17.3 Hybrid System for Efficient LAE-CMOS Interfacing in Large-Scale Tactile-Sensing Skins via TFT-Based Compressed Sensing

Abstract

Tactile sensing has wide-ranging applications, from intelligent surfaces to advanced robotics. Large-Area Electronics (LAE), based on low-temp. fabrication $(\lt 200 ^{\circ}\mathrm {C})$ of thin films, presents distinct capabilities, due to compatibility with a broad range of materials (enabling diverse transducers), as well as large and flexible substrates and materials-deposition methods (enabling expansive and formfitting sensing arrays). However, low performance/energy-efficiency of LAE thin-film transistors (TFTs) necessitates hybrid systems, integrating Si-CMOS ICs for system functions (sensor readout/control, processing, etc.). Initial work shows that a primary challenge in hybrid systems is the large number of interfaces required between LAE and CMOS, particularly as the number of sensors scales [1], [2]. This paper presents a force-sensing system that exploits signal sparsity exhibited in many large-area tactile-sensing applications (e.g., detecting point damage/stress in structures [3]), to reduce interfacing complexity to the level of sparsity, rather than a level related to the number of sensors (e.g., [1]). This is achieved via compressed sensing (CS), enabling sensor-acquisition by simple switches, readily implemented using TFTs. While CS has previously been leveraged in a hybrid-system architecture targeting signal sampling-rate requirements [2], this system applies it for high spatial resolution in tactile sensing.