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Oh boy, I do love reading an article in Wired about a field I specialize in. It just makes me so amazingly happy. 1.) Wired sure does love yellow light! Kinda
by sbierwagen 15y ago
Oh boy, I do love reading an article in Wired about a field I specialize in. It just makes me so amazingly happy.
1.) Wired sure does love yellow light! Kinda odd, since this is a magazine that is, ostensibly, about modern technology; unlike say, Good Old Days.[1] What they smoothly elide is that the sensitivity of the human eye peaks at 555 nanometers. (green)[2]
The more red you have in your white light spectrum, the less efficient the lamp is.
This is a hard physical limit. No amount of cleverness will get around it-- the eye just isn't as sensitive to red light. The warmer the light, the less efficient your bulb will be. 2700K (warm-white) is pretty bad. 5500K (pure white) is okay. 7000K would be ideal, but I don't think anybody actually makes lamps with a color temperature[3] that high.
2.)
...Additional colors and increased brightness required more nuanced control
of layer composition and depth. Modern LED makers accomplish this by using
precise ratios of indium, gallium, aluminum, and nitrogen for the crystal
layer, which results in a bluish color.
But on their own, not even advanced LEDs can produce anything suitable for
the living room. The blue-tinged illumination is fine for, say, a pen
flashlight on a keychain, but it doesn’t come close to the warm light the
human eye desires.
So the LEDs found in current household applications are blue diodes daubed
with a powdered coating called a phosphor, which includes rare-earth
elements that filter blue light.
Not wrong so much as massively, massively misleading. Early white LEDs were also phosphor laminated, because LEDs are monochromatic devices. There's no way to get broad-spectrum light out of them otherwise. These phosphors, by the way, are the same coatings that produce the "awful, sickly" light in the CFLs Dan hates so much. LED phosphors run off of blue light, not ultraviolet, but the principle is the same.
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1: Actual magazine, that actually exists. http://www.goodolddaysmagazine.com/ http://www.goodolddaysmagazine.com/
2: https://secure.wikimedia.org/wikipedia/en/wiki/Luminous_efficacy https://secure.wikimedia.org/wikipedia/en/wiki/Luminous_effi...
3: https://secure.wikimedia.org/wikipedia/en/wiki/Color_temperature https://secure.wikimedia.org/wikipedia/en/wiki/Color_tempera...
- ender7 15y agoHowever, their pseudo-scientific mumbo-jumbo about "what the eye desires" aside, Wired is right that people hate non-yellow light. Hate. This is a hard psychological limit. No amount of energy efficiency will get around it. If you make LED lighting, it must reproduce the color profile that people are used to from incandescent bulbs.
- calloc 15y agoI think that this is too broad of a generalisation. I personally, and many of my friends as well much prefer whiter light. When I go to the store I buy the bright white CFL's [1] that make the dark go away ... ;-) I know of many other people, including most of my family that prefer that type of light over the yellow light that incandescence provide. I grew up on CFL's though, my grandpa used to work at Phillips and used to get massive discounts on all of their products. [1]: http://www.homedepot.com/h_d1/N-5yc1v/R-100686993/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10055 http://www.homedepot.com/h_d1/N-5yc1v/R-100686993/h_d2/Produ...
- ent 15y agoMany comments on HN have said that it's totally the opposite in Asia: people Hate yellow light and like the bluish light you get from cfl:s. So I guess you really can't make statements that broad.
- ugh 15y agoWhy are you talking about efficiency? I don't understand. The preference for warm light has nothing to do with efficiency and everything to do with what people like. Its like you saying "but we can produce this green fabric much more cheaply, why do people like those damn red t-shirts so much?" One is not related to the other.
- sbierwagen 15y agoIf you didn't care about power efficiency, then presumably you wouldn't use LED lighting at all. No matter how cheap a LED lamp gets, it's never going to match a piece of wire in a glass bulb.
- ugh 15y agoThere is a middle you conveniently excluded. It's possible to care about efficiency but not quite so much as to want green light. As far as I know it is possible to make LED lights with red light which are more efficient than light bulbs. And besides: In my country I will soon be unable to buy wires in glass bulbs. I and everyone else needs an alternative.
- MaysonL 15y agoCheck out this article The Incandescent Bulbs that Comply with the 'Bulb Ban' http://www.thedailygreen.com/environmental-news/blogs/republican/incandescent-light-bulb-ban-0711 http://www.thedailygreen.com/environmental-news/blogs/republ...