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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
17 Jan 1984
TL;DR: In this article, a headlamp unit having a high intensity discharge lamp disposed at about the focus of a parabolic reflector and an incandescent lamp was shown to have been disposed at the same position.
Abstract: A headlamp unit having a high intensity discharge lamp disposed at about the focus of a parabolic reflector and an incandescent lamp disposed at about the focus of a parabolic reflector.

23 citations

Journal ArticleDOI
TL;DR: A parabolic liquid mirror obtained by the rotation of a mercury bath around a vertical axis has been built and its optical surface characteristics measured to demonstrate that it can be used in optical shop testing as a reference surface.
Abstract: A parabolic liquid mirror obtained by the rotation of a mercury bath around a vertical axis has been built and its optical surface characteristics measured to demonstrate that it can be used in optical shop testing as a reference surface. A linear Hartmann test allowed us to check that the focal length is well related to the rotation velocity, following the theory, and that no spherical aberration is present, as assumed by previous authors. The spherical aberration has been found to be smaller than λ/50 at 633 nm. An interferometric test of the mirror compared with a null lens gave information about the quality of the optical surface for which the rms wave-front error, when the random errors are averaged, is ~λ/25. Because modifying the mirror diameter is cheap and fast and adjusting its focal length within a large range is straightforward, the parabolic liquid mirror can become a highly adaptable tool in optical metrology. In particular, it can be used in optical shop testing as a reference surface to test null correctors, to check any system developed to control the shape of large parabolic or quasiparabolic top-quality solid-state mirrors, or to make holographic references of such surfaces.

23 citations

Patent
06 Aug 2015
TL;DR: In this paper, the authors proposed a method to construct or repair a 3D object (36) by using a parabolic mirror-like formed device, where an inner surface (42) of the parabolic reflector (24, 34) is oriented concave to the material layer (22) and the laser means (18) above and / or disposed outside of a building platform (14) such that the generated laser beam (20, 28, 30, 32, 40, 44, 46, 48, 50) via a beam deflection by means of the reflected
Abstract: The invention relates to a device (10) for the manufacture or repair of a three-dimensional object (36) comprising at least one installation space (12) for a layer-wise, successive solidification of at least a solidifiable material (16) in predefined areas for layerwise construction of the three-dimensional object (36) or layered repair of individual portions of the three-dimensional object (36) within the installation space (12); and at least one laser device (18) for generating at least one laser beam (20, 28, 30, 32, 40, 44, 46, 48, 50) by means of which a material layer (22) is locally fusible to an object layer and / or sinterability. The device (10) comprises at least one parabolic mirror (24, 34) or at least one parabolic mirror-like formed device, wherein an inner surface (42) of the parabolic mirror (24, 34) or the parabolic mirror-like device is oriented concave to the material layer (22) and the laser means (18) above and / or disposed outside of a building platform (14) such that the generated laser beam (20, 28, 30, 32, 40, 44, 46, 48, 50) via a beam deflection by means of the parabolic reflector (24, 34) or the parabolic mirror-like device on the material layer (22) is incident, wherein a projection (P1, P2) of the parabolic mirror (24, 34) or the parabolic mirror-like device is larger or smaller than at least one building area (B) of the building platform (14) which is designed for applying the material (16). The invention further relates to a method of manufacture or repair of a three-dimensional object (36).

23 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the effect of circumsolar radiation on the optimal performance of a coupled parabolic dish and a Stirling heat engine, referred to as the Dish/Stirling system.

23 citations

Journal ArticleDOI
TL;DR: The stress distributions in the mirror when lifted by a central lifter and when resting on its axial flotation system are shown and a comparison is made between the results using classical flat-plate theory and the finite-element models.
Abstract: Large finite-element mathematical models are developed to calculate the deformations induced by the supports of a 4.2-m aperture 3.2-focal ratio primary mirror of an optical telescope. It is supported axially on three rings of pneumatic cylinders and radially by a system of transverse level weights, an arrangement only possible in a telescope that uses an altazimuth mounting. The stress distributions in the mirror when lifted by a central lifter and when resting on its axial flotation system are shown. A comparison is made between the results using classical flat-plate theory and the finite-element models.

23 citations


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