Measurement of the thermophysical properties of self-suspended thin films based on steady-state thermography

To measure the in-plane thermal conductivity and the infrared emissivity of thin films, a steady-state IR micro-thermography with simplified measurement procedure and new data processing method is presented in this paper. Thermal images at different optical heat intensities were collected by an IR camera. By subtracting two measurement results, the background thermal radiation was eliminated. Infrared emissivity, heat flux density and in-plane thermal conductivity were obtained by data fitting. The most important advantages of the proposed method were that the background thermal radiation was eliminated and the complicated optical absorption measurement was replaced by heat power measurement. We have performed measurements on self-suspended polyimide films with different thicknesses. For 504 nm thick film, the thermal conductivity and infrared emissivity in 7 similar to 14 mu m were 0.18 Wm(-1)K(-1) and 0.07, respectively. The measurement uncertainty of the thermal conductivity and infrared emissivity were lower than 13% and 10%, respectively, which were much lower than the previous reported value (20%) from the steady-state method. Our measurement procedure was suitable for analyzing thin films with a wide range of thermal properties. (c) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

为了测量薄膜的面内热导率和红外发射率，本文提出了一种具有简化测量过程和新数据处理方法的稳态红外微热成像技术。通过红外相机采集不同光热强度下的热图像。通过减去两次测量结果，消除了背景热辐射。通过数据拟合得到红外发射率、热通量密度和面内热导率。所提方法的最重要优点是消除了背景热辐射，并且用热功率测量取代了复杂的光吸收测量。我们对不同厚度的自支撑聚酰亚胺薄膜进行了测量。对于504纳米厚的薄膜，在7 - 14微米范围内的热导率和红外发射率分别为0.18瓦每米开尔文和0.07。热导率和红外发射率的测量不确定度分别低于13%和10%，远低于先前稳态方法所报道的值（20%）。我们的测量过程适用于分析具有广泛热性能的薄膜。（根据美国光学学会开放获取出版协议条款，2020年美国光学学会版权所有）