Development of a natural light reproduction system for maintaining the circadian rhythm

Abstract

Circadian rhythm is linked to sleep, arousal and human health overall, affecting body temperature and heart rate. A 24-h natural-light cycle provides optimum lighting environment for humans. However, as people increasingly stay indoors with artificial lighting, lacking periodic characteristics, imbalance in the circadian rhythm ensues. Previous lighting-related studies to resolve such problem partially provided the colour temperatures of natural light but failed to reproduce the 24-h periodic characteristics of it. This study proposes a natural light-reproducing system that provides the daylight cycle characteristics of natural light in order to maintain the circadian rhythm. Natural light was measured through an optical measurement equipment, while the characteristics (colour temperature and short-wavelength ratio) of natural light by season and time were analysed. Subsequently, the control indicator of seasonal and hourly lighting was extracted and applied to the light-emitting diode lighting to provide lighting service, executing a daylight cycle that reflects the characteristics of natural light. After the sunset, especially, the circadian rhythm was maintained by minimizing the short-wavelength ratio of the lighting while maintaining indoor illumination.

Microwave‐Driven Construction of MoS2/Graphene Heterostructure for Enhanced Photodegradation under Natural Light

“…(c‐ no filter) Since natural light includes all possible vibration directions perpendicular to the light propagation direction, no filter was added. [ 31 ]…”

Design of Indoor Lighting Control System for Human Body Signal Acquisition Based on Internet of Things

“…Jain and Garg examined the presentation and attainability of different sunlight determining techniques and their application in controlling blinds and incorporated lighting frameworks [6]. Kim et al proposed a characteristic light multiplication framework that gives the sunshine cycle attributes of regular light to keep up with circadian rhythms [7]. Singh et al have studied developing a complete proof system that requires the development and integration of various technologies that can be used to develop smart homes [8].…”

Method of Calculating Short-Wavelength-Ratio-Based Color Temperature Supporting the Measurement of Real-Time Natural Light Characteristics through RGB Sensor

“…At this point, each wavelength was classified into the following wavelength bands: 380–480 nm for short-wavelength, 480–560 nm for middle wavelength, and 560–780 nm for long wavelength. The band-by-band ratio of each wavelength was calculated using Equation (1) [ 13 ]. …”

“…A precedent study showed that the characteristics of a spectrum or the color temperature of natural light contributes to maintaining human body circadian rhythms [ 8 , 9 ] and showed that the characteristics of a certain short-wavelength band (460 or 446–488 nm) are related to sleeping and wake-up cycles [ 10 , 11 , 12 ]. Kim et al analyzed the characteristics of natural light collected through an experimental test and suggested a standard for controlling the circadian color temperature of natural light to support the circadian rhythm [ 13 ]. Moreover, in the lighting field, LED light sources and lighting products for realizing the spectral characteristics of natural light have been developed [ 14 ].…”

“…As such, studies are actively being conducted on lighting technology for realizing the characteristics of natural light, and the importance of accurate measuring and analyzing technologies for natural light is being emphasized [ 18 ]. Particularly, in the field of healthy lighting that supports circadian rhythms, the color temperature and short-wavelength property information of natural light, which change every moment, are very important [ 13 ]. In general, natural light is measured using specialized optical measuring equipment such as a spectroradiometer, through which the characteristics of the SPD (spectral power distribution), chromaticity coordinates, and color temperature can be gathered [ 19 ].…”