Patent ID: 7554265

Claim:
A display device comprising: a substrate; a thin film transistor including a semiconductor layer formed over the substrate; a wiring electrically connected to the semiconductor layer; a light-emitting element comprising: a first electrode electrically connected to the wiring; a light emitting layer over the first electrode; and a second electrode over the light emitting layer, and a plurality of layers formed between the substrate and the light-emitting element, including: a first layer having a refraction factor n 1 , a second layer over the first layer, having a refraction factor n 2 , and a third layer over the second layer, having a refraction factor n 3 , wherein n 1 <n 2 >n 3 , wherein an optical thickness of the second layer is substantially equal to the integral multiple of λ/2, and wherein a center wavelength of a light emitted from the light-emitting element is λ.