100 mm

IntroductionThe most important light variables in signaling technology are:• light intensity• luminous fl ux• illumination intensityLight intensity is measured in Candela [cd].The light intensity is the radiation power of a light source per dihedral angle, weighted with the spectral sensitivityof the eye. The directional dependence of the luminous fl ux is represented. This is particularly important in signaltechnology, since it is not about illuminating a room, but rather about the directed transmission of light to theobserver.light intensity [cd] = luminous flux [lm] / dihedral angle [sr]For example, the light intensity of a household candle is around 1 cd.Luminous fluxΦ is expressed in Lumen [lm].The luminous fl ux is a measure of the entire visible radiation that is radiated in all directions from a source of lightand, as opposed to light intensity, is not directionally dependent.Illumination intensity is expressed in Lux [lx].The illumination intensity describes the amount of the luminous fl ux that strikes a given area. It is the quotient ofluminous fl ux and area.illumination intensity [lx] = luminous flux [lm] / area A (m 2 )The illumination intensity is inversely proportional to the square of the distance. A doubling of the distance thereforeresults in the illumination intensity being reduced to one quarter.Light intensityLuminous fl uxLight densityIllumination intensity22