The purpose of this study is to develop a daylight device with variable optical properties using near-infrared absorbing reflectors that can provide adequate solar radiation shielding or solar heat utilization during daylight use throughout the year. By using a thermal barrier coating agent, a near-infrared absorbing reflector with high visible reflectance and low solar reflectance was created. The results of the light duct model experiment showed that daylight could be taken in stably, and solar radiation could be taken in at the solar altitude in the winter and shielded at the solar altitude in the summer.
