Optical devices go beyond imaging applications

Article By : John Dunn

Presenting pictures of beautiful scenery is big deal stuff, but there are non-imaging optics applications too.

Not every optical device is involved with the art of presenting images. Showing pictures of beautiful scenery or presenting pictures of advertised products is big deal stuff, but there are non-imaging optics applications too.

Consider for example this ceiling light fixture I once photographed at a conference room/dining hall:

[EDNA lighting 01]
__Figure 1:__ *Ceiling light fixture*

This thing is actually quite complex. The light sources and the contoured glass cylinders have been set up for what amounts to quite a striking visual effect. Is it art? I don't know, but somebody made it and got paid good money for doing so.

Now consider something called the Fresnel lens. There is a very nice description of those things on Wikipedia. Originally developed for use in lighthouses, their purpose is to take in all of the light that impinges on the lens on one side from some light source and send it all in the same direction with less weight than would be required using any other alternative methods of achieving light directivity.

[EDNA lighting 02]
__Figure 2:__ *Fresnel lens*

There are no pictures involved, no images of a well turned ankle or of a tempting cold beverage. The goal is just to provide a visible light that can stay visible to passing ships at the greatest possible distance.

Another use for the Fresnel lens is in stage lighting. A type of spotlight called a Klieg light is often made with a Fresnel lens and a curved reflector to make a highly directional light source that will let a delighted audience clearly see their favourite performer(s).

Oh look! There's that well-turned ankle.

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