Study on large scale form and position errors measurement

A research on measuring form and position deviations of large scale dimension using laser diode, optical fiber and phase plate diffraction alignment technique and a matrix CCD detecting technique was proposed in this paper. The principle of laser alignment using a π step phase plate was analyzed theoretically and calculated using a computer numerically. Also in the paper, the operation principle and signal processing methods of a matrix CCD that used to detect the deviation absolutely were stated. It was emphasized on introducing some of large-scale form and position errors measuring system and the measurement accuracy of these systems are given. The comparing experiment result with HP5528 exhibited that the accuracy of the system coincides with the one of HP5528 in the straightness measurement.