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FrozenGate by Avery

UV Laser Safety Goggles Question

Laser Beam Wavelength .......... 405 nm
Exposure to Beam Time Frame .... 10 s
Laser Output Power ............. 400 mW
Axis 1 Laser Beam Diameter ..... 1 mm
Axis 2 Laser Beam Diameter ..... 1 mm
Axis 1 Beam Divergence ......... 0.5 mr
Axis 2 Beam Divergence ......... 0.5 mr
Laser to Target Distance ....... 0.1 m

Calculation Results:

Limiting M.P.E. ........ 100 J/m²
Accessible Emission .... 104 kJ/m²
M.P.E. Excess .......... 1040
Class 1 AEL Excess ..... 10300
N.O.H.D. ............... 450 m
Extended NOHD .......... 3.23 km
Nominal O.D. ........... 3 3.3
MPE Limit Aperture ..... 7 mm
ExNOHD Aperture ........ 50 mm
Test Class ............. 3B
Spot Major Axis ........ 1.05 mm
Spot Minor Axis ........ 1.05 mm
Beam Irradiance ........ 10.4 kW/m²
Radiant Exposure ....... 104 kJ/m²
EN207 L Number ........ DL5
Class Time Base ........ 100 s

So for this one also you would still be ok with D L5 @ 405nm
 





Laser Beam Wavelength .......... 532 nm
Exposure to Beam Time Frame .... 10 s
Laser Output Power ............. 150 mW
Axis 1 Laser Beam Diameter ..... 1 mm
Axis 2 Laser Beam Diameter ..... 1 mm
Axis 1 Beam Divergence ......... 0.5 mr
Axis 2 Beam Divergence ......... 0.5 mr
Laser to Target Distance ....... 0.1 m

Calculation Results:

Limiting M.P.E. ........ 10 W/m²
Accessible Emission .... 3.9 kW/m²
M.P.E. Excess .......... 390
Class 1 AEL Excess ..... 385
N.O.H.D. ............... 275 m
Extended NOHD .......... 1.975 km
Nominal O.D. ........... 2.6 2.9
MPE Limit Aperture ..... 7 mm
ExNOHD Aperture ........ 50 mm
Test Class ............. 3B
Spot Major Axis ........ 1.05 mm
Spot Minor Axis ........ 1.05 mm
Beam Irradiance ........ 3.9 kW/m²
Radiant Exposure ....... 39 kJ/m²
EN207 L Number ........ DL5
Class Time Base ........ 100 s

You would need eyewear with a rating of D L5 @ 532nm for laser pointers with these paramaters and <150mW
 
Hope this helps - let me know if you want me to run the calculations for any other lasers :-)
 
Alexizupinhea said:
I understand AndrewGW that there is a lot to take into account on laser safety glasses. However, I may not know everything about how they make them or test them, but the way I test them is by exposing it to a direct hit in the same spot for 2 (maybe 5, i don't remember) minutes to see how much is going through, and they held up fine for my 100mW+ greens and my 100mW+ Blu-rays. They were melting the glasses, but the glasses still blocked the whole time, and it didn't burn a hole through. And, they were only $8 shipped from China.
Click to expand...

I'm glad the eyewear held up under your test. Personally I wouldn't want to trust my eyes to $8 unrated eyewear... however if you are comfortable with your testing and your results all I can say is its your eyes :-)

Also probably a good idea if you are recommending this eyewear to anyone else that you give them a very clear warning that its their eyes and to use the eyewear at their own risk....
 
To summarise: for "our" typical lasers this means laser protection goggles with rating D L5 (EN 207).
 
For those typical lasers you mentioned, yes.

Just obviously make sure that the rating D L5 applies to the wavelength of the laser you are using ;)
 
Thanks for the valuable information.
I have a question about goggles themselves...
Are laser safety goggles meant to attenuate the beam primarily by reflection or absorption (or both)?

What kind of eyewear would you recommend for:
2.5W 808nm
~2.5mRad divergence
4mm x 6mm beam diameter (multimode diode) @ aperture
 
RA_pierce said:
Thanks for the valuable information.
I have a question about goggles themselves...
Are laser safety goggles meant to attenuate the beam primarily by reflection or absorption (or both)?

What kind of eyewear would you recommend for:
2.5W 808nm
~2.5mRad divergence
4mm x 6mm beam diameter (multimode diode) @ aperture
Click to expand...

There are different types of laser safety glasses. The most common are made of a polymer material impregnated with absorbing dye. This type of eyewear relies on absorbing the laser light.

There is also Laser Glass Technology (LGT) which can be absorbing glass and or glass with dielectric coatings (that reflect certain wavelengths). On top of this some glass eyewear has 'self-healing' plastic coatings also - however even with these the general rule is if the laser has any cracks, scratches, burn marks or takes a direct hit from a laser you should replace the eyewear.

The results of the calculations for your laser are below;

Laser Beam Wavelength .......... 808 nm
Exposure to Beam Time Frame .... 10 s
Laser Output Power ............. 2.5 W
Axis 1 Laser Beam Diameter ..... 4 mm
Axis 2 Laser Beam Diameter ..... 6 mm
Axis 1 Beam Divergence ......... 2.5 mr
Axis 2 Beam Divergence ......... 2.5 mr
Laser to Target Distance ....... 0.1 m

Calculation Results:

Limiting M.P.E. ........ 16.4 W/m²
Accessible Emission .... 65 kW/m²
M.P.E. Excess .......... 3950
Class 1 AEL Excess ..... 3900
N.O.H.D. ............... 174 m
Extended NOHD .......... 1.257 km
Nominal O.D. ........... 3.6 3.9
MPE Limit Aperture ..... 7 mm
ExNOHD Aperture ........ 50 mm
Test Class ............. 4
Spot Major Axis ........ 6.25 mm
Spot Minor Axis ........ 4.25 mm
Beam Irradiance ........ 65 kW/m²
Radiant Exposure ....... 650 kJ/m²
EN207 L Number ........ DL5
Class Time Base ........ 100 s
 
HI AndrewGW

What I need for a Safety Google for a 40 watts DPSS 808 nm Laser?

Thanks!
 
Assuming other parameters are similar to last 808nm request in this thread you would need eyewear with a rating of DL6 @ 808nm.

Input Parameters:
Laser Beam Wavelength .......... 808 nm
Exposure to Beam Time Frame .... 10 s
Laser Output Power ............. 40 W
Axis 1 Laser Beam Diameter ..... 4 mm
Axis 2 Laser Beam Diameter ..... 6 mm
Axis 1 Beam Divergence ......... 2.5 mr
Axis 2 Beam Divergence ......... 2.5 mr
Laser to Target Distance ....... 0.1 m

Calculation Results:
Limiting M.P.E. ........ 16.4 W/m²
Accessible Emission .... 1.04 MW/m²
M.P.E. Excess .......... 63200
Class 1 AEL Excess ..... 62400
N.O.H.D. ............... 703 m
Extended NOHD .......... 5.03 km
Nominal O.D. ........... 4.8 5.1
MPE Limit Aperture ..... 7 mm
ExNOHD Aperture ........ 50 mm
Test Class ............. 4
Spot Major Axis ........ 6.25 mm
Spot Minor Axis ........ 4.25 mm
Beam Irradiance ........ 1.04 MW/m²
Radiant Exposure ....... 10.4 MJ/m²
EN207 L Number ........ DL6
Class Time Base ........ 100 s
 
I wouldn't personally use those ones or recommend them.

In America they would be "acceptable" as their optical density is sufficient, however the optical density of the eyewear doesn't take into account the power density of the laser and although in theory would provide enough attenuation, in reality the eyewear can fail and your eyes could be damaged.

In Europe, Australia and other countries we use safety standards that take into consideration the ability of the eyewear to withstand a given power and or energy density.

The D L6 means you need eyewear with a rating for L6 @ 808nm for your cw laser (D = cw laser). I won't bore you with what power density the equates to, but the higher the L number the higher the energy density the eyewear can withstand before it fails.

What I would recommend is something like:
Glendale Laser Eyewear & Specialty Filters

The XC frame style of this eyewear has EN207 ratings of:
800-804nm DIR L4
>804-830nm DIR L6

or anything with the correct rating for your laser. The company I work for in Australia sells the glendale model mentioned above for ~A$290 ex freight, GST etc.

So depending on where you are based you should contact your local Glendale eyewear rep and ask for part number 31-80121.

There are many other companies that can supply eyewear, in this case this was the first part number I looked up in my database that had the required ratings.
 
Last edited:
Thanks!

I searched and searched on Glendale siet but I can't seem to find a distributor in Singapore.
Is there an online shop where I can order the eyewear?
 
No worries. Its good to see people actually interested in the appropriate eyewear and not just going for the cheapest eyewear they can find.

You can order the eyewear from a few different places.

Perhaps the most convenient solutions would be to buy them locally in Singapore from Sperian Singapore:
Sperian Protection Singapore
680A Jurong West Central 1 #17-40 641680 Singapore
+6 567 925 508
+6 563 993 150

If you want to buy the eyewear online you can get them from rockwell laser industries
Link: Rockwell Laser Industries: Laser Safety Eyewear - HT 800 Diode

Or through the company I work for I can offer you the eyewear for A$250 + GST + freight. but we don't have an online shop. send me a private message if you want to do this option.
 
Thanks for all the help and info.

I think this is the most important investment in any laser project.
I wouldn't sell my eyes for a million dollars; I would not compromise on right and proper eye protection!!
 
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