The LCDs used in projection systems are usually small reflective or transmissive panels lit up by a powerful arc lamp source. A line of lenses enlarges the reflected or transmitted image then displays it on the screen. With front-projection systems the LCD is situated on the same side of the screen as the viewer, although in rear-projection systems the screen is lit from behind. Projectors of higher expense and capability can have three distinct LCD panels, forming separate red, green, and blue images that blend to form a coloured picture on the screen.

The growth in demand for pictographic presentations has put a particular emphasis on the switching speed of liquid crystals. This has necessitated the development of devices build with smectic liquid crystals, some types of which possess a quicker electro-optical response than nematic liquid crystals. The surface-stabilized ferroelectric liquid crystal (SSFLC) display is at this point the most developed smectic device. With it the liquid crystal molecules are managed in layers that are perpendicular to the substrate planes, which are distanced by one or two micrometres, and in the layers the molecules are on a tilt, as demonstrated in the figure. The host liquid crystal possesses optically active molecules, and a slight outcome of the optical activity and the slant of the molecules is the presence of a permanent charge separation, or ferroelectric dipole, similar to the ferromagnetic dipole of a magnet. The direction of this dipole is perpendicular to the tilt direction of the molecules and through the plane of the layers. So, there is a permanent charge separation through the liquid crystal layer in the SSFLC, and its sign is directly partnered to the tilt direction of the molecules. An applied voltage of the correct sign can reverse the direction of this dipole in tens of microseconds and therefore reverse the tilt direction of the molecules. The resultant change in optical properties can create a change from light to dark if or when one or more polarizers are used.

SSFLC devices have been commercialized for bigger passive-matrix presentations, but their expensiveness and complex nature has stopped them from enjoying any remarkable effect on the market. Small transmissive and reflective active-matrix SSFLC displays, however, have displayed some possibility for use as elements in projection systems or as viewfinders in digital cameras. Their quick responding allows them to be utilised in time-sequential colour systems, in which costly colour filters are emulated with a coloured backlight that flashes red, green, and blue in quick succession (approx 100 cycles in a second). For example, the liquid crystal can be switched to a transmissive state in the red and green periods then to a nontransmissive state for the blue period, with the end result that the eye sees an average of red and green light, or the colour yellow.

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