Tunable LED pairing with ‘Circadian Tune’ functionality

This Circadian Tune technology harnesses NICHIA’s expertise in developing a Phosphor Converted Cyan, among other semiconductor processes and packaging techniques. The supplementary component is the inclusion of NICHIA’s newly launched LEDs with TriGain technology, a potassium fluorosilicate (PFS) based phosphor technology licensed to NICHIA through a strategic partnership with GE Current.

Most existing human-centric lighting systems mainly work by changing CCT (correlated colour temperature). Some have started using individual ‘energising’ or ‘calming’ LEDs, including NICHIA’s Vitasolis. However, NICHIA’s new Circadian Tune LED products will raise the bar to also address efficacy, colour quality and increased Melanopsin Stimulation, the light that explicitly targets melanopsin-containing neurons in the retina of the eye.

These neurons, called Intrinsically Photosensitive Retinal Ganglion Cells (ipRGCs), are connected to a region of the brain responsible for regulation of the 24-hour circadian cycle along with associated reflexive neuronal and hormonal responses to the presence of light.

Sensitive to a particular range of wavelengths, melanopsin photoreceptors reach peak light absorption at wavelengths around 490nm. By utilising NICHIA’s Phosphor Converted InGaN Cyan, NICHIA’s Circadian Tune LEDs are optimised at the most sensitive wavelength of ipRGCs. Indeed, this approach provides a higher performance through its combination of lumens per watt (lpW), TM30 and Melanopic Ratio (MR) than other human-centric lighting solutions.

NICHIA’s Phosphor Converted Cyan outperforms a pure InGaN die based cyan in many ways. As highlighted by Phosphor Engineer Sadakazu Wakui at the recently-held Phosphor Global Summit 2020, the Phosphor Converted Cyan delivers a higher lumens per watt (lpW) performance versus a traditional pure InGaN cyan.

Additionally, the PC Cyan provides the same forward voltage (VF) as standard white LEDs, as well as the same z-height for optical matching. Couple this PC Cyan and NICHIA’s Warm White LEDs with TriGain technology, the system can achieve a CRI of 90+, with high TM-30 values, while delivering a lpW performance equivalent to that of an 80 CRI LED. A balanced human circadian lighting system is achieved with simply no loss in efficacy.

Using NICHIA’s new Circadian Tune technology, the high MR and cooler CCT will reduce fatigue and provide greater alertness to help office workers remain in an awakened state of mind or help night workers complete their shifts effectively. At a low MR and warm CCT, the focus switches to relaxation, prompting a feeling of safety and initialising a transition to sleep. A sense of time is therefore introduced when both proper melanopsin stimulus and variable CCT is being applied.

“New Circadian Tune LED products are truly innovative. Through an optimisation of efficacy, colour quality and Melanopsin Stimulation, we can better target ipRGCs. Additionally, the utilisation of a traditional 80 CRI warm white for the relaxing portion limits the colour quality of the system. To overcome these limitations, NICHIA has introduced this Phosphor Converted Cyan and Warm White TriGain pairing,” explained Satoshi Okada, General Lighting Business Planning Manager of NICHIA Japan.

“NICHIA introduced Vitasolis in 2019, a range of LEDs geared to suppress fatigue and boost vitality. The Circadian Tune LED pairing builds on these innovations to offer a more dynamic and tunable solution to the global lighting industry.”

LEDs with TriGain technology are available now in NICHIA’s 757 series. The new Phosphor Converted Cyan will be available within the first half of 2021.