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The LCDs used for projection systems are most often small reflective or transmissive panels lit by a forceful arc lamp source. A number of lenses expands the reflected or transmitted image then sends it onto a screen. With front-projection systems the LCD is located on the same side of the screen as the viewer, while in rear-projection systems the screen is lit up from behind. Projectors of greater cost and capability might have three discrete LCD panels, reflecting separate red, green, and blue images that mesh to create a coloured image on the screen.

The increasing demand for video presentations has put a special emphasis on the switching speed of liquid crystals. This has required the development of items build with smectic liquid crystals, certain ones of which emit a quicker electro-optical response than nematic liquid crystals. The surface-stabilized ferroelectric liquid crystal (SSFLC) display is in the current day the most developed smectic device. In it the liquid crystal molecules are arranged in layers perpendicular to the substrate planes, which are separated by one or two micrometres, and within the layers the molecules are slanted, as demonstrated in the figure. The host liquid crystal contains optically active molecules, and a subtle turn up of the optical activity and the slant of the molecules is the appearance 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 in the plane of the layers. Thus, there has to be a permanent charge separation through the liquid crystal layer in the SSFLC, and its sign is directly coupled to the tilt direction of the molecules. An applied voltage of the right sign can reverse the direction of this dipole in tens of microseconds and so reverse the tilt direction of the molecules. The consequential change in optical properties can create a change from light to dark if one or more polarizers are utilised.

SSFLC devices have been produced for larger passive-matrix presentations, but their high cost and intricacy has prevented them from making any significant movement on the market. Small transmissive and reflective active-matrix SSFLC displays, however, have shown some promise for use as aspects in projection systems or as viewfinders in digital cameras. Their immediate reacting allows them to be employed in time-sequential colour systems, in which high cost colour filters are removed for a coloured backlight that flashes red, green, and blue in fast speed (approx 100 cycles per second). For example, the liquid crystal might be switched to a transmissive state in the red and green periods and to a nontransmissive state in the blue period, with the upshot that the eye sees an average of red and green light, or the colour yellow.

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