[opendtv] Re: New Chips Improve Color TV Dramatically
- From: jeroen.stessen@xxxxxxxxxxx
- To: opendtv@xxxxxxxxxxxxx
- Date: Thu, 24 Jun 2004 12:47:29 +0200
Hi,
John A. Limpert <jlimpert@xxxxxxx> asked:
> Has anyone ever made a picture tube with more than three primaries?
No... because that would not work with the principle of a shadow
mask tube. For N primaries the transmission of the mask is less
than 1/N. If you then subtract some landing reserve, soon you are
left with zero transmission. There have existed focussing mask
designs, where the holes act like lenses instead of like a mask.
But AFAIK nobody has ever made a tube with more than 3 colours.
There's a better chance with CRT projectors, where each colour
has its own tube. You can achieve a wider gamut that way, but the
added benefit is not very high because only few natural colours
are outside the EBU/sRGB gamut. Mostly cyan parrots and such..
Most multi-primary proposals are about field-sequential colour
engines, like built around DLP or LCoS. Then colour gamut is not
the only potential advantage, there is also luminous efficiency
to be gained. E.g. without a yellow primary, the yellow part of
the lamp spectrum is necessarily wasted. Or if you add a white
primary, then you can achieve a much higher peak brightness.
Yes, there is a (small) brightness penalty for saturated colours.
Lastly, there are now proposals for multi-primary direct-view
LCD panels. Samsung has shown RGB+White, and recently also a 6-
primary RGB+CMY LC display (SID2004). Stay tuned, I would say.
Greetings,
-- Jeroen.
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| From: Jeroen H. Stessen | E-mail: Jeroen.Stessen@xxxxxxxxxxx |
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