Holographic pattern measuring system and its application to deformation analysis of printed circuit board due to heat of mounted parts

A new measuring system, holographic pattern measuring system (HPMS), was developed which is composed of both techniques of holographic interferometry and graphic image processing, and applied to deformation analysis of the printed circuit board (PCB) due to heat of mounted parts. The HPMS was applied to obtain the three-dimensional graphic image pattern of the deformation of-the PCB due to thermal stress with an error of 0.1 /spl mu/m. In addition, the thermographic pattern was obtained by using a thermography system, and a comparison was made of the fringe pattern (holographic pattern) obtained by the HPMS and the thermographic pattern of the PCB surface due to thermal stress. We found that the holographic pattern was different from the thermographic pattern. The results showed that it was difficult to estimate the thermal deformation of the PCB from the thermographic pattern.<
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