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FrozenGate by Avery

What is the Purpose of Wearing Safety Goggles?

R

Rocketeer9697

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So I hear you must wear Safety Goggles if you have a Powerful Laser. I have a Blu Ray 400mW Laser. What kind of serious things could happen if you looked at the dot? I know that if you looked into the beam it would blind you, because that would be like looking into the sun. But why wear Laser Safety Goggles when looking at the Dot coming from the laser? Do you have to wear Safety Goggles, or Could you wear Polarized Sunglasses? :)
 





The purpose is really to avoid accidents. If there are shiny things in a room and you accidentally drop it and it reflects off of that thing in JUST the right way and hits you in the eye, there goes your vision. But, if you're wearing goggles, you will probably not take any permanent damage.

Further, for some people (not me, oddly enough), it's just uncomfortable to look at the dot without goggles on.
 
facepalm.jpg


YOU NEED GOGGLES NO EXCEPTION. Especially at 400mW!!!!!

1. the dot may reflect off of something and into your eyes.
2. The dot itself is very bright and bad for you eyes.
3. They look incredibly stylish

Okay 3 isnt a real reason, but seriously... get some goggles. You NEED them!
 
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I've been using laser for 3 years now, and I've been hit in the eye by a reflection 3 times by <20mW. The point is, ANYONE can have an accident. If they were high power I'd have blank spots in my vision.

Think of it this way. You have a laser that can blow hole through black plastic. Now think about the soft tissue in your eye.

Dont be dumb, protect your eyes.
 
Tech_Junkie is right. Being "careful" is not enough. I've only ever been hit by a laser when I was pointing it around without goggles. Luckily, like TJ, It's all been with relatively low powered lasers.

Here's some worthwhile reading
http://laserpointerforums.com/f53/hit-eye-1000mw-445nm-blue-laser-69469.html

Your laser isn't 1W, but if you get hit by a truck it doesn't matter if it's going 60mph or 80mph, you're gonna get hurt either way...
 
Point is, goggles are mainly to PREVENT accidents, much like how seatbelts are.

Sure, you can go without wearing a seltbelt and drive the car just fine...but if you were to hit something, then you'd go flying out of the car and more than likely die.

If you do wear a seatbelt, then you'd more than likely survive.

Goggles are very much a preventative measure, and I advise you get a pair of them as soon as possible, or at least, don't play with your laser without them. There's just too much to go wrong, and so much at stake. You don't want to lose your vision do you?
 
The point of goggles is to retain your vision.

Even off of what people would consider a nonreflective surface like a piece of matte finished opaque plastic you will get reflection from a laser. It is usually very diffused but depending upon the angle of incidence it can retain a very high energy density. The lens in your eye then concentrates that diffuse beam and makes it a tiny spot on your retina which has enough power to blow a hole right through it. The sun is 1mW per square millimeter. That means a 1mW laser with a 1mm^2 beam diameter has the same power. You can never predict how things will accidentally reflect in an uncontrolled space, which is why goggles are required in these conditions.

Thanks to Wolf and Jerry for pointing out the misfiring of my mathematical neurons :beer:
 
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Err, Sig, your math is off. 1cm^2 is 1/10,000th 1m^2. So if it spreads out to be 1 square meter, then its only 2.5% the power of the sun. It's definitely safe at that point, or .04mW.
 
Wolfman29 said:
Err, Sig, your math is off. 1cm^2 is 1/10,000th 1m^2. So if it spreads out to be 1 square meter, then its only 2.5% the power of the sun. It's definitely safe at that point, or .04mW.
Click to expand...

Haha yes, so it is, quite badly! Total brain fart... will edit post. XD
 
The Suns energy at an optimal sunny summer day is
about 1mW/1mm2.
I tested that on 64 square mm of thermopile sensor
surface (8mm X 8mm) on a non ideal sunny day at
1:00pm and got a reading of 56mW on that surface
area...
Had the air been clear and at 12:00 noon in the
middle of the summer it would have read higher.

If you look into the sun quickly your pupils will contract
to lets say 3mm diameter or ~7 square mm.
That is only ~7mW that enter the eyes.

I know that when I do that... I have a blind spot for
quite some time right in the middle of my field of view.


Jerry
 
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Oh, hmm. I must have copied it down incorrectly in my notes at some point. Either that or confused/mixed it up with some other constant (I'm thinking MPE limit). I have MPE limit as 1.05mW/mm^2.

My post is all kinds of fail today, my apologies. Thanks for the correction, Jerry.

Any confirmation on the MPE limit? My quick search isn't bringing it up. I'd like to correct my notes.
 
Thank you for doing that test Jerry. I was using the figure of 1020W / m2 which works out to 1.02mw/mm2. It's nice to see that this agrees with your measurement.

However, I do not agree with your 3mm diameter figure for the size of the pupils. If you stare at the sun for some reason then your eyes will contract and will indeed be that small, but if you glance at the sun or emerge from a dark room your pupils will be much larger. 6mm is a good figure, which equates to 25.5mm2.
 
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It's also question of focus. Sun, though small, is still spatial source. It cannot be focused into single point on the retina. Lasers can.
 
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