Spectral variation of energy-efficient room lighting

Abstract

This research concentrates on advanced lighting systems with increased energy efficiency and improved color effects in relation to human-centric lighting (HCL). HCL includes the visual aspects of color perception like color temperature of light, color rendering, and, last but not least, the aesthetic image of room illumination. In addition, nonvisual effects on the circadian biorhythm, for example, influencing the melatonin hormone level, must be taken into account. Light-emitting diodes (LEDs) have the potential to meet the aforementioned demands of energy efficiency and spectral adaptation if innovative solutions (in contrast to retrofit solutions) are applied. Lighting principles and innovative luminaires are developed for typical office rooms, which allow for variable color temperatures (tunable white) and illuminances, high color rendering indices, decorative and harmonic color compositions, and circadian lighting. Various situations of room illumination are visualized. A prototype luminaire is demonstrated, and characteristics of lighting performance and energy efficiency are given.