DSTN is short for double-layer supertwisted nematic. It is a technology used to manufacture flat-panel displays, such as those found on computer monitors and televisions.
An improvement on STN, DSTN is a passive-matrix display technology that divides the screen in half. This method allows twice as many lines to be refreshed each second, resulting in images that are sharper.
DSTN screens are also referred to as dual scan screens.