本文研究夜間照明用的LED光源，以滿足人「視覺上需求」-高演色性和「非視覺效應(non-visual effect)」-低晝夜節律刺激。 在第1部分，我們研究設計LED光源並與現有市面上螢光燈特性比較。實驗的結果，由藍光LED峰波長 {Wp = 450nm}和紅色LED {Wp = 630nm}搭配的綠色螢光粉{Wp = 540nm}，可以得到色溫不同的白光光源(2300 K-5000 K)。而製成的白光LED光源具高演色性，並比螢光燈具有低的晝夜刺激值的優點。這是因為白光LED光源可選擇較短藍光LED峰波長幅射，因此可「降低作用於人眼的作用光谱 (action spectrum) 」。另外，由於光源特性，LED的「“藍光光譜能量（波長<500 nm）佔全部能量的比值”」比螢光燈低，也有效降低光源的晝夜刺激值。 第二部分探討本文設計的LED光源和螢光燈對人褪黑激素的影響。我們分析人在不同光源照射前後，褪黑激素的分泌情形。在微弱光(<10lux)的情況，有56%的增加。在LED(色溫3000 K)的情況，有42%的增加。在螢光燈(色溫3000 K，5000K)的情況下，僅為25%，15%。本文試者對光源的特性進行定量研究，我們可以發現人眼在相同視覺亮度-「流明」，褪黑素分泌的抑製作用隨生理亮度-「晝夜刺激照度」增加。而本實驗設計的LED光源為何能取得了較好的結果，是因為具較低的「晝夜刺激照度」，因此減弱於褪黑激素分泌的抑制作用。並且這些研究數據說明LED的光譜特性可以被微調，以減弱對人類的非視覺效應。 ;This paper studies the LED light source used for night lighting to meet people′s "visual needs" -- high color rendering index and “non-visual effects " - low circadian simulate values. In the first part, we design the LED light source and compare it with the existing fluorescent lamp. By adjusting the intensity of LED light source at different wavelengths, the blue light LED {Wp = 450nm} light source and the red LED {Wp = 630nm} light source mixed with green phosphor source {Wp = 540-545nm}, and white light with different color temperatures (2300 K-5000 K) can be obtained. The LED white light source has the characteristics of high color rendering index and has the advantage of lower circadian stimulation than the fluorescent lamp. This is because the LED source can choose a shorter blue LED peak wavelength radiation, thus "reducing the action spectrum effect acting on the human eye". In addition, because of the characteristics of the light source, the blue light spectral energy (<500 nm) of LED accounts for the total energy ratio, which is lower than that of the fluorescent lamp, and also effectively reduces the circadian simulate value. The second part discusses the effects of LED lamp and fluorescent lamp on human melatonin. We analyzed the secretion of melatonin before and after exposure to different light sources. In the case of dim light (<10lux), there is an increase of 56%. In the case of LED (color temperature 3000 K), there is an increase of 46%. In the case of the fluorescent lamp (color temperature 3000 K, 5000K), it is only 25%, 15%. In this paper, we quantitatively studied the characteristics of light source. We can see that the inhibitory effect on melatonin secretion in the same {visual intensity} - "lumens", the inhibitory effect increased with {physiological brightness} - “circadian flux". And why the LED light source in this experiment can achieve good results. We concluded that LED 3000 K is lower in "circadian flux" and therefore weakened in the inhibition of melatonin secretion. And these data show that the spectral properties of LED can be finely tuned to reduce the non-visual effects on human beings.
