Planar polymer optical sensor networks for 2D strain measurement.

This project investigates the realization of large-area planar-optical sensor networks in thin polymer foils for distributed 2D strain or shape deformation measurement. Such sensor networks are a promising alternative to polymer-electronic or classical fiber-based sensor networks and offer advantages with regard to multiplexing, resource and cost efficiency and high-throughput production, e.g. by reel-to-reel. To achieve this goal, the sensor concepts for planar-optical polymer-based strain sensors demonstrated in previous work within sub-project C02 in the CRC/TRR 123 – PlanOS need to be extended to a fully integrated sensor network for measurement of strain and quantities derived from strain in 2D. This requires the integration of all relevant elements such as light sources, detectors, couplers and waveguides into a combined sensor structure equipped with high optical functionality. The ultimate goal is to demonstrate an almost full-polymer sensor network in thin foils which exploits purely optical principles for sensitive distributed sensing. Two new and fundamentally different scientific challenges need to be solved: (i) On one side, research on the sensor concepts is required with regard to achievable sensitivity, integration density, reproducibility, and compatibility of all processes involved (hot embossing, doctor blading, lamination, laser direct writing, and sputtering). A process chain needs to be realized which ensures that functional structures created are not compromised by subsequent steps. Also, the increasing complexity associated with the higher integration density as well as the implementation of calibration concepts are to be addressed and require the detection of additional quantities such as humidity and temperature. (ii) On the other side, the realization of planar-optical sensor networks represents a challenge for signal generation, analysis and recovery. As the precision of polymer-based elements is usually not as accurate as that of their glass-based counterparts the theoretical description and validation of all elements required for signal generation and transmission as well as design and implementation of full-scale networks need to be investigated. This requires a study of both functional sensor aspects and theoretical models for signal generation to identify the interdependence between the optical functionality and the network performance. The scientific challenges, i.e. the realization of integrated sensor networks using mostly polymer-based components, the robust data extraction from the network, the reproducibility and compatibility of all relevant production processes as well as the quantification and compensation of environmental influences will be addressed in close collaboration between the groups of B. Roth (realization of polymer-optical sensor networks) and J. Ostermann (network concepts and technologies as well as data extraction and recovery) exhibiting the complementary expertise required.