| Particle technology is widely used in the fields of environment,energy,chemical industry and medicine.The accurate measurement of particle size is of great significance to the development of related fields.The method of particle size measurement based on the light scattering(diffraction)principle is characterized by high speed,high precision and without destroying the characteristics of the sample.And the measurement methods based on the principle of small-angle scattering(diffraction)have been widely used.In order to solve the problem of laser particle size measurement using the new type of photoelectric detector device with general linear array and area array,this paper presents a method using cylindrical lens as the particle diffraction receiving lens based on Fresnel diffraction principle.And then,derived and analyzed the diffracted light intensity distribution characteristics,conducted a simulation,and conducted a preliminary experiment.The main work of the dissertation is as follows:1.Based on the analysis of the main methods of particle detection,according to the principle of diffraction,a particle measurement method based on cylindrical lens receiving light signal is proposed.The formula of Fresnel diffraction spectrum of particles under cylindrical lens is deduced.The transformation of the cylindrical lens and the characteristics of the intensity distribution of the particle diffraction were analyzed.2.The phase shift effect of spherical lens and cylindrical lens in diffracted field is simulated by MATLAB software,and the spectrum distribution of particles under the action of two lenses is simulated and compared.3.A beam expanding and collimating system for laser particle size measurement was developed.An experimental system was set up according to the proposed method and an experiment was conducted.At the same time,a reentrant optical path adjustment device for particle absorption spectroscopy was designed and experimentally verified. |
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