The Relationship between Solid Angle, Eccentric Angle, and Luminance of Glare Source Under the BCD Condition to Understand the Effect of Visual Characteristics on Discomfort Glare

Unified glare rating (UGR), which is a general discomfort-glare index, targets design objects such as artificial lighting. Light-source size, position of gaze, etc. are limited to the specific range assumed in the process of developing UGR. Because it is necessary to reflect human visual characteristics to universally predict the rating of discomfort glare according to visual science, it is necessary to understand the ef-fects of visual characteristics on discomfort glare. In this study, which was conducted to systematically investigate visual characteristics in the visual field of discomfort glare, the effects of the solid angle and eccentric angle of the light source on the borderline between comfort and discomfort (BCD) luminance of discomfort glare were experimentally investigated. The results of the experiment revealed that the effect of light-source solid angle on BCD luminance depends on the eccentric angle. The results confirm the necessity of understanding the visual characteristics in terms of the effects of size and position of the light source on discomfort glare.