Visible light synchronizes the human biological clock in the suprachiasmatic nuclei of the hypothalamus to the solar 24‐hour cycle. Short wavelengths, perceived as blue color, are the strongest synchronizing agent for the circadian system that keeps most biological and psychological rhythms internally synchronized. Circadian rhythm is important for optimum function of organisms and circadian sleep–wake disruptions or chronic misalignment often may lead to psychiatric and neurodegenerative illness. The beneficial effect on circadian synchronization, sleep quality, mood, and cognitive performance depends not only on the light spectral composition but also on the timing of exposure and its intensity. Exposure to blue light during the day is important to suppress melatonin secretion, the hormone that is produced by the pineal gland and plays crucial role in circadian rhythm entrainment. While the exposure to blue is important for keeping organism's wellbeing, alertness, and cognitive performance during the day, chronic exposure to low‐intensity blue light directly before bedtime, may have serious implications on sleep quality, circadian phase and cycle durations. This rises inevitably the need for solutions to improve wellbeing, alertness, and cognitive performance in today's modern society where exposure to blue light emitting devices is ever increasing.

中文翻译：

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内部时钟-蓝灯设置人的节奏。

可见光将下丘脑视交叉上核中的人类生物钟与太阳24小时周期同步。短波长，被认为是蓝色，是昼夜节律系统最强的同步剂，可以使大多数生物和心理节律保持内部同步。昼夜节律对于生物体的最佳功能很重要，昼夜节律性睡眠或苏醒或慢性错位常常可能导致精神疾病和神经退行性疾病。对昼夜节律同步，睡眠质量，情绪和认知能力的有益影响不仅取决于光谱成分，还取决于照射时间及其强度。白天暴露于蓝光对于抑制褪黑激素的分泌很重要，松果体产生的激素，在昼夜节律的夹带中起着至关重要的作用。暴露于蓝色对于保持白天的有机体健康，机敏和认知能力很重要，而就在睡觉前长期暴露于低强度蓝光下，可能会严重影响睡眠质量，昼夜节律和周期持续时间。在当今不断增加的蓝光发射设备暴露的现代社会中，不可避免地增加了对改善健康，机敏性和认知性能的解决方案的需求。可能会对睡眠质量，昼夜节律和周期持续时间产生严重影响。在当今不断增加的蓝光发射设备暴露的现代社会中，不可避免地增加了对改善健康，机敏性和认知性能的解决方案的需求。可能会对睡眠质量，昼夜节律和周期持续时间产生严重影响。在当今不断增加的蓝光发射设备暴露的现代社会中，不可避免地增加了对改善健康，机敏性和认知性能的解决方案的需求。