Study on Discomfort Glare Rating of the Luminaire with LED Array

Abstract

The use of luminaires with LED array is increasing. The luminance distribution varies by the number and interval of the LED devices, and the diffusers used in the luminaires. Discomfort glare is a problem for practical lighting design. When using the exiting method with discomfort glare ratings, the luminance distribution is shown to be uniform. However, whether the typical luminance distribution of LED luminaires can be considered uniform is a problem. In this paper, the result of an experiment under a certain condition of the background luminance and the position and size of luminaire, is shown in which discomfort glare ratings of LED luminaires, such as offense to the eyes, glare, and the discomfort of the glare, were obtained for several luminance distributions of LED luminaires. The relationships between the transparency of the filter for visual field and the discomfort glare ratings are shown. An equivalent luminance coefficient is defined as the ratio of the uniform luminance to the average luminance of the luminaire, both which gives the same discomfort glare ratings. The equivalent luminance coefficients are shown for each luminance distribution. The UGR value, corrected by the equivalent luminance coefficient, is useful for estimating the discomfort glare rating.