The LCDs used in projection systems are usually small reflective or transmissive panels set off by a bright arc lamp source. A line of lenses magnifies the reflected or transmitted image and sends it on a screen. With front-projection systems the LCD is placed on the side of the screen as the viewer, but in rear-projection systems the screen is lit up from behind. Projectors of higher expense and capacity may have three separate LCD panels, casting separate red, green, and blue images that combine to reflect a coloured image on the screen.

The increasing need for visual presentations has granted a growing emphasis on the switching speed of liquid crystals. This has led to the development of objects build with smectic liquid crystals, particular types of which have a speedier electro-optical response than nematic liquid crystals. The surface-stabilized ferroelectric liquid crystal (SSFLC) display is currently the most complex smectic device. With it the liquid crystal molecules are cast in perpendicular layers to the substrate planes, which are differentiated by one or two micrometres, and inside the layers the molecules are on a tilt, as shown in the figure. The host liquid crystal possesses optically active molecules, and a minor turn up of the optical activity and the shape of the molecules is the appearance of a permanent charge separation, or ferroelectric dipole, likeable to the ferromagnetic dipole of a magnet. The direction of this dipole is perpendicular to the tilt direction of the molecules and within the plane of the layers. Hence, there is a permanent charge separation over 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 hence reverse the tilt direction of the molecules. The consequential change in optical properties can make a change from light to dark if or when one or more polarizers are employed.

SSFLC devices have been publicized for large passive-matrix displays, but their high cost and complex nature has impeded them from making any remarkable effect on the market. Small transmissive and reflective active-matrix SSFLC displays, however, have shown some probability for use as elements in projection systems or as viewfinders in digital cameras. Their speedy response allows them to be employed in time-sequential colour systems, in which highly expensive colour filters are replaced by a coloured backlight that flashes red, green, and blue in fast pulsing (around 100 cycles every second). For example, the liquid crystal might be switched to a transmissive state for the red and green periods and then to a nontransmissive state in the blue period, with the outcome that the eye sees an average of red and green light, or the colour yellow.

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