Touch sensor for micromanipulation with pipette using lead-free (K,Na)(Nb,Ta)O3 piezoelectric ceramics

Abstract

In the field of applied microbiology, a touch sensor for micromanipulation with a pipette is needed. Therefore, we previously developed a touch sensor using Pb(Zr,Ti)O3 (PZT). The piezoelectric material is used for vibration of the pipette and for measurement of the change in mechanical impedance caused by the pipette tip contacting the object being measured. However, the lead included in PZT can cause environmental problems. Therefore, in the present work, we developed a touch sensor using lead-free (K,Na)(Nb,Ta)O3 (KNNT) ceramics, which are strong candidates for lead-free piezoelectric ceramics. In this study, characteristics of a touch sensor utilizing piezoelectric vibration were theoretically derived. The results show that the piezoelectric constant d31 is very important: the higher the mode of vibration, the smaller the tip amplitude; the lower the mode of vibration, the higher the sensitivity. Also, the higher the elasticity or viscosity of the object in contact with the sensor, the higher the sensitivity. These theoretical results qualitatively correspond to the experimental results. The piezoelectric constant d31 of KNNT ceramics was measured, and its value was found to be greater than or equal to 100pm∕V. KNNT ceramics were applied to the touch sensor and its utility was confirmed.

Depth-detection methods for microgripper based CNT manipulation in a scanning electron microscope

“…Although similar systems have been reported previously [2,15] the main advantage of this touchdown sensor is its ability to be adjusted to the tool and thus the application. Furthermore, a dynamic threshold algorithm adopts its sensitivity to the disturbances of the handling system.…”

Piezoelectric Vibration-Type Tactile Sensor Using Elasticity and Viscosity Change of Structure

“…When (2) and (8) are substituted in (4), constant is expressed as (10) where (11) When (2) and (10) are substituted in (3), the displacement is expressed, as shown in (12) at the bottom of the page, where (13) Next, the output voltage induced by the piezoelectric effect is derived. The output voltage is expressed as (14) where is the quantity of electric charge, is the electric capacitance, is the surface area, and is the electric displacement. The fundamental piezoelectric equation is expressed as [16], [17] …”

“…1, but also in various fixed conditions, such as both ends being supported or both ends being fixed in place, and the pressure resistance is adjusted by proper selection of the substrate. Since piezoelectric vibration-type sensors have a high sensitivity and high pressure resistance, they have been used for scanning force microscopy (SFM) [12] and as a touch sensor for micromanipulation [13], [14]. However, since such sensors easily become saturated with a large change in mechanical impedance, their measurement range is extremely narrow even though they have a high sensitivity for a small change in mechanical impedance.…”

Depth-Detection Methods for CNT Manipulation and Characterization in a Scanning Electron Microscope

“…Although similar systems have been reported previously [22,23], the main advantage of this touchdown sensor is its ability to be adjusted to the tool and thus the application. Furthermore, a dynamic threshold algorithm adopts its sensitivity to the disturbances of the handling system.…”