Optimize Yellow Phosphor Film Structure In The Planar White Lighting System

The dominant way of white planar lighting system is using blue LEDchips to stimulate yellow phosphor film. The phosphor film is made by phosphor andsilicone, and put the phosphor film on the blue chips will generate white lights. Thephosphor film far away from the LED chips will not appear serious efficiency droopand color deviation problem. The phosphor distributes in the film evenly, it willimprove the uniformity of light sources and the color deviation phenomenon isimproved at the same time. The stability of LED sources is ensured. This process ofphosphor technique saves the original packaging of dispensing process, improves theconsistency of production rate and reduces the cost.Although the luminous efficiency of planar lighting system is improved greatly,but the light distribution is not uniform enough, the color temperature on the edgearea of the detector surface is too low, these phenomenon can improved by changingthe structure of the phosphor film, the light efficiency can further improved also. Thesimulation process in this paper is designed in optical design software. The YAGphosphor is the material which simulated in this paper, the characteristics used todefine phosphor properties are excitation spectrum, absorption spectrum, emissionspectrum and quantum efficiency. The Mie theory is used to simulate the process forget an accurate results. The quantum efficiency, scattering coefficient, the anisotropiccoefficient and the concentration of phosphor are obtained by this theory. Finally, theplanar lighting system and phosphor film mold are set up.When the luminous model is built, need to further optimize the luminousefficiency. A kind of phosphor film with etching grooves is designed, this kind ofphosphor film can effectively improving luminous efficiency of the lighting sourceand the color uneven phenomenon. By etching groove structure on edges parts of thephosphor film, the light efficiency increased2.57%, the average illumination poweris58.372w/m2, and the low color temperature at the edge parts is improved. Differentphosphor film surface structures will change the candela distribution of output light.Different candela distribution of output light can applied to different lighting system.The double etching phosphor film is studied further, through the simulation; the double etching phosphor film also can increase the light efficiency. This method doesnot add any extra device, is an easy method for practical application.