Illuminance Characteristics of Energy-saving Luminaire with White-Light-Emitting Diode and a Solar-cell and Battery System for Street Lighting

Abstract

The illuminance characteristics of a next-generation energy-saving luminaire for street lighting is described. It consists of white-light-emitting diodes (LEDs) and a solar-cell and battery system. A prototype luminaire was constructed of two LED light sources, each of which with a total of 700 units of 10-cd-class white LEDs. The illuminance is normally 80lx. When a person approaches within 2 m of the luminaire, a pyroelectric motion-sensor senses the situation and the illuminance is increased to about 660 lx. This is about 50 times brighter than a white incandescent lamp. The luminous efficacy of the white LED array source was estimated to be approximately 451m/W at a forward-current of 1mA. Field testing showed that this white LED lighting system did not suffer serious deterioration in either it's brightness or electric circuit over a period of one year.