What is the circadian rhythm ?

The circadian rhythm is a biological cycle ruling a variety of physiological processes in humans and animals. Its length is approximately 24 hours. Endogenous, it continues to operate in the absence of contact with an outside environment. It is regulated by light which has a synchronizing role.


The « Cronos » solution by Lucibel

Nowadays, people spend more than 80% of their time indoors under artificial lighting. This lack of exposure to natural light has disturbed the biological rhythm and consequently has reduced sleep by about 1 hour a day over the past 100 years. Moreover, a disturbed biological rhythm can provoke sleeping and mood disorders, a reduced concentration and stimulate seasonal depresion appearance. In collaboration with a team of neurobiologists and sleep doctors, Lucibel has designed an innovative lighting solution allowing to fill the lack of natural light exposure.



Download the Cronos Media Kit


What are the advantages ?


concentration, alertness and memory


the sleep-wake cycle


well-being and efficiency



How doest it work ?

The Cronos solution varies at all times in intensity and color temperature, by reproducing sunlight and its impact on the human body. By participating to the biological rhythm synchronization, the circadian lighting fixture provides a  natural well-being to users. Not only will the Cronos downlight reproduce the variation of the visible light (lux) along the day, but also the variation of the light which synchronizes the biological clock (m-lux). Thus, the emitted light will allow the visual function at the same time as the synchronization of the biological rhythm.
Light perceived by the eye is composed of
lux and m-lux :
Lux are captured by photoreceptors located in the retina which ensures the visual functions
M-lux regulate the hormonal balance, allowing the synchronization of the biological clock


To go a step further…

Download the document :

Leaflet Cronos 2017

Scientific collaboration
In order to develop a solution with real benefits on the biological rhythm, Lucibel has worked with a team of neuroscience researchers, experts in the circadian rhythm (chronobiologists). They studied the characteristics of sunlight throughout the day and its impact on the human body in order to offer natural light indoors. Furthermore, a close collaboration with sleep doctors allows Lucibel to test and validate the benefits of the Cronos solution.


Designed and manufactured in France

The Cronos solution, developed by Lucibel, enables the downlight to reproduce the sunlight all day long, and its impact on the human body.
This solution is entirely integrated in the lighting fixture, which means that not any external control system is required.

Thanks to an inbuilt clock, this autonomous downlight can reproduce sunlight throughout the day.
Recessed downlight with low luminance light source, the Ores Cronos reproduces the sun cycle from 8am to 6pm, when light intensity and color temperature are varying consequently. Apart from these hours, it reproduces a warm light (3000K), with a 300 lux light intensity average range, rules by an internal clock, which allows the lighting solution to be installed instead of former installations, without having to drag other electrical cables.
Download :
EDUCATION : learning, concentration
HEALTH : comfort, recovery
OFFICE : efficiency, well-being
HOTEL : recovering from jet lag


Lucibel a présenté, lors de l’évènement parisien Architect@work, ses dernières innovations, particulièrement bien reçues par les visiteurs très nombreux sur le stand.

The Cronos technology in the média (only in French)

Les Echos - Lucibel lance Cronos, le premier luminaire qui imite la lumière naturelle - 09/11/2017
«Un an après avoir révolutionné l'accès à Internet avec la lumière numérique utilisant la technologie LiFi, le pionnier français de l'éclairage LED annonce, ce jeudi, qu'il va commercialiser le premier luminaire reproduisant la lumière naturelle...»
Le - Le prix Nobel de médecine attribué à trois spécialistes de « l'horloge biologique » - 02/10/2017
«Les trois chercheurs américains Hall, Rosbash et Young ont été récompensés pour « leurs découvertes des mécanismes moléculaires qui règlent le rythme circadien. Le prix Nobel de médecine a été attribué lundi 2 octobre à trois chercheurs américains, Jeffrey C. Hall, Michael Rosbash et Michael W. Young, pour leurs travaux sur l'horloge biologique. Ils sont récompensés pour...»
Le point - Le prix Nobel de médecine revient à trois Américains pour leurs travaux sur l'horloge biologique - 02/10/2017
«Les chercheurs Jeffrey C. Hall, Michael Rosbash et Michael W. Young ont été récompensés pour «leurs découvertes des mécanismes moléculaires» qui rythment la journée. C'est l'une des récompenses les plus prestigieuses au monde. Lundi, le Nobel de médecine a été attribué à trois chercheurs américains dont les travaux sur l'horloge biologique éclairent l'adaptation du corps au cycle du jour et de la nuit...»
Inserm - Chronobiologie, les 24 heures chrono de l'organisme - 12/2013
«Dossier réalisé en collaboration avec le Dr Claude Gronfier, neurobiologiste à l'Institut Cellule Souche et Cerveau, Inserm U846, Lyon - Décembre 2013. Le fonctionnement de l'organisme est soumis à un rythme biologique, calé sur un cycle d'une journée de 24 heures. Ce rythme régule la plupart de nos fonctions biologiques et comportementales...»