Author Topic: is the infrared Ligth dangerous?  (Read 9060 times)

Offline balam

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on: April 11, 2008, 12:33:13 PM
I have been reserching the IR.
some place assure that Infrared light is dangerous for the eyes.
others say not.

what do you think.

your input will be great for this forum


here are some links about this topic.

http://tldp.org/HOWTO/Infrared-HOWTO/infrared-howto-a-eye-safety.html




Offline balam

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Reply #1 on: April 17, 2008, 10:46:00 AM
any one



Offline inio

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Reply #2 on: April 17, 2008, 12:00:48 PM
Disclaimer: I'm not an Opthamoligist or any sort of expert in eye health.  I've just been using Wii Remote for a while and done a bit of research in this area since my work involves higher power sources.

Diffuse IR sources (typical IR LEDs), at the intensities we're working with it (10s to low 100s of mW) are not that dangerous unless the LEDs are so close to your eyes that mechanical risks become a concern ;).  Up closer to 1W it starts to get dangerous to your eyes when coming from a point (like the LED emitting it) and for exposure above a few seconds. 

Collimated IR sources (lasers or LEDs with collimating optics) are significantly more dangerous.  Even 5mW can be dangerous if it's concentrated to a small area and it hits someone's eye.  The problem here is that it's invisible so the eye doesn't react and protect itself.
« Last Edit: April 17, 2008, 12:03:52 PM by inio »



Offline balam

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Reply #3 on: April 17, 2008, 12:28:46 PM
wowow   thank you.
so if you close to eyes dangerouus.  how close.
what about use in schools....



Offline inio

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Reply #4 on: April 17, 2008, 12:34:47 PM
Basically there's three things that need to be considered in determining if exposure would post a risk to eye health:

1. energy density at the eye,

2. source size,

3. ambient visual light levels.

Calculating #1 precisely can be hard, but generous estimates can be made.  If I knew more about your exact usage I could help calculate this.



Offline Yozef

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Reply #5 on: April 17, 2008, 07:45:08 PM
I don't think that Nintendo would be allowed to mass produce this game system if the emissions from the sensor bar, a pretty vital part to the whole experience, was dangerous in any way.

I don't see how they would get away with it, hehe.

No doubt that, if strong enough, an IR source could be harmful to us.  Breathing has been said to give you cancer, but I'm still doing it.  =D  Haha/  :D



Offline balam

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Reply #6 on: April 17, 2008, 08:52:42 PM
tx
is good share experiences
I am wondering if the Nui table is dangerous....
so any one alse has a opinion.



Offline inio

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Reply #7 on: April 17, 2008, 10:19:52 PM
I don't think that Nintendo would be allowed to mass produce this game system if the emissions from the sensor bar, a pretty vital part to the whole experience, was dangerous in any way.

The sensor bar is, as IR sources go, extremely safe.  Instead of using a single LED, they use multiple LEDs on each end to spread out the source.  Also, it's a fairly wide angle source (about 10 degrees up and down and 60 left and right) so unless you get extremely close to it (inches away), the actual energy your eye gets is dramatically reduced.  If all the IR light the sensor bar emitted, which I'll WAG to be ~500mW, were coming from a single point, being close to that point would be dangerous.  If that light were focused into a fairly directed beam, it could be very dangerous.



Offline balam

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Reply #8 on: April 17, 2008, 10:27:31 PM
I think is great to fallow in this questions.
there are many of us that are working in this.
so safety is a must, 
the intention is not to discourage but .
to incourage better and greater products.



Offline benpaddlejones

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Reply #9 on: May 10, 2008, 08:47:30 PM
Given IR-LED's are on the end of nearly all AV remotes I doubt dangerous even if directed into the eye, otherwise a warning would be provided with the remote.

Given we can't see above I think its about 750nm, and IR-LED's are about 950nm, if we can't see it how can it damage us, its like saying a dog whistle can damage your hearing.

But certainly a question needs to be put to an opthamologist, does anyone know one???

benpaddlejones


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Offline inio

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Reply #10 on: May 12, 2008, 01:20:34 PM
The IR LEDs on remotes: 1. are fairly low power, usually drawing only about 20mA, and 2. are only on for brief periods.

The primary hazard of infrared light is localized retinal heating*. The fact that we can't see the light means our brain doesn't react to defend the eye from bright sources**.  Even thought we can't see it, the lens of the eye still focuses it down to a point, and the retina still absorbs the energy.

* As opposed to ultraviolet, where direct damage to the cells is a significant concern.

** The hazard of infrered light is thus inversely proportional to ambient visible light.  The brighter it is, the more constricted your pupils are so the less IR can get into the eye.
« Last Edit: May 12, 2008, 01:23:00 PM by inio »



Offline jafuah

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Reply #11 on: May 14, 2008, 10:34:51 PM
Like most posts have said, unless it's focused to a small area, at a relitively high power per area, and at a close distance to the eye, it really poses no risk.