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Best way to validate safety claims of 3rd party?

EngineerVsMBA

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Oct 3, 2018
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How can I validate the safety of a 3rd party laser based system in the IR range? Are there FDA related test houses for Lasers? Standard measures or tests for safety? Standard design houses that can help? (Edit: this is to validate some of the use-cases listed here: https://www.wi-charge.com/)

I am a EE that has a vendor that is promising amazing results with lasers, and they want to integrate their hardware into my device. Based on their specifications, it looks like a 100mW to 1 watt laser.

This device will sit in a consumer environment, with a beam in open air, and the vendor claims to have a feedback system that prevents any eye damage or fire damage. I'm concerned that the vendor may not have done his due diligence on reflected laser safety, and I'm not sure his feedback mechanism is fast enough to guarantee safety if something goes wrong.

Since every vendor has some kind of dirty secret, I've been asked to create a safety / validation test plan. I have a budget, and would love to create a test setup in the $1k-$10k range, or, send it to a professional who already has a setup. We are open to university partnerships (those take MONTHS to set up) or consultants. Any suggestions?

I'm extremely comfortable designing things for FCC, UL, and other high-voltage / high RF worlds, but I'm not familiar with the world of Lasers. Is there a similar standards body that I can hire/consult with?

Power Meters look like a good start for measuring direct power, but I'm concerned about indirect exposure as well as direct exposure. It looked like a good start, but I would love some suggestions around reflected safety. Specifically, 4 concerns:
  • Reflected Light: Their surface absorbs the light, but what if the angle of the beam allows more reflection than they were anticipating? (Eyeball damage). What if the "edge" of the laser gets reflected (or absorbed) by the housing, causing a reflection. (fire hazard? eyeball hazard? What is a good way to measure this?)
  • Interrupted light: At some point, a person will look straight at the laser. They have a receiver that will shut off the laser if there are ANY interruptions, but what if it isn't fast enough? What is "Safe exposure"? How to measure?
  • Glasses: If I walk through the beam, and it hits the inside of my glasses, and it partially reflects, how can I measure if it was a safe level (<1mW) of exposure?
  • Eyeball: If I walk perpendicular to the beam, and the beam catches the anterior chamber of my eye (or an eyelash), will it cause damage?
At the end of the day, I'm not sure that a class 4 laser will ever be safe, but if the pulses are short enough, and the feedback loop is quick enough, it might be possible. Thus, I need to create a test setup that can prove it is not safe, and I would appreciate your help.

Thank you for your help, -EngineerVsMBA
 
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WizardG

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Video camera that can image IR light to look for reflections and a power meter to quantify the reflected power as a start?
 
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We can't help much until you describe what the product is and how and where it will be used.
 
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EngineerVsMBA

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Simply creating a wide beam would solve the problem. Do you have specs for this ir laser?
I do not. We are currently in a CDA/NDA/IP related contract negotiation. Their receiver seems to be about the size of a US quarter (.5", or 12mm wide"). While legal works through the contract, I'm trying to create the test plan.
 

Encap

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You need to hire a qualified certified Laser Safety Officer----and probably a Laser Testing firm. If you manufacture a product or a component that incorporates a laser, US Federal Law requires testing and classification of your product to US FDA 21CFR. Before you can legally introduce your product into US commerce, a Product Report detailing compliance with 21CFR requirements is required be filed.

You alone testing will be meaningless as you know nothing about lasers and whatever you come up with will not conform to the requirements of laser testing---maybe contact -- http://www.laserproductsafety.com/

US FDA will never allow it to be sold in the USA unless it meets all of their requirements including safety.
Talk to them about it.
It is not a very bright idea to begin with for several reasons.
That company has been peddling that idea for a long time. It died several years ago except for with "investors"
Nobody wants the cost or the risks.
At this point all it is a money scheme, is a pitch to to get "investment" dollars from people who don't know any better and never have a commercially viable product.
 
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The fact that it has an open air beam over 5mw, visible or not, and needs a safety system is a problem in a consumer environment.
 
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I can't think of a way to PROVE safety for such a scenario. Some unknown and unforseen problem might inhibit any safety device.

Looking at the application made me wonder how a directed light ray might find the intendet target and keeps locked at it. I remember an article several years ago about some nanotechnology flat retroreflector. A mirror that reflects the beam excactly back to its origin on a quantum level over a broad range of angles and in the same phase.

I do not have the article handy. It was published in a reputed paper not some kind of ScienceFiction, but it was certainly some years (or even decades) ago, not this publication from 2017. They called the surface "time reversal mirror" as the light beam mathematically was undetermined about the "direction"

The receiver might be an application of this concept. IF this is the case, the "Laser" is triggered by an initial ordinary flash that reflects back to the origin, starting the resonance in the proper direction. Such a resonance would immediately and automatically collapse, when something enters the beam, as the air space IS the laser cavity. So there is no thing like looking "into the beam", unless your retina reflects enough light to initiate a resonance. If I remember correctly they had a proof of concept with a metal kitchen spatula that triggered a lasing resonance between a specular reflection and the "mirror".

Reflection of the beam in directions other straigth back should not be a problem in this scenario either, as all the magic is done in the retroreflected beam only.

This is certainly pure speculation. Someone would have to take the device apart.

What you have to do other than measuring the power is, determine the wavelength.

Potential damage greatly varies with the wavelength. Eye damage is a problem when the wavelength is focused by the cornea and lens and may pass the vitreus. Far IR radiation will not pass cornea and you would need really high power to produce any damage. The beam will at least not get focused to the retina, you would "only" face thermal stress to the cornea.

Even if the laser is in the 1W range, you probably will not have severe fire hazard. Not more than other electric devices with a few Watts of energy consumption.

If I would have to mesure the stray light, I would start with some IR sensitive camera, taking images from every direction. I would try to get an image of the beam, maybe with a transparent glass that is brought into the beam. Transparent enough to be "invisible" to the feedback device but may get some light out of it to be measured. This way you could both check the power and the conditions that would trigger the shutoff.

Anyway, I'm not convinced the device really works as advertized, but I often get surprised.
 
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We have seen this before now. It is not a very good way to charge a phone battery, or any battery for that matter. You will need to get enough power focused on the light receiver, plus you will need enough efficiency to convert this to usable power for the battery. Try doing this with a 1 watt laser aimed at your receiver and see how long it takes to convert laser energy into electrical energy. It is not nearly as easy as it sounds. Add this to the safety concerns and you will begin to see why this has not taken off before.
 




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