Laser Dot Danger

nikokapo · Oct 7, 2009

lasersbee said:
Yes... Albert... IT IS DANGEROUS... (again... depending what distance you are from
that white wall)... without Laser Safety Goggles...

That's what most of the above posts state....

Jerry

^ This.

Distance does matter, but if the wall is white or tends to have a white colour then it can be proven with common geometrical optic physics. Just trace the beams, some of them will come back in the direction of your eyes because white reflects all wavelengths.

I can expand this later if you want, I've gotta run!

Asherz · Oct 7, 2009

While safety goggles are a must, I've never seen the point in buying a green pointer just to wear goggles and see a dim white spot on the wall through the glasses... I'd rather enjoy the beam.

If I'm burning then yes I wear goggles, but as long as you are careful and have some common sense then you should be fine.

hakzaw1 · Oct 7, 2009

What about using an old 8mm movie projector screen for lumia. spiro etc. The second hand shops are practically giving them away= I have three 'regular' sized ones and I got a 8footer from a hotel 'garage' sale($5) that I attached to the ceiling in my 'laser room', makes even low powered beams show nicely and when I dont want to use it it rolls back up. Another 'hakzaw1 find of the day'-- thanks to all for your opinions. ;-) Len

hakzaw1 · Oct 7, 2009

Am going to repost the last question of mine in its own thread -dont want to be a threadjacker which i guess is worse than a double-poster. Len

Lasher · Oct 12, 2009

I'm new to Lasers and am in no way a laser science expert.

I would think from a common sense perspective that any light source, be it Laser or some other type that makes you blink or feel the desire to turn your eyes away from it is in some way dangerous to your vision.

After all our eyes and brain were designed to protect themselves as an auto response to any danger.

We don't have to stick our head in a fire to know its not a good idea.

Trust in your instincts if it hurts to look at it....Don't Look At It!

Just my .02
Lasher

Trevor · Oct 12, 2009

Lasher said:
I'm new to Lasers and am in no way a laser science expert.

I would think from a common sense perspective that any light source, be it Laser or some other type that makes you blink or feel the desire to turn your eyes away from it is in some way dangerous to your vision.

After all our eyes and brain were designed to protect themselves as an auto response to any danger.

We don't have to stick our head in a fire to know its not a good idea.

Trust in your instincts if it hurts to look at it....Don't Look At It!

Just my .02
Lasher

Never truer words were spoken... "Doctor, doctor - it hurts when I do this!"

"Don't do that!"

-Trevor

Sybiria · Dec 3, 2009

well if it already hurts the damage will be done then! So take your precautions so as to have both your eyes

Marcusss · Dec 4, 2009

Bad ass calculations going on here that hardly make sense to me, yet... pah.
I managed to conclude looking at the sun or into a laser beam is bad, muhaha just joking ofcourse I know that

knorkneutel · Dec 6, 2009

If I play with my 150mW Jayrob green laser and shining onto mirrorballs and using kaleidoscopic tips on a party I can be dangerous for other people's eyes?
( I used my 100mW Jayrob green laser on party´s but never shine into the public)

Is there anyone who had eye damage from green lasers? Sometimes I think i've a little eye damage when playing on reflections like mirrors , but i hope its not

. The light can be soo bright I think its not good for the eyes

Trevor · Dec 6, 2009

knorkneutel said:
If I play with my 150mW Jayrob green laser and shining onto mirrorballs and using kaleidoscopic tips on a party I can be dangerous for other people's eyes?
( I used my 100mW Jayrob green laser on party´s but never shine into the public)

Is there anyone who had eye damage from green lasers? Sometimes I think i've a little eye damage when playing on reflections like mirrors , but i hope its not . The light can be soo bright I think its not good for the eyes

Unless the kaleidoscope tip perfectly splits the beam 30+ ways, a dangerous beam can still reflect off the ball into someone's eye.

-Trevor

LSRFAQ · Dec 7, 2009

Book with the real math in simple terms. Btw, the scattering is Cosine, not Gauss. btw, 5 mW of vis would not hurt you 1 out of 99,999 times, 15-20 mW is about the lesion threshold. Medical laser aiming beams for eye work are 3-5 mW or so. remember UV and IR injury mechanisms can be far different. The Class IIA standard at .95 mW is sized so your blink reflex protects you. IIIA at 4.95 mW is sized so you only have a potential injury one in N times. I think N is 9,999 or 99,999 but I'd have to look that up.

FREE DATA AND FORMULAS FROM UNCLE SAM:

http://www.army.mil/usapa/med/DR_pubs/dr_a/pdf/tbmed524.pdf

You really have to make measurements for each kind of scattering material and you need to factor in TIME duration of exposure, its NOT a simple threshold power calculation. The math is not hard once its laid out for you. That book also has the exposure tables for time vs wavelength.

Start at page 114 for scattering.

And YES A 100 mW JAYROB WILL do eye damage with a direct hit , a reflection off a mirror, or a near hit from a scattering surface.

Steve

davidgdg · Dec 16, 2009

LSRFAQ said:
...And YES A 100 mW JAYROB WILL do eye damage with a direct hit , a reflection off a mirror, or a near hit from a scattering surface.

Steve

Not from a scattering surface it won't (assuming you mean non-specular). You need mult-watts for non-specular reflections to be dangerous.

LSRFAQ · Dec 21, 2009

davidgdg said:
Not from a scattering surface it won't (assuming you mean non-specular). You need mult-watts for non-specular reflections to be dangerous.

-----------------

OH, that so? Do the math. 3B starts at 250 mW vis for a reason.

Not to mention poor blink reflex at 405.

Steve

Moptsp · Dec 23, 2009

I never shine a laser directly onto an object (where I'm 90 degrees from the beam angle/parallel). Even if it's <5mw. You can take a green laser and shine it at an angle to a wall and see the reflection quite well. If this reflection hits you, it's going to hurt. With 100mw, I'm sure it could really be dangerous if the reflection hit you. Though if your at an angle where the beam path reflects else where, it wouldn't do instant damage (at least I believe), you would have to stair at it, as if you would the sun. But that's just stupid.

-Moptsp

Raybo · Dec 24, 2009

knorkneutel said:
If I play with my 150mW Jayrob green laser and shining onto mirrorballs and using kaleidoscopic tips on a party I can be dangerous for other people's eyes?
( I used my 100mW Jayrob green laser on party´s but never shine into the public)

Is there anyone who had eye damage from green lasers? Sometimes I think i've a little eye damage when playing on reflections like mirrors , but i hope its not . The light can be soo bright I think its not good for the eyes

YIKES!

Bluefan · Dec 26, 2009

davidgdg said:
Not from a scattering surface it won't (assuming you mean non-specular). You need mult-watts for non-specular reflections to be dangerous.

INCORRECT

Just to sum it up for visible lasers:
- class 2: <1mW: safe because the blink reflex works fast enough to prevent damage in case of a direct hit. Specualr reflections are no problem.
- class 3a: <5mW: most of the people here consider it safe, with a proper working blink reflex you can mostly avoid damage, but I'd use goggles around >3mW. Specular reflections are safe.
- class 3b: <500mW Direct hits do damage with no second chance. Glossy surfaces are a serious problem, even a reflection from glass window at normal incidence (2x 4%) can be dangerous, at an angle the reflection will be much stronger. Glossy surfaces can easily reflect 10%. True specular reflections are safe, but above 200-300mW I'd avoid even a true specular reflection, just to avoid the headache.
- class 4: >500mW direct hits give massive damage, but even true specular reflections give damage to your eyes. Always goggles on here.

(Count reflections from a mirror as a direct hit)

Laser Dot Danger

nikokapo

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Asherz

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hakzaw1

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hakzaw1

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Lasher

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Trevor

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Sybiria

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Marcusss

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knorkneutel

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Trevor

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LSRFAQ

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LSRFAQ

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Moptsp

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