A light emitting device comprising: a conductive support member; a first group and a second group, the first group including first light emitting cells (A1 to An) that are connected to each other in series, the second group including second light emitting cells (Bn to B1) that are connected to each other in series, the last light emitting cell (An) of first light emitting cells (A1 to An) being connected in series with the first light emitting cell (Bn) of the second light emitting cells (Bn to B1), and the first light emitting cells and the second light emitting cells (A1 to An, Bn to B1) each including a first conductivity type semiconductor layer, an active layer under the first conductivity type semiconductor layer, and a second conductivity type semiconductor layer under the active layer; a first electrode layer connected to the first conductivity type semiconductor layer of the first light emitting cell of the first light emitting cells (A1 to An); a plurality of second electrode layers (122, 123, 124), each under the second conductivity type semiconductor layer of each one of the first and second light emitting cells (A1, A2, An, Bn, B2) except the last light emitting cell of the second light emitting cells (Bn to B1), a first portion of each second electrode layer being connected to the second conductivity type semiconductor layer of the corresponding light emitting cell (A1, A2, An, Bn, B2) and a second portion of each second electrode layer being connected to the first conductivity type semiconductor layer of a next light emitting cell (A2, An, Bn, B2, B1) connected in series; a third electrode layer disposed under, and connected to, the second conductivity semiconductor layer of the last light emitting cell of the second light emitting cells (Bn to B1); a first electrode connected to the first electrode layer; and an insulating layer (151, 155, 156) around the first to third electrode layers, wherein the second electrode layer connecting in series the last light emitting cell (An) of the first light emitting cells (A1 to An) with the first light emitting cell (Bn) of the second light emitting cells (Bn to B1) also makes contact with the conductive support member, characterized in that the light emitting device further comprises a second electrode connected to the third electrode layer; wherein the first and second electrodes (171,173) are adapted to be connected to a first side of an AC power source and the conductive support member is adapted to be connected to a second side of the AC power source, such that the first light emitting cells (A1 to An) of the first group is operated for a first half operational period of AC power and the second light emitting cells (Bn to B1) of the second group is operated for a second half operational period of the AC power. a conductive support member; a first group and a second group, the first group including first light emitting cells (A1 to An) that are connected to each other in series, the second group including second light emitting cells (Bn to B1) that are connected to each other in series, the last light emitting cell (An) of first light emitting cells (A1 to An) being connected in series with the first light emitting cell (Bn) of the second light emitting cells (Bn to B1), and the first light emitting cells and the second light emitting cells (A1 to An, Bn to B1) each including a first conductivity type semiconductor layer, an active layer under the first conductivity type semiconductor layer, and a second conductivity type semiconductor layer under the active layer; a first electrode layer connected to the first conductivity type semiconductor layer of the first light emitting cell of the first light emitting cells (A1 to An); a plurality of second electrode layers (122, 123, 124), each under the second conductivity type semiconductor layer of each one of the first and second light emitting cells (A1, A2, An, Bn, B2) except the last light emitting cell of the second light emitting cells (Bn to B1), a first portion of each second electrode layer being connected to the second conductivity type semiconductor layer of the corresponding light emitting cell (A1, A2, An, Bn, B2) and a second portion of each second electrode layer being connected to the first conductivity type semiconductor layer of a next light emitting cell (A2, An, Bn, B2, B1) connected in series; a third electrode layer disposed under, and connected to, the second conductivity semiconductor layer of the last light emitting cell of the second light emitting cells (Bn to B1); a first electrode connected to the first electrode layer; and an insulating layer (151, 155, 156) around the first to third electrode layers, wherein the second electrode layer connecting in series the last light emitting cell (An) of the first light emitting cells (A1 to An) with the first light emitting cell (Bn) of the second light emitting cells (Bn to B1) also makes contact with the conductive support member, characterized in that the light emitting device further comprises a second electrode connected to the third electrode layer; wherein the first and second electrodes (171,173) are adapted to be connected to a first side of an AC power source and the conductive support member is adapted to be connected to a second side of the AC power source, such that the first light emitting cells (A1 to An) of the first group is operated for a first half operational period of AC power and the second light emitting cells (Bn to B1) of the second group is operated for a second half operational period of the AC power.