Fresnel lens

American  

noun

1. Optics. a large lens with a surface of concentric grooves of prismatic profile, used in automobile headlights, searchlights, spotlights, etc.

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Fresnel lens British  

noun

1. a lens consisting of a number of smaller lenses arranged to give a flat surface of short focal length

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Fresnel lens Scientific  

/ frə-nĕl′ /

1. A thin optical lens consisting of concentric rings of segmental lenses and having a short focal length. Placing a light source at the focal point of the lens gives rise to a strong beam of nearly parallel rays. Fresnel lenses are used primarily in spotlights, lighthouses, and the headlights of motor vehicles.

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Etymology

Origin of Fresnel lens

First recorded in 1840–50; see origin at fresnel

Example Sentences

Before the 11 a.m. boat ride back to the mainland, Dre Elmore likes to show off the retired Fresnel lens and the array of still-working machinery in the fog signal building.

From Los Angeles Times • Jan. 11, 2024

Even non-lighthouse enthusiasts can appreciate the museum’s enormous 1888 Fresnel lens.

From Seattle Times • May 24, 2023

The next morning, I went to the visitor station, in the recently refurbished fog signal building, to see the lighthouse’s original, first-order — as the biggest versions are called — Fresnel lens on display.

From New York Times • Mar. 27, 2023

It’s the end of the 19th century where a Fresnel lens is commonplace in the top of a lighthouse beacon and you can have a bellowing foghorn.

From Slate • Oct. 22, 2019

From the third floor overlook, she stands next to a gigantic faceted Fresnel lens, used in lighthouses.

From Washington Times • Jan. 2, 2017