Natwerk Designs

How to design a fresnel lens and can any one gimme a practical design example?

The fresnel lens, to be designed is to use in automobile lighting applications and for PDA displays. I need some nice books/websites/references for the design process. An example for calculating the facet angle, valley and peak values, relief angles and values would be nice.

Public Comments

1. this site has places that you can purchace them
2. A Fresnel lens basically approximates the curvature of a spherical lens in small coaxial segments; the result being the same as if you cut a plano-convex or plano-concave lens into such segments and then cut off a hollow cylinder of material from each segment such that what remains is, roughly, the curved top, a newly-cut flat bottom, and one vertical side (i.e., a near-triangular cross section). Obviously some material needs to be left to hold all these segments together, so there will be a small fourth side, i.e. a constant added thickness. The 'curved' top may actually be flattened for easier manufacture. Some old lighthouses use concentric circular 3-sided prisms, a real approximation. I'd guess that segment size, valley and peak values depend on the material's mechanical properties more than optics.