A light-emitting diode, LED, filament comprising: an elongated substrate ; a plurality of light-emitting diodes, LEDs, mechanically coupled to the substrate; an at least in part light-transmissive encapsulation encapsulating the plurality of LEDs and at least partially encapsulating the substrate; and a plurality of at least partially light-reflective particles arranged on an outer surface of the encapsulation, wherein a particle of said at least partially light-reflective particles comprises: a first face lying against the encapsulation, and a second face opposite to the first face, said second face facing away from the encapsulation, characterised in that a particle of the at least partially light-reflective particles has at least one flat surface and is further characterised by a long dimension length (L1), a short dimension length (L2), and a further long dimension length (L3) and, wherein a first aspect ratio between the long dimension length and the short dimension length, AR1=L1/L2, is in the range 10-300, wherein a second aspect ratio between the further long length and the short dimension length, AR2 = L3/L2, is in the range 10-300 and wherein a third aspect ratio between the long dimension length and the further long dimension length, AR3 = L1/L3, is in the range 0.3-3. an elongated substrate ; a plurality of light-emitting diodes, LEDs, mechanically coupled to the substrate; an at least in part light-transmissive encapsulation encapsulating the plurality of LEDs and at least partially encapsulating the substrate; and a plurality of at least partially light-reflective particles arranged on an outer surface of the encapsulation, wherein a particle of said at least partially light-reflective particles comprises: a first face lying against the encapsulation, and a second face opposite to the first face, said second face facing away from the encapsulation, characterised in that a particle of the at least partially light-reflective particles has at least one flat surface and is further characterised by a long dimension length (L1), a short dimension length (L2), and a further long dimension length (L3) and, wherein a first aspect ratio between the long dimension length and the short dimension length, AR1=L1/L2, is in the range 10-300, wherein a second aspect ratio between the further long length and the short dimension length, AR2 = L3/L2, is in the range 10-300 and wherein a third aspect ratio between the long dimension length and the further long dimension length, AR3 = L1/L3, is in the range 0.3-3. a first face lying against the encapsulation, and a second face opposite to the first face, said second face facing away from the encapsulation, characterised in that a particle of the at least partially light-reflective particles has at least one flat surface and is further characterised by a long dimension length (L1), a short dimension length (L2), and a further long dimension length (L3) and, wherein a first aspect ratio between the long dimension length and the short dimension length, AR1=L1/L2, is in the range 10-300, wherein a second aspect ratio between the further long length and the short dimension length, AR2 = L3/L2, is in the range 10-300 and wherein a third aspect ratio between the long dimension length and the further long dimension length, AR3 = L1/L3, is in the range 0.3-3. <EOS>