Exploring The World Of <2% Blue Light

I researched for hours trying to get a complete picture of the origins, drivers, products, and claims around “less than 2% blue light.” As long as 6 years ago, Circadian Zirclight claimed their office products switched from conventional blue pump white LEDs during the day, to violet pump white LEDs in the evening for circadian health benefits. They were using Plessey violet pump white LEDs at that time, and ZircLight products carried the UL <2% blue light verification mark. Looking at the Plessey website today, it appears the chip-maker has shifted all of its focus to micro-LEDs for display, AR/ VR, etc.

That original focus of “<2% blue light” on human circadian products has also evolved. In the Summer of 2022, Maui County in Hawaii passed the first light pollution ordinance requiring <2% blue light sources in outdoor commercial lighting. Then in October, 2023 the nation of Chile passed the first national lighting ordinance with spectral requirements on light sources. Using Google Translate from Spanish yielded the following:

In addition to those already in force, the requirements that will apply to the Special Protection Zones are the following:

 Spectral Radiance Requirement: Currently at 15% blue light and will be brought to 1% blue light.

 Spectral Radiance Requirement for Sports Venues: For Class II and II Sports Venues according to the UNE-EN 12193 Standard, it will be 20% Blue and for Class III Venues of said Standard, it will be 15% Blue.

 Time Restriction: Illuminated Signs and Sports Venues will have the operating time limit of 00:00 hours (presumably this means off by midnight).

This July, 2023, Lumileds released its NightScape LED emitters with <2% blue light, intended for outdoor luminaires. Lumileds defines <2% blue light as emissions in the blue range of 400-500nm divided by the visible range of 400-700nm. What gets messy is that others define the percentage of blue light in different ways. Circadian ZircLight defines < 2% blue light as light in the 440-490nm range divided by the visible range, but the visible range isn’t defined in the articles I’ve found. Even assuming it is the traditional 400-700nm, ZircLight is only defining a 50nm portion of blue centered on light blue or sky blue (440-490nm), while Lumileds is using 100nm blue range between 400-500nm.

Also interesting, is the chart above showing low-blue source options for outdoor lighting. The only ones shown with <2% blue light emissions are LED phosphor-converted amber (PC amber), LED direct emission amber (DE amber), and Lumileds NightScape. We’ll keep in mind that this is sales literature from Lumileds. The intended take away is that other than PC amber and DE amber, all other outdoor light sources are greater than 2% blue content and Lumileds NightScape emitters are 1.8% blue content, with a nominal 1900K CCT.

Do you know of other LED emitters with <2% blue content, please share in the comments below. Do you know of other definitions of <2% blue content, please share in the comments below.

All images Lumileds

David Shiller

David Shiller is the Publisher of LightNOW, and President of Lighting Solution Development, a North American consulting firm providing business development services to advanced lighting manufacturers. The ALA awarded David the Pillar of the Industry Award. David has co-chaired ALA’s Engineering Committee since 2010. David established MaxLite’s OEM component sales into a multi-million dollar division. He invented GU24 lamps while leading ENERGY STAR lighting programs for the US EPA. David has been published in leading lighting publications, including LD+A, enLIGHTenment Magazine, LEDs Magazine, and more.

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