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The LCDs used for projection systems are typically small reflective or transmissive panels lit by a forceful arc lamp source. A number of lenses expands the reflected or transmitted image and then displays it on the screen. For front-projection systems the LCD is placed on the side of the screen as the viewer, although in rear-projection systems the screen is illuminated from behind. Projectors of more expense and capability might have three discrete LCD panels, casting separate red, green, and blue images that blend to form a coloured display on the screen.

The increase in demand for video displays has granted a growth in emphasis on the switching speed of liquid crystals. This has led to the creation of objects utilizing smectic liquid crystals, some kinds of which emit a better electro-optical response than nematic liquid crystals. The surface-stabilized ferroelectric liquid crystal (SSFLC) display is at this point the most developed smectic device. Within it the liquid crystal molecules are cast in perpendicular layers to the substrate planes, which are differentiated by one or two micrometres, and within the layers the molecules are slanted, as demonstrated in the figure. The host liquid crystal has optically active molecules, and a scarcely perceptible turn up 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 in 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 hence reverse the tilt direction of the molecules. The corresponding change in optical properties can effect a change from light to dark when one or more polarizers are used.

SSFLC devices have been commercialized for big passive-matrix displays, but their high cost and complex detail has prevented them from having any particular effect on the market. Small transmissive and reflective active-matrix SSFLC displays, however, have displayed some probability for use as elements in projection systems or as viewfinders in digital cameras. Their speedy reacting allows them to be used in time-sequential colour systems, in which expensive colour filters are emulated by a coloured backlight that flashes red, green, and blue in rapid pulsing (approximately 100 cycles per 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 for the blue period, having the outcome 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.