Research And Experiment Of The Depth Sensor

In this paper, the depth sensor is designed to measure the navigation depth in thewater of an underwater weapon according to the characteristics of the workingenvironment of it. The working principle and process design of the sensor are described,and the performance of sensor is verified in accordance with the People’s Republic ofChina national military standard GJB4409-2002’ General specification for Piezoresistivepressure sensor’.The depth sensor can be aslo called the composite pressure sensors, composed of themechanical switch and pressure sensor. The integrated design is adopted, and it make thesensor possible to real-time monitoring system status. The power supply system of theweapon does not work by water-entry, and the sensor feels the depth by mechanicalswitch. When the weapon dives underwater30meters, the mechanical switch is operated,the power is turned on, a variety of test instruments and implementing agencies areworking. The pressure is converted into a voltage signal through pressure-sensitivecomponents which is the core component of pressure sensor, and then this signal isconverted into a standard signal by conditioning circuit.The piezoresistive effect of silicon is described in detail, and the silicon cupstructure, the substrate material of sensor sensitive chip are determined reasonably. Thestructure size, resistance, doping type, doping concentration of strain resistance are aslodetermined to improve stability of the sensor. Micro-mechanical processing technic of theflexible diaphragm, encapsulation technology of the sensor chip and the stressdistribution of monocrystalline silicon elastic diaphragm are researched during the sensorchip production process. The key technology of sensitive diaphragm corrosion and chipbonding are aslo solved.The3D modeling software is used for three-dimensional modeling of the sensor toensure the structural design reasonably, and to make full use of interior space duringoverall structural design of the sensor.The reasons of thermal drift and thermal sensitivity shift are introduced in sensorsignal processing. The method of temperature compensation is elaborated and designscheme of conditioning circuit and electromagnetic compatibility is given in detailed.Size parameters and material of the corrugated diaphragm welded bellowsmechanical switch welded bellows design process, design analysis, through thediaphragm process, to ensure that a mechanical pressure switch anti-overload stableperformance, and ultimately to accurately switch signal measurement.Finally, through the reliability design, derating design and experimentalverification, the depth sensor is validated the characteristics of stable performance, longlife, high accuracy and high overload.