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Is it a suspect/dangerous laser, how can I be sure

Petrovski

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Re: Is it a suspect/dangerous laser, how can I be

I didn't say longer wavelengths are harmful, I said radiation with longer wavelengths is less harmful then radiation with a shorter wavelength when operated at the same power.  :)

Would you rather stand next to a 10kW radio transmitter or a 10kW x-ray tube?
 

Switch

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Re: Is it a suspect/dangerous laser, how can I be

I said radiation with longer wavelengths is less harmless then radiation with a shorter wavelength when operated at the same power.
Your statement

It's a lie.

The longer the wavelength, the less harmful radiation becomes btw.
:D
 

jimmycr

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Re: Is it a suspect/dangerous laser, how can I be

hmmmm all a bit confusing :-/

What is more harmfull 50mW of green in the eye or 50mW of IR assuming everything else is equal?
 

Razako

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Re: Is it a suspect/dangerous laser, how can I be

jimmycr said:
hmmmm all a bit confusing :-/

What is more harmfull 50mW of green in the eye or 50mW of IR assuming everything else is equal?
50mw of green. The inside of your eye is reddish in color so green will burn it more easily. Also your eye will focus green down to a smaller spec on your retina and shorter wavelength photons carry more energy.
 

Petrovski

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Re: Is it a suspect/dangerous laser, how can I be

Switch said:
I said radiation with longer wavelengths is less harmless then radiation with a shorter wavelength when operated at the same power.
Your statement

It's a lie.

The longer the wavelength, the less harmful radiation becomes btw.
:D
Correct, I didn't mention that the power variable should be kept constant when comparing wavelengths at first. You could also argue I failed to specify other constants like the exact range to the radiation source, the anode material of the x-ray tube, the medium of the test environment, and so on. All relevant if you would like to accurately measure radiation effects on a human. But my reply wasn't intended to be a science thesis, I'm sure people get the picture. ;)
 

Switch

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Re: Is it a suspect/dangerous laser, how can I be

jimmycr said:
hmmmm all a bit confusing  :-/

What is more harmfull 50mW of green in the eye or 50mW of IR assuming everything else is equal?
But everything else is never equal. :p
Actually, Petrovski, I was just pointing out that you used 2 opposite terms in the same context.First you said "less harmful", then you said "I said 'less harmless' " which you didn't, cause you said "less harmful", so it's a lie(or a mistake, but I wanted to use the "the cake is a lie" phrase :D) :p
 

Ace82

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Re: Is it a suspect/dangerous laser, how can I be

Wow. Look what this thread has become. This topic has been discussed several times on LPF, and I think it will always continue to reoccur. Anyway, our eyes absorb ir although we can't see it, and if it's collimated enough could be very harmful because your eye doesn't have any reflex defense aka blink, squint, or even look away. Have you ever saw yourself on an ir camera where it looks like a light is blasting in your face although all your eyes can see is the faint red of the leds? It is dangerous because we have natural reflexes to defend our eyes from light we can see, and we relax, or even open up to more danger when we can't see it. The concept of something harmful that's invisible is frightening and makes people overly concerned about it. To destroy a laser because of this is simply nonsense, erratic, and ignorant.

Uv on the opposite side of the spectrum is still dangerous, still invisible, but our eyes reflect most of it thus significantly reducing the danger vs. ir.

To stay safe from ir, just use common sense and try to keep yours and others eyes away from the beam and watch out/avoid reflective surfaces. Mainly, don’t be messing with ir diodes by them selves without eye protection because your eye will invite the invisible light in to be absorbed by your retina.
 

Razako

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Re: Is it a suspect/dangerous laser, how can I be

Ace82 said:
Wow. Look what this thread has become. This topic has been discussed several times on LPF, and I think it will always continue to reoccur. Anyway, our eyes absorb ir although we can't see it, and if it's collimated enough could be very harmful because your eye doesn't have any reflex defense aka blink, squint, or even look away. Have you ever saw yourself on an ir camera where it looks like a light is blasting in your face although all your eyes can see is the faint red of the leds? It is dangerous because we have natural reflexes to defend our eyes from light we can see, and we relax, or even open up to more danger when we can't see it. The concept of something harmful that's invisible is frightening and makes people overly concerned about it. To destroy a laser because of this is simply nonsense, erratic, and ignorant.

Uv on the opposite side of the spectrum is still dangerous, still invisible, but our eyes reflect most of it thus significantly reducing the danger vs. ir.

To stay safe from ir, just use common sense and try to keep yours and others eyes away from the beam and watch out/avoid reflective surfaces. Mainly, don’t be messing with ir diodes by them selves without eye protection because your eye will invite the invisible light in to be absorbed by your retina.
Actually UV is absorbed by the outer parts of the eye and causes cataracts. Short wavelength uv is incredibly bad for your eyes.
 

Petrovski

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Re: Is it a suspect/dangerous laser, how can I be

Oh crap... totally missed that typo. :eek:

So much for my lengthy reply. ;D
 

Ace82

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Re: Is it a suspect/dangerous laser, how can I be

Razako said:
Actually UV is absorbed by the outer parts of the eye and causes cataracts.  Short wavelength uv is incredibly bad for your eyes.
Oh yeah, thanks for refreshing my memory. I stand corrected. This is the very reason I wear sunglasses every day. However, I was taught that uv is way less dangerous then ir for your vision, I just couldn't remember exactly what the case.
 

Petrovski

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Re: Is it a suspect/dangerous laser, how can I be

Yep.



After reading some Dutch sites about eyes and UV protection, it looks like Razako is right. UV is absorbed by your cornea and lens. A short-time overdose will cause complaints like snow blindness, but the eyes will recover in a few days. Prolonged exposure to high doses of UV light (for people who live near the equator for instance) will cause a more rapid 'aging' of the eyes, causing the lens to blur.
 

L4sers

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Re: Is it a suspect/dangerous laser, how can I be

Damn 200mW... im gettin a 10mW - 30mW... I'd watch out if you're inside.
 

Ace82

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Re: Is it a suspect/dangerous laser, how can I be

L4sers said:
Damn 200mW... im gettin a 10mW - 30mW... I'd watch out if you're inside.
Safety goggles for anything over 5mW is highly recommended. :cool:


Petrovski, now since we've learned the affects of uv on the eye, what about ir? :-?

Just a matter of time till this thread gets moved to the 'Safety' forum. :p
 

Switch

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Re: Is it a suspect/dangerous laser, how can I be

Safety goggles for anything over 5mW is highly recommended.
Meh, there's just no point in using goggles with anything below 50mW.Maybe if you pop balloons.But since you're not burning at that power, the only thing you're looking for is visibility.And if you use goggles.... :-/ Mind as well keep the finger off the button. :-/
 

Book

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Re: Is it a suspect/dangerous laser, how can I be

Damn posts are flooding in so quickly over the hours, you talk so much!

Would you rather stand next to a 10kW radio transmitter or a 10kW x-ray tube?
X-rays are ionising, and that's another matter, we're not talking about ionising radiation here (that means, pretty much, no shorter wavelengths than violet). And I didn't say than shorter wavelengths are healthy, I just said that it doesn't necessarily follow that pattern, shorter wavelength=more harmful. Would you rather stand next to an operating 10kW microwave or some 10kW of visible light? For one, in the microwave, all the water in your body would vaporise rapidly, so you'd be quite dead.
 




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