Optical Design using Fresnel Lenses ORAFOL（使用菲涅耳透镜ORAFOL光学设计）.pdf

Optical Design using Fresnel Lenses Basic principles and some practical examples ∗ † Arthur Davis and Frank K¨uhnlenz Reflexite Optical Solutions Business Abstract The fresnel lens can be used in a wide variety of applications. The basic principles of the fresnel lens are reviewed and some practical examples are described. There are definite advantages and tradeoffs that should be considered when deciding if a fresnel lens is the appropriate component to use in a design. Some basic optimization rules are presented which may facilitate a first order design or feasibility study. Keywords: fresnel lens, microstructured optics, plastic lens 1 Background A fresnel lens is an optical component which can be used as a cost-effective, lightweight alternative to conventional continuous surface optics. The principle of operation is straightforward enough: given that the refractive power of a lens is contained only at the optical interfaces (i.e. the lens surfaces), remove as much of the optical material as possible while still maintaining the surface curvature. Another way to consider it is that the continuous surface of the lens is “collapsed” onto a plane. An example of this concept is shown in Fig. 1. The practical aspect of compressing the lens surface power into a plano surface requires a finite prism pitch, a slope angle component (which acts to refract the rays in the prescribed manner) and a draft component (which for the normal refractive lens design is optically inactive but necessary to return the surface profile “back to the plane”). See Fig. 2 for a cross section schematic illustrating these components. The convention is to specify the slope angle with respect to the plane of the lens and the draft angle with respect to the normal. For example, a