Seoul's Kookmin University researchers concluded a clinical study to verify the impact of TV panels of sleep, measuring the levels of the sleep-inducing hormone melatonin in 40 adult men and women divided into groups watching the same content on either LCD or LG's WOLED TVs.

The researcher found that melatonin secretion fell 2.7% over two hours for the LCD group and it increased 8.1% in the OLED TV group. Melatonin rises in the evening to prepare the body for sleep, but the blue light emitted from displays disturbs the melatonin secretion as it confuses the body. As LCDs emit about twice as much blue light as OLEDs, it is not a surprise they have this effect on melatonin levels.