Sunlight has made an essential contribution to the development of life since the creation of the earth, through the evolution of all living beings and into our society today. It influences the entire dynamics of the earth. The sun not only provides light for all living creatures to see, but also serves as a fundamental source of energy that makes life and growth possible in the first place.
With the possibility of generating artificial, electric light, the living space of humans has increasingly shifted to buildings. According to one study, a European spends on average 90% of the day indoors. Since the use of artificial lighting, however, people have been confronted with light that no longer corresponds to natural lighting conditions. The filament lamp was the first large-scale industrial light source to be introduced. Today we use light sources such as fluorescent tubes, energy-saving lamps and increasingly LED lamps. This has made artificial light as energy-efficient and durable as possible. However, the effect on humans was not considered. After all, people are used to the rhythm of day and night. For example, an unnaturally high amount of artificial light at any time of day or night can cause sleep disturbances, as it has properties that differ significantly from those of sunlight. In the long run, this in turn can lead to diabetes, gastrointestinal and cardiovascular problems and other health problems.