While fluorescent lighting has enjoyed a widespread acceptance because of its efficiency in converting electrical energy to light energy and (for most applications) its favorable spectral emissions, there has remained a difficult and notorious problem in its use (in common with the corresponding use of incandescent lighting) which may be broadly categorized as "glare". In recent years, the problem of glare has been particularly manifested in work areas in which computer terminals are used and in which the glare is especially evident on the face of a cathode ray tube with which an operator may be working. Glare on a "computer screen" makes it difficult for the operator to see the information presented and therefore affects the operator's efficiency as well as contributing to operator eye strain. A similar effect is found in watching television in glare prone areas.
Numerous attempts have been made to control or eliminate the glare associated with fluorescent lighting fixtures. For example, downlight troffers and lenses have been employed in systems referred to as "low brightness". This approach did not correct the problem because direct light caused veiling reflections which, in turn, produced a reflection on the computer screen and therefore reduced the operator's "seeability". In a similar system, the lens was replaced with a parabolic louver, but reflections on the computer screen were still apparent. Suspended indirect lighting systems have been employed in which the light was directed onto the ceiling and reflected from the ceiling down to the work area. However, the light distribution produced a cosine curve with a distinctive "hot spot" on the ceiling centrally situated immediately above the luminaire. This distribution not only still resulted in a glare image on a computer screen within the work area, but also produced distracting and inefficient bright and dark lines across the ceiling.
Nonetheless, the use of indirect lighting is a sound preparatory approach to the problem of glare. Thus, those skilled in the art have appreciated that if an indirect fluorescent lighting system can be achieved in which such "hot spots" can be eliminated and uniform intensity of the light impinging across the surface of the ceiling is established, glare will be virtually eliminated. It is to this end that my invention is directed.
USPTO Backgrounds
USPTO Backgrounds