Phosphor powder, commonly known as luminous powder, is usually divided into two categories: photoinduced energy storage luminous powder and radioactive luminous powder. Photo-induced energy storage luminous powder is a fluorescent powder that stores light energy after being irradiated by natural light, fluorescent light, ultraviolet light, etc., and then slowly releases it in the form of fluorescence after the light irradiation is stopped. Therefore, at night or in the dark , can still see the glow, lasting as long as several hours to ten hours.

Fluorescence is a process that produces light with very little heat compared to thermal radiation. Appropriate materials absorb high-energy radiation and then emit light with photons of lower energy than the excitation radiation. When the luminescent material is solid, the material is often referred to as a phosphor. The high-energy radiation that excites phosphors can be electrons or ions with high velocities, or photons ranging from gamma rays to visible light.