All color tubes were not called "banana tubes."
There was a type of experimental color picture tube, developed by the vacuum-tube maker, Mullard of England, specifically called the Banana Tube.
This tube resembled an elongated wine bottle, with a single electron gun in the neck and a line going down the side of the bottle which was a single triad of three phosphor stripes, red, green and blue.
The electron beam was made to scan the triad, switching colors at a very high rate, similar to the method used in the Lawrence Chromatron, over and over, scanning out each TV line on the single triad.
The tube was in turn mounted in a rotating drum with a specially shaped curved mirror behind it, so that the glowing single stripe was made to scan the image vertically by the drum's mechanical rotation. The horizontal scanning was, of course, done by the electron beam.
Evidently this tube was developed at the time that the BBC was experimenting with a 405-line version of the NTSC system, sometime in the 1950s and early 60s. None of this came to fruition of course and color in England waited until 1967, when 625-line PAL broadcasts on UHF were initiated.
By this time the shadow-mask tube was well entrenched, sporting improvements like rectangular shapes, rare-earth phosphors and possibly by that time, in-line guns.
Other developments like plumbicon color cameras and high-band videotape recording also insured that when the Europeans finally got color television, they got a well advanced system and never had to face the years of slow growth and technological problems that we had in the U.S.
|
