The main part of an LCD is transparent. It looks like they've stacked one in front of the other, with a half-pixel offset, and arranged the polarizers in such

The main part of an LCD is transparent. It looks like they've stacked one in front of the other, with a half-pixel offset, and arranged the polarizers in such a way that they perform a multiply operation. So, two panels can produce 4X the resolution, using only static images. But I'm guessing they'd have to sacrifice some bits in the luminosity domain to make it work.