File:Contre miroir.png

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Contre_miroir.png (391 × 209 pixels, file size: 4 KB, MIME type: image/png)

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Description
Français : Projecteur à miroir parabolique et contre-miroir sphérique

Sans contre-miroir (figure de gauche), une partie des rayons de l'ampoule sortent par l'ouverture du miroir sans être dévié, ils ne contribuent pas au faisceau parallèle. projetté sur un mur, on obtient un disque lumineux entouré d'un halo dont l'intensité s'estompe avec l'éloignement.

Avec un contre-miroir (figure de droite, le contre-miroir sphérique récupère les rayons qui s'échappaient par devant et les rabat sur le miroir parabolique. On n'a plus de halo, tous les rayons contribuent au faisceau parallèle, mais on a une tache sombre au milieu.

Les miroirs sont en réalité beaucoup plus tronqués, ils n'enveloppent pas l'ampoule.

Auteur : Christophe Dang Ngoc Chan, réalisé avec un programme de dessin vectoriel

Licence GFDL

Christophe Dang Ngoc Chan
Date 22 January 2004 (original upload date)
Source Transferred from fr.wikipedia to Commons by Bloody-libu using CommonsHelper.
Author The original uploader was Cdang at French Wikipedia.

Licensing

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GNU head Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License.
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This licensing tag was added to this file as part of the GFDL licensing update.

Original upload log

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The original description page was here. All following user names refer to fr.wikipedia.
  • 2004-01-22 14:10 Cdang 391×209× (4595 bytes) Contre-miroir sphérique

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Date/TimeThumbnailDimensionsUserComment
current15:39, 9 August 2012Thumbnail for version as of 15:39, 9 August 2012391 × 209 (4 KB)File Upload Bot (Magnus Manske) (talk | contribs)Transfered from fr.wikipedia by User:Bloody-libu using CommonsHelper

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