A phase differential heterodyne interferometer for simultaneous measurement of straightness error and displacement is proposed. In this interferometer, a modified mobile sensor composed of a Wollaston prism and a semi-reflective plane mirror is adopted to obtain the straightness error and displacement information simultaneously. A phase differential measurement is utilized to obtain phase differential signals for straightness error and displacement measurement, respectively, by using phase retarder and polarizing beam-splitter. Based on the relationship of $\pi$ phase difference between the nonlinear errors of phase differential signals, the periodic nonlinear error of measurement results can be compensated. Benefiting from this design, the proposed interferometer can not only obtain the straightness error and displacement simultaneously, but also reduce the nonlinearity of measurement and the influence of the measured object’s rotation. The optical configuration and measurement principle are described in detail. The influence of Wollaston prism’s roll error is also discussed. And three verification experiments are presented at last.

提出了一种用于同时测量直线度误差和位移的相位差外差干涉仪。该干涉仪采用由沃拉斯顿棱镜和半反射平面镜组成的改进型移动传感器，同时获取直线度误差和位移信息。通过使用相位延迟器和偏振分束器，利用相位差测量分别获得用于直线度误差和位移测量的相位差信号。基于的关系$\pi$相位微分信号非线性误差之间的相位差，可以补偿测量结果的周期性非线性误差。受益于这种设计，所提出的干涉仪不仅可以同时获得直线度误差和位移，而且减少了测量的非线性和被测物体旋转的影响。详细描述了光学配置和测量原理。还讨论了沃拉斯顿棱镜的滚动误差的影响。最后给出了三个验证实验。