Research Of The Birefringence Measurement System And Improvement

The technique and method of optical measurement has undergone fundamental changeswith the speedy development of electron,laser and automation techniques.For instance,theintroduction of advanced technology of photoelectric reception, digital display,modular circuitand program design greatly boosts the accuracy and efficiency of optical measurementinstrument, opening up the path for the development of precise optical measurement system.Yetas one of the most important properties,the birefringence of wave plate will have a direct orindirect influence on the quality of the precise optical measurement instrument as well as thelaser polarization,etc.Therefore,it is of great significance to evaluate the wave plate through thedirect measurement of birefringence.Based on the principle of electro-optical modulation,SZY-1optical birefringence tester is designed to measure the phase retardation of wave-plate.To the problems of low accuracy caused by non-automatization and the aging system inSZY-1birefringence tester,this thesis,combining the thought of circuit modularization andprogram control,investigates and designs an intelligentized birefringence measurement techniquewhich can adapt to wave plate and make accurate measurement.Considering the practicabilityand commodification of measuring system,the author mainly explores how to improve theaccuracy of measurement as well as the modularization and auto-control of the system based onthe reality of situation and the accumulation of technologies(for instance,the making of waveplates,optical laser system and birefringence test,etc.).In regard to the drawbacks of measuringsystem:difficult positioning of rotating disk and the complexity of operating procedures, thethesis proposes an ideal model that causes the rotating disk to turn with stepping motor forprecise position,thus simplifying the measuring part.To change current situation and after a detailed study of precedent achievements related,this thesis at the beginning of which clarifies the research background,significance and currentstudies on birefringence tester and mainly introduces four advanced tester abroad.Combining theprecedent and relevant knowledge about wave plates,frequency-selective network, photoelectricreceiving conversion and high voltage source,etc.In combination with the principle ofelectro-optic modulation and the technology of program control.Based on STC89C52RC,hardware circuit produces square wave signal via the single-chip computer,controls its phase andthe size of the duly ratio with keys and displays the waveform and value in real time,thusreplacing its original method of phase thick and fine tuning.The former flyback DC high voltageconverter is replaced by the current mode controller UC3842,simplifying high-voltage circuit and making the signal output stable.This paper elaborates the design process of the systematicsoftware and performs test of the altered circuit.The study finds that the testing system fullycorresponds with the original circuit principle,works well and will have a good prospect inapplication.