|
The angular dimension of the cone of light from reflectorized lighting devices encompassing the central part of the beam out to the angle where the intensity is 50% of maximum. The beam angle sometimes called "beam spread" is often an optional item for LED lighting devices. For example: Spectra IV offers narrow and wide beam angles of 26 and 80. |
|
It is typically expressed in the measure of luminous intensity of a source in a given direction. The term has been retained from the early days of lighting when a standard candle of a fixed size and composition was defined as producing one candela in every direction. A plot of intensity versus direction is called a candela distribution curve and is often provided for reflectorized lighting devices and for luminaires with a lighting device operating in them. |