Analysis of luminance and duration of luminous powder

rare earth photoluminescent pigment because of its long-lasting, non-radiation characteristics are more and more accepted by the industry and customers, but about the rare earth luminescent pigments brightness problems are often puzzled in new customers, the manufacturers say can clearly lit 10 hours, how a few hours out of sight, might think of a lie is not a manufacturer or product quality problems, which may cause some unnecessary misunderstanding. In this pair of glow in the dark pigment brightness duration do simple resolution.
Typically photo luminescent pigment brightness of the unit is cd/m2 (candela per square meter), while the luminous brightness is generally mcd/m2 (milli candela per square meter), we compare the brightness of the light on the common glance.
The midday sun reaches 1 to 100,000 cd/m2,
Day general indoor only 1000 ~ 5000cd/m2,
And our night lights generally 100 ~ 1000cd/m2,
Emergency lights brightness requirements greater than 50cd/m2,
The new electroluminescent signs, luminance only 20 ~ 100cd/m2,
High brightness LED signs made of phosphorescent pigment does not exceed 10cd/m2, and the excitation light source is stopped the moment, the brightness is only two minutes after 1 ~ 2cd/m2, generally 0.060 ~ 0.0990cd one hour / m2, ten hours after General 0.006 ~ 0.010cd/m2. Therefore, the observed brightness of photoluminescent pigments during the day, due to the presence of ambient light (even in the darker dark room, will be more than 1cd/m2), but due to the strong contrast of our outdoor room, eyes feel very dark, and the environment observed, glow in dark pigment is often observed in less than an hour or so to shine. If you use a dark drawer or paper tube to observe what, then more than 10 minutes can not see the glow in the dark pigment shine. So why the production of luminescent pigment manufacturers say can shine 10 hours of it, because the human eye under dark conditions can be observed in the full light is very weak as 0.00032cd/m2, but usually phosphorescent pigment to the brightness of the light attenuation below time can reach more than 10,000 minutes, which means you can continue to light 10,000 minutes (166.67 hours) theory the human eye can see. In order to explain the brightness of the image of luminous pigment, photoluminescent pigment in the early promotion of the time, said to be emitting 8 hours 10 hours, etc., and usually only last a luminous glow pigment ZnS distinguish one hour or less open.
In order to accurately express the universal application and test equipment, and now gradually replaced by one hour data, due to the larger cd/m2 units, so luminescent pigments usually mcd/m2 (milli candela per square meter), generally one hour brightness are between 10 ~ 100mcd/m2, different levels of granularity and brightness are not the same product, the greater the higher the brightness because the luminous particle size, particle size but big bad performance, so in the same light conditions, the more granularity little more upscale products, and of course the price is more expensive, in order to save material costs, usually coarser product selection to achieve high brightness products under the process conditions allow.
Photoluminescent powder from the use of point of view, no need usually 8-10 hours lighting time, fire requires 90-120 minutes. But under dark ambient conditions, at 8-10 hours, or even longer, the human eye can perceive the luminous powder is still weak, and play a role in the lighting instructions. The reason why the rare earth glow in the dark powder called photoluminescent pigment, is as mentioned above, is less than one hour of continuous light-emitting ZnS glow pigments (short-acting glow powder) to distinguish.