Research On Micro-testing In Transmission Field Based On Deflectometry Method

Rapid development of micro-nano technology has promoted the wide application of various micro components in different industries,and the growing demand of measurement technology also accelerates the upgrading of various micro three-dimensional measurement methods.In this dissertation,the phase measuring deflectometry(PMD)which is classified into optical measurement method is extended to the micro-testing in transmission field.Providing a feasible method which owns the advantages such as simple structure,low cost,non-contact,non-destructive testing.This micro-testing provides a feasible method for the high-precision transmitted micro testing,such as the local feature area testing of samples or the micro-lens testing.The geometric errors as well as system error in the off-axis structure are analyzed in detail.The main research contents are summarized as follows:The significance of micro-nano structure devices in the advanced manufacturing field of modern science and technology has been demonstrated.After a review over the mainstream measurement methods of micro-nano structure device surface topography,the application status of optical deflection method in the field of micronano device surface topography measurement is expounded as well.And the necessity of the research on micro-testing in transmission field based on PMD is proposed.The measurement principle of the proposed method is introduced.With the aided of the ray tracing of the emit light from illuminate pixel on the projection screen,the transmitted field micro-testing based on deflectometry is realized according to the actual wavefront acquired from the phase-shifting technology and the reference wavefront acquired from the “null” testing system.The phase-shifting technology null testing and wavefront reconstruction technique are expounded in detail in order to explain the principle of proposed method.The main geometric error in transmitted field micro-testing based on deflectometry is studied respectively.Besides,corresponding simulations are performed in order to demonstrate the influence of different geometry error to the aberration in the testing results.The calibration technique of micro-testing in transmission field is conducted.The distortion calibration of CCD camera is executed to complete accurate calibration of the collected images;the spectrometer is put into the calibration of emitted light wavelength of display so as to provide guidance for other experimental device selection,such as the microscope objective;the display deformation and the thickness of the LCD screen are calibrated to realize an accurate calculation of each pixel position.The experimental platform of micro-testing in transmitted field based on deflectometry is set up.Moreover,the verification of feasibility and effectiveness about proposed testing method is achieved according to corresponding micro-testing of characteristic area of scratched optical window and characteristic area of industrial lens,in which the root mean square value of the scratched optical window is 0.0923?m,and the peak to valley value is 3.6067 ?m,.