Display device and method of manufacturing flexible printed circuit board

A display device comprising:

• a display panel including a display surface and a rear surface which is opposite to the display surface;
• and
• a flexible printed circuit board attachable to the display panel at the rear surface of the display panel,
• wherein
• the flexible printed circuit board includes a conductive layer, a passivation layer defining an outer surface of the flexible printed circuit board, and a base film between the conductive layer and the passivation layer,
• the outer surface includes a first region of the passivation layer at which the rear surface of the display panel is attachable to the flexible printed circuit board and a second region of the passivation layer at which the rear surface of the display panel is not attached to the flexible printed circuit board, and
• the first region of the passivation layer has a greater surface roughness than the second region of the passivation layer.