beam artefacts...

[csg]

Over the last few months i have been building my first 2 RGB projectors using

Edison 680mw 637nM modules
Edison 1500mw 450nM modules
CNI 1000mw 532nM DPSS modules
edmund kinematic dichro mounts
JM raytrack scanners with scanfail etc
traco medical grade PSU's

I have 20 odd years of electro-mechanical engineering experience behind me, so the actual build and construction has been fairly straight forward and overall i am very satisfied with the results, with the laser heads having been used on multiple shows and productions over the past few months with very few issues.

i do have a couple of questions though which im hoping some more experienced members may be able to help with.

the main question is illustrated in the picture below



you can see on some of the beams ( to the eye it is visible on all to a greater or lesser extent) a dimmer fringe of output each side of the main beam. if i change the scanning speed, the main beam changes position within the fringe. This pic was taken at 25K, this speed seeming to centralise the beam within the fringe.

is there anything that can be done to clean this up - as to my mind it is a waste of power that is reducing the visual output, however marginally.

control is via quickshow and a FB3.

My second question is regarding brass flex mounts - i started out with these a my cases had been designed with them in mind, but found them to require constant tweaking to maintain good alignment, with the standard pitch screw threads providing somewhat course adjustment. After a couple of months, i replaced them with kinematic mounts from Edmund, and since, things have settled down considerably with the laser requiring far less adjustment. Is this something other members have experienced with the brass flex type mounts?

thanks in advance for your help!

[polishedball]

If those are suppose to be static beams. I am betting you have a finger print or something on am optic possibly a reflection back onto an optic. Is your case powder coated internally black as well as mounts for the optics.

Over the last few months i have been building my first 2 RGB projectors using

Edison 680mw 637nM modules
Edison 1500mw 450nM modules
CNI 1000mw 532nM DPSS modules
edmund kinematic dichro mounts
JM raytrack scanners with scanfail etc
traco medical grade PSU's

I have 20 odd years of electro-mechanical engineering experience behind me, so the actual build and construction has been fairly straight forward and overall i am very satisfied with the results, with the laser heads having been used on multiple shows and productions over the past few months with very few issues.

i do have a couple of questions though which im hoping some more experienced members may be able to help with.

the main question is illustrated in the picture below



you can see on some of the beams ( to the eye it is visible on all to a greater or lesser extent) a dimmer fringe of output each side of the main beam. if i change the scanning speed, the main beam changes position within the fringe. This pic was taken at 25K, this speed seeming to centralise the beam within the fringe.

is there anything that can be done to clean this up - as to my mind it is a waste of power that is reducing the visual output, however marginally.

control is via quickshow and a FB3.

My second question is regarding brass flex mounts - i started out with these a my cases had been designed with them in mind, but found them to require constant tweaking to maintain good alignment, with the standard pitch screw threads providing somewhat course adjustment. After a couple of months, i replaced them with kinematic mounts from Edmund, and since, things have settled down considerably with the laser requiring far less adjustment. Is this something other members have experienced with the brass flex type mounts?

thanks in advance for your help!

[csg]

the optics were clean when that picture was taken - and the projectors were not producing static beams in that picture ( that cue is a slowly rotating cone). I am not aware of any internal reflections ir stray radiation hitting any internal surfaces - all beams fit their mirrors / filters and scanners very well.

could it be a switching speed issue with the FB3?

[Insanity]

Try adjusting blanking shift in your software, that might help clear some of it up...

[csg]

thanks, will do - but i seem to remember that this changed the position of the bright beam within the fringe area in a similar way to changing the scanning speed. I will try this again tomorrow.

[Eidetic]

Could you be hitting an edge of a mirror while scanning it, causing scatter?

[dnar]

Looks like non optimal blanking shift to me. Post a pic of static beams on the wall.

[loopee]

Also make sure you're reflecting the beams off the correct side (i.e. front surface) of the mirrors for both the flex mounts and scanners

[norty303]

Chris, it is probably caused by the lasers switching on just prior to the scanners being in position and switching off just after they leave the position. The fact that changing the blanking shift moves the beam within the fringe seems to bear this out.
A colour correction board would sort this out as you could delay the turn on time.
I suspect a better scanner would also sort it, in as much as it would be in position faster when the laser turns on, rather than still moving to the position.
It could also be a less than well optimised frame whereby even with the best scanners in the world you might still see some smearing. I wonder if adding some blanked points before each point might help

[csg]

well, i had a little time this afternoon to check through some of the suggestions above.

Optically, everything is correct in terms of mirror surfaces, dichro surfaces and beam positioning on the scanner mirrors etc. I also had another play with the blanking shift and scan speed, but to no avail.

In the end, i decided to use the quick shape editor to replicate one of the frames which was giving me issues - a simple green fan. On the frame i made there is no fringing beside the bright beam, on the existing frame there is. It seems like a large proportion of the stock beam show frames on my copy of quickshow exibit the same issue, so it seems that i have a lot of work to do re-building my frames!

thanks all for your help.