I am sorry but can anyone tell me whats the difference, technology wise, between the normal LCD and 3D capable LCD TV?

One thing I can never understand thus far is this, last time the 3D movie project double image in two images superimposed to each other, but in different polarity. So if one wear polarised glasses, one eye will see each polarised image, perpendicular to each other in order to hide one image at any one time.

How does 3D LCD works ? I try to read the online info but somehow still cannot understand the technique to 'hide' one image from one eye and vice versa.

Sorry I digress from the topic. But I am very curious.