I know most folks are probably focusing on historic standards like the 30 and 32 line screens, but I'm wondering about how far the mechanical display technology could be pushed based on physical limitations.
According to my calculations, I could get a 3.5 inch wide display from a 2ft disc. This is with the screen at the top of the disc rather than the side so scan lines are going horizontally across the image and a landscape oriented image of 160x90. Because our eyes are side by side so horizontal resolution matters more, and 160x90 would be a convenient multiple of the 16x9 standard. This would be accomplished by an overlapping spiral of dots on the Nipkow disc with a second spinning disc as a mask to occlude the ones not being scanned for that rotation.
It seems like the main limitation is how fast an LED light source can flash per second. Does anyone have an idea of the refresh rate they're capable of? A simple on/off wouldn't be so difficult, but pulse width modulation to vary the brightness doesn't seem like it would be practical in this application because of the speed?