A display device comprising: a substrate ; an encapsulation portion on the substrate ; a seal portion between the substrate and the encapsulation portion ; and at least one dummy seal portion adjacent to the seal portion , wherein: the substrate and the encapsulation portion at least partially overlap each other in a first direction perpendicular to a surface of the substrate ; and the dummy seal portion is, when viewed in the first direction, arranged in an area between an edge of the seal portion and a boundary line of an overlapping area of the substrate and the encapsulation portion , wherein: the seal portion encompasses an active area of the substrate when viewed in the first direction; and the dummy seal portion is arranged, when viewed in the first direction, outside the active area and the seal portion , wherein, when viewed in the first direction: an area of the substrate extends beyond the boundary line; pad terminals are arranged in the area extending beyond the boundary line; signal lines are respectively connected to the pad terminals ; and the signal lines cross the boundary line, wherein: the dummy seal portion is spaced apart from the seal portion when viewed in the first direction; characterized in that the dummy seal portion comprises at least one island shape. a substrate ; an encapsulation portion on the substrate ; a seal portion between the substrate and the encapsulation portion ; and at least one dummy seal portion adjacent to the seal portion , wherein: the substrate and the encapsulation portion at least partially overlap each other in a first direction perpendicular to a surface of the substrate ; and the dummy seal portion is, when viewed in the first direction, arranged in an area between an edge of the seal portion and a boundary line of an overlapping area of the substrate and the encapsulation portion , wherein: the seal portion encompasses an active area of the substrate when viewed in the first direction; and the dummy seal portion is arranged, when viewed in the first direction, outside the active area and the seal portion , the seal portion encompasses an active area of the substrate when viewed in the first direction; and the dummy seal portion is arranged, when viewed in the first direction, outside the active area and the seal portion , wherein, when viewed in the first direction: an area of the substrate extends beyond the boundary line; pad terminals are arranged in the area extending beyond the boundary line; signal lines are respectively connected to the pad terminals ; and the signal lines cross the boundary line, wherein: the dummy seal portion is spaced apart from the seal portion when viewed in the first direction; characterized in that the dummy seal portion comprises at least one island shape. an area of the substrate extends beyond the boundary line; pad terminals are arranged in the area extending beyond the boundary line; signal lines are respectively connected to the pad terminals ; and the signal lines cross the boundary line, wherein: the dummy seal portion is spaced apart from the seal portion when viewed in the first direction; characterized in that the dummy seal portion comprises at least one island shape. the dummy seal portion is spaced apart from the seal portion when viewed in the first direction; characterized in that the dummy seal portion comprises at least one island shape. <EOS>