Abstract
Electret condenser sensor with PFA film lamination using silica-agglomerates electret (FilmECS) demonstrates an excellent flexibility and low acoustic impedance compared with piezoelectric sensors. The dual sensors were prepared by lamination of the two FilmECS elements for measurement of a contact pressure and a hardness of soft material. The peak voltage Vp of the transmitting and receiving waveform was related to the contact pressure when the dual sensor was placed on the several soft materials. Furthermore, as the dual sensor was placed on softer material, higher attenuation of the waveform was observed. Eventually, the hardness of the tested materials was related to the centroid frequency of the waveform fc which was calculated from the FFT spectrum from 0.1 to 100 kHz. These results indicate that the dual sensor using FilmECS elements could be used for measurement of the contact pressure and the hardness of soft materials.
