Assessing glare based on LED lighting

In order to provide basic experimental data for new index to assess discomfort glare for LED lighting, subjective glare evaluation was carried out using various test stimuli having different spatial luminance distributions. Four experiments were carried out, in which the effect of luminaire homogeneity, the effect of pitch length between LED chips, the effect of chip density in a fixed area, and the effect of diffusion angle, were respectively investigated. To explain results of 4 experiments commonly, we propose “effective glare luminance” in which sum of luminance in a source area divided by the effective area (sum of the nonzero pixels). Results of discomfort glare scaling of all experiments agree well when plotted against the effective glare luminance, suggesting the validity of this quantity as a new index of discomfort glare for both uniform and non-uniform light sources.