4 ms·
Fresnel Lens and Parabolic Reflectors
- corey_moncure 5y agoWhat's a flattened version of the parabolic reflector look like?
- ladberg 5y agoI think you're basically describing a concentrated solar plant, for example that giant array of mirrors on the way to Vegas (Ivanpah).
- aaron_m04 5y agoAh yes, the one that cooks birds in flight.
- analog31 5y agoNot quite the same thing, but the large mirror arrays used in those giant solar power plants are analogous, though without the circular symmetry of a Fresnel lens. An issue is efficiency: Each groove shadows its neighbor. In fact there's no reason why a Fresnel lens can't be made from rectangular panels instead of circular grooves, except that the latter are easy to cut on a lathe.
- gerdesj 5y agoPlane
- gerdesj 5y agoPlain
- samatman 5y agoThe reflexive honeycomb used ubiquitously in automotive contexts is exactly that.
- adolph 5y agoThe behavior of light between materials is very interesting. In the below Fermilab video "Why does light bend when it enters glass?" several theories are explained which helped me understand the principals involved. https://www.youtube.com/watch?v=NLmpNM0sgYk https://www.youtube.com/watch?v=NLmpNM0sgYk Can anyone suggest a good explainer on light reflection at a similar level to the Fermilab ones?
- aaron_m04 5y agoSearch for "how does refraction work" in YouTube?
- jalino23 5y agothe world of lenses have fascinated me since I learned about it after having to research why VR is blurry outside the sweetspot.
- mdaniel 5y agoMy experience with fresnel lenses growing up was with the sheet magnifiers my grandmother would use to read; I could melt asphalt with them and it acted like my own laser beam. I always wanted to make one of these solar cooking apparatus stands but it was ... frowned upon ... by my parents: https://www.bealsscience.com/post/2016/10/04/solar-death-ray-cooking-with-a-fresnel-lens-from-a-projection-tv https://www.bealsscience.com/post/2016/10/04/solar-death-ray...
- leephillips 5y agoAll of the light ray diagrams in the article are incorrect.
- thunderbong 5y agoCan you please elaborate? I couldn't figure out what was incorrect in them
- smat 5y agoNot sure which aspect the earlier post meant but the rays are only refracting on the exit surface, when of course they also refract on the entry surface.
- leephillips 5y agoThat’s it.