Abstract: At present, silicon piezoresistive pressure/differential pressure sensor is widely used in servo system. But because the package structure of sensor internal pressure sensitive core is thin-film isolated, the tightness of silicone oil is the weakness of servo system with sensor for long-term pressure-bearing storage. According to the requirement of the servo system of pressure/differential pressure sensor, several piezoresistive pressure/differential pressure sensors without medium are developed, interior of sensor the silicone oil medium to transfer the pressure is avoid, and the reliability of sensor is ensured. Through research of sensor structure, and its performance test and contrast, a new choose for servo system with sensor is provided.

Key words: Without-medium, Silicon piezoresisitive, Pressure/Differential Pressure Sensor