Fresnel lens

Definitions

  • WordNet 3.6
    • n Fresnel lens lens composed of a number of small lenses arranged to make a lightweight lens of large diameter and short focal length
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Webster's Revised Unabridged Dictionary
    • 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.
    • Fresnel lens (Optics) See under Lens.
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Etymology

Webster's Revised Unabridged Dictionary
See Fresnel lamp

Usage


In news:

Holographic and Fresnel-lens technologies make a bold statement.
The new focusable Sola 4 features a 4-inch Fresnel lens and employs Litepanel's LEDs for soft light quality in 5600°K daylight color balance.
That's the hope of the Port Hueneme Cultural Heritage Board, which Monday agreed to let the Fresnel lens fade from its longtime role as beacon of light .
The Kebleshes launched a search to locate a light source using the beacon effect of a Fresnel lens to make the illumination source of their lighthouse authentic.
The Cape Mendocino light Fresnel lens PHOTO BY BARRY EVANS.
The Cape Mendocino light is a "first order" Fresnel lens, meaning that it's one of the largest ever made, with a focal length (horizontal distance from light to lens) of about three feet.
A Fresnel-style lens condenses the light from each LED in the array and then projects it in the form of individual beams and spots, similar to a standard moonflower but with more control.
Robe's new ColorWash 575AT Zoom has all the features of the ColorWash 575AT with the additional enhancement of a very smooth motorized linear zoom , ranging from 8º to 50º with a fresnel lens fitted as standard.
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In science:

The focal module is composed of a diaphragmed small telescope used as ”field lens”, a small cophased diverging Fresnel Zone Lens (FZL) that cancels the dispersion and a detector.
Fresnel Interferometric Imager: ground-based prototype
In this paper, we describe the experimental setup, different designs of the primary Fresnel array, and the cophased Fresnel Zone Lens that achieves rigorous chromatic correction.
Fresnel Interferometric Imager: ground-based prototype
In the first part of this paper, we describe the elements constituting the prototype: an improved transmission binary Fresnel array, and the design of the chromatic corrector with a diverging Fresnel Zone Lens, which is a small but essential element in the focal optics.
Fresnel Interferometric Imager: ground-based prototype
Therefore, a solution to correct for the chromatism induced by the Fresnel Array placed in A1 is to place in a pupil plane A2 a Fresnel Zone Lens with an equal number of zones N2 = N1 , used at its order -1 and whose diameter is that of the imaged Fresnel Array.
Fresnel Interferometric Imager: ground-based prototype
Although theoretically perfect, this correction is bandpass limited to ∆λ/λ ≃ 30% in practice, mainly due to the blaze angle mismatch of the secondary Fresnel lens with non optimal wavelengths (see below).
Fresnel Interferometric Imager: ground-based prototype
We have made numerical simulations by Fresnel propagation of the diverging FZL alone and of the complete prototype, including the primary array, field optics, zero order blocking mask, corrector blazed FZL with its discretization due to the manufacturing process, and final converging lens.
Fresnel Interferometric Imager: ground-based prototype
We have taken into account all its optical elements: the Fresnel array, field lens, zero order mask, blazed FZL with its manufacturing charcacteristics and the final achromatic doublet.
Fresnel Interferometric Imager: ground-based prototype
In the second module, field optics (2) form a pupil plane (3), where a diverging cophased Fresnel Zone Lens (FZL) is placed.
Fresnel Interferometric Imager: ground-based prototype
The focal module is composed of a Maksutov telescope used as a field lens, a cophased diverging Fresnel diffractive lens situated in the pupil plane, and an achromatic doublet next to that pupil plane.
Fresnel Interferometric Imager: ground-based prototype
Optical paths in a blazed diverging Fresnel zone lens (FZL) illustrated for 3 zones.
Fresnel Interferometric Imager: ground-based prototype
Numerically simulated efficiency as a function of wavelength for a fused silica cophased Fresnel Zone Lens, optimized for λ= 600 nm.
Fresnel Interferometric Imager: ground-based prototype
The prototype reaches limited by diffraction for all these wavelengths, confirming the efficiency of the chromatic correction and the blazed diverging Fresnel zone lens design.
Fresnel Interferometric Imager: ground-based prototype
The photomultipliers were divided into ten modules, each of them was equipped with a 0.1 m2 Fresnel lens.
Air Fluorescence Relevant for Cosmic-Ray Detection - Summary of the 5th Fluorescence Workshop, El Escorial 2007
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