A new guy!

[buffo]

Hi Giovanni;

Ok - that second picture shows different dichros than you had in your first projector. (The one's in your first projector looked square...) The new ones should work just fine - especially with those nice mounts from LaserWave.

Marc has a good point about putting the green laser at the back, then mixing in red, and finally mixing in blue right before the scanners. Blue photons are the most expensive, so you want to conserve them!

As for using a dichro instead of a mirror to reflect the red beam (or the green one once you re-arrange the lasers), you'll find that a dichro will often perform just as well as a mirror, and in some cases a dichro is *better* than a mirror. Test it both ways to be sure.

And as an aside, here's link to a source for *cheap* first-surface, 1 inch diameter broadband mirrors that will fit nicely into those mounts. (They only cost $12 each!)

If you mount everything to the baseplate, remember that you will need some way to adjust the height of each laser so that you can get your near-field alignment adjusted correctly. Some people use shims under the laser to adjust the height. This requires very accurate measurements beforehand so that you can get the shims machined to the precise thickness needed.

Another method is to actually mount each laser on it's own plate that is suspended above the main plate by 4 threaded rods and a set of nuts and lock-washers on top and bottom. By moving the nuts up or down on the threaded rod, you can change the height of the "floating" table for each laser. (This is the method that both Marc and I have used.)

In either case, once you have the near-field alignment correct, you can then use the adjustment on the dichro mounts to get the far-field alignment dialed in.

A third method is to hard-mount each laser to the baseplate no matter what the beam height is, and then use *two* bounces to adjust the red and blue beams to match the green one. In this configuration, the first bounce is off a mirror, and the second one is off the dichro face. It makes your layout a good bit larger, and you'll need two extra mounts and two extra mirrors, but the alignment of such a layout is *very* easy. You use the mount on the bounce mirror to get the near-field alignment perfect, and then the mount on the dichro to dial in the far-field alignment.

Not sure if you'll have room in your current projector housing for option #3, but keep it in mind for future projects!

Adam

[h2so4]

Thanks for the very accurate advice, it will be very useful! About the case, I am going to throw that crap out of the window!!! I think I will modify a small computer case or I will think about something else...thank you very much for the link to the mirror - you saved me a lot of money as I wouldn't need a new mount for that one! At the moment I think I will stick to option 2, as it seems the most affordable, but I will also consider option 3, because - as you pointed out - it makes alignment quite easy...
Again, thanks for the advice!!!