Display device and manufacturing method thereof

Abstract

The embodiments relate to a display device and a method for manufacturing the same, comprising: a substrate including a light-emitting region and an auxiliary electrode contact portion; an auxiliary electrode disposed in the auxiliary electrode contact portion and having an electrode hole formed therein; a transparent conductive layer covering the auxiliary electrode and having a groove formed above the electrode hole; a bank exposing the area around the groove of the transparent conductive layer and covering the remaining area; an organic layer formed on the bank and the exposed transparent conductive layer; and a cathode electrode formed on the organic layer.

Description

Technology Field

[0001] The present invention relates to a display device and a method for manufacturing the same. Background Technology

[0002] As the information society advances, various types of display devices are being developed. Recently, various display devices such as Liquid Crystal Displays (LCDs), Plasma Display Panels (PDPs), and Organic Light Emitting Displays (OLEDs) are being utilized.

[0003] The organic light-emitting diodes constituting the organic light-emitting display are self-emissive and do not require a separate light source, which allows for a reduction in the thickness and weight of the display. Furthermore, organic light-emitting displays exhibit high-quality characteristics such as low power consumption, high brightness, and high response speed. The problem to be solved

[0004] The embodiments provide a display device and a method for manufacturing the same, which directly contacts a cathode electrode and an auxiliary electrode through a patterned auxiliary electrode structure. means of solving the problem

[0005] A display device according to one embodiment may include a substrate including a light-emitting region and an auxiliary electrode contact portion, an auxiliary electrode disposed in the auxiliary electrode contact portion and having an electrode hole formed therein, a transparent conductive layer covering the auxiliary electrode and having a groove formed above the electrode hole, a bank exposing the area around the groove of the transparent conductive layer and covering the remaining area, an organic layer formed on the bank and the exposed transparent conductive layer, and a cathode electrode formed on the organic layer.

[0006] The above cathode electrode can be directly contacted on the inner surface of the groove.

[0007] The organic layer is disconnected around the groove portion, exposing the inner surface of the groove portion, and the cathode electrode can be in direct contact with the exposed inner surface of the groove portion.

[0008] The transparent conductive layer can cover the auxiliary electrode as a whole and be formed with an area larger than that of the auxiliary electrode.

[0009] The above auxiliary electrode has a structure in which a first transparent conductive layer, a reflective layer, and a second transparent conductive layer are laminated, and the reflective layer is exposed on the inner surface of the electrode hole and can be covered by the transparent conductive layer.

[0010] The above reflective layer may be recessed further from the inner surface of the electrode hole than the first and second conductive layers.

[0011] The above-mentioned reflective layer has a side profile that is inversely tapered, and the groove portion of the above-mentioned transparent conductive layer may be inversely tapered following the shape of the above-mentioned reflective layer.

[0012] The reflective layer is tapered on the side, and the groove portion of the transparent conductive layer may be tapered along the shape of the reflective layer.

[0013] The above auxiliary electrode has a structure in which a first transparent conductive layer and a reflective layer are laminated, and the exposed reflective layer can be entirely covered by the transparent conductive layer.

[0014] The above auxiliary electrode has a structure in which a first transparent conductive layer and a reflective layer are laminated, and the exposed reflective layer can be entirely covered by the transparent conductive layer.

[0015] The above auxiliary electrode has a structure in which a first transparent conductive layer is laminated, and the first transparent conductive layer can be covered as a whole by the transparent conductive layer.

[0016] A method for manufacturing a display device according to one embodiment may include the steps of: forming an auxiliary electrode in an auxiliary electrode contact portion of a substrate including a light-emitting region and an auxiliary electrode contact portion; forming a transparent conductive layer covering the auxiliary electrode; exposing at least one portion of the transparent conductive layer and forming a bank covering the remaining portion; forming an organic layer on the bank and the exposed transparent conductive layer; and forming a cathode electrode on the organic layer.

[0017] The transparent conductive layer can cover the auxiliary electrode as a whole and be formed with an area larger than that of the auxiliary electrode.

[0018] The step of forming the auxiliary electrode includes the step of stacking a first transparent conductive layer, a reflective layer, and a second transparent conductive layer, and the step of forming an electrode hole by performing an etching process while applying a mask, wherein the reflective layer may be exposed on the inner surface of the electrode hole and covered by the transparent conductive layer.

[0019] The reflective layer may be over-etched compared to the first and second transparent conductive layers during the etching process.

[0020] The step of forming the bank may include the step of forming an insulating layer, the step of forming the bank by performing an etching process with a mask applied, and the step of removing the mask by performing an ashing process.

[0021] The above organic layer and the above cathode electrode can be widely formed on the substrate through evaporation deposition or physical vapor deposition. Effects of the invention

[0022] The display device and the method of manufacturing the same according to the embodiments prevent particles from being generated on the side of the electrode hole when ashing the bank for auxiliary electrode contact by covering the side of the electrode hole patterned on the auxiliary electrode with a transparent conductive layer. Accordingly, the display device and the method of manufacturing the same according to the embodiments can solve the problem of particles being visible as dark spots in the auxiliary electrode contact portion.

[0023] In addition, the display device and the method of manufacturing the same according to the embodiments can improve auxiliary electrode contact efficiency by increasing the tip length of the auxiliary electrode.

[0024] The display device and the method of manufacturing the same according to the embodiments can facilitate contact between the cathode electrode and the auxiliary electrode and reduce the resistance between the cathode electrode and the auxiliary electrode. Brief explanation of the drawing

[0025] FIG. 1 is a block diagram showing the configuration of a display device according to one embodiment. Figure 2 is a circuit diagram showing an example of a pixel illustrated in Figure 1. FIG. 3 is a cross-sectional view of a display panel according to one embodiment. FIG. 4 is a cross-sectional view showing an auxiliary electrode contact portion according to the first embodiment. FIG. 5 is a cross-sectional view showing an auxiliary electrode contact portion according to a second embodiment. FIG. 6 is a cross-sectional view showing an auxiliary electrode contact portion according to a third embodiment. FIG. 7 is a cross-sectional view showing an auxiliary electrode contact portion according to a fourth embodiment. FIG. 8 is a cross-sectional view showing an auxiliary electrode contact portion according to the fifth embodiment. FIG. 9 is a cross-sectional view showing an auxiliary electrode contact portion according to the 6th embodiment. FIGS. 10 to 16 are drawings illustrating a method for manufacturing a display device according to one embodiment. Specific details for implementing the invention

[0026] Various embodiments are described below with reference to the drawings. In this specification, where a component (or region, layer, part, etc.) is described as being "on," "connected," "contacted," or "joined" to another component, it means that it may be directly connected / joined to the other component or that a third component may be placed between them.

[0027] Identical reference numerals denote identical components. Additionally, in the drawings, the thicknesses, proportions, and dimensions of the components are exaggerated for the effective illustration of the technical content. "And / or" includes all of one or more combinations that the associated components may define.

[0028] Terms such as "first," "second," etc., may be used to describe various components, but said components are not limited by said terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the various embodiments, the first component may be named the second component, and similarly, the second component may be named the first component. A singular expression includes a plural expression unless the context clearly indicates otherwise.

[0029] Terms such as "below," "lower side," "above," and "upper side" are used to describe the relationships between the components depicted in the drawings. These terms are relative concepts and are described based on the directions indicated in the drawings.

[0030] Terms such as "include" or "have" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0032] FIG. 1 is a block diagram showing the configuration of a display device according to one embodiment.

[0033] Referring to FIG. 1, the display device (1) includes a timing control unit (10), a gate driving unit (20), a data driving unit (30), a power supply unit (40), and a display panel (50).

[0034] The timing control unit (10) can receive an image signal (RGB) and a control signal (CS) from the outside. The image signal (RGB) may include multiple grayscale data. The control signal (CS) may include, for example, a horizontal synchronization signal, a vertical synchronization signal, and a main clock signal.

[0035] The timing control unit (10) can process the image signal (RGB) and the control signal (CS) to suit the operating conditions of the display panel (50) and generate and output image data (DATA), a gate driving control signal (CONT1), a data driving control signal (CONT2), and a power supply control signal (CONT3).

[0036] The gate driver (20) can generate gate signals based on a gate driving control signal (CONT1) output from the timing control unit (10). The gate driver (20) can provide the generated gate signals to pixels (PX) through a plurality of first gate lines (GL11~GL1n). The gate driver (20) can provide a sensing signal to pixels (PX) through a plurality of second gate lines (GL21~GL2n). The sensing signal can be supplied to measure the characteristics of a driving transistor and / or a light-emitting element provided inside the pixels (PX).

[0037] The data driving unit (30) can generate data signals based on image data (DATA) output from the timing control unit (10) and a data driving control signal (CONT2). The data driving unit (30) can provide the generated data signals to pixels (PX) through a plurality of data lines (DL1~DLm). The data driving unit (30) can provide a reference voltage (or sensing voltage, initialization voltage) to pixels (PX) through a plurality of sensing lines (SL1~SLm) or sense the state of pixels (PX) based on electrical signals fed back from pixels (PX).

[0038] The power supply unit (40) can generate a high-potential driving voltage (ELVDD) and a low-potential driving voltage (ELVSS) to be supplied to the display panel (50) based on a power supply control signal (CONT3). The power supply unit (40) can supply the generated driving voltages (ELVDD, ELVSS) to the pixels (PX) through corresponding power lines (PL1, PL2).

[0039] A plurality of pixels (PX) (or, referred to as sub-pixels) are arranged in the display panel (50). The pixels (PX) may be arranged in a matrix form, for example, on the display panel (50). The pixels (PX) may emit light with a brightness corresponding to the gate signal and data signal supplied through the first gate lines (GL11~GL1n) and data lines (DL1~DLm).

[0040] In one embodiment, each pixel (PX) may display any one of red, green, and blue. In another embodiment, each pixel (PX) may display any one of cyan, magenta, and yellow. In various embodiments, each pixel (PX) may display any one of red, green, blue, and white.

[0041] The timing control unit (10), gate driver (20), data driver (30), and power supply unit (40) may each be composed of separate integrated circuits (ICs) or at least partially integrated circuits. Additionally, at least one of the gate driver (20) and the data driver (30) may be configured in an in-panel manner, formed integrally with the display panel (50).

[0043] FIG. 2 is a circuit diagram showing an example of a pixel illustrated in FIG. 1. FIG. 2 illustrates a pixel (PXij) connected to the i-th first gate line (GL1i) and the j-th data line (DLj) as an example.

[0044] Referring to FIG. 2, the pixel (PX) includes a switching transistor (ST), a driving transistor (DT), a sensing transistor (SST), a storage capacitor (Cst), and a light-emitting element (LD).

[0045] The first electrode of the switching transistor (ST) is electrically connected to the j-th data line (DLj), and the second electrode is electrically connected to the first node (N1). The gate electrode of the switching transistor (ST) is electrically connected to the i-th first gate line (GL1i). The switching transistor (ST) is turned on when a gate-on level gate signal is applied to the i-th first gate line (GL1i), and transmits the data signal applied to the j-th data line (DLj) to the first node (N1).

[0046] The first electrode of the storage capacitor (Cst) is electrically connected to the first node (N1), and the second electrode is connected to the first electrode (e.g., the anode electrode) of the light-emitting element (LD). The storage capacitor (Cst) can charge a voltage corresponding to the difference between the voltage applied to the first node (N1) and the voltage applied to the first electrode of the light-emitting element (LD).

[0047] The first electrode of the driving transistor (DT) is configured to receive a high potential driving voltage (ELVDD), and the second electrode is electrically connected to the first electrode of the light-emitting element (LD). The gate electrode of the driving transistor (DT) is electrically connected to the first node (N1). The driving transistor (DT) is turned on when a gate-on level voltage is applied through the first node (N1), and can control the amount of driving current flowing through the light-emitting element (LD) in response to the voltage provided to the gate electrode.

[0048] The first electrode of the sensing transistor (SST) is electrically connected to the j-th sensing line (SLj), and the second electrode is electrically connected to the first electrode of the light-emitting element (LD). The gate electrode of the sensing transistor (SST) is electrically connected to the i-th second gate line (GL2i). The sensing transistor (SST) is turned on when a sensing signal of the gate-on level is applied to the i-th second gate line (GL2i), and transmits the reference voltage applied to the j-th sensing line (SLj) to the first electrode of the light-emitting element (LD).

[0049] The light-emitting element (LD) outputs light corresponding to the driving current. The light-emitting element (LD) can output light corresponding to any one of red, green, blue, and white. The light-emitting element (LD) may be an organic light-emitting diode (OLED) or a micro- to nano-scale inorganic light-emitting diode, but the present embodiment is not limited thereto. Hereinafter, the technical concept of the present embodiment is explained with reference to an embodiment in which the light-emitting element (LD) is composed of an organic light-emitting diode.

[0050] In this embodiment, the structure of the pixels (PXij) is not limited to that shown in FIG. 2. According to the embodiment, the pixels (PXij) may further include at least one element for compensating the threshold voltage of the driving transistor (DT) or for initializing the voltage of the gate electrode of the driving transistor (DT) and / or the voltage of the first electrode of the light-emitting element (LD).

[0051] In FIG. 2, an example is shown in which the switching transistor (ST), the driving transistor (DT), and the sensing transistor (SST) are NMOS transistors, but the present invention is not limited thereto. For example, at least some or all of the transistors constituting each pixel (PX) may be composed of PMOS transistors. In various embodiments, the switching transistor (ST), the driving transistor (DT), and the sensing transistor (SST) may each be implemented as a Low Temperature Poly Silicon (LTPS) thin film transistor, an oxide thin film transistor, or a Low Temperature Polycrystalline Oxide (LTPO) thin film transistor.

[0053] FIG. 3 is a cross-sectional view of a display panel according to one embodiment.

[0054] Referring to FIG. 3, a pixel (PX) according to one embodiment may include a substrate (100), a circuit element layer formed on the substrate (100) and having at least one circuit element, and a light-emitting element layer having a light-emitting element (LD).

[0055] The substrate (100) may be a transparent substrate as a base substrate for the display panel (50). The substrate (100) may be a rigid substrate including glass or reinforced glass or a flexible substrate made of plastic material.

[0056] The circuit element layer is formed on the substrate (100) and may include circuit elements (e.g., transistors and capacitors, etc.) and wiring that constitute a pixel (PX).

[0057] A first conductive layer may be disposed on the substrate (100). The first conductive layer may include an auxiliary wiring (110). The auxiliary wiring (110) may be connected to a second power line (PL2) to which a low potential driving voltage (ELVSS) is applied.

[0058] A buffer layer (120) is disposed on a substrate (100) to cover a first conductive layer. The buffer layer (120) can prevent ions or impurities from diffusing from the substrate (100) and block moisture penetration.

[0059] An insulating layer (130) may be formed on the buffer layer (120). A second conductive layer may be disposed on the insulating layer (130). The second conductive layer may include a connecting electrode (140). The connecting electrode (140) is in contact with an auxiliary wiring (110) through a contact hole penetrating the insulating layer (130) and the buffer layer (120).

[0060] The circuit element layer can be covered by a passivation layer (150) and an overcoat layer (160). The passivation layer (150) is an insulating film for protecting the lower elements, and the overcoat layer (160) may be a flattening film for mitigating the step difference of the lower structure.

[0061] A light-emitting element layer is formed on an overcoat layer (160) and includes light-emitting elements (LDs). The light-emitting element (LD) includes an anode electrode (210), a light-emitting layer (220), and a cathode electrode (240).

[0062] The anode electrode (210) is formed on the overcoat layer (160). The anode electrode (210) may be composed of a transparent conductive material such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), or ZnO (Zinc Oxide). When the anode electrode (210) is a reflective electrode, the anode electrode (210) may be formed as a triple layer composed of a transparent conductive layer / reflective layer (metal oxide layer) / transparent conductive layer. For example, the anode electrode (210) may be composed of a triple layer including ITO / Ag / ITO.

[0063] A bank (250) may be formed on the overcoat layer (160). The bank (250) may be formed to expose a portion of the anode electrode (210), e.g., the central area, while covering the remaining portion, e.g., the edges. The exposed portion of the anode electrode (210) not covered by the bank (250) may be defined as the light-emitting portion (EA) of the pixel (PX).

[0064] In one embodiment, the bank (250) may have a stacked structure of a hydrophilic bank (251) and a hydrophobic bank (252). The hydrophilic bank (251) may expose the central region of the anode electrode (210) and cover the edges. The exposed region of the anode electrode (210) not covered by the hydrophilic bank (251) may be defined as a light-emitting region (EA). The hydrophilic bank (251) is formed of a hydrophilic inorganic insulating material such as silicon oxide (SiO2) or silicon nitride (SiNx) to allow the solution to spread well during the formation of the light-emitting layer (220) described later.

[0065] A hydrophobic bank (252) may be formed in a portion of the hydrophilic bank (251). The hydrophobic bank (252) may be placed between pixel rows to partition the pixel rows. The hydrophobic bank (252) is configured such that at least one region, for example, the upper region, is hydrophobic to prevent color mixing between pixel rows.

[0066] A light-emitting layer (220) is formed on an exposed area of ​​an anode electrode (210) surrounded by a bank (250). In one embodiment, the light-emitting layer (220) can be formed through a solution process. For example, a solution for forming the light-emitting layer (220) can be applied within a light-emitting area (EA). The solution can be prepared by mixing an organic material constituting the light-emitting layer (220) with a solvent. The solution can be jetted onto the light-emitting area through an inkjet device, such as one equipped with a nozzle mounted on an inkjet head. The applied ink dries to form the light-emitting layer (220). The light-emitting layer (220) formed through the solution process may have a surface in the central area lower than the surface in the edge area.

[0067] In one embodiment, a hole injection layer (211, Hole Injection Layer; HIL) and a hole transport layer (212, Hole Transport Layer; HTL), etc., may be further disposed between the light-emitting layer (220) and the anode electrode (210). The hole injection layer (211) and the hole transport layer (212) may be formed through a solution process similar to the light-emitting layer (220).

[0068] An organic layer (230) may be formed on the light-emitting layer (220). The organic layer (230) may be formed broadly on the substrate (100) to cover the light-emitting layer (220) and the bank (250). The organic layer (230) may be formed by an evaporation deposition method such as thermal deposition or a physical vapor deposition method such as sputtering. The organic layer (230) may be, for example, an electron transport layer (ETL). The electron transport layer serves to smoothly transfer electrons injected from the cathode electrode (240) to the light-emitting layer (220).

[0069] A cathode electrode (240) is formed on an organic layer (230). The cathode electrode (240) can be formed broadly on the substrate (100). The cathode electrode (240) can be formed from a transparent conductive material (TCO) or a semi-transmissive conductive material capable of transmitting light. The cathode electrode (240) can be formed via evaporative deposition or physical vapor deposition, similar to the organic layer (230). For example, the cathode electrode (240) can be formed by co-positioning silver (Ag) and magnesium (Mg) and depositing them on the organic layer (230).

[0070] In this embodiment, the display panel (50) may include an auxiliary electrode contact part (CA1) for connecting the cathode electrode (240) to a low potential driving voltage (ELVSS). Below, the detailed configuration of the auxiliary electrode contact part (CA1) will be described with reference to FIG. 4.

[0072] FIG. 4 is a cross-sectional view showing an auxiliary electrode contact part (CA1) according to the first embodiment.

[0073] Referring to FIG. 3 and FIG. 4 together, the light-emitting element layer further includes an auxiliary electrode (260) for connecting the cathode electrode (240) and the connecting electrode (140). The auxiliary electrode (260) is formed on the same layer as the anode electrode (210) and can be placed in the auxiliary electrode contact portion (CA1). The auxiliary electrode (260) is contacted to the connecting electrode (140) through a contact hole penetrating the overcoat layer (160) and the passivation layer (150). Since the connecting electrode (140) is connected to the second power line (PL2) through the auxiliary wiring (110), the auxiliary electrode (260) can be connected to the second power line (PL2).

[0074] The auxiliary electrode (260) can be composed of the same material as the anode electrode (210) and formed through the same process. In one embodiment, the auxiliary electrode (260) can be formed as a triple layer composed of a first transparent conductive layer (261) / reflective layer (262, metal oxide layer) / second transparent conductive layer (263). For example, the auxiliary electrode (260) can be composed of a triple layer including ITO / Ag / ITO.

[0075] An electrode hole (H) may be formed in the auxiliary electrode (260). At least one electrode hole (H) may be patterned in the auxiliary electrode (260). This auxiliary electrode (260) may be formed, for example, by stacking the first transparent conductive layer (261), the reflective layer (262), and the second transparent conductive layer (263) in sequence, and then applying a mask containing a pattern corresponding to the electrode hole (H) to perform a batch etching (e.g., wet etching) of the triple layer. At this time, a portion of the overcoat layer (160) stacked on the lower part of the auxiliary electrode (260) may be exposed to the upper side by the electrode hole (H). Additionally, the reflective layer (262) interposed between the transparent conductive layers (261, 263) may be exposed on the inner side of the electrode hole (H). The auxiliary electrode (260) may be covered by a transparent conductive layer (270). The transparent conductive layer (270) can cover an auxiliary electrode (260) patterned with electrode holes (H) and an area of ​​the overcoat layer (160) exposed by the electrode holes (H). At this time, a step is formed in the transparent conductive layer (270) around the electrode holes (H) of the auxiliary electrode (260). Accordingly, a groove (271) covering the electrode holes (H) can be formed in the transparent conductive layer (270).

[0076] The transparent conductive layer (270) covers the auxiliary electrode (260) as a whole and can be formed with an area larger than that of the auxiliary electrode (260). Through this transparent conductive layer (270), the overall electrode tip length of the auxiliary electrode contact portion (CA1) can be increased. Accordingly, an electrical connection between the auxiliary electrode (260) and the cathode electrode (240) at the auxiliary electrode contact portion (CA1) can be made stably and easily. In one embodiment, the thickness of the transparent conductive layer (270) is approximately 140 It may be Å*, but is not limited thereto.

[0077] The transparent conductive layer (270) may be composed of a transparent conductive material such as ITO, IZO, or ZnO. For example, the transparent conductive layer (270) may be composed of the same material as the transparent conductive layer constituting the auxiliary electrode (260). However, the present invention is not limited thereto.

[0078] The bank (250) may be formed to expose a portion of the transparent conductive layer (270). For example, the bank (250) may be formed to expose the groove portion (271) of the transparent conductive layer (270) while covering the remaining portion. The exposed portion of the transparent conductive layer (270) not covered by the bank (250) may be defined as the auxiliary electrode contact portion (CA1) of the pixel (PX).

[0079] In one embodiment, an etching process may be performed on the bank (250) to form an opening corresponding to the auxiliary electrode contact portion (CA1). The etching process may be performed, for example, by applying a selective etching solution while a mask is applied to the bank (250). After the etching process, the mask and etching solution residues may be removed through an ashing process to completely expose the transparent conductive layer (270) to the outside from the auxiliary electrode contact portion (CA1).

[0080] During the ashing process, the transparent conductive layer (270) can protect the inner surface of the electrode hole (H). The reflective layer (262) exposed on the inner surface of the electrode hole (H) can form particles by the ashing process, thereby forming a dark spot on the display panel (50). In this embodiment, since the inner surface of the electrode hole (H) is covered by the transparent conductive layer (270), the formation of particles during the ashing process can be prevented.

[0081] The organic layer (230) and the cathode electrode (240) are formed broadly on the substrate (100) and thus cover a portion of the exposed transparent conductive layer (270). At this time, the organic layer (230), which has relatively poor step coverage characteristics, may be cut off around the groove (271) of the transparent conductive layer (270). In one embodiment, the organic layer (230) may be cut off from the inner surface of the groove (271), but is not limited thereto. As the organic layer (230) is cut off, a portion of the inner surface of the groove (271) of the transparent conductive layer (270) may be exposed without being covered by the organic layer (230).

[0082] On the other hand, the cathode electrode (240), which has relatively good step coverage characteristics, is formed continuously without being interrupted around the groove (271) of the transparent conductive layer (270). In one embodiment, the cathode electrode (240) may be interrupted around the groove (271) as illustrated. For example, the cathode electrode (240) may be interrupted on the inner side of the groove (271). Since the step coverage characteristics of the cathode electrode (240) are better than the step coverage characteristics of the organic layer (230), the cathode electrode (240) may be in direct contact with the inner side of the groove (271) that is not covered by the organic layer (230).

[0083] The residue of the disconnected organic layer (230) and cathode electrode (240) can be laminated within the groove (271). That is, the organic layer (230) and cathode electrode (240) are disconnected around the groove (271), and the residue (230') of the organic layer (230) and the residue (240') of the cathode electrode (240) can be sequentially laminated on the transparent conductive layer (270) within the groove (271).

[0084] As described above, the cathode electrode (240) is directly contacted by the transparent conductive layer (270) at the auxiliary electrode contact portion (CA1). The cathode electrode (240) is contacted by the connecting electrode (140) through the transparent conductive layer (270) and the auxiliary electrode (260). Since the connecting electrode (140) is connected to the second power line (PL2) through the auxiliary wiring (110), the cathode electrode (240) can be connected to the second power line (PL2).

[0085] Referring again to FIG. 3, an encapsulation layer (300) may be formed on the cathode electrode (240). The encapsulation layer (300) serves to prevent external moisture from penetrating into the light-emitting layer (220). The encapsulation layer (300) may be made of an inorganic insulating material or may be made of a structure in which an inorganic insulating material and an organic insulating material are alternately stacked, but is not necessarily limited thereto.

[0086] A cover substrate (400) may be formed on the upper portion of the encapsulation layer (300). The cover substrate (400) may be composed of the same material as the substrate (100). This cover substrate (400) may be adhered to the encapsulation layer (300) through an adhesive or the like.

[0087] In various embodiments, a color filter (410) may be further formed between the encapsulation layer (300) and the cover substrate (400). The color filter (410) may be placed in the light-emitting region (EA). The color filter (410) is a wavelength-selective optical filter that selectively transmits only a portion of the wavelength band of incident light by transmitting light of a specific wavelength band and blocking light of another specific wavelength band, and may be composed of a photosensitive resin containing a colorant such as a pigment or dye. The light generated from the light-emitting element (LD) and passed through the color filter (410) may have a color of red, green, or blue. If a pixel (PX) displays a white color, the color filter (410) may be omitted for that pixel (PX).

[0089] FIG. 5 is a cross-sectional view showing an auxiliary electrode contact part (CA2) according to a second embodiment.

[0090] Compared to the embodiment of FIG. 4, in the auxiliary electrode contact portion (CA2) according to the second embodiment, the selective etching solution used during the electrode hole (H) etching process may have greater reactivity to the reflective layer (265) than to the transparent conductive layer. Accordingly, the reflective layer (265) may be over-etched, and an undercut (UC) may occur between the upper and lower transparent conductive layers (261, 263) and the reflective layer (265). That is, the reflective layer (265) is more recessed on the inner side than the upper and lower transparent conductive layers (261, 263).

[0091] In this embodiment, the side of the exposed reflective layer (265) may have an inverted tapered shape. The groove (273) of the transparent conductive layer (272) covering the auxiliary electrode (264) may have an inverted tapered shape on its side, following the shape of the auxiliary electrode (264).

[0092] Then, the organic layer (230), which has poor step coverage characteristics, can be more easily severed around the groove (273) of the transparent conductive layer (272). When the inner surface of the groove (273) of the transparent conductive layer (272) is exposed over a wider area due to the severance of the organic layer (230), the cathode electrode (240) formed after the organic layer (230) can be more effectively contacted with the transparent conductive layer (272) on the inner surface of the groove (271).

[0093] When the cathode electrode (240) is in direct contact with the transparent conductive layer (272) over a wider area, the electrical resistance between the cathode electrode (240) and the transparent conductive layer (272) is reduced, allowing for efficient power transfer.

[0095] FIG. 6 is a cross-sectional view showing an auxiliary electrode contact part (CA3) according to a third embodiment.

[0096] Compared to the embodiment of FIG. 5, in the auxiliary electrode contact portion (CA3) according to the third embodiment, the selective etching solution used during the electrode hole (H) etching process may have greater reactivity to the reflective layer (267) than to the transparent conductive layer. Accordingly, the reflective layer (267) may be over-etched, and an undercut (UC) may occur between the upper and lower transparent conductive layers (261, 263) and the reflective layer (267). That is, on the inner side of the electrode hole (H), the reflective layer (267) is recessed further outward than the upper and lower transparent conductive layers (261, 263).

[0097] In this embodiment, the side of the exposed reflective layer (267) may have a tapered shape. The groove (275) of the transparent conductive layer (274) covering the auxiliary electrode (266) may have a tapered shape on its side, following the shape of the auxiliary electrode (266).

[0098] Then, the cathode electrode (240), which has good step coverage characteristics, can be formed more easily and continuously without being interrupted in the groove (275) of the transparent conductive layer (274). In this embodiment, the cathode electrode (240) is formed to completely cover the residue (230') of the organic layer (230) formed within the groove (275).

[0099] If the cathode electrode (240) is maintained continuity without being largely disconnected on the transparent conductive layer (274), the area of ​​direct contact between the cathode electrode (240) and the transparent conductive layer (274) increases, thereby reducing the electrical resistance between the cathode electrode (240) and the transparent conductive layer (274) and improving the contact accuracy. Then, power transfer to the cathode electrode (240) is efficiently carried out, and the power consumption of the display panel (50) can be reduced.

[0101] FIG. 7 is a cross-sectional view showing an auxiliary electrode contact part (CA4) according to the fourth embodiment.

[0102] Compared to the first embodiment, in the auxiliary electrode contact portion (CA4) according to the fourth embodiment, the auxiliary electrode (268) may be formed as a double layer in which a transparent conductive layer (261) and a reflective layer (262) are laminated. For example, the auxiliary electrode (268) may be composed of a double layer including ITO / Ag.

[0103] In this embodiment, the reflective layer (262) is completely exposed on top of the auxiliary electrode (268). The transparent conductive layer (270) covers the entire exposed area of ​​the reflective layer (262). This prevents particles from being generated from the reflective layer (262).

[0105] FIG. 8 is a cross-sectional view showing an auxiliary electrode contact part (CA5) according to the fifth embodiment.

[0106] Compared to the first embodiment, in the auxiliary electrode contact portion (CA5) according to the fifth embodiment, the auxiliary electrode (269) may be formed as a single layer composed of a transparent conductive layer (261). For example, the auxiliary electrode (269) may be composed of ITO.

[0107] The transparent conductive layer (270) covers the auxiliary electrode (269). The transparent conductive layer (270) covers the auxiliary electrode (269) as a whole and can be formed with an area larger than that of the auxiliary electrode (269). Through this transparent conductive layer (270), the overall electrode tip length of the auxiliary electrode contact portion (CA5) can be increased. Accordingly, an electrical connection between the auxiliary electrode (269) and the cathode electrode (240) at the auxiliary electrode contact portion (CA5) can be made stable and easily.

[0109] FIG. 9 is a cross-sectional view showing an auxiliary electrode contact part (CA6) according to the 6th embodiment.

[0110] Compared to the first embodiment, the auxiliary electrode contact portion (CA6) according to the sixth embodiment omits the auxiliary electrode (260) and includes only the transparent conductive layer (270). Since the auxiliary electrode contact portion (CA6) includes only the transparent conductive layer (270), no particles are generated during the ashing process of the bank (250). Additionally, the transparent conductive layer (270) is formed relatively widely on the auxiliary electrode contact portion (CA6), so the electrode tip length of the auxiliary electrode contact portion (CA6) can be increased.

[0112] FIGS. 10 to 16 are drawings illustrating a method for manufacturing a display device according to one embodiment. In FIGS. 10 to 16, the lower layers of the overcoat layer (160) are omitted for convenience of explanation. However, circuit elements, auxiliary wiring (110), and connecting electrodes (140), etc., may be formed on the lower part of the overcoat layer (160) as described with reference to FIG. 3.

[0113] Referring to FIGS. 10 and 11, an auxiliary electrode (260) is formed on the overcoat layer (160) at the auxiliary electrode contact portion (CA). Although not illustrated, the auxiliary electrode (260) is connected to the connecting electrode (140).

[0114] The auxiliary electrode (260) may be formed as a triple layer composed of a transparent conductive layer (261), a reflective layer (262), and a transparent conductive layer (263). The transparent conductive layer (261, 263) may be composed of, for example, ITO, and the reflective layer (262) may be composed of, for example, a metallic material such as silver or a silver alloy. At least one electrode hole (H) is formed in the auxiliary electrode (260). The transparent conductive layer (261), the reflective layer (262), and the transparent conductive layer (263) constituting the auxiliary electrode (260) may be exposed on the inner side of the electrode hole (H).

[0115] The auxiliary electrode (260) can be formed by stacking a transparent conductive layer (261) / reflective layer (262) / transparent conductive layer (263) in order as shown in FIG. 10, and then applying a mask having a pattern corresponding to the electrode hole (H) as shown in FIG. 11, and then performing a batch etching (e.g., wet etching).

[0116] Referring to FIG. 12, a transparent conductive layer (270) may subsequently be formed on an auxiliary electrode (260). The transparent conductive layer (270) may be formed to cover an area of ​​the auxiliary electrode (260) patterned with electrode holes (H) and an overcoat layer (160) exposed by the electrode holes (H). At this time, a step is formed in the transparent conductive layer (270) around the electrode holes (H) of the auxiliary electrode (260). Accordingly, a groove (271) covering the electrode holes (H) may be formed in the transparent conductive layer (270).

[0117] The transparent conductive layer (270) covers the auxiliary electrode (260) as a whole and can be formed with an area larger than that of the auxiliary electrode (260). Through this transparent conductive layer (270), the overall electrode tip length of the auxiliary electrode contact portion (CA) can be increased. Accordingly, an electrical connection between the auxiliary electrode (260) and the cathode electrode (240) at the auxiliary electrode contact portion (CA) can be made stably and easily. In one embodiment, the thickness of the transparent conductive layer (270) is approximately 140 It may be Å*, but is not limited thereto.

[0118] The transparent conductive layer (270) may be composed of a transparent conductive material such as ITO, IZO, or ZnO. For example, the transparent conductive layer (270) may be composed of the same material as the transparent conductive layer constituting the auxiliary electrode (260). However, the present invention is not limited thereto.

[0119] Referring to FIG. 13, a bank (250) may subsequently be formed on the transparent conductive layer (270). The bank (250) may be formed to expose a portion of the transparent conductive layer (270), for example, around the groove (271), while covering the remaining portion.

[0120] In one embodiment, the bank (250) may have a stacked structure of a hydrophilic bank (251) and a hydrophobic bank (252). The hydrophilic bank (251) is formed of a hydrophilic inorganic insulating material such as silicon oxide (SiO2) or silicon nitride (SiNx) to allow the solution to spread well when forming the light-emitting layer (220) described later.

[0121] A hydrophobic bank (252) may be formed in a portion of the hydrophilic bank (251). At least a portion of the surface of the hydrophobic bank (252) may be formed to be hydrophobic. For example, the hydrophobic bank (252) may be formed by applying a solution of a hydrophobic material, such as fluorine (F), to an organic insulator and then performing a photolithography process. During the photolithography process, the hydrophobic material, such as fluorine, may move to the top of the hydrophobic bank (252) by the light irradiated thereon, and accordingly, the top surface of the hydrophobic bank (252) may have hydrophobic properties and the remaining portion may have hydrophilic properties.

[0122] In this embodiment, after a hydrophilic bank (251) is formed on a transparent conductive layer (270), a hydrophobic bank (252) may be formed on the hydrophilic bank (251). Specifically, the hydrophilic bank (251) may be formed by etching the inorganic insulating layer while applying a mask corresponding to the shape of the hydrophilic bank (251) after a hydrophilic inorganic insulating layer is laminated on the transparent conductive layer (270). After the etching process, the electrode hole (H) of the auxiliary electrode (260) laminated on the bottom and the surrounding area thereof may be exposed to the top.

[0123] After the etching process of the hydrophilic bank (251), an ashing process may be performed to remove the mask and residue. During the ashing process, the transparent conductive layer (270) can protect the inner surface of the electrode hole (H). Since the inner surface of the electrode hole (H) is covered by the transparent conductive layer (270), it is possible to prevent the formation of particles during the ashing process.

[0124] Subsequently, a solution mixed with a hydrophobic material such as fluorine (F) is applied to an organic insulator on a hydrophilic bank (251), and then a hydrophobic bank (252) can be formed through a photolithography process.

[0125] Referring to FIG. 14, an organic layer (230) is formed. The organic layer (230) is formed over a wide area through an evaporative deposition method such as thermal deposition or a physical vapor deposition method such as sputtering, so as to cover the bank (250) and the transparent conductive layer (270). In one embodiment, the organic layer (230) may be interrupted around the groove (271) of the transparent conductive layer (270) according to the step coverage characteristics. As the organic layer (230) is interrupted, a portion of the inner surface of the groove (271) of the transparent conductive layer (270) may be exposed without being covered by the organic layer (230). The residue (230') of the interrupted organic layer (230) may be stacked within the groove (271).

[0126] Referring to FIG. 15, a cathode electrode (240) is formed on an organic layer (230). The cathode electrode (240) can be formed over a wide area through a evaporative deposition method such as thermal deposition or a physical vapor deposition method such as sputtering to cover the organic layer (230). The cathode electrode (240) can be disconnected from the inner surface of the groove (271) according to the step coverage characteristics. Since the step coverage characteristics of the cathode electrode (240) are better than the step coverage characteristics of the organic layer (230), the cathode electrode (240) can be directly contacted with the inner surface of the groove (271) that is not covered by the organic layer (230). The residue (240') of the disconnected cathode electrode (240) can be stacked within the groove (271).

[0127] Referring to FIG. 16, an encapsulation layer (300) may be formed on the cathode electrode (240). According to an embodiment, various functional layers, such as a protective layer, a polarizing layer, and a touchscreen layer, may be further laminated on the encapsulation layer (300).

[0129] A person skilled in the art to which the present invention pertains will understand that the present invention may be implemented in other specific forms without altering its technical concept or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts should be interpreted as being included within the scope of the present invention. Explanation of the symbols

[0130] 1: Display device 10: Timing control unit 20: Gate drive unit 30: Data driver 40: Power supply 50: Display panel

Claims

Claim 1 A display device comprising: a substrate including a light-emitting region and an auxiliary electrode contact portion; an auxiliary electrode disposed in the auxiliary electrode contact portion and having an electrode hole formed therein; an overcoat layer disposed below the auxiliary electrode; a transparent conductive layer covering the auxiliary electrode and having a groove formed above the electrode hole; a first bank exposing the area around the groove of the transparent conductive layer and covering the remaining area; a second bank formed on the first bank; an organic layer formed on the second bank and the exposed transparent conductive layer; and a cathode electrode formed on the organic layer, wherein the transparent conductive layer covers a portion of the overcoat layer exposed by the auxiliary electrode and the electrode hole, and the cathode electrode is in direct contact with the inner surface of the groove of the transparent conductive layer. Claim 2 A display device according to claim 1, wherein the organic layer is disconnected from the periphery of the groove portion to expose the inner surface of the groove portion, and the cathode electrode is in direct contact with the exposed inner surface of the groove portion. Claim 3 A display device according to claim 1, wherein the transparent conductive layer covers the auxiliary electrode as a whole and is formed with an area larger than that of the auxiliary electrode. Claim 4 A display device according to claim 1, wherein the auxiliary electrode has a structure in which a first transparent conductive layer, a reflective layer, and a second transparent conductive layer are laminated, and the reflective layer is exposed on the inner surface of the electrode hole and covered by the transparent conductive layer. Claim 5 A display device according to claim 4, wherein the reflective layer is recessed further from the inner surface of the electrode hole than the first and second transparent conductive layers. Claim 6 A display device in which, in paragraph 5, the reflective layer has a side surface in the shape of an inverse taper, and the groove portion of the transparent conductive layer has an inverse taper shape following the shape of the reflective layer. Claim 7 A display device according to claim 5, wherein the reflective layer is tapered on its side and the groove portion of the transparent conductive layer is tapered along the shape of the reflective layer. Claim 8 A display device according to claim 1, wherein the auxiliary electrode has a structure in which a first transparent conductive layer and a reflective layer are laminated, and the exposed reflective layer is entirely covered by the transparent conductive layer. Claim 9 A display device according to claim 1, wherein the auxiliary electrode has a structure in which a first transparent conductive layer, a reflective layer, and a second transparent conductive layer are laminated, and the second transparent conductive layer is entirely covered by the transparent conductive layer. Claim 10 A display device according to claim 1, wherein the auxiliary electrode has a structure in which a first transparent conductive layer is laminated, and the first transparent conductive layer is entirely covered by the transparent conductive layer. Claim 11 A display device according to claim 1, wherein the first bank is a hydrophilic bank and the second bank is a hydrophobic bank. Claim 12 A method for manufacturing a display device comprising: forming an auxiliary electrode on an overcoat layer at an auxiliary electrode contact portion of a substrate including a light-emitting region and an auxiliary electrode contact portion; forming an electrode hole in the auxiliary electrode; forming a transparent conductive layer covering the auxiliary electrode; forming a bank covering at least one region of the transparent conductive layer and the remaining region; forming an organic layer on the bank and the exposed transparent conductive layer; and forming a cathode electrode on the organic layer, wherein the transparent conductive layer covers one region of the overcoat layer exposed by the auxiliary electrode and the electrode hole. Claim 13 A method for manufacturing a display device according to claim 12, wherein the transparent conductive layer covers the auxiliary electrode as a whole and is formed with an area larger than that of the auxiliary electrode. Claim 14 A method for manufacturing a display device according to claim 12, wherein the step of forming the auxiliary electrode comprises stacking a first transparent conductive layer, a reflective layer, and a second transparent conductive layer, and the step of forming an electrode hole in the auxiliary electrode comprises performing an etching process while applying a mask to form the electrode hole, and the reflective layer is exposed on the inner side of the electrode hole and covered by the transparent conductive layer. Claim 15 A method for manufacturing a display device according to claim 14, wherein the reflective layer is over-etched compared to the first and second transparent conductive layers during the etching process. Claim 16 A method for manufacturing a display device according to claim 14, wherein the step of forming the bank comprises: a step of forming an insulating layer; a step of forming the bank by performing an etching process with a mask applied; and a step of removing the mask by performing an ashing process. Claim 17 A method for manufacturing a display device according to claim 16, wherein the organic layer and the cathode electrode are widely formed on the substrate through evaporation deposition or physical vapor deposition. Claim 18 A display device according to claim 1, wherein the organic layer is disconnected from the periphery of the groove portion to expose the inner surface of the groove portion, and the cathode electrode is in direct contact only with the exposed inner surface of the groove portion of the transparent conductive layer. Claim 19 A method for manufacturing a display device according to claim 12, wherein the transparent conductive layer includes a groove covering the electrode hole of the auxiliary electrode, the organic layer is cut around the groove of the transparent conductive layer to expose the inner surface of the groove, and the cathode electrode is in direct contact only with the exposed inner surface of the groove of the transparent conductive layer.

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