Does an LED emit harmful wavelengths outside of visible spectrum?

[Turbo DV8]

Other than being insanely bright when an LED is looked at directly, are there harmful invisible waves present which could damage the eye? IR? UV? I ask because every now and then I have this incredible, uncontrollable urge to quickly glance right at the LED. Admit it, you've done it too at least a few times, and you know it!

 

[FatalDeception]

yeah i do it heaps to my L0D-CE lol.. just to see how bright it is..

 

[wakibaki]

The answer is a qualified no. Most LEDs, even white ones, are comparatively narrowband devices.There are no harmful invisible waves other than from LEDs designed to produce UV. LEDs can be designed to produce IR but it is not harmful to the eyes at the levels generally encountered.

Most current white LEDs produce blue light some of which which is reradiated as yellow by a phosphor. The mixture looks white. This approach can also be used with UV LEDs exciting phosphors, but this seems to be more a prospect for the future. In any case UV levels would require to be strictly controlled in devices intended for general illumination.

Intense visible light, on the other hand, can be harmful.

The urge is not uncontrollable. If you must look into the beam, do it at long range.

I believe LEDs are to be controlled for health and safety purposes under the same legislation which controls lasers.

w

 

[cdosrun]

I find it funny that LEDs are to be controlled for H&S, yet incands that turn out far more UV and IR (in addition to vis) are not.

The newer LEDs must be getting interesting from a safety standpoint though, the P1D-CE turns out enough light that it feels hot when pointed at my skin (I know incands have been doing that for a long time, but that was with IR). It can't be particularly good for the eyes, the newer the torch, the longer it takes for the spots to go

Andrew

 

[winny]

Other than being insanely bright when an LED is looked at directly, are there harmful invisible waves present which could damage the eye? IR? UV? I ask because every now and then I have this incredible, uncontrollable urge to quickly glance right at the LED. Admit it, you've done it too at least a few times, and you know it!

IR isn't that dangerous to your eye. You can stand in front of a 10 MW fire and look at it without any problems. Also, one of the biggest problems with LEDs is that they don't emit (much of) their waste heat as IR - so no problems with emitted IR here.
White LED's emit very little light/power under 400 nm so you are safe from UV as well.

 

[Ra]

Other than being insanely bright when an LED is looked at directly, are there harmful invisible waves present which could damage the eye? IR? UV? I ask because every now and then I have this incredible, uncontrollable urge to quickly glance right at the LED. Admit it, you've done it too at least a few times, and you know it!

Nope !! waki already said it: White led's do not emit harmfull wavelengths.

And: Staring at them is not a wise thing to do, but it will NOT !! cause eyedamage! OK.. you must not stare at them for minutes.. but even then, the artifacts in your vision, caused by that, will dissapear in time..

Its all about surface brightness (I've used that word many times at CPF..) Don't compare led's with lasers !!! Lasers have ultra-high surface brightness, they can concentrate a huge amount of light-energy at a tiny spot in your eye: That is causing eyedamage! Fortunately, the optical abberations of your eye will save your eye if the laser is not too powerfull..

Ever looked directly at the sun?? Eyedamage as a cause of that?? The sun is much, much more dangerous then any white led !!!! It has over 140 times the surface brightness of the most powerfull led's !

AND:

Lasers can have a mere 5,000 times the surface brightness of the sun !!!!!!!!


Regards,

Ra.

 

[IMSabbel]

Other than being insanely bright when an LED is looked at directly, are there harmful invisible waves present which could damage the eye? IR? UV? I ask because every now and then I have this incredible, uncontrollable urge to quickly glance right at the LED. Admit it, you've done it too at least a few times, and you know it!

No,but the VISIBLE radiation is more than enough to harm the eye if you decide to plant that new p1d-ce directly on your eye.

 

[frenzee]

IR isn't that dangerous to your eye. You can stand in front of a 10 MW fire and look at it without any problems...

This is absolutely incorrect. An IR point source light such as an IR LED, if looked at directly will create a concetrated point of IR radiation in the retina and can "cook" the retinal cells - even at low power levels. Since the human eye is basically insenssitive to IR, your pupils will not contract and therefore let in the entire flux without your knowing it. Comparing this to looking at a fire is like comparing apples and oranges. A flame is very diffuse compared to an LED and it emits visible light which cause the pupils to contract and protect the eye.

 

[Jasmes]

No,but the VISIBLE radiation is more than enough to harm the eye if you decide to plant that new p1d-ce directly on your eye.

Have you never had an eye doctor examine your retnas?

 

[2xTrinity]

This is absolutely incorrect. An IR point source light such as an IR LED, if looked at directly will create a concetrated point of IR radiation in the retina and can "cook" the retinal cells - even at low power levels. Since the human eye is basically insenssitive to IR, your pupils will not contract and therefore let in the entire flux without your knowing it. Comparing this to looking at a fire is like comparing apples and oranges. A flame is very diffuse compared to an LED and it emits visible light which cause the pupils to contract and protect the eye.

How about a 250W heat lamp? I've seen lots of hotel rooms with those installed. Seems like you'd have a lot of IR surface brightness on the filament of that light, and you wouldn't necessarily have the pupil contraction reaction as those lights are fairly dim (especially if they filter out the visible light).

 

[ROVER]

Listen to RA--the fact that your p1d-ce causes a temporary chemical change in your eye which requires several minutes to recover from does not put it up in the danger levels with laser or direct sun exposure. If you're truly worried about safety--search the archives. This is all another reincarnation of an old and dead discussion


Now to the original question of the breadth of wavelengths emitted by a single led: consider the fact that people have favorite color bin codes for leds here. Some leds don't let us see the depth of colors that others do. You never see posts on the incan section about a guy who doesn't see reds showing up vividly with his new light.

Perhaps you can go to ledmuseum.org. In addition to lesting lots of lights, and getting a lot of us hooked on leds back before luxeons, Craig has been graphing how much light various LEDS put out in different parts of the color spectrum (from UV to visible to IR). It is clear that LEDs emit their light in far more narrow spectrum of the color spectrum that incans. This doesn't mean that LEDs can't be created to give any certain wavelengh-just that all their energy is sent out in a narrow wavelength. This is why a 3W red luxeon behind an red plastic automotive filter is a whole lot brighter than a 3W incan bulb behind the same filter---because even though it puts out less light in total, it's got a lot more where it counts. Laser diodes have very narrow range too, but they also have the whole lets-focus-all-the-light-into-an-insanely-concentrated-spot thing going on. They are cool and good for their intended purposes, but require extra safety considerations.