后焦距
hòu jiāo jù
- back focal length
后焦距
后焦距[hòu jiāo jù]
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测量接触镜近轴后顶焦距可行性分析
Analysis of feasibility for paraxial back vertex length of contact lens
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目的：探讨接触镜的球差特征以及后顶焦距测量的实质。
Objective : To analyze the aberration properties of contact lens and its central back vertex power measurement .
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结论：焦度仪的入瞳2h与人眼瞳孔相匹配时，测量的接触镜后顶焦度就是接触镜实际后顶焦距&带高0.87h光线的像方截距L0.87h′的倒数。
Conclusion : When the incident pupil 2h of focimeter is corresponding with human pupil , the measuring value of the back vertex power is the real back vertex power of contact lens the reciprocal of distance on the orientation of image L0.87h ′ of band height 0.87h light .