Holographic pattern measuring system (HPMS) which has been developed by the authors as applied to measure a thermal deformation of contact spring due to current flow. As the results of investigations, a microscopical rolling of contact point was clarified and a relationship between the changing spring shape and the contact voltage was qualitatively mode clear.

A holographic pattern measuring method which combines both techniques of holography and graphic image processing was developed. As a typical application, this method was applied for the analysis of thermal distortion of a printed circuit board (PCB) due to current flow through a point contact, and quantitative thermal distortion pattern of the PCB was obtained.