Organic light emitting display device

Abstract

An organic light-emitting display device according to one embodiment of the present invention comprises a substrate having a plurality of subpixels arranged thereon, at least one thin-film transistor disposed on each of the plurality of subpixels, a first electrode of an organic light-emitting diode connected to the thin-film transistor, a first bank layer exposing the first electrode, and a second bank layer disposed on the first bank layer and exposing the first bank layer and the first electrode, wherein the first bank layer includes a first region that overlaps with a via hole connecting the thin-film transistor and the first electrode, and a second region which is the remaining region excluding the first region, and the thickness of the first region may be thicker than the thickness of the second region.

Description

Technology Field

[0001] The present invention relates to an organic light-emitting display device having a heterogeneous bank structure. Background Technology

[0002] Recently, various display devices are being developed to reduce the weight and volume, which are disadvantages of Cathode Ray Tubes. These display devices include Liquid Crystal Displays (LCDs), Plasma Display Panels (PDPs), Field Emission Displays (FEDs), and Organic Light Emitting Display Devices.

[0003] Organic light-emitting display devices are self-luminous devices that emit light on their own and have the advantages of fast response speed, high luminous efficiency, brightness, and viewing angle. In addition, since the devices can be formed on flexible substrates such as plastic, flexible display devices can be realized.

[0004] Recently, as there is a demand for large-area, high-resolution organic light-emitting displays, a single panel contains multiple subpixels. Generally, a mask is used to pattern the light-emitting layers of red (R), green (G), and blue (B) subpixels. To implement large-area displays, a large-area fine metal mask (FMM) corresponding to a large-area substrate is required. However, as the area increases, mask sagging occurs, leading to various defects such as the organic light-emitting material constituting the light-emitting layer not being deposited at the desired location.

[0005] To address the problems of the aforementioned mask-based deposition method, a solution process that is simple and advantageous for large areas is attracting attention. The solution process enables the patterning of large-area light-emitting layers without a mask through inkjet printing or nozzle printing, and has a very high material utilization rate of 50 to 80% compared to vacuum deposition, which has a material utilization rate of 10% or less. In addition, compared to vacuum-deposited thin films, it has a higher glass transition temperature, resulting in excellent thermal stability and morphological characteristics. The problem to be solved

[0006] However, when forming a light-emitting layer through a solution process, non-uniformity in the thickness of the light-emitting layer occurs due to thickness variations within subpixels, resulting in a problem where display quality is significantly degraded.

[0007] Accordingly, the present invention aims to provide an organic light-emitting display device having a heterogeneous bank structure. means of solving the problem

[0008] An organic light-emitting display device according to one embodiment of the present invention comprises a substrate having a plurality of subpixels arranged thereon, at least one thin-film transistor disposed on each of the plurality of subpixels, a first electrode of an organic light-emitting diode connected to the thin-film transistor, a first bank layer exposing the first electrode, and a second bank layer disposed on the first bank layer and exposing the first bank layer and the first electrode, wherein the first bank layer includes a first region that overlaps with a via hole connecting the thin-film transistor and the first electrode, and a second region which is the remaining region excluding the first region, and the thickness of the first region may be thicker than the thickness of the second region.

[0009] The second bank layer above may be placed between subpixels emitting different colors among the plurality of subpixels.

[0010] The first region above may be placed between subpixels emitting the same color among the plurality of subpixels.

[0011] The first region and the second region may not overlap.

[0012] The above second region can overlap with the above second bank layer.

[0013] The first region above may be arranged to extend parallel to the direction in which the short side of the plurality of subpixels is extended.

[0014] The first region above may overlap by intersecting with the second bank layer.

[0015] The above second region may be spaced apart from each other with the above first region in between.

[0016] The second region above may be arranged to extend parallel to the direction in which the long side of the plurality of subpixels is extended.

[0017] The second region above may be arranged parallel to the second bank layer, overlapped, and arranged continuously.

[0018] The second region above may be placed between subpixels exhibiting the same and different colors among the plurality of subpixels.

[0019] The first region above may be spaced apart from each other with the second region in between.

[0020] The first region above may not overlap with the second bank layer.

[0021] The above via hole may include a first via hole of a passivation film that exposes either the source or drain electrode of the thin-film transistor, and a second via hole of an overcoat layer disposed on the passivation film that exposes the first via hole.

[0022] The first bank layer may have hydrophilicity, and the second bank layer may have hydrophobicity.

[0023] Additionally, an organic light-emitting display device according to one embodiment of the present invention comprises a substrate having a plurality of subpixels arranged thereon, a first electrode of an organic light-emitting diode disposed on each of the plurality of subpixels, a first bank layer exposing the first electrode, and a second bank layer disposed on the first bank layer and exposing the first bank layer and the first electrode, wherein the first bank layer comprises a first region disposed between subpixels emitting the same color among the plurality of subpixels and a second region which is the remaining region excluding the first region, and the thickness of the first region may be thicker than the thickness of the second region. Effects of the invention

[0024] The present invention can prevent the first electrode from being exposed to the upper part of the first bank layer and short-circuiting with the second electrode by forming the thickness of the first region of the first bank layer, which overlaps with the via hole, thicker, thereby mitigating the step difference of the via hole. In addition, even when foreign matter is present, the first region of the first bank layer, which has a thick thickness, suppresses the flow of organic light-emitting material, thereby preventing the thickness from becoming non-uniform.

[0025] In addition, the present invention can uniformly form an organic light-emitting layer by reducing the step difference between the first bank layer and the second bank layer by forming a second region that is thinner than the first region of the first bank layer. Accordingly, the display quality can be improved by reducing the brightness variation according to the position of the organic light-emitting layer. Furthermore, the process yield can be improved by reducing the difference in current density within the organic light-emitting layer, thereby preventing the deterioration of the device's lifespan and preventing the occurrence of dark spots. Brief explanation of the drawing

[0026] FIG. 1 is a schematic block diagram of an organic light-emitting display device. Figure 2 is a schematic circuit diagram of a subpixel. Figure 3 is a concrete circuit diagram of a subpixel. FIG. 4 is a schematic diagram showing the planar layout of a subpixel according to the present invention. FIG. 5 is a cross-sectional view taken along the cutting line I-I' of FIG. 4. FIG. 6 is a plan view showing an organic light-emitting display device according to a first embodiment of the present invention. FIG. 7 is a cross-sectional view taken along the cutting line II-II' of FIG. 6. FIG. 8 is a cross-sectional view taken along the cutting line Ⅲ-Ⅲ' of FIG. 6. FIG. 9 is a cross-sectional view showing the thickness non-uniformity of the organic light-emitting layer in the solution process. FIG. 10 is a cross-sectional view showing a defect in an organic light-emitting diode caused by foreign matter. FIG. 11 is a plan view showing an organic light-emitting display device according to a first embodiment of the present invention. FIG. 12 is a cross-sectional view taken along the cutting line Ⅳ-Ⅳ' of FIG. 11. FIG. 13 is a cross-sectional view taken along the cutting line V-V' of FIG. 11. FIG. 14 is a plan view showing an organic light-emitting display device according to a second embodiment of the present invention. FIG. 15 is a cross-sectional view taken along the cutting line VI-VI' of FIG. 14. FIG. 16 is a plan view showing an organic light-emitting display device according to a third embodiment of the present invention. FIG. 17 is a cross-sectional view taken along the cutting line Ⅶ-Ⅶ' of FIG. 16. Specific details for implementing the invention

[0027] The advantages and features of this specification and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, this specification is not limited to the embodiments disclosed below but may be implemented in various different forms; these embodiments are provided merely to ensure that the disclosure of this specification is complete and to fully inform those skilled in the art of the scope of this specification, and this specification is defined only by the scope of the claims.

[0028] Shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of this specification are exemplary and are not limited to the matters depicted in this specification. Throughout the specification, the same reference numerals refer to the same components. Furthermore, in describing this specification, if it is determined that a detailed description of related prior art could unnecessarily obscure the essence of this specification, such detailed description is omitted. Where terms such as "includes," "has," or "is made up" are used in this specification, other parts may be added unless "only" is used. Where a component is expressed in the singular, it includes cases where it is included in the plural unless specifically stated otherwise.

[0029] In interpreting the components, they are interpreted to include a margin of error even in the absence of a separate explicit statement.

[0030] In the case of describing a positional relationship, for example, when the positional relationship between two parts is described using expressions such as 'on top of,' 'above,' 'below,' or 'next to,' one or more other parts may be located between the two parts unless 'immediately' or 'directly' is used.

[0031] "First," "second," etc., may be used to describe various components, but these components are not limited by these terms. These terms are used merely to distinguish one component from another. Accordingly, the first component mentioned below may be the second component within the technical scope of this specification.

[0032] The features of each of the various embodiments of this specification may be combined or combined with one another, either partially or wholly, and may technically enable various interlocking and operation. Each embodiment may be implemented independently of one another or together in an associated relationship.

[0033] An electroluminescent display device according to an embodiment of the present specification will be described below with reference to the attached drawings. Throughout the specification, identical reference numerals denote substantially identical components. In the following description, if it is determined that a detailed description of a known function or configuration related to the present specification may unnecessarily obscure the gist of the specification, such detailed description will be omitted or briefly described.

[0034] The display device according to the present invention may be an organic light-emitting display device, a liquid crystal display device, an electrophoretic display device, etc., as examples of display devices, but the present invention describes an organic light-emitting display device as an example. The organic light-emitting display device includes an organic light-emitting layer made of an organic material between a first electrode, which is an anode, and a second electrode, which is a cathode. Accordingly, holes supplied from the first electrode and electrons supplied from the second electrode combine within the organic light-emitting layer to form excitons, which are hole-electron pairs, and the device is a self-luminous display device that emits light due to the energy generated as the excitons return to the ground state.

[0035] FIG. 1 is a schematic block diagram of an organic light-emitting display device, FIG. 2 is a schematic circuit diagram of a subpixel, and FIG. 3 is a concrete circuit diagram of a subpixel.

[0036] As illustrated in FIG. 1, the organic light-emitting display device (10) includes an image processing unit (11), a timing control unit (12), a data driving unit (13), a scan driving unit (14), and a display panel (20).

[0037] The image processing unit (11) outputs a data enable signal (DE), etc., along with a data signal (DATA) supplied from the outside. In addition to the data enable signal (DE), the image processing unit (11) may output one or more of a vertical synchronization signal, a horizontal synchronization signal, and a clock signal, but these signals are omitted from the illustration for convenience of explanation.

[0038] The timing control unit (12) receives a data signal (DATA) along with a driving signal including a data enable signal (DE) or a vertical synchronization signal, a horizontal synchronization signal, and a clock signal from the image processing unit (11). Based on the driving signal, the timing control unit (12) outputs a gate timing control signal (GDC) for controlling the operation timing of the scan driving unit (14) and a data timing control signal (DDC) for controlling the operation timing of the data driving unit (13).

[0039] The data driver (13) samples and latches the data signal (DATA) supplied from the timing control unit (12) in response to the data timing control signal (DDC) supplied from the timing control unit (12), converts it into a gamma reference voltage, and outputs it. The data driver (13) outputs the data signal (DATA) through data lines (DL1 to DLn). The data driver (13) can be formed in the form of an IC (Integrated Circuit).

[0040] The scan driver (14) outputs a scan signal in response to a gate timing control signal (GDC) supplied from the timing control unit (12). The scan driver (14) outputs a scan signal through gate lines (GL1 to GLm). The scan driver (14) is formed in the form of an Integrated Circuit (IC) or formed in a Gate In Panel (GIP) manner on a display panel (20).

[0041] The display panel (20) displays an image in response to a data signal (DATA) and a scan signal supplied from a data driving unit (13) and a scan driving unit (14). The display panel (20) includes subpixels (50) that operate to display an image.

[0042] The subpixels (50) include a red subpixel, a green subpixel, and a blue subpixel, or a white subpixel, a red subpixel, a green subpixel, and a blue subpixel. The subpixels (50) may have one or more different light-emitting areas depending on their light-emitting characteristics.

[0043] As shown in FIG. 2, one subpixel includes a switching transistor (30), a driving transistor (35), a capacitor (40), a compensation circuit (45), and an organic light-emitting diode (60).

[0044] The switching transistor (30) switches in response to a scan signal supplied through the first gate line (32) so that a data signal supplied through the first data line (36) is stored as a data voltage in the capacitor (45). The driving transistor (35) operates to allow a driving current to flow between the power line (42) (high potential voltage) and the cathode power line (44) (low potential voltage) according to the data voltage stored in the capacitor (45). The organic light-emitting diode (60) operates to emit light according to the driving current formed by the driving transistor (35).

[0045] The compensation circuit (45) is a circuit added within the subpixel to compensate for the threshold voltage of the driving transistor (35), etc. The compensation circuit (45) is composed of one or more transistors. The configuration of the compensation circuit (45) varies greatly depending on the external compensation method, and an example thereof is described as follows.

[0046] As illustrated in FIG. 3, the compensation circuit (45) includes a sensing transistor (65) and a sensing line (70) (or reference line). The sensing transistor (65) is connected between the source electrode of the driving transistor (35) and the anode electrode of the organic light-emitting diode (60) (hereinafter referred to as the sensing node). The sensing transistor (65) operates to supply an initialization voltage (or sensing voltage) transmitted through the sensing line (70) to the sensing node of the driving transistor (35), or to sense the voltage or current of the sensing node of the driving transistor (35) or the sensing line (70).

[0047] The switching transistor (30) has its first electrode connected to the first data line (36) and its second electrode connected to the gate electrode of the driving transistor (35). The driving transistor (35) has its first electrode connected to the power line (42) and its second electrode connected to the anode electrode of the organic light-emitting diode (60). The capacitor (45) has its first electrode connected to the gate electrode of the driving transistor (35) and its second electrode connected to the anode electrode of the organic light-emitting diode (60). The organic light-emitting diode (60) has its anode electrode connected to the second electrode of the driving transistor (35) and its cathode electrode connected to the second power line (44). The sensing transistor (65) has its first electrode connected to the sensing line (70) and its second electrode connected to the anode electrode of the organic light-emitting diode (60), which is the sensing node, and the second electrode of the driving transistor (35).

[0048] The operating time of the sensing transistor (65) may be similar / identical to or different from that of the switching transistor (30) depending on the external compensation algorithm (or the configuration of the compensation circuit). For example, the switching transistor (30) may have its gate electrode connected to the first gate line (32), and the sensing transistor (65) may have its gate electrode connected to the second gate line (34). In this case, a scan signal (Scan) is transmitted to the first gate line (32), and a sensing signal (Sense) is transmitted to the second gate line (34). As another example, the first gate line (32) connected to the gate electrode of the switching transistor (30) and the second gate line (34) connected to the gate electrode of the sensing transistor (65) may be connected to be shared in common.

[0049] The sensing line (70) can be connected to the data driver. In this case, the data driver can sense the sensing node of the subpixel in real time, during a non-display period of the image, or during a period of N frames (N is an integer greater than or equal to 1) and generate a sensing result. Meanwhile, the switching transistor (30) and the sensing transistor (65) can be turned on at the same time. In this case, the sensing operation through the sensing line (70) and the data output operation that outputs the data signal are separated (distinguished) from each other based on the time division method of the data driver.

[0050] In addition, the compensation target based on the sensing result may be a digital data signal, an analog data signal, or gamma. Furthermore, the compensation circuit that generates a compensation signal (or compensation voltage), etc., based on the sensing result may be implemented inside the data driving unit, inside the timing control unit, or as a separate circuit.

[0051] The light-blocking layer (80) may be placed only below the channel region of the driving transistor (DR), or may be placed below the channel region of the driving transistor (35) as well as below the channel region of the switching transistor (30) and the sensing transistor (65). The light-blocking layer (80) may be used simply for the purpose of blocking external light, or the light-blocking layer (80) may be utilized as an electrode to facilitate connection with other electrodes or lines, or as an electrode constituting a capacitor, etc. Therefore, the light-blocking layer (80) is selected as a metal layer of a multilayer (a multilayer of heterogeneous metals) to have light-blocking properties.

[0052] In addition, although FIG. 3 describes a subpixel of a 3T (Transistor) 1C (Capacitor) structure including a switching transistor (30), a driving transistor (35), a capacitor (40), an organic light-emitting diode (60), and a sensing transistor (65) as an example, it may be configured as 3T2C, 4T2C, 5T1C, 6T2C, etc. when a compensation circuit (45) is added.

[0053] FIG. 4 is a schematic diagram showing the planar layout of a subpixel according to the present invention, and FIG. 5 is a cross-sectional view taken along the cutting line I-I' of FIG. 4.

[0054] Referring to FIG. 4, a first subpixel (82), a second subpixel (84), and a third subpixel (86) are formed on the display area of ​​the substrate. In each of the first subpixel (82), the second subpixel (84), and the third subpixel (86), a circuit is formed that includes an organic light-emitting diode (light-emitting element), a switching transistor (30) for driving the organic light-emitting diode, a sensing transistor (65), and a driving transistor (35). In each of the first subpixel (82), the second subpixel (84), and the third subpixel (86), the organic light-emitting diode emits light in response to the operation of the switching transistor (30), the sensing transistor (65), and the driving transistor (35). Between the first subpixel (82), the second subpixel (84) and the third subpixel (86), a power line (42), a sensing line (70), and first to third data lines (36, 38, 52) are arranged. The first and second gate lines (32, 34) are arranged across the first subpixel (82), the second subpixel (84), and the third subpixel (86).

[0055] Wiring such as the power line (42), the sensing line (70), and the first to third data lines (36, 38, 52), as well as the electrodes constituting the thin-film transistor, are located on different layers but are electrically connected through contact holes (via holes). The sensing line (70) is connected to each sensing transistor (65) of the first subpixel (82), the second subpixel (84), and the third subpixel (86) via the sensing connection line (72). The power line (42) is connected to each driving transistor (35) of the first subpixel (82), the second subpixel (84), and the third subpixel (86) via the power connection line (74). The first and second gate lines (32, 34) are connected to each sensing and switching transistor (65, 30) of the first subpixel (82), the second subpixel (84), and the third subpixel (86).

[0056] The aforementioned first subpixel (82) may be a red subpixel, the second subpixel (84) may be a green subpixel, and the third subpixel (86) may be a blue subpixel. However, the arrangement of each subpixel may be interchanged with one another.

[0057] Referring to FIG. 5, the cross-sectional structure of the first subpixel as an example among the first to third subpixels is as follows.

[0058] Referring to FIG. 5, a light-blocking layer (80) is positioned on a substrate (100). The light-blocking layer (80) serves to prevent photocurrent from occurring in the transistor by blocking external light from being incident. A buffer layer (105) is positioned on the light-blocking layer (80). The buffer layer (105) serves to protect the transistor formed in a subsequent process from impurities, such as alkali ions, that leak out from the light-blocking layer (80). The buffer layer (105) may be silicon oxide (SiOx), silicon nitride (SiNx), or a multilayer thereof.

[0059] A semiconductor layer (110) of a driving transistor (35) is located on a buffer layer (105). The semiconductor layer (110) may be composed of a silicon semiconductor, an oxide semiconductor, or an organic semiconductor. The silicon semiconductor may be formed using amorphous silicon or polycrystalline silicon obtained by crystallizing amorphous silicon. The oxide semiconductor may be composed of any one of zinc oxide (ZnO), indium zinc oxide (InZnO), indium gallium zinc oxide (InGaZnO), or zinc tin oxide (ZnSnO). The organic semiconductor may be composed of low-molecular-weight or high-molecular-weight organic materials such as melocyanine, phthalocyanine, pentacene, and thiophene polymer. The semiconductor layer (110) includes a drain region and a source region containing p-type or n-type impurities, and includes a channel between them.

[0060] A gate insulating film (115) is positioned on a semiconductor layer (110). The gate insulating film (115) may be silicon oxide (SiOx), silicon nitride (SiNx), or a multilayer thereof. A gate electrode (120) is positioned on the gate insulating film (115) at a certain region of the semiconductor layer (110), that is, at a location corresponding to the channel when impurities are injected. The gate electrode (120) is formed from any one selected from the group consisting of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof. Additionally, the gate electrode (GAT) may be a multilayer formed from any one selected from the group consisting of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof. For example, the gate electrode (120) may be a double layer of molybdenum / aluminum-neodymium or molybdenum / aluminum.

[0061] An interlayer insulating film (125) that insulates the gate electrode (120) is located on the gate electrode (120). The interlayer insulating film (125) may be a silicon oxide film (SiOx), a silicon nitride film (SiNx), or a multilayer thereof. A source electrode (130) and a drain electrode (135) are located on the interlayer insulating film (125). The source electrode (130) and the drain electrode (135) are connected to the semiconductor layer (110) through contact holes (137) that respectively expose the source and drain regions of the semiconductor layer (110). The source electrode (130) and the drain electrode (135) may be composed of a single layer or multiple layers. If the source electrode (130) and the drain electrode (135) are single layers, they may be made of any one selected from the group consisting of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof. Additionally, if the source electrode (130) and the drain electrode (135) are multiple layers, they may be composed of a double layer of molybdenum / aluminum-neodymium, titanium / aluminum / titanium, molybdenum / aluminum / molybdenum, or a triple layer of molybdenum / aluminum-neodymium / molybdenum. A first data line (36) is located in an area spaced apart from the driving transistor (35), and a cathode power line (44) is located in another area.

[0062] Accordingly, a driving transistor (35) comprising a semiconductor layer (110), a gate electrode (120), a source electrode (130), and a drain electrode (135) is configured.

[0063] A passivation film (140) is positioned on a substrate (100) that includes a driving transistor (35). The passivation film (140) is an insulating film that protects the lower device and may be a silicon oxide film (SiOx), a silicon nitride film (SiNx), or a multilayer thereof. In a portion of the passivation film (140), a first via hole (142) is positioned to expose the drain electrode (135) of the lower driving transistor (35), and a second via hole (143) is positioned to expose the cathode power line (44).

[0064] An overcoat layer (150) is positioned on the passivation film (140). The overcoat layer (150) may be a flattening film to mitigate the step difference of the underlying structure and is composed of organic materials such as polyimide, benzocyclobutene series resin, and acrylate. In a portion of the overcoat layer (150), a third via hole (152) is positioned to expose the drain electrode (135) by exposing the first via hole (142) of the passivation film (140), and a fourth via hole (154) is positioned to expose the cathode power line (44) by exposing the second via hole (143) of the passivation film (140).

[0065] An organic light-emitting diode (60) is formed on the overcoat layer (150). The organic light-emitting diode (60) includes a first electrode (160) connected to a driving transistor (35), a second electrode (180) facing the first electrode (160), and an organic light-emitting layer (175) interposed between the first electrode (160) and the second electrode (180). The first electrode (160) may be an anode electrode, and the second electrode (180) may be a cathode electrode.

[0066] The first electrode (160) is positioned on the overcoat layer (150) and can be connected to the drain electrode (135) of the driving transistor (35) through the third via hole (152) of the overcoat layer (150) and the first via hole (142) of the passivation film (140). The first electrode (160) may be assigned one per subpixel, but is not limited thereto. The first electrode (160) may function as a transparent electrode by being made of a transparent conductive material such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), or ZnO (Zinc Oxide), corresponding to the adopted light emission method, and may function as a reflective electrode by including a reflective layer. The reflective layer may be made of aluminum (Al), copper (Cu), silver (Ag), nickel (Ni), or an alloy thereof, and preferably may be made of APC (silver / palladium / copper alloy).

[0067] A connection pattern (165) is located on the overcoat layer (150) spaced apart from the first electrode (160), and is connected to the cathode power line (44) through the fourth via hole (154) of the overcoat layer (150) and the second via hole (143) of the passivation film (140). The connection pattern (165) is formed with the same structure as the first electrode (160).

[0068] A bank layer (170) is positioned on a substrate (100) on which a first electrode (160) is formed. The bank layer (170) includes a first bank layer (172) and a second bank layer (176). The first bank layer (172) includes a first opening (173) that exposes the first electrode (160), and the second bank layer (176) includes a second opening (177) that exposes a portion of the first bank layer (172) and the first electrode (160). The second opening (177) is formed with a larger area than the first opening (173) so as to expose a portion of the first bank layer (172).

[0069] Additionally, the first bank layer (172) includes a third opening (174) that exposes a connection pattern (165), and the second bank layer (176) includes a fourth opening (178) that exposes a part of the first bank layer (172) and the connection pattern (165). The fourth opening (178) is formed with a larger area than the third opening (174) so ​​as to expose a part of the first bank layer (172).

[0070] An organic light-emitting layer (175) is disposed on a substrate (100) on which a bank layer (170) is formed. The organic light-emitting layer (175) includes an emission layer (EL) and may further include one or more of a hole injection layer (HIL), a hole transport layer (HTL), an electron transport layer (ETL), and an electron injection layer (EIL). By coating and drying the organic light-emitting layer (175) using a solution process such as inkjet printing or nozzle coating, the upper surface where the organic light-emitting layer (175) and the bank layer (170) come into contact can be formed in a rounded shape.

[0071] The second electrode (180) is disposed on the organic light-emitting layer (175). The second electrode (180) can be formed widely across the front surface of the substrate (100). The second electrode (180) can function as a transmissive electrode or a reflective electrode, corresponding to the adopted light-emitting method. If the second electrode (180) is a transmissive electrode, it may be formed from a transparent conductive material such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide), or may be made of magnesium (Mg), calcium (Ca), aluminum (Al), silver (Ag), or an alloy thereof, having a thickness thin enough to allow light to pass through. The second electrode (180) is connected to the cathode power line (44) by being connected to the connection pattern (165) through the third opening (174) of the first bank layer (172) and the fourth opening (178) of the second bank layer (176).

[0072] Meanwhile, a counter-substrate (190) is positioned opposite to the substrate (100) on which the driving transistor (35) and the organic light-emitting diode (60) are formed. The counter-substrate (190) seals the substrate (100) and includes a color filter (195) at the bottom. The color filter (195) may be a red color filter and functions to make the red color coordinates more intense. For example, if the first subpixel is a red subpixel, the counter-substrate (190) may be equipped with a red color filter in the area corresponding to the first subpixel. Furthermore, no color filter may be provided in the area of ​​the counter-substrate (190) corresponding to the second subpixel, which is a green subpixel, and the third subpixel, which is a blue subpixel. However, the present invention is merely an example, and a color filter of the corresponding color may be provided for each subpixel. The structure illustrated in Fig. 5 can be applied equally to other subpixels as well as the subpixel in question.

[0073] In the following, the organic light-emitting display device according to FIGS. 1 to 5 described above will be explained in more detail.

[0074] <1st Example>

[0075] FIG. 6 is a plan view showing an organic light-emitting display device according to a first embodiment of the present invention, FIG. 7 is a cross-sectional view taken along the dotted line Ⅱ-Ⅱ' of FIG. 6, FIG. 8 is a cross-sectional view taken along the dotted line Ⅲ-Ⅲ' of FIG. 6, FIG. 9 is a cross-sectional view showing thickness non-uniformity of the organic light-emitting layer in a solution process, and FIG. 10 is a cross-sectional view showing defects in an organic light-emitting diode caused by foreign matter.

[0076] Referring to FIGS. 6 and 7, an organic light-emitting display device according to a first embodiment of the present invention includes a substrate (100) on which a plurality of subpixels (50R, 50G, 50B) are arranged. The substrate (100) may have various planar shapes. For example, as shown in the drawings, it may include not only rectangular shapes but also square, circular, elliptical shapes, etc.

[0077] The aforementioned thin-film transistor, capacitor, and organic light-emitting diode are disposed on a substrate (100). The organic light-emitting diode includes a first electrode (160), an organic light-emitting layer (175), and a second electrode (180). Each subpixel (50R, 50G, 50B) has a light-emitting portion defined by a bank layer (170). Since the bank layer (170) is described in detail in FIG. 6, other components are omitted from the illustration.

[0078] Subpixels (50R, 50G, 50B) may be arranged along a first direction (e.g., X-axis direction) and a second direction (e.g., Y-axis direction) that intersect each other. Subpixels arranged adjacently along the first direction may emit light of different colors, and subpixels arranged adjacently along the second direction may emit light of the same color. For example, subpixels arranged in the first direction may have red subpixels (50R), green subpixels (50G), and blue subpixels (50B) arranged repeatedly, and subpixels arranged in the second direction may have red subpixels (50R) arranged in the first column, green subpixels (50G) arranged in the second column, and blue subpixels (50B) arranged in the third column. However, since the present invention describes the arrangement of subpixels as an example, they may be arranged in various ways.

[0079] In each subpixel (50R, 50G, 50B), a first electrode (160) of an organic light-emitting diode is located. A bank layer (170) is disposed on the first electrode (160) to partition a light-emitting region. The bank layer (170) includes a first bank layer (172) and a second bank layer (176).

[0080] The first bank layer (172) is positioned on the first electrode (160) and is arranged to cover the edge of the first electrode (160). The first bank layer (172) includes a first opening (173) that exposes at least a portion of the first electrode (160). One first opening (173) exposes one first electrode (160). Thus, the first opening (173) can correspond one-to-one with the first electrode (160).

[0081] The first bank layer (172) may be formed with a relatively thin thickness so that it can be covered by an organic light-emitting layer formed on top. The first bank layer (172) may have hydrophilicity and may be formed of a hydrophilic inorganic material such as silicon oxide (SiOx) or silicon nitride (SiNx), for example.

[0082] In FIG. 6, the first opening (173) is illustrated as having an approximately rectangular shape, but is not limited thereto. Also, the first openings (173) are illustrated as having the same shape and area, but are not limited thereto, and at least one first opening (173) may have a different shape and / or area from another first opening (173). For example, the shape and / or area of ​​the first opening (173) may be appropriately selected considering the lifespan of the organic light-emitting material for forming the organic light-emitting layer of the organic light-emitting diode. The portion of the first electrode (160) exposed by the first opening (173) may be defined as a light-emitting portion.

[0083] A second bank layer (176) is positioned on a substrate (100) on which a first bank layer (172) is formed. The second bank layer (176) is positioned between subpixels that emit different colors among the subpixels. The second bank layer (176) includes a second opening (177) that exposes at least a portion of the first electrode (160). A plurality of second openings (177) are arranged parallel to each other in a first direction and each extend in a second direction. The second opening (177) extends in the second direction to expose the first electrodes (160) of each subpixel arranged along the second direction. Additionally, the second opening (177) extends in the second direction to expose a plurality of first openings (173) arranged along the second direction.

[0084] The second bank layer (176) may have hydrophobicity. For example, the second bank layer (176) may be formed by coating a hydrophobic material onto an insulating film or by forming a hydrophobic material. The second bank layer (176) may be made of an organic material. The hydrophobicity of the second bank layer (176) may function to push the organic light-emitting material constituting the organic light-emitting layer toward the center of the light-emitting region. Additionally, the second bank layer (176) may function as a barrier to confine the organic light-emitting material deposited in the area, thereby preventing organic light-emitting materials of different colors from mixing with each other.

[0085] In FIG. 6, the second opening (177) is illustrated as having a bar shape, but is not limited thereto. Also, the second openings (177) are illustrated as having the same shape and area, but are not limited thereto, and at least one second opening (177) may have a different shape and / or area from the other second opening (177). For example, the shape and / or area of ​​the second opening (177) can be appropriately selected considering the lifespan of the organic light-emitting material.

[0086] The second opening (177) is positioned spaced apart from the first opening (173). That is, the boundary of the first bank layer (172) is spaced apart from the boundary of the second bank layer (176) by a set distance. Accordingly, the first opening (173) can be exposed by the second opening (177), and the first bank layer (172) can be exposed by the second opening (177).

[0087] With reference to FIGS. 7 and 8, the structure of the first electrode, bank layer, organic light-emitting layer, and second electrode will be examined. In FIGS. 7 and 8, the structure below the overcoat layer (150) is omitted, and the structure of the first electrode, bank layer, organic light-emitting layer, and second electrode will be examined in detail. The omitted structure below the overcoat layer (150) is the semiconductor layer (110), gate electrode (120), source electrode (130), and drain electrode (135) of the driving transistor (35) placed below the first electrode (160) in FIG. 5 described above. Additionally, the light-blocking layer (80) placed below the driving transistor (35) and the cathode power line (44) placed in a region spaced apart from the driving transistor (35) have been omitted.

[0088] First electrodes (160) of each subpixel are placed on the overcoat layer (150), and the edges of the first electrodes (160) are covered by the first bank layer (172), with a portion exposed. A second bank layer (176) is located on the first bank layer (172).

[0089] An organic light-emitting layer (175) is positioned on a substrate on which a second bank layer (176) is formed. The organic light-emitting layer (175) may be formed within a second opening (177) of the second bank layer (176) along the extension direction of the second opening (177). That is, an organic light-emitting material dropped into one second opening (177) covers the first electrodes (160) and the first bank layer (172) exposed by the second opening (177). The organic light-emitting material completely covers the first bank layer (172) so as not to be separated by the first bank layer (172), but is separated by the second bank layer (176).

[0090] An organic light-emitting material of the same color is deposited on a plurality of first electrodes (160) exposed by a single second opening (177). This means that light of the same color is emitted from a plurality of subpixels assigned to a position corresponding to the single second opening (177). The planar shape of the organic light-emitting layer (175) corresponds to the planar shape of the second opening (177) and may be formed, for example, in a bar shape.

[0091] Organic light-emitting materials of different colors may be sequentially and alternately dropped into each of the corresponding second openings (177). The organic light-emitting materials of different colors may be organic light-emitting materials that emit red (R), green (G), and blue (B).

[0092] The second bank layer (176) is positioned between the first electrodes (160) adjacent in the first direction (x-axis direction in FIG. 6) so that organic light-emitting materials of different colors, each dropped into the second openings (177) adjacent in the first direction, do not mix with each other. That is, organic light-emitting materials of different colors, each dropped into the different second openings (177), are physically separated by the second bank layer (176).

[0093] The organic light-emitting material used to form the organic light-emitting layer (175) during the solution process is dropped to cover at least a portion of the first electrode (160), a portion of the first bank layer (172), and a portion of the second bank layer (176). The first bank layer (172) is made of a hydrophilic thin film provided to prevent poor wettability due to the hydrophobic characteristics of the first electrode (160), and can induce the hydrophilic organic light-emitting material to spread well. The second bank layer (176) is a hydrophobic thick film that allows the hydrophilic organic light-emitting material to be pushed toward the center. Due to the structure of the first bank layer (172) and the second bank layer (176), the organic light-emitting layer (175) can be formed with a relatively uniform thickness over the light-emitting region.

[0094] In the present invention, a plurality of subpixels emitting the same color may be allocated within a single second opening (177). If each of the second openings (177) exposes a single subpixel, the thickness of the organic light-emitting material deposited on each of the second openings (177) may differ depending on the equipment deviation during the solution process. The equipment deviation may refer to a deviation in the discharge amount between the nozzles of the inkjet equipment. That is, the discharge amount of each nozzle used to deposit the organic light-emitting material on the second openings (177) may not be constant. In this case, the thickness of the organic light-emitting material deposited on each of the subpixels through the nozzles allocated per subpixel may differ depending on the location.

[0095] Accordingly, in the present invention, a plurality of subpixels emitting the same color can be allocated within a single second opening (177), and a plurality of nozzles corresponding to the number of subpixels can be allocated, so that the variation in discharge amount between nozzles is compensated, and the thickness between the organic light-emitting materials deposited in the second openings (177) can be made uniform.

[0096] Accordingly, the organic light-emitting display device according to the present invention can prevent a decrease in the thickness uniformity of the organic light-emitting layer (175), thereby preventing a decrease in display quality caused by thickness variation within the subpixel. In addition, by ensuring the uniformity of the organic light-emitting layer (175), defects such as a decrease in the lifespan of the device or the occurrence of dark spots can be prevented.

[0097] The pre-set distance between the boundary of the first bank layer (172) and the boundary of the second bank layer (176) described above represents the minimum distance that can secure thickness uniformity of the organic light-emitting layer (175). If the boundary of the first bank layer (172) and the boundary of the second bank layer (176) are located closer than the pre-set distance, the uniformity of the organic light-emitting layer (175) cannot be secured, and if the boundary of the first bank layer (172) and the boundary of the second bank layer (176) are located farther than the pre-set distance, the area of ​​the first electrode (160) shielded by the first bank layer (172) increases, and a problem may occur in which the aperture ratio decreases.

[0098] In the organic light-emitting display device according to the present invention, since the second opening (177) of the second bank layer (176) extends along the second direction, the second bank layer (177) is not located between the subpixels arranged in the second direction. Therefore, in the present invention, since the aforementioned positional constraint of the first bank layer (172) is relatively reduced, not only can the degree of design freedom be improved, but a wide light-emitting area on the first electrode (160) can also be secured. Accordingly, the present invention can provide an organic light-emitting display device that secures a sufficient aperture ratio while improving the degree of design freedom.

[0099] In addition, as the resolution increases, the area of ​​the subpixels arranged in the display device decreases relatively. In this case, as the organic light-emitting material is not deposited in the correct position, a color mixing defect may occur in which organic light-emitting layers (175) of different colors are mixed with each other. The present invention can improve the color mixing defect because it can sufficiently secure the deposit area of ​​the organic light-emitting material on the wide second opening (177) corresponding to a plurality of subpixels.

[0100] Meanwhile, referring to FIG. 9, when an organic light-emitting layer (175) is formed using a solution process, a pile-up phenomenon may occur, which may degrade the light-emitting characteristics of the organic light-emitting display device.

[0101] Specifically, an organic light-emitting material is dropped onto a first electrode (160) partitioned by a bank layer (170) through an inkjet device or the like. During the curing process, the dropped organic light-emitting material has a thickness variation depending on the position due to differences in curing speed and lower step. That is, an uneven film is formed where the edge portion (A) in contact with the bank layer (170) is thick and the central portion (M) is thin.

[0102] As such, if the organic light-emitting layer (175) is formed unevenly, a problem may arise where the display quality deteriorates due to a variation in brightness depending on the location. In addition, a problem may arise where the lifespan of the device is reduced due to a difference in current density within the organic light-emitting layer (175), or where dark spots occur, leading to a decrease in process yield. Considering this, when forming the light-emitting layer using a solution process, it is necessary to minimize the area where the pile-up phenomenon occurs.

[0103] Additionally, referring to FIG. 10, as described in FIG. 5, the first electrode (160) is connected to the drain electrode (DE) through the first via hole (142) of the passivation film (140) that exposes the drain electrode (135) and the third via hole (153) of the overcoat layer (150). Due to the step difference between the first via hole (142) and the third via hole (153), the first bank layer (172) formed on the first electrode (160) is formed with a thin thickness at the step portion of the first electrode (160). When a foreign substance (99) is present on the adjacent first electrode (160), the organic light-emitting material deposited on the first electrode (160) is pushed toward the foreign substance (99), so the area around the foreign substance (99) is formed relatively thickly and the other area is formed relatively thinly. As a result, a defect may occur in which the stepped portion of the first electrode (160) is exposed to the upper part of the first bank layer (172) and the organic light-emitting layer (175) and shorts (98) with the second electrode (180). Therefore, a dark spot may occur due to the short circuit between the first electrode (160) and the second electrode (180).

[0104] To prevent this, in the first embodiment of the present invention, the thickness of the first bank layer (172) formed on the third via hole (153) of the overcoat layer (150) where the first electrode (160) and the drain electrode (135) of the driving transistor are connected can be formed thickly.

[0105] FIG. 11 is a plan view showing an organic light-emitting display device according to a first embodiment of the present invention, FIG. 12 is a cross-sectional view taken along the dotted line Ⅳ-Ⅳ' of FIG. 11, and FIG. 13 is a cross-sectional view taken along the dotted line Ⅴ-Ⅴ' of FIG. 11.

[0106] Referring to FIG. 11, each subpixel (50R, 50G, 50B) includes a light-emitting region (200) defined by a first bank layer (172). The first bank layer (172) may include a region with a relatively thick thickness.

[0107] Specifically, the first bank layer (172) may include a first region (210) with a relatively thick thickness and a second region (220) with a thinner thickness than the first region (210). The first region (210) may be defined as a region extending in the first direction (x-axis direction) and positioned between the light-emitting regions (200) of subpixels (50R, 50R, 50R) arranged in the second direction (y-axis direction). In FIG. 11, the first direction may be the direction in which the short side of the subpixels (50R, 50G, 50B) is extended, and the first region (210) extends parallel to the direction in which the short side of the subpixels (50R, 50G, 50B) is extended. The first bank layer (172) is positioned in the region excluding the light-emitting regions (200) of each subpixel (50R, 50G, 50B). Among the first bank layer (172), the first region (210) may be a region disposed between the light-emitting regions (200) of subpixels (50R, 50R, 50R, or 50G, 50G, 50G, or 50B, 50B, 50B) arranged in the second direction. In other words, the first region (210) of the first bank layer (172) may be a region disposed between subpixels emitting the same color.

[0108] The second region (220) may be defined as a region extending in the second direction, positioned between the light-emitting regions (200) of subpixels (50R, 50G, 50B) arranged in the first direction. The second region (220) may be a region positioned between subpixels emitting different colors. The second region (220) may be the remaining region excluding the first region (210).

[0109] The first region (210) intersects the length direction (y-axis direction) of the second region (220) and disconnects the second region (220). Accordingly, the first region (210) is formed in a bar shape that extends continuously from one side of the substrate to the other, whereas the second region (220) is spaced apart from each other with the first region (210) in between. Additionally, the first region (210) intersects the second bank layer (176) and is positioned overlapping the second bank layer (176). The second region (220) is not positioned overlapping the first region (210) and is positioned overlapping the second bank layer (176).

[0110] The first region (210) of the first bank layer (172) overlaps with the third via hole (153) to which the first electrode (160) and the drain electrode (135) are connected.

[0111] Specifically, referring to FIG. 12, a passivation film (140) is disposed on the drain electrode (135) of a driving transistor and is provided with a first via hole (142) that exposes the drain electrode (135). An overcoat layer (150) is disposed on the passivation film (140) and is provided with a third via hole (153) that exposes the drain electrode (135). A first electrode (160) is disposed on the overcoat layer (150) and is connected to the drain electrode (135) through the first and third via holes (142, 153). A first bank layer (172) is disposed having a first opening (173) that exposes the first electrode (160) on the first electrode (160), and a second bank layer (176) is disposed having a second opening (177) that exposes the first opening (173) on the first bank layer (172). An organic light-emitting layer (175) is disposed within the second opening (177), and a second electrode (180) is disposed on the second bank layer (176) and the organic light-emitting layer (175).

[0112] The first region (210) of the first bank layer (172) overlaps with the third via hole (153) and has a first thickness (T1) so as to completely cover the upper part of the third via hole (153). As described in FIG. 10, since the third via hole (153) region has a large step difference, if the first thickness (T1) of the first region (210) overlapping with the third via hole (153) is sufficiently thick, the step difference of the third via hole (153) can be mitigated. Therefore, by forming the thickness of the first region (210) of the first bank layer (172) thickly, the first electrode (160) formed in the third via hole (153) can be prevented from being exposed to the upper part of the first bank layer (172). In addition, even when foreign matter (99) is present, the first region (210) of the first bank layer (172) with a thick thickness can suppress the flow of organic light-emitting material, thereby preventing the thickness from becoming uneven.

[0113] Additionally, the second region (220) of the first bank layer (172) has a second thickness (T2) that is thinner than the first thickness (T1). The second region (220) is an area that overlaps with the second bank layer (176), and as described in FIG. 9 above, the thickness of the organic light-emitting layer may be formed unevenly due to the thickness of the first bank layer (172). Therefore, the second region (220) of the first bank layer (172) can be formed with the thinnest possible thickness.

[0114] The first region (210) and the second region (220) of the first bank layer (172) can be formed with different thicknesses for the first region (210) and the second region (220) using a half-tone mask after the first bank layer material is formed on the substrate.

[0115] As illustrated in FIG. 13, if the thickness of the second region (220) of the first bank layer (172) is made thin, the step difference between the first electrode (160) and the first bank layer (172) is reduced, thereby allowing the thickness of the organic light-emitting layer (175) to be formed uniformly. That is, a film with uniform thickness can be formed at the edge and central portions of the organic light-emitting layer (175) in contact with the bank layer (170).

[0116] Accordingly, by forming the organic light-emitting layer (175) uniformly, the brightness variation according to position can be reduced, thereby improving the display quality. In addition, by reducing the difference in current density within the organic light-emitting layer (175), the lifespan of the device can be reduced and the occurrence of dark spots can be prevented, thereby improving the process yield.

[0117] <2nd Example>

[0118] FIG. 14 is a plan view showing an organic light-emitting display device according to a second embodiment of the present invention, and FIG. 15 is a cross-sectional view taken along the cut line VI-VI' of FIG. 14.

[0119] Referring to FIG. 14, each subpixel (50R, 50G, 50B) includes a light-emitting region (200) defined by a first bank layer (172). The first bank layer (172) may include a region with a relatively thin thickness.

[0120] Specifically, the first bank layer (172) may include a first region (210) with a relatively thick thickness and a second region (220) with a thinner thickness than the first region (210). The first region (210) may be defined as a region placed between the light-emitting regions (200) of subpixels (50R, 50R, 50R) arranged in the second direction (y-axis direction). The first bank layer (172) is placed in a region excluding the light-emitting regions (200) of each subpixel (50R, 50G, 50B). Among the first bank layer (172), the first region (210) may be a region placed between the light-emitting regions (200) of subpixels (50R, 50R, 50R, or 50G, 50G, 50G, or 50B, 50B, 50B) arranged in the second direction. In other words, the first region (210) of the first bank layer (172) may be a region placed between subpixels that emit the same color.

[0121] The second region (220) may be defined as a region extending in the second direction, positioned between the light-emitting regions (200) of the subpixels (50R, 50G, 50B) arranged in the first direction. That is, the second region (220) is positioned to extend parallel to the direction in which the long side of the plurality of subpixels (50R, 50G, 50B) is extended. Additionally, the second region (220) may be a region positioned between subpixels emitting different colors. The second region (220) may be the remaining region excluding the first region (210).

[0122] Unlike the first embodiment described above, in the second embodiment, the first region (210) may be spaced apart from each other and the second region (220) may be continuously extended. Specifically, the second region (220) intersects the length direction (x-axis direction) of the first region (210) and cuts off the first region (210). Accordingly, the second region (220) is formed in a bar shape that is continuously extended from one side of the substrate to the other, whereas the first region (210) is spaced apart from each other with the second region (220) in between. Additionally, the second region (220) is arranged parallel to the second bank layer (176) and overlaps with the second bank layer (176). The first region (210) does not overlap with the second region (220) and does not overlap with the second bank layer (176).

[0123] The first region (210) of the first bank layer (172) overlaps with the third via hole (153) to which the first electrode (160) and the drain electrode (135) are connected.

[0124] Specifically, referring to FIG. 15, the first region (210) of the first bank layer (172) overlaps with the third via hole (153) and has a first thickness (T1) so as to completely cover the upper part of the third via hole (153). Since the third via hole (153) region has a large step difference, if the first thickness (T1) of the first region (210) overlapping with the third via hole (153) is sufficiently thick, the step difference of the third via hole (153) can be mitigated. Accordingly, by forming the thickness of the first region (210) of the first bank layer (172) thickly, the first electrode (160) formed in the third via hole (153) can be prevented from being exposed to the upper part of the first bank layer (172).

[0125] Additionally, the second region (220) of the first bank layer (172) has a second thickness (T2) that is thinner than the first thickness (T1). The second region (220) is an area that overlaps with the second bank layer (176), and the thickness of the organic light-emitting layer may be formed unevenly due to the thickness of the first bank layer (172). Therefore, the second region (220) of the first bank layer (172) can be formed with the thinnest possible thickness.

[0126] If the thickness of the second region (220) of the first bank layer (172) is made thin, the step difference between the first electrode (160) and the first bank layer (172) is reduced, thereby allowing the thickness of the organic light-emitting layer (175) to be formed uniformly. That is, a film with a uniform thickness can be formed at the edge and central portions of the organic light-emitting layer (175) in contact with the bank layer (170). Therefore, by forming the organic light-emitting layer (175) uniformly, the brightness variation according to position can be reduced, thereby improving the display quality. In addition, by reducing the difference in current density inside the organic light-emitting layer (175), the lifespan of the device can be prevented and the occurrence of dark spots can be prevented, thereby improving the process yield.

[0127] <3rd Example>

[0128] FIG. 16 is a plan view showing an organic light-emitting display device according to a third embodiment of the present invention, and FIG. 17 is a cross-sectional view taken along the cut line Ⅶ-Ⅶ' of FIG. 16.

[0129] Referring to FIG. 16, each subpixel (50R, 50G, 50B) includes a light-emitting region (200) defined by a first bank layer (172). The first bank layer (172) may include a region with a relatively thin thickness.

[0130] Specifically, the first bank layer (172) may include a first region (210) with a relatively thick thickness and a second region (220) with a thinner thickness than the first region (210). The first region (210) is positioned between the light-emitting regions (200) of subpixels (50R, 50R, 50R) arranged in the second direction (y-axis direction). The first region (210) may be a region positioned between subpixels emitting the same color. The first region (210) may be defined as a region overlapping with the third via hole (153) of the overcoat layer. That is, the first bank layer (172) is formed in an area excluding the light-emitting region (200) of each subpixel (50R, 50G, 50B), and the first region (210) among these may be an area that overlaps with the third via hole (153) of each subpixel (50R, 50G, 50B).

[0131] The second region (220) may be defined as the remaining area excluding the light-emitting region (200) of each subpixel (50R, 50G, 50B) and the third via hole (153). The second region (220) may be placed between each of the multiple subpixels (50R, 50G, 50B). For example, the second region (220) may be placed between subpixels emitting the same color and between subpixels emitting different colors. The second region (220) may be the remaining area excluding the first region (210).

[0132] Unlike the first and second embodiments described above, in the third embodiment, the first region (210) may be formed in a dot shape that overlaps with the third via hole (153). Accordingly, the second region (220) is formed in a mesh shape. The first region (210) is spaced apart from the second region (220) in between. For example, the first region (210) may be arranged in a dot shape. Additionally, the second region (220) is arranged to overlap with the second bank layer (176), and the first region (210) is not overlapped with the second bank layer (176).

[0133] The first region (210) of the first bank layer (172) overlaps with the third via hole (153) to which the first electrode (160) and the drain electrode are connected.

[0134] Specifically, referring to FIG. 17, the first region (210) of the first bank layer (172) overlaps with the third via hole (153) and has a first thickness (T1) so as to completely cover the upper part of the third via hole (153). Since the third via hole (153) region has a large step difference, if the first thickness (T1) of the first region (210) overlapping with the third via hole (153) is sufficiently thick, the step difference of the third via hole (153) can be mitigated. Accordingly, by forming the thickness of the first region (210) of the first bank layer (172) thickly, the first electrode (160) formed in the third via hole (153) can be prevented from being exposed to the upper part of the first bank layer (172).

[0135] Additionally, the second region (220) of the first bank layer (172) has a second thickness (T2) that is thinner than the first thickness (T1). The second region (220) is an area that overlaps with the second bank layer (176), and the thickness of the organic light-emitting layer may be formed unevenly due to the thickness of the first bank layer (172). Therefore, the second region (220) of the first bank layer (172) can be formed with the thinnest possible thickness.

[0136] If the thickness of the second region (220) of the first bank layer (172) is made thin, the step difference between the first electrode (160) and the first bank layer (172) is reduced, thereby allowing the thickness of the organic light-emitting layer (175) to be formed uniformly. That is, a film with a uniform thickness can be formed at the edge and central portions of the organic light-emitting layer (175) in contact with the bank layer (170). Therefore, by forming the organic light-emitting layer (175) uniformly, the brightness variation according to position can be reduced, thereby improving the display quality. In addition, by reducing the difference in current density inside the organic light-emitting layer (175), the lifespan of the device can be prevented and the occurrence of dark spots can be prevented, thereby improving the process yield.

[0137] From the above description, those skilled in the art will understand that various changes and modifications are possible within the scope of the technical concept of this specification. Accordingly, the technical scope of this specification should not be limited to the contents described in the detailed description of the specification, but should be determined by the claims. Explanation of the symbols

[0138] 100 : Substrate 170 : Bank layer 172: 1st Bank Layer 176: 2nd Bank Layer 210: Area 1 220: Area 2 160: First electrode 175: Organic light-emitting layer 180: Second electrode

Claims

Claim 1 A substrate having a plurality of subpixels arranged thereon; at least one thin-film transistor disposed on each of the plurality of subpixels; an overcoat layer disposed on the thin-film transistor; a first electrode of an organic light-emitting diode disposed on the overcoat layer and connected to the thin-film transistor; and a first bank layer exposing the first electrode. An organic light-emitting display device comprising: a first bank layer disposed thereon and exposing the first bank layer and the first electrode; wherein the first bank layer comprises a first region extending in a first direction including a region overlapping with a via hole connected to the thin-film transistor and the first electrode, and a second region extending in a second direction intersecting the first direction and excluding the first region, wherein the thickness of the region in the first region that does not overlap with the first electrode is thicker than the thickness of the region in the second region that does not overlap with the first electrode, and the first region overlaps with the via hole and has a thickness covering the upper part of the via hole, wherein the first bank layer is disposed on the overcoat layer in the second region, and the second bank layer is disposed on the first bank layer. Claim 2 In claim 1, the second bank layer is an organic light-emitting display device disposed between subpixels emitting different colors among the plurality of subpixels. Claim 3 In claim 1, the first region is an organic light-emitting display device disposed between subpixels emitting the same color among the plurality of subpixels. Claim 4 In claim 1, the first region and the second region are non-overlapping organic light-emitting display devices. Claim 5 In claim 1, the second region is an organic light-emitting display device that overlaps with the second bank layer. Claim 6 An organic light-emitting display device according to any one of claims 1 to 5, wherein the first region is arranged to extend parallel to the direction in which the short side of the plurality of subpixels is extended. Claim 7 In claim 6, the organic light-emitting display device wherein the first region intersects and overlaps with the second bank layer. Claim 8 In claim 7, the second region is an organic light-emitting display device spaced apart from the first region. Claim 9 An organic light-emitting display device according to claim 1, wherein the second region is arranged to extend parallel to the direction in which the long side of the plurality of subpixels is extended. Claim 10 In claim 9, the organic light-emitting display device wherein the second region is arranged parallel to and overlaps with the second bank layer and is arranged continuously. Claim 11 delete Claim 12 In claim 9, the first region is an organic light-emitting display device spaced apart from each other with the second region in between. Claim 13 In claim 9, the organic light-emitting display device wherein the first region does not overlap with the second bank layer. Claim 14 An organic light-emitting display device according to claim 1, wherein the via hole comprises: a first via hole of a passivation film exposing either the source or drain electrode of the thin-film transistor; and a second via hole of an overcoat layer disposed on the passivation film and exposing the first via hole. Claim 15 An organic light-emitting display device according to claim 1, wherein the first bank layer is hydrophilic and the second bank layer is hydrophobic. Claim 16 delete

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