Hi Devmonkey

Your comment.....
"or the laser line is using a diffraction pattern rather than a cylindrical lens."

Yes I think there is a problem with the laser source.

Without the lens the graph is far worse with multiple peaks. Upon opening the case there is a shaped plastic stepped prism that limits the beam to 90 degrees of coverage. the step is in the middle of the laser. (There are actually 2 similar laser sources in the unit) both are the same. it is not a tubular lens.

I will have to source a good quality line laser. not sure where yet?

The camera sensor appears to be closer to 3.5mm wide including the border so I guess the active area to be about 3mm wide. Its a fairly old unit but it works well.

Regards
John