Passive array-type shape-recognition tactile sensor based on mechanoluminescent effect

Tactile sensors possess the capability to detect geometric shapes through direct physical contact without relying on complex data processing algorithms, offering broad application prospects in industrial automation and intelligent manufacturing. However, conventional tactile sensors are often susceptible to electromagnetic interference, which limits their practical utility. To address this issue, we propose a novel passive array-type shape-recognition tactile sensor (SRTS) based on a hemispherical architecture. When the ZnS:Cu@Al 2 O 3 mechanoluminescent material is subjected to external force, mechanical stimulation is converted into an optical signal. Leveraging this luminescent property, we designed and fabricated a 3 × 3 sensing array composed of hemispherical structures with different radii. While enhancing the sensitivity of the mechanoluminescent signal, the system exploits the strain-response characteristics of individual hemispherical structures and the signal variations induced by changes in the distance between the hemispherical structure and the microsphere probe tip, thereby enabling effective recognition of the geometric shape of contacting objects. On this basis, we further derived a force–optical coupling model to correlate the output light intensity with the applied force. The SRTS demonstrates excellent pressure-sensing performance, with a loading response time of 110 ms and an unloading response time of 90 ms, along with good stability and durability. Moreover, the array architecture can be flexibly scaled to meet the requirements of various practical application scenarios. This study not only extends the application boundaries of mechanoluminescent materials in tactile perception but also provides new perspectives and design strategies for future implementations in photonic skin and robotic tactile sensing.