Abstract: A light emitting device (100) comprises a light source (114) mounted in a housing (112), a lens (122) through which light from the source (114) is emitted from the housing (112), and a filter (126) arranged between the light source (114) and the lens (122) to filter the emitted light, the filter (126) being of dichroic type and the lens (122) being asymmetric. The light emitting device (100) may comprise a plurality of light sources (114) and/or the filter (126) may be adapted to transmit perpendicularly incident light and to at least partially reflect obliquely incident light.