Directivity

What does "directivity" mean?

The Directivity describes how light from a light source is distributed throughout a space. It defines the spatial distribution of luminous intensity and significantly influences how a lamp produces its lighting effect. Depending on the design, optics, and position of the light source, a specific light pattern is created that is suitable for various applications.

Symmetrical radiation pattern

A basic distinction is made between symmetrical and asymmetrical beam patterns. A symmetrical beam pattern produces a uniform, rotationally symmetrical cone of light. This is typically the case with Spots, downlights, Recessed spotlights or specific Pendant Lights with a focused light source. This type is suitable for accent lighting, the targeted illumination of specific areas, or highlighting objects such as pictures on the wall.

Asymmetric radiation pattern

An asymmetric beam pattern, on the other hand, directs the light in a specific direction. It is used, for example, in Wall Sconces, floodlights, wall washers, or Outdoor spotlights used. Here, the light is directed specifically at surfaces, paths, or facades to achieve uniform surface illumination or functional lighting.

Beam Angle and Luminous Intensity

An important technical parameter in this context is the beam angle. The half-value angle describes the range within which the luminous intensity is at least 50 percent of the maximum value. The field angle defines the outer region of the light cone in which light is still perceptible. Both values provide information about how wide or narrow a light source’s beam is.

Implications for Lighting Design

The beam pattern therefore directly influences the lighting effect, the luminous intensity distribution, and the application range of a lamp. It is a key factor in the design of lighting systems and the selection of appropriate luminaires for different requirements.