The headlights of modern vehicles are fitted with lamps using various light sources: from halogen, through xenon, to LED lamps. This diversity causes a different set of so-called light and shadow border, which is one of the most important parameters when adjusting the headlights.
CONSTANT CONCLUSION …
In the case of halogen headlamps, which are used in dipped-beam headlamps, a constant 15-degree rise of the asymmetrical part of the light beam is used. This is currently the most common light distribution. In turn, the symmetrical part of the beam (on the side of the opposite lane) to the left of the vertical “zero line” runs just below the marked dashed line, i.e. the border of light and shadow. Thanks to this arrangement, the passing beam does not dazzle oncoming traffic. In addition, the asymmetrical light distribution increases its range and improves the visibility of the driver on his own lane and on the right roadside.
… OR VARIABLE?
It is different in the case of dipped beam headlights implemented with xenon headlights. In most cases, there is a constant, 12-degree rise of the asymmetrical part of the light beam, but in newer headlamp solutions this height is already variable and ranges from 12 to even 75 degrees. The feature of xenon headlights is the characteristic refraction of the asymmetrical part of the light beam, which however is not a defect. This type of characteristic is necessary because of the high light intensity: due to the refraction of the asymmetrical part of the light beam, the current intensity values specified in the relevant regulations arising from the Regulations of the European Economic Commission (ECE) are not exceeded. On the distribution of light from the left side of the vertical “zero line” (opposite lane), the symmetrical part of the light beam runs just below the dotted line (the border of light and shadow). The lights do not dazzle those in the opposite lane, however, the symmetrical distribution of light improves its range in its own lane and on the roadside.
IN LED AS IN XENONES
In headlights with LEDs installed, the rise of the asymmetrical part of the low beam is similar to the xenon system. The refraction of the asymmetrical part of the light beam is also similar. The symmetrical part of the beam from the left side of the vertical “zero line” (opposite lane) runs just below the marked dashed line, i.e. the border of light and shadow. LED lights do not dazzle drivers driving from the opposite direction, but on the left a slight asymmetrical rise of the light distribution is visible.
ROAD – OTHER FOR HALOGEN AND LED
In the case of road lights, there is a different beam distribution: halogen road lights illuminate a specific point on the road in a point or oval way (they include the beam with this point), while LEDs provide lighting for a much larger area of the road. What’s more, at a speed of 50 to 80 km / h (depending on the manufacturer), the border of light and shadow on the left is raised (the rise of the asymmetrical part of the light beam to 60 degrees). Thanks to this solution, not only the road lane but also the roadside lighting is significantly improved.