South Korean team develops new blue light LED that can improve human sleep

According to news on December 19, a joint team from Kookmin University in Korea and Samsung Electronics developed and designed a human factor lighting product that regulates the secretion of melatonin in the human body by combining blue light LEDs of different wavelengths to promote sleep and stay awake. The technical results have been published in the journal ACS Omega.

The research team stated that after thousands of years of evolution, humans have formed a diurnal habit of working during the day and sleeping at sunset, relying on the sun to regulate our sleep/wake cycles. But today, many people spend most of their time indoors, away from sunlight, making it difficult to maintain an optimal 24-hour circadian rhythm. Exposure to artificial light can worsen the problem of circadian irregularity, because artificial light can lead to a decrease in melatonin secretion, especially exposure to blue light at night, which can interfere with melatonin production and thus affect sleep.

Blue light is usually emitted by LED light sources in lamps, computers, TVs, mobile phones and other electronic devices that people use at night. Therefore, in order to reduce the negative impact of blue light on human body rhythm, a joint team from Kookmin University in Korea and Samsung Electronics created an LED blue light source that can simulate the natural circadian rhythm.

According to the research team, the wavelength range of blue light is 380 to 500nm. The wavelength of light that inhibits melatonin production and induces a state of wakefulness is in the range of 460 to 500nm. Therefore, the researchers designed two LEs with different wavelengths of blue light D. Among them, the wavelength of blue LED used during the day is limited to close to 475nm; the wavelength of blue LED used at night is close to 450nm, which is outside the wavelength range that interferes with sleep.

Afterwards, the researchers combined the two new LEDs to create an LED human factor lighting bulb and began a comparative test experiment. In the experiment, the new LED human factor lighting bulb was placed together with the traditional LED bulb in a windowless room, and the experimental volunteers lived in the room for three days. The researchers measured melatonin levels in the volunteers.

In the end, the saliva sample results of 22 volunteers showed that compared with volunteers who were continuously exposed to traditional LED lights, the melatonin levels of volunteers under LED human-induced lighting bulbs increased by 12.2% at night and decreased by 21.9% during the day.

The research team expressed the hope that LED lamp and display manufacturers can apply this new invention to help people increase their energy and work efficiency during the day, while improving relaxation and sleep quality at night.