Study On The Scanning Collection And Data Processing Technique Of Confocal Detection System

With the development of microelectronics, micromechanics and micro-optics technologies, it is in urgent need of the three dimensional and non-invasive precision measurements of macro and micro composite structure specimens. Therefore, this paper studied the capability of optical tomography and high lateral resolution confocal scanning detection technology, especially analyzed the critical technical problems of the scanning mechanism, data acquisition and data processing algorithms in the confocal scanning detection system.The subject"study on the scanning collection and data processing technique of confocal detection system"mainly includes the following work:(1) In view of the geometric characteristic parameters of macro and micro composite structure specimens, a three dimensional scanning structure has been established in the confocal scanning detection system, which used the stepper motor with micrometer resolution and PZT with nanometer resolution to achieve this function. Further, the non-overlapping effect between the three-dimensional coordinates of stepper motor and PZT, has been analyzed primarily and corresponding adjustment and calibration have been designed.(2) Considering the performance analysis of photodiodes, avalanche photodiode and photomultiplier tube, combined with the characteristics of scanning speed and signal strength in the existing confocal scanning system, the photoelectric conversion module was designed and experiments were conducted to measure the typical parameters, finally the data collection function was realized.(3) A completed software for confocal measurement has been programmed based on LabVIEW, which realizes the computer control of PZT and stepper motor, simultaneously triggered data acquisition and the three dimensional display of measurement results, etc.(4) According to the characteristics of confocal detection system, the false peaks removed filter algorithm was designed, using the two-dimensional correlation operation to achieve sub-regional splicing. A standard grating with 3μm in cycle and 500nm in height was measured and the data filtering was conducted, finally, the measurement error was 0.07μm and 17nm, respectively. The 9 sub-region splicing measurement for micro-accelerometer was carried out and the measurement area was 220μm×220μm, which could further expand the splicing scope.