Display device and fabrication method thereof

A display device comprising:

• a first optical adjustment layer and a second optical adjustment layer;
• a first insulating layer over the first optical adjustment layer and the second optical adjustment layer;
• a first plug and a second plug over the first insulating layer;
• a first light-emitting element over the first insulating layer, the first light-emitting element overlapping with the first optical adjustment layer and electrically connected to the first plug;
• and
• a second light-emitting element over the first insulating layer, the second light-emitting element overlapping with the second optical adjustment layer and electrically connected to the second plug,
• wherein each of the first light-emitting element and the second light-emitting element comprises a lower electrode having a light-transmitting property, a light-emitting layer, and an upper electrode having a semi-transmissive property and a semi-reflective property, wherein at least top surfaces of the first optical adjustment layer and the second optical adjustment layer are each configured to reflect visible light,
• wherein the first optical adjustment layer is thinner than the second optical adjustment layer,
• wherein the first plug is positioned inside a first opening of the first insulating layer,
• wherein the second plug is positioned inside a second opening of the first insulating layer,
• wherein the first plug is electrically connected to the first optical adjustment layer,
• wherein the second plug is electrically connected to the second optical adjustment layer,
• wherein the first optical adjustment layer serves as one electrode of a first capacitor, and
• wherein the second optical adjustment layer serves as one electrode of a second capacitor.