SEARCHLIGHT WITH FRESNEL LENS Russian patent published in 2007 - IPC F21S8/00 F21L4/00 F21V5/04 F21V14/02 

FIELD: light engineering.

SUBSTANCE: searchlight comprises Fresnel lens with controlled aperture of output beam, elliptical reflector, lamp, and at least one Fresnel lens. The distance between the Fresnel lens and reflector can be changed depending on the distance between the lamp and reflector according to the controlled angle of the aperture of the searchlight beam. The Fresnel lens has circular diffusion screen mounted at the center of the lens. The Fresnel lens and the screen define a system for shifting light, which allows the fraction of the diffused light to be changed, and the Fresnel lens has real point of focusing that can be set in coincidence with the focusing point of the reflector. The reflector focusing point is located far from the reflector. The Fresnel lens represents a flat-convex collecting lens and has double lens with chromatic-corrected projection properties. The coating of the Fresnel lens has a system of dielectric interference layer that changes the spectrum of the light passing through it. The auxiliary reflector is interposed between the Fresnel lens and reflector.

EFFECT: enhanced efficiency.

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