Non visual needs
Beyond visual needs, there are non-visual needs which influence human well-being and health to a great extent. This comprises aspects which can be visible – meaning detectable visually – but only contribute to the visual task and other visual needs to a limited extent.
Particularly relevant factors among others are:
the light’s spectral composition,
the light’s melanopic effectiveness,
the light’s variation according to the time of day (illuminance, spectral composition and melanopic effectiveness).
The aforementioned criteria and their effects are described in detail in chapter "Human Centric Lighting". Among other things, they influence the "inner clock" of human beings and thus provide them with an additional opportunity for orientation – in this instance, a temporal one instead of a spatial one.
At this point, it should be noted that the availability of appropriate light sources and control components are a prerequisite for fulfilling the described needs. A further condition is the scientific determination and a comprehensible expression of the needs themselves for planning purposes.
The latter has advanced significantly with the publication of the standard DIN SPEC 5031-100:2015-08  "Optical radiation physics and illuminating engineering – Part 100: Melanopic effects of ocular light on human beings - Quantities, symbols and action spectra" as well as DIN SPEC 67600:2013-04  "Biologically effective illumination – Design guidelines".
The development of modern LED luminaires and innovative light management systems including advanced sensors and suitable interfaces has moved the concept of Human Centric Lighting into the realm of the technically feasible and economically justifiable. Thus, the way is paved for Human Centric Lighting to progress to the stage of "generally acknowledged state of the art" in lighting (see also chapter "European standard 12464-1") and to also consider it in the guidelines for occupational safety in the future.