One lens to wash it all

July 3, 2018

“Washing” a wall with light is kind of an art and is often used for atmospheric illumination and stunning effects. Now, it’s becoming easier with the help of Auer’s tailored lens design.

First: what does “wall washing” mean? On many occasions lighting designers or interior specialists like to  illuminate walls with a uniform light distribution, sometimes in lateral and height, sometimes only in one dimension. Since local conditions often offer limited space lighting fixtures have to be mounted in close vicinity to the wall. This results in extreme angular requirements. As an example, if a fixture is placed on the ceiling, at a distance of 0.5 m to a wall of 3 m height, it has to be tilted down. Doing so with a typical spot light would however result in an non-symmetrically illuminated surface of the wall. More efforts have to be put into the optical design. This allows for illuminated areas on the wall that show nice brightness homogeneity.

An optical solution to illuminate a 3 m high wall from a distance of 90 cm was the development target. A usual spot looks like this:

  Conventional spot illuminating a wall

We used our own, GPU-driven optimization algorithms to derive a better solution for this task. The result is a lens of 20 · 20 mm2 size that is placed in front of a small LED with 1.5 mm die size. The non-rotationally symmetric light distribution is achieved with a freeform lens. The faceted front structure enables both a highly controlled light emission and also a smoothing of the resulting illuminance distribution.
The stackable design allows for the mounting of arrays of optics to obtain the overall brightness level as desired. As a result, a beautiful and homogenous light intensity distribution with an overall efficiency of about 70 % is obtained.

  Homogenous light intensity distribution on the wall

Of course also non-square light distributions with non-homogenous illuminance can be tailored according to your requirements.