Natural Light Adaptive Context Lighting System that Provides a Lighting Environment Tailored to the User’s Objectives

As modern people spend more time indoors, efforts continue to create a beneficial indoor lighting environment for each user's activity. A suitable lighting environment improves efficiency and concentration, but if not, it has adverse effects such as impeding learning. Recently, research has been active on lighting technology that provides CCT suitable for illuminance and the type of use. However, for an indoor environment created by incoming natural light and artificial light, it is difficult to provide and maintain CCT suitable for the user's activity type, and related research is also lacking. Therefore, in this paper, we propose a natural light adaptive context lighting system that provides a lighting environment tailored to the user's purpose even when an uneven lighting environment is created by incoming natural light. The proposed system measures the light characteristics of each indoor area created by natural and artificial light. Then, it adjusts the incoming natural light by controlling the blinds based on the illuminance of the window. Afterward, individual control of LED lighting is performed to provide a standard CCT for rendering the target lighting environment, creating a lighting environment for each objective, classified into general office work, low-intensity work, and high-intensity work. In the performance experiment, a lighting environment for each aim is created within a 5 % error range despite the influence of continuously changing natural light throughout the day.