Rgb spatial filter. One blade pinhole method

[planters]

Take a look at the round SS shim stock on this page. Several thicknesses are available.
http://www.mcmaster.com/#shim-stock/=twnvc7

[tribble]

Take a look at the round SS shim stock on this page. Several thicknesses are available.
http://www.mcmaster.com/#shim-stock/=twnvc7

I think for the price I would just get a roll and some scissors and hand the rest out at a LEM.

[masterpj]

This is a really interesting method!
Sadly thorlabs aren't present here and sending those lenses over are pricey... however I am very interested in this method!

Thanks for sharing your findings! Really clever.

[jors]

Many thanks! maybe Edmund?
http://www.edmundoptics.com/optics/o...ic-lenses/2684

[jors]

Great discovery Eric

[masterpj]

Many thanks! maybe Edmund?
http://www.edmundoptics.com/optics/o...ic-lenses/2684

Thanks! Think it will still be really expensive since a shipping estimate has to be made seperately to ship such a thing as this to the Netherlands.
I don't know which one I would exactly need either.. there is a lot of choice @.@

Do you only use these lenses for the burning process and then place the razor into the beam path?
How do you know how far to place them once inside the projector as the beam expands from within the projector.

[jors]

I see...
Well, the choice of lens depends on the room you have for the spatial filter and the magnification you want to achieve, you know.
Longer filter... easier to find focus

[planters]

I have a thought here. The primary reason I originally designed the spatial filter with adjustable razor blades was to compensate for variations in beam position and the uncertainty of the best focus diameter. If however, there is a consensus as to the best converging lens FL (say 50mm, just to pick a figure) then there will actually be only a couple of best diameters for most projectors. Someone with a decent projector with sufficient power could burn a few dozen of these in an hour as long as the raw material as in discs or squares or strips was available. Just send him a self addressed envelope with a couple of dollars and your set. Order the "designated FL lens (pair-remember) from your favorite source, place the pin hole onto a block with an oversize horizontal through hole, apply some epoxy to the base of the block and to the pin hole and fine adjust the position to maximize throughput and beam quality while the epoxy cures and your done.

[logsquared]

The calculators on this page may be useful to get an idea of pinhole size with different lens FL's input dia. etc: http://www.buildlog.net/cnc_laser/laser_calcs.htm

[planters]

That's a nice calculator. Thanks.