Light distributions
Light distributions

Lighting technology clearly explained. By HELLA.

At this point we would like to provide you with some information on light distribution systems.

More on the light distribution of auxiliary headlamps

Light distribution refers to the spatial distribution of luminous intensity. This is clearly illustrated by the Isolux diagrams in which various light distributions are compared. The greatest illumination intensity is indicated in the Isolux diagrams by a red-orange color and as the distance from the light source increases, the illumination intensity also decreases and changes accordingly from yellow to green to blue. Different headlights are required, depending on the purpose: Fog lamp beams are wide for example, but not far-ranging in order to extensively eliminate reflection by mist droplets. Spotlights emit a far-ranging light. The innovative ELIVER tool by HELLA is an excellent way to directly compare the different light distributions of headlamps.


Lux is a unit of illuminance that specifies the luminous flux which strikes a certain surface as it travels from the light source. To illustrate an example from everyday life: An office workplace should be illuminated with at least 500 lux, and the human eye can still read a newspaper without any problems with an illumination of 1 lux. The values under the so-called "lux bar" in light distribution diagrams indicate where the corresponding illuminance is achieved.


The reference number, also referred to as the ref. value, refers to the high-beam headlamp. According to the ECE regulation that came into force in 2009, the sum of the reference numbers of all (high-beam) headlamps mounted on one vehicle must not exceed 100. In this case, the two values of the standard high beams (left and right headlamps) are counted as well as the values of other mounted high-beam headlamps. You can find the reference number of our HELLA high-beam headlamps in the catalog and also on the E type-test mark which is mounted on the headlamps. We recommend that you make a note of the reference numbers of your auxiliary headlamps in the HELLA reference number pass. You can also find detailed information in our explanatory PDF.


When you opt for HELLA, you opt for uncompromising quality. Every day we strive to make our lighting solutions even better and more reliable. As a result of our unrelenting innovative drive, we are one of the leading suppliers in many areas of the automotive and lighting industry, and often even assume a pioneering role, especially in the area of LED technology. Visit our product area to find out more about our innovative LED solutions or use the ELIVER tool to compare and contrast the LED technology with other lighting technologies.


We are committed to implementing quality in practice. We do so by making continuous improvements in response to new developments based on our outstanding quality management. And by carrying out daily checks as stringently and carefully as possible on each series and product – often surpassing the legal requirements. This is ensured by using state-of-the-art technology, sophisticated test methods and, last but not least, the expectation to be better than everybody else. One of the best known examples is our light testing facility at our headquarters in Lippstadt, the only one of its kind in Europe. Here, not only light distributions, but also the high quality expectations of HELLA can be experienced.

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Light distribution poster

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