>> You'd probably know, then - what's the fastest way to deflect a >> laser beam? In particular, I'm wondering how practical it might be >> to take a laser and turn it into a vector display on a handy blank >> wall [...] > What bandwidth (deflection rate) do you need? Full scale in a > microsecond? In 10 microseconds?
Well, if it takes longer than 100ms to replot the display, it will flicker visibly, and the more under 100ms the better. In that time I'd like to draw at least a couple hundred lines, though most of them will be short (line length maybe 1-15% of corner-to-corner distance). What kind of radians/second deflection rates this means depends on how far from the wall you put the projector. But, in terms of the bandwidth on the X and Y axis signals? If we say 200 lines at 25 ms replot (I get 20ms frame rate out of the cg6 for displays significantly more complex than that - ie, with the cg6 the actual limitation is the video signal vertical frequency), that's 125us/line. Turning sharp corners is the hard part with mechanical deflectors like mirrors, as it means very high acceleration of the mechanical parts. I haven't done the math to be sure, but, until/unless taught otherwise by testing, I'd feel dubious about clipping the X and Y signal bandwidths at anything lower than ~1MHz. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTML mo...@rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B