| abstract |
A light source comprises an organic light emitting device which emits radiation having a first spectrum and a phosphor layer which absorbs a portion of the light emitted by the organic light emitting layer and which emits light having a second spectrum. The phosphor layer typically absorbs less than all of the light emitted by the organic light emitting layer and typically covers the entire organic light emitting device. The light emitted by the organic light emitting layer is mixed with the light emitted by the phosphor layer to produce light having a third spectrum. Exemplary embodiments of the invention provide advantages over known devices. For example, because a phosphor layer is provided, the light emitted from the organic light emitting device is scattered, which provides improved uniformity in light output over the area of the light source. Also, because most phosphors are relatively stable over time, the light source has good color stability over time. |