I think that most people forget that TVs for home consumption are not
meant to be viewed when bright lights are on. Typical illumination in a
home while watching TV is expected to be between 50 and 200 lux afair.

This is not the case for projection units designed to work in daylight.
The difference is from ~80W input to a 21" TV set to >400W input to a
projection unit with 2.2 meter screen. The screen projection should lose
(power should be ~16x for same brightness) but it does not because the
viewing angle is narrower and other efficiency factors. It can appear
twiec as bright as a TV alongside it. (the TV only puts about 20W of power
into the screen luminance proper out of the 80 input). Did anyone notice
how displays at exhibits carefully place TVs, plasma screens and
projection screens so they can't be watched and compared at the same time
by the same person ? ;-). (I know there are exceptions, and I know who
they are).

The lifetime of four years of a new low cost picture tube is not very low,
assuming that the unit was operated all the time. Do the hours count and
you will see that the hours count will approximately match or exceed the
expected hour count for these devices.

Older tubes had much thicker cathode coating than now and it was of
different formulation (pretty hot afaik ;-). Nowadays the coatings are
thinner and more 'optimized'.

The Trinitron has slightly higher efficiency because it uses a vertical
wire mesh instead of a slotted mask afair. This has higher transparency to
electrons. I am using a trinitron screen both here and at work so I
know ;-).

Peter

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