Human Centric Lighting, designed by Francesco Iannone and Serena Tellini
CIRCA-DIANA bulb represents a new-generation LED source designed according to the most advanced Human Centric Lighting (HCL) principles, i.e. to synchronise artificial lighting with human biological rhythms, improving well-being, cognitive performance and sleep quality. The integrated circadian system acts on light spectral, temporal and intensity modulation, directly influencing the human neuro-endocrine system by stimulating intrinsically photosensitive retinal ganglion cells (ipRGCs), which regulate the sleep-wake rhythm.
The control of the light cycle allows the human body to properly recognise the day/night alternation and to synchronise the key physiological rhythms.
During the day, higher intensity light enriched with cooler components promotes alertness, concentration, and cognitive performance.
In the evening, the reduction of the blue component prevents interference with the melatonin production, facilitating relaxation and sleep quality.
The source is available in two configurations: CIRCA-VARIA standard version, with a traditional tri-edge dimmable LED chip, and CIRCA-DIANA circadian version, featuring a dedicated chip for biological spectrum management.
This new-generation bulb results from the integration of circadian technology, smart control and advanced design, bringing Human Centric Lighting principles into residential and professional areas. The integrated circadian system is managed via the Smart Life app connected to the 2.4Ghz home WIFI, which allows two operating uses. Automatic “Biorhythm” mode where the light source automatically modulates luminous intensity and colour temperature throughout the day, simulating natural sunlight progression. Manual mode, where users can set customised scenes (work, relaxation, entertainment) based on operational needs or time of day. The result is a dynamic, adaptive light consistent with the human biological rhythm.
The light source is designed with a circadian-optimised spectrum, balancing visual efficiency and biological response. With a reduced blue light emission (460–490 nm) in the evening to limit melatonin inhibition, or with a continuous balanced Spectrum, with enhanced warm wavelengths (yellow, amber, red) during relaxation phases. Finally, with high colour rendering for a natural and accurate colour perception (Ra95). This approach reduces visual fatigue and preserves the proper sleep-wake cycle balance. The emitted light directly interacts with the neuro-endocrine system through the stimulation of light-sensitive retinal ganglion cells (ipRGC), influencing melatonin production (sleep), cortisol regulation (activation), sleep-wake cycle, attention, memory and cognitive performances, mood and psychophysical well-being. Thus, proper spectrum modulation throughout the day improves the indoor life quality.
Beyond its biological component, the source delivers high lighting performance, thanks to up to 800 lumens luminous flux, continuous dimming for precise intensity control, high colour rendering (Ra95), and decorative yet fully functional light, suitable even as primary illumination. Besides, the combination of visual comfort and energy efficiency makes the bulb suitable for professional use.
The formal design is authored by architects Francesco Iannone and Serena Tellini, recognised experts in human-centred lighting research. Futuristic design is not merely aesthetic, but an integral part of the lighting concept. The source geometry generates soft dynamic light patterns on the surrounding surfaces. Light thus becomes an active architectural element, engaging with space and enhancing its identity. A high-tech circadian lighting solution, designed for contemporary applications where light does not just illuminate, but becomes a tool for well-being and space quality.
The ideal application areas are undoubtedly advanced residential, hospitality and wellness, human-oriented workspaces and, of course, high-end architectural projects.
So here is a new-concept light bulb that combines science, technology and design, engineered to interact with the human body and architecture. No longer static light, but biologically synchronised illumination, enhancing comfort, performance and space perception.
Daylight Italia is present at Light + Building 2026 (Hall 4.1 Booth A28) to present CIRCA-Diana and all other innovations, to share the future of well-being-oriented lighting
