Multifunctional flexible optical waveguide sensor: on the bioinspiration for ultrasensitive sensors development
多功能柔性光波导传感器：超灵敏传感器开发的生物灵感
多機能フレキシブル光導波路センサー：超高感度センサー開発のためのバイオインスピレーションについて
다기능 유연한 광 도파관 센서: 초고감도 센서 개발을 위한 생체 영감
Sensor de guía de onda óptica flexible multifuncional: sobre la bioinspiración para el desarrollo de sensores ultrasensibles
Capteur guide d'onde optique flexible multifonctionnel : sur la bioinspiration pour le développement de capteurs ultrasensibles
Многофункциональный гибкий оптический волноводный датчик: на биоинспирации создания сверхчувствительных сенсоров
Arnaldo Leal-Junior ¹ ², Leticia Avellar ¹, Vitorino Biazi ¹, M. Simone Soares ³, Anselmo Frizera ¹, Carlos Marques ³
¹ Graduate Program in Electrical Engineering, Federal University of Espírito Santo (UFES), Fernando Ferrari Avenue, Vitória, 29075-910, Brazil
² Mechanical Engineering Department, Federal University of Espírito Santo (UFES), Fernando Ferrari Avenue, Vitória, 29075-910, Brazil
³ I3N & Physics Department, University of Aveiro, Aveiro, 3810-193, Portugal
This paper presents the development of a bioinspired multifunctional flexible optical sensor (BioMFOS) as an ultrasensitive tool for force (intensity and location) and orientation sensing. The sensor structure is bioinspired in orb webs, which are multifunctional devices for prey capturing and vibration transmission. The multifunctional feature of the structure is achieved by using transparent resins that present both mechanical and optical properties for structural integrity and strain/deflection transmission as well as the optical signal transmission properties with core/cladding configuration of a waveguide.
In this case, photocurable and polydimethylsiloxane (PDMS) resins are used for the core and cladding, respectively. The optical transmission, tensile tests, and dynamic mechanical analysis are performed in the resins and show the possibility of light transmission at the visible wavelength range in conjunction with high flexibility and a dynamic range up to 150 Hz, suitable for wearable applications. The BioMFOS has small dimensions (around 2 cm) and lightweight (0.8 g), making it suitable for wearable application and clothing integration. Characterization tests are performed in the structure by means of applying forces at different locations of the structure.
The results show an ultra-high sensitivity and resolution, where forces in the μN range can be detected and the location of the applied force can also be detected with a sub-millimeter spatial resolution. Then, the BioMFOS is tested on the orientation detection in 3D plane, where a correlation coefficient higher than 0.9 is obtained when compared with a gold-standard inertial measurement unit (IMU). Furthermore, the device also shows its capabilities on the movement analysis and classification in two protocols: finger position detection (with the BioMFOS positioned on the top of the hand) and trunk orientation assessment (with the sensor integrated on the clothing).
In both cases, the sensor is able of classifying the movement, especially when analyzed in conjunction with preprocessing and clustering techniques. As another wearable application, the respiratory rate is successfully estimated with the BioMFOS integrated into the clothing. Thus, the proposed multifunctional device opens new avenues for novel bioinspired photonic devices and can be used in many applications of biomedical, biomechanics, and micro/nanotechnology.
