Blu-Ray laser safety/damage??

[Jaseth]

Albert what have you been smoking? It's obvious that nobody should ever just wave a laser randomly around the room.

 

[Deleted member 8382]

waving it around in the dark

Maybe we understand different things from the same sentence. I understand this means that they were a group of people and he was pointing it to dark zones, and the guy was afraid looking at the bright dot might have been harmful. People with blue or green eyes use to feel pain when looking to bright things, so I asumed this is what he described as "headache".

I think you are understanding that the guy was randomly pointing it to a dark area in which the people was, so that the laser could have gone in their eyes, although I can't read that he said anything like this!

It usually happens to me that I'm pointing somewhere around me with my laser and someone says "hey stop it please it's gonna blind me", but just because they think looking at it will harm them.

Yours,
Albert

 

[Meatball]

especially in the dark... where one could not see where to avoid aiming to avoid hitting eyes..

 

[davidgdg]

Albert what have you been smoking? It's obvious that nobody should ever just wave a laser randomly around the room.

Except that of course that this is pretty much exactly what happens with disco laser shows. I'm not condoning reckless use of pointers, but we need to keep the risks in perspective. Laser injuries are almost invariably from multi-watt lasers in an industrial or military context. Injuries even from high power hobby pointers are vanishingly rare.

 

[Deleted member 8382]

what has disco lasers to do with this? Disco lasers are scanning all the disco at madly high frequencies, a hit in your eye from them lasts literally milliseconds.

One hit from 1W laser at 1Khz shoots in your eye the same energy than 1mW laser for 1 second.

Laser shows are pretty well regulated, I don't know what was your point.

Yours,
Albert

 

[davidgdg]

what has disco lasers to do with this? Disco lasers are scanning all the disco at madly high frequencies, a hit in your eye from them lasts literally milliseconds.

One hit from 1W laser at 1Khz shoots in your eye the same energy than 1mW laser for 1 second.

Laser shows are pretty well regulated, I don't know what was your point.

Yours,
Albert

I doubt that it is valid to make the comparison in this way since you have to take into account the abiility of the eye (in particular the blood vessels in the retina) to dissipate heat. 1W for 1millisecond is thus likely to be more hazardous than 1mw for 1 second.

As for exposure times, if a laser pointer is being waved around so that the spot is moving at (say) 2 to 3 m/s relative to the eye then the duration of the "hit" (assuming a partially dilated pupil) is about 1 to 2 milliseconds which is not that different to the duration of a single exposure at a laser show. Although people assume that the main protection from accidental exposure is the blink reflex, in reality it is more likely to be the motion of the pointer. To achieve a sustained exposure of even one tenth of a second at any kind of distance is very difficult. You can test it yourself. Draw a circle 5mm wide and then try to hold a laser spot on it from a distance of 10 feet. Almost impossible for more than a fraction of a second. I am not of course considering self-inflicted or deliberate injuries at close range, which are a different matter.

The point about laser shows is that they use relatively high powers - up to 2.5 watts at the aperture. And yet there are hardly any reports of eye damage. That was essentially my point. Whilst it is sensible to use conservative safety limits, I think the fact remains that the objective risks posed by pointers are probably rather lower than people think.

Brgds

David

 

[Benm]

dont worry even 200mw of blu ray reflected and thus unfocused may not blind you due to the blink reflex

I would not trust the blink reflex on 405. Bluray is so close to invisible that any blink reflect would be very slow or even not present compared to equal exposure to 635 or 532.

The blink reflex depends on something actually lookin bright, not on any mechanism within the eye itself that detects an 'overload' situation. Considering that, the safe limits for visible lasers might not apply to borderline wavelengths all that well. One would be more likely to sustain injury from playing with a 200 mw bluray than with a 200 mw green - the latter is just 'so darn bright' that you probably will not even want to look at the spot on a wall for long.

 

[wolfram]

It is true that the damage from a<10mW purple may not seem impressive , but the The question to be asked- How long exposer, What type of wall paint. The concentration of photons ( this expresess the angle of insodence )with each reflection.
Wear safetey glasses And ,BE CAREFUL care full , Ask questions !
Im not very frequent, and not very rep , But I have been here since 2008. I work in a scientific enviroment. I have some experience.
I just enjoy reading .
You can ask me questions. But if I dont know, We can ask our family. LPF!

 

[davidgdg]

It is true that the damage from a<10mW purple

To be mildly pedantic, it is not a "purple", it is violet. Purple is a non-spectral colour combining red and blue. Violet is the name of the spectral colour produced by 405.

 

[davidgdg]

I would not trust the blink reflex on 405. Bluray is so close to invisible that any blink reflect would be very slow or even not present compared to equal exposure to 635 or 532.

405 is certainly much less visible compared to 532 (by probably a factor of 50). But a direct exposure to even a low power 405 would still look brighter than the sun and certainly enough to trigger the blink reflex.

I think the issue with 405 is not so much the blink reflex, but rather prolonged staring at the spot when burning. Because the spot seems so much less bright than green, there might be an increased risk of doing some damage from close range reflections over a long period of time (say a minute or more). The same is true for IR but obviously to a much higher degree. That's why I always used goggles for BR burning, even though the spot doesn't appear bright enough to warrant it. Ditto for red .

 

[wolfram]

Hello , I stand in correction! You are of course correct that violet is the appropriate description as it pertains to the primary prismatic set (ROY G. BIV) and its spectral frequency designation.
It looks of course to me as Porple ....Im a little color blind.


Thanks for the correction I sometimes forget that the translation is every thing.

Wolfram

 

[More Power]

Bit of an over reaction, diffuse reflections from a 5 mw pointer simply wont hurt you.

 

[mfo]

Bit of an over reaction, diffuse reflections from a 5 mw pointer simply wont hurt you.

Stop with the necro-posting holy shit man.

 

[More Power]

Necro?

 

[daguin]

Necro?

Pulling up old, dead threads.

Peace,
dave

 

[More Power]

OK, i understand i wont...
i didnt know that was bad and that i was even on an old thread. i got it now sorry.