Originally Posted by kontai69
From the research I've done, the problem you are describing is called backlight leakage/bleeding. I found out it was a major issue with some early Dell LCD monitors.
My 32" Sony KLV-32M1 LCD TV had this problem when I first got it a year ago. There were 4 palm-sized "blotches" around 6" from each corner of the screen. They were most noticable in dim ambient light and when the set was displaying a blank black screen. It drove me nuts when I was watching movies with dark backgrounds and shadows.
I hypothesized that the cause of the problem was due to localized pressure points on the LCD panel which displaced some of the liquid crystal matrix underneath. I came up with this idea because if you ever pressed against an LCD screen with your finger, you would notice it turns white where you touch it. The same could be happening if there is uneven stress on the panel assembly (as a result of shipping?).
With this hypothesis in mind, took a microfiber cloth and physically "massaged" the screen to even out any stress points. I applied firm pressure but not excessively so as to not damage the screen. I kept one hand on the back of the TV to counter the pressure of the other hand. Lo and behold, the blotches disappeared!
As Fiddle linked, I too have this problem on my 46" XBR. If anyone can confirm this to be a workable solution, I'll definitely give it a go. However, I'm hesitant to try this on a $4,000 LCD. Could it possibly be the screws on the rear of the assembly being overtightened? I see two that are right in the corner. One looks remarkable tighter (or looser, depending on the screw you look at) then the other. If this problem is as pertinent as you say in former LCD's, and it's most prominent in the corners, could one (or both) of these screws be an "adjustment" to allow them to fix this annomaly? Or perhaps the extra screw is just to hold the glass bezel in place.