Scientific Study Demonstrates Positive Effects of Daylight LED on Visual Comfort, Melatonin, Mood, Waking Performance, and Sleep

It is well established that light is one of the strongest control factors for human circadian rhythms, such as the secretion of the sleep promoting hormone melatonin. Thus, optimal lighting condition during daytime are crucial to prevent circadian rhythm disturbances which can lead to sleep disorders and other life-style related diseases. Over the past ten years, there have been related scientific studies in the fields of sleep, chronobiology, physiology, as well as the impact of light quality in elderly care.

According to Prof. Cajochen's research, LED light sources with the same measured correlated color temperature (CCT) and intensity, but different spectral output, can have different effects on human behavior and physiology. LED light sources with a spectrum close to natural sunlight produced better visual comfort, more alertness, and happier moods in the morning and evening among the test participants, compared to those exposed to conventional spectrum LEDs. The research tested subjects' visual comfort, circadian physiology, daytime alertness, mood, cognitive performance, and sleep after being exposed to both conventional LED light, and natural spectrum LED light for 49 hours in a laboratory setting.

Quoting from the paper: "We have evidence that a daylight [natural spectrum] LED solution has beneficial effects on visual comfort, daytime alertness, mood, and sleep intensity in healthy volunteers. Delta EEG activity (0.75–4.5Hz) was significantly higher after daylight-LED than conventional-LED exposure during the post-light exposure night." [NOTE: Delta EEG (electroencephalogram) measurements record delta waves, the brain waves associated with Stage 3 non-rapid eye movement (NREM) sleep, or "slow-wave sleep" (SWS), and aid in characterizing the depth of sleep.]

By providing the same spectrum as sunlight and in the visible light range, SunLike Series natural spectrum LEDs deliver benefits to human well-being, consistent with the mechanisms of vision that impact both image forming and non-image forming aspects of the eye, as well as the control of circadian rhythms. While the qualities of artificial light have been described primarily with color and intensity thus far, SunLike Series natural spectrum LEDs have introduced light spectrum as another important factor in determining overall light quality.

"This research conducted by the University of Basel suggests another important aspect to the evolving direction of artificial light over the past eighty years. In addition to the properties of energy efficiency and long life, we have added the factor of 'human well-being' to modern LED light sources," said Nam Ki-bum, sales executive vice-president of Seoul Semiconductor. "As the world's first mass-produced LED devices to achieve natural sunlight quality, SunLike Series LEDs are advancing lighting technology in this important area as we continue to respond to market needs from our customers' lighting applications."

The original article has been published in the Journal of Lighting and Research Technology published on March 24, 2019.

The results of a recent comprehensive sleep study conducted by scientists at the University of Basel proves according to Seoul Semiconductor that its SunLike Series natural spectrum LEDs have been identified as a key light source for promoting human well-being,

Seoul Semiconductor developed SunLike Series natural spectrum LEDs in collaboration with Toshiba Materials' TRI-R spectrum technology in 2017 as the first LED light source to closely match the spectrum of natural sunlight. The two companies have since promoted this natural sunlight spectrum technology through its favorable effects on human well-being and sleep as a key value in the evolution of lighting.