Investigation of Quartz Tuning Fork’s Dimensional Impact on its Dynamics and Resonance Frequency

Abstract

The quartz tuning fork (QTF) is an excellent mechanical resonator consisting of two prongs. It is widely used as a time keeping element in watches and telecommunication industry due to its high frequency stability. Tuning fork has wide spectrum of applications for example Atomic Force Microscopy (AFM), near-field scanning optical microscopy (NSOM) and sensors like density, gas, pressure and viscosity sensor, biological sensor and quartz-enhanced photoacoustic spectroscopy (QEPAS). For using QTF as a force sensor in atomic force microscopy, high quality (Q) factor, high force sensitivity and relatively low spring constant are desirable properties. The dimension of quartz tuning fork influences the eigenfrequencies, effective spring constant (keff) and sensitivity of the quartz tuning fork. We have investigated the dimensional and geometrical impact on eigenfrequencies, effective spring constant (keff) and sensitivity using analytical and simulation methods. The aim of study is to obtain an optimal design for the QTF having cantilever beam as the basic element with flexible base and enhanced sensitivity. The simulation and analytical results suggest that by reducing the coupling spring constant (kc) of tuning fork, the effective spring constant (keff) can be reduce while the sensitivity of tuning fork can be enhanced.