Fabrication and characterization of a phosphor based photon conversion film

In this paper, morphological, structural, optical properties of phosphor and the phosphor based photon conversion films (pb-pc films) were studied. The overall performance of a pb-pc film was determined by the properties of the phosphor and matrix materials as well as their interaction. A quantitative relationship between the performance and the microstructure of the film which consists of CaS:Eu as phosphor and silicone as matrix material were investigated. A mathematical model was also proposed to describe the relationship of the optical properties of the phosphor composite films and their compositions. The simulated spectrum based on the mathematical model is found in good agreement with the one measured experimentally. The transmittance of the phosphor films decreases gradually with the phosphor concentration increases in the film. The CaS:Eu phosphor film can increase the color rendering index (CRI) Ra of the blue LED chips packaged with YAG:Ce phosphor film, the biggest Ra value is 90.9 when 25 wt% CaS:Eu phosphor film is used, indicating that the Ra value has increased 14% than the one without CaS:Eu phosphor film.