Abstract. Strain gauges based on polyimide carrier foils and piezoresistive
granular thin films are highly sensitive to strain. Unlike
conventional metal foil, granular film strain gauges also have
a pronounced sensitivity to strain acting in the transverse
direction. A novel method that allows for the modification of the strain transfer is
proposed and proven experimentally. The method is based on the
creation of stand-alone polyimide paths, on top of which the
piezoresistive thin film is located. In this way, the granular film
hardly receives any transverse strain; hence, the transverse
sensitivity is drastically reduced. A picosecond laser system can be
used for both patterning of the thin film and for controlled ablation
of polyimide in order to generate well-defined high path
structures. The working principle of the method is demonstrated by
simulation, followed by an experimental verification using measurements
of the transverse gauge factor. Furthermore, the output signal of
force transducers may be increased using granular thin film strain
gauges of reduced transverse sensitivity.
Novel method to reduce the transverse sensitivity of granular thin film strain gauges by modification of strain transfer
