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The LCDs utilised in projection systems are generally small reflective or transmissive panels lit by a powerful arc lamp source. A number of lenses magnifies the reflected or transmitted image and casts it onto the screen. With front-projection systems the LCD is set on the same area of the screen as the viewer, although in rear-projection systems the screen is illuminated from behind. Projectors of greater cost and performance can be found with three distinct LCD panels, creating separate red, green, and blue images that blend to create a coloured picture on the screen.

The increase in need for video displays has put a particular emphasis on the switching speed of liquid crystals. This has led to the development of items build with smectic liquid crystals, some kinds of which have 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 arranged in layers that are perpendicular to the substrate planes, which are differentiated by one or two micrometres, and inside the layers the molecules are on a slant, as shown in the figure. The host liquid crystal holds optically active molecules, and a minor turn up of the optical activity and the shape of the molecules is the presence of a permanent charge separation, or ferroelectric dipole, analogous 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. Hence, there has to be a permanent charge separation throughout 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 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 create a change from light to dark when one or more polarizers are employed.

SSFLC devices have been marketed for larger passive-matrix displays, but their expense and complexity has prevented them from enjoying any remarkable movement on the market. Small transmissive and reflective active-matrix SSFLC displays, however, have displayed some probability for use as parts in projection systems or as viewfinders in digital cameras. Their quick responding allows them to be used in time-sequential colour systems, in which highly expensive colour filters are removed for a coloured backlight that flashes red, green, and blue in quick pulsing (approx 100 cycles every second). For example, the liquid crystal might be switched to a transmissive state for the red and green periods then to a nontransmissive state during the blue period, having the result that the eye sees an average of red and green light, or the colour yellow.

For help with choosing and purchasing your data projector, contact projectors brisbane and projectors gold coast.