Fabrication of micro tactile sensor for the measurement of micro-scale local elasticity

Abstract

Abstract In the recent past, atomic force microscopy (AFM) has been successfully applied to local elasticity measurement especially in biological fields. However, inevitable use of a cantilever results in difficulties in measurements and in sample preparation. Furthermore, the high cost of AFM systems prevents their widespread industrial and clinical use. In this paper, characteristics of local elasticity are evaluated by a new type of micro tactile sensor (MTS) developed with inexpensive and simple technology. MTS technology is based on simple ultrasonic contact sensing, and its high sensitivity is appropriate for micro-scale measurement. The sensor consists of a piezoelectric transducer and a needle-shaped 10-μm transduction point made with a glass needle. High stability and resolution are accomplished by applying a novel phase shift method. Young’s modulus of objects can be derived by analyzing the change in resonance frequency of the system. Using silicone samples with different degrees of Young’s modulus, a calibration equation for the MTS was calculated. Results show that with this novel MTS technology, micro-scale local elasticity measurement can be made without using conventional cantilever probes.