2017 Volume 66 Issue 9 Pages 634-638
Light emitting diodes (LEDs) possess advantages to be applied as one of the key medical devices in the field of phototherapy. In this paper, effects of blue light on inducing sleep have been examined based on the experiments for 100 test subjects. Narrow-band (<11 nm in full width of half maximum in the emission spectrum) irradiation was found to be more effective for inducing sleep. It should be noted that the intensity of light employed in this study was far less that that suppressing the secretion of melatonin and obstructing the circadian rhythm, which has recently extended widely. Since a variety of light sources in terms of wavelengths, bandwidths, and intensity are required in the medical applications or light therapy, LEDs are the ideal device and the efforts of developing new LEDs with the materials research of semiconductors are strongly demanded.
