The LCDs used in projection systems are generally small reflective or transmissive panels set off by a forceful arc lamp source. A series of lenses magnifies the reflected or transmitted image and casts it on a screen. With front-projection systems the LCD is set on the same area of the screen as the viewer, but in rear-projection systems the screen is lit up from behind. Projectors of greater expense and performance sometimes have three separate LCD panels, creating separate red, green, and blue images that mesh to create a coloured display on the screen.

The growing demand for video presentations has granted a growing emphasis on the switching speed of liquid crystals. This has demanded the creation of objects build with smectic liquid crystals, certain types of which possess a speedier electro-optical response than nematic liquid crystals. The surface-stabilized ferroelectric liquid crystal (SSFLC) display is at this time the most sophisticated smectic device. Within it the liquid crystal molecules are set out in layers perpendicular to the substrate planes, which are differentiated by one or two micrometres, and inside the layers the molecules are on a slant, as illustrated in the figure. The host liquid crystal possesses optically active molecules, and a subtle turn up of the optical activity and the tilt of the molecules is the presence 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 through the plane of the layers. Therefore, there exists a permanent charge separation over 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 correct sign can reverse the direction of this dipole in tens of microseconds and so reverse the tilt direction of the molecules. The corresponding change in optical properties can create a change from light to dark when one or more polarizers are used.

SSFLC devices have been commercialized for large passive-matrix presentations, but their expensiveness and intricacy has impeded them from having any remarkable impact on the market. Small transmissive and reflective active-matrix SSFLC displays, however, show some probability for use as elements in projection systems or as viewfinders in digital cameras. Their quick reaction allows them to be employed in time-sequential colour systems, in which costly colour filters are emulated by a coloured backlight that flashes red, green, and blue in quick pulsing (about 100 cycles per second). For example, the liquid crystal could be switched to a transmissive state during the red and green periods and then to a nontransmissive state in the blue period, having the end result that the eye sees an average of red and green light, or the colour yellow.

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