Laptop LCD goes partially black. Help

[sandia911]

Laptop LCD goes partially black. Help

Something really wierd and scary happened last night to my laptop's LCD screen. I woke up to find the righthand bottom corner electronically stained with what appared to be black dissolve. There was nothing physically on the screen but it looked like someone had smeared black tar or ink on my computer screen.

Luckily, tapping the screen with my fingers caused the darkness to gradually disapate (now it's all gone), but I'm still left wondering what the hell happened. Is this a serious issue with my LCD? Does it need to be replaced? The computer is only 1.5years old.

Other points to mention about the laptop:
I do keep it on a lot (mostly for downloading)
It has a loud (hot) fan which causes some overheating, and in order to keep the noise down (because I stay with many people), I sometimes close the laptop and cover the computer with as pillow or a blanket. It reducez the fan noise and I make to sure to always leave a pathway for the hot air to escape.

I've been doing this for a while now, and the blackness only appeared last night.

What is the blackness? What caused it? How can I avoid seeing it again? Also, if it does have to do with the overheating caused by the computer's fan (what can I do to keep the noise down without causing such a disruption with the LCD)?

[clocker]

Your screen has "backlights"...essentially, little flourescent tubes that shine through the pixels.
Sounds like one of your backlights is going wonky and when it does it's time for a new screen.
At that point I'd reevaluate how much money you want to sink into your current unit as opposed to a whole new lappy.

Smothering it with a pillow is not a great idea.
Your idea of a suitable pathway for air intake/exhaust and what it really needs are probably very different.

Just another reason I hate laptops.

[lynx]

I disagree with clocker's diagnosis, but just in case he's right you can get a replacement backlight quite cheaply.

However, I think it is far more likely that you've simply overheated the polarised screen. An lcd screen consists of a polarised screen (the polarisation runs the same way right across it) and the individual pixels whose polarisation changes.

If you overheat the polarisation screen it stops transmitting light, but it comes back as it cools down. It sounds like you've overheated just one corner, and once cooled the symptom disappears.

I did exactly the same thing with an LCD watch once, by leaving it in the sunlight in my car. When I returned it was too hot to wear, and the face was totally black. After a couple of hours it was operating perfectly. However, I don't recommend you do this repeatedly, as it may eventually cause permanent damage.

As clocker suggests, keep the pillow well away. The cooling system on laptops is fairly critical, and assumes that there will be some heat dispersal via the case.

[Seedler]

I disagree with clocker's diagnosis

Clocker vs. Lynx=WW3.