A plea for safety, pl edition.

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If you want to have a clean conscious and be responsible, including pictures and educational material on how to calculate power density at a distance pertaining to the 445nm diode.

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We have done that several times on PL. I'll ask Spec to make a sticky for it.

Getting the copywrited ANSI lookup table requires you to purchase the Z136 standard. However It is available for free, I've posted the file here, and on LPF many times before, A excellent copy of the chart is in Army Medical Publicaton TB 524

Attachment 17534

Which is available here: http://chppm-www.apgea.army.mil/laser/Main.html

Or by goggling "Army Laser Safety"

The calculation examples are in Appendix B on Page 111 and the tables for wavelength specific numbers start on Page 207

The CDRH's own Audience Scanning Calcs are here, from the last flame war we had about calculation methods on PL:

http://www.photonlexicon.com/forums/...ing%20mixedgas

A reduced function on line calculator is here:

http://www.laser-professionals.com/p....php?pageid=54

It has issues with short distances and non circular beams however.

PL user DOC has a spreadsheet here:

http://www.photonlexicon.com/forums/...5&d=1261568920

Again, for mainly circular beams.

Caveats, Measuring divergence is problematic in a multimode broad stripe laser diode such as these. Most simple methods assume TEM00 mode, and these are ANYTHING BUT TEM. Good methods involve a power meter or photodiode, a translation stage and a knife edge. Otherwise it is difficult to make accurate assumptions based on shining the spot on the wall and using a ruler to guess the 1/e^2 points.

Understanding the math is problematic for most people. Rob, why don't you write a JAVA calculator and stick it on line some place.

445 is in the actinic range, as is 405, so the hazard number is a bit different then the straight visual table.

Steve

The simple solution is either sell them, or don't sell them. Do what you think is right. The reality is that anyone can buy one of these projectors and part it out and that opens the door to people selling diodes on ebay, other forums, craigslist, newsgroups, and everywhere else with no trouble. Making PL group buy rules will only prevent people on PL from selling diodes to other people on PL. And since PL members are typically pretty informed about laser safety, that means whoever is selling them on here probably knows what is going on, and whoever is buying them on here probably knows what is going on. So, make rules for being ILDA members and whatever else is suggestions just is pretty silly. They'll just go next door and buy them.

Safety is always a concern. But, diodes have been sold for years at power levels that can cause serious damage. I just think it is kind of silly, and mostly self serving, how this discussion is going in this thread.

No offesne to anyone, I hope. I'm just trying to be the voice of reason and reality.

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Originally Posted by dsli_jon

Don't let the lure of making a quick-buck, allow you to be part of what *could* turn-out to be a disaster.

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Jon, that factor has exactly 0% weighting in my mind; as I don't make a penny...
Appreciate the other advice...

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Originally Posted by JohnYayas

The simple solution is either sell them, or don't sell them. Do what you think is right. The reality is that anyone can buy one of these projectors and part it out and that opens the door to people selling diodes on ebay, other forums, craigslist, newsgroups, and everywhere else with no trouble. Making PL group buy rules will only prevent people on PL from selling diodes to other people on PL. And since PL members are typically pretty informed about laser safety, that means whoever is selling them on here probably knows what is going on, and whoever is buying them on here probably knows what is going on. So, make rules for being ILDA members and whatever else is suggestions just is pretty silly. They'll just go next door and buy them.

Safety is always a concern. But, diodes have been sold for years at power levels that can cause serious damage. I just think it is kind of silly, and mostly self serving, how this discussion is going in this thread.

No offesne to anyone, I hope. I'm just trying to be the voice of reason and reality.

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John,
That fully summarised the conclusion of my thought process...
Spot on...

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Originally Posted by mixedgas

You have been warned. You can also bet I and others will be calling Casio first thing Monday Morning.

Steve

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I agree with everything you say Steve apart from this.

Why take away from people the only cheap source of projector blue there is?

I personally hope that all diodes in all colours become this cheap as this is thje only way forward for the hobbyist side of the industry which unfortunately currently excludes many people because of the sheer cost of projector construction.

To call for Casio to make these diodes non removeable is like calling for cars to be made no driveable in case some idiot should choose to drive them recklessly. Its simply overkill.

A far better solution is to step up the calls for responisble policies when making these into pointers over on the LPF.

Even if you manage to get Casio to exceed to your demand I don't see it stopping anything. Someone in China is reading this now who will know how to get those diodes from the supply chain way before Casio ever put them into projectors and you can bet your bottom dollar that even if Casio do make them non removeable, a whole flood of Chinese manufacturered high power blue laser pointers are already on their way to the worlds market places and there's nothing you or I can do to stop them. Bottom line is, Casio making the diodes unavailable will only affect the genuine hobbyist or LP enthusiast. Everyone else will just buy pre-manufactured ones from Far Eastern countries off ebay where there's no reliance on projector harvesting to obtain them

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Originally Posted by mixedgas

You can also bet I and others will be calling Casio first thing Monday Morning.

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While I agree with your sentiment, I think you are overreacting here. Remember that IR diodes MUCH more powerful than these have been available on ebay for years. Has anyone been calling coherent asking them to have their FACs self destruct when removed? The sky's not falling, only the price of blue :)

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Originally Posted by danielbriggs

Jon, that factor has exactly 0% weighting in my mind; as I don't make a penny...Appreciate the other advice...

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Well, sorry for that, but comment was not *directed* at you, per-se, but relevant to this 'topic' in-general, since, clearly, there are others, here, and on other forums, making at least SOME profit off these 'harvests' - but it's not about the money as-much-as 'individual responsability' in the safety-education chain.... 'to-sell or not-to sell' is not as much of 'the question' as WHO they're sold-to, imho...

KNOW YOUR BUYER / thier 'qualifications', was my only point... :cool:

cheers...
j

IR is not sexy, and those FAP/FACs wont run off sub C lithiums.

I did not call Casio yet, I've called some one else, and this will go through proper industry channels.


Steve

I can't really see anything happening if it requires any redesign or really anything that costs money. These concerns affect an exceedingly tiny portion of the world's population and therefore Casio Computer Corporation's customer base, and the projector isn't breaking any laws. By this logic, 12X blu-ray burners should also have non-removable diodes.. they don't. I do think that cutting the hobbyist off from these completely because of concerns that have not (and may never) come to fruition is a gross overreaction. This debate sort of parallels the whole crowd-scanning thing: Lot's of people are very scared and nervous about something that in reality has caused an extremely tiny number of reported incidents, even including a margin for error.

If my hobby requires a ILDA membership, so that I can continue using a large projector that needs an even larger flight case for transportation, 240v power, and a laptop to control, then so be it, I shall obtain such cert.

If at any venue I notice a powerful hand held pointer in any spectrum, my gear will be immediately shut down until the offending laser pointer is found, confiscated and the owner ejected from the premises.

Laser safety is the ownership of the laserist at the venue. The buck stops with them.

If the entire laser display is ruined by one idiot with a laser pointer, so be it.

Yes, we need to be more vigilant in this regard with these cheap 445's, this is why I am watching you all closely to see what options you all come up with.

This is coming from a new member to laser projection. (One that has no desire for laser pointers)

while I agree with your warnings, this

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You have been warned. You can also bet I and others will be calling Casio first thing Monday Morning.

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struck me as a bit odd, who died and left you the laser police?

I guess we should ban DVD-Burners cause they have low-divergence high power 650nm diodes... and god forbid those evil blu-ray burners with their couple hundred mW of 405... etc

I mean hell, I can walk into any gun store and buy a pistol and walk right out the door with it... with some paperwork I can buy a grenade launcher and grenades... machine guns, 50 caliber rifles etc...

seriously making a big stink out of this is just going to ruin it for everyone...

I guess this hobby should only be for the rich as far as your concerned? since that seems to be the bar... after all anyone that can afford it MUST be safe with it right? hence all the dee dee dees that bought 1W green laser pointers etc...