Facts about Phosphorescence

What mechanism is used to emit light?

Each crystal of a phosphorescent pigment has electrons in it. These electrons are excited to gradually release energy when they are exposed to ultraviolet rays or other rays that are contained in fluorescent light or natural light and when they return to their original condition (ground state).
Light is emitted when this release of energy is output.

In which applications are phosphorescent pigments used?

Phosphorescent pigments are used in versatile applications including marks and signs, automobiles, railways, aircrafts, building materials, toys and sundry goods where safety factors and design quality are important elements.

Radioactivity was in the news recently. Are phosphorescent pigments safe?

Phosphorescent pigments produced by Nemoto DO NOT contain substances that are hazardous to the human body. Raw materials of high purity and high quality are very carefully selected and the phosphorescent pigments produced by Nemoto are produced at Nemoto’s own plant in Portugal after being developed by its research laboratory in Hiratsuka, southwest of Tokyo, Japan.
Nemoto is very rigorous in implementing quality management and in complying with chemical regulations of the various countries and regions of the world including the RoHS Directive and REACH Regulation. Absolutely no radioactive substances are used.
Please examine Nemoto’s measurement data of radioactivity for the representative grades of its products in the following PDF file. (The PDF file is in Japanese language only at present)

Are phosphorescent pigments produced by digging up rare earth elements deep in the mountains in China?

No, they are not. Phosphorescent pigments are produced by artificial chemical synthesis of several substances including alumina and rare earth elements.

Fluorescence? Phosphorescence?Noctilucence(Glow in the dark)?
What are the differences among them?

As in the fluorescent lamps around us that light up, fluorescence emits light as long as it is excited. Phosphorescent pigments and luminous pigments are officially called “long afterglow phosphors,” “phosphorescence,” etc. They are called “phosphorescent pigments” because they look as if they are storing light and “luminous pigments” also because they look as if they are emitting light during the night.

Why are they so expensive? Can’t they be produced less expensively?

Nemoto supplies its products at the best prices, which includes the cost of product assortment to meet the diverse needs of the customers and the cost of providing aftersales services such as the luminance measurement service.
Our products are not inexpensive, but Nemoto is committed to selling and continually enhancing applications of phosphorescent pigments for the future.