How to stack laser projectors to increase the laser output brightness and reduce flickering

In this video tutorial John from Laser Ninja Productions shows how to create one laser output image from several stacked laser projectors.  The tutorial video has been recorded at the Comic Con 2017 at the Alamo City. The intention was to run a laser marquee for the people coming in to the event.
John was in a kind of unique situation as he just sold off all of his really high-powered laser light projectors, so for the laser marquee, he needed to bring out a couple, two and a half watt lasers in the mid-power range, that he double stacked and aligned.
By this he got more brightness than he would with just a single laser light projector.

Stacking laser projectors similar to DLP projectors

He learned this kind of trick way back in the days, when he used to work with CRT projectors where he also double stacked those. Something’s still useful for like DLP projectors or led projector is a crosshatch pattern and compute geometric correction.

Professional tools in Pangolin laser show software

All of that is available in the Pangolin laser show software solutions. So at first, he took a look at the projection zone configurationdialog inside of Pangolin Beyond.
Two zones need to be overlapping with each other. This has been acomplished with the alignment configuration or the alignment test pattern for both projection zones in the professional Pangolin BEYOND software.

Steps at a glance

1. Roughly align the basic laser output pattern on their center.
2. Basically align the four corners of the laser test pattern.
3. Fine tune the alignment by using the crosshatch pattern.

Beyond Projection Zone geometric adjustments in detail

Step 1 – Matching the center of both laser test patterns together

So in the first step, he aligned the centers of the two rectangles.
After setting the position, it was to adjust the relative size. The second scan zone needs to be slightly larger than the first one.
In the end, the centers came together. When there was only one center line, he needed to adjust the left and right.
For the first step it did not need to be perfect – it could be adjusted when fine tuning later, with the geometric correction with the crosshatch pattern.
But the center x and the numbers should be roughly centered.

Step 2 Align the laser test pattern corners

Next was to have the four corners match to the side.  Adjustment could be done with the mouse and more accurate with the keyboard arrows later.
It helped to eyeball it in with the mouse to get it roughly into the right position and then to walk it in with the keyboard. The idea was that the dots in the corners should line up as much as possible.

Step 3 Fine tuning with the crosshatch laser test pattern

Now after all four corners matched up, it was to change from the basic alignment to the crosshatch. There should be a crosshatch on all four corners.
Again the trick was to eyeball every corner, really focus on the area that he was working on, because when the corners came together, he saw it almost click with his eyes. There was a lot of flicker first and then all of a sudden the flickering did stop. So it will look fairly solid.
When all four corners really dialed in with the crosshatch pattern, he switched to the 3×3 pattern. And this gave him the chance to really adjust several new areas that weren’t in the pattern before. Center top, top center, left center, right center and lower center. This gave him a cross pattern that could be adjusted.
When he relaxed his eyes and he actually got both of both areas aligned correctly, he literally saw it just kind of pop and click into place.
Further more, he took a look at the 5 by 5 pattern, which gave him several new areas. If needed fine tuning can be continued with the 9 by 9 pattern.
The goal is that both projection zones actually overlap perfectly over each other. There should be no line doubling or anything like that.

See the whole video tutorial about Stacking laser projectors together and matching BEYOND projection zones here: