The technology they use is similar to the parallax barrier screens on the Nintendo 3DS, which is made by Sharp, and the one LG developed for its LG Optimus 3D and T-Mobile G-Slate devices with 3D capabilities.
The MasterImage 3D overlay is supposedly adding only $10-$15 to the manufacturing costs of an LCD or OLED screen for the 3D capability, that is why we are seeing prices on these handsets in line with all other high-end smartphones. It can also be turned on and off at will.
It certainly seems that Samsung is changing its mind over 3D, compared to a few weeks ago when it dismissed it as making phones bulky, but said it will be ready to produce 3D-enabled handsets, if people like them enough. Investing in MasterImage 3D seems to be the first step in that direction, considering the LG Optimus 3D, and now the HTC EVO 3D and LG Thrill 4G, have been stealing the spotlight at the MWC and CTIA wireless expos this year.
source: MasterImage & DigitalNinja