Fresnellens

Fres·nel lens (frə-nĕlʹ) Prisms that make up a Fresnel lens bend and magnify light rays, creating a single, concentrated beam of light. Precision Graphics n.

A thin optical lens consisting of concentric rings of segmental lenses and having a short focal length, used primarily in spotlights, overhead projectors, and the headlights of motor vehicles.

  [After Fresnel, Augustin Jean.]

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