Vertical shadow on the screen

[Walker]

I first noticed this a few months ago and it's been getting clearly worse since then. When I turn on the monitor, I notice this faint vertical "shadow", around 10mm wide, mostly visible on grey color. Not really too distracting unless I look for it. BUT, after a couple of hours it starts to get worse. So it looks like this in the morning:



And after 10 hours like this:



Does anyone know what could be causing this? It doesn't seem like a problem with a column of pixels or something like that because the line is not very well defined at all. I'm guessing the fact that the issue gets worse as time goes on means it has something to do with heat because the shadow is always almost invisible when I turn the monitor on after it's been turned off for a long time. If it was something wrong with backlight lamps, surely it wouldn't look like this?

 

[plugwash]

IIRC most monitors use a linear backlight tube or array of LEDs along one edge of the screen and then use optics to spread the light vertically. So if there was an issue with the backlight that only affected a small section of it's length it would end up as a line on the screen.

Do you know what sort of backlight your screen has? I could easilly see a LED array doing this if there was a problem with the heatsinking of one of the LEDs.

 

[Walker]

The backlight is CCFL. I found a pdf with all sorts of info of the actual panel used and in the backlight section it says "The back-light system is an edge lighting type with 2 dual CCFT..." and it has this diagram:



Not sure whether this meants the CCFL tubes are located at the top and the bottom of the panel. If it is one of the tubes that is indeed the problem, do you think I could fix that by myself (providing I manage to find one of course)?