More than you ever wanted to know about LED lightbulbs

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I am a parent of a little one with ASD+ADHD. He's currently young and nonverbal, but he does tend to hide under a blanket when light is very intense or is otherwise overwhelmed, and I'm looking into lighting options to help him out as soon as I can get some concrete feedback on this. I already banned CFLs from the house and have only incandescent and LEDs (and some old-style fluorescents for track-lighting under kitchen cabinets that I usually keep off).

So I myself am not aspie (or so I tell myself), and I barely notice flicker (as a computer geek from forever I have trained myself to try to see it and I can detect 60Hz if I really try and put my eyes right next to the source though)

So far this is what I've found on the lightbulb issue:

Bottom line: Use LED if you can, but do ask to test it at the store to see if you see any undesirable effects, then keep with that same brand/model or its closest model replacements.

Now for the nitty gritty details:

- CFLs are just bad for most people who can detect 50-60Hz flickering. If old CRT TVs made you crazy, you have this problem. A compact fluorescent is the same thing as a regular fluorescent except in compact form. They're also not that great for the environment in the first place - they contain mercury and are poisonous if broken so they must be handled with care.

- LED lighbulbs are lighbulbs made out of Light Emitting Diodes. A diode is a little electronic component that only accepts electricity one way. By making tiny little holes in the diode, they cause a phenomenon called "electroluminescence" (electrons are released in the form of photon, which you can see). There is no flicker, and there is no buzzing other than the usual electronic buzzing of the power supply, which being small because it doesn't need a lot of energy, should be very manageable even for the very sensitive). Because of this "accepting electricity only one way" and the fact that the diode itself only takes direct current, LEDs use something called a rectifier. A side effect of this rectifier is that it multiplies the frequency of the output waves, so a 50-60Hz household electric current will be at least 100-120Hz, and will always grow in multiples of the base input (50Hz will be 100,150,etc and 60Hz will be 120,180,etc). This does mean higher electromagnetic emmisions so you probably want these in the ceiling and not as a desk lamp, for example (then again, we spend hours in front of our computers, so who knows..).

The white on an LED is achieved by either filtering, like on a CFL (subject to the same "tinting" issues) or by using "pixel white", in which three LEDs with right/blue/green as their base light frequency get put in the same element and they are all turned on (the way white is made on a computer bitmap).

The white is a much more noticeably white than yellow, at least on the Phillips brand I am using (for example, only some of them are replaced in the kitchen out of a set of 6 floodlights, and you can clearly see which ones from the color difference from the reflection on the kitchen counter). Apparently the Phillips crowd says their LEDs don't lose the tinting with time (I didn't know that was an issue but it would certainly explain a lot of the mixed experiences with tinting here). I'm not sure if this is a Phillips thing or a technology thing, but I can only assume that pixel-white won't lose color.

OLEDs are "organic". That is, what you are stimulating to create light is organic molecules, of the same type that chemical fluorescent agents, like the ones they use in some medical diagnosis to detect necrosis (dead cells). These have one layer of the chemical that is fluorescent and one layer of a conductive polymer to act as a wire of sorts for the electricity. Stimulate the bottom layer and the top layer glows. I am not clear on what output frequency these would run on, although since what you are looking at is a chemical compound fluoresce it's possible that there would not be a noticeable oscillation as organic compounds tend to be slow (I could be wrong on this though). This is still pretty new, as the first claimed OLED lamp was introduced in April 2008.

Something to keep in mind is that LED systems are usually intended for use with Direct Current, which means there may be a transformer in the lightbulb itself (see the EM emissions info for an explanation on this). So they could theoretically be dimmable if the transformer could be (very!) quickly switched down in DC output intensity, but this is harder to do (basically you need more complex electronics to sense this and do the right thing, which gets your lightbulb behaving more like a computer than a non-processing AC intensity thing) which means they don't tend to be dimmable individually (there are dimmer control units, specific for LEDs that will do it for a track though).

Note that LED is digital. Either on or off. So dimming does so by turning the bulb on and off very rapidly, which means you get the flicker possibilities back (they start doing so at 100Hz though so you may be OK, but it's still very important to try them out as the only dimmed light source first).

I had some links for further reading and sourcing this, but this system doesn't trust me so I guess you can PM me for them.

Hope this helps.

The real question is: Which type is the best to make a cyberpunk costume out of/use in a rave?

Thanks...I'm a bit green here but I too have banned the CFLs...everyone seems to have them and I hate them...my son does too...thankfully, my NT husband knows they have lots of mercury and hates them too...hehe

Are you sure you don't have AS? One of my fascinations is electrophysics or whatever you want to call it, and I love wires, current, ohms, capacitors, light switches, the screwdrivers required to fasten the light switches in place!! ! I could read this information all day.

Good info, thanks.

What frequency does a candle operate at?

sorry DavisDad...

i am aspie and can not tolerate CFLs - even the new 300 Hz types... they still flicker and humm... and the color (the RA of a light) makes me sick to a point i want to puke or faint after getting tunnelvision.

so far so good.

also LEDs make me sick... they do not flicker or buzz, but the color (the RA again) makes me sick the same way CFLs can. it hurts my eyes, gives me a headache. makes me feel very heavy in my head.

the RA's of those two light types are so bad (RA around 85... while the sun is RA 100 and halogen and incandescent light are above RA 95) that you can not perceive colors correctly. there are huge gaps in the light spectrum of these lights.

besides that, LEDs should be banned, due to the blue light hazard* they submit people to.

so neither of these types can be used for me... and probably nobody else who is sensitive to light types. e.g. like my aspie daughter... she can't tolerate them either.



*
http://en.wikipedia.org/wiki/Light-emit ... advantages

http://en.wikipedia.org/wiki/File:White_LED.png

http://en.wikipedia.org/wiki/Blue-light_hazard

http://www.mdsupport.org/library/blulight.html
http://www.mdsupport.org/library/hazard.html

I'm very sensitive to different types of lighting. CFL bulbs are a bad "double whammy", as they flicker AND have the reputation of bursting into flames. I prefer incandescent light bulbs, and especially the bluish halogen type for reading or close-up fine work. CFL bulbs give me a headache, and make me nervous and jumpy. So can old style fluorescent "office" fixtures. At age 43 and being in the business world, I can't always have it my way. However, if CFL bulbs had been in existence when I was a kid, I'd probably have acted out, and done poorly at any tasks under CFL lighting.

I have very little experience with LED to date, but I find the blue LED (as opposed to the yellowish LED) to be soothing and pleasant as backgroundnlighting. However, when direct,nthe LED light is kind of invasive to the eyes.

Charles

it will damage your eyes....

I find the LED christmas lights to be very painful, like they are burning my retinas, I haven't seen the larger bulbs, I thing its an aspie thing to see that 60hz flicker, to me its like I can feel it in my head, that humm from the electricity

Already using several LED lights, LED wall projecting clock and LED projectors. Now all i need is an LED girlfriend

The only problem i have with the LED lamps is that they are weak and cannot produce enough light. For the moment there is no substitute for a 60W lamp, except a low energy 11W lamp, but that is not LED.

bumping this light bulb thread because i have questions for those well informed about different types of lighting.

i recently had great difficulty tolerating a string of LED christmas lights (agree with friskeygirl, they hurt) .. all other xmas lights (except fluorescents, in which a string of tiny bulbs makes the flickering completely unbearable) were fine, and i like colored lighting. but the LEDs .. i swear i could see them flicker, but from what is written prior in this thread it sounds like this is impossible unless they were on a dimmer switch; they weren't, but were in the middle of several strings of lights .. could that dim them? i don't know anything about electricity and lighting.

my apartment is full of small lamps and i have replaced most of my CFLs now with full spectrum bulbs.

does anyone have a better suggestion?

question for those that cannot tolerate fluorescents or LEDs, what is the least irritating kind of lighting?

Sad part is the Government banned the older lightbulbs.

Did you know the bulbs containing Mercury are also a fire hazard?

I like those sun lamps that are made for people with seasonal affectivness disorder. They feel calming to me. What are they made of?