The Study Of The Biological Effect Under LED Lighting

With the progress of human’s life quality,more and more people prefer an environment of healthy illumination rather than a basic achievement.Because of the advantages of illuminance,energy conservation and hue,LED is becoming used widely.As a result,the relationship between the illuminative factors and the biological effect is paid attention to.This thesis has demonstrated a set of discussions about the relationship among the illuminative factors,color temperature and biological effect,and it supports the theoretical basis of biological effect in LED illumination.Thesis can be divided into following parts:1 Introduce the background of human eyes’ visual and non-visual and its research meaning,the development process of LED healthy illumination.Systematically,this part describes the biological effect’s research status domestically and overseas.According to LED’s optical and electrical parameters,this section provides the theoretical gist to the correct application of LED in practical illumination.2 This part introduces 3 kinds of photoreceptor cells of human being,and it indicates the mechanism and characteristics of human’s visual and non-visual accesses.It surveys a scientific research report of visual and non-visual accesses globally.At the end of this part,it provides some illustrations about the factors which are influential on biological effect and how these factors influence.3 This research includes the effects of different lighting environment on human visual pathway.Firstly,using the lighting environment with different combinations including luminance and color temperature.It shows that: when the color temperature is between 2500K~3000K and illumination around 40 lx,the subjects can achieve better color vision ability.In the meantime,the dark adaptation ability has been greatly improved.Then,the experiment identify to the block with 15 different color spaces by adapting 8 different lighting conditions.The final conclusion is: under the color vision test environment,when illuminated object’s color L * brightness is in the range of 50 to 80,the subjects can distinguish colors better.And combining the dark-adapt environment to the color vision environment,the results show that: in the conditions of the white LED mixed red light,although the dark adaptation time is prolonged to some extent,the subjects can achieve the best color vision effect.4 The last part is more related to the research of effects of different color temperature(2900K,3800 K and 5000K)LED illumination environments on human non-visual pathway.The parameter variables include the heart rate before bedtime,the heart rate after waking up,diastolic blood pressure before bedtime,diastolic blood pressure after waking up,systolic blood pressure before bedtime,systolic blood pressure after waking up,and deep sleep proportion,measuring their changes while changing the illumination,to explore the effects of different illumination on human non-visual system.The results show that the impact of changes in the illumination of the heart rate as follows: with increasing color temperature,the heart rate of change will increase.The impact of changes in the illumination of the blood pressure is: when the blood pressure is under high color temperature,the value of the change increases to the maximum.The value of diastolic blood pressure will reach to 11.85 mm Hg while the value of systolic blood pressure 9.5mm Hg.In warm temperature conditions,diastolic blood pressure’s value can reach to 9.35 mm Hg,systolic blood pressure reaches 8.3mm Hg.Finally,in the white positive temperature,the value of blood pressure keeps stable compared to the previous two conditions,where the value of diastolic blood pressure is only 5.7mm Hg,systolic blood pressure only 4.2mm Hg.In addition,the proportion of the deep sleep also decreases with color temperature increasing.