Research On Polymer Wire Modified Quartz Tuning Fork Temperature Sensor

Those quartz tuning fork(QTF) sensors had been implemented as mass sensitive sensors or force sensors, which sensitivity polymer thin films were coated on the surface of QTF arm or polymer wire modified QTF, resonator based on the QTF is extremely sensitive to mass or stiffness change of the QTF. Those sensors have the advantages of compact structure, small volume, high resolution, good stability and so on.The QTF modified with a polymer wire as a temperature sensor, the role of the polymer wire is to provide a temperature sensitive element to the otherwise relatively thermal insensitive QTF. As the polymer is heated up, the stiffness of the polymer wire changes, resulting in a change in the effective spring constant of the QTF sensor, give rise to a change in resonance frequency of QTF. Not only keeping with inherent a high signal-to-noise ratio and a strong anti-interference ability, but also improving the sensitivity and response time of sensor. The sensor can be used in the field of precision temperature and also as an infrared detector.In this dissertation, a polymer modified QTF as a temperature sensor was improved. Not only the thermal sensitivity of the sensor was obviously higher than that of the traditional quartz tuning fork temperature sensor, but also shorten the response time. The researches about the theory, the design, the fabrication, and the detecting were performed. The main contributions of this work are listed as following:1. The research status of different kinds of quartz temperature sensors were firstly studied. And then the quartz resonant temperature sensors based on piezoelectric principles were reviewed in detail. Motivated by the above observation, the stratagem of the quartz tuning fork temperature sensors were taken out. The research objectives and contents of this work were developed respectively.2. The work principle of the sensor was researched, and structure of the sensor was also designed. Taking about the temperature frequency characteristic of the QTF was analyzed, the key factor to influence the performance of the sensor was analyzed and the new cut of quartz crystal was also designed. The high thermal sensitivity of polymer material was selected through the experiment method and the fabrication process was designed.3. Based on the elastic piezoelectric theory and the finite element method, the resonant mode and the harmonic response of QTF were analyzed by ANSYS software. The modified position of the polymer wire is analyzed, the higher sensitivity position to resonant frequency was got.4. The polymer wire modified QTF temperature sensor was prepared and the experimental setup of the sensor was designed. The resonant frequency change of device to temperature sensor were tested in operation from 0 to 80°C. Experiment result indicates that the high sensitivity of thermal can reach 8.2Hz/°C, the linearity of the sensor is 0.005%, the resolution of temperature can reach 0.003°C and the response time is lower 1.5s, repeatability is 0.006% when the fiducial probability is about 95%,and with good stability.5. To improve the accuracy of temperature measurement, a temperature sensor array with 17 elements was designed and the multi-sensor data fusion technology was applied. A sensor array signal processing circuit and a LabView program for data processing were developed.