Laserium used solenoids. There have been pictures on here before of Laserium's scan glass system, and the front side is in the documentary. It had a 1/8 steel rod supported at each end with bearings that passed from the front on the head to the back side. There were 3 nested brass tubes riding coax around the steel rod. In the back of the projector were three cylindrical solenoids that attached to a lever clamped on each of the brass tubes for mechanical advantage. There was a another aluminum link that attached the lever and the solenoid. the link allowed for the mix of straight line movement of the solenoid and the rotational motion of the lever. On the scan through side there were originally brackets clamped on the brass tubes and the scan glasses were screwed onto the brackets. When we started doing different shows in the same night/week we went to a clever spring loaded quick release scan glass holder.
AVI used pneumatic actuators
"There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso