Sensor applications of piezo are widely used and the number of applications is still increasing. In most of the sensor application it is not the piezo design itself that needs to be optimized but more the mechanics around the piezo. The mechanics forms a dominant factor in the performance and needs to make sure the maximum amount of charge is generated. The charge itself is equivalent with the introduced force to the piezo (i.e. deformation of the piezo). When forces (i.e. charges) are extremely small the electronic amplifier needs special attention.
Some examples are ;
- Crack detection / Non-destructive testing; By introducing a sound wave in for example a silicon wafer, the sensor response between an uncracked and cracked wafer is not identical. The difference determines the amount and size of cracks present. This approach is both known as crack detection as well as non-destructive testings.
- Deformation measurement; When applying a piezo sensor to a structure deformation of the structure also deforms the piezo sensor. The amount of generated charge is equivalent with the deformation. For some applications only detection of the signal is sufficient (for example in an airbag) for other applications strain levels of several picostrains (i.e. pm/m) can be precisely measured.