A filament includes a radiation-transmissive substrate, a plurality of light emitting diodes and a converter layer, wherein the substrate has an upper side and a lower side facing away from the upper side, and the LEDs are arranged on the upper side of the substrate, the converter layer covers the LEDs, the upper side and the lower side of the substrate, and the converter layer has a first sublayer on the upper side and a second sublayer on the lower side, and the converter layer is configured to obtain an improved radiation profile of the filament such that the converter layer has a varying vertical layer thickness along a lateral direction, and/or the first sublayer and the second sublayer differ from one another in their geometry and/or material composition.