Reliability Research Of LED Road Lamp Design Technology

High-power LED is a model of semi-conductive diodes. LED is the abbreviationof ‘Light Emitting Diode’. As a new cold-solid lighting source, because of its highlight emitting efficiency, long life-span, energy saving ability and environmentprotectiveness, the semi-illumination-technology using LED as its kernel is thought tobe the one that will replace the traditional incandescent lamp as a new generation oflighting technology in the21st century. As in China, approximately about12per-centof new generated electric power is consumed in the way of lighting each year.Because of its energy saving advantage, if it can be successfully used in the lightingarea, its energy saving potential will be huge.With the purpose of finding out the reliability influencing factors and improvingthe LED road lamp reliability design level, this thesis takes LED road lamp as itsresearch target. Using basic theories and basic methods of reliability research,combined with reasonable analysis of experiments data, it researched the reliability ofpower-LED road lamps. The main works of the paper can be summarized asfollowing:Firstly it gives a introduction of semi-conductive diode’s structure and its photonemitting mechanism, the technical process of LED chip’s manufacture and package,the inner structure of power-LED and how to let a LED emit white light. It alsointroduced the composition of power-LED road lamps, its advantages and especiallyits reliability problems. At the end of the first part, the present research progress ofdomestic and international institutes and the significance and main works of thisthesis are reviewed.The second unit of this thesis mainly contains the following works: The basictheory of reliability, models of series connection, parallel connection, and series-parallel connection are introduced; The sub-systems of driver, LED series andheat radiation are analyzed, and the relation between sub-system and main-system isdiscussed; The definition of LED road lamp is brought up; The main failuremechanisms of LED road lamp are analyzed; At the end of this unit, it gives outdifferent formulas of lamps with different driving models.The third part of this thesis mainly contains the following segments: it analyzesthe light-attenuation data in OSRAM’s LM-80report for high-power LEDs in matlab,and the two light-attenuating models, exponent and linear, are comparativelyresearched; through analysis of light-attenuation data under temperature and electricstresses, the ALE(accelerated life experiment) models of Arrhenius,Single-Stress-Eyring and Multi-Sress-Eyring are calculated; by using matlab’s normaltest commands, the life data samples are statistically analyzed; the life distribution ofLED is researched and its GF(goodness of fit) is also calculated; the end of this partgives the calculation of a specific LED-serial based on the system model seriallycomposed of normal life distributional components.The fourth part of this thesis designs a passive heat radiation transporting path.Through special designs of lamp shell and heat radiation plates, the hear air flowingpath is scientifically arranged. Through these optimizations, the heated air around theheat radiation plates can be transported out of the lamp effectively even when it isunder no-air-flowing condition. Being built inside, the driver and the heat radiationplates can also be properly protected.Finally, the structure and the functions of a LED Lamp are analyzed and the FaultTree of LED Lamp Unity is established. All the Bottom Sets are found out by usingtop-to-sub-to-basic method. The Least Cut Sets of the system are found out throughAscending method and Descending method, and the system failure formula is alsogiven out.