Quantum Physics

On an atomic level when the electrons in an atom of phosphorescent pigment are exposed to photon energy in the form of UV light, (Figure A) they enter an excited state and move into a higher spin state. This Excitation of electrons to a higher state is accompanied with the change of a spin state. (Figure B)

Once in a different spin state, electrons cannot relax into the ground state quickly because the re-emission involves quantum mechanically forbidden energy state transitions. At this point the electrons return to the ground state releasing the stored energy as visible light. As these transitions occur very slowly in VizLite DT, absorbed radiation may be re-emitted at a lower intensity for up to eight hours after the original excitation. (Figure C)

The Strontium Nitrate phosphorescent pigments that are used to produce VizLite DT are formulated to meet our requirements of a quick charge time, a bright “afterglow”, extended “afterglow” period and high laundry performance.

Charging

The following chart shows the different charging times for VizLite DT depending on the light conditions. The light intensity is measured in Lux which is the number of Lumens per square metre.

The amount of light being given off by a particular source, in all directions, is called luminous flux (or “luminous power”) and is a measure of the total perceived power of light.