Micro-optical resonator type organic electroluminescent device

A micro-optical resonator organic electroluminescent device comprising:

• a multi-layered mirror having two alternately laminated layers with different refractive indexes;
• a transparent conductive layer as an anode formed on said multi-layered mirror;
• an organic compound layer of a single layer or a plurality of layers formed on said transparent conductive layer;
• and
• a metal mirror, as a cathode, capable of reflecting light, said multi-layered mirror and said metal mirror forming a micro-optical resonator for enhancing light output from said organic compound layer,
• wherein an optical length L of the micro-optical resonator is such that radiation from the micro-optical resonator has a single mode spectrum free of low mode components, said optical length L of said micro-optical resonator is given by the equation set forth below which takes into account the penetration depth of light into the inside of said multi-layered mirror, ##EQU4## where .lambda. is the wavelength of a resonating light, neff is the effective refractive index of the multi-layered mirror, .DELTA.n is in the difference of the refractive indexes of the two layers in the multi-layered mirror, ni and di are the refractive index and the total thickness of the organic compound and the transparent conductive layer, and .theta. is the angle of the light incident on an interface between organic compound layers or between an organic compound layer and a transparent conductive layer, with respect to the normal to the interface, wherein the optical length L is 1.5 times a required emission wavelength, and wherein the required emission wavelength is in a range from (.lambda.m-10) nm to (.lambda.m-50) nm.