For over 2 years now ive been trying to find out exactly what this 'Dirty Screen Effect' is that seems to affect almost all LCD displays.... ive had 3 LCD's and all of them had it too some extent... A lot of people don't realise they have it....like my dad... Ive noticed loads of LCDs with it in stores aswell and expensive brands are not immune from it either...
Ive thought about it and searched the web but found no information that supports a possible explanation of what it is and how its caused...
I have come to my own conclusion and would like others to Input on this to see if we can pinpoint what this horrible on-screen artefact is that we have to put up with - of course I could be totally wrong, this is just me thinking out aloud....
...Cell Warping...
it seems to happen because a 'group' or 'band' of pixels (cells) have become slightly 'warped' either with heat or just shear flexibility from the weight and orientation of the thin screen that the light passing through these 'cells' is no longer in direct line of sight and 'appears' as slightly darker patches on the screen to the viewer, I think it is more likely to be from flexibility and weight of the LCD panel itself and can be worsened with prolonged viewing (heat from back-lighting making it worse) as was the case with my first LCD, if you held up a 42" LCD Panel itself in your hands it would warp and twist and the light in the bends/twists would darken (just like your PC/Laptop screen does when you press your finger on it) ...
- this would explain also why we only see it with light/pastille colours and mostly noticeable when the object/camera pans around as the colours in the image are bright and uniform, but when they pass through the 'affected area' on screen they stay slightly darker than the rest of it.
This obviously can not be 'repaired' and seems to be a flaw with most LCD screens, the only way it can be overcome is if the manufacturers come up with some new type of panel that is stronger/firmer
My first LCD was more in a uniform banding pattern of blotching rather than random blotches like my last and current LCD, the first one didn't have any noticeable banding at first but after prolonged use (9 months) it started to appear and got worse, the uniformity of it suggested it was the LCD screen becoming weak from heat of the backlight and causing it too warp...
again I must stress this is just me thinking out aloud but I do think its a good explanation of what could be happening and Iam calling it Cell Warping until a better explanation comes along
anyone else care to add to this...feel free