page_title: Sulfur lamp
section_title: Secondary reflectors
hierarchical_section_title: Sulfur lamp / Light distribution systems / Secondary reflectors
caption_attribution_description: Secondary reflector above sulfur lamp at Midlanda Airport in Sweden.
context_page_description: The sulfur lamp is a highly efficient full-spectrum electrodeless lighting system whose light is generated by sulfur plasma that has been excited by microwave radiation. They are a particular type of plasma lamp, and one of the most modern. The technology was developed in the early 1990s, but, although it appeared initially to be very promising, sulfur lighting was a commercial failure by the late 1990s. Since 2005, lamps are again being manufactured for commercial use.
context_section_description: A secondary reflector is a structure with a mirrored surface placed directly into the path of the beam of light as it exits the parabolic primary reflector of the lamp.  A secondary reflector can have a complex geometry which allows it to break up the light and direct it to where it is desired.  It can spotlight an object or spread out the light for general illumination.
  At Sundsvall-Härnösand Airport near Sundsvall, Sweden, airfield lighting is provided by sulfur lamps mounted on towers 30 metres tall.  The lamps are directed upward and shine their light onto wing-shaped secondary reflectors that spread the light out and direct it downward.  In this way, one lamp can illuminate an area 30 by 80 metres (100 by 260 ft).
  At the headquarters of DONG Energy, an energy company in Denmark, a single sulfur lamp directs its light onto numerous specular reflectors and diffusers to illuminate the entrance hall as well as several sculptures outside of the building.
  At the entrance to University Hospital in Lund, Sweden, secondary reflectors on the ceiling are clad with highly reflective films, but shaped so as to avoid any glare.  Moreover, since these films have a microprismatic surface structure that splits up the beams, the risk of glare problems is further reduced.  The fact that the reflectors move the light source far away from the eye of anyone who would happen to look into them helps to further eliminate glare problems.
caption: Sulfur lamp with reflectors
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