The illuminance cone is used to illustrate the beam patterns of rotation-symmetrical luminaires (OPTOS downlights and spots). It represents the light bundle emitted at One-half-peak Divergence or Half-value Angle. This is the term used for the aperture angle at which maximum Luminance is halved (cf. Polar Diagram). In general the maximum value is achieved at a beam angle of 0°. In this context, DIN 5037, Part 4 describes one-half-peak divergences of up to 5° as ultra-narrow beam, from 5° to 10° as narrow-beam, from 10° to 50° as wide angle and above 50° as extra-wide angle.
The illuminance cone diagram also shows mean illuminance available within an area delimited by the half-value angle (light cone diameter) for various mounting heights (cf. Height above Working Plane). These data are used for approximative lighting planning calculations.
The illuminance cone diagram also shows mean illuminance available within an area delimited by the half-value angle (light cone diameter) for various mounting heights (cf. Height above Working Plane). These data are used for approximative lighting planning calculations.
