Plane light source unit and radiant heating furnace including same

A radiant heating furnace comprising:

• at least one plane light source unit arranged along a boundary of an irradiation space and having means for evenly distributing heat comprising a plurality of halogen lamps, each of said halogen lamps comprising an elongated sealed tubular body defining a longitudinal axis, said body including a tubular wall portion and sealed end portions, and a filament formed of alternating non-luminous portions and luminous portions in the tubular body along the longitudinal axis;
• a mirror positioned in proximity to said halogen lamps;
• side mirrors spaced from one another and arranged along the irradiation space generally orthogonal to said plane light source unit;
• a cooling system adapted to cool the plane light source unit;
• and
• lamp supports mounted on said side mirrors, wherein said halogen lamps are disposed close to each other with the longitudinal axes thereof parallel and lying in a common plane, each of said lamps being supported at its tubular wall portion adjacent to its sealed end portions by said lamp supports, said sealed end portions being exposed and uncovered;
• and
• said cooling system includes a water cooling system comprising water channels extending through said side mirrors, said water channels being in communication with a cooling water supply system.