测量表面倾角对差动共焦瞄准信号影响分析

Effect of Tilt Angle of Surface to be Measured on Differential Confocal Microscope Pointing Signal

普通共焦显微镜的轴向响应特性,因受到被测量表面的倾斜角影响引从而起轴向响应特性变化,而应用差动共焦光学系统对超精密加工的表面进行瞄准测量时,差动系统的瞄准信号也受到影响,并进而影响到测量系统对加工表面的测量精度及分辨特性。通过对差动共焦测量系统输出信号理论模型的分析得出被测量面的倾斜角变化不影响差动共焦输出信号零点位置;倾角在一定范围内变化时不影响瞄准测量分辨力的结论,并给出了实验分析结果。

The axial response of conventional confocal microscope is affected by the tilt angle of the surface to be measured. When the ultra-precisely machined surface is measured with pointing method based on the differential confocal microscope, the tilt angle of the surface to be measured influences the pointing signal, as well as the measuring accuracy and resolution of the treated surface. On the basis of the analysis of the theoretical model of the output signal of differential confocal microscope, it is concluded that the zero point is independent of the tilt angle of surface to be measured and the resolution of the pointing signal is not affected with the tilt angle in a certain range. The experimental results are also presented.