Inkjet printing apparatus

Abstract

The present disclosure relates to an inkjet printing apparatus including a stage and an inkjet head located above the stage and including a plurality of nozzles through which ink including a plurality of particles is discharged. The inkjet head includes a base constituting a main body of the inkjet head, a discharge portion adjacent to the base and including the plurality of nozzles, and an internal flow path between the base and the discharge portion and configured to accommodate the ink, wherein the base includes a first surface contacting the internal flow path, and at least a portion of the first surface is inclined.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2020-0131945, filed on October 13, 2020, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] One or more embodiments of this disclosure relate to an inkjet printing apparatus. Background Technology

[0004] With the development of multimedia, display devices are becoming increasingly important. Therefore, various display devices such as organic light-emitting diodes (OLEDs) and / or liquid crystal displays (LCDs) are being used.

[0005] A display device is a device for displaying images and includes display panels such as organic light-emitting display panels and / or liquid crystal display panels. As a light-emitting display panel, the display panel may include light-emitting elements such as light-emitting diodes (LEDs). For example, an LED may be an organic light-emitting diode (OLED) that uses (e.g., utilizes) organic materials as light-emitting materials, or it may be an inorganic LED that uses (e.g., utilizes) inorganic materials as light-emitting materials.

[0006] For example, an inkjet printing apparatus can be used to form an organic material layer included in a display device or to form an inorganic light-emitting diode. After printing any ink or solution by inkjet printing, a post-processing process can be performed to transfer the inorganic light-emitting diode or form the organic material layer. In an inkjet printing apparatus, a set or predetermined ink or solution can be supplied to an inkjet head, and the inkjet head can perform a process of jetting the ink or solution onto a substrate to be processed (e.g., a target substrate). Summary of the Invention

[0007] One or more aspects of embodiments of this disclosure are to provide an inkjet printing apparatus for reducing or preventing the deposition of particles remaining in a printhead unit, thereby making the number of particles in the ink uniform (or substantially uniform).

[0008] One or more aspects of the embodiments of this disclosure are to provide an inkjet printing apparatus that can reduce or prevent the occurrence of spots due to brightness differences in display devices.

[0009] According to one or more embodiments of the present disclosure, an inkjet printing device includes a stage and an inkjet head above the stage and including a plurality of nozzles through which ink including a plurality of particles is expelled, wherein the inkjet head includes a base constituting a main body of the inkjet head, a discharge portion adjacent to the base and including the plurality of nozzles, and an internal flow path between the base and the discharge portion and configured to contain the ink, wherein the base includes a first surface contacting the internal flow path, and at least a portion of the first surface is inclined.

[0010] In one or more embodiments, a first distance from a point of the first surface of the base to the discharge portion is longer than a second distance from another point of the first surface to the discharge portion.

[0011] In one or more embodiments, the inkjet head further includes an inlet through which the ink is supplied and an outlet through which the ink is discharged, the inlet and the outlet are in the internal flow path, and the point of the first surface is on a side of the base adjacent to the inlet, and the other point of the first surface is on another side of the base adjacent to the outlet.

[0012] In one or more embodiments, the second distance is about 90% to about 99% of the first distance.

[0013] In one or more embodiments, a distance between the first surface and the discharge portion gradually decreases from one end of the first surface of the base toward another end thereof.

[0014] In one or more embodiments, the plurality of nozzles includes a first nozzle adjacent to the inlet and a second nozzle adjacent to the outlet, and a diameter of the first nozzle is greater than a diameter of the second nozzle.

[0015] In one or more embodiments, the diameter of the second nozzle is about 90% to about 99% of the diameter of the first nozzle.

[0016] In one or more embodiments, the plurality of nozzles further includes a third nozzle between the first nozzle and the second nozzle, the third nozzle is adjacent to the second nozzle, and a diameter of the third nozzle is greater than the diameter of the second nozzle and less than the diameter of the first nozzle.

[0017] In one or more embodiments, a portion of the internal flow path adjacent to the outlet has a diameter that is less than a diameter of a portion of the internal flow path adjacent to the inlet.

[0018] In one or more embodiments, a diameter of the internal flow path gradually decreases from the inlet toward the outlet.

[0019] However, aspects of the present disclosure are not limited to the aspects set forth herein. The above and other aspects of the present disclosure will become more apparent to those skilled in the art from the following detailed description of the present disclosure, given by way of example. Attached Figure Description

[0020] The above and other aspects and features of this disclosure will become more apparent from the accompanying drawings, which describe embodiments of the present disclosure in more detail, in which:

[0021] Figure 1 It is a schematic plan view of a display device according to one or more embodiments;

[0022] Figure 2 It is a schematic cross-sectional view showing some sub-pixels of a display device according to one or more embodiments;

[0023] Figure 3 It is a plan view showing a pixel of a display device according to one or more embodiments;

[0024] Figure 4 It is along Figure 3 A cross-sectional view taken by lines Q1-Q1', Q2-Q2', and Q3-Q3';

[0025] Figure 5 This is a schematic diagram of a light-emitting element according to one or more embodiments;

[0026] Figure 6 It is a schematic plan view of an inkjet printing apparatus according to one or more embodiments;

[0027] Figure 7 This is a schematic bottom view of a printhead unit according to one or more embodiments;

[0028] Figure 8 This is a schematic diagram illustrating the operation of a printhead unit according to one or more embodiments;

[0029] Figure 9 This is a schematic diagram illustrating a printhead unit according to one or more embodiments;

[0030] Figure 10 This is a schematic cross-sectional view showing an example of an inkjet head according to one or more embodiments;

[0031] Figure 11 and Figure 12 These are cross-sectional views schematically illustrating other examples of inkjet heads according to one or more embodiments;

[0032] Figure 13 It is a schematic cross-sectional view of an inkjet head according to one or more other embodiments;

[0033] Figure 14 It is a schematic cross-sectional view of an inkjet head according to one or more other embodiments;

[0034] Figure 15 is a plan view schematically showing an example of a bottom surface of a base and a rotating member according to one or more other embodiments;

[0035] Figure 16 is a plan view schematically showing another example of a bottom surface of a base and a rotating member according to one or more other embodiments;

[0036] Figure 17 is a schematic cross-sectional view of an inkjet head according to one or more other embodiments;

[0037] Figure 18 is a cross-sectional view schematically showing a state in which a deposition-preventing member and particles are vibrated;

[0038] Figure 19 is a view schematically showing a state in which particles are charged; and

[0039] Figure 20 is a schematic cross-sectional view of an inkjet head according to one or more other embodiments. DETAILED DESCRIPTION

[0040] The present disclosure will now be described more fully with reference to the accompanying drawings, in which embodiments of the present disclosure are shown. The present disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0041] It will also be understood that when a layer is referred to as being "on" another layer or substrate, it can be directly on the other layer or substrate (e.g., with no intervening layers), or intervening layers can also be present. Throughout the specification, like reference numerals refer to like elements.

[0042] It will be understood that, although the terms "first", "second", etc. can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element discussed below could be termed a second element without departing from the teachings of the present application. Similarly, a second element could be termed a first element.

[0043] Each of the features of the various embodiments of the present disclosure can be partially or wholly combined with each other, and technically various interlocks and drives are possible. Each embodiment can be realized independently of one another, or can be realized in association with one another.

[0044] As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0045] It will be further understood that the terms “comprises” and / or “comprising,” when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0046] As used herein, the terms “use,” “using,” and “used” can be considered synonymous with and interchangeable with the terms “utilize,” “utilizing,” and “utilized,” respectively.

[0047] As used herein, expressions such as “at least one of,” “one or more of,” and “selected from the group consisting of,” when preceding the list of elements, modify the entire list of elements and do not modify the individual elements of the list.

[0048] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0049] In addition, the use of “may” when describing embodiments of the present disclosure means that one or more embodiments of the present disclosure.

[0050] As used herein, the terms “substantially,” “approximately,” and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent deviations in measured or calculated values that would be recognized by those of ordinary skill in the art. As used herein, “about” or “approximately” includes the stated value and the average value within an acceptable range of deviation as determined by one of ordinary skill in the art in consideration of measurements and the error in the measurements associated with the particular amount being measured (i.e., limitations of the measurement system). For example, “about” can mean within one or more standard deviations, or within ± 30%, ± 20%, ± 10%, ± 5% of the stated value.

[0051] Any numerical range recited herein is intended to include all sub-ranges of the same entire number precision, i.e. one having the same number of decimal places as the numerical range. As an example, a range from 1.0 to 10.0 should be read to include the range from 2.4 to 7.6, not just from 1.0 to 10.0. Any maximum numerical limitation recited herein is intended to include all lower numerical limitations subsumed therein and any minimum numerical limitation recited herein is intended to include all higher numerical limitations subsumed therein. Accordingly, Applicant reserves the right to amend the specification, including the claims, to expressly recite any sub-range subsumed within the ranges expressly recited in the specification.

[0052] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0053] Figure 1 is a schematic plan view of a display apparatus according to one or more embodiments.

[0054] Referring to Figure 1 The display apparatus 10 displays a moving (e.g., motion) image or a still image. The display apparatus 10 can refer to any electronic apparatus that provides a display screen. For example, the display apparatus 10 can be used in a television, a notebook, a monitor, a billboard, an Internet of Things apparatus, a mobile phone, a smart phone, a tablet personal computer (PC), an electronic watch, a smart watch, a watch phone, a head-mounted display, a mobile communication terminal, an electronic notebook, an electronic book, a portable multimedia player (PMP), a navigator, a game machine, a digital camera, a camcorder, etc.

[0055] The display apparatus 10 includes a display panel for providing a display screen. Examples of the display panel can include an inorganic light emitting diode display panel, an organic light emitting display panel, a quantum dot light emitting display panel, a plasma display panel, and a field emission display panel. Hereinafter, a case where an inorganic light emitting diode display panel is used as the display panel will be exemplified, but the present disclosure is not limited thereto. Any suitable display panel can be used as the display panel as long as the same technical idea is applicable.

[0056] In the drawing showing 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 can be directions perpendicular (e.g., substantially perpendicular) to each other in one plane. The third direction DR3 can be a direction perpendicular (e.g., substantially perpendicular) to the plane in which the first direction DR1 and the second direction DR2 lie. The third direction DR3 is perpendicular (e.g., substantially perpendicular) to each of the first direction DR1 and the second direction DR2. In describing one or more embodiments of the display device 10, the third direction DR3 refers to a thickness direction of the display device 10.

[0057] The shape of the display device 10 can be variously modified as appropriate. For example, in a plan view, the display device 10 can have a rectangular shape including a side longer in the first direction DR1 than in the second direction DR2. For another example, in a plan view, the display device 10 can have a rectangular shape including a side longer in the second direction DR2 than in the first direction DR1. However, the present disclosure is not limited thereto, and the display device 10 can have a shape such as a square, a rectangle with rounded corners (apexes), another polygon, and / or a circle, without limitation. The shape of the display area DPA of the display device 10 can also be similar to the overall shape of the display device 10. Figure 1 The display device 10 and the display area DPA are shown each having a rectangular shape including a side longer in the first direction DR1 than in the second direction DR2.

[0058] The display device 10 can include a display area DPA and a non-display area NDA. The display area DPA is an area in which an image is displayed, and the non-display area NDA is an area in which an image is not displayed. The display area DPA can be referred to as an active area, and the non-display area NDA can be referred to as an inactive area. The display area DPA can generally occupy the center of the display device 10.

[0059] The display area DPA can include a plurality of pixels PX. The plurality of pixels PX can be arranged in a matrix direction (e.g., matrix-formed). In a plan view, each of the pixels PX can have a rectangular shape or a square shape, but its shape is not limited thereto. For example, each of the pixels PX can have a diamond shape in which each side is inclined with respect to one direction. The respective pixels PX can be arranged in a stripe pattern or a mosaic pattern. The pattern or the arrangement of the pixels PX is not limited to the above-described examples. Each of the pixels PX includes at least one light emitting element 30 that emits (e.g., is configured to emit) light of a set or specific wavelength band to display a set or specific color.

[0060] The non-display area NDA can be around the display area DPA. The non-display area NDA can completely or partially surround the display area DPA. The display area DPA can have a rectangular shape, and the non-display area NDA can be adjacent to four sides of the display area DPA. The non-display area NDA can constitute a bezel of the display apparatus 10. Wires and / or circuit drivers included in the display apparatus 10 can be located in the non-display area NDA, and / or external apparatuses can be mounted in the non-display area NDA.

[0061] Figure 2 is a schematic cross-sectional view illustrating some sub-pixels of a display apparatus according to one or more embodiments.

[0062] Referring to Figure 2 The display area DPA of the display apparatus 10 can include a first light emitting area LA1, a second light emitting area LA2, and a third light emitting area LA3. Each of the first light emitting area LA1, the second light emitting area LA2, and the third light emitting area LA3 can be an area in which light generated from the light emitting element 30 of the display apparatus 10 is emitted to the outside of the display apparatus 10.

[0063] The display apparatus 10 can 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 a thin film encapsulation layer TFE.

[0064] The substrate 11 can be a base substrate or a base member, and can be made of an insulating material such as a polymer resin. For example, the substrate 11 can be a flexible substrate that can be bent, folded, rolled, etc. The substrate 11 can include polyimide (PI), but its material is not limited thereto.

[0065] The buffer layer 12 can be on the substrate 11. The buffer layer 12 can be formed of an inorganic layer capable of reducing or preventing air and / or moisture penetration. For example, the buffer layer 12 can include a plurality of inorganic layers alternately stacked.

[0066] The transistor layer TFTL can be on the buffer layer 12. The transistor layer TFTL can 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 planarization layer 19.

[0067] The first transistor T1 can be on the buffer layer 12, and can constitute a pixel circuit of each of a plurality of pixels. For example, the first transistor T1 can be a driving transistor or a switching transistor of the pixel circuit. The first transistor T1 can include an active layer ACT, a gate electrode G1, a source electrode SE, and a drain electrode DE. The active layer ACT can include a plurality of conductive regions ACT_a and ACT_b and a channel region ACT_c therebetween.

[0068] The light emitting element layer EML can be on the transistor layer TFTL. The light emitting element layer EML can include a first bank NBL1, a light emitting element 30, and a second bank NBL2. The light emitting element 30 can be on the first transistor T1. The light emitting element 30 can be between the first electrode and the second electrode, and can be connected (e.g., coupled) to the first contact electrode and the second contact electrode, respectively.

[0069] Hereinafter, a detailed description will be given of the transistor layer TFTL and the light emitting element layer EML. Figures 3 to 5 Details of the aforementioned transistor layer TFTL and light emitting element layer EML will be described.

[0070] The second planarization layer 41 can be on the light emitting element layer EML to planarize an upper end of the light emitting element layer EML. The second planarization layer 41 can include an organic material. For example, the second planarization layer 41 can include at least one selected from the group consisting of an acrylic resin, an epoxy resin, a phenol resin, a polyamide resin, and a polyimide resin.

[0071] The wavelength conversion layer WLCL can include a first cap layer CAP1, a first light blocking member BK1, a first wavelength conversion portion WLC1, a second wavelength conversion portion WLC2, a light transmitting portion LTU, a second cap layer CAP2, and a third planarization layer 43.

[0072] The first cap layer CAP1 can be on the second planarization layer 41 of the light emitting element layer EML. The first cap layer CAP1 can seal the first wavelength conversion portion WLC1 and the second wavelength conversion portion WLC2, and a lower surface of the light transmitting portion LTU. The first cap layer CAP1 can include an inorganic material. For example, the first cap layer CAP1 can include at least one selected from the group consisting 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.

[0073] The first light blocking member BK1 can be disposed in the first light blocking area BA1, the second light blocking area BA2, and the third light blocking area BA3 on the first cap layer CAP1. The first light blocking member BK1 can overlap the second bank NBL2 in a thickness direction. The first light blocking member BK1 can reduce or block transmission of light. The first light blocking member BK1 can reduce or prevent intrusion of light and color mixing between the first light emitting area LA1, the second light emitting area LA2, and the third light emitting area LA3, thereby improving color reproducibility. In a plan view, the first light blocking member BK1 can have a mesh shape surrounding the first light emitting area LA1, the second light emitting area LA2, and the third light emitting area LA3.

[0074] The first light blocking member BK1 can include an organic light blocking material and a liquid repellent component. Here, the liquid repellent component can be made of a fluorine-containing monomer or a fluorine-containing polymer, and can include, for example, a fluorine-containing aliphatic polycarbonate. For example, the first light blocking member BK1 can be made of a black organic material including the liquid repellent component. The first light blocking member BK1 can be formed by a coating and exposure process of the organic light blocking material including the liquid repellent component.

[0075] Because the first light blocking member BK1 includes the liquid repellent component, the first wavelength conversion portion WLC1 and the second wavelength conversion portion WLC2 and the light transmitting portion LTU can be divided into corresponding light emitting regions LA, for example, a first light emitting region LA1, a second light emitting region LA2, and a third light emitting region LA3. For example, when the first wavelength conversion portion WLC1 and the second wavelength conversion portion WLC2 and the light transmitting portion LTU are formed by an inkjet method, an ink composition can flow on an upper surface of the first light blocking member BK1. In this case, the first light blocking member BK1 includes the liquid repellent component so that the ink composition can flow into each light emitting region. Accordingly, the first light blocking member BK1 can reduce or prevent mixing (e.g., an undesirable mixture) of the ink composition.

[0076] The first wavelength conversion portion WLC1 can be in the first light emitting region LA1 on the first cladding layer CAP1. The first wavelength conversion portion WLC1 can be surrounded by the first light blocking member BK1. The first wavelength conversion portion WLC1 can include a first base resin BS1, a first scatterer SCT1, and a first wavelength shifter WLS1.

[0077] The first base resin BS1 can include a material having a relatively high light transmittance. The first base resin BS1 can be made of a transparent organic material. For example, the first base resin BS1 can include at least one of organic materials such as an epoxy resin, an acrylic resin, a cardo resin, and an imide resin.

[0078] The first scatterer SCT1 can have a refractive index different from that of the first base resin BS1 and can form an optical interface with the first base resin BS1. For example, the first scatterer SCT1 can include a light scattering material and / or a light scattering particle that scatters at least a portion of the transmitted light. For example, the first scatterer SCT1 can include metal oxide particles such as titanium oxide (TiO2) particles, zirconium oxide (ZrO2) particles, aluminum oxide (Al2O3) particles, indium oxide (In2O3) particles, zinc oxide (ZnO) particles, and / or tin oxide (SnO2) particles, or can include organic particles such as acrylic resin particles and / or polyurethane resin particles. The first scatterer SCT1 can scatter light in a random direction without substantially converting the peak wavelength of the incident light regardless of the incident direction of the incident light.

[0079] The first wavelength shifter WLS1 can convert or shift the peak wavelength of the incident light to a first peak wavelength. For example, the first wavelength shifter WLS1 can convert blue light provided from the display apparatus 10 into red light having a unimodal peak wavelength in the range of 610 nm to 650 nm and emit the red light. The first wavelength shifter WLS1 can be a quantum dot, a quantum rod, or a phosphor. The quantum dot can be a particle substance that emits a set or a specific color of light when an electron transitions from a conduction band to a valence band.

[0080] For example, the quantum dot can be a semiconductor nanocrystalline material. The quantum dot can have a specific band gap according to its composition and size, absorb light, and then emit light having a unique wavelength. Examples of the semiconductor nanocrystal of the quantum dot include group IV nanocrystals, group II-VI compound nanocrystals, group III-V compound nanocrystals, group IV-VI compound nanocrystals, and combinations thereof.

[0081] For example, the quantum dot can have a core-shell structure including a core containing the above-described nanocrystal and a shell surrounding the core. The shell of the quantum dot can serve as a protective layer for maintaining the semiconductor property by reducing or preventing chemical modification of the core, and can serve as a charging layer for imparting electrophoretic properties to the quantum dot. The shell can be a single layer or multiple layers. The interface between the core and the shell can have a concentration gradient in which the concentration of elements in the shell decreases toward the center. The shell of the quantum dot can be made of a metal oxide, a non-metal oxide, a semiconductor compound, or a combination thereof.

[0082] The light emitted by the first wavelength shifter WLS1 can have a full width at half maximum (FWHM) of the light emission wavelength spectrum of 45 nm or less, 40 nm or less, or 30 nm or less, and can also improve the color purity and color reproducibility of the colors displayed by the display apparatus 10. The light emitted by the first wavelength shifter WLS1 can be emitted in various directions regardless of the incident direction of the incident light. Thus, the side visibility of the red color displayed in the first light emission area LA1 can be improved.

[0083] A portion of the blue light provided from the light emitting element layer EML can be transmitted through the first wavelength conversion portion WLC1 without being converted to red light by the first wavelength shifter WLS1. Among the blue light provided from the light emitting element layer EML, the light incident on the first color filter CF1 without being converted by the first wavelength conversion portion WLC1 can be blocked by the first color filter CF1. In addition, the red light converted from the blue light provided from the light emitting element layer EML by the first wavelength conversion portion WLC1 can be transmitted through the first color filter CF1 and emitted to the outside.

[0084] The second wavelength conversion portion WLC2 can be in the second light emission area LA2 on the first cladding layer CAP1. The second wavelength conversion portion WLC2 can be surrounded by the first light blocking member BK1. The second wavelength conversion portion WLC2 can include a second base resin BS2, a second scatterer SCT2, and a second wavelength shifter WLS2.

[0085] The second base resin BS2 can include a material having a relatively high light transmittance. The second base resin BS2 can be made of a transparent organic material. For example, the second base resin BS2 can be made of the same material as the first base resin BS1, or can be made of the materials exemplified in the description of the first base resin BS1.

[0086] The second scatterer SCT2 can have a refractive index different from that of the second base resin BS2, and can form an optical interface with the second base resin BS2. For example, the second scatterer SCT2 can include a light scattering material and / or light scattering particles that scatter at least a portion of the transmitted light. For example, the second scatterer SCT2 can be made of the same material as the first scatterer SCT1, or can be made of the materials exemplified in the description of the first scatterer SCT1. Regardless of the incident direction of the incident light, the second scatterer SCT2 can scatter light in random directions without substantially converting the peak wavelength of the incident light.

[0087] The second wavelength shifter WLS2 can convert or shift a peak wavelength of incident light to a second peak wavelength different from the first peak wavelength. For example, the second wavelength shifter WLS2 can convert blue light provided from the display apparatus 10 into green light having a unimodal peak wavelength in the range of 510 nm to 550 nm and emit the green light. The second wavelength shifter WLS2 can be a quantum dot, a quantum rod, or a phosphor. The second wavelength shifter WLS2 can include the same materials as exemplified in the description of the first wavelength shifter WLS1. The second wavelength shifter WLS2 can be made of a quantum dot, a quantum rod, or a phosphor such that a wavelength conversion range of the second wavelength shifter WLS2 is different from a wavelength conversion range of the first wavelength shifter WLS1.

[0088] The light-transmissive portion LTU can be in the third light emitting region LA3 on the first cladding layer CAP1. The light-transmissive portion LTU can be surrounded by the first light blocking member BK1. The light-transmissive portion LTU can transmit incident light by maintaining a peak wavelength of the incident light. The light-transmissive portion LTU can include a third base resin BS3 and a third scatterer SCT3.

[0089] The third base resin BS3 can include a material having a relatively high light transmittance. The third base resin BS3 can be made of a transparent organic material. For example, the third base resin BS3 can be made of the same material as the first base resin BS1 and / or the second base resin BS2, or can be made of a material exemplified in the description of the first base resin BS1 and / or the second base resin BS2.

[0090] The third scatterer SCT3 can have a refractive index different from a refractive index of the third base resin BS3 and can form an optical interface with the third base resin BS3. For example, the third scatterer SCT3 can include a light scattering material and / or light scattering particles that scatter at least a portion of the transmitted light. For example, the third scatterer SCT3 can be made of the same material as the first scatterer SCT1 and / or the second scatterer SCT2, or can be made of a material exemplified in the description of the first scatterer SCT1 and / or the second scatterer SCT2. Regardless of an incident direction of incident light, the third scatterer SCT3 can scatter light in a random direction without substantially converting a peak wavelength of the incident light.

[0091] Because the wavelength conversion layer WLCL is directly on the second planarization layer 41 of the light emitting element layer EML, the display apparatus 10 can not need separate substrates for the first and second wavelength conversion portions WLC1, WLC2 and the light transmitting portion LTU. Accordingly, the first and second wavelength conversion portions WLC1, WLC2 and the light transmitting portion LTU can be easily aligned with each of the first, second, and third light emitting areas LA1, LA2, LA3, and a thickness of the display apparatus 10 can be relatively reduced.

[0092] The second encapsulation layer CAP2 can cover the first and second wavelength conversion portions WLC1, WLC2, the light transmitting portion LTU, and the first light blocking member BK1. For example, the second encapsulation layer CAP2 can seal the first and second wavelength conversion portions WLC1, WLC2 and the light transmitting portion LTU to reduce or prevent damage and / or contamination of the first and second wavelength conversion portions WLC1, WLC2 and the light transmitting portion LTU. The second encapsulation layer CAP2 can be made of the same material as the first encapsulation layer CAP1, or can be made of the materials exemplified in the description of the first encapsulation layer CAP1.

[0093] The third planarization layer 43 can be on the second encapsulation layer CAP2 to planarize upper ends of the first and second wavelength conversion portions WLC1, WLC2 and the light transmitting portion LTU. The third planarization layer 43 can include an organic material. For example, the third planarization layer 43 can include at least one selected from the group consisting of an acrylic resin, an epoxy resin, a phenol resin, a polyamide resin, and a polyimide resin.

[0094] The color filter layer CFL can include the second light blocking member BK2, the first, second, and third color filters CF1, CF2, CF3, and a protective layer PRT.

[0095] The second light blocking member BK2 can be on the third planarization layer 43 of the wavelength conversion layer WLCL in the first, second, and third light blocking areas BA1, BA2, BA3. The second light blocking member BK2 can overlap the first light blocking member BK1 and / or the second bank BNL2 in the thickness direction. The second light blocking member BK2 can reduce or block transmission of light. The second light blocking member BK2 can reduce or prevent intrusion of light and color mixing between the first, second, and third light emitting areas LA1, LA2, LA3, thereby improving color reproducibility. In a plan view, the second light blocking member BK2 can have a mesh shape surrounding the first, second, and third light emitting areas LA1, LA2, LA3.

[0096] The first color filter CF1 can be in the first light emitting area LA1 on the third planarization layer 43. The first color filter CF1 can be surrounded by the second light blocking member BK2. The first color filter CF1 can overlap the first wavelength conversion portion WLC1 in a thickness direction. The first color filter CF1 can selectively transmit light of a first color (e.g., red light), and can block, absorb, or reduce 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 can be a red color filter, and can include a red colorant. The red colorant can be made of a red dye or a red pigment.

[0097] The second color filter CF2 can be in the second light emitting area LA2 on the third planarization layer 43. The second color filter CF2 can be surrounded by the second light blocking member BK2. The second color filter CF2 can overlap the second wavelength conversion portion WLC2 in a thickness direction. The second color filter CF2 can selectively transmit light of a second color (e.g., green light), and can block, absorb, or reduce light of a first color (e.g., red light) and light of a third color (e.g., blue light). For example, the second color filter CF2 can be a green color filter, and can include a green colorant. The green colorant can be made of a green dye or a green pigment.

[0098] The third color filter CF3 can be in the third light emitting area LA3 on the third planarization layer 43. The third color filter CF3 can be surrounded by the second light blocking member BK2. The third color filter CF3 can overlap the light transmissive portion LTU in a thickness direction. The third color filter CF3 can selectively transmit light of a third color (e.g., blue light), and can block, absorb, or reduce 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 can be a blue color filter, and can include a blue colorant. The blue colorant can be made of a blue dye or a blue pigment.

[0099] The first color filter CF1, the second color filter CF2, and the third color filter CF3 can absorb a portion of light incident from the outside of the display apparatus 10 to reduce reflected light caused by external light. Accordingly, the first color filter CF1, the second color filter CF2, and the third color filter CF3 can reduce or prevent color distortion due to reflection of external light.

[0100] The first color filter CF1, the second color filter CF2, and the third color filter CF3 are directly on the third planarization layer 43 of the wavelength conversion layer WLCL, so that the display apparatus 10 can not need separate substrates for the first color filter CF1, the second color filter CF2, and the third color filter CF3. Accordingly, the thickness of the display apparatus 10 can be relatively reduced.

[0101] The protective layer PRT can cover the first color filter CF1, the second color filter CF2, and the third color filter CF3. The protective layer PRT can protect the first color filter CF1, the second color filter CF2, and the third color filter CF3.

[0102] The encapsulation layer TFE can be on the protective layer PRT of the color filter layer CFL. The encapsulation layer TFE can cover the upper surface and the side surface of the display layer. For example, the encapsulation layer TFE can include at least one inorganic layer to reduce or prevent penetration of oxygen and / or moisture. In addition, the encapsulation layer TFE can include at least one organic layer to protect the display apparatus 10 from foreign substances such as dust.

[0103] Hereinafter, the transistor layer TFTL and the light emitting element layer EML will be described in more detail by a planar structure and a cross-sectional structure of one pixel of the display apparatus according to one or more embodiments.

[0104] Figure 3 is a plan view illustrating one pixel of a display apparatus according to one or more embodiments.

[0105] Referring to Figure 3 , each of the plurality of pixels PX can include a plurality of sub-pixels PXn (n is an integer of 1 to 3). For example, one pixel PX can include a first sub-pixel PX1, a second sub-pixel PX2, and a third sub-pixel PX3. The first sub-pixel PX1 can emit light of a first color, the second sub-pixel PX2 can emit light of a second color, and the third sub-pixel PX3 can emit light of a third color. For example, the first color can be blue, the second color can be green, and the third color can be red. However, the present disclosure is not limited thereto, and each sub-pixel PXn can emit light of the same color. Although it is illustrated in Figure 3 that the pixel PX includes three sub-pixels PXn, the present disclosure is not limited thereto, and the pixel PX can include a greater number of sub-pixels PXn.

[0106] Each of the sub-pixels PXn of the display apparatus 10 can include a light emitting area EMA and a non-light emitting area. The light emitting area EMA is defined as an area in which the light emitting element 30 is located to emit light of a set or specific wavelength band, and the non-light emitting area is defined as an area in which the light emitting element 30 is not disposed and light is not emitted. The light emitting area EMA can include an area in which the light emitting element 30 is located, and an area adjacent to the light emitting element 30 to discharge light emitted from the light emitting element 30.

[0107] However, the present disclosure is not limited thereto, and the light emitting area EMA can also include an area in which light emitted from the light emitting element 30 is reflected or refracted by another member and then emitted. A plurality of light emitting elements 30 can be arranged in each of the subpixels PXn, and the light emitting area EMA can be formed by (for example, include) an area in which the plurality of light emitting elements 30 are arranged and an area adjacent to the area.

[0108] Each of the subpixels PXn can include a cutout area CBA in the non-light emitting area. The cutout area CBA can be at one side of the light emitting area EMA in the second direction DR2. The cutout area CBA can be between the light emitting areas EMA of the subpixels PXn adjacent in the second direction DR2. The plurality of light emitting areas EMA and the plurality of cutout areas CBA can be arranged in the display area DPA of the display device 10. For example, the plurality of light emitting areas EMA and the plurality of cutout areas CBA are respectively repeatedly arranged in the first direction DR1, and can be alternately arranged in the second direction DR2. A distance between the cutout areas CBA spaced apart from each other in the first direction DR1 can be smaller than a distance between the light emitting areas EMA spaced apart from each other in the first direction DR1. The second bank BNL2 can be between the cutout areas CBA and the light emitting areas EMA, and a distance therebetween can vary according to a width of the second bank BNL2. Since the light emitting element 30 is not in the cutout area CBA, light is not emitted, but a portion of each of the electrodes 21 and 22 located in each of the subpixels PXn can be in the cutout area CBA. The electrodes 21 and 22 provided for each of the subpixels PXn can be separated from each other in the cutout area CBA.

[0109] Figure 4 is a cross-sectional view taken along lines Q1-Q1', Q2-Q2', and Q3-Q3' of Figure 3 Figure 4 shows a cross-sectional view across both ends of the light emitting element 30 in the first subpixel PX1 of Figure 3

[0110] Referring to Figure 4 and Figure 5 as well as Figure 3 The display device 10 can include a substrate 11, a semiconductor layer on the substrate 11, a plurality of conductive layers, and a plurality of insulating layers. The semiconductor layer, the conductive layer, and the insulating layer can respectively constitute a circuit layer and a light emitting element layer of the display device 10.

[0111] ​​A light-blocking layer BML can be on the substrate 11. The light-blocking layer BML can overlap the active layer ACT of the first transistor T1 of the display device 10. The light-blocking layer BML can include a material that reduces or blocks light, thereby reducing or preventing light from entering the active layer ACT of the first transistor T1. For example, the light-blocking layer BML can be formed of an opaque metal material that reduces or blocks light transmission. However, the present disclosure is not limited thereto, and in some cases, the light-blocking layer BML can be omitted.

[0112] The buffer layer 12 can be entirely on the substrate 11 and the light-blocking layer BML. The buffer layer 12 can be formed on the substrate 11 to protect the first transistor T1 of the pixel PX from moisture penetration through the substrate 11 that is susceptible to moisture penetration, and can perform a surface planarization function. The buffer layer 12 can be formed as a plurality of inorganic layers that are alternately stacked. For example, the buffer layer 12 can be formed as a multilayer structure in which inorganic layers including at least one selected from the group consisting of silicon oxide (SiO x ), silicon nitride (SiN x ), and silicon oxynitride (SiO x N y ) are alternately stacked.

[0113] The semiconductor layer is on the buffer layer 12. The semiconductor layer can include the active layer ACT of the first transistor T1. The semiconductor layer and the buffer layer 12 can partially overlap the gate electrode G1 and the like of the first gate conductive layer, which will be described below.

[0114] Among the transistors included in the sub-pixel PXn of the display device 10, only the first transistor T1 is illustrated in the drawings, but the present disclosure is not limited thereto. The display device 10 can include a larger number of transistors. For example, the display device 10 can include two or three transistors for each sub-pixel PXn, including one or more transistors in addition to the first transistor T1.

[0115] The semiconductor layer can include polycrystalline silicon, single-crystal silicon, and / or an oxide semiconductor. When the semiconductor layer includes an oxide semiconductor, each active layer ACT can include a plurality of conductive regions ACT_a and ACT_b and a channel region ACT_c therebetween. The oxide semiconductor can be an oxide semiconductor containing indium (In). For example, the oxide semiconductor can 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), and / or indium gallium zinc tin oxide (IGZTO).

[0116] In one or more embodiments, the semiconductor layer can include polysilicon. The polysilicon can be formed by crystallizing amorphous silicon, and in this case, the conductive regions ACT_a and ACT_b of the active layer ACT can be doped regions doped with impurities, respectively.

[0117] The first gate insulating layer 13 can be on the semiconductor layer and the buffer layer 12. The first gate insulating layer 13 can cover the semiconductor layer and can be on the buffer layer 12. For example, the first gate insulating layer 13 can be on the buffer layer 12 in addition to the semiconductor layer. The first gate insulating layer 13 can function as a gate insulating layer of each transistor. The first gate insulating layer 13 can be formed of an inorganic layer including an inorganic material such as silicon oxide (SiO x ), silicon nitride (SiN x ), and / or silicon oxynitride (SiO x N y ) or can be formed as a stacked structure of inorganic layers.

[0118] The first gate conductive layer is on the first gate insulating layer 13. The first gate conductive layer can include the gate electrode G1 of the first transistor T1 and the first capacitance electrode CSE1 of the storage capacitor. The gate electrode G1 can overlap the channel region ACT_c of the active layer ACT in a thickness direction. The first capacitance electrode CSE1 can overlap the second capacitance electrode CSE2 (to be described below) in a thickness direction. In one or more embodiments, the first capacitance electrode CSE1 can be integrally connected with (for example, can be integral with) the gate electrode G1. The first capacitance electrode CSE1 can overlap the second capacitance electrode CSE2 in a thickness direction, and the storage capacitor can be formed between the first capacitance electrode CSE1 and the second capacitance electrode CSE2.

[0119] The first gate conductive layer can be formed as a single layer or a plurality of layers including any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu), and an alloy thereof. However, the disclosure is not limited thereto.

[0120] The first interlayer insulating layer 15 is on the first gate conductive layer. The first interlayer insulating layer 15 can function as an insulating layer between the first gate conductive layer and other layers located thereon. The first interlayer insulating layer 15 can cover the first gate conductive layer to perform a function of protecting the first gate conductive layer. The first interlayer insulating layer 15 can be formed of an inorganic layer including an inorganic material such as silicon oxide (SiO x ), silicon nitride (SiN x ), and / or silicon oxynitride (SiO x N y ) or can be formed as a stacked structure of inorganic layers.

[0121] The first data conductive layer is on the first interlayer insulating layer 15. The first data conductive layer can include a source electrode SE and a drain electrode DE of the first transistor T1, a data line DTL, and a second capacitor electrode CSE2.

[0122] The source electrode SE and the drain electrode DE of the first transistor T1 can contact the doped regions ACT_a and ACT_b of the active layer ACT through contact holes that penetrate the first interlayer insulating layer 15 and the first gate insulating layer 13, respectively. In addition, the source electrode SE of the first transistor T1 can be electrically connected (e.g., electrically coupled) to the light-blocking layer BML through another contact hole.

[0123] The data line DTL can apply a data signal to another transistor included in the display device 10. For example, the data line DTL can be connected (e.g., coupled) to a source / drain electrode of another transistor to transmit a signal applied from the data line DTL.

[0124] The second capacitor electrode CSE2 can overlap the first capacitor electrode CSE1 in a thickness direction. In one or more embodiments, the second capacitor electrode CSE2 can be integrally connected (e.g., can be integral) with the source electrode SE.

[0125] The first data conductive layer can be formed to include a single layer or a plurality of layers of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu), and an alloy thereof. However, the present disclosure is not limited thereto.

[0126] The second interlayer insulating layer 17 is on the first data conductive layer. The second interlayer insulating layer 17 can serve as an insulating layer between the first data conductive layer and other layers positioned thereon. The second interlayer insulating layer 17 can cover the first data conductive layer to perform a function of protecting the first data conductive layer. The second interlayer insulating layer 17 can be formed of an inorganic layer including an inorganic material such as silicon oxide (SiO x ), silicon nitride (SiN x ), and / or silicon oxynitride (SiO x N y ), or can be formed as a stacked structure of inorganic layers.

[0127] A second data conductive layer is on the second interlayer insulating layer 17. The second data conductive layer can 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 voltage) supplied to the first transistor T1 can be applied to the first voltage line VL1, and a low potential voltage (or a second power voltage) supplied to the second electrode 22 (which can also be referred to as a "second alignment electrode 22" herein) can be applied to the second voltage line VL2. In a process of manufacturing the display device 10, an alignment signal for aligning the light emitting element 30 can be applied to the second voltage line VL2.

[0128] The first conductive pattern CDP can be connected (e.g., coupled) to the second capacitor electrode CSE2 through a contact hole formed in the second interlayer insulating layer 17. The second capacitor electrode CSE2 can be integrated with (e.g., can be integrally formed with) the source electrode SE of the first transistor T1, and the first conductive pattern CDP can be electrically connected (e.g., electrically coupled) to the source electrode SE. The first conductive pattern CDP can also be in contact with the first electrode 21 to be described below, and the first transistor T1 can transmit the first power voltage applied from the first voltage line VL1 to the first electrode 21 through the first conductive pattern CDP. Although the second data conductive layer is shown to include one second voltage line VL2 and one first voltage line VL1 in the drawings, the present disclosure is not limited thereto. The second data conductive layer can include a greater number of first voltage lines VL1 and / or a greater number of second voltage lines VL2.

[0129] The second data conductive layer can be formed to include a single layer or a plurality of layers of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu), and alloys thereof. However, the present disclosure is not limited thereto.

[0130] A first planarization layer 19 is on the second data conductive layer. The first planarization layer 19 can include an organic insulating material, such as an organic material such as polyimide (PI), and can perform a surface planarization function.

[0131] A plurality of first banks BNL1, a plurality of electrodes 21 and 22, the light emitting element 30, a plurality of contact electrodes CNE1 and CNE2, and a second bank BNL2 can be disposed on the first planarization layer 19. In addition, a plurality of insulating layers PAS1, PAS2, PAS3, and PAS4 can be disposed on the first planarization layer 19.

[0132] The plurality of first banks BNL1 can be directly disposed on the first planarization layer 19. The plurality of first banks BNL1 has a shape extending in the second direction DR2 within each sub-pixel PXn, but can not extend to another adjacent sub-pixel PXn in the second direction DR2, and can be disposed in the light emitting area EMA. In one or more embodiments, the plurality of first banks BNL1 is disposed to be spaced apart from each other in the first direction DR1, and the light emitting element 30 can be located therebetween. The plurality of first banks BNL1 can be provided for each sub-pixel PXn to form a linear pattern in the display area DPA of the display device 10. In the drawings, two first banks BNL1 are shown, but the present disclosure is not limited thereto. A greater number of first banks BNL1 can be provided, depending on the number of electrodes 21 and 22.

[0133] The first bank BNL1 can have a structure in which at least a portion thereof protrudes from an upper surface of the first planarization layer 19. The protruding portion of the first bank BNL1 can have an inclined side surface, and light emitted from the light emitting element 30 can be reflected from the electrodes 21 and 22 located on the first bank BNL1 and emitted in an upward direction (e.g., away from the first planarization layer 19) of the first planarization layer 19. The first bank BNL1 can provide an area in which the light emitting element 30 is located, and at the same time, can serve as a reflection barrier that reflects light emitted from the light emitting element 30 in the upward direction. The side surface of the first bank BNL1 can be inclined in a linear shape, but is not limited thereto, and in some embodiments, the outer surface of the first bank BNL1 can have a curved semi-circular or semi-elliptical shape. The first bank BNL1 can include an organic insulating material such as polyimide (PI), but the material thereof is not limited thereto.

[0134] The plurality of electrodes 21 and 22 is disposed on the first bank BNL1 and the first planarization layer 19. The plurality of electrodes 21 and 22 can include the first electrode 21 and the second electrode 22. The first electrode 21 and the second electrode 22 can extend in the second direction DR2, and can be spaced apart from each other in the first direction DR1.

[0135] Each of the first and second electrodes 21 and 22 can extend in the second direction DR2 within the sub-pixel PXn and can be separated from the other electrodes 21 and 22 in the cutaway region CBA. For example, the cutaway region CBA can be between the light emitting regions EMA of the sub-pixels PXn adjacent in the second direction DR2, and the first and second electrodes 21 and 22 can be separated from the other first and second electrodes 21 and 22 in the sub-pixels PXn adjacent in the second direction DR2 in the cutaway region CBA. However, the present disclosure is not limited thereto, and some of the electrodes 21 and 22 can extend beyond the sub-pixels PXn adjacent in the second direction DR2, instead of being separated from each other for each sub-pixel PXn, or only one of the first and second electrodes 21 and 22 can be separated.

[0136] The first electrode 21 can be electrically connected (e.g., electrically coupled) to the first transistor T1 through the first contact hole CT1, and the second electrode 22 can be electrically connected (e.g., electrically coupled) to the second voltage line VL2 through the second contact hole CT2. For example, the first electrode 21 can be in contact with the first conductive pattern CDP through the first contact hole CT1 that penetrates the first planarization layer 19 in the portion of the second bank BNL2 extending in the first direction DR1. The second electrode 22 can also be in contact with the second voltage line VL2 through the second contact hole CT2 that penetrates the first planarization layer 19 in the portion of the second bank BNL2 extending in the first direction DR1. However, the present disclosure is not limited thereto. In one or more other embodiments, the first and second contact holes CT1 and CT2 can be within the light emitting region EMA surrounded by the second bank BNL2 so as not to overlap the second bank BNL2.

[0137] Although it is shown in the drawings that one first electrode 21 and one second electrode 22 are provided for each sub-pixel PXn, the present disclosure is not limited thereto, and the number of the first and second electrodes 21 and 22 for each sub-pixel PXn can be greater. The first and second electrodes 21 and 22 in each sub-pixel PXn can not necessarily have a shape extending in one direction, and the first and second electrodes 21 and 22 can have various suitable structures. For example, the first and second electrodes 21 and 22 can have a partially curved and / or bent shape, and one electrode can be arranged to surround the other electrode.

[0138] Each of the first and second electrodes 21 and 22 can be directly on the first bank BNL1. Each of the first and second electrodes 21 and 22 can be formed to have a larger width than the first bank BNL1. For example, each of the first and second electrodes 21 and 22 can cover the outer surface of the first bank BNL1. Each of the first and second electrodes 21 and 22 can be on the upper surface and the side surface of the first bank BNL1, and the pitch between the first and second electrodes 21 and 22 can be narrower than the pitch between the first banks BNL1. At least a portion of the first electrode 21 and at least a portion of the second electrode 22 are directly on the first planarization layer 19, so that the first and second electrodes 21 and 22 can be on the same plane. However, the present disclosure is not limited thereto. In some embodiments, each of the electrodes 21 and 22 can have a smaller width than the width of the first bank BNL1. However, each of the electrodes 21 and 22 can cover at least one side surface of the first bank BNL1 to reflect light emitted from the light emitting element 30.

[0139] Each of the electrodes 21 and 22 can include a conductive material having high reflectivity. For example, each of the first and second electrodes 21 and 22 (which can also be referred to herein as "alignment electrodes 21 and 22") can include a metal such as silver (Ag), copper (Cu), and / or aluminum (Al) as a conductive material having high reflectivity, or can include an alloy containing aluminum (Al), nickel (Ni), and / or lanthanum (La). Each of the electrodes 21 and 22 can reflect light emitted from the light emitting element 30 and advancing to the side surface of the first bank BNL1 in the upward direction of each sub-pixel PXn.

[0140] However, the present disclosure is not limited thereto, and each of the electrodes 21 and 22 can also include a transparent conductive material. For example, each of the electrodes 21 and 22 can include a material such as indium tin oxide (ITO), indium zinc oxide (IZO), and / or indium tin zinc oxide (ITZO). In some embodiments, each of the electrodes 21 and 22 can have a structure in which one or more layers of a transparent conductive material and one or more layers of a metal having high reflectivity are stacked, or can be formed to include one layer of a transparent conductive material and a metal. For example, each of the electrodes 21 and 22 can have a stacked structure of ITO / Ag / ITO, ITO / Ag / IZO, or ITO / Ag / ITZO / IZO.

[0141] The plurality of electrodes 21 and 22 can be electrically connected (e.g., electrically coupled) to the light emitting element 30, and a set or predetermined voltage can be applied to the electrodes 21 and 22 so that the light emitting element 30 emits light. The plurality of alignment electrodes 21 and 22 can be electrically connected (e.g., electrically coupled) to the light emitting element 30 through the contact electrodes CNE1 and CNE2, and an electrical signal applied to the electrodes 21 and 22 can be transmitted to the light emitting element 30 through the contact electrodes CNE1 and CNE2.

[0142] One of the first electrode 21 and the second electrode 22 can be electrically connected (e.g., electrically coupled) to an anode electrode of the light emitting element 30, and the other thereof can be electrically connected (e.g., electrically coupled) to a cathode electrode of the light emitting element 30. However, the disclosure is not limited thereto, and one of the first electrode 21 and the second electrode 22 can be electrically connected (e.g., electrically coupled) to a cathode electrode of the light emitting element 30, and the other thereof can be electrically connected (e.g., electrically coupled) to an anode electrode of the light emitting element 30.

[0143] Each of the electrodes 21 and 22 can be used (e.g., utilized) to form an electric field in the sub-pixel PXn to align the light emitting element 30. The light emitting element 30 can be positioned between the first electrode 21 and the second electrode 22 by the electric field formed on the first electrode 21 and the second electrode 22. The light emitting element 30 of the display device 10 can be jetted onto the electrodes 21 and 22 by an inkjet printing process. When the ink including the light emitting element 30 is jetted onto the electrodes 21 and 22, an alignment signal is applied to the electrodes 21 and 22 to form an electric field. The light emitting element 30 dispersed in the ink can be aligned on the electrodes 21 and 22 by receiving an electrophoretic force from the electric field formed on the electrodes 21 and 22.

[0144] The first insulating layer PAS1 is on the first planarization layer 19. The first insulating layer PAS1 can cover the first bank BNL1, the first electrode 21, and the second electrode 22. The first insulating layer PAS1 can protect the first electrode 21 and the second electrode 22 and insulate them from each other. In addition, the first insulating layer PAS1 can reduce or prevent the light emitting element 30 thereon from being damaged due to direct contact with other members.

[0145] In one or more embodiments, the first insulating layer PAS1 can include openings OP partially exposing the first electrode 21 and the second electrode 22. Each of the openings OP can partially expose a portion of the electrodes 21 and 22 on the upper surface of the first bank BNL1. Portions of the contact electrodes CNE1 and CNE2 can be in contact with the electrodes 21 and 22, respectively, exposed through the openings OP.

[0146] The first insulating layer PAS1 can have a step formed between the first electrode 21 and the second electrode 22, so that a portion of the upper surface of the first insulating layer PAS1 is recessed. For example, when the first insulating layer PAS1 is provided so as to cover the first electrode 21 and the second electrode 22, the upper surface of the first insulating layer PAS1 can be stepped according to the shape of the electrodes 21 and 22 below the first insulating layer PAS1. However, the present disclosure is not limited thereto.

[0147] The second bank BNL2 can be on the first insulating layer PAS1. The second bank BNL2 can be arranged in a grid pattern across the display area DPA, including portions extending in the first direction DR1 and the second direction DR2 in a plan view. The second bank BNL2 can be positioned across the boundary of each sub-pixel PXn to distinguish adjacent sub-pixels PXn.

[0148] The second bank BNL2 can surround the light emitting area EMA and the cut area CBA for each sub-pixel PXn to distinguish them. The first electrode 21 and the second electrode 22 can extend in the second direction DR2 and can be positioned across a portion of the second bank BNL2 in the first direction DR1. In the portion of the second bank BNL2 extending in the second direction DR2, the portion between the light emitting areas EMA can have a greater width than the portion between the cut areas CBA. Accordingly, the pitch between the cut areas CBA can be less than the pitch between the light emitting areas EMA.

[0149] The second bank BNL2 can be formed to have a greater height than the height of the first bank BNL1. In an inkjet printing process of a process of manufacturing the display apparatus 10, the second bank BNL2 can reduce or prevent ink from overflowing to an adjacent sub-pixel PXn, thereby separating inks in which different light emitting elements 30 are dispersed so that the inks do not mix with each other. Like the first bank BNL1, the second bank BNL2 can include polyimide (PI), but the material thereof is not limited thereto.

[0150] The light emitting element 30 can be on the first insulating layer PAS1. The plurality of light emitting elements 30 are arranged to be spaced apart from each other along the second direction DR2 in which the electrodes 21 and 22 extend, and can be aligned substantially in parallel to each other. The light emitting element 30 can have a shape extending in one direction, and the direction in which the electrodes 21 and 22 extend can be substantially perpendicular to the direction in which the light emitting element 30 extends. However, the present disclosure is not limited thereto, and the light emitting element 30 can be positioned obliquely in the direction in which the electrodes 21 and 22 extend, rather than being perpendicular to the direction in which the electrodes 21 and 22 extend.

[0151] The light emitting element 30 in each sub-pixel PXn can include a light emitting layer (e.g., a light emitting layer including a different material) including a different material from the light emitting layer of the light emitting element 30 in the adjacent sub-pixel PXn. Figure 5The light emitting element 30 can be configured to emit light of different wavelengths (e.g., different colors) from the same light emitting element 30. For example, the light emitting element 30 can include a first light emitting element 30a, a second light emitting element 30b, and a third light emitting element 30c (e.g., elements "31", "32", and "33" in FIG. 1). The first light emitting element 30a can be configured to emit light of a first color (e.g., red light), the second light emitting element 30b can be configured to emit light of a second color (e.g., green light), and the third light emitting element 30c can be configured to emit light of a third color (e.g., blue light). The light emitting element 30 can be configured to emit light of different colors (e.g., different colors of light) from different sub-pixels PXn (e.g., elements "36" in FIG. 1). Thus, light of a first color, light of a second color, and light of a third color can be emitted from the first sub-pixel PX1, the second sub-pixel PX2, and the third sub-pixel PX3, respectively. However, the present disclosure is not limited thereto, and each of the sub-pixels PXn can include the same type (or kind) of light emitting element 30 to emit substantially the same color of light.

[0152] The two ends of the light emitting element 30 can be on the electrodes 21 and 22 between the first bank portions BNL1. The light emitting element 30 can have a length that is longer than the spacing between the first electrode 21 and the second electrode 22, and the two ends of the light emitting element 30 can be on the first electrode 21 and the second electrode 22, respectively. For example, one end of the light emitting element 30 can be placed on the first electrode 21, and the other end thereof can be placed on the second electrode 22.

[0153] The light emitting element 30 can be provided with a plurality of layers in a direction perpendicular (e.g., substantially perpendicular) to the upper surface of the substrate 11 or the first planarization layer 19. The light emitting element 30 can be positioned such that one extension direction is parallel to the upper surface of the first planarization layer 19, and a plurality of semiconductor layers included in the light emitting element 30 can be arranged in order along a direction parallel to the upper surface of the first planarization layer 19. However, the present disclosure is not limited thereto. When the light emitting element 30 has a different structure, a plurality of semiconductor layers can be arranged in a direction perpendicular (e.g., substantially perpendicular) to the first planarization layer 19.

[0154] The two ends of the light emitting element 30 can contact the contact electrodes CNE1 and CNE2, respectively. For example, the light emitting element 30 can not be provided with an insulating film (e.g., element "38" in FIG. 1) on the end surfaces in one direction, and a portion of a semiconductor layer (e.g., elements "31" and / or "32" in FIG. 1) and an electrode layer (e.g., element "37" in FIG. 1) included in the light emitting element 30 can be exposed. Thus, the exposed semiconductor layer (e.g., elements "31" and / or "32" in FIG. 1) and the electrode layer (e.g., element "37" in FIG. 1) can directly contact the contact electrodes CNE1 and CNE2. Figure 5 Figure 5 A portion of a semiconductor layer (e.g., elements "31" and / or "32" in FIG. 1) and an electrode layer (e.g., element "37" in FIG. 1) included in the light emitting element 30 can be exposed, and thus, the exposed semiconductor layer (e.g., elements "31" and / or "32" in FIG. 1) and the electrode layer (e.g., element "37" in FIG. 1) can contact the contact electrodes CNE1 and CNE2. However, the present disclosure is not limited thereto. In the light emitting element 30, at least a portion of the insulating film 38 can be removed such that two side surfaces of the semiconductor layer (e.g., elements "31", "32", and / or "37" in FIG. 1) and the electrode layer (e.g., element "37" in FIG. 1) can be partially exposed. Figure 5 Figure 5 A portion of a semiconductor layer (e.g., elements "31" and / or "32" in FIG. 1) and an electrode layer (e.g., element "37" in FIG. 1) included in the light emitting element 30 can be exposed, and thus, the exposed semiconductor layer (e.g., elements "31" and / or "32" in FIG. 1) and the electrode layer (e.g., element "37" in FIG. 1) can contact the contact electrodes CNE1 and CNE2. However, the present disclosure is not limited thereto. In the light emitting element 30, at least a portion of the insulating film 38 can be removed such that two side surfaces of the semiconductor layer (e.g., elements "31", "32", and / or "37" in FIG. 1) and the electrode layer (e.g., element "37" in FIG. 1) can be partially exposed. Figure 5 Figure 5 A portion of a semiconductor layer (e.g., elements "31" and / or "32" in FIG. 1) and an electrode layer (e.g., element "37" in FIG. 1) included in the light emitting element 30 can be exposed, and thus, the exposed semiconductor layer (e.g., elements "31" and / or "32" in FIG. 1) and the electrode layer (e.g., element "37" in FIG. 1) can contact the contact electrodes CNE1 and CNE2. However, the present disclosure is not limited thereto. In the light emitting element 30, at least a portion of the insulating film 38 can be removed such that two side surfaces of the semiconductor layer (e.g., elements "31", "32", and / or "37" in FIG. 1) and the electrode layer (e.g., element "37" in FIG. 1) can be partially exposed. Figure 5

[0155] ​​​​The second insulating layer PAS2 can be partially on the light emitting element 30. For example, the second insulating layer PAS2 can be on the light emitting element 30 to have a width (e.g., in the first direction DR1) that is smaller than a length of the light emitting element 30, such that the second insulating layer PAS2 exposes both ends of the light emitting element 30 while surrounding the light emitting element 30. The second insulating layer PAS2 can cover the light emitting element 30, the electrodes 21 and 22, and the first insulating layer PAS1 during a process of manufacturing the display apparatus 10, and then can be removed to expose both ends of the light emitting element 30. In a plan view, the second insulating layer PAS2 can be on the first insulating layer PAS1 to extend in the second direction DR2, thereby forming a linear or island-like pattern in each sub-pixel PXn. In the process of manufacturing the display apparatus 10, the second insulating layer PAS2 can protect the light emitting element 30 and fix the light emitting element 30.

[0156] The plurality of contact electrodes CNE1 and CNE2 and the third insulating layer PAS3 can be on the second insulating layer PAS2.

[0157] The plurality of contact electrodes CNE1 and CNE2 can have a shape extending in one direction, and can be on each of the electrodes 21 and 22, respectively. The contact electrodes CNE1 and CNE2 can include a first contact electrode CNE1 on the first electrode 21 and a second contact electrode CNE2 on the second electrode 22. The contact electrodes CNE1 and CNE2 can be spaced apart from each other and can face each other. For example, the first contact electrode CNE1 and the second contact electrode CNE2 can be on the first electrode 21 and the second electrode 22, respectively, and can be spaced apart from each other in the first direction DR1. Each of the contact electrodes CNE1 and CNE2 can form a stripe pattern in the light emitting area EMA of each sub-pixel PXn.

[0158] Each of the plurality of contact electrodes CNE1 and CNE2 can contact the 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. In the light emitting element 30, a semiconductor layer is exposed on both end surfaces in an extension direction of the light emitting element 30, and the contact electrodes CNE1 and CNE2 can be in electrical contact with the semiconductor layer and the electrode layer of the light emitting element 30. One side of each of the contact electrodes CNE1 and CNE2 contacting both ends of the light emitting element 30 can be on the second insulating layer PAS2. The first contact electrode CNE1 can contact the first electrode 21 (which can also be referred to as a "first alignment electrode 21" herein) through an opening OP exposing a portion of an upper surface of the first electrode 21, and the second contact electrode CNE2 can contact the second electrode 22 through an opening OP exposing a portion of an upper surface of the second electrode 22.

[0159] A width of each of the contact electrodes CNE1 and CNE2 measured in one direction (e.g., in the first direction DR1) can be smaller than a width of each of the electrodes 21 and 22 measured in one direction. Each of the contact electrodes CNE1 and CNE2 can contact one end and the other end of the light emitting element 30 and cover a portion of the upper surface of each of the first electrode 21 and the second electrode 22. However, the disclosure is not limited thereto, and the contact electrodes CNE1 and CNE2 can be formed to have a larger width than the electrodes 21 and 22 to cover both sides of the electrodes 21 and 22.

[0160] The contact electrodes CNE1 and CNE2 can each independently include a transparent conductive material. For example, the contact electrodes CNE1 and CNE2 can include ITO, IZO, ITZO, and / or aluminum (Al). Light emitted from the light emitting element 30 can pass through the contact electrodes CNE1 and CNE2 and advance toward the electrodes 21 and 22. However, the disclosure is not limited thereto.

[0161] Although two contact electrodes CNE1 and CNE2 are shown in one sub-pixel PXn in the drawings, the disclosure is not limited thereto. The number of the contact electrodes CNE1 and CNE2 can vary according to the number of the electrodes 21 and 22 used for each sub-pixel PXn.

[0162] The third insulating layer PAS3 can cover the first contact electrode CNE1. For example, the third insulating layer PAS3 can cover the first contact electrode CNE1 such that the third insulating layer PAS3 covers a side on which the first contact electrode CNE1 is located based on (e.g., with respect to) the second insulating layer PAS2. The third insulating layer PAS3 can cover a side on which the first contact electrode CNE1 is located based on (e.g., with respect to) the second insulating layer PAS2, in addition to the first contact electrode CNE1. For example, the third insulating layer PAS3 can cover the first contact electrode CNE1 and the first electrode 21. Such an arrangement can be formed by a process of partially removing an insulating material layer that will form the third insulating layer PAS3 after the insulating material layer is completely placed in the light emitting area EMA to form the second contact electrode CNE2. In the above process, the insulating material layer that forms the third insulating layer PAS3 can be removed together with the insulating material layer that forms the second insulating layer PAS2, and a side of the third insulating layer PAS3 can be aligned with a side of the second insulating layer PAS2. A side of the second contact electrode CNE2 can be on the third insulating layer PAS3, and the second contact electrode CNE2 can be insulated from the first contact electrode CNE1, and the third insulating layer PAS3 between the first contact electrode CNE1 and the first contact electrode CNE1.

[0163] The fourth insulating layer PAS4 can be entirely in the display area DPA of the substrate 11. The fourth insulating layer PAS4 can function to protect components on the substrate 11 from an external environment. However, in some embodiments, the fourth insulating layer PAS4 can be omitted.

[0164] Each of the first insulating layer PAS1, the second insulating layer PAS2, the third insulating layer PAS3, and the fourth insulating layer PAS4 described above can include an inorganic insulating material or an organic insulating material. For example, each of the first insulating layer PAS1, the second insulating layer PAS2, the third insulating layer PAS3, and the fourth insulating layer PAS4 can include an inorganic insulating material such as silicon oxide (SiO x ), silicon nitride (SiN x ), silicon oxynitride (SiO x N y ), aluminum oxide (Al2O3), and / or aluminum nitride (AlN). In one or more embodiments, each of the first insulating layer PAS1, the second insulating layer PAS2, the third insulating layer PAS3, and the fourth insulating layer PAS4 can include an organic insulating layer such as an acrylic resin, an epoxy resin, a phenol resin, a polyamide resin, a polyimide resin, an unsaturated polyester resin, a polyphenylene resin, a polyphenylene sulfide resin, a benzocyclobutene, a cardo resin, a siloxane resin, a silsesquioxane resin, a polymethyl methacrylate, a polycarbonate, and / or a polymethyl methacrylate-polycarbonate synthetic resin. However, the present disclosure is not limited thereto.

[0165] Figure 5 is a schematic view of a light emitting element according to one or more embodiments.

[0166] Referring to Figure 5 , the light emitting element 30 is a particulate element (e.g., can be formed as a particle), and can have a rod or cylindrical shape having a set or predetermined aspect ratio. The light emitting element 30 can have a size in a nanometer scale (the nanometer scale can be from 1 nm or more to less than 1 µm) or a micrometer scale (the micrometer scale can be from 1 µm or more to less than 1 mm). In one or more embodiments, the light emitting element 30 can have a size in which both the diameter and the length are in a nanometer scale, or can have a size in which both the diameter and the length are in a micrometer scale. In some embodiments, the light emitting element 30 can have a size in which the diameter is in a nanometer scale, whereas the length can be in a micrometer scale. In some embodiments, some light emitting elements 30 can have a size in which the diameter and / or the length are in a nanometer scale, whereas other light emitting elements 30 can have a size in which the diameter and / or the length are in a micrometer scale.

[0167] In one or more embodiments, the light-emitting element 30 may be an inorganic light-emitting diode. For example, the light-emitting element 30 may include a semiconductor layer doped with impurities of any conductivity type (e.g., p-type or n-type). The semiconductor layer may receive electrical signals applied from an external power source and may emit light of a set or specific wavelength band.

[0168] The light-emitting element 30 according to one or more embodiments may include a first semiconductor layer 31, a light-emitting layer 36, a second semiconductor layer 32, and an electrode layer 37 stacked sequentially. The light-emitting element 30 may also include an insulating film 38 surrounding the outer surfaces of the first semiconductor layer 31, the second semiconductor layer 32, and the light-emitting layer 36.

[0169] The first semiconductor layer 31 may be an n-type semiconductor layer. When the light-emitting element 30 emits (or is to emit) light in the blue wavelength band, the first semiconductor layer 31 may include an Al-type semiconductor layer. x Ga y In 1-x-y The semiconductor material has the chemical formula N (0≤x≤1, 0≤y≤1, 0≤x+y≤1). For example, the semiconductor material can be at least one selected from the group consisting of AlGaInN, GaN, AlGaN, GaInN, AlN, and InN, each doped with an n-type impurity. The first semiconductor layer 31 can be doped with an n-type dopant. The n-type dopant can be Si, Ge, Se, and / or Sn. For example, the first semiconductor layer 31 can be n-GaN doped with n-type Si. The length of the first semiconductor layer 31 can be in the range of about 1.5 μm to about 5 μm, but is not limited thereto.

[0170] The second semiconductor layer 32 is located on the light-emitting layer 36, which will be described below. The second semiconductor layer 32 may be a p-type semiconductor layer. When the light-emitting element 30 emits (or is to emit) light in the blue or green wavelength band, the second semiconductor layer 32 may include a p-type semiconductor layer. x Ga y In 1-x-y The semiconductor material has the chemical formula N (0≤x≤1, 0≤y≤10, 0≤x+y≤1). For example, the semiconductor material can be at least one selected from the group consisting of AlGaInN, GaN, AlGaN, GaInN, AlN, and InN, each doped with a p-type impurity. The second semiconductor layer 32 can be doped with a p-type dopant. The p-type dopant can be Mg, Zn, Ca, and / or Ba. For example, the second semiconductor layer 32 can be p-GaN doped with p-type Mg. The length of the second semiconductor layer 32 can be in the range of about 0.05 μm to about 0.10 μm, but is not limited thereto.

[0171] Despite Figure 5Each of the first semiconductor layer 31 and the second semiconductor layer 32 is shown as being formed as one layer in FIG. 1, but the present disclosure is not limited thereto. Each of the first semiconductor layer 31 and the second semiconductor layer 32 can also include a greater number of layers, such as a cladding layer and / or a tensile-strained barrier-reduction (TSBR) layer, depending on the material of the light-emitting layer 36.

[0172] The light-emitting layer 36 can be between the first semiconductor layer 31 and the second semiconductor layer 32. The light-emitting layer 36 can include a material of a single quantum well structure or a multi-quantum well structure. When the light-emitting layer 36 includes a material of a multi-quantum well structure, the light-emitting layer 36 can have a structure in which quantum layers and well layers are alternately stacked. The light-emitting layer 36 can emit light by recombination of electron-hole pairs according to an electrical signal applied through the first semiconductor layer 31 and the second semiconductor layer 32. When the light-emitting layer 36 emits (or is to emit) light of a blue wavelength band, the light-emitting layer 36 can include a material such as AlGaN and / or AlGaInN. For example, when the light-emitting layer 36 has a multi-quantum well structure in which quantum layers and well layers are alternately stacked, the quantum well can include a material such as AlGaN and / or AlGaInN, and the well layer can include a material such as GaN and / or AlInN. For example, the light-emitting layer 36 includes quantum wells each containing AlGaInN, and well layers each containing AlInN, and thus the light-emitting layer 36 can emit blue light having a central wavelength band of about 450 nm to about 495 nm as described above.

[0173] However, the present disclosure is not limited thereto, and the light-emitting layer 36 can have a structure in which a semiconductor material having a high band gap energy and a semiconductor material having a low band gap energy are alternately stacked, and can include other group III to group V semiconductor materials according to a wavelength band of light. The light emitted from the light-emitting layer 36 is not limited to light of a blue wavelength band, and in some embodiments, the light-emitting layer 36 can emit light of a red or green wavelength band. The length of the light-emitting layer 36 can be in a range of about 0.05 μm to about 0.10 μm, but is not limited thereto.

[0174] In one or more embodiments, the light emitted from the light-emitting layer 36 can be emitted to both side surfaces of the light-emitting element 30 and a longitudinal outer surface of the light-emitting element 30. The direction of the light emitted from the light-emitting layer 36 is not limited to one direction.

[0175] The electrode layer 37 can be an ohmic contact electrode. However, the present disclosure is not limited thereto, and the electrode layer 37 can be a Schottky contact electrode. The light-emitting element 30 can include at least one electrode layer 37. Although in the embodiment shown in FIG. 1 the light-emitting element 30 includes two electrode layers 37, the present disclosure is not limited thereto. Figure 5The image shows a light-emitting element 30 including an electrode layer 37, but this disclosure is not limited thereto. In some embodiments, the light-emitting element 30 may include a larger number of electrode layers 37, or the electrode layers 37 may be omitted. The description of the light-emitting element 30, which will be described below, can be applied in the same way, even if the number of electrode layers 37 is changed or the light-emitting element 30 includes other structures.

[0176] When the light-emitting element 30 is electrically connected (e.g., electrically coupled) to an electrode or contact electrode in the display device 10 according to one or more embodiments, the electrode layer 37 can reduce the resistance between the light-emitting element 30 and the electrode or contact electrode. The electrode layer 37 may include a conductive metal. For example, the electrode layer 37 may include at least one selected from the group consisting of aluminum (Al), titanium (Ti), indium (In), gold (Au), silver (Ag), indium tin oxide (ITO), indium zinc oxide (IZO), and indium tin zinc oxide (ITZO). The electrode layer 37 may include a semiconductor material doped with n-type or p-type impurities. The electrode layer 37 may include the same material and may include different materials, but this disclosure is not limited thereto.

[0177] The insulating film 38 may surround the outer surfaces of the aforementioned semiconductor layers (e.g., the first semiconductor layer 31 and the second semiconductor layer 32) and electrode layers (e.g., electrode layer 37). For example, the insulating film 38 may at least surround the outer surface of the light-emitting layer 36 and may extend in one direction in which the light-emitting element 30 extends. The insulating film 38 may serve to protect the component. For example, the insulating film 38 may be formed to surround the side surfaces of the component and may be formed such that both ends of the light-emitting element 30 are exposed in its length direction (e.g., the extension direction).

[0178] Despite Figure 5 The diagram shows that the insulating film 38 can extend along the length of the light-emitting element 30 to cover the side surfaces from the first semiconductor layer 31 to the electrode layer 37, but this disclosure is not limited thereto. The insulating film 38 may cover only a portion of the semiconductor layer and the outer surface of the light-emitting layer 36, or only a portion of the outer surface of the electrode layer 37 to partially expose the outer surface of the electrode layer 37. The insulating film 38 may be formed to have a circular cross-section in a region adjacent to at least one end of the light-emitting element 30.

[0179] The thickness of the insulating film 38 can be in the range of about 10 nm to about 1.0 μm, but is not limited thereto. For example, the thickness of the insulating film 38 can be about 40 nm.

[0180] The insulating film 38 may include a material with insulating properties, such as silicon oxide (SiO2). x ), silicon nitride (SiN) x ), silicon oxynitride (SiO) x Ny ), aluminum nitride (AIN), and / or aluminum oxide (AI2O3). Thus, the light emitting layer 36 can reduce or prevent an electrical short (e.g., an electrical short circuit) that can occur when the light emitting layer 36 is in direct contact with an electrode through which an electrical signal is transmitted to the light emitting element 30. In addition, because the insulating film 38 protects the light emitting layer 36 as well as the outer surface of the light emitting element 30, degradation of the light emitting efficiency can be reduced or prevented.

[0181] In one or more embodiments, the outer surface of the insulating film 38 can be surface treated. The light emitting element 30 can be aligned by being jetted onto the electrodes (e.g., the electrodes 21 and 22) in a state in which they are dispersed in a set or predetermined ink. Here, the surface of the insulating film 38 can be hydrophobically or hydrophilically treated in order to maintain the light emitting element 30 in a dispersed state without being aggregated with other adjacent light emitting elements 30 in the ink. For example, the outer surface of the insulating film 38 can be surface treated with a material such as stearic acid and / or 2,3-naphthalene dicarboxylic acid.

[0182] In the above-described display device 10, the first wavelength converting portion WLC1, the second wavelength converting portion WLC2, and the light transmitting portion LTU can be formed by jetting a set or predetermined ink onto the substrate 11 during a process of manufacturing the display device 10, in which the scatterers SCT1, SCT2, and SCT3 are dispersed in the base resins BS1, BS2, and BS3, respectively, in the set or predetermined ink. In addition, the light emitting element 30 of the display device 10 can also be jetted onto the substrate 11 in a state in which it is dispersed in the set or predetermined ink, and can be aligned.

[0183] The above-described scatterers SCT1, SCT2, and SCT3 and the light emitting element 30 can be formed as fine particles that can be dispersed in an ink, and the ink can be jetted onto the substrate 11. After the ink is supplied through an inlet of a print head unit and dispersed through a nozzle, the remaining ink is circulated through an outlet of the print head unit. However, because an area adjacent to the outlet of the print head unit can have a reduced flow rate compared to an area adjacent to the inlet of the print head unit, the fine particles can settle in the area adjacent to the outlet, such that the number of fine particles in the ink jetted through the nozzle can be reduced.

[0184] Hereinafter, an inkjet printing apparatus for reducing or preventing the settlement of particles remaining in a print head unit and making the number of particles in an ink uniform (or substantially uniform) will be described.

[0185] Figure 6 is a schematic plan view of an inkjet printing apparatus according to one or more embodiments. Figure 7 is a schematic bottom view of a print head unit according to one or more embodiments. Figure 8is a schematic diagram illustrating an operation of a print head unit according to one or more embodiments. Figure 9 is a schematic diagram illustrating a print head unit according to one or more embodiments.

[0186] Reference Figures 6 to 9 An inkjet printing apparatus 1000 according to one or more embodiments includes a print head unit 100 having a plurality of inkjet heads 300. The inkjet printing apparatus 1000 can further include a stage STA, an ink circulation unit 500, and a base frame 600.

[0187] The inkjet printing apparatus 1000 can use the print head unit 100 to eject a set or predetermined ink 90 onto a target substrate SUB. The target substrate SUB can be disposed on the stage STA.

[0188] The stage STA can provide an area in which the target substrate SUB is placed. The inkjet printing apparatus 1000 includes a first rail RL1 and a second rail RL2 extending in a second direction DR2, and the stage STA is placed on the first rail RL1 and the second rail RL2. The stage STA can be moved on the first rail RL1 and the second rail RL2 in the second direction DR2 by a separate moving member. The stage STA can be moved in the second direction DR2, and the ink 90 can be ejected onto the stage STA while passing through the print head unit 100. However, the disclosure is not limited thereto. Although the stage STA is shown to move in the drawings, in some embodiments, the stage STA can be fixed, and the print head unit 100 can move. In this case, the print head unit 100 can be mounted on a frame on the first rail RL1 and the second rail RL2.

[0189] The print head unit 100 can include a plurality of inkjet heads 300, and can be placed on the base frame 600. The print head unit 100 can eject a set or predetermined ink 90 onto a target substrate SUB by using the inkjet heads 300 connected (e.g., physically coupled) to a separate ink storage unit.

[0190] The base frame 600 can include a support unit 610 and a moving unit 630. The support unit 610 can include a first support 611 extending in a first direction DR1 (a horizontal direction) and a second support 612 connected (e.g., physically coupled) to the first support 611 and extending in a third direction DR3 (a vertical direction). The extension direction of the first support 611 can be the same as the first direction DR1. The print head unit 100 can be placed on the moving unit 630 mounted on the first support 611.

[0191] The moving unit 630 can include a moving part 631 mounted on the first support 611 and moving in one direction, and a fixed part 632 on a lower surface of the moving part 631 and provided with the printhead unit 100. The moving part 631 can move on the first support 611 in the first direction DR1, and the printhead unit 100 can be fixed to the fixed part 632 and move together with the moving part 631 in the first direction DR1.

[0192] The printhead unit 100 can be on the base frame 600 and eject ink 90 provided from an ink storage unit onto a target substrate SUB through the inkjet head 300. The printhead unit 100 can be spaced apart from the stage STA passing under the base frame 600 by a set or specific distance. The distance between the printhead unit 100 and the stage STA can be adjusted by the height of the second support 612 of the base frame 600. The distance between the printhead unit 100 and the stage STA can be adjusted within a range capable of securing a space required for a printing process, so that the printhead unit 100 has a certain (proper) distance from the target substrate SUB when the target substrate SUB is on the stage STA.

[0193] According to one or more embodiments, the printhead unit 100 can include an inkjet head 300 having a plurality of nozzles 350 (see Figure 10 ) on a lower surface thereof.

[0194] The plurality of inkjet heads 300 can be arranged to be spaced apart from each other in one direction, and can be arranged in one or more rows. In the drawings, the inkjet heads 300 are arranged in two rows, and the inkjet heads 300 in each row are arranged alternately with each other. However, the disclosure is not limited thereto, and the inkjet heads 300 can be arranged in a larger number of rows, and can be arranged to overlap each other without crossing each other. The shape of the inkjet head 300 is not particularly limited, but as an example, the inkjet head 300 can have a rectangular shape.

[0195] At least one inkjet head 300, for example, two inkjet heads 300 adjacent to each other, can form one group. However, the number of inkjet heads 300 included in one group is not limited thereto, and as an example, the number of inkjet heads 300 included in one group can be 1 to 5. Although it is shown in the drawings that the printhead unit 100 is provided with only six inkjet heads 300, this is for illustratively showing the printhead unit 100, and the number of inkjet heads 300 is not limited thereto.

[0196] The inkjet head 300 on the print head unit 100 can eject the ink 90 onto the target substrate SUB on the stage STA. According to one or more embodiments, the print head unit 100 can move on the first support 611 in one direction, and the inkjet head 300 can move in one direction to eject the ink 90 onto the target substrate SUB.

[0197] The print head unit 100 can move in a first direction DR1 in which the first support 611 extends, and the inkjet head 300 can move in the first direction DR1 to eject the ink 90 onto the target substrate SUB.

[0198] In one or more embodiments, the ink 90 can include a solvent 91 and a plurality of particles 95 included in the solvent 91. In one or more embodiments, the ink 90 can be provided in a solution or colloid state. Examples of the solvent 91 can include, but are not limited to, acetone, water, ethanol, toluene, propylene glycol (PG), 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, and ethyl glycol phthalate. The plurality of particles 95 can be included in a state of being dispersed in the solvent 91 and supplied to the print head unit 100 to be discharged.

[0199] In some embodiments, a width of the target substrate SUB measured in the first direction DR1 can be greater than a width of the print head unit 100. In this case, the print head unit 100 can move in the first direction DR1 and can completely eject the ink 90 onto the target substrate SUB. When a plurality of target substrates SUB is provided, the print head unit 100 can eject the ink 90 onto the plurality of target substrates SUB while moving in the first direction DR1, respectively.

[0200] However, the present disclosure is not limited thereto, and the print head unit 100 can be located outside the first rail RL1 and the second rail RL2 and then move in the first direction DR1 to eject the ink 90 onto the target substrate SUB. When the stage STA moves in the second direction DR2 and is located under the base frame 600, the print head unit 100 can move between the first rail RL1 and the second rail RL2 to eject the ink 90 through the inkjet head 300. The operation of the inkjet head 300 is not limited thereto, and various appropriate modifications can be made within a range capable of achieving a similar process.

[0201] The inkjet printing apparatus 1000 can further include an ink circulation unit 500. The ink circulation unit 500 can supply the ink 90 to the printhead 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. A portion of the ink 90 supplied to the inkjet head 300 can be discharged from the inkjet head 300, and the remaining ink 90 can be supplied back to the ink circulation unit 500.

[0202] The ink circulation unit 500 can be connected (e.g., physically coupled) to the inkjet head 300 through a first connection pipe IL1 and a second connection pipe IL2. For example, the ink circulation unit 500 can supply the ink 90 to the inkjet head 300 through the first connection pipe IL1, and can adjust the flow rate of the supplied ink 90 through a first valve VA1. Also, the ink 90 remaining after being discharged from the inkjet head 300 can be supplied to the ink circulation unit 500 through the second connection pipe IL2. The flow rate of the ink 90 supplied to the ink circulation unit 500 through the second connection pipe IL2 can be adjusted through a second valve VA2. As the ink 90 circulates through the ink circulation unit 500, the variation in the number of particles 95 included in the ink 90 discharged from the inkjet head 300 can be reduced or minimized.

[0203] The ink circulation unit 500 can be mounted on the base frame 600, but the present disclosure is not limited thereto. The ink circulation unit 500 is provided in the inkjet printing apparatus 1000, but its position and / or shape are not particularly limited. For example, the ink circulation unit 500 can be provided through a separate device, and various appropriate modifications can be made as long as it is connected (e.g., coupled) to the inkjet head 300.

[0204] In some embodiments, the ink circulation unit 500 can 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. In the ink circulation unit 500, the second ink storage unit 520, the pressure pump 550, and the third ink storage unit 530 are connected (e.g., physically coupled) to the inkjet head 300, and can form one ink circulation system.

[0205] The first ink storage unit 510 can be a storage unit in which the prepared ink 90 is stored. The ink 90 including the solvent 91 and the particles 95 can be stored in the first ink storage unit 510 of the ink circulation unit 500, and can be supplied to the ink circulation system.

[0206] The second ink storage unit 520 is connected (e.g., physically coupled) to the first ink storage unit 510, and the stored ink 90 can be supplied to the second ink storage unit 520. Also, 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 connection tube IL2. The second ink storage unit 520 can be located between the inkjet head 300 and the first ink storage unit 510 to constitute an ink circulation system together with the third ink storage unit 530. When the second ink storage unit 520 is omitted, the excess ink 90 can be supplied to the third ink storage unit 530, so that the dispersion of the particles 95 can not be easy. The ink circulation unit 500 can further include the second ink storage unit 520 to reduce or prevent the excess ink 90 from being supplied to the third ink storage unit 530. For example, the second ink storage unit 520 can function as a buffer storage unit in which a part of the ink 90 circulating in the ink circulation system is stored.

[0207] The ink 90 supplied to the second ink storage unit 520 can be supplied to the third ink storage unit 530 through the pressure pump 550. The pressure pump 550 can be a pump that transmits power to a fluid (e.g., promotes the movement of the fluid) so that the ink 90 can circulate in the ink circulation system. The ink 90 supplied to the second ink storage unit 520 can be supplied to the third ink storage unit 530 through the pressure pump 550. The flow meter 580 can be disposed between the pressure pump 550 and the third ink storage unit 530, and 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.

[0208] The ink circulation unit 500 can further include the compressor 560, and the compressor 560 can adjust the pressure in the third ink storage unit 530. The compressor 560 can remove gas so that the inside of the third ink storage unit 530 is in a vacuum state, or can introduce an external inert gas to have a set or predetermined pressure. However, the present disclosure is not limited thereto, and the compressor 560 of the ink circulation unit 500 can be omitted.

[0209] The third ink storage unit 530 can be connected (e.g., physically coupled) to the second ink storage unit 520 by a pressure pump 550 to allow the ink 90 to be supplied to the third ink storage unit 530. In one or more embodiments, the third ink storage unit 530 can supply the ink 90 to the inkjet head 300 through the first connection tube IL1. In one or more embodiments, the third ink storage unit 530 can include a stirrer ST, and the stirrer ST can disperse the particles 95 in the ink 90. The ink 90 supplied to the third ink storage unit 530 can be maintained in a state in which the particles 95 are dispersed without sinking when the stirrer ST is rotated. For example, the stirrer ST of the third ink storage unit 530 can cause the particles 95 not to sink below (e.g., to the bottom of) the third ink storage unit 530, thereby reducing or preventing a decrease in the number of particles 95 in the ink 90 discharged through the inkjet head 300. The third ink storage unit 530 can supply the ink 90 in which the particles 95 are dispersed to the inkjet head 300, and the inkjet head 300 can discharge the ink 90 including the particles 95 at a set or predetermined level (e.g., amount) or higher.

[0210] In one or more embodiments, in the inkjet printing apparatus 1000, the unit droplet amount of the ink 90 discharged from the inkjet head 300 needs to be constant (or substantially constant), and at the same time (or simultaneously), the number of particles 95 dispersed in the unit droplet amount needs to be uniformly (or substantially uniformly) controlled. When the number of particles 95 per unit droplet of the ink 90 is not uniform when the ink 90 is ejected from the inkjet head 300 through the ink circulation system, the reliability of the inkjet printing apparatus 1000 can be problematic. Accordingly, it can cause a difference in brightness of the display device 10, thereby deteriorating the display quality.

[0211] According to one or more embodiments, the inkjet printing apparatus 1000 can maintain the flow rate of the ink 90 in the internal flow path through which the ink 90 is supplied by forming a slope on one surface of the base on the inkjet head 300. Accordingly, by reducing or preventing the sedimentation of the particles 95 dispersed in the ink 90, the number of particles 95 discharged into a unit space can be uniformly (or substantially uniformly) maintained.

[0212] Hereinafter, the inkjet head 300 will be described in greater detail.

[0213] Figure 10 FIG. 1 is a schematic cross-sectional view illustrating an example of an inkjet head according to one or more embodiments. Figure 11 and Figure 12 are cross-sectional views schematically illustrating other examples of an inkjet head according to one or more embodiments, respectively.

[0214] Reference Figure 10 The inkjet head 300 can include a plurality of nozzles 350, and can discharge ink 90 through the nozzles 350. The ink 90 discharged from the nozzles 350 can be ejected onto a target substrate SUB disposed on a stage STA. The nozzles 350 can be located at a bottom of the inkjet head 300, and can be arranged along a direction in which the inkjet head 300 extends.

[0215] The inkjet head 300 can include a base 310, an internal flow path 330, and a plurality of nozzles 350. The inkjet head 300 can further include a discharge portion 370.

[0216] The base 310 can constitute a main body of the inkjet head 300. The base 310 can be attached to the print head unit 100. The base 310 can have a shape extending in a first direction DR1 and a second direction DR2. However, the present disclosure is not limited thereto, and the base 310 can have a circular shape or a polygonal shape.

[0217] The discharge portion 370 can be a portion of the base 310 of the inkjet head 300 in which the nozzles 350 are disposed. Figure 10 It is illustrated that the discharge portions 370 disposed in connection with the base 310 and spaced apart from the base 310 are provided, and the nozzles 350 are formed therebetween. However, substantially all of the discharge portions 370 can be one member that is not spaced apart from each other and integrated with each other (e.g., is integral), and the nozzles 350 can be formed in the shape of holes penetrating the discharge portions 370. For example, the plurality of discharge portions 370 can be not spaced apart from each other and can be formed as one member. However, the present disclosure is not limited thereto, and in some embodiments, the inkjet head 300 can include a plurality of units including the discharge portions 370 on which the nozzles 350 are formed. In this case, the plurality of discharge portions 370 can be spaced apart from each other and connected (e.g., physically coupled) to the base 310.

[0218] The internal flow path 330 can be in the base 310 to allow the ink 90 to be supplied through the internal flow path 330 from the ink circulation unit 500. In the print head unit 100, the ink 90 can be supplied through a first connection tube IL1 connected (e.g., physically coupled) to the ink circulation unit 500, and the ink 90 remaining after being discharged from the nozzles 350 can be supplied to the ink circulation unit 500 through a second connection tube IL2. In the internal flow path 330 of the inkjet head 300, the ink 90 can be supplied through an inlet 331 of the print head unit 100, and the ink 90 remaining after being discharged can be discharged through an outlet 333 of the print head unit 100.

[0219] The base 310 can have a shape extending in one direction, and the internal flow path 330 can be formed along the extension direction of the base 310. The ink 90 supplied through the printhead unit 100 can flow through the internal flow path 330, and then be discharged through the nozzles 350 of the inkjet head 300.

[0220] The plurality of nozzles 350 can be in a discharge portion 370 located on one surface of the base 310 (e.g., a lower surface of the base 310). The plurality of nozzles 350 can be spaced apart from each other and arranged along the extension direction of the base 310, can pass through the discharge portion 370 of the base 310, and can be connected to the internal flow path 330 to discharge the ink 90. In one or more embodiments, the plurality of nozzles 350 can be arranged in one or more rows. In addition, the number of nozzles 350 included in the inkjet head 300 can be 128 to 1800. The nozzles 350 can discharge the ink 90 introduced along the internal flow path 330. The amount of ink 90 discharged at one time (e.g., at one time) from each nozzle 350 can be about 1 pL to about 50 pL (picoliter), but is not limited thereto.

[0221] The plurality of particles 95 are dispersed in the ink 90 discharged from the inkjet head 300. Depending on the degree of dispersion of the particles 95, the ink 90 discharged at one time (e.g., at one time) from the nozzle 350 can include a set or specific number of particles 95. In the internal flow path 330 in the inkjet head 300, the flow rate of the ink 90 gradually decreases from the inlet 331 toward the outlet 333, and thus the particles 95 can be precipitated in the internal flow path 330 adjacent to the outlet 333. In this case, the degree of dispersion of the particles 95 in the ink 90 can not remain constant, and the number of particles 95 in the ink 90 discharged at one time (e.g., at one time) can change.

[0222] According to one or more embodiments, the base 310 can have a slope on one surface contacting the internal flow path 330. The base 310 can include a first surface 312 contacting the internal flow path 330. The first surface 312 of the base 310 can be a surface forming the internal flow path 330. The first surface 312 can have a set or predetermined slope (e.g., inclination) along the first direction DR1.

[0223] For example, the first surface 312 of the base 310 can be spaced apart from one surface of the discharge portion 370 by a set or predetermined distance, e.g., from one surface of the discharge portion 370 facing the base 310. The distance can be a diameter of the internal flow path 330 in the third direction DR3. One point of the first surface 312 (e.g., upper) of the base 310 can be spaced apart from the discharge portion 370 by a first distance dl in a direction perpendicular to an extension direction of the discharge portion 370 (i.e., in the third direction DR3). The one point of the first surface 312 of the base 310 can be on a side of the base 310 adjacent to the inlet 331 to which the ink 90 is supplied. Further, another point of the first surface 312 (e.g., upper) of the base 310 can be spaced apart from the discharge portion 370 by a second distance d2 in the third direction DR3 perpendicular to the extension direction of the discharge portion 370. The other point of the first surface 312 of the base 310 can be on another side of the base 310 adjacent to the outlet 333 from which the ink 90 is discharged.

[0224] Because the first surface 312 of the base 310 has a slope, the first distance dl can be greater (e.g., longer) than the second distance d2. For example, a diameter of the internal flow path 330 adjacent to the inlet 331 can be greater than a diameter of the internal flow path 330 adjacent to the outlet 333. As described above, a flow rate of the ink 90 supplied from the inlet 331 can decrease toward the outlet 333. When the flow rate decreases, the particles 95 included in the ink 90 can settle in the internal flow path 330 adjacent to the outlet 333, resulting in a decrease in the number of the particles 95 discharged from the nozzle 350 adjacent to the outlet 333.

[0225] In one or more embodiments, the second distance d2 can be shorter than the first distance dl. For example, a diameter of the internal flow path 330 adjacent to the outlet 333 can be smaller than a diameter of the internal flow path 330 adjacent to the inlet 331, such that a decrease in the flow rate of the ink 90 can be reduced or prevented, thereby maintaining the flow rate constant (or substantially constant). Accordingly, the particles 95 can not settle in the internal flow path 330 adjacent to the outlet 333 and can be discharged through the nozzle 350.

[0226] The second distance d2 can be 90% to 99% of the first distance dl. When the second distance d2 is 99% or less of the first distance dl, a decrease in the flow rate of the ink 90 can be reduced or prevented. When the second distance d2 is 90% or more of the first distance dl, a decrease in the amount of discharge of the ink 90 through the nozzle 350 can be reduced or prevented.

[0227] In some embodiments, the distance between the first surface 312 and the discharge portion 370 can gradually decrease from one side of the first surface 312 of the base 310 toward the other side thereof. For example, the diameter of the internal flow path 330 can gradually decrease from the inlet 331 toward the outlet 333. Accordingly, it is possible to maintain the flow rate constant (or substantially constant) by reducing or preventing the reduction of the flow rate of the ink 90.

[0228] In one or more embodiments, the first surface 312 of the base 310 can include the protrusion 315 to have the inclination (e.g., slope).

[0229] Referring to Figure 11 , the protrusion 315 can be on one side of the first surface 312 of the base 310 adjacent to the outlet 333. The protrusion 315 can have an increased (e.g., gradually increased) thickness measured in the third direction DR3, and thus can have the inclination. The protrusion 315 can be on the first surface 312 adjacent to the outlet 333 to reduce the diameter of the internal flow path 330 in the corresponding portion thereof.

[0230] In one or more embodiments, one point of the protrusion 315 can be spaced apart from one surface of the discharge portion 370 by a third distance d3. One point of the protrusion 315 can be on one side of the protrusion 315 adjacent to the outlet 333, and one surface of the discharge portion 370 can be a surface facing the protrusion 315. The above-described first distance d1 can be longer than the third distance d3. For example, the third distance d3 can be shorter than the first distance d1. Accordingly, it is possible to reduce or prevent the reduction of the flow rate of the ink 90 in the region adjacent to the outlet 333 to maintain the flow rate constant (or substantially constant), and thus the particles 95 can not be precipitated in the internal flow path 330 adjacent to the outlet 333, and can be discharged through the nozzle 350.

[0231] Referring to Figure 12 , as another example, the protrusion 315 can have an inclination of 90°. The protrusion 315 can be formed in a bar shape of a cuboid, and can be spaced apart from the discharge portion 370 by the third distance d3. However, the present disclosure is not limited thereto, and the protrusion 315 can be formed in a shape of a polygonal column or a lenticular lens, and can have any suitable shape as long as it is possible to reduce the distance between the first surface 312 of the base 310 and the discharge portion 370.

[0232] Although the protrusion 315 is shown to be provided on the first surface 312 of the base 310 as an additional component in the drawings, the present disclosure is not limited thereto, and the protrusion 315 can be integrally formed (one body) with the base 310.

[0233] Figure 13 is a schematic cross-sectional view of an inkjet head according to one or more other embodiments.

[0234] Reference Figure 13 In the inkjet head 300, the first surface 312 of the base 310 can have a slope. The present embodiment differs from the above-described embodiment of the inkjet head 300 in that the diameters of the nozzles 350 are different from each other. Hereinafter, the difference will be described in more detail, and a repetitive description will not be provided for the same configuration. Figures 10 to 12

[0235] The inkjet head 300 according to one or more embodiments can include a plurality of nozzles 350. The plurality of nozzles 350 can include a first nozzle 352 adjacent to the inlet 331 and a second nozzle 353 adjacent to the outlet 333. The first nozzle 352 and the second nozzle 353 can have a set or predetermined diameter such that the ink 90 can be discharged. The diameter of the nozzles 352 and 353 can be a diameter in the first direction DR1.

[0236] The diameter D1 of the first nozzle 352 can be greater than the diameter D2 of the second nozzle 353, and thus, the diameter D2 of the second nozzle 353 can be less than the diameter D1 of the first nozzle 352. For example, the diameter D1 of the first nozzle 352 adjacent to the inlet 331 can be greater 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 can decrease toward the outlet 333. When the flow rate decreases, the particles 95 included in the ink 90 can be precipitated in a portion of the internal flow path 330 adjacent to the outlet 333, thereby causing a decrease in the number of the particles 95 discharged from the nozzles 350 adjacent to the outlet 333.

[0237] In one or more embodiments, the diameter D2 of the second nozzle 353 can be less than the diameter D1 of the first nozzle 352. For example, the diameter D2 of the second nozzle 353 adjacent to the outlet 333 can be less than the diameter D1 of the first nozzle 352 adjacent to the inlet 331, such that a decrease in the flow rate of the ink 90 discharged through the second nozzle 353 can be reduced or prevented, thereby maintaining the flow rate constant (or substantially constant). Accordingly, the particles 95 can not be precipitated in the internal flow path 330 adjacent to the outlet 333 and can be discharged through the second nozzle 353.

[0238] The diameter D2 of the second nozzle 353 can be 90% to 99% of the diameter D1 of the first nozzle 352. When the diameter D2 of the second nozzle 353 is 99% or less of the diameter D1 of the first nozzle 352, a decrease in the flow rate of the ink 90 can be reduced or prevented. When the diameter D2 of the second nozzle 353 is 90% or more of the diameter D1 of the first nozzle 352, a decrease in the amount of the ink 90 discharged through the nozzles 350 can be reduced or prevented.

[0239] ​The discharge portion 370 can further include a third nozzle 354 adjacent to the second nozzle 353. The third nozzle 354 can be closer to the inlet 331 than the second nozzle 353. The third nozzle 354 can have a set or predetermined diameter D3, and the diameter D3 of the third nozzle 354 can be greater than the diameter D2 of the second nozzle 353. Because the flow rate of the ink 90 supplied to the internal flow path 330 can decrease toward the outlet 333, the diameter D3 of the third nozzle 354, which is closer to the inlet 331 than the second nozzle 353, can be greater than the diameter D2 of the second nozzle 353. However, because the flow rate of the ink 90 in the first nozzle 352, which is closest to the inlet 331, does not decrease, the diameter D1 of the first nozzle 352 can be the greatest, and the diameter D3 of the third nozzle 354 can be less than the diameter D1 of the first nozzle 352.

[0240] In some embodiments, the diameter of the nozzles 350 can gradually decrease from the inlet 331 toward the outlet 333. Accordingly, it is possible to maintain the flow rate constant (or substantially constant) by reducing or preventing the flow rate of the ink 90 from gradually decreasing toward the outlet 333.

[0241] Figure 14 is a schematic cross-sectional view of an inkjet head according to one or more other embodiments. Figure 15 is a plan view schematically showing an example of a bottom surface of a base and a rotating member according to one or more other embodiments. Figure 16 is a plan view schematically showing another example of a bottom surface of a base and a rotating member according to one or more other embodiments.

[0242] Reference Figure 14 and Figure 15 The inkjet head 300 can include a base 310, a discharge portion 370, and an internal flow path 330. The present embodiment differs from the above-described Figures 10 to 12 embodiment in that the base 310 does not have an inclination, and a rotating member 700 is disposed in the internal flow path 330. Hereinafter, the differences will be described in more detail, and a repetitive description of the same configuration will not be provided.

[0243] In one or more embodiments, the rotating member 700 can be disposed in the internal flow path 330. The rotating member 700 can be passively rotated according to the flow of the ink 90 to mix the ink 90 supplied to the internal flow path 330. The rotation speed of the rotating member 700 can be substantially the same as the flow rate of the ink 90.

[0244] In one or more embodiments, the rotating member 700 can include a rotating shaft 710 fixed to the base 310 and a blade 720 coupled to the rotating shaft 710 and rotating in one direction. The rotating shaft 710 can be on one surface of the base 310 facing the discharge portion 370. The rotating shaft 710 can be at the center of one surface of the base 310. The blade 720 can be formed as a pair of left and right blades extending in a horizontal direction around the rotating shaft 710. Although it is shown in FIG. 7 that the blade 720 can be formed as a pair of left and right blades, the present disclosure is not limited thereto, and two or more pairs of blades can be provided. Also, an odd number of blades, for example, three or five blades, can be provided instead of a pair of blades. Figure 14 In one or more embodiments, the rotating member 700 can include a rotating shaft 710 fixed to the base 310 and a blade 720 coupled to the rotating shaft 710 and rotating in one direction. The rotating shaft 710 can be on one surface of the base 310 facing the discharge portion 370. The rotating shaft 710 can be at the center of one surface of the base 310. The blade 720 can be formed as a pair of left and right blades extending in a horizontal direction around the rotating shaft 710. Although it is shown in FIG. 7 that the blade 720 can be formed as a pair of left and right blades, the present disclosure is not limited thereto, and two or more pairs of blades can be provided. Also, an odd number of blades, for example, three or five blades, can be provided instead of a pair of blades.

[0245] The blade 720 can have a set or predetermined length so as to easily (or appropriately) mix the ink 90 moving through the internal flow path 330. The length L1 of the blade 720 can be shorter than the length L2 from the rotating shaft 710 to one side surface of the base 310. The radius of rotation of the blade 720 can be determined by the length L1 of the blade 720, and the blade 720 can protrude from one side of the base 310 so that the blade 720 does not interfere with the side wall of the internal flow path 330. In some embodiments, the length L1 of the blade 720 can be substantially the same as the length L2 from the rotating shaft 710 to one side surface of the base 310.

[0246] Referring to FIG. 8, Figure 16 A plurality of rotating members 700 can be provided in the base 310. The plurality of rotating members 700 can include a first rotating member 740 at the center of the base 310 and second rotating members 750a, 750b, 750c, and 750d at one or more corners of the base 310.

[0247] The first rotating member 740 can include a blade having a set or predetermined length, and can rotate at a set or predetermined radius of rotation. The second rotating members 750a, 750b, 750c, and 750d can be in a region outside the radius of rotation of the first rotating member 740 to mix the ink 90. The size of each of the second rotating members 750a, 750b, 750c, and 750d can be smaller than the size of the first rotating member 740. Here, the size of the rotating member refers to the diameter of the rotating shaft 710 and the length of the blade 720. Each of the second rotating members 750a, 750b, 750c, and 750d has a relatively small size, and the ink 90 can be mixed in a region outside the radius of rotation of the first rotating member 740.

[0248] The inkjet head 300 of the inkjet printing device 1000 according to the above-described embodiment includes a rotation member 700 so that the ink 90 moving through the internal flow path 330 can be mixed. The plurality of particles 95 included in the ink 90 can be mixed by the rotation member 700 and supplied to the nozzle 350 so that the particles 95 can be uniformly (or substantially uniformly) discharged without being precipitated in the internal flow path 330.

[0249] Figure 17 is a schematic cross-sectional view of an inkjet head according to one or more other embodiments. Figure 18 is a cross-sectional view schematically illustrating a state in which a precipitation-preventing member and particle vibration. Figure 19 is a view schematically illustrating a state in which particles are charged. Figure 20 is a schematic cross-sectional view of an inkjet head according to one or more other embodiments.

[0250] Reference Figure 17 , the inkjet head 300 can include a base 310, a discharge portion 370, and an internal flow path 330. The present embodiment differs from the above-described embodiment of the inkjet head 300 in that a side wall portion 1100 of the inkjet head 300 is provided with a precipitation-preventing member 800. Hereinafter, the difference will be described in more detail, and a repetitive description of the same configuration will not be provided. Figures 14 to 16

[0251] In one or more embodiments, the inkjet head 300 can further include a side wall portion 1100 forming a side wall of the internal flow path 330. The side wall portion 1100 can be adjacent to the base 310, and the internal flow path 330 is between them. The side wall portion 1100 can extend from the discharge portion 370 in a third direction DR3.

[0252] The side wall portion 1100 can 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 can be spaced apart from each other, and the base 310 is between them, and the first side wall portion 1110 and the second side wall portion 1120 can be parallel to each other.

[0253] ​The sidewall portion 1100 may be provided with an anti-settling member 800 capable of mixing and dispersing a plurality of particles 95 in the ink 90. ​​For example, the anti-settling member 800 may include a first anti-settling member 810 and a second anti-settling member 820. The first anti-settling member 810 may be in the first sidewall portion 1110, and the second anti-settling member 820 may be in the second sidewall portion 1120. The anti-settling members 810 and 820 may be inserted into the sidewall portions 1110 and 1120, respectively, so as not to interfere with the movement of the ink 90 moving through the internal flow path 330. One surface of each of the anti-settling members 810 and 820 may be exposed to the internal flow path 330. One surface of each of the anti-settling members 810 and 820 may contact the ink 90 moving through the internal flow path 330.

[0254] In one or more embodiments, each of the anti-settling components 810 and 820 may be an ultrasonic vibrator. The ultrasonic vibrator may generate ultrasonic vibrations in one direction to vibrate the ink 90 moving in the internal flow path 330. The ink 90 may be vibrated vertically or horizontally in a plane by the ultrasonic waves generated from the ultrasonic vibrator.

[0255] An ultrasonic vibrator can be configured as a transducer capable of converting AC power into ultrasonic vibration. Alternatively, an ultrasonic vibrator can be configured as a piezoelectric element capable of converting electrical signals into vibration signals. The power required to apply the ultrasonic vibration can be supplied from an external power supply unit. In one or more embodiments, in addition to the external power supply unit, a display in which the ultrasonic frequency and amplitude are displayed as digital values ​​or waveform curves may also be provided.

[0256] like Figure 18 As shown, in the first anti-settling member 810, which is formed as an ultrasonic vibrator, ultrasonic vibration can be generated in the first direction DR1, and in the second anti-settling member 820, which is formed as an ultrasonic vibrator, ultrasonic vibration can be generated in the direction opposite to the first direction DR1. The ink 90 and the particles 95 dispersed in the ink 90 can be mixed by horizontal vibration through ultrasonic vibration.

[0257] As described above, by providing an anti-settling member 800 formed as an ultrasonic vibrator, a plurality of particles 95 included in the ink 90 can be mixed by ultrasonic vibration. Therefore, the particles 95 are supplied to the nozzle 350 without settling in the internal flow path 330, so that a uniform (or substantially uniform) number of particles 95 can be discharged.

[0258] refer to Figure 17 and Figure 19In one or more other embodiments, each of the anti-settling members 810 and 820 may be a charging plate. The charging plate may be an electrode to which a positive or negative voltage is applied. The charging plate may charge the ink particles 95 in contact with the charging plate with positive (+) or negative (-) charges. In the ink 90, the particles 95 may be charged with the same (+) or (-) charge to create a repulsive force between them. The charging plate may receive the power required to charge the particles 95 from an external power supply unit.

[0259] refer to Figure 20 In this embodiment, the first anti-settling member 810 may be provided only in the second sidewall portion 1120. As described above, because the flow rate of ink 90 decreases in the internal flow path 330 adjacent to the outlet 333, resulting in the sedimentation of particles 95, the first anti-settling member 810 may be provided in the second sidewall portion 1120 adjacent to the outlet 333 to reduce or prevent the sedimentation of particles 95. However, this disclosure is not limited thereto, and the first anti-settling member 810 may be provided only in the first sidewall portion 1110 adjacent to the inlet 331.

[0260] The inkjet printing head 300 of the inkjet printing apparatus 1000 according to the above embodiment includes an anti-settling member 800, which disperses the ink particles 95 moving in the internal flow path 330. A plurality of particles 95 included in the ink 90 can be dispersed by the anti-settling member 800 and supplied to the nozzle 350, so that a uniform (or substantially uniform) number of particles 95 can be discharged without settling in the internal flow path 330. Therefore, the number of particles 95 per unit droplet of ink 90 can be made uniform (or substantially uniform), and brightness differences in the display device 10 can be reduced or prevented.

[0261] In concluding this detailed description, those skilled in the art will understand that many variations and modifications can be made to the embodiments without substantially departing from the principles of the invention as defined by the appended claims and their equivalents. Therefore, the embodiments disclosed herein are used in a general and descriptive sense only and not for limiting purposes.

Claims

1. An inkjet printing apparatus comprising: a stage; and an inkjet head above the stage and including a plurality of nozzles through which ink including a plurality of particles is discharged, wherein the inkjet head includes: a base constituting a main body of the inkjet head; a discharge portion adjacent to the base and including the plurality of nozzles; and an internal flow path between the base and the discharge portion and configured to accommodate the ink, and wherein the base includes a first surface contacting the internal flow path, and at least a portion of the first surface is inclined, and wherein an entire surface of the internal flow path adjacent to the discharge portion is flat.

2. The inkjet printing apparatus according to claim 1, wherein a first distance from a point of the first surface of the base to the discharge portion is longer than a second distance from another point of the first surface to the discharge portion.

3. The inkjet printing apparatus according to claim 2, wherein the inkjet head further includes an inlet through which the ink is supplied and an outlet through which the ink is discharged, the inlet and the outlet are in the internal flow path, and the point of the first surface is on one side of the base adjacent to the inlet, and the other point of the first surface is on another side of the base adjacent to the outlet.

4. The inkjet printing apparatus according to claim 3, wherein, the second distance is 90% to 99% of the first distance.

5. The inkjet printing apparatus according to claim 3, wherein a distance between the first surface and the discharge portion gradually decreases from one end of the first surface of the base toward another end thereof.

6. The inkjet printing apparatus according to claim 3, wherein the plurality of nozzles includes a first nozzle adjacent to the inlet and a second nozzle adjacent to the outlet, and a diameter of the first nozzle is larger than a diameter of the second nozzle.

7. The inkjet printing apparatus according to claim 6, wherein the diameter of the second nozzle is 90% to 99% of the diameter of the first nozzle.

8. The inkjet printing apparatus according to claim 6, wherein, the plurality of nozzles further includes a third nozzle between the first nozzle and the second nozzle, the third nozzle is adjacent to the second nozzle, and a diameter of the third nozzle is larger than the diameter of the second nozzle and smaller than the diameter of the first nozzle.

9. The inkjet printing apparatus according to claim 3, wherein a diameter of a portion of the internal flow path adjacent to the outlet is smaller than a diameter of a portion of the internal flow path adjacent to the inlet.

10. The inkjet printing apparatus according to claim 3, wherein a diameter of the internal flow path gradually decreases from the inlet toward the outlet.

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