[EXPERT TIPS][GUY KUO]
Burn-in or Screen-Burn with LCD Monitors
Burn-in like effect does happen with LCD monitors but they are correctable as Guy
explains below:
"The burn-in like effects refer to a memory effect which can affect LCD displays.
It isn't a permanent effect like that which happens with emissive phosphors.
Basically, the liquid crystal displays work by using electrical forces to align liquid
crystal molecules into a coherent direction which causes a predictable and controlled
polarization of light. Combining that with crossed, fixed polarizers, light filters and a
light source allows one to create the color images we see on LCD's. The one part of this
which gets forgotten is that the relaxed, incoherent state of the liquid crystal must be
returned to after the control charges are done.
If a LC panel holds a portion of the liquid crystal in the coherent state (black on
screen) the liquid crystal material can temporarily develop a tendency to stay in a more
organized manner than normal. Thus long term black on a LC display may create an area
which holds a persistent image effect that looks like a phosphor burn. Fortunately, if the
LC panel is allowed to be quiescent (off) for an extended time, perhaps one or two days,
the liquid crystal regains its normal characteristics. The effect reverses and the
apparent "wear" or "burn" goes away. Another mechanism I've run
across, but haven't verified, is a temporary charge problem on the driving transistors.
Again leaving the panel off corrects the problem." |
