Domestic light pipe.
A light pipe is a device that gathers incoming sunlight sometimes using a solar tracking system. The light is concentrated using lenses or mirrors and is then transmitted to the interior of a building by special tubes. These may may be hollow shafts or ducts with reflective internal finishes, or may use fiber optic cable technology. A special luminaire is required to provide distribution of the light within the building.
A light pipe system depends heavily on the availability of sunlight. For critical tasks a back-up artificial light source is required.
Light pipes are becoming more and more popular, especially in areas that are mostly used during the day such as storage spaces and in domestic applications, e.g., in hallways. They are relatively inexpensive and easily retrofitted into an existing building.