Interface Structure Of LED Composite Planar Illuminating Sources And Photosynthetic Photon Flux Density

Composite planar illuminating sources of LEDs consist of a variety of interfacestructure，which has an high impact on the light-emission efficiency of lamp. The paperreports the source with photosynthsis active spectra (PAS), which is composed of blue-LEDSand red-emission phorshor.To meet the lighting quality requirements of light sources appliedin planting lighting, the intensity of emission with a660nm-emission is specially designatedas photosynthetic photon flux density (PPFD) is investigated. Fort his purpose, we study theeffects of material component, particle size distribution and interface design on PPFD. Inparticular, high temperature microwave (MW) synthesis procedure was employed to obtainphase-pure,blue-green excitable, efficient CaS:Eu2+phosphor particles. The interfacesrelevant to the single-particle and dispersion medium, the interface between phosphor layerand the substrate and the interface among phosphor layer were focused on. The mainachievements obtained are:A. By applying MW energy, the phase-pure CaS:Eu2+phosphor was successfullyobtained from the single precursor CaSO4in the absence of any extra elemental sulphur andcarbon addition. The parameters of MW power on the decomposition reaction was optimizedand the interaction between electromagnetic and solid particles plays key role to controlheating process and the reaction involved in the formation of pure host phase innon-equlibrium reaction thermodynamics..B. The effect and its mechanism were studied by comparing luminous properties ofsamples prepared by nano-milling and sieving methods. Agglomeration degree of phosphorparticles was significantly reduced by sieving without changing the size of single-particle.The surface defects maybe reduced by milder nano-milling, while the average size of particlesdecreases with the extending nano-milling time.C. The planar illuminating sources with CaS: Eu2+phosphor particles weremanufactured. The emission spectra were measured o be located at red spectrum range uponblue irradiation that can be used to construct photosynthesis active spectrum (PAS). Themodel of Lambert-Beer was applied to describe the light propagating behavior in the interfacebetween single-particle and dispersion medium. Kubelka-Munk’s theory was introduced toanalysis quantitatively the reflection and absorption of light in micron-sized structures.D. By fully taking account of sensitivity to human being’s eye and pigments in plant,conversion among photometric system, light quantum system, irradiation system wasestablished. Calculations for PPFD through irradiance intensity, and irradiance throughluminescent intensity were achieved. The light quantum system was proposed to evaluate theas-mentioned illumination sources.