Ever wondered how the monitor that sits on your desk actually works? Bit-Tech has published pretty good guide with pictures to illustrate how the picture is formed. The article also has the disassembly of a LCD monitor to show what it's made up of inside and a look at future display technology.

The actual image on a TFT is made up of a matrix of pixels. Unlike with CRTs, there's no complex equation of dot pitch and image area to try and calculate - the native resolution of the monitor is simply the number of pixels contained in the matrix. If it's a 17" monitor, chances are there are 1280 pixels in the matrix horizontally, and 1024 vertically.

Each pixel is made up of three sub-pixels, which have red, green and blue filters in front of them, just as each pixel on a CRT has RGB phosphors. The subpixels are made up of a group of liquid crystal molecules. These molecules are suspended between transparent electrodes and are mashed between two polarising filters.

The two filters are exact opposites of each other. As the light from the light source behind the first filter comes in, the filter effectively whites it out - which means that if it was to pass through the liquid crystals with no interaction, the filter on the other side would polarise it back to black, leaving no colour being emitted. In fact, alternate current - leaving the crystals 'dead in the water' - is how black is created on a panel.

However, if the electrodes apply current to the liquid crystals they twist and change the way that the light is passed through, altering its polarisation and this then results in the correct colour coming out of the second polarising filter and being displayed to the user.

The backlight itself is a cold cathode. Depending on how expensive the display is, there will be either a single cathode at the top, or one at the top and one at the bottom, or two at the top and two at the bottom for optimum brightness and clarity. These cathodes are diffused through a layer of plastic and then through multiple layers of diffusing material of the kind you might find on a flashgun diffuser for photography.