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The LCDs utilised in projection systems are typically small reflective or transmissive panels lit up by a powerful arc lamp source. A series of lenses expands the reflected or transmitted image then casts it on a screen.

For 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 illuminated from behind. Projectors of greater expense and performance might utilise three separate LCD panels, casting separate red, green, and blue images that blend to create a coloured picture on the screen.

The increasing desire for film presentations has granted a growing emphasis on the switching speed of liquid crystals. This has required the development of devices using smectic liquid crystals, certain types of which emit a quicker electro-optical response than nematic liquid crystals.

The surface-stabilized ferroelectric liquid crystal (SSFLC) display is at this time the most progressive smectic device. Within it the liquid crystal molecules are cast in layers perpendicular to the substrate planes, which are distanced by one or two micrometres, and throughout the layers the molecules are slanted, as shown in the figure.

The host liquid crystal holds optically active molecules, and a minor outcome of the optical activity and the angle 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 within 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 paired 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 make a change from light to dark if or when one or more polarizers are utilised.

SSFLC devices have been produced for big passive-matrix displays, but their cost and complex detail has stopped them from having any great movement on the market. Small transmissive and reflective active-matrix SSFLC displays, however, have some possibility for use as aspects in projection systems or as viewfinders in digital cameras. Their speedy response allows them to be made use of in time-sequential colour systems, in which highly expensive colour filters are emulated by a coloured backlight that flashes red, green, and blue in rapid speed (around 100 cycles in a second). For example, the liquid crystal may be switched to a transmissive state between the red and green periods and to a nontransmissive state for 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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