APPLICATION OF NONDESTRUCTIVE TESTING METHODS TO ELECTRONIC INDUSTRY USING COMPUTER-AIDED OPTICAL METROLOGY

A novel application of NDT to the electronic industry using computer-a ided optical metrology that includes Electronic Speckle Pattern Interf erometer (ESPI), Electronic Shearing Speckle Pattern Interferometer (E SSPI) and Digital Speckle Correlation Method (DSCM) was described. The theoretical analysis based on interferometry and the deformation theo ry was presented and the relationship between fringe-distribution and defect-geometry was given. An important technique-computer-controlled polarization phase shifting-was developed for improving the fringe qua lity and the sensitivity of ESPI and ESSPI. In order to improve the se nsitivity for NDT of small object like electronic elements, a new NDT method using DSCM was first introduced. Two key techniques, the cross- search algorithm and double-lens optical arrangement, were developed t o provide the possibility of high processing speed and small object me asurement. These new techniques will make DSCM the most powerful NDT t ool in electronic engineering. Several applications are presented as e xamples in this paper; they include the electrosound elements, miniatu rized multilayer ceramic capacitor (MLC), compact disk (CD) and optica l fibers. The findings have demonstrated that computer-aided optical m etrology is a powerful tool for NDT applications in electronic enginee ring.