| 摘要 |
In order to produce a Fresnel lens spotlight whose emitted light beam has an adjustable aperture angle, having a preferably ellipsoid reflector, a lamp and at least one Fresnel lens, which has a more compact form and is thus not only more space-saving but is also lighter than the conventional Fresnel lens spotlight, a lens with a negative focal length and a virtual focal point is used as the Fresnel lens.
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