Development of UVB LED Lighting System Based on UV Dose Calculation Algorithm to Meet Individual Daily UV Dose

Abstract

Ultraviolet B (UVB) in sunlight is known to promote health when humans are exposed to optimum sunlight. Proper exposure to ultraviolet B is essential to produce vitamin D in the body, which is a particularly important factor for health. However, there has been an increase recently in the number of people who are lacking sunlight exposure due to staying indoors. Avoiding ultraviolet (UV) rays leads to health deterioration. To solve this problem, a portable ultraviolet measuring device that provides users with the UV intensity information of outdoor sunlight has been developed while UVB Light Emitting Diode (LED) lighting technologies capable of providing UVB radiation have been studied. However, existing technologies are mere methods for providing information on ultraviolet rays and artificially exposing to ultraviolet rays, and there is a risk for the UV radiation amount to not meet the daily required UV dose. Therefore, in this paper, a UVB LED general lighting system based on a UV exposure calculation algorithm that supports users’ daily required UV dose is proposed. The proposed system is composed of an IoT (Internet of Things) UV measuring device that measures the UV dose indoors, as well as outdoors, UVB LED general lighting which can safely provide UVB doses at indoors, and a smartphone which provides information on the cumulative UV dose and the estimated amount of vitamin D while it controls UVB LED general lighting. In addition, it is possible to support users’ vitamin D synthesis by providing as much UV light as its shortage through UVB LED general lighting, based on an individual’s UV exposure amount through outdoor sunlight, using a smartphone implementing a UV dose calculation algorithm. In order to confirm the performance of the proposed system, a simulation was conducted assuming that users with skin types 2 and 3 performed outdoor activities within 30 min and entered the room. The result confirmed that the proposed lighting can provide users of all ages with the UV dose required per day.

An Exploration of How Solar Radiation Affects the Seasonal Variation of Human Mortality Rates and the Seasonal Variation in Some Other Common Disorders

“…UV fluorescent lamps have, however, already been used to increase vitamin D [146,147]. More recently, UVB sources using LEDs are being developed for stimulating vitamin D 3 production [148,149].…”

Erythemal Solar Irradiance, UVER, and UV Index from Ground-Based Data in Central Spain

“…Recent publications have developed algorithms for evaluating erythemal UV doses on sloped surfaces and their application to the human body [20]. In addition, methods for daily vitamin D synthesis in outdoor and indoor conditions are being studied, with a small outdoor UVI sensor sending information to the smartphone, evaluating the user's daily dose, estimating the amount of vitamin synthesis, and gauging the UVB LED lighting required in indoor conditions [21,22].…”

Constant Optical Power Operation of an Ultraviolet LED Controlled by a Smartphone

“…Moreover, although the emission of this device was UV-A light, the same principle and instrumentation can be applied to UV-B and UV-C LEDs. Hence, a reliable UV lighting system can be constructed and some applications can be implemented, e.g., UV-B dose monitoring to meet individual daily UV-B dose [ 24 ]. This instrumentation can also be applied to GaN-based visible or white LEDs for controlling/maintaining mixed light’s chromaticity coordinates or color temperature.…”