为提高长程轮廓仪(LTP)面型检测的精度,提出一种使用波面型等光程多光束分束器的LTP。该分束结构可将入射光束分成若干束等光强等光程的相干光。在理论上分析计算了傅里叶变换(FT)透镜焦平面上干涉条纹的位置和强度分布,探究了零级干涉主极大条纹宽度、振幅和±1级干涉主极大条纹振幅与多光束分束器各结构参数之间的关系。通过选取合适的参数设计了基于多光束干涉原理的新型分束器,并与传统分束器进行了仿真实验比较,设计了测量系统中的准直镜和FT透镜,在Zemax软件中建立了完整的光学系统模型,并对该模型进行了实验验证。结果表明多光束干涉长程轮廓仪可以实现对被测表面斜率的测量,其在探测面上的干涉条纹宽度比传统双光束干涉窄,光强也更加集中,可以提高LTP的测量精度。 In order to improve the accuracy of long-range profilometer (LTP) face detection, an LTP using a wave-type isopacho-beam splitter is proposed. The beam splitting structure can split the incident beam into several beams and other light paths such as optical coherence light. In theory, the position and intensity distribution of interference fringes on the focal plane of Fourier transform (FT) lens are analyzed and calculated. The effects of zero-order interference fringes width, amplitude and amplitude of ± 1 interferometer main pole large fringes and multibeam Relationship between the structural parameters of the beam splitter. A new type of beam splitter based on the principle of multi-beam interference was designed by selecting the appropriate parameters. Compared with the traditional beamsplitter, simulation experiments were carried out to design the collimator lens and FT lens in the measurement system, and a complete The optical system model was validated experimentally. The results show that the multi-beam interferometer long-range profiler can measure the slope of the measured surface. The interference fringes on the detection surface have a narrower width of interference fringes than the traditional two-beam interference and the light intensity is more concentrated, which can improve the measurement accuracy of LTP.