| The contents studied in this thesis were as parts of the National High Technology Research and Development Program of China (863) (No.2011AA03A113) and the National Basic Research Program of China (973) (No.2010CB734102).Due to the rapid development of the LED chips technology, the LED light sources possess the characteristics of better luminous efficiency, color rendering and energy saving compared with traditional light sources. They tend to occupy a great part of the general lighting market. Nevertheless, this kind of the point light source can produce more disturbing glare because of the smaller emitting area and higher surface luminance. Glare can impair the visual function and result in physiological and psychological discomfort, which can influence visual performance, work efficiency as well as safety. Glare is always a hot-debated topic in the lighting field. However, whether the conclusions and evaluation methods for the traditional light sources also be suitable to the LED light sources is questioned because of the different principle and characteristics, it’s necessary to deeply explore the influence mechanism of the glare from LED light sourcesAt the beginning of the thesis, the current situation of the researches on the evaluating the glare and its physiological mechanism was described, and the applicability of them to the LED light sources was analyzed. At the same time, the blank and defect of the existing researches was pointed and then the research contents and significance of this thesis was drawn forth. Afterwards, the thesis introduced the theoretical basis of the experimental design for the glare research of LED glare sources, including the basic theories of vision, the visual process and the nerve signaling pathways when experiencing glare. And then the information about the key physical parameters influencing the glare degree, the psychophysical scale quantifying the glare degree and the possible physiological reaction resulting from temporal glare were listed, which were also important clues for the variables and dependent variables selection in the experimental design. Based on these, a research approach of the influence mechanism on the psychological and physiological response was designed, which was suitable to the characteristics of LED road lights.In Chapter 3, a typical road lighting system was selected as an example,72 lighting conditions with different discomfort glare degree were set in a self-developed platform simulating the real condition. And the subjective score based on deBoer rating and the borderline between discomfort and comfort of 12 observers were recorded. Based on variance analysis, interaction analysis and regression analysis, the influence mechanism of the four variables-surface luminance, background luminance, solid and the observation angle on the psychological glare (discomfort glare) degree from LED road lights was demonstrated. The results showed that all the four variables had significant effect on discomfort glare perception with different weighting factor. A numeric model was developed and verified by extra 25 lighting conditions to prove its general validity. In addition, by comparing with the glare evaluation model developed for traditional light source, a conclusion was drawn that the psychological glare mechanism influenced by several key physical parameters has some comparability between LED and traditional light sources in road lighting.The thesis further studied the physiological influence mechanism of glare from LED in chapter 4. Four variables including the illuminance at the observer’eyes produced by the glare source, the ambient illuminance, observation angle and spectral power distribution were selected as the variables to set different glare stimulus.10 observers participated in the experiment, and the vertical electro-oculogram (EOG), the pupil size as well as the subjective rating based on deBoer rating were collected. Variance analysis confirmed the influence ways of temporal glare on the two physiological parameters at different visual conditions. A relationship between the physiological response and psychological reaction caused by LED glare was built according to correlation analysis, which demonstrated the reasons why LED glare could result in discomfort perception and visual fatigue at the point of physiological mechanism and supplied the physiological support of glare prevention.The thesis were based on the study methods in the existing researches on glare, and innovated by combining the methods of psychophysics and the monitoring the physiological response caused by temporal glare. The production and influence mechanism of LED glare were analyzed at two aspects, the correlation between the psychological and physiological response caused by temporal glare was clarified, and the difference and similarity of the glare evaluation method between LED and traditional light sources were also pointed. The conclusions can be used as guidance for lighting design against glare. |
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