Rotational symmetry
The luminaire adopts a rotationally symmetrical reflector, and the symmetry axis of the light source with rotationally symmetrical light distribution is installed along the axis of the reflector. The iso-intensity curves of this kind of lamps are concentric circles. When this type of spotlight is illuminated by a single lamp, an elliptical spot is obtained on the illuminated surface, and the illumination is uneven; but when multiple lamps are illuminated, the spots are superimposed on each other, which can produce a satisfactory lighting effect. For example, hundreds of rotationally symmetrical floodlights are commonly used in stadiums, and they are installed on high towers around the stadium to obtain high illumination and high uniformity lighting effects.
Two symmetry
The iso-intensity curve of this type of projector has two symmetry planes. Most luminaires use symmetrical cylindrical reflectors, and linear light sources are installed along the cylindrical axis.
A symmetry
There is only one symmetry plane for the equal intensity curve of the lamp. The luminaire adopts an asymmetric cylindrical reflector or a symmetrical cylindrical reflector plus a grid that restricts light. The most typical is the sharp cut-off block retracted light distribution. This kind of light intensity distribution single lamp can obtain a more satisfactory illuminance distribution.
Asymmetrical
The iso-intensity curve of this kind of lamps has no symmetry plane. Mainly use mixed light lamps with different types of light sources with large differences in light intensity distribution and special lamps designed according to the specific lighting requirements of the place of use.
