Display panel and display device having the same features

Abstract

A display panel (200) has a front region (FA) comprising a display area (AA) and a non-display area (NAA) outside the display area (AA), a rear region (BA) below the front region (FA), and a flexible region (BDA) connected between the front region (FA) and the rear region (BA). The display panel (200) is curved in the flexible region (BDA) and comprises: an organic insulating layer arranged in the front region (FA), the rear region (BA), and the flexible region (BDA), which has a curvature in the flexible region (BDA); and a signal line (CNL) on the organic insulating layer in the flexible region (BDA). The organic insulating layer may have multiple regions having different thicknesses in the flexible region (BDA).

Description

BACKGROUND Area The present disclosure relates to a display panel and a display device comprising the same. Description of related technology A display device is used in various electronic devices, such as televisions, smartphones, laptops, and tablets. Research is being conducted to develop a thin, lightweight, and energy-efficient display device. Examples of the display device include an LCD (liquid crystal display) device, a FED (field emission display) device, and an OLED (organic light-emitting display) device. A bezel of the display device may include an area surrounding the outer surface of a display panel. The bezel can protect the edges of the display panel and internal electronic components from external impact, pressure, or damage. The bezel may be visually perceptible to a user and thus may diminish the sense of immersion in an image emitted by the display. Accordingly, there has recently been an increasing need for a display device that implements a narrow bezel with a reduced bezel area that does not show any display of the display device, or a zero bezel, which essentially has the effect of having no bezel area. EXPLANATION When a flexible substrate is used in a display panel, the panel can have a bendable area where a section of the panel is bent to conceal a pad area beneath the display. The bendable area may be located on the bottom side of the display panel in a top view. The display area can have multiple signal lines to transmit different signals to pixels of the display area. If the flexible section is bent to position itself beneath the display panel to implement a narrow bezel or zero bezel, stress may be exerted on it. This stress can cause cracks in signal lines located within the flexible section, potentially damaging them. Damaged signal lines can make it difficult to transmit signals or power to the display, thus increasing the failure rate of the display device. Accordingly, the inventors of the present disclosure have, through various experiments, invented a display device capable of preventing or suppressing the occurrence of a weak point where load / stress is / becomes concentrated when a bendable area is / becomes bent. One objective to be achieved according to one or more embodiments of the present disclosure is to provide a display device that is capable of preventing or protecting signal lines from being damaged by stress / voltage applied to a flexible area. Another purpose to be achieved according to one or more embodiments of the present disclosure is to provide a display device that is able to reduce a border area while increasing the stiffness / strength of the bendable area. The purposes according to various embodiments of this disclosure are not limited to those mentioned above. Other purposes and advantages according to this disclosure, which are not specifically mentioned, can be understood by a person skilled in the art based on the following descriptions and can be understood more clearly based on exemplary embodiments according to this disclosure. Furthermore, the purposes and advantages according to various embodiments of this disclosure can be understood or realized using means shown in the claims or combinations thereof. To achieve these objectives and other advantages, and in accordance with the purpose of this disclosure as embodied and described in detail herein, a display panel according to claim 1 is provided. Further embodiments are described in the dependent claims.A display panel according to one or more exemplary embodiments of the present disclosure has a front region comprising a display area and a non-display area outside the display area, a rear region below the front region, and a flexible region connecting the front region and the rear region, wherein the display panel is curved in the flexible region and comprises: an organic insulating layer arranged in the front region, the rear region, and the flexible region, which has a curvature in the flexible region; and a signal line on the organic insulating layer in the flexible region, wherein the organic insulating layer has a plurality of regions having different thicknesses in the flexible region. According to one or more embodiments of the present disclosure, the organic insulating layer arranged beneath the signal conductor and within the bendable region comprises a plurality of regions spaced apart from one another and located within the bendable region, the plurality of regions of the organic insulating layer having different thicknesses. In this respect, the organic insulating layer can be a planarizing layer or a substrate. This can prevent or reduce the occurrence of a region within the bendable region where a load / stress is concentrated due to asymmetric curvature of the substrate during a bending operation. The stiffness / strength of the flexible area of ​​the non-display area of ​​the substrate can be increased, thereby preventing or suppressing defects, such as cracks, in the signal line extending from the display area across the flexible area to the pad area. According to one or more embodiments of the present disclosure, the organic insulating layer arranged beneath the signal conductor and within the flexible region comprises a plurality of regions spaced apart from one another and arranged within the flexible region, the plurality of regions of the organic insulating layer having different thicknesses. In this respect, the organic insulating layer can be a planar layer or a substrate. Thus, the curvature of the signal conductor can be adapted to prevent or suppress the occurrence of a stress / load point. This can prevent or protect the signal line from being damaged under the stress / tension during the bending process of the bendable area. This can increase the strength / stiffness of the bendable area while further reducing the visually detectable enclosure area. According to exemplary embodiments of the present disclosure, the defect rate of the display device due to damage to the signal line can be reduced, so that the production energy required for the additional production of the display device can be reduced, thereby reducing greenhouse gas emissions. The effects of the present disclosure are not limited to those mentioned above, and other effects not mentioned can be clearly understood by a person skilled in the art from the description set out below. In addition to the effects mentioned above, specific effects of this revelation are described together in the description of specific details for implementing the example implementations of this revelation provided below, or can be understood from them. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the present disclosure and which are incorporated into and form part of this application, represent exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the disclosure. Figures 1 and 2 are representations depicting a display device according to exemplary embodiments of the present disclosure. Figure 3 is a cross-sectional view taken along line II' in Figure 1. Figure 4 is an exemplary cross-sectional view along line II-II' in Figure 2. Figure 5 is a representation depicting region III from Figure 4. Figures 6 and 7 are representations depicting a display device according to another exemplary embodiment of the present disclosure.Figure 8 is a representation showing a bendable area according to another exemplary embodiment of the present disclosure. Figure 9 is a representation showing a bendable area according to yet another exemplary embodiment of the present disclosure. Figures 10 and 11 are representations showing a load / stress during a bending process. Figure 12 is a representation showing a bendable area according to yet another exemplary embodiment of the present disclosure. DETAILED DESCRIPTION The advantages and features / characteristics of the present disclosure and a method for achieving these advantages and features / characteristics will become apparent with reference to exemplary embodiments, which are described in detail below together with the accompanying drawings. However, the present disclosure is not limited to the exemplary embodiments disclosed below, but can be implemented in various other forms. Thus, these embodiments are presented only to make the present disclosure more complete and to provide a person skilled in the art in the technical field to which the present disclosure belongs with a more complete understanding of the scope of the present disclosure. The protected scope of the present disclosure may be defined by the scope of the claims and their equivalents. For the sake of simplicity and clarity, elements in the drawings are not necessarily drawn to scale. The same reference symbols in different drawings represent the same or similar elements and, as such, fulfill a similar function unless otherwise indicated. Furthermore, descriptions and details of well-known steps and elements may be omitted for the sake of simplicity. Additionally, numerous specific details may be presented in the following detailed description of example implementations of the present revelation to provide a thorough understanding of the present revelation. However, it is understood that the present revelation can be practiced without these specific details.In other cases, well-known methods, processes, components, and circuits cannot be described in detail in order to avoid unnecessarily obscuring aspects of the present disclosure. Examples of various embodiments are presented and described below. It should be understood that the description herein is not intended to limit the claims to the specific embodiments described. On the contrary, it is intended to cover alternatives, modifications, and equivalents that may be contained within the spirit and scope of the present disclosure, as defined by the appended claims and their equivalents. Any shape, size, ratio, angle, number, etc., disclosed in the drawings to illustrate exemplary embodiments of the present disclosure are explanatory, and the present disclosure is not limited thereto. The terminology used herein is solely for the purpose of describing certain embodiments and is not intended to be limiting to the present disclosure. As used herein, the singular represents "one," and "one" is intended to include the plural unless the context clearly indicates otherwise. It should further be understood that terms such as "have," "having," "containing," and "containing," when used in this disclosure, specify the presence of the indicated features / properties, integers, steps, elements, and / or components, but do not exclude the presence or addition of one or more other features / properties, integers, steps, elements, components, and / or sections thereof.As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed elements. An expression such as "at least one of" when preceding a list of elements can modify the entire list of elements and not the individual elements of the list. An error or tolerance may occur in the interpretation of numerical values, even if there is no explicit description of it. Furthermore, it should also be understood that when a first element or layer is described as being "on" a second element or layer, the first element may be arranged directly on the second element or indirectly on the second element, with a third element or layer positioned between the first and second elements or between the first and second layers. It should also be understood that when an element or layer is described as "connected to" or "coupled with" another element or layer, it may be directly connected or coupled to the other element or layer, or there may be one or more intervening elements or layers between them.Furthermore, it should also be understood that when an element or layer is described as being “between” two elements or layers, it may be the only element or layer between the two elements or layers, or there may be one or more intermediate elements or layers. Furthermore, as used herein, where a layer, film, area, plate, or the like is described as being arranged "on" or "above" another layer, film, area, plate, or the like, the former may be in direct contact with the latter, or there may be yet another layer, film, area, plate, or the like arranged between the former and the latter. As used herein, where a layer, film, area, plate, or the like is described as being arranged "directly" on or "above" another layer, film, area, plate, or the like, the former is in direct contact with the latter, and there is no yet another layer, film, area, plate, or the like arranged between the former and the latter.Furthermore, as used herein, where a layer, film, area, plate or the like is described as being arranged 'below' or 'under' another layer, film, area, plate or the like, the former may be in direct contact with the latter, or there may be yet another layer, film, area, plate or the like arranged between the former and the latter.As used herein, where a layer, film, area, plate or the like is described as being arranged “directly” “below” or “under” another layer, film, area, plate or the like, the former is in direct contact with the latter, and there is not yet another layer, film, area, plate or the like arranged between the former and the latter. When describing temporal relationships, for example, temporally preceding relationships between two events, such as "after", "subsequent", "before", etc., another event may occur in between unless a more specific expression such as "directly after", "directly following" or "directly before" is given. If a particular embodiment can be implemented differently, a function or operation specified in a specific block may occur in a different order than the order specified in a flowchart. For example, two blocks may actually be executed sequentially, essentially simultaneously, or the two blocks may be executed in reverse order, depending on an involved function or operation. It should be understood that, although terms such as "first," "second," "third," and so on may be used herein to describe different elements, components, areas, layers, and / or time periods, these elements, components, areas, layers, and / or time periods are not intended to be limited by these terms. These terms are used to refer to one element, component, area, layer, or time period separately from any other element, component, area, layer, or time period.Thus, a first element, a first component, a first area, a first layer or a first period of time, as described herein, could be referred to as a second element, a second component, a second area, a second layer or a second period of time and vice versa, without deviating from the content and scope of the present disclosure. The features / properties of the various embodiments of the present disclosure may be partially or completely combined and may be technically associated with one another or work together. The embodiments may be implemented independently of one another or may be implemented together in an associative relationship. When interpreting a numerical value, the value should be interpreted as including an error range, unless otherwise specified. Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as they are normally understood by a person skilled in the art in the field to which this disclosure belongs. Furthermore, it should be understood that terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and are not to be interpreted in an idealized or overly formal sense, unless expressly defined as such herein. As used herein, “elaborations”, “examples”, “aspects” and the like shall not be construed as implying that any embodiment, example, aspect or design as described is / are superior or advantageous to any other embodiment, example, aspect or design. Furthermore, unless otherwise stated or clear from the context, the term "or" means "inclusive or" rather than "exclusive or". That is, unless otherwise stated or clear from the context, the expression means that "xa or b uses" one of the natural inclusive permutations. The terms used in the following description were chosen as general and universal within the related technical field. However, other terms that are essentially the same, similar, or suitable may exist, depending on the development and / or change of technology, convention, technician preference, etc. Therefore, the terms used in the following description should not be understood as restrictive technical concepts, but rather as examples of terms used to describe embodiments. Furthermore, in a specific case, a term may be arbitrarily chosen by the applicant, and in this case, its detailed meaning will be described in a corresponding description period. Therefore, the terms used in the following description should be understood not simply based on their names, but on their meaning and content as presented in the detailed description. In the description of a signal flow, for example, when a signal is described as being delivered from node A to node B, this may include a case where the signal is transmitted from node A to node B via another node, unless a more specific expression such as "immediately transmitted" or "directly transmitted" is used. Throughout this entire disclosure, where used, “A and / or B” means A, B or A and B unless otherwise specified, and “C to D” means C inclusive to D inclusive unless otherwise specified. "At least one" should be understood to include any combination of one or more of the listed components. For example, "at least one of a first, a second, and a third component" includes not only a first, a second, or a third component individually, but also all combinations of two or more of the first, the second, and the third component. The following are examples of embodiments of this disclosure with reference to the accompanying drawings. The scale of each component, as shown in the drawings, may differ from an actual scale for the sake of clarity. Therefore, this disclosure is not limited to the scale shown in the drawings. As used herein, a first direction, a second direction and a third direction, or an X-axis direction, a Y-axis direction and a Z-axis direction, shall not only be interpreted as having a geometric relationship to each other in which the first direction, the second direction and the third direction are perpendicular to each other, or the X-axis direction, the Y-axis direction and the Z-axis direction are perpendicular to each other, but may also be interpreted as having a geometric relationship to each other in which the first direction, the second direction and the third direction are of interest to each other at an angle other than 90 degrees (°), or the X-axis direction, the Y-axis direction and the Z-axis direction are of interest to each other at an angle other than 90 degrees (°) within a range in which a configuration of the present disclosure can operate functionally. A display device according to exemplary embodiments of the present disclosure is described below with reference to the drawings. Figures 1 and 2 are illustrations depicting a display device according to exemplary embodiments of the present disclosure. Figure 1 shows a state in which the example display device is not bent, and Figure 2 shows a state in which the example display device is bent. As shown in Fig. 1 and Fig. 2, a display device 1 according to an exemplary embodiment of the present disclosure can have a display panel 200 comprising a display area AA and a non-display area NAA, a control circuit chip 103, a printed circuit board 104, etc. The display area AA is an area in which an image is displayed, and a plurality of pixels P, data lines DL, and gate lines GL may be arranged in the display area AA. The non-display area NAA may be an area in which no image is displayed. The non-display area NAA may be located in the perimeter (or edge) region of the display panel 200. However, embodiments of the present disclosure are not limited thereto. For example, an area other than a light-emission region, in which light is emitted outwards in the display area AA, may be designated as the non-display area NAA. A border region of the display device may be defined by means of the non-display area NAA. The border region or the non-display area NAA may surround the outside of the display area AA.A flexible area (BDA) and a pad area (PDA) can be located at the lower end of the non-display area (NAA). Lines for supplying an electrical signal to the display area AA or for receiving an electrical signal from the display area AA can be arranged in the non-display area NAA. For example, a gate driver for supplying a gate signal to the plurality of sub-pixels SP1, SP2, and SP3 of the display area AA can be arranged in the non-display area NAA. The gate driver can be arranged at either a right or left edge of the non-display area NAA in a gate-in-panel (GIP) manner, but embodiments of the present disclosure are not limited thereto. The gate driver can transmit a gate signal via the gate lines GL. The non-display area NAA can include a driver chip 103 in a pad area PDA in which a plurality of pads are arranged. The driver chip 103 can transmit a data signal to the plurality of sub-pixels SP1, SP2, and SP3 via the plurality of data lines DL in the display area AA. For example, the driver chip 103 can be a data driver chip. However, embodiments of the present disclosure are not limited to this. The gate lines GL can extend in a first direction X of the display panel 200, and the data lines DL can intersect the gate lines GL and extend in a second direction Y of the display panel 200 in a top view of the display device. The data lines DL in the display area AA can extend towards the flexible area BDA and can be electrically connected to the driver circuit chip 103. In one example, the signal lines that electrically connect the data lines DL and the driver circuit chip 103 can extend from a section of the non-display area NAA between the flexible area BDA and the display area AA to the flexible area BDA and the pad area PDA, thus being electrically connected to the printed circuit board 104. The signal lines extending to the flexible area BDA can be bent along a shape of the flexible area BDA if the flexible area BDA is bent. This will be described later. The flexible area BDA of the display panel 200 can be bent such that the circuit board 104 is positioned below the display area AA of the display panel 200. The circuit board 104 can include a control circuit chip for controlling the gate driver. Accordingly, the non-display area NAA, which is visible to a viewer in front of the display device 1, can be reduced, and a narrow bezel can be implemented. The display area AA can have a plurality of pixels P and one or more holes H. The hole(s) H can be an area in which an electronic component for adding various functions to the display device 1 is arranged. For example, the electronic component can have a camera module for taking a picture or recording, or it can have various sensor devices for detecting an external object. The sensor device can have at least one proximity sensor, a gesture sensor, a color sensor, a biometric sensor, and an infrared sensor. However, embodiments of the present disclosure are not limited thereto. A pixel P can have a plurality of sub-pixels SP1, SP2, and SP3. An image can be displayed in the display area AA by means of this plurality of sub-pixels SP1, SP2, and SP3. The plurality of sub-pixels SP1, SP2, and SP3 can be arranged in an array within the display area AA. In one example, the plurality of sub-pixels SP1, SP2, and SP3 can be arranged in a matrix and can be spaced apart from each other in the first direction of the display area AA and in the second direction, which intersects the first direction. The first direction can be a horizontal direction, an X-axis direction, or a row direction, and the second direction can be a vertical direction, a Y-axis direction, or a column direction. However, the present disclosure is not limited to this, and the arrangement, order, and direction of the sub-pixels SP1, SP2, and SP3 can be modified in various ways. The sub-pixels SP1, SP2, and SP3 can be implemented to emit light of the same color, such as white light. Alternatively, the sub-pixels SP1, SP2, and SP3 can be implemented to emit light of different colors, such as red, green, and blue. Fig. 3 is a cross-sectional view taken along line II' in Fig. 1. Fig. 3 schematically represents an example sub-pixel of a display device. For the sake of expediency, this disclosure describes an example of a sub-pixel configuration. However, this disclosure is not limited to such an example. As shown in Fig. 3, the display panel 200 can have a control array 1000 arranged on the substrate 201. A polarizing layer 300, an optical adhesive element 310 and a cover substrate 400 can be arranged on the control array 1000. The control array 1000 can include a pixel control circuit 1100, a light-emitting area 1200, and a touch area 1300. The pixel control circuit 1100 can include a plurality of transistors 220 and 240 and a storage capacitor 230. The light-emitting area 1200 can include a light-emitting element 260, and the touch area 1300 can include a touch sensor 287. A sub-pixel can have the light-emitting area 1200, which includes the light-emitting element 260 and the pixel control circuit 1100, which applies a control current to the light-emitting element 260 of the light-emitting area 1200. The pixel control circuit 1100 is arranged on the substrate 201, and the light-emitting area 1200 is arranged on the pixel control circuit 1100. The touch area 1300 can be arranged on the light-emitting area 1200. However, embodiments of the present disclosure are not limited thereto. The plurality of transistors 220 and 240 of the pixel control circuit 1100 can include a first transistor 220 and a second transistor 240. The substrate 201 can be a flexible plastic substrate. If the substrate 201 is formed as a single plastic layer, it can have multiple layers made of an insulating material. A first buffer layer 205 can be arranged on the substrate 201. The first buffer layer 205 can cover an area of ​​the substrate 201. The first buffer layer 205 can reduce or prevent the penetration of moisture, oxygen, or contaminants through the substrate 201. The first buffer layer 205 can be a single layer or a multiple layer made of an inorganic insulating material, such as silicon dioxide (SiOx) or silicon nitride (SiNx). The first buffer layer 205 can completely cover the area of ​​the substrate 201 in the display area AA.For example, the first buffer layer 205 can extend to the non-display area NAA, which surrounds the perimeter of the display area AA. A light-shielding layer 209 can be arranged on the first buffer layer 205. The light-shielding layer 209 can prevent or block external light from reaching the transistor. For this purpose, the light-shielding layer 209 can be made of an opaque metallic material. A second buffer layer 212 can be arranged on the light-shielding layer 209. The second buffer layer 212 can protect the transistor from moisture, oxygen, or impurities. The second buffer layer 212 can be a single layer or a multiple layer made of an inorganic insulating material, such as silicon dioxide (SiOx) or silicon nitride (SiNx). However, embodiments of the present disclosure are not limited to these. The second buffer layer 212 can completely cover the area of ​​the substrate 201 in the display area AA.For example, the second buffer layer 212 can extend to the non-display area NAA, which surrounds the perimeter of the display area AA. The first transistor 220 can be arranged on the second buffer layer 212. The first transistor 220 can have a first semiconductor layer 221, a first gate insulating layer 222, a first gate electrode 223, a first source electrode 224, and a first drain electrode 225. In one example, the first transistor 220 can be a switching transistor. The first semiconductor layer 221 can have a channel region and source / drain regions. A region of the first semiconductor layer 221 that overlaps the first gate electrode 223 in the vertical direction can be a channel region. The source / drain regions can be arranged in an associated manner on opposite sides of the channel region. The first semiconductor layer 221 can have one of a polysilicon semiconductor layer and a low-temperature polysilicon semiconductor layer, or a combination thereof. In another example, the first semiconductor layer 221 can have an oxide semiconductor layer. For example, the first semiconductor layer 221 can have at least one of an oxide semiconductor material, such as IGZO (indium gallium zinc oxide) or IZO (indium zinc oxide). Where / If the first semiconductor layer 221 has the oxide semiconductor layer, the first transistor 220 can be designed as an oxide thin-film transistor. The first semiconductor layer 221 can be arranged to overlap the light-shielding layer 209 in the vertical direction. The light-shielding layer 209 can prevent or block external light from falling on the first semiconductor layer 221. The first gate insulating layer 222 can be positioned between the first semiconductor layer 221 and the first gate electrode 223. The first gate insulating layer 222 can extend outwards while covering the first semiconductor layer 221. The first gate insulating layer 222 can be a single layer or a stack of multiple layers made of an inorganic insulating material, such as silicon dioxide (SiOx) or silicon nitride (SiNx). The first gate insulating layer 222 can completely cover the area of ​​the substrate 201 in the display area AA. For example, the first gate insulating layer 222 can extend to the non-display area NAA, which surrounds the perimeter of the display area AA. The first gate electrode 223 can be arranged on the first gate insulating layer 222. A first interlayer insulating layer 214 can be arranged on the first gate electrode 223. The first interlayer insulating layer 214 can be a single layer or a stack of multiple layers made of an inorganic insulating material, such as silicon dioxide (SiOx) or silicon nitride (SiNx). In one example, the first interlayer insulating layer 214 can extend to the non-display area NAA, which surrounds the perimeter of the display area AA. The first source electrode 224 and the first drain electrode 225 can be electrically connected to the first semiconductor layer 221. The storage capacitor 230 can have a first storage electrode 231 and a second storage electrode 232. For example, the first storage electrode 231 and the first gate electrode 223 can be formed on the same layer (e.g., the first gate insulating layer 222). The first storage electrode 231 can be located on the first gate insulating layer 222 at a horizontal distance from the first gate electrode 223. The first storage electrode 231 can be made of the same material as the first gate electrode 223. The second storage electrode 232 can be positioned on the first intermediate insulating layer 214 such that it overlaps the first storage electrode 231 in the vertical direction. Each of the first storage electrode 231 and the second storage electrode 232 can be configured as a single layer or as a stack of multiple layers made of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof. However, embodiments of the present disclosure are not limited thereto. A second interlayer insulating layer 216 can be arranged on the second storage electrode 232. The second interlayer insulating layer 216 can be configured as a single layer or a stack of multiple layers made of an inorganic insulating material, such as silicon dioxide (SiOx) or silicon nitride (SiNx). In one example, the second interlayer insulating layer 216 can extend to the non-display area NAA, which surrounds the perimeter of the display area AA. The second transistor 240 can be arranged on the second intermediate insulating layer 216 such that it is separated from the first transistor 220 by a distance. The second transistor 240 can be electrically connected to the first transistor 220. For example, the second transistor 240 can have a second semiconductor layer 241, a second gate insulating layer 242, a second gate electrode 243, a second source electrode 245, and a second drain electrode 246. In one example, the second transistor 240 can be a drive transistor that is electrically connected to the light-emitting element 260. The second semiconductor layer 241 can have a channel region and source / drain regions. A region of the second semiconductor layer 241 that overlaps the second gate electrode 243 in the vertical direction can be a channel region. The source / drain regions can be arranged in an associated manner on opposite sides of the channel region. The second semiconductor layer 241 can have an oxide semiconductor layer. For example, the second semiconductor layer 241 can have an oxide semiconductor material, such as indium gallium zinc oxide (IGZO) or indium zinc oxide (IZO). In one example, the second semiconductor layer 241 can be arranged to overlap the storage capacitor 230 in the vertical direction. Accordingly, the storage capacitor 230 can prevent or block the external light entering through the substrate 201 from reaching the second semiconductor layer 241.Accordingly, this can prevent or protect the properties of the second transistor 240 from being changed by the external light. The second gate insulating layer 242 can be positioned between the second semiconductor layer 241 and the second gate electrode 243. The second gate insulating layer 242 can extend outwards while covering the second semiconductor layer 241. For example, the second gate insulating layer 242 can extend to the non-display area NAA, which surrounds the perimeter of the display area AA. The second gate insulating layer 242 can be a single layer or a stack of multiple layers made of an inorganic insulating material, such as silicon dioxide (SiOx) or silicon nitride (SiNx). Each of the first gate electrode 223 or the second gate electrode 243 can be configured as a single layer or a stack of multiple layers made of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof. However, the material is not limited to these. A third interlayer insulating layer 218 can be arranged on the second gate electrode 243. The third interlayer insulating layer 218 can comprise an insulating material. For example, the third interlayer insulating layer 218 can comprise an inorganic insulating material, such as silicon oxide (SiOx), silicon nitride (SiNx), or silicon oxynitride (SiON), and can be implemented as a single layer or a stack of multiple layers. In one example, the third interlayer insulating layer 218 can extend to the non-display area NAA, which surrounds the perimeter of the display area AA. The first source electrode 224, the first drain electrode 225, the second source electrode 245 and the second drain electrode 246 can be arranged on the third interlayer insulating layer 218. The first source electrode 224 and the first drain electrode 225 can extend through the third interlayer insulating layer 218, the second gate insulating layer 242, the second interlayer insulating layer 216, the first interlayer insulating layer 214 and the first gate insulating layer 222 in such a way that they are in direct contact and electrically connected in an associated manner with the source / drain regions of the first semiconductor layer 221. The second source electrode 245 and the second drain electrode 246 can extend through the third interlayer insulating layer 218 and the second gate insulating layer 242 such that they are in direct contact and electrically connected to the source / drain regions of the second semiconductor layer 241. The second drain electrode 246 of the second transistor 240 can be electrically connected to the storage capacitor 230. For example, a section of the second drain electrode 246 can extend through the third interlayer insulating layer 218, the second gate insulating layer 242, the second interlayer insulating layer 216, and the first interlayer insulating layer 214 such that it is in direct contact and electrically connected to the first storage electrode 231 of the storage capacitor 230. Each of the first source electrode 224, the first drain electrode 225, the second source electrode 245, and the second drain electrode 246 can be configured as a single layer or a stack of multiple layers made of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof. However, embodiments of the present disclosure are not limited thereto. In one example, each of the first source electrode 224 and the first drain electrode 225 can have a stacked structure of titanium layer / aluminum layer / titanium layer (Ti / Al / Ti). A passivation layer 247 can be arranged on the first source electrode 224, the first drain electrode 225, the second source electrode 245, and / or the second drain electrode 246. The passivation layer 247 can comprise an inorganic insulating material, such as silicon oxide, silicon nitride, and silicon oxynitride, and can be implemented as a single layer or a stack of multiple layers. The passivation layer 247 can protect the underlying pixel driver circuitry. The passivation layer 247 can extend to the non-display area NAA, which surrounds the perimeter of the display area AA. The inorganic insulating layers 205, 212, 222, 214, 216, 242, 218, and 247 arranged on the substrate 201 can be vertically stacked in the non-display area NAA to form an inorganic insulating structure MB (see also, for example, Fig. 5). For instance, the inorganic insulating structure MB can comprise the first buffer layer 205, the second buffer layer 212, the first gate insulating layer 222, the first intermediate insulating layer 214, the second intermediate insulating layer 216, the second gate insulating layer 242, the third intermediate insulating layer 218, and the passivation layer 247. However, embodiments of the present disclosure are not limited to these. A planarization layer 250 can be arranged on the passivation layer 247. The planarization layer 250 can planarize one or more levels caused by the pixel-drive circuitry below it. The planarization layer 250 can have a multilayer structure consisting of a first planarization layer 251 and a second planarization layer 252. For example, the planarization layer 250 can comprise a photoreactive organic insulating material, such as a photosensitive polyimide resin, a photoacrylic resin, or a photosensitive photoresist. In one example, each of the first planarization layer 250 and the second planarization layer 251 can extend to the non-display area NAA, which surrounds the perimeter of the display area AA. A pixel contact electrode 255 can be arranged on the first planarization layer 251. The pixel contact electrode 255 can extend through the first planarization layer 251 and the passivation layer 247 such that it is in direct contact with the second drain electrode 246 of the second transistor 240. The light-emitting element 260 can be formed on the planarization layer 250. For example, the light-emitting element 260 can be arranged on the second planarization layer 252. The light-emitting element 260 can have a first electrode 261, a light-emitting layer 263, a second electrode 265, and a cover layer 267. The light-emitting element 260 can be electrically connected to the pixel control circuit via the first electrode 261. For example, the first electrode 261 can extend through the second planarization layer 252 such that it is in direct contact with the pixel contact electrode 255. Accordingly, the first electrode 261 can be electrically connected to the second transistor 240 via the pixel contact electrode 255. The pixel contact electrode 255 can be made of a conductive material. For example, the pixel contact electrode 255 can be made of a metallic material such as aluminum (Al), chromium (Cr), copper (Cu), titanium (Ti), molybdenum (Mo), or tungsten (W). In one example, the pixel contact electrode 255 can have a multilayer structure consisting of titanium / aluminum / titanium (Ti / Al / Ti). The first electrode 261 can have a transparent conductive layer. For example, the first electrode 261 can have ITO (indium tin oxide) or IZO (indium zinc oxide). Alternatively, the first electrode 261 can have a single-layer or multi-layer structure comprising a reflective metal layer made of silver (Ag), aluminum (Al), gold (Au), nickel (Ni), and chromium (Cr), or an alloy thereof. The first electrode 261 can also be referred to as a pixel electrode or an anode electrode. A bank 262 can be arranged on the first electrode 261. The bank 262 can be arranged to cover an edge of the first electrode 261. A section of the bank 262 can extend to the second planarization layer 252. A section of an upper surface of the first electrode 261 that is not covered by the bank 262, and is therefore exposed by the bank 262, can be the light emission area. The bank 262 can be made of an organic insulating material. For example, the bank 262 can be made of photosensitive polyimide, photoacrylic, or benzocyclobutene (BCB). A spacer element 264 can further be arranged on the bench 262. The spacer element 264 can be arranged to prevent or suppress damage to the bench 262 and the first electrode 261 during the manufacturing or production process. The spacer element 264 can be made of the same material as the bench 262. The bench 262 and the spacer element 264 can be stacked vertically to form an organic insulating structure 266. The light-emitting layer 263 can be arranged on the first electrode 261. The light-emitting layer 263 can comprise a hole transport layer (HTL), an organic light-emitting layer (EML), an electron transport layer (ETL), a hole blocking layer (HBL), a hole injection layer (HIL), an electron blocking layer (EBL), and an electron injection layer (EIL). The light-emitting layer 263 can have a multi-stack structure in which two or more organic emission layers (EML) are stacked. The second electrode 265 can be arranged on the light-emitting layer 263. The second electrode 265 can be connected to the light-emitting layer 263, which is formed in all pixels. Therefore, the second electrode 265 can also be referred to as a common electrode or a cathode electrode. The second electrode 265 can have a transflective conductive material. For example, the second or cathode electrode 265 can be made of a metallic material, such as magnesium (Mg), silver (Ag), or an alloy (Ag-Mg) of silver (Ag) and magnesium (Mg). Alternatively, the second electrode 265 can have a transparent conductive layer, such as indium tin oxide (ITO) or indium zinc oxide (IZO). The cover layer 267 can be arranged on the second electrode 265. The cover layer 267 can prevent light generated by the light-emitting layer 263 from being lost, thereby improving the light extraction efficiency. The encapsulation stack 270 can be arranged on the light-emitting element 260. The encapsulation stack 270 can protect the light-emitting element 260 from external oxygen or moisture. The encapsulation stack 270 can extend to the non-display area NAA outside the display area AA while covering the display area AA. The encapsulation stack 270 can have a multi-layer structure in which a first encapsulation layer 271, a second encapsulation layer 273, and a third encapsulation layer 275 are stacked. The second encapsulation layer 273 can be arranged between the first encapsulation layer 271 and the third encapsulation layer 275. The first encapsulation layer 271 can be arranged on the cover layer 267. The second encapsulation layer 273 can be arranged on the first encapsulation layer 271. The second encapsulation layer 273 can cover the first encapsulation layer 271 and can have sufficient thickness to form a flat top surface. The second encapsulation layer 273 can prevent or block foreign substances from penetrating the light-emitting element 260. The third encapsulation layer 275 can be arranged on the second encapsulation layer 273. Each of the first encapsulation layer 271 and the third encapsulation layer 275 can extend to the non-display area NAA, which surrounds the perimeter of the display area AA. Each of the first encapsulation layer 271 and the third encapsulation layer 275 can comprise an inorganic insulating material, and the second encapsulation layer 273 can comprise an organic insulating material. For example, each of the first encapsulation layer 271 and the third encapsulation layer 275 can comprise at least one of silicon nitride (SiNx), silicon oxide (SiOx), and silicon oxynitride (SiON). The second encapsulation layer 273 can comprise at least one of epoxy, polyimide, polyethylene, and acrylate. The touch area 1300 can be arranged on the encapsulation stack 270. The touch area 1300 can comprise a touch buffer layer 277, a touch sensor 287, a touch intermediate insulating layer 282, a first touch protection layer 290, and a second touch protection layer 295. The touch buffer layer 277 can be arranged on the third encapsulation layer 275. The touch buffer layer 277 can reduce stress / voltage between the encapsulation stack 270 and the touch sensor layer 287 to prevent or protect the encapsulation stack 270 and the light-emitting element 260 from damage. The touch buffer layer 277 can comprise an inorganic insulating material. For example, the touch buffer layer 277 can comprise silicon nitride (SiNx). The touch sensor 287 can have a plurality of touch electrodes 285 and a bridge electrode 281. The plurality of touch electrodes 285 and the bridge electrode 281 can be arranged in different layers. For example, the bridge electrode 281 can be arranged on the touch buffer layer 277. The plurality of touch electrodes 285 can be arranged on the contact intermediate insulating layer 282. The plurality of touch electrodes 285 can have a first touch electrode 283 and a second touch electrode 284. The bridge electrode 281 can electrically connect adjacent first touch electrodes 283 to each other. For this purpose, the first touch electrodes 283 can extend through the contact intermediate insulating layer 282 so that they are connected to the bridge electrode 281. The contact intermediate insulating layer 282 can have an inorganic insulating material.For example, the contact interlayer insulating layer can contain silicon nitride (SiNx). The first contact electrode 283, the second contact electrode 284, or the bridge electrode 281 can comprise a conductive material. The first contact electrode 283, the second contact electrode 284, or the bridge electrode 281 can comprise a single layer or a stack of multiple layers made of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof. Each of the contact buffer layer 277 and the contact intermediate insulating layer 282 can extend to the non-display area NAA. The contact buffer layer 277 and the contact intermediate insulating layer 282 can touch each other in the vertical direction in the non-display area NAA such that they form a contact insulating structure 280. The first touch protection layer 290 can be arranged on the touch sensor 287. The first touch protection layer 290 can prevent or suppress damage to the touch sensor 287 from external impact / shock and moisture. The first touch protection layer 290 can comprise an organic insulating material. For example, the first touch protection layer 290 can be made of a photosensitive acrylic-based or polyimide-based organic material. The second touch protection layer 295 can be arranged on top of the first touch protection layer 290. The second touch protection layer 295 can further protect the touch sensor 287 from external impact and moisture. Additionally, the second touch protection layer 295 can planarize one or more steps caused by the structure forming the underlying touch sensor 287. The second touch protection layer 295 can comprise an organic insulating material. A polarizing layer 300 can be arranged on the second contact protection layer 295 of the contact area 1300. The polarizing layer 300 can be arranged on the contact area 1300 via a first adhesive element 305. The polarizing layer 300 can suppress reflection of external light and can change the polarization state of light emitted by the light-emitting element 260 of the light-emitting area 1200. For example, the first adhesive element 305 can have a pressure-sensitive adhesive (PSA). A cover substrate 400 can be arranged on the polarizing layer 300. The cover substrate 400 can protect the pixel control circuit 1100, the light-emitting area 1200, and the touch area 1300. The cover substrate 400 can be referred to as a cover window, a window cover, or a cover glass. The cover substrate 400 can be an example of a cover element. The cover substrate 400 can be a glass substrate. An optical adhesive element 310 can be arranged between the polarizing layer 300 and the cover substrate 400. For example, the optical adhesive element 310 can have an optically clear adhesive (OCA) layer. Fig. 4 is a representation showing an example cross-sectional view taken along line II-II' in Fig. 2. Fig. 5 is a representation showing area III from Fig. 4. As shown in Figs. 4 and 5, the substrate 201 of the display panel 200 can have a front area FA on which an image is displayed, a rear area BA arranged to face a rear surface of the front area FA, and a flexible area BDA located between the front area FA and the rear area BA. The front area FA can have a display area AA and a non-display area NAA, which is different from the display area AA. The display area AA and the non-display area NAA can be used interchangeably on a cover substrate 400. An area of ​​the cover substrate 400 through which an image is displayed can be the display area AA. The flexible area BDA can extend from one side of the front area FA of the display panel 200 (or the substrate 201) and can be flexible. When the flexible area BDA of the display panel 200 (or the substrate 201) has been bent, the printed circuit board 104 can be positioned in the rear area BA and facing away from the front area FA. A first adhesive element 305, a polarizing layer 300, an optical adhesive element 310 and the cover substrate 400 can be arranged on the display panel 200. Plates 500 and 510 can be arranged on a lower surface of the substrate 201 of the display panel 200. The plates 500 and 510 can hold the substrate 201, which is made of a flexible material, to maintain its shape. The plates 500 and 510 can, for example, be made of polyethylene terephthalate (PET). The plates 500 and 510 can have a first plate 500 and a second plate 510, which are spaced apart from each other. The first plate 500 and the second plate 510 can be located in a different area than the bendable area BDA, so that the bendable area BDA of the display panel 200 can be easily bent. For example, the bendable area BDA can be located in the area between the first plate 500 and the second plate 510. For example, one end of the first plate 500 can be a boundary / limit on one side of the flexible area BDA, and one end of the second plate 510, facing the end of the first plate 500, can be a boundary / limit on the other side of the flexible area BDA. The first plate 500 can contain the display area AA and a portion of the non-display area NA adjacent to the display area AA, while the second plate 510 can contain a portion of the substrate 201 of the display panel 200 on which the printed circuit board 104 is mounted. For example, because the first plate 500 is located in an area corresponding to and vertically overlapping the display area AA, the first plate 500 can be larger than the second plate 510 in the top view of the display device. A third plate 520 can be arranged beneath the first plate 500. In one example, the third plate 520 can have a heat dissipation layer. The heat dissipation layer is designed to provide a heat dissipation effect to deal with a component that generates heat and can be made of a material with high thermal conductivity. For example, the third plate 520 can be made of a metal material that has high thermal conductivity. A connecting element 530 can be arranged on top of the second plate 510. The connecting element 530 can fix a curved section of the display panel 200 to maintain its curved shape. The connecting element 530 can have a pressure-sensitive adhesive that is optically transparent and capable of fixing the third plate 520 and the second plate 510 in place. A first adhesive layer 505 can be arranged between the first plate 500 and the substrate 201 of the display panel 200, and between the second plate 510 and the substrate 201, to fix each of the first plate 500 and the second plate 510 to the substrate 201. A second adhesive layer 525 can be arranged between the first plate 500 and the third plate 520 to fix the first plate 500 and the third plate 520 to each other. A third adhesive layer 515 and a fourth adhesive layer 535 are arranged in an associated manner on a lower and an upper surface of the connecting element 530 to fix the curved section of the display panel 200 in order to maintain its curved shape. A signal line CNL can be arranged on the flexible area BDA of substrate 201. The signal line CNL can be electrically connected to the control array 1000 in the display area AA. The signal line CNL can extend on and along the flexible area BDA in the non-display area NAA and be electrically connected to the circuit board 104. As shown in Fig. 5, an inorganic insulating structure MB can be arranged on a section of the non-display area NAA between the display area AA and the flexible area BDA of substrate 201. The inorganic insulating structure MB can be arranged such that it does not extend to the flexible area BDA. The inorganic insulating structure MB can be configured as an insulating layer of a multilayer structure made of an inorganic insulating material and extending from the display area AA (see, for example, Fig. 3). A connecting contact electrode LCT can be arranged on the inorganic insulating structure MB.The interconnection contact electrode LCT can be made of the same material as the second source electrode 245 or the second drain electrode 246 of the display area AA and can be formed in the same process as the second source electrode 245 or the second drain electrode 246. The interconnection contact electrode LCT can be electrically connected to data link lines that are connected to the majority of pixels P of the display area AA via interconnection electrodes, each extending through the stack of several insulating layers that form the inorganic insulating structure MB. The first planarization layer 251, which covers the connecting contact electrode LCT, can be arranged on the inorganic insulating structure MB. The first planarization layer 251 can extend from the display area AA to the flexible area BDA. For example, the first planarization layer 251 on the flexible area BDA can be arranged so that it is in direct contact with the substrate 201. For example, the first planarization layer 251 can be arranged so that it extends from the front area FA and then across the flexible area BDA to the rear area BA. In this case, the first planarization layer 251 can have the same thickness over the entire flexible area BDA. If a section of the inorganic insulating structure MB, corresponding to and vertically overlapping the flexible area BDA of the display panel, is removed, a section of the substrate 201 located beneath the inorganic insulating structure MB may also be removed to form an inclined surface. The inclined surface formed by removing the section of substrate 201 from the flexible area BDA may have a sharp slope or a steep incline, depending on a process condition. If the inclined surface of substrate 201 has a steep incline, defects may occur in which a section of the signal line CNL located on the sharply inclined surface may be broken or cut off. For this reason, the first planarization layer 251 may be formed on the substrate 201, and the signal line CNL may be located on the first planarization layer 251.This can prevent or suppress the potential defect of the signal line CNL from breaking due to the steep inclination of the substrate 201 in the flexible area BDA. The signal line CNL can be located on the first planarization layer 251. The signal line CNL can be located on the non-display area NAA and the flexible area BDA adjacent to the display area AA. The signal line CNL can extend through the first planarization layer 251 such that it is in contact with and connected to the junction contact electrode LCT. An area in which the signal line CNL and the contact electrode LCT are in contact with and connected to each other can be designated as a junction area CTA. The signal line CNL can be made of the same material as that of the pixel contact electrode 255 of the display area AA and can be formed in the same process as that of the pixel contact electrode 255. The second planarization layer 252 can be arranged on the signal line CNL. The second planarization layer 252 can extend to the flexible area BDA while covering the signal line CNL. For example, the second planarization layer 252 can be arranged to extend from, onto, and along the front area FA, and then over, onto, and along the flexible area BDA, and onto and along the rear area BA. The organic insulating structure 266 can be arranged on the second planarization layer 252. The organic insulating structure 266 can be made of the same material as each of the bench 262 and the spacer element 264, and formed in the same process as each of the bench 262 and the spacer element 264. As shown in Figs. 4 and 5, a protective layer 560 can be arranged on an outer surface of the flexible area BDA of the display panel 200. The protective layer 560 can cover a section of the signal line CNL, which is arranged on the flexible area BDA, and can extend to cover a portion of the front area FA and a portion of the rear area BA. On the front area FA, the protective layer 560 can cover a side surface of the polarizing layer 300. On the rear area BA, the protective layer 560 can cover a portion of the printed circuit board 104. In one example, the protective layer 560 can be thicker than the polarizing layer 300. The protective layer 560 can protect the signal line CNL from external influence / shock and prevent or block moisture from penetrating the signal line CNL. Additionally, the protective layer 560 can increase the stiffness / strength of the substrate 201 of the display panel 200 in the flexible area BDA where the first plate 500 and the second plate 510 are not arranged. For example, the protective layer 560 can comprise resin. However, embodiments of the present disclosure are not limited to this. A small-curvature bending operation (fixed bending operation) can further be performed on the substrate 201 of the display panel 200 to minimize a section (or border area) of the non-display area in a marginal section of the front area FA that may be visible to the viewer in front of the front area FA. In the small-curvature bending operation (fixed bending operation), after the bendable area BDA has been bent, a section of the substrate 201 on which the second plate 510 is arranged can be pulled in a horizontal direction F, as shown in Fig. 4, so that the bendable area has an even smaller radius of curvature, thus minimizing or further reducing the section (or border area) of the non-display area in a marginal section of the front area FA that may be visible to the viewer in front of the front area FA. Before the small-curvature bending operation (fixed bending operation) is performed, the bendable area BDA can have the same radius of curvature over its entire length, so that the rear area BA of the display panel 200 is positioned below the front area FA. However, since the small-curvature bending operation (fixed bending operation) is further performed to minimize or reduce the border area visible to the viewer in front of the front area FA, the shape of the substrate 201 may be altered, resulting in an asymmetrical curvature. For example, if a section of substrate 201, located in the rear region BA, is pulled in the horizontal direction F, one end of the second plate 510 moves in the horizontal direction F, such that one end of the first plate 500 may project beyond the end of the second plate 510 (e.g., further outward than the end of the second plate 510). Accordingly, the curvature of the signal line section CNL, located on the flexible region BDA, may be non-uniform. For example, the curvature of signal line CNL may be asymmetrical, so that radii of curvature R1, R2, and R3 may differ at different positions of the signal line, corresponding to different positions of the flexible region BDA. The radius of curvature represents the amount by which the curve is bent. The radius of curvature at a point on a curve is the radius of the circle that best approximates the curve at that point.It can be considered a measure of how much a curve deviates from a straight line at a specific point. The smaller the radius of curvature, the sharper or more pronounced the bend in the curve. As the radius of curvature decreases, the amount by which the curve is bent can increase. For example, a section of the signal line CNL on a section of the flexible area BDA located near the front area FA can have a first radius of curvature R1 from a geometric location around the end of the first plate 500. Similarly, a section of the signal line CNL located on the furthest projecting section (e.g., the outermost section) of the flexible area BDA can have a second radius of curvature R2 from a geometric location around the end of the third plate 520. Additionally, a section of the signal line CNL located on a section of the flexible area BDA near the rear area BA can have a third radius of curvature R3 from a geometric location around one end of the third plate 520.From the first to the third radius of curvature R1, R2, and R3, the first radius of curvature R1 can be the smallest and the third radius of curvature R3 the largest. Accordingly, a first curvature between the first radius of curvature R1 and the second radius of curvature R2 can be smaller than a second curvature between the second radius of curvature R2 and the third radius of curvature R3. Where the curvatures of the various positions of the signal line CNL, corresponding to the various positions of the flexible region BDA, differ from one another, the load / stress may be concentrated on a specific section of the flexible region BDA. The load / stress may be a force acting on a unit area. For example, a specific region of the flexible region BDA on which the load / stress is concentrated may be a section of the flexible region BDA at a position closer to the forward region FA. The specific region on which the load / stress is concentrated may be a critical point S for crack occurrence, where the crack is more likely to occur in the signal line CNL than at other points.The critical point S for crack formation can be a position that defines the first radius of curvature R1, which has the smallest radius of curvature, and a first angular direction θ relative to the end (e.g., a side face) of the first plate 500. The first angle θ can be approximately 45 degrees. Accordingly, in another exemplary embodiment of the present disclosure, a configuration may be proposed which is able to prevent or suppress the critical point of crack occurrence due to the concentration of load / stress on the specific position of the bendable area BDA. Figures 6 and 7 are illustrations depicting a display device according to another exemplary embodiment of the present disclosure. In Figures 6 and 7, the same components as those in the exemplary embodiment of Figures 4 and 5 may use the same reference numerals. Accordingly, redundant descriptions may be omitted or briefly explained, and the differences between them are mainly described. For the sake of simplicity, Figures 6 and 7 show only the substrate 201 of the components of the display panel 200: the inorganic insulating structure MB, the connecting contact electrode LCT, the signal line CNL, the first planarization layer 251, the second planarization layer 252, and the organic insulating structure 266. In this respect, each of the second planarization layer 252 and the organic insulating structure 266 is made of an organic insulating material and is shown as a single layer. However, embodiments of the present disclosure are not limited to this. For example, each of the second planarization layer 252 and the organic insulating structure 266 can be composed of several layers. As shown in Figures 6 and 7, the substrate 201 of the display panel can have the front area FA, in which an image is displayed, the rear area BA, which is arranged to face a rear surface of the front area FA, and the flexible area BDA, which is arranged between the front area FA and the rear area BA. The flexible area BDA can extend from one side of the front area FA of the display panel and be bent downwards. When the flexible area BDA of the substrate 201 is bent, the printed circuit board 104 can be arranged on the rear area BA and facing away from the front area FA. The inorganic insulating structure MB can be arranged on a section of the non-display area NAA between the display area AA and the flexible area BDA of substrate 201. The connecting contact electrode LCT can be arranged on the inorganic insulating structure MB. The first planarization layer 251, which covers the connecting contact electrode LCT, can be arranged on the inorganic insulating structure MB. The first planarization layer 251 can extend from, onto, and along the front region FA and then over, onto, and along the flexible region BDA and along the rear region BA. The first planarization layer 251 can have different thicknesses at different positions, corresponding to different positions A, B, C, D, E, F, G, and H of the flexible area BDA. For example, the first planarization layer 251 can have different thicknesses at different positions corresponding to the first position A, the second position B, the third position C, the fourth position D, the fifth position E, the seventh position F, the eighth position G, and the ninth position H. For example, the first position A can be the starting point of the flexible area BDA, and the ninth position H can be the ending point. The second through eighth positions B through G can be positions within the flexible area BDA. After the bending operation of the bendable area BDA has been performed, the small-curvature bending operation (fixed bending operation) can further be performed on the substrate 201 to further reduce the edging area. The small-curvature bending operation (fixed bending operation) can be an operation of pulling the end of the second plate 510 in the horizontal direction F (see Fig. 4) such that the end of the second plate 510 is positioned a predetermined distance d further inward than the end of the first plate 500. Accordingly, the substrate 201 can be bent such that a section of the front area FA, visible to the observer, has a smaller radius of curvature and is thus reduced. An asymmetrical curvature can therefore be formed, and the greater load / stress can be concentrated on the section with the smaller radius of curvature.Accordingly, the load / stress can be concentrated on the section of the front region FA where the substrate 201 is bent to have the smaller radius of curvature. For example, the load / stress can be concentrated on a position corresponding to a position that defines the 45-degree angular direction relative to the end of the first plate 500. For example, the position that defines the 45-degree angular direction with respect to the end of the first plate 500 can be a position of the bendable region BDA that corresponds to a position between the first position A, which is closest to the front region FA, and the seventh position F. Accordingly, in a state where the substrate 201 is bent with asymmetric curvature, the first planarization layer 251 can be structured such that its thickness changes as it extends from the front region FA across the flexible region BDA to the rear region BA. With such varying thickness, the first planarization layer 251 can have an outer surface with a uniform radius of curvature as it extends from the front region FA across the flexible region BDA to the rear region BA. Thus, the radius of curvature of the signal line CNL, which is located on the first planarization layer 251, can be uniform along the entire length of the flexible region BDA.For example, the thickness of the first planarization layer 251 in a region between the first position A and the seventh position F, where the substrate 201 is bent to have a smaller radius of curvature, can be relatively smaller than that at the other positions F, G, and H. Additionally, the signal line CNL can conform to and extend along the profile of the first planarization layer 251. Then, as shown in Fig. 7, the first radius of curvature R1, the second radius of curvature R2, and the third radius of curvature R3 can be equal to each other. Accordingly, a first curvature between the first radius of curvature R1 and the second radius of curvature R2 and a second curvature between the second radius of curvature R2 and the third radius of curvature R3 can be equal to each other. However, the present disclosure is not limited to the example configurations in which the first radius of curvature R1, the second radius of curvature R2, and the third radius of curvature R3 are equal. For example, even if the first through third radii of curvature R1, R2, and R3 are not equal, the first planarization layer 251 can be structured such that its thickness changes in a manner conforming to the asymmetric curvature shape of the substrate 201. For example, the first planarization layer 251 can be structured such that where the substrate 201 has a smaller curvature, the thickness of the first planarization layer 251 can be smaller, thereby compensating for the curvature of the section of the substrate 201 with the smaller curvature. Additionally, substrate 201 can have a neutral plane NS, which is defined within it. The neutral plane NS refers to a plane in which compressive and tensile stresses counteract each other during a bending operation, so that the net stress is zero. As the position is closer to the neutral plane NS, the applied stress can decrease. Since the first planarization layer 251 is constructed to have different thicknesses at different positions, corresponding to different positions of the bendable area BDA, distances between the neutral plane NS of the substrate 201, which has the asymmetric curvature, and the outer surface of the first planarization layer 251 can differ at different positions corresponding to the different positions of the bendable area BDA. The signal line CNL can extend conformally along the profile of the outer surface of the first planarization layer 251, which has different thicknesses at different positions corresponding to different positions of the flexible area BDA. Accordingly, the distances between the neutral plane NS of the substrate 201, which has the asymmetric curvature, and the signal line CNL can differ at different positions corresponding to the different positions of the flexible area BDA. For example, the position of the flexible region BDA between the first position A, which is closest to the front region FA, and the seventh position F can be an area where the load / stress is / will be concentrated. Thus, the thickness of the first planarization layer 251 at a position corresponding to this position in the flexible region BDA can be less than the thickness at positions corresponding to positions other than those in the flexible region BDA from the first position A to the seventh position F. Accordingly, a section of the signal line CNL located on the section of the first planarization layer 251 corresponding to the area from the first position A to the seventh position F can be closer to the neutral plane NS. Accordingly, the section of the signal line CNL, which is located on the section of the first planarization layer 251 corresponding to the area from the first position A to the seventh position F, can be closer to the neutral plane NS, so that such potential damage, such as cracks, can be prevented or suppressed. This can prevent or suppress the concentration of stress / tension at the specific point in substrate 201, which has the asymmetric curvature, thereby preventing or suppressing a potential defect, such as a crack, in the signal line CNL. Therefore, the signal supplied to the display area AA can be transmitted more stably via the signal line CNL, thus reducing the defect rate of the display device. Consequently, the defect rate of the display device due to damage to the signal line can be reduced, and thus the energy required for the additional production of the display device can be reduced, thereby reducing greenhouse gas emissions. Fig. 8 is a view showing a bendable area according to another exemplary embodiment of the present disclosure. Fig. 8 represents a state in which the display device is not bent. In Fig. 8, the same components as those in the exemplary embodiment of Figs. 4 and 5 may use the same reference numerals. Accordingly, redundant descriptions may be omitted or briefly explained, and differences between them are mainly described. As shown in Fig. 8, the inorganic insulating structure MB can be arranged on a section of the non-display area NAA between the display area AA and the flexible area BDA of the substrate 201. The interconnecting contact electrode LCT can be arranged on the inorganic insulating structure MB. The interconnecting contact electrode LCT can be electrically connected to the leads that supply a signal or voltage to the plurality of pixels P of the display area AA via the interconnecting electrodes, each of which extends through the stack of multiple insulating layers that form the inorganic insulating structure MB. The first planarization layer 251, which covers the connecting contact electrode LCT, can be arranged on the inorganic insulating structure MB. The first planarization layer 251 can extend from, onto, and along the front region FA and then over, onto, and along the flexible region BDA and along the rear region BA. For example, the first planarization layer 251 can be arranged in the flexible region BDA such that it is in direct contact with the substrate 201. The first planarization layer 251 can be constructed to have different thicknesses (or heights) at different locations, corresponding to different positions in the bendable region BDA. The first planarization layer 251 can be structured by directing light of varying exposure levels onto different locations within it using a halftone masking process. The halftone mask can be, for example, a step-tablet mask or a multitone mask. For instance, a first region Z1, a second region Z2, a third region Z3, and a fourth region Z4 of the first planarization layer 251 can have different thicknesses. The first region Z1 of the first planarization layer 251 can be a position that corresponds to and vertically overlaps the front region FA.The second region Z2 can be an area designed to have a relatively small radius of curvature in the bendable region BDA during the small-curvature bending operation (fixed bending operation) following the main bending operation. For example, the second region Z2 can be an area where the load / stress is concentrated and can be located at the position that defines the angular direction of the first angle θ with respect to the end (or side face) of the first plate 500. The third region Z3 can be closer to the rear region BA than the second region Z2. The fourth region Z4 can be adjacent to the rear region BA. The thickness of the first planarization layer 251 can be smallest in the second region Z2, the area where the load / stress is concentrated, extending from the first to the fourth regions Z1, Z2, Z3, and Z4. For example, the thickness of the first planarization layer 251 can gradually increase as it extends from the second region Z2 to the first region Z1 and / or from the second region Z2 to the third region Z3. For example, the thickness of the first planarization layer 251 can be greatest in the fourth region Z4. The signal line CNL can be arranged on an upper surface of the first planarization layer 251. The signal line CNL can be electrically connected to the connecting contact electrode LCT by a connecting electrode that extends through a section of the first planarization layer 251 on the front region FA. The signal line CNL can extend from, onto, and along the front region FA and then over, onto, and along the flexible region BDA to and along the rear region BA. The signal line CNL can conform to and extend along a profile of the upper surface of the first planarization layer 251, which has different thicknesses at different locations corresponding to different positions in the bendable region BDA. Accordingly, the distances between the signal line CNL and the neutral plane NS can differ at different locations of the signal line CNL, corresponding to different positions in the bendable region BDA. A section of the signal line CNL located in a region where the load / stress is concentrated may be positioned closer to the neutral plane NS. For example, the thickness of the first planarization layer 251 may be smallest in the second region Z2, which is a region where the load / stress is concentrated.Additionally, the signal line CNL can be located at the smallest distance from the neutral plane NS on the section of the signal line CNL that is located on the second region Z2 of the first planarization layer 251. In other words, the section of the signal line CNL that is located on the second region Z2 of the first planarization layer 251 can be located closer to the neutral plane NS than the other sections of the signal line CNL that are located on the other regions Z1, Z3 and Z4 of the first planarization layer 251. The neutral plane NS refers to the plane where compressive and tensile stresses counteract each other during the bending process, and no load / stress is generated, or the net stress is zero. If the section of signal line CNL is located closer to the neutral plane NS, the mechanical stress applied to it decreases, thus potentially suppressing damage to the signal line CNL, such as a crack in the signal line. Accordingly, the signal line CNL, which is located on the first planarization layer 251 in the bendable area BDA, can be located closest to the neutral plane NS in the second area Z2 of the first planarization layer 251. Thus, even if the small-curvature bending operation (fixed bending operation) is / is carried out after the main bending operation, such potential damage, such as cracks, can be prevented or suppressed in this section of the signal line CNL. Additionally, the first planarization layer 251 can be structured such that the curvature of its outer surface (i.e., the upper surface on which the signal line CNL is located before the bending process) can vary in the bent state along the bendable area BDA in a manner consistent with the curvature of the substrate 201, which varies along the bendable area BDA. For example, the substrate 201 can have asymmetrical curvature in the bendable area BDA. In this respect, the signal line CNL can have the same radius of curvature throughout the entire bendable area BDA.Accordingly, it can be prevented or suppressed that the area of ​​the signal line CNL occurs on which the load / stress due to the asymmetric curvature of the substrate 201 can be concentrated, so that potential damage, such as cracks, can be prevented or suppressed in the signal line CNL. The second planarization layer 252 and the organic insulating structure 266 can be stacked vertically on the signal line CNL. The first adhesive element 305 and the polarizing layer 300 can be stacked vertically above the substrate 201 in the front region FA of the display panel. The protective layer 560 can be arranged on the outer surface of the display panel 200 in the flexible region BDA in the bent state. In a flat state, as shown in Fig. 8, the protective layer 560 can be arranged on a section of the organic insulating structure 266 on the flexible region BDA of the substrate 201. The protective layer 560 can extend from, along, and onto a portion of the front region FA and to, along, and onto a portion of the rear region BA. In the front region FA, the protective layer 560 can cover the side surface of the polarizing layer 300. In one example, the protective layer 560 can be thicker than the polarizing layer 300. Fig. 9 is a view showing a bendable area according to yet another exemplary embodiment of the present disclosure. Fig. 9 depicts a state in which the display device is not bent, that is, in the flat state. Figs. 10 and 11 are representations showing a load / stress during a bending operation. In Fig. 9, the same components as those of the exemplary embodiment in Fig. 8 may use the same reference numerals. Accordingly, redundant descriptions may be omitted or briefly explained, and differences between them are mainly described. As shown in Fig. 9, the inorganic insulating structure MB and the connecting contact electrode LCT can be arranged on the substrate 201. The first planarization layer 251, which covers the connecting contact electrode LCT, can be arranged on the inorganic insulating structure MB. The first planarization layer 251 can be constructed in a stepped structure, with steps resulting from its varying thicknesses at different positions along the bendable area BDA. For example, the first planarization layer 251 can have the first area Z1, the second area Z2, the third area Z3, and the fourth area Z4. The first area Z1 of the first planarization layer 251 can be a position that corresponds to and vertically overlaps the front area FA. The second area Z2 can be an area where the substrate 201 is intended to have the smallest radius of curvature in the bendable area BDA during the small-curvature bending operation (fixed bending operation) after the main bending operation.For example, the second region Z2 can be an area where the load / stress is / will be concentrated and can be located in a position that defines the angular direction of the first angle θ with respect to the end of the first plate 500 (see Fig. 4). The third region Z3 can be closer to the rear region BA than the second region Z2. The fourth region Z4 can be adjacent to the rear region BA. The thickness of the first planarization layer 251 can be smallest in the second region Z2, the area where the load / stress can be concentrated, extending from the first to the fourth regions Z1, Z2, Z3, and Z4. A first stepped structure, comprising multiple steps resulting from varying thicknesses, can be formed in a region extending from the second region Z2 towards the first region Z1. A second stepped structure, also comprising multiple steps resulting from varying thicknesses, can be formed in a region extending from the second region Z2 towards the third region Z3.In the first and second step structures, a step caused by the smallest thickness in the first step structure and a step caused by the smallest thickness in the second step structure can be integrally connected. The thickness of the first planarization layer 251 can be greatest in either the first region Z1 or the fourth region Z4. The first step structure of the first planarization layer 251, which exhibits the step structure, can comprise a first surface 251a extending in a first direction parallel to the upper surface of the substrate 201 (e.g., in the flat state), a second surface 251b extending in the first direction parallel to the upper surface of the substrate 201 and arranged at a higher or lower position than the first surface 251a, and a side surface 251c extending in a direction perpendicular to the upper surface of the substrate 201 and connecting the first surface 251a and the second surface 251b. For example, the steps of the first step structure can be composed of the first surface 251a, the second surface 251b, and the side surface 251c, which connects the first surface 251a and the second surface 251b, which are arranged in the first direction and connected to each other.For example, the first direction could be a direction from the second area Z2 to the first area Z1. The second stepped structure of the first planarization layer 251, which exhibits the stepped structure, can comprise a first surface 251a extending in a second direction parallel to the upper surface of the substrate 201 (e.g., in the flat state), a second surface 251b extending in a second direction parallel to the upper surface of the substrate 201 and arranged at a higher or lower position than the first surface 251a, and a side surface 251c extending in a direction perpendicular to the upper surface of the substrate 201 and connecting the first surface 251a and the second surface 251b. For example, the steps of the second stepped structure can be composed of the first surface 251a, the second surface 251b, and the side surface 251c, which connects the first surface 251a and the second surface 251b, which are arranged in the second direction and connected to each other.For example, the second direction could be a direction from the second area Z2 to the third area Z3. The stepwise structure of the first planarization layer 251 can be formed by shining light of different exposure amounts onto different positions of it in a halftone masking process. The signal line CNL can be arranged on the first planarization layer 251. The signal line CNL can extend conformally on and along a profile of the stepped upper surface of the first planarization layer 251, which has the step structure. For example, the signal line CNL can be arranged on the first surface 251a, the second surface 251b, and the side surface 251c of the first planarization layer 251. Accordingly, the signal line CNL can be designed to have a step structure that conforms to the step structure of the first planarization layer 251. The distances from the different positions of the signal line CNL, which has the step structure, to the neutral plane NS in the flexible region BDA can differ accordingly. For example, the thickness of the first planarization layer 251 can be smallest in the second region Z2, the area where the load / stress can be concentrated. Accordingly, the signal line CNL can be at its closest distance to the neutral plane NS on the section of the signal line CNL located on the second region Z2 of the first planarization layer 251. In other words, the section of the signal line CNL located on the second region Z2 of the first planarization layer 251 can be closer to the neutral plane NS than the other sections of the signal line CNL located on the other regions Z1, Z3, and Z4 of the first planarization layer 251. As shown in Fig. 10, when the bendable area BDA of the substrate 201 is bent during the bending process, the distance between the section of the signal line CNL located on the second area Z2 of the first planarization layer 251 and the neutral plane NS decreases, thus reducing the tensile stress exerted on the section of the signal line CNL. Consequently, potential damage, such as cracking, in the section of the signal line CNL located on the second area Z2 of the first planarization layer 251 can be prevented or suppressed. Additionally, the resistance to tensile stress can be improved due to the shape of the signal line CNL, which is designed in the stepped structure. For example, since the load / stress can be distributed over a stepped section extending between the first surface 251a and the side surface 251c, and between the side surface 251c and the second surface 251b of the stepped structure, the resistance to the tensile stress exerted on it during the bending process can be improved. For example, as shown in Fig. 11, in example case (a) of the signal line CNL constructed in a flat structure, the direction in which the stress is / becomes distributed is limited to the horizontal direction of the signal line CNL, as indicated by the arrow. Thus, the stress can be / become concentrated in the vertical direction, so that a crack CK can occur in the signal line CNL. However, in example case (b) of the signal line CNL constructed in the stepped structure, the stress can be / become distributed not only in the horizontal direction but also in the stepped structure, thereby preventing or suppressing the concentration of the stress. This can prevent or suppress potential cracks resulting from stress concentration. Fig. 12 is a view showing a bendable area according to yet another exemplary embodiment of the present disclosure. Fig. 12 depicts a state in which the display device is not bent, i.e., in the flat state. In Fig. 12, the same components as those of the exemplary embodiment in Fig. 9 can use the same reference numerals. Accordingly, redundant descriptions can be omitted or briefly explained, and differences between them are mainly described. As shown in Fig. 12, the inorganic insulating structure MB and the connecting contact electrode LCT can be arranged on the substrate 201. The first planarization layer 251, which covers the connecting contact electrode LCT, can be arranged on the inorganic insulating structure MB. The first planarization layer 251 can be arranged on the front area FA of the display panel. For example, the first planarization layer 251 can be arranged such that it is not on the flexible area BDA of the substrate 201. The substrate 201 can be designed to have different thicknesses at different locations, corresponding to different positions within the flexible area BDA. For example, the thickness of the substrate 201 within the flexible area BDA can refer to a thickness in the vertical direction from a bottom, rear, or back surface to a top or front surface of the substrate 201 (e.g., in the flat state). The substrate 201 can contain an organic insulating material containing polyimide (PI). Accordingly, a halftone mask can be placed on the substrate 201, and light can be directed onto the substrate such that light of varying intensity is directed to different positions of the substrate 201 within the flexible area BDA. The halftone mask can, for example, be a stepped-tablet mask or a multitone mask. The flexible region BDA of substrate 201 can be constructed in a stepped structure, in which steps caused by the varying thicknesses gradually change and are arranged sequentially as the substrate extends along the flexible region BDA. For example, the flexible region BDA of substrate 201 can have a first region Z1, a second region Z2, third regions Z3, and a fourth region Z4. The first region Z1 can be adjacent to the front region FA. The second region Z2 can be a region that has the smallest radius of curvature in the flexible region BDA in a small-curvature bending operation (fixed bending operation) after the main bending operation.For example, the second region Z2 can be an area where the load / stress is / will be concentrated and can be located in a position that defines the angular direction of the first angle θ with respect to the end of the first plate 500 (see Fig. 4). The third regions Z3 can each be on either side of the second region Z2 and can each be closer to the front region FA and the rear region BA than the second region Z2. The fourth region Z4 can be adjacent to the rear region BA. The thickness of substrate 201 can be smallest in the second region Z2, the area where the load / stress can be concentrated, from the first to the fourth regions Z1, Z2, Z3, and Z4. For example, the thickness of substrate 201 can gradually increase as substrate 210 extends from the second region Z2 through the third region Z3 to the first region Z1, or from the second region Z2 through the third region Z3 to the fourth region Z4. For example, the thickness of substrate 201 can be greatest in the first region Z1 or in the fourth region Z4. The signal line CNL can be arranged on the first planarization layer 251 on the front region FA. The signal line CNL can be electrically connected to the connecting contact electrode LCT via the connecting electrode that extends through the section of the first planarization layer 251 on the front region FA. The signal line CNL can extend from, onto, and along the front region FA and then over, onto, and along the flexible region BDA to and along the rear region BA. The signal line CNL can be arranged directly on the substrate 201 in the flexible region BDA. The signal line CNL can be in direct contact with the substrate 201 in the flexible region BDA. Accordingly, the signal line CNL can be constructed in a stepped structure that conforms to the stepped structure of the upper surface of the substrate 201 in the flexible region BDA. The distances between the different positions of the signal line CNL, constructed in the stepped structure, and the neutral plane in the bendable area BDA of the substrate 201 can vary. For example, the thickness of the substrate 201 may be smallest in the second area Z2, the area where the load / stress can be concentrated. Accordingly, the signal line CNL may be located at the closest distance to the neutral plane on the section of the signal line CNL that is situated on the second area Z2 of the substrate 201. This prevents or suppresses the concentration of the load / stress on it during the bending process, thereby preventing or suppressing potential cracks in the signal line CNL. This can prevent or protect the signal line CNL from being damaged. A display panel and a display device comprising the same, according to various aspects and embodiments of the present disclosure, can be described as follows. In one or more aspects of the present disclosure, a display panel has a front area comprising a display area and a non-display area outside the display area, a rear area below the front area, and a flexible area connected between the front area and the rear area, wherein the display panel is curved in the flexible area and comprises: an organic insulating layer arranged in the front area, the rear area, and the flexible area, which has a curvature in the flexible area; and a signal line on the organic insulating layer in the flexible area, wherein the organic insulating layer has a plurality of areas having different thicknesses in the flexible area. In accordance with some embodiments, the display panel may further comprise: a substrate in the front area, the rear area and the flexible area; and a first planarization layer over the substrate at least in the display area, wherein the organic insulating layer may be one of the substrate and the first planarization layer. In accordance with some embodiments, the display panel may further comprise a second planarization layer on top of the organic insulating layer and covering the signal line. In accordance with some embodiments, the substrate may have an asymmetric curvature in the bendable area, a first section of the substrate in the bendable area adjacent to the front area may have a first radius of curvature, a second section of the substrate in the bendable area may have a second radius of curvature, wherein the second section is arranged between the first section of the substrate and the rear area, a third section of the substrate in the bendable area may have a third radius of curvature, wherein the third section is arranged between the second section of the substrate and the rear area, and the first radius of curvature may be smaller than either the second radius of curvature or the third radius of curvature. In accordance with some embodiments, the organic insulating layer can be the first planarization layer. The first planarization layer can have a first region corresponding to the first section of the substrate, a second region corresponding to the second section of the substrate, and a third region corresponding to the third section of the substrate, of the plurality of regions. The first region of the first planarization layer can have a first thickness, the second region of the first planarization layer can have a second thickness, and the third region of the first planarization layer can have a third thickness. The second thickness can be less than at least one of the second and third thicknesses. The signal conductor can be arranged on an outer surface of the first planarization layer in the flexible region. In accordance with some embodiments, the substrate may have a neutral plane defined therein, and a distance between a section of the signal line located on the first region of the first planarization layer and the neutral plane of the substrate may be greater than a distance between a section of the signal line located on the second region of the first planarization layer and the neutral plane of the substrate. In accordance with some embodiments, the outer surface of the first planarization layer can have the same radius of curvature at the first region, the second region and the third region, and the signal line can have a uniform radius of curvature over the first region, the second region and the third region of the first planarization layer. In accordance with some embodiments, the organic insulating layer can be the first planarization layer, and the plurality of regions of the organic insulating layer can have a first, a second, and a third region of the first planarization layer, arranged sequentially between the front region and the rear region, with the second region being located between the first region and the third region. The substrate can have an asymmetric curvature in the bendable region, and an outer surface of the first planarization layer can have a stepped structure, comprising a plurality of steps arranged along the bendable region at varying distances from the substrate. In accordance with some embodiments, the stepped structure of the first planarization layer may comprise: a first stepped structure comprising interconnected steps of increasing height, arranged from the second region towards the first region adjacent to the front region, comprising a plurality of steps; and a second stepped structure comprising other steps of increasing height, arranged from the second region towards the third region, comprising a plurality of steps. A step in the second region may have the smallest height among the plurality of steps. In accordance with some embodiments, one of the multiple steps may have: a first surface extending in a first direction to the front region; a second surface extending in a second direction to the rear region and arranged on a different vertical level than the first surface; and a side surface connecting the first surface and the second surface. In accordance with some embodiments, the signal line can be arranged on and along the first surface, the second surface and the side surface. In accordance with some embodiments, the organic insulating layer can be the substrate, and the majority of regions of the organic insulating layer can have a first section, a second section and a third section of the substrate arranged in sequence between the front region and the rear region. In accordance with some embodiments, the display panel may further comprise a second planarization layer on the signal line in the flexible area. The first planarization layer may also be located above the substrate in the non-display area of ​​the front region and may not extend to the flexible area. The signal line may be located directly on the substrate in the flexible area. In accordance with some embodiments, the substrate can have an asymmetric curvature in the bendable region. The first section of the substrate in the bendable region can be adjacent to the front region and have a first radius of curvature. The second section of the substrate in the bendable region can have a second radius of curvature, with the second section being located between the first section of the substrate and the rear region. The third section of the substrate in the bendable region can have a third radius of curvature, with the third section being located between the second section of the substrate and the rear region. The first radius of curvature can be smaller than both the second and third radii of curvature.The first section of the substrate can have a first thickness, the second section of the substrate can have a second thickness, and the third section of the substrate can have a third thickness. The second thickness can be less than at least one of the first and third thicknesses. In accordance with some embodiments, the substrate may have a neutral plane defined therein, and a distance between a section of the signal line located on the first section of the substrate and the neutral plane of the substrate may be greater than a distance between a section of the signal line located on the second section of the substrate and the neutral plane of the substrate. In accordance with some embodiments, the signal line can extend from the front area, across the flexible area, to the rear area. In accordance with some embodiments, the display panel may further comprise: a substrate in the front area, the rear area and the flexible area; a first planarization layer on the substrate at least in the display area; a pixel driver circuit comprising at least one transistor on the substrate and under the first planarization layer in the display area; a light-emitting element on the pixel driver circuit; a pixel contact electrode electrically connecting the pixel driver circuit and the light-emitting element; and a touch sensor on the light-emitting element.The at least one transistor may have a semiconductor layer, a gate electrode overlapping the semiconductor layer, a gate insulating layer between the semiconductor layer and the gate electrode, and a source electrode and a drain electrode electrically connected in an associated manner to opposite sides of the semiconductor layer. In accordance with some embodiments, the display panel may further have a connecting contact electrode under the signal line in the front area and electrically connected to the signal line, wherein the connecting contact electrode may be of the same material as that contained in at least one of the source electrode and the drain electrode. In accordance with some embodiments, the signal line may be made of the same material as the pixel contact electrode. In one or more other aspects of the present disclosure, a display device comprises: the display panel according to one of the above exemplary embodiments of the present disclosure; a printed circuit board on the rear region of the display panel; a polarizing layer on the front region of the display panel; a cover element on the polarizing layer; and a protective layer on an outer surface of the display panel in the flexible region and extending to the front region and the rear region of the display panel.

Claims

Display panel (200) comprising a front area (FA) having a display area (AA) and a non-display area (NAA) outside the display area (AA), a rear area (BA) below the front area (FA), and a flexible area (BDA) connecting the front area (FA) and the rear area (BA), wherein the display panel (200) is curved in the flexible area (BDA) and comprises: an organic insulating layer arranged in the front area (FA), the rear area (BA), and the flexible area (BDA), which has a curvature in the flexible area (BDA); and a signal line (CNL) on the organic insulating layer in the flexible area (BDA), wherein the organic insulating layer has a plurality of areas having different thicknesses in the flexible area (BDA). Display panel (200) according to claim 1, which further comprises: a substrate (201) in the front area (FA), the rear area (BA) and the flexible area (BDA); and a first planarization layer (251) over the substrate (201) at least in the display area (AA), wherein the organic insulating layer is one of the substrate (201) and the first planarization layer (251). Display panel (200) according to claim 2, which further comprises: a second planarization layer (252) on the organic insulating layer and covering the signal line (CNL). Display panel (200) according to claim 2 or 3, wherein: the substrate (201) has an asymmetric curvature in the bendable area (BDA); a first section of the substrate (201) in the bendable area (BDA) adjacent to the front area (FA) has a first radius of curvature (R1); a second section of the substrate (201) in the bendable area (BDA) has a second radius of curvature (R2), wherein the second section is arranged between the first section of the substrate (201) and the rear area (BA); a third section of the substrate (201) in the bendable area (BDA) has a third radius of curvature (R3), wherein the third section is arranged between the second section of the substrate (201) and the rear area (BA); and the first radius of curvature (R1) is smaller than each of the second radius of curvature (R2) and the third radius of curvature (R3). Display panel (200) according to claim 4, wherein: the organic insulating layer is the first planarization layer (251); the first planarization layer (251) has a first region corresponding to the first section of the substrate (201), a second region corresponding to the second section of the substrate (201), and a third region corresponding to the third section of the substrate (201), of the plurality of regions; the first region of the first planarization layer (251) has a first thickness, the second region of the first planarization layer (251) has a second thickness, and the third region of the first planarization layer (251) has a third thickness; the second thickness is less than at least one of the first thickness and the third thickness; and the signal line (CNL) is arranged on an outer surface of the first planarization layer (251) in the bendable region (BDA). Display panel (200) according to claim 5, wherein: the substrate (201) has a neutral plane defined therein; and a distance between a section of the signal line (CNL) arranged on the first region of the first planarization layer (251) and the neutral plane of the substrate (201) is greater than a distance between a section of the signal line (CNL) arranged on the second region of the first planarization layer (251) and the neutral plane of the substrate (201). Display panel (200) according to claim 5 or 6, wherein: the outer surface of the first planarization layer (251) has the same radius of curvature at the first area, the second area and the third area; and the signal line (CNL) has a uniform radius of curvature over the first area, the second area and the third area of ​​the first planarization layer (251). Display panel (200) according to claim 2, wherein: the organic insulating layer is the first planarization layer (251); the plurality of regions (Z1, Z2, Z3, Z4) of the organic insulating layer comprise a first, a second and a third region (Z1, Z2, Z3) of the first planarization layer (251) arranged in sequence between the front region (FA) and the rear region (BA), wherein the second region (Z2) is located between the first region (Z1) and the third region (Z3); the substrate (201) has an asymmetric curvature in the flexible region (BDA); and an outer surface of the first planarization layer (251) has a stepped structure comprising a plurality of steps arranged along the flexible region (BDA) at different distances from the substrate (201). Display panel (200) according to claim 8, wherein the stepped structure of the first planarization layer (251) comprises: a first stepped structure comprising connected steps of increasing heights, arranged from the second area (Z2) towards the first area (Z1) adjacent to the front area (FA), of a plurality of steps; and a second stepped structure comprising other steps of increasing heights, arranged from the second area (Z2) towards the third area (Z3), of a plurality of steps; and wherein a step at the second area (Z2) has the smallest height of the plurality of steps. Display panel (200) according to claim 8 or 9, wherein one of the plurality of steps comprises: a first surface (251a) extending in a first direction to the front area (FA); a second surface (251b) extending in a second direction to the rear area (BA) and arranged on a different vertical level than the first surface (251a); and a side surface (251c) connecting the first surface (251a) and the second surface (251b). Display panel (200) according to claim 10, wherein the signal line (CNL) is arranged on and along the first surface (251a), the second surface (251b) and the side surface (251c). Display panel (200) according to claim 2, wherein: the organic insulating layer is the substrate (201); and the plurality of regions of the organic insulating layer comprise a first section, a second section and a third section of the substrate (201) arranged in sequence between the front region (FA) and the rear region (BA). Display panel (200) according to claim 12, which further comprises: a second planarization layer (252) on the signal line (CNL) in the flexible area (BDA), wherein the first planarization layer (251) is further arranged over the substrate (201) in the non-display area (NAA) of the front area (FA) and does not extend to the flexible area (BDA), and wherein the signal line (CNL) is directly on the substrate (201) in the flexible area (BDA). Display panel (200) according to claim 12 or 13, wherein: the substrate (201) has an asymmetric curvature in the bendable area (BDA); the first section of the substrate (201) in the bendable area (BDA) is adjacent to the front area (FA) and has a first radius of curvature (R1); the second section of the substrate (201) in the bendable area (BDA) has a second radius of curvature (R2), wherein the second section is arranged between the first section of the substrate (201) and the rear area (BA); the third section of the substrate (201) in the bendable area (BDA) has a third radius of curvature (R3), wherein the third section is arranged between the second section of the substrate (201) and the rear area (BA); the first radius of curvature (R1) is smaller than either of the second radius of curvature (R2) and the third radius of curvature (R3) is;the first section of the substrate (201) has a first thickness, the second section of the substrate (201) has a second thickness, and the third section of the substrate (201) has a third thickness; and the second thickness is less than at least one of the first thickness and the third thickness. Display panel (200) according to claim 14, wherein: the substrate (201) has a neutral plane defined therein; and a distance between a section of the signal line (CNL) arranged on the first section of the substrate (201) and the neutral plane of the substrate (201) is greater than a distance between a section of the signal line (CNL) arranged on the second section of the substrate (201) and the neutral plane of the substrate (201). Display panel (200) according to any one of claims 1 to 15, wherein the signal line (CNL) extends from the front area (FA) via the flexible area (BDA) to the rear area (BA). Display panel (200) according to claim 1, further comprising: a substrate (201) in the front region (FA), the rear region (BA) and the flexible region (BDA); a first planarization layer (251) on the substrate (201) at least in the display area (AA); a pixel control circuit (1100) comprising at least one transistor (220, 240) on the substrate (201) and under the first planarization layer (251) in the display area (AA); a light-emitting element (260) on the pixel control circuit (1100); a pixel contact electrode (255) electrically connecting the pixel control circuit (1100) and the light-emitting element (260);and a touch sensor (287) on the light-emitting element (260), wherein the at least one transistor (220, 240) has a semiconductor layer (221, 241), a gate electrode (223, 243) overlapping the semiconductor layer (221, 241), a gate insulating layer (222, 242) between the semiconductor layer (221, 241) and the gate electrode (223, 243), and a source electrode (224, 245) and a drain electrode (225, 246) electrically connected in an associated manner to opposite sides of the semiconductor layer (221, 241). Display panel (200) according to claim 17, which further comprises: a connecting contact electrode (LCT) under the signal line (CNL) in the front area (FA) and electrically connected to the signal line (CNL), wherein the connecting contact electrode (LCT) comprises the same material as that contained in at least one of the source electrode (224, 245) and the drain electrode (225, 246). Display panel (200) according to claim 17, wherein the signal line (CNL) has the same material as that contained in the pixel contact electrode (255). Display device (1) comprising: the display panel (200) according to any one of claims 1 to 19; a printed circuit board (104) on the rear area (BA) of the display panel (200); a polarizing layer (300) on the front area (FA) of the display panel (200); a cover element (400) on the polarizing layer (300); and a protective layer (560) on an outer surface of the display panel (200) in the flexible area (BDA) and extending to the front area (FA) and the rear area (BA) of the display panel (200).

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