Study On Two Spherical Phosphor And Simulation Of LED Illumination

White light-emitting diodes (WLEDs) are known as the new generation of green lighting, following with the incandescent, energy saving lamps because of its advantage of energy-saving, safe and stable, environment-friendly and long-life. This paper reviewed the development process, emission mechanism, preparation methods and characterization methods of the LEDs. There are some ways to achieve WLEDs:GaInN blue chip excite yellow phosphor, GaInN blue chip excite red and green phosphor; ultraviolet chip excite RGB three-color phosphor; and using a combination of red, green and blue chip emit whitecolor. We compared these methods and concluded that yellow-emitting YAG:Ce3+ fluorescence powders are easy to realize industrial production because of its convenience and low cost. However, currently the most in-need phosphor is red phosphor. To produce one red phosphor with stable luminescent properties and high efficiency will have a great positive effect on light-emitting areas and display areas.In this paper, we prepared YAG:Ce3+by high temperature solid phase method. We characterized the materials by X-ray diffraction (XRD), fluorescence spectroscopy (PL), scanning electron microscopy (SEM) and other testing methods. The result show that we can get YAG:Ce3+ with good optical performance by high temperature solid phase method. The obtained yellow-green YAG:Ce3+ is spherical-morphology, with good crystallinity and single dispersion. We learn the best reaction time through experiment. The YAG:Ce3+ sample in 1500℃ have higher luminous intensity than that in the 1350 ℃. Therefor, high reaction temperature will help to improve the luminescent properties.We prepared CaWO4:Sm3+ by hydrothermal method. We characterized the material properties by X-ray diffraction (XRD), fluorescence spectroscopy (PL), scanning electron microscopy (SEM) and other testing methods. The experiments results indicate that different doping concentrations, reaction time and other conditions will influence the morphologies and luminescent properties of the obtained samples. By the contrast experiments with different doping concentrations, we can learn that when the doping concentration of Sm3+ is 6%, the sample can get the best light-emitting properties, with the scheelite tetragonal structure, good spherical morphology and a red light emission peak at 647nm.Finally we used ZEMAX to simulate the illumination of WLEDs to have a better understanding of the working principle and optical properties of LED.