The Development Of Laser Displacement Sensor With PSD

Laser triangulation plays a very important role in the field of modern industry testing as a non-contacted measurement. A laser displacement sensor which based on the laser triangulation principle is developed in this project, with work range of 50±10mm. In this paper, the designing of laser triangulation's optical system, the self-designing of the one-dimensional PSD weak signal detection circuit and the nonlinear compensation of the measurement results have been successfully completed. The main contents and works of this thesis are summarized as follow:(1) With a better understanding of the research background, the latest domestic & overseas technology is analyzed, and the overall plan for this project is formulated.(2) According to the optical characteristics of Laser Diode and the ideal imaging conditions based on triangulation, we use the method of system division to design the whole light path, which gets excellent exit spot and good imaging matched the Scheimpflug's condition.(3) The LD driver circuit with feedback system is designed to get stabilized light source. And signal processing system for PSD is designed according to the feature of output current. This system not only accomplished the task of resisting noise, extracting and magnifying the effective signal, but also adds the light-indicated circuit.(4) The device assemblage is taken after finishing designing work, which involves the installation and fixing of the semiconductor laser, optimization design of the circuit parameters and choice of the lens'best position.(5) System calibration is taken with the linear grating sensor. The resource of main error and corresponding solution is discussed. In order to compensate the non linear error, regression analysis method combined with the relationship of the objective and image distance is adopted.