Quote:
Originally Posted by Telecolor 3007
... When the qualty of color pictures tubes imporved?
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You can find previous discussions on this forum.
http://www.audiokarma.org/forums/sho...d.php?t=105491
Essentially all the improvements in color picture tubes involved increased brightness and contrast, rather than precise NTSC color characteristics. There were many incremental improvements over the years.
The major stages were probably:
1)experimental phosphors requiring a colored filter over the screen
2) NTSC phosphors used in the 15GP22 and early 21AXP22
3) All-sulphide phosphors
4) Vanadate red
5) yttrium oxide (europium) red
6) zinc cadmium sulfide green (later reversed to remove cadmium from the process due to environmental concerns)
Note that the zinc sulphide blue, zinc sulphide green, europium red combination is what has become standardized (with slightly varying specifications) for PAL, HDTV, and the sRGB standard for digital still cameras.
(following not necessarily in order)
7) rectangular tubes with wider deflection angles
8) black matrix / negative guardband screen
9) grill mask (Trinitron)
10) in-line-gun shadow mask, self-converging deflection
11) darker faceplates
12) improvements to shadow mask thermal stability (materials and/or mounting)
13) for CRT projection sets: various green phosphor formulations including rare earth components to reduce current saturation; liquid cooling / optical coupling; low-flare optics
Probably other things I'm forgetting.