Fluorescent lamps are filled with mercury. As the working time of the lamp increases, a slight blackening will occur along the entire length of the lamp due to the patterns formed by mercury evaporation. This is a normal phenomenon.
As a result of the sputtering and evaporation of the electronic powder on the electrodes during the lamp starting and ignition process, obvious large diffuse black spots gradually appear on both ends of the lamp, which is the common black circle near the two ends of the lamp. In addition, if the starter is of poor quality and fails to start or causes the lamp to flash frequently, it will also accelerate the lamp to turn black. When the black spots are severe, it indicates that the life of the lamp is about to end.
