US Patent 7834541 OLED device having improved light output

An organic light-emitting diode (OLED) device, comprising: a light-emitting area of an OLED comprising a first electrode, a second transparent electrode, and one or more layers of organic light-emitting material formed between the electrodes; and a light-scattering layer, formed on a side of the transparent electrode opposite the one or more layers of organic light-emitting material, comprising transparent, light-scattering particles, wherein the ratio of the volume of light-scattering particles to the volume of the layer is greater than 0.55 over a majority of the light-emitting area.