LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))

Paul Koning paulkoning at
Wed Jul 20 08:08:18 CDT 2016

> On Jul 19, 2016, at 4:58 PM, Wayne Sudol <wsudol at> wrote:
> Laser technology to draw things like this is used in photo typesetters. A
> laser beam is focused onto a thin (about 1/2" thick)  many sided (about 8
> sides i think) spinning mirror. Each facet of the mirror is cut differently
> to deflict the beam up, down or center it on a sheet of moving paper or a
> plate of sensitized aluminum. 

Depending on the typesetter, the spinning mirror might just be horizontal deflection, with vertical positioning provided by the film transport motor.  But in any case, those are raster scan systems.  It's very easy to scan a light beam in a regular pattern at high speed, with schemes like this.

DLP (micro-mirror chips) are also raster systems.  


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