Day Lighting
Written by Microsharp
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Utilising sunlight to illuminate the interior of buildings offers the potential of both energy saving and improved lighting environment. Microsharp has extensive experience of designing and manufacturing optical control films that are used in a number of Day Lighting technologies.  


The following structures are used in day lighting applications.



90/160 Light Control Film This film is simultaneously reflective or transmissive depending on the incident angle of the light. It is used in the production of  light tubes to tramsmit and out-couple light. view data sheet


70/30 Symmetrical Prism Film. This structure is used as a light deflecting film. Light incident at an acute angle is 'deflected' through the film by total internal reflection.  

Example Day Light Technologies


Light Redirection Systems


  It is important to make a distinction between light-redirecting systems designed principally to redirect beam sunlight versus diffuse skylight, although with any system, both sources of daylight are affected. Systems using direct sunlight are most effective on the south façade, and for practical geometric simplicity and efficiency, are designed based on seasonal variations in solar altitude. For moderate to hot climates, daylighting strategies must be integrated with solar gain control. 



Solar Tube Skylights



 A relatively recent development has been the market supply of skylight units where the opening (which includes efficient lens systems to collect light) is connected to a light tube (generally a mirrored metal tube) and to a light diffuser. The arrangement enables the skylight to be fitted to a roof point which is some distance and can be offset from the light distribution, at least to some degree. This enables downstairs room or rooms below attic spaces to be illuminated, so long as there is a route to house the continuous tube from skylight to light emitter.






Optical Light Piping Systems


  Optical films can be used to create a "prism light guide," a hollow structure that can efficiently transport large quantities of light. The facets are efficient total internal reflection mirrors which prevent light traveling down the guide from escaping. Very little light is absorbed by the pipe because light travels primarily in the air space within the hollow guide. And, because the guide is hollow, weight and cost factors are better than very large solid fibers.

Plastic Light Pipes

A number of newly developed systems seek to collect light using devices on the roof or other sunlit area which collect the light into flexible ‘light pipes’ – large fibre optic cables – which transport it to internal rooms within the building and then release the light in specially designed luminaires. In addition these luminaires can integrate artificial lighting and photosensors to ensure suitable lighting levels even at night or on cloudy days. In general these systems perform significantly better with direct sunlight compared to indirect light as direct light is easier to focus into the light pipes.