Green LED info wanted -- pure green, not yellow-green.
June 13, 2006 1:26 PM Subscribe
Tell me about the development of green LEDs.
posted by Rash to Technology (21 answers total) 1 user marked this as a favorite
The blue LED emits a lovely wavelength, and it's become so common and trendy I think of it as the color of the 21st Century. Developmental history of the blue LED is easy to come by; my favored source is
this article in an early issue of Wired
. But what about the green LED? We had green LEDs from just after the beginning, when there was only red; but those "greens" were really a yellow-green chartreuse. Actually, in addition to the familiar ruby red, there was also orange and yellow. The chartreuse was the only green available for decades, when of course there was no blue. But shortly after the blues became available, real green appeared also -- people in Silicon Valley (and everywhere, maybe) first saw it when the incandescent go traffic lights were replaced with brighter LED variants.
So how is the new, true green distinguished from the old, chartreuse kind? (I know those labeled "green" at Radio Shack are the older kind, and I imagine there's a great urge by wholesalers to unload the old, not-really-green ones.) And can you identify a source describing its development? Was real green related to blue?