Do Later LCDs Need Screen Savers?

bwdunn asks: "Do we need to run screen savers again to prevent the burn-in we saw on the very old CRTs? Dell's latest and greatest laptops, the Latitude D800 and Inspiron 8500 both suffer from horrible screen burn-in problems with burn-in visible after as little as 2 hours. Dell claims this is an industry wide problem. The high end displays from Apple also seem to have this problem. I have never seen this problem before 2002. Is this something new due to inferior LCD screen manufacturing compared to screens from just a few years ago?"

Comments

We've been observing this problem too

[David McBride]

The local department has recently been replacing the CRT displays in the computing labs with LCDs as part of their rolling upgrade cycle. So that it's easier to distinguish between a working PC and a dead one by whether or not the login screen is showing, we turned off the screensaver -- thinking that ``there's no phosphor to get burned in.''.

Doesn't appear to be true, sadly. A number of displays are now starting to get a burnt-in image of the login window.

Time to update the login manager scripts with a small call to xscreensaver, methinks..

The answer is in the fourms...

[Sancho]

The answer (at least for Dell) is in the forums that were linked to in the summary. Send it back. Get a new one. If the new one also burns in, do it again. Do it until you get an LCD that doesn't burn in. It's a major hassle, but it appears that all of their LCDs don't suffer from this problem, thus it's unlikely that "new" LCDs have this problem. Looks like a bad batch or poor construction somewhere in the laptop/LCD, since replacing the LCD will eventually get rid of the problem.

Article (in German) with picture of burn-in

[Lars T.]

Here. Picture after 15 hours of burn-in and 51 hours of uninterupted reconditioning.

Depends on how the display is made

[Sunlighter]

Actually it can be done either way. A liquid crystal, when powered, rotates the polarization of light 90 degrees. When unpowered it has no effect. So, a LCD display is made from two polarizers and a layer of liquid crystals. Consider this:

• Horizontal polarizer + horizontal polarizer = transparent (white)
• Horizontal polarizer + vertical polarizer = opaque (black)
• Horizontal polarizer + liquid crystal + horizontal polarizer = black when powered, clear when unpowered
• Horizontal polarizer + liquid crystal + vertical polarizer = clear when powered, black when unpowered

Whether white or black is powered depends on the way the display is made.

Re:Turning monitor off

[sigwinch]

Many household devices today use more power when their state is changed than they would if they were just left on constantly.

Wrong. The turn-on surge for all common household devices is a few times normal power, and only lasts for a fraction of a second. The energy cost of the surge is negligible.