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.

Compact led light engine with reflector cups and highly directional lamps using same

Abstract: A light engine comprises a plurality of light emitting diode (LED) devices arranged in a plane and a corresponding plurality of reflector cups wherein each LED device is disposed in a corresponding reflector cup and wherein the light engine does not include either a diffuser or a light mixing cavity. A directional lamp comprises the aforesaid light engine and an imaging lens arranged to generate an image of the light engine at about infinity. The directional lamp may further include a collecting reflector (for example, a conical, parabolic, or compound parabolic reflector) extending between a relatively narrower entrance aperture at which the light engine is disposed and a relatively wider exit aperture at which the imaging lens is disposed. The imaging lens may be arranged to generate a defocused image of the light engine at about infinity to soften the beam edge.

Principles Of The Fixed Mirror Solar Concentrator

Abstract: A new concept for a fixed-mirror solar concentrator is described. The fixed, stepped surface of the proposed cylindrical mirror is designed to produce a sharply focused line image regardless of the incident sun direction. This is in contrast with the severe off-axis aberration (hence, poor concentration factor) of a parabolic mirror for all sun directions other than on-axis. It is shown that 1) the heat absorber follows a circular path to remain in the focus as the sun moves, 2) the annual light losses from self-shadowing of the "stepped structure of the mirror surface can amount to less than %in for appropriate mirror orientation, 3) by facing the mirror in a southerly direction in the northern hemisphere) , the winter deficit in sun input can be significantly compensated, and 4) practical concentration factors of around 50 can be achieved with a single stage of concentration, 80 with a second stage of concentration.© (1977) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Experimental verification of the analysis of umbrella parabolic reflectors

Abstract: Gored umbrella parabolic reflectors with symmetric aperture illumination have been treated analytically in a recent paper. This communication extends the analysis to the case where the primary feed illumination is not symmetric, because real primary feeds usually have unequal E - and H -plane beamwidths. The gore loss and the shift in the defocusing curve obtained using the modified gain expression are in excellent agreement with values measured for a smooth parabolic reflector and a gore parabolic reflector of the same diameter.

Null test of an off-axis parabolic mirror. II. Configuration with planar reference wave and spherical return surface

Abstract: This paper complements our previous study on testing a 25.4 mm diameter diamond-turned 90 masculine off-axis commercial-quality parabolic mirror with a spherical test wave in a phase-shifting Fizeau interferometer (Opt. Express 17, 3196-3210 (2009). In this study I reverse the optical system and use the Fizeau interferometer with a planar reference surface, auxiliary components, and the surface of the transmission sphere as a reflecting spherical return surface. As in the previous paper, I present a description of the necessary steps for alignment and measurement validation. The reversal of the optical system, and associated co-ordinate systems, necessitates some changes of hardware and analysis that provide insight into the underlying symmetries, and may prove useful in a wider context.