The right lighting, around the clock

5 min.

In human-centric lighting, the focus is on the impact of lighting on health and performance. Plastics that can act as light guides, such as acrylic glass from the PLEXIGLAS® brand, enable the precise creation of dynamic light scenarios throughout the course of a day.

© Röhm GmbH

What effect does artificial light have on our circadian rhythm? How does it impact our performance? The effect of artificial lighting on our physical and emotional wellbeing is becoming ever more important. In this regard, experts use the terms human-centric lighting, integrative lighting or biodynamic lighting – a market that analysts believe harbors average annual growth potential of over 25 percent up to 2027. Developers of contemporary lighting concepts and luminaires should therefore prepare for an increasing awareness of the biological impact of light amongst consumers.

LED technology: benefits beyond energy efficiency

When it comes to human-centric lighting, digital LED technologies are seen as the key to success, just as they changed the game in the lighting sector over the past few years when it came to increasing energy efficiency. “But LED luminaires always rely on light-scattering and light-guiding materials,” says Matthias Schäfer, a lighting expert in the Acrylic Products business unit at Röhm GmbH.

LEDs create points of light that then have to be distributed homogeneously, an effect that can be achieved using light covers made from PLEXIGLAS®, the brand acrylic glass from Röhm. With intelligent control, LEDs provide the opportunity to better reconcile artificial and natural light with the natural circadian rhythm.

PLEXIGLAS® acrylic glass for luminaires

The diverse PLEXIGLAS® brand portfolio comprises a material that has been proven over decades in luminaire design, in light planning and for light solutions.

Discover more about the diverse application options of PLEXIGLAS® acrylic glass for luminaires or order a sample from the section of our online shop on designing luminaires with PLEXIGLAS® acrylic glass.

© Röhm GmbH / Source: Lighting Europe

Light throughout the day

“Current research proves that light has a significant impact on the circadian rhythm and therefore on the circulatory system, hormone levels and metabolism,” says Prof. Soyhan Bagci, who is researching the impact of light on human health at the University Hospital Bonn. If we spend most of our time indoors, our body’s circadian rhythm – which was originally regulated by sunlight – becomes imbalanced.

The problem: indoor society

“If we give our bodies the right light, we strengthen our immune systems,” explains Prof. Bagci. “However, we have shifted towards an indoor lifestyle as a society and are therefore subjected to artificial light even during the day.” It is estimated that many people spend 90 percent of their time indoors, such as at school or in the office.

© Röhm GmbH

The problem: incorrect lighting

A lack of daylight is not the only factor that can impair health and performance: The same applies to artificial light if it does not fulfill the needs of our bodies. As such, Prof. Bagci believes it is important to take knowledge on the impact of light on our health into consideration when designing contemporary lighting systems.

© Röhm GmbH

Driven by the increasing demand in the human-centric lighting segment, manufacturers of luminaires are currently developing ever more lighting systems that take the interplay of natural and artificial light into consideration – like the biodynamic luminaires from MELALUX lighting.

In close collaboration with various partners, the company has developed biodynamic lighting solutions for private users, as well as offices and hospitals. “Our goal was to build high-quality luminaires that emit light in a spectrum that is conducive to our biological cycles,” says one of those involved, Rolf Göbel from Alanod GmbH & Co. KG.

A partner for healthy light

All MELALUX luminaires are designed and manufactured in Germany.

Manufacturer: MELALUX; design: OCARI; aluminum mirror: Alanod GmbH & Co. KG

This is achieved by using a computer chip that controls the LED lighting depending on the time of day and the ambient light. “When designing biodynamic lighting, it is important to realize that the lighting situation changes throughout the course of the day and does not simply switch between cold and warm shades of white – all while ensuring that a pleasant, glare-free illumination is generated,” explains Göbel. The LEDs are therefore not visible as light sources; instead, the light is emitted from engraved patterns in a light guide made from PLEXIGLAS® acrylic glass and is then reflected from an aluminum surface, depending on the luminaire.

Precise replication of lighting scenarios

Its absolute colorlessness and ability to conduct light means the brand acrylic glass from PLEXIGLAS® is able to replicate illuminance and color temperature without any optical losses or color changes. “This makes it possible to create the fine and gradual shift between the lighting scenarios,” Göbel explains. “Since you do not look directly into the LED light sources, the light is also very pleasant and glare-free, even when working on a screen.”

Daylight window

A light panel with the same effect as a traditional window: The MELALUX daylight window automatically adapts the lighting depending on the time of day. During the day, it has a stimulating and vitalizing effect, while in the evening, it aids the body in preparing for sleep. The precise light graphics in the light guide made of PLEXIGLAS®, the brand acrylic glass from Röhm, and the high-quality aluminum mirror from Alanod GmbH & Co. KG lend the product a high-quality appearance, even when turned off.

Flexible design

The light graphics can be customized and are engraved in the light guides made from PLEXIGLAS® acrylic glass. Light is emitted from these engravings and, in the case of the “Cascado” ceiling lamp, amplified with a reflector. This technology creates ever greater luminance and ensures excellent lighting.


The MELALUX luminaires are also available without an aluminum frame. Laser engravings in the light guides made from PLEXIGLAS® acrylic glass make it possible to select custom designs and shapes.

The future of human-centric lighting

Such biodynamic lighting solutions could become the industry standard in the future – at least if Prof. Soyhan Bagci, a doctor who is researching the impact of light on human health at the University Hospital Bonn, has any say in the matter. According to him, a disrupted day-night rhythm not only impairs sleep and reduces performance, but can also provide favorable conditions for illnesses such as cancer, cardiovascular diseases, depression and even childhood obesity. “But the good news is that we can control a lot ourselves,” says the physician. “If we give our bodies the right light, we strengthen our immune systems.”

“If we give our bodies the right light, we strengthen our immune systems.”

Prof. Dr. Soyhan Bagci, University Hospital Bonn

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