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Playing with a 1.5w Blue laser and my eye hurts

robomont

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basically a matt finish diffuses light in different directions.its broken up by angles in the paint surface.
if there are reflections from one in three hundred different angles.the eye is still seeing to much light.there is probly that many in a focused dot .there is no such thing as non reflective surface.if there was magicians would use it all the time.
 



grainde

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basically a matt finish diffuses light in different directions.its broken up by angles in the paint surface.
if there are reflections from one in three hundred different angles.the eye is still seeing to much light.there is probly that many in a focused dot .there is no such thing as non reflective surface.if there was magicians would use it all the time.
Jesus thanks for the info. You obviously knew I was talking about diffuse reflections as I mentioned them...:banghead: By non reflective I mean not a mirror or something shiny like glass or other reflective surface liable to give rise to a specular reflection.

Edit: Have edited "Non-reflective", which whilst theoretically incorrect, helps to describe a diffuse reflection in layman's terms.
 
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Livinloud

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my comparison is true, flashlights and lasers are of no comparison since LEDs dont have a focused beam of energy like lasers! although they have a small emitter, it is not focused at all, hence why they need reflectors to help direct the light forward. if you dropped a lens over the emitter it still wouldn't be focused because the light would bounce all over the inside of the lens.

you want a experiment to show your matte finish reflection theory is wrong? go inside and find a room that has matte walls, wait until night and turn all the lights off. now the next part is all up to you but you have two options 1) using your safety glasses shine the laser on the matte wall and take a photo of the room 2) turn around and shine the laser behind you making sure to hit the wall. now if the room is lit up blue then matte reflects light, if the room is still black then matte doesnt reflect light. i already know the answer, it will be lit up blue, hence matte reflects light! ive done this many times over the past year since my dorm had matte walls, it litterly will light the room up almost to the point where you can see everything in it perfectly
 

grainde

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Yes but the room is illuminated by the diffuse reflection, much like a flashlight also lights a room. If you shine a flash light at the wall you will have the same effect.

BTW you still have to be careful with LEDs. I recently shone mine at my LPM with an aspheric from close up and it registered +500 mW so effectively class 4 lol :p The LED is however a point source, so the light power should follow the inverse square law, and should only be really dangerous at very close range.

Lasers have a collimated beam until the beam undergoes diffuse reflection. From there on out the beam is scattered all over the place ie no longer collimated and much like the light directly out of the flashlight.:beer:
 
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Livinloud

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Yes it is being difused thus lighting the room but thats still a reflection. Its not the same as hitting a mirror but none the less still dangerous. Indoors you never use a laser without glasses and outdoors you can when being super careful.

Forgot about aspheric flashlights. Those things are pretty beastly attachments!
 

grainde

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Indoors you never use a laser without glasses and outdoors you can when being super careful.
Actually you should all ways be super careful, but you dont necessarily have to wear goggles indoors. Yes you should if you have no idea what you are doing or how the laser will interact with materials. If you understand what you are doing and follow some simple rules you can lase without them. Im not saying goggles are redundant, but I am saying they are not always necessary.

Here are some guidelines:

Disclaimer: Im not recommend this, its what I do and I am extremely careful. I also know a lot of people dont use goggles, even though they say they do, so maybe these points will help as a guideline. Pls note: Anything above 5 mW, can be dangerous and cause permanent eye damage...

I occasionally use my 100 mW 405, 200 mW 450 and 250 mW 650 inside and dont wear goggles. I do however make sure;
1) I dont scan
2) That nobody is in or could get into the path of the beam
3) That there are no reflective surfaces
4) I know where the beam will terminate before switching on
5) I am ready to switch it off immediately ie never leave any laser unattended
6) I pick a surface more than approx 3 meters away
7) I never look at the dot
8) I also try to pick out a complimentary colour if there is nothing matte black for the laser ie dark red/ orange or brown for the blue and 405 and I choose something more blue or black for the red.
9) I also try to hit the surface at an angle of less than 90° (angle of incidence = angle of reflection)
10) Its also best to leave the lights on.

I always use goggles when burning, no matter what power and I always use them for lasers of any higher power and with my IR laser. Nobody is allowed in the same room, if Im using goggles and I warn everyone before hand.

Yes safety goggles are recommended and if you dont have any experience and cant figure out where the beam will go then wear them.

:beer:
 
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Livinloud

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i know its possible to use lasers inside without glasses but to me, its not worth it right now. im working on constructing a cube/pyramid beam stop to enclose the dot and make it safer to use inside but until then, its not worth it. i know i can safely use a laser without glasses but it only takes a slight error and your eyes are screwed. too many people have screwed up their vision and even experienced vets have done this

When i get my enclosed beam stop constructed i will post it here for everyone to use :beer:
 

Pi R Squared

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Chocolate and beer don't mix, chocolate beer and lasers are a deadly combination.

Some people may think its safe to use high powered lasers without safety glasses if your careful and know what your doing, but its never completely safe. Safety glasses are also meant to protect you from accidents, and accidents do happen. I remember reading a thread here a few months ago where someone was using a 2 or 3 watt laser and it fell and rolled off a table and he took a direct hit in one eye. Luckily he was wearing his safety glasses and had no damage to his eye, only a burn on his face. Here in western Washington we get an earthquake from time to time. I can just imagine one day using a laser and an earthquake hits while I am not wearing safety glasses and the laser falls and rolls of the table and hits me in the eye. My point is accidents only happen when you don't expect them.

Alan
 

Livinloud

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^^Hence why i always use my glasses unless outside and being ultra careful :beer:
 

KapHn8d

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It is the catch 22 of laserist enthusiasm. I *love* looking at laser beams… they captivate and fascinate my imagination. We have technological access to high powered lasers sufficient to produce visible beams is clear air… some even during well let ambient conditions… yet cannot enjoy them with the naked eye. It makes me really think of how to learn and find creative ways to capture them on film to enjoy later sans glasses. It is my understanding that if you are shining into clear skies with no clouds, you can safely view the beam of any of today’s handhelds and pointers without glasses, but I’m not brave enough to do it. It’s just low power pointers and fog for native beam view for me until further notice. Outside that, I already own 3 safety glasses and have my eye on a couple more as near term purchases. Vision is priceless.

To the OP - I hope you made it through this with a lesson learned and no long term damage. Next time, be safe.

Cheers,
c
 

Livinloud

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Kap,
im with you on safety all the way so +1 for being a safety advocate with me!
HOWEVER i can confirm that you can use your laser outside in a clear sky with no problems, as long as you know there are no obstructions i.e. wires, branches, etc..... ive done it many many many times with absolutely no issues or problems. best way to do this is buying a tripod and clamp to ensure the laser will stay pointed where you want it. if you still dont feel comfortable with it then no problem, i understand the caution
LL
 

EpicHam

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So as long the spot where the laser hits isn't in your vision cone and you are only getting diffused reflections
It should be done.
BUT NOT THE SPOT OR ITS DIRECT REFLECTION!!!
 

thunderdome

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So as long the spot where the laser hits isn't in your vision cone and you are only getting diffused reflections
It should be done.
BUT NOT THE SPOT OR ITS DIRECT REFLECTION!!!
I did not understand you entirely.
With a 50-80 mW laser I cannot look at the spot (the blue dot in the wall)?
Direct reflection and direct beam I understand.
 




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