Preparation And Test Of Fast Response Thin Film Temperature Sensor

Temperature sensors have been widely used in industry,aviation,medical and other fields as the crucial part of temperature measuring instrument.In recent years,with the arising of wearable devices such as smart bracelets and smart watches,the demand about monitoring human body and environment temperatures is increasing.To meet this requirement,the temperature sensor needs to be characterized by high response speed,high accuracy and compatibility with wearable devices.Based on the characteristic,the research on flexible wearable film temperature sensor is increasing.However,most of the research results show that the flexible temperature sensor's performance about precision,response time,repeatability,bending problem needs further exploration and optimization.With the development of material science and processing technology,many sensors can be produced by MEMS technology with a smaller size.This makes it possible to miniaturize conventional temperature sensors by existing processing techniques.Based on the above background,we proposes a micro temperature sensor which can be used to measure the human body and the outdoor environment rapidly.Specifically,the main research contents of my works are as follows:(1)Three kinds of thin-platinum film temperature sensors with snake-like patterns,whose volume is less than 3.1×1.5×0.5 mm~3,were successfully prepared.The minimum width of the snake-like pattern is 20?m.The static characteristics of the platinum film temperature sensor were tested.The test results show that in the testing temperature range of-15~75?,the max error of the three temperature sensors of different sizes prepared in this paper is about 0.2?,the average error of the three temperature sensors of different sizes prepared in this paper is about 0.1?,and the resistance temperature coefficient is about 0.00235/?.Then,the reason about the low resistance temperature coefficient is analyzed by formula.After that,the sensor had experienced several lifting cycles in the testing system,the measured hysteresis error of the temperature sensor is about 0.4%-0.5%,and the repeatability of the sensor isn't good by comparing the fitting straight between the sensor before testing and the sensor after testing.Finally,the temperature sensor of platinum film prepared was annealed at 700?for 1 hour in an air environment.SEM-EDS analysis of the platinum film section showed that high temperature intensified the diffusion of titanium to platinum film,which eventually led to the decrease of the temperature sensitive performance of the platinum temperature sensor.(2)The response time testing scheme for the platinum film temperature sensor prepared is proposed according to the specification of the dynamic response of the temperature sensor.At the same time,COMSOL software was used to simulate and estimate the response time of the prepared platinum film temperature sensor.The results showed that the response time calculated by COMSOL was less than 100 ms.Then we built the temperature sensor response time testing platform.After the construction,this paper analyzes and optimizes the test platform from three aspects:testing medium,influence of medium thermal field,and sensor transfer speed.Finally,the optimized time constant of the prepared platinum film temperature sensor was tested,and the experimental results showed that the minimum time constant of the prepared platinum film temperature sensor was about 230 ms.