光干涉技术是润滑薄膜厚度测量最有效的方法之一。双色光干涉法在保证较大膜厚测量范围及高测量分辨力的同时，避免了繁琐的干涉级次人工计数。传统的双色光干涉测量依赖于严格的静态标定和观测者。本文提出使用双色光干涉强度调制技术对微纳米润滑薄膜进行测量。通过干涉图像中红、绿分量强度值的线性叠加得到调制信号，根据信号特性分析得到特征位置膜厚，进而由干涉强度得到任一点膜厚。为验证所提出测量方法的正确，对静态球-盘赫兹接触表面间隙进行了测量，与经典理论有很好的一致性。结果表明：选用合适的红绿双色光波长，测量量程可达2μm。%Optical interferometry is an effective way for lubricating film thickness measurement. The dichromatic interferometry can avoid artificial fringe order counting, while operates with a fair resolution and a large film thickness measurement range. However, the traditional dichromatic interferometry depends on strict calibration processes and the observer. In this paper, a dichromatic interference intensity modulation approach is proposed for microano lubricating film thickness measurement, whereby linear superposition of the intensities of the red and the green components is carried out and a modulated signal is obtained to infer the film thickness at its local maximum/minimum. Thereafter the film thickness of other points can be obtained by the interference intensity of the red or green light. To validate this approach, contact gap between a steel ball and a glass disc was measured, and the results were well correlated with the theoretical calculation. A measurement range of 2μm can be achieved by an optimum selection of the wavelengths of the red and green lights.
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