Contact Resistance Characteristics of Complex Structure Contacts for Contaminated Printed Circuit Board in SO{sub}2 Environment

摘要

Characteristics of conductive elastomer which is composed of silicone rubber and dispersed carbon black particles shows conductive and elastic properties in one simple material. This material has been widely applied to connectors of liquid crystal panels and contacts of switches. However, since surface state of the contact is very soft, it is difficult to remove contaminant films of contaminated opposite side contact surface and to obtain low contact resistance owing to break the film. This study has been conducted to clear structures of the elastomer which indicates removal characteristics for contaminant films and low contact resistance. As specimens, six different types of the elstomer contacts composed by different type of dispersed such materials as carbon and metal fibers, metal mesh, and plated surfaces were used. The contacts of opposite side were Au and Sn plated contact surface on a printed circuit board (PCB). In order to contaminate contact surfaces of PCB, its surface were subjected to expose SO{sub}2 gas environment. The elastomeric contacts contained hard materials showed lower contact resistance than only dispersed carbon particles in the elastomer matrix for both contaminated PCB contact surfaces.