Electroluminescence display device

Abstract

The present specification relates to an electroluminescent display device, and an electroluminescent display device according to one embodiment of the present specification comprises a substrate including a subpixel area and a cathode contact area located on at least one side of the subpixel area, an interlayer insulating layer disposed on the substrate, an auxiliary electrode disposed on the interlayer insulating layer and having an upper surface that is exposed in at least a portion of the cathode contact area, a protective layer disposed to cover at least a portion of the auxiliary electrode, a cathode contact electrode disposed on the protective layer, an organic light-emitting layer disposed on the cathode contact electrode, and a cathode electrode disposed on the organic light-emitting layer, wherein the protective layer overlaps at least a portion of the cathode contact area and comprises a plurality of trench structures from which the protective layer is removed.

Description

Technology Field

[0001] This specification relates to an electroluminescent display device, and specifically provides a display device in which a moisture-proof structure is applied to the cathode contact area. Background Technology

[0002] As the information society develops, the demand for display devices for displaying images is increasing in various forms. Accordingly, various display devices such as Liquid Crystal Displays (LCDs), Plasma Display Panels (PDPs), Quantum Dot Light Emitting Displays (QLEDs), and Organic Light Emitting Displays (OLEDs) are being utilized recently.

[0003] Meanwhile, recently, active research is being conducted on electroluminescence displays, such as organic light-emitting displays.

[0004] Conventionally, when manufacturing an electroluminescent display device, a cathode contact area was formed on one side of the pixel area to lower the resistance of the cathode electrode of the light-emitting element. Since the cathode contact area acts as a moisture permeation path, there is a problem in that pixels adjacent to the cathode contact area fail to operate due to moisture permeation, resulting in a fade-out. The problem to be solved

[0005] Conventional electroluminescent display devices had a problem in which brightness non-uniformity occurred due to the high resistance of the cathode electrode of the light-emitting element. In addition, in structures designed to lower the cathode electrode, there was a reliability issue in which subpixels were vulnerable to fade-out due to moisture penetration. Accordingly, the inventors of this specification provide a display device in which pixels have high reliability against moisture penetration while providing uniform resistance of the cathode electrode across the entire active area of ​​the electroluminescent display device.

[0006] The problem to be solved according to one embodiment of the present specification is to provide an electroluminescent display device in which the cathode electrode and the auxiliary power line can be stably contacted, and the pixel has high reliability regarding moisture permeability.

[0007] The problems to be solved according to one embodiment of this specification are not limited to those mentioned above, and other unmentioned problems will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0008] An electroluminescent display device according to one embodiment of the present specification comprises a substrate including a subpixel area and a cathode contact area located on at least one side of the subpixel area, an interlayer insulating layer disposed on the substrate, an auxiliary electrode disposed on the interlayer insulating layer and having an upper surface that is exposed in at least a portion of the cathode contact area, a protective layer disposed to cover at least a portion of the auxiliary electrode, a cathode contact electrode disposed on the protective layer, an organic light-emitting layer disposed on the cathode contact electrode, and a cathode electrode disposed on the organic light-emitting layer, wherein the protective layer overlaps in at least a portion with the cathode contact area and comprises a plurality of trench structures from which the protective layer is removed.

[0009] Specific details according to various examples of this specification, other than the means for solving the problem mentioned above, are included in the description and drawings below. Effects of the invention

[0010] According to one example of the present specification, there is an effect of providing uniform resistance of the cathode electrode across the entire active region of the electroluminescent display device.

[0011] In addition, according to one example of the present specification, the resistance to moisture penetration of the pixel is improved by blocking or extending the path for moisture penetration in the cathode contact area of ​​the electroluminescent display device.

[0012] The effects of this specification are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description below. Brief explanation of the drawing

[0013] FIG. 1 is a plan view of an electroluminescent display device according to the present specification. FIG. 2 illustrates the planar structure of area A of FIG. 1 according to an example of the present specification. FIG. 3 illustrates the planar structure of area A of FIG. 1 according to another example of the present specification. Figure 4 is a cross-sectional view taken along the line I-I' of Figure 2. Figure 5 is an enlarged view of section B of Figure 4. Specific details for implementing the invention

[0014] 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 the invention, and this specification is defined only by the scope of the claims.

[0015] 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 depicted items. 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.

[0016] In interpreting the components, they are interpreted to include a margin of error even in the absence of a separate explicit statement.

[0017] In the case of describing a positional relationship, for example, when the positional relationship between two parts is described using expressions such as 'on,' 'upper,' 'lower,' or 'next to,' one or more other parts may be located between the two parts unless 'immediately' or 'directly' is used.

[0018] Although terms such as "first," "second," etc. are used to describe various components, 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.

[0019] 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 may be implemented together in an associated relationship.

[0020] FIG. 1 is a plan view according to one example of the present specification.

[0021] Referring to FIG. 1, an electroluminescent display device according to one example of the present specification may include a light-emitting display panel (1) and a panel driving circuit (3).

[0022] The display panel (1) may include a substrate (10), an active area (AA), an inactive area, a first power line (60), a second power line (70), and a gate driving circuit (50).

[0023] The substrate (10) may be a glass substrate, a thin glass substrate that can be bent or curved, a plastic substrate, or a silicon wafer substrate.

[0024] The active area (AA) of the substrate (10) is an area where an image is displayed, and may also be expressed as a first area, a display area, a display area, or an active area. For example, the active area (AA) may be placed in the remaining part of the substrate (10) excluding the edge portion.

[0025] The inactive area (IA) is an area where no image is displayed, and may also be expressed as a second area, non-display area, non-display area, or inactive area. For example, the non-display area may be placed at the edge portion of the substrate (10) to surround the active area (AA).

[0026] A predetermined region indicated by A in FIG. 1 may be a region including at least one transparent region and a non-transparent region. Here, the non-transparent region may include a light-emitting region including at least one pixel. The region indicated by A in FIG. 1 will be described later with reference to FIG. 2 and 3.

[0027] An electroluminescent display device according to one example of the present specification may include a first power line (60) and a second power line (70) disposed in an inactive area (IA). Here, a base voltage (VSS) and a power voltage (VDD) may be applied to the first power line (60) and the second power line (70), respectively. The first power line (60) and the second power line (70) are controlled by a panel driving circuit (3) to supply the base voltage (VSS) and the power voltage (VDD), respectively, to the pixels of the active area (AA).

[0028] As illustrated in FIG. 1, a pair of first power lines (60) may be arranged in a bar shape in the inactive areas (IA) at the top and bottom of the display panel (1), and may include a plurality of first power link lines (62) connecting the pair of first power lines (60). Additionally, a pair of second power lines (70) may be arranged in a bar shape in the inactive areas (IA) at the top and bottom of the display panel (1), and may include a plurality of second power link lines (72) connecting the pair of second power lines (70).

[0029] In FIG. 1, the first power link wiring (62) may be arranged to overlap with area A of FIG. 1. Specifically, the first power link wiring (62) may be arranged adjacent to the cathode contact area described later. The cathode contact area can improve reliability by providing a structure in which the cathode electrode described later in this specification and the first power link wiring (62) can be stably contacted, and the resistance applied to the cathode electrode can be lowered. Additionally, a display device with improved brightness uniformity can be provided.

[0030] Here, the cathode contact area (CCA) may be defined as an area where at least a portion of the protective layer (150) and flattening layer (160) formed on the upper part of the auxiliary electrode (AE) for electrical contact between the cathode electrode (250) and the first power link wiring (62) are patterned. Additionally, the cathode contact area (CCA) may be defined as an area where at least a portion of the upper surface of the auxiliary electrode (AE) is exposed. The detailed structure of the cathode contact area (CCA) will be described later with reference to FIGS. 2 to 5.

[0031] The gate driving circuit (50) supplies gate signals to gate lines according to a gate control signal provided from the driving circuit section (3) to a plurality of gate pads of the pad section (PP) and through a link line. For example, the gate driving circuit (50) may be placed in at least one of the two non-active regions (IA) of the substrates (10) facing each other. The gate driving circuit (50) may be formed in a non-display area outside one or both sides of the display area of ​​the display panel (1) using a GIP (gate driver in panel) method. Alternatively, the gate driving unit may be manufactured as a driving chip, mounted on a flexible film, and attached to a non-display area outside one or both sides of the active area of ​​the electroluminescent display panel (1) using a TAB (tape automated bonding) method.

[0032] A driving circuit section (3) according to one example may include a plurality of flexible circuit films (31), a plurality of data driving integrated circuits (33), a printed circuit board (35), a timing controller (37), and a power circuit section (39).

[0033] Each of the plurality of flexible circuit films (31) can be attached to a pad portion (PP) provided on a substrate (10) and a printed circuit board (35), respectively. For example, one side (or output bonding portion) of each of the plurality of flexible circuit films (31) can be attached to a pad portion (PP) provided on the substrate (10) by a film attachment process using an anisotropic conductive film. The other side (or input bonding portion) of each of the plurality of flexible circuit films (31) can be attached to a printed circuit board (35) by a film attachment process using an anisotropic conductive film.

[0034] Each of the plurality of data driving integrated circuits (33) is individually mounted on each of the plurality of flexible circuit films (31). Each of these plurality of data driving integrated circuits (33) receives pixel data and a data control signal provided by a timing controller (37), and can convert the pixel data into an analog pixel-specific data voltage according to the data control signal and supply it to the corresponding data line.

[0035] The printed circuit board (35) can be connected to the other side of each of the plurality of flexible circuit films (31). The printed circuit board (35) can serve to transmit signals and voltages between the components of the driving circuit section (3).

[0036] The timing controller (37) is mounted on the printed circuit board (35) and can receive image data and timing synchronization signals provided from the display driving system through a user connector placed on the printed circuit board (35).

[0037] The timing controller (37) can generate pixel data by aligning image data to fit a pixel array structure placed in an active area (AA) based on a timing synchronization signal, and can provide the generated pixel data to each of a plurality of data driving integrated circuits (33).

[0038] The timing controller (37) can generate a data control signal and a gate control signal, respectively, based on a timing synchronization signal. The timing controller (37) controls the driving timing of each of the multiple data driving integrated circuits (33) through the data control signal, and through the gate control signal The driving timing of the gate driving circuit (50) can be controlled. For example, the timing synchronization signal may include a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, and a main clock (or dot clock).

[0039] The power circuit section (39) is mounted on a printed circuit board (35) and can generate various power voltages necessary to display an image on a pixel using an input power supplied from the outside and provide them to the corresponding circuit.

[0040] FIG. 2 illustrates the planar structure of area A of FIG. 1 according to one example of the present specification, and FIG. 3 illustrates the planar structure of area A of FIG. 1 according to another example of the present specification.

[0041] Referring to FIG. 2, region A of the active region (AA) shown in FIG. 1 may include a transparent region (TA) and a non-transparent region (NTA), and the non-transparent region (NTA) may include a plurality of sub-pixel regions (SPA) and a cathode contact region (CCA), and may include a first power link wiring (62) that overlaps with at least a portion of a plurality of sub-pixels (SP1, SP2, SP3, SP4).

[0042] An electroluminescent display device according to one example of the present specification may be seen as having an active region (AA) configured in a structure in which the structure of A of FIG. 2 or FIG. 3 described later is repeated. Accordingly, a cathode contact region (CCA) may be seen as being formed in at least a portion between a transmission region (TA) and a subpixel region (SPA). Furthermore, the cathode contact region (CCA) is not placed for every plurality of subpixels (SP1, SP2, SP3, SP4) provided that it satisfies the resistance requirement of a predetermined cathode electrode (250) required by the electroluminescent display device. For example, it may be configured so that one cathode contact region (CCA) is allocated to 4 subpixels, 8 subpixels, 12 subpixels, or 16 subpixels.

[0043] The transmitting area (TA) is an area that allows light incident from the outside to pass through almost as is, and the non-transmitting area (NTA) is an area that does not transmit light incident from the outside. For example, the transmitting area (TA) may be an area with a light transmittance greater than α%, e.g. 90%. And, the non-transmitting area (NTA) may be an area with a light transmittance less than β%, e.g. 50%. In this case, α is a value greater than β. The display panel (1) can see objects or backgrounds located on the back of the display panel (1) due to the transmitting areas (TA).

[0044] The non-transmitting region (NTA) may include a plurality of sub-pixel (SP1, SP2, SP3, SP4) region and a cathode contact region (CCA), and may be provided with first power link wiring (62), second power link wiring (72), reference lines, data lines, and gate lines for driving the plurality of sub-pixels (SP1, SP2, SP3, SP4).

[0045] Here, the first subpixel (SP1) may include a light-emitting element that emits blue light, the second subpixel (SP2) may include a light-emitting element that emits red light, the third subpixel (SP3) may include a light-emitting element that emits green light, and the fourth subpixel (SP4) may include a light-emitting element that emits white light, but is not necessarily limited thereto. For example, the subpixels may be configured without a light-emitting element that emits white light, and may be configured with combinations of colors other than the combination of blue light, red light, and green light.

[0046] According to one example of the present specification, light-emitting elements placed in each of the first to fourth subpixels (SP1, SP2, SP3, SP4) may emit different colored light individually or emit white light in common.

[0047] When each of the first to fourth subpixels (SP1, SP2, SP3, SP4) commonly emits white light, three of the first to fourth subpixels (SP1, SP2, SP3, SP4) may include a color filter (or wavelength conversion member) that converts the white light into different colored light. For example, they may include a blue color filter, a green color filter, and a red color filter.

[0048] For convenience of explanation, the first subpixel (SP1) is a blue subpixel emitting blue light, the second subpixel (SP2) is a red subpixel emitting red light, the third subpixel (SP3) is a green subpixel emitting green light, and the fourth subpixel (SP4) is a white subpixel emitting white light.

[0049] Each of the first subpixel (SP1), second subpixel (SP2), third subpixel (SP3), and fourth subpixel (SP4) may be equipped with a circuit element including a capacitor, a thin-film transistor, etc., and a light-emitting element. The thin-film transistor may include a switching thin-film transistor, a sensing thin-film transistor, and a driving thin-film transistor (T).

[0050] The switching thin-film transistor is switched according to the gate signal supplied to the gate line and serves to supply the data voltage supplied from the data line to the driving thin-film transistor (T).

[0051] The sensing thin-film transistor plays the role of sensing the threshold voltage deviation of the driving thin-film transistor (T), which is the cause of image degradation.

[0052] The driving thin-film transistor (T) is switched according to the data voltage supplied from the switching thin-film transistor and generates a data current from the power supplied from the pixel power line (VDDL) and supplies it to the pixel electrode (210) of the light-emitting element (200). The detailed structure of the driving thin-film transistor (T) and the light-emitting element (200) will be described later with reference to FIG. 4.

[0053] The first power link wiring (62) may be formed along one direction to overlap with at least a portion of a plurality of subpixels (SP1, SP2, SP3, SP4). In FIG. 2, the first power link wiring (62) is shown to overlap with at least a portion of the second subpixel (SP2) and the fourth subpixel (SP4), but the first power link wiring (62) is not limited thereto and may be provided with various electrical connection structures.

[0054] Additionally, an electroluminescent display device according to one example of the present specification may include an auxiliary electrode (AE) extending from one side of the first power link wiring (62) to a cathode contact area (CCA).

[0055] The cathode contact region (CCA) is a region provided in the non-transmitting region (NTA), adjacent to the transmitting region (TA), and may be provided adjacent to at least one plurality of sub-pixel regions (SP1, SP2, SP3, SP4). The cathode contact region (CCA) may be defined as a region where the auxiliary electrode (AE) and the cathode electrode (250) of the light-emitting element (200) described later come into contact, while the transmitting region (TA) is located between the transmitting region (TA) and at least one plurality of sub-pixel regions (SP1, SP2, SP3, SP4).

[0056] FIG. 3 has the same structure as FIG. 2, except that each of the first to fourth subpixels (SP1-SP4) is formed as a pair of split structures. Therefore, redundant descriptions are omitted. Referring to FIG. 3, each of the plurality of subpixels may be configured as a split structure electrically connected by a repair pattern (RP) and a thin-film transistor (T). The first subpixel (SP1) may include a first subpixel first part (SP1-1) and a first subpixel second part (SP1-2) connected by the repair pattern (RP), and the second to fourth subpixels (SP1, SP2, SP3, SP4) may each include a second to fourth subpixel first part and a second part (SP2-1, SP2-2, SP3-1, SP3-2, SP4-1, SP4-2). Here, the thin-film transistor (T) may be a driving thin-film transistor that generates and supplies data current to the pixel electrode (210) in the first to fourth subpixel first portion (SP1-1, SP2-1, SP3-1, SP4-1) or the first to fourth subpixel second portion (SP1-2, SP2-2, SP3-2, SP4-2).

[0057] Here, the repair pattern (RP) is formed on the same layer as the pixel electrode (210) of the light-emitting element, and may be provided in a structure in which the pixel electrode (210) is extended and branched, or may be provided in a structure formed with a predetermined contact hole and wiring structure.

[0058] Accordingly, when a bright spot occurs in an area corresponding to the first to fourth subpixel first portion (SP1-1, SP2-1, SP3-1, SP4-1) or the first to fourth subpixel second portion (SP1-2, SP2-2, SP3-2, SP4-2) of the electroluminescent display device according to the present specification, by selectively performing a repair process in the repair pattern (RP), one of the first to fourth subpixel first portion (SP1-1, SP2-1, SP3-1, SP4-1) or the first to fourth subpixel second portion (SP1-2, SP2-2, SP3-2, SP4-2) can be operated normally.

[0059] Figure 4 is a cross-sectional view taken along the line I-I' of Figure 2, and Figure 5 is an enlarged view of part B of Figure 4.

[0060] Referring to FIGS. 4 and 5, an electroluminescent display device according to one example of the present specification may include a driving thin-film transistor (T) formed on a substrate (110), a planarization layer (160), a light-emitting element (200), a bank (180), a cathode contact electrode (270), and an auxiliary power line (EVSS).

[0061] An electroluminescent display device according to one embodiment of the present specification may include a substrate (110) comprising a subpixel area (SPA) and a cathode contact area (CCA) located on at least one side of the subpixel area (SPA); an interlayer insulating layer (140) disposed on the substrate (110); an auxiliary electrode (AE) disposed on the interlayer insulating layer (140) and having an upper surface that is exposed at least partially in the cathode contact area (CCA); a protective layer (150) disposed to cover at least a part of the auxiliary electrode (AE); a cathode contact electrode (270) disposed on the protective layer (150); an organic light-emitting layer (230) disposed on the cathode contact electrode (270); and a cathode electrode (250) disposed on the organic light-emitting layer (230). Furthermore, the protective layer (150) overlaps at least partially with the cathode contact area (CCA) and includes a plurality of trench structures (TR) from which the protective layer (150) has been removed.

[0062] An electroluminescent display device according to one example of the present specification may include a transparent region (TA) and a non-transparent region (NTA). The non-transparent region (NTA) may include a light-emitting region (EA) and a non-light-emitting region (NEA) defined by a light-emitting element, a bank (180), and a cathode contact region (CCA) formed adjacent to the transparent region (TA) and in which a cathode electrode (250) and an auxiliary electrode (AE) are in contact. Additionally, in FIG. 4, the light-emitting region (EA) and the left and right sides of the light-emitting region (EA) or the non-light-emitting region (NEA) surrounding the light-emitting region (EA) may be defined as a single sub-pixel region (SPA).

[0063] Here, the substrate (110) may have the same configuration as the substrate (10) described in FIG. 1. Thus, the substrate (110) may be a glass substrate, a thin glass substrate that can be bent or curved, a plastic substrate, or a silicon substrate.

[0064] A driving thin-film transistor (T) may be placed in an active region (AA) on a buffer layer (120) and may be placed to correspond to each subpixel. According to one example, the thin-film transistor (T) may include an active layer (ACT), a gate electrode (GE), a source electrode (SE), and a drain electrode (DE). Here, the thin-film transistor (T) may be a driving thin-film transistor. Additionally, although the thin-film transistor (T) is shown as having a top-gate structure in FIG. 4, the embodiments of this specification are not limited thereto, and various known structures may be applied to the thin-film transistor (T). However, in this specification, a thin-film transistor with a top-gate structure is described as the structure.

[0065] The buffer layer (120) may be disposed on the substrate (110) and the light-blocking layer (LS). According to one example, the buffer layer (120) may be formed by stacking a plurality of inorganic films. For example, the buffer layer (120) may be formed as a multilayer film in which one or more inorganic films selected from silicon oxide (SiOx), silicon nitride (SiN), and silicon oxynitride (SiON) are stacked.

[0066] An active layer (ACT) may be provided on a buffer layer (120). The active layer (ACT) may be arranged to overlap with a gate electrode (GE), a source electrode (SE), and a drain electrode (DE), and the active layer (ACT) may include a channel region and a source / drain region. Furthermore, the channel region of the active layer (ACT) may be formed to overlap with the gate electrode (GE) in the central region of the active layer (ACT), and the source / drain region may be formed side by side with the channel region in between. Additionally, a gate insulating film (130) may be provided between the active layer (ACT) and the gate electrode (GE). Specifically, the gate insulating film (130) may be placed between the channel region of the active layer (ACT) and the gate electrode (GE) to insulate the active layer (ACT) and the gate electrode (GE). The gate electrode (GE) may overlap with the channel region of the active layer (ACT) with the gate insulating film (130) in between. The active layer (ACT) may be formed of a silicon-based semiconductor material or an oxide-based semiconductor material.

[0067] The gate insulating film (130) may be provided on the active layer (ACT) and may be disposed on the buffer layer (120). Additionally, the gate insulating film (130) may insulate the active layer (ACT) and the gate electrode (GE). The gate insulating film (130) may include a silicon nitride film (SiNx) or a silicon oxide film (SiO2), but is not limited thereto.

[0068] A gate electrode (GE) may be provided on the gate insulating film (130). The gate electrode (GE) may be formed as a single layer or multiple layers made of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

[0069] An interlayer insulating layer (140) may be provided on a gate electrode (GE) and a gate insulating film (130). The interlayer insulating layer (140) may perform the function of protecting a thin-film transistor (T). The interlayer insulating layer (140) may have a corresponding region removed to allow contact between the active layer (ACT) and the source electrode (SE) or between the active layer (ACT) and the drain electrode (DE). For example, the interlayer insulating layer (140) may include a contact hole exposing a source region of the active layer (ACT) that contacts the source electrode (SE) and a contact hole exposing a drain region of the active layer (ACT) that contacts the drain electrode (DE). Additionally, the interlayer insulating layer (140) may be formed on top of the gate insulating film (130). According to one example, the interlayer insulating layer (140) may include a silicon oxide film (SiO2) or a silicon nitride film (SiN), or the interlayer insulating layer (140) may be composed of a plurality of layers including a silicon oxide film (SiO2) and a silicon nitride film (SiN).

[0070] According to one example of the present specification, the source electrode (SE) and drain electrode (DE) may be formed of a single layer made of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), silver (Ag), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof, a single layer made of a transparent conductive oxide (TCO) such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide), or a multilayer thereof. In the present specification, the source electrode (SE) and drain electrode (DE) may be made of materials selected to satisfy the specific electrical characteristics required by the thin-film transistor (T).

[0071] Additionally, a light-blocking layer (LS) disposed below the active layer (ACT) of the thin-film transistor (T) may be further included. The light-blocking layer (LS) may be disposed on the substrate (110) so as to overlap with the thin-film transistor (T). For example, the light-blocking layer (LS) may be formed by depositing a metal layer on the substrate (110) and then performing patterning. The light-blocking layer (LS) may be a single film or a multilayer film made of metals such as molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu), and silver (Ag), or alloys thereof, but is not limited thereto and may be implemented with various materials known in the art. Furthermore, the light-blocking layer (LS) may include a lower light-blocking layer and an upper light-blocking layer.

[0072] A protective layer (150) may be provided on an interlayer insulating layer (140), a source electrode (SE), and a drain electrode (DE). The protective layer (150) may perform the function of protecting the source electrode (SE) and the drain electrode (DE). The protective layer (150) may include a contact hole that exposes the source electrode (SE) or the drain electrode (DE). Here, the contact hole of the protective layer (150) may be connected to a contact hole of the flattening layer (160) so that the pixel electrode (210) can contact the source electrode (SE). The protective layer (150) may include a silicon oxide film (SiO2) or a silicon nitride film (SiN).

[0073] The protective layer (150) may include a first contact hole (CH1) and a trench structure (TR) for a contact structure between a cathode contact electrode (270) and an auxiliary electrode (AE) in a cathode contact area (CCA) or a sub-pixel area (SPA). The first contact hole (CH1) may be formed to overlap with at least a portion of the non-emissive area (NEA) of the sub-pixel area (SPA). Additionally, the trench structure (TR) may be formed to overlap with the cathode contact area (CCA). At this time, the first contact hole (CH1) and the trench structure (TR) may each be provided in a form that completely removes the protective layer (150) in the thickness direction. Accordingly, a stable contact structure between the cathode contact electrode (270) and the auxiliary electrode (AE) can be provided through the first contact hole (CH1) and the trench structure (TR) formed in the protective layer (150).

[0074] A planarization layer (160) may be disposed on a substrate (110). The planarization layer (160) may be formed to overlap the light-emitting region (EA) of the active region (AA) and to overlap at least partially with the non-light-emitting region (NEA). The planarization layer (160) may overlap the light-emitting region (EA) of the active region (AA) so that the light-emitting region (EA) defined by the light-emitting element (200) and the bank (180) is formed substantially flat. Additionally, the planarization layer (160) may be formed to overlap at least partially with the non-light-emitting region (NEA). The planarization layer (160) may be formed from an organic film such as an acrylic resin, an epoxy resin, a phenolic resin, a polyamide resin, and a polyimide resin.

[0075] A light-emitting element (200) may be disposed on a planarization layer (160). The light-emitting element (200) may include a pixel electrode (210), an organic light-emitting layer (230), and a cathode electrode (250). Additionally, the light-emitting element (200) may be electrically connected to a thin-film transistor (T). Specifically, the pixel electrode (210) of the light-emitting element (200) may be in contact with the source electrode (SE) of the thin-film transistor (T) through a contact hole formed in at least a portion of the planarization layer (160) and the protective layer (150).

[0076] A pixel electrode (210) is provided on a planarization layer (160) and can be electrically connected to a source electrode (SE) of a thin-film transistor (T). The pixel electrode (210) can be contacted to the source electrode (SE) of the thin-film transistor (T) through a contact hole provided in the planarization layer (160). Additionally, the pixel electrode (210) according to an example of the present specification may include a metallic material or a transparent conductive oxide. For example, the pixel electrode (210) may be formed from a highly reflective metallic material such as a stacked structure of aluminum and titanium (Ti / Al / Ti), a stacked structure of aluminum and indium tin oxide (ITO / Al / ITO), an Ag alloy, and a stacked structure of an Ag alloy and ITO (ITO / Ag alloy / ITO). Here, the Ag alloy may be an alloy of silver (Ag), palladium (Pd), and copper (Cu), and may be referred to as an APC alloy.

[0077] According to one example of the present specification, a light-emitting element (200) may include a pixel electrode (210) formed on a planarization layer (160) and formed on at least a portion of an active region (AA) on a substrate (110), a cathode electrode (250) formed opposite to the pixel electrode (210) and formed to overlap the entire active region (AA), and a light-emitting layer (230) formed between the pixel electrode (210) and the cathode electrode (250) and formed to correspond to a pixel. Additionally, the light-emitting layer (230) and the cathode electrode (250) may be formed to overlap at least a portion of an inactive region (IA) adjacent to the active region (AA) according to the preparation method of the layer, but are not limited thereto.

[0078] The cathode contact electrode (270) may be formed to overlap with the cathode contact region (CCA) and located in at least a portion of the non-emissive region (NEA) surrounding the emitting region (EA). The cathode contact electrode (270) may be formed to overlap with at least a portion of the sidewall of the flattening layer (160) and may be provided in a form that extends and protrudes into the cathode contact region (CCA) while covering the protective layer (150). Accordingly, the protective layer (150) is not formed in the lower portion of the area where the cathode contact electrode (270) protrudes beyond the protective layer (150), thereby providing an undercut (UC) structure. This undercut (UC) structure may be provided so that its upper surface is exposed for contact between the auxiliary electrode (AE) and the cathode electrode (250).

[0079] At this time, the auxiliary electrode (AE) and the cathode contact electrode (270) can be connected through the first contact hole (CH1) of the protective layer (150) formed in the area where the non-luminescent region (NEA) and the auxiliary electrode (AE) overlap. Additionally, the protective layer (150) may include a plurality of trench structures (TR: TR1, TR2, TR3) formed in the area where the cathode contact region (CCA) and the auxiliary electrode (AE) overlap. The trench structures (TR) may include a first trench structure (TR1), a second trench structure (TR2), and a third trench structure (TR3). In FIGS. 4 and 5, the trench structure (TR: TR1, TR2, TR3) is indicated as referring to one side of the etched and removed area of ​​the protective layer (150), but the trench structure (TR: TR1, TR2, TR3) may mean that it includes not only one side of the etched area of ​​the protective layer (150) but also the bottom surface and the other side facing the one side.

[0080] In FIGS. 4 and 5, the trench structure (TR) is illustrated as comprising a first trench structure (TR1), a second trench structure (TR2), and a third trench structure (TR3), but embodiments of the trench structure (TR) of this specification are not limited thereto. A trench structure according to one example of this specification may be provided to include a plurality of dense trench structures to provide a longer permeable path or barrier structure. Additionally, although the trench structure (TR) in FIGS. 4 and 5 is illustrated in an angular shape, not only an angular shape but also a certain rounded structure, a tapered structure, or an inverse tapered structure may be applied.

[0081] The auxiliary electrode (AE) and the cathode contact electrode (270) can be contacted through the first contact hole (CH1). Additionally, the auxiliary electrode (AE) and the cathode contact electrode (270) can also be contacted through a plurality of trench structures (TR: TR1, TR2, TR3). Accordingly, an electroluminescent display device according to an example of the present specification can provide a structure in which the cathode contact electrode (270) and the auxiliary electrode (AE) can be stably contacted.

[0082] As illustrated in FIG. 4, a cathode contact electrode (270) according to one example of the present specification may be positioned so as to be spaced apart from a pixel electrode (210) on one side. Furthermore, the cathode contact electrode (270) may be prepared with the same material and the same process as the pixel electrode (210) and may have the same stacked structure. Accordingly, the cathode contact electrode (270) may be formed from a highly reflective metallic material such as a stacked structure of aluminum and titanium (Ti / Al / Ti), a stacked structure of aluminum and ITO (ITO / Al / ITO), an Ag alloy, and a stacked structure of Ag alloy and ITO (ITO / Ag alloy / ITO). Here, the Ag alloy may be an alloy of silver (Ag), palladium (Pd), and copper (Cu), and may be referred to as an APC alloy.

[0083] Here, the same material and the same process can be defined as proceeding as a single process and distinguished by a mask pattern process. The same definition may also apply to the expressions of the same material and the same process described below.

[0084] A light-emitting layer (230) may be provided on a pixel electrode (210) and a cathode contact electrode (270). According to one example of the specification, the light-emitting layer (230) may not be formed to correspond individually to an active area (AA) or a light-emitting area (EA) of a subpixel, but may be formed to be common to the entire pixel of the active area (AA), including a transparent area (TA) and a non-transparent area (NTA). Additionally, the light-emitting layer (230) may be formed on at least a portion of an inactive area (IA) adjacent to the active area (AA). Specifically, it may be arranged to overlap with a bank (180) located at the boundary between the active area (AA) and the inactive area (IA).

[0085] At this time, when the light-emitting layer (230) is formed in a plurality of trench structures (TR) formed in the protective layer (150) of the cathode contact region (CCA), at least a portion of the light-emitting layer (230) may have a disconnected structure or a discontinuous structure. Here, the disconnected structure or discontinuous structure may be defined as a physically separated and spaced-out structure. Accordingly, the light-emitting layer (230) may have a physically disconnected structure or a discontinuous structure by the plurality of trench structures (TR).

[0086] Additionally, although the light-emitting layer (230) is depicted as having a physically disconnected or discontinuous structure in FIGS. 4 and 5, it may be formed as a continuous structure in the region where the light-emitting layer (230) overlaps with the trench structure (TR). However, even in this case, the reliability of moisture penetration of the electroluminescent display device can be improved due to the effect of extending the moisture penetration path (P). As shown in FIG. 5, the light-emitting layer (230) may have a disconnected structure in which the moisture penetration path is formed discontinuously in the region where the trench structure (TR) is formed. In this way, the moisture penetration path can be blocked by the disconnected structure of the light-emitting layer (230). Therefore, the reliability of the fade-out of the subpixel of the electroluminescent display device can be improved.

[0087] Specifically, the light-emitting layer (230) can be formed based on a deposition process and overlaps with the pixel electrode (210) and can be formed up to a predetermined area including the bank (180). For example, the light-emitting layer (230) can be formed at the boundary between the active area (AA) and the inactive area (IA), and within the active area (AA), it can be formed across the entire active area (AA) based on a predetermined step coverage characteristic, and the process can be controlled so that it is not formed in at least a part of the cathode contact area (CCA).

[0088] According to one example, the light-emitting layer (230) may include a hole transporting layer, a color light-emitting layer, and an electron transporting layer. In this case, when voltage is applied to the pixel electrode (210) and the cathode electrode (250), holes and electrons move to the color light-emitting layer through the hole transporting layer and the electron transporting layer, respectively, and combine with each other in the color light-emitting layer to emit light. According to one example, the light-emitting layer (230) may further include at least one functional layer to improve light emission efficiency and lifespan. The color light-emitting layer of the light-emitting layer (230) may emit blue, red, green, or white light. However, it is not limited thereto. Depending on the light-emitting material, the color light-emitting layer may emit a color in which at least two colors among blue, red, and green are mixed.

[0089] A cathode electrode (250) may be provided on the light-emitting layer (230). The cathode electrode (250) may be implemented in the form of an electrode common to the active region (AA). According to one example, the cathode electrode (250) may be made of a transparent conductive oxide (TCO), such as Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO), but is not limited thereto.

[0090] The cathode electrode (250) is formed based on a deposition process similar to the light-emitting layer (230), but due to the characteristics of the inorganic film, it may have a higher step coverage characteristic than the light-emitting layer (230), and in the active region (AA), it is formed in all regions that overlap with the light-emitting layer (230), and in all regions except for a part of the undercut (UC) of the cathode contact region (CCA).

[0091] Additionally, as described above, if the light-emitting layer (230) is formed as a discontinuous or disconnected structure in the region where it overlaps with a plurality of trench structures (TR), the cathode electrode (250) can make contact with the cathode contact electrode (270) in the region where the light-emitting layer (230) is not formed. Accordingly, the display device according to the embodiment of the present specification can provide a structure that enables stable contact between the cathode electrode (250) and the cathode contact electrode (270) in the cathode contact region (CCA).

[0092] The cathode electrode (250) may be provided in the transmission region (TA) as shown in FIG. 4, but is not necessarily limited thereto. The cathode electrode (250) may be provided only in the non-transmission region (NTA) including the light-emitting region (EA), and may not be provided in the transmission region (TA) to improve transmittance.

[0093] The cathode electrode (250) may be a common layer formed in common to the subpixels (SP1, SP2, SP3, SP4) to apply the same voltage. The cathode electrode (250) may be formed of a transparent conductive material (TCO) such as indium tin oxide (ITO) or indium zinc oxide (IZO) that can transmit light, or a semi-transmissive conductive material such as magnesium (Mg), silver (Ag), or an alloy of magnesium (Mg) and silver (Ag).

[0094] The auxiliary electrode (AE) can be formed to provide individual contact with each of the cathode electrodes (250) of a plurality of subpixels. As shown in FIG. 4, the auxiliary electrode (AE) can provide indirect contact through contact between the cathode electrode (250) of the light-emitting element (200) formed on one side with respect to the cathode contact area (CCA) and the cathode contact electrode (270). Additionally, the auxiliary electrode (AE) can provide direct contact with the cathode electrode (250) of the transmission area (TA) formed on the other side with respect to the cathode contact area (CCA) at the cathode contact area (CCA). Furthermore, since the cathode electrode (250) is provided as a common electrode as described above, the cathode electrode (250) formed in the active area (AA) can be in contact with the auxiliary electrode (AE) at a plurality of cathode contact areas (CCA).

[0095] As described above, the cathode contact region (CCA) is a region provided in the non-transparent region (NTA), adjacent to the transparent region (TA), and may be provided adjacent to at least one plurality of sub-pixel regions (SP1, SP2, SP3, SP4). Specifically, the cathode contact region (CCA) may be defined as a predetermined region comprising a region in which at least a portion of the protective layer (150) is removed and an auxiliary electrode (AE) is exposed for contact with the cathode electrode (250), and a region in which the auxiliary electrode (AE) is in contact with the cathode contact electrode (270).

[0096] Here, contact between the cathode contact electrode (270) and the auxiliary electrode (AE) can be made through a contact hole (CH1) formed in at least a portion of the protective layer (150) adjacent to the cathode contact area (CCA).

[0097] The first power link wiring (62) described above in FIG. 1 may have the same configuration as the auxiliary power line (EVSS) and auxiliary electrode (AE). Although the first power link wiring (62) is shown as a single wiring due to the constraints of the illustration in FIG. 1, it may be composed of the auxiliary power line (EVSS) and auxiliary electrode (AE), and a uniform resistance may be applied to the cathode electrode (250) across the entire active region (AA).

[0098] The auxiliary power line (EVSS) can be electrically connected to the auxiliary electrode (AE). The auxiliary power line (EVSS) may contain the same material as the light-blocking layer (LS) and may have the same laminated structure. Additionally, the auxiliary power line (EVSS) may be placed on the substrate (110). Accordingly, the auxiliary power line (EVSS) may be formed as a single film or a multilayer film made of metals such as molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu), and silver (Ag), or alloys thereof, but is not limited thereto and may be implemented with various materials known in the art.

[0099] The auxiliary electrode (AE) can be contacted with an auxiliary power line through a second contact hole (CH2) formed in at least a portion of the interlayer insulating layer (140). Here, the second contact hole (CH2) can be provided such that at least a portion of the buffer layer (120) is removed as needed.

[0100] The auxiliary electrode (AE) can be spaced apart from the source electrode (SE) and the drain electrode (DE) on the interlayer insulating layer (140). The auxiliary electrode (AE) can be formed with the same material and the same process as the source electrode (SE) and the drain electrode (DE), and can have the same stacked structure. Accordingly, the auxiliary electrode (AE) can be formed as a single layer made of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), silver (Ag), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof, as a single layer made of a transparent conductive oxide (TCO) such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide), or as a multilayer thereof.

[0101] Additionally, the auxiliary electrode (AE) can be electrically connected to the cathode contact electrode (270) through the first contact hole (CH1) provided in the protective layer (150).

[0102] According to one example of the present specification, the flattening layer (160) may include a contact hole through which each of the pixel electrode (210) and the cathode contact electrode (270) passes. Here, the contact hole of the flattening layer (160) may be connected to the contact hole of the protective layer (150) so that the pixel electrode (210) can contact the source electrode (SE). For example, the flattening layer (160) may include organic materials such as photoacryl and polyimide.

[0103] A bank (180) can define a light-emitting region (EA) for each of the subpixels (SP1, SP2, SP3, SP4). A light-emitting region (EA) for each of the subpixels (SP1, SP2, SP3, SP4) represents a region in which a pixel electrode (210), an organic light-emitting layer (230), and a cathode electrode (250) are sequentially stacked, and holes from the pixel electrode (210) and electrons from the cathode electrode (250) combine with each other in the organic light-emitting layer (230) to emit light. In this case, the region where the bank (180) is formed does not emit light and thus becomes a non-light-emitting region (NEA), and the region where the bank (180) is not formed and the pixel electrode (210) is exposed can become a light-emitting region (EA). Additionally, the bank (180) can be formed to cover the edge of the pixel electrode (210) and expose a part of the pixel electrode (210). Accordingly, the bank (180) can prevent the problem of reduced light emission efficiency caused by current concentration at the end of the pixel electrode (210).

[0104] Bank (180) can be formed from an organic film such as acrylic resin, epoxy resin, phenolic resin, polyamide resin, and polyimide resin.

[0105] The bank (180) can cover at least a portion of the upper surface of the pixel electrode (210) and the cathode contact electrode (270). Thus, the bank (180) is positioned between a plurality of pixel electrodes (210) and cathode contact electrodes (270) to electrically insulate adjacent pixel electrodes (210) and cathode contact electrodes (270).

[0106] The encapsulation portion (170) can cover a transparent region (TA) and a non-transparent region (NTA), and can cover at least a portion of an inactive region (IA). According to one example of the specification, the encapsulation portion (170) may have a thin film encapsulation structure comprising at least one inorganic film and at least one organic film, wherein the inorganic film and the organic film are alternately arranged. The encapsulation portion (170) can prevent moisture or oxygen from penetrating into the light-emitting element (200). For example, the encapsulation portion (170) may include a first encapsulation portion (171), a second encapsulation portion (172), and a third encapsulation portion (173) that are sequentially stacked. Furthermore, the first encapsulation portion (171) and the third encapsulation portion (173) may be inorganic films, and the second encapsulation portion (172) may be an organic film, but is not limited thereto.

[0107] Additionally, as illustrated in FIG. 5, the first sealing portion (171) may be provided in an unfilled form in the undercut (UC) according to the shape of the cathode contact area (CCA) and may have a structure that is partially disconnected from the cathode contact area (CCA). Accordingly, it may be provided in a form where a certain void exists in the undercut (UC). Furthermore, the first sealing portion (171) may be provided not only in a disconnected structure as in FIG. 5 but also in a connected structure, which is considered to be included within the scope of the invention of this specification.

[0108] Additionally, the first encapsulation portion (171) and the third encapsulation portion (173) may include a silicon nitride film (SiNx) or a silicon oxide film (SiNx), but are not limited thereto. The second encapsulation portion (172) may be an organic material including resin, but is not limited thereto.

[0109] An electroluminescent display device according to one example of the present specification, to which the structure of the cathode contact region (CCA) described above is applied, may not exhibit a fade-out phenomenon of subpixels adjacent to the cathode contact region (CCA) even when exposed to experiments in a harsh environment of a temperature of 85°C and a relative humidity of 85%.

[0110] Although the embodiments of this specification have been described in more detail with reference to the attached drawings, this specification is not necessarily limited to these embodiments and may be modified in various ways within the scope of the technical spirit of this specification. Accordingly, the embodiments disclosed in this specification are intended to explain, not limit, the technical spirit of this specification, and the scope of the technical spirit of this specification is not limited by these embodiments. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. The scope of protection of this specification shall be interpreted by the claims, and all technical spirits within an equivalent scope shall be interpreted as being included within the scope of rights of this specification. Explanation of the symbols

[0112] AA: Active area IA: Inactive area 1: Display panel 3: Panel driving circuit 60: 1st power wiring 70: 2nd power wiring 10, 110: Substrate T: Driving thin-film transistor CCA: Cathode contact region 200: Light-emitting element 210: Pixel electrode 230: Organic light-emitting layer 250: Cathode electrode 270: Cathode contact electrode LP: Auxiliary Power Contact Pad EVSS: Auxiliary Power Line TR: Trench structure UC: Undercut

Claims

Claim 1 An electroluminescent display device comprising: a substrate including a transparent region and a non-transparent region; an interlayer insulating layer disposed on the substrate, wherein the non-transparent region includes a subpixel region and a cathode contact region having an undercut structure located on at least one side of the subpixel region; an auxiliary electrode disposed on the interlayer insulating layer and having an upper surface that is exposed in at least a portion of the cathode contact region; a protective layer disposed to cover at least a portion of the auxiliary electrode; a cathode contact electrode disposed on the protective layer; a light-emitting layer disposed on the cathode contact electrode; and a cathode electrode disposed on the light-emitting layer, wherein the cathode contact region includes a plurality of trench structures in which a portion of the protective layer and the light-emitting layer is removed. Claim 2 An electroluminescent display device according to claim 1, wherein the light-emitting layer has a discontinuous structure in at least a portion that overlaps with the trench structure. Claim 3 An electroluminescent display device according to claim 1, wherein the cathode contact electrode is in contact with the auxiliary electrode through the portion in which the protective layer is removed in the trench structure. Claim 4 An electroluminescent display device according to claim 1, wherein the cathode electrode is in contact with the cathode contact electrode through the portion in which the light-emitting layer is removed in the trench structure. Claim 5 An electroluminescent display device according to claim 1, wherein the protective layer is formed on one side of the trench structure and includes a first contact hole formed by removing the protective layer, and the cathode contact electrode is in contact with the auxiliary electrode through the first contact hole. Claim 6 An electroluminescent display device according to claim 1, further comprising an auxiliary power line that overlaps at least a portion with the sub-pixel area. Claim 7 In claim 6, the electroluminescent display device wherein the auxiliary electrode is in contact with the auxiliary power line through a second contact hole formed in at least a part of the interlayer insulating layer. Claim 8 An electroluminescent display device according to claim 6, further comprising: a thin-film transistor disposed in the sub-pixel area; and a light-blocking layer disposed below the thin-film transistor and arranged to be spaced apart from the auxiliary power line, wherein the auxiliary power line comprises the same material as the light-blocking layer. Claim 9 An electroluminescent display device according to claim 8, further comprising: a planarization layer disposed on at least a portion of the subpixel area and disposed on the thin-film transistor; and a pixel electrode disposed on the planarization layer. Claim 10 In claim 9, the electroluminescent display device wherein the pixel electrode comprises the same material as the cathode contact electrode. Claim 11 An electroluminescent display device according to claim 8, wherein the thin-film transistor comprises an active layer, a gate electrode, a source electrode, and a drain electrode, and the auxiliary electrode comprises the same material as the source electrode and the drain electrode. Claim 12 delete

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