But this substance is more dangerous. If the cover is broken, it will cause radiation damage to the human body.
Later, some low-radiation materials were used to reduce the danger.
Modern watches have long since stopped using this technology.
The most common method is to use Super-LumiNova. Strontium aluminate is a coating that can absorb light and emit light. It absorbs gamma particles in light and then emits light. It is a long-lasting luminescent material, and will not have the problem of aging and fading.