26-03-2017, 10:14 PM
These very early systems did a vertical raster, rather than horizontal. So the slow scan direction was horizontal.
There were all sorts of weird and wonderful systems pre CRT. The Eidophor projection TV (also used for cinema) used an electron beam to write a raster on a film of oil. The optical diffraction pattern from that was the projected image. Because of heating of the oil film the (concave) disc continuously rotated, and a doctor blade presented a uniform thickness of virgin oil film to the electron beam. They even had a rotating colour filter wheel synchronised to the scan to produce frame sequential colour.
Back in the mid 80's I developed a not dissimilar system for BAe https://www.flightglobal.com/FlightPDFAr...201593.PDF based on solid state scanning.
Astonishingly there are still one or two of them still in use, in spite of new generation technologies making the Microdome projectors essentially obsolete.
There were all sorts of weird and wonderful systems pre CRT. The Eidophor projection TV (also used for cinema) used an electron beam to write a raster on a film of oil. The optical diffraction pattern from that was the projected image. Because of heating of the oil film the (concave) disc continuously rotated, and a doctor blade presented a uniform thickness of virgin oil film to the electron beam. They even had a rotating colour filter wheel synchronised to the scan to produce frame sequential colour.
Back in the mid 80's I developed a not dissimilar system for BAe https://www.flightglobal.com/FlightPDFAr...201593.PDF based on solid state scanning.
Astonishingly there are still one or two of them still in use, in spite of new generation technologies making the Microdome projectors essentially obsolete.
