High-fidelity and Large-area Flexible Hybrid Sensing System (Invited)

Abstract

Combining printed flexible electronics (FE) with high performance silicon chips, known as flexible hybrid electronics (FHE), can bring together flexible form factors, low-cost fabrications and high computational capabilities, thus enabling more innovations for wearable, artificial skins and IoT applications. However, as a heterogeneous system, motion artifacts and noises pose great challenges on designing robust interfaces between FE and silicon. Besides, the FHE sensing system has to tolerate inadequate device yield, reliability and stability caused by the low temperature process and the large-area nature of flexible sensor arrays. Therefore, it is essential to develop design methodologies for large area sensing applications which can suppress the noises in the interfaces and ensure system robustness without relying on highly reliable devices.To address the noise issue, we prototyped an active electrode (with a thickness ≤2 um), which integrates the electrode with a thin-film transistor (TFT) based amplifier, to effectively suppress motion artifacts. To alleviate the device defects, we proposed an encoder-decoder design which leverages the sparse statistical characteristics of bio-signals via compressed sensing (CS). Specifically, we use flexible circuitry to implement a CS encoder and decode the compressed signal in the silicon side. As a system demonstration, we fabricated the temperature sensor array, shift register and amplifier to illustrate the feasibility of the encoder design using CNT-based flexible thin-film transistors.