The Collaborative International Dictionary
Fresnel lens \Fres`nel" lens"\ [See Fresnel lamp.] (Optics) See under Lens.
Lens \Lens\ (l[e^]nz), n.; pl. Lenses (-[e^]z). [L. lens a lentil. So named from the resemblance in shape of a double convex lens to the seed of a lentil. Cf. Lentil.] (Opt.) A piece of glass, or other transparent substance, ground with two opposite regular surfaces, either both curved, or one curved and the other plane, and commonly used, either singly or combined, in optical instruments, for changing the direction of rays of light, and thus magnifying objects, or otherwise modifying vision. In practice, the curved surfaces are usually spherical, though rarely cylindrical, or of some other figure. [1913 Webster] Lenses
Note: Of spherical lenses, there are six varieties, as shown in section in the figures herewith given: viz., a plano-concave; b double-concave; c plano-convex; d double-convex; e converging concavo-convex, or converging meniscus; f diverging concavo-convex, or diverging meniscus.
Crossed lens (Opt.), a double-convex lens with one radius equal to six times the other.
Crystalline lens. (Anat.) See Eye.
Fresnel lens (Opt.), a compound lens formed by placing around a central convex lens rings of glass so curved as to have the same focus; used, especially in lighthouses, for concentrating light in a particular direction; -- so called from the inventor.
Multiplying lens or Multiplying glass (Opt.), a lens one side of which is plane and the other convex, but made up of a number of plane faces inclined to one another, each of which presents a separate image of the object viewed through it, so that the object is, as it were, multiplied.
Polyzonal lens. See Polyzonal.
Wikipedia
A Fresnel lens ( or ) 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.
Usage examples of "fresnel lens".
Aft, he could see deck personnel and officers checking the arrestor cables and gathering in front of the Fresnel lens system.
The carrier was resolving itself into its shape, the familiar island jutting above the flight deck, the Fresnel lens now a pinprick of light off to his left.
The acknowledgment had just passed from the Air Boss to the Landing Signals Officer, or LSO, standing at his station just below the Fresnel lens.
How the hell was he supposed to spot the Fresnel lens that was supposed to help guide his final approach?
If the pilot is high of the glide path, he sees the top Fresnel lens.
To port, the bull's-eye of tf tfce Fresnel lens lit up red as the LSO triggered the pickle ^(twitch te held in one hand.
We can get square Fresnel lens panels commercially, and they can generate a lot of heat -- up to 3,000 degrees Fahrenheit.
We can get square Fresnel lens panels commercially, and they can generate a lot of heat—.
We can get square Fresnel lens panels commercially, and they can generate a lot of heat&mdash.
It was like looking at the young Victoria through a big Fresnel lens.
It was also pitch black save for the rain-smeared gleam of flight-deck acquisition lights and the glow from the big Fresnel lens apparatus aft and to port, where the Landing Signals officer and his crew were already talking the next aviator down.
The tiny Fresnel lens showed a small black woman clad entirely in white standing on the other side.
Thick wires, in insulating sheathes of hand-knit asbestos, twist out of the jar and into the business end of the galvanick lucipher: a copper salad bowl whose mouth is closed off by a Fresnel lens like the ones on a lighthouse.
Overhead, a Fresnel lens two meters square focused the canopy's diffuse sunlight on the desk's occupant.
I watched Piet as he spitted the beetle under a Fresnel lens held by Hammurabi.