本文从莫尔偏折技术的基本原理出发,结合镜片屈光度的概念,分别从泰伯效应与光栅遮光阴影原理相结合以及菲涅耳-基尔霍夫理论的角度推导了变形后的莫尔条纹倾角与被测镜片屈光度的关系。两种方法推算结果是一致的,即:镜片的屈光度与透过镜片后产生的莫尔条纹的倾角的正切成正比。对影响镜片屈光度测量误差的几个参量进行了讨论,理论分析表明,选用合适的光栅周期,设定合理的两光栅间夹角,莫尔偏折技术用于测量低屈光度及中高屈光度的镜片具有很高的测量精度。最后给出了测量单光镜片、非球面镜片和渐进多焦点镜片的莫尔条纹图,并进行了分析讨论。

Based on the principle of Moiré Deflection Technology (MDT) and the definition of lenses’ power,relationship between moiré fringes’ tilting angle and the tested lens’s power is deduced respectively according to the combination of Talbot effect and principle of grating shadow and Fresnel-Kirchhoff theory. The calculated results are uniform that is lenses’ power is in the direct ratio to the tangent of moiré fringes’ tilting angle. Some factors that will affect the measuring error of lenses’ power are discussed. Analysis of the results shows that measurement of lenses’ power using MDT has high precision and it is feasible for lenses with low or middle-high power if proper period of gratings and reasonable angle between the two gratings are adopted. In the end,images of moiré fringes gotten by a single lens,an aspheric lens and a progressive addition lens are provided and analyzed.