Dictated by nature and therefore without risk to health is the imitation of the natural sequence of daylight over the day using artificial lighting. Darkening rooms where computer screen work is done should be avoided although.

Computer screens with good glare reduction as well as good positioning and alignment of computer screen workstations usually make this possible. In many cases, the ingress of daylight into buildings where we stay and work is however low or does not exist at all.

Coordinated artificial lighting that takes into account the changing colour temperature and intensity of daylight can provide help here to synchronise the inner clock.

The direction from which light enters our eyes and the planar characteristic of the light source are essential factors in this regard. Using the right light at the right time is always important for the application of melanoptic-effective lighting.

As a consequence, levels of wakefulness can be increased with light containing an increased blue component, but continuous lighting with such light does not lead in the long run to the desired effect. Rather, artificial lighting should contribute with a supportive role at the right time, but always permit enough relaxation phases.

Only careful, well thought-out planning can achieve an optimally positive effect of light on people without negatively affecting the user. In this sense, an artificial light source can never completely copy the characteristics of daylight but serves to provide important impulses. LED technology in particular, with its diverse control options and finely matched colour temperatures and spectra, can offer good support in use.

Requirements for light control

Integrating high-performance light control systems that are capable of implementing complex light sequences into planning is essential. A suitable control device must enable the following functions as a minimum requirement: Control of lighting with a time-based sequence with various brightness levels and light colours, in accordance with a circadian sequence plan (circadian sequence).

In some applications though, further requirements on the control device and operating interface are made. Frequently required are the following:

  • Individual adaptation of the circadian sequence by the user
  • Saving several circadian sequences for selection purposes
  • Stepless, manual setting of brightness
  • Stepless, manual setting of light colour
  • Calling preset light scenes
  • Individual adaptation of light scenes

Only in this way is it possible to implement the planning requirements of melanopic lighting.

Time of dayColourBrightness
03:102700 K55 %
04:002700 K68 %
07:002700 K100 %
10:006500 K100 %
15:006500 K100 %
18:004220 K100 %
22:002700 K68 %
23:002700 K55 %

The specific sequence is oriented to natural daylight, and is especially suitable for synchronising the inner clock of people continuously present in rooms without daylight and supporting their circadian rhythm.

Requirements for luminaires

installed as secondary light sources. Planar luminaires or indirect systems are suitable for distributing light at high levels into the upper room zone and onto the ceiling.

Such lighting systems can be supplemented with direct distribution components (with fixed colour temperature if required). In such cases it must of course be ensured that visual tasks at specific workstations are supported, and that all further visual quality criteria are met.

Specific requirements are also made on the luminaires used. In order for light to be melanopic-effective, its spectral distribution must be similar to daylight.

To simulate the daylight sequence, the light colour of the luminaire must be steplessly settable (selectable) and cover the completely required colour temperature range. Because, in addition to spectrum and intensity, the planar characteristic of a light source is essential for the melanopic effectiveness of light, luminaires should be