Abstract
Street lighting lanterns incorporating tubular fluorescent lamps often have a reflector system whose design is derived from the properties of the parabola. Because of the large angle subtended by the lamp at the surface of the reflector, the provision of a peak luminous intensity in a direction 70–80 deg. from the vertical generally results in a large amount of light being reflected above the horizontal.
An alternative to the parabola as a basis for a reflector system is described which avoids this difficulty. A differential equation defining suitable contours is derived and a solution to this equation is given.
The application of curves defined by these equations to practical reflector systems is then discussed.
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