Artificial light or daylight clearly have important consequences for human health. Generally artificial light is being used for illumination in the dark, more rarely as ambient light or mood maker. Natural light synchronizes the external time with our circadian rhythm, better known as sleep-awake cycle.
Scientists have discovered that the light sensitive cells in the eye have a nerve connection to a tiny region in a brain called suprachiasmatic nucleus (located in hypothalamus). This region is responsible for controlling circadian rhythms. Also interesting is the fact, that suprachiasmatic nucleus has a direct nerve connection to the pineal gland (located in vertebrate brain). The pineal gland is producing hormones, which affect the modulation of sleep-wake cycle. There is no doubt that there is a direct correlation between a human health and the light.
Modern life interferes with our natural biological cycle. Excluded from the daylight we are working from morning to evening in the office. Long distant travels can lead to jetlag. Shift work can cause sleep disorder or insomnia. Depending on the climatic zone und the time of the year we do not get enough sunlight. As a result, many people are suffering from immunosuppression, lack of concentration or even depression.
The new trend in medicine and generally in healthcare is to use the light as some kind of drug: right light with a right intensity at the right time. For the selection of the light color, its spectral qualities are the determining factors. The wavelength of the visible light to human eye represents a small range between 390 nm and 790 nm.
In particular, blue, green, orange and red light have a positive effect on the interaction between the hormones serotonin, melatonin and cortisol. E.g. the blue light inhibits the production of melatonin. As a result we are more awake, can concentrate better and feel generally fitter. The physiological as well as the psychological impacts of light are important. The green light has a calming effect on the blood circulation and reduces consequently the stress. The orange light has an invigorating impact, promotes the communication and stimulates the appetite. Many other effects are well known.
Ambient illumination at home and in office are of increasing importance. Discreet gentle lighting is required while working or relaxing. Architects are committed to avoid direct light and to integrate light sources into the design and architecture of interior and exterior. The light should merge with forms and shapes. There are few lighting applications in this sector available in the market, electroluminescent systems are an example.
InovisCoat GmbH is a spin-off of the former AGFA Photo Group and has decades of experience in high-tech multilayer coating. As an expert in the production of top quality technical products InovisCoat has now made a well-known physical effect suitable for mass production of very large, light-emitting flexible surfaces. The name of the technology is Glow-Tec® and it’s based on electroluminescence (EL).
The manufacturing of lighting layers is not that easy. InovisCoat is using a high precision cascade coater to transfer continuously up to nine different functionalized layers onto a substrate. The figure 2 shows the required multilayer structure for the production of a functioning EL-system. The system is operating as a compensator, while the alternate current is activating the phosphor layer. The visual color impression can be achieved by a change in the frequency of the current. The light color depends on the respective phosphor. Blue, green, blue-green and orange colors are possible. A mixture of the different phosphors can provide a white light.
InovisCoat GmbH is collaborating with The Research Institute for Textile and Clothing (FTB) at the Niederrhein University Of Applied Science on lighting textiles for medical applications. Textiles coated with electroluminescent layers will be used in an unobtrusive manner in the therapy of people suffering on seasonal depression. Depending on the light color the lighting textiles can be used also for the care of people with dementia. Here the day structure of the patients is enforced.
At present the light therapy is actively used in the treatment of numerous physical or mental illness. Spotlight sources are typical devices for such applications. They have a disadvantage, that the person to be threated must sit quietly in the front of the light source. During this time, they can do nothing else. Not everyone has a necessary compliance, in particular people with dementia. Using lighting textiles e.g. as curtains or wall covering the therapy takes place, while the people are engaged in other activities. This requires less patience and makes the treatment more comfortable.
InovisCoat is convinced to create with Glow-Tec® absolutely new possibilities in ambient lighting with a huge impact on personal wellbeing. Homogeneous and non-blinding light is perceived as pleasant and beneficial. This is needed for discreetly ambient illumination. A further advantage of such electroluminescent systems is, that they can be deposited to various substrates as textiles, paper or films. The result is flexible and the lighting medium has a very low weight. It may be tailored and combined with any product.
In future alternative and practical lighting systems will become increasingly important. Their use will be more purpose related. Direct cold white electric light will be replaced by warmer more pleasant illuminating sources.