在数字全息显微技术中，为了提高测量精度，提出了一种利用长工作距离物镜的相移数字全息显微的测量装置和方法。该装置采用LED作为照明光源，可以有效地抑制相位噪声，提高了重建精度。通过在长工作距离物镜和样品之间加入分光棱镜的方法，构建了一种准物参共路的迈克尔逊干涉仪。该装置结构简单，调整方便，在部分相干光照明时，容易实现干涉。重建时，采用盲相移干涉技术，结合两步盲相移算法，重建出物体的表面相位分布。实验中，分别采用LED照明和He-Ne激光照明，测量了一个反射式USAF1951分辨率板的高度分布。结果表明，两者的测量结果相互吻合，但是LED照明时的噪声与激光照明时相比降低了70%。此外，为了进一步验证装置的有效性，使用该装置对刻于硅基底的微纳矩形台阶进行测量，测量结果与标称值具有良好的一致性，表明该装置在微结构的形貌测量方面有广阔的应用前景。

In order to improve the measurement accuracy, a kind of phase shifting digital holographic microscopy based on a long working distance microscopic objective is proposed. In the setup, an LED is adopted as the illumination light source, which can suppress coherent noise effectively and hence improve the measurement accuracy. A michelson quasi-common-path interferometer is constructed by adding a beam-splitter between the long working distance objective and the sample. The layout of the setup is simple and it can be easily adjusted, and thus the interference can be come into being conveniently especially when the sample is illuminated with a partial light source. The blind phase-shifting interferometry is adopted in the reconstruction procedure, and the two-step blind phase-shifting algorithm is used to reconstruct the phase map of the measured sample. In the experiments, the height maps of a reflective USAF 1951 resolution target are measured under LED illumination and He-Ne laser illumination, respectively. The measurement results show that both coincide with each other; the phase noise under LED illumination is, however, reduced by 70% when compared with that under laser illumination. In addition, in order to further verify the effectiveness of the device, the device is used to measure a micro-nano rectangular step engraved on the silicon substrate. The measurement results are in good agreement with the nominal values. This technique can be potentially used in the topographic measurement of micro-structures.