Fresnel lenses

Fresnel lenses are a type of compact, flat lens designed to focus or direct light efficiently. Instead of a traditional curved lens, they are made of a series of concentric rings, each acting like a small segment of a larger lens. This design reduces material and weight while maintaining a high level of focus. Originally developed for lighthouse beacons, Fresnel lenses are used in applications like overhead projectors, spotlights, and solar energy collectors. They allow for large, lightweight lenses that concentrate light or sunlight effectively, making them practical and versatile in various optical devices.