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LED is the most recommended light source nowadays. Apart from light bulbs, it is also used in the background light of electronic display screens, such as your smartphone 1   and computer monitors/screens 1 , etc. As LED is not too hot and energy saving, it is greatly promoted and is used to replace other more traditional light sources, such as fluorescent tubes, curlicue compact fluorescent light bulbs, and incandescent light bulbs. However, it is exactly because LED lights produce a fair amount of light in the blue spectrum 4   (or called ‘blue light’), that they are so bright! There is no free lunch in this world; we may be paying a price 4 to use LED. According to a research paper called ‘The Effects of Blue Light On Ocular Health’   5 , written by Elaine Kitchel of the American Printing House for the Blind, the wavelength of blue light is ‘near UV’   5 :  http://www.tsbvi.edu/instructional-resources/62-family-engagement/365...

English translation 'What is LED? Its disadvantages and problems:  https://ledandbluelight.blogspot.com/2016/11/what-is-led-its-disadvantages-problems.html LED (Light emitting diode) 中文譯為發光二極管或 發光二極體 ，是現在最受推崇的光源，除照明用的燈泡， 也用於電子屏幕照明用，例如你的智能手機 1 、電腦顯示屏 / 螢幕 1 。 由於不太熱、節省電力，所以 LED被大力推崇， 要取代其他舊式發光燈源，例如光管、慳電膽、鎢絲燈等。 但正因為 LED燈比起光管或慳電膽， 有相當多藍光 4  (light in the blue spectrum 4 , or called ‘blue light’)， 才那麼強光 6  ! 世上那有免費午餐 ? 我們可能要付上代價 4 了! 根據美國視障服務機構 American Printing House for the Blind 的 Elaine Kitchel 發表的研究文章‘The Effects of Blue Light On Ocular Health’ 5 ，藍光的波長是‘近乎紫外光’(near UV)的 5  ! http://www.tsbvi.edu/instructional-resources/62-family-engagement/3654-effects-of-blue-light 另一方面，根據哈佛大學 Harvard Health Publications 發表的研究文章 'Blue light has a dark side'，慳電膽及LED燈比傳統鎢絲燈泡更節能，但也製造更多藍光 4 ，參考： http://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side 總括，不同研究或文章均指出  (見下面參考資料)，像短波長的LED這樣的新光源所引起的問題有如它聲稱想解決的問題那麼多 3 ，例...