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Adapting preventative measures for a move from CRT to LCD

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Anonymous
a b U Graphics card
December 14, 2004 12:13:35 AM

Archived from groups: comp.sys.ibm.pc.hardware.video (More info?)

After using CRTs for years, I more or less began to understand how to
treat them to lengthen their lives and improve performance. I figured
out that:

- Leaving a CRT on when it is not in use is bad.

- Leaving fixed images on the screen for very long periods is bad.

- A dark screen preserves the CRT longer than a bright screen (most
screen savers seem to be designed around this premise).

- Switching the CRT to power-saving mode probably is best for long life
(eliminates the thermal shock of a complete power-off/power-on cycle,
but reduces wear and tear on the cathode when the CRT is not in use).

- CRTs don't like magnetic fields, and should be occasionally cycled off
completely and turned back on to degauss the screen (if there is no
degauss button).

- For extremely critical work, CRTs have to be calibrated after they
warm up for an hour or so.

- CRTs don't like anything sitting on top of the tube (I'm surprised how
many people stack magazines or papers on top of their CRTs).

- CRTs like low resolutions and low scan frequencies better than high
resolutions and high scan frequencies (I think?).

Now ... the question that arises is how to modify all this for an LCD
flat-panel screen:

1. How long a duty cycle should a LCD have? How long should it be left
on, unused, before it's best to turn it off? I'm thinking here mainly
of the backlight, which I assume is the major wearing component over
time. If it's just a fluorescent lamp, it probably likes long duty
cycles and suffers most when first turned on.

2. Do fixed images on the screen do any damage over time?

3. Is a mostly-dark screensaver really a good idea? I mean, the
backlight is always on, so a dark screen really is just absorbing the
backlight and heating the screen. Would it make more sense to use a
screensaver with a mostly-white screen? Or is a screensaver really
worth bothering with at all? What about a blank white screen (minimal
heat and equal settings for all pixels)? What puts the most stress on
individual pixels?

4. Is there a difference between power-saving mode and being completely
off for a flat panel? If so, which is preferable for long life?

5. Do LCDs shift significantly in performance over time? In what ways?

6. I presume that LCDs don't care about scan frequencies or resolutions,
since nothing is really being scanned, anyway. True? I imagine that
just running the screen at its native resolution all the time is best,
if there's any difference at all (?).

What does the brightness control adjust on an LCD? Does it actually do
something to the backlight or does it just control how the pixels are
driven? Does lower brightness extend life?

--
Transpose hotmail and mxsmanic in my e-mail address to reach me directly.
Anonymous
a b U Graphics card
December 14, 2004 12:13:36 AM

Archived from groups: comp.sys.ibm.pc.hardware.video (More info?)

> Mxsmanic <mxsmanic@hotmail.com> wrote:

> - Leaving a CRT on when it is not in use is bad.

That depends. Frequent power-cycling can be more stressful.
I used to leave mine on unless I was not going to use it
for at least 2 hours.

> - Leaving fixed images on the screen for very long periods is bad.

Definitely.
Changing your wallpaper from time to time is wise.

> - A dark screen preserves the CRT longer than a bright screen

"darker", but not "black". Using a screensaver of video
black level can "poison the cathode". I used Windows
Starfield - minimal signal, burned in all screen locations
about equally.

> - Switching the CRT to power-saving mode probably is best
> for long life ...

I'll let others opine here. I never really trusted it.

> Now ... the question that arises is how to modify all
> this for an LCD flat-panel screen:

Indeed. The answers may be interesting.

--
Regards, Bob Niland mailto:name@ispname.tld
http://www.access-one.com/rjn email4rjn AT yahoo DOT com
NOT speaking for any employer, client or Internet Service Provider.
Anonymous
a b U Graphics card
December 14, 2004 1:41:12 AM

Archived from groups: comp.sys.ibm.pc.hardware.video (More info?)

Bob Niland writes:

> That depends. Frequent power-cycling can be more stressful.
> I used to leave mine on unless I was not going to use it
> for at least 2 hours.

At work I left CRTs on all day, then usually turned them off at night.

At home I originally turned the CRT off at night, or when I left the
house for any period of more than 90 minutes or so. Later, as the CRT
aged, I let it switch to power-saver mode instead, figuring that it
would last longer if the filament stayed warm and shocks were avoided.

Overall, it irritated me that the CRT was really just a big,
old-fashioned vacuum tube. Flat panels have been around for forty years
and they _still_ aren't up to match CRTs. How long will it take?

> Definitely.
> Changing your wallpaper from time to time is wise.

I used screensavers and changed wallpaper regularly. I never actually
saw a burned-in color monitor outside of ATMs and things like displays
at airports, but I didn't want to take any risks.

> "darker", but not "black". Using a screensaver of video
> black level can "poison the cathode".

Hmm ... that's interesting! How does the "poisoning" happen?

I never used completely black screensavers, mainly because it was too
hard to see if the CRT was on or not.

> I'll let others opine here. I never really trusted it.

I wonder if anyone has ever done controlled tests. On the one hand, you
avoid the shock of heating a cold tube suddenly. But at the same time,
there must be some wear and tear if the filament is warm (but how warm
is it it kept?).

> Indeed. The answers may be interesting.

If anyone has done any experimenting yet.

--
Transpose hotmail and mxsmanic in my e-mail address to reach me directly.
Anonymous
a b U Graphics card
December 14, 2004 1:41:13 AM

Archived from groups: comp.sys.ibm.pc.hardware.video (More info?)

> Mxsmanic <mxsmanic@hotmail.com> wrote:

>> "darker", but not "black". Using a screensaver of video
>> black level can "poison the cathode".

> Hmm ... that's interesting! How does the "poisoning" happen?

Although Bob Myers just wrote on this lately, here's
one of his full explanations from some years ago:
<http://groups-beta.google.com/group/rec.audio.tech/msg/...;

--
Regards, Bob Niland mailto:name@ispname.tld
http://www.access-one.com/rjn email4rjn AT yahoo DOT com
NOT speaking for any employer, client or Internet Service Provider.
Anonymous
a b U Graphics card
December 14, 2004 2:06:23 AM

Archived from groups: comp.sys.ibm.pc.hardware.video (More info?)

"Mxsmanic" <mxsmanic@hotmail.com> wrote in message
news:fq2sr0pjtld256it6gk9sjb0pkf3ljmu1m@4ax.com...
> Overall, it irritated me that the CRT was really just a big,
> old-fashioned vacuum tube. Flat panels have been around for forty years
> and they _still_ aren't up to match CRTs. How long will it take?

Well, no one ever said that things had to be "better" just because
they were newer. I seem to recall that this thing they call the
"wheel" has been around for some time without significant
fundamental improvement....:-)

Flat panels in the sense of the modern color TFT-LCD have really
been in volume production for only about 15 years or so; there
have been LCDs of other types for longer than that, but please keep
in mind that the first things you might realistically call an LC display
(back in the 1960s) were pretty much laboratory curiousities, at
about the same level of development as the really early CRTs.
(And does anyone want to take a guess at how old the CRT is?)

For that matter, "flat panel" covers a very wide range of technologies,
including some that aren't all THAT different from the CRT itself
(color plasma, for example, or better yet the color FED - which
STILL has not made any significant inroads in the commercial
display markets).

Hang in there, though - better days ARE coming.

Bob M.
Anonymous
a b U Graphics card
December 14, 2004 3:13:20 AM

Archived from groups: comp.sys.ibm.pc.hardware.video (More info?)

Bob Myers writes:

> Hang in there, though - better days ARE coming.

I hope so. My eyes have suffered through a lot of crummy monitors, even
though I try to buy the best I can afford. There's no such thing as a
monitor that's _too_ good.

--
Transpose hotmail and mxsmanic in my e-mail address to reach me directly.
Anonymous
a b U Graphics card
December 15, 2004 12:30:43 AM

Archived from groups: comp.sys.ibm.pc.hardware.video (More info?)

Bob Myers writes:

> Solid state backlighting and other technologies are coming, but
> certainly are NOT mainstream yet (for the u$ual rea$on$)....

What ever happened to electroluminescent panels? I remember reading
about them years ago but they never seemed to gain any currency.
Wouldn't they be well suited to flat-panel displays?

> Generally not a problem. Again, the best thing to do for all of
> this is to simply turn the thing off when it's going to be unused
> for extended periods - such as, don't leave the monitors in the
> office on when you go home for the evening.

Agreed. This is what I'm currently doing. I'm always nervous when I've
spent every cent on new equipment and cannot afford to have it wear out
or fail.

> Again, treat it much as you would a CRT.

Okay ... but I could never find a consensus on the question for CRTs,
either.

> I wouldn't have the
> "screen saver" (or whatever power-management features) set so
> that the thing is being power-cycled every five minutes or so in
> normal use, but I would certainly want it to be turned off if I were
> going to be away for a few hours.

Right now I have the power-saver feature set to two hours, in case I go
out and forget to turn the monitor off. Otherwise, when I leave I turn
it off directly myself.

> Between those, a lot will
> be determined by your work habits, and how annoyed you are
> at having to restart the thing if you find the screen has gone black
> on you. But don't overly-agonize about this; it's not worth the
> stomach acid.

At least flat panels are almost instantly on.

> Right. For whatever it's worth, I currently have my desktop monitor
> set to turn off after 20 minutes of inactivity. I figure by that time, it's
> pretty clear that I'm away in a meeting or whatever, and the monitor
> won't be needed for at least an hour. 10 minutes was just too short,
> as often it would blank on me in the middle of a longish phone call
> or some such.

Wow, that's really short. This is for a flat panel?

> That's the way to do it, for sure. Run the thing as low as
> you can without YOU seeing flicker. If anyone else is
> annoyed by this, consider it a feature, as it will keep people
> away from your desk...:-)

I discovered the same advantage when I switched my mouse to the left
hand (mainly so that I could use my dominant right hand for the graphics
tablet--but discouraging other users was a nice side effect).

> That was covered in another response I made today; if you need
> more info after reading that, I'll go in to this in more detail.

I saw the other explanation, which was excellent.

--
Transpose hotmail and mxsmanic in my e-mail address to reach me directly.
Anonymous
a b U Graphics card
December 15, 2004 2:30:18 AM

Archived from groups: comp.sys.ibm.pc.hardware.video (More info?)

"Mxsmanic" <mxsmanic@hotmail.com> wrote in message
news:r1jur0la949nallt9d80b6ti50v33kbvqe@4ax.com...

> What ever happened to electroluminescent panels? I remember reading
> about them years ago but they never seemed to gain any currency.
> Wouldn't they be well suited to flat-panel displays?

Yes, and there have been some EL backlights. They've failed
to displace CCFLs for a number of reasons, including cost,
reliability, and efficiency. There are some good white ELs
available now which could come close to equalling a CCFL
backlight in these respects, but there's little chance they can
displace the CCFLs at this point. Getting rid of those will
have to wait for a truly superior technology to come along.
There ARE some candidates we might see in a few years,
such as purely solid-state lighting (LEDs).


> Okay ... but I could never find a consensus on the question for CRTs,
> either.

Yeah, well, display engineers are a prettty cagey bunch...:-)




>
> > Right. For whatever it's worth, I currently have my desktop monitor
> > set to turn off after 20 minutes of inactivity. I figure by that time,
it's
> > pretty clear that I'm away in a meeting or whatever, and the monitor
> > won't be needed for at least an hour. 10 minutes was just too short,
> > as often it would blank on me in the middle of a longish phone call
> > or some such.
>
> Wow, that's really short. This is for a flat panel?

Right; my current desktop monitor is a 17" LCD, at least
in the office. At home, it's a 19" CRT, just because it
still works just fine, I have the space, and I'm fundamentally
a cheap sort....


Bob M.
!