| The micro heater is a vital part of the sensor,providing a suitable working temperature for the sensing element,protecting the sensing circuit and improving the sensing sensitivity.With the development of flexible electronic devices,various sensing elements are widely used in flexible electronic devices in order to monitor the living environment and human health.At the same time,in order to meet the needs of flexible wear,higher requirements are put forward on the mechanical and electrical properties of the heating circuit of the micro heater.This paper proposes a graphene-based micro heater based on picosecond laser technology,and changes the type and structure of the heating circuit according to the actual heating requirements,and conducts simulation and experimental comparison research.The main research contents of this paper are as follows.(1)This paper proposed a graphene thin film micro heater based on picosecond laser technology according to actual needs.By changing the type and structure of the heating circuit,three types of heating electrodes with different circuit shapes in series and parallel circuit structures are designed.(2)The finite element software is used to simulate the series and parallel circuit structure of the micro heater,then thermal performance and current density of the circuits are compared and analyzed.The research results show that under the same voltage condition,the steady state temperature of the series circuit structure of the micro heater is lower,and the steady state temperature is greatly affected by the circuit shape.Because the resistance of the series circuit structure is significantly greater than that of the parallel circuit structure.As a result,the current through it is smaller,and the Joule heat generated is also smaller.(3)Through experimental tests,the best spin coating parameters were selected,then the graphene film with uniform thickness was produced.This research adjusts the various process parameters of the picosecond laser,compares and summarizes the picosecond laser energy density,scanning speed and scanning times that are most suitable for the production of the heating circuit.Observing the surface characteristics of the fabricated heating circuit,the result shows that the picosecond laser technology has high processing accuracy.The fabricated heating circuit has excellent performance,and the selected laser process parameters meet the design requirements.(4)Perform temperature test on micro heaters with parallel circuit structure,observe the steady-state temperature and heating trend of micro heaters of different circuit types.The research found that the shape of the internal heating circuit of the parallel circuit structure micro heater has little effect on the steady-state temperature,and the heating trends of the micro heaters of various circuit shapes are similar.The main reason is that the heat of the micro heater with parallel circuit structure is mainly concentrated on the boundary circuit.The ultra-high thermal conductivity of graphene can quickly conduct heat to various positions of the heating circuit,which leads to the heating trend of the micro heaters of various circuit types are similar.However,due to the difference in the shape of the internal circuit,the temperature distribution of different micro heaters is not uniform,and the steady-state temperature is different.The temperature distribution of the parallel circuit structure can be adjusted and optimized by changing the internal circuit shape of the micro heater.The graphene-based micro heater fabricated based on the picosecond laser process proposed in this paper can overcome the problem of poor mechanical performance of traditional heaters.The simulation analysis results of the micro heater model are consistent with the experimental results.The research results have certain guiding significance and reference value for the further research of micro heater for flexible sensing elements. |
