09:15 〜 09:30
▲ [25a-E305-2] Measurement of Piezoelectric Charge Coefficient of Piezoelectric Materials by Laser Displacement Sensor
キーワード：piezoelectric materials, Laser Dispalcement Sensor, piezoelectric charge cofficient
Lead- free piezoelectric material are in focus to reduce the environmental damage and hazard2). In this research, piezoelectric properties of PZT disc and synthesized KNbO3 films on LiTaO3 were characterized by using Laser Displacement Sensor (LDS). LDS is the convenient way to detect noncontact vibration measurement of the material surface with high accuracy. LDS is used as a vibrometer to measure the dynamic displacement and the function generator give the input and output signals to produce the frequency response and input voltage. From this value, piezoelectric charge coefficients (d) of PZT and KNbO3 film were calculated.
Figure 1 shows the piezoelectric charge coefficient changes of PZT disc for three different frequencies, 2kHz (lower than resonant frequency), 2.2kHz (resonant frequency) and 2.4kHz (higher than resonant frequency) at excitation voltage from 0.5V to 5V with the step of 0.5V. At resonant frequency, d value was 0.43μm /V at 3.5V which is larger than that of other two frequencies. The piezoelectric coefficient values of PZT were comparable with the reference value1). Based on results of PZT, piezoelectric charge coefficient of KNbO3 films were measured for 359.2kHz (experimental resonant frequency, fr(exp)), and 706.6kHz (simulation resonant frequency, fr(sim)). Figure 2 shows the results for two resonant frequencies at 0.5V to 5V with the step of 0.5V. KNbO3 results also show the same trend as PZT. At fr(exp), d value was 0.62μm /V at 3.5V which is larger than that of simulation resonant frequencies. Experimental results show, the digital measurement system based on LDS can measure the piezoelectric charge coefficient of PZT disc and KNbO3 film.
Figure 1 shows the piezoelectric charge coefficient changes of PZT disc for three different frequencies, 2kHz (lower than resonant frequency), 2.2kHz (resonant frequency) and 2.4kHz (higher than resonant frequency) at excitation voltage from 0.5V to 5V with the step of 0.5V. At resonant frequency, d value was 0.43μm /V at 3.5V which is larger than that of other two frequencies. The piezoelectric coefficient values of PZT were comparable with the reference value1). Based on results of PZT, piezoelectric charge coefficient of KNbO3 films were measured for 359.2kHz (experimental resonant frequency, fr(exp)), and 706.6kHz (simulation resonant frequency, fr(sim)). Figure 2 shows the results for two resonant frequencies at 0.5V to 5V with the step of 0.5V. KNbO3 results also show the same trend as PZT. At fr(exp), d value was 0.62μm /V at 3.5V which is larger than that of simulation resonant frequencies. Experimental results show, the digital measurement system based on LDS can measure the piezoelectric charge coefficient of PZT disc and KNbO3 film.