With increasing interest in fuel conservation, the idea of employing sunlight for interior lighting has again become popular. While sunlight provides an inexpensive source of interior lighting, it has been difficult to manipulate this light so that a building interior will be provided with adequate light throughout the course of the day. Because the position of the sun in the sky is constantly changing throughout the day and through the different seasons, a means must be provided for capturing these rays regardless of their orientation on the horizon. Numerous schemes have been developed for tracking the path of the sun which required complex electro-mechanical tracking mechanisms. One such "active" scheme is disclosed in an article by M. Duguay and R. Edgar entitled "Lighting with sunlight using sun tracking concentrators" Applied Optics, volume 16 page 1444, May 1977, which employs an active tracking system. The disadvantage of such systems is that they are more costly to construct thereby reducing the economic advantage of solar lighting and discouraging its implementation in residential construction where sophisticated systems are too expensive and otherwise undesirable.
Current non-moving or "passive" solar collecting methods of admitting sun into an interior space are generally limited to glazing at the building envelope. Skylights and windows are very old techniques. The addition if frosted glass or plastic material used to scatter light has also been combined with these previous techniques to somewhat improve the effectiveness of prior passive methods but does not meet the need of providing sufficient light in the desired area throughout the daylight hours.
The present invention has overcome the deficiencies of the prior art by providing a passive means for increasing the angle at which incident light is accepted into a collector without physically tracking the movement of the sun.
USPTO Backgrounds
USPTO Backgrounds