How do smectic liquid crystal displays switch faster than nematic LCDs?

Smectic liquid crystal displays, specifically those utilizing surface-stabilized ferroelectric liquid crystal (SSFLC) technology, achieve faster switching speeds than nematic displays due to the presence of a permanent charge separation, or ferroelectric dipole.1

In these smectic devices, the liquid crystal molecules are arranged in layers with a specific tilt. Because the host material contains optically active molecules, a permanent ferroelectric dipole is created that is perpendicular to the molecular tilt direction and lies within the plane of the layers. This dipole is directly coupled to the tilt direction of the molecules.1

When an external voltage of the appropriate sign is applied, it interacts with this permanent dipole, allowing the device to reverse the tilt direction of the molecules in tens of microseconds. This rapid electro-optical response is significantly faster than that of nematic liquid crystals, enabling applications such as time-sequential color systems where the display must switch states in rapid succession.1