红外热成像法测量薄膜热物理参数

A method for measuring the in-plane thermal conductivity of self-suspended films using steady-state infrared thermal imaging has been studied. Starting from the one-dimensional heat conduction equation, a theoretical model of the temperature distribution on the film surface in the steady state has been established. Using the steady-state theoretical model, the in-plane thermal conductivity, emissivity and heat flux can be obtained simultaneously only by measuring the temperature and thickness at the edge of the film, without the need to measure the absorptivity of the film for visible light. Simulations show that when the temperature rise of the film does not exceed 5K, it can be ensured that the error between the fitted in-plane thermal conductivity and the theoretical value is less than 3%, and the minimum size of the film sample in the x-direction is 6 mm. Experimental measurements were carried out on a self-suspended polyimide film with a thickness of 900 nm, and the fitted in-plane thermal conductivity was 2.04 W/mK, the infrared emissivity was 0.92, and the heat flux at x = 0 was 1.77×10⁻⁴ W/m². The experimental results are consistent with the measured values in the literature, proving that the method can be used to measure the in-plane thermal conductivity of self-suspended films.

研究了一种利用稳态红外热成像法实现自悬浮薄膜面内热导率测量的方法。从一维热传导方程出发,建立了稳态时薄膜表面温度分布的理论模型,利用稳态理论模型,只需测量薄膜边缘温度及厚度,便可同时得到面内热导率、发射率及热流,无需测量薄膜对可见光的吸收率。仿真表明,当薄膜的温升不超过5K时,可以保证拟合得到的面内热导率与理论值的误差低于3%,薄膜样品x方向的最小尺寸为6mm。对厚度为900nm的自悬浮聚酰亚胺薄膜进行实验测量,拟合得到的面内热导率为2.04W/mK、红外发射率为0.92、x=0处的热流为1.77×10~4W/m~2。实验结果与查阅文献的测量值一致,证明方法可以用来测量自悬浮薄膜的面内热导率。