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ArcticMyst Security by Avery

Is there a "safe" output range for glasses-free operation at this wavelength?

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Is there a "safe" output range for glasses-free operation at this wavelength?

Hi guys. Pardon the noob questions. I'll be brief.

Looking for a 445-450nm pointer in a "safe" but still visible output level. Does such a laser exist? Can it be had in a host/shell that doesn't look like a cheap Chinese ink pen?

The best I've found (thanks in part to suggestions found here) is the HL450 - 100 on laserbtb. HL 405,445,450nm

This one is rated at 100mW output, but honestly I don't have enough experience with this wavelength to know if that's sufficiently low to be used (safely) in and around the home without goggles. It's my understanding that the blue/violet lasers require a bit more power to be visible in daylight and typical daytime conditions. I'd be happy with a 4.5-4.9mW pointer if I could reliably see it and the device itself looked reasonably presentable.

Am I completely off my rocker here? For the record I have read LSRFAQ's "plea for safety" thread and several others. This site is a great resource. Thanks for indulging me.
 





ARG

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Re: Is there a "safe" output range for glasses-free operation at this wavelength?

It really depends on how safe you want to be. Just keep in mind safety depends on power density, not power.
If you have a 5mW pen laser with a tiny beam it is much more dangerous than a 10mW laser with a large beam size.

Laser safety - Wikipedia, the free encyclopedia

IEC60825_MPE_W_s.png


Wikipedia said:
The maximum permissible exposure (MPE) is the highest power or energy density (in W/cm^2) of a light source that is considered safe, i.e. that has a negligible probability for creating damage. It is usually about 10% of the dose that has a 50% chance of creating damage under worst-case conditions. The MPE is measured at the cornea of the human eye or at the skin, for a given wavelength and exposure time.

Personally I would recommend something from laserglow, the laser will be within the specified power range that they state. You don't know what power of laser you'll get from other places.
 
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Re: Is there a "safe" output range for glasses-free operation at this wavelength?

OK, would it help to assume a beam diameter of ~2.5mm @ aperture?

If I'm reading your graph correctly, we're mostly looking at the green line?
 
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ARG

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Re: Is there a "safe" output range for glasses-free operation at this wavelength?

Yeah, the green line is the visible spectrum which is all that really matters for this discussion :)

As your power density increases, you'll get more visibility, but the maximum exposure time goes down.
Really, the choice it up to you. How safe VS how visible you want your laser to be, it's a trade off :p

Tell us more about what your application is.
Do you need a visible beam? In what lighting conditions?
Or do you just need a visible dot? From how far away?
 
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Re: Is there a "safe" output range for glasses-free operation at this wavelength?

My application is general purpose/novelty. I would only expect a visible dot out to 50ft in daylight, slightly longer indoors in normal lighting conditions. Beam visible only at night or in relative darkness. Not doing anything particularly scientific with it, so my requirements are pretty low.

I'd order from LaserGlow (and have in the past) but their Hydra-5 is completely unimpressive, especially at $280. Which is why I started looking at the laserbtb offerings. Again, I'd be completely happy with a Class IIIa device if I could find one I liked from a reputable dealer.

I'm calculating MPE on the HL 450 at 2.04 W/cm² @ aperture, which puts it well outside the safety range according to your graph. :(
 

ARG

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Re: Is there a "safe" output range for glasses-free operation at this wavelength?

Getting a beam directly in the eye is rare. Most of the time it's because of a reflection which means you'll have a lower power going into your eye, and most of the time it will diffuse the beam. If you're careful with where you're pointing it'll be fine. Common sense applies.

I've only ever had one direct beam to the eye, but I was doing alignment with goggles. The number you calculated would be for a direct hit.
 
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Re: Is there a "safe" output range for glasses-free operation at this wavelength?

There is no such laser as safe :crackup:
 

Things

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Re: Is there a "safe" output range for glasses-free operation at this wavelength?

Anything under 5mW is sufficiently safe, even for a direct hit without goggles, though as ARG said the blue end of the spectrum isn't nearly as visible as green. That said a blue laser dot should still be easily visible at 50ft at 5mW. Is there any particular reason you want blue? If it's just for novelty then you'll probably enjoy green more for it's brightness. A 5mW 532nm beam is still quite visible in the dark.
 
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Re: Is there a "safe" output range for glasses-free operation at this wavelength?

u should look on laserbtb they have also 450nm in the pen style host and lower power 1 and 5mW i would say those would be pretty safe and no goggles needed but you still should use a low mode lasers with care.
LP 450nm 1-80
 
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BowtieGuy

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Re: Is there a "safe" output range for glasses-free operation at this wavelength?

A good idea, but I think the OP is looking to stay away from the "pen" style hosts.
 
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Re: Is there a "safe" output range for glasses-free operation at this wavelength?

There is no such laser as safe :crackup:

Hence my "quotes". ;)

Anything under 5mW is sufficiently safe, even for a direct hit without goggles, though as ARG said the blue end of the spectrum isn't nearly as visible as green. That said a blue laser dot should still be easily visible at 50ft at 5mW. Is there any particular reason you want blue? If it's just for novelty then you'll probably enjoy green more for it's brightness. A 5mW 532nm beam is still quite visible in the dark.

I have 2 in green already (I think both are 532nm) including 1 from LaserGlow they apparently don't make anymore. Both are class IIIa. I enjoy them but I've been curious about the blue shades for a couple of years now and noticed recently that they've become incredibly popular, so I started looking around.

A good idea, but I think the OP is looking to stay away from the "pen" style hosts.

I am. My experience with them has been poor. I was hoping to find something in machined aluminum, similar to the repurposed flashlight bodies I see people using. Just a little more substantial than the pens.

Here's a question: Do you think any of the custom builders would entertain a build order for a 5-10mW pointer with a 445nm diode, or is that too small potatoes? Something with a CR123A cell would be awesome.

Thanks for the replies guys. I appreciate it.
 

Things

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Re: Is there a "safe" output range for glasses-free operation at this wavelength?

I'm sure someone here could build one, it's not really any different to a higher powered laser in terms of construction.
 
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Re: Is there a "safe" output range for glasses-free operation at this wavelength?

It might not be possible to get 5-10mW out of
one of the cheap blue diodes. Higher power
diodes tend to jump up over 10mW when they
hit threshold. A true 5mW blue diode would
have to be sourced from one of the premium
distributors if there even is such a thing.
 
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Re: Is there a "safe" output range for glasses-free operation at this wavelength?

Forgive my lack of memory of the diode model number, but those low power ~125mW 450nm diodes can be run at 5mW without issue. I set one up like that a loooong time ago when blues first hit the market. IIRC lasing threshold was somewhere around 2.8mW.
 
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Re: Is there a "safe" output range for glasses-free operation at this wavelength?

Okay, was it a PL450? That would be the thing
to look for then.
 
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Re: Is there a "safe" output range for glasses-free operation at this wavelength?

It probably was. Idk for sure. I did this back before DTR started carrying them. I was ripping them out of the pens LaserLands sold.
 




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