Flying spot scanner

Image of Scanned Spot Generates Current in Detector 

Obviously, a fast-decay phosphor is mandatory for this application. Decay times of nano-seconds, i.e.- 10 second, are required for this scanning mode to achieve sufficient detail since the film is moving at the rate of 30 frames per second. The phosphors used for flying spot scanners include  

One of these phosphors, YP04 Ce, was developed by the author. Whether it was ever used in the flying spot application remains unknown. Perhaps, the fastest decay phosphor known to date is Lu2Si05 Ce. whose decay to 10% is 1.5 ns. 

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P-15 ZnO Zn ZnO (reducing atmosphere) Used originally in a flying spot scanner is applicable for any CRT requiring a highly visible screen and a fast decay. Green-emitting phosphor (515 nm). 

Deep blue-emitting (centered at 415 nm) phosphor screen used wherever a very fast decay is needed, such as flying spot scanners... 

When fired in a reducing atmosphere, Y3A15Oi2 exhibits a pronounced afterglow due to traps formed by oxygen vacancies [5.356]. Subsequent annealing in air diminishes this effect and leads to decay times of 200 300 ns therefore, Y3Al5Ol2 Ce3+ is used in flying-spot scanner tubes. The emission maximum is at 550 nm. This phosphor is classified under P46 (TEPAC) and KG (WTDS) (see Section 5.5.4.3). 

SrGa2S4 Ce3 +, Na+ with 4 mol% cerium (Amax = 455 nm, rj — 5.0%) and SrGa2 S4 Pb2+ with 8 mol% lead (2max = 595 nm, rj = 4.6%) are used in flying-spot scanner tubes because of their short decay times (7o/100) of 1.55 ps and 1.24 ps, respectively. Their low ageing upon electron beam bombardment is also noteworthy. Because of the relatively broad emission bands, a blend of 15 wt% SrGa2S4 Ce3+,... 

Ce" yttrium aluminum garnet Y,A1,0 550 yellow flying spot scanners... 

Electrochrome display = 1 Radar display =16 Flying spot scanner = 8 Storage monitor = 1 Light pen on display = 1... 

The other application is the flying-spot scanner. In this set up the information of slides or film can be transfonned into electric signals. The election beam excites a phosphor with short decay time. The luminescence signal scans the object point by point and the transmitted radiation is detected with a photomultiplyer. To reduce blurring of the signal, the decay time of the phosphor should be of the order of magnitude of the time the electron beam scans a picture element ( 50 ns). 

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