Investigations on multicolor display by organic luminescent devices with optical microcavity structure

The emitted light of an organic electroluminescent (EL) device has a narrow half-width in its spectrum and its intensity is high if a semitransparent mirror is placed on the light-emitting side and the optical distance between the mirror and a metal electrode is set on the order of the emitting wavelength. This phenomenon is believed to be due to microcavity formation. This paper shows that device characteristics can be explained qualitatively by equations derived from the propagations. It is also shown that it is possible to obtain different colors from the same device material using this characteristic. The basic device structure for multicolor display will be shown. The dependence of luminescence on the detecting angle is theoretically and experimentally confirmed, and it is concluded that the device can be used for display applications.