Production of PyzoFlex®-Sensors
Production on an industrial scale is carried using a low-cost screen printing process. The finalized, printed sensors are electrically activated with a hysteresis poling and are, thereafter, multi-functional.
The substrate of the printed sensors is a transparent plastic substrate made of PET, but other materials such as glass or coated paper can also be used. In a first step, horizontally mounted ground electrodes are printed. Subsequently, the entire substrate is coated with functional or activated material. In the last step, a layer is applied with vertically mounted covering electrodes. The ground and upper electrodes are superimposed directly over one another and form a plate capacitor. Charge displacements in the intermediate ferroelectric layer generate an electric voltage between the two electrodes.
The sensor layer made of ferroelectric copolymer P (VDF-TrFE) is nearly transparent. If a more transparent sensor film is needed, the upper electrode can also be printed with PEDOT: PSS, resulting in about 85% transparency. Optimization for the detection of changes in temperature or IR radiation in the sensor film can be achieved by printing the uppermost electrode layer with a more highly absorbent carbon ink. A great advantage of this manufacturing method is that the printing process has few expensive requirements (cleanroom environment, vacuum vapor deposition, high temperatures) and, thus, enables a low-cost industrial production.