The Characteristic Parameters Of The Light-emitting Diodes And Its Testing Technology

This paper introduces an instrument which is applied to measuring the characteristic parameters of light emitting diode's or some of other light sources'. Relevant theories are verified by this instrument.The principle of this instrument system can be described as follows:it takes photodiode as its detector, and a single-chip MCU named AT89C51 is the core processor that manages data acquisition,field control,data communication,etc.PC analyses datas and apply algorithms to get the characteristic parameters of LED,and then gives out the results of analyse in proper ways.This paper consists of six chapters.In the first chapter, the current circumstance of LED industry in the world and the prospect of this industry are described.Here.The measurement of LEDs are emphasised on for it's importance,some of existing methods' defects are enumerated,and then the attention of this dissertion is derived.Chapter two,just gives some characteristic parameters of LED's and the principle of measuring mediods.Chapter three talks about the overall scheme that concerns about the design of the system's architecture and measuring plan. Based on this part,hardware and software is designed.The next chapter four introduces the hardware with dividen functional blocks in details,and applicable mediods dealing with all the functional blocks in hardwre are issued.In chapter five, there are many procedures associated with flow diagrams or codes ,they make the system use easily and effectively.The implement of the user's interfaces , data interfaces and algorithms are expressed here,especially the designing of dealing with anti-noise and communication protocol.The final chapter we summarized the work what has been done in this dissertion , and some results of LEDs' measurent with this instrument are listed(some of them are listed as table in appendix.) .we also point out the shortcomings of the system,and further work is looked forward.