摘要
具有浮雕表面结构的透镜称为菲涅耳波带透镜，它具有体积小、重量轻等特点．在环 带相位深度Ｐ为２π时，菲涅耳波带透镜的焦距与其半径和环带数有关，而与相位阶数Ｌ无关． 理论和模拟计算表明，当环带深度改变２π的整数倍时，菲涅耳波带透镜的焦点将发生离散的 变化．当环带相位深度改变非２π的整数倍时，菲涅耳波带透镜由于能量将发散而无焦点．据 此分析，通过改变透镜材料的折射率，可以制作变焦的菲涅耳波带透镜．
Lens of the structure with relievo surface is called Fresnel zone lens, which has the feature of small volume and light weight. When the depth of phase equals to 2π, the focus of Fresnel zone lens is related to both the radius and the number of loops, however is independent to its phase grades. It is demonstrated by theoretical analysis and computer calculation that the focus of Fresnel zone lens will change discretely as the depth of phase changes with integral times of 2π. Otherwise, Fresnel zone lens will haven't a focus because of energy diverging. It can be inferred that the focus-variable Fresnel zone lens can be made by changing the index of refraction of material.
出处
《上海理工大学学报》
EI
CAS
2000年第1期57-60,共4页
Journal of University of Shanghai For Science and Technology
基金
原机械部重点学科基金!97101192
