LCD screen: Can Image persistence be corrected?
July 16, 2007
Screen burns and Image persistence
LCD screens may sometimes be afflicted by a temporary problem known as image persistence. As the continuous, static image produces so called ‘screen burns’ on a plasma screen, in a similar way, they cause LCD screen to display the previous image or part of it on the background thus producing picture of poor quality.
Difference between screen burns and Image persistence
Screen burns of CRT monitors and plasma TVs are often permanent as the phosphors that produce display become pre-maturely old or damaged by the continuous display of some bright, static image on the screen. Screen burns are not reversible because the phosphors cannot be replaced and this leads to permanent imprint of the image on the screen. This is what is normally called ‘screen burns’.
On the other hand, image persistence or image retention on a LCD screen, though produced similarly, is hardly permanent and reversible if you take some remedial steps. LCDs use liquid crystals that produce images using a backlight source. When the voltage is passed through the crystals, they twist and relax depending on the varying voltage. When you let any image on the screen for longer period, the same voltage continues for same amount of time resulting in crystals to stay in one state. So, when the next image appears on the screen, the colours on the affected area will still have a faint imprint of the previous image.
Why Image persistence occurs on a LCD screen?
Any static images that are displayed for a quite longer time like tool bars, program icons or background images tend to produce image persistence on LCD screens.
Fortunately, image persistence does not produce permanent effect on LCD screen, as it is caused by the state of crystals which tend to change depending on the voltage used. When different images appear on the screen they usually prevent image persistence from occurring. However, if any static image is left for a longer duration to cause image persistence, it produces permanent imprint of image only in rare circumstances.
Preventive measures
Image persistence on LCD screens can be prevented by observing certain methods which are given below:
- If you use LCD screens with your PC for much longer time, you can use appropriate power settings in your PC, so that LCD monitors will be off for a few minutes after prolonged use.
- When you are using your monitor, either make some screen saver to rotate over the screen. Generally some graphic images or some blank screen savers are generally preferred for this purpose.
- If you use any background images on your desktop, it is highly recommended that you change them periodically to prevent image persistence from occurring.
Corrective measures
Image persistence can not only be prevented but also can be rectified using following methods:
- If a image persists on your LCD screen, you may keep your LCD screen unused for hours together. If it still persists, turn it off for a few weeks. Often it enables your LCD screen to correct the problem itself.
- Any graphical image used as screen saver often helps to remove the image persistence if it is kept rotating over the screen for longer periods.
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