The LCDs utilised for projection systems are usually small reflective or transmissive panels set off by a bright arc lamp source. A series of lenses enlarges the reflected or transmitted image and displays it on a screen. With front-projection systems the LCD is placed on the side of the screen as the viewer, however in rear-projection systems the screen is set off from behind. Projectors of greater expense and capacity may have three distinct LCD panels, reflecting separate red, green, and blue images that combine to reflect a coloured picture on the screen.

The increasing requirement for pictographic displays has had a particular emphasis on the switching speed of liquid crystals. This has demanded the manufacture of devices utilizing smectic liquid crystals, some of which give a quicker electro-optical response than nematic liquid crystals. The surface-stabilized ferroelectric liquid crystal (SSFLC) display is currently the most sophisticated smectic device. Within it the liquid crystal molecules are set out in layers that are perpendicular to the substrate planes, which are distanced by one or two micrometres, and inside the layers the molecules are on a slant, as displayed in the figure. The host liquid crystal possesses optically active molecules, and a subtle outcome of the optical activity and the tilt 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 in the plane of the layers. Hence, there exists 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 corresponding sign can reverse the direction of this dipole in tens of microseconds and so reverse the tilt direction of the molecules. The respective change in optical properties can cause 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 expense and detail has impeded them from creating any particular effect on the market. Small transmissive and reflective active-matrix SSFLC displays, however, have some promise for use as elements in projection systems or as viewfinders in digital cameras. Their speedy reacting allows them to be utilised in time-sequential colour systems, in which high cost colour filters are emulated by a coloured backlight that flashes red, green, and blue in fast succession (about 100 cycles per second). For example, the liquid crystal could be switched to a transmissive state between the red and green periods then to a nontransmissive state during the blue period, having the upshot that the eye sees an average of red and green light, or the colour yellow.

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