OUTCOUPLING DEVICE AND LIGHT SOURCE

The invention relates to a light source (1) comprising a light generating unit (2) like an organic light emitting diode and an outcoupling device (3) for coupling light out of the light generating unit in an outcoupling direction (4). The outcoupling device comprises a first region (5) for facing the light generating unit, a second region (7) having a refractive index being smaller than the refractive index of the first region, and a structured intermediate region (6) between the first region and the second region. The first region is optically homogenous and has a thickness in the outcoupling direction being larger than a coherence length of the light, thereby reducing generally possible wavelength dependent interference effects and, thus, a corresponding degradation of the outcoupling efficiency. The outcoupling efficiency can therefore be increased.