表面倾斜对共焦显微测量轴向响应的影响

Theoretical Analysis of Surface Slope Measurement with a Confocal Microscope

应用基尔零夫公式对反射式共焦光路进行分析 ,给出了被测表面的法线与共焦光路的光轴不重合时的共焦轴向特性的理论模型。理论分析表明共焦轴向响应的半极值宽与被测表面的倾角大小无关。通过数值计算进行了仿真分析 。

When the measured surface is sloping, the coaxial condition is no longer met. Here, the response of confocal system derived from Fresnel is not complete. The theoretical model of confocal microscopy axial property is first inferred from the Kirchoff diffraction formula when the normal of the measured surface is not parallel with the optical axis of a confocal system. The theoretic analyses show that the full width at half-maximums (FWHM) of different slopes are the same and the FWHM of confocal axial response is irrelevant to tilt angle. The model is simulated numerically, and the result accords with the experiments.