Author Topic: Are the green glasses from Chinese kits safe?  (Read 7939 times)

Stonemull

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Re: Are the green glasses from Chinese kits safe?
« Reply #60 on: April 11, 2017, 11:56:15 AM »
Not wanting to flog a dead horse but I think I have some fairly conclusive evidence here of what these goggles are capable of.
Browsing around for OD4 goggles on aliexpress has made me realise the chinese have a different interpretation of 'OD' than everyone else.

Below is the description from one seller and what appear to be the green goggles we have been sent.
The interesting facts are the description OD4+ and the Transmission value quoted 15% or 0.15

(on ipad in aliexpress app, links are nowhere to be found, search for 'OD4 445nm' to locate our green goggles and some ugly as he** red ones with equally bad ratings)

The relationship should be .. http://www.wavelength-tech.com/Technical/Technical17.jsp

-log(0.15) = 0.82


Quote
Name: 405nm 445nm 450nm Blue 808NM 980NM IR Laser Protection Glasses Goggles OD4+

Specifications
Protection Features: All-round absorption
Protection Wavelength: 200-540nm
Visible Light Transmittance: 60%
Optical Density: OD 4+
T(405nm-450nm)=15%
Size:145x110x45mm
Suitable For: Quadruple-frequency Nd: YAG laser / excimer laser He-cd / YAG laser / semiconductor laser

So basically these green goggles are not even OD1 at 445nm, actually around OD0.8 .. so a 2500mW laser becomes a 375mW laser while wearing these 'safety' goggles.

Another seller of some red goggles had this to say in description, quoted a few relevant parts..

Quote

 
Features
1. Protection wavelength range: 400nm- 600nm
2. Protection features: all-round absorption
3. Visible light transmittance: >55%
4. Optical Density: > 5.0, (OD +4, OD +5)
5. Attenuation: (10-6
Package:
1x 400-600nm Green Laser Protection Goggles Safety Glasses w/ box
 

2. for the T: some people do not know what the T mean, T here means transparency. for a special wavelength goggles, a T=30% means there are 30% laser can pass through. for a full wavelength goggles, T here means an average level. as you can see in the picture, when you use a 405nm laser for the goggles, there are about 30% can pass through. if you use a red/green laser, there is about 50% pass through. if we use a 1064nm on the goggles, it is about 20%. so that we get an average value for T=30%.
a customer of us said, a laser goggles should be T=0.01. if T here is 0.01, how you can see the laser beam path? for T=0.01, we have IPL goggles for patient: .com/itm/Eyepatch-Glasses-Laser-Light-Protection-Safety-Goggles-IPL-Beauty-Clinic-Patient-/111003193327?pt=LH_DefaultDomain_0&hash=item19d84e4fef. here T=about 1-2%. but this kind of goggles will block all laser light. you cannot see anything if you wear it.


So someow they are interpreting OD4 as .. well, just a number to be made up at will. They do seem to understand transmission, or not, they probably would not quote if they knew you can calculate true OD from it.

So basically WHILE WEARING these green safety glasses, you can consider you now have a class 3B laser at work while wearing NO PROTECTION.
Sorry for caps but I want to make sure it is understood.


Class 3B laser safety http://www.lasersafetyfacts.com/3B/

Always remember, that is while wearing the green goggles..
« Last Edit: April 11, 2017, 11:59:13 AM by Stonemull »
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ThothLoki

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Re: Are the green glasses from Chinese kits safe?
« Reply #61 on: April 11, 2017, 01:13:58 PM »
HERE HERE stonemull!!!

You said it a lot better than me just putting them under the laser and recording what happens.

Sorry, not going to throw my $50 pair under the laser "to see what happens" plastic is still plastic after all.
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Klaus

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Re: Are the green glasses from Chinese kits safe?
« Reply #62 on: April 15, 2017, 03:23:48 PM »
I was suspicious of the green "laser safety" goggles right from the start. Looking at the burning spot of a 445 nm / 2500 mW laser I could still see a very bright spot blinding me enough so as to look at it for for fractions of second only.
I found some excellent goggles here: https://www.augenlichtschutz.de/produkt/over-shield-red-xd-breitsicht-schutzbrille, they are orange and filter the blue totally. All you will see is the white and reddish light produced by the burning material. Might almost be too little to see for some purposes, but in terms of eye protection they are perfect. Look at the transmission curve (see below).
Has anyone seen a comparable transmission curve of the standard Chinese green goggles? Would interest me highly.
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Stonemull

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Re: Are the green glasses from Chinese kits safe?
« Reply #63 on: April 16, 2017, 12:25:04 AM »
I was suspicious of the green "laser safety" goggles right from the start. Looking at the burning spot of a 445 nm / 2500 mW laser I could still see a very bright spot blinding me enough so as to look at it for for fractions of second only.
I found some excellent goggles here: https://www.augenlichtschutz.de/produkt/over-shield-red-xd-breitsicht-schutzbrille, they are orange and filter the blue totally. All you will see is the white and reddish light produced by the burning material. Might almost be too little to see for some purposes, but in terms of eye protection they are perfect. Look at the transmission curve (see below).
Has anyone seen a comparable transmission curve of the standard Chinese green goggles? Would interest me highly.

Not totally, you still looking at 1% or more at 542nm, which is not yet OD2, 2 pairs of these and you are cooking. You would need full exposure to a reflection to take damage, a scattered reflection is probably safe-ish.
I am still looking for a cheap Od3+ .. this 545nm region is not well covered it seems.
« Last Edit: April 16, 2017, 12:29:04 AM by Stonemull »
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Klaus

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Re: Are the green glasses from Chinese kits safe?
« Reply #64 on: April 16, 2017, 05:45:50 AM »
Yes, but aren't most of these small China lasers 405 or 445 nm? For these wavelengths those orange goggles should be perfect.
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Stonemull

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Re: Are the green glasses from Chinese kits safe?
« Reply #65 on: April 16, 2017, 07:50:29 AM »
oops, yeh, 445nm though I did see a german website that accurately measured them at 442nm.

I have 545 stuck in my head ever now and then.
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Tom

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Re: Are the green glasses from Chinese kits safe?
« Reply #66 on: August 28, 2017, 12:57:23 PM »
Has anyone come up with a pair of good quality goggles that fit over eyeglasses for under $40?

Klaus

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Re: Are the green glasses from Chinese kits safe?
« Reply #67 on: August 28, 2017, 01:26:49 PM »
Once more: green goggles are not safe for UV/violet lasers.
To block blue and the UV-near violet, you need orange goggles.
Here you get a pair that costs below EUR 16 and are safe for blue and UV (you can download a transmission curve) and they fit over glasses:
  https://www.augenlichtschutz.de/produkt/over-shield-red-xd-breitsicht-schutzbrille/
The site is in German, but you can write to them in English.
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Tom

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Re: Are the green glasses from Chinese kits safe?
« Reply #68 on: August 28, 2017, 01:50:48 PM »
Once more: green goggles are not safe for UV/violet lasers.
To block blue and the UV-near violet, you need orange goggles.
Here you get a pair that costs below EUR 16 and are safe for blue and UV (you can download a transmission curve) and they fit over glasses:
  https://www.augenlichtschutz.de/produkt/over-shield-red-xd-breitsicht-schutzbrille/
The site is in German, but you can write to them in English.

Yes, I understand that we need to be wearing the orange goggles. My eyes have always bothered me when I'm working with the laser with the green goggles. So I want to order something with more protection. Is there a USA distributor for these?

Klaus

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Re: Are the green glasses from Chinese kits safe?
« Reply #69 on: August 28, 2017, 02:35:45 PM »
Sorry, I just know this German distributor (I live in Germany).
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ThothLoki

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Re: Are the green glasses from Chinese kits safe?
« Reply #70 on: August 28, 2017, 03:19:59 PM »
Sorry, I just know this German distributor (I live in Germany).

They are not under $40 ($49.99), but I bought two sets of these and have never had the scratchy eye problem like I used to with the Green ones
http://www.survivallaser.com/Eagle_Pair__190-540nm_OD6_Slip_Over_Laser_Safety_Goggles/p556088_3346945.aspx
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Stonemull

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Re: Are the green glasses from Chinese kits safe?
« Reply #71 on: August 30, 2017, 07:50:33 AM »
I am very happy with the $3 red ones I got from china, just ordered 2 more pairs as I am also using them with my plasma cutter in the shed and keep forgetting to bring them back inside.
link is around this area of the forum somewhere.


edit.. found em in my banggood orders.

PC Material Adjustable Laser Pointer Eyes Protective Glasses
https://banggood.app.link/EvneJqje2F
« Last Edit: August 30, 2017, 07:58:41 AM by Stonemull »
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