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This article reports on the design of a capacitive pressure sensor fabricated in non-silicon materials. The sensor consists of a thin membrane placed parallel to a rigid reference plane. The membrane and the reference plane act as two electrodes of a capacitor. Deflection of the membrane due to pressure differences results in changes in capacity. These capacity changes are processed to calculate the pressure on the membrane. Several thermo-mechanical performance aspects of the sensor were addressed during the design stage. Promising variants of the sensor were built and subjected to mechanical tests. In addition, numerical techniques were utilized to assess the performance of certain variants before building and testing physical prototypes. The application of this combination of physical experiments and numerical simulations is demonstrated for the selection of a suitable membrane material and membrane dimensions (diameter and thickness), the specification of the substrate thickness in case the sensor is mounted on the backside of an electronics housing, and the selection of a suitable solder interconnect material and interconnect dimensions. A critical aspect in the latter case was the creep behaviour of the solder material, which had to be minimized in order to obtain an acceptable long-term accuracy of the sensor. A sensor membrane and an interconnect design were finally specified on the basis of the outcome of the design studies. It proved to meet the functional demands imposed by the targeted application on a laboratory scale. It will be subjected to reliability and lifetime assessment tests in a next phase.

The introduction in the market of ubiquitous sensing applications relies heavily on the availability of affordable sensors. Key in the cost of a sensor is its modus of manufacture. In this paper a sensing scheme is presented, in which the signal transduction is based on an induced change in the optical path between an organic light emitting diode (OLED) and an organic photovoltaic (OPV) array. Using this platform, several aspects of cost efficient manufacturing technology are investigated. These aspects include the intrinsic printability of the active (OLED, responsive coating and OPV) components, which allows control of the local sensor functionality and sensitivity. It offers a large amount of freedom in sensor layout, while using relatively few process steps. Also investigated is the ability to realize the active devices on foil, which enables high throughput processing (e.g. in a reel-to-reel scheme). Moreover, the presented generic sensing scheme is of a modular design. It allows easy switching of the sensor functionality mostly by simply changing the transduction module. Since this does not affect the production parameters of the other components, these may be standardized, thus invoking favorable economies of scale.

Monitoring of personal wellbeing and optimizing human performance are areas where sensors have only begun to be used. One of the reasons for this is the specific demands that these application areas put on the underlying technology and system properties. In many cases these sensors will be integrated in clothing, be worn on the skin, or may even be placed inside the body. This implies that flexibility and wearability of the systems is essential for their success. Devices based on polymer semiconductors allow for these demands since they can be fabricated with thin film technology. The use of thin film device technology allows for the fabrication of very thin sensors (e.g. integrated in food product packaging), flexible or bendable sensors in wearables, large area/distributed sensors, and intrinsically low-cost applications in disposable products. With thin film device technology a high level of integration can be achieved with parts that analyze signals, process and store data, and interact over a network. Integration of all these functions will inherently lead to better cost/performance ratios, especially if printing and other standard polymer technology such as high precision moulding is applied for the fabrication. In this paper we present an optical transmission sensor array based on polymer semiconductor devices made by thin film technology. The organic devices, light emitting diodes, photodiodes and selective medium chip, are integrated with classic electronic components. Together they form a versatile sensor platform that allows for the quantitative measurement of 100 channels and communicates wireless with a computer. The emphasis is given to the sensor principle, the design, fabrication technology and integration of the thin film devices.

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