Display element, display device, and manufacturing method of the display device

A display device comprising:

• a first pixel, a second pixel, and a third pixel comprising a first light-emitting element, a second light-emitting element, and a third light-emitting element, respectively;
• a first cap layer overlapping with the first light-emitting element, the second light-emitting element, and the third light-emitting element, the first cap layer extending from the first pixel to the third pixel through the second pixel;
• a second cap layer over the first cap layer, the second cap layer overlapping with the second light-emitting element;
• a third cap layer over the first cap layer, the third cap layer overlapping with the third light-emitting element;
• and
• a fourth cap layer over the first cap layer, the second cap layer, and the third cap layer,
• wherein the first pixel, the second pixel, and the third pixel are arranged in this order,
• the first light-emitting element, the second light-emitting element, and the third light-emitting element each comprises:
• a first electrode;
• a hole-transporting region over and in contact with the first electrode;
• an emission layer over and in contact with the hole-transporting region;
• an electron-transporting region over and in contact with the emission layer;
• and
• a second electrode over and in contact with the electron-transporting region,
• the first light-emitting element, the second light-emitting element, and the third light-emitting element are configured so that an emission wavelength of the second light-emitting element is shorter than an emission wavelength of the third light-emitting element and longer than an emission wavelength of the first light-emitting element, and
• a thickness of the third cap layer is larger than a thickness of the second cap layer.