posted
It's the Christmas light time of year, which means everyone gets out their new energy efficient LED lights and strings them up around their trees and houses.
But I have a problem with this, I hate LEDs because the blue they use is far more out of focus than all the other colours. It doesn't hit the right place on my retina at all. I am told that this is due to chromatic aberration. Blue LEDs are apparently pure blue and thus have none of the other colours to make them appear in focus.
I should imagine many people have this problem, but does everyone?
Posts: 8473 | Registered: Apr 2003
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posted
Personally, I love the new LED lights. They actually look better to me and they're cheap.
The former, maybe because of the inverse of your problem since they are emitting light along a shorter range of their intended colour? *shrug*
Posts: 7593 | Registered: Sep 2006
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I can't even look at white LEDs - though I have to say that they are usually blue-white. Last year my family bought a couple of strings of them and put them up on the Christmas tree - and everyone else seemed to think they were great. But as soon as they were switched on, I couldn't even see the tree properly. The whole thing was out of focus and gave me a headache. In the end my mother took them back to the store and put the old lights back up - which was very sweet. But I dread the day when LED becomes the only kind of fairylights you can buy.
Anyway, this year there are some multicoloured LEDs strung up in the trees across the street from my house and I love them - they're incredibly bright for the size of bulb, so cheap to run that you can keep them on all month and far enough away that they'd be blurry anyway, so they don't bother me.
Posts: 1528 | Registered: Nov 2004
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How can a superbright LED be out of focus? They have no lenses, and do not project any kind of images. I have a couple of superbright LED flashlights, including one with nine LEDs in it. I still can't figure out what you folks are talking about regarding focus.
They are said to be five times as energy efficient as incandescent bulbs. Fluorescent bulbs are only four times as efficient as incandescent bulbs, require a special ballast, and both ballast and tubes do burn out eventually. LEDs should last nearly forever, since they are solid state components.
Down sides: Fluorescent bulbs contain small amounts of mercury. Superbright LED's contain gallium arsenide. The danger from the former is much greater than from the latter. It is claimed that actual tests have shown that the gallium arsenide crystals can be ingested, and pass harmless through the system, without the gallium being separated from the arsenic, so there can be no arsenic poisoning.
The main prohibitive constraint right now is cost. A superbright multi-LED bulb designed to screw into a standard light bulb socket, that would give the same light as a 35-watt incandescent bulb, would cost about $35 (according to current pricing with on-line distributors).
They are great for flashlights, especially penlights. But the price needs to come down. I am surprised, actually, that LED Christmas lights are available. Either the price has already come down substantially since last I checked, or else people are willing to pay two or three times the cost of standard incandescent Christmas lights.
If the LED Christmas lights are too bright because of the small, intense spot of light they produce, then they could be diffused by putting them inside a cheap plastic outer bulb.
Posts: 3742 | Registered: Dec 2001
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A 50 LED strand can be had for about $17 on Amazon.com
I imagine they might pay the difference in upfront cost in electrical savings over their lifetime, since they should last for years, but that might be optimistic. I think some people just like them because they are nifty.
Posts: 4287 | Registered: Mar 2005
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quote:Originally posted by scifibum: I think some people just like them because they are nifty.
Marketing specialists would call those kind of people "early adopters." They're the ones who go for any new technology that seems "nifty," as you said.
I admit I am a little that way, myself. I ordered my first superbright LED flashlight about eight years ago, and I was giving them as Christmas gifts over seven years ago.
Posts: 3742 | Registered: Dec 2001
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Being nifty has it's price. I bought one of the first LED flashlights. It was machined out of a solid block of aluminum, had 5 LED's and lasted just short of forever on 2 CC batterys. But, It has a flimsy feeling switch. It cost aprox. $50. This summer, I bought another. It has an impact resistant rubbery plastic case, 7 LED's and is still using the no name batterys that came with it. It has a much better switch. It cost $3.50. It is also much more comfortable to use, when I hold it with my mouth to free up both hands. They both have great light though.
Posts: 1167 | Registered: Oct 2005
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quote:A 50 LED strand can be had for about $17 on Amazon.com.
A local store had 200-LED, 66' lengths on sale for $12. I snapped up three, and should have bought more.
Posts: 37449 | Registered: May 1999
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Wow, they seem really popular. I don't like the colours at all. That dead grey-white, the out-of-focus blue, the emerald green. The colours are just not that pretty too me.
Posts: 8473 | Registered: Apr 2003
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posted
Incandescent bulbs are all one color as far as the filament, which is the light source. They get different colors by coloring the bulb that encloses it. So why not do the same with the superbright LEDs? Just use the white, and enclose in color bulbs. Granted, the color LEDs are intense colors. But a colored bulb enclosure would probably make the light more diffuse.
Could someone please describe the "out-of-focus blue"? I have no idea how an LED that justs glows brightly can be out of focus.
Posts: 3742 | Registered: Dec 2001
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The first time I got LED lights, I had this same experience. The issue is that the light is so bright that looking directly at it leaves an afterimage on the eye. If you move it back and forth, then, the lights will appear to "jiggle" or "flicker," and will appear fuzzy from a distance. Once they're in place and not moving, though, they're fine.
Posts: 37449 | Registered: May 1999
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