The LCDs put for projection systems are generally small reflective or transmissive panels lit up by a powerful arc lamp source. A line of lenses enlarges the reflected or transmitted image and casts it onto a screen. With front-projection systems the LCD is set on the side of the screen as the viewer, while in rear-projection systems the screen is lit up from behind. Projectors of higher expense and capacity can use three separated LCD panels, reflecting separate red, green, and blue images that blend to reflect a coloured image on the screen.

The increasing desire for visual displays has placed a growing emphasis on the switching speed of liquid crystals. This has demanded the development of objects build with smectic liquid crystals, particular types of which give a faster electro-optical response than nematic liquid crystals. The surface-stabilized ferroelectric liquid crystal (SSFLC) display is in the current day the most sophisticated smectic device. With it the liquid crystal molecules are arranged in perpendicular layers to the substrate planes, which are separated by one or two micrometres, and throughout the layers the molecules are on a slant, as shown in the figure. The host liquid crystal contains optically active molecules, and a scarcely perceptible consequence of the optical activity and the tilt of the molecules is the appearance of a permanent charge separation, or ferroelectric dipole, comparable 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 through 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 in so doing reverse the tilt direction of the molecules. The respective change in optical properties can cause a change from light to dark when one or more polarizers are utilised.

SSFLC devices have been marketed for big passive-matrix presentations, but their cost and complex nature has impeded them from creating any significant progress on the market. Small transmissive and reflective active-matrix SSFLC displays, however, display some probability for use as elements in projection systems or as viewfinders in digital cameras. Their immediate response allows them to be utilised in time-sequential colour systems, in which costly colour filters are emulated by a coloured backlight that flashes red, green, and blue in rapid succession (approximately 100 cycles a 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 end result that the eye sees an average of red and green light, or the colour yellow.

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