So what causes BLB - backlight bleeding?

[csorrows]

I see so many people talking about BLB on LCD monitors. I have an older Xerox LCD at home myself with some BLB.

But what CAUSES it?

What happens to the panel to make the backlight shine through more? Is the light getting brighter over time, or is some coating deteriorating on that panel to make more of the light shine through?

I'm just curious, because I see so many posts about BLB, but never any explanation for what causes it.

 

[j0j081]

I think it is when there are differences in pressure between the panel and the lighting or whatever else is behind it.

 

[E.T]

But what CAUSES it?

That always shining (power consuming) backlight and fact that LCD matrix can't block all light.
That's why many of us are waiting for OLED and FED/SED displays because those throw whole bleeding backlight (and slow response time liquid crystals) away.

Pressure difference inside LCD panel is behind some of BLB variation between different parts of display. You have seen similar effect if you have noticed that touching screen even very lightly is enough to change colours/brightness at that point.
Also of course uneven backlight causes BLB variation.

Here's rather good article about LCD defects in general and what causes price differences between monitors which appear to use same panel.
http://www.behardware.com/articles/589-1/panels-a-carte-mura-components-dead-pixels.html

 

[XST1]

So brightness level isn't going to make the backlight bleeding worse then?