Air Coupled Probe Integrity Test Using Same Type Probe on Parabolic Mirror

Design of the air-coupled ultrasonic probes require precise impedance matching to ensure efficient energy transfer to the air. The matching layers are soft so can be easily damaged by handling. Excitation voltages are high and might cause the degradation of electrodes, delamination between the layers and it can cause significant degradation of performance of air probe. Therefore, an integrity inspection is desired during transducer manufacturing and exploitation. Spatial distribution of a transduction efficiency over the probe surface was proposed as a convenient tool for the probe integrity inspection. In this research, a parabolic mirror is used for passive focusing of acoustic wave on the surface of inspected probe. This approach allows to avoid expensive focused transducer and replace it by same type air coupled transducers as probe under test. Moreover, focusing using the parabolic mirror is frequency independent, therefore such approach allows to inspect a wide range of air coupled ultrasonic probes.