Patent attributes
A light emitting device comprises an excitation source (20), one or more light emitting diode(s) operable to generate excitation light of a first wavelength range (λ1) and a light emitting surface (14) having a phosphor material (26) which absorbs at least a part of the excitation light and emits light of a second wavelength range (λ2), wherein light (32) emitted by the device comprises combined light of the first and second wavelength ranges emitted by the light emitting surface. The device is characterized by the light emitting surface having one or more window areas (28) which does not include a phosphor material and which are substantially transparent to light of the first and second wavelengths. The light emitting surface can comprise a transparent substrate (14) having a pattern of phosphor material on a surface thereof with the one or more window areas evenly distributed over the light emitting surface.
