Kombinierte Dehnungs- und Näherungssensoren für multifunktionale Oberflächen

The connection of touch-based pressure or strain sensors and touch-less proximity sensors offers far-reaching possibilities for novel human-machine interfaces. With the combination of two different sensoric principles, the activation and triggering of functions for the operation of machines can be completely separated from each other, in order to avoid misuse. Such multifunctional surfaces have been realized with two different classes of smart materials. In a first approach, piezoelectric thin films with high sensitivity for strain have been combined with capacitive proximity sensors. The approach of the hand or of an object and the push onto a surface are detected separately and can therefore trigger different functions. In the second approach, dielectric elastomer sensors for the capacitive detection of pressure or stretch have been connected to proximity sensors. Since for both sensors, identical materials and capacitive measuring techniques are used, a high degree of integration is possible. In this contribution, the two approaches for a combination of touch-based and touch-less sensors are introduced. The problems which have to be solved and solutions for the technical realization of the sensor systems are discussed. The combined sensors offer big potentials for a multitude of applications in automotive and traffic technology, in industrial automatization as well as for consumer products