Patent ID: 7400088

Claim:
An organic electroluminescent display device, comprising: a substrate including a first pixel region, a second pixel region, and a third pixel region; a plurality of first electrodes formed on the substrate in each of the first, second, and third pixel regions; a hole injecting layer formed on the substrate to cover the plurality of first electrodes; a first hole transporting layer formed on the hole injecting layer in the first, second, and third pixel regions; a second hole transporting layer formed on a portion of the first hole transporting layer in the second and third pixel regions; a third hole transporting layer formed on a portion of the second hole transporting layer in the third pixel region; a first light emitting layer formed on the first hole transporting layer; a second light emitting layer formed on the second hole transporting layer; a third light emitting layer formed on the third hole transporting layer; and a second electrode formed on the first, second, and third light emitting layers, wherein a thickness of the second hole transporting layer is approximately one-third (⅓) to two-thirds (⅔) of an optical wavelength difference between the first pixel region and the second pixel region, and the thickness of the third hole transporting layer is approximately one-third (⅓) to two-thirds (⅔) of an optical wavelength difference between the second pixel region and the third pixel region.