Hi
I need some help designing a simple lens.
The lens will be injection molded in Acrylic, and will be used in toy. Picture below details Diameter and thickness. I need to know what the radii of of the lens faces should be to achieve a magnification of 2.5?
If anyone here with some optical knowledge could offer some help it would be much appreciated.
(ignore the radius of 316.51 it's just a wild guess)
I'm no expert, but I know the magnification is depedent on the desired focal length. The magnification will depend on how far away the source object and viewer are from the lens. For example, images displayed through a magnifying glass will have various magnfication depending on how close your eyes and the targeted object are from the lens. However, the targeted object will only be in focus (not fuzzy) within a specific range (depth of field). This isn't an answer to your question, but hopefully it will help you phrase your question such that it is answerable. Given the proper constraints (focal distance), it should posssible to derive the required radius for a given magnification using the thin lens formula. It is an approximation of actual lens behavior, but is usually sufficient for simple lenses.
I've always wanted to know how to do this myself. Thanks for asking.
Thanks to all those who offered constructive help, someone on the sci.optics group was especially helpful. They actually went to the trouble of doing a design in Zmax for me.
The radii of the surfaces in this instance are 392mm.Which compared closely to the result I had using the "Lens Makers Formula"
To quote the Zmax guy, "The attached analysis shows the imagery is pretty poor over the visual spectral range. For just the green mercury e-line (0.546074), it's diffraction limited."
However despite the "pretty poor" comment, it will be more than good enough in this situation.
John Layne
"John Layne"
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