Development of Elastic Diaphragm Structure for Ultralow Stiffness Probe and Mechanical Properties Testing Method

For the clamping element of the probe, we presented a novel multibeam folded “
${Z}$
” type triple constraint diaphragm, achieving ultralow measurement stiffness and stiffness isotropy through the modification of the flexible structure while improving the compactness of the probe system. Meanwhile, a mechanical model that analyzes the role of different parameters in the structure on the measurement stiffness was developed for the proposed diaphragm, which provides theoretical support for the optimal design of the microprobe. In addition, to verify the performance of the proposed diaphragm, a fiber optic-based force-measuring device (FOFD) was presented, which uses a cantilevered single-mode fiber (SMF) for force measurements, achieving high accuracy and resolution by acquiring incident light by an objective lens and a CCD. Following experimental calibration, the FOFD demonstrates a sensitivity of 1.86 pixel/
$\mu \text{N}$
and a measurement range of 1.2 mN. The proof of concept was fully validated through experiments on the proposed diaphragm using FOFD, where the diaphragm is an excellent compliant mechanism and reduces the contact force when the probe operates at micro-trigger precision. Consequently, these results demonstrate the potential of the proposed multibeam folded “
${Z}$
”-shaped triple constraint diaphragm for accurate probing in microapplications and nanoapplications, as well as the optimized fiber-optic force measurement device providing a more accurate calibration tool for various microforce sensing applications