Luminescent paint is a paint with luminescent function made of luminescent materials. The luminescent properties mainly depend on the properties of luminescent materials. Different excitation methods are usually used to distinguish various types of luminescence , such as photoluminescence, radioluminescence, thermoluminescence, electroluminescence, and cathodoluminescence.
The phenomenon that the excitation source can continue to emit light after it is stopped or isolated is called afterglow. Those that emit intermittent light with an afterglow time of less than 10-8s are fluorescent materials, and those that emit continuous light with an afterglow time longer than 10-8s are light-storage materials. Self-luminescent materials contain radioactive elements as internal excitation sources.
Luminescent materials usually include matrix materials, activators, sensitizers and cosolvents, etc. Self-luminescent materials should also contain a small amount of radioactive elements as internal excitation sources.
There are two main types of light emitting materials: the first type is called composite light emission, that is, when the electrons are in the excited state, they leave the original light emitting center and enter the conduction band. When the electrons in the conduction band leave the center produce When the holes recombine, they emit light; the second type is called discrete center emission, that is, when the electron is in an excited state, it does not leave the original emission center, but is excited from the ground state to a higher energy level. When an excited state returns to the ground state, energy is released in the form of light.
The prepared luminescent materials are usually not directly used in the preparation of luminescent coatings, because the luminescent materials are generally composed of substances that are afraid of water such as zinc sulfide and calcium sulfide, and usually need to be protectively coated to make luminescent pigments before they can be used. . The luminescent material needs to have a certain volume to emit light. Usually, the luminescent material must not be ground together with the base material.
Luminescent coatings are widely used, such as fluorescent lamps, televisions, radar screens, oscilloscopes and other display screens and display devices, sights for weapons, dials for control and indicating instruments of aircraft and various vehicles , traffic signs and traffic signs Lines, advertisements, sign boards, emergency weak lighting for buildings such as theaters and underground shopping malls , as well as landscaping and decoration of toys and household items.
