High-Resolution Optical Three-Axis Tactile Microsensor Based on III-Nitride Devices With Integrated PDMS Bumps

In this letter, an optical three-axis tactile microsensor is fabricated and characterized. Through the monolithic integration design, the chip-scale GaN-based device consisting of one light emitter and four light-detecting units is developed. By incorporating a flexible bump layer, the integrated device with a size of
$1.3\times 1.3\times1.4$
mm
$^{\mathbf {{3}}}$
can effectively respond to the normal and shear forces, demonstrating a high resolution of 2 mN. The developed microsensor features a compact structure, small footprint, high stability, and three-axis high-resolution measurement capability, which makes it suitable for a variety of applications requiring precise force detection.