Liquid Crystal Display technology uses an array of liquid crystals sandwiched between two sheets of polarised filters to control the amount of light generated by a cold cathode tube allowed to pass through to the front of the screen. The polarising filters are arranged in different directions of polarity, so that the light coming through one filter will be completely blocked by the other, in the absence of the layer of liquid crystals. The shape of the liquid crystal influences the amount of light passing through the second filter. By varying the voltage applied to the liquid crystal, its shape can be controlled. In colour LCDs, one pixel is made up of three liquid crystals, each coloured Red, Green, or Blue.