Laser Gradient Direction And Measurement Device Based On Psd

With high resolution, high sensitivity, fast response speed, location and light intensity simultaneous measurement, PSD is suitable for detector as contactless sensor. We analyse the design of photoelectric digital level based on PSD, and design the laser gradient direction and measurement device based on PSD. The device consists of semiconductor laser, liquid prism, right-angle prism, PSD and its signal processing circuit. The device can realize of accurate measurement or orientation of the level or slight slope, improve efficiency and accuracy of measurement and readjustment.The paper introduces the measuring principle of laser guide and measurement device based on PSD and its composition. Analyse its measuring optical path, and calculate the relationship between the shift of spot on PSD photosensitive surface and installation angle.Analysis of three different schemes of lens collimation system, one is Gauss beam's waist on focal plane, the other one is Gauss beam's waist on target plane, the third is Gauss beam's waist between focal plane and target plane. comprehensive consideration of collimation effect and cost, choose the third one, the collimator distance is 2 times of the Rayleigh distance. In order to get a better collimation effects, this paper uses the defocused telescope alignment system.Based on Fourier-Bessel transformation, diffraction field distribution of Gaussian beam limited by the circular grating is calculated and analyzed.And comparison it with plane wave. It provides theory basis for application of annular grating.