Research Of Intelligent Measurement On LED Photoelectronic Parameter

With the development of application of LED, people require top-quality LED, especially in wavelength and light intensity. The research task include on-line measurement of LED's wavelength and light intensity, then separate automatically according to user's request in order to improve the quality of LED. It has high measurement accuracy, high speed and low cost.Firstly, the theory of photodetector and photoelectric conversion law is detailed introduced. According to discussing the parameters of photodetector, PIN photodiode is used to measure the luminous intensity of LED. As the same time, ICL7650 is selected to amplify the slender signal as it offers exceptionally low input offset voltage and is extremely stable with respect to time and temperature.The technique of multi-channel sprctrum measurement plays an important role in measuring sprctrum parameters of LED, with fast and real-time properties. According to the dispersive theory, LED sprctrum is diffracted by flaming grating and then imaged by linear CCD which is oriented on the focus of lens. With the relationship of scheduling and spatial pixel location, the LED's sprctrum parameters we can be measured onetime.The system is one optics, machine, electricity conjoint complicated system, in which data acquisition is essential to analyze and deal with the data obtained from system. Programs are designed with application to PC and functional hardware by LabVIEW. LabVIEW is a sort of new fashioned instrument software that multitude data acquisition, data analysis and high resolution data display for one-piece, which is based on the graphic virtual instrument.In the last chapter, a great deal of data is analysed which is obtained by the system.The text analyse the dominant error source of the impact system accuracy, including measurement distance, driving current and fixing obliquity in luminous intensity measurement, and theory error in sprctrum parameter measurement. A lot of ameliorate means are proposed in the text at the same time.