Study Of Temperature Measurement Technique Based On Fluorescence Mechanism

With the continuous development of industrial production, we have higher demand to the temperature, so it is important to achieve accurate measurement of temperature. However, in some special circumstances, the thermometer can not measure the temperature accurately, even does not work. So people have been exploring new temperature measurement method. Fluorescence optical fiber temperature measurement technology is a new temperature sensing technology, compared to the traditional temperature sensor, fluorescence optical fiber temperature sensor has the features of corrosion resistance, high sensitivity, simple structure, electrical insulation and good, small size, light weight, high information content, fast response, low transmission loss and power consumption, etc. So the fiber sensor gets great attention of domestic and foreign scholars. In order to achieve real-time measurement of temperature in special circumstances, a set of fluorescence optical fiber temperature measurement system is researched and designed in this paper.The paper has studied the mechanism of fluorescence generated, analyzed the excitation and the inactivation process of the molecular, studied several common fluorescent material and analyzed the general characteristics of them, analyzed the relationship between fluorescence lifetime and temperature, listed several methods of temperature measurement using fluorescence and compared them, then selected fluorescence lifetime sensor, analyzed the non-exponential of the fluorescence and given some improvements.The mechanism of fluorescence lifetime detection using phase-locked principle is analyzed. The mathematic model of the phase-locked loop and the characteristic of noise are researched. The basic two-phase lock detection method is analyzed and the phase-locked loop of the system was designed.Based on the transmission characteristics of optical fiber, compared the characteristics of the different excitation light source, the stable and efficient excitation light source was selected. The paper has described the working principle of the photoelectric detector and analyzed its basic characteristics, structured the overall structure of the fluorescence optical fiber temperature measurement system, including the design of light source and its drive circuit, fluorescent fiber optic probe, optical detector and preamplifier circuit, filter circuit, PLL and MCU system.Two common methods of data processing are analyzed, Through comprehensive comparison, the method of the wavelet transform was selected. Finally, the experiment is taken and the experimental data is analyzed. The temperature measurement range and accuracy of the system are obtained.