- published: 15 Aug 2011
- views: 333302
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.
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.
The idea of creating a thinner, lighter lens by making it with separate sections mounted in a frame is often attributed to Georges-Louis Leclerc, Comte de Buffon. The marquis de Condorcet (1743–1794) proposed grinding such a lens from a single thin piece of glass. French physicist and engineer Augustin-Jean Fresnel is most often given credit for the development of the multi-part lens for use in lighthouses. According to Smithsonian magazine, the first Fresnel lens was used in 1823 in the Cordouan lighthouse at the mouth of the Gironde estuary; its light could be seen from more than 20 miles (32 km) out. Scottish physicist Sir David Brewster is credited with convincing the United Kingdom to adopt these lenses in their lighthouses.
A quick demonstration of the difference between a Spot Lens and a Linear Lens, both of which are used in big screen TVs. The punchline being spot lenses can do everything that a linear lens can, and much more. Much higher temperatures achieved with a spot lens. The spot lens in this vid was taken out of the tv in this video https://www.youtube.com/watch?v=r87SZ3FmXIw at 1:15 into the vid. I can't remember the make and model, but you can at least see the type of console tv that it came out of.
Melting a brass padlock into a gooey puddle of metal using a gigantic Fresnel lens acquired from a rear projection television. More info at http://www.brotherswhitney.com .
Solar fresnel Lens.The solar tracker keeps our lens power on target for 8 hours a day enabling Fresnel build temperatures exceeding http://greenpowerscience.com 2100˚ Celsius, a new personal record. Just wait till big Daddy gets the same mount:-) The Fresnel lens history is here: http://www.youtube.com/watch?v=A_AFnW1bZL8
GreenPowerScience.com Linear projection TV Fresnel lenses are actually Spot Fresnel lenses with Linear grooves on the Non-Fresnel side of the lens. Sanding and buffing away these lines can increase the clarity of a Linear lens and make it a SPOT FRESNEL LENS. https://www.facebook.com/GREENPOWERSCIENCEGPS https://twitter.com/GREENPWRSCIENCE
From cooking your mind, to cooking your food, TVs get it done. This video shows where to acquire your free Fresnel lens. Then I'll take you step by step on how I build the frame and stand. The quality of these lenses will vary from one TV to the next, from high quality clear spot lenses, to thin, floppy, milky ones that aren't even worth framing in. The older, wooden console TVs have great spot lenses. The two TVs that were used in this video had decent linear lenses, but not the best. Seems like the older the TV the better the lens.
Melt a stack of pennies, burst a glass bottle, damage various food items, and incinerate wood using the power of the Sun! This 4 foot magnifying lens will melt concrete, and nearly anything else that gets in its way. Some quick links to a few of the materials I used: [✓] Small Fresnel Lens: http://amzn.to/2cEa9Sy [✓] Apple beer: http://amzn.to/2cVKC3C [✓] Bottle Top Stoppers: http://amzn.to/2cEcJrS Subscribe for new videos posted Randomly! https://goo.gl/618xWm Join my email list! http://bit.ly/TKOREmailList For other project videos, check out http://www.thekingofrandom.com Social Media Links: Google+: http://bit.ly/plusgrant Facebook: http://bit.ly/FBTheKingOfRandom Instagram: https://goo.gl/C0Q1YU Twitter: http://bit.ly/tweetgrant Pinterest: http://bit.ly/pingrant Tumblr: http://...
Solar Fresnel Lens used for steam engine power and steam production. Two differnt Steam engine models. http://www.greenpowerscience.com/
This is a very useful survival tool. If you going to the desert island, bring this item.
How to make a solar collector and concentrator from the fresnel lens that is found on many old rear projection televisions. I made this project from a sony KP-43HT20. This lens can ignite wood instantly and easily melt aluminum.