Patent ID: 8319420

Claim:
An organic light emitting diode display, including at least one organic light emitting diode (OLED) comprising: a first electrode; a hole injection layer on the first electrode; an emission layer on the hole injection layer; an electron injection layer on the emission layer; and a second electrode on the electron injection layer, wherein an absolute value of a difference between a work function of the first electrode and a work function of the second electrode is less than 0.5 eV, and the first electrode and the second electrode include materials different from each other; wherein the hole injection layer is an at least three-layer multilayer that includes a first hole injection layer, a second hole injection layer, and a third hole injection layer, wherein: an energy level of the second hole injection layer is less than an energy level of the third hole injection layer, an energy level of the first hole injection layer is less than the energy level of the second hole injection layer, the first hole injection layer is closest to the first electrode of the first, second, and third hole injection layers, and the third hole injection layer is farthest from the first electrode of the first, second, and third hole injection layers; and wherein the electron injection layer is an at least three-layer multilayer that includes a first electron injection layer, a second electron injection layer, and a third electron injection layer, wherein: an energy level of the second electron injection layer is less than an energy level of the third electron injection layer, an energy level of the first electron injection layer is less than the energy level of the second electron injection layer, the first electron injection layer is farthest from the second electrode of the first, second, and third electron injection layers, and the third electron injection layer is closest to the second electrode of the first, second, and third electron injection layers.