The principle behind DE headlamps is similar to that of a slide projector. An elliptical reflector directs the light to a focusing lens which bundles it and projects it onto the road. A shield positioned between the reflector and the lens provides precise cutoff. DE headlamps, a Hella innovation, are ideal for low-beam and fog lamp use.
Advantages in comparison with parabolic headlamps are Smaller dimensions, Almost twice the light output, Clear cutoff, Hardly any scatter loss.