LIGHTING SYSTEM AND LAMP WITH OPTIMAL FILAMENT PLACEMENT

摘要

A lighting system (10) for projecting a beam of light has a light source (14) and a concave reflector (12) having a central axis. The center of the light source (14) is located at a position other than at the focal point of the reflector (12), i.e. between the reflector surface and the focal point of the reflector (12) for an ellipsoidal reflector and forward of the focal point for a parabolic reflector. This placement provides a greater light output than is achievable by positioning the light source (14) at the focal point of the reflector (12). The preferred light source (12) is an improved lamp having an incandescent filament having a central linear helical portion aligned with a central axis of the reflector (12) and a peripheral helix portion around the central portion so as to concentrate the emission of light along and about the central axis of the filament.