Machine Vision Assisted Precision Alignment System for Optical Path Calibration in Point Diffraction Interferometer | Chapter 2 | Techniques and Innovation in Engineering Research Vol. 5

 In point dissemination interferometer (PDI), alignment error 'tween objective convergent spot and diffraction small hole made by stab is inevitable during the tests. This wonder will affect the performance of PDI in attend aspects: 1) great wavefront wrong; 2) reduction on diffraction adeptness; 3) quality of interferograms. All these factors can finally reduce the measurement accuracy of the instrument. Aimed at these technical challenges, we intend machine vision helped precision alignment arrangement for PDI optical path measurement. Firstly, Rayleigh-Sommerfeld vector diffraction belief is used to build mathematical model among adjustment error, diffraction wavefront wrong, numerical aperture, and hole size. To satisfy the necessity of error calibration, blueprint of machine vision helped optical path adjustment system is designed. Then we select magnetron sputtering and electron beam lithography to cloth precision diffraction pinhole. In this stage, adjustment images as well as PDI dissemination efficiency (intensities ratio middle from two points reflected and diffracted beam) are the dominant news to determine alignment mistake in multi-directions. In addition, specialized concept processing algorithm is created that can measure alignment error in pel and physical scope. To accomplish automatic correction, numerical model between measurement and control quantities is built. Finally, implementation and experiment of this form are also introduced. Misalignment on sideways translation (XOY plane), longitudinal defocus (unobstructed path Z) and tilt error (XY tile) are well calibrated and the character of interferograms is also improved. It maybe concluded that the proposed scheme has advantages in accuracy and adeptness of optical path adjustment.

Author(s) Details:

Zhuo Zhao,
State Key Laboratory for Manufacturing System Engineering, Xi’an Jiaotong University, No.99 Yanxiang Road, Xi’an-710054, Shaanxi, China, State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun-130033, China and Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi’an Jiaotong University, China.

Bing Li,
State Key Laboratory for Manufacturing System Engineering, Xi’an Jiaotong University, No.99 Yanxiang Road, Xi’an-710054, Shaanxi, China.

Leqi Geng,
State Key Laboratory for Manufacturing System Engineering, Xi’an Jiaotong University, No.99 Yanxiang Road, Xi’an-710054, Shaanxi, China.

Jiasheng Lu,
State Key Laboratory for Manufacturing System Engineering, Xi’an Jiaotong University, No.99 Yanxiang Road, Xi’an-710054, Shaanxi, China.

Zheng Wang,
Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi’an Jiaotong University, China.

Please see the link here: https://stm.bookpi.org/TAIER-V5/article/view/9735