Projection Fresnel Lens Linear to Spot Conversion

About: You may recognize Dan and Denise Rojas from their appearances in various made for tv movies and national commercials. As the hosts of Green Power Science, they share Fresnel lens and alternative energy ideas...

In this video, we share a process we have been perfecting for several years now. Converting a "Linear" Fresnel lens into a "Spot" Fresnel lens. Rear projection TV screens all have a circular Fresnel pattern on one side. A Spot Fresnel lens has a glossy smooth finish on the second side of the lens while a Linear Fresnel lens has vertical grooves that are very small, almost too small to see with the naked eye on the second side. By filling these grooves in with either resin, gloss enamel paint or removing them with a buffing process, the Linear beam becomes a Spot. This results in a clearer lens allowing more sunlight to pass through to the target area and because the focal pattern is tighter, the maximum temperature is increased dramatically. Sanding and buffing is the best option because there is less chance of unrecoverable errors that can occur with the other processes.



  • Organization Contest

    Organization Contest
  • Paper Contest

    Paper Contest
  • Remix Contest

    Remix Contest

4 Discussions

jack davis

Question 10 months ago

What brand TVs have the best fresnel spot lenses even if I have to sand the straight grooves off the back side?


Question 11 months ago

Do you have any suggestions/techniques on how to apply either the resin or the paint so that it is the most effective?


3 years ago

Am I missing something kr is the instructable incomplete? It seems theres only the introductory page

1 reply