Research On Transmitted Wavefront Testing With Large Dynamic Range Based On Deflectometry

Various transmitted elements are important components in modern optical systems,which are applied in the systems ranges from optical to industrial fields.With the improvement of the optical system performance in the frontier high-tech field,high accuracy of transmitted elements testing is required.Transmitted wavefronts testing provides a feasible way for the quantitative evaluation of transmitted elements,in which the achievable dynamic range is the key issue.The deflectometry enables wavefront testing with a simple system set,large dynamic range and high accuracy.In this paper,a computer-aided deflectometry is proposed to achieve accurate testing of transmitted wavefront from various transmitted elements with large dynamic range.The main research contents are as follows:The great contribution of transmitted wavefront testing technology to the modern optical system is discussed.After a review over the current transmitted wavefront testing methods,the necessity of the research on transmitted wavefront testing system based on deflectometry is put forward.A simulation system based on the deflectometry for transmitted wavefront testing is modeled to analyze the feasibility of the proposed transmitted wavefront testing method.The theoretical achievable precision of the proposed method is analyzed,in which the testing precision of a large aberrated wavefront with PV value of 29.8933 ?m and RMS value of 3.6758 ?m reaches 4.5 nm.The geometrical errors of each components in the deflectometric system is studied.A computer-aided system geometry calibration method is proposed to realize the geometrical errors calibration.Besides,calibrations and alignments of camera lens distortion,display emitted light wavelength as well as the deformation of the display are carried out.The total internal reflection(TIR)in the testing of large aberrated transmitted wavefront is analyzed.A TIR data removal method based on system geometry is proposed,and the effect of the proposed method on transmitted wavefront testing result is analyzed in both simulation and experiment.The experimental deflectometric system for transmitted wavefront testing has been established and the transmitted wavefront testing of optical window and an industrial element is carried out.Comparing the wavefront testing result of optical window with the testing result of ZYGO interferometer,testing accuracy as well as the repeatability precision of nanometer are realized.Besides,feasible wavefront testing of large aberrated wavefront with RMS value larger than 30 ?m from the testing industrial element is realized.