Screensavers
Newzed
Posts: 2,503
I know screensavers prevent "burning" with a CRT monitor.· Are they really necessary - or helpful - with an LCD monitor?
Sid
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Sid Weaver
Don't have VGA?
Newzed@aol.com
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Sid
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Sid Weaver
Don't have VGA?
Newzed@aol.com
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Comments
Actually, over time an LCD screen will "burn in " and have a " ghost " image on them as well, unless you use a constantly changing
screen saver.
Bob
Under normal usage I will agree, but most of the LCD screens I have seen with burn in, or ghosting
have been from industrial usage where there is a menu, or text up on the screen 24/7..
Bob
Screen "burn" on any ordinary CRT is caused by the repetitious, persistant and constant passage of the charged electron gun beam over the same exact area of the reverse side of the CRT face. This interior area contains an even ·phosphor.coating when it is manufactured. Over time these phosphors will burn off of the inside face of the CRT. Once the phosphors·are removed, an image will form where the phosphors used to be. It is an image of absense (missing phosphors), not an image of presense.
A screensaver promotes more even distribution of this charged electron gun scanning on the inside surface of the CRT, or should I say that it prevents the constant and repetitious electron imaging on exactly the same places that an idle screen WITH an image would provide. So to speak, it "randomly" scatters where the charged electon gun will land over a period of time.
CRT's operate by use of a horizontal and vertical scan. This is a physical effect and is the track of the electron gun on a continuous basis across the interior of the envelope face; that which contains the phosphor coating. If the electron gun is charged when it hits a particular phosphor group (pixel) that area will light up. If not, it stays dark.
There is no such physical "scanning" per se in an LCD monitor. Rather, multiplexing is done to illuminate different portions of the LCD pixels by applying voltage through the LCD leads, and energizing the substrate underneath the LIQUID where the pixels are intended to be illuminated. Those areas which remain without a charge are left dark. The reverse is true on an inverted screen (so called negative image).
L-C-D means LIQUID CRYSTAL DISPLAY. The image you see in an LCD is NOT on the inside surface of the lens as it is on a CRT, but IN the LIQUID contained within the cavity of the LCD. Therefore, there is really nothing to :"burn" as there is in a CRT. There are no phosphors or anything like it in an LCD.
In summary, there is no need to use a screensaver on an LCD monitor, unless you happen to enjoy the images it provides.
Regards,
Bruce Bates
Post Edited (Bruce Bates) : 1/28/2007 9:36:26 AM GMT
Here is an excerpt from www.displayconsultants.com/presentation/spie.pdf ....
Just doing a search on Google for "LCD aging" and there will be a LOT of info..
Bob
Post Edited (Robert Kubichek) : 1/28/2007 4:00:59 PM GMT
The backlight in my PDA(Psion netBook) is believed to have a 'half-life' of 700 Hours...
That is, after about 700 Hours, it will only emit about half the light as it did when new, on average.
(This is on full brightness, of course.)
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Don't visit my new website...
I don't know of anyone that was speaking of AGING issues, I sure wasn't. The topic of the conversation was the use of screensacer to prevent BURNING of an image on an LCD.
Regards,
Bruce Bates
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The use of "burning" is relative... I equated it with " aging ", or " ghosting "...
Take a look at an LCD screen that has been used for industrial controll....
1st when it is off, then when on...
When it is off, on aged screens, you will notice a ghost image on the screen
that matches the screen when it is on.
When it is ON, if you go to a screen that is different that the "long term screen",
you can notice color/brightness changes that are a ghost of the "long term screen"..
Also, I am surprised that none of the LCD manufacturers are to my knowledge using LED
backlighting on laptop, or desktop LCD displays..
Bob
A 21" lcd monitor with LED backlight: www.necdisplay.com/products/ProductDetail.cfm?Product=425&ClassificationFamily=1&Classification=3
Harrison
Post Edited (Harrison.) : 1/28/2007 7:35:45 PM GMT