Display device, electronic device including the same and method of manufacturing display device

An electronic device comprising:

• a lower cover;
• a cover window disposed on the lower cover;
• a display device disposed between the lower cover and the cover window, the display device including:
• a base substrate including a first area, a second area, and a third area disposed between the first area and the second area;
• a display panel including the base substrate;
• a pixel disposed on a second surface of the display panel in a display area included in the first area;
• a pad disposed on the second surface of the display panel in the second area;
• a first circuit board connected to the pad;
• and
• a support layer disposed on a first surface of the display panel;
• and
• a battery disposed between the lower cover and the display device,
• wherein the support layer is disposed on the first surface of the display panel in the second area of the first to third areas.

A method of manufacturing a display device, the method comprising:

• preparing a mother substrate including a plurality of display areas and a plurality of pad areas;
• cutting the mother substrate and preparing a display cell including a first display area, a first pad area of the plurality of pad areas, a first area where the first display area is disposed, a second area where the first pad area is disposed, and a third area disposed between the first area and the second area;
• performing a driving test of the display cell using a plurality of pads of the first pad area of the display cell;
• cutting a portion of the second area of the display cell including a pad area of the plurality of pad areas so that connection between the plurality of pads of the first pad area is separated;
• preparing a reinforcing film including a base layer, a common bonding layer disposed on the base layer, a first support layer and a second support layer separated from each other on the common bonding layer and bonded to the common bonding layer with different adhesive strengths from each other, and a first bonding layer and a second bonding layer disposed on the first support layer and the second support layer, respectively, and having different adhesive strengths from each other;
• attaching the reinforcing film to a first surface of the display cell so that the first bonding layer and the second bonding layer correspond to the first area and the second area of the display cell, respectively;
• forming a first circuit board, a second circuit board, a driving chip, a first reinforcing layer, and a polarizing plate on the display cell;
• forming a board cover on a side surface of the reinforcing film, a first surface of the base layer of the reinforcing film, a side surface of the display cell, and a first surface of the first circuit board;
• cutting the display cell along a preset processing line and forming a display panel, the display cell including the reinforcing film, the first circuit board, the second circuit board, the driving chip, the first reinforcing layer, the board cover, and the polarizing plate;
• and
• separating the reinforcing film from the display panel,
• wherein in the separating the reinforcing film from the display panel, only the base layer, the common bonding layer, the first support layer, and the first bonding layer of the reinforcing film are selectively separated from the display panel, and the second support layer and the second bonding layer of the reinforcing film are not separated from the display panel and remain in the second area of the display panel.