MPE measurements

[sbk]

Will a simple Coherent Lasercheck work to mesure MPE, if I measure a static CW beam?

Aperture diameter is 8mm, and measureable power swing between 0.5 µW and 1W...

[mccarrot]

Not sure...

But the lasercheck can only measure one wavelength so it's not usable for RGB laser MPE calculations. (or you must measure every color independent and do more math)

I also heard the laser check is not that accurate.

Also not sure what the safety officer will say if you tell him you did measurements with a pen

[sk_1810]

I suppose it would do as a low-budget solution for 532nm laser shows?

[mccarrot]

I think Laserben still got one Fieldmax TOP for sale for 400USD in the buy/sale topic

[norty303]

You might want to check out this software (free for 532nm) for calculating your MPE once you know the output power. It's been pretty useful in the last couple of months.

http://www.lasersafepc.com/B_Home.htm

[sk_1810]

Norty, thanks! Very useful piece of software!

Tell me, which "Exposure Time Frame" parameter you use for beam show evaluation?

[mccarrot]

The software is useless if you don't know what laser power you have.

a 2 W laser can give 2,5W. The 2 mRad could be 1 mRad etc.

You cannot trust on (Chinese) specifications so you MUST measure the power.

And with the simplified approach we don't need the software anymore as long as we keep the beams moving

[sk_1810]

I know...

I'm playing around with the software using approximate values.

However, I have measured specs for one 2W 532nm unit, the only thing that remains is the Exposure Time Frame". I think it should be below 0.5 seconds, but I'm not sure, so it is better to ask...

[sbk]

LaserCheck is accurate at +-5%, which remains acceptable...

Also an affordable way with the Lasercheck would be to know the exact power of each laser (measured at the aperture of the projector, after optics), add the power of all lasers inside the projector, then precisely measure the divergence of the lasers and pick the smallest one (if you will not bother to do the maths separately for each laser), and do the irradiance calculations at the closest point of audience access.

For sure it will be theorical values only and a real measure would still be better, but that should not be so far from reality. And you can still add a security margin to be sure...

[mccarrot]

Sure but if you are planning to do a show every few weeks it's a lot of work.