There are provided a long persistent phosphor capable of keeping high persistent intensity and white persistence of especially satisfactory color purity after the phosphor is excited by ultraviolet irradiation and then the excited light is cut off, and a fluorescent lamp, a display item of long persistence and a formed product of long persistence in which the phosphor is used.
A long phosphorescence persistent phosphor which comprises a mixture or mutual deposit of the first phosphor emitting long persistence in the first wave range by ultraviolet absorption, which is one or more than two of the following phosphors (i) and (ii), and a second phosphor which is excited by at least a part of emission of the first phosphor.
Magnesium-strontium silicate phosphor (i) prepared by co-activating a complex-oxide containing Sr, Mg and Si as a matrix metal component with Eu and Dy.
Strontium-aluminum silicate phosphor (ii) prepared by co-activating a complex-oxide containing Sr, Al and Si as a matrix metal component with europium Eu and Dy.
The long persistent phosphor is used as a fluorescent screen to prepare a fluorescent lamp, applied to a displaying part to prepare a display item of long persistence or added to plastics and other materials and formed into a desired shape to prepare a formed product.