Human Centric Lighting (HCL) is a newly emerging field with its importance being studied and scientifically proving the biological effects of lighting on humans. All living beings have a biological clock, that synchronises them to the day and night cycle. This is called the Circadian Rhythm. There is different stimulus that effect and control this clock, in order to set it to the location on earth of the person.
One of the main mechanisms in the human body for setting this clock is the eye, which is tuned to the colour variation of the sun's colour and intensity, at various times of the day.
The colour changes during the day due to the refraction of different wavelengths of the sun's light as it passes at different angles through the atmosphere. This light then passes into the eye, through the ophthalmic nerve and into the brain where glands trigger hormones to either make the person more alert or induce tiredness to aid sleep, depending on the time of day.
Our lights and control systems can accurately match these light levels (lux) and colour (Correlated Colour Temperature, CCT) and natural sunlight spectrum profile throughout the day, so as not to disrupt the natural cycle. If this cycle is disrupted, not only is the person's efficiency affected but it can also lead to discomfort and eventually health issues.