オリジナル投稿者： Miroslav Djuric ,
[http://www.marktechopto.com/Engineering-Services/measurement-of-leds.cfm|This article] offers a good explanation of how LEDs function. The Cliff's notes version is that "LEDs typically change in brightness and color with temperature. As the temperature rises, the output decreases and the color shifts towards the higher end of the spectrum." Some of the background as to ''why'' it increases increases in brightness: "...There are several factors that can affect the [wavelength]. One of these is temperature. As the ambient temperature rises, so to does the LED wavelength. This increase will typically be from 0.1nm/°C-0.2nm/°C depending on the type of LED used." As the temperature decreases, so does the LED wavelength, making the LED brighter.