Effects of Luminous Intensity Distribution of LED Luminaires on United Glare Rating, Illuminance, and Illuminance Uniformity Values

Due to the characteristics of optical straightness in LED chip, LED flat panel luminaire should be used for a lambertian luminous intensity distribution. However, sometimes, diverse luminous intensity distribution patterns for LED flat panel luminaire are needed. In an attempt to solve this task, there has been a rising interest in the optical design of LED flat panel luminaire. For the optical design of LED flat panel luminaire, the effects of luminous intensity distribution on indoor luminous environment should be considered. In terms of the assessment indicators of indoor luminous environment, there is the UGR (Unified Glare Rating) system developed by the CIE (Commission International de l'Eclairage). In this study, UGR, illuminance and illuminance uniformity values in a room were calculated and quantitatively analyzed in order to suggest a guideline for optical design of LED flat panel luminaire by changing luminous intensity distribution through computer simulation. Various types of luminous intensity distribution for two types of LED flat panel luminaires with constant luminous flux were simulated to show its effect on UGR and Illuminance values.