Experimental characterization of polyimide torsional hinges for optical scanner

This paper reports our study results on polyimide hinge characteristics based on direct measurement of its torsional stiffness. Torsional stiffness curves (torque-angular deflection characteristics) with various hinge dimensions were obtained using our preliminary torsional test apparatus. Finite element analysis (FEA), using a multi-load steps static analysis, provided result in good qualitative agreement with experiment. Quantitative disagreement could mainly be attributed to the measurement error and FEA modeling inaccuracy. Frequency response was calculated based on the experimentally obtained stiffness curve, and it was compared with that obtained by experiment using an optical scanner prototype. The results agreed qualitatively, demonstrating that the dynamic behavior can be predicted based on the result from the static torsional test. Although there are remaining issues for accuracy improvement, this experimental torsional test is useful for understanding both static and dynamic behavior of polyimide torsional hinges.