The Fraunhofer Institute for Photonic Microsystems IPMS is a leading research and development center for micro-electromechanical systems (MEMS). Recent developments focus on exploiting the existing technological base to develop ultrasound components. The Fraunhofer IPMS approach here uses a special MEMS technology that is highly reproducible and reliable in manufacturing. Besides the technologically intrinsic capability of producing millions of identical units, it can also be used for integrating driver and evaluation electronics in one chip together with the ultrasound transducer, making for complex and reliable systems that can be manufactured in large quantities at lower cost. The components are manufactured to be RoHS-compliant in accordance with the European Parliament and Council Directive, and thus without the use of hazardous or toxic materials. They meet the requirements for Registration, Evaluation, Authorization and Restriction of Chemicals (REACH).

Functionality of the CMUTs

The capacitors manufactured on silicon wafers use one of the electrodes as a spring and can therefore oscillate dynamically. The Fraunhofer IPMS technology allows the structures to be stimulated within a broad frequency range to generate ultrasound signals. These CMUTs (capacitive micromachined ultrasound transducers) can both generate and receive ultrasound signals.

Detecting middle-ear infections reliably

Fraunhofer IPMS cooperates with OtoNexus Medical Technologies in the field of ultrasound transducers. OtoNexus develops innovative medical devices for the fast and accurate provision of quantitative information to assist physicians in diagnosing middle ear infection (otitis media). By implementing a unique type of CMUTs, this new kind of probe can be used to examine the human auditory canal to analyze the area behind the eardrum within seconds. With that capability it can be determined whether the middle ear contains air or fluid and a differential diagnosis can be made between various disease conditions. This valuable information helps clinicians decide if a course of antibiotics is needed.