The Research Of Optical Dynamic Calibration Technology Of Temperature Sensor Which Is Based On CO₂ Laser And The Reflective Surface Of Off-axis Parabolic

The principle of traceable temperature sensor calibration is to use dynamic continuous laser to accurate temperature change on sensor surface, and it make thermometer and be calibrated to heat the sensor measured simultaneously. The principle of dynamic calibration now is widely used in Various disciplines, such as thermal technology equipment, power machinery, rocket engine, nuclear engineering etc. the aim of the research of dynamic calibration of transient surface temperature sensor is to use traceable, rapid temperature change to detecting the signal of various temperature sensor ,the characteristics of the time of dynamic response , And we will revise the results of measurement temperature, to make the results of its last data more closing to the real temperature signal curve, thus to achieve the purpose of reducing error of dynamic response.At present, in view of the dynamic calibration system the size of the laser spot can not adjustment: If laser spot of sensor probe is too small, the sensor produce heat very uneven. It will cause error, and the calibration results are not accurate; if the spot is too big to heat evenly, response time of system increases. And its calibration result is also not accurate. It cannot guarantee a sensor or microstructure heated evenly. At the same time, data length by an oscilloscope is too small and rate is too low, and so on. This paper puts forward the dynamic calibration system which is based on off-axis paraboloid. Its principle is to use flat mirror reflection laser to the surface of off-axis parabolic mirror, then this lens focused laser beam again. Compared with single lens, it eliminates the effect of thermal lens and spherical aberration, and it simplifies the original light path system, it also can get better quality spot. Oslo its more lenient for the spot shape of the focus being, its change the peak power to change the spot size by changing the size of the focal length .Its made more easy to adjust, And the ZEMAX software does simulation. In data acquisition systems, it use the data acquisition card with 4 channel, which Can simultaneously influence infrared detector and thermocouple temperature sensor, to make the collection rate higher and controlling more flexible. The new design of the dynamic calibration system which is based on off-axis paraboloid doing the test experiments for the time constant verified by experiment system design is feasible. According to the layout of the whole system, it designs the cabinet of shielded enclosure and the pedestal of off-axis parabolic reflective surface. It can also open the box at two sides. And it designs open mode with push-pull type on one side of the infrared detector. It makes the adjustment of detector position is more convenient.