Semiconductor Light Sources-the Revolution in Optoelectronics

摘要

In the 20th century there were two main types of light sources: incandescent lamps and gas-discharge lamps, among which the leading place is occupied by luminescent lamps. In everyday life the incandescent lamps of power 15-300 W are traditionally the most common. The efficiency of incandescent lamps does not exceed 5%, because the major part of the electric power is wasted for heating. The lifetime of incandescent lamps amounts to 1500 hours. Luminescent lamps, despite having the efficiency almost 6 times as high as that of incandescent lamps, are not so widely used in lighting the living quarters because their light is inadequately perceived by human eye and they are expensive. Halogen lamps may compete with incandescent lamps, however, their mass use is limited by a number of reasons, including the high cost. Luminescent lamps are applied for lighting of public and industrial premises, such as medical and educational institutions, terminals, establishments, shops, etc.