Over the weekend I spent time making fine adjustments to an LOC 826 diode module to allow all the diodes to fit the scanner mirrors without any telescope and I made it. The far field combined beam was slightly less than 1 cm. at 12M. Great! "The projection should now sparkle". It certainly wasn't worse, maybe a little better, but not much. So I set up a test pattern, Slightly misaligned the lasers to produce three single color grids and measured the X and Y line widths. The blue (445) which has three X the divergence in the worst axis ( at 1.75 mrad) was wider at aprox. 3.0 mrad and in its best axis ( at 0.5 mrad) was almost 2.0 mrad. Both the green and the newly tuned red at 0.8 mrad also produced 2.0 mrad lines. I am using an Eye Magic scanner with the 9.5mm aperture mirrors and although shows are typically preformed 18-20 K speeds, even at 10 K there was no improvement in the line widths. An additional fact is when the lasers and scanner are "disabled" the faint residual blue beam is double the diameter of the intercepted static beam.
I also notice that when the static beams are perfectly aligned and then put through the scanner they always need a small adjustment to overlap on the test patterns and when rechecked in static mode they are always slightly misaligned.
Is this due to jitter or position inaccuracy? Is this typical of all of these moderately priced scanners? Can anything be done to reduce or eliminate this? Or are we wasting time trying to reduce divergence below 1-2 mrad because it will be overwhelmed by scanner limitations?