PCB Designers Notebook: Flexible Circuit Design

摘要

The flexible circuit was originally used as a conductive element for interfacing signals from one elec-tronics assembly to another. Early designs often included nothing more than connectors at each end of the circuit. As surface mount devices became more available, companies began adding electronic functionality to the circuit. As far as attachment methods for surface mount devices, conductive adhesives can be used, but the soldering process most often is used for attaching devices to the copper circuit pattern. Depending on the assembly process, base material selection can be critical. While conductive adhesive and single-point soldering can be applied to polyester films, the dielectric material favored as a base for mass reflow soldering surface mount devices is polyimide film. Polyimide holds up better when exposed to the high temperatures needed to melt solder and complete the joining process.