Textile Multitouch Force-Sensor Array Based on Circular and Non-Circular Polymer Optical Fibers

Analysis of Fibre Cross-Coupling Mechanisms in Fibre-Optical Force Sensors

“…The detected signal increases proportionally to the applied force starting from a minimum load of 0.28 N up to about 2 N. The fact that the linear increase does not start from zero can be explained by friction within the 3D-printed force-application rod. The results are consistent with the findings in [ 24 ] where melt-spun fibres out of harder materials like polymethyl methacrylate (PMMA) were used. It is obvious that the sensitivity of the signal increases for smaller coupling angles .…”

“…In [ 23 ] for instance, the losses induced by macro bending in a POF arrays have been used as sensor signal. In [ 24 ], the authors proposed a similar concept of a fibre-based textile touchpad. But this sensor array offered spatially resolved two-dimensional force sensitivity with multi-touch capability.…”

“…Rothmaier et al presented a textile integration of this pressure sensor [ 25 ], but none of the aforementioned methods were fully compatible with textile technology nor did they provide simultaneous sensing at different locations. The use of soft or elastomeric materials for POF sensing in general [ 26 , 27 , 28 ] and for this type of pressure sensing via POF [ 24 ] has shown promise and is therefore also addressed in the paper. Apart from these aspects, the authors investigated in [ 24 ] the coupling effect between the crossing fibres in more detail, studying the influence of different materials and mechanical properties of the fibre.…”

“…The use of soft or elastomeric materials for POF sensing in general [ 26 , 27 , 28 ] and for this type of pressure sensing via POF [ 24 ] has shown promise and is therefore also addressed in the paper. Apart from these aspects, the authors investigated in [ 24 ] the coupling effect between the crossing fibres in more detail, studying the influence of different materials and mechanical properties of the fibre. These proof-of-concept experiments showed the applicability of the effect, but did not investigate the cross-coupling mechanism much further.…”

An Overview on Methods for Producing Side-Emitting Polymer Optical Fibers

“…In so-called side-emitting POF (SE-POF), as a special form of POF, total internal reflection (TIR) is deliberately hindered and, thus, light leakage via the cladding of the fiber is induced [2]. This enables the use of POF for illumination purposes in which emitting light at the end of the fiber is not sufficient (e.g., in automotive or decorative lighting [3,4]) as well as innovative applications in the fields of medicine (e.g., antimicrobial applications for disinfection reasons and phototherapy [5][6][7][8]), security and military technology (e.g., protective waistcoats with localization of projectile entry or smart police uniforms [4,9]), fiber-optical sensing (e.g., fluid level sensors and MRI-compatible motion detection [10,11]) as well as for UV curing resins and adhesives [12,13]. As can be seen from the mentioned applications, SE-POF stand out from conventional lighting systems, such as LEDs or injection-molded light guides, due to various advantages: textile drapability and bendability, immunity to electromagnetic interferences, small required installation space due to low light guide thickness as well as the separation of light source and light emission [14,15].…”