I have never really had to worry about that problem. Most modern games consoles (since the
Dreamcast onwards) have built-in screensavers and/or cut the display image by about %50
after being left alone for 10 minutes or so.
I do however, have a Dell Latitude C610 with (as far as I know) an LCD screen. Now I had
heard that LCD's couldn't get the 'burn' problem. I was proved wrong
though, as I spent a long time (a few hours) downloading and installing software back when
I first got it (2nd-hand from epay) around February 2007.
Now whenever the screen goes all one colour, especially black, I notice a lighter
rectangular patch where the downloading window had been left. It's not visible at any
other time thank goodness.
Also, a year or so ago, someone accidentally left a computer on at work over the weekend
(so atleast 48 hours) and the screensaver didn't kick in. Now theres a permanently
faint Windows taskbar and icons viewable all over the screen!
Regards,
Andrew B
aliensrcooluk at yahoo.co.uk
--- On Mon, 15/12/08, Mr Ian Primus <ian_primus at yahoo.com> wrote:
From: Mr Ian Primus <ian_primus at yahoo.com>
Subject: Screen burn. How long does it take to affect a tube?
To: cctalk at
classiccmp.org
Date: Monday, 15 December, 2008, 7:49 PM
Everyone has seen old monitors/terminals with text clearly burned into the
screen, or a grid of fuzzy boxes where the character cells line up, wear from
many years of use and abuse. While graphic color tubes can and do develop screen
burn (the Macintosh menu bar, and Windows taskbar being commonly found etched
into discarded color monitors), the burn-in problem seems more prevelant on
older, monochrome tubes.
I use a fair number of old monochrome monitors, and a couple of terminals I use
every day. Yesterday, I accidentally left a computer and it's monochrome
monitor running unattended for about four hours (I forgot to shut it off/got
distracted). When I returned, I carefully examined the areas where text had been
on the screen, and could not detect any burn-in, although I can tell that the
left side of the display has an oh-so-faint browning to it. Now, I am almost
positive that this was there all along, after all - this thing lived a hard life
before I found it. But, it got me thinking, how long does text need to be on the
screen to burn into a monocrhome tube? Four hours doesn't seem like enough
time - otherwise every PC monitor would have the WordPerfect ruler burned into
it.
I did some searching, but of course, could only turn up things relating to
modern plasma screen TV's, which apparently suffer similar degredation from
use.
Were there any studies conducted, or actual ratings for picture tubes like
this? The sort of tubes I'm referring to are standard monochrome CRT's,
like the ones used in terminals and monitors in the early 80's.
On a similar note, I was playing with a system test utility program for the
Commodore PET. It tests the RAM and ROM, loops continuously and displays the
test results and running time on the screen. The Commodore PET also uses this
sort of monochrome picture tube - and unlike most other machines, you can't
shut off just the screen and leave the computer running. So, this test program
alternates every second or so between normal and inverse video modes. Now, since
the screen is flashing, it shouldn't damage the phosphors - since it is my
understanding that the phosphor burn phenomenon isn't so much the phosphors
wearing out, but related to them being constantly excited, and therefore heating
up and darkening. Is this correct thinking? While I don't plan on running
this test for extended periods of time, I do wonder about it's potential
effect on the screen, if any.
It's interesting to see what's already burned into screens though, it
gives an insight into what the computer used to do. I have terminals with logon
promts burned into them, menu systems, and at least one with a dire
confidentiality warning permently etched into the tube. I've got a Monitor
IIe with "Apple //e" burned into the top - clearly someone left the
computer on without a disk in it for a very long time to get that clear of a
burn in.
So, like I said, I just got curious about the whole thing, and figured I'd
see if anyone else knew more on the subject. Obviously, I always try to be
careful and shut things off when I'm not using them, but, you know, mistakes
happen.
-Ian