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The LCDs utilised in projection systems are usually small reflective or transmissive panels lit by a bright arc lamp source. A number of lenses magnifies the reflected or transmitted image then sends it onto the screen. With front-projection systems the LCD is placed on the side of the screen as the viewer, although in rear-projection systems the screen is set off from behind. Projectors of greater expense and capability can be found with three separate LCD panels, creating separate red, green, and blue images that come together to form a coloured display on the screen.

The increase in requirement for film presentations has had a special emphasis on the switching speed of liquid crystals. This has required the creation of devices employing smectic liquid crystals, certain kinds of which possess a faster electro-optical response than nematic liquid crystals. The surface-stabilized ferroelectric liquid crystal (SSFLC) display is currently the most complex smectic device. Inside it the liquid crystal molecules are cast in layers perpendicular to the substrate planes, which are differentiated by one or two micrometres, and throughout the layers the molecules are on a tilt, as demonstrated in the figure. The host liquid crystal has optically active molecules, and a scarcely perceptible result of the optical activity and the angle 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. Thus, there must be a permanent charge separation across the liquid crystal layer in the SSFLC, and its sign is directly attracted 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 hence reverse the tilt direction of the molecules. The consequential change in optical properties can create a change from light to dark if or when one or more polarizers are utilised.

SSFLC devices have been marketed for big passive-matrix displays, but their cost and complex detail has stopped them from having any significant progress on the market. Small transmissive and reflective active-matrix SSFLC displays, however, have shown some possibility for use as aspects in projection systems or as viewfinders in digital cameras. Their fast reacting allows them to be made use of in time-sequential colour systems, in which dear colour filters are removed for a coloured backlight that flashes red, green, and blue in fast succession (around 100 cycles a second). For example, the liquid crystal can be switched to a transmissive state in the red and green periods and to a nontransmissive state for the blue period, displaying the result that the eye sees an average of red and green light, or the colour yellow.

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