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Oil Lens
Oil held in tension in an enclosing force field, used as an optical component. (Read the full article)
| "If you check the old (1930s) 3 volume set, Amateur Telescope Making by Scientific American you will find that there were water lenses. In the majority of achromatic lenses there is a front lens that is double convex and a back lens that is plano-concave. The front lens has a lower optical density (index of refraction). In *general* as the optical density of a material is higher, the increase in the amount that it disperses color is proportionally greater than the increase in the index of refraction. So the plano-concave element is made of an optically denser glass which cancels half of the magnification and effectively all of the color dispersal. The front element is called "crown" glass and is a pure form of window glass. The back element is generically called "lead" glass because the first such glasses had lead dissolved in them, which handled the color dispersal but was dark and absorbed light. Better glasses are now used.
But there was a compromise. Water has a lower optical density than crown glass. Some telescopes were made, even as late asthe 19th century where the back element was crown glass and the front element was a thin curved surface like the crystak of a pocket watch. That was filled with water.
Another note: Newton experimented with a prism made of 2 flat pieces of glass set like a trough. He filled it with water and measured the index of refraction and the color dispersal. Then he filled it with water with a chemical salt in it to increase the optical density. He discovered that the increase in color dispersal was exactly in proportion to the increase in refraction. He then formally reported to the world that an color corrected lens was impossible. He had had the bad luck to pick a material that was an exception. Newton's standing was so high that it was 75 years before anyone retested the matter.
That's still not a force field adjusted lens, though.
" (dhm 11/5/2005 7:31:57 AM ) |
| "As a child [around 15 years ago] i remember seeing a picture in a local philippine newspaper. Scientists tried out water lenses as a solar power heat source. Water was shaped by placing it in plastic bags under tension. Efficiency and focus was terrible but they could build lots of these for a very small cost. The pic shows one bag the size of your hand burning a 2 by 4 wood support " (Vince 12/21/2005 4:07:31 AM ) |
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