Back to Basics Part 20 - Design Features That Provide Tear Resistance

摘要

Flexibility is the obvious pri-mary benefit of using flexible circuits. This important feature allows for elements of an electronic system to be moved relative to each other either dynamically, such as one might find in a disc drive read-write head or a laptop computer hinge or statically folded into a shape that allows the assembly to be packaged in a smaller volume, which is the most common type of flex circuit application. Without regard to operation and application, all flex circuit designs should be made tear resistant. The reason is that the thin, non-reinforced materials used for flex are vulnerable to tear initiation, which is normally followed quickly by tear propagation and prospective or ultimate failure. However, in spite of the limitations of the material, tear resistance can be improved by employing certain well-established design features in the design. There are actually several possible methods, which are described as follows and illustrated in Figure 1.