A light bulb includes a base, a filament coupled to the base and a cover covering the filament. The filament includes a transparent structure, optoelectronic units arranged on the transparent structure in sequence, each including a side surface, a first and second bonding pad formed on a top side of one of the optoelectronic units, a third and fourth bonding pad formed on a top side of another optoelectronic unit, conductive elements, one of the conductive elements including a bottom surface directly connecting the first and third bonding pads without covering the side surfaces of the one and the another of the optoelectronic units, and a top surface opposite to the bottom surface, the transparent structure continuously covering the optoelectronic units and the conductive elements without directly contacting the top surfaces of the conductive elements, first and seconds terminal electrically connected to the optoelectronic units.