Author Topic: Laser power ?  (Read 3043 times)

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Offline Lasersmith

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Laser power ?
« on: December 24, 2009, 08:18:09 pm »
I am a new and just starting with Lasers,
 I am trying to under stand the need for power levels ? 50-400mw ?
I want to be able to do text and graphics in a dark room,
with a distance of about 40ft. I also want to be able to use this in a public place, is this possilbe with 5mw lasers red /green ? maybe RGB later ?

I would like to stay under the legal 5 mw limit in the US./Texas

thoughts  or suggestions ?
thanks, the new guy waiting ....for my 30k Galvos to arrive.

Offline James

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Re: Laser power ?
« Reply #1 on: December 24, 2009, 08:31:02 pm »
Welcome to the LaserBoy Forum!  ;D

Think of it like this....

If you point a laser toward a target 40 or 50 feet away, how bright is that spot?

Now imaging spreading that same amount of energy over a WAY larger area.

A Laser projector is very much like an oscilloscope. A single beam of energy is deflected left to right by one galvo and up and down by the other in exactly the same way an oscilloscope takes an X and a Y input.

At any instant in time, there is really only that one dot that you see when you point a laser at a target.

The reason you see solid lines is because of persistence of vision in the human eye.

If you point a 5mW laser into your new 30K scanners, you will see something. But it will be very dim and hard to see, even in a totally dark room.

Unfortunately, there is no way to make any kind of impressive, full color laser projector that would be automatically legal in the USA.

However it is possible to design a projector to meet certain standards and get a certification for it.

To give you an idea of power requirements, I have an old ion gas system with a HeNe and an Ar laser. I think my total white output power is probably between 20 and 40mW. That's just about enough to look OK in a totally dark room. I only shoot about 12 feet away and about a 5 foot square image. I can not feel the white spot on my skin.

With solid state diodes and other stuff the new kids are using these days, it is very possibly to build an inexpensive full color laser projector that can set fires at 40 or 50 feet.

Actually, you really do need this kind of power to be able to use it in large rooms and especially for aerial beam shows.

Don't kid yourself. Lasers above 5mW in power really are dangerous!

James.  :)
« Last Edit: December 24, 2009, 08:46:41 pm by James »
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