FRESNEL-LENS SEARCHLIGHT Russian patent published in 2007 - IPC F21S8/00 F21S2/00 F21V5/04 

FIELD: optics.

SUBSTANCE: proposed Fresnel-lens searchlight whose light beam is radiated at adjustable aperture angle has reflector, lamp, and at least one Fresnel lens. The latter is essentially negative focal length lens and, hence, it is negative lens with virtual focal point. Searchlight is designed for superposing focal point distant from reflector onto virtual focal point of Fresnel lens. Mentioned point of reflector is superposed on virtual focal point of Fresnel lens in searchlight position forming quasi-parallel path of beam. It is concave-concave negative lens incorporating duplex lens with chromatically corrected display characteristics. Searchlight Fresnel lens has circular integrated dissipating glass disposed at center of Fresnel lens thereby forming light mixing system that varies some fraction of dissipated light relative to fraction of diametrically and optically reflected light, that is, light mixing is function of Fresnel-lens searchlight position. Searchlight ellipsoidal reflector is made of metal or transparent, preferably dielectric, material in the form of glass and/or plastic. Fresnel lens is covered with a number of dielectric interference layers which function to vary spectrum of light passed through lens. Auxiliary reflector is disposed between Fresnel lens and main reflector.

EFFECT: reduced space requirement and mass compared with prior-art searchlights of this type.

19 cl, 6 dwg