Display device and operation method thereof

A display device comprising:

• a first substrate and a second substrate each having flexibility;
• a third substrate and a fourth substrate each being provided between the first substrate and the second substrate, wherein the third substrate and the fourth substrate are provided next to each other and do not overlap with each other;
• a first element layer between the first substrate and the second substrate and overlapping with the third substrate and the fourth substrate, the first element layer including a display part and a first sensor element part overlapping with the display part, wherein a top surface shape of the display part is substantially rectangular;
• and
• a second element layer between the first substrate and the second substrate and overlapping with the third substrate and the fourth substrate, the second element layer including second sensor element parts, wherein the first element layer and the second element layer overlap with each other,
• wherein the second sensor element parts overlap with a first region along a first side of the display part, a second region along a second side facing the first side of the display part, and a third region located intermediate between the first side and the second side of the display part,
• wherein the second sensor element parts overlap with the third substrate and the fourth substrate,
• wherein the first sensor element part is configured to detect presence or absence of an object touching the first substrate or the second substrate, and
• wherein the second sensor element parts are configured to detect distortion of the first substrate or the second substrate.

A method for operating a display device, comprising the steps of:

• displaying a first image on a display part;
• first determining whether a curvature of an edge or a vicinity of a center region of the display part is larger than or equal to a first set value, wherein, when the curvature is smaller than the first set value, the step of first determining of the curvature is performed again;
• displaying an image for operation on the edge of the display part when the curvature is larger than or equal to the first set value;
• first detecting, on the image for operation, a position of an object touching the image;
• second detecting, on the image for operation, a change in the position of the object;
• second determining whether a curvature of the edge of the display part is larger than or equal to a second set value when the change in the position of the object is not detected in the step of second detecting, wherein when the curvature is smaller than the second set value, the step of second detecting is performed again;
• and
• changing the first image to a second image when the change in the position of the object is detected in the step of second detecting, wherein, when the curvature is larger than or equal to the second set value in the step of second determining, the step of changing is performed.