Optical skin: Sensor-integration-free multimodal flexible sensing

TL;DR

This paper introduces an optical interference-based multimodal sensing method that enables large-area, sensor-integration-free detection of multiple stimuli with high resolution, adaptable to various applications like human-machine interfaces.

Contribution

It presents a novel optical sensing approach that encodes multiple stimuli as spatial patterns, eliminating the need for complex sensor integration and enabling flexible, high-resolution multimodal sensing.

Findings

Simultaneous sensing of force, temperature, and contact location achieved with a single soft material.

High spatial resolution of tens of micrometers allows shape identification of contact objects.

Demonstrated application in a human-machine interface with a soft haptic device.

Abstract

The biological skin enables animals to sense various stimuli. Extensive efforts have been made recently to develop smart skin-like sensors to extend the capabilities of biological skins; however, simultaneous sensing of several types of stimuli in a large area remains challenging because this requires large-scale sensor integration with numerous wire connections. We propose a simple, highly sensitive, and multimodal sensing approach, which does not require integrating multiple sensors. The proposed approach is based on an optical interference technique, which can encode the information of various stimuli as a spatial pattern. In contrast to the existing approach, the proposed approach, combined with a deep neural network, enables us to freely select the sensing mode according to our purpose. As a key example, we demonstrate simultaneous sensing mode of three different physical quantities, contact force, contact location, and temperature, using a single soft material without requiring complex integration. Another unique property of the proposed approach is spatially continuous sensing with ultrahigh resolution of few tens of micrometers, which enables identifying the shape of the object in contact. Furthermore, we present a haptic soft device for a human-machine interface. The proposed approach encourages the development of high-performance optical skins.