Flat lens - is this the breakthrough it seems to be?

Started Aug 12, 2013 | Discussions thread
photoreddi Veteran Member • Posts: 7,886
Re: ya can't trust those scientists

meanwhile wrote:

I asked one of the researchers about the comparison to Fresnel lenses and he disagreed, with explanations as to why. Waiting to hear back whether it's OK to post that reply here.

If you look at an illustration of a section of a fresnel lens you'll see that it basically doesn't change any properties of a lens, it just produces a much lighter lens by removing glass from the interior. I'd guess that the greater number of edges would increase the severity of edge effects, reducing image quality, but the lens would weigh a lot less if the lenses being replaced were large and thick.

Fresnel lenses were originally designed for lighthouses to efficiently focus the lighthouse's beams, where image quality wasn't as concern.


Lighthouse fresnel lens at Point Arena Lighthouse Museum

A Fresnel lens (pronounced /freɪˈnɛl/ fray-NEL or /ˈfrɛznəl/ FREZ-nel) is a type of compact lens originally developed by French physicist Augustin-Jean Fresnel for lighthouses.[1]

The design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design. A Fresnel lens can be made much thinner than a comparable conventional lens, in some cases taking the form of a flat sheet. A Fresnel lens can capture more oblique light from a light source, thus allowing the light from a lighthouse equipped with one to be visible over greater distances.


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