US Patent 9897305 Controlled environment light fixture

Controlled environment light fixture configurations include an LED light source. The light fixtures can be installed and removed from below the ceiling. The light fixture can be installed and removed without opening the lens frame of the light fixture. The light fixture includes a sealed housing and seals to the ceiling when installed. The light fixtures are provided in exterior dimension sizes that allow the fixtures to be installed in a variety of controlled environment ceilings in recessed configurations. The lower surface exposed to the controlled environment is free of welds and grinds in order to provide a corrosion resistant surface.