Fresnel lens
![First-order lighthouse Fresnel lens, on display at the Point Arena Lighthouse Museum, Point Arena Lighthouse, Mendocino County, California](/Images/godic/202501/14/Fresnel_Lens_at_Point_Arena_Lighthouse_Museum3442.jpg")
![How a spherical Fresnel lens collimates light1: Cross section of a spherical Fresnel lens2: Cross section of a conventional spherical plano-convex lens of equivalent power](/Images/godic/202501/14/Fresnel_lighthouse_lens_diagram3442.png")
![1 Cross section of a spherical Fresnel len, 2 Cross section of a conventional spherical lens](/Images/godic/202501/14/Fresnel_lens.svg3442.png")
![Close-up view of a flat Fresnel lens shows concentric circles on the surface](/Images/godic/202501/14/Flat_flexible_plastic_sheet_lens3442.JPG")
A Fresnel lens (/freɪˈnɛl/ fray-NEL or /ˈfrɛznəl/ FREZ-nəl) is a type of compact lens originally developed by French physicist Augustin-Jean Fresnel for lighthouses.
The design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design. A Fresnel lens can be made much thinner than a comparable conventional lens, in some cases taking the form of a flat sheet. A Fresnel lens can capture more oblique light from a light source, thus allowing the light from a lighthouse equipped with one to be visible over greater distances.