MadSci Network: Engineering |
Hmm, where to start?! Most optical instruments, such as telescopes, which use lenses can be redesigned to use mirrors instead to collect and focus light. This was first done by Newton - reflecting telescopes having some advantages such as no chromatic aberration and ease of construction; but some disadvantages such as having to arrange a more complicated light path so that the observer does to block the light! Simple ways of magnifying without "traditional" lenses would include use of a drop of water, or other liquid - quite effective on a small scale! Another kind of non-traditional lens is the "fresnel lens" which consists of concentric rings, a bit like a lens from which the solid middle has been removed, and the whole thing squashed flat. Probably my description isn't very illuminating - but fortunately you can see examples of such flat lenses in many over-head projectors and eg. devices to help see the rear of your car while reversing! The quality isn't very good, but they are large, cheap and convenient. I hope that gives you some food for thought!
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