electroluminescent display device

Abstract

To provide an electroluminescent display device with a bezel width reduced and improved reliability.SOLUTION: An electroluminescent display device includes a substrate 101 including a display region and a non-display region outside the display region, a flattened layer 105 disposed on the substrate and extending from the display region to the non-display region, a bank 106 disposed on the flattened layer extending in the non-display region, an organic layer 152 disposed on the bank, a cathode 153 disposed on the organic layer, a capping layer 120 disposed on the cathode, a trench pattern 180 formed in the non-display region, where the capping layer, the cathode, and the organic layer are removed, and a step difference relieving layer 190 that fills the trench pattern and flattens an upper part of the trench pattern. The capping layer disposed adjacent to the trench pattern is depressed inward relative to the cathode.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an electroluminescent display device, and more particularly to an electroluminescent display device having a narrow bezel. [Background technology]

[0002] As we enter a full-fledged information age, the field of display devices that visually display electrical information signals is rapidly developing, and research is ongoing to develop various display devices with improved performance, such as thinner, lighter, and lower power consumption.

[0003] Representative display devices include a liquid crystal display device (LCD), an electro-wetting display device (EWD), and an organic light emitting display device (OLED).

[0004] Among these, electroluminescent displays (ELDs), including organic light-emitting displays (OLEDs), are self-emitting displays that, unlike LCDs, do not require a separate light source and can be manufactured in a lightweight and thin form. Furthermore, ELDs are advantageous in terms of power consumption due to their low voltage operation, and also have excellent color realization, response speed, viewing angle, and contrast ratio (CR), making them expected to be used in a variety of fields. Summary of the Invention [Problem to be solved by the invention]

[0005] Currently, in electroluminescent displays, a minimum bezel distance is required to ensure reliability such as moisture prevention, and this can be called a reliable bezel. A reliable bezel can be defined as the distance from the edge of the upper substrate (encapsulation substrate) to the edge of the cathode.

[0006] Meanwhile, along with the demand for slimmer display devices, there is also an increasing demand for slimmer non-display areas of display devices, excluding the display area where images are displayed. However, because the cathode must be formed to cover the organic layer to prevent mass production defects due to exposure of the organic layer, there is a limit to ensuring a reliable bezel. That is, when the organic layer and cathode are formed by deposition, a shadow area of ​​a certain length occurs depending on the gap between the deposition mask and the substrate and the deposition method, which limits the reduction of the bezel. In addition, the position and length of the shadow area are non-uniform due to process deviations, resulting in variations in the reliability of the bezel between products, resulting in non-uniform quality.

[0007] Therefore, an object of the present invention is to provide an electroluminescent display device capable of reducing the bezel width by arranging a trench pattern in the shadow region and converting it into a reliable bezel region.

[0008] Another object of the present invention is to provide an electroluminescent display device having improved reliability by improving the lift-up phenomenon of a cathode adjacent to a trench pattern.

[0009] Another object of the present invention is to provide an electroluminescent display device having an improved rigidity and heat dissipation effect of a display panel.

[0010] The objects of the present invention are not limited to those mentioned above, and other objects not mentioned above will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0011] In order to solve the above-mentioned problems, an electroluminescent display device according to one embodiment of the present invention includes a substrate including a display area and a non-display area outside the display area, a planarization layer disposed on the substrate and extending from the display area to the non-display area, a bank disposed on the planarization layer extending to the non-display area, an organic layer disposed on the bank, a cathode disposed on the organic layer, a capping layer disposed on the cathode, a trench pattern disposed in the non-display area from which the capping layer, the cathode, and the organic layer have been removed, and a step reduction layer that fills the trench pattern and planarizes an upper portion of the trench pattern, and the capping layer disposed adjacent to the trench pattern may be recessed inward compared to the cathode.

[0012] Further details of the embodiments are included in the detailed description and drawings.

[0013] The present invention can improve the reliability of moisture barrier performance while reducing the bezel width by forming a trench pattern in which a portion of the cathode and organic layer is removed in the unnecessary shadow area generated by using a deposition mask.

[0014] Even if a lift-up phenomenon occurs in which a portion of a cathode disposed in an area adjacent to a trench pattern is separated from an organic layer due to laser irradiation, the present invention can improve the reliability of an electroluminescent display device by depositing a step reduction layer on the upper portion to fill the separation space.

[0015] The present invention provides a multilayer structure encapsulation structure including a relatively thick reinforcing substrate, thereby ensuring sufficient rigidity and heat dissipation. In addition, the step mitigation layer filling and covering the trench pattern improves adhesion of the multilayer structure encapsulation structure and thereby improves durability of the electroluminescent display device.

[0016] The effects of the present invention are not limited to the above-mentioned examples, and various other effects are included within the scope of the present invention. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a plan view schematically illustrating an electroluminescence display device according to a first embodiment of the present invention. [Figure 2] 1 is a cross-sectional view showing a sub-pixel of an electroluminescent display device according to a first embodiment of the present invention. [Figure 3] FIG. 2 is a cross-sectional view taken along II' in FIG. [Figure 4a] This is a focused ion beam (FIB) image of area A in Figure 3. [Figure 4b] This is a focused ion beam (FIB) image of area A in Figure 3. [Figure 4c] This is a focused ion beam (FIB) image of area A in Figure 3. [Figure 5a] This is a FIB image of area A in Figure 3 viewed from above. [Figure 5b] This is a FIB image of area A in Figure 3 viewed from above. [Figure 5c] This is a FIB image of area A in Figure 3 viewed from above. [Figure 6] 1 is a graph showing transmittance as a function of wavelength for a capping layer, an organic layer, a cathode, and a triplex film according to some aspects of the present invention. [Figure 7] 1 is a table showing transmittance by laser wavelength for a capping layer, an organic layer, a cathode, and a triplex according to some aspects of the present invention. [Figure 8] FIG. 10 is a cross-sectional view showing a display panel according to a second embodiment of the present invention. [Figure 9] FIG. 10 is a cross-sectional view showing a display panel according to a third embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional view showing a display panel according to a fourth embodiment of the present invention. [Figure 11] FIG. 10 is a cross-sectional view showing a display panel according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] The advantages and features of the present invention, and methods for achieving them, will become apparent from the following detailed description of the embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and may be embodied in various different forms. These embodiments are provided solely to ensure that this disclosure will be complete and will fully convey the scope of the invention to those skilled in the art. The present invention is defined solely by the scope of the claims.

[0019] The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for illustrating the embodiments of the present invention are merely illustrative, and the present invention is not limited to the illustrated details. Furthermore, when describing the present invention, if a detailed description of related prior art is deemed to unnecessarily obscure the gist of the present invention, such a detailed description will be omitted. Furthermore, when using words such as "include," "have," and "be made" in this specification, other parts may be added unless "only" is used. When a component is expressed in the singular, it also includes the plural unless otherwise explicitly stated.

[0020] When interpreting elements, they are interpreted as including a margin of error even if there is no other explicit description.

[0021] When describing a positional relationship, for example, when describing the positional relationship of two parts using "above," "at the top," "below," "next to," etc., one or more other parts may be located between the two parts, as long as "immediately" or "directly" is not used.

[0022] When an element or layer is referred to as being on another element or layer, this includes the case where the element or layer is directly on the other element or layer, or where there are other layers or elements interposed therebetween.

[0023] 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. Therefore, a first component referred to below may be a second component within the technical concept of the present invention.

[0024] Like reference numbers refer to like elements throughout the specification.

[0025] The size and thickness of each component shown in the drawings are shown for convenience of explanation, and the present invention is not necessarily limited to the size and thickness of the components shown.

[0026] The features of the various embodiments of the present invention may be partially or fully combined or combined with each other, and various technical interlocking and driving mechanisms are possible, as will be fully understood by those skilled in the art. Each embodiment may be implemented independently of the others, or may be implemented together in a related relationship.

[0027] Various embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0028] FIG. 1 is a plan view schematically illustrating an electroluminescent display device according to a first embodiment of the present invention.

[0029] Referring to FIG. 1, the electroluminescent display device according to the first embodiment of the present invention may include a display panel 100, a flexible film 160, a printed circuit board 170, and a trench pattern 180.

[0030] The display panel 100 is a panel for displaying images to a user.

[0031] The display panel 100 may include display elements for displaying images, driving elements for driving the display elements, and wiring for transmitting various signals to the display elements and driving elements. The display elements may be defined differently depending on the type of the display panel 100. For example, if the display panel 100 is an organic light-emitting display panel, the display elements may be organic light-emitting elements including an anode, an organic layer, and a cathode. For example, if the display panel 100 is a liquid crystal display panel, the display elements may be liquid crystal display elements.

[0032] In the following, it is assumed that the display panel 100 is an organic light-emitting display panel, but the display panel 100 is not limited to an organic light-emitting display panel.

[0033] The display panel 100 can include a display area AA and a non-display area NA.

[0034] The display area AA is an area where the display panel 100 displays an image.

[0035] The display area AA may include a plurality of subpixels constituting a plurality of pixels and a circuit for driving the subpixels. The subpixels are the smallest units constituting the display area AA, and a display element may be disposed in each of the subpixels, constituting a pixel. For example, each of the subpixels may include, but is not limited to, an organic light-emitting element including an anode, an organic layer, and a cathode. The circuit for driving the subpixels may include, but is not limited to, a driving element and wiring. For example, the circuit may include, but is not limited to, a thin film transistor, a storage capacitor, a gate wiring, a data wiring, etc.

[0036] The non-display area NA is an area where no video is displayed.

[0037] In FIG. 1, the non-display area NA is shown surrounding the rectangular display area AA, but the shapes and arrangements of the display area AA and the non-display area NA are not limited to the example shown in FIG.

[0038] In other words, the display area AA and the non-display area NA may have a shape suitable for the design of an electronic device equipped with an electroluminescent display device. For example, exemplary shapes of the display area AA may be pentagonal, hexagonal, circular, elliptical, etc.

[0039] Various wirings and circuits for driving the organic light emitting elements in the display area AA may be arranged in the non-display area NA, for example, link wirings for transmitting signals to the sub-pixels and circuits in the display area AA or driving ICs such as gate driver ICs and data driver ICs may be arranged in the non-display area NA, but are not limited thereto.

[0040] The electroluminescent display device may include various additional elements for generating various signals or driving pixels in the display area AA. Additional elements for driving pixels may include an inverter circuit, a multiplexer, an electrostatic discharge (ESD) circuit, etc. The electroluminescent display device may also include additional elements associated with functions other than driving pixels. For example, the electroluminescent display device may further include additional elements providing a touch sensing function, a user authentication function (e.g., fingerprint recognition), a multi-level pressure sensing function, a tactile feedback function, etc. The aforementioned additional elements may be located in the non-display area NA and / or an external circuit connected to the connection interface.

[0041] The flexible film 160 is a film in which various components are disposed on a flexible base film. Specifically, the flexible film 160 is a film for supplying signals to a plurality of sub-pixels and circuits in the display area AA, and may be electrically connected to the display panel 100. The flexible film 160 is disposed at one end of the non-display area NA of the display panel 100, and may supply power voltages, data voltages, etc. to the plurality of sub-pixels and circuits in the display area AA. The number of flexible films 160 may vary depending on the design and is not limited thereto.

[0042] Meanwhile, driving ICs such as gate driver ICs and data driver ICs may be disposed on the flexible film 160. The driving ICs are components that process data for displaying images and driving signals for processing the data. Depending on the mounting method, the driving ICs may be disposed in a chip-on-glass (COG), chip-on-film (COF), tape carrier package (TCP), or other manners.

[0043] The printed circuit board 170 may be disposed at one end of the flexible film 160 and connected to the flexible film 160. The printed circuit board 170 is a component that supplies signals to the driving IC. The printed circuit board 170 may also supply various signals, such as driving signals and data signals, to the driving IC. For example, a data driver that generates data signals may be mounted on the printed circuit board 170, and the generated data signals may be supplied to a plurality of sub-pixels and circuits of the display panel 100 through the flexible film 160. The number of printed circuit boards 170 may vary depending on the design and is not limited thereto.

[0044] On the other hand, a minimum bezel distance is required in electroluminescent displays to ensure reliability such as moisture prevention, and in line with the demand for slimmer display devices, there is also an increasing demand for slimmer non-display areas NA of display devices excluding the display area AA where images are displayed. However, there is a limit to how much the bezel can be reduced because a shadow area occurs due to the gap between the mask and the substrate during deposition of the cathode and organic layers.

[0045] Therefore, the first embodiment of the present invention is characterized in that a trench pattern 180, in which a portion of the cathode and organic layer is removed, is disposed in the shadow region within the non-display area NA. That is, in the first embodiment of the present invention, the trench pattern 180 can slow the rate of moisture penetration into the side surfaces of the display panel 100. Also, by converting the existing shadow region into a reliable bezel region L in this way, the bezel width can be reduced.

[0046] In this case, the trench pattern 180 may be formed across the non-display area NA on three sides of the display panel 100 excluding one side on which the flexible film 160 is disposed. That is, as shown in Fig. 1, the trench pattern 180 may be formed across three sides of the display panel 100, namely, the left, right, and top, on which the flexible film 160 is not disposed, among the four sides of the display panel 100, but is not limited thereto. Referring to Fig. 1, the trench pattern 180 may not be formed on the bottom side of the display panel 100 because there is a risk of damage due to laser irradiation due to the arrangement of driving ICs and voltage application, but is not limited thereto.

[0047] The trench pattern 180 can be formed by removing the cathode and organic layers in the shadow area outside the display area AA through, for example, laser ablation, so that the reliable bezel area L can be expanded and the bezel width can be reduced by the length of the added reliable bezel area L.

[0048] A more detailed description of the trench pattern 180 will be provided with reference to FIGS.

[0049] FIG. 2 is a cross-sectional view showing a sub-pixel of an electroluminescent display device according to a first embodiment of the present invention.

[0050] FIG. 3 is a cross-sectional view taken along II' in FIG.

[0051] Fig. 2 is a cross-sectional view of one sub-pixel in a display panel 100 according to a first embodiment of the present invention. Fig. 3 shows a cross-section of the left side of the side of the display panel 100 on which a trench pattern 180 is formed. For ease of explanation, Fig. 3 schematically shows a pixel portion 115 in the display area AA and a GIP portion 125 in the non-display area NA.

[0052] 2 and 3, a display panel 100 according to a first embodiment of the present invention may have driving elements 110 disposed on a substrate 101.

[0053] A planarization layer 105 may then be disposed on top of the driving element 110 .

[0054] In addition, an organic light-emitting element 150 electrically connected to the driving element 110 is disposed on the planarization layer 105, and a capping layer 120, a step reduction layer 190, and an inorganic layer 186 are disposed on the organic light-emitting element 150 to minimize the penetration of oxygen and moisture into the organic light-emitting element 150.

[0055] The sealing member 130 and the reinforcing substrate 140 may be disposed in this order on the inorganic layer 186, but are not limited thereto. A sealing substrate may be disposed on the inorganic layer 186 with an adhesive layer interposed therebetween.

[0056] However, the display panel 100 according to the first embodiment of the present invention is not limited to such a layered structure.

[0057] Specifically, the substrate 101 may be a glass or plastic substrate. If the substrate 101 is a plastic substrate, a polyimide-based or polycarbonate-based material may be used to provide flexibility. In particular, polyimide is often used as a plastic substrate because it can be applied to high-temperature processes and is a coatable material.

[0058] A buffer layer 102 may be disposed on the substrate 101 .

[0059] The buffer layer 102 is a layer for protecting various electrodes and wirings from impurities such as alkali ions leaked from the substrate 101 or underlying layers, and may have a multi-layer structure consisting of a first buffer layer 102a and a second buffer layer 102b, but is not limited thereto. The buffer layer 102 may be made of silicon oxide (SiOx), silicon nitride (SiNx), or a multi-layer thereof.

[0060] In addition, the buffer layer 102 can delay the diffusion of moisture and / or oxygen that has penetrated into the substrate 101. The buffer layer 102 can include a multi-buffer and / or an active buffer. The active buffer can protect the active layer 111 made of a semiconductor of the driving element 110 and block various types of impurities that may flow in from the substrate 101. The active buffer can be made of amorphous silicon (a-Si), etc.

[0061] The driving element 110 may be composed of an active layer 111 , a gate electrode 113 , and source and drain electrodes 112 , and is electrically connected to the organic light emitting element 150 through a connecting electrode 114 to transmit a current or a signal to the organic light emitting element 150 .

[0062] The active layer 111 may be disposed on the buffer layer 102. The active layer 111 may be made of polysilicon (p-Si), in which case a predetermined region may be doped with impurities. The active layer 111 may also be made of amorphous silicon (a-Si) or various organic semiconductor materials such as pentacene. The active layer 111 may also be made of an oxide semiconductor.

[0063] A gate insulating layer 103 may be disposed on the active layer 111 .

[0064] The gate insulating layer 103 may be formed of an insulating inorganic material such as silicon oxide (SiOx) or silicon nitride (SiNx), or may be formed of an insulating organic material.

[0065] A gate electrode 113 may be disposed on the gate insulating layer 103 .

[0066] The gate electrode 113 may be formed of various conductive materials, such as nickel (Ni), chromium (Cr), magnesium (Mg), aluminum (Al), molybdenum (Mo), tungsten (W), gold (Au), or alloys thereof.

[0067] An interlayer insulating layer 104 may be disposed on the gate electrode 113 .

[0068] The interlayer insulating layer 104 may be formed of an insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx), or may be formed of an insulating organic material.

[0069] By selectively removing the gate insulating layer 103 and the interlayer insulating layer 104, contact holes can be formed that expose the source and drain regions of the active layer 111. The source and drain electrodes 112 can be formed on the interlayer insulating layer 104 in a single layer or multilayer structure using an electrode material.

[0070] If necessary, an additional passivation layer made of an inorganic insulating material may be formed to cover the source and drain electrodes 112 .

[0071] A planarization layer 105 may be disposed on top of the driving element 110 configured in this manner.

[0072] The planarization layer 105 may have a multi-layer structure consisting of at least two layers, and may include, for example, a first planarization layer 105a and a second planarization layer 105b. The first planarization layer 105a may be disposed to cover the driving element 110, and may be disposed such that a portion of the source electrode and the drain electrode 112 of the driving element 110 is exposed.

[0073] The planarization layer 105 may extend into the non-display area NA to cover the GIP portion 125 .

[0074] The planarization layer 105 may have a thickness of about 2 μm, but is not limited to this.

[0075] The planarization layer 105 may be, but is not limited to, an overcoat layer.

[0076] Meanwhile, a connecting electrode 114 for electrically connecting the driving element 110 and the organic light emitting element 150 may be disposed on the first planarization layer 105a. Although not shown in FIG. 2, various metal layers serving as wiring / electrodes such as data lines and signal wiring may be disposed on the first planarization layer 105a.

[0077] In addition, a second planarization layer 105b may be disposed on the first planarization layer 105a and the connecting electrode 114.

[0078] The reason why the planarization layer 105 in the display panel 100 according to the first embodiment of the present invention is composed of two layers is that, as the resolution of the display panel 100 increases, the number of various signal wirings increases. Since it is difficult to arrange all the wirings on one layer while ensuring the minimum spacing, an additional layer is provided. The addition of this additional layer, i.e., the second planarization layer 105b, provides more space for wiring arrangement, making it easier to design wiring / electrode arrangement. Furthermore, if a dielectric material is used for the multi-layered planarization layer 105, the planarization layer 105 can also be used to form capacitance between metal layers.

[0079] The second planarization layer 105b may be formed to expose a portion of the connecting electrode 114, and the drain electrode 112 of the driving element 110 and the anode 151 of the organic light emitting element 150 may be electrically connected through the connecting electrode 114.

[0080] The organic light emitting device 150 may be configured by sequentially arranging an anode 151, a plurality of organic layers 152, and a cathode 153. That is, the organic light emitting device 150 may be configured with the anode 151 formed on the planarization layer 105, the organic layer 152 formed on the anode 151, and the cathode 153 formed on the organic layer 152.

[0081] The electroluminescent display device may be implemented as a top emission or bottom emission device. In the top emission type, a reflective layer made of a highly reflective opaque conductive material, such as silver (Ag), aluminum (Al), gold (Au), molybdenum (Mo), tungsten (W), chromium (Cr), or an alloy thereof, may be added below the anode 151 so that light emitted from the organic layer 152 is reflected by the anode 151 and directed upward, i.e., toward the upper cathode 153. In contrast, in the bottom emission type, the anode 151 may be made solely of a transparent conductive material, such as indium tin oxide (ITO), indium zinc oxide (IZO), or indium gallium zinc oxide (IGZO). The following description will be made assuming that the display panel 100 of the present invention is a bottom emission type.

[0082] A bank 106 may be disposed on the remaining area of ​​the planarization layer 105 excluding the light-emitting area. That is, the bank 106 has a bank hole exposing the light-emitting area and the corresponding anode 151. The bank 106 may be made of an inorganic insulating material such as silicon nitride (SiNx) or silicon oxide (SiOx), or an organic insulating material such as BCB, an acrylic resin, or an imide resin.

[0083] The bank 106 may extend into the non-display area NA.

[0084] The bank 106 may extend to a part of the non-display area NA so as to be spaced a certain distance from the end of the substrate 101 .

[0085] The bank 106 may have a thickness of about 1 μm, but is not limited to this.

[0086] The bank 106 may cover the top of the GIP section 125, but is not limited to this.

[0087] An organic layer 152 may be disposed on the anode 151 exposed by the bank 106. The organic layer 152 may include an emissive layer, an electron injection layer, an electron transport layer, a hole transport layer, a hole injection layer, and the like.

[0088] The organic layer 152 may extend into the non-display area NA.

[0089] The organic layer 152 may extend to a part of the non-display area NA so as to be spaced a certain distance from the end of the bank 106 .

[0090] In the non-display area NA, the organic layer 152 may be disposed on the banks 106 .

[0091] A cathode 153 may be disposed on the organic layer 152 .

[0092] In the case of a top emission type, the cathode 153 may include a transparent conductive material. For example, the cathode 153 may be made of indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), etc. In the case of a bottom emission type, the cathode 153 may include any one of a group consisting of a metal material such as gold (Au), silver (Ag), aluminum (Al), molybdenum (Mo), magnesium (Mg), palladium (Pd), copper (Cu), etc., or an alloy thereof. Alternatively, the cathode 153 may be formed by stacking a layer made of a transparent conductive material such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), or IGZO (Indium Gallium Zinc Oxide) and a layer made of a metal material such as gold (Au), silver (Ag), aluminum (Al), molybdenum (Mo), magnesium (Mg), palladium (Pd), copper (Cu), or an alloy thereof, but is not limited thereto.

[0093] The cathode 153 may extend into the non-display area NA.

[0094] The cathode 153 may be spaced a certain distance from the end of the bank 106 and may contact a portion of the top surface of the bank 106 .

[0095] In the non-display area NA, the cathode 153 may be disposed so as to cover the side surfaces of the organic layer 152. The organic layer 152 may be disposed at a certain distance from the end of the cathode 153, but is not limited thereto.

[0096] A capping layer 120 made of a material with high refractive index and light absorption rate may be disposed on the organic light emitting device 150 to reduce diffuse reflection of external light.

[0097] The capping layer 120 may be an organic layer made of an organic material, and may be omitted as necessary.

[0098] The capping layer 120 may extend into the non-display area NA. In the non-display area NA, the capping layer 120 may be disposed on the cathode 153.

[0099] Meanwhile, the display panel 100 according to the first embodiment of the present invention is characterized in that some regions of the capping layer 120, the cathode 153, and the organic layer 152 in the non-display area NA are selectively removed to form a trench pattern 180. The trench pattern 180 may be disposed in a shadow region between the ends of the cathode 153 in the non-display area NA on the periphery of the display area AA.

[0100] Furthermore, the display panel 100 according to the first embodiment of the present invention is characterized in that the capping layer 120 adjacent to the trench pattern 180 is removed so as to be recessed further inward than the cathode 153. Here, "inward" refers to the direction toward the back of the capping layer 120 and the center of the cathode 153, and may also refer to the capping layer 120 being removed so as to recede from the end of the cathode 153.

[0101] That is, the trench pattern 180 may be formed by removing the capping layer 120, the cathode 153, and the organic layer 152 in the shadow region on the periphery of the display area AA, for example, through laser melting. In this case, the capping layer 120 may be melted faster than the cathode 153, and thus may be removed so that the capping layer 120 is recessed further inward than the cathode 153. Meanwhile, the planarization layer 105 and the bank 106 may be removed through a photolithography process, which may allow the trench pattern 180 to extend downward, but is not limited thereto.

[0102] When the laser width is 50 μm, the trench pattern 180 may be formed to have a width of about 70 μm, but is not limited to this, taking into consideration the width (about 20 μm) of the region affected by the laser heat.

[0103] A portion of the cathode 153 adjacent to the trench pattern 180 may be spaced apart from the organic layer 152. The shapes of the capping layer 120, the cathode 153, and the organic layer 152 after laser irradiation will be described in more detail below with reference to FIGS. 4a to 4c and 5a to 5c.

[0104] In the first embodiment of the present invention, the cathode 153 in the display area AA and the cathode 153 in the non-display area NA can be separated from each other by forming the trench pattern 180 in the non-display area NA. This effectively has the effect of recessing the end of the cathode 153 into the display area AA, thereby increasing the reliable bezel area L and thereby reducing the bezel width.

[0105] That is, as described above, an electroluminescent display device requires a minimum bezel distance, that is, a reliable bezel area L, in order to ensure reliability such as moisture prevention.

[0106] In this case, a reliable bezel area L may be defined as the distance from the edge of the reinforcing substrate 140 to the edge of the cathode 153. The area of ​​the non-display area NA excluding the reliable bezel area L may be referred to as a shadow area, which is located on the outer periphery of the display area AA. The shadow area may be defined by a gap between the mask and the substrate 101 during deposition of the cathode 153 and the organic layer 152.

[0107] The first embodiment of the present invention is characterized in that the trench pattern 180 is arranged outside the shadow area, that is, within the reliable bezel area L.

[0108] 3 illustrates an example in which two trench patterns 180 are provided, but is not limited thereto. That is, one or more trench patterns 180 may be provided, and the number of trench patterns 180 is not limited to that illustrated in FIG.

[0109] Although not shown, a protective layer for protecting the GIP portion 125 from laser melting may be further disposed at the bottom of the interior of the trench pattern 180, but is not limited thereto.

[0110] In this case, when a laser having a wavelength band of about 266 nm in the ultraviolet region is used, the protective layer may be formed of a transparent conductive material constituting the anode 151 to fully absorb the laser. The transparent conductive material may include ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), or IGZO (Indium Gallium Zinc Oxide).

[0111] A step mitigating layer 190 , an inorganic layer 186 , a sealing member 130 , and a reinforcing substrate 140 may be disposed on the capping layer 120 , including inside the trench pattern 180 .

[0112] First, the step mitigation layer 190 may be disposed on the capping layer 120 and may be disposed to fill the inside of the trench pattern 180. That is, the step mitigation layer 190 may be disposed to fill the inside of the trench pattern 180, thereby mitigating the step caused by the trench pattern 180 and planarizing the upper surface of the trench pattern 180.

[0113] In addition, the step mitigating layer 190, together with the capping layer 120, the inorganic layer 186, and the reinforcing substrate 140, can protect the organic light emitting device 150 of the pixel unit 115 from external moisture, oxygen, impact, and the like.

[0114] The step reduction layer 190 may be made of an organic material.

[0115] For example, the step reduction layer 190 may include an organic resin and a getter 195 dispersed in the resin.

[0116] The resin of the step mitigating layer 190 may be made of an organic material. For example, the step mitigating layer 190 may include an epoxy resin, an acrylic resin, and a silicon oxycarbon (SiOC) resin.

[0117] The step mitigation layer 190 may include a getter 195. The getter 195 may be dispersed in the resin described above.

[0118] The getter 195 may include at least one of barium oxide (BaO), calcium oxide (CaO), magnesium oxide (MgO), magnesium sulfate (MgSO), sodium oxide (NaO), sodium sulfate (NaSO), lithium sulfate (LiSO), calcium sulfate (CaSO), potassium oxide (KO), lithium oxide (LiO), gallium sulfate (GaS), calcium chloride (CaCl), magnesium chloride (MgCl), calcium bromide (CaBr), cerium bromide (CsBr), vanadium bromide (VBr), and calcium nitrate (Ca(No)).

[0119] The getter 195 may be made of particles having a size of about 50 to 100 nm, and may be made of a transparent material, but is not limited thereto.

[0120] The step mitigating layer 190 may be implemented as a film. That is, the step mitigating layer 190 may not be formed by applying and hardening a liquid material, but may be implemented in the form of a film and disposed on the capping layer 120. Therefore, the step mitigating layer 190 may be made of an organic film.

[0121] In the first embodiment of the present invention, the step reduction layer 190 may be disposed to contact a portion of the top surface of the capping layer 120 disposed outside the outermost trench pattern 180, including the capping layer 120, the exposed cathode 153, and the inside of the trench pattern 180, but the present invention is not limited thereto. Here, the outermost trench pattern 180 may refer to the trench pattern 180 disposed outermost when a plurality of trench patterns 180 are disposed.

[0122] An inorganic layer 186 made of an inorganic insulating material may be disposed on the step reduction layer 190. The inorganic layer 186 can retard moisture permeation from the upper portion and can prevent defects due to cuts or foreign matter.

[0123] In this case, the inorganic layer 186 may be disposed to contact the upper surface of the step mitigating layer 190 and a portion of another upper surface of the capping layer 120. That is, the inorganic layer 186 may cover the upper surface and side surfaces of the step mitigating layer 190 to seal the step mitigating layer 190. In addition, the inorganic layer 186 may cover a portion of another upper surface and side surfaces of the capping layer 120 disposed outside the outermost trench pattern 180 that is not completely covered by the step mitigating layer 190, as well as the side surfaces of the cathode 153.

[0124] The inorganic layer 186 may be made of, but is not limited to, silicon oxide (SiOx), silicon nitride (SiNx), or multiple layers thereof to retard moisture permeation.

[0125] A multilayer sealing structure composed of a sealing member 130 and a reinforcing substrate 140 may be disposed on top of the inorganic layer 186, but is not limited thereto, and a sealing substrate may be disposed on the inorganic layer 186 with an adhesive layer interposed therebetween.

[0126] Small-sized display panels used in mobile and portable devices have a small display panel area, so heat generated by the elements can be quickly dissipated and there are fewer adhesion problems. However, large-sized display panels used in monitors, tablets, and televisions have a large display panel area, so a sealing structure is required for optimal heat dissipation and adhesion.

[0127] In addition, to compensate for the insufficient rigidity, the EL display may further include a separate inner plate on the encapsulation substrate. In this case, a space for disposing the separate inner plate must be secured, and the weight of the inner plate limits the slimming and weight reduction of the EL display. In addition, an air gap occurs between the encapsulation substrate and the inner plate by the thickness of an adhesive tape disposed to bond the encapsulation substrate and the inner plate, creating a vertical separation space, which reduces heat dissipation performance.

[0128] Therefore, the first embodiment of the present invention is characterized by applying a multi-layered sealing structure including a sealing member 130 that can fix a relatively thick reinforcing substrate 140 without requiring a separate inner plate and can prevent process defects.

[0129] The sealing member 130 of the present invention may include a first adhesive layer 131 facing the substrate 101, a second adhesive layer 133 facing the reinforcing substrate 140, and a barrier layer 132 disposed between the first adhesive layer 131 and the second adhesive layer 133.

[0130] The first adhesive layer 131 and the second adhesive layer 133 may each be made of an adhesive polymer material. For example, the first adhesive layer 131 may be made of any one of an olefin-based, epoxy-based, and acrylate-based polymer material. The second adhesive layer 133 may be made of any one of an olefin-based, epoxy-based, acrylate-based, amine-based, phenol-based, and acid anhydride-based polymer material that does not contain a carboxyl group. In particular, the second adhesive layer 133 is preferably made of a polymer material that does not contain a carboxyl group to ensure film uniformity of the barrier layer 132 and to prevent corrosion.

[0131] For heat dissipation of the substrate 101, at least the first adhesive layer 131 of the first and second adhesive layers 131, 133 may be made of a mixture containing adhesive polymer material and metal material particles. As an example, the metal material particles may be nickel (Ni) powder. The first adhesive layer 131, which is in direct contact with the substrate 101, is made of a mixture containing adhesive polymer material and metal material particles, and therefore may have higher thermal conductivity than an adhesive polymer material.

[0132] Similarly, the second adhesive layer 133 is also made of a mixture containing particles of an adhesive polymer material and a metal material, and can have higher thermal conductivity than an adhesive polymer material.

[0133] In this way, the speed at which the driving heat generated in the substrate 101 is released through the sealing member 130 can be increased, and the heat dissipation effect on the substrate 101 can be improved.

[0134] In addition, the first adhesive layer 131 may be made of a mixture further containing a hygroscopic inorganic filler to prevent moisture from passing through the pixel unit 115. In this case, the hygroscopic inorganic filler may be at least one of barium oxide (BaO), calcium oxide (CaO), and magnesium oxide (MgO).

[0135] Unlike the first adhesive layer 131, the second adhesive layer 133 does not directly contact the pixel unit 115, and therefore does not need to include an inorganic filler to prevent moisture from passing through the pixel unit 115. Therefore, the second adhesive layer 133 does not include a hygroscopic inorganic filler, and can include only particles of an adhesive polymer material and a metal material. In this way, the amount of relatively expensive hygroscopic inorganic filler added to the sealing member 130 can be reduced, and the preparation cost of the sealing member 130 can be reduced.

[0136] Furthermore, since the second adhesive layer 133 does not contain a hygroscopic inorganic filler, the mixing ratio of the polymer material contained in the second adhesive layer 133 may be increased compared to the first adhesive layer 131, and therefore the adhesiveness of the second adhesive layer 133 may be improved compared to the adhesiveness of the first adhesive layer 131. As a result, the reinforcing substrate 140 may be more firmly fixed on the second adhesive layer 133, and the reliability of the adhesion between the substrate 101 and the reinforcing substrate 140 may be further improved.

[0137] In addition, by forming the first adhesive layer 131 and the second adhesive layer 133 in a multi-layer structure, there is an advantage that the warpage phenomenon in which the display panel warps can be reduced, and reliability can also be improved.

[0138] The thickness of each of the first and second adhesive layers 131 and 133 may be limited to a critical thickness or less to prevent process defects, and the sum of the thicknesses of the first and second adhesive layers 131 and 133 may be limited to a critical thickness or more to ensure reliability in fixing the reinforcing substrate 140.

[0139] For example, the thickness of each of the first and second adhesive layers 131 and 133 may be within the range of 10 um to 100 um.

[0140] The barrier layer 132 may be made of either a metal material or an inorganic insulating material. That is, the barrier layer 132 may be made of a metal material such as Al, Cu, Sn, Ag, Fe, Zn, etc. In another example, the barrier layer 132 may be made of a thin film of an inorganic insulating material such as SiOx or SiONx.

[0141] The barrier layer 132 can be introduced to implement a laminated structure that reinforces the adhesion between the first and second adhesive layers 131 and 133 and reduces warpage. Specifically, the first and second adhesive layers 131 and 133 are each made of a polymer material having adhesive properties. Therefore, the barrier layer 132, which is made of a relatively hard material, is disposed between the first adhesive layer 131 and the second adhesive layer 133, and the first adhesive layer 131 and the second adhesive layer 133 are attached to one side and the other side of the barrier layer 132, respectively, thereby improving adhesion.

[0142] At this time, the thickness of the barrier layer 132 may be limited to a value smaller than the thicknesses of the first and second adhesive layers 131 and 133 in order to minimize an increase in the thickness of the sealing member 130 due to the barrier layer 132. For example, the thickness of the barrier layer 132 may be within a range greater than 10 μm and smaller than the thicknesses of the first and second adhesive layers 131 and 133.

[0143] As described above, the sealing member 130 of the first embodiment of the present invention includes the first and second adhesive layers 131 and 133 separated by the barrier layer 132, and therefore can be implemented with a thickness approximately twice as thick as a single layer of adhesive material without process defects. As a result, the reinforcing substrate 140 fixed by the sealing member 130 can be provided with a large thickness, which has the advantage of easily achieving increased rigidity and improved heat dissipation. That is, when the thickness of the sealing member 130 is within the range of 30 μm to 300 μm, the thickness of the reinforcing substrate 140 can be implemented with a thickness within the range of 0.1 mm to 1.5 mm.

[0144] For example, the reinforcing substrate 140 may be made of any one of glass, metal, and plastic polymer, for example, a metal material containing Al, Cu, Sn, Ag, Fe, or Zn.

[0145] The sealing member 130 and the reinforcing substrate 140 may extend into the non-display area NA to cover a portion of the planarization layer 105 and the banks 106 .

[0146] Meanwhile, as mentioned above, laser irradiation may cause a lifting phenomenon in which a portion of the cathode 153 disposed adjacent to the trench pattern 180 is separated from the organic layer 152, but this can be improved by reducing the laser spot size or using the step reduction layer 190 mentioned above.

[0147] 4a to 4c are focused ion beam (FIB) images of region A in FIG.

[0148] 5a to 5c are FIB images of region A in FIG. 3 viewed from above.

[0149] 4a-4c and 5a-5c show exemplary shapes of the organic layer, cathode and capping layer disposed adjacent to the trench pattern.

[0150] Figures 4a and 5a show trenches formed using a laser with a spot size of approximately 30 μm, Figures 4b and 5b show trenches formed using a laser with a spot size of approximately 8 μm, and Figures 4c and 5c show trenches formed using a laser with a spot size of approximately 3 μm.

[0151] 4a to 4c and 5a to 5c, a portion of the cathode adjacent to the trench pattern may be disposed so as to be spaced apart from the organic layer. As described above, the trench pattern may be formed by removing the capping layer, cathode, and organic layer in the shadow region outside the display area through laser melting. At this time, due to differences in laser absorptivity between the capping layer, the cathode, and the organic layer, the portion of the cathode adjacent to the trench pattern may be separated from the organic layer, resulting in a curled or lifted-up phenomenon. Furthermore, the capping layer adjacent to the trench pattern may be removed so as to be recessed further inward than the cathode. That is, the capping layer may be melted by the laser more quickly than the cathode, so that the capping layer may be removed so as to be recessed further inward than the cathode.

[0152] 4A and 5A, when a trench pattern is formed using a laser with a spot size of about 30 μm, a portion of the cathode in the area adjacent to the trench pattern may be raised upward. That is, the end of the cathode may be raised upward and spaced apart from the organic layer. In this case, the capping layer adjacent to the trench pattern may be removed so that it is recessed further inward relative to the cathode.

[0153] At this time, the laser processing speed may be approximately 600 mm per second.

[0154] 4B and 5B, when a trench pattern is formed using a laser with a spot size of about 8 μm, the end of the cathode in the region adjacent to the trench pattern may be folded upward and toward the organic layer, forming a rolled shape. In this case, the capping layer adjacent to the trench pattern may be removed so as to be recessed further inward than the cathode.

[0155] At this time, the laser processing speed may be about 100 mm per second.

[0156] 4c and 5c, when a trench pattern is formed using a laser with a spot size of about 3 μm, the lifting and curling of the cathode edge in the area adjacent to the trench pattern is alleviated. In this case, too, the capping layer adjacent to the trench pattern can be removed so that it is recessed further inward relative to the cathode.

[0157] At this time, the laser processing speed may be about 10 mm per second.

[0158] In this way, when the laser spot size is reduced and the processing speed is decreased, the cathode lift-up can be improved and the height of the cathode end can be maintained uniform.

[0159] However, the shape of the portion of the cathode adjacent to the trench pattern is not limited to those shown in FIGS. 4a to 4c, and may have various shapes.

[0160] 3, the step reduction layer 190 may be disposed on the capping layer 120 and fill the trench pattern 180. That is, the step reduction layer 190 may cover the side surfaces of the cathode 153 and the organic layer 152 where a step is formed due to the lifting of the cathode 153 in the region adjacent to the trench pattern 180. The step reduction layer 190 may also fill the space between the cathode 153 and the organic layer 152 to cover the rolled or lifted shape of the cathode 153. That is, as shown in FIGS. 4a to 4c, the step reduction layer 190 may fill the space formed when a portion of the cathode 153 adjacent to the trench pattern 180 is separated from the organic layer 152, thereby planarizing the tops of the cathode 153 and the capping layer 120.

[0161] In line with the demand for slimmer EL displays, there is also an increasing demand for a smaller non-display area of ​​the EL display, excluding the display area where an image is displayed. However, there is a limit to how much the bezel can be reduced because a shadow area occurs due to a gap between the mask and the substrate during deposition of the cathode and organic layers.

[0162] Furthermore, currently, a minimum bezel distance is required to ensure reliability, such as moisture prevention, in electroluminescent displays, and this can be called a reliable bezel. For example, a reliable bezel can be defined as the distance from the edge of the upper substrate (encapsulation substrate) to the edge of the cathode. Therefore, there is a limit to how much the bezel can be reduced in order to ensure a reliable bezel.

[0163] Therefore, in the electroluminescent display device according to the first embodiment of the present invention, in order to ensure reliability such as moisture permeation prevention, a trench pattern 180 may be formed in the electroluminescent display device by removing a portion of the capping layer 120, the cathode 153, and the organic layer 152. Therefore, by forming the trench pattern 180 in an unnecessary shadow region generated by using a deposition mask, the speed of moisture permeation from the side can be slowed down, improving reliability and simultaneously reducing the bezel width.

[0164] Meanwhile, during the formation of the trench pattern 180, a laser ablation method may be used to remove the capping layer 120, the cathode 153, and the organic layer 152. However, due to differences in laser absorptivity between the capping layer 120, the cathode 153, and the organic layer 152, a portion of the cathode 153 adjacent to the trench pattern 180 may be separated from the organic layer 152, resulting in a curled or lifted-up phenomenon. For example, an end of the cathode 153 may protrude or lift upward in an area adjacent to the trench pattern 180 where the laser is irradiated. In particular, the larger the area irradiated with the laser, the more severe the curled or lifted shape of the cathode 153 and the more severe the lift-up phenomenon between the cathode 153 and the organic layer 152. Furthermore, the capping layer 120 adjacent to the trench pattern 180 may be removed so as to be recessed further inward than the cathode 153. Therefore, a step may occur due to the cathode 153 in an area adjacent to the trench pattern 180, and residue may be generated during the laser irradiation process, forming foreign matter, which may cause the top surface of the cathode 153 to become uneven and reduce the quality of the film disposed on the cathode 153. Specifically, if an inorganic layer that retards moisture permeation is disposed on the cathode 153, the inorganic layer may be damaged by the generation of seams and foreign matter, resulting in problems such as moisture permeation through the damaged interface.

[0165] Therefore, in the first embodiment of the present invention, a step reduction layer 190 capable of ensuring step coverage is disposed on the upper part of the trench pattern 180. During the formation of the trench pattern 180, the cathode 153 may be spaced apart from the underlying organic layer 152. The step reduction layer 190 can fill the trench pattern 180 and fill the separation space between the cathode 153 and the organic layer 152 generated by laser melting, thereby reducing abrupt step changes due to the protruding shape of the cathode 153. In addition, the upper part of the trench pattern 180 can be planarized to reduce steps due to the end shapes of the capping layer 120 and the cathode 153, thereby preventing the occurrence of seams.

[0166] Therefore, the quality of the film disposed on top of the cathode 153 can be prevented from deteriorating, and when an inorganic layer 186 is disposed on top of the cathode 153, the flatness of the inorganic layer 186 can be improved, thereby improving the reliability of the moisture-proofing performance of the electroluminescent display device.

[0167] Furthermore, the first embodiment of the present invention can delay moisture permeation by including a getter 195 in the step mitigating layer 190. The getter 195 can absorb moisture and oxygen that has entered the internal space of the step mitigating layer 190 and prevent moisture diffusion. Therefore, the moisture permeation path through the film disposed under the step mitigating layer 190 can be controlled.

[0168] FIG. 6 is a graph showing transmittance as a function of wavelength for a capping layer, an organic layer, a cathode, and a triplex film according to some aspects of the present invention.

[0169] FIG. 7 is a table showing transmittance by laser wavelength for the capping layer, organic layer, cathode, and triplex according to some aspects of the present invention.

[0170] 6, the transmittance of the capping layer and organic layer increases with increasing wavelength, whereas the transmittance of the cathode and triple layer is nearly 0% across all wavelength bands.

[0171] Referring to FIG. 7, it can be seen that for a laser wavelength of 1064 nm, the transmittance for the capping layer, organic layer, cathode and triple layer is 90.06%, 86.16%, 0% and 0%, respectively.

[0172] It is also found that for a laser wavelength of 532 nm, the transmittances for the capping layer, organic layer, cathode and triplex are 84.25%, 90.12%, 0% and 0.03%, respectively.

[0173] It is also found that for a laser wavelength of 355 nm, the transmittance for the capping layer, organic layer, cathode and triplex is 1.2%, 32.8%, 0% and 0%, respectively.

[0174] Therefore, in order to simultaneously remove the triple layer, the capping layer and the organic layer must have high absorption rates for the laser irradiation wavelength, so it is preferable to use a 355 nm UV laser.

[0175] Meanwhile, the inorganic layer of the present invention can be extended to the non-display area, which will be described in detail with reference to FIG.

[0176] FIG. 8 is a cross-sectional view showing a display panel according to a second embodiment of the present invention.

[0177] The display panel 200 according to the second embodiment of the present invention shown in FIG. 8 differs from the display panel 100 according to the first embodiment of the present invention shown in FIG. 3 described above only in the configuration of the inorganic layer 286. For the sake of convenience, redundant explanations of the same configuration will be omitted.

[0178] Referring to FIG. 8, a display panel 200 according to the second embodiment of the present invention may have a pixel unit 115 and a GIP unit 125 disposed on a substrate 101.

[0179] A planarization layer 105 may then be disposed on top of the GIP portion 125 .

[0180] In addition, the organic light emitting element may be disposed on the planarization layer 105, and the capping layer 120, the step mitigation layer 190, and the inorganic layer 286 may be disposed on the organic light emitting element.

[0181] In addition, the sealing member 130 and the reinforcing substrate 140 may be disposed in this order on the inorganic layer 286, but are not limited thereto, and a sealing substrate may be disposed on the inorganic layer 286 with an adhesive layer interposed therebetween.

[0182] However, the display panel 200 according to the second embodiment of the present invention is not limited to such a layered structure.

[0183] The planarization layer 105 may extend into the non-display area NA to cover the GIP portion 125 .

[0184] The organic light emitting device may be composed of an anode formed on the planarization layer 105 , an organic layer 152 formed on the anode, and a cathode 153 formed on the organic layer 152 .

[0185] Banks 106 may be disposed on the planarization layer 105 in the remaining area excluding the light-emitting area.

[0186] The bank 106 may extend into the non-display area NA.

[0187] That is, the bank 106 may extend to a part of the non-display area NA so as to be spaced a certain distance from the end of the substrate 101 .

[0188] The bank 106 may cover the top of the GIP section 125, but is not limited to this.

[0189] An organic layer 152 may be disposed on the anode exposed by the bank 106 .

[0190] The organic layer 152 may extend into the non-display area NA.

[0191] The organic layer 152 may extend to a part of the non-display area NA so as to be spaced a certain distance from the end of the bank 106 .

[0192] In the non-display area NA, the organic layer 152 may be disposed on the banks 106 .

[0193] A cathode 153 may be disposed on the organic layer 152 .

[0194] The cathode 153 may extend into the non-display area NA.

[0195] The cathode 153 may be spaced a certain distance from the end of the bank 106 and may contact a portion of the top surface of the bank 106 .

[0196] In the non-display area NA, the cathode 153 may be disposed so as to cover the side surfaces of the organic layer 152. The organic layer 152 may be disposed at a certain distance from the end of the cathode 153, but is not limited thereto.

[0197] A capping layer 120 may be disposed on the cathode 153 .

[0198] The capping layer 120 may extend into the non-display area NA. In the non-display area NA, the capping layer 120 may be disposed on the cathode 153.

[0199] As described above, the display panel 200 according to the second embodiment of the present invention is characterized in that the capping layer 120, the cathode 153, and some regions of the organic layer 152 in the non-display area NA are removed to form the trench pattern 180. The trench pattern 180 may be disposed in a shadow area between the ends of the cathode 153 in the non-display area NA on the periphery of the display area AA.

[0200] Also, the display panel 200 according to the second embodiment of the present invention is characterized in that the capping layer 120 adjacent to the trench pattern 180 is removed so as to be recessed further inward than the cathode 153 .

[0201] In addition, a portion of the cathode 153 adjacent to the trench pattern 180 may be spaced apart from the organic layer 152 .

[0202] In the second embodiment of the present invention, similarly to the first embodiment, a trench pattern 180 is formed in the non-display area NA, so that the cathode 153 in the display area AA and the cathode 153 in the non-display area NA can be separated from each other.

[0203] A step mitigating layer 190 may be disposed on the capping layer 120, including the inside of the trench pattern 180. The step mitigating layer 190 may be disposed so as to fill the inside of the trench pattern 180.

[0204] The step reduction layer 190 may be made of an organic material and may include a resin and a getter 195 dispersed in the resin.

[0205] The step mitigating layer 190 may be embodied in the form of a film.

[0206] An inorganic layer 286 made of an inorganic insulating material may be disposed on the step reduction layer 190 .

[0207] The inorganic layer 286 according to the second embodiment of the present invention may be disposed to contact the top surface of the step mitigating layer 190 and a portion of another top surface of the capping layer 120. That is, the inorganic layer 286 may cover the top and side surfaces of the step mitigating layer 190 to seal the step mitigating layer 190. In addition, the inorganic layer 286 according to the second embodiment of the present invention may cover not only a portion of another top surface and side surfaces of the capping layer 120 disposed outside the outermost trench pattern 180 that is not completely covered by the step mitigating layer 190 and extends to the end of the sealing member 130 and the reinforcing substrate 140 and extends to the side of the cathode 153, but also a portion of the top surface and side surfaces of the bank 106 extending into the non-display area NA and a portion of the top surface of the planarization layer 105.

[0208] That is, the inorganic layer 286 may contact a portion of the upper surface and side surfaces of the bank 106 and a portion of the upper surface of the planarization layer 105. The inorganic layer 286 may also extend to the ends of the sealing member 130 and the reinforcing substrate 140 so that the side surfaces are exposed.

[0209] In this way, the inorganic layer 286 is formed to extend to cover part of the upper surface and side of the bank 106 extending into the non-display area NA and part of the upper surface of the planarization layer 105, thereby effectively blocking oxygen transmission and moisture penetration on the side of the display panel 200.

[0210] Meanwhile, the step mitigating layer of the present invention can be extended to the non-display area so as to completely cover the capping layer and the cathode, which will be described in detail with reference to FIG.

[0211] FIG. 9 is a cross-sectional view showing a display panel according to a third embodiment of the present invention.

[0212] The display panel 300 according to the third embodiment of the present invention shown in Figure 9 differs from the display panel 100 according to the first embodiment of the present invention shown in Figure 3 described above only in the configuration of the step reduction layer 390 and the inorganic layer 386, and for the sake of convenience, duplicated descriptions of the same configurations will be omitted.

[0213] Referring to FIG. 9, the display panel 300 of the third embodiment of the present invention is characterized in that, similar to the first and second embodiments of the present invention, some regions of the capping layer 120, cathode 153 and organic layer 152 in the non-display area NA are selectively removed to form a trench pattern 180.

[0214] Furthermore, the display panel 300 according to the third embodiment of the present invention is characterized in that the capping layer 120 adjacent to the trench pattern 180 is removed so as to be recessed further inward than the cathode 153 .

[0215] In addition, a portion of the cathode 153 adjacent to the trench pattern 180 may be spaced apart from the organic layer 152 .

[0216] In the third embodiment of the present invention, a step mitigating layer 390 may be disposed on the capping layer 120, including the inside of the trench pattern 180, as in the first and second embodiments. The step mitigating layer 390 may be disposed to fill the inside of the trench pattern 180. In particular, the step mitigating layer 390 according to the third embodiment of the present invention is characterized in that it is extended into the non-display area NA to completely cover the capping layer 120 and the cathode 153. The step mitigating layer 390 may completely cover the capping layer 120 and the cathode 153 disposed outside the outermost trench pattern 180, and may contact a portion of the top surface of the bank 106 extending outside the capping layer 120 and the cathode 153.

[0217] In this way, the step reduction layer 390 is formed to extend to completely cover the sides of the capping layer 120 and cathode 153 arranged outside the outermost trench pattern 180, thereby effectively blocking oxygen permeation and moisture penetration at the sides of the display panel 300.

[0218] The step reduction layer 390 may be made of an organic material and may include a resin and a getter 395 dispersed in the resin.

[0219] The step mitigation layer 390 may be embodied in a film form, and the upper surface thereof may be planarized.

[0220] An inorganic layer 386 made of an inorganic insulating material may be disposed on the step reduction layer 390 .

[0221] The inorganic layer 386 according to the third embodiment of the present invention may be disposed so as to contact the upper and side surfaces of the step mitigation layer 390 and a portion of the upper surface of the bank 106. That is, the inorganic layer 386 may cover the upper and side surfaces of the step mitigation layer 390 so as to seal the step mitigation layer 390. The inorganic layer 386 may also contact a portion of the upper surface of the bank 106.

[0222] Meanwhile, the step reduction layer of the present invention can be extended to the non-display area so as to completely cover the bank, which will be described in detail with reference to FIG.

[0223] FIG. 10 is a cross-sectional view showing a display panel according to a fourth embodiment of the present invention.

[0224] The display panel 400 according to the fourth embodiment of the present invention shown in Figure 10 differs from the display panel 100 according to the first embodiment of the present invention shown in Figure 3 described above only in the configuration of the step reduction layer 490 and the inorganic layer 486, and for the sake of convenience, duplicated descriptions of the same configurations will be omitted.

[0225] Referring to FIG. 10, the display panel 400 of the fourth embodiment of the present invention is characterized in that, similar to the first to third embodiments of the present invention, some regions of the capping layer 120, cathode 153 and organic layer 152 in the non-display area NA are selectively removed to form a trench pattern 180.

[0226] Furthermore, the display panel 400 according to the fourth embodiment of the present invention is characterized in that the capping layer 120 adjacent to the trench pattern 180 is removed so as to be recessed further inward than the cathode 153 .

[0227] In addition, a portion of the cathode 153 adjacent to the trench pattern 180 may be spaced apart from the organic layer 152 .

[0228] In the fourth embodiment of the present invention, similar to the first to third embodiments described above, a step reduction layer 490 may be disposed on the capping layer 120, including the inside of the trench pattern 180. The step reduction layer 490 may be disposed to fill the inside of the trench pattern 180. In particular, the step reduction layer 490 according to the fourth embodiment of the present invention is characterized in that it is extended into the non-display area NA to completely cover the capping layer 120, the cathode 153, and the bank 106. The step reduction layer 490 completely covers the capping layer 120, the cathode 153, and the bank 106 disposed outside the outermost trench pattern 180, and may contact a portion of the top surface of the planarization layer 105 extending outside the bank 106.

[0229] In this way, the step reduction layer 490 is extended and formed to completely cover the capping layer 120 arranged outside the outermost trench pattern 180, the cathode 153, and the side of the bank 106, thereby more effectively blocking oxygen permeation and moisture penetration at the side of the display panel 400.

[0230] The step reduction layer 490 may be made of an organic material and may include a resin and a getter 495 dispersed in the resin.

[0231] The step reduction layer 490 may be embodied in a film form, and the upper surface thereof may be planarized.

[0232] An inorganic layer 486 made of an inorganic insulating material may be disposed on the step reduction layer 490 .

[0233] The inorganic layer 486 according to the fourth embodiment of the present invention may be disposed to contact the upper and side surfaces of the step reduction layer 490 and a portion of the upper surface of the planarization layer 105. That is, the inorganic layer 486 according to the fourth embodiment of the present invention may cover the upper and side surfaces of the step reduction layer 490 so as to seal the step reduction layer 490. The inorganic layer 486 may also contact a portion of the upper surface of the planarization layer 105.

[0234] Meanwhile, the inorganic layer of the present invention can be extended to the non-display area, which will be described in detail with reference to FIG.

[0235] FIG. 11 is a cross-sectional view showing a display panel according to a fifth embodiment of the present invention.

[0236] The display panel 500 according to the fifth embodiment of the present invention shown in FIG. 11 differs from the display panel 400 according to the fourth embodiment of FIG. 10 described above only in the configuration of the inorganic layer 586, and for the sake of convenience, redundant descriptions of the same configuration will be omitted.

[0237] Referring to FIG. 11, the display panel 500 of the fifth embodiment of the present invention is characterized in that, similar to the fifth embodiment of the present invention described above, some areas of the capping layer 120, cathode 153 and organic layer 152 in the non-display area NA are removed to form a trench pattern 180.

[0238] Furthermore, the display panel 500 according to the fifth embodiment of the present invention is characterized in that the capping layer 120 adjacent to the trench pattern 180 is removed so as to be recessed further inward than the cathode 153 .

[0239] In addition, a portion of the cathode 153 adjacent to the trench pattern 180 may be spaced apart from the organic layer 152 .

[0240] In the fifth embodiment of the present invention, a step mitigating layer 490 may be disposed on the capping layer 120 including the inside of the trench pattern 180, similar to the fourth embodiment described above.

[0241] An inorganic layer 586 made of an inorganic insulating material may be disposed on the step reduction layer 490 .

[0242] The inorganic layer 586 according to the fifth embodiment of the present invention may be disposed to contact the upper and side surfaces of the step reduction layer 490 and a portion of the upper surface of the planarization layer 105. That is, the inorganic layer 586 according to the fifth embodiment of the present invention may cover the upper and side surfaces of the step reduction layer 490 so as to seal the step reduction layer 490. Furthermore, the inorganic layer 586 according to the fifth embodiment of the present invention may extend to the ends of the sealing member 130 and the reinforcing substrate 140 and cover a portion of the upper surface of the planarization layer 105 that extends into the non-display area NA.

[0243] That is, the inorganic layer 586 may extend to the ends of the sealing member 130 and the reinforcing substrate 140 so that the sides are exposed.

[0244] In this way, the inorganic layer 586 is extended and formed to cover a portion of the upper surface of the planarization layer 105 extending into the non-display area NA, thereby effectively blocking oxygen permeation and moisture penetration on the side surfaces of the display panel 500.

[0245] An electroluminescent display device according to an embodiment of the present invention can be described as follows.

[0246] An electroluminescent display device according to one embodiment of the present invention includes a substrate including a display area and a non-display area outside the display area, a planarization layer disposed on the substrate and extending from the display area to the non-display area, a bank disposed on the planarization layer extending to the non-display area, an organic layer disposed on the bank, a cathode disposed on the organic layer, a capping layer disposed on the cathode, a trench pattern disposed in the non-display area from which the capping layer, the cathode, and the organic layer have been removed, and a step reduction layer that fills the trench pattern and planarizes an upper portion of the trench pattern, and the capping layer disposed adjacent to the trench pattern may be recessed inward relative to the cathode.

[0247] According to another aspect of the present invention, the step mitigating layer may be embodied as a film.

[0248] According to another aspect of the present invention, the step reduction layer may include a getter.

[0249] According to another aspect of the present invention, the cathode disposed outside the trench pattern may be disposed to cover a side surface of the organic layer.

[0250] According to another aspect of the present invention, the electroluminescent display device may further include an inorganic layer disposed on the step reducing layer.

[0251] According to another aspect of the present invention, the step reduction layer may be disposed to contact a portion of the upper surface of the capping layer disposed outside the trench pattern.

[0252] According to another aspect of the present invention, the inorganic layer may be disposed to contact the upper surface and side surfaces of the step reduction layer, a portion of another upper surface of the capping layer, and a portion of an upper surface of the bank.

[0253] According to another aspect of the present invention, the inorganic layer may be disposed so as to contact a portion of the upper surface and side surfaces of the bank and a portion of the upper surface of the planarizing layer.

[0254] According to another feature of the present invention, the step reduction layer may be arranged to cover the capping layer and the cathode arranged outside the trench pattern, while contacting a portion of the upper surface of the bank extending outside the capping layer and the cathode.

[0255] According to another aspect of the present invention, the inorganic layer may be disposed so as to be in contact with the upper surface and side surfaces of the step reduction layer and a part of another upper surface of the bank.

[0256] According to another feature of the present invention, the step reduction layer may be arranged to cover the capping layer, the cathode, and the bank arranged outside the trench pattern, while contacting a portion of the upper surface of the planarization layer extending outside the bank.

[0257] According to another aspect of the present invention, the inorganic layer may be disposed so as to be in contact with an upper surface and a side surface of the step reduction layer and a part of another upper surface of the planarization layer.

[0258] According to another aspect of the present invention, the inorganic layer may be extended and disposed in the non-display area so that a side surface thereof is exposed.

[0259] According to another aspect of the present invention, the end of the cathode disposed adjacent to the trench pattern may have a raised or rolled shape toward the top.

[0260] According to another aspect of the present invention, an end of the cathode may be disposed so as to be spaced apart from the organic layer.

[0261] According to another aspect of the present invention, the step mitigating layer may fill a space between the cathode and the organic layer.

[0262] According to another aspect of the present invention, the electroluminescent display device may further include a sealing member and a reinforcing substrate having a multi-layer structure disposed on the inorganic layer.

[0263] According to another feature of the present invention, the sealing member may include a first adhesive layer disposed on the step mitigating layer and facing the substrate, a second adhesive layer facing the reinforcing substrate, and a barrier layer disposed between the first adhesive layer and the second adhesive layer.

[0264] According to another aspect of the present invention, the inorganic layer may extend to edges of the sealing member and the reinforcing substrate.

[0265] According to another aspect of the present invention, the inorganic layer may have exposed sides.

[0266] Although the present invention has been described in detail above with reference to the accompanying drawings, the present invention is not necessarily limited to these embodiments and may be variously modified within the scope of the technical concept of the present invention. Therefore, the disclosed embodiments are for illustrative purposes only and do not limit the technical concept of the present invention. Therefore, the above-described embodiments should be understood to be illustrative in all respects and not restrictive. The scope of the present invention should be interpreted by the scope of the following claims, and all technical concepts within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.

Claims

1. a substrate including a display area and a non-display area outside the display area; a planarization layer disposed on the substrate and extending from the display area to the non-display area; a bank extending to the non-display area and disposed on the planarization layer; an organic layer disposed on the bank; a cathode disposed over the organic layer; a capping layer disposed on the cathode; a trench pattern formed in the non-display area, the trench pattern being formed by removing the capping layer, the cathode, and the organic layer; a step reduction layer that fills the trench pattern and flattens the upper surface of the trench pattern; A silicon oxide (SiO ｘ ), silicon nitride (SiN ｘ ) or an inorganic layer comprising multiple layers thereof; and a first adhesive layer disposed on the flat upper and side surfaces of the inorganic layer; the capping layer disposed adjacent to the trench pattern is recessed inward relative to the cathode; The step reduction layer includes an organic resin and a getter, The inorganic layer is disposed so as to be in contact with a part of the upper surface and side surfaces of the bank and a part of the upper surface of the planarizing layer.

2. The electroluminescent display device of claim 1 , wherein the step reducing layer is implemented as a film.

3. 2. The electroluminescent display device of claim 1, wherein the getter is made of particles having a size of 50 to 100 nm.

4. The electroluminescent display device of claim 1 , wherein the cathode disposed outside the trench pattern is disposed to cover a side surface of the organic layer.

5. 10. The electroluminescent display device of claim 1, wherein the getter comprises at least one of barium oxide (BaO), magnesium oxide (MgO), magnesium sulfate (MgSO), sodium oxide (NaO), sodium sulfate (NaSO), lithium sulfate (LiSO), calcium sulfate (CaSO), potassium oxide (KO), lithium oxide (LiO), gallium sulfate (GaS), calcium chloride (CaCl), magnesium chloride (MgCl), calcium bromide (CaBr), cerium bromide (CeBr), vanadium bromide (VBr), and calcium nitrate (Ca(No)).

6. The electroluminescent display device of claim 1 , wherein the step reduction layer is disposed to contact a portion of the upper surface of the capping layer disposed outside the trench pattern.

7. 2. The electroluminescent display device of claim 1, wherein the step reduction layer covers the capping layer and the cathode disposed outside the trench pattern, and is disposed to contact a portion of the upper surface of the bank extending outside the capping layer and the cathode.

8. The electroluminescent display device according to claim 7 , wherein the inorganic layer is disposed so as to be in contact with the upper surface and side surface of the step reduction layer and another part of the upper surface of the bank.

9. 2. The electroluminescent display device of claim 1, wherein the step reduction layer covers the capping layer, the cathode, and the bank that are disposed outside the trench pattern, and is disposed to contact a portion of the top surface of the planarization layer that extends outside the bank.

10. The electroluminescent display device of claim 9 , wherein the inorganic layer is disposed so as to be in contact with an upper surface and a side surface of the step reduction layer and another part of the upper surface of the planarization layer.

11. The electroluminescent display device of claim 10 , wherein the inorganic layer extends to the non-display area so that a side surface of the inorganic layer is exposed.

12. The electroluminescent display device of claim 1 , wherein an end of the cathode disposed adjacent to the trench pattern has an upwardly raised or curled shape.

13. The electroluminescent display device of claim 12 , wherein the end of the cathode is spaced apart from the organic layer.

14. The electroluminescent display device of claim 13 , wherein the step reducing layer fills a space between the cathode and the organic layer.

15. The electroluminescent display device of claim 1 , further comprising a multi-layered sealing member and a reinforcing substrate disposed on the inorganic layer.

16. The sealing member is the first adhesive layer; a second adhesive layer facing the reinforcing substrate; and The electroluminescent display device of claim 15 , further comprising a barrier layer disposed between the first adhesive layer and the second adhesive layer.

17. The electroluminescent display device of claim 15 , wherein the inorganic layer extends to edges of the sealing member and the reinforcing substrate.

18. The electroluminescent display device of claim 17 , wherein the inorganic layer has exposed sides.

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