Inkjet printing apparatus

Abstract

The present invention relates to an inkjet printing device. An inkjet printing device according to one embodiment comprises a stage and an inkjet head having a plurality of nozzles for discharging ink containing a plurality of particles, the inkjet head comprising a base portion constituting the main body of the inkjet head, a discharge portion disposed adjacent to the base portion and having the plurality of nozzles disposed therein, and an internal flow path through which the ink is supplied between the base portion and the discharge portion, wherein the base portion comprises a first surface in contact with the internal flow path, and at least a portion of the first surface has an incline.

Description

Technology Field

[0001] The present invention relates to an inkjet printing device. Background Technology

[0002] The importance of display devices is increasing along with the development of multimedia. In response to this, various types of display devices, such as Organic Light Emitting Displays (OLEDs) and Liquid Crystal Displays (LCDs), are being used.

[0003] A device for displaying images of a display device includes a display panel such as an organic light-emitting display panel or a liquid crystal display panel. Among these, as a light-emitting display panel, it may include a light-emitting element; for example, in the case of a light-emitting diode (LED), there are organic light-emitting diodes (OLEDs) that use organic materials as light-emitting materials, and inorganic light-emitting diodes that use inorganic materials as light-emitting materials.

[0004] Meanwhile, an inkjet printing device may be used to form an organic layer included in a display device or to form an inorganic light-emitting diode. After printing any ink or solution with an inkjet, a post-processing step may be performed to transfer the inorganic light-emitting diode element or to form an organic layer. The inkjet printing device may supply a predetermined ink or solution to an inkjet head, and the inkjet head may perform a process of spraying the ink or solution onto a substrate to be processed (e.g., a target substrate). The problem to be solved

[0005] The problem that the present invention aims to solve is to provide an inkjet printing device that prevents the sedimentation of particles remaining in the print head unit and makes the number of particles in the ink uniform.

[0006] In addition, another problem that the present invention aims to solve is to provide an inkjet printing device that can prevent stains caused by differences in brightness of the display device.

[0007] The problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0008] An inkjet printing device according to one embodiment for solving the above problem comprises a stage and an inkjet head having a plurality of nozzles for discharging ink containing a plurality of particles, the inkjet head comprising a base portion constituting the main body of the inkjet head, a discharge portion disposed adjacent to the base portion and having the plurality of nozzles disposed therein, and an internal flow path through which the ink is supplied between the base portion and the discharge portion, wherein the base portion comprises a first surface in contact with the internal flow path, and at least a portion of the first surface may have an incline.

[0009] Between the first surface of the base portion and the discharge portion, there is a first distance from one point on the first surface to the discharge portion in a direction perpendicular to the discharge portion, and a second distance from another point on the first surface to the discharge portion, and the first distance may be longer than the second distance.

[0010] The inkjet head further includes an inlet through which the ink is supplied to the internal flow path and an outlet through which the ink is discharged, and the first distance may be adjacent to the inlet and the second distance may be adjacent to the outlet.

[0011] The above second distance may be 90% to 99% of the above first distance.

[0012] The distance between the first surface and the discharge part can be gradually reduced as one side of the first surface of the base part moves from one side to the other.

[0013] The plurality of nozzles includes a first nozzle adjacent to the inlet and a second nozzle adjacent to the outlet, and the diameter of the first nozzle may be larger than the diameter of the second nozzle.

[0014] The diameter of the second nozzle may be 90% to 99% of the diameter of the first nozzle.

[0015] The plurality of nozzles described above further include a third nozzle disposed between the first nozzle and the second nozzle and adjacent to the second nozzle, wherein the diameter of the third nozzle may be larger than that of the second nozzle and smaller than that of the first nozzle.

[0016] The diameter of the internal channel adjacent to the outlet may be smaller than the diameter of the internal channel adjacent to the inlet.

[0017] The diameter of the internal channel adjacent to the outlet may gradually decrease as it approaches the outlet.

[0018] Additionally, an inkjet printing device according to one embodiment includes a stage and an inkjet head having a plurality of nozzles located above the stage and ejecting ink containing a plurality of particles, wherein the inkjet head may include a base portion constituting the main body of the inkjet head, an ejection portion disposed adjacent to the base portion and having the plurality of nozzles disposed therein, an internal flow path through which the ink is supplied between the base portion and the ejection portion, and at least one rotating member that rotates within the internal flow path to mix the ink.

[0019] The above-mentioned rotating member may include a rotating shaft fixed to the base portion and a blade coupled to the rotating shaft and rotating in one direction.

[0020] The length of the above wing may be shorter than the length from the rotation axis to one side of the base part.

[0021] The above-mentioned rotating member may be included in a plurality of units, and the rotating member may include a first rotating member and a second rotating member that is smaller in size than the first rotating member.

[0022] The first rotating member may be positioned at the center of the base portion, and the second rotating member may be positioned at at least one corner of the base portion.

[0023] Additionally, an inkjet printing device according to one embodiment includes a stage and an inkjet head having a plurality of nozzles that discharge ink containing a plurality of particles, the inkjet head having a base portion constituting the main body of the inkjet head, a discharge portion disposed adjacent to the base portion and having the plurality of nozzles disposed therein, an internal flow path through which the ink is supplied between the base portion and the discharge portion, and a side wall portion disposed adjacent to the base portion with the internal flow path in between and forming the side wall of the internal flow path, and may include a sedimentation prevention member that causes the plurality of particles mixed in the ink to flow on at least one surface of the side wall portion.

[0024] The inkjet head further includes an inlet through which the ink is supplied to the internal flow path and an outlet through which the ink is discharged, and the side wall may include a first side wall extending from the discharge portion and contacting the inlet, and a second side wall extending from the discharge portion and contacting the outlet.

[0025] The above sedimentation prevention member is inserted and disposed in at least one of the first sidewall portion and the second sidewall portion, and a portion may be exposed to the internal flow path.

[0026] The above sedimentation prevention member may include an ultrasonic vibrator.

[0027] The above sediment prevention member may include a charged plate to which voltage is applied.

[0028] Specific details of other embodiments are included in the detailed description and drawings. Effects of the invention

[0029] According to the inkjet printing device of the embodiments, by forming a slope on one surface of the base portion, the flow rate of the ink in the internal flow path adjacent to the outlet is prevented from decreasing, so that particles are not settled and can be discharged in a uniform number through the nozzles.

[0030] In addition, according to the inkjet printing device of the embodiment, the inkjet head includes a rotating member so that a plurality of particles contained in the ink can be mixed and discharged in a uniform number through the nozzles without settling in the internal flow path.

[0031] In addition, according to the inkjet printing device of the embodiment, the inkjet head includes a sedimentation prevention member, so that a plurality of particles contained in the ink are dispersed so that the particles do not settle in the internal flow path and can be discharged in a uniform number through the nozzles.

[0032] According to the inkjet printing device according to the above-described embodiments, the number of particles per unit droplet of ink is made uniform, thereby preventing differences in brightness from occurring in the display device and improving display quality.

[0033] The effects according to the embodiments are not limited to those exemplified above, and a wider variety of effects are included in this specification. Brief explanation of the drawing

[0034] FIG. 1 is a schematic plan view of a display device according to one embodiment. FIG. 2 is a cross-sectional view schematically showing some subpixels of a display device according to one embodiment. FIG. 3 is a plan view showing one pixel of a display device according to one embodiment. Figure 4 is a cross-sectional view taken along the Q1-Q1' line, Q2-Q2' line and Q3-Q3' line of Figure 3. FIG. 5 is a schematic diagram of a light-emitting element according to one embodiment. FIG. 6 is a schematic plan view of an inkjet printing device according to one embodiment. FIG. 7 is a schematic bottom view of a print head unit according to one embodiment. FIG. 8 is a schematic diagram showing the operation of a print head unit according to one embodiment. FIG. 9 is a schematic diagram showing a print head unit according to one embodiment. FIG. 10 is a cross-sectional view schematically showing an example of an inkjet head according to one embodiment. FIGS. 11 and FIGS. 12 are cross-sectional views schematically illustrating different examples of an inkjet head according to one embodiment. FIG. 13 is a schematic cross-sectional view of an inkjet head according to another embodiment. FIG. 14 is a cross-sectional view schematically showing an inkjet head according to another embodiment. FIG. 15 is a schematic plan view showing an example of the bottom surface of a base part and a rotating member according to another embodiment. FIG. 16 is a schematic plan view showing another example of the bottom surface of a base part and a rotating member according to another embodiment. FIG. 17 is a cross-sectional view schematically showing an inkjet head according to another embodiment. FIG. 18 is a cross-sectional view schematically showing the vibration of the sedimentation prevention member and particles. Figure 19 is a schematic diagram showing the charged state of the particles. FIG. 20 is a cross-sectional view schematically showing an inkjet head according to another embodiment. Specific details for implementing the invention

[0035] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims.

[0036] When elements or layers are referred to as being "on" another element or layer, this includes cases where another layer or element is interposed directly on or in the middle of another element. Throughout the specification, the same reference numerals refer to the same components. Shapes, sizes, ratios, angles, numbers, etc., disclosed in the drawings for describing embodiments are exemplary and therefore the invention is not limited to the depicted details.

[0037] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another. Therefore, it goes without saying that the first component mentioned below may also be the second component within the technical scope of the present invention.

[0038] The features of each of the various embodiments of the present invention may be combined or combined with one another, either partially or wholly, and may technically enable various interlocking and operation. Each embodiment may be implemented independently of one another or may be implemented together in an associated relationship.

[0039] Specific embodiments will be described below with reference to the attached drawings.

[0040] FIG. 1 is a schematic plan view of a display device according to one embodiment.

[0041] Referring to FIG. 1, the display device (10) displays a video or a still image. The display device (10) may refer to any electronic device that provides a display screen. For example, a television, laptop, monitor, billboard, Internet of Things, mobile phone, smartphone, tablet PC (Personal Computer), electronic watch, smart watch, watch phone, head-mounted display, mobile communication terminal, electronic notebook, electronic book, PMP (Portable Multimedia Player), navigation, game console, digital camera, camcorder, etc. that provide a display screen may be included in the display device (10).

[0042] The display device (10) includes a display panel that provides a display screen. Examples of display panels include an inorganic light-emitting diode display panel, an organic light-emitting diode display panel, a quantum dot light-emitting diode display panel, a plasma display panel, a field emission display panel, etc. In the following examples, an inorganic light-emitting diode display panel is used as an example of a display panel, but it is not limited thereto, and if the same technical concept is applicable, it can be applied to other display panels.

[0043] In the drawing describing the display device (10), a first direction (DR1), a second direction (DR2), and a third direction (DR3) are defined. The first direction (DR1) and the second direction (DR2) may be directions perpendicular to each other within a single plane. The third direction (DR3) may be a direction perpendicular to the plane where the first direction (DR1) and the second direction (DR2) are located. The third direction (DR3) is perpendicular to each of the first direction (DR1) and the second direction (DR2). In the embodiment describing the display device (10), the third direction (DR3) represents the thickness direction of the display device (10).

[0044] The shape of the display device (10) can be varied in many ways. For example, the display device (10) may have a rectangular shape in which the first direction (DR1) in the plane includes a longer side than the second direction (DR2). As another example, the display device (10) may have a rectangular shape in which the second direction (DR2) in the plane includes a longer side than the first direction (DR1). However, it is not limited thereto and may have a shape such as a square, a square with rounded corners (vertices), other polygons, a circle, etc. The shape of the display area (DPA) of the display device (10) may also be similar to the overall shape of the display device (10). In FIG. 1, a display device (10) and a display area (DPA) having a rectangular shape in which the first direction (DR1) is longer than the second direction (DR2) are illustrated.

[0045] The display device (10) may include a display area (DPA) and a non-display area (NDA). The display area (DPA) is an area where the screen can be displayed, and the non-display area (NDA) is an area where the screen is not displayed. The display area (DPA) may also be referred to as an active area, and the non-display area (NDA) as an inactive area. The display area (DPA) may generally occupy the center of the display device (10).

[0046] The display area (DPA) may include a plurality of pixels (PX). The plurality of pixels (PX) may be arranged in a matrix direction. The shape of each pixel (PX) may be a planar rectangle or a square, but is not limited thereto, and may be a rhombus shape with each side tilted toward one direction. Each pixel (PX) may be arranged alternately in a stripe type or a pentile type. Additionally, each of the pixels (PX) may include one or more light-emitting elements (30) that emit light of a specific wavelength range to display a specific color.

[0047] A non-display area (NDA) may be placed around a display area (DPA). The non-display area (NDA) may surround the display area (DPA) in whole or in part. The display area (DPA) is rectangular in shape, and the non-display area (NDA) may be placed adjacent to the four sides of the display area (DPA). The non-display area (NDA) may form the bezel of the display device (10). In each non-display area (NDA), wiring or circuit drivers included in the display device (10) may be placed, or external devices may be mounted.

[0048] FIG. 2 is a cross-sectional view schematically showing some subpixels of a display device according to one embodiment.

[0049] Referring to FIG. 2, the display area (DPA) of the display device (10) may include first to third light-emitting areas (LA1, LA2, LA3). Each of the first to third light-emitting areas (LA1, LA2, LA3) may be an area where light generated from a light-emitting element (30) of the display device (10) is emitted to the outside of the display device (10).

[0050] The display device (10) may include a substrate (11), a buffer layer (12), a transistor layer (TFTL), a light-emitting element layer (EML), a wavelength conversion layer (WLCL), a color filter layer (CFL), and an encapsulation layer (TFE).

[0051] The substrate (11) may be a base substrate or a base member and may be made of an insulating material such as a polymer resin. For example, the substrate (11) may be a flexible substrate capable of bending, folding, rolling, etc. The substrate (11) may include polyimide (PI), but is not limited thereto.

[0052] The buffer layer (12) may be disposed on the substrate (11). The buffer layer (12) may be made of an inorganic film capable of preventing the penetration of air or moisture. For example, the buffer layer (12) may include a plurality of inorganic films stacked alternately.

[0053] A transistor layer (TFTL) may be disposed on the buffer layer (12). The transistor layer (TFTL) may include a first transistor (T1), a first gate insulating layer (13), a first interlayer insulating layer (15), a second interlayer insulating layer (17), and a first flattening layer (19).

[0054] The first transistor (T1) may be placed on the buffer layer (BF) and may constitute a pixel circuit for each of a plurality of pixels. For example, the first transistor (T1) may be a driving transistor or a switching transistor of a pixel circuit. The first transistor (T1) may include an active layer (ACT), a gate electrode (G1), a source electrode (SE), and a drain electrode (DE). The active layer (ACT) may include a plurality of conductive regions (ACTa, ACTb) and a channel region (ACTc) between them.

[0055] A light-emitting element layer (EML) may be disposed on a transistor layer (TFTL). The light-emitting element layer (EML) may include a first bank (BNK1), a light-emitting element (30), and a second bank (BNK2). The light-emitting element (30) may be disposed on the first transistor (T1). The light-emitting element (30) may be disposed between the first electrode and the second electrode and connected to the first contact electrode and the second contact electrode, respectively.

[0056] A detailed description of the aforementioned transistor layer (TFTL) and light-emitting element layer (EML) will be provided later with reference to FIGS. 3 to 5.

[0057] A second flattening layer (41) may be disposed on the light-emitting element layer (EML) to flatten the top of the light-emitting element layer (EML). The second flattening layer (41) may include an organic material. For example, the second flattening layer (41) may include at least one of acrylic resin, epoxy resin, phenolic resin, polyamide resin, and polyimide resin.

[0058] The wavelength conversion layer (WLCL) may include a first capping layer (CAP1), a first light-blocking member (BK1), a first wavelength conversion unit (WLC1), a second wavelength conversion unit (WLC2), a light-transmitting unit (LTU), a second capping layer (CAP2), and a third flattening layer (43).

[0059] The first capping layer (CAP1) may be disposed on the second planarization layer (41) of the light-emitting element layer (EML). The first capping layer (CAP1) may seal the lower surface of the first and second wavelength conversion units (WLC1, WLC2) and the light transmission unit (LTU). The first capping layer (CAP1) may include an inorganic material. For example, the first capping layer (CAP1) may include at least one of silicon nitride, aluminum nitride, zirconium nitride, titanium nitride, hafnium nitride, tantalum nitride, silicon oxide, aluminum oxide, titanium oxide, tin oxide, cerium oxide, and silicon oxynitride.

[0060] The first light-blocking member (BK1) may be placed in the first to third light-blocking regions (BA1, BA2, BA3) on the first capping layer (CAP1). The first light-blocking member (BK1) may overlap with the second bank (BNK2) in the thickness direction. The first light-blocking member (BK1) can block the transmission of light. The first light-blocking member (BK1) can improve color reproduction by preventing light from intruding and mixing between the first to third light-emitting regions (LA1, LA2, LA3). The first light-blocking member (BK1) may be arranged in a grid shape surrounding the first to third light-emitting regions (LA1, LA2, LA3) on a plane.

[0061] The first light-blocking member (BK1) may include an organic light-blocking material and a liquid-repellent component. Here, the liquid-repellent component may be composed of a fluorine-containing monomer or a fluorine-containing polymer, and specifically may include a fluorine-containing aliphatic polycarbonate. For example, the first light-blocking member (BK1) may be composed of a black organic material containing the liquid-repellent component. The first light-blocking member (BK1) may be formed through a coating and exposure process, etc., of an organic light-blocking material containing the liquid-repellent component.

[0062] The first light-blocking member (BK1) can separate the first and second wavelength conversion sections (WLC1, WLC2) and the light transmission section (LTU) into corresponding light-emitting regions (LA) by including a liquid-repellent component. For example, if the first and second wavelength conversion sections (WLC1, WLC2) and the light transmission section (LTU) are formed by an inkjet method, an ink composition may flow on the upper surface of the first light-blocking member (BK1). In this case, the first light-blocking member (BK1) can induce the ink composition to flow into each light-emitting region by including a liquid-repellent component. Therefore, the first light-blocking member (BK1) can prevent the ink composition from mixing.

[0063] A first wavelength conversion unit (WLC1) may be disposed in a first light-emitting region (LA1) on a first capping layer (CAP1). The first wavelength conversion unit (WLC1) may be surrounded by a first light-blocking member (BK1). The first wavelength conversion unit (WLC1) may include a first base resin (BS1), a first scatterer (SCT1), and a first wavelength shifter (WLS1).

[0064] The first base resin (BS1) may include a material with a relatively high light transmittance. The first base resin (BS1) may be made of a transparent organic material. For example, the first base resin (BS1) may include at least one of organic materials such as an epoxy resin, an acrylic resin, a cardo resin, and an imide resin.

[0065] The first scatterer (SCT1) may have a refractive index different from that of the first base resin (BS1) and may form an optical interface with the first base resin (BS1). For example, the first scatterer (SCT1) may include a light-scattering material or light-scattering particles that scatter at least a portion of the transmitted light. For example, the first scatterer (SCT1) may include metal oxide particles such as titanium oxide (TiO2), zirconium oxide (ZrO2), aluminum oxide (Al2O3), indium oxide (In2O3), zinc oxide (ZnO), or tin oxide (SnO2), or organic particles such as acrylic resin or urethane resin. The first scatterer (SCT1) may scatter light in a random direction regardless of the incident direction of the incident light without substantially changing the peak wavelength of the incident light.

[0066] The first wavelength shifter (WLS1) can convert or shift the peak wavelength of incident light to the first peak wavelength. For example, the first wavelength shifter (WLS1) can convert and emit blue light provided by the display device (10) into red light having a single peak wavelength in the range of 610 nm to 650 nm. The first wavelength shifter (WLS1) may be a quantum dot, a quantum rod, or a phosphor. A quantum dot may be a particulate material that emits a specific color as electrons transition from the conduction band to the valence band.

[0067] For example, quantum dots can be semiconductor nanocrystalline materials. Depending on their composition and size, quantum dots can have a specific band gap and emit light with a specific wavelength after absorbing light. Examples of semiconductor nanocrystalline quantum dots include group IV nanocrystals, group II-VI compound nanocrystals, group III-V compound nanocrystals, group IV-VI nanocrystals, or combinations thereof.

[0068] For example, a quantum dot may have a core-shell structure comprising a core containing the aforementioned nanocrystal and a shell surrounding the core. The shell of the quantum dot may serve as a protective layer to maintain semiconductor properties by preventing chemical degradation of the core, and as a charging layer to impart electrophoretic properties to the quantum dot. The shell may be a single layer or a multilayer. The interface between the core and the shell may have a concentration gradient in which the concentration of elements present in the shell decreases toward the center. The shell of the quantum dot may be composed of metal or non-metal oxides, semiconductor compounds, or combinations thereof.

[0069] The light emitted by the first wavelength shifter (WLS1) may have a Full Width of Half Maximum (FWHM) of the emission wavelength spectrum of 45 nm or less, 40 nm or less, or 30 nm or less, and the color purity and color reproducibility of the color displayed by the display device (10) can be further improved. The light emitted by the first wavelength shifter (WLS1) may be emitted in multiple directions regardless of the incident direction of the incident light. Accordingly, the side visibility of red displayed in the first emission region (LA1) can be improved.

[0070] A portion of the blue light provided by the light-emitting element layer (EML) may pass through the first wavelength conversion unit (WLC1) without being converted into red light by the first wavelength shifter (WLS1). Among the blue light provided by the light-emitting element layer (EML), the light incident on the first color filter (CF1) without being converted by the first wavelength conversion unit (WLC1) may be blocked by the first color filter (CF1). Furthermore, among the blue light provided by the light-emitting element layer (EML), the red light converted by the first wavelength conversion unit (WLC1) may pass through the first color filter (CF1) and be emitted to the outside. Therefore, the first light-emitting region (LA1) may emit red light.

[0071] The second wavelength converter (WLC2) may be disposed in the second light-emitting region (LA2) on the first capping layer (CAP1). The second wavelength converter (WLC2) may be surrounded by the first light-blocking member (BK1). The second wavelength converter (WLC2) may include a second base resin (BS2), a second scatterer (SCT2), and a second wavelength shifter (WLS2).

[0072] The second base resin (BS2) may include a material with relatively high light transmittance. The second base resin (BS2) may be made of a transparent organic material. For example, the second base resin (BS2) may be made of the same material as the first base resin (BS1) or may be made of the material exemplified in the first base resin (BS1).

[0073] The second scatterer (SCT2) may have a refractive index different from that of the second base resin (BS2) and may form an optical interface with the second base resin (BS2). For example, the second scatterer (SCT2) may include a light-scattering material or light-scattering particles that scatter at least a portion of the transmitted light. For example, the second scatterer (SCT2) may be made of the same material as the first scatterer (SCT1) or may be made of the material exemplified in the first scatterer (SCT1). The second scatterer (SCT2) may scatter light in random directions regardless of the incident direction of the incident light without substantially changing the peak wavelength of the incident light.

[0074] The second wavelength shifter (WLS2) can convert or shift the peak wavelength of incident light to a second peak wavelength different from the first peak wavelength of the first wavelength shifter (WLS1). For example, the second wavelength shifter (WLS2) can convert and emit blue light provided by the display device (10) into green light having a single peak wavelength in the range of 510 nm to 550 nm. The second wavelength shifter (WLS2) may be a quantum dot, a quantum rod, or a phosphor. The second wavelength shifter (WLS2) may include a material of the same nature as the material exemplified in the first wavelength shifter (WLS1). The wavelength conversion range of the second wavelength shifter (WLS2) may be made of a quantum dot, a quantum rod, or a phosphor such that it is different from the wavelength conversion range of the first wavelength shifter (WLS1).

[0075] The light-transmitting unit (LTU) may be disposed in a third light-emitting region (LA3) on the first capping layer (CAP1). The light-transmitting unit (LTU) may be surrounded by a first light-blocking member (BK1). The light-transmitting unit (LTU) may transmit while maintaining the peak wavelength of the incident light. The light-transmitting unit (LTU) may include a third base resin (BS3) and a third scatterer (SCT3).

[0076] The third base resin (BS3) may include a material with relatively high light transmittance. The third base resin (BS3) may be made of a transparent organic material. For example, the third base resin (BS3) may be made of the same material as the first or second base resin (BS1, BS2), or may be made of the material exemplified in the first or second base resin (BS1, BS2).

[0077] The third scatterer (SCT3) may have a refractive index different from that of the third base resin (BS3) and may form an optical interface with the third base resin (BS3). For example, the third scatterer (SCT3) may include a light-scattering material or light-scattering particles that scatter at least a portion of the transmitted light. For example, the third scatterer (SCT3) may be made of the same material as the first or second scatterer (SCT1, SCT2) or may be made of the material exemplified in the first or second scatterer (SCT1, SCT2). The third scatterer (SCT3) may scatter light in random directions regardless of the incident direction of the incident light without substantially changing the peak wavelength of the incident light.

[0078] Since the wavelength conversion layer (WLCL) is placed directly on the second planarization layer (41) of the light-emitting element layer (EML), the display device (10) may not require a separate substrate for the first and second wavelength conversion sections (WLC1, WLC2) and the light transmission section (LTU). Accordingly, the first and second wavelength conversion sections (WLC1, WLC2) and the light transmission section (LTU) can be easily aligned with each of the first to third light-emitting regions (LA1, LA2, LA3), and the thickness of the display device (10) can be relatively reduced.

[0079] The second capping layer (CAP2) may cover the first and second wavelength conversion sections (WLC1, WLC2), the light transmission section (LTU), and the first light-blocking member (BK1). For example, the second capping layer (CAP2) may seal the first and second wavelength conversion sections (WLC1, WLC2) and the light transmission section (LTU) to prevent damage or contamination of the first and second wavelength conversion sections (WLC1, WLC2) and the light transmission section (LTU). The second capping layer (CAP2) may be made of the same material as the first capping layer (CAP1) or may be made of the material exemplified in the first capping layer (CAP1).

[0080] The third flattening layer (43) is disposed on top of the second capping layer (CAP2) to flatten the top of the first and second wavelength conversion sections (WLC1, WLC2) and the light transmission section (LTU). The third flattening layer (43) may include an organic material. For example, the third flattening layer (43) may include at least one of acrylic resin, epoxy resin, phenolic resin, polyamide resin, and polyimide resin.

[0081] The color filter layer (CFL) may include a second light-blocking member (BK2), first to third color filters (CF1, CF2, CF3), and a protective layer (PRT).

[0082] The second light-blocking member (BK2) may be placed on the third flattening layer (43) of the wavelength conversion layer (WLCL) in the first to third light-blocking regions (BA1, BA2, BA3). The second light-blocking member (BK2) may overlap with the first light-blocking member (BK1) or the second bank (BNK2) in the thickness direction. The second light-blocking member (BK2) can block the transmission of light. The second light-blocking member (BK2) can improve the color reproduction rate by preventing light from interfering and mixing between the first to third light-emitting regions (LA1, LA2, LA3). The second light-blocking member (BK2) may be arranged in a grid shape surrounding the first to third light-emitting regions (LA1, LA2, LA3) on a plane.

[0083] A first color filter (CF1) may be placed in a first light-emitting region (LA1) on a third planarization layer (OC3). The first color filter (CF1) may be surrounded by a second light-blocking member (BK2). The first color filter (CF1) may overlap with the first wavelength conversion unit (WLC1) in the thickness direction. The first color filter (CF1) may selectively transmit light of a first color (e.g., red light) and block or absorb light of a second color (e.g., green light) and light of a third color (e.g., blue light). For example, the first color filter (CF1) may be a red color filter and may include a red colorant. The red colorant may consist of a red dye or a red pigment.

[0084] The second color filter (CF2) may be placed in the second light-emitting region (LA2) on the third flattening layer (43). The second color filter (CF2) may be surrounded by a second light-blocking member (BK2). The second color filter (CF2) may overlap with the second wavelength conversion unit (WLC2) in the thickness direction. The second color filter (CF2) may selectively transmit light of the second color (e.g., green light) and block or absorb light of the first color (e.g., red light) and light of the third color (e.g., blue light). For example, the second color filter (CF2) may be a green color filter and may include a green colorant. The green colorant may consist of a green dye or a green pigment.

[0085] A third color filter (CF3) may be placed in a third light-emitting region (LA3) on the third flattening layer (43). The third color filter (CF3) may be surrounded by a second light-blocking member (BK2). The third color filter (CF3) may overlap with the light-transmitting portion (LTU) in the thickness direction. The third color filter (CF3) may selectively transmit light of a third color (e.g., blue light) and block or absorb light of a first color (e.g., red light) and light of a second color (e.g., green light). For example, the third color filter (CF3) may be a blue color filter and may include a blue colorant. The blue colorant may consist of a blue dye or a blue pigment.

[0086] The first to third color filters (CF1, CF2, CF3) can absorb a portion of the light entering from outside the display device (10) to reduce reflected light caused by external light. Accordingly, the first to third color filters (CF1, CF2, CF3) can prevent color distortion caused by external light reflection.

[0087] Since the first to third color filters (CF1, CF2, CF3) are placed directly on the third planarization layer (43) of the wavelength conversion layer (WLCL), the display device (10) may not require a separate substrate for the first to third color filters (CF1, CF2, CF3). Accordingly, the thickness of the display device (10) may be relatively reduced.

[0088] The third protective layer (PRT) can cover the first to third color filters (CF1, CF2, CF3). The third protective layer (PRT) can protect the first to third color filters (CF1, CF2, CF3).

[0089] The encapsulation layer (TFE) may be placed on the third protective layer (PRT) of the color filter layer (CFL). The encapsulation layer (TFE) may cover the upper surface and sides of the display layer. For example, the encapsulation layer (TFE) may include at least one inorganic film to prevent oxygen or moisture from penetrating. Additionally, the encapsulation layer (TFE) may include at least one organic film to protect the display device (10) from foreign substances such as dust.

[0090] Hereinafter, the transistor layer (TFTL) and the light-emitting element layer (EML) will be described in detail through the planar and cross-sectional structures of a pixel of a display device according to one embodiment.

[0091] FIG. 3 is a plan view showing one pixel of a display device according to one embodiment.

[0092] Referring to FIG. 3, each of the plurality of pixels (PX) may include a plurality of subpixels (PXn, where n is an integer from 1 to 3). For example, one pixel (PX) may include a first subpixel (PX1), a second subpixel (PX2), and a third subpixel (PX3). The first subpixel (PX1) may emit light of a first color, the second subpixel (PX2) may emit light of a second color, and the third subpixel (PX3) may emit light of a third color. As an example, the first color may be blue, the second color may be green, and the third color may be red. However, not limited thereto, each subpixel (PXn) may emit light of the same color. Also, while FIG. 2 illustrates a pixel (PX) including three subpixels (PXn), not limited thereto, the pixel (PX) may include a larger number of subpixels (PXn).

[0093] Each subpixel (PXn) of the display device (10) may include a light-emitting region (EMA) and a non-light-emitting region (not shown). The light-emitting region (EMA) is a region where a light-emitting element (30) is placed and light of a specific wavelength range is emitted, and the non-light-emitting region may be a region where a light-emitting element (30) is not placed and light emitted from the light-emitting element (30) does not reach, so no light is emitted. The light-emitting region may include a region where a light-emitting element (30) is placed, and may include a region adjacent to the light-emitting element (30) where light emitted from the light-emitting element (30) is emitted.

[0094] Not limited thereto, the light-emitting region may also include a region where light emitted from a light-emitting element (30) is reflected or refracted by another member and emitted. A plurality of light-emitting elements (30) are arranged in each sub-pixel (PXn), and a light-emitting region may be formed by including the region where they are arranged and the region adjacent thereto.

[0095] Additionally, each subpixel (PXn) may include a cutting area (CBA) placed in a non-emissive region. The cutting area (CBA) may be placed on one side of the second direction (DR2) of the emitting region (EMA). The cutting area (CBA) may be placed between the emitting regions (EMA) of the subpixels (PXn) adjacent in the second direction (DR2). A plurality of emitting regions (EMA) and cutting areas (CBA) may be arranged in the display area (DPA) of the display device (10). For example, a plurality of emitting regions (EMA) and cutting areas (CBA) may be arranged repeatedly in the first direction (DR1), while the emitting regions (EMA) and cutting areas (CBA) may be arranged alternately in the second direction (DR2). Additionally, the spacing of the cutting areas (CBA) in the first direction (DR1) may be smaller than the spacing of the emitting regions (EMA) in the first direction (DR1). A second bank (BNL2) is disposed between the cutting regions (CBA) and the light-emitting regions (EMA), and the spacing between them may vary depending on the width of the second bank (BNL2). Light is not emitted because the light-emitting element (30) is not disposed in the cutting region (CBA), but some of the electrodes (21, 22) disposed in each subpixel (PXn) may be disposed therein. The electrodes (21, 22) disposed in each subpixel (PXn) may be disposed separated from each other in the cutting region (CBA).

[0096] FIG. 4 is a cross-sectional view taken along the Q1-Q1' line, Q2-Q2' line and Q3-Q3' line of FIG. 3. FIG. 4 illustrates a cross-section across both ends of a light-emitting element (30) placed in the first subpixel (PX1) of FIG. 3.

[0097] Referring to FIG. 4 in conjunction with FIG. 3, the display device (10) may include a substrate (11) and a semiconductor layer, a plurality of conductive layers, and a plurality of insulating layers disposed on the substrate (11). The semiconductor layer, the conductive layer, and the insulating layers may each constitute a circuit layer and a light-emitting element layer of the display device (10).

[0098] A light-blocking layer (BML) may be disposed on a substrate (11). The light-blocking layer (BML) may be disposed to overlap with the active layer (ACT) of the first transistor (T1) of the display device (10). The light-blocking layer (BML) may include a material that blocks light, thereby preventing light from being incident on the active layer (ACT) of the first transistor (T1). For example, the light-blocking layer (BML) may be formed of an opaque metallic material that blocks the transmission of light. However, it is not limited thereto, and in some cases, the light-blocking layer (BML) may be omitted.

[0099] The buffer layer (12) may be disposed over the entire surface of the substrate (11), including a light-blocking layer (BML). The buffer layer (12) is formed on the substrate (11) to protect the first transistors (T1) of the pixel (PX) from moisture penetrating through the substrate (11), which is susceptible to moisture permeability, and can perform a surface flattening function. The buffer layer (12) may be composed of a plurality of inorganic layers that are alternately stacked. For example, the buffer layer (12) may be formed as a multilayer in which inorganic layers comprising at least one of silicon oxide (SiOx), silicon nitride (SiNx), and silicon oxynitride (SiOxNy) are alternately stacked.

[0100] The semiconductor layer may be placed on the buffer layer (12). The semiconductor layer may include the active layer (ACT) of the first transistor (T1). These may be arranged to partially overlap with the gate electrode (G1) of the first gate conductive layer described later.

[0101] Meanwhile, the drawing shows only the first transistor (T1) among the transistors included in the subpixel (PXn) of the display device (10), but is not limited thereto. The display device (10) may include a larger number of transistors. For example, the display device (10) may include two or three transistors by including one or more additional transistors in addition to the first transistor (T1) for each subpixel (PXn).

[0102] The semiconductor layer may include polycrystalline silicon, single-crystal silicon, oxide semiconductors, etc. When the semiconductor layer includes an oxide semiconductor, each active layer (ACT) may include a plurality of conductive regions (ACTa, ACTb) and channel regions (ACTc) between them. The oxide semiconductor may be an oxide semiconductor containing indium (In). For example, the oxide semiconductor may be indium-tin oxide (ITO), indium-zinc oxide (IZO), indium-gallium oxide (IGO), indium-zinc-tin oxide (IZTO), indium-gallium-tin oxide (IGTO), indium-gallium-zinc oxide (IGZO), indium-gallium-zinc-tin oxide (IGZTO), etc.

[0103] In another embodiment, the semiconductor layer may include polycrystalline silicon. Polycrystalline silicon can be formed by crystallizing amorphous silicon, in which case the conductive regions of the active layer (ACT) may each be doped regions doped with impurities.

[0104] The first gate insulating layer (13) may be disposed on the semiconductor layer and the buffer layer (12). The first gate insulating layer (13) may be disposed on the buffer layer (12) including the semiconductor layer. The first gate insulating layer (13) may function as a gate insulating film for each transistor. The first gate insulating layer (13) may be composed of an inorganic layer including an inorganic material, such as silicon oxide (SiOx), silicon nitride (SiNx), or silicon oxynitride (SiOxNy), or may be formed in a stacked structure.

[0105] A first gate conductive layer may be disposed on a first gate insulating layer (13). The first gate conductive layer may include a gate electrode (G1) of a first transistor (T1) and a first capacitive electrode (CSE1) of a storage capacitor. The gate electrode (G1) may be disposed to overlap in the thickness direction with the channel region (ACTc) of the active layer (ACT). The first capacitive electrode (CSE1) may be disposed to overlap in the thickness direction with a second capacitive electrode (CSE2) described later. In one embodiment, the first capacitive electrode (CSE1) may be connected to the gate electrode (G1) and integrated. The first capacitive electrode (CSE1) may be disposed to overlap in the thickness direction with the second capacitive electrode (CSE2), and a storage capacitor may be formed between them.

[0106] The first gate conductive layer may be formed as a single layer or a multilayer composed of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof. However, it is not limited thereto.

[0107] The first interlayer insulating layer (15) may be disposed on the first gate conductive layer. The first interlayer insulating layer (15) may function as an insulating film between the first gate conductive layer and other layers disposed thereon. Additionally, the first interlayer insulating layer (15) may be disposed to cover the first gate conductive layer and perform a protective function thereon. The first interlayer insulating layer (15) may be composed of an inorganic layer including an inorganic material, such as silicon oxide (SiOx), silicon nitride (SiNx), or silicon oxynitride (SiOxNy), or may be formed in a stacked structure.

[0108] The first data conductive layer may be disposed on the first interlayer insulating layer (15). The first data conductive layer may include a first source electrode (SE) and a first drain electrode (DE), a data line (DTL), and a second capacitance electrode (CSE2) of the first transistor (T1).

[0109] The first source electrode (SE) and the first drain electrode (DE) of the first transistor (T1) can each come into contact with the doping regions (ACTa, ACTb) of the active layer (ACT) through a contact hole penetrating the first interlayer insulating layer (15) and the first gate insulating layer (13). Additionally, the first source electrode (SE) of the first transistor (T1) can be electrically connected to the light-blocking layer (BML) through another contact hole.

[0110] The data line (DTL) can apply a data signal to another transistor (not shown) included in the display device (10). Although not shown in the drawing, the data line (DTL) can be connected to the source / drain electrodes of another transistor to transmit the signal applied from the data line (DTL).

[0111] The second capacitance electrode (CSE2) may be arranged to overlap the first capacitance electrode (CSE1) in the thickness direction. In one embodiment, the second capacitance electrode (CSE2) may be integrated and connected with the first source electrode (SE).

[0112] The first data conductive layer may be formed as a single layer or a multilayer composed of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof. However, it is not limited thereto.

[0113] The second interlayer insulating layer (17) may be disposed on the first data conductive layer. The second interlayer insulating layer (17) may function as an insulating film between the first data conductive layer and other layers disposed thereon. Additionally, the second interlayer insulating layer (17) may cover the first data conductive layer and perform the function of protecting the first data conductive layer. The second interlayer insulating layer (17) may be composed of an inorganic layer including inorganic materials, such as silicon oxide (SiOx), silicon nitride (SiNx), and silicon oxynitride (SiOxNy), or may be formed in a stacked structure.

[0114] The second data conductive layer may be disposed on the second interlayer insulating layer (17). The second data conductive layer may include a first voltage line (VL1), a second voltage line (VL2), and a first conductive pattern (CDP). A high potential voltage (or a first power supply voltage) supplied to the first transistor (T1) may be applied to the first voltage line (VL1), and a low potential voltage (or a second power supply voltage) supplied to the second electrode (22) may be applied to the second voltage line (VL2). Additionally, an alignment signal required to align the light-emitting element (30) during the manufacturing process of the display device (10) may be applied to the second voltage line (VL2).

[0115] The first conductive pattern (CDP) can be connected to the second capacitance electrode (CSE2) through a contact hole formed in the second interlayer insulating layer (17). The second capacitance electrode (CSE2) can be integrated with the first source electrode (SE) of the first transistor (T1), and the first conductive pattern (CDP) can be electrically connected to the first source electrode (SE). The first conductive pattern (CDP) also contacts the first electrode (21) described later, and the first transistor (T1) can transmit the first power supply voltage applied from the first voltage wiring (VL1) to the first electrode (21) through the first conductive pattern (CDP). Meanwhile, although the drawing shows the second data conductive layer including one second voltage wiring (VL2) and one first voltage wiring (VL1), it is not limited thereto. The second data conductive layer may include a larger number of first voltage wirings (VL1) and second voltage wirings (VL2).

[0116] The second data conductive layer may be formed as a single layer or a multilayer composed of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof. However, it is not limited thereto.

[0117] The first planarization layer (19) may be disposed on the second data conductive layer. The first planarization layer (19) may include an organic insulating material, such as polyimide (PI), and may perform a surface planarization function.

[0118] A plurality of first banks (BNL1), a plurality of electrodes (21, 22), a light-emitting element (30), a plurality of contact electrodes (CNE1, CNE2) and a second bank (BNL2) may be disposed on the first flattening layer (19). Additionally, a plurality of insulating layers (PAS1, PAS2, PAS3, PAS4) may be disposed on the first flattening layer (19).

[0119] A plurality of first banks (BNL1) may be placed directly on the first planarization layer (19). A plurality of first banks (BNL1) may have a shape that extends in a second direction (DR2) within each subpixel (PXn), but may not extend to other adjacent subpixels (PXn) in the second direction (DR2) and may be placed within the light-emitting region (EMA). Additionally, a plurality of first banks (BNL1) may be spaced apart from each other in the first direction (DR1), and a light-emitting element (30) may be placed between them. A plurality of first banks (BNL1) may be placed for each subpixel (PXn) to form a linear pattern in the display area (DPA) of the display device (10). Although two first banks (BNL1) are shown in the drawing, they are not limited thereto. A larger number of first banks (BNL1) may be placed depending on the number of electrodes (21, 22).

[0120] The first bank (BNL1) may have a structure in which at least a portion protrudes with respect to the upper surface of the first flattening layer (19). The protruding portion of the first bank (BNL1) may have an inclined side, and light emitted from the light-emitting element (30) may be reflected from the electrodes (21, 22) placed on the first bank (BNL1) and emitted in the upward direction of the first flattening layer (19). The first bank (BNL1) may provide an area where the light-emitting element (30) is placed and may also perform the function of a reflective barrier that reflects light emitted from the light-emitting element (30) in an upward direction. The side of the first bank (BNL1) may be inclined in a linear shape, but is not limited thereto, and the first bank (BNL1) may have a shape of a semicircle or semi-ellipse with a curved outer surface. The first banks (BNL1) may include an organic insulating material such as polyimide (PI), but are not limited thereto.

[0121] A plurality of electrodes (21, 22) may be disposed on the first bank (BNL1) and the first flattening layer (19). The plurality of electrodes (21, 22) may include a first electrode (21) and a second electrode (22). The first electrode (21) and the second electrode (22) extend in a second direction (DR2), and may be disposed so as to be spaced apart from each other in a first direction (DR1).

[0122] The first electrode (21) and the second electrode (22) may each extend in a second direction (DR2) within a subpixel (PXn) and be separated from other electrodes (21, 22) in a cutting region (CBA). For example, a cutting region (CBA) may be placed between light-emitting regions (EMA) of subpixels (PXn) adjacent in the second direction (DR2), and the first electrode (21) and the second electrode (22) may be separated from other first electrodes (21) and second electrodes (22) placed in subpixels (PXn) adjacent in the second direction (DR2) in the cutting region (CBA). However, this is not limited thereto, and some electrodes (21, 22) may be placed extending beyond subpixels (PXn) adjacent in the second direction (DR2) without being separated for each subpixel (PXn), or only one of the first electrode (21) or the second electrode (22) may be separated.

[0123] The first electrode (21) may be electrically connected to the first transistor (T1) through the first contact hole (CT1), and the second electrode (22) may be electrically connected to the second voltage wiring (VL2) through the second contact hole (CT2). For example, the first electrode (21) may contact the first conductive pattern (CDP) through the first contact hole (CT1) penetrating the first flattening layer (19) in the portion extended in the first direction (DR1) of the second bank (BNL2). The second electrode (22) may also contact the second voltage wiring (VL2) through the second contact hole (CT2) penetrating the first flattening layer (19) in the portion extended in the first direction (DR1) of the second bank (BNL2). However, it is not limited thereto. In another embodiment, the first contact hole (CT1) and the second contact hole (CT2) may be placed within the light-emitting region (EMA) surrounded by the second bank (BNL2) so as not to overlap with the second bank (BNL2).

[0124] In the drawing, it is illustrated that one first electrode (21) and one second electrode (22) are arranged for each subpixel (PXn), but this is not limited thereto, and the number of first electrodes (21) and second electrodes (22) arranged for each subpixel (PXn) may be greater. Additionally, the first electrode (21) and the second electrode (22) arranged for each subpixel (PXn) may not necessarily have a shape that extends in one direction, and the first electrode (21) and the second electrode (22) may be arranged in various structures. For example, the first electrode (21) and the second electrode (22) may have a partially curved or bent shape, and one electrode may be arranged to surround the other electrode.

[0125] The first electrode (21) and the second electrode (22) may each be placed directly on the first bank (BNL1). The first electrode (21) and the second electrode (22) may each be formed to have a width greater than that of the first bank (BNL1). For example, the first electrode (21) and the second electrode (22) may each be placed to cover the outer surface of the first bank (BNL1). The first electrode (21) and the second electrode (22) are each placed on the side of the first bank (BNL1), and the gap between the first electrode (21) and the second electrode (22) may be narrower than the gap between the first bank (BNL1). Additionally, at least a portion of the first electrode (21) and the second electrode (22) may be placed directly on the first flattening layer (19) so that they are placed on the same plane. However, they are not limited thereto. In some cases, the width of each electrode (21, 22) may be smaller than that of the first bank (BNL1). However, each electrode (21, 22) is positioned to cover at least one side of the first bank (BNL1) so as to reflect light emitted from the light-emitting element (30).

[0126] Each electrode (21, 22) may include a highly reflective conductive material. For example, each electrode (21, 22) may include a metal such as silver (Ag), copper (Cu), or aluminum (Al) as a highly reflective material, or an alloy including aluminum (Al), nickel (Ni), or lanthanum (La). Each electrode (21, 22) may reflect light emitted from the light-emitting element (30) and traveling toward the side of the first bank (BNL1) toward the upper direction of each subpixel (PXn).

[0127] However, not limited thereto, each electrode (21, 22) may further include a transparent conductive material. For example, each electrode (21, 22) may include a material such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), ITZO (Indium Tin-Zinc Oxide), etc. In some embodiments, each electrode (21, 22) may have a structure in which a transparent conductive material and a highly reflective metal layer are each stacked one or more times, or may be formed as a single layer including these. For example, each electrode (21, 22) may have a stacked structure such as ITO / Silver(Ag) / ITO / , ITO / Ag / IZO, or ITO / Ag / ITZO / IZO.

[0128] A plurality of electrodes (21, 22) are electrically connected to light-emitting elements (30), and a predetermined voltage may be applied so that the light-emitting elements (30) emit light. A plurality of electrodes (21, 22) are electrically connected to the light-emitting elements (30) through contact electrodes (CNE1, CNE2), and an electrical signal applied to the electrodes (21, 22) can be transmitted to the light-emitting elements (30) through the contact electrodes (CNE1, CNE2).

[0129] Either one of the first electrode (21) and the second electrode (22) may be electrically connected to the anode electrode of the light-emitting element (30), and the other may be electrically connected to the cathode electrode of the light-emitting element (30). However, this is not limited thereto, and the opposite case may also occur.

[0130] Additionally, each electrode (21, 22) may be utilized to form an electric field within a subpixel (PXn) to align the light-emitting element (30). The light-emitting element (30) may be positioned between the first electrode (21) and the second electrode (22) by means of an electric field formed on the first electrode (21) and the second electrode (22). The light-emitting element (30) of the display device (10) may be sprayed onto the electrodes (21, 22) through an inkjet printing process. When ink containing the light-emitting element (30) is sprayed onto the electrodes (21, 22), an alignment signal is applied to the electrodes (21, 22) to generate an electric field. The light-emitting element (30) dispersed in the ink may be aligned on the electrodes (21, 22) by receiving a dielectrophoretic force from the electric field generated on the electrodes (21, 22).

[0131] A first insulating layer (PAS1) may be disposed on the first flattening layer (19). The first insulating layer (PAS1) may be disposed to cover the first banks (BNL1) and the first electrode (21) and the second electrode (22). The first insulating layer (PAS1) may protect the first electrode (21) and the second electrode (22) while simultaneously insulating them from one another. Additionally, it may prevent the light-emitting element (30) disposed on the first insulating layer (PAS1) from being damaged by direct contact with other members.

[0132] In one embodiment, the first insulating layer (PAS1) may include an opening (OP) that partially exposes the first electrode (21) and the second electrode (22). Each opening (OP) may partially expose a portion of each electrode (21, 22) disposed on the upper surface of the first bank (BNL1). Some of the contact electrodes (CNE1, CNE2) may come into contact with each electrode (21, 22) exposed through the opening (OP).

[0133] The first insulating layer (PAS1) may have a step formed such that a portion of its upper surface is sunken between the first electrode (21) and the second electrode (22). For example, as the first insulating layer (PAS1) is positioned to cover the first electrode (21) and the second electrode (22), its upper surface may be stepped according to the shape of the electrodes (21, 22) positioned below it. However, it is not limited thereto.

[0134] The second bank (BNL2) may be placed on the first insulating layer (PAS1). The second bank (BNL2) may be arranged in a grid pattern across the entire front of the display area (DPA), including portions extending in the first direction (DR1) and the second direction (DR2) in the plane. The second bank (BNL2) may be placed across the boundaries of each subpixel (PXn) to distinguish neighboring subpixels (PXn).

[0135] Additionally, the second bank (BNL2) is positioned to surround the light-emitting region (EMA) and the cut-off region (CBA) placed for each subpixel (PXn), thereby distinguishing them. The first electrode (21) and the second electrode (22) can be extended in the second direction (DR2) and positioned across the portion of the second bank (BNL2) that extends in the first direction (DR1). The portion of the second bank (BNL2) that extends in the second direction (DR2) may have a greater width than the portion positioned between the light-emitting regions (EMA) and the portion positioned between the cut-off regions (CBA). Accordingly, the spacing between the cut-off regions (CBA) may be smaller than the spacing between the light-emitting regions (EMA).

[0136] The second bank (BNL2) may be formed to have a greater height than the first bank (BNL1). The second bank (BNL2) can prevent ink from overflowing into adjacent subpixels (PXn) during the inkjet printing process of the manufacturing process of the display device (10), thereby separating the inks so that the inks in which different light-emitting elements (30) are dispersed in each subpixel (PXn) do not mix with each other. The second bank (BNL2) may include polyimide (PI) as in the first bank (BNL1), but is not limited thereto.

[0137] A light-emitting element (30) may be disposed on a first insulating layer (PAS1). A plurality of light-emitting elements (30) may be spaced apart from each other along a second direction (DR2) in which each electrode (21, 22) is extended and may be aligned substantially parallel to each other. The light-emitting element (30) may have a shape that extends in one direction, and the direction in which each electrode (21, 22) is extended and the direction in which the light-emitting element (30) is extended may be substantially perpendicular. However, this is not limited thereto, and the light-emitting element (30) may be disposed obliquely rather than perpendicular to the direction in which each electrode (21, 22) is extended.

[0138] The light-emitting elements (30) placed in each subpixel (PXn) may include a light-emitting layer ('36' in FIG. 5) containing different materials and emit light of different wavelengths to the outside. Accordingly, light of the first color, the second color, and the third color may be emitted from the first subpixel (PX1), the second subpixel (PX2), and the third subpixel (PX3), respectively. However, this is not limited thereto, and each subpixel (PXn) may include the same type of light-emitting element (30) and emit light of substantially the same color.

[0139] The light-emitting element (30) may have both ends placed on each electrode (21, 22) between the first banks (BNL1). The extended length of the light-emitting element (30) is longer than the distance between the first electrode (21) and the second electrode (22), and both ends of the light-emitting element (30) may be placed on the first electrode (21) and the second electrode (22), respectively. For example, the light-emitting element (30) may be placed such that one end is placed on the first electrode (21) and the other end is placed on the second electrode (22).

[0140] A plurality of layers of the light-emitting element (30) may be arranged in a direction perpendicular to the upper surface of the substrate (11) or the first flattening layer (19). The light-emitting element (30) may be arranged such that one extended direction is parallel to the upper surface of the first flattening layer (19), and a plurality of semiconductor layers included in the light-emitting element (30) may be arranged sequentially along a direction parallel to the upper surface of the first flattening layer (19). However, this is not limited thereto, and if the light-emitting element (30) has a different structure, a plurality of semiconductor layers may be arranged in a direction perpendicular to the upper surface of the first flattening layer (19).

[0141] Both ends of the light-emitting element (30) may each come into contact with contact electrodes (CNE1, CNE2). For example, the light-emitting element (30) may not have an insulating film ('38' in FIG. 5) formed on the extended one-way end surface, and a portion of the semiconductor layer ('31', '32' in FIG. 5) or electrode layer ('37' in FIG. 5) may be exposed, and the exposed semiconductor layer ('31', '32' in FIG. 5) or electrode layer ('37' in FIG. 5) may come into contact with the contact electrodes (CNE1, CNE2). However, not limited thereto, the light-emitting element (30) may have at least a portion of the insulating film (38) removed so that the sides of both ends of the semiconductor layer ('31', '32' in FIG. 5) are partially exposed. The side of the exposed semiconductor layer ('31', '32' in FIG. 5) may also come into direct contact with the contact electrodes (CNE1, CNE2).

[0142] The second insulating layer (PAS2) may be partially disposed on the light-emitting element (30). For example, the second insulating layer (PAS2) may be disposed on the light-emitting element (30) with a width smaller than the length of the light-emitting element (30) so as to surround the light-emitting element (30) and expose both ends of the light-emitting element (30). The second insulating layer (PAS2) may be disposed to cover the light-emitting element (30), electrodes (21, 22), and the first insulating layer (PAS1) during the manufacturing process of the display device (10), and then removed to expose both ends of the light-emitting element (30). The second insulating layer (PAS2) may be disposed extending in a second direction (DR2) on the first insulating layer (PAS1) in a planar manner to form a linear or island pattern within each subpixel (PXn). The second insulating layer (PAS2) can protect the light-emitting element (30) and at the same time fix the light-emitting element (30) during the manufacturing process of the display device (10).

[0143] A plurality of contact electrodes (CNE1, CNE2) and a third insulating layer (PAS3) may be disposed on the second insulating layer (PAS2).

[0144] A plurality of contact electrodes (CNE1, CNE2) may have a shape extending in one direction and may be disposed on each electrode (21, 22). The contact electrodes (CNE1, CNE2) may include a first contact electrode (CNE1) disposed on the first electrode (21) and a second contact electrode (CNE2) disposed on the second electrode (22). Each contact electrode (CNE1, CNE2) may be disposed spaced apart from or facing each other. For example, the first contact electrode (CNE1) and the second contact electrode (CNE2) may be disposed on the first electrode (21) and the second electrode (22), respectively, and spaced apart from each other in a first direction (DR1). Each contact electrode (CNE1, CNE2) may form a stripe pattern within the light-emitting region (EMA) of each subpixel (PXn).

[0145] A plurality of contact electrodes (CNE1, CNE2) can each contact a light-emitting element (30). The first contact electrode (CNE1) can contact one end of the light-emitting element (30), and the second contact electrode (CNE2) can contact the other end of the light-emitting element (30). A semiconductor layer is exposed on both end surfaces of the light-emitting element (30) in an extended direction, and each contact electrode (CNE1, CNE2) can be electrically connected to the semiconductor layer of the light-emitting element (30) by contacting it. One side of the contact electrodes (CNE1, CNE2) that contacts both ends of the light-emitting element (30) can be disposed on the second insulating layer (PAS2). Additionally, the first contact electrode (CNE1) may contact the first electrode (21) through an opening (OP) that exposes a portion of the upper surface of the first electrode (21), and the second contact electrode (CNE2) may contact the second electrode (22) through an opening (OP) that exposes a portion of the upper surface of the second electrode (22).

[0146] Each contact electrode (CNE1, CNE2) may have a width measured in one direction that is smaller than the width measured in one direction of each electrode (21, 22). The contact electrodes (CNE1, CNE2) may be arranged to contact one end and the other end of the light-emitting element (30) and simultaneously cover a portion of the upper surface of the first electrode (21) and the second electrode (22). However, not limited thereto, the contact electrodes (CNE1, CNE2) may be formed with a width larger than that of the electrodes (21, 22) to cover both sides of the electrodes (21, 22).

[0147] The contact electrodes (CNE1, CNE2) may include a transparent conductive material. For example, they may include ITO, IZO, ITZO, aluminum (Al), etc. Light emitted from the light-emitting element (30) may pass through the contact electrodes (CNE1, CNE2) and proceed toward the electrodes (21, 22). However, it is not limited thereto.

[0148] In the drawing, two contact electrodes (CNE1, CNE2) are shown arranged in one subpixel (PXn), but are not limited thereto. The number of each contact electrode (CNE1, CNE2) may vary depending on the number of electrodes (21, 22) arranged in each subpixel (PXn).

[0149] The third insulating layer (PAS3) may be positioned to cover the first contact electrode (CNE1). The third insulating layer (PAS3) may be positioned to cover one side on which the first contact electrode (CNE1) is positioned relative to the second insulating layer (PAS2), including the first contact electrode (CNE1). For example, the third insulating layer (PAS3) may be positioned to cover the first insulating layers (PAS1) positioned on the first contact electrode (CNE1) and the first electrode (21). This positioning may be formed by a process in which the insulating material layer constituting the third insulating layer (PAS3) is positioned in the entire light-emitting region (EMA), and then a portion of the insulating material layer is removed to form the second contact electrode (CNE2). In the above process, the insulating material layer forming the third insulating layer (PAS3) can be removed together with the insulating material layer forming the second insulating layer (PAS2), and one side of the third insulating layer (PAS3) can be aligned with one side of the second insulating layer (PAS2). One side of the second contact electrode (CNE2) is placed on the third insulating layer (PAS3), and can be mutually insulated from the first contact electrode (CNE1) with this in between.

[0150] The fourth insulating layer (PAS4) may be placed over the entire display area (DPA) of the substrate (11). The fourth insulating layer (PAS4) may function to protect the external environment of the components placed on the substrate (11). However, the fourth insulating layer (PAS4) may be omitted.

[0151] Each of the above-described first insulating layer (PAS1), second insulating layer (PAS2), third insulating layer (PAS3), and fourth insulating layer (PAS4) may include an inorganic insulating material or an organic insulating material. For example, the first insulating layer (PAS1), second insulating layer (PAS2), third insulating layer (PAS3), and fourth insulating layer (PAS4) may include inorganic insulating materials such as silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiOxNy), aluminum oxide (Al2O3), aluminum nitride (AlN), etc. Alternatively, these may include, as organic insulating materials, acrylic resin, epoxy resin, phenolic resin, polyamide resin, polyimide resin, unsaturated polyester resin, polyphenylene resin, polyphenylene sulfide resin, benzocyclobutene, cardo resin, siloxane resin, silsesquioxane resin, polymethyl methacrylate, polycarbonate, polymethyl methacrylate-polycarbonate synthetic resin, etc. However, they are not limited thereto.

[0152] FIG. 5 is a schematic diagram of a light-emitting element according to one embodiment.

[0153] Referring to FIG. 5, the light-emitting element (30) is a particle-shaped element and may be a rod or cylindrical shape having a predetermined aspect ratio. The light-emitting element (30) may have a size ranging from a nanometer scale (1 nm or more and less than 1 µm) to a micrometer scale (1 µm or more and less than 1 mm). In one embodiment, the light-emitting element (30) may have both a diameter and a length of a nanometer scale or both of micrometer scales. In some other embodiments, the diameter of the light-emitting element (30) may have a nanometer scale, while the length of the light-emitting element (30) may have a micrometer scale. In some embodiments, some of the light-emitting elements (30) may have a diameter and / or length of a nanometer scale, while other parts of the light-emitting elements (30) may have a diameter and / or length of a micrometer scale.

[0154] In one embodiment, the light-emitting element (30) may be an inorganic light-emitting diode. Specifically, the light-emitting element (30) may include a semiconductor layer doped with any conductivity type (e.g., p-type or n-type) impurity. The semiconductor layer receives an electrical signal applied from an external power source and can emit it as light of a specific wavelength range.

[0155] A light-emitting element (30) according to one embodiment may include a first semiconductor layer (31), an active layer (33), a second semiconductor layer (32), and an electrode layer (37) that are sequentially stacked in the longitudinal direction. The light-emitting element may further include an insulating film (38) covering the outer surface of the first semiconductor layer (31), the second semiconductor layer (32), and the active layer (33).

[0156] The first semiconductor layer (31) may be an n-type semiconductor. When the light-emitting element (30) emits light in the blue wavelength range, the first semiconductor layer (31) may include a semiconductor material having the chemical formula AlxGayIn1-x-yN (0≤x≤1, 0≤y≤1, 0≤x+y≤1). For example, it may be one or more of n-type doped AlGaInN, GaN, AlGaN, InGaN, AlN, and InN. The first semiconductor layer (31) may be doped with an n-type dopant, and the n-type dopant may be Si, Ge, Sn, etc. For example, the first semiconductor layer (31) may be n-GaN doped with n-type Si. The length of the first semiconductor layer (31) may be in the range of 1.5 μm to 5 μm, but is not limited thereto.

[0157] The second semiconductor layer (32) may be disposed on the light-emitting layer (36) described later. The second semiconductor layer (32) may be a p-type semiconductor, and when the light-emitting element (30) emits light in the blue or green wavelength range, the second semiconductor layer (32) may include a semiconductor material having the chemical formula AlxGayIn1-x-yN (0≤x≤1, 0≤y≤1, 0≤x+y≤1). For example, it may be one or more of p-type doped AlGaInN, GaN, AlGaN, InGaN, AlN, and InN. The second semiconductor layer (32) may be doped with a p-type dopant, and the p-type dopant may be Mg, Zn, Ca, Se, Ba, etc. For example, the second semiconductor layer (32) may be p-GaN doped with p-type Mg. The length of the second semiconductor layer (32) may be in the range of 0.05㎛ to 0.10㎛, but is not limited thereto.

[0158] Meanwhile, the drawing shows the first semiconductor layer (31) and the second semiconductor layer (32) as being composed of a single layer, but is not limited thereto. Depending on the material of the light-emitting layer (36), the first semiconductor layer (31) and the second semiconductor layer (32) may further include a larger number of layers, such as a clad layer or a TSBR (Tensile strain barrier reducing) layer.

[0159] The light-emitting layer (36) may be disposed between the first semiconductor layer (31) and the second semiconductor layer (32). The light-emitting layer (36) may include a material having a single or multiple quantum well structure. If the light-emitting layer (36) includes a material having a multiple quantum well structure, it may have a structure in which a quantum layer and a well layer are alternately stacked in multiple layers. The light-emitting layer (36) may emit light by the coupling of electron-hole pairs according to an electrical signal applied through the first semiconductor layer (31) and the second semiconductor layer (32). If the light-emitting layer (36) emits light in the blue wavelength range, it may include a material such as AlGaN or AlGaInN. In particular, if the light-emitting layer (36) has a structure in which a quantum layer and a well layer are alternately stacked in a multiple quantum well structure, the quantum layer may include a material such as AlGaN or AlGaInN, and the well layer may include a material such as GaN or AlInN. For example, as described above, the light-emitting layer (36) may include AlGaInN as the quantum layer and AlInN as the well layer, and the light-emitting layer (36) may emit blue light having a central wavelength band in the range of 450 nm to 495 nm.

[0160] However, it is not limited thereto, and the light-emitting layer (36) may have a structure in which semiconductor materials with a large band gap energy and semiconductor materials with a small band gap energy are alternately stacked, and may include different Group 3 to Group 5 semiconductor materials depending on the wavelength range of the emitted light. The light emitted by the light-emitting layer (36) is not limited to light in the blue wavelength range, and may emit light in the red or green wavelength range depending on the case. The length of the light-emitting layer (36) may have a range of 0.05㎛ to 0.10㎛, but is not limited thereto.

[0161] Meanwhile, the light emitted from the light-emitting layer (36) can be emitted not only to the longitudinal outer surface of the light-emitting element (30) but also to both sides. The directionality of the light emitted from the light-emitting layer (36) is not limited to one direction.

[0162] The electrode layer (37) may be an ohmic contact electrode. However, it is not limited thereto and may be a Schottky contact electrode. The light-emitting element (30) may include at least one electrode layer (37). FIG. 4 illustrates the light-emitting element (30) including one electrode layer (37), but it is not limited thereto. Depending on the case, the light-emitting element (30) may include a larger number of electrode layers (37) or may omit them. The description of the light-emitting element (30) described below can be applied in the same way even if the number of electrode layers (37) changes or other structures are included.

[0163] The electrode layer (37) can reduce the resistance between the light-emitting element (30) and the electrode or contact electrode when the light-emitting element (30) is electrically connected to the electrode or contact electrode in a display device (10) according to one embodiment. The electrode layer (37) may include a conductive metal. For example, the electrode layer (37) may include at least one of aluminum (Al), titanium (Ti), indium (In), gold (Au), silver (Ag), ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), and ITZO (Indium Tin-Zinc Oxide). Additionally, the electrode layer (37) may include an n-type or p-type doped semiconductor material. The electrode layer (37) may include the same material or different materials, but is not limited thereto.

[0164] The insulating film (38) may be arranged to surround the outer surface of the plurality of semiconductor layers and electrode layers described above. For example, the insulating film (38) may be arranged to surround the outer surface of at least the light-emitting layer (36) and may extend in one direction in which the light-emitting element (30) extends. The insulating film (38) may perform the function of protecting the members. The insulating film (38) may be formed to surround the side portions of the members, but the two ends in the longitudinal direction of the light-emitting element (30) may be formed to be exposed.

[0165] In the drawing, the insulating film (38) is shown extending in the longitudinal direction of the light-emitting element (30) to cover from the first semiconductor layer (31) to the side of the electrode layer (37), but is not limited thereto. The insulating film (38) may cover only the outer surface of a portion of the semiconductor layer, including the light-emitting layer (36), or cover only a portion of the outer surface of the electrode layer (37), so that the outer surface of each electrode layer (37) is partially exposed. Additionally, the insulating film (38) may be formed with a rounded upper surface in cross-section in an area adjacent to at least one end of the light-emitting element (30).

[0166] The thickness of the insulating film (38) may be in the range of 10 nm to 1.0 μm, but is not limited thereto. Preferably, the thickness of the insulating film (38) may be around 40 nm.

[0167] The insulating film (38) may include materials having insulating properties, such as silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiOxNy), aluminum nitride (AlN), aluminum oxide (Al2O3), etc. Accordingly, it is possible to prevent an electrical short circuit that may occur when the light-emitting layer (36) comes into direct contact with an electrode through which an electrical signal is transmitted to the light-emitting element (30). In addition, since the insulating film (38) protects the outer surface of the light-emitting element (30) including the light-emitting layer (36), it is possible to prevent a decrease in light-emitting efficiency.

[0168] Additionally, the outer surface of the insulating film (38) may be surface-treated. The light-emitting element (30) may be sprayed onto the electrode and aligned in a dispersed state within a predetermined ink. Here, in order for the light-emitting element (30) to remain dispersed without aggregating with other adjacent light-emitting elements (30) within the ink, the surface of the insulating film (38) may be treated to be hydrophobic or hydrophilic. For example, the outer surface of the insulating film (38) may be surface-treated with a material such as stearic acid, 2,3-naphthalene dicarboxylic acid, etc.

[0169] Among the above-described display device (10), the first wavelength conversion unit (WLC1), the second wavelength conversion unit (WLC2), and the light transmission unit (LTU) can be formed by spraying onto a substrate (11) through a predetermined ink in a state where scatterers (SCT1, SCT2, SCT3) are dispersed in base resins (BS1, BS2, BS3) during the manufacture of the display device (10). In addition, the light-emitting element (30) of the display device (10) can also be aligned by spraying onto the substrate (11) in a state where it is dispersed within a predetermined ink.

[0170] The aforementioned scatterers (SCT1, SCT2, SCT3) and light-emitting elements (30) are composed of fine particles and can be dispersed in ink and sprayed onto a substrate (11). The ink is supplied through the inlet of the print head unit and, after being dispersed through the nozzles, the remaining ink is circulated through the outlet. However, the flow rate in the area adjacent to the outlet of the print head unit may be reduced compared to the area adjacent to the inlet, so that fine particles settle in the area adjacent to the outlet, and the number of fine particles in the ink sprayed through the nozzles may be reduced.

[0171] Below, an inkjet printing device for preventing the sedimentation of particles remaining in the print head unit and making the number of particles in the ink uniform will be described.

[0172] FIG. 6 is a schematic plan view of an inkjet printing device according to one embodiment. FIG. 7 is a schematic bottom view of a print head unit according to one embodiment. FIG. 8 is a schematic diagram showing the operation of a print head unit according to one embodiment. FIG. 9 is a schematic diagram showing a print head unit according to one embodiment.

[0173] Referring to FIGS. 6 to 9, an inkjet printing device (1000) according to one embodiment includes a print head unit (100) comprising a plurality of inkjet heads (300). The inkjet printing device (1000) may further include a stage (STA), an ink circulation unit (500), and a base frame (600).

[0174] An inkjet printing device (1000) can spray a predetermined ink (90) onto a target substrate (SUB) using a print head unit (100). The target substrate (SUB) can be provided on a stage (STA).

[0175] A stage (STA) can provide an area where a target substrate (SUB) is placed. An inkjet printing device (1000) includes a first rail (RL1) and a second rail (RL2) that extend in a second direction (DR2), and a stage (STA) is placed on the first rail (RL1) and the second rail (RL2). The stage (STA) can move in the second direction (DR2) via a separate moving member on the first rail (RL1) and the second rail (RL2). The stage (STA) can move in the second direction (DR2), pass through a print head unit (100), and ink (90) can be sprayed over it. However, it is not limited thereto. Although the drawing shows a structure in which the stage (STA) moves, in some embodiments, the stage (STA) may be fixed and the print head unit (100) may move. In this case, the print head unit (100) may be mounted on a frame positioned on the first rail (RL1) and the second rail (RL2).

[0176] A print head unit (100) may be disposed on a base frame (600) and may include a plurality of inkjet heads (300). The print head unit (100) may spray a predetermined ink (90) onto a target substrate (SUB) using an inkjet head (300) connected to a separate ink storage unit.

[0177] The base frame (600) may include a support member (610) and a moving unit (630). The support member (610) may include a first support member (611) extended in a first direction (DR1) which is horizontal, and a second support member (612) connected to the first support member (611) and extended in a third direction (DR3) which is vertical. The extension direction of the first support member (611) may be the same as the first direction (DR1). A print head unit (100) may be placed on a moving unit (630) mounted on the first support member (611).

[0178] The moving unit (630) may include a moving part (631) that is mounted on a first support part (611) and can move in one direction, and a fixed part (632) that is positioned on the lower surface of the moving part (631) and on which a print head unit (100) is positioned. The moving part (631) can move in a first direction (DR1) on the first support part (611), and the print head unit (100) can be fixed to the fixed part (632) and move in the first direction (DR1) together with the moving part (631).

[0179] A print head unit (100) is placed on a base frame (600) and can spray ink (90) provided from an ink reservoir onto a target substrate (SUB) through an inkjet head (300). The print head unit (100) may be spaced apart from a stage (STA) passing through the lower part of the base frame (600) at a specific distance. The distance at which the print head unit (100) is spaced apart from the stage (STA) can be adjusted by the height of the second support member (612) of the base frame (600). The distance between the print head unit (100) and the stage (STA) can be adjusted within a range such that when the target substrate (SUB) is placed on the stage (STA), the print head unit (100) has a certain distance from the target substrate (SUB) to secure the space required for the printing process.

[0180] According to one embodiment, the print head unit (100) may include an inkjet head (300) comprising a plurality of nozzles (350). The inkjet head (300) may be disposed on the lower surface of the print head unit (100).

[0181] A plurality of inkjet heads (300) may be spaced apart from each other in one direction and arranged in one column or multiple columns. In the drawing, the inkjet heads (300) are shown arranged in two columns, with the inkjet heads (300) in each column arranged staggered from each other. However, this is not limited thereto, and the inkjet heads (300) may be arranged in a larger number of columns and may be arranged to overlap rather than stagger. The shape of the inkjet heads (300) is not particularly limited, but as an example, the inkjet heads (300) may have a rectangular shape.

[0182] Inkjet heads (300) may be arranged adjacent to each other, for example, two inkjet heads (300) may form a pack. However, the number of inkjet heads (300) included in one pack is not limited thereto, and for example, the number of inkjet heads (300) included in one pack may be from one to five. Additionally, although only six inkjet heads (300) arranged in the print head unit (100) are shown in the drawing, this is for schematically illustrating the print head unit (100), and the number of inkjet heads (300) is not limited thereto.

[0183] An inkjet head (300) positioned in a print head unit (100) can spray ink (90) onto a target substrate (SUB) positioned on top of a stage (STA). According to one embodiment, the print head unit (100) can move in one direction on a first support member (611), and the inkjet head (300) can move in said one direction to spray ink (90) onto the target substrate (SUB).

[0184] The print head unit (100) can move in a first direction (DR1) in which the first support member (611) is extended, and the inkjet head (300) can move in the first direction (DR1) and spray ink (90) onto the target substrate (SUB).

[0185] In one embodiment, the ink (90) may comprise a solvent (91) and a plurality of particles (95) contained within the solvent (91). In an exemplary embodiment, the ink (90) may be provided in a solution or colloidal state. For example, the solvent (91) is acetone, water, alcohol, toluene, propylene glycol (PG) or propylene glycol methyl acetate (PGMA), triethylene glycol monobutyl ether (TGBE), diethylene glycol monophenyl ether (DGPE), amide solvent, dicarbonyl solvent, diethylene glycol dibenzoate, tricarbonyl solvent, triethyl citrate, phthalate solvent, benzyl butyl phthalate, bis(2-ethylhexyl) phthalate, bis(2-ethylhexyl) isophthalate, ethylphthalyl ethyl It may be glycolate (ethyl phthalyl ethyl glycolate), but is not limited thereto. A plurality of particles (95) may be contained in a dispersed state within a solvent (91) and supplied to a print head unit (100) to be discharged.

[0186] In some embodiments, the width of the target substrate (SUB) measured in the first direction (DR1) may be greater than the width of the print head unit (100). In this case, the print head unit (100) can move in the first direction (DR1) and spray ink (90) over the entire surface of the target substrate (SUB). Additionally, if multiple target substrates (SUB) are provided, the print head unit (100) can move in the first direction (DR1) and spray ink (90) onto each of the multiple target substrates (SUB).

[0187] However, not limited thereto, the print head unit (100) may be positioned outside the first rail (RL1) and the second rail (RL2) and then move in the first direction (DR1) to spray ink (90) onto the upper surface of the target substrate (SUB). When the stage (STA) moves in the second direction (DR2) and is positioned below the base frame (600), the print head unit (100) may move between the first rail (RL1) and the second rail (RL2) to spray ink (90) through the inkjet head (300). The operation of the inkjet head (300) is not limited thereto and may be modified in various ways within the range where a similar process can be implemented.

[0188] The inkjet printing device (1000) may further include an ink circulation unit (500). The ink circulation unit (500) can supply ink (90) to the print head unit (100), and the inkjet head (300) can discharge the supplied ink (90). The ink (90) circulates between the ink circulation unit (500) and the inkjet head (300), and some of the ink (90) supplied to the inkjet head (300) is discharged from the inkjet head (300), and the remainder can be supplied back to the ink circulation unit (500).

[0189] The ink circulation unit (500) can be connected to the inkjet head (300) through the first connecting pipe (IL1) and the second connecting pipe (IL2). For example, the ink circulation unit (500) can supply ink (90) to the inkjet head (300) through the first connecting pipe (IL1), and the flow rate of the supplied ink (90) can be controlled through the first valve (VA1). Additionally, the ink circulation unit (500) can supply the remainder of the ink (90) remaining after being discharged from the inkjet head (300) through the second connecting pipe (IL2). The flow rate of the ink (90) supplied to the ink circulation unit (500) through the second connecting pipe (IL2) can be controlled through the second valve (VA2). As the ink (90) is circulated through the ink circulation unit (500), the variation in the number of particles (95) contained in the ink (90) discharged from the inkjet head (300) can be minimized.

[0190] The ink circulation unit (500) may be mounted on the base frame (600), but is not limited thereto. The ink circulation unit (500) is provided in the inkjet printing device (1000), but its position or shape is not particularly limited. For example, the ink circulation unit (500) may be positioned via a separate device, and if connected to the inkjet head (300), various placements are possible within that range.

[0191] In some embodiments, the ink circulation unit (500) may include a first ink storage unit (510), a second ink storage unit (520), a third ink storage unit (530), a pressure pump (550), a compressor (560), and a flow meter (580). The ink circulation unit (500) may have the second ink storage unit (520), the pressure pump (550), and the third ink storage unit (530) connected to an inkjet head (300), and these may form an ink circulation system.

[0192] The first ink storage unit (510) may be a storage unit where manufactured ink (90) is prepared. Ink (90) containing a solvent (91) and particles (95) is prepared in the first ink storage unit (510) of the ink circulation unit (500), and the ink (90) may be supplied to the ink circulation system.

[0193] The second ink storage unit (520) is connected to the first ink storage unit (510) so that prepared ink (90) can be supplied. Additionally, the ink (90) remaining after being discharged from the inkjet head (300) can be supplied to the second ink storage unit (520) through the second connecting pipe (IL2). The second ink storage unit (520) can be positioned between the third ink storage unit (530), the inkjet head (300), and the first ink storage unit (510) to form an ink circulation system. If the second ink storage unit (520) is omitted, an excessive amount of ink (90) may be supplied to the third ink storage unit (530), and the dispersion of particles (95) may not be smooth. The ink circulation unit (500) may further include the second ink storage unit (520) to prevent an excessive amount of ink (90) from being supplied to the third ink storage unit (530). For example, the second ink storage unit (520) can serve as a buffer storage unit in which some of the ink (90) circulating in the ink circulation system is stored.

[0194] Ink (90) supplied to the second ink storage unit (520) can be supplied to the third ink storage unit (530) through a pressure pump (550). The pressure pump (550) may be a pump that transmits power to a fluid so that ink (90) can circulate within an ink circulation system. Ink (90) supplied to the second ink storage unit (520) can be supplied to the third ink storage unit (530) by the pressure pump (550). A flow meter (580) may be provided between the pressure pump (550) and the third ink storage unit (530), and the flow meter (580) can measure the flow rate of the ink (90) supplied to the third ink storage unit (530). The pressure pump (550) can adjust the flow rate of the ink (90) supplied to the third ink storage unit (530) according to the flow rate of the ink (90) measured by the flow meter (580).

[0195] Additionally, the ink circulation unit (500) is further equipped with a compressor (560), and the compressor (560) can regulate the pressure within the third ink storage unit (530). The compressor (560) can remove gas to create a vacuum inside the third ink storage unit (530) or introduce an external inert gas to maintain a constant pressure. However, it is not limited thereto, and the compressor (560) of the ink circulation unit (500) may be omitted.

[0196] The third ink storage unit (530) can be connected to the second ink storage unit (520) via a pressure pump (550) to supply ink (90). Additionally, the third ink storage unit (530) can supply ink (90) to an inkjet head (300) via a first connecting pipe (IL1). In one embodiment, the third ink storage unit (530) may include a stirrer (ST), and the stirrer (ST) can disperse particles (95) within the ink (90). As the stirrer (ST) rotates, the ink (90) supplied to the third ink storage unit (530) can maintain a dispersed state without the particles (95) settling. That is, the agitator (ST) of the third ink storage unit (530) can prevent the particles (95) from settling at the bottom of the third ink storage unit (530) and reducing the number of particles (95) in the ink (90) discharged through the inkjet head (300). The third ink storage unit (530) can supply ink (90) in which particles (95) are smoothly dispersed to the inkjet head (300), and the inkjet head (300) can discharge ink (90) containing particles (95) above a certain level.

[0197] Meanwhile, the inkjet printing device (1000) requires that the unit droplet amount of ink (90) discharged from the inkjet head (300) be constant, and at the same time, the number of particles (95) dispersed within the unit droplet amount needs to be uniformly controlled. While the ink (90) is discharged from the inkjet head (300) by the ink circulation system, if the number of particles (95) per unit droplet of ink (90) is not uniform, the reliability of the inkjet printing device (1000) may be compromised. This may cause a difference in brightness in the display device (10) and degrade the display quality.

[0198] According to one embodiment, the inkjet printing device (1000) can maintain the flow rate of the internal flow path through which the ink (90) is supplied by forming a slope on one surface of the base portion disposed on the inkjet head (300). Thus, the particles (95) dispersed within the ink (90) are prevented from settling, thereby maintaining a uniform number of particles (95) discharged into a unit space.

[0199] Below, the inkjet head (300) will be described in more detail.

[0200] FIG. 10 is a schematic cross-sectional view illustrating one example of an inkjet head according to one embodiment. FIG. 11 and FIG. 12 are schematic cross-sectional views illustrating other examples of an inkjet head according to one embodiment, respectively.

[0201] Referring to FIG. 10, the inkjet head (300) may include a plurality of nozzles (350) to discharge ink (90) through the nozzles (350). The ink (90) discharged from the nozzles (350) may be sprayed onto a target substrate (SUB) provided on a stage (STA). The nozzles (350) may be located on the bottom surface of the inkjet head (300) and may be arranged along one direction in which the inkjet head (300) extends.

[0202] The inkjet head (300) may include a base portion (310), an internal flow path (330), and a plurality of nozzles (350). The inkjet head (300) may further include an ejection portion (370).

[0203] The base portion (310) may form the main body of the inkjet head (300). The base portion (310) may be attached to the print head unit (100). The base portion (310) may have a shape extending in a first direction (DR1) and a second direction (DR2). However, it is not limited thereto, and the base portion (310) may have a circular or polygonal shape.

[0204] The discharge section (370) may be a portion of the base section (310) of the inkjet head (300) where a nozzle (350) is positioned. In the drawing, a discharge section (370) connected to the base section (310) and discharge sections (370) spaced apart therefrom are shown arranged, with a nozzle (350) formed between them. However, substantially, the discharge sections (370) may be a single integrated member without being spaced apart from each other, and the nozzle (350) may be formed in the shape of a hole penetrating the discharge section (370). That is, a plurality of discharge sections (370) may be formed as a single member without being spaced apart from each other. However, this is not limited thereto, and in some embodiments, the inkjet head (300) may have a plurality of units including a discharge section (370) with a nozzle (350) formed therein. In this case, multiple discharge sections (370) may be spaced apart from each other and connected to the base section (310).

[0205] The internal flow path (330) is positioned within the base section (310) so that ink (90) can be supplied from the ink circulation section (500). The print head unit (100) is supplied with ink (90) through a first connecting pipe (IL1) connected to the ink circulation section (500), and the ink (90) remaining after being discharged from the nozzle (350) can be supplied to the ink circulation section (500) through a second connecting pipe (IL2). The internal flow path (330) of the inkjet head (300) is supplied with ink (90) from the inlet (331) of the print head unit (100), and the ink (90) remaining after being discharged can be discharged through the outlet (333).

[0206] The base portion (310) may have a shape that extends in one direction, and the internal flow path (330) may be formed along the extension direction of the base portion (310). Ink (90) supplied through the print head unit (100) may flow through the internal flow path (330) and then be discharged through the nozzle (350) of the inkjet head (300).

[0207] A plurality of nozzles (350) may be disposed in a discharge section (370) located on one side of the base section (310), for example, the bottom surface. The plurality of nozzles (350) may be spaced apart from each other and arranged along the extension direction of the base section (310), and may discharge ink (90) by passing through the discharge section (370) of the base section (310) and connecting to the internal flow path (330). Although not shown in the drawing, the plurality of nozzles (350) may be arranged in one row or multiple rows. In addition, the number of nozzles (350) included in the inkjet head (300) may be 128 to 1800. The nozzles (350) may discharge ink (90) that has flowed in along the internal flow path (330). The amount of ink (90) discharged once from each nozzle (350) may be 1 to 50 pl (Pico-litter), but is not limited thereto.

[0208] In the ink (90) discharged from the inkjet head (300), a plurality of particles (95) are dispersed. The ink (90) discharged once from the nozzle (350) may contain a specific number of particles (95) depending on the degree of dispersion of the particles (95). In the internal flow path (330) within the inkjet head (300), the flow rate of the ink (90) gradually decreases as it moves from the inlet (331) to the outlet (333), so that the particles (95) may settle in the internal flow path (330) adjacent to the outlet (333). Accordingly, the degree of dispersion of the particles (95) in the ink (90) is not maintained at a constant level, and the number of particles (95) in the ink (90) discharged once may vary.

[0209] According to one embodiment, the base portion (310) may have an inclination on one surface that contacts the internal flow path (330). The base portion (310) may include a first surface (312) that contacts the internal flow path (330). The first surface (312) of the base portion (310) may be a surface that forms the internal flow path (330). The first surface (312) may have a predetermined inclination in a first direction (DR1).

[0210] Specifically, the first surface (312) of the base portion (310) may be spaced apart by a predetermined distance from one surface of the discharge portion (370), that is, the surface where the discharge portion (370) faces the base portion (310). The said distance may be the diameter in the third direction (DR3) of the internal flow path (330). In the direction perpendicular to the discharge portion (370), that is, in the third direction (DR3), the distance from a point on the first surface (312) of the base portion (310) to the discharge portion (370) may be spaced apart by a first distance (d1). A point on the first surface (312) of the base portion (310) may be one side of the base portion (310) adjacent to the inlet (331) where the ink (90) is supplied. Additionally, in a third direction (DR3) perpendicular to the discharge section (370), the discharge section (370) may be spaced apart by a second distance (d2) from another point on the first surface (312) of the base section (310). The other point on the first surface (312) of the base section (310) may be the other side of the base section (310) adjacent to the outlet (333) from which the ink (90) is discharged.

[0211] By having a slope on the first surface (312) of the base portion (310), the first distance (d1) can be made longer than the second distance (d2). That is, the diameter of the inner channel (330) adjacent to the inlet (331) can be made larger than the diameter of the inner channel (330) adjacent to the outlet (333). As described above, the flow rate of the ink (90) supplied from the inlet (331) can decrease as it moves toward the outlet (333). When the flow rate decreases, the particles (95) contained in the ink (90) settle within the inner channel (330) adjacent to the outlet (333), and this can cause a decrease in the number of particles (95) discharged from the nozzle (350) adjacent to the outlet (333).

[0212] In one embodiment, the second distance (d2) can be formed shorter than the first distance (d1). That is, the diameter of the inner channel (330) adjacent to the outlet is formed smaller than the diameter of the inner channel (330) adjacent to the inlet (331), thereby preventing a decrease in the flow rate of the ink (90) and maintaining a constant flow rate. Accordingly, particles (95) can be discharged through the nozzles (350) without settling in the inner channel (330) adjacent to the outlet (333).

[0213] The second distance (d2) can be 90% to 99% of the first distance (d1). If the second distance (d2) is 99% or less of the first distance (d1), the flow rate of the ink (90) can be prevented from decreasing, and if the second distance (d2) is 90% or more of the first distance (d1), the amount of ink (90) discharged through the nozzles (350) can be prevented from decreasing.

[0214] In some embodiments, the distance between the first surface (312) and the discharge section (370) can be gradually reduced from one side of the first surface (312) of the base section (310) to the other. In other words, the diameter of the internal flow path (330) adjacent to the inlet (331) can be gradually reduced as it moves toward the outlet (333). Thus, the flow rate of the ink (90) can be prevented from decreasing and the flow rate can be maintained at a constant level.

[0215] Meanwhile, the first surface (312) of the base portion (310) may be provided with a protrusion (315) to have an incline.

[0216] Referring to FIG. 11, a protrusion (315) may be disposed on the other side adjacent to the outlet (333) of the first surface (312) of the base portion (310). The protrusion (315) may have a slope with increasing thickness as it moves toward the second direction (DR2). The protrusion (315) may be disposed on the first surface (312) adjacent to the outlet (333) to reduce the diameter of the internal flow path (330).

[0217] In one embodiment, the distance between a point on the protrusion (315) and a surface of the discharge section (370) may be spaced apart by a third distance (d3). A point on the protrusion (315) may be a side of the protrusion (315) adjacent to the outlet (333), and a surface of the discharge section (370) may be a surface facing the protrusion (315). The first distance (d1) described above may be longer than the third distance (d3), that is, the third distance (d3) may be shorter than the first distance (d1). Accordingly, the flow rate of the ink (90) in the area adjacent to the outlet (333) is prevented from decreasing, thereby maintaining a constant flow rate so that particles (95) can be discharged through the nozzles (350) without settling in the internal flow path (330) adjacent to the outlet (333).

[0218] Additionally, referring to FIG. 12, as another example, the protrusion (315) may have a 90-degree inclination. The protrusion (315) may be formed in the shape of a rectangular bar and may be positioned apart from the discharge portion (370) by a third distance (d3). However, it is not limited thereto, and the shape of the protrusion (315) may be formed in the shape of a polygonal prism or a lenticular lens, and any shape is possible as long as the distance between the first surface (312) of the base portion (310) and the discharge portion (370) can be reduced.

[0219] In the drawing, the protrusion (315) is shown as being provided as an additional component on the first surface (312) of the base part (310), but it is not limited thereto, and the protrusion (315) may be formed as one body with the base part (310).

[0220] FIG. 13 is a schematic cross-sectional view of an inkjet head according to another embodiment.

[0221] Referring to FIG. 13, the inkjet head (300) may have a first surface (312) of the base portion (310) that is inclined. In other embodiments, there is a difference from the embodiments of FIG. 10 to 12 described above in that the diameters of the nozzles (350) are different from each other. Below, the differences will be explained in detail, and the description of identical configurations will be omitted.

[0222] An inkjet head (300) according to one embodiment may include a plurality of nozzles (350). The plurality of nozzles (350) may include a first nozzle (352) adjacent to an inlet (331) and a second nozzle (353) adjacent to an outlet (333). The first nozzle (352) and the second nozzle (353) may have a predetermined diameter so that ink (90) can be discharged. The diameters of the nozzles (352, 353) may be diameters in a first direction (DR1).

[0223] The diameter (D1) of the first nozzle (352) may be larger than the diameter (D2) of the second nozzle (353), or in other words, the diameter (D2) of the second nozzle (353) may be smaller than the diameter (D1) of the first nozzle (352). That is, the diameter (D1) of the first nozzle (352) adjacent to the inlet (331) may be larger than the diameter (D2) of the second nozzle (353) adjacent to the outlet (333). As described above, the flow rate of the ink (90) supplied from the inlet (331) may decrease as it moves toward the outlet (333). When the flow rate decreases, the particles (95) contained in the ink (90) settle within the internal flow path (330) adjacent to the outlet (333), and this may cause a decrease in the number of particles (95) discharged from the nozzle (350) adjacent to the outlet (333).

[0224] In one embodiment, the diameter (D2) of the second nozzle (353) can be formed smaller than the diameter (D1) of the first nozzle (352). That is, by forming the diameter (D2) of the second nozzle (353) adjacent to the outlet (333) smaller than the diameter (D1) of the first nozzle (352) adjacent to the inlet (331), the flow rate of the ink (90) discharged through the second nozzle (353) is prevented from decreasing, thereby maintaining a constant flow rate. Accordingly, particles (95) can be discharged through the second nozzle (353) without settling in the internal flow path (330) adjacent to the outlet (333).

[0225] The diameter (D2) of the second nozzle (353) can be 90% to 99% of the diameter (D1) of the first nozzle (352). If the diameter (D2) of the second nozzle (353) is 99% or less of the diameter (D1) of the first nozzle (352), the flow rate of the ink (90) can be prevented from decreasing, and if the diameter (D2) of the second nozzle (353) is 90% or more of the diameter (D1) of the first nozzle (352), the amount of ink (90) discharged through the nozzles (350) can be prevented from decreasing.

[0226] Additionally, the discharge section (370) may further include a third nozzle (354) adjacent to the second nozzle (353). The third nozzle (354) may be positioned closer to the inlet (331) than the second nozzle (353). The third nozzle (354) may have a predetermined diameter (D3) and may be larger than the diameter (D2) of the second nozzle (353). Since the flow rate of the ink (90) supplied to the internal flow path (330) may decrease as it moves toward the outlet (333), the diameter (D3) of the third nozzle (354) adjacent to the inlet (331) than the second nozzle (353) may be larger than the diameter (D2) of the second nozzle (353). However, since there is no reduction in flow velocity at the first nozzle (352) closest to the inlet (331), the diameter (D1) of the first nozzle (352) is made the largest, and the diameter (D3) of the third nozzle (354) can be made smaller than the diameter (D1) of the first nozzle (352).

[0227] In some embodiments, the diameter of the nozzles (350) may gradually decrease from the inlet (331) to the outlet (333). Thus, the flow rate of the ink (90) can be kept constant by preventing the flow rate from gradually decreasing.

[0228] FIG. 14 is a schematic cross-sectional view of an inkjet head according to another embodiment. FIG. 15 is a schematic plan view of one example of the bottom surface of a base part and a rotating member according to another embodiment. FIG. 16 is a schematic plan view of another example of the bottom surface of a base part and a rotating member according to another embodiment.

[0229] Referring to FIGS. 14 and 15, the inkjet head (300) may include a base portion (310), an ejection portion (370), and an internal flow path (330). In another embodiment, there is a difference from the embodiment of FIGS. 10 to 12 described above in that the base portion (310) has no inclination and the internal flow path (330) includes a rotating member (700). Below, the differences will be described in detail, and the description of identical configurations will be omitted.

[0230] In one embodiment, a rotating member (700) may be disposed in the internal channel (330). The rotating member (700) may passively rotate according to the flow of ink (90) to mix the ink (90) supplied to the internal channel (330). The rotational speed of the rotating member (700) may be substantially the same as the flow rate of the ink (90).

[0231] Specifically, the rotating member (700) may include a rotating shaft (710) fixed to the base portion (310) and a wing (720) coupled to the rotating shaft (710) and rotating in one direction. The rotating shaft (710) may be positioned on one side of the base portion (310) facing the discharge portion (370). The rotating shaft (710) may be positioned at the center of one side of the base portion (310). The wing (720) may consist of a left and right pair extending horizontally around the rotating shaft (710). Although the drawing shows the wing (720) as consisting of a left and right pair, it is not limited thereto and may consist of two or more pairs. Additionally, the wing (720) may consist of an odd number of separate wings, such as three or five, rather than pairs.

[0232] The wing (720) may have a predetermined length to facilitate mixing of the ink (90) moving through the internal channel (330). The length (L1) of the wing (720) may be shorter than the length (L2) to one side of the base portion (310) relative to the axis of rotation (710). The radius of rotation of the wing (720) may be determined by the length (L1) of the wing (720), and the wing (720) may not protrude beyond one side of the base portion (310) so that the wing (720) does not interfere with other structures, such as the side walls of the internal channel (330). In some embodiments, the length (L1) of the wing (720) may be substantially the same as the length (L2) to one side of the base portion (310) relative to the axis of rotation (710).

[0233] Referring to FIG. 16, the rotating member (700) provided in the base portion (310) may be composed of a plurality of members. The rotating member (700) may include a first rotating member (740) disposed at the center of the base portion (310) and second rotating members (750a, 750b, 750c, 750d) disposed at at least one corner of the base portion (310).

[0234] The first rotating member (740) includes a wing having a predetermined length and can rotate with a predetermined radius of rotation. The second rotating members (750a, 750b, 750c, 750d) are positioned in an area other than the radius of rotation of the first rotating member (740) to mix ink (90). Each of the second rotating members (750a, 750b, 750c, 750d) may be made smaller in size than the first rotating member (740). Here, the size of the rotating member refers to the diameter of the rotation axis (710) and the length of the wing (720). The second rotating members (750a, 750b, 750c, 750d) are made relatively small in size so that they can mix ink (90) in an area other than the radius of rotation of the first rotating member (740).

[0235] The inkjet head (300) of the inkjet printing device according to the above-described embodiment includes a rotating member (700) so as to mix the ink (90) moving through the internal flow path (330). A plurality of particles (95) contained in the ink (90) are mixed by the rotating member (700) and supplied to each nozzle (350), so that they can be uniformly discharged without settling within the internal flow path (330).

[0236] FIG. 17 is a schematic cross-sectional view of an inkjet head according to another embodiment. FIG. 18 is a schematic cross-sectional view showing the vibration of a sedimentation prevention member and particles. FIG. 19 is a schematic diagram showing the charged state of particles. FIG. 20 is a schematic cross-sectional view of an inkjet head according to another embodiment.

[0237] Referring to FIG. 17, the inkjet head (300) may include a base portion (310), an ejection portion (370), and an internal flow path (330). In another embodiment, the inkjet head (300) differs from the embodiments of FIG. 14 to 16 described above in that it includes a sedimentation prevention member (800) on the side wall portion (1100). Below, the differences will be described in detail, and the description of identical configurations will be omitted.

[0238] In one embodiment, the inkjet head (300) may further include a sidewall portion (1100) forming a sidewall of the internal flow path (330). The sidewall portion (1100) may be positioned adjacent to the base portion (310) with the internal flow path (330) in between. The sidewall portion (1100) may extend in a third direction (DR3) from the discharge portion (370).

[0239] The side wall portion (1100) may include a first side wall portion (1110) extending from the discharge portion (370) and contacting the inlet (331), and a second side wall portion (1120) extending from the discharge portion (370) and contacting the outlet (333). The first side wall portion (1110) and the second side wall portion (1120) are spaced apart from each other with the base portion (310) in between, and may be arranged side by side.

[0240] The side wall portion (1100) may include a sedimentation prevention member (800) capable of mixing a plurality of particles (95) mixed in the ink (90). Specifically, the sedimentation prevention member (800) may include a first sedimentation prevention member (810) and a second sedimentation prevention member (820). The first sedimentation prevention member (810) may be placed in the first side wall portion (1110), and the second sedimentation prevention member (820) may be placed in the second side wall portion (1120). Each sedimentation prevention member (810, 820) may be inserted into each side wall portion (1110, 1120) so as not to obstruct the movement of the ink (90) moving through the internal flow path (330). One side of each sedimentation prevention member (810, 820) may be exposed to the internal flow path (330). One side of each sedimentation prevention member (810, 820) can come into contact with ink (90) moving through the internal flow path (330).

[0241] In one embodiment, the sedimentation prevention member (810, 820) may be an ultrasonic vibrator. The ultrasonic vibrator can generate ultrasonic vibrations in one direction to vibrate the ink (90) moving through the internal flow path (330). The ink (90) may vibrate up and down or vibrate left and right in a plane by the ultrasonic waves generated by the ultrasonic vibrator.

[0242] The ultrasonic transducer may be composed of a converter capable of converting AC power into ultrasonic vibrations. Additionally, the ultrasonic transducer may be composed of a piezoelectric element capable of converting electrical signals into vibration signals. The power required to apply ultrasonic vibrations may be supplied from an external power supply. Furthermore, along with the external power supply, a display may be provided that shows the ultrasonic frequency and amplitude, etc., as digital values ​​or waveform curves.

[0243] As illustrated in FIG. 18, ultrasonic vibrations can be generated in a first direction (DR1) from a first sedimentation prevention member (810) composed of an ultrasonic vibrator, and ultrasonic vibrations can be generated in a direction opposite to the first direction (DR1) from a second sedimentation prevention member (820). The ink (90) and the particles (95) mixed in the ink (90) can be mixed by vibrating each other or left and right by ultrasonic vibrations.

[0244] As described above, a plurality of particles (95) contained in the ink (90) can be mixed by ultrasonic vibration by providing a sedimentation prevention member (800) of the ultrasonic vibrator. Accordingly, the particles (95) are supplied to each nozzle (350) without settling within the internal flow path (330), thereby allowing the number of particles (95) to be discharged uniformly.

[0245] Referring to FIGS. 17 and 19, in another embodiment, the sedimentation prevention member (810, 820) may be a charging plate. The charging plate may be an electrode to which a positive voltage or a negative voltage is applied. The charging plate may charge the particles (95) of the ink (90) in contact with the charging plate as (+) or (-). The ink (90) may generate repulsion between the particles (95) by being charged as the same (+) or (-). The power required to charge the particles (95) may be supplied to the charging plate from an external power supply.

[0246] Referring to FIG. 20, in another embodiment, the first sedimentation prevention member (810) may be provided only on the second sidewall (1120). As described above, since the flow velocity in the internal flow path (330) adjacent to the outlet (333) is reduced and sedimentation of particles (95) may occur, the sedimentation prevention member (810) may be provided on the second sidewall (1120) adjacent to the outlet (333) to prevent sedimentation of particles (95). However, this is not limited thereto, and the first sedimentation prevention member (810) may be provided only on the first sidewall (1110) adjacent to the inlet (331).

[0247] The inkjet head (300) of the inkjet printing device according to the above-described embodiment includes a sedimentation prevention member (800) so as to disperse particles (95) of the ink (90) moving through the internal flow path (330). A plurality of particles (95) contained in the ink (90) are dispersed by the sedimentation prevention member (800) and supplied to each nozzle (350), so that the number of particles (95) can be uniformly discharged without settling within the internal flow path (330). Accordingly, by making the number of particles (95) per unit droplet of ink (90) uniform, it is possible to prevent a difference in brightness from occurring in the display device (10).

[0248] Although embodiments of the present invention have been described above with reference to the attached drawings, those skilled in the art will understand that the present invention may be implemented in other specific forms without changing the technical concept or essential features thereof. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. Explanation of the symbols

[0249] 90: Ink 95: Particles 300: Inkjet head 310: Base part 315: Protrusion 330: Internal Euro 331: Entrance 333: Exit 350: Nozzle 370: Discharge section 700: Rotating member 710: Rotation axis 720: Wing 800: Anti-sedimentation member

Claims

Claim 1 An inkjet printing device comprising: a stage; and an inkjet head located above the stage and comprising a plurality of nozzles for discharging ink containing a plurality of particles, wherein the inkjet head comprises: a base portion constituting the main body of the inkjet head; a discharge portion disposed adjacent to the base portion and having the plurality of nozzles disposed therein; and an internal flow path through which the ink is supplied between the base portion and the discharge portion, wherein the base portion comprises a first surface in contact with the internal flow path, at least a portion of the first surface has an incline, the entire surface of the internal flow path in contact with the discharge portion is flat, and the distance between the first surface and the discharge portion decreases linearly as one side of the first surface of the base portion moves from one side to the other. Claim 2 An inkjet printing device according to claim 1, wherein, between the first surface of the base part and the discharge part, there is a first distance from one point on the first surface to the discharge part in a direction perpendicular to the discharge part, and a second distance from another point on the first surface to the discharge part, wherein the first distance is longer than the second distance. Claim 3 In claim 2, the inkjet head further comprises an inlet through which the ink is supplied to the internal flow path and an outlet through which the ink is discharged, wherein the first distance is adjacent to the inlet and the second distance is adjacent to the outlet, an inkjet printing device. Claim 4 In claim 3, an inkjet printing device wherein the second distance is 90% to 99% of the first distance. Claim 5 delete Claim 6 In claim 3, the plurality of nozzles includes a first nozzle adjacent to the inlet and a second nozzle adjacent to the outlet, wherein the diameter of the first nozzle is larger than the diameter of the second nozzle, an inkjet printing device. Claim 7 An inkjet printing device according to claim 6, wherein the diameter of the second nozzle is 90% to 99% of the diameter of the first nozzle. Claim 8 An inkjet printing device according to claim 6, wherein the plurality of nozzles further comprises a third nozzle disposed between the first nozzle and the second nozzle and disposed adjacent to the second nozzle, and the diameter of the third nozzle is larger than that of the second nozzle and smaller than that of the first nozzle. Claim 9 In claim 3, an inkjet printing device in which the diameter of the internal flow path adjacent to the outlet is smaller than the diameter of the internal flow path adjacent to the inlet. Claim 10 In claim 3, an inkjet printing device in which the diameter of the internal channel adjacent to the outlet gradually decreases toward the outlet. Claim 11 delete Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 delete Claim 16 delete Claim 17 delete Claim 18 delete Claim 19 delete Claim 20 delete

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