Study Of Particle Measurement With New Type CMOS By Light Scattering

The character of powder is determined mostly by the parameter of particle size and particle shape, etc. So the technique of measuring the particle size distribution (PSD) and describing the particle shape is very important. With the many technique of PSD, light scattering is one of the most popular methods. The paper build up a simulation system, which based on light forward scattering theory of Fraunholf and Mie, and a experiment system, which based on the new type detector of CMOS.With the computer numerical simulations, it is proved that Chahine iterative scheme is effect to PSD. but the error tolerance of Chahine iterative scheme is very small when using it to calculate the equation of Mie's theory. The main reason is the anisomerous distribution of the light energy error on the detector. This paper provided a regularizing operator referring to the inversion method of math to the ill-posed problem and Hirleman's theory. It is proved the inversion of Mie' theory can get a more accurate resolution by the regularizing idea.As to a laser light sizer, this paper discussed the measurement range and tried to get the judge index of the range of it. The judge index is attained from the product of the powder's uniformity index which is submitted to RRB distributing and the mass percentage of particles which extend the detector range. The lower of the index, the more exact the result of the laser sizer.The classical Mie theory is the first fredholm function, and it is a improperly-posed problem, which cann't get a accurate resolution of PSD through increasing the ring number of detector.The PSD is obtained through deconvolution of the average light intensities received from a number of scans. This signal processing is not sensitive to few remnant large particles, which lie outside the required size distribution. For obtain the signal of the large particles and increase the resolution of laser sizer, we provided a discrete measurement method. This discrete method isfeasible proved by the simulations and test.The experiment result shows that Fuga 15d CMOS is well with PSD. The excellent character not only can void the narrow dynamic range of light intensity of CCD, but also can apply to the particle shape measurement.The simulation and measurement system build up with Delphi and Matlab has some excellent performance, such as humanistic operation interface, convenient report making and short calculation time. The fact shows that the simulation and measurement system is reliable.