Healthy, natural, efficient and tunable lighting: four-package white LEDs for optimizing the circadian effect, color quality and vision performance

Researchers in Korea have discovered that carefully designed white LEDs can help optimize an individual's circadian rhythm. Ji Hye Oh and co-workers from Kookmin University studied four-package white LEDs, which consist of phosphor-converted red, amber and green LEDs, a blue LED and a long-wavelength dichroic filter. They compared these devices with a variety of traditional forms of lighting, and found that such four-package LED designs yield a high luminous efficacy, excellent color rendering and a tunable circadian effect for regulating the secretion of melatonin. The figures of merit suggest that carefully designed white LEDs could play an important role in creating smart lighting systems that help maintain good health, bring energy savings and provide optimal visualization of colors.

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