How does a fresnel lens

When seen from a distance, these six beams produce six 1. Most observers are unaware that this repetitive second flash pattern is unique to the Ponce Inlet Lighthouse. Even fewer understand how a single watt light bulb located in the lantern room can produce the concentrated beams of light that pierce the darkness more than 18 miles out to sea. The light or "beacon" that is projected out from the top of the Ponce Inlet Lighthouse is produced by a Fresnel lens, a special kind of optic that has been used in lighthouses around the world since the early nineteenth-century.

They were invented by a French physicist named Augustin-Jean Fresnel in and completely revolutionized lighthouse technology. A Fresnel lens creates this bright beam of light using glass prisms set in metal frame.

These prisms change the direction that light is traveling in so all the light exits the lens in same direction. The prisms do this by refracting or bending light and reflecting it as well. Refraction is the scientific word that is used to describe how light is bent as it enters or exits a dense transparent material or medium like glass at angle other than 90 degrees. Reflection occurs when light bounces off the surface of smooth, shiny material like metal, glass, or water.

Reflection can occur on both the interior and exterior surface of transparent object. Each ring is slightly thinner than the next and focuses the light toward the center. Now take each ring, modify it so that it's flat on one side, and make it the same thickness as the others. To retain the rings' ability to focus the light toward the center, the angle of each ring's angled face will be different.

Now if you stack all the rings back together, you have a Fresnel lens. You can make the lens extremely large if you like. Fresnel studied light and optics in the 19th century. Click here to find out more. Sign up for our Newsletter! Mobile Newsletter banner close. Mobile Newsletter chat close. Mobile Newsletter chat dots. Mobile Newsletter chat avatar. Mobile Newsletter chat subscribe. Physical Science.