Patent Publication Number: US-2022223805-A1

Title: Display panel and electronic apparatus

Description:
This application claims priority to Korean Patent Application No. 10-2021-0005394, filed on Jan. 14, 2021, and all the benefits accruing therefrom under 35 U.S.C. § 119, the content of which in its entirety is herein incorporated by reference. 
     BACKGROUND 
     1. Field 
     One or more embodiments relate to display panels and electronic apparatuses. 
     2. Description of the Related Art 
     An electronic apparatus with mobility has been widely used. In addition to a portable electronic apparatus such as a mobile phone, an electronic apparatus including a head-mounted display (“HMD”) worn on a head so that a user may experience augmented reality (“AR”) or virtual reality (“VR”) have been developed as a mobile electronic apparatus. 
     Such an electronic apparatus include a display panel to provide a user with various functions, for example, visual information such as images or videos. As other components for driving a display panel have been miniaturized, the proportion of the display panel in an electronic apparatus has gradually increased. 
     Also, flexible display panels that may be bent (or curved), folded, or rolled in a roll shape have been recently researched and developed. Furthermore, research and development has been actively conducted on a stretchable display panel that may change into various forms and a display panel that may curve at a corner and display an image. 
     SUMMARY 
     One or more embodiments include a display panel and an electronic apparatus capable of reducing a screen distortion. 
     Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments. 
     According to one or more embodiments, a display panel including a first edge extending in a first direction, a second edge extending in a second direction intersecting with the first direction, and a corner edge extending from the first edge to the second edge includes a substrate including a front area overlapping a center of the display panel and a corner area extending in a curved shape from the front area to the corner edge, and a pixel arranged over the substrate, where the display panel is curved in the corner area in a direction in which the corner edge approaches the center of the display panel. 
     In an embodiment, the display panel may include an upper surface where an image is displayed and a lower surface opposite to the upper surface, the corner area may include a plurality of corner areas, and the lower surface may at least partially surround the upper surface in the plurality of corner areas. 
     In an embodiment, the display panel may be flat in the front area. 
     In an embodiment, the display panel may be curved in a dome shape in the front area. 
     In an embodiment, the front area may include a first front area and a second front area arranged between the first front area and the corner area, and an upper surface of the display panel may be flat in the first front area and may be curved in the second front area with a different curvature from a curvature of the corner area. 
     In an embodiment, the corner area may include a first area and a second area spaced apart from each other, the pixel may include a first pixel arranged over the substrate to overlap the first area and a second pixel arranged over the substrate to overlap the second area, and the display panel may provide a through-portion at least partially defined by an edge of the first area and an edge of the second area. 
     In an embodiment, the first area and the second area may extend from the front area to the corner edge, and the edge of the first area and the edge of the second area may face each other. 
     In an embodiment, the corner area may further include a first extension area extending in a first extension direction and a second extension area extending in a second extension direction intersecting with the first extension direction, one of the first extension area and the second extension area may extend from the first area to the second area, and an edge of the one of the first extension area and the second extension area, the edge of the first area, and the edge of the second area may define at least a portion of the through-portion. 
     In an embodiment, the corner area may further include an extension area extending from the first area to the second area, an extension direction of the extension area may change at least two times along a way from the first area to the second area, and an edge of the extension area, the edge of the first area, and the edge of the second area may define at least a portion of the through-portion. 
     In an embodiment, the display panel may further include a first display element arranged over the substrate to overlap the first area and implement the first pixel, a second display element arranged over the substrate to overlap the second area and implement the second pixel, and an encapsulation layer covering the first display element and the second display element and including at least one inorganic encapsulation layer and at least one organic encapsulation layer, wherein the encapsulation layer may be separated with the through-portion therebetween. 
     According to one or more embodiments, an electronic apparatus includes a display panel including a first edge extending in a first direction, a second edge extending in a second direction intersecting with the first direction, and a corner edge extending from the first edge to the second edge, and an optical unit including a plurality of lenses facing the display panel, where a lens edge of each of the plurality of lenses extends while being spaced apart from the corner edge by a uniform interval in a plan view. 
     In an embodiment, each of the lens edge and the corner edge may have a curvature, and a curvature center of the lens edge and a curvature center of the corner edge may coincide with each other in the plan view. 
     In an embodiment, the lens edge may have a curved shape at least partially surrounding a central axis of the optical unit, and the corner edge may have a curved shape at least partially surrounding a center of the display panel. 
     In an embodiment, the display panel may include a substrate including a front area overlapping a center of the display panel and a corner area extending from the front area to the corner edge, and a pixel arranged over the substrate, wherein the display panel may be curved in the corner area in a direction in which the corner edge approaches the center of the display panel. 
     In an embodiment, the display panel may be curved in a direction toward the plurality of lenses. 
     In an embodiment, the corner area may include a plurality of corner areas, and the plurality of lenses may face the plurality of corner areas, respectively. 
     In an embodiment, each of the plurality of lenses may include a lower surface facing the display panel and an upper surface opposite to the lower surface, the upper surface may include a first upper surface and a second upper surface connected to the first upper surface and extending in a direction intersecting with the first upper surface, and the second upper surface may be connected to the lower surface and may extend in a direction intersecting with the lower surface. 
     In an embodiment, the first upper surface may include a flat surface, and the second upper surface may include a curved surface. 
     In an embodiment, the display panel may include a first display panel and a second display panel, the optical unit may include a first optical unit and a second optical unit, the first optical unit may face the first display panel, and the second optical unit may face the second display panel. 
     In an embodiment, the electronic apparatus may further include a case unit accommodating the display panel and the optical unit, and a fixing unit which fixes the case unit to a user&#39;s head. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of certain embodiments will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a perspective view schematically illustrating an electronic apparatus according to an embodiment; 
         FIG. 2  is an exploded view schematically illustrating an electronic apparatus according to an embodiment; 
         FIG. 3  is a plan view schematically illustrating a display panel according to an embodiment; 
         FIGS. 4A to 4D  are cross-sectional views schematically illustrating display panels according to various embodiments; 
         FIG. 5  is a perspective view schematically illustrating an optical unit according to an embodiment; 
         FIG. 6  is a schematic cross-sectional view of the optical unit taken along line VI-VI′ of  FIG. 5 ; 
         FIG. 7  is a plan view schematically illustrating a display panel and an optical unit according to an embodiment; 
         FIGS. 8A and 8B  are cross-sectional views schematically illustrating a display panel and an optical unit according to an embodiment; 
         FIG. 9A  illustrates an example of an image displayed on a display panel; 
         FIG. 9B  illustrates an example of an image recognized by a user through an optical unit after being displayed on a display panel according to a comparative example; 
         FIG. 10  is a plan view schematically illustrating a display panel according to an embodiment; 
         FIG. 11  is an equivalent circuit diagram schematically illustrating a pixel circuit applicable to a display panel and an organic light emitting diode connected to the pixel circuit; 
         FIG. 12  is a schematic cross-sectional view of a display panel taken along line XII-XII′ of  FIG. 10 , according to an embodiment; 
         FIG. 13  is a plan view schematically illustrating a corner area according to an embodiment; 
         FIGS. 14A and 14B  are plan views schematically illustrating a corner area according to an embodiment; and 
         FIG. 15  is a cross-sectional view schematically illustrating a display panel in a corner area according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Throughout the disclosure, the expression “at least one of a, b or c” indicates only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof. 
     The disclosure may include various embodiments and modifications, and certain embodiments thereof are illustrated in the drawings and will be described herein in detail. The effects and features of the disclosure and the accomplishing methods thereof will become apparent from the embodiments described below in detail with reference to the accompanying drawings. However, the disclosure is not limited to the embodiments described below and may be embodied in various modes. 
     Hereinafter, embodiments will be described in detail with reference to the accompanying drawings, and in the following description, like reference numerals will denote like elements and redundant descriptions thereof will be omitted for conciseness. 
     It will be understood that although terms such as “first” and “second” may be used herein to describe various elements, these elements should not be limited by these terms and these terms are only used to distinguish one element from another element. 
     As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     It will be understood that terms such as “comprise,” “include,” and “have” used herein specify the presence of stated features or components, but do not preclude the presence or addition of one or more other features or components. 
     It will be understood that when a layer, region, or element is referred to as being “on” another layer, region, or element, it may be “directly on” the other layer, region, or element or may be “indirectly on” the other layer, region, or element with one or more intervening layers, regions, or elements therebetween. 
     Sizes of elements in the drawings may be exaggerated for convenience of description. In other words, because the sizes and thicknesses of elements in the drawings are arbitrarily illustrated for convenience of description, the disclosure is not limited thereto. 
     When a certain embodiment may be implemented differently, a particular process order may be performed differently from the described order. For example, two consecutively described processes may be performed substantially at the same time or may be performed in an order opposite to the described order. 
     It will be understood that when a layer, region, or component is referred to as being “connected to” another layer, region, or component, it may be “directly connected to” the other layer, region, or component or may be “indirectly connected to” the other layer, region, or component with one or more intervening layers, regions, or components therebetween. For example, it will be understood that when a layer, region, or component is referred to as being “electrically connected to” another layer, region, or component, it may be “directly electrically connected to” the other layer, region, or component or may be “indirectly electrically connected to” the other layer, region, or component with one or more intervening layers, regions, or components therebetween. 
     An electronic apparatus may include a display panel. The display panel may display a moving image or a still image and may be used as a display screen of various products such as televisions, notebook computers, monitors, billboards, and Internet of Things (“IoT”) as well as portable electronic apparatuses such as mobile phones, smart phones, tablet personal computers (“PCs”), mobile communication terminals, electronic notebooks, electronic books, portable multimedia players (“PMPs”), navigation, and Ultra Mobile PCs (“UMPCs”). Also, the display panel according to an embodiment may be used in wearable devices such as smart watches, watch phones, glasses-type displays, and head-mounted displays (HMDs). Also, the display panel according to an embodiment may be used as a center information display (“CID”) located at a vehicle&#39;s instrument panel or a vehicle&#39;s center fascia or dashboard, a room mirror display replacing a vehicle&#39;s side mirror, or a display located at a rear side of a vehicle&#39;s front seat as an entertainment for a vehicle&#39;s rear seat. 
       FIG. 1  is a perspective view schematically illustrating an electronic apparatus  1  according to an embodiment.  FIG. 2  is an exploded view schematically illustrating an electronic apparatus  1  according to an embodiment. 
     Referring to  FIGS. 1 and 2 , the electronic apparatus  1  may be worn on the head of a user (not illustrated). The electronic apparatus  1  may provide an image in a state where the user&#39;s actual peripheral view is blocked or not blocked. The user wearing the electronic apparatus  1  may be easily immersed in augmented reality or virtual reality. The electronic apparatus  1  may include a display panel  10 , an optical unit  20 , a case unit  30 , a fixing unit  40 , and a cushion unit  50 . 
     The display panel  10  may provide an image. The display panel  10  may provide an image by emitting light. The display panel  10  may be accommodated in the case unit  30 . In an embodiment, the electronic apparatus  1  may include a plurality of display panels  10 . For example, the electronic apparatus  1  may include a first display panel  10 A and a second display panel  10 B. In this case, the first display panel  10 A and the second display panel  10 B may overlap a plurality of optical units  20  in the z direction. The z direction may be parallel to the central axis  10 AX of the display panel  10  and the central axis  20 AX of the optical units  20  (See  FIG. 8A ). The first display panel  10 A may be a left-eye display panel. The second display panel  10 B may be a right-eye display panel. In other embodiments, the electronic apparatus  1  may include one display panel  10 . In this case, each of the plurality of optical units  20  may overlap the one display panel  10 . 
     The display panel  10  may be curved (or bent). In an embodiment, the display panel  10  may include a first edge extending in a first direction, a second edge extending in a direction intersecting with the first direction, and a corner edge extending from the first edge to the second edge. In an embodiment, a first portion of the display panel  10  including the first edge may be curved. In an embodiment, a second portion of the display panel  10  including the second edge may be curved. In an embodiment, a corner portion of the display panel  10  including the corner edge may be curved. 
     The optical unit  20  may transmit the light emitted from the display panel  10 . The optical unit  20  may refract and/or reflect the light emitted from the display panel  10 . In an embodiment, the optical unit  20  may enlarge the image provided from the display panel  10 . The optical unit  20  may be arranged to face the display panel  10 . When the user wears the electronic apparatus  1 , the optical unit  20  may be arranged between the user and the display panel  10 . Thus, the user may perceive the light that is emitted from the display panel  10  and refracted and/or reflected by the optical unit  20 . In an embodiment, the optical unit  20  may include at least one of a lens and a mirror. 
     In an embodiment, the electronic apparatus  1  may include a plurality of optical units  20 . For example, the electronic apparatus  1  may include a first optical unit  20 A and a second optical unit  20 B. In this case, the first display panel  10 A may face the first optical unit  20 A. The second display panel  10 B may face the second optical unit  20 B. The first optical unit  20 A may be a left-eye optical unit for a left-eye. The second optical unit  20 B may be a right-eye optical unit for a right-eye. In other embodiments, the electronic apparatus  1  may include one optical unit  20 . 
     The case unit  30  may accommodate the display panel  10  and the optical unit  20 . The case unit  30  may have a space therein, and the display panel  10  and the optical unit  20  may be arranged in the space. The case unit  30  may protect the display panel  10  and the optical unit  20  from external impact. In an embodiment, the case unit  30  may be divided into a cover unit  31  and a body unit  33 . In other embodiments, the cover unit  31  and the body unit  33  may be integrally provided. In an embodiment, the cover unit  31  may be opaque. In another embodiment, the cover unit  31  may be transparent. 
     The case unit  30  may support the curved display panel  10 . For example, the display panel  10  may be fixed inside the case unit  30 . Also, the case unit  30  may support and maintain the shape of the curved display panel  10 . 
     The fixing unit  40  may fix the case unit  30  to the user&#39;s head. Thus, the electronic apparatus  1  may be worn on the user&#39;s head. In an embodiment, the length of the fixing unit  40  may be adjusted. For example, the length of the fixing unit  40  may be adjusted according to the user&#39;s head circumference. 
     The fixing unit  40  may adhere the electronic apparatus  1  to the user&#39;s head. In an embodiment, the fixing unit  40  may have elasticity.  FIG. 1  illustrates that the fixing unit  40  is a strap; however, in other embodiments, the fixing unit  40  may be of various types such as a helmet coupled to the case unit  30  or temples connected to the case unit  30 . The fixing unit  40  may be connected to the case unit  30 . In an embodiment, the fixing unit  40  may be detachably attached to the case unit  30 . 
     The cushion unit  50  may improve the user&#39;s wearing fitness. When the user wears the electronic apparatus  1 , the cushion unit  50  may be arranged between the user and the case unit  30 . In an embodiment, the cushion unit  50  may be attached to the case unit  30 . In an embodiment, the cushion unit  50  may be detached from the case unit  30 . In an embodiment, the cushion unit  50  may be omitted. 
     The cushion unit  50  may include a material that may be freely modified in shape. For example, the cushion unit  50  may include a polymer resin. For example, the cushion unit  50  may include at least one of polyurethane, polycarbonate, polypropylene, and polyethylene. In other embodiments, the cushion unit  50  may include a sponge obtained by foaming a rubber liquid, a urethane-based material, or an acryl-based material. 
     Hereinafter, the display panel  10  and the optical unit  20  will be described in detail. 
       FIG. 3  is a plan view schematically illustrating a display panel  10  according to an embodiment.  FIGS. 4A to 4D  are cross-sectional views schematically illustrating display panels  10  according to various embodiments.  FIG. 3  is a plan view illustrating a curved display panel  10 .  FIGS. 4A to 4D  are cross-sectional views of the display panel taken along line IV-IV′ of  FIG. 3 , respectively. 
     Referring to  FIG. 3 , the display panel  10  may include an edge. The edge may be an end portion of the display panel  10 . The edge may be defined as a side surface  10 SS of the display panel  10 . In an embodiment, the display panel  10  may include an upper surface  10 US, a lower surface  10 LS, and a side surface  10 SS. The upper surface  10 US of the display panel  10  may be opposite to the lower surface  10 LS of the display panel  10 . The side surface  10 SS of the display panel  10  may be connected to the upper surface  10 US of the display panel  10  and the lower surface  10 LS of the display panel  10 . The side surface  10 SS of the display panel  10  may intersect with the upper surface  10 US of the display panel  10  and the lower surface  10 LS of the display panel  10 . 
     In an embodiment, the display panel  10  may include a first edge Ed 1 , a second edge Ed 2 , a third edge Ed 3 , a fourth edge Ed 4 , and a corner edge CEd. In some embodiments, some of the first edge Ed 1 , the second edge Ed 2 , the third edge Ed 3 , and the fourth edge Ed 4  may be omitted. In some embodiments, the display panel  10  may further include a fifth edge or may further include more edges. Hereinafter, a detailed description will be mainly given of a case where the display panel  10  includes a first edge Ed 1 , a second edge Ed 2 , a third edge Ed 3 , a fourth edge Ed 4 , and a corner edge CEd. 
     The first edge Ed 1  and/or the third edge Ed 3  may extend in a first direction. The second edge Ed 2  and/or the fourth edge Ed 4  may extend in a second direction intersecting with the first direction. In an embodiment, the first direction and the second direction may be perpendicular to each other. For example, the first direction may be an x direction or a −x direction, and the second direction may be a y direction or a −y direction. In other embodiments, the first direction and the second direction may form an acute angle or an obtuse angle therebetween. Hereinafter, a detailed description will be mainly given of a case where the first direction (e.g., x direction or −x direction) and the second direction (e.g., y direction or −y direction) are perpendicular to each other. 
     The corner edge CEd may extend between the adjacent edges among the first to fourth edges. In an embodiment, the corner edge CEd may include a first corner edge CEd 1 , a second corner edge CEd 2 , a third corner edge CEd 3 , and a fourth corner edge CEd 4 . In some embodiments, some of the first corner edge CEd 1 , the second corner edge CEd 2 , the third corner edge CEd 3 , and the fourth corner edge CEd 4  may be omitted. In some embodiments, a fifth corner edge or more corner edges may be further included. Hereinafter, a detailed description will be mainly given of a case where the corner edge CEd includes a first corner edge CEd 1 , a second corner edge CEd 2 , a third corner edge CEd 3 , and a fourth corner edge CEd 4 . 
     The first corner edge CEd 1  may extend between the first edge Ed 1  and the second edge Ed 2 . That is, the first corner edge CEd 1  may extend from the first edge Ed 1  to the second edge Ed 2 . The second corner edge CEd 2  may extend between the second edge Ed 2  and the third edge Ed 3 . That is, the second corner edge CEd 2  may extend from the second edge Ed 2  to the third edge Ed 3 . The third corner edge CEd 3  may extend between the third edge Ed 3  and the fourth edge Ed 4 . That is, the third corner edge CEd 3  may extend from the third edge Ed 3  to the fourth edge Ed 4 . The fourth corner edge CEd 4  may extend between the fourth edge Ed 4  and the first edge Ed 1 . That is, the fourth corner edge CEd 4  may extend from the fourth edge Ed 4  to the first edge Ed 1 . 
     The corner edge CEd may have a curved shape. In an embodiment, the corner edge CEd may have a curved shape at least partially surrounding a center  10 C of the display panel  10 . In an embodiment, the shape of the corner edge CEd may be a convex shape in a direction from the center  10 C of the display panel  10  to the corner edge CEd. In an embodiment, the shape of the corner edge CEd may be a portion of a circular shape. In another embodiment, the shape of the corner edge CEd may be a portion of an elliptical shape. 
     In an embodiment, the corner edge CEd may have a curved shape at least partially surrounding a central axis  10 AX of the display panel  10 . The central axis  10 AX of the display panel  10  may overlap the center  10 C of the display panel  10 . The central axis  10 AX of the display panel  10  may extend in a third direction intersecting with the first direction (e.g., x direction or −x direction) and the second direction (e.g., y direction or −y direction). For example, the third direction may be a z direction or a −z direction. 
     The display panel  10  may include a substrate  100 . The substrate  100  may include a front area FA and a corner area CA. The front area FA and the corner area CA may be surrounded by the edge of the display panel  10 . The front area FA may overlap the center  10 C of the display panel  10  and/or the central axis  10 AX of the display panel  10 . The corner area CA may extend from the front area FA to the corner edge CEd. The corner area CA may be connected to the corner edge CEd. 
     The corner areas CA may be provided as a plurality of corner areas. In an embodiment, the corner area CA may include a first corner area CA 1 , a second corner area CA 2 , a third corner area CA 3 , and a fourth corner area CA 4 . The first corner area CA 1  may extend from the front area FA to the first corner edge CEd 1 . The first corner area CA 1  may be connected to the first corner edge CEd 1 . The second corner area CA 2  may extend from the front area FA to the second corner edge CEd 2 . The second corner area CA 2  may be connected to the second corner edge CEd 2 . The third corner area CA 3  may extend from the front area FA to the third corner edge CEd 3 . The third corner area CA 3  may be connected to the third corner edge CEd 3 . The fourth corner area CA 4  may extend from the front area FA to the fourth corner edge CEd 4 . The fourth corner area CA 4  may be connected to the fourth corner edge CEd 4 . 
     The display panel  10  may be curved in the corner area CA. In an embodiment, the display panel  10  may be curved in at least one of the first corner area CA 1 , the second corner area CA 2 , the third corner area CA 3 , and the fourth corner area CA 4 . For example, the display panel  10  may be curved in the first corner area CA 1 , the second corner area CA 2 , the third corner area CA 3 , and the fourth corner area CA 4 . 
     The display panel  10  may be curved in the corner area CA in a direction in which the corner edge CEd approaches the center  10 C of the display panel  10 . In other words, the display panel  10  may be curved in the corner area CA in a direction in which the corner edge CEd approaches the central axis  10 AX of the display panel  10 . Thus, the display panel  10  may be at least partially curved toward the center  10 C of the display panel  10  and/or the central axis  10 AX of the display panel  10 . This means that any line on the display panel  10  and which connects the center  10 C and any point on the corner area CA in a shortest way is curved so that the direction of the curve of the line approaches the central axis  10 AX. For example, a hemisphere structure meets this condition, but a cylindrical structure does not meet this condition. 
     In some embodiments, the display panel  10  may be curved in a direction in which the edge of the display panel  10  approaches the center  10 C of the display panel  10 . For example, the display panel  10  may be curved in a direction in which at least one of the first to fourth edges Ed 1  to Ed 4  approaches the center  10 C of the display panel  10 . 
     Pixels (not illustrated) may be arranged over the substrate  100 . The pixels may be arranged over the substrate  100  to overlap at least one of the corner area CA and the front area FA. The pixels may emit light. Thus, the display panel  10  may display an image. 
     Referring to  FIGS. 4A to 4D , the display panel  10  may display an image on the upper surface  10 US of the display panel  10 . In other embodiments, the display panel  10  may display an image on the lower surface  10 LS of the display panel  10 . In other embodiments, the display panel  10  may display an image on both the upper surface  10 US of the display panel  10  and the lower surface  10 LS of the display panel  10 . 
     In an embodiment, the lower surface  10 LS of the display panel  10  may be curved to at least partially surround the upper surface  10 US of the display panel  10 . In an embodiment, a curvature radius  10 LSR of the lower surface  10 LS of the display panel  10  may be greater than a curvature radius  10 USR of the upper surface  10 US of the display panel  10 . Although not illustrated, in other embodiments, the upper surface  10 US of the display panel  10  may be curved to at least partially surround the lower surface  10 LS of the display panel  10 . In an embodiment, the curvature radius  10 USR of the upper surface  10 US of the display panel  10  may be greater than the curvature radius  10 LSR of the lower surface  10 LS of the display panel  10 . Hereinafter, a detailed description will be mainly given of a case where the lower surface  10 LS of the display panel  10  is curved to at least partially surround the upper surface  10 US of the display panel  10 . 
     In an embodiment, a portion of the upper surface  10 US of the display panel  10  overlapping the first corner area CA 1  may at least partially face a portion of the upper surface  10 US of the display panel  10  overlapping the third corner area CA 3 . Although not illustrated, in an embodiment, a portion of the upper surface  10 US of the display panel  10  overlapping the second corner area CA 2  may at least partially face a portion of the upper surface  10 US of the display panel  10  overlapping the fourth corner area CA 4 . 
     In an embodiment, the display panel  10  may be symmetrically curved in the first corner area CA 1  and the third corner area CA 3  with respect to the central axis  10 AX of the display panel  10 . Although not illustrated, in an embodiment, the display panel  10  may be symmetrically curved in the second corner area CA 2  and the fourth corner area CA 4  with respect to the central axis  10 AX of the display panel  10 . 
     Referring to  FIG. 4A , the display panel  10  may be flat in the front area FA. In this case, each of the upper surface  10 US of the display panel  10  and the lower surface  10 LS of the display panel  10  may extend in one direction in the front area FA. 
     Referring to  FIG. 4B , the display panel  10  may be curved in a dome shape in the front area FA. The display panel  10  may be convex downward in the front area FA. In this case, in the front area FA, the lower surface  10 LS of the display panel  10  may at least partially surround the upper surface  10 US of the display panel  10 . The upper surface  10 US of the display panel  10  and/or the lower surface  10 LS of the display panel  10  may be arranged lowest in the central axis  10 AX of the display panel  10 . In an embodiment, the curvature of the upper surface  10 US of the display panel  10  in the front area FA may be less than the curvature of the upper surface  10 US of the display panel  10  in the first corner area CA 1  and/or the third corner area CA 3 . In an embodiment, the curvature radius of the upper surface  10 US of the display panel  10  in the front area FA may be greater than or equal to the curvature radius  10 USR of the upper surface  10 US of the display panel  10  in the first corner area CA 1  and/or the third corner area CA 3 . 
     Referring to  FIG. 4C , the front area FA may include a first front area FA 1  and a second front area FA 2 . In an embodiment, the first front area FA 1  may overlap the central axis  10 AX of the display panel  10 . The display panel  10  may be flat in the first front area FA 1 . For example, the upper surface  10 US of the display panel  10  may be flat in the first front area FA 1 . The upper surface  10 US of the display panel  10  may extend in one direction in the first front area FA 1 . 
     The second front area FA 2  may be arranged between the first front area FA 1  and the corner area. For example, the second front area FA 2  may be arranged between the first front area FA 1  and the first corner area CA 1 . The second front area FA 2  may be arranged between the first front area FA 1  and the third corner area CA 3 . The second front area FA 2  may be symmetrically arranged with respect to the central axis  10 AX of the display panel  10 . 
     The second front area FA 2  of the display panel  10  may be curved. The display panel  10  may be convex downward in the second front area FA 2 . In this case, in the second front area FA 2 , the lower surface  10 LS of the display panel  10  may at least partially surround the upper surface  10 US of the display panel  10 . 
     The curvature of the upper surface  10 US of the display panel  10  in the second front area FA 2  may be different from the curvature of the upper surface  10 US of the display panel  10  in the first corner area CA 1  and/or the third corner area CA 3 . In an embodiment, the curvature of the upper surface  10 US of the display panel  10  in the second front area FA 2  may be less than the curvature of the upper surface  10 US of the display panel  10  in the first corner area CA 1  and/or the third corner area CA 3 . 
     A curvature radius FAR 2  of the upper surface  10 US of the display panel  10  in the second front area FA 2  may be different from the curvature radius  10 USR of the upper surface  10 US of the display panel  10  in the first corner area CA 1  and/or the third corner area CA 3 . For example, the curvature radius FAR 2  of the upper surface  10 US of the display panel  10  may be greater than the curvature radius  10 USR of the upper surface  10 US of the display panel  10  in the first corner area CA 1  and/or the third corner area CA 3 . Thus, the display panel  10  may be curved with a different curvature radius in the second front area FA 2  than in the corner area. 
     Referring to  FIG. 4D , a cover window CW may be arranged over the display panel  10 . In an embodiment, the cover window CW may be arranged on the upper surface  10 US of the display panel  10 . The cover window CW may protect the display panel  10 . Also, the cover window CW may support the display panel  10  to maintain the shape thereof. 
     The cover window CW may be a flexible window. The cover window CW may protect the display panel  10  while being easily curved according to an external force without generating a crack or the like. The cover window CW may include glass, sapphire, or plastic. The cover window CW may include, for example, ultra-thin glass (“UTG”) or colorless polyimide (“CPI”). In an embodiment, the cover window CW may have a structure in which a flexible polymer layer is arranged on one surface of a glass substrate or may include only a polymer layer. 
     Although not illustrated, in some embodiments, the display panel  10  and the cover window CW may be attached to each other by a transparent adhesive member such as an optically clear adhesive (“OCA”) film. 
     In some embodiments, a support member for supporting the display panel  10  may be further arranged on the lower surface  10 LS of the display panel  10 . In some embodiments, when the support member is arranged, the cover window CW may be omitted. 
       FIG. 5  is a perspective view schematically illustrating an optical unit  20  according to an embodiment.  FIG. 6  is a schematic cross-sectional view of the optical unit  20  taken along line VI-VI′ of  FIG. 5 . 
     Referring to  FIGS. 5 and 6 , the optical unit  20  may include a lens L and a support unit SP. The optical unit  20  may include a plurality of lenses L. In an embodiment, the plurality of lenses L may be separated from each other. In other embodiments, the plurality of lenses L may be integrally provided. In this case, the plurality of lenses L may be lens portions of the integrally provided lens L. In an embodiment, the optical unit  20  may include a first lens L 1 , a second lens L 2 , a third lens L 3 , and a fourth lens L 4 . In some embodiments, some of the first lens L 1 , the second lens L 2 , the third lens L 3 , and the fourth lens L 4  may be omitted. In some embodiments, the optical unit  20  may further include a fifth lens or may include more lenses. Hereinafter, a detailed description will be mainly given of a case where the optical unit  20  includes a first lens L 1 , a second lens L 2 , a third lens L 3 , and a fourth lens L 4 . 
     The plurality of lenses L may be arranged adjacent to each other. For example, the first lens L 1  and the second lens L 2  may be arranged adjacent to each other. The second lens L 2  and the third lens L 3  may be arranged adjacent to each other. The third lens L 3  and the fourth lens L 4  may be arranged adjacent to each other. The fourth lens L 4  and the first lens L 1  may be arranged adjacent to each other. 
     The plurality of lenses L may be arranged surrounding a central axis  20 AX of the optical unit  20 . For example, the first lens L 1 , the second lens L 2 , the third lens L 3 , and the fourth lens L 4  may be arranged surrounding the central axis  20 AX of the optical unit  20 . In an embodiment, the first lens L 1  and the third lens L 3  may be symmetrically arranged with respect to the central axis  20 AX of the optical unit  20 . The second lens L 2  and the fourth lens L 4  may be symmetrically arranged with respect to the central axis  20 AX of the optical unit  20 . 
     The plurality of lenses L may include a lens edge LE. The lens edge LE may be an end portion of the lenses L in a plan view (see  FIG. 7  described below). The lens edge LE may be an end portion of the lenses L in the plan view. For example, the first lens L 1  may include a first lens edge LE 1 . The second lens L 2  may include a second lens edge LE 2 . The third lens L 3  may include a third lens edge LE 3 . The fourth lens L 4  may include a fourth lens edge LE 4 . 
     The lens edge LE may have a curved shape at least partially surrounding the central axis  20 AX of the optical unit  20  in the plan view. The central axis  20 AX of the optical unit  20  may extend in the third direction (e.g., z direction or −z direction). In an embodiment, the lens edge LE may have a convex shape in a direction from the central axis  20 AX of the optical unit  20  to the lens edge LE. In an embodiment, the shape of the lens edge LE may be a portion of a circular shape. In another embodiment, the shape of the lens edge LE may be a portion of an elliptical shape. 
     Any one of the plurality of lenses L may include a lower surface LS, an upper surface US, and a side surface SS. The lower surface LS may be opposite to the upper surface US. That is, the lens L may include an upper surface US, a lower surface LS, and a side surface SS. 
     The upper surface US of the lens L may include a first upper surface US 1  and a second upper surface US 2 . The first upper surface US 1  may be flat. The second upper surface US 2  may be a curved surface. The second upper surface US 2  may include a curved edge to at least partially surround the first upper surface US 1 . 
     The first upper surface US 1  may be connected to the second upper surface US 2 . The first upper surface US 1  and the second upper surface US 2  may be connected to at a first point LP 1 . The first upper surface US 1  may intersect with the second upper surface US 2 . In an embodiment, the first upper surface US 1  and the second upper surface US 2  may be perpendicular to each other. In other embodiments, the first upper surface US 1  and the second upper surface US 2  may form an acute angle or an obtuse angle therebetween. 
     The first upper surface US 1  may be connected to the side surface SS. The first upper surface US 1  and the side surface SS may be connected to at a second point LP 2 . The first upper surface US 1  may intersect with the side surface SS. 
     The first upper surface US 1  may be inclined with respect to the central axis  20 AX of the optical unit  20 . The first upper surface US 1  may extend in a direction intersecting with the central axis  20 AX of the optical unit  20 . In an embodiment, the first upper surface US 1  may be inclined such that a first distance d 1  from the central axis  20 AX of the optical unit  20  to the first point LP 1  may be less than a second distance d 2  from the central axis  20 AX of the optical unit  20  to the second point LP 2 . 
     The second upper surface US 2  may be connected to the first upper surface US 1  at the first point LP 1 . The second upper surface US 2  may be connected to the lower surface LS at a third point LP 3 . The second upper surface US 2  may intersect with the lower surface LS. 
     The second upper surface US 2  may be inclined with respect to the central axis  20 AX of the optical unit  20 . The second upper surface US 2  may extend in a direction intersecting with the central axis  20 AX of the optical unit  20 . In an embodiment, the second upper surface US 2  may be inclined such that the first distance d 1  from the central axis  20 AX of the optical unit  20  to the first point LP 1  may be greater than a third distance d 3  from the central axis  20 AX of the optical unit  20  to the third point LP 3 . 
     The lower surface LS may be connected to the second upper surface US 2  at the third point LP 3 . The lower surface LS may be connected to the side surface SS. The lower surface LS may be connected to the side surface SS at a fourth point LP 4 . The lower surface LS may intersect with the side surface SS. In an embodiment, the lower surface LS may be bent. In other embodiments, the lower surface LS may have a curved surface. 
     The lower surface LS may be inclined with respect to the central axis  20 AX of the optical unit  20 . In an embodiment, the lower surface LS may be inclined such that the third distance d 3  from the central axis  20 AX of the optical unit  20  to the third point LP 3  may be less than a fourth distance d 4  from the central axis  20 AX of the optical unit  20  to the fourth point LP 4 . 
     The lens L may include the upper surface US, the lower surface LS, and the side surface SS as above to refract and/or reflect the light passing through the lens L. 
     The support unit SP may maintain the shape of the optical unit  20 . The support unit SP may support the plurality of lenses L. The support unit SP may support the first lens L 1 , the second lens L 2 , the third lens L 3 , and the fourth lens L 4 . 
     In an embodiment, the support unit SP may be provided as a plurality of support units. In an embodiment, the support unit SP may be arranged between the adjacent lenses L. For example, the support unit SP may be arranged between the first lens L 1  and the second lens L 2 . The support unit SP may be arranged between the second lens L 2  and the third lens L 3 . The support unit SP may be arranged between the third lens L 3  and the fourth lens L 4 . The support unit SP may be arranged between the fourth lens L 4  and the first lens L 1 . 
       FIG. 7  is a plan view schematically illustrating a display panel  10  and an optical unit  20  according to an embodiment.  FIGS. 8A and 8B  are cross-sectional views schematically illustrating a display panel  10  and an optical unit  20  according to an embodiment.  FIGS. 8A and 8B  are schematic cross-sectional views of the display panel  10  and the optical unit  20  taken along line VIII-VIII′ of  FIG. 7 . In  FIGS. 7, 8A, and 8B , like reference numerals as those in  FIGS. 3, 5, and 6  denote like members, and thus, redundant descriptions thereof will be omitted for conciseness. 
     Referring to  FIG. 7 , an electronic apparatus may include a display panel  10  and an optical unit  20 . The display panel  10  may include a first edge Ed 1  extending in a first direction (e.g., x direction or −x direction), a second edge Ed 2  extending in a second direction (e.g., y direction or −y direction), and a corner edge CEd 1  extending from the first edge Ed 1  to the second edge Ed 2 . 
     The display panel  10  may include a substrate  100  and a pixel (not illustrated). The substrate  100  may include a front area FA and a corner area CA. The front area FA may overlap a center  10 C of the display panel  10 . The corner area CA may extend from the front area FA to the corner edge CEd. The pixel may be arranged over the substrate  100  to overlap the corner area CA. The pixel may be arranged over the substrate  100  to overlap the front area FA. 
     The display panel  10  may be curved in the corner area CA. In an embodiment, the display panel  10  may be curved in at least one of the first corner area CA 1 , the second corner area CA 2 , the third corner area CA 3 , and the fourth corner area CA 4 . 
     The display panel  10  may be curved in the corner area CA in a direction in which the corner edge CEd approaches the center  10 C of the display panel  10 . In an embodiment, the display panel  10  may be curved in the corner area CA in a direction in which the corner edge CEd approaches the central axis  10 AX of the display panel  10 . Thus, the display panel  10  may be at least partially curved toward the center  10 C of the display panel  10  and/or the central axis  10 AX of the display panel  10 . 
     The optical unit  20  may include a plurality of lenses L. The plurality of lenses L may face the display panel  10 . For example, the first lens L 1 , the second lens L 2 , the third lens L 3 , and the fourth lens L 4  may face the display panel  10 . 
     The plurality of lenses L may include a lens edge LE. The lens edge LE may be an end portion of the lenses L in the plan view. The lens edge LE may be an end portion of the lenses L in the plan view which is a view in a third direction (e.g., z direction or −z direction). 
     In an embodiment, the center  10 C of the display panel  10  may overlap a central axis  20 AX of the optical unit  20 . The central axis  10 AX of the display panel  10  may coincide with the central axis  20 AX of the optical unit  20 . The front area FA of the display panel  10  may overlap the optical unit  20  in the plan view. 
     The plurality of lenses L may face a plurality of corner areas CA, respectively. For example, the first lens L 1  may face the first corner area CA 1 . The light emitted from the pixel arranged in the first corner area CA 1  may pass through the first lens L 1 . The second lens L 2  may face the second corner area CA 2 . The light emitted from the pixel arranged in the second corner area CA 2  may pass through the second lens L 2 . The third lens L 3  may face the third corner area CA 3 . The light emitted from the pixel arranged in the third corner area CA 3  may pass through the third lens L 3 . The fourth lens L 4  may face the fourth corner area CA 4 . The light emitted from the pixel arranged in the fourth corner area CA 4  may pass through the fourth lens L 4 . 
     In the plan view, the lens edge LE of any one of the plurality of lenses L may extend while being spaced apart from the corner edge CEd by a uniform interval Int. The corner edge CEd may extend while being spaced apart from the lens edge LE by a uniform interval Int. In other words, the corner edge CEd may extend corresponding to the lens edge LE. The corner edge CEd may extend along the lens edge LE. Thus, the corner edge CEd and the lens edge LE may have similar shapes. 
     In an embodiment, the corner edge CEd may have a curved shape and/or a curved surface shape at least partially surrounding the center  10 C of the display panel  10  and/or the central axis  10 AX of the display panel  10 . The corner edge CEd may have a curvature. In an embodiment, the corner edge CEd may have a corner curvature radius CER from a curvature center CCC of the corner edge CEd. 
     In an embodiment, the lens edge LE may have a curved shape at least partially surrounding the central axis  20 AX of the optical unit  20 . The lens edge LE may have a curvature. In an embodiment, the lens edge LE may have a lens curvature radius LR from a curvature center LCC of the lens edge LE. 
     In an embodiment, the curvature center LCC of the lens edge LE may coincide with the curvature center CCC of the corner edge CEd. The curvature center LCC of the lens edge LE may substantially coincide with the curvature center CCC of the corner edge CEd in the plan view. Thus, the lens edge LE may extend while being spaced apart from the corner edge CEd by a uniform interval Int, and the corner edge CEd and the lens edge LE may have shapes with a proportional relationship. 
     Referring to  FIGS. 8A and 8B , the display panel  10  may be curved in a direction toward the plurality of lenses L. For example, the lower surface  10 LS of the display panel  10  may be curved to at least partially surround the upper surface  10 US of the display panel  10 . In an embodiment, a curvature radius  10 LSR of the lower surface  10 LS of the display panel  10  may be greater than a curvature radius  10 USR of the upper surface  10 US of the display panel  10 . Although not illustrated, in other embodiments, the display panel  10  may be curved in a direction away from the plurality of lenses L. For example, the upper surface  10 US of the display panel  10  may be curved to at least partially surround the lower surface  10 LS of the display panel  10 . The curvature radius  10 USR of the upper surface  10 US of the display panel  10  may be greater than the curvature radius  10 LSR of the lower surface  10 LS of the display panel  10 . 
     Referring to  FIG. 8A , the display panel  10  may be flat in the front area FA. In this case, each of the upper surface  10 US of the display panel  10  and the lower surface  10 LS of the display panel  10  may extend in one direction in the front area FA. 
     Referring to  FIG. 8B , the display panel  10  may be curved in a dome shape in the front area FA. The display panel  10  may be convex downward in the front area FA.  FIG. 8B  illustrates a case where the curvature of the upper surface  10 US of the display panel  10  in the front area FA is equal to the curvature of the upper surface  10 US of the display panel  10  in the first corner area CA 1  and/or the third corner area CA 3 . 
     In an embodiment, the display panel  10  may be curved in the corner area CA to reduce a screen distortion viewed by the user. When the display panel  10  is generally flat, the user may view a screen distortion in the corner area CA of the display panel  10  due to the focal distance between the lens L and the display panel  10 . According to the embodiment, because the display panel  10  is suitably curved in the corner area CA, the screen distortion may be prevented or reduced. 
     In an embodiment, the lens L may include a lower surface LS, an upper surface US, and a side surface SS. In this case, light emitted from the display panel  10  may be incident on the lower surface LS. In this case, the light may be refracted at the lower surface LS. Next, the light may pass through the inside of the lens L and may be reflected at the first upper surface US 1 . In an embodiment, the light may be totally reflected at the first upper surface US 1 . Next, the light may again pass through the inside of the lens L and may be reflected at the lower surface LS. In an embodiment, the light may be totally reflected at the lower surface LS. Next, the light may be emitted through the second upper surface US 2 . The light may be refracted at the second upper surface US 2 . Next, the light may be incident on a user&#39;s eye EYE. Thus, the user may perceive the light emitted from the display panel  10 . 
     When the lens L described above is used, a total track length TTL from the upper surface  10 US of the display panel  10  to the user&#39;s eye EYE may be reduced. The total track length TTL from the upper surface  10 US of the display panel  10  to the user&#39;s eye EYE may be defined as the distance from the upper surface  10 US of the display panel  10  to the user&#39;s eye EYE in the direction of the central axis  10 AX of the display panel  10 . In an embodiment, the total track length TTL may be about 30 millimeters (mm) or less. Thus, the thickness of the electronic apparatus may be reduced. 
     In an embodiment, the corner edge CEd may have a curved shape at least partially surrounding the center  10 C of the display panel  10  and/or the central axis  10 AX of the display panel  10 . Also, in the plan view, the lens edge LE of any one of the plurality of lenses L may extend while being spaced apart from the corner edge CEd by a uniform interval Int. Thus, a portion of the display panel  10  in which a relatively large amount of distortion occurs may be removed, and the display panel  10  and the optical unit  20  arranged in the electronic apparatus  1  may be efficiently utilized. For example, the space utilization inside the case unit  30  of the electronic apparatus  1  may increase. 
       FIG. 9A  illustrates an example of an image displayed on a display panel.  FIG. 9B  illustrates an example of an image recognized by a user through an optical unit after being displayed on a display panel according to a comparative example. The display panel according to a comparative example may be a generally flat display panel. 
     Referring to  FIGS. 9A and 9B , the user may recognize an image displayed on the generally flat display panel, through the optical unit. In this case, as illustrated in  FIG. 9B , the user may perceive a screen distortion. For example, the screen distortion may increase in a diagonal direction away from the center of  FIG. 9A . For example, images  10 ,  15 ,  50 , and  55  may be distorted more severely than images  19 ,  22 ,  43 , and  46 . This may be because the optical unit including the plurality of lenses L described with reference to  FIGS. 8A and 8B  is used to reduce the total track length TTL from the upper surface  10 US of the display panel  10  to the user&#39;s eye EYE. 
     The display panel according to an embodiment may be curved in the corner area in a direction in which the corner edge approaches the center of the display panel. Particularly, the display panel  10  may be curved in at least one of the first corner area CA 1 , the second corner area CA 2 , the third corner area CA 3 , and the fourth corner area CA 4 . Also, the plurality of lenses L may face the plurality of corner areas CA, respectively. Thus, the screen distortion viewed by the user may be reduced. According to an embodiment, the total track length TTL from the upper surface  10 US of the display panel  10  to the user&#39;s eye EYE may be reduced while reducing the screen distortion viewed by the user. Thus, the thickness of the electronic apparatus  1  may be effectively reduced. 
       FIG. 10  is a plan view schematically illustrating a display panel  10  according to an embodiment.  FIG. 10  is a plan view schematically illustrating an unbent shape of the display panel  10  as a shape of the display panel  10  before the corner area CA is curved. 
     Referring to  FIG. 10 , the display panel  10  may include an edge. The edge may be an end portion of the display panel  10 . In an embodiment, the display panel  10  may include a first edge Ed 1 , a second edge Ed 2 , a third edge Ed 3 , a fourth edge Ed 4 , and a corner edge CEd. The first edge Ed 1  and/or the third edge Ed 3  may extend in a first direction. The second edge Ed 2  and/or the fourth edge Ed 4  may extend in a second direction intersecting with the first direction. 
     The corner edge CEd may extend between the adjacent edges. The corner edge CEd may have a curved shape at least partially surrounding a center  10 C of the display panel  10 . In an embodiment, the corner edge CEd may include a first corner edge CEd 1 , a second corner edge CEd 2 , a third corner edge CEd 3 , and a fourth corner edge CEd 4 . 
     The display panel  10  may include a substrate  100 . The substrate  100  may include a front area FA and a corner area CA. The corner area CA may extend from the front area FA to the corner edge CEd. The corner area CA may include the corner edge CEd. 
     The corner areas CA may be provided as a plurality of corner areas. In an embodiment, the corner area CA may include a first corner area CA 1 , a second corner area CA 2 , a third corner area CA 3 , and a fourth corner area CA 4 . 
     A pixel PX may be arranged over the substrate  100 . In an embodiment, the pixel PX may be arranged over the substrate  100  to overlap the corner area CA. In an embodiment, the pixel PX may be arranged over the substrate  100  to overlap the front area FA. 
     In an embodiment, the pixel PX may be connected to a scan line SL extending in the first direction (e.g., x direction or −x direction). In an embodiment, the pixel PX may be connected to a data line DL extending in the second direction (e.g., y direction or −y direction). 
     The display panel  10  may include a plurality of pixels PX, and the display panel  10  may display an image by using the plurality of pixels PX. Each of the pixels PX may include subpixels, and the subpixels may emit light of a certain color by using a display element. In the specification, the subpixel may refer to an emission area as a minimum unit for implementing an image. 
     Each of the plurality of pixels PX may include a display element. The display panel  10  may be an organic light emitting display panel using an organic light emitting diode including an organic emission layer. Alternatively, the display panel  10  may be a light emitting diode display panel using a light emitting diode LED. The size of the light emitting diode LED may be a micro scale or a nano scale. For example, the light emitting diode may be a micro light emitting diode. Alternatively, the light emitting diode may be a nanorod light emitting diode. The nanorod light emitting diode may include gallium nitride (GaN). In an embodiment, a color conversion layer may be arranged over the nanorod light emitting diode. The color conversion layer may include quantum dots. Alternatively, the display panel  10  may be a quantum dot light emitting display panel using a quantum dot light emitting diode including a quantum dot emission layer. Alternatively, the display panel  10  may be an inorganic light emitting display panel using an inorganic light emitting diode including an inorganic semiconductor. Hereinafter, a detailed description will be mainly given of a case where the display panel  10  is an organic light emitting display panel using an organic light emitting diode as a display element. 
       FIG. 11  is an equivalent circuit diagram schematically illustrating a pixel circuit PC applicable to a display panel and an organic light emitting diode OLED connected to the pixel circuit PC. 
     Referring to  FIG. 11 , the pixel circuit PC may be connected to a display element, for example, an organic light emitting diode OLED. In an embodiment, the pixel circuit PC and the organic light emitting diode OLED may implement a pixel PX. The pixel PX may include a pixel circuit PC and an organic light emitting diode OLED. 
     The pixel circuit PC may include a driving thin film transistor T 1 , a switching thin film transistor T 2 , and a storage capacitor Cst. Also, the organic light emitting diode OLED may emit red, green, or blue light or may emit red, green, blue, or white light. 
     The switching thin film transistor T 2  may be connected to a scan line SL and a data line DL and may be configured to transmit a data voltage or a data signal input from the data line DL to the driving thin film transistor T 1  according to a switching voltage or a scan signal input from the scan line SL. The storage capacitor Cst may be connected to the switching thin film transistor T 2  and a driving voltage line PL and may store a voltage corresponding to the difference between a voltage received from the switching thin film transistor T 2  and a first power voltage ELVDD supplied to the driving voltage line PL. 
     The driving thin film transistor T 1  may be connected to the driving voltage line PL and the storage capacitor Cst and may control a driving current flowing from the driving voltage line PL through the organic light emitting diode OLED in response to a voltage value stored in the storage capacitor Cst. The organic light emitting diode OLED may emit light with a certain brightness according to the driving current. An opposite electrode of the organic light emitting diode OLED may be supplied with a second power voltage ELVSS. 
     Although  FIG. 11  illustrates that the pixel circuit PC includes two thin film transistors and one storage capacitor, the pixel circuit PC may include three, four, five, or more thin film transistors. 
       FIG. 12  is a schematic cross-sectional view of a display panel  10  taken along line XII-XII′ of  FIG. 10 , according to an embodiment. 
     Referring to  FIG. 12 , the display panel  10  may include a substrate  100 , a buffer layer  111 , a pixel circuit layer PCL, a display element layer DEL, and an encapsulation layer ENL. 
     In an embodiment, the substrate  100  may include a first base layer  100   a , a first barrier layer  100   b , a second base layer  100   c , and a second barrier layer  100   d . In an embodiment, the first base layer  100   a , the first barrier layer  100   b , the second base layer  100   c , and the second barrier layer  100   d  may be sequentially stacked in the substrate  100 . In other embodiments, the substrate  100  may include glass. 
     At least one of the first base layer  100   a  and the second base layer  100   c  may include a polymer resin such as polyethersulfone, polyarylate, polyetherimide, polyethylene naphthalate, polyethylene terephthalate, polyphenylene sulfide, polyimide, polycarbonate, cellulose triacetate, or cellulose acetate propionate. 
     The first barrier layer  100   b  and the second barrier layer  100   d  may be barrier layers for preventing penetration of external foreign substances and may include a single layer or multiple layers including an inorganic material such as silicon nitride (SiN x ), silicon oxide (SiO 2 ), and/or silicon oxynitride (SiON). 
     The buffer layer  111  may be arranged over the substrate  100 . The buffer layer  111  may include an inorganic insulating material such as silicon nitride (SiN x ), silicon oxynitride (SiON), and silicon oxide (SiO 2 ) and may be a single layer or multiple layers including the inorganic insulating material. 
     The pixel circuit layer PCL may be arranged over the buffer layer  111 . The pixel circuit layer PCL may include a pixel circuit PC. The pixel circuit PC may include a driving thin film transistor T 1 , a switching thin film transistor T 2 , and a storage capacitor Cst. 
     The pixel circuit layer PCL may include an inorganic insulating layer IIL, a first organic insulating layer  115 , and a second organic insulating layer  116  arranged under and/or over the components of the driving thin film transistor T 1 . The inorganic insulating layer IIL may include a first gate insulating layer  112 , a second gate insulating layer  113 , and an interlayer insulating layer  114 . The driving thin film transistor T 1  may include a first semiconductor layer ACT 1 , a first gate electrode GE 1 , a first source electrode SE 1 , and a first drain electrode DE 1 . 
     The first semiconductor layer ACT 1  may include polysilicon. Alternatively, the first semiconductor layer ACT 1  may include amorphous silicon, may include an oxide semiconductor, or may include an organic semiconductor or the like. The first semiconductor layer ACT 1  may include a channel area and a drain area and a source area arranged on opposite sides of the channel area, respectively. 
     The first gate electrode GE 1  may overlap the channel area. The first gate electrode GE 1  may include a low-resistance metal material. The first gate electrode GE 1  may include a conductive material including molybdenum (Mo), aluminum (Al), copper (Cu), titanium (Ti), or the like and may include a single layer or multiple layers including the above material. 
     The first gate insulating layer  112  between the first semiconductor layer ACT 1  and the first gate electrode GE 1  may include an inorganic insulating material such as silicon oxide (SiO 2 ), silicon nitride (SiN x ), silicon oxynitride (SiON), aluminum oxide (Al 2 O 3 ), titanium oxide (TiO 2 ), tantalum oxide (Ta 2 O 5 ), hafnium oxide (HfO 2 ), and/or zinc oxide (ZnO). 
     The second gate insulating layer  113  may be provided to cover the first gate electrode GE 1 . Like the first gate insulating layer  112 , the second gate insulating layer  113  may include an inorganic insulating material such as silicon oxide (SiO 2 ), silicon nitride (SiN x ), silicon oxynitride (SiON), aluminum oxide (Al 2 O 3 ), titanium oxide (TiO 2 ), tantalum oxide (Ta 2 O 5 ), hafnium oxide (HfO 2 ), and/or zinc oxide (ZnO). 
     An upper electrode CE 2  of the storage capacitor Cst may be arranged over the second gate insulating layer  113 . The upper electrode CE 2  may overlap the first gate electrode GE 1  thereunder. In this case, the upper electrode CE 2  and the first gate electrode GE 1  of the driving thin film transistor T 1  overlapping each other with the second gate insulating layer  113  therebetween may form the storage capacitor Cst. That is, the first gate electrode GE 1  of the driving thin film transistor T 1  may function as a lower electrode CE 1  of the storage capacitor Cst. 
     As such, the storage capacitor Cst and the driving thin film transistor T 1  may be disposed to overlap each other. In some embodiments, the storage capacitor Cst may be disposed not to overlap the driving thin film transistor T 1 . 
     The upper electrode CE 2  may include aluminum (Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), calcium (Ca), molybdenum (Mo), titanium (Ti), tungsten (W), and/or copper (Cu) and may include a single layer or multiple layers of the above material. 
     The interlayer insulating layer  114  may cover the upper electrode CE 2 . The interlayer insulating layer  114  may include silicon oxide (SiO 2 ), silicon nitride (SiN x ), silicon oxynitride (SiON), aluminum oxide (Al 2 O 3 ), titanium oxide (TiO 2 ), tantalum oxide (Ta 2 O 5 ), and hafnium oxide (HfO 2 ), or zinc oxide (ZnO). The interlayer insulating layer  114  may include a single layer or a multiple layer including the above inorganic insulating material. 
     Each of the first drain electrode DE 1  and the first source electrode SE 1  may be arranged over the interlayer insulating layer  114 . Each of the first drain electrode DE 1  and the first source electrode SE 1  may include a high-conductivity material. The first drain electrode DE 1  and the first source electrode SE 1  may include a conductive material including molybdenum (Mo), aluminum (Al), copper (Cu), titanium (Ti), or the like and may include a single layer or multiple layers including the above material. In an embodiment, the first drain electrode DE 1  and the first source electrode SE 1  may include a multilayer structure of Ti/Al/Ti. 
     The switching thin film transistor T 2  may include a second semiconductor layer ACT 2 , a second gate electrode GE 2 , a second drain electrode DE 2 , and a second source electrode SE 2 . The second semiconductor layer ACT 2 , the second gate electrode GE 2 , the second drain electrode DE 2 , and the second source electrode SE 2  may be similar to the first semiconductor layer ACT 1 , the first gate electrode GE 1 , the first drain electrode DE 1 , and the first source electrode SE 1 , respectively, and thus, redundant descriptions thereof will be omitted for conciseness. 
     The first organic insulating layer  115  may be arranged to cover the first drain electrode DE 1  and the first source electrode SE 1 . The first organic insulating layer  115  may include an organic material. For example, the first organic insulating layer  115  may include an organic insulating material such as a general-purpose polymer such as polymethylmethacrylate (“PMMA”) or polystyrene (“PS”), a polymer derivative having a phenolic group, an acryl-based polymer, an imide-based polymer, an arylether-based polymer, an amide-based polymer, a fluorine-based polymers, a p-xylene-based polymer, a vinyl alcohol-based polymer, or any blend thereof. 
     A connection electrode CML may be arranged over the first organic insulating layer  115 . In this case, the connection electrode CML may be connected to the first drain electrode DE 1  or the first source electrode SE 1  through a contact hole of the first organic insulating layer  115 . The connection electrode CML may include a high-conductivity material. The connection electrode CML may include a conductive material including molybdenum (Mo), aluminum (Al), copper (Cu), titanium (Ti), or the like and may include a single layer or multiple layers including the above material. In an embodiment, the connection electrode CML may include a multilayer structure of Ti/Al/Ti. 
     The second organic insulating layer  116  may be arranged to cover the connection electrode CML. The second organic insulating layer  116  may include an organic material. The second organic insulating layer  116  may include an organic insulating material such as a general-purpose polymer such as polymethylmethacrylate (PMMA) or polystyrene (PS), a polymer derivative having a phenolic group, an acrylic polymer, an imide-based polymer, an arylether-based polymer, an amide-based polymer, a fluorine-based polymers, a p-xylene-based polymer, a vinyl alcohol-based polymer, or any blend thereof. 
     The display element layer DEL may be arranged over the pixel circuit layer PCL. The display element layer DEL may include an organic light emitting diode OLED. 
     A pixel electrode  211  of the organic light emitting diode OLED may be electrically connected to the connection electrode CML through a contact hole of the second organic insulating layer  116 . The pixel electrode  211  may include a conductive oxide such as indium tin oxide (“ITO”), indium zinc oxide (“IZO”), zinc oxide (ZnO), indium oxide (In 2 O 3 ), indium gallium oxide (“IGO”), or aluminum zinc oxide (“AZO”). In other embodiments, the pixel electrode  211  may include a reflection layer including silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), or any compound thereof. In other embodiments, the pixel electrode  211  may further include a layer formed of or including ITO, IZO, ZnO, or In 2 O 3  over/under the reflection layer. 
     A pixel definition layer  118  defining an opening  118 OP exposing a central portion of the pixel electrode  211  may be arranged over the pixel electrode  211 . The pixel definition layer  118  may include an organic insulating material and/or an inorganic insulating material. The opening  118 OP may define an emission area of light emitted from the organic light emitting diode OLED. For example, the width of the opening  118 OP may correspond to the width of the emission area. 
     A spacer  119  may be arranged over the pixel definition layer  118 . In the case of a method of manufacturing the display panel  10 , a mask sheet may be used, and in this case, the mask sheet may enter the opening  118 OP of the pixel definition layer  118  or may contact the pixel definition layer  118 . The spacer  119  may prevent a defect in which a portion of the multilayer and the substrate  100  is damaged by the mask sheet when a deposition material is deposited on the substrate  100 . 
     The spacer  119  may include an organic material such as polyimide. Alternatively, the spacer  119  may include an inorganic insulating material such as silicon nitride (SiN x ) or silicon oxide (SiO 2 ) or may include an organic insulating material and an inorganic insulating material. 
     In an embodiment, the spacer  119  may include a different material from the material of the pixel definition layer  118 . Alternatively, in other embodiments, the spacer  119  may include the same material as the pixel definition layer  118 , and in this case, the pixel definition layer  118  and the spacer  119  may be formed together in a mask process using a halftone mask or the like. 
     An intermediate layer  212  may be arranged over the pixel definition layer  118 . The intermediate layer  212  may include an emission layer  212   b  arranged in the opening  118 OP of the pixel definition layer  118 . The emission layer  212   b  may include a high-molecular or low-molecular weight organic material for emitting light of a certain color. 
     A first functional layer  212   a  and a second functional layer  212   c  may be arranged under and over the emission layer  212   b , respectively. The first functional layer  212   a  may include, for example, a hole transport layer (“HTL”) or may include an HTL and a hole injection layer (“HIL”). The second functional layer  212   c  may be a component arranged over the emission layer  212   b  and may be optional. The second functional layer  212   c  may include an electron transport layer (“ETL”) and/or an electron injection layer (“EIL”). Like an opposite electrode  213  described below, the first functional layer  212   a  and/or the second functional layer  212   c  may be a common layer to entirely cover the substrate  100 . 
     An opposite electrode  213  may include a conductive material having a low work function. For example, the opposite electrode  213  may include a (semi)transparent layer including silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), or any alloy thereof. Alternatively, the opposite electrode  213  may further include a layer such as ITO, IZO, ZnO, or In 2 O 3  over the (semi)transparent layer including the above material. 
     In some embodiments, a capping layer (not illustrated) may be further arranged over the opposite electrode  213 . The capping layer may include LiF, an inorganic material, and/or an organic material. 
     The encapsulation layer ENL may be arranged over the opposite electrode  213 . In an embodiment, the encapsulation layer ENL may include at least one inorganic encapsulation layer and at least one organic encapsulation layer. In an embodiment,  FIG. 12  illustrates that the encapsulation layer ENL includes a first inorganic encapsulation layer  310 , an organic encapsulation layer  320 , and a second inorganic encapsulation layer  330  that are sequentially stacked. 
     The first inorganic encapsulation layer  310  and the second inorganic encapsulation layer  330  may include one or more inorganic materials among aluminum oxide (Al 2 O 3 ), titanium oxide (TiO 2 ), tantalum oxide (Ta 2 O 5 ), hafnium oxide (HfO 2 ) zinc oxide (ZnO), silicon oxide (SiO 2 ), silicon nitride (SiN x ), and silicon oxynitride (SiON). The organic encapsulation layer  320  may include a polymer-based material. The polymer-based material may include acryl-based resin, epoxy-based resin, polyimide, polyethylene, or the like. In an embodiment, the organic encapsulation layer  320  may include acrylate. 
     Although not illustrated, a touch electrode layer may be arranged over the encapsulation layer ENL, and an optical functional layer may be arranged over the touch electrode layer. The touch electrode layer may be configured to obtain coordinate information according to an external input, for example, a touch event. The optical functional layer may reduce the reflectance of light (external light) incident from the outside toward the display apparatus and/or may improve the color purity of light emitted from the display apparatus. In an embodiment, the optical functional layer may include a phase retarder and/or a polarizer. The phase retarder may be a film type or a liquid crystal coating type and may include a λ/2 phase retarder and/or a λ/4 phase retarder. The polarizer may also be a film type or a liquid crystal coating type. The film type may include a stretched synthetic resin film, and the liquid crystal coating type may include liquid crystals arranged in a certain arrangement. The phase retarder and the polarizer may further include a protection film. 
     In other embodiments, the optical functional layer may include a black matrix and color filters. The color filters may be arranged in consideration of the color of light emitted from each of the pixels of the display panel. Each of the color filters may include a red, green, or blue pigment or dye. Alternatively, each of the color filters may further include quantum dots in addition to the above pigment or dye. Alternatively, some of the color filters may not include the above pigment or dye and may include scattering particles such as titanium oxide. 
     In other embodiments, the optical functional layer may include a destructive interference structure. The destructive interference structure may include a first reflection layer and a second reflection layer arranged on different layers. First reflected light and second reflected light reflected by the first reflection layer and the second reflection layer, respectively, may destructively interfere with each other, and accordingly, the external light reflectance may be reduced. 
     An adhesive member may be arranged between the touch electrode layer and the optical functional layer. The adhesive member may include a general one known in the art, without limitation. The adhesive member may include a pressure sensitive adhesive (“PSA”). 
     In an embodiment, the stack structure of the display panel  10  of  FIG. 12  may be generally used in the front area FA and the corner area CA of  FIG. 10 . In other embodiments, the stack structure of the display panel  10  in the front area FA may be different from the stack structure of the display panel  10  in the corner area CA. Hereinafter, a detailed description will be mainly given of a case where the stack structure of the display panel  10  in the front area FA is different from the stack structure of the display panel  10  in the corner area CA. 
       FIG. 13  is a plan view schematically illustrating a corner area CA according to an embodiment.  FIG. 13  is an enlarged view of region XIII of the display panel  10  of  FIG. 10 . 
     Referring to  FIG. 13 , the display panel  10  may include an edge. The edge may be an end portion of the display panel  10 . In an embodiment, the display panel  10  may include a corner edge CEd. 
     The display panel  10  may include a substrate  100 . The substrate  100  may include a front area FA and a corner area CA. The corner area CA may extend from the front area FA to the corner edge CEd. 
     The corner area CA may include a first area R 1  and a second area R 2  spaced apart from each other. In an embodiment, the display panel  10  may provide a through-portion TP at least partially defined by an edge RE 1  of the first area R 1  and an edge RE 2  of the second area R 2 . The edge RE 1  of the first area R 1  may be an end portion of the first area R 1 . The edge RE 2  of the second area R 2  may be an end portion of the second area R 2 . 
     The through-portion TP may pass through the display panel  10 . Thus, the components of the display panel  10  may not be arranged in the through-portion TP. Because the through-portion TP is defined between the first area R 1  and the second area R 2  adjacent to each other, when the display panel  10  is curved, the first area R 1  and the second area R 2  may be stretched or contracted. That is, in  FIG. 13 , the through-portion TP may be an empty space between the first area R 1  and the second area R 2 . Thus, when the display panel  10  is curved in the corner area CA, the display panel  10  may be curved without damage and the through-portion TP may improve the flexibility of the display panel  10 . 
     In an embodiment, each of the first area R 1  and the second area R 2  may extend from the front area FA to the corner edge CEd. Each of the first area R 1  and the second area R 2  may extend in a direction away from the front area FA. In this case, the edge RE 1  of the first area R 1  and the edge RE 2  of the second area R 2  may face each other. 
     A pixel PX may be arranged over the substrate  100 . In an embodiment, the pixel PX may be arranged over the substrate  100  to overlap at least one of the corner area CA and the front area FA. 
     In an embodiment, the pixel PX may include a first pixel PX 1  and a second pixel PX 2 . The first pixel PX 1  may be arranged over the substrate  100  to overlap the first area R 1 . A plurality of first pixels PX 1  may be provided in the first area R 1 . The second pixel PX 2  may be arranged over the substrate  100  to overlap the second area R 2 . A plurality of second pixels PX 2  may be provided in the second area R 2 . The first pixel PX 1  and the second pixel PX 2  may face each other with the through-portion TP therebetween. 
     In an embodiment, a driving circuit DC for driving the pixel PX may be arranged in the corner area CA. In this case, a portion of the pixel PX may overlap the driving circuit DC. The driving circuit DC may be a scan driving circuit for providing a scan signal to each pixel PX through a scan line. Alternatively, the driving circuit DC may be a data driving circuit (not illustrated) for providing a data signal to each pixel PX through a data line. In some embodiments, the driving circuit DC may be omitted. 
       FIGS. 14A and 14B  are plan views schematically illustrating a corner area CA according to an embodiment.  FIGS. 14A and 14B  are enlarged views of region XIV of the display panel  10  of  FIG. 10 . 
     Referring to  FIGS. 14A and 14B , the corner area CA may include a first area R 1  and a second area R 2  spaced apart from each other. In an embodiment, the display panel  10  may provide a through-portion TP at least partially defined by an edge RE 1  of the first area R 1  and an edge RE 2  of the second area R 2 . The edge RE 1  of the first area R 1  may be an end portion of the first area R 1 . The edge RE 2  of the second area R 2  may be an end portion of the second area R 2 . 
     The through-portion TP may pass through the display panel  10 . Thus, the components of the display panel  10  may not be arranged in the through-portion TP. Because the through-portion TP is defined between the first area R 1  and the second area R 2  adjacent to each other, when the display panel  10  is curved in the corner area CA, the display panel  10  may be curved without damage. Thus, the through-portion TP may improve the flexibility of the display panel  10 . 
     In an embodiment, the pixel PX may be arranged over the substrate  100  to overlap the corner area CA. In an embodiment, the pixel PX may include a first pixel PX 1  and a second pixel PX 2 . The first pixel PX 1  may be arranged over the substrate  100  to overlap the first area R 1 . The second pixel PX 2  may be arranged over the substrate  100  to overlap the second area R 2 . The first pixel PX 1  and the second pixel PX 2  may face each other with the through-portion TP therebetween. 
     Referring to  FIG. 14A , the corner area CA may include a first area R 1 , a second area R 2 , a first extension area ETR 1 , and a second extension area ETR 2 . 
     The first area R 1  and the second area R 2  may be spaced apart in a first extension direction EDR 1 . In other embodiments, the first area R 1  and the second area R 2  may be spaced apart in a second extension direction EDR 2 . In an embodiment, the first extension direction EDR 1  may be the same as the first direction (e.g., x direction or −x direction) of  FIG. 10 . In other embodiments, the first extension direction EDR 1  may be a direction intersecting with the first direction (e.g., x direction or −x direction) of  FIG. 10 . 
     In an embodiment, the second extension direction EDR 2  may be the same as the second direction (e.g., y direction or −y direction) of  FIG. 10 . In other embodiment, the second extension direction EDR 2  may be a direction intersecting with the second direction (e.g., y direction or −y direction) of  FIG. 10 . 
     The first extension area ETR 1  may extend in the first extension direction EDR 1 . The second extension area ETR 2  may extend in the second extension direction EDR 2 . The first extension direction EDR 1  and the second extension direction EDR 2  may intersect with each other. In an embodiment, the first extension direction EDR 1  and the second extension direction EDR 2  may be perpendicular to each other. In other embodiments, the first extension direction EDR 1  and the second extension direction EDR 2  may form an acute angle or an obtuse angle therebetween. Hereinafter, a detailed description will be mainly given of a case where the first extension direction EDR 1  and the second extension direction EDR 2  are perpendicular to each other. 
     Any one of the first extension area ETR 1  and the second extension area ETR 2  may extend from the first area R 1  to the second area R 2 . For example, the first extension area ETR 1  may extend from the first area R 1  to the second area R 2 . Thus, the first area R 1 , the first extension area ETR 1 , and the second area R 2  may be integrally provided. The first area R 1 , the first extension area ETR 1 , and the second area R 2  may be connected to each other. 
     A connection line may be arranged in the first extension area ETR 1  and the second extension area ETR 2 . For example, the connection line may include a signal line for transmitting an electrical signal to the pixel PX and/or a power line for supplying a voltage. 
     The edge of any one of the first extension area ETR 1  and the second extension area ETR 2 , the edge RE 1  of the first area R 1 , and the edge RE 2  of the second area R 2  may define at least a portion of the through-portion TP. In an embodiment, an edge ETRE 1  of the first extension area ETR 1 , the edge RE 1  of the first area R 1 , and the edge RE 2  of the second area R 2  may define at least a portion of the through-portion TP. In an embodiment, the edge ETRE 1  of the first extension area ETR 1 , an edge ETRE 2  of the second extension area ETR 2 , the edge RE 1  of the first area R 1 , and the edge RE 2  of the second area R 2  may define at least a portion of the through-portion TP. 
     Any one of the first area R 1  and the second area R 2 , a portion of the first extension area ETR 1  extending therefrom, and a portion of the second extension area ETR 2  may be defined as one basic unit U. The basic unit U may be repeatedly arranged in the first extension direction EDR 1  and/or the second extension direction EDR 2 , and the substrate  100  may be understood as being provided by connecting the repeatedly arranged basic units U to each other. Two basic units U adjacent to each other may be symmetrical to each other. For example, in  FIG. 14A , two basic units U adjacent to each other in the horizontal direction may be horizontally symmetrical with respect to a symmetry axis that is located therebetween and is parallel to the second extension direction EDR 2 . Similarly, in  FIG. 14A , two basic units U adjacent to each other in the vertical direction may be vertically symmetrical with respect to a symmetry axis that is located therebetween and is parallel to the first extension direction EDR 1 . 
     Among a plurality of basic units U, adjacent basic units U, for example, four basic units U illustrated in  FIG. 14A  may form a closed curve CC therebetween, wherein the closed curve CC may define a separation area V that is an empty space. The separation area V may be defined by a closed curve CC formed by the edge RE 1  of the first area R 1 , the edge RE 2  of the second area R 2 , the edge ETRE 1  of the first extension area ETR 1 , and the edge ETRE 2  of the second extension area ETR 2 . The separation area V may overlap the through-portion TP of the display panel. 
     Referring to  FIG. 14B , the corner area CA may include a first area R 1 , a second area R 2 , and an extension area ETR. In an embodiment, the first area R 1  and the second area R 2  may be spaced apart from each other in a direction intersecting with the first extension direction EDR 1  and the second extension direction EDR 2 . 
     The extension area ETR may extend from the first area R 1  to the second area R 2 . The extension direction of the extension area ETR may change at least two times. In an embodiment, the extension area ETR may extend in a first direction and then may extend in a second direction intersecting with the first direction and may extend in a third direction intersecting with the second direction. In this case, the first direction and the third direction may be the same as each other. The extension area ETR may extend serpentinely. In an embodiment, the extension area ETR may extend in a sine curve shape. 
     The extension areas ETR may be provided as a plurality of extension areas. The plurality of extension areas ETR may be spaced apart from each other. A connection line may be arranged in the extension area ETR. For example, the connection line may include a signal line for transmitting an electrical signal to the pixel PX and/or a power line for supplying a voltage. 
     In an embodiment, the adjacent extension areas ETR may be symmetrically arranged with respect to a direction in which the first and second areas R 1  and R 2  are spaced apart from each other. For example, the first extension area ETR 1  and the second extension area ETR 2  may extend serpentinely. The first area R 1  and the second area R 2  may be connected to the first extension area ETR 1  and the second extension area ETR 2 , respectively. In this case, the first extension area ETR 1  and the second extension area ETR 2  adjacent to each other may be symmetrically arranged with respect to a direction in which the first area R 1  and the second area R 2  adjacent to each other are spaced apart from each other. 
     An edge ETRE of the extension area ETR, the edge RE 1  of the first area R 1 , and the edge RE 2  of the second area R 2  may define at least a portion of the through-portion TP. The edge RE 1  of the first area R 1 , the edge RE 2  of the second area R 2 , the edge ETRE 1  of the first extension area ETR 1 , and the edge ETRE 2  of the second extension area ETR 2 , which are adjacent to each other, may define a through-portion TP. In other words, the edge RE 1  of the first area R 1 , the edge RE 2  of the second area R 2 , the edge ETRE 1  of the first extension area ETR 1 , and the edge ETRE 2  of the second extension area ETR 2 , which are adjacent to each other, may form a closed curve CC. The closed curve CC may define a separation area V that is an empty space. The separation area V may overlap the through-portion TP of the display panel. 
     The embodiment of  FIGS. 14A and 14B  have been described above as being applied to the corner area CA; however, in other embodiments, the shape of the substrate  100  of  FIGS. 14A and/or 14B  may be generally applied to the front area FA and the corner area CA of  FIG. 10 . 
       FIG. 15  is a cross-sectional view schematically illustrating a display panel  10  in a corner area CA according to an embodiment. In  FIG. 15 , like reference numerals as those in  FIG. 12  denote like members, and thus, redundant descriptions thereof will be omitted for conciseness. 
     Referring to  FIG. 15 , a substrate  100  of the display panel  10  may include a corner area CA. The corner area CA may include a first area R 1  and a second area R 2  spaced apart from each other, and the edge of the first area R 1  and the edge of the second area R 2  may at least partially define a through-portion TP of the display panel  10 . 
     The display panel  10  may include a substrate  100 , a buffer layer  111 , a pixel circuit layer PCL, a display element layer DEL, and an encapsulation layer ENL. In an embodiment, the substrate  100 , the buffer layer  111 , the pixel circuit layer PCL, the display element layer DEL, and the encapsulation layer ENL may be separated with the through-portion TP therebetween. In an embodiment, the pixel circuit layer PCL may further include a first inorganic layer PVX 1 . In an embodiment, the display element layer DEL may further include a second inorganic layer PVX 2 . 
     Hereinafter, a stack structure of the display panel  10  including the through-portion TP will be described in detail. However, the stack structure of the display panel  10  including the through-portion TP is not limited thereto, and various embodiments thereof may be possible. 
     A first organic insulating layer  115  and a second organic insulating layer  116  may define a hole HL. In an embodiment, the hole HL may be provided by overlapping a hole of the first organic insulating layer  115  and a hole of the second organic insulating layer  116  each other. In other embodiments, the hole HL may be provided in the second organic insulating layer  116 . In this case, the upper surface of the first organic insulating layer  115  may be exposed by the hole of the second organic insulating layer  116 . Hereinafter, a detailed description will be mainly given a case where the hole HL is provided in the first organic insulating layer  115  and the second organic insulating layer  116 . 
     In an embodiment, the first inorganic layer PVX 1  may be arranged between an interlayer insulating layer  114  and the first organic insulating layer  115 . The first inorganic layer PVX 1  may cover a first source electrode SE 1 , a first drain electrode DE 1 , a second source electrode SE 2 , and a second drain electrode DE 2 . In an embodiment, the first inorganic layer PVX 1  may define a contact hole such that the first source electrode SE 1  or the first drain electrode DE 1  may be electrically connected to a connection electrode CML. 
     In other embodiment, the first inorganic layer PVX 1  may be arranged between the first organic insulating layer  115  and the second organic insulating layer  116 . In this case, the first inorganic layer PVX 1  may cover the connection electrode CML. At least a portion of the first inorganic layer PVX 1  may be exposed by the hole HL. The first inorganic layer PVX 1  may include a single layer or multiple layers including an inorganic material such as silicon nitride (SiN x ) and/or silicon oxide (SiO 2 ). In some embodiments, the first inorganic layer PVX 1  may be omitted. 
     An organic light emitting diode OLED may be arranged over the second organic insulating layer  116 . The organic light emitting diode OLED may include a first organic light emitting diode OLED 1  and a second organic light emitting diode OLED 2 . The first organic light emitting diode OLED 1  may be arranged as a first display element over the substrate  100  to overlap the first area R 1 . The first organic light emitting diode OLED 1  may implement a first pixel PX 1 . The second organic light emitting diode OLED 2  may be arranged as a second display element over the substrate  100  to overlap the second area R 2 . The second organic light emitting diode OLED 2  may implement a second pixel PX 2 . 
     The first organic light emitting diode OLED 1  may include a first pixel electrode  211 A, an intermediate layer  212 , and an opposite electrode  213 . The second organic light emitting diode OLED 2  may include a second pixel electrode  211 B, an intermediate layer  212 , and an opposite electrode  213 . Each of the first pixel electrode  211 A and the second pixel electrode  211 B may be connected to the connection electrode CML through a contact hole of the second organic insulating layer  116 . 
     The second inorganic layer PVX 2  may be arranged between the organic light emitting diode OLED and the second organic insulating layer  116 . The second inorganic layer PVX 2  may include a plurality of inorganic patterns spaced apart from each other over the second organic insulating layer  116 . The second inorganic layer PVX 2  may include a protrusion tip PT protruding toward the center of the hole HL. Thus, the lower surface of the protrusion tip PT may be exposed through the hole HL. That is, the hole HL may have an undercut structure. The second inorganic layer PVX 2  may include a single layer or multiple layers including an inorganic material such as silicon nitride (SiN x ) and/or silicon oxide (SiO 2 ). 
     The hole HL and the protrusion tip PT of the second inorganic layer PVX 2  may be a structure for disconnecting a first functional layer  212   a  and a second functional layer  212   c . In an embodiment, the first functional layer  212   a , the second functional layer  212   c , and the opposite electrode  213  may be disposed over the front surface of the substrate  100 . In this case, the first functional layer  212   a  and the second functional layer  212   c  may include an organic material, and external oxygen or moisture or the like may flow into the organic light emitting diode OLED from the through-portion TP through at least one of the first functional layer  212   a  and the second functional layer  212   c . Alternatively, such oxygen or moisture may damage the organic light emitting diode OLED. The hole HL and the protrusion tip PT of the second inorganic layer PVX 2  may disconnect the first functional layer  212   a  and the second functional layer  212   c , and the disconnected first functional layer pattern and second functional layer pattern may be arranged inside the hole HL. Thus, the inflow of moisture or oxygen into the organic light emitting diode OLED from the through-portion TP may be prevented, and damage to the organic light emitting diode OLED may be prevented. However, the structure for disconnecting the first functional layer  212   a  and the second functional layer  212   c  is not limited thereto, and various structures for disconnecting the first functional layer  212   a  and the second functional layer  212   c  may be applied to the display panel  10 . 
     A first dam unit DAM 1  and a second dam unit DAM 2  may be arranged over the second inorganic layer PVX 2 . The first dam unit DAM 1  and the second dam unit DAM 2  may protrude from the second inorganic layer PVX 2  in the thickness direction of the substrate  100 . The first dam unit DAM 1  and the second dam unit DAM 2  may be arranged adjacent to the through-portion TP. 
     The first dam unit DAM 1  may be arranged over the first area R 1 . In an embodiment, the first dam unit DAM 1  may surround the first organic light emitting diode OLED 1 . The first dam unit DAM 1  may be arranged closer to the through-portion TP than the hole HL. The first dam unit DAM 1  may include a first pattern layer  118 D 1  and a first upper pattern layer  119 D 1 . In an embodiment, the first pattern layer  118 D 1  may include the same material as a pixel definition layer  118 . The first upper pattern layer  119 D 1  may include an organic insulating material and/or an inorganic insulating material. 
     The second dam unit DAM 2  may be arranged over the second area R 2 . In an embodiment, the second dam unit DAM 2  may surround the second organic light emitting diode OLED 2 . The second dam unit DAM 2  may be arranged closer to the through-portion TP than the hole HL. The second dam unit DAM 2  may include a second pattern layer  118 D 2  and a second upper pattern layer  119 D 2 . In an embodiment, the second pattern layer  118 D 2  may include the same material as the pixel definition layer  118  and the first pattern layer  118 D 1 . The pixel definition layer  118 , the first pattern layer  118 D 1 , and the second pattern layer  118 D 2  may be simultaneously formed. The second upper pattern layer  119 D 2  may include an organic insulating material and/or an inorganic insulating material. The second upper pattern layer  119 D 2  may include the same material as the first upper pattern layer  119 D 1 . The first upper pattern layer  119 D 1  and the second upper pattern layer  119 D 2  may be simultaneously formed. In some embodiments, at least one of the first dam unit DAM 1  and the second dam unit DAM 2  may be omitted. 
     The encapsulation layer ENL may cover the first organic light emitting diode OLED 1  and the second organic light emitting diode OLED 2 . The encapsulation layer ENL may be arranged over the opposite electrode  213 . The encapsulation layer ENL may be separated with the through-portion TP therebetween. In an embodiment, the encapsulation layer ENL may include at least one inorganic encapsulation layer and at least one organic encapsulation layer. In an embodiment,  FIG. 15  illustrates that the encapsulation layer ENL includes a first inorganic encapsulation layer  310 , an organic encapsulation layer  320 , and a second inorganic encapsulation layer  330  that are sequentially stacked. 
     The first inorganic encapsulation layer  310  may cover the organic light emitting diode OLED. The first inorganic encapsulation layer  310  may entirely and continuously cover the substrate  100 . The first inorganic encapsulation layer  310  may cover the first organic light emitting diode OLED 1 , the hole HL, the first dam unit DAM 1 , the second dam unit DAM 2 , and the second organic light emitting diode OLED 2 . The first inorganic encapsulation layer  310  may contact the protrusion tip PT of the second inorganic layer PVX 2 . The first inorganic encapsulation layer  310  may contact the first inorganic layer PVX 1 . Thus, it may be possible to prevent moisture or oxygen from flowing from the through-portion TP into the organic light emitting diode OLED through a layer including an organic material. Also, the first inorganic encapsulation layer  310  may be separated with respect to the through-portion TP. 
     The organic encapsulation layer  320  may be arranged over the first inorganic encapsulation layer  310 . The organic encapsulation layer  320  may overlap the first organic light emitting diode OLED 1  and the second organic light emitting diode OLED 2 , and the organic encapsulation layer  320  may fill the hole HL. In an embodiment, the organic encapsulation layer  320  may be separated with respect to the through-portion TP. For example, the organic encapsulation layer  320  overlapping the first organic light emitting diode OLED 1  may extend to the first dam unit DAM 1 . The organic encapsulation layer  320  overlapping the second organic light emitting diode OLED 2  may extend to the second dam unit DAM 2 . Because the first dam unit DAM 1  and the second dam unit DAM 2  protrude from the upper surface of the second inorganic layer PVX 2  in the thickness direction of the substrate  100 , the flow of the material forming the organic encapsulation layer  320  may be controlled. 
     The second inorganic encapsulation layer  330  may cover the organic encapsulation layer  320 . The second inorganic encapsulation layer  330  may entirely and continuously cover the substrate  100 . The second inorganic encapsulation layer  330  may contact the first inorganic encapsulation layer  310  over the first dam unit DAM 1  and the second dam unit DAM 2 . Thus, the organic encapsulation layer  320  may be separated by the first dam unit DAM 1  and the second dam unit DAM 2 . Also, the second inorganic encapsulation layer  330  may be separated with respect to the through-portion TP. 
     As described above, in the display panel according to the embodiments, because the display panel is curved in the corner area in the direction in which the corner edge approaches the center of the display panel, a screen distortion viewed by the user of the electronic apparatus may be reduced. 
     It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.