Continuously rising demands on pressure sensors with respect to the long-term resistance in aggressive media, the usage temperatures, and the robustness require particularly resistant sensor systems, if possible in conjunction with integrated sensor signal processing. It is simultaneously required that such systems be producible by cost-effective manufacturing and have reduced system complexity.
For easy mounting in an application, sufficient mechanical stability, and to protect the actual pressure sensor element against external influences and to prevent corrosion due to aggressive media, pressure sensor elements are typically installed in housings, which consist, for example, of plastics or of material composites of plastic, ceramic, glass, and/or metal. Solder contacts, plug contacts, and/or cable feeds are integrated in the housings for the electrical connection. Suitable seals of such systems are produced using welds, soldering, seals, potting materials, and/or adhesives.
The pressure-tight connection of a pressure sensor element to the part of the housing supplying pressure is predominantly performed according to the prior art via sealing rings or organic adhesives, for example, polyurethane resins, silicones, epoxy resins, or mixtures thereof.
Sensor systems having plastic or metal housings are only usable in aggressive media to a limited extent because of corrosion occurrences. In particular the organic adhesive bonds between the system components represent a weak point with respect to the long-term resistance. Plastic housings are additionally incompatible with alternative joining technologies, for example, welds and soldered connections. Therefore, most sensor systems in the prior art consist of material combinations, which in turn require additional connections and make the systems very complex.
USPTO Backgrounds
USPTO Backgrounds