toshiba 37" lcd

[F Murtz]

my Toshiba 37" lcd tv screen has a dark curved blurry mark about 150mm
long 10 mm wide at widest part,near centre of screen.
It is only visible in certain screen colours,not pure white but an
overall off white.It is not very visible during normal watching,only
when screen is light over the area of the mark.
It is not on the surface.
Any ideas why ? Is it likely to get worse?

 

[?]

my Toshiba 37" lcd tv screen has a dark curved blurry mark about 150mm
long 10 mm wide at widest part,near centre of screen.
It is only visible in certain screen colours,not pure white but an
overall off white.It is not very visible during normal watching,only
when screen is light over the area of the mark.
It is not on the surface.
Any ideas why ? Is it likely to get worse?

Does it change shape or disappear when you put slight pressure on the screen
near that spot?



I've taken apart faulty LCD screens and noticed they're made of several
sheets of plastic.

Some are light dispersant & some are Polaroid/polarised sheets over the
"sandwich like" glass enchased liquid crystals.



I'm guessing these sheets may have sagged /stretched due to heating from
normal

operation of the LCD, or due to gravity. Ie. Rather than being flat, the
sheet is slightly warped or curved.



Gently press on the spot to flatten it & see if that makes any difference,
if it does that's your answer.

 

[F Murtz]

Does it change shape or disappear when you put slight pressure on the screen
near that spot?



I've taken apart faulty LCD screens and noticed they're made of several
sheets of plastic.

Some are light dispersant& some are Polaroid/polarised sheets over the
"sandwich like" glass enchased liquid crystals.



I'm guessing these sheets may have sagged /stretched due to heating from
normal

operation of the LCD, or due to gravity. Ie. Rather than being flat, the
sheet is slightly warped or curved.



Gently press on the spot to flatten it& see if that makes any difference,
if it does that's your answer.

I just tried but I can not catch it in the act long enough. It is right
in the centre of the action and I need a slow movie with the right shade
when the centre of the screen is vacant.

 

[F Murtz]

It could be a finger mark in dust. Did you try cleaning the screen?

It is not on the surface.
I tried massaging the screen gently and thought it was better for a
while but it is not.

 

[F Murtz]

google "lcd mura"& see if any of the images you see are similar to what
yours is doing. seems like a manufacturing issue with some lcd screens.

cheers,

timbo.

It is very like the second picture in the row of four,fourth down in my
search.