Capacitive sensor mats for pressure detection with high sensitivity
New flexible pressure sensor mats based on dielectric elastomers are described in this paper. They can be applied for the detection of compression loads on rigid as well as on compliant substrates. The measurements with the sensor mats exploit a capacitive principle, where the electric capacitance between integrated flexible electrodes is changed upon compression. The basic design of the sensor mats comprises two flexible profiles which include a thin elastomer film in a sandwich configuration. When the sensor mat is compressed, the profiles penetrate into each other and stretch the elastomer film, causing an increase of the capacitance between the electrode layers. The sensitivity and other characteristics of the sensor mats are determined by the shape of the profiles, the location of the electrode layers and properties of the elastomer materials used and can be tuned by these parameters. Some examples of such compression sensor mats are introduced and discussed. Intended applications are seat occupation surveillance, load detection of the human body or impact detection of machines and robots.