Study On Optical Performance Of High Power LED Chips And Led Lamps

LED (Light Emitting Diodes) as the fourth generation of green lighting source hasreceived more and more attention and research. It has widely used in lamps, indoorlighting, stadiums, car lights and other fields, tending to replace the traditional lightingsource. We need to do the further study of its optical properties, the specific contents areas follows:(1) Based on an optical tracing software, the light extraction efficiency ofconventional LED chips, the flip LED chips and the vertical LED chips are analyzed. Bychanging the material parameters of the semiconductor layers and the chip structure,observe their influence on the light extraction efficiency.(2) The influence of reflector cup and encapsulant of the high-power LED chips onthe light intensity distribution have been detailed analyzed. We changed the shape andthe aperture angle of the reflector, the shape and refractive index of the encapsulant,using the software simulation to obtain the optimized packaging structure.(3) We have designed two kinds of lens using the freeform surface meshingmethod, which could achieve uniform circular spot and collimating function, respectively.The lens can be used as a secondary optics element packaging outside of the LED and itcan also makes integration package of LED for its small volume.(4) We have introduced the photoelectric, color and thermal performance testmethods of LEDs and bulb lamp, and made the high-power LED chips reliabilityexperiments under rapid thermal shock conditions. By recording the changes of therelevant parameters, the failure reasons were analyzed.Through the study of the above four aspects, including the light extractionefficiency of the LED bare chip, the LED packaging optical, the secondary optical design,the chips performance test, made a systematic analysis of the optical properties of LEDchips and lighting, and played a guiding role in the optical design of the chips and lamps.