The history of photo- luminescent pigment, photoluminescent product

The History of Luminescent Pigments
The evolution of luminescent pigments has passed through four stages. Discovery and Initial Applications: Luminescent material was discovered in 1936. The negative radioactive material Radium was used to yield phosphorescent material. Tritium replaced radium by 1943 due to improved toxicity. Yet the toxicity remained a concerned and commercialization was limited to small quantity applications, primarily watch facings.		Luminescent Watch made by Penerai June 1936

	combined with a zinc sulfide yielded second-generation luminescent material. Yet the luminescent effect weak, brightness low, and duration weak. The pigment still contained radioactive material and toxicity concerned a limitation. In 1994, Philips patented a non-radioactive rare earth luminescent material. The rare earth material could only be found in China. Due to increasing national interest, Chinese research resources were focused upon developing additional 3^rd generation non radioactive and non toxic luminescent products.
These 3^rd generation luminescent pigments had drastically improved performance characteristics. Light absorption in 20-40 minutes (fully charged) delivered light emissions for more than 10 hours. The brightness was 30-50 times stronger than the 2^nd generation phosphorous based materials. The afterglow can typically be recharged multiple times for 30 years. While 3^rd generation luminescent pigments are a significant improvement on previous generations, there remained significant application issues. The 3^rd generation pigments degenerate when exposed to moisture, water, oxygen, strong acids or other harsh chemicals used in today’s production methods.
4^th Generation NLP® New Luminescent Pigment was invented in 2005, yielding improved performance without many of the application problems of prior materials. NLP® is based on alkaline earth aluminates materials group that use europium as an activator. The NLP® pigments are processed under state of the art conditions and technology that significantly increase the luminescent characteristic. The pigment can be fully charged in 40 seconds and give luminescent afterglow up to 16-24 hours. For perspective, the NLP® pigments deliver a brightness that is 150 times stronger than the 2nd generation luminescent pigments. By controlling the molding activities, an enhanced crystalline structure and tighter particle size distribution delivers increased the brightness of the luminescent pigment. Incorporating modern bondering technology and coatings into the molding process protects the NLP pigment to establishing NLP® pigments as truly 4th generation luminescent technology.
NLP® pigments can be used in various production methods. Careful selection of production method can yield a pigment that can endure temperatures up to 900 C before losing its key performance characteristic. Exposure to water, moisture, oxygen, strong acids or heat will not harm the NLP® pigments.. With the 3^rd generation luminescent pigments, production processes needed to be adapted and changed, due to the characteristics of the pigment. Production risks included pigments migrating to the ink and coatings, unreliable plastic end products and other application challenges. Next Generation B.V. has created a protective layer for specific production methods. It has become possible to use NLP© on glass, plastic, coatings, ink, and other materials. By using ceramic and other protection layers, the pigments can undergo high mechanical stress from extrusion in plastics and is protected against harsh acids. Next Generation B.V. has also tightened the distribution of particle size. This reduces mechanical stress during production and carriers can incorporate the pigment easier. By controlling all these characteristics, the brightness was increased and the luminescent effect enhanced and the estimated life span extended to decades. These performance enhancements have been achieved without requiring significantly changed current production methods.