The Study Of White Light LED Packaging Technology

Because the light emitting diode (LED) itself has the advantages of lowpower consumption, high brightness, long life, good stability, light weight andso on, the white LED gets a lot of applications: Solid-state-lighting,information display, as a back-light source, flashlight, landscape lighting,mobile phone, television and even automotive fields. LED in optical area iseverywhere, especially in the aspect of lighting, highlighting its strongpointof energy-saving, Pollution-free. LED solid-state-lighting to replacetraditional lighting has become a global trend. Therefore it has importantsignificance in research and improvement of LED performance.White light LED can be achieved through a variety of means, which aremainly divided into three types: light conversion type, mixed type andmultiple quantum type. The paper focuses on the first two types to study,adopting two combinations of chip and fluorescent powder. the first one isblue-chip+yellow phosphor, the paper introduced the Monte Carlo raytracing method to get the luminous flux and radiation power of the high-powerLED using different curvature lens and phosphor layer in different position ofthe cup. The simulation results show that, for the package devices using lenson top of the reflector cup, the curvature of the lens, phosphor layer’s position,and particle size plays an important part in luminous flux extracting andphosphor conversion efficiency. When flat phosphor layer in differentposition, the gap of luminous flux can get to over50percent and the radiationpower also has an obvious difference. When the top-distance between the lensand reflector cup is half of the radius of the cup opening, it can obtain a betterluminous flux output and phosphor conversion efficiency with the position ofthe phosphor layer being around200um below the middle of the cup. thesecond combination is three chips+various phosphors, it adopted MonteCarlo ray-tracing method, through " light-conversion" and" multicolormixing" technologies to get simulated and optimized parameters of white light including Color Rendering Index(CRI),Correlated Color Temperature(CCT),flux, radiation power and phosphor particle density. By adjusting the set ofthree LED chips(red, green and blue),the mixing way of the differentphosphors (red, green, and yellow) and the density of the phosphors, a highCRI white light LED in different CCT under the condition that the amount oflight output including Flux and Radiation power is acceptable was obtained. Itcomes to a conclusion that we should choose the combination of BBB chip+green、red phosphors, BBB chip+yellow、red phosphors and RBB chip+yellow phosphor respectively for cool, neutral and warm correlated colortemperature. Then at last the feasibility is confirmed by experiment.The paper adopted some optical theories to establish the geometric modeland phosphor model. This can be a reference for the research of similarrelated products in future.