One failure analysis of switching filter

According to the phenomenon that inside solder joints and adjacent Gold-plated layer surface of the switching filter vary their normal color on a massive scale, the author analyzes the different micro-area of the switching filter with scanning electron microscope (SEM) and X-ray energy dispersive spectrometer(EDS) to find out the reasons. The results show that the contaminants which cause the discoloration come from the organic absorbing material coated inside the switch filter cover.