Finally got up the nerve to buy an LCD television. I get it home and set it up and BLAM...huge light spot in the middle. I have adjusted the settings, including the brightness which has helped, but it is still there just as clear as a bell. I am so bummed! I plan on bringing it back and exchanging it but I'm wondering...what causes this to happen????
Back-light bleed through is caused by an improper seal between the edge of the LCD screen and the TV Frame. Back-light bleed through is usually along the edge of the TV's screen, not in the middle of the screen.
The problem that you have described could be "mura"; a traditional Japanese term that means inconsistent. LCD screens (due to quality control issues) can have inconsistent light penetrating the screen. Your TV sounds like an extreme condition of "mura".
Additional details: Nice link in the following response; too bad it's for CRT tube TVs and NOT LCD TVs like that referenced in the question!
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