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Posted by Bob Myers on 11/06/07 18:27
"Rita Berkowitz" <ritaberk2O04 @aol.com> wrote in message
news:13j0lnpn3dqvr43@news.supernews.com...
>>> And you think the MTBF of a CRT monitor is...what?
>
> It's irrelevant.
It's completely relevant. You claimed that the "longevity"
of LCD monitors was poorer than that of CRTs - therefore
the MTBF of the CRT technology is most definitely part of
that equation.
> Stated MTBF of LCDs would have you believe the 50K-100K
> hours.
And the MTBF of the panel itself DOES reach and/or exceed this
point. The weak point is the backlight; replaceable-backlight designs
have been produced (although few customers are willing to pay the
incremental cost), and it's a lot simpler to replace an LCD backlight
tube than to replace the CRT itself in a monitor (which has a
comparable lifetime to the BLU). LED backlighting, now coming to
market, will change this situation for the better as well.
>> The spectrum of even "full-spectrum" fluorescents is rather
>> a significant compromise over reference sources such as
>> tungsten lamps. Traditional fluorescent tubes have a giant
>> green spike (or two). We used to use magenta-color plastic
>> tubes over the fluorescent lamps to try to knock down the green
>> to allow us to shoot film or video. Some professional video
>> cameras (particularly those used by news videographers)
>> have special settings to compensate for fluorescent illumination.
>
> You got it.
But, as I noted, the concerns re fluorescents for illumination are
utterly irrelevant re their performance as LCD backlights. What
you care about in the backlight situation, from a performance
standpoint, are the primary chromaticities and white point you
can achieve, and the peak brightness. (Black level is more a
function of the LCD itself.)
> No, they are using basic "gel" type filters between the backlight and LCD.
No, they're not. First, the color filters are NOT "between the
backlight and the LCD." The color filter layer is produced on
what is most often the "top" substrate (glass panel) that forms
the LCD panel itself. The filters themselves are created via a
photolithographic process and are basically a specially-made
colored photoresist material.
> No special technology here. Bust a few dead LCDs apart and you learn more
> in 5-minutes than could be learned from most internet sites.
Actually visit a few LCD fabs, and you might learn even more.
Bob M.
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