printing device (IPD, see FIG. 1) are not limited to the above examples. For example, if the display panel is a nano LED display panel, the light-emitting layer of the nano LED display panel can be formed using an inkjet printing device (IPD, see FIG. 1). In this case, the ink (INK) may include nano-sized LED chips mixed (or dispersed) in a solvent (e.g., water).

[0171] Although the present invention has been described above with reference to preferred embodiments, those skilled in the art or those with ordinary knowledge in the relevant technical field will understand that various modifications and changes can be made to the invention without departing from the spirit and technical scope of the invention as set forth in the claims below. Accordingly, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be determined by the claims. Explanation of the symbols

[0172] IPD: Inkjet printing device RV1: First storage unit RV2: Second storage unit PS1: First particle separation unit PS2: Second particle separation unit TIC: Waste ink collection module IH: Head unit CL: Control unit MT1: First substance MT2: Second substance

Claims

Claim 1 An inkjet printing device comprising: a head unit including a nozzle for discharging ink; a waste ink collection module; a first storage unit storing a first material including a plurality of particles; a first particle separation unit into which the first material discharged from the first storage unit is introduced, and which discharges a first separation material including a first particle of a first predetermined size or larger among the plurality of particles to the waste ink collection module, and discharges a second separation material including a second particle of a second size or smaller among the plurality of particles to the head unit; and a second particle separation unit into which the first material discharged from the first storage unit is introduced, and which discharges a third separation material including a third particle of a second predetermined size or larger among the plurality of particles to the waste ink collection module, and which discharges a fourth separation material including a fourth particle of a second predetermined size or smaller among the plurality of particles to the first storage unit, wherein each of the first particle separation unit and the second particle separation unit is a surface acoustic wave module. Claim 2 An inkjet printing device according to claim 1, further comprising a second storage unit in which a second substance is stored, wherein the first substance and the second substance are introduced into each of the first particle separation unit and the second particle separation unit. Claim 3 In claim 2, the first material further comprises a base material in which the plurality of particles are dispersed, and the second material is an inkjet printing device composed of the base material. Claim 4 An inkjet printing device according to claim 2, wherein the first particle separation unit comprises a first internal passage and a first surface elastic wave generating unit adjacent to the first internal passage, and the second particle separation unit comprises a second internal passage and a second surface elastic wave generating unit adjacent to the second internal passage. Claim 5 In claim 4, the first internal passage comprises a first conduit connected to the first storage unit, a second conduit connected to the second storage unit, a third conduit connected to the head unit, and a fourth conduit connected to the waste ink collection module, and the second internal passage comprises a fifth conduit connected to the first storage unit and into which the first substance flows, a sixth conduit connected to the second storage unit, a seventh conduit connected to the first storage unit and into which the fourth separated substance is discharged, and an eighth conduit connected to the waste ink collection module. Claim 6 An inkjet printing device according to claim 4, further comprising a control unit for controlling the wavelength and intensity of each of the first surface acoustic wave and the second surface acoustic wave. Claim 7 An inkjet printing device according to claim 2, further comprising: a first supply unit for supplying the first substance to the first storage unit; and a second supply unit for supplying the second substance to the second storage unit. Claim 8 An inkjet printing device according to claim 2, further comprising: a first pump disposed between the first storage unit and the second particle separation unit for moving the first substance; and a second pump disposed between the second storage unit and the second particle separation unit for moving the second substance. Claim 9 An inkjet printing device according to claim 1, wherein the first particle separation unit is provided in plurality and the second particle separation unit is provided in plurality. Claim 10 An inkjet printing device according to claim 1, further comprising a valve disposed between the first storage unit and the first particle separation unit to control the movement of the first material. Claim 11 An inkjet printing device according to claim 1, further comprising a pump disposed between the head portion and the first storage portion for moving the second separated material, wherein the head portion discharges a portion of the second separated material to the first storage portion. Claim 12 An inkjet printing device according to claim 1, further comprising a valve disposed between the head portion and the first storage portion to control the movement of the second separated material. Claim 13 An inkjet printing device according to claim 1, further comprising: a concentration measuring unit for measuring the concentration of the second separated substance moving from the head unit to the first storage unit; and a base material supply unit for providing a base material to the first storage unit based on the concentration. Claim 14 An inkjet printing device according to claim 1, further comprising a grinding unit for grinding the first particle contained in the first separation material and the third particle contained in the third separation material stored in the waste ink collection module. Claim 15 An inkjet printing device comprising: a first storage unit storing a first material comprising a plurality of particles and a base material in which the plurality of particles are dispersed; a second storage unit storing the base material; a first particle separation unit into which the first material discharged from the first storage unit and the base material discharged from the second storage unit are introduced, and which separates a first particle of a first predetermined size or larger among the plurality of particles; a second particle separation unit into which the first material discharged from the first storage unit and the base material discharged from the second storage unit are introduced, and which separates a third particle of a second predetermined size or larger among the plurality of particles; a waste ink collection module receiving the first particle and the third particle; and a head unit into which ink from which the first particle and the third particle have been removed from the first material and the base material is introduced. Claim 16 In claim 15, the inkjet printing device wherein each of the first particle separation unit and the second particle separation unit is a surface acoustic wave module. Claim 17 A method for manufacturing a display device comprising: a step of providing a base material and a plurality of particles stored in a storage unit to a first particle separation unit; a step of providing the base material and the plurality of particles stored in the storage unit to a second particle separation unit; a step of separating the plurality of particles introduced into the first particle separation unit into a first particle having a size greater than or equal to a first predetermined size and a second particle having a size less than or equal to the first predetermined size using surface elastic waves; a step of separating the plurality of particles introduced into the second particle separation unit into a third particle having a size greater than or equal to a second predetermined size and a fourth particle having a size less than or equal to the second predetermined size using surface elastic waves; and a step of discharging the ink from which the first particle and the third particle have been removed onto a substrate using a head unit. Claim 18 A method for manufacturing a display device according to claim 17, wherein the step of separating the first particle and the second particle comprises: providing the first particle to a waste ink collection module; and providing the second particle to the head unit, and the step of separating the third particle and the fourth particle comprises: providing the third particle to the waste ink collection module; and providing the fourth particle to the storage unit. Claim 19 A method for manufacturing a display device according to claim 18, wherein the storage unit comprises: a first storage portion in which a portion of the base material and the plurality of particles are stored; and a second storage portion in which a portion of the base material is stored, wherein each of the first particle separation portion and the second particle separation portion receives the base material and the plurality of particles from the first storage portion and the second storage portion. Claim 20 A method for manufacturing a display device according to claim 17, wherein each of the steps of separating the first particle and the second particle, and separating the third particle and the fourth particle, comprises the step of adjusting the wavelength and intensity of the surface elastic wave according to the first predetermined size or the second predetermined size.

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