Well either it burned out completely, which is sort of preferable, or it is now working again. Basically a grid of wires, sort of, goes to each and every pixel in an array that is addressed by the scalar. The signals from your GPU are addressed to each pixel and determines how much light to let through.
LCDs are basically light shutters. The Liquid Crystal is activated by electricity to 'close' and when current flow is stopped to let the backlight through. This is variable of course so that you can control each color pixel independently. Effectively they are controlling light through polarization by aligning the crystals with a current.
Occasionally they can get stuck, and they are physical gates, so they can be forced to move again...