Quantitative evaluation of bending reliability for a flexible near-field communication tag

Abstract

Flexible electronic devices under repetitive use inevitably entail damage accumulation that can cause failures in the components and interconnects. The main aim of this study involves proposing test procedures and corresponding testers that can be used to systematically evaluate the bending reliability of flexible electronic devices. In contrast to conventional bending test techniques based on a collapsing radius method, in the present study, the flexible devices were wrapped onto a roller to ensure a constant strain. An example of a near-field communication tag for smart phones was examined to verify the proposed test methods and testers. The results indicated that the critical curvature for cyclic failure was significantly lower than the static critical curvature. Curvature-life diagrams as evaluated by the proposed test method revealed that bending radius and alignment methods significantly affected the reliability of the tags. Thus, the curvature-life diagrams can be used to design a roller radius based on a predefined product life.