Daylight is entirely different from conventional artificial light. Daylight continually changes its colour spectrum and intensity, keeping us awake during the day and relaxed in the evening. German researchers from Osram have recreated this cycle with lighting systems, and the result is improved moods and health, especially among older people.
A few years ago, Osram became one of the world’s first lamp manufacturers to offer an ‘activating’ lamp, called the Skywhite. The company also produces various lighting systems that adapt dynami- cally to light conditions throughout the day. Such systems are equipped with lamps that emit different light spectrums.
They mainly use light-emitting diodes (LEDs), as well as halogen and energy-saving lamps. An electronic control unit combines the output of these units in a manner that causes the system to alter the light spectrum in line with the time of day. Such solutions are especially in demand where people need to concentrate, as in schools, colleges and office buildings. They can, thus, be found in a conference room at the University of Madrid and in Osram plants in Augsburg and Eichstätt, in Germany.
The Osram systems are being tested in hospitals and hotels, and initial results have been very promising, according to Osram lighting expert Andreas Wojtysiak. Even the US National Aeronautics and Space Administration and the European Space Agency are testing the systems.
Osram has also developed a lighting system for examination and treatment rooms in doctors’ offices and hospitals. ‘Healthcare lighting’ allows patients to select a lighting colour they find pleasant, as well as an illuminated scene, like a vacation landscape, that will distract their attention from an examination.
Osram LED lamps are also used to enliven or tone down the ambience in relaxation cabins at airports, which are equipped with an upholstered bench, a table and Internet access, and can be rented while one waits for a plane.
Importance of Blue
One colour is particularly responsible for the biological effect of light on the human nervous system – blue.
Scientists have found that the colour blue stimulates a tiny cell system deep within the brain called the suprachias- matic nucleus. This system functions as the body’s clock, sending out signals that regulate our day-night rhythm. Knowledge of this process is relatively new, as the light receptors responsible for its functioning were discovered only about ten years ago. Located in the retina, the recep- tors are mounted like rods and cones and contain melanopsin, a pigment that reacts only to blue light. Rather than enabling vision, this light sensor is only responsible for biological reactions.
Since the discovery was made, scien- tists at Osram have been working on using light to activate photoreceptors in order to influence human circadian rhythms. The principle behind this idea is simple: light with a significant blue component should be used in the mornings and early afternoon to enhance awareness and performance. Then, as evening approaches, light should be dimmed and include warmer colours to ensure a smooth transition from the concentration mode to the relaxation mode. In this manner, the researchers hope to be able to prevent sleeping disorders, chronic fatigue and even depression.
Older people can benefit the most from this, as vision not only becomes more blurred with age but also more yellowed – and yellow pigments absorb the blue spectrum of light.