Did you miss this?

No, why would you think I did?

 

OK, starting with my application in our product, those THREE MILLIWATT laser modules were able to produce a bright spot on the house across the street, about 160 feet away, that was obvious in bright daylight. At that distance it was several inches in diameter. By keeping the power lower you are under a less strict set of rules, and in addition can use a less expensive laser assembly. And a laser of a much higher power rating, the price will be a lot more.
As for the comment about the laser gun-sight, evidently a bunch of folks had no clue. I had no intention of minimizing any hazard, just pointing out that hazards are relative. Fast moving metal at 100 yards is very dangerous, a 3 milliwatt laser at 100 yards is still visible.

 

OK, starting with my application in our product, those THREE MILLIWATT laser modules were able to produce a bright spot on the house across the street, about 160 feet away, that was obvious in bright daylight. At that distance it was several inches in diameter. By keeping the power lower you are under a less strict set of rules, and in addition can use a less expensive laser assembly. And a laser of a much higher power rating, the price will be a lot more.
As for the comment about the laser gun-sight, evidently a bunch of folks had no clue. I had no intention of minimizing any hazard, just pointing out that hazards are relative. Fast moving metal at 100 yards is very dangerous, a 3 milliwatt laser at 100 yards is still visible.

You might note that “<5mW“ laser pointers from China have been tested exceeding 150mW! It now costs very little to hurt yourself. In the US, the FDA regulates laser products. Their standards incorporate the IEC- definition of a “safe laser” by reference. In the FDA guidance on compliance with lasers in toys, it says:

The following are examples of children’s toy laser products:

• Lasers mounted on toy guns that can be used for “aiming”;
• Spinning tops that project laser beams while they spin;
• Hand-held lasers used during play as “light sabers”;
• […]

IEC 60825-1, which is the international standard as well as the ANSI standard defines a Class 1 635nm laser as not exceeding .35mW! These ratings are based on wavelength, and are for CW, collimated beam lasers. The mechanisms for eye damage by lasers varies by wavelength as well based on which part of the eye absorbs the light energy.

But, an eye-safe red laser with a collimated beam is considered <1mW, and a 3mW laser is consider a potential eye risk if for any reason the blink reflex doesn’t shut it out quickly enough (it normally would). But, in the case of a blink failure, permanent retinal damage is possible.

Now, Bill, I don’t imagine for a moment that given the facts you would ignore the hazards. But I know that I wasn’t aware of just how much potential danger laser diodes offer. This is for a variety of reasons, not the least of which is that the ratings on Chinese laser products are completely unreliable on the order of two or three magnitudes in some cases!

It is also true that the danger is not is being lit up at 100 yards, but by careless handling at only a few yards. My point is, in general, the relative magnitude of the dangers (projectile vs. photons) would only be relevant if one was being ignored for the sake of the other (e.g.: “Don’t worry about the projectiles, we are using an eye safe laser!”, the inverse of your own statement‘s bald in terpretation.

It is a common mistake to argue in this fashion, and is called a “red herring”. Introducing an irrelevant but related fact to shift the focus away from the original point. Yes, projectiles are dangerous to eyes and laser sights on projectile weapons are in close proximity to the arguably more dangerous projectiles making them appear related.

But while you apparently did not intend to dismiss the potential hazards of lasers by phrasing things as you did you could easily convey the idea, to the unseen reader of your post, that those hazards can be set aside as trivial or irrelevant. On the other hand, you have continued to argue that such lasers are probably perfectly safe at some great distance from the gun.

This is a repetition of the red herring since the safety of the lasers at the limits of the dangers of the projectiles is irrelevant to the dangers of the lasers at ranges to which a person could be exposed (e.g.: the handler of the gun and those nearby). I understand that you might not realize just how dangerous lasers can be, I didn’t either.

But while the incidence of permanent injury from ~5mW handheld lasers is quite low (best sources I can find are >5 <10 per annum) they do occur. And, to your point that projectiles are more dangerous, this is undoubtedly true—reports of non-firearms projectile weapons (i.e.: BB and airsoft guns) run in the tens of thousands (~30,000).

But, the dangers of projectiles should be apparent even if they are (often) ignored because the shooter “didn’t expect that to happen” or because the victim eschewed eye protection because it was inconvenient or otherwise unattractive. But at least eye protection in that case is expected. People don’t even recognize they should be wearing laser eye protection at levels around 5mW, but they should.

So with this I will drop this subject. It is a deviation from the TS’ intentions, and I really don’t want to set you up as a bad guy who doesn’t care about safety—I don’t think that for a second. I do want to make sure any future reader of this thread has the facts on laser safety so they can judge for themselves what measures to take.

As always, you have a lot of excellent information to provide; thanks to your extensive real world experience you often have exceedingly practical advice that should be taken seriously. I admire the depth and breadth of your ability to contribute to these threads and always look forward to hearing from you.

I apologize if my concern about safety came across as a personal attack or a criticism of you in particular—it was certainly not meant to be that.