Film Pressure Sensor Performance And Software Compensation

In this dissertation, the working principle of the thin film pressure sensor is studied, and the performance of the products is improved through the research and improvement of the chip technique. The integrated circuit and the compensation software are applied to compensate the pressure sensor error effectively, therefore the measurement of the product is made more accurate and the product is made more digital and intelligent.Through the adoption of the ion beam sputtering deposition technology various high performance thin films are successfully produced on elastic substrate. Through the application of Ta₂O₅/SiO₂ compound insulation film, the insulation resistance of 10000 MΩ is achieved at 250V.DC. The stability and temperature performance of the film resistance have improved effectively by a series of technique improvements, such as, choosing the high quality elastic substrate material and film resistance material, adopting the resistance film thickness ranging between 3000A and 5000A, heat-treating in N₂ atmosphere, sputtering SiO₂ film and spraying protection coating to protect the resistance film.Various performance compensation methods have been designed according to the characteristic of the thin film pressure sensor. The simplest and most efficient compensate method is to join up the resistance in series in the film resistance bridge. To compensate the zero offset with a small film resistor, which is prepared on the same chip, the compensation precision is over 0.5%, and the zero temperature drifting is nearly less than 0.01%FS/℃. The XTR106 signal processing circuit accepts low-level inputs from the thin film bridge pressure sensor and convert it to the industrial standard 4²0mA, two-wire current loop, the nonlinearity characteristic of the sensor is compensated to higher precision simultaneously.The MAX1452 signal processing circuit designed for the thin filmpressure sensor can compensate the sensor signal and simplify the manufacture process through the application of compensation software and the standard serial digital interface part. It also improves the anti-interference of the products and the precision of the measurement.Through the research of this subject, the insulating ability, stability performance and temperature performance of the sensor have been improved. The precision of the compensated sensor reaches level 0.1 with the temperature range of -40 °C to 250 °C, and the sensor can stably and reliably work at harsh environment.The research and development of the thin film pressure sensor is discussed in this paper, it's meaningful to the development of high performance pressure sensor in the military area of our national defence.