薄膜测量的变间距不接触三电极技术

Space-Adjustable Non-Contact 3-Electrode Method for Thin Film Measurement

针对电气绝缘用薄膜材料相对电容率εr和介质损耗角正切tanδ的测量,IEC推荐了变间距不接触三电极方法。为了配合我国国家标准的制定及推广,自行研制了高精度的空气媒质变间距不接触三电极系统,其测量电极直径为38mm,保护间隙宽度为0.2mm,满足极薄(厚度小于30μm)的薄膜材料测量的特殊技术需求,可将εr的测量误差控制在5%以内,tanδ可测到10-5数量级。通过大量试验及理论分析,系统研究了影响测量准确度的关键因素,并将两种不接触电极方法进行了比较,以供相关技术人员作为实际应用时的借鉴和参考。

The space-adjustable non-contact 3-electrode method is recommended by IEC for εr and tanδmeasurement of insulating films. According to the national standard to be pushed, a high precision, air-medium, space-adjustable, non-contact, 3-electrode system is developed in the paper, and the measuring electrode is 38mm in diameter and the guard gap is 0.2mm in width. This electrode is specially designed for films thinner than 30μm, and it is proven that the measuring error of εr can be less than 5% and the order of tanδ reaches 10^-5. The key influencing factors are systematically researched in this paper through experiments and theoretical analyses. At the end, the two non-contact methods are compared for proper applicability.