| dc.description.abstract | Light-emitting diodes (LEDs) are a good candidate for next-generation lighting due to their numerous advantages over the traditional lighting installations, such as small volume, longlife time, high efficiency and no mercury pollution. The potential in energy saving, safety, and environmental protection has made the development and applications of LEDs an emerging research area.
Due to the distinct characteristics of LEDs from conventional light sources, such as the source size, the radiant direction and the spectral content, LED lamps are more probable to induce glare that disturbs human’s visual sensation. This thesis aims to investigate the discomfort glare effects of white-light LEDs compared to the traditional fluorescent tubes. By utilizing the evaluation platform and the experimental procedure previously established in the research group, psychophysical experiments were performed to obtain subjective ratings of visual comfort through questionnaires and objective scores on visual fatigue from the critical flicker fusion (CFF) measurements.
Experimental results showed that changing lamp types (fluorescent lamps and LED lamps) did not affect human visual performance in the aspects considered in this study. There is a trend that subjects felt difficult to concentrate on reading and felt visual fatigue when LED lamps were used, but the data has not reached statistical significance. More subjects will be recruited to verify this issue in follow up studies.
Changing the illuminance level (1163 lux, 872 lux, or 490 lux) affected three factors in subjective ratings: recognition, visual disturbances, and lighting environmental preference. Higher illuminance yielded better subjective ratings, while brightness level 1 (1163 lux) and level 2 (872 lux) showed no statistical differences. Hence it is advantageous to increase the illuminance level and 872 lux is sufficiently high for energy saving consideration.
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