Solid State Transducers

This paper reviews the development of solid state sensors and actuators during the last decade. Both solid state physical and chemical sensors suitable for use in the measurement and control of manufacturing processes will be discussed. The principle, the device structure and the performance of physical transducers for temperature, pressure, displacement, acceleration, flow, display, fluid injection and controlled fluid flow valves is summarized. Chemical sensors for humidity, combustive gases, ionic concentration in electrolytes and large molecule concentration are also outlined for their potential applications in automated manufacturing.The technology of micromachining, one of the bases for solid state transducers, is discussed with examples given to illustrate its capabilities and remaining problems.The possibility of integrating signal processing circuits on or near the transducer chip to fabricate “intelligent sensors” is presented along with the functions that can be incorporated on the transducers.Future trends in solid state transducer research and the possibility of beneficial collaboration between users and designers, as well as between material scientists, technologists, device designers and packaging engineers, is discussed.