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Parabolic reflector

About: Parabolic reflector is a research topic. Over the lifetime, 3375 publications have been published within this topic receiving 30735 citations. The topic is also known as: paraboloid reflector & paraboloidal reflector.


Papers
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Patent
02 Jan 1974
TL;DR: In this article, a reflector-heat sink panel with myriads of miniature parabolic mirrors and conductive heat collectors and a flattened focusing mirror is introduced, which is a thin multistep mirror which functions as a regular parabolic mirror with a relatively large focal length.
Abstract: The present invention, introduces (i) a reflector-heat sink panel with myriads of miniature parabolic mirrors and conductive heat collectors and (ii) a flattened focusing mirror. The reflector-heat sink panel has a transparent cover, a multiplicity of miniature parabolic mirrors to focus the Sun's rays into their respective focal regions which also serve as heat sink regions. For an efficient operation, heat generated in these regions is collected and transmitted to a heat transfer surface which is located on the backside relative to the mirror surfaces by conductive heat collecting branches and a conductive main and is transmitted to a heat absorbing medium. Another convenient way is to use the space separating the transparent cover and the mirror surfaces as a conduit to carry a heat absorbing medium and use the surfaces of conductive heat collecting branches and the mirror surface as the heat transfer surface of transmitting heat energy to the heat absorbing medium. Converging lens-heat sink panels which do similar job as that of reflector-heat sink panels are also described. The flattened focusing mirror is a thin multistep mirror which functions as a regular parabolic mirror with a relatively large focal length. What a flattened focusing mirror is to a regular parabolic mirror is about what a Fresnel lens is to a regular lens. method, The invention also introduces a multiple focusing method of accomplishing an even higher degree of concentrating solar energy and ways of storing heat energy at a relatively high temperature. In the multiple focusing method a wide band of the Sun's parallel rays is first reduced into a narrow band of parallel and concentrated rays, which is then reconverged into concentrated bands and harvested by a narrow reflector-heat sink panel. In another embodiment, several narrow bands of parallel and concentrated rays are formed and combined into a large band of parallel and concentrated rays and refocused into a set of very highly concentrated rays.

107 citations

Patent
16 Jan 2002
TL;DR: An optical wireless transceiver (200) for communicating broadband signals through free space includes an input, a regenerator (206), a splitter (218) and a plurality of lasers in transmitter modules (225).
Abstract: An optical wireless transceiver (200) for communicating broadband signals through free space includes an input, a regenerator (206), a splitter (218) and a plurality of lasers in transmitter modules (225). A very fast (low f-number) optical receiver module includes a reflector, preferably a Mangin mirror or parabolic reflector with field corrector, aligned with an input aperture. A photodiode receives the signal from the reflector for subsequent demodulation. The transceiver provides signal regeneration and switchable data rates. Connections are made to optical or electrical digital inputs and outputs bearing signals of various protocols.

107 citations

Patent
10 Apr 2006
TL;DR: In this article, various optical techniques for obtaining a specified light output from an LED source are described, such as using a parabolic reflector surrounding an LED or LED array to create a collimated beam, and the light exit opening of the reflector is defined by a reflective disc with an opening of a desired size.
Abstract: Various optical techniques are described for obtaining a specified light output from an LED source. One technique uses a parabolic reflector surrounding an LED or LED array to create a collimated beam, and the light exit opening of the parabolic reflector is defined by a reflective disc with an opening of the desired size. Any generated light that is outside of the opening is reflected back into the parabolic reflector and re-reflected until the light exits the opening. For mixing different light colors from different LEDs or energized phosphors, a mixing tunnel is used. The mixing tunnel includes angled dichroic mirrors or angled polarizer mirrors that selectively reflect and pass selected colors or polarizations of light to a single output port of the mixing tunnel. Efficient and compact ways to energize phosphors are also described. Other optical techniques are also described.

104 citations

Journal ArticleDOI
TL;DR: In this paper, the authors derived the radiation integral for a doubly curved offset reflector antenna illuminated by an arbitrary source using the Jacobi-Bessel series to evaluate the Fourier transforms.
Abstract: The physical optics approximation is employed to derive the radiation integral for a doubly curved offset reflector antenna illuminated by an arbitrary source. A novel procedure is presented for expressing the radiation integral in terms of a summation of Fourier transforms of an "effective" aperture distribution which includes the effect of the curvature of the surface. The Jacobi-Bessel series is used to evaluate the Fourier transforms. The vector nature of the far-field pattern is studied by evaluating its three Cartesian components in a unified fashion. The rapid numerical evaluations of the expressions obtained are demonstrated via extensive test cases. In particular, the scattering characteristics of symmetric and offset parabolic, spherical, and shaped reflectors are studied in detail, and comparisons are made with other available data.

104 citations

Patent
21 Nov 2003
TL;DR: In this paper, a composite reflecting surface for a linear LED array incorporates a truncated circular parabolic reflector surrounding each LED and a trough axially above the circular paraboloid reflectors defined between parallel longitudinal reflecting surfaces.
Abstract: A composite reflecting surface for a linear LED array incorporates a truncated circular parabolic reflector surrounding each LED and a trough axially above the circular parabolic reflectors defined between parallel longitudinal reflecting surfaces. The short circular parabolic reflectors collimate wide angle light from the LED into a direction parallel to the LED optical axis. The longitudinal reflecting surfaces are linear parabolic surfaces altered to improve the vertical spread of the light radiation pattern. Longitudinal convex ribs project inwardly from the basic linear parabolic shape. The convex shape of the ribs “sprays” the light incident upon it in a vertically spread pattern. The composite reflecting surface makes use of light from a linear array of LEDs that would otherwise be wasted.

103 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202338
202286
202168
202098
2019136
2018128