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Posted by Bob Myers on 11/07/07 00:20
"Rita Berkowitz" <ritaberk2O04 @aol.com> wrote in message
news:13j1r4ntiajosc0@news.supernews.com...
> Not from an end-user's perspective when the LCD monitor dies quicker than
> the stated MTBF. Most unsuspecting consumers are falsely lead to believe
> that the whole unit has a chance of lasting the stated MTBF.
And the "M" in "MTBF" stands for what, again? That's right
- it's the MEAN time before failure. Obviously some units will
fail before this time is up. Some will last longer. All in all, though,
field data very strongly shows that the reliability of LCD monitors
is quite comparable to that of CRTs, if not at this point better.
> This sounds like one of them hairs that is to thin to split. The bottom
> line is that pretty much any other part than a blown fuse in an LCD
> monitor
> makes it uneconomical to repair. As for CRT itself, that is a very robust
> component and has less chance of failure provided it wasn't dropped. Most
> of the time it's the surrounding components that need fixing/replacing.
Right, in terms of hard failure. But the CRT itself slowly becomes
unusable due to a loss of cathode emissivity and phosphor
brightness with age (well, technically, it varies with the amount
of current delivered by the cathode, but we might as well simply
say "age").
>> 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.
>
> Interesting. I've split apart many LCD panels and I've found the color
> correction filters in between. This even holds true with the design of
> the
> light engine in LCD projection TVs. It's more practical and efficient to
> correct the light source before it hits the LCD than it is to try to
> correct
> everything after it has passed through the LCD. The surface filters you
> are
> referring to are there for antiglare.
No, they're the individual color filters that are formed over each
subpixel in the array. I think you're confusing the brightness
enhancement films, diffusers, etc., with the color filters. It is simply
not possible to create the color filters in a direct-view LCD as a
layer that's physically separate from the panel - the alignment would
be a nightmare. There ARE, in addition, polarizers, anti-glare, etc.,
added to the basic panel, but the color filters are most definitely
a part of the panel itself. I don't really care how many LCD panels
you've "split apart" - I've watched the panels being made in the LCD
fabs, and have been working with this technology for a good 20 years.
> It would be nice, but some of us only have the luxury of reverse
> engineering.
In that case, you should be very careful about the conclusions you
draw from this "reverse engineering," in the absence of other
knowledge and experience regarding the technology.
Bob M.
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